WorldWideScience

Sample records for linearly polarized synchrotron

  1. Techniques of production and analysis of polarized synchrotron radiation

    International Nuclear Information System (INIS)

    Mills, D.M.

    1992-01-01

    The use of the unique polarization properties of synchrotron radiation in the hard x-ray spectral region (E>3 KeV) is becoming increasingly important to many synchrotron radiation researchers. The radiation emitted from bending magnets and conventional (planar) insertion devices (IDs) is highly linearly polarized in the plane of the particle's orbit. Elliptically polarized x-rays can also be obtained by going off axis on a bending magnet source, albeit with considerable loss of flux. The polarization properties of synchrotron radiation can be further tailored to the researcher's specific needs through the use of specialized insertion devices such as helical and crossed undulators and asymmetrical wigglers. Even with the possibility of producing a specific polarization, there is still the need to develop x-ray optical components which can manipulate the polarization for both analysis and further modification of the polarization state. A survey of techniques for producing and analyzing both linear and circular polarized x-rays will be presented with emphasis on those techniques which rely on single crystal optical components

  2. Experimental method for investigating γd→pn photodisintegration reaction on the linearly polarized photon beam of the Erevan synchrotron

    International Nuclear Information System (INIS)

    Agababyan, K.Sh.; Adamyan, F.V.; Ajrapetyan, A.V.

    1985-01-01

    The experimental method for measuring the asymmetry of the γd → pn photodisintegration reaction on the linearly polarized photon beam of the Erevan synchrotron is described. The results of Monte Carlo calculations, the calibration of apparatus, the procedure of measurements and experimental data processing are repored

  3. Application of circular polarized synchrotron radiation

    International Nuclear Information System (INIS)

    Miyahara, Tsuneaki; Kawata, Hiroshi

    1988-03-01

    The idea of using the polarizing property of light for physical experiment by controlling it variously has been known from old time, and the Faraday effect and the research by polarizing microscopy are its examples. The light emitted from the electron orbit of an accelerator has the different polarizing characteristics from those of the light of a laboratory light source, and as far as observing it within the electron orbit plane, it becomes linearly polarized light. By utilizing this property well, research is carried out at present in synchrotron experimental facilities. Recently, the technology related to the insert type light cources using permanent magnets has advanced remarkably, and circular polarized light has become to be producible. If the light like this can be obtained with the energy not only in far ultraviolet region but also to x-ray region at high luminance, new possibility should open. At the stage that the design of an insert type light source was finished, and its manufacture was started, the research on the method of evaluating the degree of circular polarization and the research on the utilization of circular polarized synchrotron radiation are earnestly carried out. In this report, the results of researches presented at the study meeting are summarized. Moreover, the design and manufacture of the beam lines for exclusive use will be carried out. (Kako, I.)

  4. 3D printed polarizing grids for IR-THz synchrotron radiation

    Science.gov (United States)

    Ryu, Meguya; Linklater, Denver; Hart, William; Balčytis, Armandas; Skliutas, Edvinas; Malinauskas, Mangirdas; Appadoo, Dominique; Tan, Yaw-Ren Eugene; Ivanova, Elena P.; Morikawa, Junko; Juodkazis, Saulius

    2018-03-01

    Grid polarisers 3D-printed out of commercial acrilic resin were tested for the polariser function and showed spectral regions where the dichroic ratio {D}R> 1 and The used 3D printing method allows for fabrication of an arbitrary high aspect ratio grid polarisers. Polarization analysis of synchrotron THz radiation was carried out with a standard stretched polyethylene polariser and revealed that the linearly polarized (horizontal) component contributes up to 22% ± 5% to the circular polarized synchrotron emission extracted by a gold-coated mirror with a horizontal slit inserted near the bending magnet edge. Comparison with theoretical predictions shows a qualitative match with dominance of the edge radiation.

  5. Sources of linear polarized x-rays

    International Nuclear Information System (INIS)

    Aiginger, H.; Wobrauschek, P.

    1989-01-01

    Linear polarized X-rays are used in X-ray fluorescence analysis to decrease the background caused by scattered photons. Various experiments, calculations and constructions have demonstrated the possibility to produce polarized radiation in an analytical laboratory with an X-ray tube and polarizer-analyzer facilities as auxiliary equipment. The results obtained with Bragg-polarizers of flat and curved focussing geometry and of Barkla-polarizers are presented. The advantages and disadvantages of the method are discussed and compared with the respective quality of synchrotron radiation. Polarization by scattering reduces the intensity of the primary radiation. Recently much effort is devoted to the construction of integrated high power X-ray tube polarizer-analyzer arrangements. The detailed design, geometry and performance of such a facility is described. (author)

  6. Modeling and parameterization of photoelectrons emitted in condensed matter by linearly polarized synchrotron radiation

    Science.gov (United States)

    Jablonski, A.

    2018-01-01

    Growing availability of synchrotron facilities stimulates an interest in quantitative applications of hard X-ray photoemission spectroscopy (HAXPES) using linearly polarized radiation. An advantage of this approach is the possibility of continuous variation of radiation energy that makes it possible to control the sampling depth for a measurement. Quantitative applications are based on accurate and reliable theory relating the measured spectral features to needed characteristics of the surface region of solids. A major complication in the case of polarized radiation is an involved structure of the photoemission cross-section for hard X-rays. In the present work, details of the relevant formalism are described and algorithms implementing this formalism for different experimental configurations are proposed. The photoelectron signal intensity may be considerably affected by variation in the positioning of the polarization vector with respect to the surface plane. This information is critical for any quantitative application of HAXPES by polarized X-rays. Different quantitative applications based on photoelectrons with energies up to 10 keV are considered here: (i) determination of surface composition, (ii) estimation of sampling depth, and (iii) measurements of an overlayer thickness. Parameters facilitating these applications (mean escape depths, information depths, effective attenuation lengths) were calculated for a number of photoelectron lines in four elemental solids (Si, Cu, Ag and Au) in different experimental configurations and locations of the polarization vector. One of the considered configurations, with polarization vector located in a plane perpendicular to the surface, was recommended for quantitative applications of HAXPES. In this configurations, it was found that the considered parameters vary weakly in the range of photoelectron emission angles from normal emission to about 50° with respect to the surface normal. The averaged values of the mean

  7. Knot Undulator to Generate Linearly Polarized Photons with Low on-Axis Power Density

    International Nuclear Information System (INIS)

    Qiao, S.

    2009-01-01

    Heat load on beamline optics is a serious problem to generate pure linearly polarized photons in the third generation synchrotron radiation facilities. For permanent magnet undulators, this problem can be overcome by a figure-8 operating mode. But there is still no good method to tackle this problem for electromagnetic elliptical undulators. Here, a novel operating mode is suggested, which can generate pure linearly polarized photons with very low on-axis heat load. Also the available minimum photon energy of linearly polarized photons can be extended much by this method.

  8. On the polarized beam acceleration in medium energy synchrotrons

    International Nuclear Information System (INIS)

    Lee, S.Y.

    1992-01-01

    This lecture note reviews physics of spin motion in a synchrotron, spin depolarization mechanisms of spin resonances, and methods of overcoming the spin resonances during acceleration. Techniques used in accelerating polarized ions in the low/medium energy synchrotrons, such as the ZGS, the AGS, SATURNE, and the KEK PS and PS Booster are discussed. Problems related to polarized proton acceleration with snakes or partial snake are also examined

  9. On the polarized beam acceleration in medium energy synchrotrons

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.Y.

    1992-12-31

    This lecture note reviews physics of spin motion in a synchrotron, spin depolarization mechanisms of spin resonances, and methods of overcoming the spin resonances during acceleration. Techniques used in accelerating polarized ions in the low/medium energy synchrotrons, such as the ZGS, the AGS, SATURNE, and the KEK PS and PS Booster are discussed. Problems related to polarized proton acceleration with snakes or partial snake are also examined.

  10. Synchrotron Radiation and Faraday Rotation

    NARCIS (Netherlands)

    Heald, George

    2015-01-01

    Synchrotron radiation and its degree of linear polarization are powerful tracers of magnetic fields that are illuminated by cosmic ray electrons. Faraday rotation of the linearly polarized radiation is induced by intervening line-of-sight magnetic fields that are embedded in ionized plasmas. For

  11. A survey of synchrotron radiation devices producing circular or variable polarization

    International Nuclear Information System (INIS)

    Kim, K.J.

    1990-01-01

    This paper reviews the properties and operating principles of the new types of synchrotron radiation devices that produce circular polarization, or polarization that can be modulated in arbitrary fashion

  12. On the possibility of obtaining high-energy polarized electrons on Yerevan synchrotron

    International Nuclear Information System (INIS)

    Melikyan, R.A.

    1975-01-01

    A possibility of producing high-energy polarized electrons on the Yerevan synchrotron is discussed. A review of a number of low-energy polarized electron sources and of some of experiments with high-energy polarized electrons is given

  13. Quantitative investigation of linear arbitrary polarization in an APPLE-II undulator.

    Science.gov (United States)

    Hand, Matthew; Wang, Hongchang; Maccherozzi, Francesco; Apollonio, Marco; Zhu, Jingtao; Dhesi, Sarnjeet S; Sawhney, Kawal

    2018-03-01

    Insertion devices are utilized at synchrotron radiation facilities around the world for their capability to provide a high-brilliance X-ray beam. APPLE-II type undulators are especially important for their capacity to switch between a variety of photon beam polarization states. A high-precision soft X-ray polarimeter has been used to investigate the polarization calibration of an APPLE-II undulator (period length λ u = 64 mm) installed on beamline I06 at Diamond Light Source. Systematic measurement of the beam polarization state at a range of linear arbitrary angles has been compared with the expected result for a given set of undulator gap and row phase parameters calculated from theory. Determination of the corresponding Stokes-Poincaré parameters from the measured data reveals a discrepancy between the two. The limited number of energy/polarization combinations included in the undulator calibration tables necessitates the use of interpolated values for the missing points which is expected to contribute to the discrepancy. However, by modifying the orbit of the electron beam through the undulator by at least 160 µm it has been found that for certain linear polarizations the discrepancies can be corrected. Overall, it is suggested that complete correction of the Stokes-Poincaré parameters for all linear angles would require alteration of both these aspects.

  14. Advanced Diagnostics for the Study of Linearly Polarized Emission. II. Application to Diffuse Interstellar Radio Synchrotron Emission

    Science.gov (United States)

    Herron, C. A.; Burkhart, Blakesley; Gaensler, B. M.; Lewis, G. F.; McClure-Griffiths, N. M.; Bernardi, G.; Carretti, E.; Haverkorn, M.; Kesteven, M.; Poppi, S.; Staveley-Smith, L.

    2018-03-01

    Diagnostics of polarized emission provide us with valuable information on the Galactic magnetic field and the state of turbulence in the interstellar medium, which cannot be obtained from synchrotron intensity alone. In Paper I, we derived polarization diagnostics that are rotationally and translationally invariant in the Q–U plane, similar to the polarization gradient. In this paper, we apply these diagnostics to simulations of ideal magnetohydrodynamic turbulence that have a range of sonic and Alfvénic Mach numbers. We generate synthetic images of Stokes Q and U for these simulations for the cases where the turbulence is illuminated from behind by uniform polarized emission and where the polarized emission originates from within the turbulent volume. From these simulated images, we calculate the polarization diagnostics derived in Paper I for different lines of sight relative to the mean magnetic field and for a range of frequencies. For all of our simulations, we find that the polarization gradient is very similar to the generalized polarization gradient and that both trace spatial variations in the magnetoionic medium for the case where emission originates within the turbulent volume, provided that the medium is not supersonic. We propose a method for distinguishing the cases of emission coming from behind or within a turbulent, Faraday rotating medium and a method to partly map the rotation measure of the observed region. We also speculate on statistics of these diagnostics that may allow us to constrain the physical properties of an observed turbulent region.

  15. Coherent synchrotron radiation by an electron linear accelerator

    International Nuclear Information System (INIS)

    Nakazato, T.; Oyamada, M.; Niimura, N.

    1990-01-01

    Coherent effects in synchrotron radiation (SR) have been observed for the first time from 180 MeV short electron bunches of 1.7 mm using the Tohoku 300 MeV Linac. The intensity of the coherent SR was about 10 5 times as strong as that of incoherent SR at wavelengths of 0.33 to 2.0 mm. This enhancement factor roughly corresponds to the number of electrons in a bunch. The SR intensity showed a quadratic dependence on the electron beam current. The radiation was mainly polarized in the orbital plane. The possibility of induced rf in a vacuum chamber was excluded experimentally. An electron linear accelerator will be applied to a strong light source from infrared to millimeter wavelengths instead of the storage rings. The bunch length of shorter than 1 mm can be observed by the spectrum measurement of coherent SR. (author)

  16. Simulations of Galactic polarized synchrotron emission for Epoch of Reionization observations

    Science.gov (United States)

    Spinelli, M.; Bernardi, G.; Santos, M. G.

    2018-06-01

    The detection of the redshifted cosmological 21 cm line signal requires the removal of the Galactic and extragalactic foreground emission, which is orders of magnitude brighter anywhere in the sky. Foreground cleaning methods currently used are efficient in removing spectrally smooth components. However, they struggle in the presence of not spectrally smooth contamination that is, therefore, potentially the most dangerous one. An example of this is the polarized synchrotron emission, which is Faraday rotated by the interstellar medium and leaks into total intensity due to instrumental imperfections. In this work we present new full-sky simulations of this polarized synchrotron emission in the 50 - 200 MHz range, obtained from the observed properties of diffuse polarized emission at low frequencies. The simulated polarized maps are made publicly available, aiming to provide more realistic templates to simulate the effect of instrumental leakage and the effectiveness of foreground separation techniques.

  17. Materials science created by synchrotron radiation

    International Nuclear Information System (INIS)

    Oshima, Masaharu

    2015-01-01

    We survey the use of synchrotron radiation for studies on oxides. High luminosity enables the spectroscopy with high energy-resolution in soft X-ray and vacuum ultraviolet region. Element analysis is possible by examining absorption edge in the X-ray absorption spectra. Time-resolved measurements are possible due to the pulsed nature of the radiation. The radiation can bear linear or circular polarization. The feature of molecules adhered on a surface can be clarified by using linearly polarized radiation. The circularly polarized radiation, on the other hand, clarifies the magnetic structure. The structure information so far unknown can be obtained by using space- or time-coherent radiation. We show studies using synchrotron radiation on LSI gate oxide foils, variable resistance RAM, strongly correlated oxide foils, and the oxide as positive electrode of Li ion battery. (J.P.N.)

  18. On some methods to produce high-energy polarized electron beams by means of proton synchrotrons

    International Nuclear Information System (INIS)

    Bessonov, E.G.; Vazdik, Ya.A.

    1980-01-01

    Some methods of production of high-energy polarized electron beams by means of proton synchrotrons are considered. These methods are based on transfer by protons of a part of their energy to the polarized electrons of a thin target placed inside the working volume of the synchrotron. It is suggested to use as a polarized electron target a magnetized crystalline iron in which proton channeling is realized, polarized atomic beams and the polarized plasma. It is shown that by this method one can produce polarized electron beams with energy approximately 100 GeV, energy spread +- 5 % and intensity approximately 10 7 electron/c, polarization approximately 30% and with intensity approximately 10 4 -10 5 electron/c, polarization approximately 100% [ru

  19. 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.

  20. 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.

  1. Polarized Electrons for Linear Colliders

    International Nuclear Information System (INIS)

    Clendenin, J.

    2004-01-01

    Future electron-positron linear colliders require a highly polarized electron beam with a pulse structure that depends primarily on whether the acceleration utilizes warm or superconducting rf structures. The International Linear Collider (ILC) will use cold structures for the main linac. It is shown that a dc-biased polarized photoelectron source such as successfully used for the SLC can meet the charge requirements for the ILC micropulse with a polarization approaching 90%

  2. Acceleration of polarized electrons in the Bonn synchrotron and the planned stretcher ring ELSA

    International Nuclear Information System (INIS)

    Brefeld, W.

    1981-10-01

    In the last year at the synchrotron polarized electrons were successfully accelerated. For this the polarization vector in the transfer channel between source and LINAC was rotated in such a way that the electrons can be injected into the accelerator with the necessary vertical polarization. It was shown that the degree of polarization of the electrons after passing of the imperfection resonances at 0.441 GeV, 0.881 GeV, 1.322 GeV, and 1.763 GeV and the intrinsic resonance at 1.498 GeV remained conserved at a high degree also without additional procedures. Although it is desirable to reduce the present depolarization. First attempts for overcoming the second resonance were performed. The results indicate that for this a system of two pulse dipoles doesn't suffice. For the answer of this question however a much more intensive polarized source is needed. At ELSA the working with polarized electrons seems to be possible in the whole energy range if it succeeds to circumvent the position of the intrinsic resonance dependent from the working point. Though the imperfection resonances at 2.203 GeV, 2.644 GeV, and 3.085 GeV can depolarize the electrons much more strongly because of the relatively slow passing through the resonances an overcoming with pulse dipoles should by possible. Because of the large resonance time-distances the dipoles have much more time than in the synchrotron to reach the required value steadily. (orig.) [de

  3. Linear polarization of BY Draconis

    International Nuclear Information System (INIS)

    Koch, R.H.; Pfeiffer, R.J.

    1976-01-01

    Linear polarization measurements are reported in four bandpasses for the flare star BY Dra. The red polarization is intrinsically variable at a confidence level greater than 99 percent. On a time scale of many months, the variability is not phase-locked to either a rotational or a Keplerian ephemeris. The observations of the three other bandpasses are useful principally to indicate a polarization spectrum rising toward shorter wavelengths

  4. Simulations of X-ray synchrotron beams using the EGS4 code system in medical applications

    International Nuclear Information System (INIS)

    Orion, I.; Henn, A.; Sagi, I.; Dilmanian, F.A.; Pena, L.; Rosenfeld, A.B.

    2001-01-01

    X-ray synchrotron beams are commonly used in biological and medical research. The availability of intense, polarized low-energy photons from the synchrotron beams provides a high dose transfer to biological materials. The EGS4 code system, which includes the photoelectron angular distribution, electron motion inside a magnetic field, and the LSCAT package, found to be the appropriate Monte Carlo code for synchrotron-produced X-ray simulations. The LSCAT package was developed in 1995 for the EGS4 code to contain the routines to simulate the linear polarization, the bound Compton, and the incoherent scattering functions. Three medical applications were demonstrated using the EGS4 Monte Carlo code as a proficient simulation code system for the synchrotron low-energy X-ray source. (orig.)

  5. Uniform irradiation using rotational-linear scanning method for narrow synchrotron radiation beam

    International Nuclear Information System (INIS)

    Nariyama, N.; Ohnishi, S.; Odano, N.

    2004-01-01

    At SPring-8, photon intensity monitors for synchrotron radiation have been developed. Using these monitors, the responses of radiation detectors and dosimeters to monoenergetic photons can be measured. In most cases, uniform irradiation to the sample is necessary. Here, two scanning methods are proposed. One is an XZ-linear scanning method, which moves the sample simultaneously in both the X and Z direction, that is, in zigzag fashion. The other is a rotational-linear scanning method, which rotates the sample moving in the X direction. To investigate the validity of the two methods, thermoluminescent dosimeters were irradiated with a broad synchrotron-radiation beam, and the readings from the two methods were compared with that of the dosimeters fixed in the beam. The results for both scanning methods virtually agreed with that of the fixed method. The advantages of the rotational-linear scanning method are that low- and medium-dose irradiation is possible, uniformity is excellent and the load to the scanning equipment is light: hence, this method is superior to the XZ-linear scanning method for most applications. (author)

  6. Synchrotron x-ray fluorescence and extended x-ray absorption fine structure analysis

    International Nuclear Information System (INIS)

    Chen, J.R.; Gordon, B.M.; Hanson, A.L.; Jones, K.W.; Kraner, H.W.; Chao, E.C.T.; Minkin, J.A.

    1984-01-01

    The advent of dedicated synchrotron radiation sources has led to a significant increase in activity in many areas of science dealing with the interaction of x-rays with matter. Synchrotron radiation provides intense, linearly polarized, naturally collimated, continuously tunable photon beams, which are used to determine not only the elemental composition of a complex, polyatomic, dilute material but also the chemical form of the elements with improved accuracy. Examples of the application of synchrotron radiation include experiments in synchrotron x-ray fluorescence (SXRF) analysis and extended x-ray absorption fine structure (EXAFS) analysis. New synchrotron radiation x-ray microprobes for elemental analysis in the parts per billion range are under construction at several laboratories. 76 references, 24 figures

  7. Polarized electron sources for linear colliders

    International Nuclear Information System (INIS)

    Clendenin, J.E.; Ecklund, S.D.; Miller, R.H.; Schultz, D.C.; Sheppard, J.C.

    1992-07-01

    Linear colliders require high peak current beams with low duty factors. Several methods to produce polarized e - beams for accelerators have been developed. The SLC, the first linear collider, utilizes a photocathode gun with a GaAs cathode. Although photocathode sources are probably the only practical alternative for the next generation of linear colliders, several problems remain to be solved, including high voltage breakdown which poisons the cathode, charge limitations that are associated with the condition of the semiconductor cathode, and a relatively low polarization of ≤5O%. Methods to solve or at least greatly reduce the impact of each of these problems are at hand

  8. Synchrotron radiation sources: general features and vacuum system

    International Nuclear Information System (INIS)

    Craievich, A.F.

    1985-01-01

    In the last years the electron or positron storage rings, which were until 1970 only used for high energy physics experiments, begun to be built in several countries exclusively as electromagnetic radiation source (synchrotron radiation). The sources are generally made up by injector (linear accelerator or microtron), 'booster' (synchrotron), storage ring, insertions ('Wigglers' and ondulators) and light lines. The interest by these sources are due to the high intensity, large spectrum (from infrared to the X-rays), polarization and pulsed structure of the produced radiation. For the ultra-vacuum obtainement, necessary for the functioning storage rings (p=10 -9 Torr), several special procedures are used. In Brazil the Synchrotron Radiation National Laboratory of the CNPq worked out a conceptual project of synchrotron radiation source, whose execution should begin by the construction of the several components prototypes. (L.C.) [pt

  9. FDTD simulation of trapping nanowires with linearly polarized and radially polarized optical tweezers.

    Science.gov (United States)

    Li, Jing; Wu, Xiaoping

    2011-10-10

    In this paper a model of the trapping force on nanowires is built by three dimensional finite-difference time-domain (FDTD) and Maxwell stress tensor methods, and the tightly focused laser beam is expressed by spherical vector wave functions (VSWFs). The trapping capacities on nanoscale-diameter nanowires are discussed in terms of a strongly focused linearly polarized beam and radially polarized beam. Simulation results demonstrate that the radially polarized beam has higher trapping efficiency on nanowires with higher refractive indices than linearly polarized beam.

  10. A novel orthogonally linearly polarized Nd:YVO4 laser

    International Nuclear Information System (INIS)

    Xing-Peng, Yan; Qiang, Liu; Hai-Long, Chen; Xing, Fu; Ma-Li, Gong; Dong-Sheng, Wang

    2010-01-01

    We presented a novel orthogonally linearly polarized Nd:YVO 4 laser. Two pieces of α-cut grown-together composite YVO 4 /Nd:YVO 4 crystals were placed in the resonant cavity with the c-axis of the two crystals orthogonally. The polarization and power performance of the orthogonally polarized laser were investigated. A 26.2-W orthogonally linearly polarized laser was obtained. The power ratio between the two orthogonally polarized lasers was varied with the pump power caused by the polarized mode coupling. The longitudinal modes competition and the corresponding variable optical beats were also observed from the orthogonally polarized laser. We also adjusted the crystals with their c-axis parallele to each other, and a 40.7-W linearly polarized TEM 00 laser was obtained, and the beam quality factors were M x 2 = 1.37 and M y 2 = 1.25. (classical areas of phenomenology)

  11. Polarized electronic sources for future e+/e- linear colliders

    International Nuclear Information System (INIS)

    Tang, H.; Alley, R.K.; Clendenin, J.E.

    1997-05-01

    Polarized electron beams will play a crucial role in maximizing the physics potential for future e + /e - linear colliders. We will review the SLC polarized electron source (PES), present a design for a conventional PES for the Next Linear Collider (NLC), and discuss the physics issues of a polarized RF gun

  12. Acceleration of polarized electrons in the Bonn synchrotron and the planned stretcher ring ELSA. Beschleunigung von polarisierten Elektronen im Bonner Synchrotron und im geplanten Stretcherring ELSA

    Energy Technology Data Exchange (ETDEWEB)

    Brefeld, W.

    1981-10-01

    In the last year at the synchrotron polarized electrons were successfully accelerated. For this the polarization vector in the transfer channel between source and LINAC was rotated in such a way that the electrons can be injected into the accelerator with the necessary vertical polarization. It was shown that the degree of polarization of the electrons after passing of the imperfection resonances at 0.441 GeV, 0.881 GeV, 1.322 GeV, and 1.763 GeV and the intrinsic resonance at 1.498 GeV remained conserved at a high degree also without additional procedures. Although it is desirable to reduce the present depolarization. First attempts for overcoming the second resonance were performed. The results indicate that for this a system of two pulse dipoles doesn't suffice. For the answer of this question however a much more intensive polarized source is needed. At ELSA the working with polarized electrons seems to be possible in the whole energy range if it succeeds to circumvent the position of the intrinsic resonance dependent from the working point. Though the imperfection resonances at 2.203 GeV, 2.644 GeV, and 3.085 GeV can depolarize the electrons much more strongly because of the relatively slow passing through the resonances an overcoming with pulse dipoles should by possible. Because of the large resonance time-distances the dipoles have much more time than in the synchrotron to reach the required value steadily.

  13. Overview and perspective of materials characterization by using synchrotron radiation

    International Nuclear Information System (INIS)

    Kamitsubo, Hiromichi

    2009-01-01

    A peculiarity of techniques and the methods of synchrotron radiation are explained. It consists of five sections such as introduction, synchrotron radiation, interaction between X-ray and materials, analytical methods of materials using synchrotron radiation and perspective and problems. The second section described the principles of synchrotron orbit radiation, synchrotron light source, the main formulae and schematic drawing of undulator, and the synchrotron radiation facilities in Japan. The third section explained behavior of X-ray in materials, absorption, reflection, refraction and scattering of X-ray. The fourth section stated many analytical methods of materials; the surface diffractometer, powder diffractometer, high-energy X-ray diffraction, core-electron absorption spectroscopy, micro-beam diffraction, X-ray fluorescence, X-ray absorption fine structure (XAFS), and photoemission spectroscopy (PES). A characteristic feature of synchrotron radiation contains the large wave length ranges from infrared to X-ray, high directivity and brightness, linear (circular) polarization, pulsed light, good control and stability. The brightness spectra of Spring-8 and SAGA-LS, concept of synchrotron light source, undulator and wiggler, nine synchrotron radiation facilities in Japan, mass absorption coefficients of Cu and Au, and analysis of materials using synchrotron radiation are illustrated. (S.Y.)

  14. 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.

  15. 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

  16. Linear polarizers based on oriented polymer blends

    NARCIS (Netherlands)

    Jagt, H.J.B.; Dirix, Y.J.L.; Hikmet, R.A.M.; Bastiaansen, C.W.M.

    1998-01-01

    Linear sheet polarizers based on the anisotropic scattering of light by drawn polymer blends are introduced here. The proper selection of materials and processing conditions for the production of large-area, flexible films of phase-segregated polymer blends suitable for polarization applications are

  17. Synchrotron radiation

    CERN Document Server

    Kunz, C

    1974-01-01

    The production of synchrotron radiation as a by-product of circular high-energy electron (positron) accelerators or storage rings is briefly discussed. A listing of existing or planned synchrotron radiation laboratories is included. The following properties are discussed: spectrum, collimation, polarization, and intensity; a short comparison with other sources (lasers and X-ray tubes) is also given. The remainder of the paper describes the experimental installations at the Deutsches Elektronen-Synchrotron (DESY) and DORIS storage rings, presents a few typical examples out of the fields of atomic, molecular, and solid-state spectroscopy, and finishes with an outlook on the use of synchrotron radiation in molecular biology. (21 refs).

  18. A guide to using the BL-6A2 synchrotron facilities at the photon factory, Tsukuba, Japan

    International Nuclear Information System (INIS)

    1992-08-01

    The Photon Factory (PF) consists of a 2.5 GeV electron/positron linear accelerator, a 2.5 GeV storage ring as a dedicated synchrotron light source, beam lines and experimental stations, to serve users synchrotron radiation (SR) for experiment. The 2.5 GeV linear accelerator is used as an injector for both PF ring and the accumulating ring (AR). It is currently capable of injecting positrons or electrons. The AR has been partly used as a high energy synchrotron radiation source from its bending magnets, and partly augmented with a new insertion device to produce elliptically polarized radiation. It has been operated for the users of synchrotron radiation at the energy from 5.8 to 6.5 GeV. With the electron beam in the storage ring for SR research, the instability of the beam is inevitable arising from ions or charged dust trapped by the beam. Therefore, positrons are used instead of electrons in order to completely overcome the difficulty. The wiggler produces vertically polarized radiation in the range of photon energy. The superconducting NbTi is well suitable to obtain high magnetic field. (K.I.)

  19. Radio galaxies radiation transfer, dynamics, stability and evolution of a synchrotron plasmon

    CERN Document Server

    Pacholczyk, A G

    1977-01-01

    Radio Galaxies: Radiation Transfer, Dynamics, Stability and Evolution of a Synchrotron Plasmon deals with the physics of a region in space containing magnetic field and thermal and relativistic particles (a plasmon). The synchrotron emission and absorption of this region are discussed, along with the properties of its spectrum; its linear and circular polarization; transfer of radiation through such a region; its dynamics and expansion; and interaction with external medium.Comprised of eight chapters, this volume explores the stability, turbulence, and acceleration of particles in a synchrotro

  20. Direct Probes of Linearly Polarized Gluons inside Unpolarized Hadrons

    NARCIS (Netherlands)

    Boer, D.; Brodsky, S. J.; Mulders, P.J.G.; Pisano, C.

    2011-01-01

    We show that linearly polarized gluons inside unpolarized hadrons can be directly probed in jet or heavy quark pair production in electron-hadron collisions. We discuss the simplest cos2 asymmetries and estimate their maximal value, concluding that measurements of the unknown linearly polarized

  1. Spin dynamics in electron synchrotrons

    International Nuclear Information System (INIS)

    Schmidt, Jan Felix

    2017-01-01

    Providing spin polarized particle beams with circular accelerators requires the consideration of depolarizing resonances which may significantly reduce the desired degree of polarization at specific beam energies. The corresponding spin dynamical effects are typically analyzed with numerical methods. In case of electron beams the influence of the emission of synchrotron radiation has to be taken into account. On short timescales, as in synchrotrons with a fast energy ramp or in damping rings, spin dynamics are investigated with spin tracking algorithms. This thesis presents the spin tracking code Polematrix as a versatile tool to study the impact of synchrotron radiation on spin dynamics. Spin tracking simulations have been performed based on the well established particle tracking code Elegant. The numerical studies demonstrate effects which are responsible for beam depolarization: Synchrotron side bands of depolarizing resonances and decoherence of spin precession. Polematrix can be utilized for any electron accelerator with minimal effort as it imports lattice files from the tracking programs MAD-X or Elegant. Polematrix has been published as open source software. Currently, the Electron Stretcher Accelerator ELSA at Bonn University is the only electron synchrotron worldwide providing a polarized beam. Integer and intrinsic depolarizing resonances are compensated with dedicated countermeasures during the fast energy ramp. Polarization measurements from ELSA demonstrate the particular spin dynamics of electrons and confirm the results of the spin tracking code Polematrix.

  2. Synchrotron Radiation Linear Dichroism (SRLD) and Time Dependent Density Functional Theory (TD-DFT) Calculations on Dihydroxy-Anthraquinones

    DEFF Research Database (Denmark)

    Nguyen, Duy Duc; Spanget-Larsen, Jens

    SRLD spectra of Quinizarin, Anthrarufin, and Chrysazin partially aligned in stretched polyethylene were measured at the ASTRID synchrotron UV1 beamline (ISA, Aarhus University), yielding absorbance and polarization data up to 57000 cm-1. The observed absorption bands were assigned to electronic t...

  3. Measurement of the Asymmetry of Photoproduction of π- Mesons on Linearly Polarized Deuterons by Linearly Polarized Photons

    Science.gov (United States)

    Gauzshtein, V. V.; Zevakov, S. A.; Levchuk, M. I.; Loginov, A. Yu.; Nikolenko, D. M.; Rachek, I. A.; Sadykov, R. Sh.; Toporkov, D. K.; Shestakov, Yu. V.

    2018-05-01

    The first results of a double polarization experiment to extract the asymmetry of the reaction of photoproduction of a π- meson by a linearly polarized photon on a tensor-polarized deuteron in the energy range of the virtual photon (300-700 MeV) are presented. The measurements were performed on an internal tensor-polarized deuterium target in the VEPP-3 electron-positron storage ring for the electron beam energy equal to 2 GeV. The experiment employed the method of recording two protons and the scattered electron in coincidence. The obtained measurement results are compared with the theoretical predictions obtained in the momentum approximation with allowance for πN and NN rescattering in the final state.

  4. Significant and variable linear polarization during the prompt optical flash of GRB 160625B.

    Science.gov (United States)

    Troja, E.; Lipunov, V. M.; Mundell, C. G.; Butler, N. R.; Watson, A. M.; Kobayashi, S.; Cenko, S. B.; Marshall, F. E.; Ricci, R.; Fruchter, A.; Wieringa, M. H.; Gorbovskoy, E. S.; Kornilov, V.; Kutyrev, A.; Lee, W. H.; Toy, V.; Tyurina, N. V.; Budnev, N. M.; Buckley, D. A. H.; González, J.; Gress, O.; Horesh, A.; Panasyuk, M. I.; Prochaska, J. X.; Ramirez-Ruiz, E.; Rebolo Lopez, R.; Richer, M. G.; Roman-Zuniga, C.; Serra-Ricart, M.; Yurkov, V.; Gehrels, N.

    2017-07-01

    Newly formed black holes of stellar mass launch collimated outflows (jets) of ionized matter that approach the speed of light. These outflows power prompt, brief and intense flashes of γ-rays known as γ-ray bursts (GRBs), followed by longer-lived afterglow radiation that is detected across the electromagnetic spectrum. Measuring the polarization of the observed GRB radiation provides a direct probe of the magnetic fields in the collimated jets. Rapid-response polarimetric observations of newly discovered bursts have probed the initial afterglow phase, and show that, minutes after the prompt emission has ended, the degree of linear polarization can be as high as 30 per cent - consistent with the idea that a stable, globally ordered magnetic field permeates the jet at large distances from the central source. By contrast, optical and γ-ray observations during the prompt phase have led to discordant and often controversial results, and no definitive conclusions have been reached regarding the origin of the prompt radiation or the configuration of the magnetic field. Here we report the detection of substantial (8.3 ± 0.8 per cent from our most conservative simulation), variable linear polarization of a prompt optical flash that accompanied the extremely energetic and long-lived prompt γ-ray emission from GRB 160625B. Our measurements probe the structure of the magnetic field at an early stage of the jet, closer to its central black hole, and show that the prompt phase is produced via fast-cooling synchrotron radiation in a large-scale magnetic field that is advected from the black hole and distorted by dissipation processes within the jet.

  5. Linear polarization-discriminatory state inverter fabricated by oblique angle deposition.

    Science.gov (United States)

    Park, Yong Jun; Sobahan, K M A; Kim, Jin Joo; Hwangbo, Chang Kwon

    2009-06-22

    In this paper, we report a linear polarization-discriminatory state inverter made of three-layer sculpture thin film fabricated by oblique angle deposition technique. The first and third layers are quarter-wave plates of zigzag structure and the middle of them is a circular Bragg reflector of left-handed helical structure. It is found that the normal incidence of P-polarized light on this polarization-discriminatory state inverter becomes the S-polarized light at output, while the incident S-polarized light of wavelength lying in the Bragg regime is reflected. The microstructure of the linear polarization-discriminatory state inverter is also investigated by using a scanning electron microscope.

  6. Linear Polarization Properties of Parsec-Scale AGN Jets

    Directory of Open Access Journals (Sweden)

    Alexander B. Pushkarev

    2017-12-01

    Full Text Available We used 15 GHz multi-epoch Very Long Baseline Array (VLBA polarization sensitive observations of 484 sources within a time interval 1996–2016 from the MOJAVE program, and also from the NRAO data archive. We have analyzed the linear polarization characteristics of the compact core features and regions downstream, and their changes along and across the parsec-scale active galactic nuclei (AGN jets. We detected a significant increase of fractional polarization with distance from the radio core along the jet as well as towards the jet edges. Compared to quasars, BL Lacs have a higher degree of polarization and exhibit more stable electric vector position angles (EVPAs in their core features and a better alignment of the EVPAs with the local jet direction. The latter is accompanied by a higher degree of linear polarization, suggesting that compact bright jet features might be strong transverse shocks, which enhance magnetic field regularity by compression.

  7. 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.

  8. Photon-ion spectrometer PIPE at the Variable Polarization XUV Beamline of PETRA III

    International Nuclear Information System (INIS)

    Schippers, S; Ricz, S; Buhr, T; Hellhund, J; Müller, A; Klumpp, S; Martins, M; Flesch, R; Rühl, E; Lower, J; Jahnke, T; Metz, D; Schmidt, L Ph H; Dörner, R; Ullrich, J; Wolf, A

    2012-01-01

    The photon-ion spectrometer PIPE is currently being installed as a permanent end station at beamline P04 of the PETRA III synchrotron radiation source. Various state-of-the-art experimental techniques will be available for studies of gaseous matter with circularly and linearly polarized synchrotron radiation with photon energies in range the 100–3000 eV.

  9. Testing the existence of optical linear polarization in young brown dwarfs

    Science.gov (United States)

    Manjavacas, E.; Miles-Páez, P. A.; Zapatero-Osorio, M. R.; Goldman, B.; Buenzli, E.; Henning, T.; Pallé, E.; Fang, M.

    2017-07-01

    Linear polarization can be used as a probe of the existence of atmospheric condensates in ultracool dwarfs. Models predict that the observed linear polarization increases with the degree of oblateness, which is inversely proportional to the surface gravity. We aimed to test the existence of optical linear polarization in a sample of bright young brown dwarfs, with spectral types between M6 and L2, observable from the Calar Alto Observatory, and cataloged previously as low gravity objects using spectroscopy. Linear polarimetric images were collected in I and R band using CAFOS at the 2.2-m telescope in Calar Alto Observatory (Spain). The flux ratio method was employed to determine the linear polarization degrees. With a confidence of 3σ, our data indicate that all targets have a linear polarimetry degree in average below 0.69 per cent in the I band, and below 1.0 per cent in the R band, at the time they were observed. We detected significant (I.e. P/σ ≥ 3) linear polarization for the young M6 dwarf 2MASS J04221413+1530525 in the R band, with a degree of p* = 0.81 ± 0.17 per cent.

  10. Advances in high power linearly polarized fiber laser and its application

    Science.gov (United States)

    Zhou, Pu; Huang, Long; Ma, Pengfei; Xu, Jiangming; Su, Rongtao; Wang, Xiaolin

    2017-10-01

    Fiber lasers are now attracting more and more research interest due to their advantages in efficiency, beam quality and flexible operation. Up to now, most of the high power fiber lasers have random distributed polarization state. Linearlypolarized (LP) fiber lasers, which could find wide application potential in coherent detection, coherent/spectral beam combining, nonlinear frequency conversion, have been a research focus in recent years. In this paper, we will present a general review on the achievements of various kinds of high power linear-polarized fiber laser and its application. The recent progress in our group, including power scaling by using power amplifier with different mechanism, high power linearly polarized fiber laser with diversified properties, and various applications of high power linear-polarized fiber laser, are summarized. We have achieved 100 Watt level random distributed feedback fiber laser, kilowatt level continuous-wave (CW) all-fiber polarization-maintained fiber amplifier, 600 watt level average power picosecond polarization-maintained fiber amplifier and 300 watt level average power femtosecond polarization-maintained fiber amplifier. In addition, high power linearly polarized fiber lasers have been successfully applied in 5 kilowatt level coherent beam combining, structured light field and ultrasonic generation.

  11. Accessing the distribution of linearly polarized gluons in unpolarized hadrons

    NARCIS (Netherlands)

    Boer, Daniël; Brodsky, Stanley J.; Mulders, Piet J.; Pisano, Cristian

    2011-01-01

    Gluons inside unpolarized hadrons can be linearly polarized provided they have a nonzero transverse momentum. The simplest and theoretically safest way to probe this distribution of linearly polarized gluons is through cos(2 phi) asymmetries in heavy quark pair or dijet production in electron-hadron

  12. Turbulence in extended synchrotron radio sources. I. Polarization of turbulent sources. II. Power-spectral analysis

    International Nuclear Information System (INIS)

    Eilek, J.A.

    1989-01-01

    Recent theories of magnetohydrodynamic turbulence are used to construct microphysical turbulence models, with emphasis on models of anisotropic turbulence. These models have been applied to the determination of the emergent polarization from a resolved uniform source. It is found that depolarization alone is not a unique measure of the turbulence, and that the turblence will also affect the total-intensity distributions. Fluctuations in the intensity image can thus be employed to measure turbulence strength. In the second part, it is demonstrated that a power-spectral analysis of the total and polarized intensity images can be used to obtain the power spectra of the synchrotron emission. 81 refs

  13. Non-polar InGaN quantum dot emission with crystal-axis oriented linear polarization

    Energy Technology Data Exchange (ETDEWEB)

    Reid, Benjamin P. L., E-mail: benjamin.reid@physics.ox.ac.uk; Chan, Christopher C. S.; Taylor, Robert A. [Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU (United Kingdom); Kocher, Claudius [Department of Physics, University of Konstanz, Konstanz 78457 (Germany); Zhu, Tongtong; Oehler, Fabrice; Oliver, Rachel A. [Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS (United Kingdom)

    2015-04-27

    Polarization sensitive photoluminescence is performed on single non-polar InGaN quantum dots. The studied InGaN quantum dots are found to have linearly polarized emission with a common polarization direction defined by the [0001] crystal axis. Around half of ∼40 studied dots have a polarization degree of 1. For those lines with a polarization degree less than 1, we can resolve fine structure splittings between −800 μeV and +800 μeV, with no clear correlation between fine structure splitting and emission energy.

  14. Polarized wiggler for NSLS x-ray ring design considerations

    International Nuclear Information System (INIS)

    Friedman, A.; Krinsky, S.; Blum, E.

    1992-03-01

    We examine the properties of an elliptically polarized wiggler that will generate circularly polarized photons with energy spectrum of 3--12 KeV. The vertical wiggler magnetic field is produced by permanent magnets while the horizontal wiggler field is generated by electric coils capable of AC excitation. The radiation parameters of the wiggler are presented, including photon flux, circular and linear polarization and spectrum. These parameters are compared to the synchrotron radiation from a bending magnet. Numerical values are calculated for radiation from the wiggler and bending magnet for the NSLS X-ray ring parameters. A conceptual design for such a wiggler is discussed and several different alternatives are analyzed. We consider AC excitation of the wiggler to produce the time modulation of the elliptic polarization, and also to produce time modulated linearly polarized radiation

  15. Proton polarization in the photodisintegration of the deuteron by linearly polarized 400- and 500-MeV γ rays

    International Nuclear Information System (INIS)

    Bratashevskii, A.S.; Gorbenko, V.G.; Gushchin, V.A.

    1982-01-01

    The polarization of the recoil protons at the angle theta(/sub p/ = 90 0 has been measured in the photodisintegration of the deuteron by linearly polarized 400- and 500-MeV γ rays. For the first time, all of the following observables have been determined under identical experimental conditions: Σ, the asymmetry of the cross sections; P/sub y/, the polarization of the recoil proton; and T 1 , the asymmetry of the nucleon polarization for the case of linearly polarized γ rays

  16. Linear polarization observations of some X-ray sources

    International Nuclear Information System (INIS)

    Shakhovskoy, N.M.; Efimov, Yu.S.

    1975-01-01

    Multicolour linear polarization of optical radiation of the X-ray sources Sco X-1, Cyg X-2, Cyg X-1 and Her X-1 was measured at the Crimean Astrophysical Observatory in 1970-1973. These observations indicate that polarization of Sco X-1 in the ultraviolet, blue and red spectral regions appears to be variable. No statistically significant variations of polarization were found for the other three sources observed. (Auth.)

  17. Polarized e-e+ physics in linear colliders

    International Nuclear Information System (INIS)

    Prescott, C.Y.

    1980-11-01

    Electroweak interactions at high energies are expected to be dominated by spin-dependent forces. Recent advances in the production of polarized electron beams in linear machines provide the opportunity for studying these spin-dependent effects. Polarized e - e + annihilation at the Z 0 pole can provide precise measurements of neutral current parameters and the best experimental challenge to the standard model of electroweak interactions

  18. NEAR-INFRARED LINEAR POLARIZATION OF ULTRACOOL DWARFS

    International Nuclear Information System (INIS)

    Zapatero Osorio, M. R.; Bejar, V. J. S.; Rebolo, R.; Acosta-Pulido, J. A.; Manchado, A.; Pena Ramirez, K.; Goldman, B.; Caballero, J. A.

    2011-01-01

    We report on near-infrared J- and H-band linear polarimetric photometry of eight ultracool dwarfs (two late-M, five L0-L7.5, and one T2.5) with known evidence for photometric variability due to dust clouds, anomalous red infrared colors, or low-gravity atmospheres. The polarimetric data were acquired with the LIRIS instrument on the William Herschel Telescope. We also provide mid-infrared photometry in the interval 3.4-24 μm for some targets obtained with Spitzer and WISE, which has allowed us to confirm the peculiar red colors of five sources in the sample. We can impose modest upper limits of 0.9% and 1.8% on the linear polarization degree for seven targets with a confidence of 99%. Only one source, 2MASS J02411151-0326587 (L0), appears to be strongly polarized (P ∼ 3%) in the J band with a significance level of P/σ P ∼ 10. The likely origin of its linearly polarized light and rather red infrared colors may reside in a surrounding disk with an asymmetric distribution of grains. Given its proximity (66 ± 8 pc), this object becomes an excellent target for the direct detection of the disk.

  19. Linear polarized fluctuations in the cosmic microwave background

    International Nuclear Information System (INIS)

    Partridge, R.B.; Nowakowski, J.; Martin, H.M.

    1988-01-01

    We report here limits on the linear (and circular) polarization of the cosmic microwave background on small angular scales, 18''≤ θ ≤ 160''. The limits are based on radio maps of Stokes parameters and polarisation (linear and circular). (author)

  20. Polarization dependent effects in photo-fragmentation dynamics of free molecules

    International Nuclear Information System (INIS)

    Mocellin, A.; Marinho, R.R.T.; Coutinho, L.H.; Burmeister, F.; Wiesner, K.; Naves de Brito, A.

    2003-01-01

    We present multicoincidence spectra of nitrogen, formic acid and methyl methacrylate. We demonstrate how to probe the local symmetry of molecular orbitals from molecules core excited with linearly polarized synchrotron radiation. The intensity distribution of the photoelectron photo-ion photo-ion coincidence (PEPIPICO) spectrum reflects the selectivity and localization of core excitation by polarized light. By simulating the spectra the angular dependence of the fragmentation is determined

  1. Polarization dependent effects in photo-fragmentation dynamics of free molecules

    Energy Technology Data Exchange (ETDEWEB)

    Mocellin, A.; Marinho, R.R.T.; Coutinho, L.H.; Burmeister, F.; Wiesner, K.; Naves de Brito, A

    2003-04-01

    We present multicoincidence spectra of nitrogen, formic acid and methyl methacrylate. We demonstrate how to probe the local symmetry of molecular orbitals from molecules core excited with linearly polarized synchrotron radiation. The intensity distribution of the photoelectron photo-ion photo-ion coincidence (PEPIPICO) spectrum reflects the selectivity and localization of core excitation by polarized light. By simulating the spectra the angular dependence of the fragmentation is determined.

  2. LINEARLY POLARIZED PROBES OF SURFACE CHIRALITY

    NARCIS (Netherlands)

    VERBIEST, T; KAURANEN, M; MAKI, JJ; TEERENSTRA, MN; SCHOUTEN, AJ; NOLTE, RJM; PERSOONS, A

    1995-01-01

    We present a new nonlinear optical technique to study surface chirality. We demonstrate experimentally that the efficiency of second-harmonic generation from isotropic chiral surfaces is different for excitation with fundamental light that is +45 degrees and -45 degrees linearly polarized with

  3. Vacuum system of Synchrotron Light National Laboratory (LNLS) linear accelerator: project and results

    International Nuclear Information System (INIS)

    Rocha, L.R.B.; Gomes, P.A.P.

    1990-01-01

    The LINAC, electron linear accelerator used as injector for storage ring in production of synchrotron radiation at Laboratorio Nacional de Luz Sincrotron (LNLS) is described. The LINAC basic parameters, the dimension calculations of vacuum system and the final project with all components are presented. The vacuum system for electron gun tests and accelerator structure tests is described. (M.C.K.)

  4. 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.

  5. Production of linear polarization by segmentation of helical undulator

    International Nuclear Information System (INIS)

    Tanaka, T.; Kitamura, H.

    2002-01-01

    A simple scheme to obtain linearly polarized radiation (LPR) with a segmented undulator is proposed. The undulator is composed of several segments each of which forms a helical undulator and has helicity opposite to those of adjacent segments. Due to coherent sum of radiation, the circularly polarized component is canceled out resulting in production of LPR without any higher harmonics. The radiation from the proposed device is investigated analytically, which shows that a high degree of linear polarization is obtained in spite of a finite beam emittance and angular acceptance of optics, if a sufficiently large number of segments and an adequate photon energy are chosen. Results of calculation to investigate practical performances of the proposed device are presented

  6. Measurement of neutron spectra for photonuclear reaction with linearly polarized photons

    Directory of Open Access Journals (Sweden)

    Kirihara Yoichi

    2017-01-01

    Full Text Available Spectra of neutrons produced by a photonuclear reaction from a 197Au target were measured using 16.95 MeV linearly and circularly polarized photon beams at NewSUBARU-BL01 using a time-of-flight method. The difference in the neutron spectra between the cases of a linearly and circularly polarized photon was measured. The difference in the neutron yield increased with the neutron energy and was approximately threefold at the maximum neutron energy. In a direction perpendicular to that of the linear polarization, the neutron yields decreased as the neutron energy increased.

  7. Shielded coherent synchrotron radiation and its possible effect in the next linear collider

    International Nuclear Information System (INIS)

    Warnock, R.L.

    1991-05-01

    Shielded coherent synchrotron radiation is discussed in two cases: (1) a beam following a curved path in a plane midway between two parallel, perfectly conducting plates, and (2) a beam circulating in a toroidal chamber with resistive walls. Wake fields and the radiated energy are computed with parameters for the high-energy bunch compressor of the Next Linear Collider. 5 refs., 4 figs., 1 tab

  8. Inducing elliptically polarized high-order harmonics from aligned molecules with linearly polarized femtosecond pulses

    DEFF Research Database (Denmark)

    Etches, Adam; Madsen, Christian Bruun; Madsen, Lars Bojer

    2010-01-01

    A recent paper reported elliptically polarized high-order harmonics from aligned N2 using a linearly polarized driving field [X. Zhou et al., Phys. Rev. Lett. 102, 073902 (2009)]. This observation cannot be explained in the standard treatment of the Lewenstein model and has been ascribed to many...

  9. McDONALD OBSERVATORY ARCHIVE OF OPTICAL LINEAR POLARIZATION MEASUREMENTS

    International Nuclear Information System (INIS)

    Wills, Beverley J.; Wills, D.; Breger, M.

    2011-01-01

    We present 990 previously unpublished optical linear polarization measurements of quasars, active galactic nuclei, and some stars observed for interstellar polarization. The observations, covering the period 1981-2000, were made with McDonald Observatory's 2.1 m Struve reflector and the Breger photopolarimeter.

  10. Characterization of a microfocused circularly polarized x-ray probe

    International Nuclear Information System (INIS)

    Pollmann, J.; Srajer, G.; Maser, J.; Lang, J. C.; Nelson, C. S.; Venkataraman, C. T.; Isaacs, E. D.

    2000-01-01

    We report on the development of a circularly polarized x-ray microprobe in the intermediate energy range from 5 to 10 keV. In this experiment linearly polarized synchrotron radiation was circularly polarized by means of a Bragg-diffracting diamond phase retarder and subsequently focused down to a spot size of about 4x2 μm 2 by a Fresnel zone plate. The properties of the microprobe were characterized, and the technique was applied to the two-dimensional mapping of magnetic domains in HoFe 2 . (c) 2000 American Institute of Physics

  11. Linearly polarized emission from an embedded quantum dot using nanowire morphology control.

    Science.gov (United States)

    Foster, Andrew P; Bradley, John P; Gardner, Kirsty; Krysa, Andrey B; Royall, Ben; Skolnick, Maurice S; Wilson, Luke R

    2015-03-11

    GaAs nanowires with elongated cross sections are formed using a catalyst-free growth technique. This is achieved by patterning elongated nanoscale openings within a silicon dioxide growth mask on a (111)B GaAs substrate. It is observed that MOVPE-grown vertical nanowires with cross section elongated in the [21̅1̅] and [1̅12] directions remain faithful to the geometry of the openings. An InGaAs quantum dot with weak radial confinement is realized within each nanowire by briefly introducing indium into the reactor during nanowire growth. Photoluminescence emission from an embedded nanowire quantum dot is strongly linearly polarized (typically >90%) with the polarization direction coincident with the axis of elongation. Linearly polarized PL emission is a result of embedding the quantum dot in an anisotropic nanowire structure that supports a single strongly confined, linearly polarized optical mode. This research provides a route to the bottom-up growth of linearly polarized single photon sources of interest for quantum information applications.

  12. Beamline 9.3.2 - a high-resolution, bend-magnet beamline with circular polarization capability

    Energy Technology Data Exchange (ETDEWEB)

    Moler, E.J.; Hussain, Z.; Howells, M.R. [Lawrence Berkeley National Lab., CA (United States)] [and others

    1997-04-01

    Beamline 9.3.2 is a high resolution, SGM beamline on an ALS bending magnet with access to photon energies from 30-1500 eV. Features include circular polarization capability, a rotating chamber platform that allows switching between experiments without breaking vacuum, an active feedback system that keeps the beam centered on the entrance slit of the monochromator, and a bendable refocusing mirror. The beamline optics consist of horizontally and vertically focussing mirrors, a Spherical Grating Monochromator (SGM) with movable entrance and exit slits, and a bendable refocussing mirror. In addition, a movable aperature has been installed just upstream of the vertically focussing mirror which can select the x-rays above or below the plane of the synchrotron storage ring, allowing the user to select circularly or linearly polarized light. Circularly polarized x-rays are used to study the magnetic properties of materials. Beamline 9.3.2 can supply left and right circularly polarized x-rays by a computer controlled aperture which may be placed above or below the plane of the synchrotron storage ring. The degree of linear and circular polarization has been measured and calibrated.

  13. Full-Stokes polarimetry with circularly polarized feeds. Sources with stable linear and circular polarization in the GHz regime

    Science.gov (United States)

    Myserlis, I.; Angelakis, E.; Kraus, A.; Liontas, C. A.; Marchili, N.; Aller, M. F.; Aller, H. D.; Karamanavis, V.; Fuhrmann, L.; Krichbaum, T. P.; Zensus, J. A.

    2018-01-01

    We present an analysis pipeline that enables the recovery of reliable information for all four Stokes parameters with high accuracy. Its novelty relies on the effective treatment of the instrumental effects even before the computation of the Stokes parameters, contrary to conventionally used methods such as that based on the Müller matrix. For instance, instrumental linear polarization is corrected across the whole telescope beam and significant Stokes Q and U can be recovered even when the recorded signals are severely corrupted by instrumental effects. The accuracy we reach in terms of polarization degree is of the order of 0.1-0.2%. The polarization angles are determined with an accuracy of almost 1°. The presented methodology was applied to recover the linear and circular polarization of around 150 active galactic nuclei, which were monitored between July 2010 and April 2016 with the Effelsberg 100-m telescope at 4.85 GHz and 8.35 GHz with a median cadence of 1.2 months. The polarized emission of the Moon was used to calibrate the polarization angle measurements. Our analysis showed a small system-induced rotation of about 1° at both observing frequencies. Over the examined period, five sources have significant and stable linear polarization; three sources remain constantly linearly unpolarized; and a total of 11 sources have stable circular polarization degree mc, four of them with non-zero mc. We also identify eight sources that maintain a stable polarization angle. All this is provided to the community for future polarization observations reference. We finally show that our analysis method is conceptually different from those traditionally used and performs better than the Müller matrix method. Although it has been developed for a system equipped with circularly polarized feeds, it can easily be generalized to systems with linearly polarized feeds as well. The data used to create Fig. C.1 are only available at the CDS via anonymous ftp to http

  14. Investigating circular patterns in linear polarization observations of Venus

    NARCIS (Netherlands)

    Mahapatra, G.; Stam, D.M.; Rossi, L.C.G.; Rodenhuis, M.; Snik, Frans; Keller, C.U.

    2017-01-01

    In this work, we analyse linear polarization data of the planet at a distance, obtained with the Extreme Polarimeter (ExPo) on the William Herschel Telescope
    on La Palma. These spatially resolved, high-accuracy polarization observations of Venus show faint circular patterns centered on the

  15. Spin dynamics in electron synchrotrons; Spindynamik in Elektronensynchrotronen

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Jan Felix

    2017-07-14

    Providing spin polarized particle beams with circular accelerators requires the consideration of depolarizing resonances which may significantly reduce the desired degree of polarization at specific beam energies. The corresponding spin dynamical effects are typically analyzed with numerical methods. In case of electron beams the influence of the emission of synchrotron radiation has to be taken into account. On short timescales, as in synchrotrons with a fast energy ramp or in damping rings, spin dynamics are investigated with spin tracking algorithms. This thesis presents the spin tracking code Polematrix as a versatile tool to study the impact of synchrotron radiation on spin dynamics. Spin tracking simulations have been performed based on the well established particle tracking code Elegant. The numerical studies demonstrate effects which are responsible for beam depolarization: Synchrotron side bands of depolarizing resonances and decoherence of spin precession. Polematrix can be utilized for any electron accelerator with minimal effort as it imports lattice files from the tracking programs MAD-X or Elegant. Polematrix has been published as open source software. Currently, the Electron Stretcher Accelerator ELSA at Bonn University is the only electron synchrotron worldwide providing a polarized beam. Integer and intrinsic depolarizing resonances are compensated with dedicated countermeasures during the fast energy ramp. Polarization measurements from ELSA demonstrate the particular spin dynamics of electrons and confirm the results of the spin tracking code Polematrix.

  16. Synchrotron-based far-infrared spectroscopy of nickel tungstate

    International Nuclear Information System (INIS)

    Kalinko, A.; Kuzmin, A.; Roy, P.; Evarestov, R.A.

    2016-01-01

    Monoclinic antiferromagnetic NiWO 4 was studied by far-infrared (30-600 cm -1 ) absorption spectroscopy in the temperature range of 5-300 K using the synchrotron radiation from SOLEIL source. Two isomorphous CoWO 4 and ZnWO 4 tungstates were investigated for comparison. The phonon contributions in the far-infrared range of tungstates were interpreted using the first-principles spin-polarized linear combination of atomic orbital calculations. No contributions from magnetic excitations were found in NiWO 4 and CoWO 4 below their Neel temperatures down to 5 K.

  17. LINEAR POLARIZATION OF CLASS I METHANOL MASERS IN MASSIVE STAR-FORMING REGIONS

    International Nuclear Information System (INIS)

    Kang, Ji-hyun; Byun, Do-Young; Kim, Kee-Tae; Kim, Jongsoo; Lyo, A-Ran; Vlemmings, W. H. T.

    2016-01-01

    Class I methanol masers are found to be good tracers of the interaction between outflows from massive young stellar objects with their surrounding media. Although polarization observations of Class II methanol masers have been able to provide information about magnetic fields close to the central (proto)stars, polarization observations of Class I methanol masers are rare, especially at 44 and 95 GHz. We present the results of linear polarization observations of 39 Class I methanol maser sources at 44 and 95 GHz. These two lines are observed simultaneously with one of the 21 m Korean VLBI Network telescopes in single-dish mode. Approximately 60% of the observed sources have fractional polarizations of a few percent in at least one transition. This is the first reported detection of linear polarization of the 44 GHz methanol maser. The two maser transitions show similar polarization properties, indicating that they trace similar magnetic environments, although the fraction of the linear polarization is slightly higher at 95 GHz. We discuss the association between the directions of polarization angles and outflows. We also discuss some targets having different polarization properties at both lines, including DR21(OH) and G82.58+0.20, which show the 90° polarization angle flip at 44 GHz.

  18. A linear polarization converter with near unity efficiency in microwave regime

    Science.gov (United States)

    Xu, Peng; Wang, Shen-Yun; Geyi, Wen

    2017-04-01

    In this paper, we present a linear polarization converter in the reflective mode with near unity conversion efficiency. The converter is designed in an array form on the basis of a pair of orthogonally arranged three-dimensional split-loop resonators sharing a common terminal coaxial port and a continuous metallic ground slab. It converts the linearly polarized incident electromagnetic wave at resonance to its orthogonal counterpart upon the reflection mode. The conversion mechanism is explained by an equivalent circuit model, and the conversion efficiency can be tuned by changing the impedance of the terminal port. Such a scheme of the linear polarization converter has potential applications in microwave communications, remote sensing, and imaging.

  19. Moessbauer spectroscopy with synchrotron radiation

    International Nuclear Information System (INIS)

    Bergmann, U.

    1994-01-01

    The short pulse nature of synchrotron radiation makes it possible to perform Moessbauer spectroscopy in the time domain, i.e. instead of measuring the transmitted intensity time integrated as a function of source/absorber velocity, the intensity of the scattered radiation is measured time differential. The resulting time spectrum is essentially source independent and complications in the data analysis which are related to the radioactive source are completely removed. Furthermore, the large brightness and well defined polarization of the synchrotron radiation can, e.g., speed up the data collection and facilitate studies of polarization phenomena. To illustrate these new spectroscopic possibilities, measurements of the temperature dependence and polarization dependence of forward scattering from alpha - sup 5 sup 7 Fe nuclei are presented and discussed 26 refs., 5 figs. (author)

  20. SDP_mharwit_1: Demonstration of HIFI Linear Polarization Analysis of Spectral Features

    Science.gov (United States)

    Harwit, M.

    2010-03-01

    We propose to observe the polarization of the 621 GHz water vapor maser in VY Canis Majoris to demonstrate the capability of HIFI to make polarization observations of Far-Infrared/Submillimeter spectral lines. The proposed Demonstration Phase would: - Show that HIFI is capable of interesting linear polarization measurements of spectral lines; - Test out the highest spectral resolving power to sort out closely spaced Doppler components; - Determine whether the relative intensities predicted by Neufeld and Melnick are correct; - Record the degree and direction of linear polarization for the closely-Doppler shifted peaks.

  1. Development of polarized e+ beams for future linear colliders

    International Nuclear Information System (INIS)

    Chiba, M.; Hamatsu, R.; Endo, A.

    1995-01-01

    We have so far been carrying out systematic investigations to create polarized e + on the basis of two new methods. One method is to use β + decay of radioactive nuclei with short life-time produced with a proton cyclotron and the other method is to use e + e - pair creation from polarized γ beams made through backward Compton scattering of laser lights. Here we describe technical details on productions of polarized e + and measurements of the polarization. The experiments of producing polarized e + will soon start. Although the e + intensity is not sufficiently high, we will acquire lots of know-how for further development of polarized e + sources with high quality which will possibly be applied to future linear colliders. (author)

  2. Design Concept of Superconducting Multipole Wiggler with Variably Polarized X-Ray

    International Nuclear Information System (INIS)

    Hwang, C.S.; Chang, C.H.; Li, W.P.; Lin, F.Y.

    2004-01-01

    In response to the growing demand for X-ray research, and to satisfy future needs for generating circularly polarized synchrotron radiation in the X-ray region, a 3.5 T superconducting multipole with a periodic length of 6 cm was designed to produce horizontal linearly polarized, and circularly polarized light on a 1.5 GeV electron storage ring. Differently arranged excitation current loop for the same coil design switched between the operation of symmetric and asymmetric modes to creat the linearly and circularly polarized light, respectively. This study elucidates the design concepts of the superconducting multipole wiggler with symmetric and asymmetric operation modes. The design of the magnetic circuit and the field calculation are also discussed. Meanwhile, the spectra characteristics of the symmetric and asymmetric modes are calculated and presented in this article

  3. Dual-band linearly and circularly polarized microstrip patch antennas with meandering slot and metallic vias

    DEFF Research Database (Denmark)

    Zhang, Jin; Lin, Xianqi; Yu, Jiawei

    2018-01-01

    performances. The characteristics are analyzed in detail where we find that the existence of the vias also improves the impedance matching. Four samples are designed, where dual-band with both linear polarization, dual-band with circular- and linear-polarization, and single band with linear polarization...

  4. Linear Transformation of the Polarization Modes in Coiled Optical Spun-Fibers with Strong Unperturbed Linear Birefringence. I. Nonresonant Transformation

    Science.gov (United States)

    Malykin, G. B.; Pozdnyakova, V. I.

    2018-03-01

    A linear transformation of orthogonal polarization modes in coiled optical spun-fibers with strong unperturbed linear birefringence, which causes the emergence of the dependences of the integrated elliptical birefringence and the ellipticity and azimuth of the major axis of the ellipse, as well as the polarization state of radiation (PSR), on the length of optical fiber has been considered. Optical spun-fibers are subjected to a strong mechanical twisting, which is frozen into the structure of the optical fiber upon cooling, in the process of being drawn out from the workpiece. Since the values of the local polarization parameters of coiled spunwaveguides vary according to a rather complex law, the calculations were carried out by numerical modeling of the parameters of the Jones matrices. Since the rotation speed of the axes of the birefringence is constant on a relatively short segment of a coiled optical spun-fiber in the accompanying torsion (helical) coordinate system, the so-called "Ginzburg helical polarization modes" (GHPMs)—two mutually orthogonal ellipses with the opposite directions of traversal, the axis of which rotate relative to the fixed coordinate system uniformly and unidirectionally—are approximately the local normal polarization modes of such optical fiber. It has been shown that, despite the fact that the unperturbed linear birefringence of the spun-fibers significantly exceeds the linear birefringence, which is caused by the winding on a coil, the integral birefringence of an extended segment of such a fiber coincides in order of magnitude with the linear birefringence, which is caused by the winding on the coil, and the integral polarization modes tend asymptotically to circular ones. It has been also shown that the values of the circular birefringence of twisted single-mode fibers, which were calculated in a nonrotating and torsion helical coordinate systems, differ significantly. It has been shown that the polarization phenomena occur

  5. Scattering of linearly polarized Bessel beams by dielectric spheres

    Science.gov (United States)

    Shoorian, Hamed

    2017-09-01

    The scattering of a Linearly Polarized Bessel Beam (LPBB) by an isotropic and homogenous dielectric sphere is investigated. Using analytical relation between the cylindrical and the spherical vector wave functions, all the closed- form analytical expressions, in terms of spherical wave-functions expansions, are derived for the scattered field. It is shown that in the case of conical angle of incident Bessel beam is equal to zero, the Linearly Polarized Bessel Beam becomes a plane wave and its scattering coefficients become the same as the expansion coefficients of plane wave in Mie theory. The transverse Cartesian and spherical components of the electric field, scattered by a sphere are shown in the z-plane for different cases, moreover the intensity of the incident Bessel beam and the effects of its conical angle on the scattered field and the field inside the sphere are investigated. To quantitatively study the scattering phenomenon and the variations of the fields inside and outside of the sphere, the scattering and absorption efficiencies are obtained for the scattering of the linearly-polarized Bessel beam, and are compared with those of the plane wave scattering.

  6. Simulation of AZ-PN100 resist pattern fluctuation in X-ray lithography, including synchrotron beam polarization

    International Nuclear Information System (INIS)

    Scheckler, E.W.; Ogawa, Taro; Tanaka, Toshihiko; Takeda, Eiji; Oizumi, Hiroaki.

    1993-01-01

    A new simulation model for nanometer-scale pattern fluctuation in X-ray lithography is presented and applied to a study of AZ-PN100 negative chemical amplification resist. The exposure simulation considers polarized photons from a synchrotron radiation (SR) source. Monte Carlo simulation of Auger and photoelectron generation is followed by electron scattering simulation to determine the deposited energy distribution at the nanometer scale, including beam polarization effects. An acid-catalyst random walk model simulates the post-exposure bake (PEB) step. Fourier transform infrared (FTIR) spectroscopy and developed resist thickness measurements are used to fit PEB and rate models for AZ-PN100. A polymer removal model for development simulation predicts the macroscopic resist shape and pattern roughness. The simulated 3σ linewidth variation is in excess of 24 nm. Simulation also shows a detrimental effect if the beam polarization is perpendicular to the line. Simulation assuming a theoretical ideal exposure yields a 50 nm minimum line for standard process conditions. (author)

  7. Linearly Polarized IR Spectroscopy Theory and Applications for Structural Analysis

    CERN Document Server

    Kolev, Tsonko

    2011-01-01

    A technique that is useful in the study of pharmaceutical products and biological molecules, polarization IR spectroscopy has undergone continuous development since it first emerged almost 100 years ago. Capturing the state of the science as it exists today, "Linearly Polarized IR Spectroscopy: Theory and Applications for Structural Analysis" demonstrates how the technique can be properly utilized to obtain important information about the structure and spectral properties of oriented compounds. The book starts with the theoretical basis of linear-dichroic infrared (IR-LD) spectroscop

  8. Atomic collision experiments using pulsed synchrotron radiation

    International Nuclear Information System (INIS)

    Arikawa, Tatsuo; Watanabe, Tsutomu.

    1982-01-01

    High intensity and continuous nature of the synchrotron radiation are the properties that are fundamentally important for studies of some atomic collision experiments, and many processes have been investigated by using these characteristics. However, so far the property that the radiation is highly polarized and pulsed in time has not been exploited significantly in atomic physics. As an example of the atomic processes relevant to such polarized and pulsed features of the synchrotron radiation, collisions involving optically-allowed excited atoms and molecules will be presented. (author)

  9. 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

  10. Polarization and ellipticity of high-order harmonics from aligned molecules generated by linearly polarized intense laser pulses

    International Nuclear Information System (INIS)

    Le, Anh-Thu; Lin, C. D.; Lucchese, R. R.

    2010-01-01

    We present theoretical calculations for polarization and ellipticity of high-order harmonics from aligned N 2 , CO 2 , and O 2 molecules generated by linearly polarized lasers. Within the rescattering model, the two polarization amplitudes of the harmonics are determined by the photo-recombination amplitudes for photons emitted with polarization parallel or perpendicular to the direction of the same returning electron wave packet. Our results show clear species-dependent polarization states, in excellent agreement with experiments. We further note that the measured polarization ellipse of the harmonic furnishes the needed parameters for a 'complete' experiment in molecules.

  11. National Synchrotron Light Source: vacuum system for National Synchrotron Light Source

    International Nuclear Information System (INIS)

    Schuchman, J.C.; Godel, J.B.; Jordan, W.; Oversluizen, T.

    1978-01-01

    The National Synchrotron Light Source (NSLS), a 24 million dollar project under construction at Brookhaven National Laboratory (BNL), is a research facility dedicated to the production of synchrotron radiation. Synchrotron radiation is that radiation produced by the acceleration of charged particles at near the speed of light. This facility will provide a continuous spectrum of radiation from the vacuum ultraviolet to the hard x-ray range. The radiation will be highly intense, 100% polarized, extremely well collimated and will have a pulsed time structure. The radiation will be produced in two electron storage rings at energies of 700 MeV and 2.5 GeV, respectively. A maximum of one ampere at 2 GeV, or one-half ampere at 2.5 GeV, of electron beam will be stored

  12. The spin polarized linear response from density functional theory: Theory and application to atoms

    Energy Technology Data Exchange (ETDEWEB)

    Fias, Stijn, E-mail: sfias@vub.ac.be; Boisdenghien, Zino; De Proft, Frank; Geerlings, Paul [General Chemistry (ALGC), Vrije Universiteit Brussel (Free University Brussels – VUB), Pleinlaan 2, 1050 Brussels (Belgium)

    2014-11-14

    Within the context of spin polarized conceptual density functional theory, the spin polarized linear response functions are introduced both in the [N, N{sub s}] and [N{sub α}, N{sub β}] representations. The mathematical relations between the spin polarized linear response functions in both representations are examined and an analytical expression for the spin polarized linear response functions in the [N{sub α}, N{sub β}] representation is derived. The spin polarized linear response functions were calculated for all atoms up to and including argon. To simplify the plotting of our results, we integrated χ(r, r′) to a quantity χ(r, r{sup ′}), circumventing the θ and ϕ dependence. This allows us to plot and to investigate the periodicity throughout the first three rows in the periodic table within the two different representations. For the first time, χ{sub αβ}(r, r{sup ′}), χ{sub βα}(r, r{sup ′}), and χ{sub SS}(r, r{sup ′}) plots have been calculated and discussed. By integration of the spin polarized linear response functions, different components to the polarisability, α{sub αα}, α{sub αβ}, α{sub βα}, and α{sub ββ} have been calculated.

  13. Photonic engineering of highly linearly polarized quantum dot emission at telecommunication wavelengths

    Science.gov (United States)

    Mrowiński, P.; Emmerling, M.; Schneider, C.; Reithmaier, J. P.; Misiewicz, J.; Höfling, S.; Sek, G.

    2018-04-01

    In this work, we discuss a method to control the polarization anisotropy of spontaneous emission from neutral excitons confined in quantum-dot-like nanostructures, namely single epitaxial InAs quantum dashes emitting at telecom wavelengths. The nanostructures are embedded inside lithographically defined, in-plane asymmetric photonic mesa structures, which generate polarization-dependent photonic confinement. First, we study the influence of the photonic confinement on the polarization anisotropy of the emission by photoluminescence spectroscopy, and we find evidence of different contributions to a degree of linear polarization (DOLP), i.e., from the quantum dash and the photonic mesa, in total giving rise to DOLP =0.85 . Then, we perform finite-difference time-domain simulations of photonic confinement, and we calculate the DOLP in a dipole approximation showing well-matched results for the established model. Furthermore, by using numerical calculations, we demonstrate several types of photonic confinements where highly linearly polarized emission with DOLP of about 0.9 is possible by controlling the position of a quantum emitter inside the photonic structure. Then, we elaborate on anisotropic quantum emitters allowing for exceeding DOLP =0.95 in an optimized case, and we discuss the ways towards efficient linearly polarized single photon source at telecom bands.

  14. Realizing Broadband and Invertible Linear-to-circular Polarization Converter with Ultrathin Single-layer Metasurface

    Science.gov (United States)

    Li, Zhancheng; Liu, Wenwei; Cheng, Hua; Chen, Shuqi; Tian, Jianguo

    2015-01-01

    The arbitrary control of the polarization states of light has attracted the interest of the scientific community because of the wide range of modern optical applications that such control can afford. However, conventional polarization control setups are bulky and very often operate only within a narrow wavelength range, thereby resisting optical system miniaturization and integration. Here, we present the basic theory, simulated demonstration, and in-depth analysis of a high-performance broadband and invertible linear-to-circular (LTC) polarization converter composed of a single-layer gold nanorod array with a total thickness of ~λ/70 for the near-infrared regime. This setup can transform a circularly polarized wave into a linearly polarized one or a linearly polarized wave with a wavelength-dependent electric field polarization angle into a circularly polarized one in the transmission mode. The broadband and invertible LTC polarization conversion can be attributed to the tailoring of the light interference at the subwavelength scale via the induction of the anisotropic optical resonance mode. This ultrathin single-layer metasurface relaxes the high-precision requirements of the structure parameters in general metasurfaces while retaining the polarization conversion performance. Our findings open up intriguing possibilities towards the realization of novel integrated metasurface-based photonics devices for polarization manipulation, modulation, and phase retardation. PMID:26667360

  15. Spin transport at the international linear collider and its impact on the measurement of polarization

    Energy Technology Data Exchange (ETDEWEB)

    Beckmann, Moritz

    2013-12-15

    At the planned International Linear Collider (ILC), the longitudinal beam polarization needs to be determined with an unprecedented precision. For that purpose, the beam delivery systems (BDS) are equipped with two laser Compton polarimeters each, which are foreseen to achieve a systematic uncertainty of {<=} 0.25 %. The polarimeters are located 1.6 km upstream and 150 m downstream of the e{sup +}e{sup -} interaction point (IP). The average luminosity-weighted longitudinal polarization P{sup lumi}{sub z}, which is the decisive quantity for the experiments, has to be determined from these measurements with the best possible precision. Therefore, a detailed understanding of the spin transport in the BDS is mandatory to estimate how precise the longitudinal polarization at the IP is known from the polarimeter measurements. The envisaged precision for the propagation of the measurement value is {<=} 0.1 %. This thesis scrutinizes the spin transport in view of the achievable precision. A detailed beamline simulation for the BDS has been developed, including the simulation of the beam-beam collisions at the IP. The following factors which might limit the achievable precision is investigated: a variation of the beam parameters, the beam alignment precision at the polarimeters and the IP, the bunch rotation at the IP, the detector magnets, the beam-beam collisions, the emission of synchrotron radiation and misalignments of the beamline elements. In absence of collisions, a precision of 0.085% on the propagation of the measured longitudinal polarization has been found achievable. This result however depends mainly on the presumed precisions for the parallel alignment of the beam at the polarimeters and for the alignment of polarization vector. In presence of collisions, the measurement at the downstream polarimeter depends strongly on the intensity of the collision and the size of the polarimeter laser spot. Therefore, a more detailed study of the laser-bunch interaction is

  16. Report of the polarization group

    International Nuclear Information System (INIS)

    Ford, W.; Kondo, K.; Martin, F.; Manning, G.; Miller, D.; Prescott, C.

    1975-01-01

    The use of longitudinal polarization in the reaction e + e - → μ + μ - was studied. Modifications of the magnetic insertion which could reduce synchrotron radiation by two or more were considered. In addition, a specific design is suggested which incorporates the optimized magnetic configuration; it is assumed that no particle detection is necessary near the interaction vertex and the synchrotron radiation is ''dumped'' up - and downstream. Also considered were vacuum chambers in which the synchrotron radiation is absorbed locally so that shielded regions are provided for detectors near the interaction vertex. A scheme for rotating the polarization outside the experiment areas is detailed; in this way the design of experiments is greatly simplified. Local intense ionization of residual gas in the interaction region due to synchrotron radiation at the insertion was studied. Finally, some general considerations in the production and measurement of beam polarization are summarized. 2 figures

  17. In-line phase retarder and polarimeter for conversion of linear to circular polarization

    Energy Technology Data Exchange (ETDEWEB)

    Kortright, J.B.; Smith, N.V.; Denlinger, J.D. [Lawrence Berkeley National Lab., CA (United States)] [and others

    1997-04-01

    An in-line polarimeter including phase retarder and linear polarizer was designed and commissioned on undulator beamline 7.0 for the purpose of converting linear to circular polarization for experiments downstream. In commissioning studies, Mo/Si multilayers at 95 eV were used both as the upstream, freestanding phase retarder and the downstream linear polarized. The polarization properties of the phase retarder were characterized by direct polarimetry and by collecting MCD spectra in photoemission from Gd and other magnetic surfaces. The resonant birefringence of transmission multilayers results from differing distributions of s- and p-component wave fields in the multilayer when operating near a structural (Bragg) interference condition. The resulting phase retardation is especially strong when the interference is at or near the Brewster angle, which is roughly 45{degrees} in the EUV and soft x-ray ranges.

  18. MgII Linear Polarization Measurements Using the MSFC Solar Ultraviolet Magnetograph

    Science.gov (United States)

    West, Edward; Cirtain, Jonathan; Kobayahsi, Ken; Davis, John; Gary, Allen; Adams, Mitzi

    2011-01-01

    This paper will describe the Marshall Space Flight Center's Solar Ultraviolet Magnetograph (SUMI) sounding rocket program, with emphasis on the polarization characteristics of the VUV optics and their spectral, spatial and polarization resolution. SUMI's first flight (7/30/2010) met all of its mission success criteria and this paper will describe the data that was acquired with emphasis on the MgII linear polarization measurements.

  19. The Stanford Synchrotron Radiation Laboratory, 20 years of synchrotron light

    International Nuclear Information System (INIS)

    Cantwell, K.

    1993-08-01

    The Stanford Synchrotron Radiation Laboratory (SSRL) is now operating as a fully dedicated light source with low emittance electron optics, delivering high brightness photon beams to 25 experimental stations six to seven months per year. On October 1, 1993 SSRL became a Division of the Stanford Linear Accelerator Center, rather than an Independent Laboratory of Stanford University, so that high energy physics and synchrotron radiation now function under a single DOE contract. The SSRL division of SLAC has responsibility for operating, maintaining and improving the SPEAR accelerator complex, which includes the storage ring and a 3 GeV injector. SSRL has thirteen x-ray stations and twelve VUV/Soft x-ray stations serving its 600 users. Recently opened to users is a new spherical grating monochromator (SGM) and a multiundulator beam line. Circularly polarized capabilities are being exploited on a second SGM line. New YB 66 crystals installed in a vacuum double-crystal monochromator line have sparked new interest for Al and Mg edge studies. One of the most heavily subscribed stations is the rotation camera, which has been recently enhanced with a MAR imaging plate detector system for protein crystallography on a multipole wiggler. Under construction is a new wiggler-based structural molecular biology beam line with experimental stations for crystallography, small angle scattering and x-ray absorption spectroscopy. Plans for new developments include wiggler beam lines and associated facilities specialized for environmental research and materials processing

  20. Linear and nonlinear response matrix and its application to the SIS18 synchrotron

    International Nuclear Information System (INIS)

    Parfenova, Angelina

    2008-01-01

    This Thesis is dedicated to the numerical as well as the experimental study of beam dynamics in circular accelerators. The experimental part was undertaken in the SIS18 synchrotron. The detailed description of the experiments contained in this work can be considered as a starting point for future experiments and machine development. The work has the following structure. In Chapter 2 an overview of the GSI and FAIR accelerator facilities, and a general description of the SIS18 instrumentation related to the study of this work are given. The expected SIS18 performance in view of the upgrade program for FAIR project are outlined. The main beam dynamics issues connected with the purpose of this work are discussed. Chapter 3 is devoted to the study of linear beam dynamics in the SIS18. The resonance beam loss measurements were carried out with residual gas profile monitor in the SIS18 (Chapter 4). In the frame of this work a novel technique 'nonlinear tune response matrix method' to identify strengths, polarities and locations of nonlinear errors in circular accelerators is developed (Chapter 5). In the method the feed down effect of the nonlinear components at level of linear tune response to the closed-orbit change is explored. The closed-orbit change is introduced by varying correction steerers. The tune values are retrieved from the spectrum of coherent betatron oscillations excited by a fast kick. The theoretical background, the robustness of the method and numerical examples for the SIS18 using numerical library MICROMAP are presented. The technique to measure lattice nonlinearities was experimentally validated in the SIS18 where two normal as well as two skew sextupolar errors of the order of natural errors were reconstructed with a tolerant precision. It was shown how this technique can be applied to reconstruct sextupolar nonlinear errors in the complete machine. In Chapter 6 the main results and the conclusions of this work are outlined. (orig.)

  1. Polarization burst in the BL Lac object AO 0235 + 164

    Energy Technology Data Exchange (ETDEWEB)

    Impey, C D; Brand, P W.J.L. [Edinburgh Univ. (UK). Dept. of Astronomy; Tapia, S [Steward Observatory, Tucson, AZ (USA)

    1982-01-01

    Simultaneous infrared and optical polarimetry and photometry have been obtained for AO 0235 + 164 covering a five night period. The object underwent a polarization burst during which the 2.2 ..mu..m polarization rose from 17.5 to 28.7 per cent and fell again to 14.9 per cent. At its peak the degree of optical polarization was 43.9 per cent, the highest linear polarization observed in a BL Lac object. The data show the degree of polarization to increase towards shorter wavelengths, and the effect is inconsistent with either dilution by a galactic component or simple one-component synchrotron models. The large changes in polarization are not accompanied by large changes in flux, a result which is difficult to explain using conventional models of these objects. Other implications of the luminosity, polarization and variability are discussed.

  2. Synchrotron radiation linear dichroism (SRLD) investigation of the electronictransitions of quinizarin, chrysazin, and anthrarufin

    DEFF Research Database (Denmark)

    Nguyen, Duy Duc; Jones, Nykola C.; Hoffmann, Søren Vrønning

    2010-01-01

    The electronic transitions of the three , (alpha), (alphaPrime) -dihydroxy derivatives of anthraquinone, 1,4-dihydroxy-, 1,8-dihydroxy-, and 1,5-dihydroxy-9,10-anthraquinone (quinizarin, chrysazin, and anthrarufin), were investigated by synchrotron radiation linear dichroism (SRLD) spectroscopy...... the investigated region (15,000-58,000cm-1), essentially similar wavenumbers, intensities, and transition moment directions were determined for chrysazin and anthrarufin, while the spectrum of quinizarin deviated significantly. The results of time-dependent density functional theory (TD-DFT) calculations were...

  3. Properties of synchrotron radiation

    International Nuclear Information System (INIS)

    Materlik, G.

    1982-01-01

    This paper forms the introductory chapter to a book concerning the use of synchrotron radiation for investigation of the structure and mechanism of biological macromolecules. After a historical section, the physics of synchrotron radiation is summarized so that the most promising experiments may be extrapolated. Irradiated power and intensity, polarization and angular distribution, brilliance of a real source, and developments such as wigglers and undulators are briefly dealt with. The paper includes a tabulated compilation of proposed and operating machines in 1982, with some of their characteristics. (U.K.)

  4. Vector optical fields with bipolar symmetry of linear polarization.

    Science.gov (United States)

    Pan, Yue; Li, Yongnan; Li, Si-Min; Ren, Zhi-Cheng; Si, Yu; Tu, Chenghou; Wang, Hui-Tian

    2013-09-15

    We focus on a new kind of vector optical field with bipolar symmetry of linear polarization instead of cylindrical and elliptical symmetries, enriching members of family of vector optical fields. We design theoretically and generate experimentally the demanded vector optical fields and then explore some novel tightly focusing properties. The geometric configurations of states of polarization provide additional degrees of freedom assisting in engineering the field distribution at the focus to the specific applications such as lithography, optical trapping, and material processing.

  5. Polarization and dipole effects in hard X-ray photoelectron spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Novak, M. [Universite Libre de Bruxelles, Service de Metrologie Nucleaire (CP 165/84), 50 av. F. D. Roosevelt, B-1050 Brussels (Belgium); Pauly, N., E-mail: nipauly@ulb.ac.be [Universite Libre de Bruxelles, Service de Metrologie Nucleaire (CP 165/84), 50 av. F. D. Roosevelt, B-1050 Brussels (Belgium); Dubus, A. [Universite Libre de Bruxelles, Service de Metrologie Nucleaire (CP 165/84), 50 av. F. D. Roosevelt, B-1050 Brussels (Belgium)

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer X-rays are unpolarized or linearly polarized. Black-Right-Pointing-Pointer A difference of polarization implies a variation in path travelled by the photoelectrons. Black-Right-Pointing-Pointer We show the influence of the polarization on the partial intensity distributions. Black-Right-Pointing-Pointer We also point out the influence of the dipole approximation. Black-Right-Pointing-Pointer We use Monte Carlo simulations. - Abstract: Hard X-ray photoelectron spectroscopy (HXPS) using X-rays in the 1.5-15 keV energy range generated by synchrotron sources becomes an increasingly important analysis technique due to its potential for bulk sensitive measurements. However, besides their high energy, another characteristic of photons generated by synchrotron sources is their linear polarization while X-rays from Al K{alpha} or Mg K{alpha} for instance are unpolarized. This difference implies a possible variation in total path travelled by the photoelectrons generated by the X-rays inside the medium and consequently a modification of the resulting spectrum shape. We show the influence of the polarization on the partial intensity distributions, namely the number of electrons escaping after n inelastic scattering events, for photoelectron with energies of 0.5, 1, 2, 3, 4 and 5 keV and originating from Si 1s{sub 1/2}, Cu 1s{sub 1/2}, Cu 2p{sub 3/2}, Au 4d{sub 3/2} and Au 4f{sub 7/2} subshells. Moreover, we point out the influence of the dipole approximation leading to an underestimation of the partial intensity distributions due to the neglect of the forward-backward asymmetry of the angular photoelectron distribution.

  6. Application of synchrotron radiation to elemental analysis

    International Nuclear Information System (INIS)

    Jones, K.W.; Gordon, B.M.; Hanson, A.L.; Hastings, J.B.; Howells, M.R.; Kraner, H.W.; Chen, J.R.

    1983-01-01

    The use of a synchrotron storage ring as a high brightness source for production of monoergic, variable energy, and highly polarized x-ray beams promises to revolutionize the field of elemental analysis. The results of exploratory work using the Cornell synchrotron facility, CHESS, will be described. Design considerations and features of the new X-Ray Microprobe Facility now under construction at the Brookhaven National Synchrotron Light Source will be presented. This facility will be used for bulk analysis and for microanalysis with an initial spatial resolution of the order of 30 μm

  7. Polarization preservation in the AGS

    International Nuclear Information System (INIS)

    Ratner, L.G.

    1983-01-01

    The successful operation of a high energy polarized beam at the Argonne Zero Gradient Synchrotron (ZGS) with the concommitant development of depolarizing resonance correction techniques has led to the present project of commissioning such a beam at the Brookhaven Alternating Gradient Synchrotron (AGS). A description of the project was presented at the 1981 National Accelerator Conference. I would like to now present a more detailed description of how we plan to preserve the polarization during acceleration, and to present our game plan for tuning through some 50 resonances and reaching our goal of a 26 GeV polarized proton beam with greater than 60% polarization

  8. SR TXRF: performances and perspectives of a dedicated synchrotron beamline

    International Nuclear Information System (INIS)

    Comin, F.; Apostolo, G.

    2000-01-01

    In principle the brilliance of synchrotron radiation x-ray beams combined with a high degree of linear polarization allows to reach at the same time low LLDs, mapping of the impurity distribution and chemical identification for elements as light as Na. The TXRF facility at the European synchrotron radiation facility is installed along a beamline dedicated to industry and is designed to reach ultimate detection limits of 6 x 10 7 at/cm 2 in selected areas, or to map the concentration of contaminants with LLD in the scale 10 9 at/cm 2 . In the present configuration the facility works in vacuum with a single element detector. Loading, unloading and pump down of wafers is completely automatic. Typical DDLs are of few 10 9 at/cm 2 for Na and Al and 10 8 at/cm 2 for transition metals. Absorption spectra (XANES and EXAFS) of TM help in the defining the chemistry of the contaminant. (author)

  9. Design of a dual linear polarization antenna using split ring resonators at X-band

    Science.gov (United States)

    Ahmed, Sadiq; Chandra, Madhukar

    2017-11-01

    Dual linear polarization microstrip antenna configurations are very suitable for high-performance satellites, wireless communication and radar applications. This paper presents a new method to improve the co-cross polarization discrimination (XPD) for dual linear polarized microstrip antennas at 10 GHz. For this, three various configurations of a dual linear polarization antenna utilizing metamaterial unit cells are shown. In the first layout, the microstrip patch antenna is loaded with two pairs of spiral ring resonators, in the second model, a split ring resonator is placed between two microstrip feed lines, and in the third design, a complementary split ring resonators are etched in the ground plane. This work has two primary goals: the first is related to the addition of metamaterial unit cells to the antenna structure which permits compensation for an asymmetric current distribution flow on the microstrip antenna and thus yields a symmetrical current distribution on it. This compensation leads to an important enhancement in the XPD in comparison to a conventional dual linear polarized microstrip patch antenna. The simulation reveals an improvement of 7.9, 8.8, and 4 dB in the E and H planes for the three designs, respectively, in the XPD as compared to the conventional dual linear polarized patch antenna. The second objective of this paper is to present the characteristics and performances of the designs of the spiral ring resonator (S-RR), split ring resonator (SRR), and complementary split ring resonator (CSRR) metamaterial unit cells. The simulations are evaluated using the commercial full-wave simulator, Ansoft High-Frequency Structure Simulator (HFSS).

  10. Linearly polarized photoluminescence of InGaN quantum disks embedded in GaN nanorods.

    Science.gov (United States)

    Park, Youngsin; Chan, Christopher C S; Nuttall, Luke; Puchtler, Tim J; Taylor, Robert A; Kim, Nammee; Jo, Yongcheol; Im, Hyunsik

    2018-05-25

    We have investigated the emission from InGaN/GaN quantum disks grown on the tip of GaN nanorods. The emission at 3.21 eV from the InGaN quantum disk doesn't show a Stark shift, and it is linearly polarized when excited perpendicular to the growth direction. The degree of linear polarization is about 39.3% due to the anisotropy of the nanostructures. In order to characterize a single nanostructure, the quantum disks were dispersed on a SiO 2 substrate patterned with a metal reference grid. By rotating the excitation polarization angle from parallel to perpendicular relative to the nanorods, the variation of overall PL for the 3.21 eV peak was recorded and it clearly showed the degree of linear polarization (DLP) of 51.5%.

  11. 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.

  12. Linearly Polarized Gluons and the Higgs Transverse Momentum Distribution

    NARCIS (Netherlands)

    Boer, Daniel; den Dunnen, Wilco J.; Pisano, Cristian; Schlegel, Marc; Vogelsang, Werner

    2012-01-01

    We study how gluons carrying linear polarization inside an unpolarized hadron contribute to the transverse momentum distribution of Higgs bosons produced in hadronic collisions. They modify the distribution produced by unpolarized gluons in a characteristic way that could be used to determine

  13. The simultaneous measurement of energy and linear polarization of the scattered radiation in resonant inelastic soft x-ray scattering

    Energy Technology Data Exchange (ETDEWEB)

    Braicovich, L., E-mail: lucio.braicovich@polimi.it; Minola, M.; Dellea, G.; Ghiringhelli, G. [CNR-SPIN and Dipartimento di Fisica, Politecnico di Milano, piazza Leonardo Da Vinci 32, Milano I-20133 (Italy); Le Tacon, M. [Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart (Germany); Moretti Sala, M.; Morawe, C.; Peffen, J.-Ch.; Yakhou, F.; Brookes, N. B. [European Synchrotron Radiation Facility, 71 Avenue des Martyrs, Grenoble F-38043 (France); Supruangnet, R. [Synchrotron Light Research Institute, Nakhon Ratchasima (Thailand)

    2014-11-15

    Resonant Inelastic X-ray Scattering (RIXS) in the soft x-ray range is an element-specific energy-loss spectroscopy used to probe the electronic and magnetic excitations in strongly correlated solids. In the recent years, RIXS has been progressing very quickly in terms of energy resolution and understanding of the experimental results, but the interpretation of spectra could further improve, sometimes decisively, from a full knowledge of the polarization of incident and scattered photons. Here we present the first implementation, in a high resolution soft-RIXS spectrometer used to analyze the scattered radiation, of a device allowing the measurement of the degree of linear polarization. The system, based on a graded W/B{sub 4}C multilayer mirror installed in proximity of the CCD detector, has been installed on the AXES spectrometer at the ESRF (European Synchrotron Radiation Facility); it has been fully characterized and it has been used for a demonstration experiment at the Cu L{sub 3} edge on a high-T{sub c} superconducting cuprate. The loss in efficiency suffered by the spectrometer equipped with this test facility was a factor 17.5. We propose also a more advanced version, suitable for a routine use on the next generation of RIXS spectrometers and with an overall efficiency up to 10%.

  14. General formulae for polarization observables in deuteron electrodisintegration and linear relations

    International Nuclear Information System (INIS)

    Arenhoevel, H.; Leidemann, W.; Tomusiak, E.L.

    1993-01-01

    Formal expressions are derived for all possible polarization observables in deuteron electrodisintegration with longitudinally polarized incoming electrons, oriented deuteron targets and polarization analysis of outgoing nucleons. They are given in terms of general structure functions which can be determined experimentally. These structure functions are Hermitean forms of the T-matrix elements which, in principle, allow the determination of all T-matrix elements up to an arbitrary common phase. Since the set of structure functions is overcomplete, linear relations among various structure functions exist which are derived explicitly

  15. 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

  16. Revealing Fundamental Interactions: the Role of Polarized Positrons and Electrons at the Linear Collider

    International Nuclear Information System (INIS)

    Moortgat-Pick, G.; CERN, Durham U. IPPP; 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.; Eberl, H.; Ellis, John R.; Flottman, K.; Frass, H.

    2005-01-01

    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

  17. Revealing Fundamental Interactions: the Role of Polarized Positrons and Electrons at the Linear Collider

    Energy Technology Data Exchange (ETDEWEB)

    Moortgat-Pick, G.; /CERN /Durham U., IPPP; Abe, T.; Alexander, G.; Ananthanarayan, B.; Babich, A.A.; Bharadwaj, V.; Barber, D.; Bartl, A.; Brachmann, A.; Chen, S.; Clarke,; Clendenin, J.E.; Dainton, J.; Desch, K.; Diehl, M.; Dobos, B.; Dorland, T.; Eberl, H.; Ellis, John R.; Flottman, K.; Frass, H.; /CERN /Durham U., IPPP /Colorado U. /Tel-Aviv

    2005-07-06

    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. 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.

  19. Combination of lasers and synchrotron radiation in studies of atomic photoionization

    International Nuclear Information System (INIS)

    Meyer, M.

    2009-01-01

    Recent experiments using the combination of conventional lasers and synchrotron radiation are presented and discussed. The controlled laser-manipulation of atoms prior to ionization by the synchrotron radiation provides an ideal experimental basis for detailed investigations of atomic photoionization. Due to the recent advances in high-resolution electron spectroscopy, it has become possible to analyze the J-resolved fine structure of the final ionic states in the photoionization of laser-excited atoms enabling thereby the determination of the specific influence of the outer electron to the ionization from inner subshells. Especially, the analysis of photoemission satellites and their relative intensities bring out directly the importance of electron correlations. Furthermore, it is shown through some examples of experiments using linearly and circularly polarized radiations, how the study of magnetic dichroisms in the photoionization opens the access to a complete description of the photoionization process, in particular to the determination of partial photoionization cross-sections.

  20. Synchrotron Intensity Gradients as Tracers of Interstellar Magnetic Fields

    Energy Technology Data Exchange (ETDEWEB)

    Lazarian, A.; Yuen, Ka Ho; Lee, Hyeseung; Cho, J. [Department of Astronomy, University of Wisconsin-Madison, 2535 Sterling Hall, 475 North Charter Street, Madison, WI 53706-1507 (United States)

    2017-06-10

    On the basis of the modern understanding of MHD turbulence, we propose a new way of using synchrotron radiation: using synchrotron intensity gradients (SIGs) for tracing astrophysical magnetic fields. We successfully test the new technique using synthetic data obtained with 3D MHD simulations and provide the demonstration of the practical utility of the technique by comparing the directions of magnetic fields that are obtained with PLANCK synchrotron intensity data to the directions obtained with PLANCK synchrotron polarization data. We demonstrate that the SIGs can reliably trace magnetic fields in the presence of noise and can provide detailed maps of magnetic field directions. We also show that the SIGs are relatively robust for tracing magnetic fields while the low spatial frequencies of the synchrotron image are removed. This makes the SIGs applicable to the tracing of magnetic fields using interferometric data with single-dish measurement absent. We discuss the synergy of using the SIGs together with synchrotron polarization in order to find the actual direction of the magnetic fields and quantify the effects of Faraday rotation as well as with other ways of studying astrophysical magnetic fields. We test our method in the presence of noise and the resolution effects. We stress the complementary nature of the studies using the SIG technique and those employing the recently introduced velocity gradient techniques that trace magnetic fields using spectroscopic data.

  1. Synchrotron Intensity Gradients as Tracers of Interstellar Magnetic Fields

    International Nuclear Information System (INIS)

    Lazarian, A.; Yuen, Ka Ho; Lee, Hyeseung; Cho, J.

    2017-01-01

    On the basis of the modern understanding of MHD turbulence, we propose a new way of using synchrotron radiation: using synchrotron intensity gradients (SIGs) for tracing astrophysical magnetic fields. We successfully test the new technique using synthetic data obtained with 3D MHD simulations and provide the demonstration of the practical utility of the technique by comparing the directions of magnetic fields that are obtained with PLANCK synchrotron intensity data to the directions obtained with PLANCK synchrotron polarization data. We demonstrate that the SIGs can reliably trace magnetic fields in the presence of noise and can provide detailed maps of magnetic field directions. We also show that the SIGs are relatively robust for tracing magnetic fields while the low spatial frequencies of the synchrotron image are removed. This makes the SIGs applicable to the tracing of magnetic fields using interferometric data with single-dish measurement absent. We discuss the synergy of using the SIGs together with synchrotron polarization in order to find the actual direction of the magnetic fields and quantify the effects of Faraday rotation as well as with other ways of studying astrophysical magnetic fields. We test our method in the presence of noise and the resolution effects. We stress the complementary nature of the studies using the SIG technique and those employing the recently introduced velocity gradient techniques that trace magnetic fields using spectroscopic data.

  2. Measuring the momentum distribution of the unpaired spin electrons in ferromagnets using synchrotron radiation

    International Nuclear Information System (INIS)

    Mills, D.M.

    1988-12-01

    The dominant term in the x-ray Compton cross-section of an electron is the interaction of the photon and the electron's charge. Platzman and Tsoar many years ago pointed out that there is also an interaction between an x-ray and the electron's spin and in principle this interaction can give information on the momentum distribution of the unpaired spin electrons in the solid. Unfortunately, the spin sensitive term is not only small compared to the charge term, but in addition couples to the photons in first order only with that components of the x-ray beam that is circularly polarized. A lack of intense sources of circularly polarized x-rays combined with the relative small size of the spin sensitive term makes measurements of the momentum distributions of unpaired spin electrons difficult, resulting in little experiment progress initially made in spin or magnetic Compton scattering. In the past several years, interest in spin sensitive Compton scattering has been revived due in large part to the availability of intense beams of high energy photons from synchrotron radiation sources. The radiation from storage ring sources has well defined polarization states; highly linearly polarized in the orbital plane and elliptically polarized above and below the plane of the orbit of the circulating particles. The high flux and unique polarization properties of synchrotron radiation sources have greatly facilitated measurements of the momentum distributions of the unpaired spin electrons in ferromagnetic solids. Recent results of the work of several groups will be presented, along with some thoughts on the impact that the next generation of storage rings, such as the Advanced Photon Source, and insertion devices specifically designed to produce circularly polarized x-ray beams will have on the field of magnetic Compton scattering. 21 refs., 6 figs

  3. Spin physics with polarized electrons at the SLC [Stanford Linear Collider

    International Nuclear Information System (INIS)

    Moffeit, K.C.

    1990-11-01

    The Stanford Linear Collider was designed to accommodate polarized electron beams. A gallium arsenide-based photon emission source will provide a beam of longitudinally polarized electrons of about 40 percent polarization. A system of bend magnets and a superconducting solenoid will be used to rotate the spins so that the polarization is preserved while the 1.21 GeV electrons are stored in the damping ring. Another set of bend magnets and two superconducting solenoids orient the spin vectors so that longitudinal polarization of the electrons is achieved at the collision point with the unpolarized positions. A system to monitor the polarization based on Moeller and Compton scattering will be used. Spin physics with longitudinally polarized electrons uses the measurement of the left-right asymmetry to provide tests of the Standard Model. The uncertainty in the measurement is precise enough to be sensitive to the effects of particles which can not be produced directly in the machines we have today. 5 refs

  4. Dispersion relation of linearly polarized strong electromagnetic waves

    Energy Technology Data Exchange (ETDEWEB)

    Ferrari, A; Massaglia, S [Consiglio Nazionale delle Ricerche, Turin (Italy). Lab. di Cosmo-Geofisica; Dobrowolny, M [Comitato Nazionale per l' Energia Nucleaire, Frascati (Italy). Lab. Plasma Spazio

    1975-12-15

    A numerical study is presented of the dispersion relation of linearly polarized strong electromagnetic waves in a cold electron plasma. The nonlinear effects introduced by the relativistic motion of electrons are: (1) the dispersion relation depends explicitly on the field strength ..cap alpha..=eE/sub 0//mc..omega../sub 0/, and (2) the propagation of modes with frequencies below the formal electron plasma frequency is allowed.

  5. Observations on the variability of linear polarization in late-type dwarf stars

    Energy Technology Data Exchange (ETDEWEB)

    Huovelin, J.; Linnaluoto, S.; Tuominen, I.; Virtanen, H.

    1989-04-01

    Broadband (UBV) linear polarimetric observations of a sample of late-type (F7-K5) dwarfs are reported. The observations include ten stars and extend over a maximum of 20 nights. Seven stars show significant temporal variability of polarization, which could be interpreted as rotational modulation due to slowly varying magnetic regions. Magnetic intensification in saturated Zeeman sensitive absorption lines is suggested as the dominant effect connecting linear polarization with magnetic activity in the most active single late-type dwarfs, while the wavelength dependence in the less active stars could also be due to a combination of Rayleigh and Thomson scattering.

  6. Optical asymmetric cryptography based on elliptical polarized light linear truncation and a numerical reconstruction technique.

    Science.gov (United States)

    Lin, Chao; Shen, Xueju; Wang, Zhisong; Zhao, Cheng

    2014-06-20

    We demonstrate a novel optical asymmetric cryptosystem based on the principle of elliptical polarized light linear truncation and a numerical reconstruction technique. The device of an array of linear polarizers is introduced to achieve linear truncation on the spatially resolved elliptical polarization distribution during image encryption. This encoding process can be characterized as confusion-based optical cryptography that involves no Fourier lens and diffusion operation. Based on the Jones matrix formalism, the intensity transmittance for this truncation is deduced to perform elliptical polarized light reconstruction based on two intensity measurements. Use of a quick response code makes the proposed cryptosystem practical, with versatile key sensitivity and fault tolerance. Both simulation and preliminary experimental results that support theoretical analysis are presented. An analysis of the resistance of the proposed method on a known public key attack is also provided.

  7. Alteration in non-classicality of light on passing through a linear polarization beam splitter

    Science.gov (United States)

    Shukla, Namrata; Prakash, Ranjana

    2016-06-01

    We observe the polarization squeezing in the mixture of a two mode squeezed vacuum and a simple coherent light through a linear polarization beam splitter. Squeezed vacuum not being squeezed in polarization, generates polarization squeezed light when superposed with coherent light. All the three Stokes parameters of the light produced on the output port of polarization beam splitter are found to be squeezed and squeezing factor also depends upon the parameters of coherent light.

  8. Polarization properties of below-threshold harmonics from aligned molecules H2+ in linearly polarized laser fields.

    Science.gov (United States)

    Dong, Fulong; Tian, Yiqun; Yu, Shujuan; Wang, Shang; Yang, Shiping; Chen, Yanjun

    2015-07-13

    We investigate the polarization properties of below-threshold harmonics from aligned molecules in linearly polarized laser fields numerically and analytically. We focus on lower-order harmonics (LOHs). Our simulations show that the ellipticity of below-threshold LOHs depends strongly on the orientation angle and differs significantly for different harmonic orders. Our analysis reveals that this LOH ellipticity is closely associated with resonance effects and the axis symmetry of the molecule. These results shed light on the complex generation mechanism of below-threshold harmonics from aligned molecules.

  9. Polarized vacuum ultraviolet and X-radiation

    International Nuclear Information System (INIS)

    Samson, J.A.R.

    1978-01-01

    The most intense source of polarized vacuum UV and X-radiation is synchrotron radiation, which exhibits a degree of partially polarized light between about 80-100%. However, the radiation transmitted by vacuum UV monochromators can also be highly polarized. The Seya-Namioka type of monochromator can produce partially polarized radiation between 50-80%. For certain experiments it is necessary to know the degree of polarisation of the radiation being used. Also, when synchrotron radiation and a monochromator are combined the polarization characteristic of both should be known in order to make full use of these polarization properties. The polarizing effect on monochromators (i.e. diffraction gratings) have been measured at the Seya angle and at grazing angles for various spectral orders. The author presents the first experimental evidence that the reciprocity law holds for polarization by reflection where the angle of incidence and diffraction are unequal. These results are reviewed along with the techniques for measuring the degree of polarization. (Auth.)

  10. Broad-band linear polarization and magnetic intensification in rotating magnetic stars

    International Nuclear Information System (INIS)

    Degl'Innocenti, M.L.; Calamai, G.; Degl'Innocenti, E.L.; Patriarchi, P.

    1981-01-01

    Magnetic intensification is proposed as a mechanism to explain the general features of the variable broad-band linear polarization emerging from rotating magnetic stars. This mechanism is studied in detail, and some efforts are made to investigate the wide variety of polarization diagrams that can result from it. Theoretical results are compared with direct observations of the variable magnetic star 53 Cam to determine its geometric and magnetic configuration

  11. COSY Juelich - a cooler synchrotron for unpolarized and polarized medium-energy studies

    International Nuclear Information System (INIS)

    Seyfarth, H.

    2001-01-01

    Full text: The Forschungszentrum Juelich (Research Center Juelich) is one of the sixteen national research institutions in the 'Hermann von Helmholtz Association of German Research Centers'. It is dedicated to fundamental and applied research and development which can be summarized under five priorities: (i) structure of matter and materials research, (ii) information technology, (iii) life sciences, (iv) environment precaution research, and (v) energy technology. As one of the institutes within (i). the Institut fur Kernphysik (Institute for Nuclear Research) operates the COSY cooler synchrotron which allows to accelerate unpolarized and polarized protons and deuterons to the maximum momentum of 3450 MeV/c (2640 MeV and 2050 MeV kinetic energy for protons and deuterons, respectively). At low energy electron cooling can be used for beam preparation, whereas stochastic cooling can be applied to the accelerated beam. In the first years of operation since 1993 the experiments have been performed with the unpolarized proton beam. Since 1997 the polarized proton beam is available with increasing intensity and a typical degree of polarization of about 75 % up to the maximum beam energy. In 2000 the first unpolarized deuteron beam could be accelerated and stored at the maximum energy. Four target places exist for the internal experiments PISA. EDDA, COSY-II, and ANKE which use the circulating beam with thin solid strip or fiber targets and gas targets. The four experiments TOF, MOMO, GEM, NESSI, and JESSICA are using external beams. The programs of the experiments JESSICA (Juelich Experimental Spallation Setup in the COSY Area), NESSI (Neutron Scintillator and Silicon), and PISA (Proton Induced Spallation) aim at the measurement of data needed or the design of the target station of the planned European Spallation neutron Source (ESS). The set-up of PISA is replacing the earlier experiment COSY-13 which successfully completed its investigations on the production of

  12. Photodisintegration of aligned deuterons at astrophysical energies using linearly polarized photons

    International Nuclear Information System (INIS)

    Shilpashree, S.P.; Sirsi, Swarnamala; Ramachandran, G.

    2013-01-01

    Following the model independent approach to deuteron photodisintegration with linearly polarized γ-rays, we show that the measurements of the tensor analyzing powers on aligned deuterons along with the differential cross-section involve five different linear combinations of the isovector E1 ν j ; j = 0, 1, 2 amplitudes interfering with the isoscalar M1 s and E2 s amplitudes. This is of current interest in view of the recent experimental finding [M. A. Blackston et al., Phys. Rev. C78 (2008) 034003] that the three E1 ν j amplitudes are distinct and also the reported experimental observation [B. D. Sawatzky, Ph.D. thesis, University of Virginia (2005)] on the front–back (polar angle) asymmetry in the differential cross-section. (author)

  13. Generation of linearly polarized resonant transition radiation X-ray beam

    International Nuclear Information System (INIS)

    Yajima, Kazuaki; Awata, Takaaki; Ikeda, Mitsuharu; Ikeda, Kenichi; Yogo, Akifumi; Itoh, Akio; Imanishi, Nobutsugu

    2000-01-01

    We have proposed a method to generate almost linearly polarized resonant transition radiation X rays by using a rectangular slit placed on an electron beam axis. Our calculation predicted that the linearity is 93.5% for the resonant transition radiation X-ray beam extracted through a slit of 0.5 mrad long and 0.2 mrad wide in case of 1-GeV electron beam irradiating a 7.5-μm thick Kapton foil stack. (author)

  14. Generation of linearly polarized resonant transition radiation X-ray beam

    Energy Technology Data Exchange (ETDEWEB)

    Yajima, Kazuaki; Awata, Takaaki; Ikeda, Mitsuharu; Ikeda, Kenichi; Yogo, Akifumi; Itoh, Akio; Imanishi, Nobutsugu [Kyoto Univ. (Japan). Dept. of Nuclear Engineering

    2000-03-01

    We have proposed a method to generate almost linearly polarized resonant transition radiation X rays by using a rectangular slit placed on an electron beam axis. Our calculation predicted that the linearity is 93.5% for the resonant transition radiation X-ray beam extracted through a slit of 0.5 mrad long and 0.2 mrad wide in case of 1-GeV electron beam irradiating a 7.5-{mu}m thick Kapton foil stack. (author)

  15. 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.

  16. The Role of polarized positrons and electrons in revealing fundamental interactions at the linear collider

    CERN Document Server

    Moortgat-Pick, G.; 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, Tyler McMillan; Dreiner, H.K.; Eberl, H.; Ellis, John R.; Flottmann, K.; Fraas, H.; Franco-Sollova, F.; Franke, F.; Freitas, A.; Goodson, J.; Gray, J.; Han, A.; Heinemeyer, S.; Hesselbach, S.; Hirose, T.; Hohenwarter-Sodek, K.; Juste, A.; Kalinowski, J.; Kernreiter, T.; Kittel, O.; Kraml, S.; Langenfeld, U.; Majerotto, W.; Martinez, A.; Martyn, H.U.; Mikhailichenko, A.; Milstene, C.; Menges, W.; Meyners, N.; Monig, K.; Moffeit, K.; Moretti, S.; Nachtmann, O.; Nagel, F.; Nakanishi, T.; Nauenberg, U.; Nowak, H.; Omori, T.; Osland, P.; Pankov, A.A.; Paver, N.; Pitthan, R.; Poschl, R.; Porod, W.; Proulx, J.; Richardson, P.; Riemann, S.; Rindani, S.D.; Rizzo, T.G.; Schalicke, A.; Schuler, P.; Schwanenberger, C.; Scott, D.; Sheppard, J.; Singh, R.K.; Sopczak, A.; Spiesberger, H.; Stahl, A.; Steiner, H.; Wagner, A.; Weber, A.M.; Weiglein, G.; Wilson, G.W.; Woods, M.; Zerwas, P.; Zhang, J.; Zomer, F.

    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.

  17. The Role of polarized positrons and electrons in revealing fundamental interactions at the linear collider

    Energy Technology Data Exchange (ETDEWEB)

    Moortgat-Pick, G.; /CERN /Durham U., IPPP; Abe, T.; Alexander, G.; Ananthanarayan, B.; Babich, A.A.; Bharadwaj, V.; Barber, D.; Bartl, A.; Brachmann, A.; Chen, S.; Clarke,; Clendenin, J.E.; Dainton, J.; Desch, K.; Diehl, M.; Dobos, B.; Dorland, T.; Eberl, H.; Ellis, John R.; Flottman, K.; Frass, H.; /CERN /Durham U., IPPP /Colorado U. /Tel-Aviv

    2005-07-01

    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. Linearly and circularly polarized laser photoinduced molecular order in azo dye doped polymer films

    Directory of Open Access Journals (Sweden)

    Saad Bendaoud

    2017-01-01

    Full Text Available Photo-induced behavior of Azo Disperse one (AZD1 doped Poly(Methyl MethAcrylate (PMMA using both linear and circular polarized light is studied. The anisotropy is not erased by the circular polarization light. The circular polarization light combined with relatively long lifetime of the cis state in azo dye doped polymers activate all transverse directions of the angular hole burning through the spot in the film inducing anisotropy. Under circular polarized light, there is no orientation perpendicularly to the helex described by the rotating electric field vector, trans molecules reorients in the propagation direction of the pump beam. The polarization state of the probe beam after propagation through the pumped spot depends strongly on the angle of incidence of both pump and probe beams on the input face. In the case where circular polarized pump and probe beams are under the same angle of incidence, the probe beam “sees” anisotropic film as if it is isotropic. Results of this work shows the possibility to reorient azobenzene-type molecules in two orthogonal directions using alternately linearly and circularly polarized beams.

  19. Surface, interface and bulk materials characterization using Indus synchrotron sources

    International Nuclear Information System (INIS)

    Phase, Deodatta M.

    2014-01-01

    Synchrotron radiation sources, providing intense, polarized and stable beams of ultra violet, soft and hard x-ray photons, are having great impact on physics, chemistry, biology, materials science and other areas research. In particular synchrotron radiation has revolutionized materials characterization techniques by enhancing its capabilities for investigating the structural, electronic and magnetic properties of solids. The availability of synchrotron sources and necessary instrumentation has led to considerable improvements in spectral resolution and intensities. As a result, application scope of different materials characterization techniques has tremendously increased particularly in the analysis of solid surfaces, interfaces and bulk materials. The Indian synchrotron storage ring, Indus-1 and Indus-2 are in operation at RRCAT, Indore. The UGC-DAE CSR with the help of university scientist had designed and developed an angle integrated photoelectron spectroscopy (AlPES) beam line on Indus-1 storage ring of 450 MeV and polarized light beam line for soft x-ray absorption spectroscopy (SXAS) on Indus-2 storage ring of 2.5 GeV. (author)

  20. Interaction of low-intensity linearly polarized laser radiation with living tissues: effects on tissular acceleration of skin wound healing

    International Nuclear Information System (INIS)

    Ribeiro, Martha Simoes

    2000-01-01

    According to the Maxwell's equations to optical properties of surfaces, the energy deposition efficiency in a microroughness interface depends on the electrical field polarization component. Considering a linearly polarized beam, this efficiency will depend on the roughness parameters to p-polarized light and it will not depend on such parameters to s-polarized light. In this work it was investigated the effects of low-intensity, linearly polarized He-Ne laser beam on skin wounds healing, considering two orthogonal directions of polarization. We have considered a preferential axis as the animals' spinal column and we aligned the linear laser polarization first parallel, then perpendicular to this direction. Burns about 6 mm in diameter were created with liquid N 2 on the back of the animals and the lesions were irradiated on days 3, 7, 10 and 14 post-wounding, D= 1,0 J/cm 2 . Control lesions were not irradiated. The theoretical model consisted in describing linearly polarized light propagation in biological tissues using transport theory. The degree of polarization was measured in normal and pathological skin samples. It was verified that linearly polarized light can survive in the superficial layers of skin and it can be more preserved in skin under pathological condition when compared with health skin. The analysis of skin wound healing process has demonstrated that the relative direction of the laser polarization plays an important role on the wound healing process by light microscopy, transmission electron microscopy and radioautography. (author)

  1. An analysis of the electromagnetic field in multi-polar linear induction system

    International Nuclear Information System (INIS)

    Chervenkova, Todorka; Chervenkov, Atanas

    2002-01-01

    In this paper a new method for determination of the electromagnetic field vectors in a multi-polar linear induction system (LIS) is described. The analysis of the electromagnetic field has been done by four dimensional electromagnetic potentials in conjunction with theory of the magnetic loops . The electromagnetic field vectors are determined in the Minkovski's space as elements of the Maxwell's tensor. The results obtained are compared with those got from the analysis made by the finite elements method (FEM).With the method represented in this paper one can determine the electromagnetic field vectors in the multi-polar linear induction system using four-dimensional potential. A priority of this method is the obtaining of analytical results for the electromagnetic field vectors. These results are also valid for linear media. The dependencies are valid also at high speeds of movement. The results of the investigated linear induction system are comparable to those got by the finite elements method. The investigations may be continued in the determination of other characteristics such as drag force, levitation force, etc. The method proposed in this paper for an analysis of linear induction system can be used for optimization calculations. (Author)

  2. 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)

  3. Azimuthal asymmetry in processes of nonlinear QED for linearly polarized photon

    International Nuclear Information System (INIS)

    Bajer, V.N.; Mil'shtejn, A.I.

    1994-01-01

    Cross sections of nonlinear QED processes (photon-photon scattering, photon splitting in a Coulomb field, and Delbrueck scattering) are considered for linearly polarized initial photon. The cross sections have sizeable azimuthal asymmetry. 15 refs.; 3 figs

  4. A Multibeam Dual-Band Orthogonal Linearly Polarized Antenna Array for Satellite Communication on the Move

    Directory of Open Access Journals (Sweden)

    Yi Liu

    2015-01-01

    Full Text Available The design and simulation of a 10 × 8 multibeam dual-band orthogonal linearly polarized antenna array operating at Ku-band are presented for transmit-receive applications. By using patches with different coupling methods as elements, both perpendicular polarization in 12.25–12.75 GHz band and horizontal polarization in 14.0–14.5 GHz band are realized in a shared antenna aperture. A microstrip Rotman lens is employed as the beamforming network with 7 input ports, which can generate a corresponding number of beams to cover −30°–30° with 5 dB beamwidth along one dimension. This type of multibeam orthogonal linearly polarized planar antenna is a good candidate for satellite communication (SatCom.

  5. Precision synchrotron radiation detectors

    International Nuclear Information System (INIS)

    Levi, M.; Rouse, F.; Butler, J.

    1989-03-01

    Precision detectors to measure synchrotron radiation beam positions have been designed and installed as part of beam energy spectrometers at the Stanford Linear Collider (SLC). The distance between pairs of synchrotron radiation beams is measured absolutely to better than 28 /mu/m on a pulse-to-pulse basis. This contributes less than 5 MeV to the error in the measurement of SLC beam energies (approximately 50 GeV). A system of high-resolution video cameras viewing precisely-aligned fiducial wire arrays overlaying phosphorescent screens has achieved this accuracy. Also, detectors of synchrotron radiation using the charge developed by the ejection of Compton-recoil electrons from an array of fine wires are being developed. 4 refs., 5 figs., 1 tab

  6. The impact of Faraday effects on polarized black hole images of Sagittarius A*.

    Science.gov (United States)

    Jiménez-Rosales, Alejandra; Dexter, Jason

    2018-05-01

    We study model images and polarization maps of Sagittarius A* at 230 GHz. We post-process GRMHD simulations and perform a fully relativistic radiative transfer calculation of the emitted synchrotron radiation to obtain polarized images for a range of mass accretion rates and electron temperatures. At low accretion rates, the polarization map traces the underlying toroidal magnetic field geometry. At high accretion rates, we find that Faraday rotation internal to the emission region can depolarize and scramble the map. We measure the net linear polarization fraction and find that high accretion rate "jet-disc" models are heavily depolarized and are therefore disfavoured. We show how Event Horizon Telescope measurements of the polarized "correlation length" over the image provide a model-independent upper limit on the strength of these Faraday effects, and constrain plasma properties like the electron temperature and magnetic field strength.

  7. Sirius synchrotron linear accelerator radiological shields; Blindagens radiológicas do acelerador linear do síncrotron Sirius

    Energy Technology Data Exchange (ETDEWEB)

    Bacchim Neto, F.A.; Rodrigues, A.R.D.; Madacki, R., E-mail: fernando.bacchim@lnls.br [Laboratório Nacional de Luz Síncrotron (LNLS/CNPEM), Campinas, SP (Brazil)

    2017-07-01

    The Brazilian National Synchrotron Light Laboratory (LNLS) is building its second synchrotron light source. Sirius will be the largest and most complex scientific structure in the country and one of the world's first 4{sup th} generation synchrotron light sources. The first of the three Sirius accelerator structures will be a LINAC of 150 MeV. For the development of the radiological shields required throughout the Sirius project, the FLUKA Software based on the Monte-Carlo Method and analytical strategies are used. In the work will be described calculations and preliminary simulations performed during the beam dump project to contain the beam produced by Sirius LINAC.

  8. 77 GHz MEMS antennas on high-resistivity silicon for linear and circular polarization

    KAUST Repository

    Sallam, M. O.

    2011-07-01

    Two new MEMS antennas operating at 77 GHz are presented in this paper. The first antenna is linearly polarized. It possesses a vertical silicon wall that carries a dipole on top of it. The wall is located on top of silicon substrate covered with a ground plane. The other side of the substrate carries a microstrip feeding network in the form of U-turn that causes 180 phase shift. This phase-shifter feeds the arms of the dipole antenna via two vertical Through-Silicon Vias (TSVs) that go through the entire wafer. The second antenna is circularly polarized and formed using two linearly polarized antennas spatially rotated with respect to each other by 90 and excited with 90 phase shift. Both antennas are fabricated using novel process flow on a single high-resistivity silicon wafer via bulk micromachining. Only three processing steps are required to fabricate these antennas. The proposed antennas have appealing characteristics, such as high polarization purity, high gain, and high radiation efficiency. © 2011 IEEE.

  9. Variation of linear and circular polarization persistence for changing field of view and collection area in a forward scattering environment

    Science.gov (United States)

    van der Laan, John D.; Wright, Jeremy B.; Scrymgeour, David A.; Kemme, Shanalyn A.; Dereniak, Eustace L.

    2016-05-01

    We present experimental and simulation results for a laboratory-based forward-scattering environment, where 1 μm diameter polystyrene spheres are suspended in water to model the optical scattering properties of fog. Circular polarization maintains its degree of polarization better than linear polarization as the optical thickness of the scattering environment increases. Both simulation and experiment quantify circular polarization's superior persistence, compared to that of linear polarization, and show that it is much less affected by variations in the field of view and collection area of the optical system. Our experimental environment's lateral extent was physically finite, causing a significant difference between measured and simulated degree of polarization values for incident linearly polarized light, but not for circularly polarized light. Through simulation we demonstrate that circular polarization is less susceptible to the finite environmental extent as well as the collection optic's limiting configuration.

  10. Colloidal InP/ZnS core-shell nanocrystals studied by linearly and circularly polarized photoluminescence

    International Nuclear Information System (INIS)

    Langof, L.; Fradkin, L.; Ehrenfreund, E.; Lifshitz, E.; Micic, O.I.; Nozik, A.J.

    2004-01-01

    The magneto-optical properties of InP/ZnS core-shell nanocrystals (NCs) were investigated by measuring the degree of linear and circular polarization of photoluminescence (PL) spectra, in the presence of an external magnetic field under resonant or non-resonant excitation. The linearly polarized PL data strongly indicate that InP/ZnS NCs have a prolongated shape. The resonant-excited circularly polarized PL decay curves indicate that the spin relaxation time of the studied samples is shorter than the radiative lifetime of their exciton. Furthermore, the magnetic field-induced circularly polarized PL process reveals an exciton g factor (g ex ) of 0.55. Thus, such studies may serve as a tool to directly estimate the NC's shape anisotropy and to determine the g-factor of charge carriers and excitons in those NCs

  11. Colloidal InP/ZnS core shell nanocrystals studied by linearly and circularly polarized photoluminescence

    Science.gov (United States)

    Langof, L.; Fradkin, L.; Ehrenfreund, E.; Lifshitz, E.; Micic, O. I.; Nozik, A. J.

    2004-02-01

    The magneto-optical properties of InP/ZnS core-shell nanocrystals (NCs) were investigated by measuring the degree of linear and circular polarization of photoluminescence (PL) spectra, in the presence of an external magnetic field under resonant or non-resonant excitation. The linearly polarized PL data strongly indicate that InP/ZnS NCs have a prolongated shape. The resonant-excited circularly polarized PL decay curves indicate that the spin relaxation time of the studied samples is shorter than the radiative lifetime of their exciton. Furthermore, the magnetic field-induced circularly polarized PL process reveals an exciton g factor ( gex) of 0.55. Thus, such studies may serve as a tool to directly estimate the NC's shape anisotropy and to determine the g-factor of charge carriers and excitons in those NCs.

  12. Anomalous property of coherent bremsstrahlung linear polarization of relativistic electrons in a crystal

    International Nuclear Information System (INIS)

    Lapko, V.P.; Nasonov, N.N.; Truten', V.I.

    1993-01-01

    Polarization and spectral-and-angular properties of γ-radiation of the relativistic electron flux moving in a crystal under uncorrelated collisions with crystal atomic chains, are studied theoretically. Direction of linear polarization of radiation is shown to vary with energy of emitted photon. Reasons of occurrence of this effect are discussed. The results of numerical calculations demonstrating the possibility to form an intensive source of polarized γ-quanta on the basis of coherent radiation of relativistic electrons during low-angular scattering at crystal atom chains, are given

  13. 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)

  14. CERN: TeV Electron-Positron Linear Collider Studies; More polarization in LEP

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1993-09-15

    The world's highest energy electronpositron collider - CERN's LEP, with a circumference of 27 kilometres - will also be the last such machine to be built as a storage ring. With interest growing in electronpositron physics at energies beyond those attainable at LEP, the next generation of electron-positron colliders must be linear if prohibitive synchrotron radiation power losses are to be avoided. Very high energy linear colliders present many technical challenges but mastery of SLC at Stanford, the world's first electron-positron linear collider, is encouraging. The physics issues of a linear collider have been examined by the international community in ICFA workshops in Saariselka, Finland (September 1991) and most recently in Hawaii (April 1993). The emerging consensus is for a collider with an initial collision energy around 500 GeV, and which can be upgraded to over 1 TeV. A range of very different collider designs are being studied at Laboratories in Europe, the US, Japan and Russia. Following the report of the 1987 CERN Long Range Planning Committee chaired by Carlo Rubbia, studies for a 2 TeV linear collider have progressed at CERN alongside work towards the Laboratory's initial objective - the LHC high energy proton-proton collider in the LEP tunnel.

  15. CERN: TeV Electron-Positron Linear Collider Studies; More polarization in LEP

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    The world's highest energy electronpositron collider - CERN's LEP, with a circumference of 27 kilometres - will also be the last such machine to be built as a storage ring. With interest growing in electronpositron physics at energies beyond those attainable at LEP, the next generation of electron-positron colliders must be linear if prohibitive synchrotron radiation power losses are to be avoided. Very high energy linear colliders present many technical challenges but mastery of SLC at Stanford, the world's first electron-positron linear collider, is encouraging. The physics issues of a linear collider have been examined by the international community in ICFA workshops in Saariselka, Finland (September 1991) and most recently in Hawaii (April 1993). The emerging consensus is for a collider with an initial collision energy around 500 GeV, and which can be upgraded to over 1 TeV. A range of very different collider designs are being studied at Laboratories in Europe, the US, Japan and Russia. Following the report of the 1987 CERN Long Range Planning Committee chaired by Carlo Rubbia, studies for a 2 TeV linear collider have progressed at CERN alongside work towards the Laboratory's initial objective - the LHC high energy proton-proton collider in the LEP tunnel

  16. Colloidal InP/ZnS core-shell nanocrystals studied by linearly and circularly polarized photoluminescence

    Energy Technology Data Exchange (ETDEWEB)

    Langof, L.; Fradkin, L.; Ehrenfreund, E.; Lifshitz, E.; Micic, O.I.; Nozik, A.J

    2004-02-16

    The magneto-optical properties of InP/ZnS core-shell nanocrystals (NCs) were investigated by measuring the degree of linear and circular polarization of photoluminescence (PL) spectra, in the presence of an external magnetic field under resonant or non-resonant excitation. The linearly polarized PL data strongly indicate that InP/ZnS NCs have a prolongated shape. The resonant-excited circularly polarized PL decay curves indicate that the spin relaxation time of the studied samples is shorter than the radiative lifetime of their exciton. Furthermore, the magnetic field-induced circularly polarized PL process reveals an exciton g factor (g{sub ex}) of 0.55. Thus, such studies may serve as a tool to directly estimate the NC's shape anisotropy and to determine the g-factor of charge carriers and excitons in those NCs.

  17. Observations of linear polarization in deep minima of WW Vul

    International Nuclear Information System (INIS)

    Grinin, V.P.; Kiselev, N.N.; Minikulov, N.Kh.; Chernova, G.P.; AN Tadzhikskoj SSR, Dushanbe. Inst. Astrofiziki)

    1988-01-01

    In the course of patrol photometric and polarimetric observations of WW Vul, initiated in 1986 in the Crimea and Sanglok, a broad photometrical minimum was registered, the deepest part of which being composed of three consecutive weakenings of brightness. The increase of linear polarization up to 5-6% (in V band) was observed in each of them. The analysis of the observational data shows, that the main part of polarized light occurs due to scattering of star radiation by dust particles of the circumstellar envelope. the contribution of this polarized radiation increases when the occultation of the star by the opaque dust cloud weakenes the direct (non-polarized) radiation of the star. Additional source of light polarization is the alignement of non-spherical particles in the dust cloud, which are responsible for occultation. Some arguments are given in favor to the idea, that the asymmetry axis of the circumstellar disc - like envelope of WW Vul is oriented parallel to the local interstellar magnetic field. If and alignment of non-spherical particles is caused by magnetic field of the disc, magnetic lines should follow the plane of the disc. The observations confirm the hypothesis, that the source of blue emission, observed in deep minima of such type stars, is the scattered radiation of circumstellar dust

  18. Use of Linear and Circular Polarization: The Secret LCD Screen and 3D Cinema

    Science.gov (United States)

    Richtberg, Stefan; Girwidz, Raimund

    2017-01-01

    References to everyday life are important for teaching physics. Discussing polarization phenomena, liquid crystal displays (LCDs) and 3D cinemas provide such references. In this paper we describe experiments to support students' understanding of linearly polarized light as well as the phenomenon of inverted colors using a secret LCD screen.…

  19. Optics Studies for the CERN Proton Synchrotron Machine Linear and Nonlinear Modelling using Beam Based Measurements

    CERN Document Server

    Cappi, R; Martini, M; Métral, Elias; Métral, G; Steerenberg, R; Müller, A S

    2003-01-01

    The CERN Proton Synchrotron machine is built using combined function magnets. The control of the linear tune as well as the chromaticity in both planes is achieved by means of special coils added to the main magnets, namely two pole-face-windings and one figure-of-eight loop. As a result, the overall magnetic field configuration is rather complex not to mention the saturation effects induced at top-energy. For these reasons a linear model of the PS main magnet does not provide sufficient precision to model particle dynamics. On the other hand, a sophisticated optical model is the key element for the foreseen intensity upgrade and, in particular, for the novel extraction mode based on adiabatic capture of beam particles inside stable islands in transverse phase space. A solution was found by performing accurate measurement of the nonlinear tune as a function of both amplitude and momentum offset so to extract both linear and nonlinear properties of the lattice. In this paper the measurement results are present...

  20. Frequency dependent polarization in blazars

    International Nuclear Information System (INIS)

    Bjoernsson, C.I.

    1984-10-01

    It is argued that the intrinsic frequency dependent polarization in blazars finds its most straightforward explanations in terms of a single rather than a multicomponent sourcemodel. In order to reproduce the observations, under the assumption that the emission mechanism is optically thin synchrotron radiation, both a well ordered magnetic field and an electron distribution with a sharp break or cuttoff are necessary. Non-uniform pitch angle distribution and/or environments where synchrotron losses are important are both conducive to producing strong frequency dependent polarization. Reasons are put forth as to why such conditions ar expected to occur in blazars. Two specific models are discussed in detail and it is shown that they are both able to produce strong frequency dependent polarization, even when the spectral index changes by a small amount only. (orig.)

  1. An L-Band Polarized Electron PWT Photoinjector for the International Linear Collider (ILC)

    CERN Document Server

    Yu, David; Chen Ping; Lundquist, Martin; Luo, Yan; Smirnov, Alexei Yu

    2005-01-01

    A multi-cell, standing-wave, L-band, p-mode, plane-wave-transformer (PWT) photoinjector with an integrated photocathode in a novel linac structure is proposed by DULY Research Inc. as a polarized electron source. The PWT photoinjector is capable of operation in ultra high vacuum and moderate field gradient. Expected performance of an L-band polarized electron PWT injector operating under the parameters for the International Linear Collider is presented. The projected normalized transverse rms emittance is an order of magnitude lower than that produced with a polarized electron dc gun followed by subharmonic bunchers.

  2. 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.

  3. New theoretical results in synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Bagrov, V.G. [Tomsk State University, Lenin Avenue 36, 634050 Tomsk (Russian Federation)]. E-mail: bagrov@phys.tsu.ru; Gitman, D.M. [Instituto de Fisica, Universidade de Sao Paulo, C.P. 66318, 05315-970 Sao Paulo, SP (Brazil); Tlyachev, V.B. [Tomsk Institute of High Current Electronics, Akademicheskiy Avenue 4, Tomsk (Russian Federation); Jarovoi, A.T. [Tomsk State University, Lenin Avenue 36, 634050 Tomsk (Russian Federation)

    2005-11-15

    One of the remarkable features of the relativistic electron synchrotron radiation is its concentration in small angle {delta}{approx}1/{gamma} (here {gamma}-relativistic factor: {gamma}=E/mc{sup 2}, E - energy, m - electron rest mass, c - light velocity) near rotation orbit plane [V.G. Bagrov, V.A. Bordovitsyn, V.G. Bulenok, V. Ya. Epp, Kinematical projection of pulsar synchrotron radiation profiles, in: Proceedings of IV ISTC Scientific Advisory Commitee Seminar on Basic Science in ISTC Aktivities, Akademgorodok, Novosibirsk, April 23-27, 2001, p. 293-300]. This theoretically predicted and experimentally confirmed feature is peculiar to total (spectrum summarized) radiating intensity. This angular distribution property has been supposed to be (at least qualitatively) conserved and for separate spectrum synchrotron radiation components. In the work of V.G. Bagrov, V.A. Bordovitsyn, V. Ch. Zhukovskii, Development of the theory of synchrotron radiation and related processes. Synchrotron source of JINR: the perspective of research, in: The Materials of the Second International Work Conference, Dubna, April 2-6, 2001, pp. 15-30 and in Angular dependence of synchrotron radiation intensity. http://lanl.arXiv.org/abs/physics/0209097, it is shown that the angular distribution of separate synchrotron radiation spectrum components demonstrates directly inverse tendency - the angular distribution deconcentration relatively the orbit plane takes place with electron energy growth. The present work is devoted to detailed investigation of this situation. For exact quantitative estimation of angular concentration degree of synchrotron radiation the definition of radiation effective angle and deviation angle is proposed. For different polarization components of radiation the dependence of introduced characteristics was investigated as a functions of electron energy and number of spectrum component.

  4. Synchrotron oscillation effects on an rf-solenoid spin resonance

    Science.gov (United States)

    Benati, P.; Chiladze, D.; Dietrich, J.; Gaisser, M.; Gebel, R.; Guidoboni, G.; Hejny, V.; Kacharava, A.; Kamerdzhiev, V.; Kulessa, P.; Lehrach, A.; Lenisa, P.; Lorentz, B.; Maier, R.; Mchedlishvili, D.; Morse, W. M.; Öllers, D.; Pesce, A.; Polyanskiy, A.; Prasuhn, D.; Rathmann, F.; Semertzidis, Y. K.; Stephenson, E. J.; Stockhorst, H.; Ströher, H.; Talman, R.; Valdau, Yu.; Weidemann, Ch.; Wüstner, P.

    2012-12-01

    New measurements are reported for the time dependence of the vertical polarization of a 0.97GeV/c deuteron beam circulating in a storage ring and perturbed by an rf solenoid. The storage ring is the cooler synchrotron (COSY) located at the Forschungszentrum Jülich. The beam polarization was measured continuously using a 1.5 cm thick carbon target located at the edge of the circulating deuteron beam and the scintillators of the EDDA detector. An rf solenoid mounted on the ring was used to generate fields at and near the frequency of the 1-Gγ spin resonance. Measurements were made of the vertical beam polarization as a function of time with the operation of the rf solenoid in either fixed or continuously variable frequency mode. Using rf-solenoid strengths as large as 2.66×10-5revolutions/turn, slow oscillations (˜1Hz) were observed in the vertical beam polarization. When the circulating beam was continuously electron cooled, these oscillations completely reversed the polarization and showed no sign of diminishing in amplitude. But for the uncooled beam, the oscillation amplitude was damped to nearly zero within a few seconds. A simple spin-tracking model without the details of the COSY ring lattice was successful in reproducing these oscillations and demonstrating the sensitivity of the damping to the magnitude of the synchrotron motion of the beam particles. The model demonstrates that the characteristic features of measurements made in the presence of large synchrotron oscillations are distinct from the features of such measurements when made off resonance. These data were collected in preparation for a study of the spin coherence time, a beam property that needs to become long to enable a search for an electric dipole moment using a storage ring.

  5. Pump-probe experiments in atoms involving laser and synchrotron radiation: an overview

    International Nuclear Information System (INIS)

    Wuilleumier, F J; Meyer, M

    2006-01-01

    The combined use of laser and synchrotron radiations for atomic photoionization studies started in the early 1980s. The strong potential of these pump-probe experiments to gain information on excited atomic states is illustrated through some exemplary studies. The first series of experiments carried out with the early synchrotron sources, from 1960 to about 1995, are reviewed, including photoionization of unpolarized and polarized excited atoms, and time-resolved laser-synchrotron studies. With the most advanced generation of synchrotron sources, a whole new class of pump-probe experiments benefiting from the high brightness of the new synchrotron beams has been developed since 1996. A detailed review of these studies as well as possible future applications of pump-probe experiments using third generation synchrotron sources and free electron lasers is presented. (topical review)

  6. Calibration of the degree of linear polarization measurements of the polarized Sun-sky radiometer based on the POLBOX system.

    Science.gov (United States)

    Li, Zhengqiang; Li, Kaitao; Li, Li; Xu, Hua; Xie, Yisong; Ma, Yan; Li, Donghui; Goloub, Philippe; Yuan, Yinlin; Zheng, Xiaobing

    2018-02-10

    Polarization observation of sky radiation is the frontier approach to improve the remote sensing of atmospheric components, e.g., aerosol and clouds. The polarization calibration of the ground-based Sun-sky radiometer is the basis for obtaining accurate degree of linear polarization (DOLP) measurement. In this paper, a DOLP calibration method based on a laboratory polarized light source (POLBOX) is introduced in detail. Combined with the CE318-DP Sun-sky polarized radiometer, a calibration scheme for DOLP measurement is established for the spectral range of 440-1640 nm. Based on the calibration results of the Sun-sky radiometer observation network, the polarization calibration coefficient and the DOLP calibration residual are analyzed statistically. The results show that the DOLP residual of the calibration scheme is about 0.0012, and thus it can be estimated that the final DOLP calibration accuracy of this method is about 0.005. Finally, it is verified that the accuracy of the calibration results is in accordance with the expected results by comparing the simulated DOLP with the vector radiative transfer calculations.

  7. Stable Single Polarization, Single Frequency, and Linear Cavity Er-Doped Fiber Laser Using a Saturable Absorber

    International Nuclear Information System (INIS)

    Li Qi; Yan Feng-Ping; Peng Wan-Jing; Feng Su-Chun; Feng Ting; Tan Si-Yu; Liu Peng

    2013-01-01

    A simple approach for stable single polarization, single frequency, and linear cavity erbium doped fiber laser is proposed and demonstrated. A Fabry—Pérot filter, polarizer and saturable absorber are used together to ensure stable single frequency, single polarization operation. The optical signal-to-noise ratio of the laser is approximately 57 dB, and the Lorentz linewidth is 13.9 kHz. The polarization state of the laser with good stability is confirmed and the degree of polarization is >99%

  8. A STUDY OF RADIO POLARIZATION IN PROTOSTELLAR JETS

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-01-10

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

  9. X-ray energy-dispersive diffractometry using synchrotron radiation

    International Nuclear Information System (INIS)

    Buras, B.; Staun Olsen, J.; Gerward, L.

    1977-03-01

    In contrast to bremsstrahlung from X-ray tubes, synchrotron radiation is very intense, has a smooth spectrum, its polarization is well defined, and at DESY the range of useful photon energies can be extended to about 70 keV and higher. In addition the X-ray beam is very well collimated. Thus synchrotron radiation seems to be an ideal X-ray source for energy-dispersive diffractometry. This note briefly describes the experimental set up at DESY, shows examples of results, and presents the underlying 'philosophy' of the research programme. (Auth.)

  10. Joint polarization tracking and channel equalization based on radius-directed linear Kalman filter

    Science.gov (United States)

    Zhang, Qun; Yang, Yanfu; Zhong, Kangping; Liu, Jie; Wu, Xiong; Yao, Yong

    2018-01-01

    We propose a joint polarization tracking and channel equalization scheme based on radius-directed linear Kalman filter (RD-LKF) by introducing the butterfly finite-impulse-response (FIR) filter in our previously proposed RD-LKF method. Along with the fast polarization tracking, it can also simultaneously compensate the inter-symbol interference (ISI) effects including residual chromatic dispersion and polarization mode dispersion. Compared with the conventional radius-directed equalizer (RDE) algorithm, it is demonstrated experimentally that three times faster convergence speed, one order of magnitude better tracking capability, and better BER performance is obtained in polarization division multiplexing 16 quadrature amplitude modulation system. Besides, the influences of the algorithm parameters on the convergence and the tracking performance are investigated by numerical simulation.

  11. Polarization holograms in a bifunctional amorphous polymer exhibiting equal values of photoinduced linear and circular birefringences.

    Science.gov (United States)

    Provenzano, Clementina; Pagliusi, Pasquale; Cipparrone, Gabriella; Royes, Jorge; Piñol, Milagros; Oriol, Luis

    2014-10-09

    Light-controlled molecular alignment is a flexible and useful strategy introducing novelty in the fields of mechanics, self-organized structuring, mass transport, optics, and photonics and addressing the development of smart optical devices. Azobenzene-containing polymers are well-known photocontrollable materials with large and reversible photoinduced optical anisotropies. The vectorial holography applied to these materials enables peculiar optical devices whose properties strongly depend on the relative values of the photoinduced birefringences. Here is reported a polarization holographic recording based on the interference of two waves with orthogonal linear polarization on a bifunctional amorphous polymer that, exceptionally, exhibits equal values of linear and circular birefringence. The peculiar photoresponse of the material coupled with the holographic technique demonstrates an optical device capable of decomposing the light into a set of orthogonally polarized linear components. The holographic structures are theoretically described by the Jones matrices method and experimentally investigated.

  12. Optically-driven red blood cell rotor in linearly polarized laser tweezers

    Indian Academy of Sciences (India)

    We have constructed a dual trap optical tweezers set-up around an inverted microscope where both the traps can be independently controlled and manipulated in all the three dimensions. Here we report our observations on rotation of red blood cells (RBCs) in a linearly polarized optical trap. Red blood cells deform and ...

  13. Photoelectron linear accelerator for producing a low emittance polarized electron beam

    Science.gov (United States)

    Yu, David U.; Clendenin, James E.; Kirby, Robert E.

    2004-06-01

    A photoelectron linear accelerator for producing a low emittance polarized electric beam. The accelerator includes a tube having an inner wall, the inner tube wall being coated by a getter material. A portable, or demountable, cathode plug is mounted within said tube, the surface of said cathode having a semiconductor material formed thereon.

  14. Relations between broad-band linear polarization and Ca II H and K emission in late-type dwarf stars

    Science.gov (United States)

    Huovelin, Juhani; Saar, Steven H.; Tuominen, Ilkka

    1988-01-01

    Broadband UBV linear polarization data acquired for a sample of late-type dwarfs are compared with contemporaneous measurements of Ca II H and K line core emission. A weighted average of the largest values of the polarization degree is shown to be the best parameter for chromospheric activity diagnosis. The average maximum polarization in the UV is found to increase from late-F to late-G stars. It is noted that polarization in the U band is considerably more sensitive to activity variations than that in the B or V bands. The results indicate that stellar magnetic fields and the resulting saturation in the Zeeman-sensitive absorption lines are the most probably source of linear polarization in late-type main-sequence stars.

  15. Effective spectrum width of the synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Bagrov, V. G., E-mail: bagrov@phys.tsu.ru [Department of Physics, Tomsk State University, Tomsk (Russian Federation); Institute of High Current Electronics, SB RAS, Tomsk (Russian Federation); Gitman, D. M., E-mail: gitman@if.usp.br [Department of Physics, Tomsk State University, Tomsk (Russian Federation); Institute of Physics, University of São Paulo, São Paulo (Brazil); P.N.Lebedev Physical Institute, Moscow (Russian Federation); Levin, A. D., E-mail: alevin@if.usp.br [Institute of Physics, University of São Paulo, São Paulo (Brazil); Loginov, A. S.; Saprykin, A. D. [Department of Physics, Tomsk State University, Tomsk (Russian Federation)

    2015-11-25

    For an exact quantitative description of spectral properties of synchrotron radiation (SR), the concept of effective width of the spectrum is introduced. In the most interesting case, which corresponds to the ultrarelativistic limit of SR, the effective width of the spectrum is calculated for the polarization components, and new physically important quantitative information on the structure of spectral distributions is obtained. For the first time, the spectral distribution for the circular polarization component of the SR for the upper half-space is obtained within classical theory.

  16. Effective spectrum width of the synchrotron radiation

    International Nuclear Information System (INIS)

    Bagrov, V. G.; Gitman, D. M.; Levin, A. D.; Loginov, A. S.; Saprykin, A. D.

    2015-01-01

    For an exact quantitative description of spectral properties of synchrotron radiation (SR), the concept of effective width of the spectrum is introduced. In the most interesting case, which corresponds to the ultrarelativistic limit of SR, the effective width of the spectrum is calculated for the polarization components, and new physically important quantitative information on the structure of spectral distributions is obtained. For the first time, the spectral distribution for the circular polarization component of the SR for the upper half-space is obtained within classical theory

  17. Effective spectrum width of the synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Bagrov, V.G. [Tomsk State University, Department of Physics, Tomsk (Russian Federation); SB RAS, Institute of High Current Electronics, Tomsk (Russian Federation); Gitman, D.M. [Tomsk State University, Department of Physics, Tomsk (Russian Federation); University of Sao Paulo, Institute of Physics, Sao Paulo (Brazil); P.N. Lebedev Physical Institute, Moscow (Russian Federation); Levin, A.D. [University of Sao Paulo, Institute of Physics, Sao Paulo (Brazil); Loginov, A.S.; Saprykin, A.D. [Tomsk State University, Department of Physics, Tomsk (Russian Federation)

    2015-11-15

    For an exact quantitative description of spectral properties of synchrotron radiation (SR), the concept of effective width of the spectrum is introduced. In the most interesting case, which corresponds to the ultrarelativistic limit of SR, the effective width of the spectrum is calculated for the polarization components, and new physically important quantitative information on the structure of spectral distributions is obtained. For the first time, the spectral distribution for the circular polarization component of the SR for the upper half-space is obtained within classical theory. (orig.)

  18. Direct generation of linearly polarized single photons with a deterministic axis in quantum dots

    Directory of Open Access Journals (Sweden)

    Wang Tong

    2017-07-01

    Full Text Available We report the direct generation of linearly polarized single photons with a deterministic polarization axis in self-assembled quantum dots (QDs, achieved by the use of non-polar InGaN without complex device geometry engineering. Here, we present a comprehensive investigation of the polarization properties of these QDs and their origin with statistically significant experimental data and rigorous k·p modeling. The experimental study of 180 individual QDs allows us to compute an average polarization degree of 0.90, with a standard deviation of only 0.08. When coupled with theoretical insights, we show that these QDs are highly insensitive to size differences, shape anisotropies, and material content variations. Furthermore, 91% of the studied QDs exhibit a polarization axis along the crystal [1–100] axis, with the other 9% polarized orthogonal to this direction. These features give non-polar InGaN QDs unique advantages in polarization control over other materials, such as conventional polar nitride, InAs, or CdSe QDs. Hence, the ability to generate single photons with polarization control makes non-polar InGaN QDs highly attractive for quantum cryptography protocols.

  19. Direct generation of linearly polarized single photons with a deterministic axis in quantum dots

    Science.gov (United States)

    Wang, Tong; Puchtler, Tim J.; Patra, Saroj K.; Zhu, Tongtong; Ali, Muhammad; Badcock, Tom J.; Ding, Tao; Oliver, Rachel A.; Schulz, Stefan; Taylor, Robert A.

    2017-07-01

    We report the direct generation of linearly polarized single photons with a deterministic polarization axis in self-assembled quantum dots (QDs), achieved by the use of non-polar InGaN without complex device geometry engineering. Here, we present a comprehensive investigation of the polarization properties of these QDs and their origin with statistically significant experimental data and rigorous k·p modeling. The experimental study of 180 individual QDs allows us to compute an average polarization degree of 0.90, with a standard deviation of only 0.08. When coupled with theoretical insights, we show that these QDs are highly insensitive to size differences, shape anisotropies, and material content variations. Furthermore, 91% of the studied QDs exhibit a polarization axis along the crystal [1-100] axis, with the other 9% polarized orthogonal to this direction. These features give non-polar InGaN QDs unique advantages in polarization control over other materials, such as conventional polar nitride, InAs, or CdSe QDs. Hence, the ability to generate single photons with polarization control makes non-polar InGaN QDs highly attractive for quantum cryptography protocols.

  20. Limitations of heavy ion synchrotron acceleration for inertial fusion

    International Nuclear Information System (INIS)

    Berley, D.; Danby, G.T.

    1977-01-01

    The potential benefits from heavy ion inertial fusion motivate the rapid development of a program to test the principle. To define the program, accelerator parameters which have not hitherto been commonly considered must be studied interactively with basic questions of space charge limitations and charge exchange. Beam lifetime and power output efficiency may ultimately lead to a linear accelerator as the choice for an ignition device. For proof of principle, however, at power levels way beyond present inertial fusion experience, synchrotrons may have applicability at lower cost. The power and energy which can be delivered by the accelerating system to the reaction chamber are limited by space charge defocussing and intra beam charge exchange scattering, both of which are beam density dependent. These put constraints on linac injector energy, synchrotron aperture, synchrotron magnetic rigidity, acceleration time, ion species and charge to mass ratio. The accelerator system considered is classical. A linear accelerator injects into a synchrotron which accelerates the ion beam to the full energy delivered to the target. The maximum energy deliverable by a synchrotron is treated in section I. The targetting parameters and the energy gained through synchrotron acceleration completely determine the synchrotron aperture. These are discussed in sections II and III. The ion range in material is treated in section IV. The problem of intrabeam scattering is considered in section V. Finally, in section VI is a discussion of examples to meet specified goals

  1. Synchrotron based spallation neutron source concepts

    International Nuclear Information System (INIS)

    Cho, Y.

    1998-01-01

    During the past 20 years, rapid-cycling synchrotrons (RCS) have been used very productively to generate short-pulse thermal neutron beams for neutron scattering research by materials science communities in Japan (KENS), the UK (ISIS) and the US (IPNS). The most powerful source in existence, ISIS in the UK, delivers a 160-kW proton beam to a neutron-generating target. Several recently proposed facilities require proton beams in the MW range to produce intense short-pulse neutron beams. In some proposals, a linear accelerator provides the beam power and an accumulator ring compresses the pulse length to the required ∼ 1 micros. In others, RCS technology provides the bulk of the beam power and compresses the pulse length. Some synchrotron-based proposals achieve the desired beam power by combining two or more synchrotrons of the same energy, and others propose a combination of lower and higher energy synchrotrons. This paper presents the rationale for using RCS technology, and a discussion of the advantages and disadvantages of synchrotron-based spallation sources

  2. POLARIZED BEAMS: 2 - Partial Siberian Snake rescues polarized protons at Brookhaven

    International Nuclear Information System (INIS)

    Huang, Haixin

    1994-01-01

    To boost the level of beam polarization (spin orientation), a partial 'Siberian Snake' was recently used to overcome imperfection depolarizing resonances in the Brookhaven Alternating Gradient Synchrotron (AGS). This 9-degree spin rotator recently permitted acceleration with no noticeable polarization loss. The intrinsic AGS depolarizing resonances (which degrade the polarization content) had been eliminated by betatron tune jumps, but the imperfection resonances were compensated by means of harmonic orbit corrections. However, at high energies these orbit corrections are difficult and tedious and a Siberian Snake became an attractive alternative

  3. MAPPING THE LINEARLY POLARIZED SPECTRAL LINE EMISSION AROUND THE EVOLVED STAR IRC+10216

    Energy Technology Data Exchange (ETDEWEB)

    Girart, J. M. [Institut de Ciencies de l' Espai, (CSIC-IEEC), Campus UAB, Facultat de Ciencies, C5p 2, 08193 Bellaterra, Catalunya (Spain); Patel, N. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Vlemmings, W. H. T. [Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, SE-439 92 Onsala (Sweden); Rao, Ramprasad, E-mail: girart@ice.cat [Submillimeter Array, Academia Sinica Institute of Astronomy and Astrophysics, 645 N. Aohoku Place, Hilo, HI 96720 (United States)

    2012-05-20

    We present spectro-polarimetric observations of several molecular lines obtained with the Submillimeter Array toward the carbon-rich asymptotic giant branch star IRC+10216. We have detected and mapped the linear polarization of the CO 3-2, SiS 19-18, and CS 7-6 lines. The polarization arises at a distance of {approx_equal} 450 AU from the star and is blueshifted with respect to the Stokes I. The SiS 19-18 polarization pattern appears to be consistent with a locally radial magnetic field configuration. However, the CO 3-2 and CS 7-6 line polarization suggests an overall complex magnetic field morphology within the envelope. This work demonstrates the feasibility of using spectro-polarimetric observations to carry out tomographic imaging of the magnetic field in circumstellar envelopes.

  4. 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

  5. Source finding in linear polarization for LOFAR, and SKA predecessor surveys, using Faraday moments

    Science.gov (United States)

    Farnes, J. S.; Heald, G.; Junklewitz, H.; Mulcahy, D. D.; Haverkorn, M.; Van Eck, C. L.; Riseley, C. J.; Brentjens, M.; Horellou, C.; Vacca, V.; Jones, D. I.; Horneffer, A.; Paladino, R.

    2018-03-01

    The optimal source-finding strategy for linear polarization data is an unsolved problem, with many inhibitive factors imposed by the technically challenging nature of polarization observations. Such an algorithm is essential for Square Kilometre Array (SKA) pathfinder surveys, such as the Multifrequency Snapshot Sky Survey with the LOw Frequency ARray (LOFAR), as data volumes are significant enough to prohibit manual inspection. We present a new strategy of `Faraday Moments' for source-finding in linear polarization with LOFAR, using the moments of the frequency-dependent full-Stokes data (i.e. the mean, standard deviation, skewness, and excess kurtosis). Through simulations of the sky, we find that moments can identify polarized sources with a high completeness: 98.5 per cent at a signal to noise of 5. While the method has low reliability, rotation measure (RM) synthesis can be applied per candidate source to filter out instrumental and spurious detections. This combined strategy will result in a complete and reliable catalogue of polarized sources that includes the full sensitivity of the observational bandwidth. We find that the technique can reduce the number of pixels on which RM Synthesis needs to be performed by a factor of ≈1 × 105 for source distributions anticipated with modern radio telescopes. Through tests on LOFAR data, we find that the technique works effectively in the presence of diffuse emission. Extensions of this method are directly applicable to other upcoming radio surveys such as the POlarization Sky Survey of the Universe's Magnetism with the Australia Square Kilometre Array Pathfinder, and the SKA itself.

  6. Polarization of photoelectrons produced from atoms by synchrotron radiation

    International Nuclear Information System (INIS)

    Hughes, V.W.; Lu, D.C.; Huang, K.N.

    1981-01-01

    The polarization of photoelectrons from stoms has proved to be an important tool for studying correlation effects in atoms, as well as relativistic effects such as the spin-orbit interaction. Extensive experimental and theoretical studies have been made of the Fano effect, which is the production of polarized electrons by photoionization of unpolarized atoms by circularly polarized light. The experiments have dealt mostly with alkali atoms and with photon energies slightly above the ionization thresholds. Measurements that could be made to utilize polarized radiation are discussed

  7. Mitigating of modal instabilities in linearly-polarized fiber amplifiers by shifting pump wavelength

    International Nuclear Information System (INIS)

    Tao, Rumao; Ma, Pengfei; Wang, Xiaolin; Zhou, Pu; Liu, Zejin

    2015-01-01

    We investigated the effect of pump wavelength on the modal instabilities (MI) in high-power linearly polarized Yb-doped fiber amplifiers. We built a novel semi-analytical model to determine the frequency coupling characteristics and power threshold of MI, which indicates promising MI suppression through pumping at an appropriate wavelength. By pumping at 915 nm, the threshold can be enhanced by a factor of 2.1 as compared to that pumped at 976 nm. Based on a high-power linearly polarized fiber amplifier platform, we studied the influence of pump wavelength experimentally. A maximal enhancement factor of 1.9 has been achieved when pumped at 915 nm, which agrees with the theoretical calculation and verified our theoretical model. Furthermore, we show that MI suppression by detuning the pump wavelength is weakened for fiber with a large core-to-cladding ratio. (paper)

  8. 20 GeV e+ x 400 GeV p: some synchrotron radiation considerations

    International Nuclear Information System (INIS)

    Humphrey, J.W.; Limon, P.J.

    1977-01-01

    The possibility of a 20 GeV electron ring in the 400 x 400 GeV 2 ISABELLE tunnel is considered. The conclusions that can be drawn from these considerations are: (1) much work remains to be done on the implications of synchrotron radiation for insertion design; (2) in the absence of considerations concerning insertion areas with longitudinal polarization, placing the electron ring in the same vertical plane as the electron ring is mildly favored; (3) creating insertions for longitudinally polarized electrons is difficult, and elementary considerations indicate that the synchrotron radiation flux in the insertion region will increase by a factor of approximately 100 and the luminosity may decrease by a factor of approximately 10; and (4) the creation of insertions for longitudinally polarized electrons favors placing the electron ring in the same horizontal plane as the proton ring

  9. MICROANALYSIS OF MATERIALS USING SYNCHROTRON RADIATION.

    Energy Technology Data Exchange (ETDEWEB)

    JONES,K.W.; FENG,H.

    2000-12-01

    High intensity synchrotron radiation produces photons with wavelengths that extend from the infrared to hard x rays with energies of hundreds of keV with uniquely high photon intensities that can be used to determine the composition and properties of materials using a variety of techniques. Most of these techniques represent extensions of earlier work performed with ordinary tube-type x-ray sources. The properties of the synchrotron source such as the continuous range of energy, high degree of photon polarization, pulsed beams, and photon flux many orders of magnitude higher than from x-ray tubes have made possible major advances in the possible chemical applications. We describe here ways that materials analyses can be made using the high intensity beams for measurements with small beam sizes and/or high detection sensitivity. The relevant characteristics of synchrotron x-ray sources are briefly summarized to give an idea of the x-ray parameters to be exploited. The experimental techniques considered include x-ray fluorescence, absorption, and diffraction. Examples of typical experimental apparatus used in these experiments are considered together with descriptions of actual applications.

  10. Polarized atomic orbitals for linear scaling methods

    Science.gov (United States)

    Berghold, Gerd; Parrinello, Michele; Hutter, Jürg

    2002-02-01

    We present a modified version of the polarized atomic orbital (PAO) method [M. S. Lee and M. Head-Gordon, J. Chem. Phys. 107, 9085 (1997)] to construct minimal basis sets optimized in the molecular environment. The minimal basis set derives its flexibility from the fact that it is formed as a linear combination of a larger set of atomic orbitals. This approach significantly reduces the number of independent variables to be determined during a calculation, while retaining most of the essential chemistry resulting from the admixture of higher angular momentum functions. Furthermore, we combine the PAO method with linear scaling algorithms. We use the Chebyshev polynomial expansion method, the conjugate gradient density matrix search, and the canonical purification of the density matrix. The combined scheme overcomes one of the major drawbacks of standard approaches for large nonorthogonal basis sets, namely numerical instabilities resulting from ill-conditioned overlap matrices. We find that the condition number of the PAO overlap matrix is independent from the condition number of the underlying extended basis set, and consequently no numerical instabilities are encountered. Various applications are shown to confirm this conclusion and to compare the performance of the PAO method with extended basis-set calculations.

  11. 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.

  12. The high peak current polarized electron source of the Stanford Linear Collider

    International Nuclear Information System (INIS)

    Schultz, D.; Alley, R.; Aoyagi, H.; Clendenin, J.; Frisch, J.; Garden, C.; Hoyt, E.; Kirby, R.; Klaisner, L.; Kulikov, A.; Mulhollan, G.; Prescott, C.; Saez, P.; Tang, H.; Turner, J.; Woods, M.; Yeremian, D.; Zolotorev, M.

    1994-01-01

    The Stanford Linear Collider injector requires two 2 ns pulses of 4.5-5.5 x 10 10 electrons, separated by 61 ns at 120 Hz, from its source. Since 1992, these currents have been provided by a polarized electron source based on GaAs photocathodes. A beam polarization of 76±4% has been measured at the end of the 50 GeV linac. At low photocathode quantum efficiencies, and for excitation near threshold, the maximum current delivered by the source is constrained, not by the space charge limit of the gun, but by a ''charge limit'' of the photocathode. The charge limited current is proportional to the photocathode quantum efficiency, but the proportionality varies for different photocathode types. Experience with high polarization strained GaAs photocathodes on a test beamline and on the SLC is presented. (orig.)

  13. Coherent Synchrotron Radiation A Simulation Code Based on the Non-Linear Extension of the Operator Splitting Method

    CERN Document Server

    Dattoli, Giuseppe

    2005-01-01

    The coherent synchrotron radiation (CSR) is one of the main problems limiting the performance of high intensity electron accelerators. A code devoted to the analysis of this type of problems should be fast and reliable: conditions that are usually hardly achieved at the same time. In the past, codes based on Lie algebraic techniques have been very efficient to treat transport problem in accelerators. The extension of these method to the non-linear case is ideally suited to treat CSR instability problems. We report on the development of a numerical code, based on the solution of the Vlasov equation, with the inclusion of non-linear contribution due to wake field effects. The proposed solution method exploits an algebraic technique, using exponential operators implemented numerically in C++. We show that the integration procedure is capable of reproducing the onset of an instability and effects associated with bunching mechanisms leading to the growth of the instability itself. In addition, parametric studies a...

  14. Multiply charged negative ions of hydrogen in linearly polarized laser fields

    International Nuclear Information System (INIS)

    van Duijn, E.; Muller, H.G.

    1997-01-01

    Motivated by the prediction of the appearance of atomic multiply charged negative ions (AMCNI) of hydrogen, induced by a linearly polarized laser field, we present an analytical quantum mechanical treatment of the appearance and structure of AMCNI in a linearly polarized field, based on high-frequency Floquet theory (HFFT). For the simplest AMCNI of hydrogen, H 2- and H 3- , the values of α 0 at which the first bound state appears are α 0 =1.62x10 2 and α 0 =1.02x10 4 , where α 0 =I 1/2 /ω 2 is the amplitude of the oscillation of a free electron in the field with frequency ω and intensity I (unless stated otherwise, we use atomic units throughout this paper). Whereas in vacuum at least one of the electrons of an AMCNI autodetaches, an intense high-frequency field can change the character of the ion dramatically, such that bound states of AMCNI can appear. Due to the interaction with the field, the electrons of the AMCNI oscillate in phase along the polarization axis. This open-quotes quiverclose quotes motion enables the electrons to be spatially separated over distances of order α 0 , reducing the repulsive e-e interaction as α 0 increases. In other words, for α 0 large enough, the field enables a configuration in which the electrons, while widely separated, are bound to one proton. For the prediction of bound states of H N- with N>3, however, a relativistic description or low-frequency theory is required. copyright 1997 The American Physical Society

  15. Circularly polarized light to study linear magneto-optics for ferrofluids: θ-scan technique

    Science.gov (United States)

    Meng, Xiangshen; Huang, Yan; He, Zhenghong; Lin, Yueqiang; Liu, Xiaodong; Li, Decai; Li, Jian; Qiu, Xiaoyan

    2018-06-01

    Circularly polarized light can be divided into two vertically linearly polarized light beams with  ±π/2 phase differences. In the presence of an external magnetic field, when circularly polarized light travels through a ferrofluid film, whose thickness is no more than that of λ/4 plate, magneto-optical, magnetic birefringence and dichroism effects cause the transmitted light to behave as elliptically polarized light. Using angular scan by a continuously rotating polarizer as analyzer, the angular (θ) distribution curve of relative intensity (T) corresponding to elliptically polarized light can be measured. From the T  ‑  θ curve having ellipsometry, the parameters such as the ratio of short to long axis, and angular orientation of the long axis to the vertical field direction can be obtained. Thus, magnetic birefringence and dichroism can be probed simultaneously by measuring magneto-optical, positive or negative birefringence and dichroism features from the transmission mode. The proposed method is called θ-scan technique, and can accurately determine sample stability, magnetic field direction, and cancel intrinsic light source ellipticity. This study may be helpful to further research done to ferrofluids and other similar colloidal samples with anisotropic optics.

  16. Feasibility of maintaining in-plane polarization for a storage ring EDM search

    Science.gov (United States)

    Stephenson, Edward; Storage Ring EDM Collaboration

    2014-09-01

    A search for an electric dipole moment (EDM) on charged particles using a storage ring requires beam polarization lifetimes approaching 1000 s for in-plane polarization. A feasibility study using beam bunching and sextupole field adjustment is underway with a 0.97-GeV/c vector-polarized deuteron beam at COSY. The polarimeter consists of a thick carbon target positioned at the edge of the beam and the EDDA scintillation detectors. The DAQ system assigns a clock time to each polarimeter event. Once calibrated against the RF-cavity, the clock time is used to select events associated with a maximal sideways polarization (precessing at 120 kHz). With this tool, the in-plane polarization magnitude is tracked versus time. Electron cooling reduces the depolarization from finite emittance and second-order momentum spread acting through synchrotron oscillations. Further lifetime improvement to the level of hundreds of seconds is achieved by adjusting sextupole fields located in the COSY ring arcs at places of large transverse beta functions and dispersion. The dependence of the reciprocal of the lifetime on sextupole field strength is nearly linear, permitting an easy location of the best field values. These typically occur near loci of zero chromaticity. A search for an electric dipole moment (EDM) on charged particles using a storage ring requires beam polarization lifetimes approaching 1000 s for in-plane polarization. A feasibility study using beam bunching and sextupole field adjustment is underway with a 0.97-GeV/c vector-polarized deuteron beam at COSY. The polarimeter consists of a thick carbon target positioned at the edge of the beam and the EDDA scintillation detectors. The DAQ system assigns a clock time to each polarimeter event. Once calibrated against the RF-cavity, the clock time is used to select events associated with a maximal sideways polarization (precessing at 120 kHz). With this tool, the in-plane polarization magnitude is tracked versus time. Electron

  17. OBSERVATIONS OF LINEAR POLARIZATION IN A SOLAR CORONAL LOOP PROMINENCE SYSTEM OBSERVED NEAR 6173 Å

    Energy Technology Data Exchange (ETDEWEB)

    Saint-Hilaire, Pascal; Martínez Oliveros, Juan-Carlos; Hudson, Hugh S.; Krucker, Säm; Bain, Hazel [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Schou, Jesper [Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, D-37077 Göttingen (Germany); Couvidat, Sébastien, E-mail: shilaire@ssl.berkeley.edu [W. W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305 (United States)

    2014-05-10

    White-light observations by the Solar Dynamics Observatory's Helioseismic and Magnetic Imager of a loop-prominence system occurring in the aftermath of an X-class flare on 2013 May 13 near the eastern solar limb show a linearly polarized component, reaching up to ∼20% at an altitude of ∼33 Mm, about the maximum amount expected if the emission were due solely to Thomson scattering of photospheric light by the coronal material. The mass associated with the polarized component was 8.2 × 10{sup 14} g. At 15 Mm altitude, the brightest part of the loop was 3(±0.5)% linearly polarized, only about 20% of that expected from pure Thomson scattering, indicating the presence of an additional unpolarized component at wavelengths near Fe I (617.33 nm). We estimate the free electron density of the white-light loop system to possibly be as high as 1.8 × 10{sup 12} cm{sup –3}.

  18. Applications of first order matricial theory to the calculation of storage ring designed for producing synchrotron radiation

    International Nuclear Information System (INIS)

    Machado, J.M.

    1984-01-01

    A review of first order matrix theory (linear approximation) used for calculating component elements of a particle accelerator employing the synchrotron principle of alternated gradient, is presented. Based on this theory, criteria for dimensioning synchrotron designed, exclusively for producing electromagnetic radiation, are established. The problem to find out optimum disposition of elements (straight line sections, quadrupolar magnetic lens, etc.) which take advantages of deflector magnets of the DCI synchrotron (Orsay Linear Accelerator Laboratory, French) aiming to construct a synchrotron designed to operate as electromagnetic radiation source, is solved. (M.C.K.) [pt

  19. Unique heavy lepton signature at e+e- linear collider with polarized beams

    International Nuclear Information System (INIS)

    Moortgat-Pick, G.; Osland, P.; Pankov, A.A.; Tsytrinov, A.V.

    2013-03-01

    We explore the effects of neutrino and electron mixing with exotic heavy leptons in the process e + e - →W + W - within E 6 models. We examine the possibility of uniquely distinguishing and identifying such effects of heavy neutral lepton exchange from Z-Z' mixing within the same class of models and also from analogous ones due to competitor models with anomalous trilinear gauge couplings (AGC) that can lead to very similar experimental signatures at the e + e - International Linear Collider (ILC) for √(s)=350, 500 GeV and 1 TeV. Such clear identification of the model is possible by using a certain double polarization asymmetry. The availability of both beams being polarized plays a crucial role in identifying such exotic-lepton admixture. In addition, the sensitivity of the ILC for probing exotic-lepton admixture is substantially enhanced when the polarization of the produced W ± bosons is considered.

  20. High energy polarized electron beams

    International Nuclear Information System (INIS)

    Rossmanith, R.

    1987-01-01

    In nearly all high energy electron storage rings the effect of beam polarization by synchrotron radiation has been measured. The buildup time for polarization in storage rings is of the order of 10 6 to 10 7 revolutions; the spins must remain aligned over this time in order to avoid depolarization. Even extremely small spin deviations per revolution can add up and cause depolarization. The injection and the acceleration of polarized electrons in linacs is much easier. Although some improvements are still necessary, reliable polarized electron sources with sufficiently high intensity and polarization are available. With the linac-type machines SLC at Stanford and CEBAF in Virginia, experiments with polarized electrons will be possible

  1. Synchrotron radiation in atomic physics

    International Nuclear Information System (INIS)

    Crasemann, B.

    1998-01-01

    Much of present understanding of atomic and molecular structure and dynamics was gained through studies of photon-atom interactions. In particular, observations of the emission, absorption, and scattering of X rays have complemented particle-collision experiments in elucidating the physics of atomic inner shells. Grounded on Max von Laue's theoretical insight and the invention of the Bragg spectrometer, the field's potential underwent a step function with the development of synchrotron-radiation sources. Notably current third-generation sources have opened new horizons in atomic and molecular physics by producing radiation of wide tunability and exceedingly high intensity and polarization, narrow energy bandwidth, and sharp time structure. In this review, recent advances in synchrotron-radiation studies in atomic and molecular science are outlined. Some tempting opportunities are surveyed that arise for future studies of atomic processes, including many-body effects, aspects of fundamental photon-atom interactions, and relativistic and quantum-electrodynamic phenomena. (author)

  2. Orthogonal linear polarization tunable-beat ring laser with a superluminescent diode

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Y.; Yoshino, T. [Department of Electronic Engineering, Faculty of Engineering, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376 (Japan)

    1997-09-01

    An orthogonal linear polarization operated ring laser with a superluminescent diode has been demonstrated to generate a tunable optical beat signal. The ring cavity contains a superluminescent diode as the optical gain medium, Faraday rotators, and a variable phase retarder (Babinet-Soleil compensator). By controlling the retarder, we changed the beat frequency in the range from a few tens of megahertz to 100 MHz. {copyright} 1997 Optical Society of America

  3. B-mode contamination by synchrotron emission from 3-yr Wilkinson Microwave Anisotropy Probe data

    NARCIS (Netherlands)

    Carretti, E.; Bernardi, G.; Cortiglioni, S.

    2006-01-01

    We study the contamination of the B-mode of the cosmic microwave background polarization (CMBP) by Galactic synchrotron in the lowest emission regions of the sky. The 22.8-GHz polarization map of the 3-yr Wilkinson Microwave Anisotropy Probe (WMAP) data release is used to identify and analyse such

  4. Distinguishing new physics scenarios at a linear collider with polarized beams

    International Nuclear Information System (INIS)

    Pankov, A.A.; Tsytrinov, A.V.; Paver, N.

    2006-01-01

    Numerous nonstandard dynamics dominated by very high mass exchanges are described at current and future accelerator energies by appropriate contactlike effective interactions among the standard model particles. Correspondingly, they can manifest themselves only through deviations of the cross sections from the standard model predictions. If one such deviation were observed, it would be important to definitely identify, to a given confidence level, the actual source among the various possible nonstandard interactions that, in principle, can explain it. Here we estimate the identification reach on different new physics effective interactions, obtainable from angular distributions of lepton pair production processes at the planned electron-positron International Linear Collider with polarized beams. For each nonstandard model, such an identification reach defines the range in the relevant heavy mass scale parameter where it can be unambiguously distinguished from the other nonstandard models as the source of corrections to the standard model cross sections, in case these are observed. The effective interactions for which we estimate the expected identification reach are the interactions based on gravity in large extra dimensions, in TeV -1 extra dimensions and the compositeness-inspired four-fermion contact interactions. The availability of both beams polarized at the International Linear Collider turns out, in many cases, to dramatically enhance the identification sensitivity

  5. Self-error-rejecting photonic qubit transmission in polarization-spatial modes with linear optical elements

    Science.gov (United States)

    Jiang, YuXiao; Guo, PengLiang; Gao, ChengYan; Wang, HaiBo; Alzahrani, Faris; Hobiny, Aatef; Deng, FuGuo

    2017-12-01

    We present an original self-error-rejecting photonic qubit transmission scheme for both the polarization and spatial states of photon systems transmitted over collective noise channels. In our scheme, we use simple linear-optical elements, including half-wave plates, 50:50 beam splitters, and polarization beam splitters, to convert spatial-polarization modes into different time bins. By using postselection in different time bins, the success probability of obtaining the uncorrupted states approaches 1/4 for single-photon transmission, which is not influenced by the coefficients of noisy channels. Our self-error-rejecting transmission scheme can be generalized to hyperentangled n-photon systems and is useful in practical high-capacity quantum communications with photon systems in two degrees of freedom.

  6. 5G antenna array with wide-angle beam steering and dual linear polarizations

    KAUST Repository

    Klionovski, Kirill

    2017-10-25

    In this paper, we present the design of a switched-beam antenna array at millimeter-wave frequencies for future 5G applications. The proposed antenna array is based on wideband patch antenna elements and a Butler matrix feed network. The patch antenna has a broad radiation pattern for wide-angle beam steering and allows the simultaneous operation with two orthogonal linear polarizations. A combination of two separated Butler matrices provides independent beam steering for both polarizations in the wide operating band. The antenna array has a simple multilayer construction, and it is made on a low-cost Rogers laminate.

  7. 5G antenna array with wide-angle beam steering and dual linear polarizations

    KAUST Repository

    Klionovski, Kirill; Shamim, Atif; Sharawi, Mohammad Said

    2017-01-01

    In this paper, we present the design of a switched-beam antenna array at millimeter-wave frequencies for future 5G applications. The proposed antenna array is based on wideband patch antenna elements and a Butler matrix feed network. The patch antenna has a broad radiation pattern for wide-angle beam steering and allows the simultaneous operation with two orthogonal linear polarizations. A combination of two separated Butler matrices provides independent beam steering for both polarizations in the wide operating band. The antenna array has a simple multilayer construction, and it is made on a low-cost Rogers laminate.

  8. Magnetic field vector and electron density diagnostics from linear polarization measurements in 14 solar prominences

    Science.gov (United States)

    Bommier, V.

    1986-01-01

    The Hanle effect is the modification of the linear polarization parameters of a spectral line due to the effect of the magnetic field. It has been successfully applied to the magnetic field vector diagnostic in solar prominences. The magnetic field vector is determined by comparing the measured polarization to the polarization computed, taking into account all the polarizing and depolarizing processes in line formation and the depolarizing effect of the magnetic field. The method was applied to simultaneous polarization measurements in the Helium D3 line and in the hydrogen beta line in 14 prominences. Four polarization parameters are measured, which lead to the determination of the three coordinates of the magnetic field vector and the electron density, owing to the sensitivity of the hydrogen beta line to the non-negligible effect of depolarizing collisions with electrons and protons of the medium. A mean value of 1.3 x 10 to the 10th power cu. cm. is derived in 14 prominences.

  9. Further comments on the effects of vacuum birefringence on the polarization of X-rays emitted from magnetic neutron stars

    Science.gov (United States)

    Chanan, G. A.; Novick, R.; Silver, E. H.

    1979-01-01

    The birefringence of the vacuum in the presence of strong (of the order of 1 teragauss) magnetic fields will in general affect the polarization of X-rays propagating through these fields. Two of the four Stokes parameters will vary so rapidly with wavelength as to be 'washed out' and unobservable, but the remaining two parameters will be unaffected. These results show that one conclusion of an earlier work is incorrect: Polarized X-ray emission from the surface of a magnetic neutron star will not in general be completely depolarized by the effects of vacuum birefringence. In particular, this birefringence has no effect on the linear polarization of cyclotron emission from the poles of magnetic neutron stars, and a similar result holds for synchrotron emission. More general cases of the propagation of polarized X-rays in magnetic fields are also discussed.

  10. BNL alternating gradient synchrotron with four helical magnets to minimize the losses of the polarized proton beam

    Directory of Open Access Journals (Sweden)

    N. Tsoupas

    2013-04-01

    Full Text Available The principle of using multiple partial helical magnets to preserve the polarization of the proton beam during its acceleration was applied successfully to the alternating gradient synchrotron (AGS which currently operates with two partial helical magnets. In this paper we further explore this idea by using four partial helical magnets placed symmetrically in the AGS ring. This provides many advantages over the present setup of the AGS, which uses two partial helical magnets. First, the symmetric placement of the four helical magnets and their relatively lower field of operation allows for better control of the AGS optics with reduced values of the beta functions especially near beam injection and allows both the vertical and horizontal tunes to be placed within the “spin tune gap,” therefore eliminating the horizontal and vertical intrinsic spin resonances of the AGS during the acceleration cycle. Second, it provides a wider spin tune gap. Third, the vertical spin direction during beam injection and extraction is closer to vertical. Although the spin tune gap, which is created with four partial helices, can also be created with a single or two partial helices, the high field strength of a single helical magnet which is required to generate such a spin tune gap makes the use of the single helical magnet impractical, and that of the two helical magnets rather difficult. In this paper we will provide results on the spin tune and on the optics of the AGS with four partial helical magnets, and compare them with those from the present setup of the AGS that uses two partial helical magnets. Although in this paper we specifically discuss the effect of the four partial helices on the AGS, this method which can eliminate simultaneously the vertical and horizontal intrinsic spin resonances is a general method and can be applied to any medium energy synchrotron which operates in similar energy range like the AGS and provides the required space to

  11. A New Method for Simulating Power Flow Density Focused by a Silicon Lens Antenna Irradiated with Linearly Polarized THz Wave

    Directory of Open Access Journals (Sweden)

    Catur Apriono

    2015-08-01

    Full Text Available A terahertz system uses dielectric lens antennas for focusing and collimating beams of terahertz wave radiation. Linearly polarized terahertz wave radiation has been widely applied in the terahertz system. Therefore, an accurate method for analyzing the power flow density in the dielectric lens antenna irradiated with the linearly polarized terahertz wave radiation is important to design the terahertz systems. In optics, ray-tracing method has been used to calculate the power flow density by a number density of rays. In this study, we propose a method of ray-tracing combined with Fresnel’s transmission, including transmittance and polarization of the terahertz wave radiation to calculate power flow density in a Silicon lens antenna. We compare power flow density calculated by the proposed method with the regular ray-tracing method. When the Silicon lens antenna is irradiated with linearly polarized terahertz wave radiation, the proposed method calculates the power flow density more accurately than the regular ray-tracing.

  12. Polarized radiation in magnetic white dwarfs

    International Nuclear Information System (INIS)

    Rosi, L.A.; Zimmerman, R.L.; Kemp, J.C.

    1976-01-01

    A model for magnetic white dwarfs is proposed which attributes the partially polarized light to synchrotron radiation. The source of the radiation is relativistic electrons trapped in the magnetosphere of a white dwarf. The white dwarf's magnetic field is assumed to be dipolar. The Stokes parameters for the synchrotron radiation are tabulated as a function of frequency, observer's orientation, and energy and spatial distribution of the relativistic electrons. The results of the synchrotron calculations are applied to the polarization observations of Grw+70degree8247 and DQ Herculis. This model can account for the major features of the polarized radiation coming from these two magnetic white dwarfs. The calculations predict for Grw+70degree8247 that the surface magnetic field is B/sub s/approximately-less-than4 x 10 6 gauss, that the incident viewing angle is 45degreeapproximately-less-thantheta 0 approximately-less-than75degree, and that the electrons are trapped with nearly an isotropic distribution about the white dwarf. For DQ Herculis the surface magnetic field is B/sub s/approximately-less-than7 x 10 6 gauss and the trapped electrons are confined to a dislike region about the white dwarf. For both cases the density of electrons in the magnetosphere falls in the range of 10 5 approximately-less-thannapproximately-less-than10 7 cm -3 with energies of about 4--35 MeV

  13. Broadband asymmetric transmission of linearly polarized electromagnetic waves based on chiral metamaterial

    Science.gov (United States)

    Stephen, Lincy; Yogesh, N.; Subramanian, V.

    2018-01-01

    The giant optical activity of chiral metamaterials (CMMs) holds great potential for tailoring the polarization state of an electromagnetic (EM) wave. In controlling the polarization state, the aspect of asymmetric transmission (AT), where a medium allows the EM radiation to pass through in one direction while restricting it in the opposite direction, adds additional degrees of freedom such as one-way channelling functionality. In this work, a CMM formed by a pair of mutually twisted slanted complementary metal strips is realized for broadband AT accompanied with cross-polarization (CP) conversion for linearly polarized EM waves. Numerically, the proposed ultra-thin (˜λ/42) CMM shows broadband AT from 8.58 GHz to 9.73 GHz (bandwidth of 1.15 GHz) accompanied with CP transmission magnitude greater than 0.9. The transmission and reflection spectra reveal the origin of the asymmetric transmission as the direction sensitive cross polarization conversion and anisotropic electric coupling occurring in the structure which is then elaborated with the surface current analysis and electric field distribution within the structure. An experiment is carried out to verify the broadband AT based CP conversion of the proposed CMM at microwave frequencies, and a reliable agreement between numerical and experimental results is obtained. Being ultra-thin, the reported broadband AT based CP conversion of the proposed CMM is useful for controlling radiation patterns in non-reciprocal EM devices and communication networks.

  14. A novel molecular synchrotron for cold collision and EDM experiments.

    Science.gov (United States)

    Hou, Shunyong; Wei, Bin; Deng, Lianzhong; Yin, Jianping

    2016-09-07

    Limited by the construction demands, the state-of-the-art molecular synchrotrons consist of only 40 segments that hardly make a good circle. Imperfections in the circular structure will lead to the appearance of unstable velocity regions (i.e. stopbands), where molecules of certain forward velocity will be lost from the structure. In this paper, we propose a stopband-free molecular synchrotron. It contains 1570 ring electrodes, which nearly make a perfect circle, capable of confining both light and heavy polar molecules in the low-field-seeking states. Molecular packets can be conveniently manipulated with this synchrotron by various means, like acceleration, deceleration or even trapping. Trajectory calculations are carried out using a pulsed (88)SrF molecular beam with a forward velocity of 50 m/s. The results show that the molecular beam can make more than 500 round trips inside the synchrotron with a 1/e lifetime of 6.2 s. The synchrotron can find potential applications in low-energy collision and reaction experiments or in the field of precision measurements, such as the searches for electric dipole moment of elementary particles.

  15. Bhabha vs. Moeller scattering as a contact-interaction analyzer at a polarized linear collider

    International Nuclear Information System (INIS)

    Pankov, A.; Paver, N.

    2002-10-01

    We discuss electron-electron contact-interaction searches in the processes e + e - →e + e - and e - e - →e - e - at planned Linear Colliders run in the e + e - and e - e - modes with both beams longitudinally polarized. Our analysis is based on the measurement, for the two processes, of polarized differential cross sections, and allows to simultaneously take into account the general set of electron contact interaction couplings as independent, non-zero, parameters thus avoiding the simplifying choice of a model. We evaluate the corresponding model-independent constraints on the contact coupling constants, emphasizing the role of the available beam polarization and the complementarity, as far as the chirality of the constants is concerned, of the two processes in giving the best constraints. We also make a comparison with the potential of e + e - →μ μ- at the same energy and initial beams polarization. (author)

  16. Multiwavelength Polarization of Rotation-powered Pulsars

    Energy Technology Data Exchange (ETDEWEB)

    Harding, Alice K.; Kalapotharakos, Constantinos [Astrophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2017-05-10

    Polarization measurements provide strong constraints on models for emission from rotation-powered pulsars. We present multiwavelength polarization predictions showing that measurements over a range of frequencies can be particularly important for constraining the emission location, radiation mechanisms, and system geometry. The results assume a generic model for emission from the outer magnetosphere and current sheet in which optical to hard X-ray emission is produced by synchrotron radiation (SR) from electron–positron pairs and γ -ray emission is produced by curvature radiation (CR) or SR from accelerating primary electrons. The magnetic field structure of a force-free magnetosphere is assumed and the phase-resolved and phase-averaged polarization is calculated in the frame of an inertial observer. We find that large position angle (PA) swings and deep depolarization dips occur during the light-curve peaks in all energy bands. For synchrotron emission, the polarization characteristics are strongly dependent on photon emission radius with larger, nearly 180°, PA swings for emission outside the light cylinder (LC) as the line of sight crosses the current sheet. The phase-averaged polarization degree for SR is less that 10% and around 20% for emission starting inside and outside the LC, respectively, while the polarization degree for CR is much larger, up to 40%–60%. Observing a sharp increase in polarization degree and a change in PA at the transition between X-ray and γ -ray spectral components would indicate that CR is the γ -ray emission mechanism.

  17. Neutron angular distribution in (γ, n reactions with linearly polarized γ-ray beam generated by laser Compton scattering

    Directory of Open Access Journals (Sweden)

    K. Horikawa

    2014-10-01

    Full Text Available In 1957, Agodi predicted that the neutron angular distribution in (γ, n reactions with a 100% linearly polarized γ-ray beam for dipole excitation should be anisotropic and universally described by the simple function of a+b⋅cos⁡(2ϕ at the polar angle θ=90°, where ϕ is the azimuthal angle. However, this prediction has not been experimentally confirmed in over half a century. We have verified experimentally this angular distribution in the (γ, n reaction for 197Au, 127I, and natural Cu targets using linearly polarized laser Compton scattering γ-rays. The result suggests that the (γ→, n reaction is a novel tool to study nuclear physics in the giant dipole resonance region.

  18. The experimental apparatus for synchrotron radiation Moessbauer spectroscopy of BL11 in SPring-8

    International Nuclear Information System (INIS)

    Mitsui, T.; Kitao, S.; Zhang, X.W.; Marushita, M.; Seto, M.

    2001-01-01

    Synchrotron radiation Moessbauer spectroscopy (time spectrum of nuclear forward scattering and nuclear resonant inelastic scattering) enables us to study both the electronic state and lattice dynamics of a target material. Furthermore, the excellent properties of synchrotron radiation (polarization, pulse, small beam size) promise us the unique studies for material science. In order to progress in these studies, some experimental apparatuses were installed in BL11XU of SPring-8

  19. MONO: A program to calculate synchrotron beamline monochromator throughputs

    International Nuclear Information System (INIS)

    Chapman, D.

    1989-01-01

    A set of Fortran programs have been developed to calculate the expected throughput of x-ray monochromators with a filtered synchrotron source and is applicable to bending magnet and wiggler beamlines. These programs calculate the normalized throughput and filtered synchrotron spectrum passed by multiple element, flat un- focussed monochromator crystals of the Bragg or Laue type as a function of incident beam divergence, energy and polarization. The reflected and transmitted beam of each crystal is calculated using the dynamical theory of diffraction. Multiple crystal arrangements in the dispersive and non-dispersive mode are allowed as well as crystal asymmetry and energy or angle offsets. Filters or windows of arbitrary elemental composition may be used to filter the incident synchrotron beam. This program should be useful to predict the intensities available from many beamline configurations as well as assist in the design of new monochromator and analyzer systems. 6 refs., 3 figs

  20. LOW-FREQUENCY OBSERVATIONS OF LINEARLY POLARIZED STRUCTURES IN THE INTERSTELLAR MEDIUM NEAR THE SOUTH GALACTIC POLE

    Energy Technology Data Exchange (ETDEWEB)

    Lenc, E.; Gaensler, B. M.; Sun, X. H.; Sadler, E. M.; Callingham, J. R. [Sydney Institute for Astronomy, School of Physics, The University of Sydney, NSW 2006 (Australia); Willis, A. G. [National Research Council of Canada, Herzberg Astronomy and Astrophysics, P.O. Box 248, Penticton, BC (Canada); Barry, N.; Beardsley, A. P.; Carroll, P. [Department of Physics, University of Washington, Seattle, WA 98195 (United States); Bell, M. E.; Briggs, F. [ARC Centre of Excellence for All-sky Astrophysics (CAASTRO) (Australia); Bernardi, G. [Department of Physics and Electronics, Rhodes University, P.O. Box 94, Grahamstown 6140 (South Africa); Bowman, J. D. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States); Cappallo, R. J.; Corey, B. E. [MIT Haystack Observatory, Westford, MA 01886 (United States); Oliveira-Costa, A. de; Dillon, J. S. [MIT Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Deshpande, A. A.; Dwarkanath, K. S. [Raman Research Institute, Bangalore 560080 (India); Emrich, D. [International Centre for Radio Astronomy Research, Curtin University, Bentley, WA 6102 (Australia); and others

    2016-10-10

    We present deep polarimetric observations at 154 MHz with the Murchison Widefield Array (MWA), covering 625 deg{sup 2} centered on α = 0{sup h}and δ = −27°. The sensitivity available in our deep observations allows an in-band, frequency-dependent analysis of polarized structure for the first time at long wavelengths. Our analysis suggests that the polarized structures are dominated by intrinsic emission but may also have a foreground Faraday screen component. At these wavelengths, the compactness of the MWA baseline distribution provides excellent snapshot sensitivity to large-scale structure. The observations are sensitive to diffuse polarized emission at ∼54′ resolution with a sensitivity of 5.9 mJy beam{sup −1} and compact polarized sources at ∼2.′4 resolution with a sensitivity of 2.3 mJy beam{sup −1} for a subset (400 deg{sup 2}) of this field. The sensitivity allows the effect of ionospheric Faraday rotation to be spatially and temporally measured directly from the diffuse polarized background. Our observations reveal large-scale structures (∼1°–8° in extent) in linear polarization clearly detectable in ∼2 minute snapshots, which would remain undetectable by interferometers with minimum baseline lengths of >110 m at 154 MHz. The brightness temperature of these structures is on average 4 K in polarized intensity, peaking at 11 K. Rotation measure synthesis reveals that the structures have Faraday depths ranging from −2 to 10 rad m{sup −2} with a large fraction peaking at approximately +1 rad m{sup −2}. We estimate a distance of 51 ± 20 pc to the polarized emission based on measurements of the in-field pulsar J2330–2005. We detect four extragalactic linearly polarized point sources within the field in our compact source survey. Based on the known polarized source population at 1.4 GHz and non-detections at 154 MHz, we estimate an upper limit on the depolarization ratio of 0.08 from 1.4 GHz to 154 MHz.

  1. Multiple scattering in synchrotron studies of disordered materials

    International Nuclear Information System (INIS)

    Poulsen, H.F.; Neuefeind, J.

    1995-01-01

    A formalism for the multiple scattering and self-absorption in synchrotron studies of disordered materials is presented. The formalism goes beyond conventionally used approximations and treat the cross sections, the beam characteristics, the state of polarization, and the electronic correction terms in full. Using hard X-rays it is shown how the simulated distributions can be directly compared to experimental data. ((orig.))

  2. Analysis of peripheral thermal damage after laser irradiation of dentin using polarized light microscopy and synchrotron radiation infrared spectromicroscopy

    Science.gov (United States)

    Dela Rosa, Alfredo; Sarma, Anupama V.; Le, Charles Q.; Jones, Robert S.; Fried, Daniel

    2004-05-01

    It is necessary to minimize peripheral thermal damage during laser irradiation, since thermal damage to collagen and mineral compromises the bond strength to restorative materials in dentin and inhibits healing and osteointegration in bone. The overall objective of this study was to test the hypothesis that lasers resonant to the specific absorption of water, collagen, and hydroxyapatite with pulse durations less than the thermal relaxation times at each respective laser wavelength will efficiently remove dentin with minimal peripheral thermal damage. Precise incisions were produced in 3 x 3 mm2 blocks of human dentin using CO2 (9.6 μm), Er:YSGG (2.79 μm), and Nd:YAG (355 nm) lasers with and without a computer controlled water spray. Polarization-sensitive optical coherence tomography was used to obtain optical cross-sections of each incision to determine the rate and efficiency of ablation. The peripheral thermal damage zone around each incision was analyzed using polarized light microscopy (PLM) and Synchrotron-Radiation Fourier Transform Infrared Spectro-microscopy (SR-FTIR). Thermally induced chemical changes to both mineral and the collagen matrix was observed with SR-FTIR with a 10-μm spatial resolution and those changes were correlated with optical changes observed with PLM. Minimal (alveolar bone.

  3. Vectorial structures of linear-polarized Butterfly-Gauss vortex beams in the far zone

    Science.gov (United States)

    Cheng, Ke; Zhou, Yan; Lu, Gang; Yao, Na; Zhong, Xianqiong

    2018-05-01

    By introducing the Butterfly catastrophe to optics, the far-zone vectorial structures of Butterfly-Gauss beam with vortex and non-vortex are studied using the angular spectrum representation and stationary phase method. The influence of topological charge, linear-polarized angle, off-axis distance and scaling length on the far-zone vectorial structures, especially in the Poynting vector and angular momentum density of the corresponding beam is emphasized. The results show that the embedded optical vortex at source plane lead to special dark zones in the far zone, where the number of dark zone equals the absolute value of topological charge of optical vortex. Furthermore, the symmetry and direction of the special dark zones can be controlled by off-axis distance and scaling length, respectively. The linear-polarized angle adjusts only the Poynting vectors of TE and TM terms, but it does not affect those of whole beam. Finally, the vectorial expressions also indicate that the total angular momentum density is certainly zero owing to the far-zone stable structures rather than rotation behaviors.

  4. 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

  5. Bhabha vs. Moeller scattering as a contact-interaction analyzer at a polarized linear collider

    CERN Document Server

    Pankov, A A

    2002-01-01

    We discuss electron-electron contact-interaction searches in the processes e sup + e sup -->e sup + e sup - and e sup - e sup -->e sup - e sup - at planned Linear Colliders run in the e sup + e sup - and e sup - e sup - modes with both beams longitudinally polarized. Our analysis is based on the measurement, for the two processes, of polarized differential cross sections, and allows to simultaneously take into account the general set of electron contact interaction couplings as independent, non-zero, parameters thus avoiding the simplifying choice of a model. We evaluate the corresponding model-independent constraints on the contact coupling constants, emphasizing the role of the available beam polarization and the complementarity, as far as the chirality of the constants is concerned, of the two processes in giving the best constraints. We also make a comparison with the potential of e sup + e sup --> mu supmu sup - at the same energy and initial beams polarization.

  6. ACCURATE POLARIZATION CALIBRATION AT 800 MHz WITH THE GREEN BANK TELESCOPE

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Yu-Wei; Chang, Tzu-Ching; Kuo, Cheng-Yu [Institute of Astronomy and Astrophysics, Academia Sinica, 11F of Astro-Math Building, AS/NTU, 1 Roosevelt Road Sec. 4, Taipei 10617, Taiwan (China); Masui, Kiyoshi Wesley [Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, V6T 1Z1 (Canada); Oppermann, Niels; Pen, Ue-Li [Canadian Institute for Theoretical Astrophysics, University of Toronto, 60 St. George Street, Toronto ON, M5S 3H8 (Canada); Peterson, Jeffrey B., E-mail: ywliao@asiaa.sinica.edu.tw [McWilliams Center for Cosmology, Carnegie Mellon University, Department of Physics, 5000 Forbes Avenue, Pittsburgh PA 15213 (United States)

    2016-12-20

    Polarization leakage of foreground synchrotron emission is a critical issue in H i intensity mapping experiments. While the sought-after H i emission is unpolarized, polarized foregrounds such as Galactic and extragalactic synchrotron radiation, if coupled with instrumental impurity, can mimic or overwhelm the H i signals. In this paper, we present the methodology for polarization calibration at 700–900 MHz, applied on data obtained from the Green Bank Telescope (GBT). We use astrophysical sources, both polarized and unpolarized sources including quasars and pulsars, as calibrators to characterize the polarization leakage and control systematic effects in our GBT H i intensity mapping project. The resulting fractional errors on polarization measurements on boresight are well controlled to within 0.6%–0.8% of their total intensity. The polarized beam patterns are measured by performing spider scans across both polarized quasars and pulsars. A dominant Stokes I to V leakage feature and secondary features of Stokes I to Q and I to U leakages in the 700–900 MHz frequency range are identified. These characterizations are important for separating foreground polarization leakage from the H i 21 cm signal.

  7. ACCURATE POLARIZATION CALIBRATION AT 800 MHz WITH THE GREEN BANK TELESCOPE

    International Nuclear Information System (INIS)

    Liao, Yu-Wei; Chang, Tzu-Ching; Kuo, Cheng-Yu; Masui, Kiyoshi Wesley; Oppermann, Niels; Pen, Ue-Li; Peterson, Jeffrey B.

    2016-01-01

    Polarization leakage of foreground synchrotron emission is a critical issue in H i intensity mapping experiments. While the sought-after H i emission is unpolarized, polarized foregrounds such as Galactic and extragalactic synchrotron radiation, if coupled with instrumental impurity, can mimic or overwhelm the H i signals. In this paper, we present the methodology for polarization calibration at 700–900 MHz, applied on data obtained from the Green Bank Telescope (GBT). We use astrophysical sources, both polarized and unpolarized sources including quasars and pulsars, as calibrators to characterize the polarization leakage and control systematic effects in our GBT H i intensity mapping project. The resulting fractional errors on polarization measurements on boresight are well controlled to within 0.6%–0.8% of their total intensity. The polarized beam patterns are measured by performing spider scans across both polarized quasars and pulsars. A dominant Stokes I to V leakage feature and secondary features of Stokes I to Q and I to U leakages in the 700–900 MHz frequency range are identified. These characterizations are important for separating foreground polarization leakage from the H i 21 cm signal.

  8. Ideas for future synchrotron light sources

    International Nuclear Information System (INIS)

    Jackson, A.; Hassenzahl, W.; Meddahi, M.

    1992-03-01

    Synchrotron light sources have advanced in the past two-to-three decades through three ''generations,'' from irritating parasitic sources on high-energy physics accelerators to dedicated electron and position storage rings of unprecedented low emittance, utilizing undulator and wiggler magnets. The evolution through these three generations followed a predicable, science-driven, course towards brighter beams of VUV- and x-radiation. The requirements of future light sources is not so clear. The limit on how emittance has certainly not been reached, and diffraction-limited sources at shorter wavelengths would be the natural progression from previous generations. However, scientists are now looking at other radiation characteristics that might better serve their needs, for example, more coherent power, fast switching polarization, ultra-short (sub-picosecond) time structure, and synchronized beams for pump-probe experiments. This paper discusses some current ideas that might drive the fourth-generation synchrotron light source

  9. 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.)

  10. Synchrotron radiation resonance Raman spectroscopy (SR3S)

    International Nuclear Information System (INIS)

    Hester, R.E.

    1979-01-01

    The use of normal Raman spectroscopy and resonance Raman spectroscopy to study the structure of molecular species and the nature of their chemical bonds is discussed. The availability of a fully tunable radiation source (the Synchrotron Radiation Source) extending into the ultraviolet raises the possibility of using synchrotron radiation resonance Raman spectroscopy as a sensitive and specific analytical probe. The pulsed nature of the SRS beam may be exploited for time-resolved resonance Raman spectroscopy and its high degree of polarization could be very helpful in the interpretation of spectra. The possibilities are considered under the headings: intensity requirements and comparison with other sources; some applications (e.g. structure of proteins; study of iron-porphyrin unit; study of chlorophylls). (U.K.)

  11. Bistable states of TM polarized non-linear waves guided by symmetric layered structures

    International Nuclear Information System (INIS)

    Mihalache, D.

    1985-04-01

    Dispersion relations for TM polarized non-linear waves propagating in a symmetric single film optical waveguide are derived. The system consists of a layer of thickness d with dielectric constant epsilon 1 bounded at two sides by a non-linear medium characterized by the diagonal dielectric tensor epsilon 11 =epsilon 22 =epsilon 0 , epsilon 33 =epsilon 0 +α|E 3 | 2 , where E 3 is the normal electric field component. For sufficiently large d/lambda (lambda is the wavelength) we predict bistable states of both symmetric and antisymmetric modes provided that the power flow is the control parameter. (author)

  12. Polarized e-bunch acceleration at Cornell RCS: Tentative tracking simulations

    Energy Technology Data Exchange (ETDEWEB)

    Meot, F. [Brookhaven National Lab. (BNL), Upton, NY (United States); Ptitsyn, V. [Brookhaven National Lab. (BNL), Upton, NY (United States); Ranjbar, V. [Brookhaven National Lab. (BNL), Upton, NY (United States); Rubin, D. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2017-10-19

    An option as an injector into eRHIC electron storage ring is a rapid-cyclic synchrotron (RCS). Rapid acceleration of polarized electron bunches has never been done, Cornell synchrotron might lend itself to dedicated tests, which is to be first explored based on numerical investigations. This paper is a very preliminary introduction to the topic.

  13. NONLINEAR REFLECTION PROCESS OF LINEARLY POLARIZED, BROADBAND ALFVÉN WAVES IN THE FAST SOLAR WIND

    Energy Technology Data Exchange (ETDEWEB)

    Shoda, M.; Yokoyama, T., E-mail: shoda@eps.s.u-tokyo.ac.jp [Department of Earth and Planetary Science, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan)

    2016-04-01

    Using one-dimensional numerical simulations, we study the elementary process of Alfvén wave reflection in a uniform medium, including nonlinear effects. In the linear regime, Alfvén wave reflection is triggered only by the inhomogeneity of the medium, whereas in the nonlinear regime, it can occur via nonlinear wave–wave interactions. Such nonlinear reflection (backscattering) is typified by decay instability. In most studies of decay instabilities, the initial condition has been a circularly polarized Alfvén wave. In this study we consider a linearly polarized Alfvén wave, which drives density fluctuations by its magnetic pressure force. For generality, we also assume a broadband wave with a red-noise spectrum. In the data analysis, we decompose the fluctuations into characteristic variables using local eigenvectors, thus revealing the behaviors of the individual modes. Different from the circular-polarization case, we find that the wave steepening produces a new energy channel from the parent Alfvén wave to the backscattered one. Such nonlinear reflection explains the observed increasing energy ratio of the sunward to the anti-sunward Alfvénic fluctuations in the solar wind with distance against the dynamical alignment effect.

  14. Angular distributions as a probe of anomalous ZZH and γZH interactions at a linear collider with polarized beams

    International Nuclear Information System (INIS)

    Rindani, Saurabh D.; Sharma, Pankaj

    2009-01-01

    We examine the contribution of general Z*ZH and γ*ZH three-point interactions arising from new physics to the Higgs production process e + e - →HZ. From Lorentz covariance, each of these vertices may be written in terms of three (complex) form factors, whose real and imaginary parts together make six independent couplings. We take into account possible longitudinal or transverse beam polarization likely to be available at a linear collider. We show how partial cross sections and angular asymmetries in suitable combinations with appropriate beam polarizations can be used to disentangle various couplings from one another. A striking result is that using transverse polarization, one of the γZH couplings, not otherwise accessible, can be determined independently of all other couplings. Transverse polarization also helps in the independent determination of a combination of two other couplings, in contrast to a combination of four accessible with unpolarized or longitudinally polarized beams. We also obtain the sensitivity of the various observables in constraining the new-physics interactions at a linear collider operating at a center-of-mass energy of 500 GeV with longitudinal or transverse polarization.

  15. 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

  16. Personal history of nucleon polarization experiments

    International Nuclear Information System (INIS)

    Chamberlain, O.

    1984-09-01

    The history of nucleon scattering experiments is reviewed, starting with the observation of large proton polarizations in scattering from light elements such as carbon, and ending with the acceleration of polarized proton beams in high-energy synchrotrons. Special mention is made about significant contributions made by C.L. Oxley, L. Wolfenstein, R.D. Tripp, T. Ypsilantis, A. Abragam, M. Borghini, T. Niinikoski, Froissart, Stora, A.D. Krisch, and L.G. Ratner

  17. Research of the impact of coupling between unit cells on performance of linear-to-circular polarization conversion metamaterial with half transmission and half reflection

    Science.gov (United States)

    Guo, Mengchao; Zhou, Kan; Wang, Xiaokun; Zhuang, Haiyan; Tang, Dongming; Zhang, Baoshan; Yang, Yi

    2018-04-01

    In this paper, the impact of coupling between unit cells on the performance of linear-to-circular polarization conversion metamaterial with half transmission and half reflection is analyzed by changing the distance between the unit cells. An equivalent electrical circuit model is then built to explain it based on the analysis. The simulated results show that, when the distance between the unit cells is 23 mm, this metamaterial converts half of the incident linearly-polarized wave into reflected left-hand circularly-polarized wave and converts the other half of it into transmitted left-hand circularly-polarized wave at 4.4 GHz; when the distance is 28 mm, this metamaterial reflects all of the incident linearly-polarized wave at 4.4 GHz; and when the distance is 32 mm, this metamaterial converts half of the incident linearly-polarized wave into reflected right-hand circularly-polarized wave and converts the other half of it into transmitted right-hand circularly-polarized wave at 4.4 GHz. The tunability is realized successfully. The analysis shows that the changes of coupling between unit cells lead to the changes of performance of this metamaterial. The coupling between the unit cells is then considered when building the equivalent electrical circuit model. The built equivalent electrical circuit model can be used to perfectly explain the simulated results, which confirms the validity of it. It can also give help to the design of tunable polarization conversion metamaterials.

  18. History of the polarized beam

    International Nuclear Information System (INIS)

    Parker, E.F.

    1979-01-01

    In 1973, the first high energy polarized proton beam was developed at the Argonne Zero Gradient Synchrotron (ZGS). It operated very successfully and productively until 1979 when the ZGS was shut down permanently. This report describes the development, characteristics, and operations of this facility

  19. Imaging linear and circular polarization features in leaves with complete Mueller matrix polarimetry.

    Science.gov (United States)

    Patty, C H Lucas; Luo, David A; Snik, Frans; Ariese, Freek; Buma, Wybren Jan; Ten Kate, Inge Loes; van Spanning, Rob J M; Sparks, William B; Germer, Thomas A; Garab, Győző; Kudenov, Michael W

    2018-06-01

    Spectropolarimetry of intact plant leaves allows to probe the molecular architecture of vegetation photosynthesis in a non-invasive and non-destructive way and, as such, can offer a wealth of physiological information. In addition to the molecular signals due to the photosynthetic machinery, the cell structure and its arrangement within a leaf can create and modify polarization signals. Using Mueller matrix polarimetry with rotating retarder modulation, we have visualized spatial variations in polarization in transmission around the chlorophyll a absorbance band from 650 nm to 710 nm. We show linear and circular polarization measurements of maple leaves and cultivated maize leaves and discuss the corresponding Mueller matrices and the Mueller matrix decompositions, which show distinct features in diattenuation, polarizance, retardance and depolarization. Importantly, while normal leaf tissue shows a typical split signal with both a negative and a positive peak in the induced fractional circular polarization and circular dichroism, the signals close to the veins only display a negative band. The results are similar to the negative band as reported earlier for single macrodomains. We discuss the possible role of the chloroplast orientation around the veins as a cause of this phenomenon. Systematic artefacts are ruled out as three independent measurements by different instruments gave similar results. These results provide better insight into circular polarization measurements on whole leaves and options for vegetation remote sensing using circular polarization. Copyright © 2018 The Author(s). Published by Elsevier B.V. All rights reserved.

  20. Design of a wire imaging synchrotron radiation detector

    International Nuclear Information System (INIS)

    Kent, J.; Gomez-Cadenas, J.J.; Hogan, A.; King, M.; Rowe, W.; Watson, S.; Von Zanthier, C.; Briggs, D.D.; Levi, M.

    1990-01-01

    This paper documents the design of a detector invented to measure the positions of synchrotron radiation beams for the precision energy spectrometers of the Stanford Linear Collider (SLC). The energy measurements involve the determination, on a pulse-by-pulse basis, of the separation of pairs of intense beams of synchrotron photons in the MeV energy range. The detector intercepts the beams with arrays of fine wires. The ejection of Compton recoil electrons results in charges being developed in the wires, thus enabling a determination of beam positions. 10 refs., 4 figs

  1. Photoemission studies using laboratory and synchrotron sources

    International Nuclear Information System (INIS)

    Phase, D.M.

    2012-01-01

    Synchrotron radiation sources, providing intense, polarized and stable beams of ultra violet soft and hard X-ray photons, are having great impact on physics, chemistry, biology materials science and other areas research. In particular synchrotron radiation has revolutionized photoelectron spectroscopy by enhancing its capabilities for investigating the electronic properties of solids. The first Indian synchrotron storage ring, Indus- 1 is in operation at RRCAT, Indore. The UGC-DAE CSR with the help of university scientist had designed and developed an angle integrated photoelectron spectroscopy (PES) beamline on this 450 MeV storage ring. A storage ring of this kind is most suitable for investigation in the energy range from few electron volts to around five hundred electron volts. In this lecture we will describe the details of PES beamline and its experimental station. Till date the different university users carried out photoemission measurements on variety of samples. Some of the spectra recorded by users will be presented in order to show the capability of this beamline. In the later part we will report a review of our recent research work carried out on dilute magnetic thin films using this beamline. (author)

  2. Room-temperature single-photon sources with definite circular and linear polarizations based on single-emitter fluorescence in liquid crystal hosts

    International Nuclear Information System (INIS)

    Winkler, Justin M; Lukishova, Svetlana G; Bissell, Luke J

    2013-01-01

    Definite circular and linear polarizations of room-temperature single-photon sources, which can serve as polarization bases for quantum key distribution, are produced by doping planar-aligned liquid crystal hosts with single fluorescence emitters. Chiral 1-D photonic bandgap microcavities for a single handedness of circularly polarized light were prepared from both monomeric and oligomeric cholesteric liquid crystals. Fluorescent emitters, such as nanocrystal quantum dots, nitrogen vacancy color centers in nanodiamonds, and rare-earth ions in nanocrystals, were doped into these microcavity structures and used to produce circularly polarized fluorescence of definite handedness. Additionally, we observed circularly polarized resonances in the spectrum of nanocrystal quantum dot fluorescence at the edge of the cholesteric microcavity's photonic stopband. For this polarization we obtained a ∼4.9 enhancement of intensity compared to the polarization of the opposite handedness that propagates without photonic bandgap microcavity effects. Such a resonance is indicative of coupling of quantum dot fluorescence to the cholesteric microcavity mode. We have also used planar-aligned nematic liquid crystal hosts to align DiI dye molecules doped into the host, thereby providing a single-photon source of linear polarization of definite direction. Antibunching is demonstrated for fluorescence of nanocrystal quantum dots, nitrogen vacancy color centers, and dye molecules in these liquid crystal structures.

  3. Use of a synchrotron radiation x-ray microprobe for elemental analysis at the National Synchrotron Light Source

    International Nuclear Information System (INIS)

    Gordon, B.M.

    1980-01-01

    The National Synchrotron Light Source (NSLS) is a facility consisting of a 700 MeV and a 2.5 GeV electron storage ring and dedicated to providing synchrotron radiation in the energy range from the vacuum ultraviolet to high energy x rays. Some of the properties of synchrotron radiation that contribute to its usefulness for x-ray fluorescence are: a continuous, tunable energy spectrum, strong collimation in the horizontal plane, high polarization in the storage ring plane, and relatively low energy deposition. The highest priority is for the development of an x-ray microprobe beam line capable of trace analysis in the parts per million range with spatial resolution as low as one micrometer. An eventual capability for bulk sample analysis is also planned with sensitivities in the more favorable cases beings low as 50 parts per billion in dry biological tissue. The microprobe technique has application to a variety of fields including the geological, medical, materials and environmental sciences. Examples of investigations include multielemental trace analysis across grain boundaries for the study of diffusion and cooling processes in geological and materials sciences samples; in leukocytes and other types of individual cells for studying the relationship between trace element concentrations and disease or nutrition; and in individual particles in air pollution samples

  4. Distinguishing new physics scenarios at a linear collider with polarized beams

    International Nuclear Information System (INIS)

    Pankov, A.A.; Paver, N.; Tsytrinov, A.V.

    2005-12-01

    Numerous non-standard dynamics are described by contact-like effective interactions that can manifest themselves only through deviations of the cross sections from the Standard Model predictions. If one such deviation were observed, it should be important to definitely identify, to a given confidence level, the actual source among the possible non-standard interactions that in principle can explain it. We here estimate the 'identification' reach on different New Physics effective interactions obtainable from angular distributions of lepton pair production processes at the planned International Linear Collider with polarized beams. The models for which we discuss the range in the relevant high mass scales where they can be 'identified' as sources of corrections from the Standard Model predictions, are the interactions based on gravity in large and in TeV -1 extra dimensions and the compositeness-inspired four-fermion contact interactions. The availability of both beams polarized in many cases plays an essential role in enhancing the identification sensitivity. (author)

  5. Theoretical analysis of the background intensity distribution in X-ray Birefringence Imaging using synchrotron bending-magnet radiation

    Science.gov (United States)

    Sutter, John P.; Dolbnya, Igor P.; Collins, Stephen P.; Harris, Kenneth D. M.; Edwards-Gau, Gregory R.; Palmer, Benjamin A.

    2015-04-01

    In the recently developed technique of X-ray Birefringence Imaging, molecular orientational order in anisotropic materials is studied by exploiting the birefringence of linearly polarized X-rays with energy close to an absorption edge of an element in the material. In the experimental setup, a vertically deflecting high-resolution double-crystal monochromator is used upstream from the sample to select the appropriate photon energy, and a horizontally deflecting X-ray polarization analyzer, consisting of a perfect single crystal with a Bragg reflection at Bragg angle of approximately 45°, is placed downstream from the sample to measure the resulting rotation of the X-ray polarization. However, if the experiment is performed on a synchrotron bending-magnet beamline, then the elliptical polarization of the X-rays out of the electron orbit plane affects the shape of the output beam. Also, because the monochromator introduces a correlation between vertical position and photon energy to the X-ray beam, the polarization analyzer does not select the entire beam, but instead selects a diagonal stripe, the slope of which depends on the Bragg angles of the monochromator and the polarization analyzer. In the present work, the final background intensity distribution is calculated analytically because the phase space sampling methods normally used in ray traces are too inefficient for this setup. X-ray Birefringence Imaging data measured at the Diamond Light Source beamline B16 agree well with the theory developed here.

  6. Theoretical analysis of the background intensity distribution in X-ray Birefringence Imaging using synchrotron bending-magnet radiation

    Energy Technology Data Exchange (ETDEWEB)

    Sutter, John P., E-mail: john.sutter@diamond.ac.uk; Dolbnya, Igor P.; Collins, Stephen P. [Diamond Light Source Ltd., Chilton, Didcot, Oxfordshire OX11 0DE (United Kingdom); Harris, Kenneth D. M.; Edwards-Gau, Gregory R. [School of Chemistry, Cardiff University, Park Place, Cardiff CF10 3AT, Wales (United Kingdom); Palmer, Benjamin A. [Department of Structural Biology, Weizmann Institute of Science, 234 Herzl St., Rehovot 7610001 (Israel)

    2015-04-28

    In the recently developed technique of X-ray Birefringence Imaging, molecular orientational order in anisotropic materials is studied by exploiting the birefringence of linearly polarized X-rays with energy close to an absorption edge of an element in the material. In the experimental setup, a vertically deflecting high-resolution double-crystal monochromator is used upstream from the sample to select the appropriate photon energy, and a horizontally deflecting X-ray polarization analyzer, consisting of a perfect single crystal with a Bragg reflection at Bragg angle of approximately 45°, is placed downstream from the sample to measure the resulting rotation of the X-ray polarization. However, if the experiment is performed on a synchrotron bending-magnet beamline, then the elliptical polarization of the X-rays out of the electron orbit plane affects the shape of the output beam. Also, because the monochromator introduces a correlation between vertical position and photon energy to the X-ray beam, the polarization analyzer does not select the entire beam, but instead selects a diagonal stripe, the slope of which depends on the Bragg angles of the monochromator and the polarization analyzer. In the present work, the final background intensity distribution is calculated analytically because the phase space sampling methods normally used in ray traces are too inefficient for this setup. X-ray Birefringence Imaging data measured at the Diamond Light Source beamline B16 agree well with the theory developed here.

  7. Circular polarization control for the European XFEL in the soft X-ray regime

    Energy Technology Data Exchange (ETDEWEB)

    Geloni, Gianluca [European XFEL GmbH, Hamburg (Germany); Kocharyan, Vitali; Saldin, Evgeni [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2011-06-15

    The possibility of producing X-ray radiation with high degree of circular polarization is an important asset at XFEL facilities. Polarization control is most important in the soft X-ray region.However, the baseline of the European XFEL, including the soft X-ray SASE3 line, foresees planar undulators only, yielding linearly-polarized radiation. It is clear that the lowest-risk strategy for implementing polarization control at SASE3 involves adding an APPLE II-type undulator at the end of the planar undulator, in order to exploit the micro bunching from the baseline FEL. Detailed experience is available in synchrotron radiation laboratories concerning the manufacturing of 5 m-long APPLE II undulators. However, the choice of a short helical radiator leads to the problem of background suppression. The driving idea of our proposal is that the background radiation can be suppressed by spatial filtering. This operation can be performed by inserting slits behind the APPLE II radiator, where the linearly-polarized radiation spot size is about 30 times larger than the radiation spot size from the helical radiator. The last 7 cells of the SASE3 undulator are left with an open gap in order to provide a total 42 m drift section for electron beam and radiation. Due to the presence of the drift the linearly-polarized radiation spot size increases, and the linearly polarized background radiation can be suppressed by the slits. At the same time, the microbunch structure is easily preserved, so that intense (100 GW) coherent radiation is emitted in the helical radiator. We propose a filtering setup consisting of a pair of water cooled slits for X-ray beam filtering and of a 5 m-long magnetic chicane, which creates an offset for slit installation immediately behind the helical radiator. Electrons and X-rays are separated before the slits by the magnetic chicane, so that the electron beam can pass by the filtering setup without perturbations. Based on start-to-end simulations we

  8. Circular polarization control for the European XFEL in the soft X-ray regime

    International Nuclear Information System (INIS)

    Geloni, Gianluca; Kocharyan, Vitali; Saldin, Evgeni

    2011-06-01

    The possibility of producing X-ray radiation with high degree of circular polarization is an important asset at XFEL facilities. Polarization control is most important in the soft X-ray region.However, the baseline of the European XFEL, including the soft X-ray SASE3 line, foresees planar undulators only, yielding linearly-polarized radiation. It is clear that the lowest-risk strategy for implementing polarization control at SASE3 involves adding an APPLE II-type undulator at the end of the planar undulator, in order to exploit the micro bunching from the baseline FEL. Detailed experience is available in synchrotron radiation laboratories concerning the manufacturing of 5 m-long APPLE II undulators. However, the choice of a short helical radiator leads to the problem of background suppression. The driving idea of our proposal is that the background radiation can be suppressed by spatial filtering. This operation can be performed by inserting slits behind the APPLE II radiator, where the linearly-polarized radiation spot size is about 30 times larger than the radiation spot size from the helical radiator. The last 7 cells of the SASE3 undulator are left with an open gap in order to provide a total 42 m drift section for electron beam and radiation. Due to the presence of the drift the linearly-polarized radiation spot size increases, and the linearly polarized background radiation can be suppressed by the slits. At the same time, the microbunch structure is easily preserved, so that intense (100 GW) coherent radiation is emitted in the helical radiator. We propose a filtering setup consisting of a pair of water cooled slits for X-ray beam filtering and of a 5 m-long magnetic chicane, which creates an offset for slit installation immediately behind the helical radiator. Electrons and X-rays are separated before the slits by the magnetic chicane, so that the electron beam can pass by the filtering setup without perturbations. Based on start-to-end simulations we

  9. Synchrotron radiation gives insight in smaller and smaller crystals

    International Nuclear Information System (INIS)

    Hintsches, E.

    1983-01-01

    Scientists from the ''Max-Planck-Institut fuer Festkoerperforschung'' in Stuttgart have extended the method of X-ray analysis to study the structure of very small crystals. For the first time a crystal with 6 μm linear dimension has been successfully analysed using the synchrotron radiation from the DESY electron synchrotron at Hamburg. Thus this important method of analysis has been demonstrated to be usefull for structural studies of crystals, which are smaller by a factor of 20 than hitherto. (orig.) [de

  10. BROOKHAVEN: Spin rotator to boost polarization

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    The Alternating Gradient Synchrotron (AGS) at Brookhaven holds the world record energy for spin polarized proton beams at 22 GeV. However this required a complicated two-week commissioning effort to overcome 39 imperfection depolarizing resonances and six intrinsic depolarizing resonances

  11. Analytical fits to the synchrotron functions

    Science.gov (United States)

    Fouka, Mourad; Ouichaoui, Saad

    2013-06-01

    Accurate fitting formulae to the synchrotron function, F(x), and its complementary function, G(x), are performed and presented. The corresponding relative errors are less than 0.26% and 0.035% for F(x) and G(x), respectively. To this end we have, first, fitted the modified Bessel functions, K5/3(x) and K2/3(x). For all the fitted functions, the general fit expression is the same, and is based on the well known asymptotic forms for low and large values of x for each function. It consists of multiplying each asymptotic form by a function that tends to unity or zero for low and large values of x. Simple formulae are suggested in this paper, depending on adjustable parameters. The latter have been determined by adopting the Levenberg-Marquardt algorithm. The proposed formulae should be of great utility and simplicity for computing spectral powers and the degree of polarization for synchrotron radiation, both for laboratory and astrophysical applications.

  12. Applications of photon-in, photon-out spectroscopy with third-generation, synchrotron-radiation sources

    International Nuclear Information System (INIS)

    Lindle, D.W.; Perera, R.C.C.

    1991-01-01

    This report discusses the following topics: Mother nature's finest test probe; soft x-ray emission spectroscopy with high-brightness synchrotron radiation sources; anisotropy and polarization of x-ray emission from atoms and molecules; valence-hole fluorescence from molecular photoions as a probe of shape-resonance ionization: progress and prospects; structural biophysics on third-generation synchrotron sources; ultra-soft x-ray fluorescence-yield XAFS: an in situ photon-in, photon-out spectroscopy; and x-ray microprobe: an analytical tool for imaging elemental composition and microstructure

  13. Scanning differential polarization microscope: Its use to image linear and circular differential scattering

    International Nuclear Information System (INIS)

    Mickols, W.; Maestre, M.F.

    1988-01-01

    A differential polarization microscope that couples the sensitivity of single-beam measurement of circular dichroism and circular differential scattering with the simultaneous measurement of linear dichroism and linear differential scattering has been developed. The microscope uses a scanning microscope stage and single-point illumination to give the very shallow depth of field found in confocal microscopy. This microscope can operate in the confocal mode as well as in the near confocal condition that can allow one to program the coherence and spatial resolution of the microscope. This microscope has been used to study the change in the structure of chromatin during the development of sperm in Drosophila

  14. Analysis of signal to background ratio in synchrotron radiation X-ray fluorescence

    International Nuclear Information System (INIS)

    Sakurai, Kenji; Gohshi, Yohichi; Iida, Atsuo.

    1988-01-01

    The signal to background (S/B) ratio in energy dispersive X-ray fluorescence using synchrotron radiation (SR) was quantitatively analyzed. The S/B ratio, which has been significantly improved by taking advantage of the polarized nature of SR, was found to be strongly dependent on geometrical factors of the measurement system. From the analysis on the origin of the scattered background, the dependence of the S/B ratio on the geometry was quantitatively explained, mainly by the polarization properties of SR. Experimental conditions could be optimized by adjusting the degree of polarization of the incident beam and the detector solid angle. (author)

  15. 112 Gbit/s single-polarization silicon coherent receiver with hybrid-integrated BiCMOS linear TIA

    NARCIS (Netherlands)

    Verbist, J.; Zhang, J.; Moeneclaey, B.; van Weerdenburg, J.; van Uden, R.; Okonkwo, C.; Yin, X.; Bauwelinck, J.; Roelkens, G.

    2015-01-01

    We report the design, fabrication and verification of a single-polarization silicon coherent receiver with a low-power linear TIA array. Error-free operation assuming FEC is shown at bitrates of 112 Gbit/s (28 Gbaud 16-QAM) and 56 Gbit/s (28 Gbaud QPSK).

  16. Linear Polarimetry with γ→e+e− Conversions

    Directory of Open Access Journals (Sweden)

    Denis Bernard

    2017-11-01

    Full Text Available γ -rays are emitted by cosmic sources by non-thermal processes that yield either non-polarized photons, such as those from π 0 decay in hadronic interactions, or linearly polarized photons from synchrotron radiation and the inverse-Compton up-shifting of these on high-energy charged particles. Polarimetry in the MeV energy range would provide a powerful tool to discriminate among “leptonic” and “hadronic” emission models of blazars, for example, but no polarimeter sensitive above 1 MeV has ever been flown into space. Low-Z converter telescopes such as silicon detectors are developed to improve the angular resolution and the point-like sensitivity below 100 MeV. We have shown that in the case of a homogeneous, low-density active target such as a gas time-projection chamber (TPC, the single-track angular resolution is even better and is so good that in addition the linear polarimetry of the incoming radiation can be performed. We actually characterized the performance of a prototype of such a telescope on beam. Track momentum measurement in the tracker would enable calorimeter-free, large effective area telescopes on low-mass space missions. An optimal unbiased momentum estimate can be obtained in the tracker alone based on the momentum dependence of multiple scattering, from a Bayesian analysis of the innovations of Kalman filters applied to the tracks.

  17. Ultra-wideband high-efficiency reflective linear-to-circular polarization converter based on metasurface at terahertz frequencies.

    Science.gov (United States)

    Jiang, Yannan; Wang, Lei; Wang, Jiao; Akwuruoha, Charles Nwakanma; Cao, Weiping

    2017-10-30

    The polarization conversion of electromagnetic (EM) waves, especially linear-to-circular (LTC) polarization conversion, is of great significance in practical applications. In this study, we propose an ultra-wideband high-efficiency reflective LTC polarization converter based on a metasurface in the terahertz regime. It consists of periodic unit cells, each cell of which is formed by a double split resonant square ring, dielectric layer, and fully reflective gold mirror. In the frequency range of 0.60 - 1.41 THz, the magnitudes of the reflection coefficients reach approximately 0.7, and the phase difference between the two orthogonal electric field components of the reflected wave is close to 90° or -270°. The results indicate that the relative bandwidth reaches 80% and the efficiency is greater than 88%, thus, ultra-wideband high-efficiency LTC polarization conversion has been realized. Finally, the physical mechanism of the polarization conversion is revealed. This converter has potential applications in antenna design, EM measurement, and stealth technology.

  18. Vacuum-ultraviolet circular dichroism spectrophotometer using synchrotron radiation

    International Nuclear Information System (INIS)

    Matsu, K.; Yonehara, R.; Gekko, K.

    2004-01-01

    Full text: Circular dichroism (CD) spectroscopy is powerful for analyzing the structure of optically active materials such as biopolymers. However, no commercial CD spectrophotometer is capable of measuring the CD in the vacuum ultraviolet (VUV) region below 190 nm because of technical difficulties involved in the light source, optical device, and sample cell. CD measurements extended to the VUV region can provide more detailed and new information on the structure of biopolymers based on the higher energy transition of chromophores such as hydroxyl and acetal groups. We have constructed a VUVCD spectrophotometer to measure the CD spectra of biomaterials in aqueous solutions in the 310-140 nm wavelength region under a high vacuum, using a small-scale SR source (0.7 GeV) at Hiroshima Synchrotron Radiation Center (HiSOR). All optical devices of the spectrophotometer were set up under a high vacuum (10 -6 Torr), to avoid the absorption of light by air and water vapor. The SR light is separated into two orthogonal linearly polarized light beams by a linear polarizer and then modulated to circularly polarized light at 50 kHz by a photo-elastic modulator (PEM). In order to control PEM accurately and to stabilize the lock-in amplifier under a high vacuum, we used the optical servo-control system. Also, an assembled-type MgF 2 cell with a temperature-control unit was constructed using a Peltier thermoelectric element. Its path length can be adjusted by various Tefron spacers in the range from 1.3 to 50 μm and its temperature can be controlled within an accuracy of ± 1 deg C in the range from -30 to 70 deg C. The performance of the spectrophotometer and MgF 2 cell constructed was tested by monitoring the CD spectra of ammonium d-camphor-10-sulfonate (ACS), D- and L-isomers of amino acids. These obtained results demonstrate that the optical system and the sample cell constructed normally operate under a high vacuum to provide useful information on the structure analysis of

  19. 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

  20. Spatial anisotropy of neutrons emitted from the 56Fe(γ ,n )55Fe reaction with a linearly polarized γ -ray beam

    Science.gov (United States)

    Hayakawa, T.; Shizuma, T.; Miyamoto, S.; Amano, S.; Takemoto, A.; Yamaguchi, M.; Horikawa, K.; Akimune, H.; Chiba, S.; Ogata, K.; Fujiwara, M.

    2016-04-01

    We have measured the azimuthal anisotropy of neutrons emitted from the 56Fe(γ ,n )55Fe reaction with a linearly polarized γ -ray beam generated by laser Compton scattering at NewSUBARU. Neutron yields at the polar angle of 90∘ have been measured as a function of the azimuthal angle ϕ between the detector and the linear polarization plane of the γ -ray beam. The azimuthal anisotropy of neutrons measured at ϕ =0∘ , 10∘, 25∘, 45∘, 60∘, 70∘, and 90∘ has been well reproduced using a theoretically predicted function of a +b cos(2 ϕ ) .

  1. Impact of polarized e- and e+ beams at a future Linear Collider and a Z-factory Part II - Physics beyond the Standard Model

    International Nuclear Information System (INIS)

    Moortgat-Pick, G

    2011-01-01

    Polarization of both beams at a future Linear Collider would be ideal for facing both expected and unforeseen challenges in searches for new physics: fixing the chirality of the couplings and enabling the higher precision for the polarization measurement itself as well as for polarization-dependent observables, it provides a powerful tool for studying new physics at the future Linear Collider, such as discovering new particles, analyzing signals model-independently and resolving precisely the underlying model. Techniques and engineering designs for a polarized-positron source are well advanced. Potential constraints concerning luminosity, commissioning and operating issues appear to be under control. This article mainly treats with the impact of polarized beams on physics beyond the Standard Model, whereas the fundamentals in polarization as well as the gain in electroweak precision physics are summarized in the corresponding part I.

  2. Present status and future project on hadron physics with KEK proton synchrotron

    International Nuclear Information System (INIS)

    Masaike, Akira

    1984-01-01

    Recent experimental results on hadron physics using a 12 GeV proton synchrotron at KEK are presented. Several future projects which have been proposed as a post-shutdown program from 1985 including hypernuclear physics, physics with polarized beam and heavy ion beam are also reported. (author)

  3. A precision synchrotron radiation detector using phosphorescent screens

    International Nuclear Information System (INIS)

    Jung, C.K.; Lateur, M.; Nash, J.; Tinsman, J.; Butler, J.; Wormser, G.

    1990-01-01

    A precision detector to measure synchrotron radiation beam positions has been designed and installed as part of beam energy spectrometers at the Stanford Linear Collider (SLC). The distance between pairs of synchrotron radiation beams is measured absolutely to better than 28 μm on a pulse-to-pulse basis. This contributes less than 5 MeV to the error in the measurement of SLC beam energies (approximately 50 GeV). A system of high-resolution video cameras viewing precisely aligned fiducial wire arrays overlaying phosphorescent screens has achieved this accuracy. 3 refs., 5 figs., 1 tab

  4. PROPERTIES OF INTERSTELLAR TURBULENCE FROM GRADIENTS OF LINEAR POLARIZATION MAPS

    International Nuclear Information System (INIS)

    Burkhart, Blakesley; Lazarian, A.; Gaensler, B. M.

    2012-01-01

    Faraday rotation of linearly polarized radio signals provides a very sensitive probe of fluctuations in the interstellar magnetic field and ionized gas density resulting from magnetohydrodynamic (MHD) turbulence. We used a set of statistical tools to analyze images of the spatial gradient of linearly polarized radio emission (|∇P|) for both observational data from a test image of the Southern Galactic Plane Survey (SGPS) and isothermal three-dimensional simulations of MHD turbulence. Visually, in both observations and simulations, a complex network of filamentary structures is seen. Our analysis shows that the filaments in |∇P| can be produced both by interacting shocks and random fluctuations characterizing the non-differentiable field of MHD turbulence. The latter dominates for subsonic turbulence, while the former is only present in supersonic turbulence. We show that supersonic and subsonic turbulence exhibit different distributions as well as different morphologies in the maps of |∇P|. Particularly, filaments produced by shocks show a characteristic 'double jump' profile at the sites of shock fronts resulting from delta function-like increases in the density and/or magnetic field, while those produced by subsonic turbulence show a single jump profile. In order to quantitatively characterize these differences, we use the topology tool known as the genus curve as well as the probability distribution function moments of the image distribution. We find that higher values for the moments correspond to cases of |∇P| with larger sonic Mach numbers. The genus analysis of the supersonic simulations of |∇P| reveals a 'swiss cheese' topology, while the subsonic cases have characteristics of a 'clump' topology. Based on the analysis of the genus and the higher order moments, the SGPS test region data have a distribution and morphology that match subsonic- to transonic-type turbulence, which confirms what is now expected for the warm ionized medium.

  5. PROPERTIES OF INTERSTELLAR TURBULENCE FROM GRADIENTS OF LINEAR POLARIZATION MAPS

    Energy Technology Data Exchange (ETDEWEB)

    Burkhart, Blakesley; Lazarian, A. [Astronomy Department, University of Wisconsin, Madison, 475 N. Charter St., WI 53711 (United States); Gaensler, B. M. [Sydney Institute for Astronomy, School of Physics, University of Sydney, NSW 2006 (Australia)

    2012-04-20

    Faraday rotation of linearly polarized radio signals provides a very sensitive probe of fluctuations in the interstellar magnetic field and ionized gas density resulting from magnetohydrodynamic (MHD) turbulence. We used a set of statistical tools to analyze images of the spatial gradient of linearly polarized radio emission (|{nabla}P|) for both observational data from a test image of the Southern Galactic Plane Survey (SGPS) and isothermal three-dimensional simulations of MHD turbulence. Visually, in both observations and simulations, a complex network of filamentary structures is seen. Our analysis shows that the filaments in |{nabla}P| can be produced both by interacting shocks and random fluctuations characterizing the non-differentiable field of MHD turbulence. The latter dominates for subsonic turbulence, while the former is only present in supersonic turbulence. We show that supersonic and subsonic turbulence exhibit different distributions as well as different morphologies in the maps of |{nabla}P|. Particularly, filaments produced by shocks show a characteristic 'double jump' profile at the sites of shock fronts resulting from delta function-like increases in the density and/or magnetic field, while those produced by subsonic turbulence show a single jump profile. In order to quantitatively characterize these differences, we use the topology tool known as the genus curve as well as the probability distribution function moments of the image distribution. We find that higher values for the moments correspond to cases of |{nabla}P| with larger sonic Mach numbers. The genus analysis of the supersonic simulations of |{nabla}P| reveals a 'swiss cheese' topology, while the subsonic cases have characteristics of a 'clump' topology. Based on the analysis of the genus and the higher order moments, the SGPS test region data have a distribution and morphology that match subsonic- to transonic-type turbulence, which confirms what is now

  6. Synchrotron radiation microprobe quantitative analysis method for biomedical specimens

    International Nuclear Information System (INIS)

    Xu Qing; Shao Hanru

    1994-01-01

    Relative changes of trace elemental content in biomedical specimens are obtained easily by means of synchrotron radiation X-ray fluorescence microprobe analysis (SXRFM). However, the accurate assignment of concentration on a g/g basis is difficult. Because it is necessary to know both the trace elemental content and the specimen mass in the irradiated volume simultaneously. the specimen mass is a function of the spatial position and can not be weighed. It is possible to measure the specimen mass indirectly by measuring the intensity of Compton scattered peak for normal XRF analysis using a X-ray tube with Mo anode, if the matrix was consisted of light elements and the specimen was a thin sample. The Compton peak is not presented in fluorescence spectrum for white light SXRFM analysis. The continuous background in the spectrum was resulted from the Compton scattering with a linear polarization X-ray source. Biomedical specimens for SXRFM analysis, for example biological section and human hair, are always a thin sample for high energy X-ray, and they consist of H,C,N and O etc. light elements, which implies a linear relationship between the specimen mass and the Compton scattering background in the high energy region of spectrum. By this way , it is possible to carry out measurement of concentration for SXRFM analysis

  7. Linearly polarized photoluminescence of anisotropically strained c-plane GaN layers on stripe-shaped cavity-engineered sapphire substrate

    Science.gov (United States)

    Kim, Jongmyeong; Moon, Daeyoung; Lee, Seungmin; Lee, Donghyun; Yang, Duyoung; Jang, Jeonghwan; Park, Yongjo; Yoon, Euijoon

    2018-05-01

    Anisotropic in-plane strain and resultant linearly polarized photoluminescence (PL) of c-plane GaN layers were realized by using a stripe-shaped cavity-engineered sapphire substrate (SCES). High resolution X-ray reciprocal space mapping measurements revealed that the GaN layers on the SCES were under significant anisotropic in-plane strain of -0.0140% and -0.1351% along the directions perpendicular and parallel to the stripe pattern, respectively. The anisotropic in-plane strain in the GaN layers was attributed to the anisotropic strain relaxation due to the anisotropic arrangement of cavity-incorporated membranes. Linearly polarized PL behavior such as the observed angle-dependent shift in PL peak position and intensity comparable with the calculated value based on k.p perturbation theory. It was found that the polarized PL behavior was attributed to the modification of valence band structures induced by anisotropic in-plane strain in the GaN layers on the SCES.

  8. The national synchrotron light source and its applications

    Energy Technology Data Exchange (ETDEWEB)

    Williams, G.P.

    1989-01-01

    We describe the National Synchrotron Light Source facility including its beamlines and operational characteristics. Research results on selected beamlines on the VUV ring which highlight new experimental capabilities are described since they are more relevant to the program at HESYRL. Examples chosen are spin-polarized photoemission, infra-red surface science, high resolution core level spectroscopy, X- Ray lithography, photoelectron/Auger coincidence spectroscopy and high electron momentum resolution surface studies. 7 refs., 3 figs., 3 tabs.

  9. Optical synchrotron emission in the southern lobe of 3C33

    Energy Technology Data Exchange (ETDEWEB)

    Meisenheimer, K; Roeser, H -J

    1986-02-06

    Charge coupled device polarimetry at a wavelength of 660 nm has detected a highly-polarized optical source, which is coincident with the radio hotspot at the leading edge of the southern lobe of 3C33. The optical polarization data perfectly match the high-frequency Very Large Array observations, thus providing the first direct evidence for optical synchrotron radiation from a classic double radio source. The extended structure of the emission region requires a huge particle accelerator boosting electrons to highly relativistic energies (up to 100 GeV) over a region several kiloparsecs in extent.

  10. Electromagnetic frozen waves with radial, azimuthal, linear, circular, and elliptical polarizations

    Science.gov (United States)

    Corato-Zanarella, Mateus; Zamboni-Rached, Michel

    2016-11-01

    Frozen waves (FWs) are a class of diffraction- and attenuation-resistant beams whose intensity pattern along the direction of propagation can be chosen arbitrarily, thus making them relevant for engineering the spatial configuration of optical fields. To date, analyses of such beams have been done essentially for the scalar case, with the vectorial nature of the electromagnetic fields often neglected. Although it is expected that the field components keep the fundamental properties of the scalar FWs, a deeper understanding of their electromagnetic counterparts is mandatory in order to exploit their different possible polarization states. The purpose of this paper is to study the properties of electromagnetic FWs with radial, azimuthal, linear, circular, and elliptical polarizations under paraxial and nonparaxial regimes in nonabsorbing media. An intensity pattern is chosen for a scalar FW, and the vectorial solutions are built after it via the use of Maxwell's equations. The results show that the field components and the longitudinal component of the time-averaged Poynting vector closely follow the pattern chosen even under highly nonparaxial conditions, showing the robustness of the FW structure to parameters variations.

  11. Polarized Uniform Linear Array System: Beam Radiation Pattern, Beamforming Diversity Order, and Channel Capacity

    Directory of Open Access Journals (Sweden)

    Xin Su

    2015-01-01

    Full Text Available There have been many studies regarding antenna polarization; however, there have been few publications on the analysis of the channel capacity for polarized antenna systems using the beamforming technique. According to Chung et al., the channel capacity is determined by the density of scatterers and the transmission power, which is obtained based on the assumption that scatterers are uniformly distributed on a 3D spherical scattering model. However, it contradicts the practical scenario, where scatterers may not be uniformly distributed under outdoor environment, and lacks the consideration of fading channel gain. In this study, we derive the channel capacity of polarized uniform linear array (PULA systems using the beamforming technique in a practical scattering environment. The results show that, for PULA systems, the channel capacity, which is boosted by beamforming diversity, can be determined using the channel gain, beam radiation pattern, and beamforming diversity order (BDO, where the BDO is dependent on the antenna characteristics and array configurations.

  12. Unique heavy lepton signature at e{sup +}e{sup -} linear collider with polarized beams

    Energy Technology Data Exchange (ETDEWEB)

    Moortgat-Pick, G. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Osland, P. [Univ. Bergen (Norway). Dept. of Physics and Technology; Pankov, A.A.; Tsytrinov, A.V. [Technical Univ. Gomel (Belarus). Abdus Salam ICTP Affliated Centre

    2013-03-15

    We explore the effects of neutrino and electron mixing with exotic heavy leptons in the process e{sup +}e{sup -}{yields}W{sup +}W{sup -} within E{sub 6} models. We examine the possibility of uniquely distinguishing and identifying such effects of heavy neutral lepton exchange from Z-Z' mixing within the same class of models and also from analogous ones due to competitor models with anomalous trilinear gauge couplings (AGC) that can lead to very similar experimental signatures at the e{sup +}e{sup -} International Linear Collider (ILC) for {radical}(s)=350, 500 GeV and 1 TeV. Such clear identification of the model is possible by using a certain double polarization asymmetry. The availability of both beams being polarized plays a crucial role in identifying such exotic-lepton admixture. In addition, the sensitivity of the ILC for probing exotic-lepton admixture is substantially enhanced when the polarization of the produced W{sup {+-}} bosons is considered.

  13. Linear versus circular polarization of head coils - comparison on phantom and in the clinic

    International Nuclear Information System (INIS)

    Schratter, M.; Kramer, J.; Prayer, L.; Wimberger, D.; Imhof, H.; Schmid, W.

    1990-01-01

    Two different head coils - one with linear polarization and the other with circular polarization - were compared under the same measurement conditions. Comparison was done on a phantom with waterfilled and gadolinium-filled pin-holes, as well as on anatomical MR images of 23 volunteers. In three volunteers the whole brain was examined while, in the remaining 20 volunteers the sella region or cerebellopontine angleregion was examined. Criteria for comparison were signal-to-noise ratio, background noise, and detail resolution (phantom), as well as subjective criteria - image sharpness, anatomical, contrast, and recognition of anatomical details -, evaluated on anatomical MR images by four radiologists independently of each other. The results show a significant improvement of signal-to-noise ratio, lower background noise and therefore marked improvement of images harpness, and moderate improvement in the recognition of anatomical details using the circular polarized head coil; as for as detail resolution and anatomical contrast were concerned, however, no significant difference was seen between the two coils. Major advantages of the circular, polarized head coil in clinical application are shorter measurement times (reduced number of acquisitions), as well as thinner slices without loss of signal-to-noise ratio. (orig.) [de

  14. Synchrotron light

    International Nuclear Information System (INIS)

    2001-01-01

    'Synchrotron Light' is an interactive and detailed introduction to the physics and technology of the generation of coherent radiation from accelerators as well as to its widespread high-tech applications in science, medicine and engineering. The topics covered are the interaction of light and matter, the technology of synchrotron light sources, spectroscopy, imaging, scattering and diffraction of X-rays, and applications to materials science, biology, biochemistry, medicine, chemistry, food and pharmaceutical technology. All synchrotron light facilities are introduced with their home-page addresses. 'Synchrotron Light' provides an instructive and comprehensive multimedia learning tool for students, experienced practitioners and novices wishing to apply synchrotron radiation in their future work. Its multiple-entry points permit an easy exploration of the CD-Rom according to the users knowledge and interest. 2-D and 3-D animations and virtual reconstruction with computer-generated images guide visitors into the scientific and technical world of a synchrotron and into the applications of synchrotron radiation. This bilingual (English and French) CD-Rom can be used for self-teaching and in courses at various levels in physics, chemistry, engineering, and biology. (author)

  15. 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).

  16. The Weizsäcker-Williams distribution of linearly polarized gluons (and its fluctuations) at small x

    Energy Technology Data Exchange (ETDEWEB)

    Dumitru, Adrian; Skokov, Vladimir

    2017-09-11

    The conventional and linearly polarized Weizsäcker-Williams gluon distributions at small x are defined from the two-point function of the gluon field in light-cone gauge. They appear in the cross section for dijet production in deep inelastic scattering at high energy. We determine these functions in the small-x limit from solutions of the JIMWLK evolution equations and show that they exhibit approximate geometric scaling. Also, we discuss the functional distributions of these WW gluon distributions over the JIMWLK ensemble at rapidity Y ~ 1/αs. These are determined by a 2d Liouville action for the logarithm of the covariant gauge function g2tr A+(q)A+(-q). For transverse momenta on the order of the saturation scale we observe large variations across configurations (evolution trajectories) of the linearly polarized distribution up to several times its average, and even to negative values.

  17. Non-perturbative calculation of equilibrium polarization of stored electron beams

    International Nuclear Information System (INIS)

    Yokoya, Kaoru.

    1992-05-01

    Stored electron/positron beams polarize spontaneously owing to the spin-flip synchrotron radiation. In the existing computer codes, the degree of the equilibrium polarization has been calculated using perturbation expansions in terms of the orbital oscillation amplitudes. In this paper a new numerical method is presented which does not employ the perturbation expansion. (author)

  18. Synchrotron-radiation research

    International Nuclear Information System (INIS)

    Cunningham, J.E.

    1982-01-01

    The use of radiation from synchrotron sources has started a renaissance in materials, physics, chemistry, and biology. Synchrotron radiation has advantages over conventional x rays in that its source brightness is a thousand times greater throughout a continuous energy spectrum, and resonances are produced with specific electron energy levels. Two major synchrotron radiation sources are operated by DOE: the Stanford Synchrotron Radiation Laboratory at SLAC, and the National Synchrotron Light Source at Brookhaven

  19. Status and future plans of polarized beams at COSY

    Science.gov (United States)

    Lorentz, B.; Gebel, R.; Lehrach, A.; Maier, R.; Prasuhn, D.; Stockhorst, H.

    2011-05-01

    In this paper we report on the present status and future plans of polarized beams in the COSY synchrotron ring. COSY is a synchrotron ring in the momentum range from 295 to 3700 MeV/c. Polarized deuterons and protons are routinely delivered to experiments over the whole momentum range. No depolarization occurs during the acceleration of deuterons in COSY. For polarized protons many depolarizing resonances are crossed without polarization loss. At imperfection resonances, vertical steerer magnets are used to increase the resonance strength, leading to a complete polarization reversal. At intrinsic resonances a fast tune jump quadrupole is used to quickly cross the resonances without loss of polarization. Typical proton polarizations are close to 0.8 below 2.1 GeV/c and about 0.6 for higher momenta. During recent operation an induced depolarizing resonance was used for accurate determination of the relative momentum spread dp/p of the stored beam yielding an accuracy of better than 10-4. For spin filter studies of the PAX collaboration a low beta target section was installed in 2009 and was successfully put into operation early 2010. An upgrade of the EDDA polarimeter electronics and data acquisition system is underway to ensure continued availability of the polarimeter, which is essential for the polarized proton operation of COSY. In the near future it is planned to install a Siberian snake solenoid of 4.5 Tm to be able to provide in addition to vertically polarized protons, longitudinal polarization as well. This solenoid will allow the preparation of a longitudinally polarized beam up to a kinetic energy of 500 MeV.

  20. Improved linearity in AlGaN/GaN metal-insulator-semiconductor high electron mobility transistors with nonlinear polarization dielectric

    International Nuclear Information System (INIS)

    Gao, Tao; Xu, Ruimin; Kong, Yuechan; Zhou, Jianjun; Kong, Cen; Dong, Xun; Chen, Tangsheng

    2015-01-01

    We demonstrate highly improved linearity in a nonlinear ferroelectric of Pb(Zr 0.52 Ti 0.48 )-gated AlGaN/GaN metal-insulator-semiconductor high electron mobility transistor (MIS-HEMT). Distinct double-hump feature in the transconductance-gate voltage (g m -V g ) curve is observed, yielding remarkable enhancement in gate voltage swing as compared to MIS-HEMT with conventional linear gate dielectric. By incorporating the ferroelectric polarization into a self-consistent calculation, it is disclosed that in addition to the common hump corresponding to the onset of electron accumulation, the second hump at high current level is originated from the nonlinear polar nature of ferroelectric, which enhances the gate capacitance by increasing equivalent dielectric constant nonlinearly. This work paves a way for design of high linearity GaN MIS-HEMT by exploiting the nonlinear properties of dielectric

  1. Spin analysis of photoelectrons by using synchrotron radiation

    International Nuclear Information System (INIS)

    Yagishita, Akira

    1983-03-01

    This report is the proceedings of a workshop on ''Spin analysis of photoelectrons by using synchrotron radiation'' held at National Laboratory for High Energy Physics on October 21, 1982. The purpose of this workshop was to examine the feasibility of the experiment on the spin analysis of photoelectrons at the photon factory which has started the operation in 1982. The workshop covered the following subjects on the spin analysis of photoelectrons and on the detectors for spin polarization; the experiment and the theory on the spin analysis of photoelectrons emitted from gas and solid, the detectors for measuring the spin polarization of electron beam, the test experiment on a Mott detector, and further problems. The proceedings contain five papers related to the above subjects. (Asami, T.)

  2. Dependence of effective spectrum width of synchrotron radiation on particle energy

    Energy Technology Data Exchange (ETDEWEB)

    Bagrov, V.G. [Tomsk State University, Department of Physics, Tomsk (Russian Federation); Institute of High Current Electronics, Tomsk (Russian Federation); University of Sao Paulo, Institute of Physics, Sao Paulo (Brazil); Gitman, D.M. [Tomsk State University, Department of Physics, Tomsk (Russian Federation); University of Sao Paulo, Institute of Physics, Sao Paulo (Brazil); P.N. Lebedev Physical Institute, Moscow (Russian Federation); Levin, A.D. [University of Sao Paulo, Institute of Physics, Sao Paulo (Brazil); Loginov, A.S.; Saprykin, A.D. [Tomsk State University, Department of Physics, Tomsk (Russian Federation)

    2017-05-15

    In the classical theory of synchrotron radiation, for the exact quantitative characterization of spectral properties, the concept of effective spectral width is introduced. In the first part of our work, published in EJPC 75 (2015), the effective spectral width as a function of the energy E of the radiating particle was obtained only in the ultra-relativistic approximation. In this article, which can be considered as a natural continuation of this work, a complete investigation is presented of the dependence of the effective width of the synchrotron radiation spectrum on energy for any values of E and for all the polarization components of the radiation. Numerical calculations were carried out for an effective width not exceeding 100 harmonics. (orig.)

  3. Development of Low Level RF Control Systems for Superconducting Heavy Ion Linear Accelerators, Electron Synchrotrons and Storage Rings

    CERN Document Server

    Aminov, Bachtior; Kolesov, Sergej; Pekeler, Michael; Piel, Christian; Piel, Helmut

    2005-01-01

    Since 2001 ACCEL Instruments is supplying low level RF control systems together with turn key cavity systems. The early LLRF systems used the well established technology based on discrete analogue amplitude and phase detectors and modulators. Today analogue LLRF systems can make use of advanced vector demodulators and modulators combined with a fast computer controlled analogue feed back loop. Feed forward control is implemented to operate the RF cavity in an open loop mode or to compensate for predictable perturbations. The paper will introduce the general design philosophy and show how it can be adapted to different tasks as controlling a synchrotron booster nc RF system at 500 MHz, or superconducting storage ring RF cavities, as well as a linear accelerator at 176 MHz formed by a chain of individually driven and controlled superconducting λ/2 cavities.

  4. Analysis of the collagen birefringence and the relative attenuation coefficient of health and burned skin irradiated with linearly polarized He-Ne laser

    International Nuclear Information System (INIS)

    Silva, Daniela de Fatima Teixeira da

    2002-01-01

    Low-intensity laser therapy is characterized by its ability to induce athermic effects and nondestructive photobiological processes. Although it has been in use for more than 40 years, this phototherapy is still not an established therapeutic modality. The objectives of this study were: to quantify the collagen fibers organization by polarized light microscopy in normal and burned skin samples at day 17 post-injury considering preferential axis as the animal's spinal column and aligning the linear laser polarization in two directions of polarization, parallel or perpendicular to this axis; to determine the relative attenuation coefficient for the intensity light by the technique of imaging the light distribution in normal and burned skin during wound healing process taking only parallel direction of polarization. To reach the objectives, burns about 6 mm in diameter were created with liquid N 2 on the back of the rats and the lesions were irradiated on days 3, 7, 10 and 14 post-wounding, D= 1 J/cm 2 , to investigate the effects of low-intensity linearly polarized He-Ne laser beam on skin wounds healing. Control lesions were not irradiated. The results have demonstrated that: the skin samples irradiated with linearly parallel polarized He-Ne laser beam showed collagen fibers more organized; burned skin samples presents a higher attenuation coefficient than normal skin samples. These results are important to optimize low intensity laser therapy dosimetry on acceleration wound healing. (author)

  5. Intense Vibronic Modulation of the Chiral Photoelectron Angular Distribution Generated by Photoionization of Limonene Enantiomers with Circularly Polarized Synchrotron Radiation.

    Science.gov (United States)

    Rafiee Fanood, Mohammad M; Ganjitabar, Hassan; Garcia, Gustavo A; Nahon, Laurent; Turchini, Stefano; Powis, Ivan

    2018-04-17

    Photoionization of the chiral monoterpene limonene has been investigated using polarized synchrotron radiation between the adiabatic ionization threshold, 8.505 and 23.5 eV. A rich vibrational structure is seen in the threshold photoelectron spectrum and is interpreted using a variety of computational methods. The corresponding photoelectron circular dichroism-measured in the photoelectron angular distribution as a forward-backward asymmetry with respect to the photon direction-was found to be strongly dependent on the vibronic structure appearing in the photoelectron spectra, with the observed asymmetry even switching direction in between the major vibrational peaks. This effect can be ultimately attributed to the sensitivity of this dichroism to small phase shifts between adjacent partial waves of the outgoing photoelectron. These observations have implications for potential applications of this chiroptical technique, where the enantioselective analysis of monoterpene components is of particular interest. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. A Design Of Feeding Network For A Dual-Linear Polarization, Stacked, Probe-Fed Microstrip Patch Antenna Array

    DEFF Research Database (Denmark)

    Jaworski, G.; Krozer, Viktor

    2004-01-01

    Components of multilayer feed network are presented for application in broad-band dual-linear polarized stacked C-band antenna. Measurement results of wide band matching circuits and different types of power divider networks constituting parts of BFN demonstrate wideband operation. Suitable...

  7. 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.

  8. Improved linearity in AlGaN/GaN metal-insulator-semiconductor high electron mobility transistors with nonlinear polarization dielectric

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Tao [Fundamental Science on EHF Laboratory, University of Electronic Science and Technology of China (UESTC), Chengdu 611731 (China); Science and Technology on Monolithic Integrated Circuits and Modules Laboratory, Nanjing Electronic Devices Institute, Nanjing 210016 (China); Xu, Ruimin [Fundamental Science on EHF Laboratory, University of Electronic Science and Technology of China (UESTC), Chengdu 611731 (China); Kong, Yuechan, E-mail: kycfly@163.com; Zhou, Jianjun; Kong, Cen; Dong, Xun; Chen, Tangsheng [Science and Technology on Monolithic Integrated Circuits and Modules Laboratory, Nanjing Electronic Devices Institute, Nanjing 210016 (China)

    2015-06-15

    We demonstrate highly improved linearity in a nonlinear ferroelectric of Pb(Zr{sub 0.52}Ti{sub 0.48})-gated AlGaN/GaN metal-insulator-semiconductor high electron mobility transistor (MIS-HEMT). Distinct double-hump feature in the transconductance-gate voltage (g{sub m}-V{sub g}) curve is observed, yielding remarkable enhancement in gate voltage swing as compared to MIS-HEMT with conventional linear gate dielectric. By incorporating the ferroelectric polarization into a self-consistent calculation, it is disclosed that in addition to the common hump corresponding to the onset of electron accumulation, the second hump at high current level is originated from the nonlinear polar nature of ferroelectric, which enhances the gate capacitance by increasing equivalent dielectric constant nonlinearly. This work paves a way for design of high linearity GaN MIS-HEMT by exploiting the nonlinear properties of dielectric.

  9. Polarization variablity among Wolf-Rayet stars. IV. A complete lack of circular polarization in the optical continuum

    International Nuclear Information System (INIS)

    Robert, C.; Moffat, A.F.J.

    1989-01-01

    Quasi-simultaneous blue and red, broadband optical monitoring in linear and circular polarization and in intensity has been carried out over an interval of three weeks for several Wolf-Rayet stars that show relatively large Delta P variations in linear polarization. No significant varying Delta V component of circular polarization is detected in any of these stars. The lower upper limit Delta V/Delta P implies that the intrinsic linearly polarized light which does vary cannot be produced by electrons gyrating in a magnetic field, unless they are ultrarelativistic - a rather unlikely situation. The low mean circular polarization typically observed is probably interstellar in origin. Lack of periodicity in the observed variations of linear polarization implies that even weak magnetic field loops are unlikely to be involved in confining pockets of wind plasma. The observed linear polarization variations are related mainly to electron scattering. 25 refs

  10. Ortho-Babinet polarization-interrogating filter: an interferometric approach to polarization measurement.

    Science.gov (United States)

    Van Delden, Jay S

    2003-07-15

    A novel, interferometric, polarization-interrogating filter assembly and method for the simultaneous measurement of all four Stokes parameters across a partially polarized irradiance image in a no-moving-parts, instantaneous, highly sensitive manner is described. In the reported embodiment of the filter, two spatially varying linear retarders and a linear polarizer comprise an ortho-Babinet, polarization-interrogating (OBPI) filter. The OBPI filter uniquely encodes the incident ensemble of electromagnetic wave fronts comprising a partially polarized irradiance image in a controlled, deterministic, spatially varying manner to map the complete state of polarization across the image to local variations in a superposed interference pattern. Experimental interferograms are reported along with a numerical simulation of the method.

  11. Magnetic X-Ray Scattering with Synchrotron Radiation

    DEFF Research Database (Denmark)

    Moncton, D. E.; Gibbs, D.; Bohr, Jakob

    1986-01-01

    With the availability of high-brilliance synchrotron radiation from multiple wigglers, magnetic X-ray scattering has become a powerful new probe of magnetic structure and phase transitions. Similar to the well-established magnetic neutron scattering technique, magnetic X-ray scattering methods have...... many complementary advantages. A brief review is presented of the history of magnetic X-ray scattering as well as recent results obtained in studies of the rare-earth magnet holmium with emphasis on instrumentational aspects. In particular, the development of a simple polarization analyzer...... to distinguish charge and magnetic scattering is described....

  12. The ratio R = dσL/dσT in heavy-quark pair leptoproduction as a probe of linearly polarized gluons in unpolarized proton

    Science.gov (United States)

    Efremov, A. V.; Ivanov, N. Ya.; Teryaev, O. V.

    2018-05-01

    We study the Callan-Gross ratio R = dσL / dσT in heavy-quark pair leptoproduction, lN →l‧ Q Q bar X, as a probe of linearly polarized gluons inside unpolarized proton, where dσT (dσL) is the differential cross section of the γ* N → Q Q bar X process initiated by a transverse (longitudinal) virtual photon. Note first that the maximal value for the quantity R allowed by the photon-gluon fusion with unpolarized gluons is large, about 2. We calculate the contribution of the transverse-momentum dependent gluonic counterpart of the Boer-Mulders function, h1 ⊥g , describing the linear polarization of gluons inside unpolarized proton. Our analysis shows that the maximum value of the ratio R depends strongly on the gluon polarization; it varies from 0 to Q2/4m2 depending on h1⊥g . We conclude that the Callan-Gross ratio in heavy-quark pair leptoproduction is predicted to be large and very sensitive to the contribution of linearly polarized gluons. For this reason, future measurements of the longitudinal and transverse components of the charm and bottom production cross sections at the proposed EIC and LHeC colliders seem to be very promising for determination of the linear polarization of gluons inside unpolarized proton.

  13. HIGH-RESOLUTION LINEAR POLARIMETRIC IMAGING FOR THE EVENT HORIZON TELESCOPE

    Energy Technology Data Exchange (ETDEWEB)

    Chael, Andrew A.; Johnson, Michael D.; Narayan, Ramesh; Doeleman, Sheperd S. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Wardle, John F. C. [Brandeis University, Physics Department, Waltham, MA 02454 (United States); Bouman, Katherine L., E-mail: achael@cfa.harvard.edu [Massachusetts Institute of Technology, Computer Science and Artificial Intelligence Laboratory, 32 Vassar Street, Cambridge, MA 02139 (United States)

    2016-09-20

    Images of the linear polarizations of synchrotron radiation around active galactic nuclei (AGNs) highlight their projected magnetic field lines and provide key data for understanding the physics of accretion and outflow from supermassive black holes. The highest-resolution polarimetric images of AGNs are produced with Very Long Baseline Interferometry (VLBI). Because VLBI incompletely samples the Fourier transform of the source image, any image reconstruction that fills in unmeasured spatial frequencies will not be unique and reconstruction algorithms are required. In this paper, we explore some extensions of the Maximum Entropy Method (MEM) to linear polarimetric VLBI imaging. In contrast to previous work, our polarimetric MEM algorithm combines a Stokes I imager that only uses bispectrum measurements that are immune to atmospheric phase corruption, with a joint Stokes Q and U imager that operates on robust polarimetric ratios. We demonstrate the effectiveness of our technique on 7 and 3 mm wavelength quasar observations from the VLBA and simulated 1.3 mm Event Horizon Telescope observations of Sgr A* and M87. Consistent with past studies, we find that polarimetric MEM can produce superior resolution compared to the standard CLEAN algorithm, when imaging smooth and compact source distributions. As an imaging framework, MEM is highly adaptable, allowing a range of constraints on polarization structure. Polarimetric MEM is thus an attractive choice for image reconstruction with the EHT.

  14. Performance study of monochromatic synchrotron X-ray computed tomography using a linear array detector

    Energy Technology Data Exchange (ETDEWEB)

    Kazama, Masahiro; Takeda, Tohoru; Itai, Yuji [Tsukuba Univ., Ibaraki (Japan). Inst. of Clinical Medicine; Akiba, Masahiro; Yuasa, Tetsuya; Hyodo, Kazuyuki; Ando, Masami; Akatsuka, Takao

    1997-09-01

    Monochromatic x-ray computed tomography (CT) using synchrotron radiation (SR) is being developed for detection of non-radioactive contrast materials at low concentration for application in clinical diagnosis. A new SR-CT system with improved contrast resolution, was constructed using a linear array detector which provides wide dynamic ranges and a double monochromator. The performance of this system was evaluated in a phantom and a rat model of brain ischemia. This system consists of a silicon (111) double crystal monochromator, an x-ray shutter, an ionization chamber, x-ray slits, a scanning table for the target organ, and an x-ray linear array detector. The research was carried out at the BLNE-5A bending magnet beam line of the Tristan Accumulation Ring in KEK, Japan. In this experiment, the reconstructed image of the spatial-resolution phantom clearly showed the 1 mm holes. At 1 mm slice thickness, the above K-edge image of the phantom showed contrast resolution at the concentration of 200 {mu}g/ml iodine-based contrast materials whereas the K-edge energy subtraction image showed contrast resolution at the concentration of 500 {mu}g/ml contrast materials. The cerebral arteries filled with iodine microspheres were clearly revealed, and the ischemic regions at the right temporal lobe and frontal lobe were depicted as non-vascular regions. The measured minimal detectable concentration of iodine on the above K-edge image is about 6 times higher than the expected value of 35.3 {mu}g/ml because of the high dark current of this detector. Thus, the use of a CCD detector which is cooled by liquid nitrogen to improve the dynamic range of the detector, is being under construction. (author)

  15. Intense γ-ray generation for a polarized positron beam in a linear collider

    Directory of Open Access Journals (Sweden)

    Y. Miyahara

    2001-12-01

    Full Text Available γ-ray generation by Compton backscattering in an optical lens series with periodic focal points is considered to produce a polarized positron beam for a linear collider. The lens series is composed of 20 unit cells with a length of 210 mm. Each lens has a hole to pass an electron beam with an energy of 5.8 GeV and the generated γ rays. It is shown by diffraction analysis that laser beam loss in the series is very small, and the beam size is periodically reduced to 26 μm. Electron beam size is reduced to 34 μm in a superconducting solenoid with a field of 15 T. To get a required γ-ray yield of 7×10^{15} γ/s, only one circularly polarized CO_{2} laser source with a power of 24 kW is needed.

  16. Development of polarized beam conversion system for the linear collider complex

    International Nuclear Information System (INIS)

    Viilleval'd, G.S.; Vsevolozhskaya, T.A.; Karasyuk, V.N.; Sil'vestrov, G.I.; Chernyakin, A.D.

    1983-01-01

    Results of development of the polarized beam conversion system for the 150 GeV linear collider aiming at the linear collider operation with a high repetition rate (approximately 10 Hz), are presented. It is shown, that the conversion can be realized by means of ondulator radiation. Structurally, the spiral ondulator is two identical solenoids, inserted in each other in such a way, that their winding turns are alternating in the direction along the axis and they are supplied by countercurrents. The main parameters of the ondulator are as follows : winding pitch -0.7 cm, the ondulator length 150 m. For generation a field of the intensity 5 kOe it has been suggested that solenoids should be supplied by sinusoidal pulse current of duration approximately 200 μs. It is shown, that the introduction of iron into solenoid increases the efficiency by a factor of 2.1 and 2.7 in the ondulator with iron only in interloop gaps and with the addition of iron locking magnetic counterflow

  17. Mapping of trace elements with photon microprobes: x-ray fluorescence with focussed synchrotron radiation

    International Nuclear Information System (INIS)

    Hanson, A.L.; Jones, K.W.; Gordon, B.M.; Pounds, J.G.; Rivers, M.L.; Schidlovsky, G.

    1985-04-01

    High energy electron synchrotron storage rings provide copious quantities of polarized photons that make possible the mapping of many trace elements with sensitivities at the parts per billion (ppB) level with spatial resolutions in the micrometer range. The brightness of the x-ray ring of the National Synchrotron Light Source (NSLS), presently being commissioned, will be five orders of magnitude larger than that of the bremsstrahlung spectrum of state-of-the-art rotating anode tubes. We will discuss mapping trace elements with a photon microprobe presently being constructed for use at the NSLS. This microprobe will have micrometer spatial resolution

  18. Synchrotron radiation and its various uses in physics, chemistry and biology

    Energy Technology Data Exchange (ETDEWEB)

    Farge, Y [Laboratoire pour l' Utilisation du Rayonnement Electromagnetique (LURE), Paris-11 Univ., 91 - Orsay (France)

    1975-01-01

    The synchrotron radiation emitted by synchrotrons or storage rings has exceptional properties: spectral continuity from X-rays to radiofrequencies, high intensity, focussed emission in the orbit plane, polarization, and time pulsed structure. The radiation is a unique tool for spectroscopic investigations in the far uv or X-rays on atoms, molecules, or solids. Time resolved spectroscopy in the nano and subnanosecond range is now available in a very broad wavelength range. In the X-ray range, these sources are revolutionary because they are more powerful than the best X-ray tubes by two to four orders of magnitude; it will be very soon possible to do kinetic measurements with typical times of one second and less either by diffraction, scattering, or topography.

  19. Focusing of white synchrotron radiation using large-acceptance cylindrical refractive lenses made of single – crystal diamond

    Energy Technology Data Exchange (ETDEWEB)

    Polikarpov, M., E-mail: polikarpov.maxim@mail.ru [Immanuel Kant Baltic Federal University, Nevskogo 14a, 23600 Kaliningrad (Russian Federation); Snigireva, I. [European Synchrotron Radiation Facility, 71 avenue des Martyrs, Grenoble 38043 (France); Snigirev, A. [Immanuel Kant Baltic Federal University, Nevskogo 14a, 23600 Kaliningrad (Russian Federation); European Synchrotron Radiation Facility, 71 avenue des Martyrs, Grenoble 38043 (France)

    2016-07-27

    Large-aperture cylindrical refractive lenses were manufactured by laser cutting of single-crystal diamond. Five linear single lenses with apertures of 1 mm and the depth of the structure of 1.2 mm were fabricated and tested at the ESRF ID06 beamline performing the focusing of white-beam synchrotron radiation. Uniform linear focus was stable during hours of exposure, representing such lenses as pre-focusing and collimating devices suitable for the front-end sections of today synchrotron radiation sources.

  20. Focusing of white synchrotron radiation using large-acceptance cylindrical refractive lenses made of single – crystal diamond

    International Nuclear Information System (INIS)

    Polikarpov, M.; Snigireva, I.; Snigirev, A.

    2016-01-01

    Large-aperture cylindrical refractive lenses were manufactured by laser cutting of single-crystal diamond. Five linear single lenses with apertures of 1 mm and the depth of the structure of 1.2 mm were fabricated and tested at the ESRF ID06 beamline performing the focusing of white-beam synchrotron radiation. Uniform linear focus was stable during hours of exposure, representing such lenses as pre-focusing and collimating devices suitable for the front-end sections of today synchrotron radiation sources.

  1. The RHIC polarized H{sup −} ion source

    Energy Technology Data Exchange (ETDEWEB)

    Zelenski, A., E-mail: zelenski@bnl.gov; Atoian, G.; Raparia, D.; Ritter, J.; Steski, D. [Brookhaven National Laboratory, Upton, New York 11973 (United States)

    2016-02-15

    A novel polarization technique had been successfully implemented for the Relativistic Heavy Ion Collider (RHIC) polarized H{sup −} ion source upgrade to higher intensity and polarization. In this technique, a proton beam inside the high magnetic field solenoid is produced by ionization of the atomic hydrogen beam (from external source) in the He-gaseous ionizer cell. Further proton polarization is produced in the process of polarized electron capture from the optically pumped Rb vapor. The use of high-brightness primary beam and large cross sections of charge-exchange cross sections resulted in production of high intensity H{sup −} ion beam of 85% polarization. The source very reliably delivered polarized beam in the RHIC Run-2013 and Run-2015. High beam current, brightness, and polarization resulted in 75% polarization at 23 GeV out of Alternating Gradient Synchrotron (AGS) and 60%-65% beam polarization at 100-250 GeV colliding beams in RHIC.

  2. Synchrotron light beam and a synchrotron light experiment facility

    International Nuclear Information System (INIS)

    Ando, Masami

    1980-01-01

    In the National Laboratory for High Energy Physics, about two years ago, the requirements of synchrotron light beam in respective measuring instruments were discussed. Then, also the arrangement (lattice) of a storage ring, the nature of synchrotron light beam, a synchrotron light experiment facility and the arrangement of the beam lines were studied. During the period of two years since then, due to the changes in the circumstances, the design of the lattice was altered. Accordingly, the arrangement of the beam lines and of measuring instruments were largely changed. At this point, the results of discussions in various meetings are described, though they may still be subject to future changes, with due consideration to beam, environment and beam lines required for the design of the measuring instruments: (1) storage ring and synchrotron light beam, (2) requirements on small beam size and beam stability, (3) a synchrotron light experiment facility. (J.P.N.)

  3. Magnetic field effects on ultrafast lattice compression dynamics of Si(111) crystal when excited by linearly-polarized femtosecond laser pulses

    Science.gov (United States)

    Hatanaka, Koji; Odaka, Hideho; Ono, Kimitoshi; Fukumura, Hiroshi

    2007-03-01

    Time-resolved X-ray diffraction measurements of Si (111) single crystal are performed when excited by linearly-polarized femtosecond laser pulses (780 nm, 260 fs, negatively-chirped, 1 kHz) under a magnetic field (0.47 T). Laser fluence on the sample surface is 40 mJ/cm^2, which is enough lower than the ablation threshold at 200 mJ/cm^2. Probing X-ray pulses of iron characteristic X-ray lines at 0.193604 and 0.193998 nm are generated by focusing femtosecond laser pulses onto audio-cassette tapes in air. Linearly-polarized femtosecond laser pulse irradiation onto Si(111) crystal surface induces transient lattice compression in the picosecond time range, which is confirmed by transient angle shift of X-ray diffraction to higher angles. Little difference of compression dynamics is observed when the laser polarization is changed from p to s-pol. without a magnetic field. On the other hand, under a magnetic field, the lattice compression dynamics changes when the laser is p-polarized which is vertical to the magnetic field vector. These results may be assigned to photo-carrier formation and energy-band distortion.

  4. Photoemission spectroscopy using synchrotron radiation

    International Nuclear Information System (INIS)

    Kobayashi, K.L.I.

    1980-01-01

    It is an epoch making event for photoemission spectroscopy that the light sources of continuous wavelength from vacuum ultra-violet to X-ray region have become available by the advent of synchrotron radiation. Specifically the progress after stable intense light has become obtainable from storage rings is very significant. One of the features of these synchrotron radiation is its extreme polarization of radiating pattern. Though the elementary processes of photoemission out of solids are the basic themes, phenomenalistic 3-stage model is usually applied to the analysis of experiments. In this model, the process of photoemission is considered by dividing into three stages, namely the generation of photoelectrons due to optical transition between electron status -- the transportation of photoelectrons to solid surfaces -- breaking away from the surfaces. The spectrometers, the energy analyzers of photoelectrons, and sample-preparing room used for photoemission spectroscopy are described. Next, energy distribution curves are explained. At the end, photoelectron yield spectroscopy, CFS (constant final energy spectroscopy) and CIS (constant initial energy spectroscopy), Auger yield and interatomic Auger yield, the determination of surface structure by normal emission CIS, and surface EXAFS (extended X-ray absorption fine structure) are described. As seen above, the application specifically to surface physics is promising in the future. (Wakatsuki, Y.)

  5. Evaluation of radiative spin polarization in an electron storage ring

    Energy Technology Data Exchange (ETDEWEB)

    Chao, A W [Stanford Linear Accelerator Center, CA (USA)

    1981-02-15

    We have developed a matrix formalism that provides an accurate way of evaluating the degree of spin polarization built up through the process of synchrotron radiation under a wide variety of storage ring operation conditions.

  6. Synchrotron radiation in Australia

    International Nuclear Information System (INIS)

    Garrett, R.F.

    2002-01-01

    Full text: Synchrotron radiation research in Australia is entering a new era with the commencement of the Australian synchrotron project, which will construct a 3 GeV third generation synchrotron facility at Monash University in Victoria. To date Australian scientists have used overseas facilities, primarily those managed by the Australian Synchrotron Research Program in Japan and the USA. A fast developing and maturing Australian synchrotron user program has developed around these overseas facilities. The field of synchrotron radiation and its importance to a wide range of research will be introduced and Australia's current involvement and facilities will be described. The current status and technical specifications of the Australian synchrotron will be presented. Copyright (2002) Australian X-ray Analytical Association Inc

  7. 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

  8. 200 MeV RF linac for synchrotron injection

    International Nuclear Information System (INIS)

    Whitham, K.; Anamkath, H.; Lyons, S.; Manca, J.; Miller, R.; Treas, P.; Zante, T.; Miller, R.

    1992-01-01

    Construction has been completed on an electron linear accelerator for the Brookhaven National Laboratory. This accelerator will be used for the injection of a 200 MeV electron beam into a synchrotron for lithography experiments. This paper describes the conceptual design of the linac, its e-gun pulser, and its control and timing systems. 3 figs., ref

  9. Longitudinal tracking studies for a high intensity proton synchrotron

    International Nuclear Information System (INIS)

    Lessner, E.; Cho, Y.; Harkay, K.; Symon, K.

    1995-01-01

    Results from longitudinal tracking studies for a high intensity proton synchrotron designed for a 1-MW spallation source are presented. The machine delivers a proton beam of 0.5 mA time-averaged current at a repetition rate of 30 Hz. The accelerator is designed to have radiation levels that allow hands-on-maintenance. However, the high beam intensity causes strong space charge fields whose effects may lead to particle loss and longitudinal instabilities. The space charge fields modify the particle distribution, distort the stable bucket area and reduce the rf linear restoring force. Tracking simulations were conducted to analyze the space charge effects on the dynamics of the injection and acceleration processes and means to circumvent them. The tracking studies led to the establishment of the injected beam parameters and rf voltage program that minimized beam loss and longitudinal instabilities. Similar studies for a 10-GeV synchrotron that uses the 2-GeV synchrotron as its injector are also discussed

  10. Modeling radio circular polarization in the Crab nebula

    Science.gov (United States)

    Bucciantini, N.; Olmi, B.

    2018-03-01

    In this paper, we present, for the first time, simulated maps of the circularly polarized synchrotron emission from the Crab nebula, using multidimensional state of the art models for the magnetic field geometry. Synchrotron emission is the signature of non-thermal emitting particles, typical of many high-energy astrophysical sources, both Galactic and extragalactic ones. Its spectral and polarization properties allow us to infer key information on the particles distribution function and magnetic field geometry. In recent years, our understanding of pulsar wind nebulae has improved substantially thanks to a combination of observations and numerical models. A robust detection or non-detection of circular polarization will enable us to discriminate between an electron-proton plasma and a pair plasma, clarifying once for all the origin of the radio emitting particles, setting strong constraints on the pair production in pulsar magnetosphere, and the role of turbulence in the nebula. Previous attempts at measuring the circular polarization have only provided upper limits, but the lack of accurate estimates, based on reliable models, makes their interpretation ambiguous. We show here that those results are above the expected values, and that current polarimetric techniques are not robust enough for conclusive result, suggesting that improvements in construction and calibration of next generation radio facilities are necessary to achieve the desired sensitivity.

  11. Dazzling new light source opens at Stanford synchrotron radiation laboratory

    CERN Multimedia

    2004-01-01

    SPEAR3, the Stanford Positron Electron Asymmetric Ring, was formally opened at a dedication ceremony at the Stanford Linear Accelerator Center on Jan. 29. It incorporates the latest technology to make it competitive with the best synchrotron sources in the world (1/2 page)

  12. High resolution synchrotron light analysis at ELSA

    Energy Technology Data Exchange (ETDEWEB)

    Switka, Michael; Zander, Sven; Hillert, Wolfgang [Bonn Univ. (Germany). Elektronen-Stretcher Anlage ELSA-Facility (ELSA)

    2013-07-01

    The pulse stretcher ring ELSA provides polarized electrons with energies up to 3.5 GeV for external hadron experiments. In order to suffice the need of stored beam intensities towards 200 mA, advanced beam instability studies need to be carried out. An external diagnostic beamline for synchrotron light analysis has been set up and provides the space for multiple diagnostic tools including a streak camera with time resolution of <1 ps. Beam profile measurements are expected to identify instabilities and reveal their thresholds. The effect of adequate countermeasures is subject to analysis. The current status of the beamline development is presented.

  13. Parsec-scale Faraday rotation and polarization of 20 active galactic nuclei jets

    Science.gov (United States)

    Kravchenko, E. V.; Kovalev, Y. Y.; Sokolovsky, K. V.

    2017-05-01

    We perform polarimetry analysis of 20 active galactic nuclei jets using the very long baseline array at 1.4, 1.6, 2.2, 2.4, 4.6, 5.0, 8.1, 8.4 and 15.4 GHz. The study allowed us to investigate linearly polarized properties of the jets at parsec scales: distribution of the Faraday rotation measure (RM) and fractional polarization along the jets, Faraday effects and structure of Faraday-corrected polarization images. Wavelength dependence of the fractional polarization and polarization angle is consistent with external Faraday rotation, while some sources show internal rotation. The RM changes along the jets, systematically increasing its value towards synchrotron self-absorbed cores at shorter wavelengths. The highest core RM reaches 16 900 rad m-2 in the source rest frame for the quasar 0952+179, suggesting the presence of highly magnetized, dense media in these regions. The typical RM of transparent jet regions has values of an order of a hundred rad m-2. Significant transverse RM gradients are observed in seven sources. The magnetic field in the Faraday screen has no preferred orientation, and is observed to be random or regular from source to source. Half of the sources show evidence for the helical magnetic fields in their rotating magneto-ionic media. At the same time jets themselves contain large-scale, ordered magnetic fields and tend to align its direction with the jet flow. The observed variety of polarized signatures can be explained by a model of spine-sheath jet structure.

  14. Synchrotron Physics and Industry: new opportunities for technology transfer

    International Nuclear Information System (INIS)

    Williams, P.

    2002-01-01

    Full text: In 1979, with the opening in the UK of the world's first dedicated synchrotron light source, the SRS, experimental science in virtually every discipline underwent what amounted to a major revolution. The unique nature of synchrotron radiation, with its intensity, brightness, polarization, time structure and energy spectrum offer an unequalled probe of matter in all its states. The decades since have seen the development of a wide range of associated experimental techniques which harness the power of this radiation, including photoemission, EXAFS, spectroscopy, imaging and, of course, protein crystallography. These in turn have been applied to studies from surface science to molecular biology. The advances using synchrotron radiation throughout the 1980s and '90s naturally had a major impact on fundamental research, particularly in unraveling the structures of large proteins and in understanding the properties of semiconductors and surfaces. Much of this work could not have been accomplished without access to one of the world's increasing number of synchrotron facilities, of which there are now approaching 100. However, industrial awareness of the opportunities afforded by the use of synchrotron radiation was restricted to the handful of major multinational corporations, primarily in Europe, the USA and Japan, whose fundamental research staff had access. While there were major programmes in certain specific areas, such as X-ray lithography for semiconductor LSI fabrication, the general level of industrial involvement was low. But today, this is changing. In protein crystallography, for example, the use of synchrotron radiation in structure determination puts the 1PX' technique on the same level as NMR in terms of its routine utility. It has become an essential tool to drug designers in biopharmaceuticals, where access to the structural data is increasingly thought of almost as a service, rather than fundamental research. Pioneering work on medical imaging

  15. Metasurface integrated high energy efficient and high linearly polarized InGaN/GaN light emitting diode.

    Science.gov (United States)

    Wang, Miao; Xu, Fuyang; Lin, Yu; Cao, Bing; Chen, Linghua; Wang, Chinhua; Wang, Jianfeng; Xu, Ke

    2017-07-06

    We proposed and demonstrated an integrated high energy efficient and high linearly polarized InGaN/GaN green LED grown on (0001) oriented sapphire with combined metasurface polarizing converter and polarizer system. It is different from those conventional polarized light emissions generated with plasmonic metallic grating in which at least 50% high energy loss occurs inherently due to high reflection of the transverse electric (TE) component of an electric field. A reflecting metasurface, with a two dimensional elliptic metal cylinder array (EMCA) that functions as a half-wave plate, was integrated at the bottom of a LED such that the back-reflected TE component, that is otherwise lost by a dielectric/metal bi-layered wire grids (DMBiWG) polarizer on the top emitting surface of the LED, can be converted to desired transverse magnetic (TM) polarized emission after reflecting from the metasurface. This significantly enhances the polarized light emission efficiency. Experimental results show that extraction efficiency of the polarized emission can be increased by 40% on average in a wide angle of ±60° compared to that with the naked bottom of sapphire substrate, or 20% compared to reflecting Al film on the bottom of a sapphire substrate. An extinction ratio (ER) of average value 20 dB within an angle of ±60° can be simultaneously obtained directly from an InGaN/GaN LED. Our results show the possibility of simultaneously achieving a high degree of polarization and high polarization extraction efficiency at the integrated device level. This advances the field of GaN LED toward energy efficiency, multi-functional applications in illumination, display, medicine, and light manipulation.

  16. Impact of polarized e- and e+ beams at a future linear collider and a Z-factory. Pt. I. Fundamentals in polarization and electroweak precision physics

    International Nuclear Information System (INIS)

    Moortgat-Pick, Gudrid

    2010-12-01

    The main goal of new physics searches at a future Linear Collider is the precise determination of the underlying new physics model. The physics potential of the ILC as well as the multi-TeV option collider CLIC have to be optimized with regard to expected results from the LHC. The exploitation of spin effects plays a crucial role in this regard. After a short status report of the Linear Collider design and physics requirements, this article explains fundamentals in polarization and provides an overview of the impact of these spin effects in electroweak precision physics. (orig.)

  17. Synchrotron radiation interferences between small dipoles at LEP

    International Nuclear Information System (INIS)

    Bovet, C.; Burns, A.; Meot, F.; Placidi, M.; Rossa, E.; Vries, J. de

    1997-06-01

    Synchrotron Radiation interferences between small dipoles in the very low (visible) frequency range have been studied at the LEP diagnostic mini-wiggler. Their understanding allowed a substantial brightness gain by adequate layout modifications. The phenomenon is described analytically in terms of time coherence effects. This serves as a basis for further detailed numerical simulations of the experiment by means of stepwise ray-tracing, and allows precise interpretation of the spectral, polarization and intensity measurements collected at LEP. It also provides guidelines for SR diagnostic at injection energy in LHC

  18. Efficient high-power narrow-linewidth all-fibred linearly polarized ytterbium laser source

    Science.gov (United States)

    Bertrand, Anthony; Liégeois, Flavien; Hernandez, Yves; Giannone, Domenico

    2012-06-01

    We report on experimental results on a high power, all-fibred, linearly polarized, mode-locked laser at 1.03 μm. The laser generates pulses of 40 ps wide at a repetition rate of 52 MHz, exhibiting 12 kW peak power. Dispersion in optical fibres is controlled to obtain both high power and narrow spectral linewidth. The average output power reached is 25 W with a spectral linewidth of 380 pm and a near diffraction limit beam (M2 < 1.2). This laser is an ideal candidate for applications like IR spectroscopy, where high peak power and narrow linewidth are required for subsequent wavelength conversion.

  19. 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

  20. Synchrotron radiation sources

    Energy Technology Data Exchange (ETDEWEB)

    van Steenbergen, A.

    1979-01-01

    As a result of the exponential growth of the utilization of synchrotron radiation for research in the domain of the material sciences, atomic and molecular physics, biology and technology, a major construction activity has been generated towards new dedicated electron storage rings, designed optimally for synchrotron radiation applications, also, expansion programs are underway at the existing facilities, such as DORIS, SPEAR, and VEPP. In this report the basic properties of synchrotron radiation will be discussed, a short overview will be given of the existing and new facilities, some aspects of the optimization of a structure for a synchrotron radiation source will be discussed and the addition of wigglers and undulators for spectrum enhancement will be described. Finally, some parameters of an optimized synchrotron radiation source will be given.

  1. The importance of non-linearities in modern proton synchrotrons

    International Nuclear Information System (INIS)

    Wilson, E.J.N.

    1977-01-01

    The paper outlines the physics and mathematics of non-linear field errors in the quide fields of accelerators, with particular reference to large accelerators such as the SPS. These non-linearities give rise to closed orbital distortions and non-linear resonances or stopbands. Both of these effects are briefly discussed and the use of resonances for slow beam extraction is also described. Another problem considered is that of chromaticity of the particle beam. The use of sextupoles to correct chromaticity and the Landau damping of beam instabilities using octupoles are also discussed. In the final section the application of Hamiltonian mechanics to non-linearities is demonstrated. The author concludes that the effect of non-linearities on particle dynamics may place a more severe limit on intensity and storage time in large rings than any other effect in transverse phase space. (B.D.)

  2. Experimental investigations of synchrotron radiation at the onset of the quantum regime

    DEFF Research Database (Denmark)

    Andersen, Kristoffer; Knudsen, Helge; Uggerhøj, Ulrik Ingerslev

    2012-01-01

    The classical description of synchrotron radiation fails at large Lorentz factors, $\\gamma$, for relativistic electrons crossing strong transverse magnetic fields $B$. In the rest frame of the electron this field is comparable to the so-called critical field $B_0 = 4.414\\cdot10^9$ T. For $\\chi = ......-field quantum electrodynamics, the experimental results are also relevant for the design of future linear colliders where beamstrahlung - a closely related process - may limit the achievable luminosity....... = \\gamma B/B_0 \\simeq 1$ quantum corrections are essential for the description of synchrotron radiation to conserve energy. With electrons of energies 10-150 GeV penetrating a germanium single crystal along the $\\langle110\\rangle$ axis, we have experimentally investigated the transition from the regime...... where classical synchrotron radiation is an adequate description, to the regime where the emission drastically changes character; not only in magnitude, but also in spectral shape. The spectrum can only be described by quantum synchrotron radiation formulas. Apart from being a test of strong...

  3. Experimental investigations of synchrotron radiation at the onset of the quantum regime

    DEFF Research Database (Denmark)

    Andersen, Kristoffer; Uggerhøj, Ulrik Ingerslev

    The classical description of synchrotron radiation fails at large Lorentz factors for relativistic electrons crossing strong transverse magnetic fields. In the rest frame of the electron this field is comparable to the so-called critical field of 4.414*109 T. When the Lorentz factor times the mag......-field quantum electrodynamics, the experimental results are also relevant for the design of future linear colliders where beamstrahlung - a closely related process - may limit the achievable luminosity....... the magnetic field is comparable to the critical field, quantum corrections are essential for the description of synchrotron radiation to conserve energy. With electrons of energies 10-150 GeV penetrating a germanium single crystal along the axis, we have experimentally investigated the transition from...... the regime where classical synchrotron radiation is an adequate description, to the regime where the emission drastically changes character; not only in magnitude, but also in spectral shape. The spectrum can only be described by quantum synchrotron radiation formulas. Apart from being a test of strong...

  4. The present status of a compact synchrotron radiation source LUNA of IHI

    International Nuclear Information System (INIS)

    Marushita, Motoharu; Oishi, Masaya; Takahashi, Mitsuyuki; Komatsu, Takahito; Mandai, Shinichi

    1993-01-01

    Synchrotron radiation is expected to apply to many fields of science and industry and we are specially interested in availability of SR for X-ray lithography. This paper presents the characteristics, the design parameters, the features and current status of LUNA. Ishikawajima-Harima Heavy Industries Co., Ltd. (IHI) has developed a compact synchrotron radiation source 'LUNA' for lithography and has successfully stored beam current at full energy. LUNA consists of a 45 MeV linear accelerator as an electron injector and an 800 MeV synchrotron as a storage ring. The construction of LUNA has been completed in April 1989 at IHI Tsuchiura facility near Tsukuba. Synchrotron Radiation was first observed at December 1989. The design goal, which is to store beam current of 50 mA with the beam lifetime of over 30 minutes, has been successfully achieved in March 1991. At present the stored beam current is 80 mA with the beam lifetime of over 5 hours. (author)

  5. Is the polarization of NGC1068 evidence for a non-thermal source

    International Nuclear Information System (INIS)

    McLean, I.S.; Aspin, C.; Heathcote, S.R.; McCaughrean, M.J.

    1983-01-01

    NGC1068 is one of the brightest galaxies included by Seyfert in his list of extragalactic objects having compact, luminous nuclei within which broad, high-excitation emission lines occur. It has been the subject of intensive studies at UV, optical, IR and radio wavelengths. Unresolved questions concern the nature and relationship of the sources of the excess flux seen in the UV and IR, their connection with the collimated jets apparent in high-resolution radio maps and their association with the extended region responsible for the broad emission lines. A further question is the location of any dust and its role in modifying the optical and UV spectrum. Observations are reported with two high-resolution optical spectro-polarimeters which throw new light on these questions. From detailed structure found in the linear polarization spectrum of the nucleus it is concluded that dilution by starlight modifies the polarization to an extent not previously appreciated. In fact the polarization of the non-stellar flux in the optical and near IR is approximately independent of wavelength (as expected for synchrotron emission or electron scattering) with a direction orthogonal to that of the radio jets; such an arrangement is reminiscent of certain quasars and radio galaxies. (author)

  6. Synchrotron radiation applications in medical research at Brookhaven National Laboratory

    International Nuclear Information System (INIS)

    Thomlinson, W.

    1997-08-01

    In the relatively short time that synchrotrons have been available to the scientific community, their characteristic beams of UV and X-ray radiation have been applied to virtually all areas of medical science which use ionizing radiation. The ability to tune intense monochromatic beams over wide energy ranges clearly differentiates these sources from standard clinical and research tools. The tunable spectrum, high intrinsic collimation of the beams, polarization and intensity of the beams make possible in-vitro and in-vivo research and therapeutic programs not otherwise possible. From the beginning of research operation at the National Synchrotron Light Source (NSLS), many programs have been carrying out basic biomedical research. At first, the research was limited to in-vitro programs such as the x-ray microscope, circular dichroism, XAFS, protein crystallography, micro-tomography and fluorescence analysis. Later, as the coronary angiography program made plans to move its experimental phase from SSRL to the NSLS, it became clear that other in-vivo projects could also be carried out at the synchrotron. The development of SMERF (Synchrotron Medical Research Facility) on beamline X17 became the home not only for angiography but also for the MECT (Multiple Energy Computed Tomography) project for cerebral and vascular imaging. The high energy spectrum on X17 is necessary for the MRT (Microplanar Radiation Therapy) experiments. Experience with these programs and the existence of the Medical Programs Group at the NSLS led to the development of a program in synchrotron based mammography. A recent adaptation of the angiography hardware has made it possible to image human lungs (bronchography). Fig. 1 schematically depicts the broad range of active programs at the NSLS

  7. Synchrotron radiation

    International Nuclear Information System (INIS)

    Knotek, M.L.

    1987-01-01

    Synchrotron radiation has had a revolutionary effect on a broad range of scientific studies, from physics, chemistry and metallurgy to biology, medicine and geoscience. The situation during the last decade has been one of very rapid growth, there is a great vitality to the field and a capability has been given to a very broad range of scientific disciplines which was undreamed of just a decade or so ago. Here we will discuss some of the properties of synchrotron radiation that makes it so interesting and something of the sources in existence today including the National Synchrotron Light Source (NSLS). The NSLS is one of the new facilities built specifically for synchrotron radiation research and the model that was developed there for involvement of the scientific community is a good one which provides some good lessons for these facilities and others

  8. The third generation French synchrotron

    International Nuclear Information System (INIS)

    Anon.

    1997-01-01

    This short paper gives a concise presentation of the SOLEIL project of the LURE synchrotron radiation national laboratory at Orsay (France). This new accelerator is devoted to replace the DCI and Super ACO rings of first and second generation, respectively. The main research domains of this project concern: the micro-fluorescence and micro-diffraction characterization of materials, and in particular the electronic components; the study of matter in extreme conditions (high temperature and high pressure); the bio-crystallography; the study of aggregates; and the manufacturing of micro-instruments for micro-electronics or medical applications. SOLEIL will be equipped with special magnetic wigglers to obtain very high brightness sources. The source will be a 336 m circumference ring for 2.5 GeV electron storage, able to produce a large spectrum synchrotron radiation. The injection system will comprise a low energy-high current linear electron accelerator and two electron beam transport lines. The installation will be buried at a 4 m depth to ensure the environmental protection and to limit vibrations. (J.S.)

  9. Optimal distribution of integration time for intensity measurements in degree of linear polarization polarimetry.

    Science.gov (United States)

    Li, Xiaobo; Hu, Haofeng; Liu, Tiegen; Huang, Bingjing; Song, Zhanjie

    2016-04-04

    We consider the degree of linear polarization (DOLP) polarimetry system, which performs two intensity measurements at orthogonal polarization states to estimate DOLP. We show that if the total integration time of intensity measurements is fixed, the variance of the DOLP estimator depends on the distribution of integration time for two intensity measurements. Therefore, by optimizing the distribution of integration time, the variance of the DOLP estimator can be decreased. In this paper, we obtain the closed-form solution of the optimal distribution of integration time in an approximate way by employing Delta method and Lagrange multiplier method. According to the theoretical analyses and real-world experiments, it is shown that the variance of the DOLP estimator can be decreased for any value of DOLP. The method proposed in this paper can effectively decrease the measurement variance and thus statistically improve the measurement accuracy of the polarimetry system.

  10. Tune modulation due to synchrotron oscillations and chromaticity, and the dynamic aperture

    International Nuclear Information System (INIS)

    Parzen, G.

    1995-01-01

    A tracking study was done of the effects of a tune modulations, due to synchrotron oscillations and the tune dependence on momentum (chromaticity), on the dynamic aperture. The studies were done using several RHIC lattices and tracking runs of about 1 x 10 6 turns. The dynamic aperture was found to decrease roughly linearly with the amplitude of the tune modulation. Lower order non-linear resonances, like the 1/3 and 1/4 resonance are not crossed because of the tune modulation. Three different cases were studied, corresponding to RHIC lattices with different β*, and with different synchrotron oscillation amplitudes. In each case, the tune modulation amplitude was varied by changing the chromaticity. In each case, roughly the same result, was found. The result found here for the effect of a tune modulation due to chromaticity may be compared with the result found for the effect of a tune modulation due to a gradient ripple in the quadrupoles. The effect of a tune modulation due to a gradient ripple appears to be about 4 times stronger than the effect of a tune modulation due to chromaticity and synchrotron oscillations

  11. The first acceleration test of polarized protons in KEK PS

    International Nuclear Information System (INIS)

    Hiramatsu, Shigenori; Sato, Hikaru; Toyama, Takeshi

    1984-03-01

    The outline of the polarized proton acceleration project at KEK and the results of the first acceleration test are described. Depolarization in the 500 MeV booster synchrotron was investigated as the first step of this program. The beam polarization was measured in the 20 MeV beam transport line from the linac to the booster and in the main ring at the injection energy. About 40 % of the linac beam polarization was kept in the main ring. This acceleration test encouraged us to proceed with this program. (author)

  12. Single-mode coherent synchrotron radiation instability

    Directory of Open Access Journals (Sweden)

    S. Heifets

    2003-06-01

    Full Text Available The microwave instability driven by the coherent synchrotron radiation (CSR has been previously studied [S. Heifets and G. V. Stupakov, Phys. Rev. ST Accel. Beams 5, 054402 (2002] neglecting effect of the shielding caused by the finite beam pipe aperture. In practice, the unstable mode can be close to the shielding threshold where the spectrum of the radiation in a toroidal beam pipe is discrete. In this paper, the CSR instability is studied in the case when it is driven by a single synchronous mode. A system of equations for the beam-wave interaction is derived and its similarity to the 1D free-electron laser theory is demonstrated. In the linear regime, the growth rate of the instability is obtained and a transition to the case of continuous spectrum is discussed. The nonlinear evolution of the single-mode instability, both with and without synchrotron damping and quantum diffusion, is also studied.

  13. Electron spin polarization induced by spin Hall effect in semiconductors with a linear in the momentum spin-orbit splitting of conduction band

    OpenAIRE

    Korenev, V. L.

    2005-01-01

    It is shown that spin Hall effect creates uniform spin polarization of electrons in semiconductor with a linear in the momentum spin splitting of conduction band. In turn, the profile of the non-uniform spin polarization accumulated at the edge of the sample oscillates in space even in the absence of an external magnetic field.

  14. Design of a beam optic for the transfer channel between the LINAC 2 and the 2.5 GeV synchrotron

    International Nuclear Information System (INIS)

    Schneider, W.

    1992-10-01

    The accelerator facility at the Physikalisches Institut of Bonn University is being extended by a linear accelerator (LINAC 2) for the preacceleration of polarized electron beams to an energy level of 20 MeV. The beam optics of the transfer channel, which guides the electrons to the injection point of the 2.5 GeV-Synchrotron, has been designed. Because the emittance of the electron beam leaving the LINAC 2 is unknown at the movement, the beam optics and the aperture of the transfer channel has been layed out for a high transmission even for the worst case scenario. The quadrupol magnets needed for focusing and matching the beam has been constructed and tested. The integration of a system for beam diagnosis and position correction in the transfer channel is planned. (orig.) [de

  15. Electron beam depolarization in a damping ring

    International Nuclear Information System (INIS)

    Minty, M.

    1993-04-01

    Depolarization of a polarized electron beam injected into a damping ring is analyzed by extending calculations conventionally applied to proton synchrotrons. Synchrotron radiation in an electron ring gives rise to both polarizing and depolarizing effects. In a damping ring, the beam is stored for a time much less than the time for self polarization. Spin flip radiation may therefore be neglected. Synchrotron radiation without spin flips, however, must be considered as the resonance strength depends on the vertical betatron oscillation amplitude which changes as the electron beam is radiation damped. An expression for the beam polarization at extraction is derived which takes into account radiation damping. The results are applied to the electron ring at the Stanford Linear Collider and are compared with numerical matrix formalisms

  16. Growth properties of poly(tetrafluoroethylene) films by synchrotron radiation ablation

    International Nuclear Information System (INIS)

    Guo, Qixin; Kugino, Takashi; Kume, Yusuke; Mitsuishi, Yoshiaki; Tanaka, Tooru; Nishi, Mitsuhiro; Ogawa, Hiroshi

    2007-01-01

    High-quality poly(tetrafluoroethylene) (PTFE) films have been grown on Si substrates by synchrotron radiation ablation of a PTFE target. Only doublet absorption structures assigned to C-F asymmetric and symmetric stretching vibrations in CF 2 groups are observed, suggesting that the CF 2 groups in the grown PTFE film are organized in an ordered manner through linear attachment. The growth rate of the PTFE films increases with increasing target temperature, while it decreases with increasing substrate temperature. It has been shown that the thickness of the PTFE film with a high-spatial-resolution structure can be easily controlled at nanometer order by changing the synchrotron radiation irradiation dose. (author)

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

    NARCIS (Netherlands)

    Brantjes, N. P. M.; Dzordzhadze, V.; Gebel, R.; Gonnella, F.; Gray, F. E.; van der Hoek, D. J.; Imig, A.; Kruithof, W. L.; Lazarus, D. M.; Lehrach, A.; Lorentz, B.; Messi, R.; Moricciani, D.; Morse, W. M.; Noid, G. A.; Onderwater, C. J. G.; Ozben, C. S.; Prasuhn, D.; Sandri, P. Levi; Semertzidis, Y. K.; da Silva e Silva, M.; Stephenson, E. J.; Stockhorst, H.; Venanzoni, G.; Versolato, O. O.

    2012-01-01

    This paper reports deuteron vector and tensor beam polarization measurements taken to investigate the systematic variations due to geometric beam misalignments and high data rates. The experiments used the In-Beam Polarimeter at the KVI-Groningen and the EDDA detector at the Cooler Synchrotron COSY

  18. ELECTROCHEMICAL CORROSION STUDY VIA LINEAR POLARIZATION IN PEAS CAN

    Directory of Open Access Journals (Sweden)

    I. M. Costa

    2016-09-01

    Full Text Available The aim of this work is to study the corrosion of tinplate can for peas. Firstly, the characterization of canning solution was made. The values of pH, conductivity, Brix, viscosity, density and content of Fe were, respectively, 5.88; 32.6 mS/cm; 6.6%; 3,42cP; 1.026 g/ml; 12.05 mg/kg. The corrosion rate in the cans was determined by linear polarization technique. The electrodes with and without varnish were analyzed in the first and fifth day of the experiment for the 3 parts of the can. The corrosion rate increased significantly when the coating was removed and the body showed a higher corrosion rate, reaching 1.7 mm/year in the absence of varnish. The microstructure of the samples was evaluated by scanning electron microscopy (SEM coupled with energy dispersive spectroscopy (EDS. The increase of iron on the surface, evidenced by energy dispersive spectroscopy (EDS may have contributed to the corrosion in the samples without varnish.

  19. Angular distribution coefficients for γ-ray polarization produced in polarized capture reactions

    International Nuclear Information System (INIS)

    Wulf, E.A.; Guillemette, J.; Weller, H.R.; Seyler, R.G.

    1999-01-01

    The previous publications have dealt with the angular momentum formalism of both linear and circularly polarized photons in (γ, x) reactions on both polarized and unpolarized targets, and the inverse (capture) reactions initiated by polarized beams. In the present work, utilizing the general formalism of Welton, the authors deal with the linear polarization of the γ-rays which are produced in capture reactions on unpolarized targets, including the possibility of having incident polarized spin 1/2 projectiles. These capture reactions are denoted by a(rvec x, rvec L)c, where rvec x is the incident polarized spin 1/2 projectile and rvec L represents the outgoing polarized γ-ray. They present here the formalism in a convenient form, display a sample table of coefficients, and illustrate its use by means of several examples. A FORTRAN code will be made available for generating similar coefficients for other reactions

  20. Polarized target physics at the Bonn electron accelerators

    International Nuclear Information System (INIS)

    Meyer, W.

    1988-12-01

    At the BONN 2.5 GeV electron synchrotron experiments with polarized nucleon targets have a long tradition. Starting with measurements of the target asymmetry in single pion photoproduction off polarized protons, resp. neutrons, the experiments have been concentrated on photodisintegration measurements of polarized deuterons. Parallel to these activities a considerable progress in the field of the target technology, e.g. cryogenics and target materials, has been made, by which all the measurements have profitted enormously. Especially the development of the new target material ammonia has allowed the first use of a polarized deuteron (ND 3 ) target in an intense electron beam. The construction of a frozen spin target, which will be used in combination with a tagged polarized photon beam, makes a new generation of polarized target experiments in photon induced reactions possible. Together with electron scattering off polarized deuterons and neutrons they will be a main activity in the physics program at the new stretcher accelerator ELSA in BONN. (orig.)

  1. Quantum pump effect induced by a linearly polarized microwave in a two-dimensional electron gas.

    Science.gov (United States)

    Song, Juntao; Liu, Haiwen; Jiang, Hua

    2012-05-30

    A quantum pump effect is predicted in an ideal homogeneous two-dimensional electron gas (2DEG) that is normally irradiated by linearly polarized microwaves (MW). Without considering effects from spin-orbital coupling or the magnetic field, it is found that a polarized MW can continuously pump electrons from the longitudinal to the transverse direction, or from the transverse to the longitudinal direction, in the central irradiated region. The large pump current is obtained for both the low frequency limit and the high frequency case. Its magnitude depends on sample properties such as the size of the radiated region, the power and frequency of the MW, etc. Through the calculated results, the pump current should be attributed to the dominant photon-assisted tunneling processes as well as the asymmetry of the electron density of states with respect to the Fermi energy.

  2. Exploring the top-Higgs FCNC couplings at polarized linear colliders with top spin observables

    Energy Technology Data Exchange (ETDEWEB)

    Melić, Blaženka; Patra, Monalisa [Institut Ruđer Bošković, Theoretical Physics Division,Bijenička 54, HR-10000 Zagreb (Croatia)

    2017-01-11

    We study the nature of flavor changing neutral couplings of the top quark with the Higgs boson and the up/charm quark in the tt̄ production at linear colliders. There are previous bounds on such tqH couplings at both, linear and hadronic colliders, with the assumption that the top couples equally to the left and the right handed fermions. In this paper we examine chirality of the tqH coupling and construct different observables which will be sensitive to it. The kinematics of the emitted q from t→qH in tt̄ production is discussed and it was found that the polar angle distribution of q is sensitive to the chiral nature of tqH couplings. The observables in the context of top-antitop spin correlations, which are sensitive to new physics in the top decay are considered using different spin-quantization bases. It was found that in particular the off-diagonal basis can be useful to distinguish among the chiral tqH couplings. The sensitivity of the unpolarized ILC in probing the couplings at the 3σ level at √s = 500 GeV and L = 500 fb{sup −1} is also studied, resulting in predicted BR(t→qH)<1.19×10{sup −3}. This limit is further improved to BR(t→qH)<8.84×10{sup −4} with the inclusion of initial beam polarization of left handed electrons and right handed positrons.

  3. Polarization of Coronal Forbidden Lines

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hao; Qu, Zhongquan [Yunnan Observatories, Chinese Academy of Sciences, Kunming, Yunnan 650011 (China); Landi Degl’Innocenti, Egidio, E-mail: sayahoro@ynao.ac.cn [Dipartimento di Astronomia e Scienza dello Spazio, Università di Firenze, Largo E. Fermi 2, I-50125 Firenze (Italy)

    2017-03-20

    Since the magnetic field is responsible for most manifestations of solar activity, one of the most challenging problems in solar physics is the diagnostics of solar magnetic fields, particularly in the outer atmosphere. To this end, it is important to develop rigorous diagnostic tools to interpret polarimetric observations in suitable spectral lines. This paper is devoted to analyzing the diagnostic content of linear polarization imaging observations in coronal forbidden lines. Although this technique is restricted to off-limb observations, it represents a significant tool to diagnose the magnetic field structure in the solar corona, where the magnetic field is intrinsically weak and still poorly known. We adopt the quantum theory of polarized line formation developed in the framework of the density matrix formalism, and synthesize images of the emergent linear polarization signal in coronal forbidden lines using potential-field source-surface magnetic field models. The influence of electronic collisions, active regions, and Thomson scattering on the linear polarization of coronal forbidden lines is also examined. It is found that active regions and Thomson scattering are capable of conspicuously influencing the orientation of the linear polarization. These effects have to be carefully taken into account to increase the accuracy of the field diagnostics. We also found that linear polarization observation in suitable lines can give valuable information on the long-term evolution of the magnetic field in the solar corona.

  4. The synchrotron radiation and its various uses in physics, chemistry and biology

    International Nuclear Information System (INIS)

    Farge, Y.

    1975-01-01

    The synchrotron radiation emitted by synchrotrons or storage rings has exceptional properties: spectral continuity from X-rays to radiofrequencies, high intensity, focussed emission in the orbit plane, polarization, time pulsed structure. For the sake of these properties, this radiation is a unique tool for spectroscopic investigations in the far UV or X-rays on atoms, molecules or solids. Time resolved spectroscopy in the nano and subnanosecond range is now available in a very broad wavelength range. In the X-ray range, these sources are introducing a revolution because they are more powerfull than the best X-ray tubes by two to four orders of magnitude; it will be very soon possible to do kinetic measurements with typical times of one second and less either by diffraction, scattering or topography [fr

  5. Rapid cycling superconducting booster synchrotron

    International Nuclear Information System (INIS)

    Dinev, D.; Agapov, N.; Butenko, A.

    2001-01-01

    The existing set of Nuclotron heavy ion sources, such as duoplasmatron, polarized deuteron, laser and electron beam ion sources permits to have ion beams over a wide range of masses. The main problem for us now is to gain high intensity of accelerator particles. It can be solved by means of multiturn injection of the low current beams into the booster, acceleration up to the intermediate energies, stripping and transferring into the main ring. A design study of this accelerator - the 250 MeV/Amu Nuclotron booster synchrotron at 1 Hz repetition rate and circumference of 84 m, has been completed. The lattice dipole and quadrupole magnets have an iron yoke coils, made of hollow superconductor, are cooled by two-phase Helium flow, as well as the Nuclotron magnets. (authors)

  6. High-flux normal incidence monochromator for circularly polarized synchrotron radiation

    International Nuclear Information System (INIS)

    Schaefers, F.; Peatman, W.; Eyers, A.; Heckenkamp, C.; Schoenhense, G.; Heinzmann, U.

    1986-01-01

    A 6.5-m normal incidence monochromator installed at the storage ring BESSY, which is optimized for a high throughput of circularly polarized off-plane radiation at moderate resolution is described. The monochromator employs two exit slits and is specially designed and used for low-signal experiments such as spin- and angle-resolved photoelectron spectroscopy on solids, adsorbates, free atoms, and molecules. The Monk--Gillieson mounting (plane grating in a convergent light beam) allows for large apertures with relatively little astigmatism. With two gratings, a flux of more than 10 11 photons s -1 bandwidth -1 (0.2--0.5 nm) with a circular polarization of more than 90% in the wavelength range from 35 to 675 nm is achieved

  7. Basis of medical accelerator. Synchrotron

    International Nuclear Information System (INIS)

    Kawachi, Kiyomitsu

    2014-01-01

    On the synchrotron as a medical accelerator, this paper introduces the basic principle, basic techniques and the like. The accelerator, when synchrotron is adopted as an ion beam radiotherapy system, is the composite accelerator composed of ion sources, injector, and synchrotron. This paper introduces the overall structure of synchrotron, and conceptually explains the basic behavior of high-frequency waves and magnetic field of synchrotron, as well as the deflection electromagnet of medical synchrotron and the operation pattern of high-frequency acceleration system. The types of synchrotron can be classified to the function combination type and function separation type, and this paper introduces the features of each type and various types of synchrotrons. It also explains beam dynamics important for ensuring the stability of beams, with a focus on the coordinate system, vertical movement, and lateral movement. In addition, it explains the incidence and outgoing of beams that are important for properly operating the accelerator, with a focus on their techniques. (A.O.)

  8. Quasi-Linear Polarized Modes in Y-Rotated Piezoelectric GaPO4 Plates

    Directory of Open Access Journals (Sweden)

    Cinzia Caliendo

    2014-07-01

    Full Text Available The propagation of both surface and flexural acoustic plate modes along y-rotated x-propagation GaPO4 piezoelectric substrates was studied for several y-cut angles: the phase velocity and coupling coefficient dispersion curves were theoretically calculated for two different electroacoustic coupling configurations. The investigation of the acoustic field profile across the plate thickness revealed the presence of thin plate modes having polarization predominantly oriented along the propagation direction, and hence suitable for operation in liquid environment. These modes include the linearly polarized Anisimkin Jr. and the quasi longitudinal plate modes, AMs and QLs, showing a phase velocity close to that of the longitudinal bulk acoustic wave propagating in the same direction. The temperature coefficient of delay (TCD of these longitudinal modes was investigated in the −20 to 420 °C temperature range, in order to identify thermally stable or low TCD cuts. The power flow angle, i.e., the angle between the phase and group velocity vectors, was also estimated to evaluate the substrate anisotropy effect on the acoustic wave propagation. The GaPO4 intrinsic properties, such as its resistance to high temperature and its chemical inertness, make it especially attractive for the development of acoustic waves-based sensors for applications in harsh liquid environment.

  9. Measurement of Coherent Emission and Linear Polarization of Photons by Electrons in the Strong Fields of Aligned Crystals

    CERN Document Server

    Apyan, A.; Badelek, B.; Ballestrero, S.; Biino, C.; Birol, I.; Cenci, P.; Connell, S.H.; Eichblatt, S.; Fonseca, T.; Freund, A.; Gorini, B.; Groess, R.; Ispirian, K.; Ketel, T.J.; Kononets, Yu.V.; Lopez, A.; Mangiarotti, A.; van Rens, B.; Sellschop, J.P.F.; Shieh, M.; Sona, P.; Strakhovenko, V.; Uggerhoj, E.; Uggerhj, Ulrik Ingerslev; Unel, G.; Velasco, M.; Vilakazi, Z.Z.; Wessely, O.; Kononets, Yu.V.

    2004-01-01

    We present new results regarding the features of high energy photon emission by an electron beam of 178 GeV penetrating a 1.5 cm thick single Si crystal aligned at the Strings-Of-Strings (SOS) orientation. This concerns a special case of coherent bremsstrahlung where the electron interacts with the strong fields of successive atomic strings in a plane and for which the largest enhancement of the highest energy photons is expected. The polarization of the resulting photon beam was measured by the asymmetry of electron-positron pair production in an aligned diamond crystal analyzer. By the selection of a single pair the energy and the polarization of individual photons could be measured in an the environment of multiple photons produced in the radiator crystal. Photons in the high energy region show less than 20% linear polarization at the 90% confidence level.

  10. A simplified edge illumination set-up for quantitative phase contrast mammography with synchrotron radiation at clinical doses

    International Nuclear Information System (INIS)

    Longo, Mariaconcetta; Rigon, Luigi; Lopez, Frances C M; Longo, Renata; Chen, Rongchang; Dreossi, Diego; Zanconati, Fabrizio

    2015-01-01

    This work presents the first study of x-ray phase contrast imaging based on a simple implementation of the edge illumination method (EIXPCi) in the field of mammography with synchrotron radiation. A simplified EIXPCi set-up was utilized to study a possible application in mammography at clinical doses. Moreover, through a novel algorithm capable of separating and quantifying absorption and phase perturbations of images acquired in EIXPCi modality, it is possible to extract quantitative information on breast images, allowing an accurate tissue identification. The study was carried out at the SYRMEP beamline of Elettra synchrotron radiation facility (Trieste, Italy), where a mastectomy specimen was investigated with the EIXPCi technique. The sample was exposed at three different energies suitable for mammography with synchrotron radiation in order to test the validity of the novel algorithm in extracting values of linear attenuation coefficients integrated over the sample thickness. It is demonstrated that the quantitative data are in good agreement with the theoretical values of linear attenuation coefficients calculated on the hypothesis of the breast with a given composition. The results are promising and encourage the current efforts to apply the method in mammography with synchrotron radiation. (note)

  11. Effects of polarization of polar semiconductor on electrical properties of poly(vinylidene fluoride-trifluoroethylene)/ZnO heterostructures

    International Nuclear Information System (INIS)

    Yamada, Hiroaki; Yoshimura, Takeshi; Fujimura, Norifumi

    2015-01-01

    The electrical properties of heterostructures composed of poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) and ZnO with different crystallographic polarities, i.e., O- and Zn-polar ZnO, were investigated. Distinct differences in the capacitance-voltage and polarization-voltage characteristics between the P(VDF-TrFE)/O- and Zn-polar ZnO were obtained in the depletion regions of ZnO. The band configurations were determined by X-ray photoelectron spectroscopy (XPS) using a synchrotron radiation beam to analyze the differences in the electrical properties of the P(VDF-TrFE)/O- and Zn-polar ZnO. The XPS spectra indicated that the valence band maximum of P(VDF-TrFE) is 2.9 and 2.7 eV higher than Zn- and O-polar ZnO, respectively. Thus, both structures have staggered band configurations with large valence band offsets, and the spontaneous polarization of ZnO is less effective on the band lineup. The electrical properties of the P(VDF-TrFE)/ZnO heterostructures are modulated through carrier generation because of the polarization-mediated interface charges and the staggered band alignments of the P(VDF-TrFE)/ZnO with a large valence band offset

  12. A search for time variability and its possible regularities in linear polarization of Be stars

    International Nuclear Information System (INIS)

    Huang, L.; Guo, Z.H.; Hsu, J.C.; Huang, L.

    1989-01-01

    Linear polarization measurements are presented for 14 Be stars obtained at McDonald Observatory during four observing runs from June to November of 1983. Methods of observation and data reduction are described. Seven of eight program stars which were observed on six or more nights exhibited obvious polarimetric variations on time-scales of days or months. The incidence is estimated as 50% and may be as high as 93%. No connection can be found between polarimetric variability and rapid periodic light or spectroscopic variability for our stars. Ultra-rapid variability on time-scale of minutes was searched for with negative results. In all cases the position angles also show variations indicating that the axis of symmetry of the circumstellar envelope changes its orientation in space. For the Be binary CX Dra the variations in polarization seems to have a period which is just half of the orbital period

  13. Proton synchrotron accelerator theory

    International Nuclear Information System (INIS)

    Wilson, E.J.N.

    1977-01-01

    This is the text of a series of lectures given as part of the CERN Academic Training Programme and primarily intended for young engineers and technicians in preparation for the running-in of the 400 GeV Super Proton Synchrotron (SPS). Following the definition of basic quantities, the problems of betatron motion and the effect of momentum spread and orbital errors on the transverse motion of the beam are reviewed. Consideration is then given to multipole fields, chromaticity and non-linear resonances. After dealing with basic relations governing longitudinal beam dynamics, the space-charge, resistive-wall and other collective effects are treated, with reference to precautions in the SPS to prevent their occurrence. (Auth.)

  14. 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.

  15. 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

  16. Synchrotron radiation

    International Nuclear Information System (INIS)

    Nave, C.; Quinn, P.; Blake, R.J.

    1988-01-01

    The paper on Synchrotron Radiation contains the appendix to the Daresbury Annual Report 1987/88. The appendix is mainly devoted to the scientific progress reports on the work at the Synchrotron Radiation Source in 1987/8. The parameters of the Experimental Stations and the index to the Scientific Reports are also included in the appendix. (U.K.)

  17. International workshop on the 'Physics of interfaces by synchrotron radiation and other high energy probes'

    International Nuclear Information System (INIS)

    Krummacher, S.; Gudat, W.

    1986-05-01

    The present 'book of abstracts' consists of the abstracts of 23 lectures, held at the international workshop on the 'Physics of interfaces by synchrotron radiation and other high energy probes', April 1986, Bad Honnef, FRG. The subjects are: The use of photoemission in the study of interfaces and adsorbates, EEL spectroscopy applications, spin polarization, photoionization processes and EXAFS. (BHO)

  18. Adapting the HSV polarization-color mapping for regions with low irradiance and high polarization.

    Science.gov (United States)

    Scott Tyo, J; Ratliff, Bradley M; Alenin, Andrey S

    2016-10-15

    Many mappings from polarization into color have been developed so that polarization information can be displayed. One of the most common of these maps the angle of linear polarization into color hue and degree of linear polarization into color saturation, while preserving the irradiance information from the polarization data. While this strategy enjoys wide popularity, there is a large class of polarization images for which it is not ideal. It is common to have images where the strongest polarization signatures (in terms of degree of polarization) occur in regions of relatively low irradiance: either in shadow in reflective bands or in cold regions in emissive bands. Since the irradiance is low, the chromatic properties of the resulting images are generally not apparent. Here we present an alternate mapping that uses the statistics of the angle of polarization as a measure of confidence in the polarization signature, then amplifies the irradiance in regions of high confidence, and leaves it unchanged in regions of low confidence. Results are shown from an LWIR and a visible spectrum imager.

  19. Synchrotron radiation facilities

    CERN Multimedia

    1972-01-01

    Particularly in the past few years, interest in using the synchrotron radiation emanating from high energy, circular electron machines has grown considerably. In our February issue we included an article on the synchrotron radiation facility at Frascati. This month we are spreading the net wider — saying something about the properties of the radiation, listing the centres where synchrotron radiation facilities exist, adding a brief description of three of them and mentioning areas of physics in which the facilities are used.

  20. Radiochromic film and polarization effects

    International Nuclear Information System (INIS)

    Yu, P.K.N.; Cheung, T.; Butson, M.J.; Cancer Services, Wollongong, NSW; Inwood, D.

    2004-01-01

    Full text: A new high sensitivity radiochromic film has been tested for its polarization properties. Gafchromic HS film has been shown to produce a relatively small (less than 3%) variation in measured optical density measured at 660nm wavelength when the light source is fully linear polarized and the film is rotated through 360 deg angle. Similar variations are seen when the detector is linearly polarized. If both light source and detector is linearly polarised variations in measured optical density can reach 15% when the film is rotated through 360 deg angle. This seems to be due to a phase shift in polarised light caused by the radiochromic film resulting in the polarised light source becoming out of phase with the polarised detector. Gafchromic HS radiochromic film produces a minimal polarization response with varying angle of rotation however we recommend that a polarization test be performed on a densitometry system to establish the extent of its polarization properties before accuracy dosimetry is performed with radiochromic HS film. Copyright (2004) Australasian College of Physical Scientists and Engineers in Medicine

  1. Spin-Polarization in Quasi-Magnetic Tunnel Junctions

    Science.gov (United States)

    Xie, Zheng-Wei; Li, Ling

    2017-05-01

    Spin polarization in ferromagnetic metal/insulator/spin-filter barrier/nonmagnetic metal, referred to as quasi-magnetic tunnel junctions, is studied within the free-electron model. Our results show that large positive or negative spin-polarization can be obtained at high bias in quasi-magnetic tunnel junctions, and within large bias variation regions, the degree of spin-polarization can be linearly tuned by bias. These linear variation regions of spin-polarization with bias are influenced by the barrier thicknesses, barrier heights and molecular fields in the spin-filter (SF) layer. Among them, the variations of thickness and heights of the insulating and SF barrier layers have influence on the value of spin-polarization and the linear variation regions of spin-polarization with bias. However, the variations of molecular field in the SF layer only have influence on the values of the spin-polarization and the influences on the linear variation regions of spin-polarization with bias are slight. Supported by the Key Natural Science Fund of Sichuan Province Education Department under Grant Nos 13ZA0149 and 16ZA0047, and the Construction Plan for Scientific Research Innovation Team of Universities in Sichuan Province under Grant No 12TD008.

  2. Using synchrotron-based FT-IR microspectroscopy to study erucamide migration in 50-micron-thick bilayer linear low-density polyethylene and polyolefin plastomer films.

    Science.gov (United States)

    Sankhe, Shilpa Y; Hirt, Douglas E

    2003-01-01

    The diffusion of additives in thick (approximately 500 microns) single layer and multilayer films has been characterized using FT-IR microspectroscopy. The objective of this research was to investigate additive migration and concentration profiles in coextruded multilayer films of industrially relevant thicknesses. In particular, the investigation focused on the migration of an erucamide slip agent in 50-micron-thick coextruded bilayer films of linear low-density polyethylene (LLDPE) and a polyolefin plastomer (POP). Erucamide concentration profiles were successfully mapped using synchrotron-based FT-IR microspectroscopy. The synchrotron radiation helped to achieve a higher spatial resolution for the thin films. Meticulous sample preparation was needed to map the thin film samples. Results with FT-IR microspectroscopy showed that the additive-concentration profiles were relatively uniform across the multilayer-film thickness irrespective of the intended initial additive distribution. For example, a bilayer planned for 1 wt % erucamide in an LLDPE layer and no erucamide in a POP layer showed significant additive migration into the POP layer at the extrusion rates used. FT-IR microspectroscopy results also showed that more erucamide migrated to the surface of a POP layer than an LLDPE layer. Attenuated total reflectance (ATR) FT-IR spectroscopy was used to confirm the time-dependent increase of erucamide surface concentration and that the increase was more pronounced at the surface of the POP layers.

  3. DISCOVERY OF POLARIZATION REVERBERATION IN NGC 4151

    Energy Technology Data Exchange (ETDEWEB)

    Gaskell, C. Martin; Shoji, Masatoshi [Department of Physics and Astronomy, University of Nebraska, Lincoln, NE 68588-0111 (United States); Goosmann, Rene W. [Observatoire astronomique de Strasbourg, 11 rue de l' Universite, F-67000 Strasbourg (France); Merkulova, Nelly I.; Shakhovskoy, Nikolay M., E-mail: martin.gaskell@uv.cl, E-mail: mshoji@astro.as.utexas.edu, E-mail: rene.goosmann@astro.unistra.fr [Crimean Astrophysical Observatory, Nauchny, Crimea 98409 (Ukraine)

    2012-04-20

    Observations of the optical polarization of NGC 4151 in 1997-2003 show variations of an order of magnitude in the polarized flux while the polarization position angle remains constant. The amplitude of variability of the polarized flux is comparable to the amplitude of variability of the total U-band flux, except that the polarized flux follows the total flux with a lag of 8 {+-} 3 days. The time lag and the constancy of the position angle strongly favor a scattering origin for the variable polarization rather than a non-thermal synchrotron origin. The orientation of the position angle of the polarized flux (parallel to the radio axis) and the size of the lag imply that the polarization arises from electron scattering in a flattened region within the low-ionization component of the broad-line region. Polarization from dust scattering in the equatorial torus is ruled out as the source of the lag in polarized flux because it would produce a larger lag and, unless the half-opening angle of the torus is >53 Degree-Sign , the polarization would be perpendicular to the radio axis. We note a long-term change in the percentage of polarization at similar total flux levels, and this could be due either to changing non-axisymmetry in the optical continuum emission or a change in the number of scatterers on a timescale of years.

  4. European Synchrotron Radiation Facility

    International Nuclear Information System (INIS)

    Buras, B.

    1985-01-01

    How a European Synchrotron Radiation Facility has developed into a detailed proposal recently accepted as the basis for construction of the facility at Grenoble is discussed. In November 1977, the General Assembly of the European Science Foundation (ESF) approved the report of the ESF working party on synchrotron radiation entitled Synchrotron Radiation - a Perspective View for Europe. This report contained as one of its principal recommendations that work should commence on a feasibility study for a European synchrotron radiation laboratory having a dedicated hard X-ray storage ring and appropriate advanced instrumentation. In order to prepare a feasibility study the European Science Foundation set up the Ad-hoc Committee on Synchrotron Radiation, which in turn formed two working groups: one for the machine and another for instrumentation. This feasibility study was completed in 1979 with the publication of the Blue Book describing in detail the so called 1979 European Synchrotron Radiation Facility. The heart of the facility was a 5 GeV electron storage ring and it was assumed that mainly the radiation from bending magnets will be used. The facility is described

  5. 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

  6. Measurement of L X-ray fluorescence cross-sections for elements with 45 ≤ Z ≤ 50 using synchrotron radiation at 8 keV

    International Nuclear Information System (INIS)

    Bonzi, Edgardo V.; Badiger, Nagappa M.; Grad, Gabriela B.; Barrea, Raul A.; Figueroa, Rodolfo G.

    2011-01-01

    The L shell fluorescence cross-sections of the elements in range 45 ≤ Z ≤ 50 have been determined at 8 keV using Synchrotron radiation. The individual L X-ray photons, Ll, Lα, Lβ I , Lβ II , Lγ I and Lγ II produced in the target were measured with high resolution Si(Li) detector. The experimental set-up provided a low background by using linearly polarized monoenergetic photon beam, improving the signal-to-noise ratio. The experimental cross-sections obtained in this work were compared with available experimental data from Scofield Krause and Scofield and Puri et al. . These experimental values closely agree with the theoretical values calculated using Scofield and Krause data, except for the case of Lγ, where values measured of this work are slighter higher.

  7. Extinction correction and synchrotron radiation

    International Nuclear Information System (INIS)

    Suortti, P.

    1983-01-01

    The primary extinction factor ysub(p) is defined as the ratio of the integrated reflection from a coherently diffracting domain to the integrated kinematical reflection from the same domain. When ysub(p) is larger than 0.5 it may be approximated by ysub(p)= exp[-(αdelta) 2 ], where α is about 0.5 and delta the average size of the coherent domain when measured in units of the extinction length Λ, delta = D/Λ. Transfer equations are applied to symmetrical Laue diffraction, and the reflectivity per unit length, sigma(epsilon) is solved from the measured reflecting ratio as a function of the rocking angle epsilon = theta -thetasub(B). Measurements with conventional x-ray sources are made on single crystal slabs of Be and Si using AgKβ, MoKα 1 and CuKα radiation. The primary extinction factor ysub(p)(epsilon) is solved from a point-by-point comparison of two measurements where the extinction length Λ is changed by varying the polarization and/or wavelength of the x-ray beam. The results show that primary and secondary extinction are strongly correlated, and that the customary assumption of independent size and orientation distributions of crystal mosaics is unjustified. The structure factors for Be and Si show close agreement with other recent measurements and calculations. The limitations of the method are discussed in length, particularly the effects of beam divergences and incoherence of the rays in the crystal. It is concluded that under typical experimental conditions the requirements of the theory are met. Practical limitations arising from the use of characteristic wavelengths and unpolarized radiation prohibit the use of the full potential of the method. The properties of a synchrotron radiation source are compared with a conventional x-ray source, and it is demonstrated that the experimental limitations can be removed by the use of synchrotron radiation. A diffraction experiment with synchrotron radiation is outlined, as well as generalization of the

  8. Chemistry with synchrotron radiation

    International Nuclear Information System (INIS)

    Preses, J.; Grover, J.R.; White, M.G.; Kvick, A.

    1990-01-01

    An accidental by-product of high-energy physics, synchrotron radiation, has emerged as one of the most powerful tools for the understanding of chemical reactions. Advances made by using synchrotron radiation in physical chemistry are reviewed herein. Descriptions of experiments exploiting the many ways that synchrotron radiation can be manipulated are presented. These manipulations include intensification of the radiation and compression or shifting of its spectral structure. Combinations of the use of synchrotron radiation, which provides access to very short wavelengths and is, at the same time, continuously and easily tunable, with laser radiation, which offers much higher resolution and much more intense radiation per pulse, but is difficult to tune in the ultraviolet region of the spectra, gives the chemist a way to map a molecule's potential energy curve, to note the lengths and strengths of chemical bonds, and to predict and explain novel reactions of more complex molecules. The use of diffraction of x-rays to study the spacing of atoms in crystals is discussed. Various applications of synchrotron radiation to studies of the fluorescence of hydrocarbons and to the chiral dichroism studies of other natural products like DNA and RNA are described. Methods for enhancing synchrotron light sources by insertion devices, such as wigglers and undulators, that increase the available photo flux and construction of new sources of synchrotron radiation are mentioned

  9. Cross section and linear polarization of tagged photons

    International Nuclear Information System (INIS)

    Asai, J.; Caplan, H.S.; Skopik, D.M.; DelBianco, W.; Maximon, L.C.

    1988-01-01

    Formulae for bremsstrahlung cross sections and polarizations are usually presented in coordinate systems not very suitable for application by experimental physicists to devices such as photon-tagging monochromators. In this paper the transformations between the different coordinate systems are presented, along with examples of the calculated cross sections and polarizations in a form convenient from the experimental standpoint. These examples also give the predicted characteristics of the photon tagger currently under construction at the Saskatchewan Accelerator Laboratory. (16 refs., 19 figs., tab.)

  10. Impact of the Wiggler Coherent Synchrotron Radiation Impedance on the Beam Instability

    International Nuclear Information System (INIS)

    Wu, Juhao

    2003-01-01

    Coherent Synchrotron Radiation (CSR) can play an important role by not only increasing the energy spread and emittance of a beam, but also leading to a potential instability. Previous studies of the CSR induced longitudinal instability were carried out for the CSR impedance due to dipole magnets. However, many storage rings include long wigglers where a large fraction of the synchrotron radiation is emitted. This includes high-luminosity factories such as DAPHNE, PEP-II, KEK-B, and CESR-C as well as the damping rings of future linear colliders. In this paper, the instability due to the CSR impedance from a wiggler is studied assuming a large wiggler parameter K. The primary consideration is a low frequency microwave-like instability, which arises near the pipe cut-off frequency. Detailed results are presented on the growth rate and threshold for the damping rings of several linear collider designs. Finally, the optimization of the relative fraction of damping due to the wiggler systems is discussed for the damping rings

  11. Relativistic Turbulence with Strong Synchrotron and Synchrotron-Self-Compton Cooling

    Science.gov (United States)

    Uzdensky, D. A.

    2018-03-01

    Many relativistic plasma environments in high-energy astrophysics, including pulsar wind nebulae, hot accretion flows onto black holes, relativistic jets in active galactic nuclei and gamma-ray bursts, and giant radio lobes, are naturally turbulent. The plasma in these environments is often so hot that synchrotron and inverse-Compton (IC) radiative cooling becomes important. In this paper we investigate the general thermodynamic and radiative properties (and hence the observational appearance) of an optically thin relativistically hot plasma stirred by driven magnetohydrodynamic (MHD) turbulence and cooled by radiation. We find that if the system reaches a statistical equilibrium where turbulent heating is balanced by radiative cooling, the effective electron temperature tends to attain a universal value θ = kT_e/m_e c^2 ˜ 1/√{τ_T}, where τT = neσTL ≪ 1 is the system's Thomson optical depth, essentially independent of the strength of turbulent driving and hence of the magnetic field. This is because both MHD turbulent dissipation and synchrotron cooling are proportional to the magnetic energy density. We also find that synchrotron self-Compton (SSC) cooling and perhaps a few higher-order IC components are automatically comparable to synchrotron in this regime. The overall broadband radiation spectrum then consists of several distinct components (synchrotron, SSC, etc.), well separated in photon energy (by a factor ˜ τ_T^{-1}) and roughly equal in power. The number of IC peaks is checked by Klein-Nishina effects and depends logarithmically on τT and the magnetic field. We also examine the limitations due to synchrotron self-absorption, explore applications to Crab PWN and blazar jets, and discuss links to radiative magnetic reconnection.

  12. 2.43 kW narrow linewidth linearly polarized all-fiber amplifier based on mode instability suppression

    Science.gov (United States)

    Su, Rongtao; Tao, Rumao; Wang, Xiaolin; Zhang, Hanwei; Ma, Pengfei; Zhou, Pu; Xu, Xiaojun

    2017-08-01

    We demonstrate an experimental study on scaling mode instability (MI) threshold in fiber amplifiers based on fiber coiling. The experimental results show that coiling the active fiber in the cylindrical spiral shape is superior to the coiling in the plane spiral shape. When the polarization maintained Yb-doped fiber (PM YDF: with a core/inner-cladding diameter of 20/400 µm) is coiled on an aluminous plate with a bend diameter of 9-16 cm, the MI threshold is ~1.55 kW. When such a PM YDF is coiled on an aluminous cylinder with diameter of 9 cm, no MI is observed at the output power of 2.43 kW, which is limited by the available pump power. The spectral width and polarization extinction ratio is 0.255 nm and 18.3 dB, respectively, at 2.43 kW. To the best of our knowledge, this is the highest output power from a linear polarized narrow linewidth all-fiberized amplifier. By using a theoretical model, the potential MI-free scaling capability in such an amplifier is estimated to be 3.5 kW.

  13. Polarized high-brilliance and high-resolution soft x-ray source at ELETTRA: The performance of beamline BACH

    International Nuclear Information System (INIS)

    Zangrando, M.; Zacchigna, M.; Finazzi, M.; Cocco, D.; Rochow, R.; Parmigiani, F.

    2004-01-01

    BACH, a soft x-ray beamline for polarization-dependent experiments at the Italian synchrotron radiation facility ELETTRA, was recently completed and characterized. Its performance, in terms of energy resolution, flux and polarization, is presented. Based on two APPLE II undulators, BACH covers the energy range between 35 and 1600 eV with the control of the light polarization. The monochromator is equipped with four gratings and allows one to work either in a high resolution or in a high flux mode. After the monochromator, the beamline is split into two branches with different refocusing properties. One is optimized to exploit the performance of the soft x-ray spectrometer (ComIXS) available at the beamline. Resolving powers between 12000 at 90 eV photon energy and 6600 near 867 eV were achieved using the high-resolution gratings and the smallest available slit width (10 μm). For the high-brilliance grating, which works between 290 and 1600 eV, resolving powers between 7000 at 400 eV and 2200 at 867 eV were obtained. The flux in the experimental chamber, measured with the high-resolution gratings for linearly polarized light at the best achievable resolution, ranges between 4x10 11 photons/s at 125 eV and 2x10 10 photons/s between 900 and 1250 eV. In circularly polarized mode the flux is two times larger for energies up to 380 eV. A gain of nearly one order of magnitude is obtained for the high-brilliance grating, in accordance with theoretical predictions. Flux beyond 1.3x10 11 photons/s was measured up to 1300 eV, and thus over nearly the complete energy range covered by this high-brilliance grating, with a maximum of 1.6x10 11 photons/s between 800 and 1100 eV. First results from polarization measurements confirm a polarization above 99.7% for both linearly and circularly polarized modes at low energies. Circular dichroism experiments indicate a circular polarization beyond 90% at the Fe L 2 /L 3 edge near 720 eV

  14. 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.

  15. Polarity effects in the x-ray photoemission of ZnO and other wurtzite semiconductors

    International Nuclear Information System (INIS)

    Allen, M. W.; Zemlyanov, D. Y.; Waterhouse, G. I. N.; Metson, J. B.; Veal, T. D.; McConville, C. F.; Durbin, S. M.

    2011-01-01

    Significant polarity-related effects were observed in the near-surface atomic composition and valence band electronic structure of ZnO single crystals, investigated by x-ray photoemission spectroscopy using both Al K α (1486.6 eV) and synchrotron radiation (150 to 1486 eV). In particular, photoemission from the lowest binding energy valence band states was found to be significantly more intense on the Zn-polar face compared to the O-polar face. This is a consistent effect that can be used as a simple, nondestructive indicator of crystallographic polarity in ZnO and other wurtzite semiconductors.

  16. Synchrotron radiation from protons

    International Nuclear Information System (INIS)

    Dutt, S.K.

    1992-12-01

    Synchrotron radiation from protons, though described by the same equations as the radiation from electrons, exhibits a number of interesting features on account of the parameters reached in praxis. In this presentation, we shall point out some of the features relating to (i) normal synchrotron radiation from dipoles in proton machines such as the High Energy Booster and the Superconducting Super Collider; (ii) synchrotron radiation from short dipoles, and its application to light monitors for proton machines, and (iii) synchrotron radiation from undulators in the limit when, the deflection parameter is much smaller than unity. The material for this presentation is taken largely from the work of Hofmann, Coisson, Bossart, and their collaborators, and from a paper by Kim. We shall emphasize the qualitative aspects of synchrotron radiation in the cases mentioned above, making, when possible, simple arguments for estimating the spectral and angular properties of the radiation. Detailed analyses can be found in the literature

  17. Future Synchrotron Radiation Sources

    CERN Document Server

    Winick, Herman

    2003-01-01

    Sources of synchrotron radiation (also called synchrotron light) and their associated research facilities have experienced a spectacular growth in number, performance, and breadth of application in the past two to three decades. In 1978 there were eleven electron storage rings used as light sources. Three of these were small rings, all below 500 mega-electron volts (MeV), dedicated to this purpose; the others, with energy up to 5 giga-electron volts (GeV), were used parasitically during the operation of the ring for high energy physics research. In addition, at that time synchrotron radiation from nine cyclic electron synchrotrons, with energy up to 5 GeV, was also used parasitically. At present no cyclic synchrotrons are used, while about 50 electron storage rings are in operation around the world as fully dedicated light sources for basic and applied research in a wide variety of fields. Among these fields are structural molecular biology, molecular environmental science, materials, analytic chemistry, micr...

  18. Coronary angiography using synchrotron radiation

    International Nuclear Information System (INIS)

    Akatsuka, Takao; Hiranaka, Yukio; Takeda, Tohru; Hyodo, Kazuyuki.

    1990-01-01

    Invasive coronary angiography is the imaging technique of choice for diagnosis of ischemic heart disease. Recently, the application of synchrotron radiation in coronary angiography has been investigated in the world, with the aim of developing the noninvasive technique for visualizing the heart. In this article, backgrounds and present situation of coronary angiography using synchrotron radiation are reviewed. Firstly, visual imaging techniques of the cardiovascular system are discussed in terms of angiography and digital subtraction angiography (DSA). Conventional temporal, energy, and hybrid subtraction modes used in DSA are referred to. Secondly, the application of synchrotron radiation is presented, focusing on the property of synchrotron radiation and K-edge subtraction angiography. Two kinds of synchrotron radiation beam methods are outlined. Interpretation of image data and various subtraction procedures remain unestablished. There is much to be done before coronary angiography using synchrotron radiation comes into a clinical practice. (N.K.)

  19. Anisotropy and linear polarization of radiative processes in energetic ion-atom collisions; Untersuchung zur Anisotropie und linearen Polarisation radiativer Prozesse in energiereichen Ion-Atom-Stoessen

    Energy Technology Data Exchange (ETDEWEB)

    Weber, Guenter

    2010-06-16

    In the present thesis the linear polarization of radiation emitted in energetic ion-atom collisions at the ESR storage ring was measured by applying a novel type of position, timing and energy sensitive X-ray detector as a Compton polarimeter. In contrast to previous measurements, that mainly concentrate on studies of the spectral and angular distribution, the new detectors allowed the first polarization study of the Ly-{alpha}{sub 1} radiation (2p{sub 3/2}{yields}1s{sub 1/2}) in U{sup 91+}. Owing to the high precision of the polarimeters applied here, the experimental results indicate a significant depolarization of the Ly-{alpha}{sub 1} radiation caused by the interference of the E1 and M2 transition branches. Moreover, the current investigation shows that measurements of the linear polarization in combination with angular distribution studies provide a model-independent probe for the ratio of the E1 and M2 transition amplitudes and, consequently, of the corresponding transition probabilities. In addition, a first measurement of the linear polarization as well as an angular distribution study of the electron-nucleus Bremsstrahlung arising from ion-atom collisions was performed. The experimental results obtained were compared to exact relativistic calculations and, in case of the Bremsstrahlung, to a semirelativistic treatment. In general, good agreement was found between theoretical predictions and experimental findings. (orig.)

  20. Synchrotron radiation research

    International Nuclear Information System (INIS)

    Markus, N.

    1995-01-01

    In the many varied application fields of accelerators, synchrotron radiation ranks as one of the most valuable and widely useful tools. Synchrotron radiation is produced in multi-GeV electron synchrotrons and storage rings, and emerges tangentially in a narrow vertical fan. Synchrotron radiation has been used extensively for basic studies and, more recently, for applied research in the chemical, materials, biotechnology and pharmaceutical industries. Initially, the radiation was a byproduct of high energy physics laboratories but the high demand soon resulted in the construction of dedicated electron storage rings. The accelerator technology is now well developed and a large number of sources have been constructed, with energies ranging from about 1.5 to 8 GeV including the 6 GeV European Synchrotron Radiation Facility (ESRF) source at Grenoble, France. A modern third-generation synchrotron radiation source has an electron storage ring with a complex magnet lattice to produce ultra-low emittance beams, long straights for 'insertion devices', and 'undulator' or 'wiggler' magnets to generate radiation with particular properties. Large beam currents are necessary to give high radiation fluxes and long beam lifetimes require ultra high vacuum systems. Industrial synchrotron radiation research programmes use either Xray diffraction or spectroscopy to determine the structures of a wide range of materials. Biological and pharmaceutical applications study the functions of various proteins. With this knowledge, it is possible to design molecules to change protein behaviour for pharmaceuticals, or to configure more active proteins, such as enzymes, for industrial processes. Recent advances in molecular biology have resulted in a large increase in protein crystallography studies, with researchers using crystals which, although small and weakly diffracting, benefit from the high intensity. Examples with commercial significance include the study of

  1. Uses of synchrotron radiation

    International Nuclear Information System (INIS)

    Gordon, B.M.

    1982-01-01

    X-ray fluorescence has long been used as a technique for elemental analysis. X-ray fluorescence techniques have a number of features that make them attractive for application to biomedical samples. In the past few years synchrotron radiation x-ray sources have been developed and, because of their properties, their use can improve the sensitivity for trace element analysis by two to three orders of magnitude. Also, synchrotron radiation will make possible an x-ray microprobe with resolution in the micrometer range. The National Synchrotron Light Source (NSLS), a dedicated synchrotron radiation source recently built at Brookhaven National Laboratory, will have a facility for trace element analysis by x-ray fluorescence and will be available to all interested users

  2. Synchrotron radiation

    International Nuclear Information System (INIS)

    Norman, D.; Walker, R.P.; Durham, P.J.; Ridley, P.A.

    1986-01-01

    The paper on synchrotron radiation is the appendix to the Daresbury (United Kingdom) annual report, 1985/86. The bulk of the volume is made up of the progress reports for the work carried out during the year under review using the Synchrotron Radiation Source (SRS) at Daresbury. The Appendix also contains: the scientific programmes at the the SRS, progress on beamlines, instrumentation and computing developments, and activities connected with accelerator development. (U.K.)

  3. Polarized neutron experiments and its application at KEK

    International Nuclear Information System (INIS)

    Takeda, Masayasu

    1998-01-01

    A polarized cold neutron spectrometer was installed at Japan National Laboratory for High Energy Synchrotron (KEK) for the study of mesoscopic magnetism. Some experiments performed by the spectrometer were reviewed. Neutron wave-length dependent depolarization method was applied to the reentrant spin glass Fe-Al alloy and the difference of the depolarization between zero-field cooling and filed cooling was observed. The lower critical field, H c1 , of a high Tc superconductor, YBCO, was determined from the wave-length dependence of the polarization of neutrons. In PdFe fine particles, the existence of the non-magnetic shell was found and the thickness of the shell was determined by using polarized neutron small angle scattering. Magnetic properties of the surface and interlayer boundaries were thrown light upon Fe/Cr multilayer thin films. (Y. Kazumata)

  4. Measurement of the positron polarization at an helical undulator based positron source for the international linear collider ILC. The E-166 experiment at SLAC

    Energy Technology Data Exchange (ETDEWEB)

    Karim, Laihem

    2008-06-05

    A helical undulator based polarized positron source is forseen at a future International Linear Collider (ILC). The E-166 experiment has tested this scheme using a one meter long, short-period, pulsed helical undulator installed in the Final Focus Test Beam (FFTB) at SLAC. A low-emittance 46.6 GeV electron beam passing through this undulator generated circularly polarized photons with energies up to about 8 MeV. The generated photons of several MeV with circular polarization are then converted in a relatively thin target to generate longitudinally polarized positrons. Measurements of the positron polarization have been performed at 5 different energies of the positrons. In addition electron polarization has been determined for one energy point. For a comparison of the measured asymmetries with the expectations detailed simulations were necessary. This required upgrading GEANT4 to include the dominant polarization dependent interactions of electrons, positrons and photons in matter. The measured polarization of the positrons agrees with the expectations and is for the energy point with the highest polarization at 6MeV about 80%. (orig.)

  5. Stanford Synchrotron Radiation Laboratory 1991 activity report. Facility developments January 1991--March 1992

    International Nuclear Information System (INIS)

    Cantwell, K.; St. Pierre, M.

    1992-01-01

    SSRL is a national facility supported primarily by the Department of Energy for the utilization of synchrotron radiation for basic and applied research in the natural sciences and engineering. It is a user-oriented facility which welcomes proposals for experiments from all researchers. The synchrotron radiation is produced by the 3.5 GeV storage ring, SPEAR, located at the Stanford Linear Accelerator Center (SLAC). SPEAR is a fully dedicated synchrotron radiation facility which operates for user experiments 7 to 9 months per year. SSRL currently has 24 experimental stations on the SPEAR storage ring. There are 145 active proposals for experimental work from 81 institutions involving approximately 500 scientists. There is normally no charge for use of beam time by experimenters. This report summarizes the activity at SSRL for the period January 1, 1991 to December 31, 1991 for research. Facility development through March 1992 is included

  6. Stanford Synchrotron Radiation Laboratory 1991 activity report. Facility developments January 1991--March 1992

    Energy Technology Data Exchange (ETDEWEB)

    Cantwell, K.; St. Pierre, M. [eds.

    1992-12-31

    SSRL is a national facility supported primarily by the Department of Energy for the utilization of synchrotron radiation for basic and applied research in the natural sciences and engineering. It is a user-oriented facility which welcomes proposals for experiments from all researchers. The synchrotron radiation is produced by the 3.5 GeV storage ring, SPEAR, located at the Stanford Linear Accelerator Center (SLAC). SPEAR is a fully dedicated synchrotron radiation facility which operates for user experiments 7 to 9 months per year. SSRL currently has 24 experimental stations on the SPEAR storage ring. There are 145 active proposals for experimental work from 81 institutions involving approximately 500 scientists. There is normally no charge for use of beam time by experimenters. This report summarizes the activity at SSRL for the period January 1, 1991 to December 31, 1991 for research. Facility development through March 1992 is included.

  7. The Stanford Linear Collider

    International Nuclear Information System (INIS)

    Emma, P.

    1995-01-01

    The Stanford Linear Collider (SLC) is the first and only high-energy e + e - linear collider in the world. Its most remarkable features are high intensity, submicron sized, polarized (e - ) beams at a single interaction point. The main challenges posed by these unique characteristics include machine-wide emittance preservation, consistent high intensity operation, polarized electron production and transport, and the achievement of a high degree of beam stability on all time scales. In addition to serving as an important machine for the study of Z 0 boson production and decay using polarized beams, the SLC is also an indispensable source of hands-on experience for future linear colliders. Each new year of operation has been highlighted with a marked improvement in performance. The most significant improvements for the 1994-95 run include new low impedance vacuum chambers for the damping rings, an upgrade to the optics and diagnostics of the final focus systems, and a higher degree of polarization from the electron source. As a result, the average luminosity has nearly doubled over the previous year with peaks approaching 10 30 cm -2 s -1 and an 80% electron polarization at the interaction point. These developments as well as the remaining identifiable performance limitations will be discussed

  8. Ring artifacts removal from synchrotron CT image slices

    International Nuclear Information System (INIS)

    Wei Zhouping; Chapman, Dean; Wiebe, Sheldon

    2013-01-01

    Ring artifacts can occur in reconstructed images from x-ray Computerized Tomography (CT) as full or partial concentric rings superimposed on the scanned structures. Due to the data corruption by those ring artifacts in CT images, qualitative and quantitative analysis of these images are compromised. In this paper, we propose to correct the ring artifacts on the reconstructed synchrotron radiation (SR) CT image slices. The proposed correction procedure includes the following steps: (1). transform the reconstructed CT images into polar coordinates; (2) apply discrete two-dimensional (2D) wavelet transform to the polar image to decompose it into four image components: low pass band image component, as well as the components from horizontal, vertical and diagonal details bands; (3). apply 2D Fourier transform to the vertical details band image component only, since the ring artifacts become vertical lines in the polar coordinates; (4). apply Gaussian filtering in Fourier domain along the abscissa direction to suppress the vertical lines, since the information of the vertical lines in Fourier domain is completely condensed to that direction; (5). perform inverse Fourier transform to get the corrected vertical details band image component; (6). perform inverse wavelet transform to get the corrected polar image; (7). transform the corrected polar image back to Cartesian coordinates to get the CT image slice with reduced ring artifacts. This approach has been successfully used on CT data acquired from the Biomedical Imaging and Therapy (BMIT) beamline in Canadian Light Source (CLS), and the results show that the ring artifacts in original SR CT images have been effectively suppressed with all the structure information in the image preserved.

  9. Examination for optimization of synchrotron radiation spectrum for the x ray depth lithography

    Science.gov (United States)

    Dany, Raimund

    1992-06-01

    The effect of reducing the vertical distribution of synchrotron radiation on its spectral distribution is examined through resin irradiation. The resulting filter effect is compared to that of absorption filters. Transmission coefficients of titanium, gold, and polyamide were calculated from linear absorption coefficients with the Beer law. The use of a diaphragm in X-ray depth lithography, which is the first step of the LIGA (Lithography Galvanoforming Molding) process, is discussed. A calorimetric device for determining the synchrotron radiation power and distribution was developed and tested. Measurements at the ELSA storage ring show a strong dependence of the vertical emittance on the electron current.

  10. Charged particle beam monitoring by means of synchrotron radiation

    International Nuclear Information System (INIS)

    Panasyuk, V.S.; Anevskij, S.I.

    1984-01-01

    Optical methods for monitoring the number of accelerated electrons and electron energy by means of beam synchrotron radiation (SR) as well as peculiarities of SR characteristics of beams with a small radius of the orbit are considered. Optical methods for charged particle beam monitoring are shown to ensure operative and precise monitoring the number of particles and particle energy. SR sources with large axial dimensions of an electron beam have specific spectral angular and polarization characteristics. If electron angular distribution at deflection from the median plane is noticeably wider than angular distribution of SR of a certain electron, relative SR characteristics of these soUrces are calculated with high accuracy

  11. Dispersion of linearly polarized electromagnetic wave in magnetized quantum plasma

    International Nuclear Information System (INIS)

    Singh, Abhisek Kumar; Kumar, Punit

    2015-01-01

    The generation of harmonic radiation is significant in terms of laser-plasma interaction and has brought interesting notice due to the diversity of its applications. The odd harmonics of laser frequency are generated in the majority of laser interactions with homogenous plasma. It has been remarked that second harmonic generation takes place in the presence of density gradient which gives rise to perturbation in the electron density at the laser frequency. The density perturbation coupled with the quiver motion of the electrons produces a source current at the second harmonic frequency. Second harmonic generation has also been related with filamentation. In the present paper, a study of second harmonic generation by propagation of a linearly polarized electromagnetic wave through homogeneous high density quantum plasma in the presence of transverse magnetic field. The nonlinear current density and dispersion relations for the fundamental and second harmonic frequencies have been obtained using the recently developed quantum hydrodynamic (QHD) model. The effect of quantum Bohm potential, Fermi pressure and the electron spin have been taken into account. The second harmonic is found to be less dispersed than the first. (author)

  12. Synchrotron radiation

    International Nuclear Information System (INIS)

    Poole, M.W.; Lea, K.R.

    1982-01-01

    A report is given on the work involving the Synchrotron Radiation Division of the Daresbury Laboratory during the period January 1981 - March 1982. Development of the source, beamlines and experimental stations is described. Progress reports from individual investigators are presented which reveal the general diversity and interdisciplinary nature of the research which benefits from access to synchrotron radiation and the associated facilities. Information is given on the organisation of the Division and publications written by the staff are listed. (U.K.)

  13. National Synchrotron Light Source

    International Nuclear Information System (INIS)

    van Steenbergen, A.

    1979-01-01

    The National Synchrotron Light Source comprises two high intensity electron storage rings for the generation of intense fluxes of synchrotron radiation in the vuv wavelength domain (700 MeV e - ring) and in the x-ray wavelength domain (2.5 GeV e - ring). A description is presented of the basic facility and the characteristics of the synchrotron radiation sources. The present plans for specific beam lines will be enumerated and the planned use of beam wigglers and undulators will be discussed

  14. 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.

  15. Nuclear resonant scattering of synchrotron radiation: Applications in magnetism of layered structures

    International Nuclear Information System (INIS)

    Schlage, Kai; Röhlsberger, Ralf

    2013-01-01

    Highlights: •Depth-resolved determination of magnetic spin structures. •Isotopic probe layers allow for probing selected depths in the sample. •High sensitivity to magnetic domain patterns via diffuse scattering. -- Abstract: Nuclear resonant scattering of synchrotron radiation has become an established tool within condensed-matter research. Synchrotron radiation with its outstanding brilliance, transverse coherence and polarization has opened this field for many unique studies, for fundamental research in the field of light-matter interaction as well as for materials science. This applies in particular for the electronic and magnetic structure of very small sample volumes like micro- and nano-structures and samples under extreme conditions of temperature and pressure. This article is devoted to the application of the technique to nanomagnetic systems such as thin films and multilayers. After a basic introduction into the method, a number of our experiments are presented to illustrate how magnetic spin structures within such layer systems can be revealed

  16. Radiative polarization in high-energy storage rings

    International Nuclear Information System (INIS)

    Mane, S.R.

    1989-01-01

    Electron and positron beams circulating in high-energy storage rings become spontaneously polarized by the emission of synchrotron radiation. The asymptotic degree of polarization that can be attained is strongly affected by so-called depolarizing resonances. Detailed experimental measurements of the polarization were made SPEAR about ten years ago, but due to lack of a suitable theory only a limited theoretical fit to the data has so far been achieved. The author presents a general formalism for calculating depolarizing resonances, which has been coded into a computer program called SMILE, and use it to fit the SPEAR data. By the use of suitable approximations, the author is able to fit both higher order and nonlinear resonances, and thereby to interpret many hitherto unexplained features in the data, and to resolve a puzzle concerning the asymmetry of certain resonance widths seen in the data. 18 refs., 2 figs

  17. Interfacial B-site atomic configuration in polar (111) and non-polar (001) SrIrO3/SrTiO3 heterostructures

    Science.gov (United States)

    Anderson, T. J.; Zhou, H.; Xie, L.; Podkaminer, J. P.; Patzner, J. J.; Ryu, S.; Pan, X. Q.; Eom, C. B.

    2017-09-01

    The precise control of interfacial atomic arrangement in ABO3 perovskite heterostructures is paramount, particularly in cases where the subsequent electronic properties of the material exhibit geometrical preferences along polar crystallographic directions that feature inevitably complex surface reconstructions. Here, we present the B-site interfacial structure in polar (111) and non-polar (001) SrIrO3/SrTiO3 interfaces. The heterostructures were examined using scanning transmission electron microscopy and synchrotron-based coherent Bragg rod analysis. Our results reveal the preference of B-site intermixing across the (111) interface due to the polarity-compensated SrTiO3 substrate surface prior to growth. By comparison, the intermixing at the non-polar (001) interface is negligible. This finding suggests that the intermixing may be necessary to mitigate epitaxy along heavily reconstructed and non-stoichiometric (111) perovskite surfaces. Furthermore, this preferential B-site configuration could allow the geometric design of the interfacial perovskite structure and chemistry to selectively engineer the correlated electronic states of the B-site d-orbital.

  18. Interfacial B-site atomic configuration in polar (111 and non-polar (001 SrIrO3/SrTiO3 heterostructures

    Directory of Open Access Journals (Sweden)

    T. J. Anderson

    2017-09-01

    Full Text Available The precise control of interfacial atomic arrangement in ABO3 perovskite heterostructures is paramount, particularly in cases where the subsequent electronic properties of the material exhibit geometrical preferences along polar crystallographic directions that feature inevitably complex surface reconstructions. Here, we present the B-site interfacial structure in polar (111 and non-polar (001 SrIrO3/SrTiO3 interfaces. The heterostructures were examined using scanning transmission electron microscopy and synchrotron-based coherent Bragg rod analysis. Our results reveal the preference of B-site intermixing across the (111 interface due to the polarity-compensated SrTiO3 substrate surface prior to growth. By comparison, the intermixing at the non-polar (001 interface is negligible. This finding suggests that the intermixing may be necessary to mitigate epitaxy along heavily reconstructed and non-stoichiometric (111 perovskite surfaces. Furthermore, this preferential B-site configuration could allow the geometric design of the interfacial perovskite structure and chemistry to selectively engineer the correlated electronic states of the B-site d-orbital.

  19. SYNCHROTRON HEATING BY A FAST RADIO BURST IN A SELF-ABSORBED SYNCHROTRON NEBULA AND ITS OBSERVATIONAL SIGNATURE

    International Nuclear Information System (INIS)

    Yang, Yuan-Pei; Dai, Zi-Gao; Zhang, Bing

    2016-01-01

    Fast radio bursts (FRBs) are mysterious transient sources. If extragalactic, as suggested by their relative large dispersion measures, their brightness temperatures must be extremely high. Some FRB models (e.g., young pulsar model, magnetar giant flare model, or supra-massive neutron star collapse model) suggest that they may be associated with a synchrotron nebula. Here we study a synchrotron-heating process by an FRB in a self-absorbed synchrotron nebula. If the FRB frequency is below the synchrotron self-absorption frequency of the nebula, electrons in the nebula would absorb FRB photons, leading to a harder electron spectrum and enhanced self-absorbed synchrotron emission. In the meantime, the FRB flux is absorbed by the nebula electrons. We calculate the spectra of FRB-heated synchrotron nebulae, and show that the nebula spectra would show a significant hump in several decades near the self-absorption frequency. Identifying such a spectral feature would reveal an embedded FRB in a synchrotron nebula

  20. SYNCHROTRON HEATING BY A FAST RADIO BURST IN A SELF-ABSORBED SYNCHROTRON NEBULA AND ITS OBSERVATIONAL SIGNATURE

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yuan-Pei; Dai, Zi-Gao [School of Astronomy and Space Science, Nanjing University, Nanjing 210093 (China); Zhang, Bing, E-mail: zhang@physics.unlv.edu [Department of Physics and Astronomy, University of Nevada, Las Vegas, NV 89154 (United States)

    2016-03-01

    Fast radio bursts (FRBs) are mysterious transient sources. If extragalactic, as suggested by their relative large dispersion measures, their brightness temperatures must be extremely high. Some FRB models (e.g., young pulsar model, magnetar giant flare model, or supra-massive neutron star collapse model) suggest that they may be associated with a synchrotron nebula. Here we study a synchrotron-heating process by an FRB in a self-absorbed synchrotron nebula. If the FRB frequency is below the synchrotron self-absorption frequency of the nebula, electrons in the nebula would absorb FRB photons, leading to a harder electron spectrum and enhanced self-absorbed synchrotron emission. In the meantime, the FRB flux is absorbed by the nebula electrons. We calculate the spectra of FRB-heated synchrotron nebulae, and show that the nebula spectra would show a significant hump in several decades near the self-absorption frequency. Identifying such a spectral feature would reveal an embedded FRB in a synchrotron nebula.

  1. Scattering of a cross-polarized linear wave by a soliton at an optical event horizon in a birefringent nanophotonic waveguide.

    Science.gov (United States)

    Ciret, Charles; Gorza, Simon-Pierre

    2016-06-15

    The scattering of a linear wave on an optical event horizon, induced by a cross-polarized soliton, is experimentally and numerically investigated in integrated structures. The experiments are performed in a dispersion-engineered birefringent silicon nanophotonic waveguide. In stark contrast with copolarized waves, the large difference between the group velocity of the two cross-polarized waves enables a frequency conversion almost independent of the soliton wavelength. It is shown that the generated idler is only shifted by 10 nm around 1550 nm over a pump tuning range of 350 nm. Simulations using two coupled full vectorial nonlinear Schrödinger equations fully support the experimental results.

  2. Synchrotron Environmental Science-I Workshop Report

    International Nuclear Information System (INIS)

    1999-01-01

    Attendees of the Synchrotrons Environmental Science 1 (SES-1) workshop represented a broad spectrum of environmental science research areas and expertise in all of the current synchrotrons techniques (X-ray scattering and diffraction, X-ray absorption spectroscopy, and two- and three-dimensional X-ray imaging). These individuals came together to discuss current measurement obstacles in environmental research and, more specifically, ways to overcome such obstacles by applying synchrotrons radiation techniques. Significant obstacles in measurement affect virtually all of the research issues described. Attendees identified synchrotrons approaches of potential value in their research. A number of the environmental research studies discussed are currently being addressed with some success by synchrotron-based approaches. Nevertheless, improvements in low-Z measurement capabilities are needed to facilitate the use of synchrotrons radiation methodologies in environmental research

  3. Synchrotron Environmental Science-I Workshop Report.

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-07-08

    Attendees of the Synchrotrons Environmental Science 1 (SES-1) workshop represented a broad spectrum of environmental science research areas and expertise in all of the current synchrotrons techniques (X-ray scattering and diffraction, X-ray absorption spectroscopy, and two- and three-dimensional X-ray imaging). These individuals came together to discuss current measurement obstacles in environmental research and, more specifically, ways to overcome such obstacles by applying synchrotrons radiation techniques. Significant obstacles in measurement affect virtually all of the research issues described. Attendees identified synchrotrons approaches of potential value in their research. A number of the environmental research studies discussed are currently being addressed with some success by synchrotron-based approaches. Nevertheless, improvements in low-Z measurement capabilities are needed to facilitate the use of synchrotrons radiation methodologies in environmental research.

  4. THE STRUCTURE AND LINEAR POLARIZATION OF THE KILOPARSEC-SCALE JET OF THE QUASAR 3C 345

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, David H.; Wardle, John F. C.; Marchenko, Valerie V., E-mail: roberts@brandeis.edu [Department of Physics MS-057, Brandeis University, Waltham, MA 02454-0911 (United States)

    2013-02-01

    Deep Very Large Array imaging of the quasar 3C 345 at 4.86 and 8.44 GHz has been used to study the structure and linear polarization of its radio jet on scales ranging from 2 to 30 kpc. There is a 7-8 Jy unresolved core with spectral index {alpha} {approx_equal} -0.24 (I{sub {nu}}{proportional_to}{nu}{sup {alpha}}). The jet (typical intensity 15 mJy beam{sup -1}) consists of a 2.''5 straight section containing two knots, and two additional non-co-linear knots at the end. The jet's total projected length is about 27 kpc. The spectral index of the jet varies over -1.1 {approx}< {alpha} {approx}< -0.5. The jet diverges with a semi-opening angle of about 9 Degree-Sign , and is nearly constant in integrated brightness over its length. A faint feature northeast of the core does not appear to be a true counter-jet, but rather an extended lobe of this FR-II radio source seen in projection. The absence of a counter-jet is sufficient to place modest constraints on the speed of the jet on these scales, requiring {beta} {approx}> 0.5. Despite the indication of jet precession in the total intensity structure, the polarization images suggest instead a jet re-directed at least twice by collisions with the external medium. Surprisingly, the electric vector position angles in the main body of the jet are neither longitudinal nor transverse, but make an angle of about 55 Degree-Sign with the jet axis in the middle while along the edges the vectors are transverse, suggesting a helical magnetic field. There is no significant Faraday rotation in the source, so that is not the cause of the twist. The fractional polarization in the jet averages 25% and is higher at the edges. In a companion paper, Roberts and Wardle show that differential Doppler boosting in a diverging relativistic velocity field can explain the electric vector pattern in the jet.

  5. A polarized atomic-beam target for COSY-Juelich

    International Nuclear Information System (INIS)

    Eversheim, P. D.; Altmeier, M.; Felden, O.; Glende, M.; Walker, M.; Hiemer, A.; Gebel, R.

    1998-01-01

    An atomic-beam target (ABT) for the EDDA experiment has been built in Bonn and was tested for the very first time at the cooler synchrotron COSY. The ABT differs from the polarized colliding-beams ion source for COSY in the DC-operation of the dissociator and the use of permanent 6-pole magnets. At present the beam optics of the ABT is set-up for maximum density in the interaction zone, but for target-cell operation it can be modified to give maximum intensity. The modular concept of this atomic ground-state target allows to provide all vector- (and tensor) polarizations for protons and deuterons, respectively. Up to now the polarization of the atomic-beam could be verified by the EDDA experiment to be > or approx. 80% with a density in the interaction zone of > or approx. 10 11 atoms/cm 2

  6. Polarized beams in high energy storage rings

    Energy Technology Data Exchange (ETDEWEB)

    Montague, B W [European Organization for Nuclear Research, Geneva (Switzerland)

    1984-11-01

    In recent years there has been a considerable advance in understanding the spin motion of particles in storage rings and accelerators. The survey presented here outlines the early historical development in this field, describes the basic ideas governing the kinetics of polarized particles in electromagnetic fields and shows how these have evolved into the current description of polarized beam behaviour. Orbital motion of particles influences their spin precession, and depolarization of a beam can result from excitation of spin resonances by orbit errors and oscillations. Electrons and positrons are additionally influenced by the quantized character of synchrotron radiation, which not only provides a polarizing mechanism but also enhances depolarizing effects. Progress in the theoretical formulation of these phenomena has clarified the details of the physical processes and suggested improved methods of compensating spin resonances. Full use of polarized beams for high-energy physics with storage rings requires spin rotators to produce longitudinal polarization in the interaction regions. Variants of these schemes, dubbed Siberian snakes, provide a curious precession topology which can substantially reduce depolarization in the high-energy range. Efficient polarimetry is an essential requirement for implementing polarized beams, whose utility for physics can be enhanced by various methods of spin manipulation.

  7. Multiple-band reflective polarization converter using U-shaped metamaterial

    International Nuclear Information System (INIS)

    Huang, Xiaojun; Yang, Dong; Yang, Helin

    2014-01-01

    A multiple-band metamaterial reflective polarization converter (RPC) is proposed, which is composed of the dielectric substrate sandwiched with U-shaped metallic patterns and continuous metal film. The proposed U-shaped metamaterial RPC (UMM-RPC) can convert a linearly polarized wave to its cross polarized wave at the three resonant frequencies, which also can convert the linearly polarized wave to circularly polarized wave at other three resonant frequencies. Furthermore, the proposed UMM-RPC can maintain the same conversional direction at the three resonant frequencies when incident on a circularly polarized wave. The simulated and measured results are in agreement in the entire frequency range, and the polarization conversion ratio is over 90% for both linear and circular polarizations. The surface current distributions of the UMM-RPC are discussed to look into the physical mechanism. The proposed UMM-RPC has simple geometry but more operating frequency bands compared to the previous designs and can be used in applications such as antenna radome, remote sensors, and radiometer

  8. Multiple-band reflective polarization converter using U-shaped metamaterial

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xiaojun [College of Physical Science and Technology, Central China Normal University, Wuhan 430079 (China); Department of Physics, Kashgar Teachers College, Kashgar 844000 (China); Yang, Dong [College of Physics and Electronics Science, Hubei Normal University, Huangshi 435002 (China); Yang, Helin, E-mail: emyang@mail.ccnu.edu.cn [College of Physical Science and Technology, Central China Normal University, Wuhan 430079 (China)

    2014-03-14

    A multiple-band metamaterial reflective polarization converter (RPC) is proposed, which is composed of the dielectric substrate sandwiched with U-shaped metallic patterns and continuous metal film. The proposed U-shaped metamaterial RPC (UMM-RPC) can convert a linearly polarized wave to its cross polarized wave at the three resonant frequencies, which also can convert the linearly polarized wave to circularly polarized wave at other three resonant frequencies. Furthermore, the proposed UMM-RPC can maintain the same conversional direction at the three resonant frequencies when incident on a circularly polarized wave. The simulated and measured results are in agreement in the entire frequency range, and the polarization conversion ratio is over 90% for both linear and circular polarizations. The surface current distributions of the UMM-RPC are discussed to look into the physical mechanism. The proposed UMM-RPC has simple geometry but more operating frequency bands compared to the previous designs and can be used in applications such as antenna radome, remote sensors, and radiometer.

  9. Optimization of AGS Polarized Proton Operation with the Warm Helical Snake

    CERN Document Server

    Takano, Junpei; Bai, Mei; Brown, Kevin A; Gardner, Chris J; Glenn, Joseph; Hattori, Toshiyuki; Huang, Haixin; Luccio, Alfredo U; MacKay, William W; Okamura, Masahiro; Roser, Thomas; Tepikian, Steven; Tsoupas, Nicholaos

    2005-01-01

    A normal conducting helical dipole partial Siberian snake (Warm Snake) has been installed in the Alternating Gradient Synchrotron (AGS) at Brookhaven National Laboratory (BNL) for overcoming all of imperfection depolarizing resonances and reducing the transverse coupling resonances caused by the solenoidal Siberian snake which had been operated in AGS before the last polarized run. The polarized proton beam has been accelerated successfully with the warm snake and the polarization at extraction of the AGS was increased to 50% as opposed to 40% with the solenoidal snake. The magnetic field and beam trajectory in the warm snake was calculated by using the OPERA-3D/TOSCA software. We present optimization of the warm snake with beam during RUN5.

  10. 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

  11. Electron cooling system in the booster synchrotron of the HIAF project

    Energy Technology Data Exchange (ETDEWEB)

    Mao, L.J., E-mail: maolijun@impcas.ac.cn [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Yang, J.C.; Xia, J.W.; Yang, X.D.; Yuan, Y.J.; Li, J.; Ma, X.M.; Yan, T.L.; Yin, D.Y.; Chai, W.P.; Sheng, L.N. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Shen, G.D.; Zhao, H.; Tang, M.T. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China)

    2015-06-21

    The High Intensity heavy ion Accelerator Facility (HIAF) is a new accelerator complex under design at the Institute of Modern Physics (IMP). The facility is aiming at the production of high intensity heavy ion beams for a wide range of experiments in high energy density physics, nuclear physics, atomic physics and other applications. It consists of a superconducting electron-cyclotron-resonance ion source and an intense proton ion source, a linear accelerator, a 34 Tm booster synchrotron ring, a 43 Tm multifunction compression synchrotron ring, a 13 Tm high precision spectrometer ring and several experimental terminals. A magnetized electron cooling device is supposed to be used in the booster ring for decreasing the transverse emittance of injected beams. The conceptual design and main parameters of this cooler are presented in this paper.

  12. Study of coherent Synchrotron Radiation effects by means of a new simulation code based on the non-linear extension of the operator splitting method

    International Nuclear Information System (INIS)

    Dattoli, G.; Schiavi, A.; Migliorati, M.

    2006-03-01

    The coherent synchrotron radiation (CSR) is one of the main problems limiting the performance of high intensity electron accelerators. The complexity of the physical mechanisms underlying the onset of instabilities due to CSR demands for accurate descriptions, capable of including the large number of features of an actual accelerating device. A code devoted to the analysis of this type of problems should be fast and reliable, conditions that are usually hardly achieved at the same rime. In the past, codes based on Lie algebraic techniques , have been very efficient to treat transport problems in accelerators. The extension of these methods to the non-linear case is ideally suited to treat CSR instability problems. We report on the development of a numerical code, based on the solution of the Vlasov equation, with the inclusion of non-linear contribution due to wake field effects. The proposed solution method exploits an algebraic technique, using exponential operators. We show that the integration procedure is capable of reproducing the onset of an instability and the effects associated with bunching mechanisms leading to the growth of the instability itself. In addition, considerations on the threshold of the instability are also developed [it

  13. Study of coherent synchrotron radiation effects by means of a new simulation code based on the non-linear extension of the operator splitting method

    International Nuclear Information System (INIS)

    Dattoli, G.; Migliorati, M.; Schiavi, A.

    2007-01-01

    The coherent synchrotron radiation (CSR) is one of the main problems limiting the performance of high-intensity electron accelerators. The complexity of the physical mechanisms underlying the onset of instabilities due to CSR demands for accurate descriptions, capable of including the large number of features of an actual accelerating device. A code devoted to the analysis of these types of problems should be fast and reliable, conditions that are usually hardly achieved at the same time. In the past, codes based on Lie algebraic techniques have been very efficient to treat transport problems in accelerators. The extension of these methods to the non-linear case is ideally suited to treat CSR instability problems. We report on the development of a numerical code, based on the solution of the Vlasov equation, with the inclusion of non-linear contribution due to wake field effects. The proposed solution method exploits an algebraic technique that uses the exponential operators. We show that the integration procedure is capable of reproducing the onset of instability and the effects associated with bunching mechanisms leading to the growth of the instability itself. In addition, considerations on the threshold of the instability are also developed

  14. Coherent Synchrotron Radiation effect in damping rings

    International Nuclear Information System (INIS)

    Raubenheimer, T

    2004-01-01

    Coherent Synchrotron Radiation (CSR) can play an important role by not only increasing the energy spread and emittance of a beam, but also leading to a potential instability. Previous studies of the CSR induced longitudinal instability were carried out for the CSR impedance due to dipole magnets. In this paper, the instability due to the CSR impedance from a wiggler is studied assuming a large wiggler parameter K. The primary consideration is a low frequency microwave-like instability in the damping rings of several linear collider projects. The threshold is determined by the instability with the longest possible wavelength

  15. Interaction of low-intensity linearly polarized laser radiation with living tissues: effects on tissular acceleration of skin wound healing; Interacao da radiacao laser linearmente polarizada de baixa intensidade com tecidos vivos: efeitos na acelaracao de cicatrizacao tissular em lesoes de pele

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Martha Simoes

    2000-07-01

    According to the Maxwell's equations to optical properties of surfaces, the energy deposition efficiency in a microroughness interface depends on the electrical field polarization component. Considering a linearly polarized beam, this efficiency will depend on the roughness parameters to p-polarized light and it will not depend on such parameters to s-polarized light. In this work it was investigated the effects of low-intensity, linearly polarized He-Ne laser beam on skin wounds healing, considering two orthogonal directions of polarization. We have considered a preferential axis as the animals' spinal column and we aligned the linear laser polarization first parallel, then perpendicular to this direction. Burns about 6 mm in diameter were created with liquid N{sub 2} on the back of the animals and the lesions were irradiated on days 3, 7, 10 and 14 post-wounding, D= 1,0 J/cm{sup 2}. Control lesions were not irradiated. The theoretical model consisted in describing linearly polarized light propagation in biological tissues using transport theory. The degree of polarization was measured in normal and pathological skin samples. It was verified that linearly polarized light can survive in the superficial layers of skin and it can be more preserved in skin under pathological condition when compared with health skin. The analysis of skin wound healing process has demonstrated that the relative direction of the laser polarization plays an important role on the wound healing process by light microscopy, transmission electron microscopy and radioautography. (author)

  16. 15 W high OSNR kHz-linewidth linearly-polarized all-fiber single-frequency MOPA at 1.6 μm.

    Science.gov (United States)

    Yang, Changsheng; Guan, Xianchao; Zhao, Qilai; Lin, Wei; Li, Can; Gan, Jiulin; Qian, Qi; Feng, Zhouming; Yang, Zhongmin; Xu, Shanhui

    2018-05-14

    A 1603 nm high optical signal-to-noise ratio (OSNR) kHz-linewidth linearly-polarized all-fiber single-frequency master-oscillator power amplifier (MOPA) is demonstrated. To suppress the amplified spontaneous emission from Yb 3+ /Er 3+ ions with the customized filters and optimize the length of the double cladding active fiber, an over 15 W stable single-longitudinal-mode laser is achieved with an OSNR of >70 dB. A measured laser linewidth of 4.5 kHz and a polarization-extinction ratio of >23 dB are obtained at the full output power. This L-band high-power single-frequency MOPA is promising for high-resolution molecular spectroscopy and pumping of Tm 3+ -doped or Tm 3+ /Ho 3+ co-doped laser.

  17. New method for preparing a liquid crystal polymer that exhibits linearly polarized white fluorescence

    International Nuclear Information System (INIS)

    Zheng Shijun; Kun, Wang; Kobayashi, Takaomi

    2011-01-01

    With the aim of developing a single-chain white-light-emitting polymer, liquid crystal (LC) polymers with a shish-kebab-type moiety on their cross-conjugated (p-phenylene)s-poly(p-phenylenevinylene)s main chain were synthesized by Gilch polymerization. They were characterized by nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and polarizing optical microscopy (POM). 1 H-NMR indicated that the polymers had a shish-kebab structure, which strongly suppressed the formation of structural defects in the polymers. DSC revealed that the polymers had thermotropic LC properties, indicating that the LC polymers were enantiotropic. XRD showed that the polymers had a mesophase, which implies that they were in a smectic LC phase. A polymer with 'kebabs' of 2,5-bis(4'-alkoxyphenyl)benzene was combined with an aligned polyimide film with orientated microgrooves. The polymer main chain was aligned due to the orientation of the 'kebabs' of the uniform cross-conjugated structure. It lay between the kebabs and the 'shish' of the polymer main chains. The aligned polymer main chain emitted yellow light while and the oriented LC side chains emitted blue light emission. These two emissions resulted in linearly polarized white fluorescence.

  18. A Monte-Carlo simulation of the equilibrium beam polarization in ultra-high energy electron (positron) storage rings

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Zhe, E-mail: zhe.duan@ihep.ac.cn [Key Laboratory of Particle Acceleration Physics and Technology, Institute of High Energy Physics, Chinese Academy of Sciences, 100049 Beijing (China); University of Chinese Academy of Sciences, 100049 Beijing (China); Bai, Mei [Forschungszentrum Jülich GmbH, 52428 Jülich (Germany); Barber, Desmond P. [Deutsches Elektronen-Synchrotron, DESY, 22607 Hamburg (Germany); Qin, Qing [Key Laboratory of Particle Acceleration Physics and Technology, Institute of High Energy Physics, Chinese Academy of Sciences, 100049 Beijing (China)

    2015-09-01

    With the recently emerging global interest in building a next generation of circular electron–positron colliders to study the properties of the Higgs boson, and other important topics in particle physics at ultra-high beam energies, it is also important to pursue the possibility of implementing polarized beams at this energy scale. It is therefore necessary to set up simulation tools to evaluate the beam polarization at these ultra-high beam energies. In this paper, a Monte-Carlo simulation of the equilibrium beam polarization based on the Polymorphic Tracking Code (PTC) (Schmidt et al., 2002 [1]) is described. The simulations are for a model storage ring with parameters similar to those of proposed circular colliders in this energy range, and they are compared with the suggestion (Derbenev et al., 1979 [2]) that there are different regimes for the spin dynamics underlying the polarization of a beam in the presence of synchrotron radiation at ultra-high beam energies. In particular, it has been suggested that the so-called “correlated” crossing of spin resonances during synchrotron oscillations at current energies evolves into “uncorrelated” crossing of spin resonances at ultra-high energies.

  19. A Monte-Carlo simulation of the equilibrium beam polarization in ultra-high energy electron (positron) storage rings

    International Nuclear Information System (INIS)

    Duan, Zhe; Bai, Mei; Barber, Desmond P.; Qin, Qing

    2015-04-01

    With the recently emerging global interest in building a next generation of circular electron-positron colliders to study the properties of the Higgs boson, and other important topics in particle physics at ultra-high beam energies, it is also important to pursue the possibility of implementing polarized beams at this energy scale. It is therefore necessary to set up simulation tools to evaluate the beam polarization at these ultra-high beam energies. In this paper, a Monte-Carlo simulation of the equilibrium beam polarization based on the Polymorphic Tracking Code(PTC) (Schmidt et al., 2002) is described. The simulations are for a model storage ring with parameters similar to those of proposed circular colliders in this energy range, and they are compared with the suggestion (Derbenev et al., 1978) that there are different regimes for the spin dynamics underlying the polarization of a beam in the presence of synchrotron radiation at ultra-high beam energies. In particular, it has been suggested that the so-called ''correlated'' crossing of spin resonances during synchrotron oscillations at current energies, evolves into ''uncorrelated'' crossing of spin resonances at ultra-high energies.

  20. CORNELL: Synchrotron 25

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    A recent celebration marked the twenty-fifth anniversary of the Cornell Electron Synchrotron. The major milestone in the commissioning of the synchrotron was on October 11, 1967 when Helen Edwards, Boyce McDaniel, and Maury Tigner achieved a 7 GeV beam, a worldrecord energy for electron synchrotrons at that time. Like so many advances in experimental physics, this occurred early in the morning - 3 a.m.! The transition from accelerator commissioning to high energy physics operation was extremely rapid; 7 GeV operation for data collection was routine just five weeks later. Throughout its life as a source of photon and electron beams for fixed target experiments, the synchrotron maintained energy leadership for circular electron machines. Originally designed for operation at 10 GeV, eventually it consistently provided beams for experiments at energies up to 11.6 GeV. It now operates at 5 GeV, serving as the injector for the CESR electron-positron storage ring. Robert Wilson was director of the laboratory during the design and most of the construction of the machine. He left near the end of the construction to become the first director of Fermilab and was replaced by Boyce McDaniel, who guided the laboratory from the completion of the synchrotron to the construction and early operation of CESR. Wilson recalled how the laboratory had originally proposed a 3 GeV turnkey machine to be built entirely by industry and would fit in the space previously occupied by earlier Cornell accelerators. However, members of the laboratory realized that 3 GeV would not open new physics frontiers, that the construction of the accelerator was much of the fun of doing high energy physics experiments, and that a more challenging project was needed. This led to the proposal for the 10 GeV synchrotron which was built in the ''Cornell Style'' with many of the components fabricated and nearly all of the assembly done at Cornell

  1. CORNELL: Synchrotron 25

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1993-03-15

    A recent celebration marked the twenty-fifth anniversary of the Cornell Electron Synchrotron. The major milestone in the commissioning of the synchrotron was on October 11, 1967 when Helen Edwards, Boyce McDaniel, and Maury Tigner achieved a 7 GeV beam, a worldrecord energy for electron synchrotrons at that time. Like so many advances in experimental physics, this occurred early in the morning - 3 a.m.! The transition from accelerator commissioning to high energy physics operation was extremely rapid; 7 GeV operation for data collection was routine just five weeks later. Throughout its life as a source of photon and electron beams for fixed target experiments, the synchrotron maintained energy leadership for circular electron machines. Originally designed for operation at 10 GeV, eventually it consistently provided beams for experiments at energies up to 11.6 GeV. It now operates at 5 GeV, serving as the injector for the CESR electron-positron storage ring. Robert Wilson was director of the laboratory during the design and most of the construction of the machine. He left near the end of the construction to become the first director of Fermilab and was replaced by Boyce McDaniel, who guided the laboratory from the completion of the synchrotron to the construction and early operation of CESR. Wilson recalled how the laboratory had originally proposed a 3 GeV turnkey machine to be built entirely by industry and would fit in the space previously occupied by earlier Cornell accelerators. However, members of the laboratory realized that 3 GeV would not open new physics frontiers, that the construction of the accelerator was much of the fun of doing high energy physics experiments, and that a more challenging project was needed. This led to the proposal for the 10 GeV synchrotron which was built in the ''Cornell Style'' with many of the components fabricated and nearly all of the assembly done at Cornell.

  2. Applications of circularly polarized photons at the ALS with a bend magnet source

    International Nuclear Information System (INIS)

    1992-02-01

    The purpose of this workshop is to focus attention on, and to stimulate the scientific exploitation of, the natural polarization properties of bend-magnet synchrotron radiation at the ALS -- for research in biology, materials science, physics, and chemistry. The topics include: The Advanced Light Source; Magnetic Circular Dichroism and Differential Scattering on Biomolecules; Tests of Fundamental Symmetries; High T c Superconductivity; Photoemission from Magnetic and Non-magnetic Solids; Studies of Highly Correlated Systems; and Instrumentation for Photon Transport and Polarization Measurements

  3. Recovering a hidden polarization by ghost polarimetry.

    Science.gov (United States)

    Janassek, Patrick; Blumenstein, Sébastien; Elsäßer, Wolfgang

    2018-02-15

    By exploiting polarization correlations of light from a broadband fiber-based amplified spontaneous emission source we succeed in reconstructing a hidden polarization in a ghost polarimetry experiment in close analogy to ghost imaging and ghost spectroscopy. Thereby, an original linear polarization state in the object arm of a Mach-Zehnder interferometer configuration which has been camouflaged by a subsequent depolarizer is recovered by correlating it with light from a reference beam. The variation of a linear polarizer placed inside the reference beam results in a Malus law type second-order intensity correlation with high contrast, thus measuring a ghost polarigram.

  4. The World of Synchrotrons

    Indian Academy of Sciences (India)

    de Ciencias Fisicas,. Universidad Nacional. Autonoma de Mexico. Sameen Ahmed Khan. A summary of results on synchrotron radiation is presented along with notes on its properties and applications. Quantum aspects are briefly mentioned. Synchrotron radiation facilities are described briefly with a detailed coverage of ...

  5. Detecting Changing Polarization Structures in Sagittarius A* with High Frequency VLBI

    Science.gov (United States)

    Fish, Vincent L.; Doeleman, Sheperd S.; Broderick, Avery E.; Loeb, Abraham; Rogers, Alan E. E.

    2009-12-01

    Sagittarius A* is the source of near infrared, X-ray, radio, and (sub)millimeter emission associated with the supermassive black hole at the Galactic Center. In the submillimeter regime, Sgr A* exhibits time-variable linear polarization on timescales corresponding to errors. Although the source-integrated linear polarization fraction in the models is typically only a few percent, the linear polarization fraction on small angular scales can be much higher, enabling the detection of changes in the polarimetric structure of Sgr A* on a wide variety of baselines. The shortest baselines track the source-integrated linear polarization fraction, while longer baselines are sensitive to polarization substructures that are beam-diluted by connected-element interferometry. The detection of periodic variability in source polarization should not be significantly affected even if instrumental polarization terms cannot be calibrated out. As more antennas are included in the (sub)millimeter-VLBI array, observations with full polarization will provide important new diagnostics to help disentangle intrinsic source polarization from Faraday rotation effects in the accretion and outflow region close to the black hole event horizon.

  6. Ultraviolet interstellar linear polarization. I - Applicability of current dust grain models

    Science.gov (United States)

    Wolff, Michael J.; Clayton, Geoffrey C.; Meade, Marilyn R.

    1993-01-01

    UV spectropolarimetric observations yielding data on the wavelength-dependence of interstellar polarization along eight lines of sight facilitate the evaluation of dust grain models previously used to fit the extinction and polarization in the visible and IR. These models pertain to bare silicate/graphite grains, silicate cores with organic refractory mantles, silicate cores with amorphous carbon mantles, and composite grains. The eight lines-of-sight show three different interstellar polarization dependences.

  7. Synchrotron light source data book

    International Nuclear Information System (INIS)

    Murphy, J.

    1989-01-01

    The ''Synchrotron Light Source Data Book'' is as its name implies a collection of data on existing and planned synchrotron light sources. The intention was to provide a compendium of tools for the design of electron storage rings as synchrotron radiation sources. The slant is toward the accelerator physicist as other booklets such as the X-ray Data Booklet, edited by D. Vaughan (LBL PUB-490), address the 'use' of synchrotron radiation. It is hoped that the booklet serves as a pocket sized reference to facilitate back of the envelope type calculations. It contains some useful formulae in 'practical units' and a brief description of many of the existing and planned light source lattices

  8. JHF synchrotrons

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    The Japan Hadron Facility (JHF) consists of two synchrotrons and an injector linac. First, we will present a brief review of the specifications and lattice of the synchrotrons; one is 3 GeV booster and the other is 50 GeV main ring. Secondly, some detailed results of design study will be discussed, together with the present status of the R and D programs in progress. Among them, an estimate of beam loss is one of critical issues in beam dynamics. The development of a high gradient RF cavity is also crucial for a high intensity machine. (author)

  9. The polarized atomic-beam target for the EDDA experiment and the time-reversal invariance test at COSY

    International Nuclear Information System (INIS)

    Eversheim, P.D.; Altmeier, M.; Felden, O.

    1996-01-01

    For the the EDDA experiment, which was set up to measure the p-vector - p-vector excitation function during the acceleration ramp of the cooler synchrotron COSY at Juelich, a polarized atomic-beam target was designed regarding the restrictions imposed by the geometry of the EDDA detector. Later, when the time-reversal invariance experiment is to be performed, the EDDA detector will serve as efficient internal polarimeter and the source has to deliver tensor polarized deuterons. The modular design of this polarized atomic-beam target that allows to meet these conditions are discussed in comparison to other existing polarized atomic-beam targets. (orig.)

  10. Infrared spectroscopy by use of synchrotron radiation

    International Nuclear Information System (INIS)

    Nanba, Takao

    1991-01-01

    During five years since the author wrote the paper on the utilization of synchrotron radiation in long wavelength region, it seems to be recognized that in synchrotron radiation, the light from infrared to milli wave can be utilized, and is considerably useful. Recently the research on coherent synchrotron radiation in this region using electron linac has been developed by Tohoku University group, and the high capability of synchrotron radiation as light source is verified. This paper is the report on the infrared spectroscopic research using incoherent synchrotron radiation obtained from the deflection electromagnet part of electron storage rings. Synchrotron radiation is high luminance white light source including from X-ray to micro wave. The example of research that the author carried out at UVSOR is reported, and the perspective in near future is mentioned. Synchrotron radiation as the light source for infrared spectroscopy, the intensity and dimensions of the light source, far infrared region and mid infrared region, far infrared high pressure spectroscopic experiment, and the heightening of luminance of synchrotron radiation as infrared light source are described. (K.I.)

  11. Efficiency of respiratory-gated delivery of synchrotron-based pulsed proton irradiation

    International Nuclear Information System (INIS)

    Tsunashima, Yoshikazu; Vedam, Sastry; Dong, Lei; Bues, Martin; Balter, Peter; Smith, Alfred; Mohan, Radhe; Umezawa, Masumi; Sakae, Takeji

    2008-01-01

    Significant differences exist in respiratory-gated proton beam delivery with a synchrotron-based accelerator system when compared to photon therapy with a conventional linear accelerator. Delivery of protons with a synchrotron accelerator is governed by a magnet excitation cycle pattern. Optimal synchronization of the magnet excitation cycle pattern with the respiratory motion pattern is critical to the efficiency of respiratory-gated proton delivery. There has been little systematic analysis to optimize the accelerator's operational parameters to improve gated treatment efficiency. The goal of this study was to estimate the overall efficiency of respiratory-gated synchrotron-based proton irradiation through realistic simulation. Using 62 respiratory motion traces from 38 patients, we simulated respiratory gating for duty cycles of 30%, 20% and 10% around peak exhalation for various fixed and variable magnet excitation patterns. In each case, the time required to deliver 100 monitor units in both non-gated and gated irradiation scenarios was determined. Based on results from this study, the minimum time required to deliver 100 MU was 1.1 min for non-gated irradiation. For respiratory-gated delivery at a 30% duty cycle around peak exhalation, corresponding average delivery times were typically three times longer with a fixed magnet excitation cycle pattern. However, when a variable excitation cycle was allowed in synchrony with the patient's respiratory cycle, the treatment time only doubled. Thus, respiratory-gated delivery of synchrotron-based pulsed proton irradiation is feasible and more efficient when a variable magnet excitation cycle pattern is used

  12. 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)

  13. Controlling periodic ripple microstructure formation on 4H-SiC crystal with three time-delayed femtosecond laser beams of different linear polarizations.

    Science.gov (United States)

    He, Wanlin; Yang, Jianjun; Guo, Chunlei

    2017-03-06

    The control of laser-induced periodic ripple microstructures on 4H-SiC crystal surface is studied using temporally delayed collinear three femtosecond laser pulse trains linearly polarized in different directions. The ripple orientation appears to develop independent of the individual laser polarizations and exhibits non-monotonical change with variable time delays, whose variation tendency is also affected by the polarization intersection angles. Remarkably, the ripple period is observed to transfer from high- to low-spatial-frequency regions, accompanied by distinctly improved morphological uniformity and clearness. The results are satisfactorily interpreted based on a physical model of the surface wave excitation on a transient index metasurface, which is confirmed by further experiments. Our investigations indicate that transient noneqilibrium dynamics of the material surface provides an effective way to manipulate the laser-induced microstructures.

  14. In situ analyses of Ag speciation in tissues of cucumber and wheat using synchrotron-based X-ray absorption spectroscopy

    Data.gov (United States)

    U.S. Environmental Protection Agency — In situ analyses of Ag speciation in tissues of cucumber and wheat using synchrotron-based X-ray absorption spectroscopy showing spectral fitting and linear...

  15. Inverse comptonization vs. thermal synchrotron

    International Nuclear Information System (INIS)

    Fenimore, E.E.; Klebesadel, R.W.; Laros, J.G.

    1983-01-01

    There are currently two radiation mechanisms being considered for gamma-ray bursts: thermal synchrotron and inverse comptonization. They are mutually exclusive since thermal synchrotron requires a magnetic field of approx. 10 12 Gauss whereas inverse comptonization cannot produce a monotonic spectrum if the field is larger than 10 11 and is too inefficient relative to thermal synchrotron unless the field is less than 10 9 Gauss. Neither mechanism can explain completely the observed characteristics of gamma-ray bursts. However, we conclude that thermal synchrotron is more consistent with the observations if the sources are approx. 40 kpc away whereas inverse comptonization is more consistent if they are approx. 300 pc away. Unfortunately, the source distance is still not known and, thus, the radiation mechanism is still uncertain

  16. Synchrotron radiation at Trieste

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1986-06-15

    The fast developing field of synchrotron radiation has its origins in the mastery of storage rings in high energy physics and is a prime example of spinoff from pure science. Intense electromagnetic radiation streams off when beams of high energy electrons are bent or shaken. This synchrotron radiation was once an annoying waste of energy in particle storage rings, but now the wheel has turned full circle, with dedicated machines supplying this radiation for a wide range of science. The astonishing growth rate in this field was highlighted at an International Conference on Synchrotron Radiation, held at the International Centre for Theoretical Physics (ICTP), Trieste, Italy from 7-11 April.

  17. Synchrotron radiation at Trieste

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    The fast developing field of synchrotron radiation has its origins in the mastery of storage rings in high energy physics and is a prime example of spinoff from pure science. Intense electromagnetic radiation streams off when beams of high energy electrons are bent or shaken. This synchrotron radiation was once an annoying waste of energy in particle storage rings, but now the wheel has turned full circle, with dedicated machines supplying this radiation for a wide range of science. The astonishing growth rate in this field was highlighted at an International Conference on Synchrotron Radiation, held at the International Centre for Theoretical Physics (ICTP), Trieste, Italy from 7-11 April

  18. Beam-beam interaction in high energy linear electron-positron colliders

    International Nuclear Information System (INIS)

    Ritter, S.

    1985-04-01

    The interaction of high energy electron and positron beams in a linear collider has been investigated using a macroparticle Monte Carlo method based on a Cloud-In-Cells plasma simulation scheme. Density evolutions, luminosities, energy and angular distributions for electrons (positrons) and synchrotron photons are calculated. Beside beams with a symmetric transverse profile also flat beams are considered. A reasonably good agreement to alternative computer calculations as well as to an analytical approximation for the energy spectrum of synchrotron photons has been obtained. (author)

  19. Visualization of polarization state and its application in optics classroom teaching

    Science.gov (United States)

    Lei, Bing; Liu, Wei; Shi, Jianhua; Wang, Wei; Yao, Tianfu; Liu, Shugang

    2017-08-01

    Polarization of light and the related knowledge are key and difficult points in optical teaching, and they are difficult to be understood since they are very abstract concepts. To help students understand the polarization properties of light, some classroom demonstration experiments have been constructed by employing the optical source, polarizers, wave plates optical cage system and polarization axis finder (PAF). The PAF is a polarization indicating device with many linear polarizing components concentric circles, which can visualize the polarization axis's direction of linearly polarized light intuitively. With the help of these demonstration experiment systems, the conversion and difference between the linear polarized light and circularly polarized light have been observed directly by inserting or removing a quarter-wave plate. The rotation phenomenon of linearly polarized light's polarization axis when it propagates through an optical active medium has been observed and studied in experiment, and the strain distribution of some mounted and unmounted lenses have also been demonstrated and observed in experiment conveniently. Furthermore, some typical polarization targets, such as liquid crystal display (LCD), polarized dark glass and skylight, have been observed based on PAF, which is quite suitable to help students understand these targets' polarization properties and the related physical laws. Finally, these demonstration experimental systems have been employed in classroom teaching of our university in physical optics, optoelectronics and photoelectric detection courses, and they are very popular with teachers and students.

  20. Synchrotron Radiation in Biology and Medicine

    International Nuclear Information System (INIS)

    Pelka, J.B.

    2008-01-01

    This work is focused on a present status of synchrotron radiation X-ray applications in medicine and biology to imaging, diagnostics, and radio- therapy. Properties of X-ray beams generated by synchrotron sources are compared with radiation produced by classical laboratory X-ray tubes. A list of operating and planned synchrotron facilities applicable to biomedical purposes is given, together with their basic characteristics. A concise overview of typical X-ray synchrotron techniques in biology and medicine is carried out with discussion of their specific properties and examples of typical results. (author)

  1. Measurement of polarization observables in the reaction γp→ pπ0π0 using linearly polarized photons with the CBELSA/TAPS experiment

    International Nuclear Information System (INIS)

    Sokhoyan, Vahe

    2012-01-01

    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 s , I c and the respective twobody asymmetry Σ were measured for the reaction γp → pπ 0 π 0 in an incoming photon energy range of E γ = 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 s and I c which occur in two-meson final states are measured for the first time in the reaction γp → pπ 0 π 0 . The corresponding two-body asymmetry Σ 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 33 (1700) → Δπ 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 Δ(1232), D 13 (1520), F 15 (1680), f 0 (980) and f 2 (1270) in the according Dalitz plots and invariant mass distributions. The contributions of these states are confirmed by the Bonn-Gatchina PWA. An excellent compatibility with the existing data from the previous CBELSA

  2. Constraining Line-of-sight Confusion in the Corona Using Linearly Polarized Observations of the Infrared FeXIII 1075nm and SiX 1430nm Emission Lines

    Science.gov (United States)

    Dima, G. I.; Kuhn, J. R.; Berdyugina, S.

    2017-12-01

    Measurements of the coronal magnetic field are difficult because of the intrinsically faint emission of coronal plasma and the large spurious background due to the bright solar disk. This work addresses the problem of resolving the confusion of the line-of-sight (LOS) integration through the optically-thin corona being observed. Work on developing new measuring techniques based on single-point inversions using the Hanle effect has already been described (Dima et al. 2016). It is important to develop a technique to assess when the LOS confusion makes comparing models and observations problematic. Using forward integration of synthetic emission through magnetohydrodynamic (MHD) models together with simultaneous linearly polarized observations of the FeXIII 1075nm and SiX 1430nm emission lines allows us to assess LOS confusion. Since the lines are both in the Hanle saturated regime their polarization angles are expected to be aligned as long as the gas is sampling the same magnetic field. If significant contributions to the emission is taking place from different regions along the LOS due to the additive nature of the polarized brightness the measured linear polarization between the two lines will be offset. The size of the resolution element is important for this determination since observing larger coronal regions will confuse the variation along the LOS with that in the plane-of-sky. We also present comparisons between synthetic linearly polarized emission through a global MHD model and observations of the same regions obtained using the 0.5m Scatter-free Observatory for Limb Active Regions and Coronae (SOLARC) telescope located on Haleakala, Maui. This work is being done in preparation for the type of observations that will become possible when the next generation 4m DKIST telescope comes online in 2020.

  3. Optical anisotropy of polyimide and polymethacrylate containing photocrosslinkable chalcone group in the side chain under irradiation of a linearly polarized UV light

    CERN Document Server

    Choi, D H

    2002-01-01

    Photocrosslinkable soluble polyimide and polymethacrylate compound were synthesized for studying the optically induced anisotropy of the thin films. Chalcone group was introduced into the side chain unit of two polymers. We observed a photodimerization behavior between the double bonds in the chalcone group and an optical anisotropy of these materials by irradiation of a linearly polarized UV light (LPL). Optical anisotropy of the thin film was also investigated by using polarized UV absorption spectroscopy.The dynamic property of optical anisotropy in photoreactive polyimide was compared to that in polymethacrylate containing chalcone group in the side chain.

  4. CHESS-the Cornell High Energy Synchrotron Source

    International Nuclear Information System (INIS)

    Batterman, B.W.; Cornell Univ., Ithaca, NY

    1980-01-01

    The Wilson Laboratory at Cornell University has done pioneering work on development of high energy synchrotrons. In the last decade, the 12 GeV synchrotron has been the most energetic electron synchrotron in the world. In 1975 plans were formulated to build a 4-8 GeV storage ring in the same tunnel as the synchrotron and to use the latter as the injector for the storage ring. This small radius (the normal bend magnets have R = 87 m), coupled with the relatively high electron energy of the storage ring, makes these magnets potent sources of synchrotron radiation. In June of 1978 the National Science Foundation funded a project to create CHESS, the Cornell High Energy Synchrotron Source. (orig./FKS)

  5. Australian synchrotron radiation science

    International Nuclear Information System (INIS)

    White, J.W.

    1996-01-01

    Full text: The Australian Synchrotron Radiation Program, ASRP, has been set up as a major national research facility to provide facilities for scientists and technologists in physics, chemistry, biology and materials science who need access to synchrotron radiation. Australia has a strong tradition in crystallography and structure determination covering small molecule crystallography, biological and protein crystallography, diffraction science and materials science and several strong groups are working in x-ray optics, soft x-ray and vacuum ultra-violet physics. A number of groups whose primary interest is in the structure and dynamics of surfaces, catalysts, polymer and surfactant science and colloid science are hoping to use scattering methods and, if experience in Europe, Japan and USA can be taken as a guide, many of these groups will need third generation synchrotron access. To provide for this growing community, the Australian National Beamline at the Photon Factory, Tsukuba, Japan, has been established since 1990 through a generous collaboration with Japanese colleagues, the beamline equipment being largely produced in Australia. This will be supplemented in 1997 with access to the world's most powerful synchrotron x-ray source at the Advanced Photon Source, Argonne National Laboratory, USA. Some recent experiments in surface science using neutrons as well as x-rays from the Australian National Beamline will be used to illustrate one of the challenges that synchrotron x-rays may meet

  6. High-energy polarized proton beams a modern view

    CERN Document Server

    Hoffstaetter, Georg Heinz

    2006-01-01

    This monograph begins with a review of the basic equations of spin motion in particle accelerators. It then reviews how polarized protons can be accelerated to several tens of GeV using as examples the preaccelerators of HERA, a 6.3 km long cyclic accelerator at DESY / Hamburg. Such techniques have already been used at the AGS of BNL / New York, to accelerate polarized protons to 25 GeV. But for acceleration to energies of several hundred GeV as in RHIC, TEVATRON, HERA, LHC, or a VLHC, new problems can occur which can lead to a significantly diminished beam polarization. For these high energies, it is necessary to look in more detail at the spin motion, and for that the invariant spin field has proved to be a useful tool. This is already widely used for the description of high-energy electron beams that become polarized by the emission of spin-flip synchrotron radiation. It is shown that this field gives rise to an adiabatic invariant of spin-orbit motion and that it defines the maximum time average polarizat...

  7. Manufacturability of compact synchrotron mirrors

    Science.gov (United States)

    Douglas, Gary M.

    1997-11-01

    While many of the government funded research communities over the years have put their faith and money into increasingly larger synchrotrons, such as Spring8 in Japan, and the APS in the United States, a viable market appears to exist for smaller scale, research and commercial grade, compact synchrotrons. These smaller, and less expensive machines, provide the research and industrial communities with synchrotron radiation beamline access at a portion of the cost of their larger and more powerful counterparts. A compact synchrotron, such as the Aurora-2D, designed and built by Sumitomo Heavy Industries, Ltd. of japan (SHI), is a small footprint synchrotron capable of sustaining 20 beamlines. Coupled with a Microtron injector, with 150 MeV of injection energy, an entire facility fits within a 27 meter [88.5 ft] square floorplan. The system, controlled by 2 personal computers, is capable of producing 700 MeV electron energy and 300 mA stored current. Recently, an Aurora-2D synchrotron was purchased from SHI by the University of Hiroshima. The Rocketdyne Albuquerque Operations Beamline Optics Group was approached by SHI with a request to supply a group of 16 beamline mirrors for this machine. These mirrors were sufficient to supply 3 beamlines for the Hiroshima machine. This paper will address engineering issues which arose during the design and manufacturing of these mirrors.

  8. Radiation self-polarization of electrons moving in a magnetic field. [Vector spin operator, relaxation time

    Energy Technology Data Exchange (ETDEWEB)

    Bagrov, V G; Dorofeev, O F; Sokolov, A A; Ternov, I M; Khalilov, V R [Moskovskij Gosudarstvennyj Univ. (USSR)

    1975-03-11

    When electrons move in a magnetic field, synchrotron radiation gives rise to transitions accompanied by the electron spin reorientation. In this case, it is essential that the transition probability depends on the spin orientation; as a result electron polarization takes place with the spin orientation being predominantly opposite to the direction of the magnetic field. This effect has been called ''radiative self-polarization of electrons''. The present work is concerned with the question how the choice of the spin operator will affect the self-polarization degree and relaxation time. The problem has been solved for a vector spin operator.

  9. Investigation of resonant polarization radiation of relativistic electrons in gratings at small angles

    International Nuclear Information System (INIS)

    Aleinik, A.N.; Chefonov, O.V.; Kalinin, B.N.; Naumenko, G.A.; Potylitsyn, A.P.; Saruev, G.A.; Sharafutdinov, A.F.

    2003-01-01

    The resonant optical polarization radiation (ROPR) in the Smith-Purcell geometry and the one from the inclined grating at the Tomsk synchrotron and 6-MeV microtron have been investigated. The polarization radiation was observed at 4.2 deg. from the 200 MeV electron beam and at 5 deg. from the 6.2 MeV electron beam. Two methods of measurement of ROPR maxima in these two cases have been used. In the first case (the experiment on synchrotron) we have fixed the wavelength of radiation using an optical filter; the orientation dependence of this radiation was measured. In this dependence we have observed two peaks of radiation from electrons in gold foil grating of 0.1 mm period. The first large peak is a zeroth order peak in direction of specular reflection, and the second one is the first-order peak of resonant polarization radiation. In the experiment on microtron the spectra of ROPR from aluminum foil strip grating of 0.2 mm period in the Smith-Purcell geometry were measured, and the peak of the first-order Smith-Purcell radiation in these spectra was observed. The comparison of data obtained with the simulation results has been performed

  10. Synchrotron X-Ray Footprinting on Tour

    OpenAIRE

    Bohon, Jen; Ralston, Corie; D'Mello, Rhijuta; Gupta, Sayan; Chance, Mark R.

    2014-01-01

    Synchrotron X-ray footprinting resources were investigated at a variety of beamlines and synchrotron facilities to understand their potential for a mobile general user. Results indicate that viable resources exist at each synchrotron investigated such that a prospective user need only provide a simple flow apparatus and sample handling accessories to perform this technique.

  11. Elliptical quantum dots as on-demand single photons sources with deterministic polarization states

    Energy Technology Data Exchange (ETDEWEB)

    Teng, Chu-Hsiang; Demory, Brandon; Ku, Pei-Cheng, E-mail: peicheng@umich.edu [Department of Electrical Engineering and Computer Science, University of Michigan, 1301 Beal Ave., Ann Arbor, Michigan 48105 (United States); Zhang, Lei; Hill, Tyler A.; Deng, Hui [Department of Mechanical Engineering, University of Michigan, 2350 Hayward St., Ann Arbor, Michigan 48105 (United States)

    2015-11-09

    In quantum information, control of the single photon's polarization is essential. Here, we demonstrate single photon generation in a pre-programmed and deterministic polarization state, on a chip-scale platform, utilizing site-controlled elliptical quantum dots (QDs) synthesized by a top-down approach. The polarization from the QD emission is found to be linear with a high degree of linear polarization and parallel to the long axis of the ellipse. Single photon emission with orthogonal polarizations is achieved, and the dependence of the degree of linear polarization on the QD geometry is analyzed.

  12. Towards Establishing of National Centre of Synchrotron Radiation in Poland

    International Nuclear Information System (INIS)

    Kolodziej, J.J.; Szymonski, M.

    2004-01-01

    group has asked Polish users of SR to submit a brief description of proposed research projects to be realized at the new facility. In our presentation a review of research proposals currently proposed by Polish scientists will be presented with the aim to determine a set of technical requirements necessary for future synchrotron light source planed to be constructed in Poland. Authors of six out of 23 projects indicated interest in photon energies over 4 keV but only three of them exclusively. Although the number of projects is limited, which is quite understandable given the undefined future of the Polish SRF, such a poll indicates that there exists considerable interest in use of SR of energies that can be provided by a small-scale source. Also, it has to be taken into account that starting 1-st July 2004 Poland will become a member of ESRF Consortium and user's demand for the beam-time in hard X-ray range will be, at list partially, satisfied on more regular basis at ESRF. It is recognized that SR users are the most interested in use of radiation from insertion devices, preferably undulators, because of the beam quality, brightness and stability that enable studies of microscopic samples, high energy resolution, and fast data acquisition. There exist also considerable interest in radiation of controlled polarization (circular/eliptical/linear) provided by undulators of special construction. Similarly attractive are undulators which allow for fast tuning of photon energy while maintaining stability of the beam. Such improved radiation sources of third generation have become available recently, thanks to development of accurate design and manufacture of complex magnet systems and due to improved control techniques. Several possibilities concerning the source for Polish SRF, are being evaluated. For obvious reasons, solutions which could be accommodated in realistic budget, of the order of 10 7 eur have been looked for. At first, solutions similar to, those adopted for

  13. Polarizer design for millimeter-wave plasma diagnostics

    DEFF Research Database (Denmark)

    Leipold, Frank; Salewski, Mirko; Jacobsen, Asger Schou

    2013-01-01

    Radiation from magnetized plasmas is in general elliptically polarized. In order to convert the elliptical polarization to linear polarization, mirrors with grooved surfaces are currently employed in our collective Thomson scattering diagnostic at ASDEX Upgrade. If these mirrors can be substituted...

  14. A bromine-based dichroic X-ray polarization analyser

    CERN Document Server

    Collins, S P; Brown, S D; Thompson, P

    2001-01-01

    We have demonstrated the advantages offered by dichroic X-ray polarization filters for linear polarization analysis, and describe such a device, based on a dibromoalkane/urea inclusion compound. The polarizer has been successfully tested by analysing the polarization of magnetic diffraction from holmium.

  15. AGS - The ISR computer program for synchrotron design, orbit analysis and insertion matching

    International Nuclear Information System (INIS)

    Keil, E.; Marti, Y.; Montague, B.W.; Sudboe, A.

    1975-01-01

    This is a detailed guide to the use of the current version of a FORTRAN program for carrying out computations required in the design or modification of alternating-gradient synchrotrons and storage rings. The program, which runs on the CDC 7600 computer at CERN, computes linear transformation functions, and modifications of parameters to achieve specified properties; it tracks sets of particle trajectories, finds closed orbits when elements of the structure are displaced, computes the equilibrium orbit, designs closed-orbit bumps, tracks betatron functions through the structure, and matches insertions in the structure to specified betatron and dispersion functions. The report supersedes CERN 69-5 (AGS - The ISR computer system for synchrotron design and orbit analysis, by E. Keil and P. Strolin). (Author)

  16. Synchrotron Radiation Total Reflection X-ray Fluorescence Spectroscopy for Microcontamination Analysis on Silicon Wafer Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Takaura, Norikatsu

    1997-10-01

    As dimensions in state-of-the-art CMOS devices shrink to less than 0.1 pm, even low levels of impurities on wafer surfaces can cause device degradation. Conventionally, metal contamination on wafer surfaces is measured using Total Reflection X-Ray Fluorescence Spectroscopy (TXRF). However, commercially available TXRF systems do not have the necessary sensitivity for measuring the lower levels of contamination required to develop new CMOS technologies. In an attempt to improve the sensitivity of TXRF, this research investigates Synchrotron Radiation TXRF (SR TXRF). The advantages of SR TXRF over conventional TXRF are higher incident photon flux, energy tunability, and linear polarization. We made use of these advantages to develop an optimized SR TXRF system at the Stanford Synchrotron Radiation Laboratory (SSRL). The results of measurements show that the Minimum Detection Limits (MDLs) of SR TXRF for 3-d transition metals are typically at a level-of 3x10{sup 8} atoms/cm{sup 2}, which is better than conventional TXRF by about a factor of 20. However, to use our SR TXRF system for practical applications, it was necessary to modify a commercially available Si (Li) detector which generates parasitic fluorescence signals. With the modified detector, we could achieve true MDLs of 3x10{sup 8} atoms/cm{sup 2} for 3-d transition metals. In addition, the analysis of Al on Si wafers is described. Al analysis is difficult because strong Si signals overlap the Al signals. In this work, the Si signals are greatly reduced by tuning the incident beam energy below the Si K edge. The results of our measurements show that the sensitivity for Al is limited by x-ray Raman scattering. Furthermore, we show the results of theoretical modeling of SR TXRF backgrounds consisting of the bremsstrahlung generated by photoelectrons, Compton scattering, and Raman scattering. To model these backgrounds, we extended conventional theoretical models by taking into account several aspects particular

  17. Hyperentanglement concentration for polarization-spatial-time-bin hyperentangled photon systems with linear optics

    Science.gov (United States)

    Wang, Hong; Ren, Bao-Cang; Alzahrani, Faris; Hobiny, Aatef; Deng, Fu-Guo

    2017-10-01

    Hyperentanglement has significant applications in quantum information processing. Here we present an efficient hyperentanglement concentration protocol (hyper-ECP) for partially hyperentangled Bell states simultaneously entangled in polarization, spatial-mode and time-bin degrees of freedom (DOFs) with the parameter-splitting method, where the parameters of the partially hyperentangled Bell states are known to the remote parties. In this hyper-ECP, only one remote party is required to perform some local operations on the three DOFs of a photon, only the linear optical elements are considered, and the success probability can achieve the maximal value. Our hyper-ECP can be easily generalized to concentrate the N-photon partially hyperentangled Greenberger-Horne-Zeilinger states with known parameters, where the multiple DOFs have largely improved the channel capacity of long-distance quantum communication. All of these make our hyper-ECP more practical and useful in high-capacity long-distance quantum communication.

  18. The Use of Orthogonal Polarizations in Microwave Imagery of Isolated Canine Kidney

    Science.gov (United States)

    Larsen, L. E.; Jacobi, J. H.

    1980-06-01

    A method of imaging biological targets using microwave radiation at a frequency of 4 GHz is presented. Linearly polarized radiation is transmitted through an isolated canine kidney and received with co-polarized and cross-polarized antennas. Images are displayed as the spatial variation of the magnitude of the transmission scattering parameter S21 for each mode of polarization. The relationship between the spatial variation of the magnitude of S21 and canine renal anatomy is discussed. It is shown that within the kidney the cross-polarized image tends to emphasize linear or piecewise linear structures, whereas the co-polarized image balances renal cortical lobulations.

  19. Variations of Synchrotron Radio Emissions from Jupiter's Inner Radiation Belt

    Science.gov (United States)

    Lou, Y.-Q.

    2017-09-01

    Variations of Synchrotron Radio Emissions from Jupiter's Inner Radiation Belt Yu-Qing Lou* Physics Department, Tsinghua Centre for Astrophysics (THCA), Tsinghua-National Astronomical Observatories of China (NAOC) joint Research Centre for Astrophysics, Tsinghua University, Beijing 100084, China We describe the basic phenommenology of quasi-periodic 40 minute (QP-40) polar burst activities of Jupiter and their close correlation with the solar wind speed variations at the Jovian magnetosphere. Physically, relativistic electrons of QP-40 bursts most likely come from the circumpolar regions of the inner radiation belt (IRB) which gives off intense synchroton radio emissions in a wide wavelength range. Such relativistic electron bursts also give rise to beamed low-frequency radio bursts along polar magnetic field lines with distinct polarizations from Jupiter's two polar regions. Jovian aurora activities are expected to be also affected by such QP-40 burst activities. We present evidence of short-term (typical timescales shorter than an hour) variabilities of the IRB at 6cm wavelength and describe recent joint radio telescope observation campaign to monitor Jupiter in coordination with JUNO spacecraft. Except for low-frequency polarization features, we anticipate JUNO to detect QP-40 activities from both polar regions during the arrival of high-speed solar wind with intermittency. References 1. Y.-Q. Lou, The Astrophysical Journal, 548, 460 (2001). 2. Y.-Q. Lou, and C. Zheng, Mon. Not. Roy. Astron. Soc. Letters, 344, L1 (2003). 3. Y.-Q. Lou, H. G. Song, Y.Y. Liu, and M. Yang, Mon. Not. Roy. Astron. Soc. Letters, 421, L62 (2012). 4. Y.-Q. Lou, Geophysical Research Letters, 23, 609 (1996). 5. Y.-Q. Lou, Journal of Geophysical Research, 99, 14747 (1994). 6. G. R. Gladstone, et al., Nature, 415, 1000 (2002).

  20. SOFT: a synthetic synchrotron diagnostic for runaway electrons

    Science.gov (United States)

    Hoppe, M.; Embréus, O.; Tinguely, R. A.; Granetz, R. S.; Stahl, A.; Fülöp, T.

    2018-02-01

    Improved understanding of the dynamics of runaway electrons can be obtained by measurement and interpretation of their synchrotron radiation emission. Models for synchrotron radiation emitted by relativistic electrons are well established, but the question of how various geometric effects—such as magnetic field inhomogeneity and camera placement—influence the synchrotron measurements and their interpretation remains open. In this paper we address this issue by simulating synchrotron images and spectra using the new synthetic synchrotron diagnostic tool SOFT (Synchrotron-detecting Orbit Following Toolkit). We identify the key parameters influencing the synchrotron radiation spot and present scans in those parameters. Using a runaway electron distribution function obtained by Fokker-Planck simulations for parameters from an Alcator C-Mod discharge, we demonstrate that the corresponding synchrotron image is well-reproduced by SOFT simulations, and we explain how it can be understood in terms of the parameter scans. Geometric effects are shown to significantly influence the synchrotron spectrum, and we show that inherent inconsistencies in a simple emission model (i.e. not modeling detection) can lead to incorrect interpretation of the images.

  1. A New Limit on CMB Circular Polarization from SPIDER

    Science.gov (United States)

    Nagy, J. M.; Ade, P. A. R.; Amiri, M.; Benton, S. J.; Bergman, A. S.; Bihary, R.; Bock, J. J.; Bond, J. R.; Bryan, S. A.; Chiang, H. C.; Contaldi, C. R.; Doré, O.; Duivenvoorden, A. J.; Eriksen, H. K.; Farhang, M.; Filippini, J. P.; Fissel, L. M.; Fraisse, A. A.; Freese, K.; Galloway, M.; Gambrel, A. E.; Gandilo, N. N.; Ganga, K.; Gudmundsson, J. E.; Halpern, M.; Hartley, J.; Hasselfield, M.; Hilton, G.; Holmes, W.; Hristov, V. V.; Huang, Z.; Irwin, K. D.; Jones, W. C.; Kuo, C. L.; Kermish, Z. D.; Li, S.; Mason, P. V.; Megerian, K.; Moncelsi, L.; Morford, T. A.; Netterfield, C. B.; Nolta, M.; Padilla, I. L.; Racine, B.; Rahlin, A. S.; Reintsema, C.; Ruhl, J. E.; Runyan, M. C.; Ruud, T. M.; Shariff, J. A.; Soler, J. D.; Song, X.; Trangsrud, A.; Tucker, C.; Tucker, R. S.; Turner, A. D.; Van Der List, J. F.; Weber, A. C.; Wehus, I. K.; Wiebe, D. V.; Young, E. Y.

    2017-08-01

    We present a new upper limit on cosmic microwave background (CMB) circular polarization from the 2015 flight of Spider, a balloon-borne telescope designed to search for B-mode linear polarization from cosmic inflation. Although the level of circular polarization in the CMB is predicted to be very small, experimental limits provide a valuable test of the underlying models. By exploiting the nonzero circular-to-linear polarization coupling of the half-wave plate polarization modulators, data from Spider's 2015 Antarctic flight provide a constraint on Stokes V at 95 and 150 GHz in the range 33< {\\ell }< 307. No other limits exist over this full range of angular scales, and Spider improves on the previous limit by several orders of magnitude, providing 95% C.L. constraints on {\\ell }({\\ell }+1){C}{\\ell }{VV}/(2π ) ranging from 141 to 255 μK2 at 150 GHz for a thermal CMB spectrum. As linear CMB polarization experiments become increasingly sensitive, the techniques described in this paper can be applied to obtain even stronger constraints on circular polarization.

  2. A New Limit on CMB Circular Polarization from SPIDER

    Energy Technology Data Exchange (ETDEWEB)

    Nagy, J. M.; Ade, P. A. R.; Amiri, M.; Benton, S. J.; Bergman, A. S.; Bihary, R.; Bock, J. J.; Bond, J. R.; Bryan, S. A.; Chiang, H. C.; Contaldi, C. R.; Doré, O.; Duivenvoorden, A. J.; Eriksen, H. K.; Farhang, M.; Filippini, J. P.; Fissel, L. M.; Fraisse, A. A.; Freese, K.; Galloway, M.; Gambrel, A. E.; Gandilo, N. N.; Ganga, K.; Gudmundsson, J. E.; Halpern, M.; Hartley, J.; Hasselfield, M.; Hilton, G.; Holmes, W.; Hristov, V. V.; Huang, Z.; Irwin, K. D.; Jones, W. C.; Kuo, C. L.; Kermish, Z. D.; Li, S.; Mason, P. V.; Megerian, K.; Moncelsi, L.; Morford, T. A.; Netterfield, C. B.; Nolta, M.; Padilla, I. L.; Racine, B.; Rahlin, A. S.; Reintsema, C.; Ruhl, J. E.; Runyan, M. C.; Ruud, T. M.; Shariff, J. A.; Soler, J. D.; Song, X.; Trangsrud, A.; Tucker, C.; Tucker, R. S.; Turner, A. D.; List, J. F. Van Der; Weber, A. C.; Wehus, I. K.; Wiebe, D. V.; Young, E. Y.

    2017-08-01

    We present a new upper limit on CMB circular polarization from the 2015 flight of SPIDER, a balloon-borne telescope designed to search for $B$-mode linear polarization from cosmic inflation. Although the level of circular polarization in the CMB is predicted to be very small, experimental limits provide a valuable test of the underlying models. By exploiting the non-zero circular-to-linear polarization coupling of the HWP polarization modulators, data from SPIDER's 2015 Antarctic flight provides a constraint on Stokes $V$ at 95 and 150 GHz from $33<\\ell<307$. No other limits exist over this full range of angular scales, and SPIDER improves upon the previous limit by several orders of magnitude, providing 95% C.L. constraints on $\\ell (\\ell+1)C_{\\ell}^{VV}/(2\\pi)$ ranging from 141 $\\mu K ^2$ to 203 $\\mu K ^2$ at 150 GHz for a thermal CMB spectrum. As linear CMB polarization experiments become increasingly sensitive, the techniques described in this paper can be applied to obtain stronger constraints on circular polarization.

  3. Network measurements at the heavy ion synchrotron SIS at GSI

    International Nuclear Information System (INIS)

    Vossbeck, P.; Pschorn, I.; Gebhard, Moritz

    1999-01-01

    The Heavy Ion Synchrotron SIS forms together with the Linear Accelerator UNILAC and the Storage Ring ESR the accelerator complex of the Gesellschaft fuer Schwerionenforschung in Darmstadt. It accelerates heavy ions up to Uranium to 1 GeV/amu. The accelerators and beamlines have been surveyed and aligned using the TASA method. For SIS a network was established in order to survey the synchrotron with the TASA method. Goal of a diploma thesis was to establish an alternative network for a Laser Tracker instrument and to reach error ellipsoids below 30 μm. In this paper a comparison of the two methods is given. Since the Tracker measurements are done automatically only one person is needed. That reduces the man power. Time consumption for both methods is about the same, although much more network points were used with the Laser Tracker method. As a consequence of the larger number of network points the homogeneity of the results is better. (authors)

  4. Photoanisotropic polarization gratings beyond the small recording angle regime

    NARCIS (Netherlands)

    Xu, M.; De Boer, D.K.G.; Van Heesch, C.M.; Wachters, A.J.H.; Urbach, H.P.

    2010-01-01

    Polarization gratings can be realized by polarization holographic recording in photoanisotropic materials. In this paper, we study two types of polarization gratings. One is recorded with two orthogonally circularly (OC) polarized beams and the other one with two orthogonally linearly (OL) polarized

  5. Quantum deformation of the angular distributions of synchrotron radiation. Emission from particles in the first excited state

    Energy Technology Data Exchange (ETDEWEB)

    Bagrov, V.G. [Tomsk State University, Department of Physics, Tomsk (Russian Federation); SB RAS, Tomsk Institute of High Current Electronics, Tomsk (Russian Federation); University of Sao Paulo, Institute of Physics, Sao Paulo (Brazil); Burimova, A.N. [Tomsk State University, Department of Physics, Tomsk (Russian Federation); University of Sao Paulo, Institute of Physics, Sao Paulo (Brazil); Gitman, D.M.; Levin, A.D. [University of Sao Paulo, Institute of Physics, Sao Paulo (Brazil)

    2012-02-15

    The exact expressions for the characteristics of synchrotron radiation of charged particles in the first excited state are obtained in analytical form using quantum theory methods. We performed a detailed analysis of the angular distribution structure of radiation power and its polarization for particles with spin 0 and 1/2. It is shown that the exact quantum calculations lead to results that differ substantially from the predictions of classical theory. (orig.)

  6. Research on generating various polarization-modes in polarized illumination system

    Science.gov (United States)

    Huang, Jinping; Lin, Wumei; Fan, Zhenjie

    2013-08-01

    With the increase of the numerical aperture (NA), the polarization of light affects the imaging quality of projection lens more significantly. On the contrary, according to the mask pattern, the resolution of projection lens can be improved by using the polarized illumination. That is to say, using the corresponding polarized beam (or polarization-mode) along with the off-axis illumination will improve the resolution and the imaging quality of the of projection lens. Therefore, the research on the generation of various polarization modes and its conversion methods become more and more important. In order to realize various polarization modes in polarized illumination system, after read a lot of references, we provide a way that fitting for the illumination system with the wavelength of 193nm.Six polarization-modes and a depolarized mode are probably considered. Wave-plate stack is used to generate linearly polarization-mode, which have a higher degree polarization. In order to generate X-Y and Y-X polarization mode, the equipment consisting of four sectors of λ/2 wave plate was used. We combined 16 sectors of λ/2 wave plate which have different orientations of the "slow" axis to generate radial and azimuthal polarization. Finally, a multi-polarization control device was designed. Using the kind of multi-polarization control device which applying this method could help to choose the polarization modes conveniently and flexibility for the illumination system.

  7. 50 years of synchrotrons. Early synchrotrons in Britain, and early work for CERN. - The CERN synchrotrons. Lectures

    International Nuclear Information System (INIS)

    Lawson, J.; Brianti, G.

    1997-01-01

    In the first report, 'Early synchrotrons in Britain, and early work for CERN', John Lawson gives an extended account of the material presented at the John Adams lecture, and at the same time a revised and shortened version of RAL report 97-011, which contains fuller archival references and notes. During the period covered by this report there was extensive work in Russia, where the principle of phase stability had been discovered in 1944 by Veksler. Unfortunately, all experimental work was kept secret until Veksler's talk at the first 'Atoms for Peace' conference at Geneva in August 1955. In the second lecture, 'The CERN Synchrotrons', Giorgio Brianti outlines the history of alternating-gradient synchrotrons from 1953/54 until today. In preparing this lecture he was confronted with a vast amount of material, while the time at his disposal was not even one minute per year, implying a time compression factor close to one million. Therefore, he had to exercise drastic choices, which led him to concentrate on CERN hadron synchrotrons and colliders and leave aside the Large Electron-Positron storage ring (LEP). Indeed, LEP was the subject of the John Adams Memorial Lecture in 1990, and it may be treated again in the future in connection with its energy upgrade. Even with these severe limitations, it was impossible to do justice to the number and variety of events and to the ingenuity of the people who have carved the history of CERN and of particle physics on the magnets, radiofrequency cavities, vacuum etc., and on the record performance of our machines. (orig./WL)

  8. Light source for synchrotron radiation x-ray topography study at Beijing Synchrotron Radiation Laboratory (BSRL)

    International Nuclear Information System (INIS)

    Zhao Jiyong; Jiang Jianhua; Tian Yulian

    1992-01-01

    Characteristics of the synchrotron radiation source for X-ray topography study at Beijing Synchrotron Radiation Laboratory (BSRL) is described, local geometrical resolution of topographies is discussed, and the diffracting intensities of white beam topography is given

  9. 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

  10. The polarized atomic-beam target for the EDDA experiment and the time-reversal invariance test at COSY

    Science.gov (United States)

    Eversheim, P. D.; Altmeier, M.; Felden, O.

    1997-02-01

    For the the EDDA experiment, which was set up to measure the p¯-p¯ excitation function during the acceleration ramp of the cooler synchrotron COSY at Jülich, a polarized atomic-beam target was designed regarding the restrictions imposed by the geometry of the EDDA detector. Later, when the time-reversal invariance experiment is to be performed, the EDDA detector will serve as efficient internal polarimeter and the source has to deliver tensor polarized deuterons. The modular design of this polarized atomic-beam target that allows to meet these conditions will be discussed in comparison to other existing polarized atomic-beam targets.

  11. Optical systems for synchrotron radiation. Lecture 1. Introductory topics. Revision

    International Nuclear Information System (INIS)

    Howells, M.R.

    1986-02-01

    Various fundamental topics are considered which underlie the design and use of optical systems for synchrotron radiation. The point of view of linear system theory is chosen which acts as a unifying concept throughout the series. In this context the important optical quantities usually appear as either impulse response functions (Green's functions) or frequency transfer functions (Fourier Transforms of the Green's functions). Topics include the damped harmonic oscillator, free-space optical field propagation, optical properties of materials, dispersion, and the Kramers-Kronig relations

  12. Atomic physics research with synchrotron radiation

    International Nuclear Information System (INIS)

    Crasemann, B.; Wuilleumier, F.

    1985-01-01

    This chapter discusses applications of synchrotron light in atomic and molecular physics. Use of the radiation from storage rings has expanded and lent access to new areas of absorption and photoemission spectroscopy and scattering experiments. Techniques applied in connection with synchrotron radiation are discussed including absorption spectroscopy, photoelectron spectroscopy, fluorescence spectroscopy and X-ray scattering. Problem areas that are being studied by the techniques mentioned above are discussed. Synchrotron radiation has provided the means for measuring the threshold-excitation and interference effects that signal the breakdown of the two-step model of atomic excitation/deexcitation. Synchrotron radiation provides more means of excited-state photoionization measurements

  13. Ultra-thin, single-layer polarization rotator

    Directory of Open Access Journals (Sweden)

    T. V. Son

    2016-08-01

    Full Text Available We demonstrate light polarization control over a broad spectral range by a uniform layer of vanadium dioxide as it undergoes a phase transition from insulator to metal. Changes in refractive indices create unequal phase shifts on s- and p-polarization components of incident light, and rotation of linear polarization shows intensity modulation by a factor of 103 when transmitted through polarizers. This makes possible polarization rotation devices as thin as 50 nm that would be activated thermally, optically or electrically.

  14. Studies of magnetism and exchange scattering in solids using synchrotron radiation and spin polarized photoemission. Final technical report, June 1, 1981-May 31, 1984

    International Nuclear Information System (INIS)

    Rothberg, G.M.

    1984-01-01

    Progress has been made toward developing Spin Polarized EXAFS (SPEXAFS) as a technique for studying magnetism in solids. The first observations have been made of EXAFS by means of photoemission with sufficient data to permit a traditional Fourier-transform analysis of atomic structure. Some of the advantages of photoelectron detection of EXAFS are: (1) vuv light may be used thereby extending greatly the useable range of photon energies; (2) the number of elements that may be studied for surface EXAFS is increased; (3) the possibility exists for measurements that cannot be done in other ways. In addition to its intrinsic interest, this result is crucial to the study of the spin dependence of EXAFS. These measurements were carried out on the vuv storage ring at the National Synchrotron Light Source. Data obtained on the spin dependence of EXAFS in MnF 2 at room temperature tentatively show dependence of the Mn absorber atom phase shift on the exchange interaction within the absorber atom. This effect has not been discussed theoretically. Preliminary observations have been made of the Fano resonance in Mn 3d photoemission at the 3p to 3d threshold

  15. Quantitative analysis with advanced compensated polarized light microscopy on wavelength dependence of linear birefringence of single crystals causing arthritis

    Science.gov (United States)

    Takanabe, Akifumi; Tanaka, Masahito; Taniguchi, Atsuo; Yamanaka, Hisashi; Asahi, Toru

    2014-07-01

    To improve our ability to identify single crystals causing arthritis, we have developed a practical measurement system of polarized light microscopy called advanced compensated polarized light microscopy (A-CPLM). The A-CPLM system is constructed by employing a conventional phase retardation plate, an optical fibre and a charge-coupled device spectrometer in a polarized light microscope. We applied the A-CPLM system to measure linear birefringence (LB) in the visible region, which is an optical anisotropic property, for tiny single crystals causing arthritis, i.e. monosodium urate monohydrate (MSUM) and calcium pyrophosphate dihydrate (CPPD). The A-CPLM system performance was evaluated by comparing the obtained experimental data using the A-CPLM system with (i) literature data for a standard sample, MgF2, and (ii) experimental data obtained using an established optical method, high-accuracy universal polarimeter, for the MSUM. The A-CPLM system was found to be applicable for measuring the LB spectra of the single crystals of MSUM and CPPD, which cause arthritis, in the visible regions. We quantitatively reveal the large difference in LB between MSUM and CPPD crystals. These results demonstrate the usefulness of the A-CPLM system for distinguishing the crystals causing arthritis.

  16. Infrared synchrotron radiation from electron storage rings

    International Nuclear Information System (INIS)

    Duncan, W.D.; Williams, G.P.

    1983-01-01

    Simple and useful approximations, valid at infrared wavelengths, to the equations for synchrotron radiation are presented and used to quantify the brightness and power advantage of current synchrotron radiation light sources over conventional infrared broadband laboratory sources. The Daresbury Synchrotron Radiation Source (SRS) and the Brookhaven National Synchrotron Light Source (vacuum ultraviolet) [NSLS(VUV)] storage rings are used as examples in the calculation of the properties of infrared synchrotron radiation. The pulsed nature of the emission is also discussed, and potential areas of application for the brightness, power, and time structure advantages are presented. The use of infrared free electron lasers and undulators on the next generation of storage ring light sources is briefly considered

  17. Construction and performance of BL28 of the Photon Factory for circularly polarized synchrotron radiation

    International Nuclear Information System (INIS)

    Kagoshima, Y.; Muto, S.; Miyahara, T.; Koide, T.; Yamamoto, S.; Kitamura, H.

    1992-01-01

    A branch beamline, BL28A, has been constructed for the application of circularly polarized vacuum ultraviolet radiation. The radiation can be obtained in the helical undulator operation mode of an insertion device, EMPW number-sign 28, which is also cut for elliptically polarized hard x-ray radiation. T first harmonic of the helical undulator radiation can be tuned from 40 to 350 eV with its corresponding K value from 3 to 0.2. A monochromator working basically with constant deviation optics was installed, and has started its operation. A circularly polarized flux of ∼10 10 photons/s has been achieved with energy resolution of around 500--1000 at the first harmonic peak. The circular polarization after the monochromator was estimated to be higher than 70% by comparing theory and experiment on the magnetic circular dichroism of nickel films in the 3p-3d excitation region. The design philosophy of the beamline and recent results on the performance tests are presented

  18. Construction and performance of BL28 of the Photon Factory for circularly polarized synchrotron radiation

    Science.gov (United States)

    Kagoshima, Yasushi; Muto, Sadatsugu; Miyahara, Tsuneaki; Koide, Tsuneharu; Yamamoto, Shigeru; Kitamura, Hideo

    1992-01-01

    A branch beamline, BL28A, has been constructed for the application of circularly polarized vacuum ultraviolet radiation. The radiation can be obtained in the helical undulator operation mode of an insertion device, EMPW♯28, which is also cut for elliptically polarized hard x-ray radiation. T first harmonic of the helical undulator radiation can be tuned from 40 to 350 eV with its corresponding K value from 3 to 0.2. A monochromator working basically with constant deviation optics was installed, and has started its operation. A circularly polarized flux of ˜1010 photons/s has been achieved with energy resolution of around 500-1000 at the first harmonic peak. The circular polarization after the monochromator was estimated to be higher than 70% by comparing theory and experiment on the magnetic circular dichroism of nickel films in the 3p-3d excitation region. The design philosophy of the beamline and recent results on the performance tests are presented.

  19. Kinetics of non-equilibrium processes in non-linear crystals of lithium borates excited with synchrotron radiation

    CERN Document Server

    Ogorodnikov, I N; Isaenko, L I; Zinin, E I; Kruzhalov, A V

    2000-01-01

    The paper presents the results of a study of the LiB sub 3 O sub 5 and Li sub 2 B sub 4 O sub 7 crystals by the use of the luminescent spectroscopy with the sub-nanosecond time resolution under excitation of the high-power synchrotron radiation. The commonness in the origin of the non-equilibrium processes in these crystals as well as the observed differences in the luminescence manifestations is discussed.

  20. Kinetics of non-equilibrium processes in non-linear crystals of lithium borates excited with synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Ogorodnikov, I.N. E-mail: ogo@dpt.ustu.ru; Pustovarov, V.A.; Isaenko, L.I.; Zinin, E.I.; Kruzhalov, A.V

    2000-06-21

    The paper presents the results of a study of the LiB{sub 3}O{sub 5} and Li{sub 2}B{sub 4}O{sub 7} crystals by the use of the luminescent spectroscopy with the sub-nanosecond time resolution under excitation of the high-power synchrotron radiation. The commonness in the origin of the non-equilibrium processes in these crystals as well as the observed differences in the luminescence manifestations is discussed.

  1. Synchrotron Elettra. Status and perspectives

    International Nuclear Information System (INIS)

    Remec, I.

    1992-01-01

    Synchrotron radiation and the possibilities for its applications are shortly presented. Elettra, the third generation synchrotron, now under construction in Trieste, Italy, is briefly described and its main characteristics are given. Current activities in Slovenia, related to Elettra, are presented. (author) [sl

  2. Synchrotron radiation instrumentation collaborative access team SRI-CAT sector 4

    International Nuclear Information System (INIS)

    1997-01-01

    The research objective for this sector of the Advanced Photon Source (APS) is the development of sources and applications of polarized x-rays covering the energy range from 0.5 to 50 keV. Both linearly and circularly polarized x-rays have been very successfully applied to the study of magnetic properties of materials. However, the applications have been limited due primarily to the lack of energy-tunable, high-brilliance x-ray beams with adjustable polarization properties. It is the authors' intention that this sector will to some extent ameliorate that situation. They are confident that optics can be fabricated to simultaneously provide a high-quality beam with adjustable polarization in the energy range above 5 keV using the standard undulator A as a source. That is not the case below 5 keV, and hence they are planning to develop and install a helical undulator that can generate beams of variable (linear or circular) polarization in this lower energy range. Magnetic circular dichroism, resonant and non-resonant magnetic x-ray scattering, and other polarization-dependent phenomena will be investigated using hard x-rays. Techniques similar to those described for the hard x-rays plus spatially resolved, spin-polarized photoemission studies will be developed and used with the intermediate energy x-rays. They have incorporated some features not directly related to polarization studies, which were not available elsewhere on SRI-CAT beamlines. One of those features is a large vacuum tank immediately downstream of the ratchet wall into which high heat load beamline components can be installed and tested. A second feature is a mirror capable of focusing the white beam for high heat flux optical-component development and other uses. The insertion-device development, polarization programs, and beamline component testing all fall well within the existing scope of the SRI CAT programs

  3. Synchrotron radiation instrumentation collaborative access team SRI-CAT sector 4

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-08-01

    The research objective for this sector of the Advanced Photon Source (APS) is the development of sources and applications of polarized x-rays covering the energy range from 0.5 to 50 keV. Both linearly and circularly polarized x-rays have been very successfully applied to the study of magnetic properties of materials. However, the applications have been limited due primarily to the lack of energy-tunable, high-brilliance x-ray beams with adjustable polarization properties. It is the authors` intention that this sector will to some extent ameliorate that situation. They are confident that optics can be fabricated to simultaneously provide a high-quality beam with adjustable polarization in the energy range above 5 keV using the standard undulator A as a source. That is not the case below 5 keV, and hence they are planning to develop and install a helical undulator that can generate beams of variable (linear or circular) polarization in this lower energy range. Magnetic circular dichroism, resonant and non-resonant magnetic x-ray scattering, and other polarization-dependent phenomena will be investigated using hard x-rays. Techniques similar to those described for the hard x-rays plus spatially resolved, spin-polarized photoemission studies will be developed and used with the intermediate energy x-rays. They have incorporated some features not directly related to polarization studies, which were not available elsewhere on SRI-CAT beamlines. One of those features is a large vacuum tank immediately downstream of the ratchet wall into which high heat load beamline components can be installed and tested. A second feature is a mirror capable of focusing the white beam for high heat flux optical-component development and other uses. The insertion-device development, polarization programs, and beamline component testing all fall well within the existing scope of the SRI CAT programs.

  4. Is the GeV-TeV emission of PKS 0447-439 from the proton synchrotron radiation?

    Science.gov (United States)

    Gao, Quan-Gui; Lu, Fang-Wu; Ma, Ju; Ren, Ji-Yang; Li, Huai-Zhen

    2018-06-01

    We study the multi-wavelength emission features of PKS 0447-439 in the frame of the one-zone homogeneous lepto-hadronic model. In this model, we assumed that the steady power-laws with exponential cut-offs distributions of protons and electrons are injected into the source. The non-linear time-dependent kinematic equations, describing the evolution of protons, electrons and photons, are defined; these equations self-consistently involve synchrotron radiation of protons, photon-photon interaction, synchrotron radiation of electron/positron pairs, inverse Compton scattering and synchrotron self-absorption. The model is applied to reproduce the multi-wavelength spectrum of PKS 0447-439. Our results indicate that the spectral energy distribution (SED) of PKS 0447-439 can be reproduced well by the model. In particular, the GeV-TeV emission is produced by the synchrotron radiation of relativistic protons. The physically plausible solutions require the magnetic strength 10 G≲ B ≲ 100 G. We found that the observed spectrum of PKS 0447-439 can be reproduced well by the model whether z = 0.16 or z = 0.2, and the acceptable upper limit of redshift is z=0.343.

  5. Crosstalk cancellation on linearly and circularly polarized communications satellite links

    Science.gov (United States)

    Overstreet, W. P.; Bostian, C. W.

    1979-01-01

    The paper discusses the cancellation network approach for reducing crosstalk caused by depolarization on a dual-polarized communications satellite link. If the characteristics of rain depolarization are sufficiently well known, the cancellation network can be designed in a way that reduces system complexity, the most important parameter being the phase of the cross-polarized signal. Relevant theoretical calculations and experimental data are presented. The simplicity of the cancellation system proposed makes it ideal for use with small domestic or private earth terminals.

  6. High-intensity laser synchrotron x-ray source

    International Nuclear Information System (INIS)

    Pogorelsky, I.V.

    1995-10-01

    A laser interacting with a relativistic electron beam behaves like a virtual wiggler of an extremely short period equal to half of the laser wavelength. This approach opens a route to relatively compact, high-brightness x-ray sources alternative or complementary to conventional synchrotron light sources. Although not new, the Laser Synchrotron Light Source (LSLS) concept is still waiting for a convincing demonstration. Available at the BNL's Accelerator Test Facility (ATF), a high-brightness electron beam and the high-power C0 2 laser may be used as prototype LSLS brick stones. In a feasible demonstration experiment, 10-GW, 100-ps C0 2 laser beam will be brought to a head-on collision with a 10-ps, 0.5-nC, 70 MeV electron bunch. Flashes of well-collimated, up to 9.36-keV (∼ Angstrom) x-rays of 10-ps pulse duration, with a flux of ∼10 19 photons/sec will be produced via linear Compton backscattering. The x-ray spectrum is tunable proportionally to a variable e-beam energy. A natural short-term extension of the proposed experiment would be further enhancement of the x-ray flux to a 10 21 -10 22 photons/sec level, after the ongoing ATF CO 2 laser upgrade to 1 TW peak power and electron bunch shortening to 3 ps. The ATF LSLS x-ray beamline, exceeding by orders of magnitude the peak fluxes attained at the National Synchrotron Light Source (NSLS) x-ray storage ring, may become attractive for certain users, e.g., for biological x-ray microscopy. In addition, a terawatt CO 2 laser will enable harmonic multiplication of the x-ray spectrum via nonlinear Compton scattering

  7. Synchrotron radiation

    International Nuclear Information System (INIS)

    Hallmeier, K.H.; Meisel, A.; Ranft, J.

    1982-01-01

    The physical background and the properties of synchrotron radiation are described. The radiation offers many useful applications in the fields of spectroscopy and structural investigations. Some examples are given

  8. A study on radiation shielding and safety analysis for a synchrotron radiation beamline

    International Nuclear Information System (INIS)

    Asano, Yoshihiro

    2001-03-01

    Methods of shielding design and safety analysis are presented for a beam-line of synchrotron radiation. This paper consists of the shielding and safety study of synchrotron radiation with extremely intense and low energy photon below several hundreds keV, and the study for the behavior of remarkable high-energy photons up to 8 GeV, which can creep into beam-lines. A new shielding design code, STAC8 was developed to estimate the leakage dose outside the beam line hutch (an enclosure of the beam, optical elements or experimental instruments) easily and quickly with satisfactory accuracy. The code can calculate consistently from sources of synchrotron radiation to dose equivalent outside hutches with considering the build up effect and polarization effect. Validity of the code was verified by comparing its calculations with those of Monte Carlo simulations and measurement results of the doses inside the hutch of the BL14C of Photon Factory in the High Energy Accelerator Research Organization (KEK), showing good agreements. The shielding design calculations using STAC8 were carried out to apply to the practical beam-lines with the considering polarization effect and clarified the characteristics of the typical beam-line of the third generation synchrotron radiation facility, SPring-8. In addition, the shielding calculations were compared with the measurement outside the shield wall of the bending magnet beam-line of SPring-8, and showed fairly good agreement. The new shielding problems, which have usually been neglected in shielding designs for existing synchrotron radiation facilities, are clarified through the analysis of the beam-line shielding of SPring-8. The synchrotron radiation from the SPring-8 has such extremely high-intensity involving high energy photons that the scattered synchrotron radiation from the concrete floor of the hutch, the ground shine, causes a seriously high dose. The method of effective shielding is presented. For the estimation of the gas

  9. A study on radiation shielding and safety analysis for a synchrotron radiation beamline

    Energy Technology Data Exchange (ETDEWEB)

    Asano, Yoshihiro [Japan Atomic Energy Research Inst., Kansai Research Establishment, Synchrotron Radiation Research Center, Mikazuhi, Hyogo (Japan)

    2001-03-01

    Methods of shielding design and safety analysis are presented for a beam-line of synchrotron radiation. This paper consists of the shielding and safety study of synchrotron radiation with extremely intense and low energy photon below several hundreds keV, and the study for the behavior of remarkable high-energy photons up to 8 GeV, which can creep into beam-lines. A new shielding design code, STAC8 was developed to estimate the leakage dose outside the beam line hutch (an enclosure of the beam, optical elements or experimental instruments) easily and quickly with satisfactory accuracy. The code can calculate consistently from sources of synchrotron radiation to dose equivalent outside hutches with considering the build up effect and polarization effect. Validity of the code was verified by comparing its calculations with those of Monte Carlo simulations and measurement results of the doses inside the hutch of the BL14C of Photon Factory in the High Energy Accelerator Research Organization (KEK), showing good agreements. The shielding design calculations using STAC8 were carried out to apply to the practical beam-lines with the considering polarization effect and clarified the characteristics of the typical beam-line of the third generation synchrotron radiation facility, SPring-8. In addition, the shielding calculations were compared with the measurement outside the shield wall of the bending magnet beam-line of SPring-8, and showed fairly good agreement. The new shielding problems, which have usually been neglected in shielding designs for existing synchrotron radiation facilities, are clarified through the analysis of the beam-line shielding of SPring-8. The synchrotron radiation from the SPring-8 has such extremely high-intensity involving high energy photons that the scattered synchrotron radiation from the concrete floor of the hutch, the ground shine, causes a seriously high dose. The method of effective shielding is presented. For the estimation of the gas

  10. Protein Data Bank Depositions from Synchrotron Sources

    International Nuclear Information System (INIS)

    Jiang, J.; Sweet, R.

    2004-01-01

    A survey and analysis of Protein Data Bank (PDB) depositions from international synchrotron radiation facilities, based on the latest released PDB entries, are reported. The results ( ) show that worldwide, every year since 1999, more than 50% of the deposited X-ray structures have used synchrotron facilities, reaching 75% by 2003. In this web-based database, all PDB entries among individual synchrotron beamlines are archived, synchronized with the weekly PDB release. Statistics regarding the quality of experimental data and the refined model for all structures are presented, and these are analysed to reflect the impact of synchrotron sources. The results confirm the common impression that synchrotron sources extend the size of structures that can be solved with equivalent or better quality than home sources

  11. The profile of the electron beam in the PTB synchrotron, and its influence on radiometric measurements with synchrotron radiation

    International Nuclear Information System (INIS)

    Kaase, H.

    1976-01-01

    A simple method is described to determine the beam profile in an electron synchrotron; the measured results are compared with calculated values. Moreover, the influence of synchrotron- and betatron-oscillations on synchrotron radiation measurements is discussed, and a method is given to correct this. (orig.) [de

  12. Orthorhombic polar Nd-doped BiFeO3 thin film on MgO substrate

    International Nuclear Information System (INIS)

    Leontyev, I N; Janolin, P-E; Dkhil, B; Yuzyuk, Yu I; El-Marssi, M; Chernyshov, D; Dmitriev, V; Golovko, Yu I; Mukhortov, V M

    2011-01-01

    A Nd-doped BiFeO 3 thin film deposited on MgO substrate was studied by synchrotron diffraction. The ferroelectric nature of the film is proven by in-plane remanent polarization measurement. The highest possible symmetry of the film is determined to be orthorhombic, within the Fm2m space group. Such a structure is rotated by 45 0 with respect to the substrate and is consistent with tilts of oxygen octahedra doubling the unit cell. This polar structure presents a rather unusual strain-accommodation mechanism. (fast track communication)

  13. Use of synchrotron radiation: status and future plans

    Energy Technology Data Exchange (ETDEWEB)

    Kulipanov, G N; Skrinskii, A N [AN SSSR, Novosibirsk. Inst. Yadernoj Fiziki

    1977-07-01

    Modern possibilities of synchrotronous radiation (SR) sources are reviewed. The ways are considered of further development and main fields of application of this class of radiation sources. A wide energy range from 10 eV to 100 keV makes it possible to overlap the whole range of characteristic atomic energies higher than that of a laser. The great brightness of SR permits experiments for a short period of time with high energy resolution Natural SR polarization helps to study spatial anisotropy of objects. Time SR modulation allows to study time characteristics of luminescence, to measure energy of photoelectrons during flight. Perspective is shown of using SR in contact microscopy, X-ray topography, projecting microscopy, scanning and holographic microscopy. Using the full spectrum, it becomes possible to use SR for X-ray structural analysis. Employment of SR for excitation of emission spectra of various elements enables study of electron structure of disperse systems. SR is widely used to investigate the mechanism of luminescence excitation in crystals in the region of vacuum ultraviolet. New possibilities are provided by time and polarization structure of SR for the Moessbauer experiments. Wide range of experiments with SR in the fields of physics, chemistry, biology provides usage of the above radiation in metrology, medicine etc.

  14. Pion Production from Proton Synchrotron Radiation under Strong Magnetic Field in Relativistic Quantum Approach

    Directory of Open Access Journals (Sweden)

    Maruyama Tomoyuki

    2016-01-01

    Full Text Available We study pion production from proton synchrotron radiation in the presence of strong magnetic fields by using the exact proton propagator in a strong magnetic field and explicitly including the anomalous magnetic moment. Results in this exact quantum-field approach do not agree with those obtained in the semi-classical approach. Furthermore, we also find that the anomalous magnetic moment of the proton greatly enhances the production rate about by two orders of magnitude, and that the polar angle of an emitted pion is the same as that of an initial proton.

  15. Polarimetric observations of the innermost regions of relativistic jets in X-ray binaries

    Directory of Open Access Journals (Sweden)

    Russell D.M.

    2013-12-01

    Full Text Available Synchrotron emission from the relativistic jets launched close to black holes and neutron stars can be highly linearly polarized, depending on the configuration of the magnetic field. In X-ray binaries, optically thin synchrotron emission from the compact jets resides at infrared–optical wavelengths. The polarimetric signature of the jets is detected in the infrared and is highly variable in some X-ray binaries. This reveals the magnetic geometry in the compact jet, in a region close enough to the black hole that it is influenced by its strong gravity. In some cases the magnetic field is turbulent and variable near the jet base. In Cyg X–1, the origin of the γ-ray, X-ray and some of the infrared polarization is likely the optically thin synchrotron power law from the inner regions of the jet. In order to reproduce the polarization properties, the magnetic field in this region must be highly ordered, in contrast to other sources.

  16. Effects of Linear-Polarized Near-Infrared Light Irradiation on Chronic Pain

    Directory of Open Access Journals (Sweden)

    Dong Huang

    2012-01-01

    Full Text Available In order to study the efficacy of linear-polarized near-infrared light irradiation (LPNIR on relieving chronic pain in conjunction with nerve block (NB or local block (LB, a 3-week prospective, randomized, double-blind, controlled study was conducted to evaluate the pre- and post-therapy pain intensity. Visual analogue scales (VASs were measured in all patients before and 6 months after therapy visiting the pain clinic during the period of August 2007 to January 2008. A total of 52 patients with either shoulder periarthritis or myofascial pain syndrome or lateral epicondylitis were randomly assigned into two groups by drawing lots. Patients in Group I were treated with NB or LB plus LPNIR; Group II patients, for their part, were treated with the same procedures as in Group I, but not using LPNIR. In both groups, the pain intensity (VAS score decreased significantly immediately after therapy as compared to therapy. There was a significant difference between the test and control groups immediately after therapy (P<0.05, while no effect 6 months later. No side effects were observed. It is concluded that LPNIR is an effective and safe modality to treat various chronic pains, which has synergic effects with NB or LB.

  17. Support for Synchrotron Access by Environmental Scientists

    International Nuclear Information System (INIS)

    Daly, Michael; Madden, Andrew; Palumbo, Anthony; Qafoku, N.

    2006-01-01

    To support ERSP-funded scientists in all aspects of synchrotron-based research at the Advanced Photon Source (APS). This support comes in one or more of the following forms: (1) writing proposals to the APS General User (GU) program, (2) providing time at MRCAT/EnviroCAT beamlines via the membership of the Molecular Environmental Science (MES) Group in MRCAT/EnviroCAT, (3) assistance in experimental design and sample preparation, (4) support at the beamline during the synchrotron experiment, (5) analysis and interpretation of the synchrotron data, and (6) integration of synchrotron experimental results into manuscripts

  18. Design and finite element simulation of vacuum systems for insertion devices in Indus-2 storage ring

    International Nuclear Information System (INIS)

    Yadav, D.P.; Bais, Vijay; Sridhar, R.; Dhimole, Vivek K.; Nitesh, Suthar; Rawal, B.R.; Chogaonkar, Swati

    2015-01-01

    Indus-2 is a 2.5 GeV, 300 mA, Synchrotron Radiation Source (SRS) located at Raja Ramanna Centre for Advanced Technology, Indore. As part of insertion device (ID) development programme two new devices namely, APPLE-2 (Advanced Planar Polarized Light Emitter) type Undulator (also known as U-3 Undulator) and 5 Tesla superconducting wavelength shifter (SWLS) are being developed. APPLE-2 will generate variably polarized synchrotron radiation (SR) required for carrying out magnetic circular dichroism (MCD) and magnetic linear dichroism (MLD) experiments and SWLS will generate synchrotron radiation (SR) with critical photon energy of about 20.8 keV for Energy Dispersive XRD beam line. This paper describes design details and finite element analysis results of various simulations carried out for the vacuum systems of these IDs

  19. Protein Data Bank depositions from synchrotron sources.

    Science.gov (United States)

    Jiang, Jiansheng; Sweet, Robert M

    2004-07-01

    A survey and analysis of Protein Data Bank (PDB) depositions from international synchrotron radiation facilities, based on the latest released PDB entries, are reported. The results (http://asdp.bnl.gov/asda/Libraries/) show that worldwide, every year since 1999, more than 50% of the deposited X-ray structures have used synchrotron facilities, reaching 75% by 2003. In this web-based database, all PDB entries among individual synchrotron beamlines are archived, synchronized with the weekly PDB release. Statistics regarding the quality of experimental data and the refined model for all structures are presented, and these are analysed to reflect the impact of synchrotron sources. The results confirm the common impression that synchrotron sources extend the size of structures that can be solved with equivalent or better quality than home sources.

  20. Undulator-based production of polarized positrons

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, G. [Tel-Aviv Univ. (Israel); Barley, J. [Cornell Univ., Ithaca, NY (United States); Batygin, Y. [SLAC, Menlo Park, CA (US)] (and others)

    2009-05-15

    Full exploitation of the physics potential of a future International Linear Collider will require the use of polarized electron and positron beams. Experiment E166 at the Stanford Linear Accelerator Center (SLAC) has demonstrated a scheme in which an electron beam passes through a helical undulator to generate photons (whose first-harmonic spectrum extended to 7.9 MeV) with circular polarization, which are then converted in a thin target to generate longitudinally polarized positrons and electrons. The experiment was carried out with a one-meter-long, 400-period, pulsed helical undulator in the Final Focus Test Beam (FFTB) operated at 46.6 GeV. Measurements of the positron polarization have been performed at five positron energies from 4.5 to 7.5 MeV. In addition, the electron polarization has been determined at 6.7MeV, and the effect of operating the undulator with a ferrofluid was also investigated. To compare the measurements with expectations, detailed simulations were made with an upgraded version of GEANT4 that includes the dominant polarization-dependent interactions of electrons, positrons, and photons with matter. The measurements agree with calculations, corresponding to 80% polarization for positrons near 6 MeV and 90% for electrons near 7 MeV. (orig.)