Science.gov

Sample records for advanced stokes polarimeter

  1. A spectrum scanning Stokes polarimeter

    NASA Astrophysics Data System (ADS)

    Baur, T. G.; House, L. L.; Hull, H. K.

    1980-02-01

    A photoelectric polarimeter for measuring line profiles in all four Stokes parameters has been built and operates on the SPO 40 cm coronagraph in a joint project with Sacramento Peak Observatory. A description of the optical and electronic systems and the calibration scheme is presented. Performance parameters determined from observations are also given. The polarimeter package consisting of a pair of KDP's, a quarter wave plate, and a polarizing beam splitter is located at the prime focus of the coronagraph. Modulation of the KDP's encodes polarization information into intensity signals that are electronically detected. The scanning of the spectrum, accomplished by rotating the grating, permits Stokes line profiles to be recorded on magnetic tape for processing. The instrument can be used to scan any line from 3900 to 7000 A with a spectral resolution of 0.01 A. Polarizations as small as 0.001% are detectable. The polarimeter and observing system are computer controlled.

  2. Panoramic Stokes-polarimeter

    NASA Astrophysics Data System (ADS)

    Syniavskyi, I. I.; Ivanov, Yu. S.; Vidmachenko, A. P.; Karpov, N. V.

    2013-12-01

    This article proposes optical layout of the imaging polarimeter based on the polarization films to measure the linear polarization of point and extended celestial objects. The spectral range of device is 420-850 nm, field of view 0.25°x0.25°. The device is designed to equip the telescope with a diameter of primary mirror about 400 mm and aperture f/12.

  3. The San Fernando Observatory video Stokes polarimeter

    NASA Technical Reports Server (NTRS)

    Richter, P. H.; Zeldin, L. K.; Loftin, T. A.

    1985-01-01

    A study was conducted to determine the suitability of the San Fernando Observatory's 61 cm (24 inch) aperture vacuum solar telescope and 3 m (118 inch) focal length vacuum spectroheliograph for Stokes Polarimetry measurements. The polarization characteristics of these two instruments was measured by determining their Mueller matrices as a function of telescope orientation, field angle, wavelength, grating type, and position of the measuring beam in the telescope entrance window. In general, the polarizing and depolarizing properties are small so that inversion of the system Mueller matrix will permit the accurate measurement of Stokes profiles for vector magnetic field determination. A proposed polarimeter design based on the use of a TV camera system to simultaneously scan six different polarization components of a given line profile is described. This design, which uses no rotating optics or electronic modulators and makes efficient use of the available irradiance, promises to yield high quality vector magnetograms.

  4. Intrinsic coincident full-Stokes polarimeter using stacked organic photovoltaics.

    PubMed

    Yang, Ruonan; Sen, Pratik; O'Connor, B T; Kudenov, M W

    2017-02-20

    An intrinsic coincident full-Stokes polarimeter is demonstrated by using strain-aligned polymer-based organic photovoltaics (OPVs) that can preferentially absorb certain polarized states of incident light. The photovoltaic-based polarimeter is capable of measuring four Stokes parameters by cascading four semitransparent OPVs in series along the same optical axis. This in-line polarimeter concept potentially ensures high temporal and spatial resolution with higher radiometric efficiency as compared to the existing polarimeter architecture. Two wave plates were incorporated into the system to modulate the S3 Stokes parameter so as to reduce the condition number of the measurement matrix and maximize the measured signal-to-noise ratio. Radiometric calibration was carried out to determine the measurement matrix. The polarimeter presented in this paper demonstrated an average RMS error of 0.84% for reconstructed Stokes vectors after normalized to S0. A theoretical analysis of the minimum condition number of the four-cell OPV design showed that for individually optimized OPV cells, a condition number of 2.4 is possible.

  5. Polarization microscope using a near infrared full-Stokes imaging polarimeter.

    PubMed

    Hsu, Wei-Liang; Davis, Jeffrey; Balakrishnan, Kaushik; Ibn-Elhaj, Mohammed; Kroto, Shona; Brock, Neal; Pau, Stanley

    2015-02-23

    This paper presents a polarization microscope using an infrared (IR) full-Stokes imaging polarimeter. The IR polarimeter utilizes an optimized interference-based micropolarizer design, and provides full-Stokes images with resolution of 1608 × 1208 at 35 frames/second. The device fabrication, instrument calibration, performance evaluation, and measurement results are presented. The measurement error of the imaging polarimeter is less than 3.5%, and the standard deviations are less than 2%.

  6. Full-Stokes polychromatic polarimeter design for Arago

    NASA Astrophysics Data System (ADS)

    Pertenais, Martin; Neiner, Coralie; Petit, Pascal

    2016-07-01

    The UVMag consortium will propose the Arago space mission to the ESA call Cosmic Vision M5. This mission aims at characterizing all kind of stars and their environment simultaneously, to better understand the cycle of matter in our galaxy. It carries a single instrument, a spectropolarimeter, acquiring data from 119 to 888 nm and enabling the determination of the magnetic field of stars thanks to the Zeeman effect. One of the key instrumental point of this project is the development of an efficient polarimeter over the large spectral range and in space. We chose to use a polychromatic temporal modulation to achieve a measurement of all four Stokes parameters: I the intensity, Q and U the linear polarization states, and V the circular polarization. The modulator is composed by several birefringent Magnesium Fluoride plates, optimized to achromatize the extraction efficiency of the Stokes parameters from the FUV to the NIR. This polarization modulator is followed by a polarization beam-splitter to analyze the state of the light. After the polarization analysis, the light goes through a high-resolution spectrograph. We present the theoretical optimization and design of the polarimeter and of the whole instrument, as well as the first laboratory results on this concept.

  7. Development of real-time rotating waveplate Stokes polarimeter using multi-order retardation for ITER poloidal polarimeter

    SciTech Connect

    Imazawa, R. Kawano, Y.; Ono, T.; Itami, K.

    2016-01-15

    The rotating waveplate Stokes polarimeter was developed for ITER (International Thermonuclear Experimental Reactor) poloidal polarimeter. The generalized model of the rotating waveplate Stokes polarimeter and the algorithm suitable for real-time field-programmable gate array (FPGA) processing were proposed. Since the generalized model takes into account each component associated with the rotation of the waveplate, the Stokes parameters can be accurately measured even in unideal condition such as non-uniformity of the waveplate retardation. Experiments using a He-Ne laser showed that the maximum error and the precision of the Stokes parameter were 3.5% and 1.2%, respectively. The rotation speed of waveplate was 20 000 rpm and time resolution of measuring the Stokes parameter was 3.3 ms. Software emulation showed that the real-time measurement of the Stokes parameter with time resolution of less than 10 ms is possible by using several FPGA boards. Evaluation of measurement capability using a far-infrared laser which ITER poloidal polarimeter will use concluded that measurement error will be reduced by a factor of nine.

  8. Development of real-time rotating waveplate Stokes polarimeter using multi-order retardation for ITER poloidal polarimeter

    NASA Astrophysics Data System (ADS)

    Imazawa, R.; Kawano, Y.; Ono, T.; Itami, K.

    2016-01-01

    The rotating waveplate Stokes polarimeter was developed for ITER (International Thermonuclear Experimental Reactor) poloidal polarimeter. The generalized model of the rotating waveplate Stokes polarimeter and the algorithm suitable for real-time field-programmable gate array (FPGA) processing were proposed. Since the generalized model takes into account each component associated with the rotation of the waveplate, the Stokes parameters can be accurately measured even in unideal condition such as non-uniformity of the waveplate retardation. Experiments using a He-Ne laser showed that the maximum error and the precision of the Stokes parameter were 3.5% and 1.2%, respectively. The rotation speed of waveplate was 20 000 rpm and time resolution of measuring the Stokes parameter was 3.3 ms. Software emulation showed that the real-time measurement of the Stokes parameter with time resolution of less than 10 ms is possible by using several FPGA boards. Evaluation of measurement capability using a far-infrared laser which ITER poloidal polarimeter will use concluded that measurement error will be reduced by a factor of nine.

  9. Signal-to-noise analysis of Stokes parameters in division of focal plane polarimeters.

    PubMed

    Perkins, Robert; Gruev, Viktor

    2010-12-06

    An analysis of the temporal noise in the Stokes parameters computed by division of focal plane polarimeters is presented. Theoretical estimations of the Stokes parameter signal-to-noise ratios for CCD polarization imaging sensors with both 4-polarizer and 2-polarizer micropolarization filter arrays are derived. The theoretical derivation is verified with measurements from an integrated polarization imaging sensor composed of a CCD imaging array and aluminum nanowire polarization filters. The measured data obtained from the CCD polarimeters matches the theoretical derivations of the temporal noise model of the Stokes parameters.

  10. Analyzing the data from X-ray polarimeters with Stokes parameters

    NASA Astrophysics Data System (ADS)

    Kislat, F.; Clark, B.; Beilicke, M.; Krawczynski, H.

    2015-08-01

    X-ray polarimetry promises to deliver unique information about the geometry of the inner accretion flow of astrophysical black holes and the nature of matter and electromagnetism in and around neutron stars. In this paper, we discuss the possibility to use Stokes parameters - a commonly used tool in radio, infrared, and optical polarimetry - to analyze the data from X-ray polarimeters such as scattering polarimeters and photoelectric effect polarimeters, which measure the linear polarization of the detected X-rays. Based on the azimuthal scattering angle (in the case of a scattering polarimeter) or the azimuthal component of the angle of the electron ejection (in the case of a photoelectric effect polarimeter), the Stokes parameters can be calculated for each event recorded in the detector. Owing to the additive nature of Stokes parameters, the analysis reduces to adding the Stokes parameters of the individual events and subtracting the Stokes parameters characterizing the background (if present). The main strength of this kind of analysis is that the errors on the Stokes parameters can be computed easily and are well behaved - in stark contrast of the errors on the polarization fraction and polarization direction. We demonstrate the power of the Stokes analysis by deriving several useful formulae, e.g. the expected error on the polarization fraction and polarization direction for a detection of NS signal and NBG background events, the optimal observation times of the signal and background regions in the presence of non-negligible background contamination of the signal, and the minimum detectable polarization (MDP) that can be achieved when following this prescription.

  11. Noise equalization in Stokes parameter images obtained by use of variable-retardance polarimeters.

    PubMed

    Tyo, J S

    2000-08-15

    An imaging variable retardance polarimeter was developed and tested by Tyo and Turner [Proc. SPIE 3753, 214 (1999)]. The signal-to-noise ratio (SNR) in the reconstructed polarization images obtained with this system varied for the four Stokes parameters. The difference in SNR is determined to be due to differences in the Euclidean lengths of the rows of the synthesis matrix used to reconstruct the Stokes parameters from the measured intensity data. I equalize (and minimize) the lengths of the rows of this matrix by minimizing the condition number of the synthesis matrix, thereby maximizing the relative importance of each of the polarimeter measurements. The performance of the optimized system is demonstrated with simulated data, and the SNR is shown to increase from a worst case of -3.1 dB for the original settings to a worst case of +5.0 dB for the optimized system.

  12. Single-shot spatially modulated Stokes polarimeter based on a GRIN lens.

    PubMed

    Chang, Jintao; Zeng, Nan; He, Honghui; He, Yonghong; Ma, Hui

    2014-05-01

    A new polarimeter for the simultaneous measurement of all Stokes parameters in a single shot is presented. It consists of only a gradient index (GRIN) lens, a polarizer, an imaging lens, and a CCD, without mechanical movements, electrical signal modulation, or the division of amplitude components. This design takes advantage of the continuous spatial distributions of birefringence value and the fast axis direction of a GRIN lens and derives the state of polarization (SOP) of the incident beam from the characteristic patterns on the CCD images. Tests show that this polarimeter is very accurate even with low-resolution images. It is versatile and adapts to light sources of different wavelengths. It is also very stable, robust, low cost, and simple to use.

  13. Optimal design and performance metric of broadband full-Stokes polarimeters with immunity to Poisson and Gaussian noise.

    PubMed

    Mu, Tingkui; Chen, Zeyu; Zhang, Chunmin; Liang, Rongguang

    2016-12-26

    In this paper, the design, optimization and analysis of broadband full-Stokes polarimeters with immunity to both Poisson and Gaussian noise are presented. Different from the commonly-used optimization metrics such as, the condition number (CN), the equally weighted variance (EWV), or the polarimetric modulation efficiency (PME) for Gaussian noise, the optimally balanced condition for Poisson noise (BCPN) is, for the first time, proposed and used as a metric for the optimization of polarimeters. The numerical results show that the polarimeters optimized with the BCPN have immunity to both Poisson and Gaussian noise. The broadband polarimeters optimized from the BCPN are achromatic and have similar polarimetric modulation properties over the waveband, in contrast to the polychromatic polarimeters optimized from the CN, EWV and PME, whose polarimetric modulation properties vary with wavelength.

  14. A high spatial resolution Stokes polarimeter for motional Stark effect imaging

    SciTech Connect

    Thorman, Alex; Michael, Clive; Howard, John

    2013-06-15

    We describe an enhanced temporally switched interfero-polarimeter that has been successfully deployed for high spatial resolution motional Stark effect imaging on the KSTAR superconducting tokamak. The system utilizes dual switching ferroelectric liquid crystal waveplates to image the full Stokes vector of elliptically polarized and Doppler-shifted Stark-Zeeman Balmer-alpha emission from high energy neutral beams injected into the magnetized plasma. We describe the optical system and compare its performance against a Mueller matrix model that takes account of non-ideal performance of the switching ferro-electric liquid crystal waveplates and other polarizing components.

  15. Innovative polarization-holographic imaging Stokes polarimeter for observational studies of the solar spicules: the first results

    NASA Astrophysics Data System (ADS)

    Kvernadze, Teimuraz; Kurkhuli, George; Kakauridze, George; Kilosanidze, Barbara; Kulijanishvili, Vazha; Khutsishvili, Eldar; Khutsishvili, David

    2017-01-01

    We present an innovative polarization-holographic imaging Stokes polarimeter based on a polarization-holographic diffraction element which enables the complete real time analysis of the polarization state of an incoming light. An element, recorded in a laboratory by a special holographic schema using circularly and linearly polarized beams, decomposes an incoming light into diffraction orders the intensities of which vary depending on the polarization state of a light source. After the CCD intensity measurements of the corresponding points or areas in the diffraction orders and further data reduction through the calibration parameters we get the real-time Stokes images of a light source or spectral line profiles which allows to determine full polarization state of a point or extended space object in narrow or wide spectral range. The operating spectral range of the polarimeter is 500-1600 nm with diffraction efficiency equal to 20% at 532 nm, 16% at 635 nm and 2% at 1550 nm. The theoretical model of relations between measured intensities in different diffraction orders and Stokes parameters, developed by the authors (Kilosanidze B., Kakauridze G. SPIE Proceedings, vol. 8082-126, 2011), were used to calibrate the polarimeter. The laboratory tests show that the resulting errors are near of 1% or better. First observations of the solar spicules show the ability of the proposed polarimeter to measure the joint Hanle and Zeeman effects. The polarimeter is compact, light weight and could be installed both on ground-based or airborne telescopes.

  16. In-band OSNR monitor with high-speed integrated Stokes polarimeter for polarization division multiplexed signal.

    PubMed

    Saida, Takashi; Ogawa, Ikuo; Mizuno, Takayuki; Sano, Kimikazu; Fukuyama, Hiroyuki; Muramoto, Yoshifumi; Hashizume, Yasuaki; Nosaka, Hideyuki; Yamamoto, Shuto; Murata, Koichi

    2012-12-10

    An in-band optical signal-to-noise ratio (OSNR) monitor is proposed, based on an instantaneous polarization state distribution analysis. The proposed monitor is simple, and is applicable to polarization division multiplexed signals. We fabricate a high-speed Stokes polarimeter that integrates a planar lightwave circuit (PLC) based polarization filter, high-speed InP/InGaAs photodiodes and InP hetero-junction bipolar transistor (HBT) trans-impedance amplifiers (TIA). We carry out proof-of-concept experiments with the fabricated polarimeter, and successfully measure the OSNR dependent polarization distribution with 100-Gb/s dual polarization quadrature phase shift keying (DP-QPSK) signals.

  17. Out-of-plane Stokes imaging polarimeter for early skin cancer diagnosis

    NASA Astrophysics Data System (ADS)

    Ghassemi, Pejhman; Lemaillet, Paul; Germer, Thomas A.; Shupp, Jeffrey W.; Venna, Suraj S.; Boisvert, Marc E.; Flanagan, Katherine E.; Jordan, Marion H.; Ramella-Roman, Jessica C.

    2012-07-01

    Optimal treatment of skin cancer before it metastasizes critically depends on early diagnosis and treatment. Imaging spectroscopy and polarized remittance have been utilized in the past for diagnostic purposes, but valuable information can be also obtained from the analysis of skin roughness. For this purpose, we have developed an out-of-plane hemispherical Stokes imaging polarimeter designed to monitor potential skin neoplasia based on a roughness assessment of the epidermis. The system was utilized to study the rough surface scattering for wax samples and human skin. The scattering by rough skin--simulating phantoms showed behavior that is reasonably described by a facet scattering model. Clinical tests were conducted on patients grouped as follows: benign nevi, melanocytic nevus, melanoma, and normal skin. Images were captured and analyzed, and polarization properties are presented in terms of the principal angle of the polarization ellipse and the degree of polarization. In the former case, there is separation between different groups of patients for some incidence azimuth angles. In the latter, separation between different skin samples for various incidence azimuth angles is observed.

  18. Development and manufacturing of panoramic Stokes polarimeter using the polarization films in the Main Astronomical Observatory of NAS of Ukraine

    NASA Astrophysics Data System (ADS)

    Vidmachenko, A. P.; Ivanov, Yu. S.; Syniavskyi, I. I.; Sergeev, A. V.

    2015-08-01

    In the Main Astronomical Observatory of NAS of Ukraine is proposed and implemented the concept of the imaging Stokes polarimeter [1-5]. This device allows carrying out measurements of the four Stokes vector components at the same time, in a wide field, and without any restrictions on the relative aperture of the optical system. Its scheme is developed so that only by turning wheel with replaceable elements, photopolarimeter could be transformed into a low resolution spectropolarimeter. The device has four film's polarizers with positional angles 0°, 45°, 90°, 135°. The device uses a system of special deflecting prisms in each channel. These prisms were achromatizing in the spectral range of 420-850 nm [2], the distortion of the polarimeter optical system is less than 0.65%. In manufacturing version of spectropolarimeter provided for the possibility of using working on passing the diffraction grating with a frequency up to 100 lines/mm. Has begun the laboratory testing of instrument. References. 1. Sinyavskii I.I., Ivanov Yu. S., Vidmachenko Anatoliy P., Karpov N.V. Panoramic Stokes-polarimeter // Ecological bulettin of research centers of the Black Sea Economic Cooperation. - 2013. - V. 3, No 4. - P. 123-127. 2. Sinyavskii I. I., Ivanov Yu. S., Vil'machenko A. P. Concept of the construction, of the optical setup of a panoramic Stokes polarimeter for small telescopes // Journal of Optical Technology. - 2013. - V. 80, Issue 9. - P. 545-548. 3. Vidmachenko A. P., Ivanov Yu. S., Morozhenko A. V., Nevodovsky E. P., Syniavskyi I. I., Sosonkin M. G. Spectropolarimeter of ground-based accompanying for the space experiment "Planetary Monitoring" // Kosmichna Nauka i Tekhnologiya. - 2007. - V. 13, No. 1, p. 63 - 70. 4. Yatskiv Ya. S., Vidmachenko A. P., Morozhenko A. V., Sosonkin M. G., Ivanov Yu. S., Syniavskyi I. I. Spectropolarimetric device for overatmospheric investigations of Solar System bodies // Kosmichna Nauka i Tekhnologiya. - 2008. - V. 14, No. 2. - P. 56

  19. Demonstration of a snapshot full-Stokes division-of-aperture imaging polarimeter using Wollaston prism array

    NASA Astrophysics Data System (ADS)

    Mu, Tingkui; Zhang, Chunmin; Liang, Rongguang

    2015-12-01

    A snapshot full-Stokes division-of-aperture imaging polarimeter using a Wollaston prism array (WPA) is theoretically described and experimentally demonstrated. Two-dimensional spatial distributions of six polarization eigenstates, linear (0°, 90°, 45°, 135°), and left and right circular polarization states, are identified and separated by the WPA simultaneously and projected onto the six portions of a single focal-plane array by a lens array. The conditions of the measurement matrix formed by the six polarization modulation channels are naturally superior for immunity to Gaussian and Poisson noise. The unique properties of the WPA, such as its high extinction ratio, optical efficiency and transmittance, can further ensure the achievement of immunity. The snapshot principle and the conditions of the measurement matrix are discussed. A proof-of-concept system using a complementary metal oxide semiconductor (CMOS) sensor for visible light is built and validated using laboratory and outdoor measurements.

  20. Target detection with a liquid-crystal-based passive Stokes polarimeter.

    PubMed

    Goudail, François; Terrier, Patrick; Takakura, Yoshitate; Bigué, Laurent; Galland, Frédéric; DeVlaminck, Vincent

    2004-01-10

    We present an imaging system that measures the polarimetric state of the light coming from each point of a scene. This system, which determines the four components of the Stokes vector at each spatial location, is based on a liquid-crystal polarization modulator, which makes it possible to acquire four-dimensional Stokes parameter images at a standard video rate. We show that using such polarimetric images instead of simple intensity images can improve target detection and segmentation performance.

  1. Advanced ACTPol Multichroic Polarimeter Array Fabrication Process for 150 mm Wafers

    NASA Technical Reports Server (NTRS)

    Duff, S. M.; Austermann, J.; Beall, J. A.; Becker, D.; Datta, R.; Gallardo, P. A.; Henderson, S. W.; Hilton, G. C.; Ho, S. P.; Hubmayr, J.; Koopman, B. J.; Li, D.; McMahon, J.; Nati, F.; Niemack, M. D.; Pappas, C. G.; Salatino, M.; Schmitt, B. L.; Simon, S. M.; Staggs, S. T.; Stevens, J. R.; Van Lanen, J.; Vavagiakis, E. M.; Ward, J. T.; Wollack, E. J.

    2016-01-01

    Advanced ACTPol (AdvACT) is a third-generation cosmic microwave background receiver to be deployed in 2016 on the Atacama Cosmology Telescope (ACT). Spanning five frequency bands from 25 to 280 GHz and having just over 5600 transition-edge sensor (TES) bolometers, this receiver will exhibit increased sensitivity and mapping speed compared to previously fielded ACT instruments. This paper presents the fabrication processes developed by NIST to scale to large arrays of feedhorn-coupled multichroic AlMn-based TES polarimeters on 150-mm diameter wafers. In addition to describing the streamlined fabrication process which enables high yields of densely packed detectors across larger wafers, we report the details of process improvements for sensor (AlMn) and insulator (SiN(sub x)) materials and microwave structures, and the resulting performance improvements.

  2. Advanced ACTPol Multichroic Polarimeter Array Fabrication Process for 150 mm Wafers

    NASA Astrophysics Data System (ADS)

    Duff, S. M.; Austermann, J.; Beall, J. A.; Becker, D.; Datta, R.; Gallardo, P. A.; Henderson, S. W.; Hilton, G. C.; Ho, S. P.; Hubmayr, J.; Koopman, B. J.; Li, D.; McMahon, J.; Nati, F.; Niemack, M. D.; Pappas, C. G.; Salatino, M.; Schmitt, B. L.; Simon, S. M.; Staggs, S. T.; Stevens, J. R.; Van Lanen, J.; Vavagiakis, E. M.; Ward, J. T.; Wollack, E. J.

    2016-08-01

    Advanced ACTPol (AdvACT) is a third-generation cosmic microwave background receiver to be deployed in 2016 on the Atacama Cosmology Telescope (ACT). Spanning five frequency bands from 25 to 280 GHz and having just over 5600 transition-edge sensor (TES) bolometers, this receiver will exhibit increased sensitivity and mapping speed compared to previously fielded ACT instruments. This paper presents the fabrication processes developed by NIST to scale to large arrays of feedhorn-coupled multichroic AlMn-based TES polarimeters on 150-mm diameter wafers. In addition to describing the streamlined fabrication process which enables high yields of densely packed detectors across larger wafers, we report the details of process improvements for sensor (AlMn) and insulator (SiN_x) materials and microwave structures, and the resulting performance improvements.

  3. Snapshot polarimeter fundus camera.

    PubMed

    DeHoog, Edward; Luo, Haitao; Oka, Kazuhiko; Dereniak, Eustace; Schwiegerling, James

    2009-03-20

    A snapshot imaging polarimeter utilizing Savart plates is integrated into a fundus camera for retinal imaging. Acquired retinal images can be processed to reconstruct Stokes vector images, giving insight into the polarization properties of the retina. Results for images from a normal healthy retina and retinas with pathology are examined and compared.

  4. Novel Pixilated Polarimeter and Associated Nanoimprinting Techniques, to Address Advanced Imaging Applications

    DTIC Science & Technology

    2007-06-15

    STATEMENT A: UNLIMITED AFRL-SR-AR-TR-080 169 13. SUPPLEMENTARY NOTES 14. ABSTRACT The final objective of this contract is to improve nano -optical sub...components and then further to demonstrate a monolithically integrated nano -optical pixilated-array polarimeter. In parallel, part of the goal of this...project is also to develop a low-cost web-to-web nanoimprint system/method/process for more efficiently making low-cost nano -structured optical devices

  5. Optical layout and mechanical structure of polarimeter-interferometer system for Experimental Advanced Superconducting Tokamak

    SciTech Connect

    Zou, Z. Y.; Liu, H. Q. Jie, Y. X.; Wang, Z. X.; Shen, J. S.; An, Z. H.; Yang, Y.; Zeng, L.; Wei, X. C.; Li, G. S.; Zhu, X.; Ding, W. X.; Brower, D. L.; Lan, T.

    2014-11-15

    A Far-InfaRed (FIR) three-wave POlarimeter-INTerferometer (POINT) system for measurement current density profile and electron density profile is under development for the EAST tokamak. The FIR beams are transmitted from the laser room to the optical tower adjacent to EAST via ∼20 m overmoded dielectric waveguide and then divided into 5 horizontal chords. The optical arrangement was designed using ZEMAX, which provides information on the beam spot size and energy distribution throughout the optical system. ZEMAX calculations used to optimize the optical layout design are combined with the mechanical design from CATIA, providing a 3D visualization of the entire POINT system.

  6. Optical layout and mechanical structure of polarimeter-interferometer system for Experimental Advanced Superconducting Tokamaka)

    NASA Astrophysics Data System (ADS)

    Zou, Z. Y.; Liu, H. Q.; Jie, Y. X.; Ding, W. X.; Brower, D. L.; Wang, Z. X.; Shen, J. S.; An, Z. H.; Yang, Y.; Zeng, L.; Wei, X. C.; Li, G. S.; Zhu, X.; Lan, T.

    2014-11-01

    A Far-InfaRed (FIR) three-wave POlarimeter-INTerferometer (POINT) system for measurement current density profile and electron density profile is under development for the EAST tokamak. The FIR beams are transmitted from the laser room to the optical tower adjacent to EAST via ˜20 m overmoded dielectric waveguide and then divided into 5 horizontal chords. The optical arrangement was designed using ZEMAX, which provides information on the beam spot size and energy distribution throughout the optical system. ZEMAX calculations used to optimize the optical layout design are combined with the mechanical design from CATIA, providing a 3D visualization of the entire POINT system.

  7. Optical layout and mechanical structure of polarimeter-interferometer system for Experimental Advanced Superconducting Tokamak.

    PubMed

    Zou, Z Y; Liu, H Q; Jie, Y X; Ding, W X; Brower, D L; Wang, Z X; Shen, J S; An, Z H; Yang, Y; Zeng, L; Wei, X C; Li, G S; Zhu, X; Lan, T

    2014-11-01

    A Far-InfaRed (FIR) three-wave POlarimeter-INTerferometer (POINT) system for measurement current density profile and electron density profile is under development for the EAST tokamak. The FIR beams are transmitted from the laser room to the optical tower adjacent to EAST via ∼20 m overmoded dielectric waveguide and then divided into 5 horizontal chords. The optical arrangement was designed using ZEMAX, which provides information on the beam spot size and energy distribution throughout the optical system. ZEMAX calculations used to optimize the optical layout design are combined with the mechanical design from CATIA, providing a 3D visualization of the entire POINT system.

  8. Astrobiological polarimeter

    NASA Astrophysics Data System (ADS)

    Kothari, Neeraj; Jafarpour, Aliakbar; Thaler, Tracey L.; Trebino, Rick; Bommarius, Andreas S.

    2007-09-01

    Chirality is an excellent indicator of life, but naturally occurring terrestrial and extra-terrestrial samples nearly always exhibit massive depolarizing light scattering (DLS). This problem bears a striking resemblance to that of developing a chirality-based non-invasive glucose monitor for diabetics. Both applications require a lightweight, compact, efficient, and robust polarimeter that can operate despite significant DLS. So for astrobiological applications, we developed a polarimeter that was inspired from a polarimetry technique previously investigated for non-invasive in-vivo glucose-sensing. Our polarimeter involves continuously rotating the plane of linear polarization of a laser beam to probe a sample with DLS, and analyzing its transmission with a fixed analyzer to obtain a sinusoidal voltage signal. We lock-in detect this signal using a reference signal from an analogous set up without any sample. With milk as a scatterer, we find that this polarimeter detects chirality in the presence of three orders of magnitude more DLS than conventional polarimeters. It can accurately measure 0.1° of polarization rotation in the presence of 15% milk.

  9. Maximum bandwidth snapshot channeled imaging polarimeter with polarization gratings

    NASA Astrophysics Data System (ADS)

    LaCasse, Charles F.; Redman, Brian J.; Kudenov, Michael W.; Craven, Julia M.

    2016-05-01

    Compact snapshot imaging polarimeters have been demonstrated in literature to provide Stokes parameter estimations for spatially varying scenes using polarization gratings. However, the demonstrated system does not employ aggressive modulation frequencies to take full advantage of the bandwidth available to the focal plane array. A snapshot imaging Stokes polarimeter is described and demonstrated through results. The simulation studies the challenges of using a maximum bandwidth configuration for a snapshot polarization grating based polarimeter, such as the fringe contrast attenuation that results from higher modulation frequencies. Similar simulation results are generated and compared for a microgrid polarimeter. Microgrid polarimeters are instruments where pixelated polarizers are superimposed onto a focal plan array, and this is another type of spatially modulated polarimeter, and the most common design uses a 2x2 super pixel of polarizers which maximally uses the available bandwidth of the focal plane array.

  10. DoFP polarimeter based polarization microscope for biomedical applications

    NASA Astrophysics Data System (ADS)

    Chang, Jintao; He, Honghui; He, Chao; Ma, Hui

    2016-03-01

    Polarization microscope is a useful technique to observe the optical anisotropic nature of biomedical specimens and provide more microstructural information than the conventional microscope. In this paper, we present a division of focal plane (DoFP) polarimeter based polarization microscope which is capable of imaging both the Stokes vector and the 3×4 Mueller matrix. The Mueller matrix measurement can help us completely understand the polarization properties of the sample and the Stokes vector measurement is a simultaneous technology. First, we calibrate a DoFP polarimeter using the polarization data reduction method for accurate Stokes vector measurements. Second, as the Stokes vector computation for all pixels using the calibrated instrument matrix is usually time consuming, we develop a GPU acceleration algorithm for real time Stokes vector calculations. Third, based on the accurate and fast Stokes vector calculation, we present an optimal 4-states of polarization (4-SoP) illumination scheme for Mueller matrix measurement using the DoFP polarimeter. Finally, we demonstrate the biomedical applications of the DoFP polarimeter based polarization microscope. Experiment results show that the characteristic features of many biomedical samples can be observed in the "polarization staining" images using the circularly polarized light as illumination. In this way, combined with GPU acceleration algorithm, the DoFP polarization microscope has the capacity for real time polarization monitoring of dynamic processes in biological samples.

  11. LEP and CEBAF polarimeters: Revision

    SciTech Connect

    Burkert, V.; Rossmanith, R.; Placidi, M.

    1988-01-01

    This paper gives an overview on high energy electron (positron) polarimeters by describing in more detail the plans for the LEP polarimeter and the CEBAF polarimeters. Both LEP and CEBAF will have laser polarimeters. In addition CEBAF will be equipped with a M/o/ller polarimeter (for currents below 1..mu..A). 4 refs., 10 figs.

  12. Chromospheric LAyer SpectroPolarimeter (CLASP2)

    NASA Astrophysics Data System (ADS)

    Narukage, Noriyuki; McKenzie, David E.; Ishikawa, Ryoko; Trujillo-Bueno, Javier; De Pontieu, Bart; Kubo, Masahito; Ishikawa, Shin-nosuke; Kano, Ryouhei; Suematsu, Yoshinori; Yoshida, Masaki; Rachmeler, Laurel A.; Kobayashi, Ken; Cirtain, Jonathan W.; Winebarger, Amy R.; Asensio Ramos, Andres; del Pino Aleman, Tanausu; Štępán, Jiri; Belluzzi, Luca; Larruquert, Juan Ignacio; Auchère, Frédéric; Leenaarts, Jorrit; Carlsson, Mattias J. L.

    2016-07-01

    The sounding rocket Chromospheric Lyman-Alpha SpectroPolarimeter (CLASP) was launched on September 3rd, 2015, and successfully detected (with a polarization accuracy of 0.1 %) the linear polarization signals (Stokes Q and U) that scattering processes were predicted to produce in the hydrogen Lyman-alpha line (Lyα 121.567 nm). Via the Hanle effect, this unique data set may provide novel information about the magnetic structure and energetics in the upper solar chromosphere. The CLASP instrument was safely recovered without any damage and we have recently proposed to dedicate its second flight to observe the four Stokes profiles in the spectral region of the Mg II h and k lines around 280 nm; in these lines the polarization signals result from scattering processes and the Hanle and Zeeman effects. Here we describe the modifications needed to develop this new instrument called the "Chromospheric LAyer SpectroPolarimeter" (CLASP2).

  13. A derivative standard for polarimeter calibration

    SciTech Connect

    Mulhollan, G.; Clendenin, J.; Saez, P.

    1996-10-01

    A long-standing problem in polarized electron physics is the lack of a traceable standard for calibrating electron spin polarimeters. While several polarimeters are absolutely calibrated to better than 2%, the typical instrument has an inherent accuracy no better than 10%. This variability among polarimeters makes it difficult to compare advances in polarized electron sources between laboratories. The authors have undertaken an effort to establish 100 nm thick molecular beam epitaxy grown GaAs(110) as a material which may be used as a derivative standard for calibrating systems possessing a solid state polarized electron source. The near-bandgap spin polarization of photoelectrons emitted from this material has been characterized for a variety of conditions and several laboratories which possess well calibrated polarimeters have measured the photoelectron polarization of cathodes cut from a common wafer. Despite instrumentation differences, the spread in the measurements is sufficiently small that this material may be used as a derivative calibration standard.

  14. LWIR Snapshot Imaging Polarimeter

    SciTech Connect

    Dr. Robert E Sampson

    2009-04-01

    This report describes the results of a phase 1 STTR to design a longwave infrared imaging polarimeter. The system design, expected performance and components needed to construct the imaging polarimeter are described. Expected performance is modeled and sytem specifications are presented.

  15. Models comparison for JET polarimeter data

    SciTech Connect

    Mazzotta, C.; Orsitto, F. P.; Giovannozzi, E.; Boboc, A.; Tudisco, O.; Zabeo, L.; Brombin, M.; Murari, A.

    2008-03-12

    A complete comparison between the theory and the measurements in polarimetry was done by using the Far Infrared Polarimeter at JET. More than 300 shots were analyzed, including a wide spectrum of JET scenarios in all critical conditions for polarimetry: high density, high and very low fields, high temperatures.This work is aimed at the demonstration of the robustness of the theoretical models for the JET polarimeter measurements in the perspective of using these models for ITER like plasma scenarios . In this context, an assessment was performed on how the line-integrated plasma density along the central vertical chord of FIR polarimeter could be evaluated using the Cotton-Mouton effect and its possible concrete use to correct fringe jumps of the interferometer.The models considered are: i) the rigorous numerical solution of the Stokes propagation equations, using dielectric tensor evaluated from JET equilibrium and Thomson scattering [1,2]; ii) two types of approximated solutions [2,3] and iii) the Guenther empirical model [4] that considers the mutual effect between Cotton-Mouton and Faraday rotation angle. The model calculations have been compared with polarimeter measurements for the Cotton-Mouton phase shift.The agreement with theory is satisfactory within the limits of experimental errors [3].

  16. Earth Observing Scanning Polarimeter (EOSP), phase B

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Evaluations performed during a Phase B study directed towards defining an optimal design for the Earth Observing Scanning Polarimeter (EOSP) instrument is summarized. An overview of the experiment approach is included which provides a summary of the scientific objectives, the background of the measurement approach, and the measurement method. In the instrumentation section, details of the design are discussed starting with the key instrument features required to accomplish the scientific objectives and a system characterization in terms of the Stokes vector/Mueller matrix formalism. This is followed by a detailing of the instrument design concept, the design of the individual elements of the system, the predicted performance, and a summary of appropriate instrument testing and calibration. The selected design makes use of key features of predecessor polarimeters and is fully compatible with the Earth Observing System spacecraft requirements.

  17. Snapshot polarimeter based on the conical refraction phenomenon

    NASA Astrophysics Data System (ADS)

    Peinado, Alba; Lizana, Angel; Turpin, Alex; Estévez, Irene; Iemmi, Claudio; Kalkanjiev, Todor K.; Mompart, Jordi; Campos, Juan

    2015-06-01

    A complete and punctual Stokes polarimeter based on the conical refraction (CR) phenomenon is presented. The CR phenomenon occurs when light travels along one of the optical axes of a biaxial crystal (BC), leading to a bright ring of light at the focal plane of the system. We propose using the connection between the intensity pattern of the CR ring and the state of polarization (SOP) of the incident beam as a new tool for polarization metrology. In order to implement a complete polarimeter, the instrument is designed with a beam splitter and two BCs, one BC for each sub-beam. In the second sub-beam, a retarder is introduced before the BC, allowing us to measure the ellipticity content of the input SOP. The CR-based polarimeter presents several appealing features compared to standard polarimeters. To name some of them, CR polarimeters retrieve the SOP of an input beam with a single snapshot measurement, allow for substantially enhancing the data redundancy without increasing measuring time, and avoid instrumental errors related to rotating elements or active polarization devices. This work shows the instrument design, in particular the parameters of the set-up have been optimized in order to reduce the amplification of noise. Then, the experimental implementation of the instrument is detailed, including the experimental calibration of the system. Finally, the implemented polarimeter is experimentally tested by measuring different SOPs, including fully and partially polarized light.

  18. Portable Imaging Polarimeter and Imaging Experiments

    SciTech Connect

    PHIPPS,GARY S.; KEMME,SHANALYN A.; SWEATT,WILLIAM C.; DESCOUR,M.R.; GARCIA,J.P.; DERENIAK,E.L.

    1999-11-01

    Polarimetry is the method of recording the state of polarization of light. Imaging polarimetry extends this method to recording the spatially resolved state of polarization within a scene. Imaging-polarimetry data have the potential to improve the detection of manmade objects in natural backgrounds. We have constructed a midwave infrared complete imaging polarimeter consisting of a fixed wire-grid polarizer and rotating form-birefringent retarder. The retardance and the orientation angles of the retarder were optimized to minimize the sensitivity of the instrument to noise in the measurements. The optimal retardance was found to be 132{degree} rather than the typical 90{degree}. The complete imaging polarimeter utilized a liquid-nitrogen cooled PtSi camera. The fixed wire-grid polarizer was located at the cold stop inside the camera dewar. The complete imaging polarimeter was operated in the 4.42-5 {micro}m spectral range. A series of imaging experiments was performed using as targets a surface of water, an automobile, and an aircraft. Further analysis of the polarization measurements revealed that in all three cases the magnitude of circular polarization was comparable to the noise in the calculated Stokes-vector components.

  19. A far infrared polarimeter

    NASA Astrophysics Data System (ADS)

    Catalano, A.; Conversi, L.; De Gregori, S.; De Petris, M.; Lamagna, L.; Maoli, R.; Savini, G.; Battistelli, E. S.; Orlando, A.

    2004-12-01

    We describe an experiment to measure calibration sources, the polarization of Cosmic Microwave Background Radiation (CMBR) and the polarization induced on the CMBR from S-Z effects, using a polarimeter, MITOPol, that will be employed at the MITO telescope. Two modulation methods are presented and compared: an amplitude modulation with a Fresnel double rhomb and a phase modulation with a modified Martin-Puplett interferometer. A first light is presented from the campaign (summer 2003) that has permitted to estimate the instrument spurious polarization using the second modulation method.

  20. High acceptance recoil polarimeter

    SciTech Connect

    The HARP Collaboration

    1992-12-05

    In order to detect neutrons and protons in the 50 to 600 MeV energy range and measure their polarization, an efficient, low-noise, self-calibrating device is being designed. This detector, known as the High Acceptance Recoil Polarimeter (HARP), is based on the recoil principle of proton detection from np[r arrow]n[prime]p[prime] or pp[r arrow]p[prime]p[prime] scattering (detected particles are underlined) which intrinsically yields polarization information on the incoming particle. HARP will be commissioned to carry out experiments in 1994.

  1. Full Stokes polarization imaging camera

    NASA Astrophysics Data System (ADS)

    Vedel, M.; Breugnot, S.; Lechocinski, N.

    2011-10-01

    Objective and background: We present a new version of Bossa Nova Technologies' passive polarization imaging camera. The previous version was performing live measurement of the Linear Stokes parameters (S0, S1, S2), and its derivatives. This new version presented in this paper performs live measurement of Full Stokes parameters, i.e. including the fourth parameter S3 related to the amount of circular polarization. Dedicated software was developed to provide live images of any Stokes related parameters such as the Degree Of Linear Polarization (DOLP), the Degree Of Circular Polarization (DOCP), the Angle Of Polarization (AOP). Results: We first we give a brief description of the camera and its technology. It is a Division Of Time Polarimeter using a custom ferroelectric liquid crystal cell. A description of the method used to calculate Data Reduction Matrix (DRM)5,9 linking intensity measurements and the Stokes parameters is given. The calibration was developed in order to maximize the condition number of the DRM. It also allows very efficient post processing of the images acquired. Complete evaluation of the precision of standard polarization parameters is described. We further present the standard features of the dedicated software that was developed to operate the camera. It provides live images of the Stokes vector components and the usual associated parameters. Finally some tests already conducted are presented. It includes indoor laboratory and outdoor measurements. This new camera will be a useful tool for many applications such as biomedical, remote sensing, metrology, material studies, and others.

  2. Snapshot imaging polarimeters using spatial modulation

    NASA Astrophysics Data System (ADS)

    Luo, Haitao

    The recent demonstration of a novel snapshot imaging polarimeter using the fringe modulation technique shows a promise in building a compact and moving-parts-free device. As just demonstrated in principle, this technique has not been adequately studied. In the effort of advancing this technique, we build a complete theory framework that can address the key issues regarding the polarization aberrations caused by using the functional elements. With this model, we can have the necessary knowledge in designing, analyzing and optimizing the systems. Also, we propose a broader technique that uses arbitrary modulation instead of sinusoidal fringes, which can give us more engineering freedom and can be the solution of achromatizing the system. In the hardware aspect, several important progresses are made. We extend the polarimeter technique from visible to middle wavelength infrared by using the yttrium vanadate crystals. Also, we incorporate a Savart Plate polarimter into a fundus camera to measure the human eye's retinal retardance, useful information for glaucoma diagnosis. Thirdly, a world-smallest imaging polarimeter is proposed and demonstrated, which may open many applications in security, remote sensing and bioscience.

  3. Advanced adaptive computational methods for Navier-Stokes simulations in rotorcraft aerodynamics

    NASA Technical Reports Server (NTRS)

    Stowers, S. T.; Bass, J. M.; Oden, J. T.

    1993-01-01

    A phase 2 research and development effort was conducted in area transonic, compressible, inviscid flows with an ultimate goal of numerically modeling complex flows inherent in advanced helicopter blade designs. The algorithms and methodologies therefore are classified as adaptive methods, which are error estimation techniques for approximating the local numerical error, and automatically refine or unrefine the mesh so as to deliver a given level of accuracy. The result is a scheme which attempts to produce the best possible results with the least number of grid points, degrees of freedom, and operations. These types of schemes automatically locate and resolve shocks, shear layers, and other flow details to an accuracy level specified by the user of the code. The phase 1 work involved a feasibility study of h-adaptive methods for steady viscous flows, with emphasis on accurate simulation of vortex initiation, migration, and interaction. Phase 2 effort focused on extending these algorithms and methodologies to a three-dimensional topology.

  4. Solving Navier-Stokes Equations with Advanced Turbulence Models on Three-Dimensional Unstructured Grids

    NASA Technical Reports Server (NTRS)

    Wang, Qun-Zhen; Massey, Steven J.; Abdol-Hamid, Khaled S.; Frink, Neal T.

    1999-01-01

    USM3D is a widely-used unstructured flow solver for simulating inviscid and viscous flows over complex geometries. The current version (version 5.0) of USM3D, however, does not have advanced turbulence models to accurately simulate complicated flows. We have implemented two modified versions of the original Jones and Launder k-epsilon two-equation turbulence model and the Girimaji algebraic Reynolds stress model in USM3D. Tests have been conducted for two flat plate boundary layer cases, a RAE2822 airfoil and an ONERA M6 wing. The results are compared with those of empirical formulae, theoretical results and the existing Spalart-Allmaras one-equation model.

  5. Experimental validation of optimum input polarization states for Mueller matrix determination with a dual photoelastic modulator polarimeter.

    PubMed

    Gribble, Adam; Layden, David; Vitkin, I Alex

    2013-12-15

    Dual photoelastic modulator polarimeters can measure light polarization, which is often described as a Stokes vector. By evaluating changes in polarization when light interacts with a sample, the sample Mueller matrix also can be derived, completely describing its interaction with polarized light. The choice of which and how many input Stokes vectors to use for sample investigation is under the experimenter's control. Previous work has predicted that sets of input Stokes vectors forming the vertices of platonic solids on the Poincaré sphere allow for the most robust Mueller matrix determination. Further, when errors specific to the dual photoelastic modulator polarimeter are considered, simulations revealed that one specific shape and orientation of Stokes vectors (cube on the Poincaré sphere with vertices away from principal sphere axes) allows for the most robust Mueller matrix determination. Here we experimentally validate the optimum input Stokes vectors for dual photoelastic modulator Mueller polarimetry, toward developing a robust polarimetric platform of increasing relevance to biophotonics.

  6. GRETINA as a Compton Polarimeter

    NASA Astrophysics Data System (ADS)

    Bender, P. C.; Weisshaar, D.; Gade, A.; Wiens, A.; Macchiavelli, A. O.; Campbell, C. M.; Clark, R. M.; Crawford, H. L.; Cromaz, M.; Fallon, P.; Lee, I. Y.; Rissanen, J.; Tabor, S. L.; Tripathi, V.; Albers, M.; Ayangeakaa, A. D.; Carpenter, M. P.; David, H. M.; Lauritsen, T.; Zhu, S.; Chowdhury, P.; Lister, C. J.; Merchan, E.; Prasher, V. S.; Miller, D.

    2016-09-01

    Characterization of GRETINA as a polarimeter using the tracking technique has been done by examing the gamma-rays emitted from polarized states following the 24Mg(p,p') reaction. Here we consider GRETINA as a traditional Compton polarimeter, where the intensity of the scattered radiation measured between physical detecting elements is used to determine its polarization sensitivity using techniques developed over the past decades. This provides a direct basic measure of the linear polarization of the array independent of the signal-decomposition and tracking algorithms, and directly comparable to traditional Compton polarimeters. The performance of GRETINA as a traditional Compton-polarimeter will be presented. This material is based upon work supported by the U.S. Department of Energy, Office of Science and Office of Nuclear Physics under Contracts Number DE-AC02-05CH11231(LBNL) and Number DE-AC02-06CH11357(ANL).

  7. Infrared hyperspectral imaging polarimeter using birefringent prisms.

    PubMed

    Craven-Jones, Julia; Kudenov, Michael W; Stapelbroek, Maryn G; Dereniak, Eustace L

    2011-03-10

    A compact short-wavelength and middle-wavelength infrared hyperspectral imaging polarimeter (IHIP) is introduced. The sensor includes a pair of sapphire Wollaston prisms and several high-order retarders to form an imaging Fourier transform spectropolarimeter. The Wollaston prisms serve as a birefringent interferometer with reduced sensitivity to vibration versus an unequal path interferometer, such as a Michelson. Polarimetric data are acquired through the use of channeled spectropolarimetry to modulate the spectrum with the Stokes parameter information. The collected interferogram is Fourier filtered and reconstructed to recover the spatially and spectrally varying Stokes vector data across the image. The IHIP operates over a ±5° field of view and implements a dual-scan false signature reduction technique to suppress polarimetric aliasing artifacts. In this paper, the optical layout and operation of the IHIP sensor are presented in addition to the radiometric, spectral, and polarimetric calibration techniques used with the system. Spectral and spectropolarimetric results from the laboratory and outdoor tests with the instrument are also presented.

  8. Polarimeter with two ferroelectric liquid-crystal modulators attached to the Yunnan solar tower.

    PubMed

    Xu, Chenglin; Qu, Zhongquan; Zhang, Xiaoyu; Jin, Chunlan; Yan, Xiaoli

    2006-11-20

    A polarimeter to be mounted on the Yunnan solar tower is described. It features the ability to simultaneously measure the magnetic fields of the solar photosphere and chromosphere by analyzing the Stokes spectra of those magnetosensitive lines forming in the two regions with very high efficiency of polarization measurement. The polarimeter consists of two ferroelectric liquid crystals and one lambda/4 wave plate before a polarizing beam splitter. The achromatism of the design is emphasized to get the maximum combination efficiency over a spectral range from 5000 to 6000 A. For the used solar absorption lines MgI517.27, FeI525.06, FeI630.15, and FeI630.25 nm, the design gives theoretical efficiencies of polarization measurements, which are 0.999, 1.0, 0.943, and 0.943, respectively. A comparison with other reference polarimeters, such as the Synoptic Optical Long-term Investigation of the Sun, the Tenerife infrared polarimeter, and the La Palma Stokes Polarimeter, is carried out.

  9. Design study of the PEPSI polarimeter for the LBT

    NASA Astrophysics Data System (ADS)

    Hofmann, A.; Strassmeier, K. G.; Woche, M.

    2002-07-01

    We present the conceptual design of the two polarimetric channels of the PEPSI spectropolarimeter for the Large Binocular Telescope (LBT). The two direct Gregorian f/15 focii of the LBT will take up two identical but independent full-Stokes IQUV polarimeters that themselves fiberfeed a high-resolution Echelle spectrograph (see the accompanying paper by Zerbi et al.). The polarizing units will be based on super-achromatic Fresnel-rhomb retarders and Foster prisms. A total of four fibers are foreseen to simultaneously direct two ordinary and two extraordinary light beams to the Echelle spectrograph. Both polarimetric units are layed out in a modular design, each one optimized to the polarization state in which it is used. A number of observing modes can be chosen that are optimized to the type of polarization that is expected from the target, e.g. circularly and linearly polarized light simultaneously, or linearly polarized light in both polarimeters, or integral light from one and polarized light from the other telescope, a.s.o.. Calibration would be provided for each polarimeter separately.

  10. KVI Lamb-shift polarimeter

    SciTech Connect

    Beijers, J.P.M.; Kremers, H.R.; Kalantar-Nayestanaki, N.

    2006-03-15

    The design and operation of a Lamb-shift polarimeter is discussed. This polarimeter is used to measure the polarization of proton and deuteron beams extracted from the KVI polarized-ion source. The major components of the Lamb-shift polarimeter (LSP) are described in some detail. These include the deceleration lens system, cesium neutralization oven, spin filter, metastable-atom detection system, and the solenoid. Typical operating parameters of the LSP will be given together with some representative spin-polarization measurements. The design criterion of measuring the polarization of a H{sup +} or D{sup +} beam within 60 s and with a statistical uncertainty smaller than 2% has been met.

  11. Design of the Polarimeter for the Fibre Arrayed Solar Optical Telescope

    NASA Astrophysics Data System (ADS)

    Dun, Guang-tao; Qu, Zhong-quan

    2013-01-01

    The theoretical design of the polarimeter used for the Fibre Arrayed Solar Optical Telescope (FASOT) is described. It has the following characteris- tics: (1) It is provided with the function of optical polarization switching, which makes the high-effciency polarimetry possible; (2) In the waveband of 750 nm, the polarimetric effciency is higher than 50% for the every Stokes parameter, and higher than 86.6% for the total polarization, thus an observer can make the simultaneous polarization measurements on multiple magnetosensitive lines in such a broad range of wavelength; (3) According to the selected photospheric and chromospheric lines, the measurement can be focused on either linear polarization or circular polarization; (4) The polarimeter has a loose tolerance on the manufacturing technology of polarimetric elements and installation errors. All this makes this polarimeter become a high-performance polarimetric device.

  12. Earth observing scanning polarimeter

    NASA Technical Reports Server (NTRS)

    Travis, Larry

    1993-01-01

    Climate forcing by tropospheric aerosols is receiving increased attention because of the realization that the climate effects may be large, while our knowledge of global aerosol characteristics and temporal changes is very poor. Tropospheric aerosols cause a direct radiative forcing due simply to their scattering and absorption of solar radiation, as well as an indirect effect as cloud condensation nuclei which can modify the shortwave reflectivity of clouds. Sulfate aerosols tend to increase planetary albedo through both the direct and indirect effects; a cooling due to anthropogenic sulfate aerosols has been estimated of order 1 W/sq m, noting that this is similar in magnitude to the present anthropogenic greenhouse gas warming. Other aerosols, including those from biomass burning and wind-blown desert dust are also of potential climatic importance. At present, the only global monitoring of tropospheric aerosols is a NOAA operational product, aerosol optical thickness, obtained using channel-1 (0.58-0.68 mu m) radiances from the AVHRR. With this single channel radiance data, one must use an approach which is based on the inferred excess of reflected radiance owing to scattering by the aerosols over that expected from theoretical calculations. This approach is suited only for situations where the surface has a low albedo that is well known a priori. Thus, the NOAA operational product is restricted to coverage over the ocean at AVHRR scan angles well away from sun glint, and aerosol changes are subject to confusion with changes caused by either optically thin or subpixel clouds. Because optically thin aerosols have only a small effect on the radiance, accurate measurements for optical thickness less than 0.1 (which is a typical background level) are precluded. Moreover, some of the largest and most important aerosol changes are expected over land. The Earth Observing Scanning Polarimeter (EOSP) instrument, based upon design heritage and analysis techniques

  13. POET: POlarimeters for Energetic Transients

    NASA Technical Reports Server (NTRS)

    Hill, J. E.; McConnell, M. L.; Bloser, P.; Legere, J.; Macri, J.; Ryan, J.; Barthelmy, S.; Angelini, L.; Sakamoto, T.; Black, J. K.; Hartmann, D. H.; Kaaret, P.; Zhang, B.; Ioka, K.; Nakamura, T.; Toma, K.; Yamazaki, R.; Wu, X.

    2008-01-01

    POET (Polarimeters for Energetic Transients) is a Small Explorer mission concept proposed to NASA in January 2008. The principal scientific goal of POET is to measure GRB polarization between 2 and 500 keV. The payload consists of two wide FoV instruments: a Low Energy Polarimeter (LEP) capable of polarization measurements in the energy range from 2-15 keV and a high energy polarimeter (Gamma-Ray Polarimeter Experiment - GRAPE) that will measure polarization in the 60-500 keV energy range. Spectra will be measured from 2 keV up to 1 MeV. The POET spacecraft provides a zenith-pointed platform for maximizing the exposure to deep space. Spacecraft rotation will provide a means of effectively dealing with systematics in the polarization response. POET will provide sufficient sensitivity and sky coverage to measure statistically significant polarization for up to 100 GRBs in a two-year mission. Polarization data will also be obtained for solar flares, pulsars and other sources of astronomical interest.

  14. A Si Integrated Waveguiding Polarimeter

    NASA Astrophysics Data System (ADS)

    Kevorkian, A. P.

    1987-09-01

    The technology and characteristics of a silicon-based polarimeter are presented. This device features guided mode polarization splitting, non-taper solution for guided light detection and electronic signal processing. The overall fabrication process is fully compatible with standard Si technology.

  15. Total elimination of sampling errors in polarization imagery obtained with integrated microgrid polarimeters.

    PubMed

    Tyo, J Scott; LaCasse, Charles F; Ratliff, Bradley M

    2009-10-15

    Microgrid polarimeters operate by integrating a focal plane array with an array of micropolarizers. The Stokes parameters are estimated by comparing polarization measurements from pixels in a neighborhood around the point of interest. The main drawback is that the measurements used to estimate the Stokes vector are made at different locations, leading to a false polarization signature owing to instantaneous field-of-view (IFOV) errors. We demonstrate for the first time, to our knowledge, that spatially band limited polarization images can be ideally reconstructed with no IFOV error by using a linear system framework.

  16. Full-order Mueller matrix polarimeter using liquid-crystal phase retarders and active illumination

    NASA Astrophysics Data System (ADS)

    Dayton, David C.; Hoover, Brian G.; Gonglewski, John D.

    2003-03-01

    Full order Stokes polarimeters are often composed of an analyzer consisting of a rotating quarter wave plate in front of a horizontal polarizer. A number of measurements are then made with the wave-plate oriented at different angle. The four-element Stokes vector is then computed from a linear combination of these measurements. A disadvantage of this device is that only a limited range of analyzer states can be generated. As a result a large number of measurements may be required to reduce the noise gain in the Stokes vector reconstructor. In this paper we describe a polarimeter based on a linear polarizer and two variable wave plates. It can be shown that such a device can produce an arbitrary polarization state. An active polarimeter consists of a generator stage, which transmits a laser illuminator with different polarization states and a receiver with a polarization analyzer stage. In our system both generator and analyzer stages consist of a horizontal polarizer and two variable wave-plates. A sixteen element Mueller matrix of resolved images is then formed for target characterization.

  17. Hyperspectral imaging polarimeter design and calibration

    NASA Astrophysics Data System (ADS)

    Loe, Richard S.; Duggin, Michael J.

    2002-01-01

    The integration and calibration of a hyperspectral imaging polarimeter is described. The system was designed to exploit subtle spectral details in visible and near-IR hyperspectral polarimetric images. All of the system components were commercial-off-the-shelf. This device uses a tunable liquid crystal filter and 16-bit cooled CCD camera. The challenges of calibrating a hyperspectral polarimeter are discussed.

  18. Interpolation strategies for reducing IFOV artifacts in microgrid polarimeter imagery.

    PubMed

    Ratliff, Bradley M; LaCasse, Charles F; Tyo, J Scott

    2009-05-25

    Microgrid polarimeters are composed of an array of micro-polarizing elements overlaid upon an FPA sensor. In the past decade systems have been designed and built in all regions of the optical spectrum. These systems have rugged, compact designs and the ability to obtain a complete set of polarimetric measurements during a single image capture. However, these systems acquire the polarization measurements through spatial modulation and each measurement has a varying instantaneous field-of-view (IFOV). When these measurements are combined to estimate the polarization images, strong edge artifacts are present that severely degrade the estimated polarization imagery. These artifacts can be reduced when interpolation strategies are first applied to the intensity data prior to Stokes vector estimation. Here we formally study IFOV error and the performance of several bilinear interpolation strategies used for reducing it.

  19. The polarimeters for HARPS and X-shooter

    NASA Astrophysics Data System (ADS)

    Snik, F.; Harpspol Team; X-Shooter-Pol Team

    2013-01-01

    Spectropolarimetry enables observations of stellar magnetic fields and circumstellar asymmetries, e.g. in disks and supernova explosions. To furnish better diagnostics of such stellar physics, we designed and commissioned a polarimetric unit at the successful HARPS spectrograph at ESO's 3.6-m telescope at La Silla. We present the design and performance of HARPSpol, and show some first science results. The most striking achievement of HARPSpol is its capability to measure stellar magnetic fields as small as 0.1 G. Finally, we give a sneak preview of the polarimeter we are currently designing for X-shooter at the VLT. It contains a novel type of polarimetric modulator that is able to efficiently measure all the Stokes parameters over the huge wavelength range of 300-2500 nm.

  20. MeV Science with the Advanced Energetic Pair Telescope (AdEPT), a High Sensitivity Medium-Energy Gamma-Ray Polarimeter

    NASA Astrophysics Data System (ADS)

    Venters, Tonia M.; Hunter, Stanley D.; De Nolfo, Georgia; Hanu, Andrei R.; Krizmanic, John F.; Stecker, Floyd W.; Timokhin, Andrey

    2016-04-01

    Many high-energy astrophysical phenomena exhibit unique, transitory behavior, such as spectral breaks, bursts, and flares below ~200 MeV. However, while significant progress in gamma-rays has been made by instruments such as Fermi and AGILE, a significant sensitivity gap remains in the medium-energy regime (0.75 - 200 MeV) that has been explored only by COMPTEL and EGRET on CGRO. Tapping into this unexplored regime requires development of a telescope with significant improvement in sensitivity. Our mission concept, covering ~5 to ~200 MeV, is the Advanced Energetic Pair Telescope (AdEPT). The AdEPT telescope will achieve angular resolution of ~0.6 deg at 70 MeV, similar to the angular resolution of Fermi/LAT at ~1 GeV that brought tremendous success in identifying new sources. AdEPT will also provide unprecedented polarization sensitivity, ~1% for a 1 Crab source. The enabling technology for AdEPT is the Three-Dimensional Track Imager (3-DTI) a low-density, large volume, gas time-projection chamber with a 2-dimensional readout. The 3-DTI provides high-resolution three-dimensional electron tracking with minimal Coulomb scattering that is essential to achieve high angular resolution and polarization sensitivity. We describe the design, fabrication, and performance of the 3-DTI detector, describe the development of a 50x50x100 cm3 AdEPT prototype, and highlight a few of the key science questions that AdEPT will address.

  1. Compact inline optical electron polarimeter.

    PubMed

    Pirbhai, M; Ryan, D M; Richards, G; Gay, T J

    2013-05-01

    A compact optical electron polarimeter using a helium target is described. It offers a maximum fluorescence detection efficiency of ~20 Hz/nA, which is an order of magnitude higher than that of earlier designs. With an argon target, this device is expected to have a polarimetric figure-of-merit of 270 Hz/nA. By relying on a magnetic field to guide a longitudinally spin-polarized electron beam, the present instrument employs fewer electrodes. It also uses a commercially available integrated photon counting module. These features allow it to occupy a smaller volume and make it easier to operate.

  2. Applications of the INPOL polarimeter

    NASA Astrophysics Data System (ADS)

    Palarczyk, M.; Rapaport, J.; Hicks, K.; Huatala, C.; Yang, X.; Prout, D. L.; Anderson, B.; Baldwin, A.; Madey, R.; Manley, D.; Watson, J.; Zhang, W.; Suleiman, R.; Ahmidouch, A.; Khayat, M.; Foster, C. C.; Goodman, C. D.; Savopulos, G.; Sowinski, J.; Luther, B. A.; Taddeucci, T. N.; Cooper, D. A.; Sugarbaker, E.; Niculescu, I.; Carr, R.; Howes, R.; Islam, M. S.; Ober, D.; Perera, N.; Sages, H.; Thomas, G.; West, J.; van Heerden, I.

    1996-10-01

    The INPOL polarimeter moved from LAMPF, upgraded and placed in operation at IUCF, measures polarization transfer parameters (D_ij) up to 200 MeV incident proton energy with an effective analyzing power (A_eff) of about 30%. Also, due to the large flight path and under good beam conditions, it can be a useful device to measure transitions to weak and difficult to isolate states, such as low lying states in ^127Xe. The determination of σB(GT) for the 124 keV transition is of great interest for the Homestake Iodine Solar Neutrino Detector. Results will be presented from recent experiments.

  3. An imaging spectro-polarimeter for measuring hemispherical spectrally resolved down-welling sky polarization

    NASA Astrophysics Data System (ADS)

    Chenault, David B.; Pezzaniti, J. L.; Roche, Michael; Hyatt, Brian

    2016-05-01

    A full sky imaging spectro-polarimeter has been developed that measures spectrally resolved (~2.5 nm resolution) radiance and polarization (𝑠0, 𝑠1, 𝑠2 Stokes Elements) of natural sky down-welling over approximately 2π sr between 400nm and 1000nm. The sensor is based on a scanning push broom hyperspectral imager configured with a continuously rotating polarizer (sequential measurement in time polarimeter). Sensor control and processing software (based on Polaris Sensor Technologies Grave' camera control software) has a straight-forward and intuitive user interface that provides real-time updated sky down-welling spectral radiance/polarization maps and statistical analysis tools.

  4. The Absolute Spectrum Polarimeter (ASP)

    NASA Technical Reports Server (NTRS)

    Kogut, A. J.

    2010-01-01

    The Absolute Spectrum Polarimeter (ASP) is an Explorer-class mission to map the absolute intensity and linear polarization of the cosmic microwave background and diffuse astrophysical foregrounds over the full sky from 30 GHz to 5 THz. The principal science goal is the detection and characterization of linear polarization from an inflationary epoch in the early universe, with tensor-to-scalar ratio r much greater than 1O(raised to the power of { -3}) and Compton distortion y < 10 (raised to the power of{-6}). We describe the ASP instrument and mission architecture needed to detect the signature of an inflationary epoch in the early universe using only 4 semiconductor bolometers.

  5. Polarization modulation polarimeter for an HPLC detector

    NASA Astrophysics Data System (ADS)

    Shindo, Yohji; Yazawa, Masanori; Izuka, Mituharu; Aoyama, Hideki; Kinnbara, Masao; Maeda, Shiro

    1997-04-01

    A polarization modulation polarimeter for a HPLC detector has been designed and constructed based on a principle, the electrical null-point detection method, which is entirely different from that of a commercially available polarimeters, the optical null-point detection method. The Mueller matrix method is used to analyze and evaluate important factors determining its performance. It is revealed that a crystal quartz Rochon prism must be used as a polarizer, and should be mounted on a rotatable stage equipped with a mechanism for precise adjustment to set its azimuth angle at 0 degrees as precisely as possible. Furthermore, all optical components used should have the least amount of the residual static birefringence. The total performance of our polarimeter is found to be equivalent to that of commercially available polarimeters.

  6. Note: A portable rotating waveplate polarimeter

    NASA Astrophysics Data System (ADS)

    Bobach, Søren; Hidic, Adnan; Arlt, Jan J.; Hilliard, Andrew J.

    2017-03-01

    We describe the construction and performance of a polarimeter based on a quarter-wave plate rotated by a model airplane motor. The motor rotates at a high angular frequency of ω ˜2 π ×160 Hz, which enables the polarimeter to monitor the polarization state of an incident beam of light in real-time. We show that a simple analysis of the polarimeter signal using the fast Fourier transform on a standard digital oscilloscope provides an excellent measure of the polarization state for many laboratory applications. The polarimeter is straightforward to construct, portable, and features a high-dynamic range, facilitating a wide range of optics laboratory tasks that require free-space or fiber-based polarization analysis.

  7. LWIR Microgrid Polarimeter for Remote Sensing Studies

    DTIC Science & Technology

    2010-02-28

    Polarimeter for Remote Sensing Studies 5b. GRANT NUMBER FA9550-08-1-0295 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 1. Scott Tyo 5e. TASK...and tested at the University of Arizona, and preliminary images are shown in this final report. 15. SUBJECT TERMS Remote Sensing , polarimetry 16...7.0 LWIR Microgrid Polarimeter for Remote Sensing Studies J. Scott Tyo College of Optical Sciences University of Arizona Tucson, AZ, 85721 tyo

  8. Polarimeter for the General Fusion SPECTOR machine

    NASA Astrophysics Data System (ADS)

    Carle, Patrick; Froese, Aaron; Wong, Adrian; Howard, Stephen; O'Shea, Peter; Laberge, Michel

    2016-11-01

    A polarimeter has been designed to measure Faraday rotation and help to understand the profile of its safety factor, q, on the recently built SPECTOR magnetized target fusion machine at General Fusion. The polarimeter uses two counter-rotating, circularly polarized, 118.8 μm beams to probe the plasma. Grad-Shafranov simulations have been used to investigate the effect of measurement error and chord geometry.

  9. Albany/FELIX: a parallel, scalable and robust, finite element, first-order Stokes approximation ice sheet solver built for advanced analysis

    NASA Astrophysics Data System (ADS)

    Tezaur, I. K.; Perego, M.; Salinger, A. G.; Tuminaro, R. S.; Price, S. F.

    2015-04-01

    This paper describes a new parallel, scalable and robust finite element based solver for the first-order Stokes momentum balance equations for ice flow. The solver, known as Albany/FELIX, is constructed using the component-based approach to building application codes, in which mature, modular libraries developed as a part of the Trilinos project are combined using abstract interfaces and template-based generic programming, resulting in a final code with access to dozens of algorithmic and advanced analysis capabilities. Following an overview of the relevant partial differential equations and boundary conditions, the numerical methods chosen to discretize the ice flow equations are described, along with their implementation. The results of several verification studies of the model accuracy are presented using (1) new test cases for simplified two-dimensional (2-D) versions of the governing equations derived using the method of manufactured solutions, and (2) canonical ice sheet modeling benchmarks. Model accuracy and convergence with respect to mesh resolution are then studied on problems involving a realistic Greenland ice sheet geometry discretized using hexahedral and tetrahedral meshes. Also explored as a part of this study is the effect of vertical mesh resolution on the solution accuracy and solver performance. The robustness and scalability of our solver on these problems is demonstrated. Lastly, we show that good scalability can be achieved by preconditioning the iterative linear solver using a new algebraic multilevel preconditioner, constructed based on the idea of semi-coarsening.

  10. Albany/FELIX: A parallel, scalable and robust, finite element, first-order Stokes approximation ice sheet solver built for advanced analysis

    SciTech Connect

    Tezaur, I. K.; Perego, M.; Salinger, A. G.; Tuminaro, R. S.; Price, S. F.

    2015-04-27

    This paper describes a new parallel, scalable and robust finite element based solver for the first-order Stokes momentum balance equations for ice flow. The solver, known as Albany/FELIX, is constructed using the component-based approach to building application codes, in which mature, modular libraries developed as a part of the Trilinos project are combined using abstract interfaces and template-based generic programming, resulting in a final code with access to dozens of algorithmic and advanced analysis capabilities. Following an overview of the relevant partial differential equations and boundary conditions, the numerical methods chosen to discretize the ice flow equations are described, along with their implementation. The results of several verification studies of the model accuracy are presented using (1) new test cases for simplified two-dimensional (2-D) versions of the governing equations derived using the method of manufactured solutions, and (2) canonical ice sheet modeling benchmarks. Model accuracy and convergence with respect to mesh resolution are then studied on problems involving a realistic Greenland ice sheet geometry discretized using hexahedral and tetrahedral meshes. Also explored as a part of this study is the effect of vertical mesh resolution on the solution accuracy and solver performance. The robustness and scalability of our solver on these problems is demonstrated. Lastly, we show that good scalability can be achieved by preconditioning the iterative linear solver using a new algebraic multilevel preconditioner, constructed based on the idea of semi-coarsening.

  11. Albany/FELIX: A parallel, scalable and robust, finite element, first-order Stokes approximation ice sheet solver built for advanced analysis

    DOE PAGES

    Tezaur, I. K.; Perego, M.; Salinger, A. G.; ...

    2015-04-27

    This paper describes a new parallel, scalable and robust finite element based solver for the first-order Stokes momentum balance equations for ice flow. The solver, known as Albany/FELIX, is constructed using the component-based approach to building application codes, in which mature, modular libraries developed as a part of the Trilinos project are combined using abstract interfaces and template-based generic programming, resulting in a final code with access to dozens of algorithmic and advanced analysis capabilities. Following an overview of the relevant partial differential equations and boundary conditions, the numerical methods chosen to discretize the ice flow equations are described, alongmore » with their implementation. The results of several verification studies of the model accuracy are presented using (1) new test cases for simplified two-dimensional (2-D) versions of the governing equations derived using the method of manufactured solutions, and (2) canonical ice sheet modeling benchmarks. Model accuracy and convergence with respect to mesh resolution are then studied on problems involving a realistic Greenland ice sheet geometry discretized using hexahedral and tetrahedral meshes. Also explored as a part of this study is the effect of vertical mesh resolution on the solution accuracy and solver performance. The robustness and scalability of our solver on these problems is demonstrated. Lastly, we show that good scalability can be achieved by preconditioning the iterative linear solver using a new algebraic multilevel preconditioner, constructed based on the idea of semi-coarsening.« less

  12. Turbulent Navier-Stokes Flow Analysis of an Advanced Semispan Diamond-Wing Model in Tunnel and Free Air at High-Lift Conditions

    NASA Technical Reports Server (NTRS)

    Ghaffari, Farhad; Biedron, Robert T.; Luckring, James M.

    2002-01-01

    Turbulent Navier-Stokes computational results are presented for an advanced diamond wing semispan model at low-speed, high-lift conditions. The numerical results are obtained in support of a wind-tunnel test that was conducted in the National Transonic Facility at the NASA Langley Research Center. The model incorporated a generic fuselage and was mounted on the tunnel sidewall using a constant-width non-metric standoff. The computations were performed at to a nominal approach and landing flow conditions.The computed high-lift flow characteristics for the model in both the tunnel and in free-air environment are presented. The computed wing pressure distributions agreed well with the measured data and they both indicated a small effect due to the tunnel wall interference effects. However, the wall interference effects were found to be relatively more pronounced in the measured and the computed lift, drag and pitching moment. Although the magnitudes of the computed forces and moment were slightly off compared to the measured data, the increments due the wall interference effects were predicted reasonably well. The numerical results are also presented on the combined effects of the tunnel sidewall boundary layer and the standoff geometry on the fuselage forebody pressure distributions and the resulting impact on the configuration longitudinal aerodynamic characteristics.

  13. GRASSP (GRAnada Sprite Spectrograph and Polarimeter). Design and implementation.

    NASA Astrophysics Data System (ADS)

    Passas, María; Sánchez, Justo; Gordillo-Vázquez, Francisco J.; Luque, Alejandro; Parra-Rojas, Francisco C.

    2013-04-01

    Transient luminous events (TLEs) are short optical emissions that occur in the upper atmosphere above storm systems. They appear between 15 and 90 km altitude and last between less than a millisecond to up to two seconds. So far there are no polarization studies of TLEs, nor high-resolution spectroscopy results which could help us to understand the kinetics and electrodynamics of these kind of optical emissions. The GRASSP (Granada Sprite Spectrograph and Polarimeter) instrument has been developed to measure simultaneously the polarization and the spectra of the light emitted from these TLEs with medium spectral resolution (0.45nm). By consulting a real-time lightning database, the telescope aims automatically to the region of the sky where a TLE is predicted to appear. The instrument is located outside the 2.2 m dome of the German-Spanish Astronomical Center at Calar Alto, Sierra de Los Filabres, north of Almería (Andalucía, Southern Spain), at 2168 meters above mean sea level. From this location we can observe the western Mediterranean Sea zone (37°-45°N; 2°W-6°E) with an elevation of 10°-35° above the horizon, a region where the most TLE activity in Europe takes place. GRASSP is a prototype which consists of a spectrograph and a polarimeter, both installed on a telescope mount. The 6-channel imaging polarimeter will cover a spectral range from 500 - 750 nm, with a polarized / unpolarized sensitivity smaller than 5 %. It will present a circular field of view of 5° and a CCD of 2000 × 2000 pixels with a FOV of 15 µm/px. The goal is to find the 4 Stokes parameters in a single shot. To do so, the polarimeter consists of seven circular windows disposed over a telescope surface, six of them are located around the border of the circle and the last one is located in the center. This single window will show the unfiltered image and the six remaining ones include a different polarizer ( 0° 45° 90° 180° linear polarizers and left and right circular

  14. A Burst Chasing X-ray Polarimeter

    NASA Technical Reports Server (NTRS)

    Hill, Joanne; Hill, Joe; Barthelmy, S.; Black, K.; Deines-Jones, P.; Jahoda, K.; Sakamoto, T.; Kaaret, P.; McConnell, M.; Bloser, P.; Macri, J.; Legere, J.; Ryan, J.; Smith, B., Jr.; Zhang, B.

    2007-01-01

    Tihs is a viewgraph presentation of a discussion of the X-ray Polarimeter. Gamma-ray bursts are one of the most powerful explosions in the universe and have been detected out to distances of almost 13 billion light years. The exact origin of these energetic explosions is still unknown but the resulting huge release of energy is thought to create a highly relativistic jet of material and a power-law distribution of electrons. There are several theories describing the origin of the prompt GRB emission that currently cannot be distinguished. Measurements of the linear polarization would provide unique and important constraints on the mechanisms thought to drive these powerful explosions. We present the design of a sensitive, and extremely versatile gamma-ray burst polarimeter. The instrument is a photoelectric polarimeter based on a time-projection chamber. The photoelectric time-projection technique combines high sensitivity with broad band-pass and is potentially the most powerful method between 2 and 100 keV where the photoelectric effect is the dominant interaction process We present measurements of polarized and unpolarized X-rays obtained with a prototype detector and describe the two mission concepts, the Gamma-Ray Burst Polarimeter (GRBP) for thc U S Naval Academy satellite MidSTAR-2, and thc Low Energy Polarimeter (LEP) onboard POET, a broadband polarimetry concept for a small explorer mission.

  15. A Simple Polarimeter and Experiments Utilizing an Overhead Projector.

    ERIC Educational Resources Information Center

    Dorn, H. C.; And Others

    1984-01-01

    Although polarimeters that illustrate rotation of plane-polarized light by chiral solutions have been previously described, the polarimeter described in this paper has certain advantages when used in conjunction with an overhead projector. Instructions for constructing this polarimeter and its use in demonstrating the optical activity of sugars…

  16. An integrated thermo-structural model to design a polarimeter for the GTC

    NASA Astrophysics Data System (ADS)

    Di Varano, I.; Strassmeier, K. G.; Woche, M.; Laux, U.

    2016-07-01

    The GTC (Gran Telescopio Canarias), with an equivalent aperture of 10.4 m, effective focal length of 169.9 m, located at the Observatorio del Roque de los Muchachos , in La Palma, Canary Islands, will host on its Cassegrain focus the GRAPE polarimeter (GRAntecan PolarimEter). At such focus the plate scale is 1.21 arcsec/mm and the unvignetted FOV 8 arcmin. The instrument will provide full Stokes polarimetry in the spectral range 380-1500 nm, feeding simultaneously up to two spectrographs. At the moment an interface to HORS (High Optical Resolution Spectrograph) is being defined, located on the Nasmyth platform, it has a FWHM resolving power of about 25,000 (5 pixel) within a spectral range of 400-680 nm. The rotator and instrumental flanges for the Cassegrain focus are currently under definition. Hereafter I present the state of art of the mechanical design of the polarimeter, whose strategy is based on an integrated model of Zemax design into ANSYS FEM static and dynamic analyses with thermal loads applied, in order to retrieve tip-tilt, decentering errors and other significant parameters to be looped back to the Zemax model. In such a way it is possible to compare and refine the results achieved through the tolerance analysis.

  17. A polarimeter for the high resolution ultraviolet spectrometer/polarimeter. [Solar Maximum Mission

    NASA Technical Reports Server (NTRS)

    Calvert, J. A.

    1980-01-01

    The design requirements of the polarimeter were established by the scientific optical objectives of the experiment to be launched aboard the Solar Max Mission which will study active solar regions. The polarization of the light is accomplished by a rotating magnesium fluoride quarter wave plate. The quarter wave plates are rotated in 22 1/2 degree steps about an axis coincidental with the light beam. As the light beam passes through the wave plate, the transformation that occurs can be expressed by mathematical equations. By having the wave plates calibrated, the data obtained from solar flares can be analyzed and meaningful information provided to the investigators. The polarimeter has two wave plates with different optical characteristics to provide both redundancy and versatility. A four mirror polarizer was added behind one wave plate to provide additional polarization. The mechanical design, testing, and operation of the polarimeter for the high resolution ultraviolet spectrometer/polarimeter are described.

  18. Rocket Experiment Demonstration of a Soft X-ray Polarimeter

    NASA Astrophysics Data System (ADS)

    Marshall, Herman

    This proposal is the lead proposal. Boston University will submit, via NSPIRES, a Co-I proposal, per instructions for Suborbital proposals for multiple-award. Our scientific goal of the Rocket Experiment Demonstration of a Soft X-ray Polarimeter (REDSoX Polarimeter) is to make the first measurement of the linear X-ray polarization of an extragalactic source in the 0.2-0.8 keV band. The first flight of the REDSoX Polarimeter would target Mk 421, which is commonly modeled as a highly relativistic jet aimed nearly along the line of sight. Such sources are likely to be polarized at a level of 30-60%, so the goal is to obtain a significant detection even if it is as low as 10%. Significant revisions to the models of jets emanating from black holes at the cores of active galaxies would be required if the polarization fraction lower than 10%. We employ multilayer-coated mirrors as Bragg reflectors at the Brewster angle. By matching to the dispersion of a spectrometer, one may take advantage of high multilayer reflectivities and achieve polarization modulation factors over 90%. Using replicated foil mirrors from MSFC and gratings made at MIT, we construct a spectrometer that disperses to three laterally graded multilayer mirrors (LGMLs). The lateral grading changes the wavelength of the Bragg peak for 45 degree reflections linearly across the mirror, matching the dispersion of the spectrometer. By dividing the entrance aperture into six equal sectors, pairs of blazed gratings from opposite sectors are oriented to disperse to the same LGML. The position angles for the LGMLs are 120 degrees to each other. CCD detectors then measure the intensities of the dispersed spectra after reflection and polarizing by the LGMLs, giving the three Stokes parameters needed to determine the source polarization. We will rely on components whose performance has been verified in the laboratory or in space. The CCD detectors are based on Chandra and Suzaku heritage. The mirror fabrication team

  19. Fast Solar Polarimeter: Prototype Characterization and First Results

    NASA Astrophysics Data System (ADS)

    Iglesias, F. A.; Feller, A.; Krishnappa, N.; Solanki, S. K.

    2016-04-01

    Due to the differential and non-simultaneous nature of polarization measurements, seeing induced crosstalk (SIC) and seeing limited spatial resolution can easily counterbalance the benefits of solar imaging polarimetry from the ground. The development of instrumental techniques to treat these issues is necessary to fully exploit the next generation of large-aperture solar facilities, and maintain ground-based data at a competitive level with respect to its space-based counterpart. In particular, considering that many open questions in modern solar physics demand data with challenging specifications of resolution and polarimetric sensitivity that can only be achieved with large telescope apertures (Stenflo 1999). Even if state-of-the-art adaptive optics systems greatly improve image quality, their limited correction —due to finite bandwidth, mode number and seeing anisoplanat- ism— produces large residual values of SIC (Krishnappa & Feller 2012). Dual beam polarimeters are commonly used to reduce SIC between the intensity and polarization signals, however, they cannot compensate for the SIC introduced between circular and linear polarization, which can be relevant for high-precision polarimetry. It is known that fast modulation effectively reduces SIC, but the demodulation of the corresponding intensity signals imposes hard requirements on the frame rate of the associated cameras. One way to avoid a fast sensor, is to decouple the camera readout from the intensity demodulation step. This concept is the cornerstone of the very successful Zurich Imaging Polarimeter (ZIMPOL). Even though the ZIMPOL solution allows the detection of very faint signals (˜10-5), its design is not suitable for high-spatial-resolution applications. We are developing a polarimeter that focuses on both spatial resolution (<0.5 arcsec) and polarimetric sensitivity (10-4). The prototype of this Fast Solar Polarimeter (FSP, see Feller et al. 2014), employs a high frame-rate (400 fps), low

  20. A Burst Chasing X-ray Polarimeter

    NASA Technical Reports Server (NTRS)

    Hill, Joanne E.; Barthelmy, Scott; Black, J. kevin; Deines-Jones, Philip; Jahoda, Keith; Sakamoto, Takanori; Kaaret, Philip; McConnell, Mark L.; Bloser, Peter F.; Macri, John R.; Legere, Jason S.; Ryan, James M.; Smith, Billy R., Jr.; Zhang, Bing

    2007-01-01

    Gamma-ray bursts are one of the most powerful explosions in the universe and have been detected out to distances of almost 13 billion light years. The exact origin of these energetic explosions is still unknown but the resulting huge release of energy is thought to create a highly relativistic jet of material and a power-law distribution of electrons. There are several theories describing the origin of the prompt GRB emission that currently cannot be distinguished. Measurements of the linear polarization would provide unique and important constraints on the mechanisms thought to drive these powerful explosions. We present the design of a sensitive, and extremely versatile gamma-ray burst polarimeter. The instrument is a photoelectric polarimeter based on a time-projection chamber. The photoelectric time-projection technique combines high sensitivity with broad band-pass and is potentially the most powerful method between 2 and 100 keV where the photoelectric effect 1s the dominant interaction process We present measurements of polarized and unpolarized X-rays obtained with a prototype detector and describe the two mission concepts, the Gamma-Ray Burst Polarimeter (GRBP) for thc U S Naval Academy satellite MidSTAR-2, and thc Low Energy Polarimeter (LEP) onboard POET, a broadband polarimetry concept for a small explorer mission.

  1. PoET: Polarimeters for Energetic Transients

    NASA Technical Reports Server (NTRS)

    McConnell, Mark; Barthelmy, Scott; Hill, Joanne

    2008-01-01

    This presentation focuses on PoET (Polarimeters for Energetic Transients): a Small Explorer mission concept proposed to NASA in January 2008. The principal scientific goal of POET is to measure GRB polarization between 2 and 500 keV. The payload consists of two wide FoV instruments: a Low Energy Polarimeter (LEP) capable of polarization measurements in the energy range from 2-15 keV and a high energy polarimeter (Gamma-Ray Polarimeter Experiment - GRAPE) that will measure polarization in the 60-500 keV energy range. Spectra will be measured from 2 keV up to 1 MeV. The PoET spacecraft provides a zenith-pointed platform for maximizing the exposure to deep space. Spacecraft rotation will provide a means of effectively dealing with systematics in the polarization response. PoET will provide sufficient sensitivity and sky coverage to measure statistically significant polarization for up to 100 GRBs in a two-year mission. Polarization data will also be obtained for solar flares, pulsars and other sources of astronomical interest.

  2. Imaging polarimeters for solar extreme ultraviolet astronomy

    NASA Technical Reports Server (NTRS)

    Hoover, Richard B.; Fineschi, Silvano; Fontenla, Juan M.; Walker, Arthur B. C., Jr.

    1991-01-01

    Accounts are given of EUV/FUV polarimetric instrument concepts for solar research which observe linear polarization in the spectral lines which originate in the outer solar atmosphere. The coronagraph/polarimeter instruments discussed employ all-reflective optical systems using ultrasmooth, low-scatter normal incidence mirrors and reflective polarization analyzers. The reflecting polarization analyzers operate at the Brewster angle.

  3. SPIDER: probing the early Universe with a suborbital polarimeter

    SciTech Connect

    Fraisse, A.A.; Chiang, H.C.; Ade, P.A.R.; Amiri, M.; Burger, B.; Davis, G.; Benton, S.J.; Bock, J.J.; Crill, B.P.; Doré, O.; Filippini, J.P.; Golwala, S.; Bond, J.R.; Farhang, M.; Bonetti, J.A.; Bryan, S.; Clark, C.N.; Contaldi, C.R.; Fissel, L.M.; Gandilo, N.N.; and others

    2013-04-01

    We evaluate the ability of SPIDER, a balloon-borne polarimeter, to detect a divergence-free polarization pattern (B-modes) in the cosmic microwave background (CMB). In the inflationary scenario, the amplitude of this signal is proportional to that of the primordial scalar perturbations through the tensor-to-scalar ratio r. We show that the expected level of systematic error in the SPIDER instrument is significantly below the amplitude of an interesting cosmological signal with r = 0.03. We present a scanning strategy that enables us to minimize uncertainty in the reconstruction of the Stokes parameters used to characterize the CMB, while accessing a relatively wide range of angular scales. Evaluating the amplitude of the polarized Galactic emission in the SPIDER field, we conclude that the polarized emission from interstellar dust is as bright or brighter than the cosmological signal at all SPIDER frequencies (90 GHz, 150 GHz, and 280 GHz), a situation similar to that found in the ''Southern Hole.'' We show that two ∼ 20-day flights of the SPIDER instrument can constrain the amplitude of the B-mode signal to r < 0.03 (99% CL) even when foreground contamination is taken into account. In the absence of foregrounds, the same limit can be reached after one 20-day flight.

  4. A comparison of Stokes parameters for sky and a soybean canopy

    NASA Technical Reports Server (NTRS)

    Schutt, John B.; Holben, Brent N.; Mcmurtrey, James E., III

    1991-01-01

    An evaluation of the polarization signatures obtained from the four Stokes parameters is reported for the atmosphere and a soybean canopy. The polarimeter design and operation are set forth, and the Stokes parameters' relationships are discussed. The canopy polarization was different from the sky at azimuths of 90 and 270 degrees, demonstrating a response that reflecting the sky polarization signatures across a plane parallel to the polarization axis and passing through a phase angle of about 90 degrees would produce. Classical behavior in terms of electromagnetic theory was found in the fourth Stokes parameter of the canopy which was obtained in the principal plane. Only the third Stokes parameter is demonstrated to be unambiguously affected in a comparison of sky polarization signatures and aerosol optical densities. The similarity between the sky at azimuth 180 degrees and the soybean canopy data at the principal plane is interesting considering the disparity of the subjects.

  5. Stokes Profile Analysis and Vector Magnetic Fields. VI. Fine Scale Structure of a Sunspot

    NASA Astrophysics Data System (ADS)

    Lites, B. W.; Elmore, D. F.; Seagraves, P.; Skumanich, A. P.

    1993-12-01

    The vector magnetic field structure of a small, symmetric sunspot observed very close to disk center has been explored using data from the High Altitude Observatory/National Solar Observatory Advanced Stokes Polarimeter (ASP). This instrument provides, for the first time, quantitative information on sunspot photospheric vector magnetic fields with high angular resolution, as derived from full Stokes profiles of the Zeeman-sensitive Fe I line pair at 630 nm. We find the following. (1) The penumbra contains narrow, radial "spines" of more intense magnetic field more vertically oriented than their surroundings; (2) the magnetic field diverges azimuthally away from the spine axes, as it should for a more intense intrusion of field embedded in a gravitational stratified atmosphere; (3) there are dark protrusions out from the umbra which traverse much of the penumbra and which are characterized by more vertical magnetic field; (4) the observed structure of the magnetic field in both the umbra and penumbra is stable over the 30 minute duration of our observing sequence; (5) we do not find a tight correlation of field inclination with intensity in the penumbra; (6) at the outer edge of the penumbra, the field penetrates the photosphere at an average angle of about 70° from the vertical; (7) outside of the penumbra the sunspot field forms a canopy which is directly observed by our technique; (8) outside of, but close to the sunspot, there are small magnetic features of mixed polarity that are rather highly inclined to the vertical, presumably as influenced by the sunspot canopy; (9) away from the sunspot, the isolated magnetic elements have nearly vertical orientation. These observations suggest that magnetic buoyancy, in addition to thermal buoyancy, plays an important role in maintaining the observed structure in sunspot penumbra.

  6. Snapshot retinal imaging Mueller matrix polarimeter

    NASA Astrophysics Data System (ADS)

    Wang, Yifan; Kudenov, Michael; Kashani, Amir; Schwiegerling, Jim; Escuti, Michael

    2015-09-01

    Early diagnosis of glaucoma, which is a leading cause for visual impairment, is critical for successful treatment. It has been shown that Imaging polarimetry has advantages in early detection of structural changes in the retina. Here, we theoretically and experimentally present a snapshot Mueller Matrix Polarimeter fundus camera, which has the potential to record the polarization-altering characteristics of retina with a single snapshot. It is made by incorporating polarization gratings into a fundus camera design. Complete Mueller Matrix data sets can be obtained by analyzing the polarization fringes projected onto the image plane. In this paper, we describe the experimental implementation of the snapshot retinal imaging Mueller matrix polarimeter (SRIMMP), highlight issues related to calibration, and provide preliminary images acquired from the camera.

  7. XUV polarimeter for undulator radiation measurements

    SciTech Connect

    Gluskin, E.; Mattson, J.E.; Bader, S.D.; Viccaro, P.J. ); Barbee, T.W. Jr. ); Brookes, N. ); Pitas, A. ); Watts, R. )

    1991-01-01

    A polarimeter for x-ray and vacuum ultraviolet (XUV) radiation was built to measure the spatial spectral dependence of the polarization of the light produced by the new undulator at the U5 beamline at NSLS. The fourth-harmonic radiation was measured, and it does not agree with predictions based on ideal simulation codes in the far-field approximation. 13 ref., 7 figs.

  8. GEMS X-ray Polarimeter Performance Simulations

    NASA Technical Reports Server (NTRS)

    Baumgartner, Wayne H.; Strohmayer, Tod; Kallman, Tim; Black, J. Kevin; Hill, Joanne; Swank, Jean

    2012-01-01

    The Gravity and Extreme Magnetism Small explorer (GEMS) is an X-ray polarization telescope selected as a NASA small explorer satellite mission. The X-ray Polarimeter on GEMS uses a Time Projection Chamber gas proportional counter to measure the polarization of astrophysical X-rays in the 2-10 keV band by sensing the direction of the track of the primary photoelectron excited by the incident X-ray. We have simulated the expected sensitivity of the polarimeter to polarized X-rays. We use the simulation package Penelope to model the physics of the interaction of the initial photoelectron with the detector gas and to determine the distribution of charge deposited in the detector volume. We then model the charge diffusion in the detector,and produce simulated track images. Within the track reconstruction algorithm we apply cuts on the track shape and focus on the initial photoelectron direction in order to maximize the overall sensitivity of the instrument, using this technique we have predicted instrument modulation factors nu(sub 100) for 100% polarized X-rays ranging from 10% to over 60% across the 2-10 keV X-ray band. We also discuss the simulation program used to develop and model some of the algorithms used for triggering, and energy measurement of events in the polarimeter.

  9. Fast Solar Polarimeter: First Light Results

    NASA Astrophysics Data System (ADS)

    Krishnappa, N.; Feller, A.; Iglesia, F. A.; Solanki, S.

    2013-12-01

    Accurate measurements of magnetic fields on the Sun are crucial to understand various physical processes that take place in the solar atmosphere such as solar eruptions, coronal heating, solar wind acceleration, etc. The Fast Solar Polarimeter (FSP) is a new instrument that is being developed to probe magnetic fields on the Sun. One of the main goals of this polarimeter is to carry out high precision spectropolarimetric observations with spatial resolution close to the telescope diffraction limit. The polarimeter is based on pnCCD technology with split frame transfer and simultaneous multi-channel readout, resulting in frame rate upto 1 kHz. The FSP prototype instrument uses a small format pnCCD of 264x264 pixels which has been developed by PNSensor and by the semiconductor lab of the Max Planck Society. The polarization modulator is based on two ferro-electric liquid crystals (FLCs) interlaced between two static retarders. The first solar observations have been carried out with this prototype during May-June, 2013 at German Vacuum Tower Telescope (VTT) on Tenerife, Canary Islands, Spain. Here we present the instrument performance assessments and the first results on the magnetic field measurements. Further, we briefly discuss about the next phase of FSP which will be a dual beam system with 1k x 1k CCDs.

  10. Thermal control modeling approach for GRAPE (GRAntecan PolarimEter)

    NASA Astrophysics Data System (ADS)

    Di Varano, I.; Woche, M.; Strassmeier, K. G.

    2016-08-01

    GRAPE is the polarimeter planned to be installed on the main Cassegrain focus of GTC (Gran Telescopio Canarias), having an equivalent entrance pupil of 10.4 m, located at the Observatorio del Roque de los Muchachos (ORM) , in La Palma, Canary Islands. It's meant to deliver full Stokes (IQUV) polarimetry covering the spectral range 0.420-1.6 μ, in order to feed the HORS instrument (High Optical Resolution Spectrograph), mounted on the Nasmyth platform, which has a FWHM resolving power of about 25,000 (5 pixel) designed for the wavelength range of 380-800 nm. Two calcite blocks and a BK-7 prism arranged in a Foster configuration are splitting the Ø12.5mm collimated beam into the ordinary and extraordinary components. The entire subunit from the Foster prisms down to the input fibers is rotated by steps of 45 degrees in order to retrieve Q, U components. By inserting a quarter wave retarder plate before the entrance to the Foster unit circular polarization is measured too. The current paper consist of two main parts: at first CFD simulations are introduced, which have been run compliant to the specifications derived by the environmental conditions and the transient thermal gradients taking into account the presence of the electronic cabinets installed, which are triggering the boundary conditions for the outer structure of the instrument; then a thermal control model is proposed based on heat exchangers to stabilize the inner temperature when compensation via passive insulation is not enough. The tools that have been adopted to reach for such goal are Ansys Multiphysics, in particular CFX package and Python scripts.

  11. Preliminary status of POLICAN: A near-infrared imaging polarimeter

    NASA Astrophysics Data System (ADS)

    Devaraj, R.; Luna, A.; Carrasco, L.; Mayya, Y. D.

    2015-10-01

    POLICAN is a near-infrared (J, H, K) imaging polarimeter developed for the Cananea near infrared camera (CANICA) at the 2.1m telescope of the Guillermo Haro Astrophysical Observatory (OAGH) located at Cananea, Sonora, México. The camera has a 1024 x 1024 HgCdTe detector (HAWAII array) with a plate scale of 0.32 arcsec/pixel providing a field of view of 5.5 x 5.5 arcmin. POLICAN is mounted externally to CANICA for narrow-field (f/12) linear polarimetric observations. It consists of a rotating super achromatic (1-2.7μm) half waveplate and a fixed wire-grid polarizer as the analyzer. The light is modulated by setting the half waveplate at different angles (0°, 22.5°, 45°, 67.5°) and linear combinations of the Stokes parameters (I, Q and U) are obtained. Image reduction and removal of instrumental polarization consist of dark noise subtraction, polarimetric flat fielding and background sky subtraction. Polarimetric calibration is performed by observing polarization standards available in the literature. The astrometry correction is performed by matching common stars with the Two Micron All Sky Survey. POLICAN's bright and limiting magnitudes are approximately 6th and 16th magnitude, which correspond to saturation and photon noise, respectively. POLICAN currently achieves a polarimetric accuracy about 3.0% and polarization angle uncertainties within 3°. Preliminary observations of star forming regions are being carried out in order to study their magnetic field properties.

  12. Imaging Spectropolarimeter for the Multi-Application Solar Telescope at Udaipur Solar Observatory: Characterization of Polarimeter and Preliminary Observations

    NASA Astrophysics Data System (ADS)

    Tiwary, Alok Ranjan; Mathew, Shibu K.; Bayanna, A. Raja; Venkatakrishnan, P.; Yadav, Rahul

    2017-04-01

    The Multi-Application Solar Telescope (MAST) is a 50 cm off-axis Gregorian telescope that has recently become operational at the Udaipur Solar Observatory (USO). An imaging spectropolarimeter is being developed as one of the back-end instruments of MAST to gain a better understanding of the evolution and dynamics of solar magnetic and velocity fields. This system consists of a narrow-band filter and a polarimeter. The polarimeter includes a linear polarizer and two sets of liquid crystal variable retarders (LCVRs). The instrument is intended for simultaneous observations in the spectral lines 6173 Å and 8542 Å, which are formed in the photosphere and chromosphere, respectively. In this article, we present results from the characterization of the LCVRs for the spectral lines of interest and the response matrix of the polarimeter. We also present preliminary observations of an active region obtained using the spectropolarimeter. For verification purposes, we compare the Stokes observations of the active region obtained from the Helioseismic Magnetic Imager (HMI) onboard the Solar Dynamics Observatory (SDO) with that of MAST observations in the spectral line 6173 Å. We find good agreement between the two observations, considering the fact that MAST observations are limited by seeing.

  13. Integration of a thermo-structural analysis with an optical model for PEPSI polarimeter

    NASA Astrophysics Data System (ADS)

    Di Varano, Igor; Strassmeier, Klaus G.; Ilyin, Ilya; Woche, Manfred; Kaercher, Hans J.

    2011-09-01

    The two spectropolarimeters for PEPSI (Potsdam Echelle Polarimetric and Spectroscopic Instrument) have been de¬signed in order to reconstruct the full Stokes vector measuring linear and circular polarization simultaneously with a re¬solving power of 120,000. The polarimeters will be attached to the Gregorian focus of the so far largest LBT 2x8.4m telescope and will feed together with permanent focus stations the spectrograph via 44m long fibers connection. The spectrograph will be located in a pressure-temperature controlled chamber within the telescope pier. We present hereafter the last results from combined structural and CFD analyses in order to fulfill the optical requirements.

  14. Active polarimeter optical system laser hazard analysis.

    SciTech Connect

    Augustoni, Arnold L.

    2005-07-01

    A laser hazard analysis was performed for the SNL Active Polarimeter Optical System based on the ANSI Standard Z136.1-2000, American National Standard for Safe Use of Lasers and the ANSI Standard Z136.6-2000, American National Standard for Safe Use of Lasers Outdoors. The Active Polarimeter Optical System (APOS) uses a pulsed, near-infrared, chromium doped lithium strontium aluminum fluoride (Cr:LiSAF) crystal laser in conjunction with a holographic diffuser and lens to illuminate a scene of interest. The APOS is intended for outdoor operations. The system is mounted on a height adjustable platform (6 feet to 40 feet) and sits atop a tripod that points the beam downward. The beam can be pointed from nadir to as much as 60 degrees off of nadir producing an illuminating spot geometry that can vary from circular (at nadir) to elliptical in shape (off of nadir). The JP Innovations crystal Cr:LiSAF laser parameters are presented in section II. The illuminating laser spot size is variable and can be adjusted by adjusting the separation distance between the lens and the holographic diffuser. The system is adjusted while platform is at the lowest level. The laser spot is adjusted for a particular spot size at a particular distance (elevation) from the laser by adjusting the separation distance (d{sub diffuser}) to predetermined values. The downward pointing angle is also adjusted before the platform is raised to the selected operation elevation.

  15. Design and Fabrication of the All-Reflecting H-Lyman alpha Coronagraph/Polarimeter

    NASA Technical Reports Server (NTRS)

    Hoover, Richard B.; Johnson, R. Barry; Fineschi, Silvano; Walker, Arthur B. C., Jr.; Baker, Phillip C.; Zukic , Muamer; Kim, Jongmin

    1993-01-01

    We have designed, analyzed, and are now fabricating an All-Reflecting H-Lyman alpha Coronagraph/Polarimeter for solar research. This new instrument operates in a narrow bandpass centered at lambda 1215.7 A-the neutral hydrogen Lyman alpha (Ly-alpha) line. It is shorter and faster than the telescope which produced solar Ly-alpha images as a part of the MSSTA payload that was launched on May 13, 1991. The Ly-alpha line is produced and linearly polarized in the solar corona by resonance scattering, and the presence of a magnetic field modifies this polarization according to the Hanle effect. The Lyman alpha Coronagraph/Polarimeter instrument has been designed to measure coronal magnetic fields by interpreting, via the Hanle effect, the measured linear polarization of the coronal Ly-alpha line. Ultrasmooth mirrors, polarizers, and filters are being flow-polished for this instrument from CVD silicon carbide substrates. These optical components will be coated using advanced induced transmission and absorption thin film multilayer coatings, to optimize the reflectivity and polarization properties at 1215.7 A. We describe some of the solar imaging results obtained with the MSSTA Lyman alpha coronagraph. We also discuss the optical design parameters and fabrication plans for the All-Reflecting H-Lyman alpha Coronagraph/Polarimeter.

  16. Extreme-ultraviolet polarimeter utilizing laser-generated high-order harmonics.

    PubMed

    Brimhall, Nicole; Turner, Matthew; Herrick, Nicholas; Allred, David D; Turley, R Steven; Ware, Michael; Peatross, Justin

    2008-10-01

    We describe an extreme-ultraviolet (EUV) polarimeter that employs laser-generated high-order harmonics as the light source. The polarimeter is designed to characterize materials and thin films for use with EUV light. Laser high harmonics are highly directional with easily rotatable linear polarization, not typically available with other EUV sources. The harmonics have good wavelength coverage, potentially spanning the entire EUV from a few to a hundred nanometers. Our instrument is configured to measure reflectances from 14 to 30 nm and has approximately 180 spectral resolution (lambda/Delta lambda). The reflection from a sample surface can be measured over a continuous range of incident angles (5 degrees-75 degrees). A secondary 14 cm gas cell attenuates the harmonics in a controlled way to keep signals within the linear dynamic range of the detector, comprised of a microchannel plate coupled to a phosphorous screen and charge coupled device camera. The harmonics are produced using approximately 10 mJ, approximately 35 fs, and approximately 800 nm laser pulses with a repetition rate of 10 Hz. Per-shot energy monitoring of the laser discriminates against fluctuations. The polarimeter reflectance data agree well with data obtained at the Advanced Light Source Synchrotron (Beamline 6.3.2).

  17. Induced Stokes or anti-Stokes nuclear transitions

    SciTech Connect

    Eliezer, S. |; Martinez-Val, J.M.; Velarde, G.

    1995-11-01

    It is suggested that laser-generated soft x rays can be used to induce Stokes or anti-Stokes nuclear transitions. Isomeric transitions in {sup 99}Tc and {sup 179}Hf are considered as Stokes and anti-Stokes transitions, respectively. It is shown that success of the proposed scheme may open the way for a gamma-ray laser. 18 refs., 2 figs.

  18. Spatial calibration of full stokes polarization imaging camera

    NASA Astrophysics Data System (ADS)

    Vedel, M.; Breugnot, S.; Lechocinski, N.

    2014-05-01

    Objective and background: We present a new method for the calibration of Bossa Nova Technologies' full Stokes, passive polarization imaging camera SALSA. The SALSA camera is a Division of Time Imaging Polarimeter. It uses custom made Ferroelectric Liquid Crystals mounted directly in front of the camera's CCD. Regular calibration process based on Data Reduction Matrix calculation assumes a perfect spatial uniformity of the FLC. However, alignment of FLC molecules can be disturbed by external constraints like mechanical stress from fixture, temperature variations and humidity. This disarray of the FLC molecules alignment appears as spatial non-uniformity. With typical DRM condition numbers of 2 to 5, the influence on DOLP and DOCP variations over the field of view can get up to 10%. Spatial nonuniformity of commercially available FLC products is the limiting factor for achieving reliable performances over the whole camera's field of view. We developed a field calibration technique based on mapping the CCD into areas of interest, then applying the DRM calculations on those individual areas. Results: First, we provide general background of the SALSA camera's technology, its performances and limitations. Detailed analysis of commercially available FLCs is described. Particularly, the spatial non uniformity influence on the Stokes parameters. Then, the new calibration technique is presented. Several configurations and parameters are tested: even division of the CCD into square-shaped regions, the number of regions, adaptive regions. Finally, the spatial DRM "stitching" process is described, especially for live calculation and display of Stokes parameters.

  19. Polarimeters for the AGS polarized-proton beam

    SciTech Connect

    Crabb, D.G.; Bonner, B.; Buchanan, J.

    1983-01-01

    This report describes the three polarimeters which will be used to measure the beam polarization at the AGS polarized beam facility. The beam polarization will be measured before injection into the AGS, during acceleration, and after extraction from the AGS. The 200-MeV polarimeter uses scintillation-counter telescopes to measure the asymmetry in p-carbon inclusive scattering. The internal polarimeter can measure the beam polarization at up to five selected times during acceleration. A continuously spooled nylon filament is swung into the beam at the appropriate time and the asymmetry in pp elastic scattering measured by two scintillation-counter telescopes. This is a relative polarimeter which can be calibrated by the absolute external polarimeter located in the D extracted-beam line. This polarimeter uses scintillation counters in two double-arm magnetic spectrometers to measure clearly the asymmetry in pp elastic scattering from a liquid hydrogen target. The specific features and operation of each polarimeter will be discussed.

  20. Silicon Stokes terahertz laser

    SciTech Connect

    Pavlov, S. G.; Huebers, H.-W.; Hovenier, J. N.; Klaassen, T. O.; Carder, D. A.; Phillips, P. J.; Redlich, B.; Riemann, H.; Zhukavin, R. Kh.; Shastin, V. N.

    2007-04-10

    A Raman-type silicon laser at terahertz frequencies has been realized. Stokes-shifted stimulated emission has been observed from silicon crystals doped by antimony donors when optically excited by an infrared free electron laser. The Raman lasing was obtained due to resonant scattering on electronic states of a donor atom.

  1. A hard X-ray polarimeter utilizing Compton scattering

    NASA Technical Reports Server (NTRS)

    Sakurai, H.; Noma, M.; Niizeki, H.

    1991-01-01

    The paper describes a 50-cm-diam prototype of a novel Compton-scattering-type polarimeter for hard X-rays in the energy range 30-100 keV. The characteristics of the prototype polarimeter were investigated for various conditions. It was found that, with polarized X-rays from a simple polarizer, the detection efficiency and the modulation factor of the polarimeter with a 40-mm thick scatterer were 3.2 percent and 0.57 percent, respectively, at about 60 keV.

  2. SPARO, the Submillimeter Polarimeter for Antarctic Remote Observing

    NASA Astrophysics Data System (ADS)

    Renbarger, T.; Chuss, D. T.; Novak, G.; Dotson, J. L.; Griffin, G.; Newcomb, M.; O'Brien, T. B.; Peterson, J. B.; Pernic, D.; Loewenstein, R. F.; Loverde, S.

    2000-12-01

    We report on a 9 pixel polarimeter, SPARO, the Submillimeter Polarimeter for Antarctic Remote Observing, for use on the Viper telescope, located at the Amundsen-Scott South Pole Station. We describe the design and performance of the polarimeter and highlight those characteristics that make SPARO unique. Chief among these characteristics are an increased beam size ( 4') for large-scale mapping of magnetic fields and innovations to the cryostat design to ensure smooth operation during the austral winter. We also include a discussion of systematic effects of the SPARO-Viper system and observations of NGC 6334 and the Galactic center obtained at South Pole during July 2000.

  3. Cotton-Mouton polarimeter with HCN laser on CHS

    SciTech Connect

    Akiyama, T.; Kawahata, K.; Ito, Y.; Okajima, S.; Nakayama, K.; Okamura, S.; Matsuoka, K.; Isobe, M.; Nishimura, S.; Suzuki, C.; Yoshimura, Y.; Nagaoka, K.; Takahashi, C.

    2006-10-15

    Polarimeters based on the Cotton-Mouton effect hold promise for electron density measurements. We have designed and installed a Cotton-Mouton polarimeter on the Compact Helical System. The Cotton-Mouton effect is measured as the phase difference between probe and reference beams. In this system, an interferometric measurement can be performed simultaneously with the same probe chord. The light source is a HCN laser (wavelength of 337 {mu}m). Digital complex demodulation is adopted for small phase analysis. The line averaged density evaluated from the polarimeter along a plasma center chord is almost consistent with that from the interferometer.

  4. A compton backscattering polarimeter for measuring longitudinal electron polarization

    SciTech Connect

    I. Passchier; Douglas W. Higinbotham; N. Vodinas; N. Papadakis; Kees de Jager; Ricardo Alarcon; T. Bauer; J.F.J. van den Brand; D. Boersma; T. Botto; M. Bouwhuis; H.J. Bulten; L. van Buuren; Rolf Ent; D. Geurts; M. Ferro-Luzzi; M. Harvey; Peter Heimberg; Blaine Norum; H.R. Poolman; M. van der Putte; E. Six; J.J.M. Steijger; D. Szczerba; H. de Vries

    1997-08-01

    Compton backscattering polarimetry provides a fast measurement of the polarization of an electron beam in a storage ring. Since the method is non-destructive, the polarization of the electrons can be monitored during internal target experiments. At NIKHEF a Compton polarimeter has been constructed to measure the polarization of the longitudinally polarized electrons stored in the AmPS ring. First results obtained with the polarimeter, the first Compton polarimeter to measure the polarization of a stored longitudinally polarized electron beam, are presented in this paper.

  5. Parallel detecting, spectroscopic ellipsometers/polarimeters

    DOEpatents

    Furtak, Thomas E.

    2002-01-01

    The parallel detecting spectroscopic ellipsometer/polarimeter sensor has no moving parts and operates in real-time for in-situ monitoring of the thin film surface properties of a sample within a processing chamber. It includes a multi-spectral source of radiation for producing a collimated beam of radiation directed towards the surface of the sample through a polarizer. The thus polarized collimated beam of radiation impacts and is reflected from the surface of the sample, thereby changing its polarization state due to the intrinsic material properties of the sample. The light reflected from the sample is separated into four separate polarized filtered beams, each having individual spectral intensities. Data about said four individual spectral intensities is collected within the processing chamber, and is transmitted into one or more spectrometers. The data of all four individual spectral intensities is then analyzed using transformation algorithms, in real-time.

  6. Experimental validation of Mueller-Stokes theory and investigation of the influence of the Cotton-Mouton effect on polarimetry in a magnetized fusion plasma

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Peebles, W. A.; Crocker, N. A.; Carter, T. A.; Doyle, E. J.; Hyatt, A. W.; Rhodes, T. L.; Wang, G.; Zeng, L.

    2013-10-01

    Mueller-Stokes theory can be used to calculate the polarization evolution of an electromagnetic (EM) wave as it propagates through a magnetized plasma. Historically, the theory has been used to interpret polarimeter signals from systems operating on fusion plasmas. These interpretations have mostly employed approximations of Mueller-Stokes theory in regimes where either the Faraday rotation (FR) or the Cotton-Mouton (CM) effect is dominant. The current paper presents the first systematic comparison of polarimeter measurements with the predictions of full Mueller-Stokes theory where conditions transition smoothly from a FR-dominant (i.e., weak CM effect) plasma to one where the CM effect plays a significant role. A synthetic diagnostic code, based on Mueller-Stokes theory accurately reproduces the trends evident in the experimentally measured polarimeter phase over this entire operating range, thereby validating Mueller-Stokes theory. The synthetic diagnostic code is then used to investigate the influence of the CM effect on polarimetry measurements. As expected, the measurements are well approximated by the FR effect when the CM effect is predicted to be weak. However, the code shows that as the CM effect increases, it can compete with the FR effect in rotating the polarization of the EM-wave. This results in a reduced polarimeter response to the FR effect, just as observed in the experiment. The code also shows if sufficiently large, the CM effect can even reverse the handedness of a wave launched with circular polarization. This helps to understand the surprising experimental observations that the sensitivity to the FR effect can be nearly eliminated at high enough BT (2.0 T). The results also suggest that the CM effect on the plasma midplane can be exploited to potentially measure magnetic shear in tokamak plasmas. These results establish increased confidence in the use of such a synthetic diagnostic code to guide future polarimetry design and interpret the

  7. Experimental validation of Mueller-Stokes theory and investigation of the influence of the Cotton-Mouton effect on polarimetry in a magnetized fusion plasma

    SciTech Connect

    Zhang, J.; Peebles, W. A.; Crocker, N. A.; Carter, T. A.; Doyle, E. J.; Rhodes, T. L.; Wang, G.; Zeng, L.; Hyatt, A. W.

    2013-10-15

    Mueller-Stokes theory can be used to calculate the polarization evolution of an electromagnetic (EM) wave as it propagates through a magnetized plasma. Historically, the theory has been used to interpret polarimeter signals from systems operating on fusion plasmas. These interpretations have mostly employed approximations of Mueller-Stokes theory in regimes where either the Faraday rotation (FR) or the Cotton-Mouton (CM) effect is dominant. The current paper presents the first systematic comparison of polarimeter measurements with the predictions of full Mueller-Stokes theory where conditions transition smoothly from a FR-dominant (i.e., weak CM effect) plasma to one where the CM effect plays a significant role. A synthetic diagnostic code, based on Mueller-Stokes theory accurately reproduces the trends evident in the experimentally measured polarimeter phase over this entire operating range, thereby validating Mueller-Stokes theory. The synthetic diagnostic code is then used to investigate the influence of the CM effect on polarimetry measurements. As expected, the measurements are well approximated by the FR effect when the CM effect is predicted to be weak. However, the code shows that as the CM effect increases, it can compete with the FR effect in rotating the polarization of the EM-wave. This results in a reduced polarimeter response to the FR effect, just as observed in the experiment. The code also shows if sufficiently large, the CM effect can even reverse the handedness of a wave launched with circular polarization. This helps to understand the surprising experimental observations that the sensitivity to the FR effect can be nearly eliminated at high enough B{sub T} (2.0 T). The results also suggest that the CM effect on the plasma midplane can be exploited to potentially measure magnetic shear in tokamak plasmas. These results establish increased confidence in the use of such a synthetic diagnostic code to guide future polarimetry design and interpret

  8. Recent Results from the C-Mod Polarimeter

    NASA Astrophysics Data System (ADS)

    Xu, P.; Irby, J. H.; Bergerson, W. F.; Brower, D. L.; Ding, W. X.; Marmar, E. S.; Delgado-Aparicio, L.; Ernst, D.; Hughes, J. W.; Mumgaard, R.; Parker, R.; Scott, S.; Shiraiwa, S.; Wallace, G. M.; White, A. E.; Wolfe, S. M.

    2013-10-01

    The C-Mod 3 chord FIR polarimeter, with a 2 MHz bandwidth, is capable of responding to both fast changes in the plasma equilibrium and high frequency fluctuations. It operates under ITER-like plasma conditions and magnetic fields, and uses an optical layout and FIR sources very similar to those proposed for the ITER polarimeter. Results from the polarimeter as a function of plasma density and current will be discussed, as well as the effects of lower hybrid power levels, phasing and plasma density on the current drive efficiency. The possible identification of some broadband fluctuations as primarily magnetic in nature, and gyrokinetic simulation results from the modeling of these fluctuations will also be presented. Estimates of the localization of this mode will be described. The polarimeter response to low frequency MHD modes will be compared with results from the Fast Two-Color-Interferometer. USDoE contract DE-FC02-99ER54512.

  9. Drift parameters optimization of a TPC polarimeter: a simulation study

    NASA Astrophysics Data System (ADS)

    Rakhee, K.; Radhakrishna, V.; Koushal, V.; Baishali, G.; Vinodkumar, A. M.

    2015-06-01

    Time Projection Chamber (TPC) based X-ray polarimeters using Gas Electron Multiplier (GEM) are currently being developed to make sensitive measurement of polarization in 2-10 keV energy range. The emission direction of the photoelectron ejected via photoelectric effect carries the information of the polarization of the incident X-ray photon. Performance of a gas based polarimeter is affected by the operating drift parameters such as gas pressure, drift field and drift-gap. We present simulation studies carried out in order to understand the effect of these operating parameters on the modulation factor of a TPC polarimeter. Models of Garfield are used to study photoelectron interaction in gas and drift of electron cloud towards GEM. Our study is aimed at achieving higher modulation factors by optimizing drift parameters. Study has shown that Ne/DME (50/50) at lower pressure and drift field can lead to desired performance of a TPC polarimeter.

  10. The SLAC E-154 {sup 3}He polarimeter

    SciTech Connect

    Romalis, M. V.; Bogorad, P. L.; Cates, G. D.; Kumar, K. S.; Chupp, T. E.; Coulter, K. P.; Smith, T. B.; Welsh, R.; Hughes, E. W.; Johnson, J. R.; Thompson, A. K.

    1998-01-20

    We describe the NMR and Rb Zeeman frequency shift polarimeters used for determining the {sup 3}He polarization in a recent precision measurement of the neutron spin structure function g{sub 1} at SLAC (E-154). We performed a detailed study of the systematic errors associated with the calibration of the NMR polarimeter. A new technique was used for determining the {sup 3}He polarization from the frequency shift of the Rb Zeeman resonance.

  11. Calibration and Compensation of Instrumental Errors in Imaging Polarimeters

    DTIC Science & Technology

    2007-04-01

    Polarimeters The microgrid polarimeter that we considered is designed to work in the long- wave infrared (LWIR) 7.8 - 9.8 Pm band and has a mosaic of...helps to characterize shape and surface characteristics of interesting targets in optical imagery from the UV through the LWIR and beyond. There are...discovered that polarization is important, but it can also be quite difficult to measure accurately. Optical systems designed to respond to polarization

  12. Absolute calibration and beam background of the Squid Polarimeter

    SciTech Connect

    Blaskiewicz, M.M.; Cameron, P.R.; Shea, T.J.

    1996-12-31

    The problem of beam background in Squid Polarimetry is not without residual benefits. The authors may deliberately generate beam background by gently kicking the beam at the spin tune frequency. This signal may be used to accomplish a simple and accurate absolute calibration of the polarimeter. The authors present details of beam background calculations and their application to polarimeter calibration, and suggest a simple proof-of-principle accelerator experiment.

  13. A Disconnect between Staff and Student Perceptions of Learning: An ACELL Educational Analysis of the First Year Undergraduate Chemistry Experiment "Investigating Sugar Using a Home Made Polarimeter"

    ERIC Educational Resources Information Center

    Crisp, Michael G.; Kable, Scott H.; Read, Justin R.; Buntine, Mark A.

    2011-01-01

    This paper describes an educational analysis of a first year university chemistry practical called "Investigating sugar using a home made polarimeter". The analysis follows the formalism of the Advancing Chemistry by Enhancing Learning in the Laboratory (ACELL) project, which includes a statement of education objectives, and an analysis…

  14. Next Generation X-ray Polarimeter

    NASA Astrophysics Data System (ADS)

    Hill-Kittle, Joe

    The emission regions of many types of X-ray sources are small and cannot be spatially resolved without interferometry techniques that haven't yet been developed. In order to understand the emission mechanisms and emission geometry, alternate measurement techniques are required. Most microphysical processes that affect X-rays, including scattering and magnetic emission processes are imprinted as polarization signatures. X-ray polarization also reveals exotic physical processes occurring in regions of very strong gravitational and magnetic fields. Observations of X-ray polarization will provide a measurement of the geometrical distribution of gas and magnetic fields without foreground depolarization that affects longer wavelengths (e.g. Faraday rotation in the radio). Emission from accretion disks has an inclination-dependent polarization. The polarization signature is modified by extreme gravitational forces, which bend light, essentially changing the contribution of each part of the disk to the integrated total intensity seen by distant observers. Because gravity has the largest effect on the innermost parts of the disk (which are the hottest, and thus contributes to more high energy photons), the energy dependent polarization is diagnostic of disk inclination, black hole mass and spin. Increasing the sensitive energy band will make these measurements possible. X-ray polarimetry will also enable the study of the origin of cosmic rays in the universe, the nature of black holes, the role of black holes in the evolution of galaxies, and the interaction of matter with the highest physically possible magnetic fields. These objectives address NASA's strategic interest in the origin, structure, and evolution of the universe. We propose a two-year effort to develop the Next Generation X-ray Polarimeter (NGXP) that will have more than ten times the sensitivity of the current state of the art. NGXP will make possible game changing measurements of classes of astrophysical

  15. Optimization of system parameters for a complete multispectral polarimeter

    SciTech Connect

    Hollstein, Andre; Ruhtz, Thomas; Fischer, Juergen; Preusker, Rene

    2009-08-20

    We optimize a general class of complete multispectral polarimeters with respect to signal-to-noise ratio, stability against alignment errors, and the minimization of errors regarding a given set of polarization states. The class of polarimeters that are dealt with consists of at least four polarization optics each with a multispectral detector. A polarization optic is made of an azimuthal oriented wave plate and a polarizing filter. A general, but not unique, analytic solution that minimizes signal-to-noise ratio is introduced for a polarimeter that incorporates four simultaneous measurements with four independent optics. The optics consist of four sufficient wave plates, where at least one is a quarter-wave plate. The solution is stable with respect to the retardance of the quarter-wave plate; therefore, it can be applied to real-world cases where the retardance deviates from {lambda}/4. The solution is a set of seven rotational parameters that depends on the given retardances of the wave plates. It can be applied to a broad range of real world cases. A numerical method for the optimization of arbitrary polarimeters of the type discussed is also presented and applied for two cases. First, the class of polarimeters that were analytically dealt with are further optimized with respect to stability and error performance with respect to linear polarized states. Then a multispectral case for a polarimeter that consists of four optics with real achromatic wave plates is presented. This case was used as the theoretical background for the development of the Airborne Multi-Spectral Sunphoto- and Polarimeter (AMSSP), which is an instrument for the German research aircraft HALO.

  16. Optimization of system parameters for a complete multispectral polarimeter.

    PubMed

    Hollstein, André; Ruhtz, Thomas; Fischer, Jürgen; Preusker, René

    2009-08-20

    We optimize a general class of complete multispectral polarimeters with respect to signal-to-noise ratio, stability against alignment errors, and the minimization of errors regarding a given set of polarization states. The class of polarimeters that are dealt with consists of at least four polarization optics each with a multispectral detector. A polarization optic is made of an azimuthal oriented wave plate and a polarizing filter. A general, but not unique, analytic solution that minimizes signal-to-noise ratio is introduced for a polarimeter that incorporates four simultaneous measurements with four independent optics. The optics consist of four sufficient wave plates, where at least one is a quarter-wave plate. The solution is stable with respect to the retardance of the quarter-wave plate; therefore, it can be applied to real-world cases where the retardance deviates from lambda/4. The solution is a set of seven rotational parameters that depends on the given retardances of the wave plates. It can be applied to a broad range of real world cases. A numerical method for the optimization of arbitrary polarimeters of the type discussed is also presented and applied for two cases. First, the class of polarimeters that were analytically dealt with are further optimized with respect to stability and error performance with respect to linear polarized states. Then a multispectral case for a polarimeter that consists of four optics with real achromatic wave plates is presented. This case was used as the theoretical background for the development of the Airborne Multi-Spectral Sunphoto- and Polarimeter (AMSSP), which is an instrument for the German research aircraft HALO.

  17. Performance of the PRAXyS X-ray polarimeter

    NASA Astrophysics Data System (ADS)

    Iwakiri, W. B.; Black, J. K.; Cole, R.; Enoto, T.; Hayato, A.; Hill, J. E.; Jahoda, K.; Kaaret, P.; Kitaguchi, T.; Kubota, M.; Marlowe, H.; McCurdy, R.; Takeuchi, Y.; Tamagawa, T.

    2016-12-01

    The performance of the Time Projection Chamber (TPC) polarimeter for the Polarimeter for Relativistic Astrophysical X-ray Sources (PRAXyS) Small Explorer was evaluated using polarized and unpolarized X-ray sources. The PRAXyS mission will enable exploration of the universe through X-ray polarimetry in the 2-10 keV energy band. We carried out performance tests of the polarimeter at the Brookhaven National Laboratory, National Synchrotron Light Source (BNL-NSLS) and at NASA's Goddard Space Flight Center. The polarimeter was tested with linearly polarized, monochromatic X-rays at 11 different energies between 2.5 and 8.0 keV. At maximum sensitivity, the measured modulation factors at 2.7, 4.5 and 8.0 keV are 27%, 43% and 59%, respectively and the measured angle of polarization is consistent with the expected value at all energies. Measurements with a broadband, unpolarized X-ray source placed a limit of less than 1% on false polarization in the PRAXyS polarimeter.

  18. Simulation studies on performance parameters of a TPC polarimeter

    NASA Astrophysics Data System (ADS)

    Rakhee, K.; Koushal, V.; Radhakrishna, V.; Baishali, G.; A. M., Vinodkumar

    2014-07-01

    X-ray polarimeters based on Time Projection Chamber (TPC) geometry are currently being studied and developed to make sensitive measurement of polarization in 2-10keV energy range. TPC soft X-ray polarimeters exploit the fact that emission direction of the photoelectron ejected via photoelectric effect in a gas proportional counter carries the information of the polarization of the incident X-ray photon. Operating parameters such as pressure, drift field and driftgap affect the performance of a TPC polarimeter. Simulations presented here showcase the effect of these operating parameters on the modulation factor of the TPC polarimeter. Models of Garfield are used to study photoelectron interaction in gas and drift of electron cloud towards Gas Electron Multiplier (GEM). The emission direction is reconstructed from the image and modulation factor is computed. Our study has shown that Ne/DME (50/50) at lower pressure and drift field can be used for a TPC polarimeter with modulation factor of 50-65%.

  19. Performance of the PRAXyS X-Ray Polarimeter

    NASA Technical Reports Server (NTRS)

    Iwakiri, W.B.; Black, J. K.; Cole, R.; Enoto, T.; Hayato, A.; Hill, J. E.; Jahoda, K.; Kaaret, P.; Kitaguchi, T.; Kubota, M.; Marlowe, H.; McCurdy, R.; Takeuchi, Y.; Tamagawa, T.

    2016-01-01

    The performance of the Time Projection Chamber (TPC) polarimeter for the Polarimeter for Relativistic Astrophysical X-ray Sources (PRAXyS) Small Explorer was evaluated using polarized and unpolarized X-ray sources. The PRAXyS mission will enable exploration of the universe through X-ray polarimetry in the 2-10 keV energy band. We carried out performance tests of the polarimeter at the Brookhaven National Laboratory, National Synchrotron Light Source (BNL-NSLS) and at NASA's Goddard Space Flight Center. The polarimeter was tested with linearly polarized, monochromatic X-rays at 11 different energies between 2.5 and 8.0 keV. At maximum sensitivity, the measured modulation factors at 2.7, 4.5 and 8.0 keV are 27%, 43% and 59%, respectively and the measured angle of polarization is consistent with the expected value at all energies. Measurements with a broadband, unpolarized X-ray source placed a limit of less than 1% on false polarization in the PRAXyS polarimeter.

  20. Design of a mid-IR polarimeter for SOFIA

    NASA Astrophysics Data System (ADS)

    Packham, C.; Escuti, M.; Boreman, G.; Quijano, I.; Ginn, J. C.; Franklin, B.; Axon, D. J.; Hough, J. H.; Jones, T. J.; Roche, P. F.; Tamura, M.; Telesco, C. M.; Levenson, N.; Rodgers, J. M.; McGuire, J. P.

    2008-07-01

    Mid-infrared polarimetry remains an underexploited technique; where available it is limited in spectral coverage from the ground, and conspicuously absent from the Spitzer, JWST and Herschel instrument suites. The unique characteristics of SOFIA afford unprecedented spectral coverage and sensitivity in the mid-infrared waveband. We discuss the preliminary optical design for a 5-40μm spectro-polarimeter for use on SOFIA, the SOFIA Mid-InfraRed Polarimeter (SMIRPh). The design furthers the existing 5-40μm imaging and spectroscopic capabilities of SOFIA, and draws on experience gained through the University of Florida's mid-IR imagers, spectrometer and polarimeter designs of T-ReCS and CanariCam. We pay special attention to the challenges of obtaining polarimetric materials suitable at both these wavelengths and cryogenic temperatures. Finally, we (briefly) present an overview of science highlights that could be performed from a 5-40μm imaging- and spectro-polarimeter on SOFIA. Combined with the synergy between the possible future far-IR polarimeter, Hale, this instrument would provide the SOFIA community with unique and exciting science capabilities, leaving a unique scientific legacy.

  1. Improved microgrid arrangement for integrated imaging polarimeters.

    PubMed

    LeMaster, Daniel A; Hirakawa, Keigo

    2014-04-01

    For almost 20 years, microgrid polarimetric imaging systems have been built using a 2×2 repeating pattern of polarization analyzers. In this Letter, we show that superior spatial resolution is achieved over this 2×2 case when the analyzers are arranged in a 2×4 repeating pattern. This unconventional result, in which a more distributed sampling pattern results in finer spatial resolution, is also achieved without affecting the conditioning of the polarimetric data-reduction matrix. Proof is provided theoretically and through Stokes image reconstruction of synthesized data.

  2. An Interview with John Stokes.

    ERIC Educational Resources Information Center

    Becker, Ellen Bennett

    1996-01-01

    As teacher, musician, and performing artist, John Stokes has traveled widely in his efforts to promote awareness of the natural world and the integrity of indigenous peoples. In this interview, Stokes discusses life experiences that led him to establish the Tracking Project, a program that has taught traditional tracking and survival skills to…

  3. The ability to use remote polarization studies of Earth from space in the national economy (Project of the onboard filter panoramic polarimeter)

    NASA Astrophysics Data System (ADS)

    Nevodovskyi, P. V.; Vidmachenko, A. P.; Geraimchuk, M. D.; Ivahiv, O. V.

    2016-10-01

    Remote polarization studies are a very powerful method of solving of astronomical tasks with the study of the physical properties of the planets and their atmospheres. It allows research of objects as in situ, so in vitro, and has many other advantages. To use this method has already been developed and are continuing the development of many various special instruments called polarimeters. The essence of the space experiment consists in the fact to using the polarimeter installed on board a micro satellite, systematically, during each of its revolutions around the Earth, to monitor a polarization components of a diffusely reflected by atmosphere solar radiation in different, previously stipulated wavelengths. There are a lot of the optical schemes, which are used in devices of measuring and monitoring of parameters of polarized radiation, including those into space experiments of probing of the Earth's atmosphere from orbit of satellites. In this paper we analyze the potential for use of filter-polarimeter to measure the Stokes vector components.

  4. Algoritm of processing and methodology of polarimetric measurement of light flux in the polarimeters with rotating hollow rotor

    NASA Astrophysics Data System (ADS)

    Vidmachenko, A. P.

    2016-11-01

    It is known that all detectors of electromagnetic radiation react only to change of light intensity without registering of the state of its polarization. For this reason, to determine the degree of light polarization used transformation of parameters of the Stokes vector I = I{I0, Q, U, V} from the radiation source into a scalar value. For this purpose, used a special devices (polaroid modulators), which are installed in front of the radiation detectors. When light passes through the polaroids, prisms, etc. there is an optical path difference between the orthogonal component of the vector I. The magnitude of this difference is proportional to the square of the electric field. At the used by us polarimeters we apply a two-element modulator.

  5. Run-09 pC polarimeter analysis

    SciTech Connect

    Alekseev, I.; Aschenauer, E.; Atoyan, G.; Bazilevsky, A.; Gill, R.; Huang, H.; Lee, S.; Li, X.; Makdisi, Y.; Morozov, B.; Nakagawa, I.; Svirida, D.; Zelenski, A.

    2010-08-01

    Analysis of PC polarimeter data at {radical}s = 200 and 500 GeV from Run9 is presented. Final polarization results, fill-by-fill, for blue and yellow beams, as to be used by RHIC experiments (in collisions) are released and collected in http://www4.rcf.bnl.gov/cnipol/pubdocs/Run09Offline/. Global relative systematic uncertainties {delta}P/P (to be considered as correlated from fill to fill) are 4.7% for 100 GeV beams, and 8.3% (12.1%) for blue (yellow) 250 GeV beams. For a product of two beam polarizations P{sub B} {center_dot} P{sub Y} (used in double spin asymmetry measurements) the relative uncertainty {delta}(P{sub B} {center_dot} P{sub Y})/(P{sub B} {center_dot} P{sub Y}) 8.8% for 100 GeV beams and 18.5% for 250 GeV beams. For the average between two beam polarization (P{sub B} + P{sub Y})/2 (used in single spin asymmetry measurements, when data from two polarized beams are combined) the relative uncertainty is 4.4% for 100 GeV beams and 9.2% for 250 GeV beams. Larger uncertainties for 250 GeV beams relate to significant rate related systematic effects experienced in the first part of Run9 (due to thicker targets used and smaller trans. beam size at higher beam energy).

  6. About study of radiation flux carried out on the stand, which is designed for testing of space ultraviolet polarimeter

    NASA Astrophysics Data System (ADS)

    Nevodovskiy, P. V.; Vidmachenko, A. P.; Geraimchuk, M. D.; Ivahiv, O. V.

    2016-08-01

    In the Main Astronomical Observatory of NAS of Ukraine, National Technical University of Ukraine "KPI" and National University "Lviv Polytechnic" over the many years has accumulated considerable experience of work on the design and development of polarimeters, and created a working model of compact an onboard ultraviolet polarimeter (UFP) [1-6]. For debugging, research and testing as the entire layout of UFP and its individual parts we have created a special stand with complex equipment that allows carrying the following works. The structural construction of the stand allows obtaining characteristics as a whole unit, and its individual parts; obtaining spectral dependences and counting characteristics signal of the light radiation, and of dark signal; carry out the polarization measurements and more. For this stand developed a number of special techniques to study various parameters of all UFP appliance and its individual parts. Thus, for control - characteristics and calibration of elements of photo-detector system of electro-optical equipment, must use the reference emitters. But they are complicated and expensive. Therefore for simplified calibration and configuration of optical devices, it is expedient to use cheap and small in size, but specially selected LEDs. For this, developed for testing of UFP stand, has been modernized. Thus, the selection was carried out, and then carefully studied the sources of radiation, that will be used for calibration of polarimeters. More information on this work expounded in the report. References. 1. P. Nevodovskyi, O. Morozhenko, A. Vidmachenko, O. Ivakhiv, M. Geraimchuk, O. Zbrutskyi. Tiny Ultraviolet Polarimeter for Earth Stratosphere from Space Investigation // Proceedings of 8th IEEE International Conference on Intelligent Data Acquisition and Advanced Computing Systems: Technology and Applications (IDAACS'2015). 24-26 September 2015, Proceedings. Warsaw, Poland. Vol.81, p. 28-32. 2. Nevodovsksiy P. V., Morozhenko A. V

  7. Electron Beam Moller Polarimeter at Jlab Hall a

    NASA Astrophysics Data System (ADS)

    Glamazdin, A.V.; Gorbenko, V.G.; Levchuk, L.G.; Pomatsalyuk, L.; Rubashkin, A.L.; Sorokin, P.V.; Dale, D.S.; Doyle, B.; Gorringe, T.; Korsch, W.; Zeps, V.; Chen, J.O.; Chudakov, E.; Nanda, S.; Saha, A.; Gasparian, A.

    As part of the spin-physics program at Jefferson Laboratory (JLab), a Mo ller polarimeter was developed to measure the polarization of electron beam of energies 0.8 to 5.0 GeV. A unique signature for Mo ller scattering is obtained using a series of three quadrupole magnets which provide an angular selection, and a dipole magnet for energy analysis. The design, commissioning and the first results of the polarization measurements of this polarimeter will be presented as well as future plans to use its small scattering angle capabilities to investigate physics in very low Q2 regime.

  8. Calibration method of microgrid polarimeters with image interpolation.

    PubMed

    Chen, Zhenyue; Wang, Xia; Liang, Rongguang

    2015-02-10

    Microgrid polarimeters have large advantages over conventional polarimeters because of the snapshot nature and because they have no moving parts. However, they also suffer from several error sources, such as fixed pattern noise (FPN), photon response nonuniformity (PRNU), pixel cross talk, and instantaneous field-of-view (IFOV) error. A characterization method is proposed to improve the measurement accuracy in visible waveband. We first calibrate the camera with uniform illumination so that the response of the sensor is uniform over the entire field of view without IFOV error. Then a spline interpolation method is implemented to minimize IFOV error. Experimental results show the proposed method can effectively minimize the FPN and PRNU.

  9. Stokes-polarimetry imaging of tissue

    NASA Astrophysics Data System (ADS)

    Wu, Paul J.

    A novel Stokes-polarimetry imaging system and technique was developed to quantify fully the polarization properties of light remitted from tissue. The uniqueness of the system and technique is established in the incident polarization. Here, the diffuse illumination is varied and controlled with the intention to improve the visibility of tissue structures. Since light retains some polarization even after multiple-scattering events, the polarization of remitted light depends upon the interactions within the material. Differentiation between tissue structures is accomplished by two-dimensional mapping of the imaged area using metrics such as the degree of linear polarization, degree of circular polarization, ellipticity, and Stokes parameters. While Stokes-polarimetry imaging can be applied to a variety of tissues and conditions, this thesis focuses on tissue types associated with the disease endometriosis. The current standard in diagnosing endometriosis is visual laparoscopy with tissue biopsy. The documented correlation between laparoscopy inspection and histological confirmation of suspected lesions was at best 67%. Endometrial lesions vary greatly in their appearance and depth of infiltration. Although laparoscopy permits tissue to be assessed by color and texture, to advance beyond the state-of-the-art, a new imaging modality involving polarized light was investigated; in particular, Stokes-polarimetry imaging was used to determine the polarization signature of light that interacted with tissue. Basic science studies were conducted on rat tails embedded within turbid gelatin. The purpose of these experiments was to determine how identification of sub-surface structures could be improved. Experimental results indicate image contrast among various structures such as tendon, soft tissue and intervertebral discs. Stokes-polarimetry imaging experiments were performed on various tissues associated with endometriosis to obtain a baseline characterization for each

  10. Performance Verification of the Gravity and Extreme Magnetism Small Explorer GEMS X-Ray Polarimeter

    NASA Technical Reports Server (NTRS)

    Enoto, Teruaki; Black, J. Kevin; Kitaguchi, Takao; Hayato, Asami; Hill, Joanne E.; Jahoda, Keith; Tamagawa, Toru; Kanako, Kenta; Takeuchi, Yoko; Yoshikawa, Akifumi; Kenward, David

    2014-01-01

    olarimetry is a powerful tool for astrophysical observations that has yet to be exploited in the X-ray band. For satellite-borne and sounding rocket experiments, we have developed a photoelectric gas polarimeter to measure X-ray polarization in the 2-10 keV range utilizing a time projection chamber (TPC) and advanced micro-pattern gas electron multiplier (GEM) techniques. We carried out performance verification of a flight equivalent unit (1/4 model) which was planned to be launched on the NASA Gravity and Extreme Magnetism Small Explorer (GEMS) satellite. The test was performed at Brookhaven National Laboratory, National Synchrotron Light Source (NSLS) facility in April 2013. The polarimeter was irradiated with linearly-polarized monochromatic X-rays between 2.3 and 10.0 keV and scanned with a collimated beam at 5 different detector positions. After a systematic investigation of the detector response, a modulation factor greater than or equal to 35% above 4 keV was obtained with the expected polarization angle. At energies below 4 keV where the photoelectron track becomes short, diffusion in the region between the GEM and readout strips leaves an asymmetric photoelectron image. A correction method retrieves an expected modulation angle, and the expected modulation factor, approximately 20% at 2.7 keV. Folding the measured values of modulation through an instrument model gives sensitivity, parameterized by minimum detectable polarization (MDP), nearly identical to that assumed at the preliminary design review (PDR).

  11. Performance verification of the Gravity and Extreme Magnetism Small explorer (GEMS) x-ray polarimeter

    NASA Astrophysics Data System (ADS)

    Enoto, Teruaki; Black, J. Kevin; Kitaguchi, Takao; Hayato, Asami; Hill, Joanne E.; Jahoda, Keith; Tamagawa, Toru; Kaneko, Kenta; Takeuchi, Yoko; Yoshikawa, Akifumi; Marlowe, Hannah; Griffiths, Scott; Kaaret, Philip E.; Kenward, David; Khalid, Syed

    2014-07-01

    Polarimetry is a powerful tool for astrophysical observations that has yet to be exploited in the X-ray band. For satellite-borne and sounding rocket experiments, we have developed a photoelectric gas polarimeter to measure X-ray polarization in the 2-10 keV range utilizing a time projection chamber (TPC) and advanced micro-pattern gas electron multiplier (GEM) techniques. We carried out performance verification of a flight equivalent unit (1/4 model) which was planned to be launched on the NASA Gravity and Extreme Magnetism Small Explorer (GEMS) satellite. The test was performed at Brookhaven National Laboratory, National Synchrotron Light Source (NSLS) facility in April 2013. The polarimeter was irradiated with linearly-polarized monochromatic X-rays between 2.3 and 10.0 keV and scanned with a collimated beam at 5 different detector positions. After a systematic investigation of the detector response, a modulation factor >=35% above 4 keV was obtained with the expected polarization angle. At energies below 4 keV where the photoelectron track becomes short, diffusion in the region between the GEM and readout strips leaves an asymmetric photoelectron image. A correction method retrieves an expected modulation angle, and the expected modulation factor, ~20% at 2.7 keV. Folding the measured values of modulation through an instrument model gives sensitivity, parameterized by minimum detectable polarization (MDP), nearly identical to that assumed at the preliminary design review (PDR).

  12. Far infrared polarimeter with very low instrumental polarization

    NASA Astrophysics Data System (ADS)

    Battistelli, Elia S.; De Petris, Marco; Lamagna, Luca; Maoli, Roberto; Melchiorri, Francesco; Palladino, Emilia; Savini, Giorgio; Mauskopf, Philip D.; Orlando, Angiola

    2003-02-01

    After a short analysis of the main problems involved in the construction of a Far Infrared polarimeter with very low instrumental noise, we describe the instrument that will be employed at MITO telescope to search for calibration sources and investigate polarization near the CMB anisotropy peaks in the next campaign (Winter 2002-03).

  13. The Compton Polarimeter in Hall C of Jefferson

    NASA Astrophysics Data System (ADS)

    Narayan, Amrendra

    2013-04-01

    A new Compton polarimeter was installed in Hall C at Jefferson Lab and used during the Qweak experiment which aims to measure the weak charge of proton with a precision of 4.1%. In this polarimeter the electron beam collides with green laser light stored in a low gain Fabry-Perot Cavity; the scattered electrons are detected in 4 planes of a novel diamond micro strip detector while the back scattered photons are detected in a lead tungstate crystal. We extract the beam polarization by fitting the experimental asymmetry for each detector strip to the corresponding asymmetry calculated in QED. During the experiment, we took data to cross-calibrate Moller and Compton polarimeters in Hall C. We will share our preliminary conclusions from this comparison. In this talk, we will also present the results from Monte Carlo studies performed to estimate the systematic uncertainties of the polarization measurement along with comparing results from two independent extraction of the polarization involving very different time scales. The Compton polarimeter has achieved the design goals of 1% statistical uncertainty per hour and we expect to achieve less than 1% systematic uncertainty.

  14. MOPTOP: a multi-colour optimised optical polarimeter

    NASA Astrophysics Data System (ADS)

    Jermak, Helen; Steele, Iain A.; Smith, Robert J.

    2016-08-01

    We present the design and science case for the Liverpool Telescope's fourth-generation polarimeter; MOPTOP: a Multicolour OPTimised Optical Polarimeter which is optimised for sensitivity and bi-colour observations. We introduce an optimised polarimeter which is as far as possible limited only by the photon counting efficiency of the detectors. Using a combination of CMOS cameras, a continuously rotating half-wave plate and a wire grid polarising beamsplitter, we predict we can accurately measure the polarisation of sources to 1% at 19th magnitude in 10 minutes on a 2 metre telescope. For brighter sources we anticipate much low systematics (< 0.1%) than our current polarimeter. The design also gives the ability to measure polarization and photometric variability on timescales as short as a few seconds. Overall the instrument will allow accurate measurements of the intra-nightly variability of the polarisation of sources such as gamma-ray bursts and blazars (AGN orientated with the jet pointing toward the observer), allowing the constraint of magnetic field models revealing more information about the formation, ejection and collimation of jets.

  15. Intrinsic character of Stokes matrices

    NASA Astrophysics Data System (ADS)

    Gagnon, Jean-François; Rousseau, Christiane

    2017-02-01

    Two germs of linear analytic differential systems x k + 1Y‧ = A (x) Y with a non-resonant irregular singularity are analytically equivalent if and only if they have the same eigenvalues and equivalent collections of Stokes matrices. The Stokes matrices are the transition matrices between sectors on which the system is analytically equivalent to its formal normal form. Each sector contains exactly one separating ray for each pair of eigenvalues. A rotation in S allows supposing that R+ lies in the intersection of two sectors. Reordering of the coordinates of Y allows ordering the real parts of the eigenvalues, thus yielding triangular Stokes matrices. However, the choice of the rotation in x is not canonical. In this paper we establish how the collection of Stokes matrices depends on this rotation, and hence on a chosen order of the projection of the eigenvalues on a line through the origin.

  16. The Primordial Inflation Explorer (PIXIE): A Nulling Polarimeter for Cosmic Microwave Background Observations

    NASA Technical Reports Server (NTRS)

    Kogut, Alan J.; Fixsen, D. J.; Chuss, D. T.; Dotson, J.; Dwek, E.; Halpern, M.; Hinshaw, G. F.; Meyer, S. M.; Moseley, S. H.; Seiffert, M. D.; Spergel, D. N.; Wollack, E. J.

    2011-01-01

    The Primordial Inflation Explorer (PIXIE) is a concept for an Explorer-class mission to measure the gravity-wave signature of primordial inflation through its distinctive imprint on the linear polarization of the cosmic microwave background. The instrument consists of a polarizing Michelson interferometer configured as a nulling polarimeter to measure the difference spectrum between orthogonal linear polarizations from two co-aligned beams. Either input can view the sky or a temperature-controlled absolute reference blackbody calibrator. Rhe proposed instrument can map the absolute intensity and linear polarization (Stokes I, Q, and U parameters) over the full sky in 400 spectral channels spanning 2.5 decades in frequency from 30 GHz to 6 THz (1 cm to 50 micron wavelength). Multi-moded optics provide background-limited sensitivity using only 4 detectors, while the highly symmetric design and multiple signal modulations provide robust rejection of potential systematic errors. The principal science goal is the detection and characterization of linear polarization from an inflationary epoch in the early universe, with tensor-to-scalar ratio r < 10..3 at 5 standard deviations. The rich PIXIE data set can also constrain physical processes ranging from Big Bang cosmology to the nature of the first stars to physical conditions within the interstellar medium of the Galaxy.

  17. Developing a Single-shot Polarimeter for Astronomy with Stessed-engineered Optics

    NASA Astrophysics Data System (ADS)

    Wolfe, Tristan; Stencel, Robert E.

    2017-01-01

    True single-shot polarimetry can be accomplished by utilizing a stress-engineered optic, with birefringence that varies spatially along its cross-section (Ramkhalawon et al. 2012). As light passes through such an optic, it will acquire a PSF that is unique to its polarization, providing the ability to measure all four Stokes parameters in a single image. This technique has not yet been adapted to astronomy. Our effort to do so faces several challenges, including the measurability of these PSFs for low polarizations, and through atmospheric turbulence. Current research demonstrates that low polarizations can remain measurable with the correct selection of stressed-optic and CCD parameters. Additionally, if signal is adequate (10^7 photons), then we demonstrate that turbulence does not negatively impact measurability. These results are leading toward the University of Denver's development of the first polarimeter to utilize these techniques in astronomy. This instrument will have intended applications of studying exoplanets and contributing to polarimetry surveys. The authors are grateful to the estate of William Herschel Womble for the support of astronomy at the University of Denver.

  18. The Ba II 4554 / Hβ Imaging Polarimeter for the Dutch Open Telescope

    NASA Astrophysics Data System (ADS)

    Snik, F.; Bettonvil, F. C. M.; Jägers, A. P. L.; Hammerschlag, R. H.; Rutten, R. J.; Keller, C. U.

    2006-12-01

    In order to expand the high-resolution, multi-wavelength imaging capabilities of the Dutch Open Telescope (DOT), an additional polarimetric channel based on a 80 mÅ tunable Lyot filter for Ba II 4554 and Hβ has been designed and constructed. The large atomic mass and the resulting steep line wings, make Ba II 4554 particularly suitable for the creation of photospheric Dopplergrams and Stokes-V magnetograms. The line also yields a significant degree of linear (scattering) polarization for observations near the limb of the Sun, which is modified by both horizontal and vertical weak-field topologies through the Hanle effect and hyperfine-structure level crossing. The polarimeter is based on liquid crystal variable retarders (LCVRs) as polarization modulators in combination with the Lyot filter's entrance polarizer. The tunability of the LCVRs is exploited to enable specific wavelength calibration, selection of the reference frame of linear polarization, and optimization of instrumental polarization cross-talk, which for the DOT is constant in time. With the future Ba II 4554 photospheric magnetograms, we expect to be able to discern magnetic structures of about 150 km with field strengths down to 100 G, and that Hanle-type observations can be performed at a resolution of about 1 arcsec. The range of applicability of Hβ imaging polarimetry has to be explored after installation.

  19. The Primordial Inflation Explorer (PIXIE): a nulling polarimeter for cosmic microwave background observations

    SciTech Connect

    Kogut, A.; Fixsen, D.J.; Chuss, D.T.; Dwek, E.; Moseley, S.H.; Wollack, E.J. E-mail: Dale.J.Fixsen@nasa.gov E-mail: Eliahu.Dwek-1@nasa.gov; and others

    2011-07-01

    The Primordial Inflation Explorer (PIXIE) is a concept for an Explorer-class mission to measure the gravity-wave signature of primordial inflation through its distinctive imprint on the linear polarization of the cosmic microwave background. The instrument consists of a polarizing Michelson interferometer configured as a nulling polarimeter to measure the difference spectrum between orthogonal linear polarizations from two co-aligned beams. Either input can view the sky or a temperature-controlled absolute reference blackbody calibrator. Rhe proposed instrument can map the absolute intensity and linear polarization (Stokes I, Q, and U parameters) over the full sky in 400 spectral channels spanning 2.5 decades in frequency from 30 GHz to 6 THz (1 cm to 50 μm wavelength). Multi-moded optics provide background-limited sensitivity using only 4 detectors, while the highly symmetric design and multiple signal modulations provide robust rejection of potential systematic errors. The principal science goal is the detection and characterization of linear polarization from an inflationary epoch in the early universe, with tensor-to-scalar ratio r < 10{sup −3} at 5 standard deviations. The rich PIXIE data set can also constrain physical processes ranging from Big Bang cosmology to the nature of the first stars to physical conditions within the interstellar medium of the Galaxy.

  20. Canadian Led X-ray Polarimeter Mission CXP

    NASA Technical Reports Server (NTRS)

    Kaspi, V.; Hanna, D.; Weisskopf, M.; Ramsey, B.; Ragan, K.; Vachon, B.; Elsner, R.; Heyl, J.; Pavlov, G.; Cumming, A.; Sutton, M.; Rowlands, N.

    2006-01-01

    We propose a Canadian-led X-ray Polarimetry Mission (CXP), to include a scattering X-ray Polarimeter and sensitive All-Sky X-ray Monitor (ASXM). Polarimetry would provide a new observational window on black holes, neutron stars, accretion disks and jets, and the ASXM would offer sensitive monitoring of the volatile X-ray sky. The envisioned polarimeter consists of a hollow scattering beryllium cone surrounded by an annular proportional counter, in a simple and elegant design that is reliable and low-risk. It would be sensitive in the 6-30 keV band to approx. 3% polarization in approx. 30 Galactic sources and 2 AGN in a baseline 1-yr mission, and have sensitivity greater than 10 times that of the previous X-ray polarimeter flown (NASA's OSO-8, 1975-78) for most sources. This X-ray polarimeter would tackle questions like, Do black holes spin?, How do pulsars pulse?, What is the geometry of the magnetic field in accreting neutron stars? Where and how are jets produced in microquasars and AGN?, What are the geometries of many of the most famous accretion-disk systems in the sky? This will be done using a novel and until-now unexploited technique that will greatly broaden the available observational phase space of compact objects by adding to timing and spectroscopy observations of polarization fraction and position angle as a function of energy. The All-Sky X-ray Monitor would scan for transients, both as potential targets for the polarimeter but also as a service to the worldwide astronomical community. The entire CXP mission could be flown for $40- 60M CDN, according to estimates by ComDev International, and could be built entirely in Canada. It would fall well within the CSA's SmallSat envelope and would empower the growing and dynamic Canadian High-Energy Astrophysics community with world leadership in a potentially high impact niche area.

  1. PEPSI spectro-polarimeter for the LBT

    NASA Astrophysics Data System (ADS)

    Strassmeier, Klaus G.; Hofmann, Axel; Woche, Manfred F.; Rice, John B.; Keller, Christoph U.; Piskunov, N. E.; Pallavicini, Roberto

    2003-02-01

    PEPSI (Postham Echelle Polarimetric and Spectroscopic Instrument) is to use the unique feature of the LBT and its powerful double mirror configuration to provide high and extremely high spectral resolution full-Stokes four-vector spectra in the wavelength range 450-1100nm. For the given aperture of 8.4m in single mirror mode and 11.8m in double mirror mode, and at a spectral resolution of 40,000-300,000 as designed for the fiber-fed Echelle spectrograph, a polarimetric accuracy between 10-4 and 10-2 can be reached for targets with visual magnitudes of up to 17th magnitude. A polarimetric accuracy better than 10-4 can only be reached for either targets brighter than approximately 10th magnitude together wiht a substantial trade-off wiht the spectral resolution or with spectrum deconvolution techniques. At 10-2, however, we will be able to observe the brightest AGNs down to 17th magnitude.

  2. Operation experience of p-Carbon polarimeter in RHIC

    SciTech Connect

    Huang, H.; Alekseev, I. G.; Aschenauer, E. C.; Atoian, G.; Bazilevsky, A.; Eyser, O.; Kalinkin, D.; Kewisch, J.; Makdisi, Y.; Nemesure, S.; Poblaguev, A.; Schmidke, W. B.; Svirida, D.; Steski, D.; Webb, G.; Zelenski, A.; Tip, K.

    2015-05-03

    The spin physics program in Relativistic Heavy Ion Collider (RHIC) requires fast polarimeter to monitor the polarization evolution on the ramp and during stores. Over past decade, the polarimeter has evolved greatly to improve its performance. These include dual chamber design, monitoring camera, Si detector selection (and orientation), target quality control, and target frame modification. The preamp boards have been modified to deal with the high rate problem, too. The ultra thin carbon target lifetime is a concern. Simulations have been carried out on the target interaction with beam. Modification has also been done on the frame design. Extra caution has been put on RF shielding to deal with the pickup noises from the nearby stochastic cooling kickers. This paper summarizes the recent operation performance of this delicate device.

  3. An upgraded interferometer-polarimeter system for broadband fluctuation measurements

    NASA Astrophysics Data System (ADS)

    Parke, E.; Ding, W. X.; Duff, J.; Brower, D. L.

    2016-11-01

    Measuring high-frequency fluctuations (above tearing mode frequencies) is important for diagnosing instabilities and transport phenomena. The Madison Symmetric Torus interferometer-polarimeter system has been upgraded to utilize improved planar-diode mixer technology. The new mixers reduce phase noise and allow more sensitive measurements of fluctuations at high frequency. Typical polarimeter rms phase noise values of 0.05°-0.07° are obtained with 400 kHz bandwidth. The low phase noise enables the resolution of fluctuations up to 250 kHz for polarimetry and 600 kHz for interferometry. The importance of probe beam alignment for polarimetry is also verified; previously reported tolerances of ≤0.1 mm displacement for equilibrium and tearing mode measurements minimize contamination due to spatial misalignment to within acceptable levels for chords near the magnetic axis.

  4. An ultraviolet polarimeter for the Solar Maximum Mission

    NASA Technical Reports Server (NTRS)

    Calvert, J.; Griner, D.; Montenegro, J.; Nola, F.; Rutledge, F.; Tandberg-Hanssen, E.; Wyman, C. L.; Beckers, J. M.

    1979-01-01

    The Solar Maximum Mission experiment contingency will include one instrument originally designed and built for OSO-8. The engineering model of the OSO-8 High Resolution Spectrometer has been rebuilt to make it lightworthy and to encompass several new functions, including solar ultraviolet polarimetry. The rebuilt package is designated as the High Resolution Ultraviolet Spectrometer/Polarimeter. The device that enables polarimetry is a dual channel rotating waveplate system. The waveplates are magnesium fluoride and will allow measurements to be made ranging from the Lyman alpha line to near visible ultraviolet. One wavelength channel will use the polarization characteristics of the spectrometer diffraction grating as the analyzer. The second channel has a built-in four-mirror polarizer. This paper describes the polarimeter design, operation, and calibration.

  5. A high-precision polarimeter for small telescopes

    NASA Astrophysics Data System (ADS)

    Bailey, Jeremy; Cotton, Daniel V.; Kedziora-Chudczer, Lucyna

    2017-02-01

    We describe Mini-HIPPI (Miniature HIgh Precision Polarimetric Instrument), a stellar polarimeter weighing just 650 gm but capable of measuring linear polarization to ∼10-5. Mini-HIPPI is based on the use of a Ferroelectric Liquid Crystal modulator. It can easily be mounted on a small telescope and allows us to study the polarization of bright stars at levels of precision which are hitherto largely unexplored. We present results obtained with Mini-HIPPI on a 35-cm telescope. Measurements of polarized standard stars are in good agreement with predicted values. Measurements of a number of bright stars agree well with those from other high-sensitivity polarimeters. Observations of the binary system Spica show polarization variability around the orbital cycle.

  6. A New Polarimeter at the Universite de Montreal

    NASA Astrophysics Data System (ADS)

    Manset, Nadine; Bastien, Pierre

    1995-05-01

    We present Beauty and The Beast, a new polarimeter of the Universite de Montreal, formerly built for the Canada-France-Hawaii telescope (CFHT) but never commissioned there. This computer-controlled Pockels cell polarimeter has been restored to working order and offers a wide range of possibilities: almost all functions are under remote control, linear or circular polarization observations are both possible, a filter slide provides easy access to up to six different bandpasses, and the Pockels cell and Fabry lenses are kept at a constant temperature. In addition to controlling the instrument, the software allows the use of pre-defined sequences of observation, and does data acquisition and reduction. (SECTION: Astronomical Instrumentation)

  7. Calibration and exploitation of a narrowband imaging polarimeter

    NASA Astrophysics Data System (ADS)

    Duggin, Michael J.; Loe, Richard S.

    2002-05-01

    The integration and calibration of a narrow-band imaging polarimeter is described. The system is designed to exploit subtle spectral details in visible and near-IR polarimetric images. All of the system components were commercial off the shelf. This device uses a tunable liquid crystal filter and a 16-bit cooled CCD camera. The challenges of calibrating a narrow-band imaging polarimeter are discussed. We describe examples of image data collected in the laboratory, which show that spectral polarimetric data is superior to unpolarized intensity data in facilitating the extraction of detail in shadowed regions below a vegetative canopy. In particular, we introduce a polarization-based normalized difference vegetation index (NDVI) algorithm that demonstrates significant contrast enhancement between a man-made object and a foilage background.

  8. Development of land based radar polarimeter processor system

    NASA Technical Reports Server (NTRS)

    Kronke, C. W.; Blanchard, A. J.

    1983-01-01

    The processing subsystem of a land based radar polarimeter was designed and constructed. This subsystem is labeled the remote data acquisition and distribution system (RDADS). The radar polarimeter, an experimental remote sensor, incorporates the RDADS to control all operations of the sensor. The RDADS uses industrial standard components including an 8-bit microprocessor based single board computer, analog input/output boards, a dynamic random access memory board, and power supplis. A high-speed digital electronics board was specially designed and constructed to control range-gating for the radar. A complete system of software programs was developed to operate the RDADS. The software uses a powerful real time, multi-tasking, executive package as an operating system. The hardware and software used in the RDADS are detailed. Future system improvements are recommended.

  9. Anti-Stokes shift luminescent materials for bio-applications.

    PubMed

    Zhu, Xingjun; Su, Qianqian; Feng, Wei; Li, Fuyou

    2017-02-20

    Anti-Stokes shift luminescence is a special optical process, which converts long-wavelength excitation to short-wavelength emission. This unique ability is especially helpful for bio-applications, because the longer-wavelength light source, usually referring to near infrared light, has a larger penetration depth offering a longer working distance for in vivo applications. The anti-Stokes shift luminescence signal can also be distinguished from the auto-fluorescence of biological tissues, thus reducing background interference during bioimaging. Herein, we summarize recent advances in anti-Stokes shift luminescent materials, including lanthanide and triplet-triplet-annihilation-based upconversion nanomaterials, and newly improved hot-band absorption-based luminescent materials. We focus on the synthetic strategies, optical optimization and biological applications as well as present comparative discussions on the luminescence mechanisms and characteristics of these three types of luminescent materials.

  10. MITO-Pol, a polarimeter for the Testa Grigia observatory

    NASA Astrophysics Data System (ADS)

    Maoli, R.; Savini, G.; Melchiorri, F.

    2002-05-01

    After a short review of the existing upper limits on CMB polarization and planned experiments, we present the solution adopted to resolve polarized signals with MITO-Pol, a polarimeter that will operate at the focal plane of MITO telescope. The first MITO-Pol campaign is planned for Winter 2002-2003. The main goals of this instrument are search for calibration sources and investigation of the polarization field around the CMB anisotropy peaks. .

  11. The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP)

    NASA Technical Reports Server (NTRS)

    Ishikawa, Shin-nosuke; Kano, R.; Kobayashi, K.; Bando, T.; Narukage, N..; Ishikawa, R.; Kubo, M.; Katsukawa, Y.; Suematsu, Y.; Hara, H.; Shimizu, T.; Sakao, T.; Ichimoto, K.; Giono, G.; Holloway, T.; Winebarger, A.; Cirtain, J.; DePontieu, B.; Casini, R.; Auchere F.; Bueno, J. Trujillo; Sainz, R. Manso; Belluzzi, L.; Ramos, A. Asensio; Stepan, J.; Carlsson, M.

    2014-01-01

    To Understand energy release process in the Sun including solar flares, it is essentially important to measure the magnetic field of the atmosphere of the Sun. Magnetic field measurement of the upper layers (upper chromosphere and above) was technically difficult and not well investigated yet. Upper chromosphere and transition region magnetic field measurement by Chromospheric Lyman-Alpha SpectroPolarimeter (CLASP) sounding rocket to be launched in 2015. The proposal is already selected and developments of the flight components are going.

  12. The Polarimeter for Relativistic Astrophysical X-ray Sources

    NASA Astrophysics Data System (ADS)

    Jahoda, Keith; Kallman, Timothy R.; Kouveliotou, Chryssa; Angelini, Lorella; Black, J. Kevin; Hill, Joanne E.; Jaeger, Theodore; Kaaret, Philip E.; Markwardt, Craig B.; Okajima, Takashi; Petre, Robert; Schnittman, Jeremy; Soong, Yang; Strohmayer, Tod E.; Tamagawa, Toru; Tawara, Yuzuru

    2016-07-01

    The Polarimeter for Relativistic Astrophysical X-ray Sources (PRAXyS) is one of three Small Explorer (SMEX) missions selected by NASA for Phase A study, with a launch date in 2020. The PRAXyS Observatory exploits grazing incidence X-ray mirrors and Time Projection Chamber Polarimeters capable of measuring the linear polarization of cosmic X-ray sources in the 2-10 keV band. PRAXyS combines well-characterized instruments with spacecraft rotation to ensure low systematic errors. The PRAXyS payload is developed at the Goddard Space Flight Center with the Johns Hopkins University Applied Physics Laboratory, University of Iowa, and RIKEN (JAXA) collaborating on the Polarimeter Assembly. The LEOStar-2 spacecraft bus is developed by Orbital ATK, which also supplies the extendable optical bench that enables the Observatory to be compatible with a Pegasus class launch vehicle. A nine month primary mission will provide sensitive observations of multiple black hole and neutron star sources, where theory predicts polarization is a strong diagnostic, as well as exploratory observations of other high energy sources. The primary mission data will be released to the community rapidly and a Guest Observer extended mission will be vigorously proposed.

  13. Design and Calibration of the QUIET CMB Polarimeter

    NASA Astrophysics Data System (ADS)

    Buder, Immanuel

    2011-04-01

    QUIET is a large--angular-scale Cosmic Microwave Background (CMB) polarimeter designed to measure the B-mode signal from inflation. The design incorporates a new time-stream "double-demodulation" technique, a 1.4-m Mizuguchi--Dragone telescope, natural sky rotation, and frequent boresight rotation to minimize systematic contamination. The levels of contamination in the inflationary signal are below r=0.1, the best yet achieved by any B-mode polarimeter. Moreover, QUIET is unique among B-mode polarimeters in using a large focal-plane array of miniaturized High--Electron-Mobility Transistor (HEMT) based coherent detectors. These detectors take advantage of a breakthrough in microwave-circuit packaging to achieve a field sensitivity of 69,K√s. QUIET has collected > 10,000,ours of data and recently released results from the first observing season at Q band (43 GHz). Analysis of W-band (95-GHz) data is ongoing. I will describe the Q-band calibration plan which uses a combination of astronomical and artificial sources to convert the raw data into polarization measurements with small and well-understood calibration errors. I will also give a status report on calibration for the upcoming W-band results.

  14. Multichannel interferometer/polarimeter system for the RTP tokamak

    NASA Astrophysics Data System (ADS)

    van Lammeren, A. C. A. P.; Kim, S. K.; Donné, A. J. H.

    1990-10-01

    A nine-channel interferometer/polarimeter system is designed for the RTP tokamak (Rijnhuizen Tokamak Project, a =0.16 m, R =0.72 m, BT =2.5 T, Ip ≤ 200 kA, and plasma pulse duration 200 ms). A CO2-pumped dual-cavity FIR laser system is used to obtain two FIR laser beams of λ =432 μm with a frequency difference of 1 MHz. The FIR beams are expanded by a set of parabolic mirrors. Corner-cube mixers with Schottky diodes are used as detectors. The mixers are mounted on a linear rail system, such that their positions can be easily changed. The interferometer can be operated with a maximum of 19 channels, and will be extended with a polarimeter to measure the poloidal magnetic field distribution. It will be tried to increase the accuracy of the polarimeter by modulating the polarization of the incoming beam. A scheme for polarization modulation which is based on the idea of Dodel and Kunz will be presented in this paper. This scheme has the advantage that only one set of detectors is needed to measure the electron density and current density. The complete system will be presented along with some pilot experiments concerning the polarization modulation.

  15. The Polarimeter for Relativistic Astrophysical X-ray Sources

    NASA Technical Reports Server (NTRS)

    Jahoda, Keith; Kallman, Timothy R.; Kouveliotou, Chryssa; Angelini, Lorella; Black, J. Kevin; Hill, Joanne E.; Jaeger, Theodore; Kaaret, Phillip E.; Markwardt, Craig B.; Okajima, Takashi; Petre, Robert; Schnittman, Jeremy; Soong, Yang; Strohmayer, Tod E.; Tamagawa, Toru; Tawara, Yuzuru

    2016-01-01

    The Polarimeter for Relativistic Astrophysical X-ray Sources (PRAXyS) is one of three Small Explorer (SMEX) missions selected by NASA for Phase A study, with a launch date in 2020. The PRAXyS Observatory exploits grazing incidence X-ray mirrors and Time Projection Chamber Polarimeters capable of measuring the linear polarization of cosmic X-ray sources in the 2-10 keV band. PRAXyS combines well-characterized instruments with spacecraft rotation to ensure low systematic errors. The PRAXyS payload is developed at the Goddard Space Flight Center with the Johns Hopkins University Applied Physics Laboratory, University of Iowa, and RIKEN (JAXA) collaborating on the Polarimeter Assembly. The LEOStar-2 spacecraft bus is developed by Orbital ATK, which also supplies the extendable optical bench that enables the Observatory to be compatible with a Pegasus class launch vehicle. A nine month primary mission will provide sensitive observations of multiple black hole and neutron star sources, where theory predicts polarization is a strong diagnostic, as well as exploratory observations of other high energy sources. The primary mission data will be released to the community rapidly and a Guest Observer extended mission will be vigorously proposed.

  16. Simple modification of Compton polarimeter to redirect synchrotron radiation

    NASA Astrophysics Data System (ADS)

    Benesch, J.; Franklin, G. B.; Quinn, B. P.; Paschke, K. D.

    2015-11-01

    Synchrotron radiation produced as an electron beam passes through a bending magnet is a significant source of background in many experiments. Using modeling, we show that simple modifications of the magnet geometry can reduce this background by orders of magnitude in some circumstances. Specifically, we examine possible modifications of the four dipole magnets used in Jefferson Lab's Hall A Compton polarimeter chicane. This Compton polarimeter has been a crucial part of experiments with polarized beams and the next generation of experiments will utilize increased beam energies, up to 11 GeV, requiring a corresponding increase in Compton dipole field to 1.5 T. In consequence, the synchrotron radiation (SR) from the dipole chicane will be greatly increased. Three possible modifications of the chicane dipoles are studied; each design moves about 2% of the integrated bending field to provide a gentle bend in critical regions along the beam trajectory which, in turn, greatly reduces the synchrotron radiation within the acceptance of the Compton polarimeter photon detector. Each of the modifications studied also softens the SR energy spectrum at the detector sufficiently to allow shielding with 5 mm of lead. Simulations show that these designs are each capable of reducing the background signal due to SR by three orders of magnitude. The three designs considered vary in their need for vacuum vessel changes and in their effectiveness.

  17. Terrace retro-reflector array for poloidal polarimeter on ITER.

    PubMed

    Imazawa, R; Kawano, Y; Ono, T; Kusama, Y

    2011-02-01

    A new concept of a terrace retro-reflector array (TERRA) as part of the poloidal polarimeter for ITER is proposed in this paper. TERRA reflects a laser light even from a high incident angle in the direction of the incident-light path, while a conventional retro-reflector array cannot. Besides, TERRA can be installed in a smaller space than a corner-cube retro-reflector. In an optical sense, TERRA is equivalent to a Littrow grating, the blaze angle of which varies, depending on the incident angle. The reflected light generates a bright and dark fringe, and the bright fringe is required to travel along the incident-light path to achieve the objects of laser-aided diagnostics. In order to investigate the propagation properties of laser light reflected by TERRA, we have developed a new diffraction formula. Conditions for the propagation of the bright fringe in the direction of the incident light have been obtained using the Littrow grating model and have been confirmed in a simulation applying the new diffraction formula. Finally, we have designed laser transmission optics using TERRA for the ITER poloidal polarimeter and have calculated the light propagation of the system. The optical design obtains a high transmission efficiency, with 88.6% of the incident power returned. These results demonstrate the feasibility of applying TERRA to the ITER poloidal polarimeter.

  18. Calibration of the stellar X-ray polarimeter

    SciTech Connect

    Tomsick, J.

    1997-07-01

    The Stellar X-Ray Polarimeter (SXRP) will be more than an order of magnitude more sensitive than any previous x-ray polarimeter in the 2-15 keV energy band. The SXRP is a focal plane detector for a Danish-Russian SODART telescope, which will be launched on the Russian Spectrum-X-Gamma (SXG) mission. The SXRP exploits the polarization dependence of Bragg reflection from a graphite crystal, and of Thomson scattering from a target of metallic lithium. The SXRP flight model (FM) was calibrated at a facility at Lawrence Livermore National Laboratory (LLNL) equipped with polarized and unpolarized x-ray sources producing x-rays in the band pass for the graphite and the lithium scatterers. By adjusting the orientation of the SXRP with respect to the incident x-ray beam, it was possible to simulate the converging beam from a SODART telescope and to measure the SXRP response to telescope pointing errors. In this paper we describe the SXRP-FM calibration and present results for the graphite polarimeter.

  19. Spectrographic Polarimeter and Method of Recording State of Polarity

    NASA Technical Reports Server (NTRS)

    Sparks, William B. (Inventor)

    2015-01-01

    A single-shot real-time spectropolarimeter for use in astronomy and other sciences that captures and encodes some or all of the Stokes polarization parameters simultaneously using only static, robust optical components with no moving parts is described. The polarization information is encoded onto the spectrograph at each wavelength along the spatial dimension of the 2D output data array. The varying embodiments of the concept include both a two-Stokes implementation (in which any two of the three Stokes polarization parameters are measured) and a full Stokes implementation (in which all three of the Stokes polarization parameters are measured), each of which is provided in either single beam or dual beam forms.

  20. GDx-MM: An imaging Mueller matrix retinal polarimeter

    NASA Astrophysics Data System (ADS)

    Twietmeyer, Karen Marie

    2007-12-01

    Retinal diseases are a major cause of blindness worldwide. Although widely studied, disease mechanisms are not completely understood, and diagnostic tests may not detect disease early enough for timely intervention. The goal of this research is to contribute to research for more sensitive diagnostic tests that might use the interaction of polarized light with retinal tissue to detect subtle changes in the microstructure. This dissertation describes the GDx-MM, a scanning laser polarimeter which measures a complete 16-element Mueller matrix image of the retina. This full polarization signature may provide new comparative information on the structure of healthy and diseased retinal tissue by highlighting depolarizing structures as well as structures with varying magnitudes and orientations of retardance and diattenuation. The three major components of this dissertation are: (1) Development of methods for polarimeter optimization and error analysis; (2) Design, optimization, assembly, calibration, and validation of the GDx-MM polarimeter; and (3) Analysis of data for several human subjects. Development involved modifications to a Laser Diagnostics GDx, a commercially available scanning laser ophthalmoscope with incomplete polarization capability. Modifications included installation of polarization components, development of a data acquisition system, and implementation of algorithms to convert raw data into polarization parameter images. Optimization involved visualization of polarimeter state trajectories on the Poincare sphere and a condition number analysis of the instrument matrix. Retinal images are collected non-invasively at 20 mum resolution over a 15° visual field in four seconds. Validation of the polarimeter demonstrates a polarimetric measurement accuracy of approximately +/- 5%. Retinal polarization data was collected on normal human subjects at the University of Arizona and at Indiana University School of Optometry. Calculated polarization parameter

  1. FPGA-Based X-Ray Detection and Measurement for an X-Ray Polarimeter

    NASA Technical Reports Server (NTRS)

    Gregory, Kyle; Hill, Joanne; Black, Kevin; Baumgartner, Wayne

    2013-01-01

    This technology enables detection and measurement of x-rays in an x-ray polarimeter using a field-programmable gate array (FPGA). The technology was developed for the Gravitational and Extreme Magnetism Small Explorer (GEMS) mission. It performs precision energy and timing measurements, as well as rejection of non-x-ray events. It enables the GEMS polarimeter to detect precisely when an event has taken place so that additional measurements can be made. The technology also enables this function to be performed in an FPGA using limited resources so that mass and power can be minimized while reliability for a space application is maximized and precise real-time operation is achieved. This design requires a low-noise, charge-sensitive preamplifier; a highspeed analog to digital converter (ADC); and an x-ray detector with a cathode terminal. It functions by computing a sum of differences for time-samples whose difference exceeds a programmable threshold. A state machine advances through states as a programmable number of consecutive samples exceeds or fails to exceed this threshold. The pulse height is recorded as the accumulated sum. The track length is also measured based on the time from the start to the end of accumulation. For track lengths longer than a certain length, the algorithm estimates the barycenter of charge deposit by comparing the accumulator value at the midpoint to the final accumulator value. The design also employs a number of techniques for rejecting background events. This innovation enables the function to be performed in space where it can operate autonomously with a rapid response time. This implementation combines advantages of computing system-based approaches with those of pure analog approaches. The result is an implementation that is highly reliable, performs in real-time, rejects background events, and consumes minimal power.

  2. A Cadmium telluride micro-Spectometers Hard X ray Polarimeter for a balloon borne payload

    NASA Astrophysics Data System (ADS)

    Caroli, Ezio; Hernanz, Margarita; Ferrando, Philippe; Del Sordo, Stefano; Stephen, John; Laurent, Philippe; Alvarez, Jose M.; Auricchio, Natalia; Budtz-Jorgensen, Carl; Curado da Silva4, Rui M.; Limousin, Olivier; Galvez, Jose L.; Gloster, Paul Colin; Isern, Jordi; Maia, Jorge M.

    2012-07-01

    In the next generation of space instrumentation for hard X-ray astrophysics, the measurement of the polarization status of cosmic sources will be a key observational parameter in order to help understand the various production mechanisms and the source geometry. As polarisation observations are very difficult to perform, new telescopes operating in this energy range should be optimized for this type of measurement. In this perspective, we present the concept of a small high-performance spectrometer designed to operate as a scattering polarimeter between 100 and 500 keV and suitable for a stratospheric balloon-borne payload: CμSP (Cadmium telluride μ-Spectrometers Polarimeter). This instrument will be dedicated to perform an accurate and reliable measurement of the polarization status of the Crab pulsar, i.e. the polarization level and direction. The detector with 3D spatial resolution is made of CZT spectrometers in a highly segmented configuration in order to enhance as much as possible the sensitivity to the linear polarisation of detected photons. We discuss different configurations based on recent development results as well as possible improvements under study. Furthermore we describe a possible baseline design of the payload, which can also be seen as a pathfinder for a high performance detector for the next generation of hard X and soft gamma ray telescopes based on high energy focussing optics (e.g. Laue lenses) and/or advanced Compton instruments. Finally, we present Monte Carlo evaluations of the achievable sensitivity to polarisation as a function of different detector characteristics.

  3. Identification of errors in the electron density measurements of a tangential interferometer/polarimeter system during a tokamak discharge

    SciTech Connect

    Arakawa, H.; Kawano, Y.; Itami, K.

    2012-10-15

    A new method for the comparative verification of electron density measurements obtained with a tangential interferometer and a polarimeter during a discharge is proposed. The possible errors associated with the interferometer and polarimeter are classified by the time required for their identification. Based on the characteristics of the errors, the fringe shift error of the interferometer and the low-frequency noise of the polarimeter were identified and corrected for the JT-60U tangential interferometer/polarimeter system.

  4. A New Cost-Effective Diode Laser Polarimeter Apparatus Constructed by Undergraduate Students

    ERIC Educational Resources Information Center

    Lisboa, Pedro; Sotomayor, Joo; Ribeiro, Paulo

    2010-01-01

    The construction of a diode laser polarimeter apparatus by undergraduate students is described. The construction of the modular apparatus by undergraduate students gives them an insight into how it works and how the measurement of a physical or chemical property is conducted. The students use the polarimeter to obtain rotation angle values for the…

  5. A Shoebox Polarimeter: An Inexpensive Analytical Tool for Teachers and Students

    ERIC Educational Resources Information Center

    Mehta, Akash; Greenbowe, Thomas J.

    2011-01-01

    A polarimeter can determine the optical activity of an organic or inorganic compound by providing information about the optical rotation of plane-polarized light when transmitted through that compound. This "Journal" has reported various construction methods for polarimeters. We report a unique construction using a shoebox, recycled office…

  6. The science case of the PEPSI high-resolution echelle spectrograph and polarimeter for the LBT

    NASA Astrophysics Data System (ADS)

    Strassmeier, K. G.; Pallavicini, R.; Rice, J. B.; Andersen, M. I.

    2004-05-01

    We lay out the scientific rationale for and present the instrumental requirements of a high-resolution adaptive-optics Echelle spectrograph with two full-Stokes polarimeters for the Large Binocular Telescope (LBT) in Arizona. Magnetic processes just like those seen on the Sun and in the space environment of the Earth are now well recognized in many astrophysical areas. The application to other stars opened up a new field of research that became widely known as the solar-stellar connection. Late-type stars with convective envelopes are all affected by magnetic processes which give rise to a rich variety of phenomena on their surface and are largely responsible for the heating of their outer atmospheres. Magnetic fields are likely to play a crucial role in the accretion process of T-Tauri stars as well as in the acceleration and collimation of jet-like flows in young stellar objects (YSOs). Another area is the physics of active galactic nucleii (AGNs) , where the magnetic activity of the accreting black hole is now believed to be responsible for most of the behavior of these objects, including their X-ray spectrum, their notoriously dramatic variability, and the powerful relativistic jets they produce. Another is the physics of the central engines of cosmic gamma-ray bursts, the most powerful explosions in the universe, for which the extreme apparent energy release are explained through the collimation of the released energy by magnetic fields. Virtually all the physics of magnetic fields exploited in astrophysics is somehow linked to our understanding of the Sun's and the star's magnetic fields.

  7. Variation in sunspot properties between 1999 and 2011 as observed with the Tenerife Infrared Polarimeter

    NASA Astrophysics Data System (ADS)

    Rezaei, R.; Beck, C.; Schmidt, W.

    2012-05-01

    Aims: We study the variation in the magnetic field strength and the umbral intensity of sunspots during the declining phase of the solar cycle No. 23 and in the beginning of cycle No. 24. Methods: We analyze a sample of 183 sunspots observed from 1999 until 2011 with the Tenerife Infrared Polarimeter (TIP) at the German Vacuum Tower Telescope (VTT). The magnetic field strength is derived from the Zeeman splitting of the Stokes-V signal in one near-infrared spectral line, either Fe i 1564.8 nm, Fe i 1089.6 nm, or Si i 1082.7 nm. This avoids the effects of the unpolarized stray light from the field-free quiet Sun surroundings that can affect the splitting seen in Stokes-I in the umbra. The minimum umbral continuum intensity and umbral area are also measured. Results: We find that there is a systematic trend for sunspots in the late stage of the solar cycle No. 23 to be weaker, i.e., to have a smaller maximum magnetic field strength than those at the start of the cycle. The decrease in the field strength with time of about 94 Gyr-1 is well beyond the statistical fluctuations that would be expected because of the larger number of sunspots close to cycle maximum (14 Gyr-1). In the same time interval, the continuum intensity of the umbra increases with a rate of 1.3 (±0.4)% of Ic yr-1, while the umbral area does not show any trend above the statistical variance. Sunspots in the new cycle No. 24 show higher field strengths and lower continuum intensities than those at the end of cycle No. 23, interrupting the trend. Conclusions: Sunspots have an intrinsically weaker field strength and brighter umbrae at the late stages of solar cycles compared to their initial stages, without any significant change in their area. The abrupt increase in field strength in sunspots of the new cycle suggests that the cyclic variations are dominating over any long-term trend that continues across cycles. We find a slight decrease in field strength and an increase in intensity as a long

  8. The x-ray polarimeter instrument on board the Polarimeter for Relativistic Astrophysical X-ray Sources (PRAXyS) mission

    NASA Astrophysics Data System (ADS)

    Hill, J. E.; Black, J. K.; Jahoda, K.; Tamagawa, T.; Iwakiri, W.; Kitaguchi, T.; Kubota, M.; Kaaret, P.; McCurdy, R.; Miles, D. M.; Okajima, T.; Soong, Y.; Olsen, L.; Sparr, L.; Mosely, S. J.; Nolan, D.

    2016-07-01

    The Polarimeter for Relativistic Astrophysical X-ray Sources (PRAXyS) is one of three Small Explorer (SMEX) missions selected by NASA for Phase A study. The PRAXyS observatory carries an X-ray Polarimeter Instrument (XPI) capable of measuring the linear polarization from a variety of high energy sources, including black holes, neutron stars, and supernova remnants. The XPI is comprised of two identical mirror-Time Projection Chamber (TPC) polarimeter telescopes with a system effective area of 124 cm2 at 3 keV, capable of photon limited observations for sources as faint as 1 mCrab. The XPI is built with well-established technologies. This paper will describe the performance of the XPI flight mirror with the engineering test unit polarimeter.

  9. Dual instrument for Flare and CME onset observations - Double solar Coronagraph with Solar Chromospheric Detector and Coronal Multi-channel Polarimeter at Lomnicky stit Observatory

    NASA Astrophysics Data System (ADS)

    Kucera, Ales; Tomczyk, Steven; Rybak, Jan; Sewell, Scott; Gomory, Peter; Schwartz, Pavol; Ambroz, Jaroslav; Kozak, Matus

    2015-08-01

    We report on unique dual instrument developed for simultaneous measurements of velocity and magnetic fields in the solar chromosphere and corona. We describe the technical parameters and capability of the Coronal Multi-channel Polarimeter (CoMP-S) and Solar Chromospheric detector (SCD) mounted at the Double solar coronagraph at Lomnicky Stit Observatory and working simultaneously with strictly parallel pointing of both coronagraphs. The CoMP-S is 2D spectropolarimeter designed for observations of VIS and near-IR emission lines of prominences and corona with operating spectral range: 500 - 1100 nm, sequential measurement of several VIS and near-IR lines. Its field of view is 14 arcmin x 11 arcmin. It consists of 4-stage calcite Lyot filter followed by the ferro-liquid crystal polarizer and four cameras (2 visible, 2 infrared). The capability is to deliver 2D full Stokes I, Q, U, V, using registration with 2 IR cameras (line + background) and 2 VIS cameras (line + background) SCD is a single beam instrument to observe bright chromosphere. It is a combination of tunable filter and polarimeter. Spectral resolution of the SCD ranges from 0.046 nm for observations of the HeI 1083 nm line up to to 25 pm is for observation of the HeI 587.6 nm line. The birefringent filter of the SCD has high spectral resolution, as well as spatial resolution (1.7 arcseconds) and temporal resolution (10 seconds) First results are also reported and discussed.

  10. Self-referenced, microdegree, optical rotation polarimeter for biomedical applications: an analysis

    NASA Astrophysics Data System (ADS)

    Weissman, Zeev; Goldberg, Doron

    2016-07-01

    We comprehensively analyze the performance of a type of optical rotation (OR) polarimeter, which has been designed from the outset to fit the special requirements of two major applications: general chiral detection during the separation of optical isomers by high-pressure liquid chromatography systems in the pharmaceutical industry, and monitoring of glucose in the interstitial fluid of diabetics by a fully implanted long-term optical sensor. Both very demanding applications call for an OR polarimeter that can be miniaturized while maintaining high resolution and accuracy in the microdegree range in the face of considerable noise from various sources. These two characteristics-miniature size and immunity to noise-set this polarimeter apart from the traditional OR polarimeters currently in use, which are both bulky and very susceptible to noise. The following detailed analysis demonstrates the advantages of this polarimeter and its potential as an analytic and diagnostic tool.

  11. Full Stokes observations in the He i 1083 nm spectral region covering an M3.2 flare

    NASA Astrophysics Data System (ADS)

    Kuckein, Christoph; Collados, Manuel; Sainz, Rafael Manso; Ramos, Andrés Asensio

    2015-10-01

    We present an exceptional data set acquired with the Vacuum Tower Telescope (Tenerife, Spain) covering the pre-flare, flare, and post-flare stages of an M3.2 flare. The full Stokes spectropolarimetric observations were recorded with the Tenerife Infrared Polarimeter in the He i 1083.0 nm spectral region. The object under study was active region NOAA 11748 on 2013 May 17. During the flare the chomospheric He i 1083.0 nm intensity goes strongly into emission. However, the nearby photospheric Si i 1082.7 nm spectral line profile only gets shallower and stays in absorption. Linear polarization (Stokes Q and U) is detected in all lines of the He i triplet during the flare. Moreover, the circular polarization (Stokes V) is dominant during the flare, being the blue component of the He i triplet much stronger than the red component, and both are stronger than the Si i Stokes V profile. The Si i inversions reveal enormous changes of the photospheric magnetic field during the flare. Before the flare magnetic field concentrations of up to ~1500 G are inferred. During the flare the magnetic field strength globally decreases and in some cases it is even absent. After the flare the magnetic field recovers its strength and initial configuration.

  12. On testing of the photometer-polarimeter UVP layout using a telescope on Earth's surface

    NASA Astrophysics Data System (ADS)

    Nevodovskyi, P. V.; Vidmachenko, A. P.; Morozhenko, O. V.; Zbrutskyi, O.; Ivakhiv, O. V.

    2016-08-01

    One of the causes of climate change (changing of concentration of stratospheric ozone) - is variations due to aerosol optical thickness in the upper layers of Earth's atmosphere. To solve the problem is necessary to make a space experiment to receive polarization observational data. Their analysis will: determine the value of the real part of the refractive index, the size of the stratospheric aerosol, optical thickness of the stratospheric aerosol layer, investigate aerosol's layer horizontal structure and its changes over time. Main Astronomical Observatory of NAS of Ukraine jointly with the National Technical University of Ukraine "KPI" and National University "Lviv Polytechnic" for a long time working on the design of polarimeter to study the stratospheric layer of the Earth from board of artificial satellites. During this time accumulated a great experience in such work, and created a layout of compact board ultraviolet polarimeter UFP [1-4]. For testing of ground variant of layout of UFP, it is installed on the telescope AZT-2 of the Main Astronomical Observatory NAS of Ukraine (Kyiv). Using it we plan to investigate the possibility of determining the degree of polarization of the twilight glow of Earth's atmosphere, and implementation of this technique in the development of space experiment on investigation of the stratospheric aerosol from space. For this purpose we develop a special set of equipment that will adapt the layout for working of UFP with telescope AZT-2, and carry out the above mentioned work (see. in [5-7]). References. 1. P. Nevodovskyi, O. Morozhenko, A. Vidmachenko, O. Ivakhiv, M. Geraimchuk, O. Zbrutskyi. Tiny Ultraviolet Polarimeter for Earth Stratosphere from Space Investigation // Proceedings of 8th IEEE International Conference on Intelligent Data Acquisition and Advanced Computing Systems: Technology and Applications (IDAACS'2015). 24-26 September 2015, Proceedings. Warsaw, Poland. Vol.81, p. 28-32. 2. Nevodovsksiy P. V., Morozhenko A

  13. [Adrian Stokes and 'trench jaundice'].

    PubMed

    Wever, Peter C

    2015-01-01

    On the day that Great Britain declared war on Germany in 1914, the Irish physician and bacteriologist Adrian Stokes travelled to London to volunteer. One week later he left for France with the first British troops as an officer with the Royal Army Medical Corps. He spent most of the First World War attached to No. 1 Mobile Bacteriological Laboratory at the Remy Siding British-Canadian field hospital in Flanders. In April 1916, he was confronted with an outbreak of trench jaundice, also known as epidemic jaundice (Weil's disease). Conditions in the trenches contributed to the hundred cases identified by Stokes in a short period. In 1917, he was the first to publish (in The Lancet) the finding that the bacterium Spirochaeta icterohaemorrhagiae, the causative agent of epidemic jaundice, could be isolated from the kidneys of rats. A subsequent rat control campaign in the trenches successfully curbed the disease.

  14. Navier Stokes Theorem in Hydrology

    NASA Astrophysics Data System (ADS)

    Narayanan, M.

    2005-12-01

    In a paper presented at the 2004 AGU International Conference, the author outlined and stressed the importance of studying and teaching certain important mathematical techniques while developing a course in Hydrology and Fluid Mechanics. The Navier-Stokes equations are the foundation of fluid mechanics, and Stokes' theorem is used in nearly every branch of mechanics as well as electromagnetics. Stokes' Theorem also plays a vital role in many secondary theorems such as those pertaining to vorticity and circulation. Mathematically expressed, Stokes' theorem can be expressed by considering a surface S having a bounding curve C. Here, V is any sufficiently smooth vector field defined on the surface and its bounding curve C. In an article entitled "Corrections to Fluid Dynamics" R. F. Streater, (Open Systems and Information Dynamics, 10, 3-30, 2003.) proposes a kinetic model of a fluid in which five macroscopic fields, the mass, energy, and three components of momentum, are conserved. The dynamics is constructed using the methods of statistical dynamics, and results in a non-linear discrete-time Markov chain for random fields on a lattice. In the continuum limit he obtains a non-linear coupled parabolic system of field equations, showing a correction to the Navier-Stokes equations. In 2001, David Hoff published an article in Journees Equations aux derivees partielles. (Art. No. 7, 9 p.). His paper is entitled : Dynamics of Singularity Surfaces for Compressible Navier-Stokes Flows in Two Space Dimensions. In his paper, David Hoff proves the global existence of solutions of the Navier-Stokes equations of compressible, barotropic flow in two space dimensions with piecewise smooth initial data. These solutions remain piecewise smooth for all time, retaining simple jump discontinuities in the density and in the divergence of the velocity across a smooth curve, which is convected with the flow. The strengths of these discontinuities are shown to decay exponentially in time

  15. Division of focal plane polarimeter-based 3 × 4 Mueller matrix microscope: a potential tool for quick diagnosis of human carcinoma tissues

    NASA Astrophysics Data System (ADS)

    Chang, Jintao; He, Honghui; Wang, Ye; Huang, Yi; Li, Xianpeng; He, Chao; Liao, Ran; Zeng, Nan; Liu, Shaoxiong; Ma, Hui

    2016-05-01

    A polarization microscope is a useful tool to reveal the optical anisotropic nature of a specimen and can provide abundant microstructural information about samples. We present a division of focal plane (DoFP) polarimeter-based polarization microscope capable of simultaneously measuring both the Stokes vector and the 3×4 Mueller matrix with an optimal polarization illumination scheme. The Mueller matrix images of unstained human carcinoma tissue slices show that the m24 and m34 elements can provide important information for pathological observations. The characteristic features of the m24 and m34 elements can be enhanced by polarization staining under illumination by a circularly polarized light. Hence, combined with a graphics processing unit acceleration algorithm, the DoFP polarization microscope is capable of real-time polarization imaging for potential quick clinical diagnoses of both standard and frozen slices of human carcinoma tissues.

  16. HIRES the high-resolution spectrograph for the E-ELT: dynamics and control of the repositioning mechanism for the E-ELT HIRES polarimeter

    NASA Astrophysics Data System (ADS)

    Di Varano, I.; Strassmeier, K. G.; Woche, M.

    2016-08-01

    A full Stokes dual channel polarimeter for the E-ELT HIRES spectrograph has been envisioned for the intermediate focus f/4.4, operating within a spectral range of 0.4-1.6 μ. It will feed the EELT- HIRES instrument located on the Nasmyth platform via two pairs of dedicated fibers: one fibre pair optimized for the BVRI, the other one optimized for the JH band or any other feasible combination. The instrument must be retractable within a workspace in fulfillment with the ESO requirements on the allocated volume and the dynamic response of the AO tower. For such purpose a swinging arm has been designed with a rotation provided by 5 revolute joints and a jackscrew. Moreover repeatability in repositioning has to be guaranteed by a parallel manipulator, performing an alignment procedure mainly along 5 axes. Dynamics and control criteria with a feed forward chain to compensate for vibration forces and feedback chain for tracking procedure are hereafter presented.

  17. Comment on Modified Stokes Parameters

    NASA Technical Reports Server (NTRS)

    Le Vine, D.M.; Utku, C.

    2009-01-01

    It is common practice in passive microwave remote sensing (microwave radiometry) to express observables as temperatures and in the case of polarimetric radiometry to use what are called "Modified Stokes Parameters in Brightness Temperature" to describe the scene. However, definitions with slightly different normalization (with and without division by bandwidth) have appeared in the literature. The purpose of this manuscript is to present an analysis to clarify the meaning of terms in the definition and resolve the question of the proper normalization.

  18. A cylindrically symmetric "micro-Mott" electron polarimeter

    NASA Astrophysics Data System (ADS)

    Clayburn, N. B.; Brunkow, E.; Burtwistle, S. J.; Rutherford, G. H.; Gay, T. J.

    2016-05-01

    A small, novel, cylindrically symmetric Mott electron polarimeter is described. The effective Sherman function, Seff, or analyzing power, for 20 kV Au target bias with a 1.3 keV energy loss window is 0.16 ± 0.01, where uncertainty in the measurement is due primarily to uncertainty in the incident electron polarization. For an energy loss window of 0.5 keV, Seff reaches its maximum value of 0.24 ± 0.02. The device's maximum efficiency, I/Io, defined as the detected count rate divided by the incident particle rate, is 3.7 ± 0.2 × 10-4 at 20 keV. The figure-of-merit of the device, η, is defined as Seff2I/Io and equals 9.0 ± 1.6 × 10-6. Potential sources of false asymmetries due to detector electronic asymmetry and beam misalignment have been investigated. The new polarimeter's performance is compared to published results for similar compact retarding-field Mott polarimeters, and it is concluded that this device has a relatively large Seff and low efficiency. SIMION® electron trajectory simulations and Sherman function calculations are presented to explain the differences in performance between this device and previous designs. This design has an Seff that is insensitive to spatial beam fluctuations and, for an energy loss window >0.5 keV, negligible background due to spurious ion and X-ray production at the target.

  19. Stokes solitons in optical microcavities

    NASA Astrophysics Data System (ADS)

    Yang, Qi-Fan; Yi, Xu; Yang, Ki Youl; Vahala, Kerry

    2017-01-01

    Solitons are wave packets that resist dispersion through a self-induced potential well. They are studied in many fields, but are especially well known in optics on account of the relative ease of their formation and control in optical fibre waveguides. Besides their many interesting properties, solitons are important to optical continuum generation, in mode-locked lasers, and have been considered as a natural way to convey data over great distances. Recently, solitons have been realized in microcavities, thereby bringing the power of microfabrication methods to future applications. This work reports a soliton not previously observed in optical systems, the Stokes soliton. The Stokes soliton forms and regenerates by optimizing its Raman interaction in space and time within an optical potential well shared with another soliton. The Stokes and the initial soliton belong to distinct transverse mode families and benefit from a form of soliton trapping that is new to microcavities and soliton lasers in general. The discovery of a new optical soliton can impact work in other areas of photonics, including nonlinear optics and spectroscopy.

  20. Hard X-ray Imaging Polarimeter for PolariS

    NASA Astrophysics Data System (ADS)

    Hayashida, Kiyoshi

    2016-07-01

    We present the current status of development of hard X-ray imaging polarimeters for the small satellite mission PolariS. The primary aim of PolariS is hard X-ray (10-80keV) polarimetry of sources brighter than 10mCrab. Its targets include stellar black holes, neutron stars, super nova remnants, and active galactic nuclei. This aim is enabled with three sets of hard X-ray telescopes and imaging polarimeters installed on their focal planes. The imaging polarimeter consists of two kinds of (plastic and GSO) scintillator pillars and multi-anode photo multiplier tubes (MAPMTs). When an X-ray photon incident to a plastic scintillator cause a Compton scattering, a recoiled electron makes a signal on the corresponding MAPMT pixel, and a scatted X-rays absorbed in surrounding GSO makes another signal. This provide information on the incident position and the scattered direction. The latter information is employed for polarimetry. For 20keV X-ray incidence, the recoiled electron energy is as low as 1keV. Thus, the performance of this imaging polarimeter is primarily determined by the efficiency that we can detect low level signal of recoiled electrons generated in plastic scintillators. The efficiency could depend on multiple factors, e.g. quenching of light in scintillators, electric noise, pedestal error, cross talk of the lights to adjacent MAPMT pixels, MAPMT dark current etc. In this paper, we examined these process experimentally and optimize the event selection algorithm, in which single photo-electron events are selected. We then performed an X-ray (10-80keV monochromatic polarized beam) irradiation test at a synchrotron facility. The modulation contrast (M) is about 60% in 15-80keV range. We succeeded in detecting recoiled electrons for 10-80keV X-ray incidence, though detection efficiency is lower at lowest end of the energy range. Expected MDP will also be shown.

  1. Fast full 4x4 Mueller polarimeter for endoscopic applications

    NASA Astrophysics Data System (ADS)

    Rivet, Sylvain; Bradu, Adrian; Podoleanu, Adrian

    2016-03-01

    A new set-up is proposed to measure the full polarimetric properties of a sample through an optical fiber, paving the way to full-Mueller endoscopic imaging. The technique combines a channeled spectrum polarimeter and an interferometer. This permits high-speed measurement of two Mueller matrices simultaneoulsy. The first matrix characterizes only the fiber while the second characterizes both fiber and sample. The instrument is validated on vacuum, a quarter-wave plate and a linear polarizer for single-point measurements. Insensitivity of the polarimetric measurement to fiber disturbances is proven while manipulating the fiber.

  2. Pedestal magnetic field measurements using a motional Stark effect polarimeter.

    PubMed

    Lanctot, M J; Holcomb, C T; Allen, S L; Fenstermacher, M E; Luce, T C

    2012-10-01

    Temperature-controlled, 0.15 nm interference filters were installed on an edge-viewing system of the motional Stark effect (MSE) polarimeter on the DIII-D tokamak. The upgraded system provides a factor of two reduction in the bandpass compared to the previous design, and linear control of the bandpass, which is unaltered by wavelength tuning. With the new system, there is a reduced dependence of the inferred polarization angle on the filter wavelength calibration. Recent measurements from the calibrated edge-viewing system show increased agreement with other MSE arrays.

  3. Tiny Ultraviolet Polarimeter for Earth Stratosphere from Space Investigation

    NASA Astrophysics Data System (ADS)

    Nevodovskyi, P. V.; Morozhenko, O. V.; Vidmachenko, A. P.; Ivakhiv, O.; Geraimchuk, M.; Zbrutskyi, O.

    2015-09-01

    One of the reasons for climate change (i.e., stratospheric ozone concentrations) is connected with the variations in optical thickness of aerosols in the upper sphere of the atmosphere (at altitudes over 30 km). Therefore, aerosol and gas components of the atmosphere are crucial in the study of the ultraviolet (UV) radiation passing upon the Earth. Moreover, a scrupulous study of aerosol components of the Earth atmosphere at an altitude of 30 km (i.e., stratospheric aerosol), such as the size of particles, the real part of refractive index, optical thickness and its horizontal structure, concentration of ozone or the upper border of the stratospheric ozone layer is an important task in the research of the Earth climate change. At present, the Main Astronomical Observatory of the National Academy of Sciences (NAS) of Ukraine, the National Technical University of Ukraine "KPI"and the Lviv Polytechnic National University are engaged in the development of methodologies for the study of stratospheric aerosol by means of ultraviolet polarimeter using a microsatellite. So fare, there has been created a sample of a tiny ultraviolet polarimeter (UVP) which is considered to be a basic model for carrying out space experiments regarding the impact of the changes in stratospheric aerosols on both global and local climate.

  4. Liquid Water Cloud Properties During the Polarimeter Definition Experiment (PODEX)

    NASA Technical Reports Server (NTRS)

    Alexandrov, Mikhail D.; Cairns, Brian; Wasilewski, Andrzei P.; Ackerman, Andrew S.; McGill, Matthew J.; Yorks, John E.; Hlavka, Dennis L.; Platnick, Steven; Arnold, George; Van Diedenhoven, Bastiaan; Chowdhary, Jacek; Ottaviani, Matteo; Knobelspiesse, Kirk D.

    2015-01-01

    We present retrievals of water cloud properties from the measurements made by the Research Scanning Polarimeter (RSP) during the Polarimeter Definition Experiment (PODEX) held between January 14 and February 6, 2013. The RSP was onboard the high-altitude NASA ER-2 aircraft based at NASA Dryden Aircraft Operation Facility in Palmdale, California. The retrieved cloud characteristics include cloud optical thickness, effective radius and variance of cloud droplet size distribution derived using a parameter-fitting technique, as well as the complete droplet size distribution function obtained by means of Rainbow Fourier Transform. Multi-modal size distributions are decomposed into several modes and the respective effective radii and variances are computed. The methodology used to produce the retrieval dataset is illustrated on the examples of a marine stratocumulus deck off California coast and stratus/fog over California's Central Valley. In the latter case the observed bimodal droplet size distributions were attributed to two-layer cloud structure. All retrieval data are available online from NASA GISS website.

  5. Simultaneous rotational coherent anti-Stokes Raman spectroscopy and coherent Stokes Raman spectroscopy with arbitrary pump-Stokes spectral separation.

    PubMed

    Eckbreth, A C; Anderson, T J

    1986-08-01

    A new approach to pure rotational coherent anti-Stokes Raman spectroscopy (CARS) and coherent Stokes Raman spectroscopy (CSRS) is demonstrated in which the pump and broadband Stokes lasers that are mixed have a large and arbitrary spectral separation. In this method, the rotational Raman coherences are established by different frequency components within the single, broadband Stokes source. The narrow band then scatters from the excited coherences, producing CARS and CSRS simultaneously. We discuss phase matching for this new technique and its inherent advantages relative to pure rotational CARS as normally implemented.

  6. Evaluation of the polarization properties of a Philips-type prism for the construction of imaging polarimeters

    NASA Astrophysics Data System (ADS)

    Fernandez-Borda, R.; Waluschka, E.; Pellicori, S.; Martins, J. V.; Ramos-Izquierdo, L.; Cieslak, J. D.; Thompson, P.

    2009-08-01

    The design and construction of wide FOV imaging polarimeters for use in atmospheric remote sensing requires significant attention to the prevention of artificial polarization induced by the optical elements. Surface, coatings, and angles of incidence throughout the system must be carefully designed in order to minimize these artifacts because the remaining instrumental bias polarization is the main factor which drives the final polarimetric accuracy of the system. In this work, we present a detailed evaluation and analysis to explore the possibility of retrieving the initial polarization state of the light traveling through a generic system that has inherent instrumental polarization. Our case is a wide FOV lens and a splitter device. In particular, we chose as splitter device a Philips-type prism, because it is able to divide the signal in 3 independent channels that could be simultaneously analyze to retrieve the three first elements of the Stoke vector (in atmospheric applications the elliptical polarization can be neglected [1]). The Philips-type configuration is a versatile, compact and robust prism device that is typically used in three color camera systems. It has been used in some commercial polarimetric cameras which do not claim high accuracy polarization measurements [2]. With this work, we address the accuracy of our polarization inversion and measurements made with the Philips-type beam divider.

  7. The MESA polarimetry chain and the status of its double scattering polarimeter

    NASA Astrophysics Data System (ADS)

    Aulenbacher, K.; Bartolomé, P. Aguar; Molitor, M.; Tioukine, V.

    2013-11-01

    We plan to have two independent polarimetry systems at MESA based on totally different physical processes. A first one tries to minimize the systematic uncertainties in double polarized Mo/ller scattering, which is to be achieved by stored hydrogen atoms in an atomic trap (Hydro-Mo/ller-Polarimeter). The other one relies on the equality of polarizing and analyzing power which allows to measure the effective analyzing power of a polarimeter with very high accuracy. Since the status of Hydro-Mo/ller is presented in a separate paper we concentrate on the double scattering polarimeter in this article.

  8. Characterizing and Modeling the Noise and Complex Impedance of Feedhorn-Coupled TES Polarimeters

    SciTech Connect

    Appel, J. W.; Beall, J. A.; Essinger-Hileman, T.; Parker, L. P.; Staggs, S. T.; Visnjic, C.; Zhao, Y.; Austermann, J. E.; Halverson, N. W.; Henning, J. W.; Simon, S. M.; Becker, D.; Britton, J.; Cho, H. M.; Hilton, G. C.; Irwin, K. D.; Niemack, M. D.; Yoon, K. W.; Benson, B. A.; Bleem, L. E.

    2009-12-16

    We present results from modeling the electrothermal performance of feedhorn-coupled transition edge sensor (TES) polarimeters under development for use in cosmic microwave background (CMB) polarization experiments. Each polarimeter couples radiation from a corrugated feedhorn through a planar orthomode transducer, which transmits power from orthogonal polarization modes to two TES bolometers. We model our TES with two- and three-block thermal architectures. We fit the complex impedance data at multiple points in the TES transition. From the fits, we predict the noise spectra. We present comparisons of these predictions to the data for two TESes on a prototype polarimeter.

  9. The MESA polarimetry chain and the status of its double scattering polarimeter

    SciTech Connect

    Aulenbacher, K.; Bartolomé, P. Aguar; Molitor, M.; Tioukine, V.

    2013-11-07

    We plan to have two independent polarimetry systems at MESA based on totally different physical processes. A first one tries to minimize the systematic uncertainties in double polarized Mo/ller scattering, which is to be achieved by stored hydrogen atoms in an atomic trap (Hydro-Mo/ller-Polarimeter). The other one relies on the equality of polarizing and analyzing power which allows to measure the effective analyzing power of a polarimeter with very high accuracy. Since the status of Hydro-Mo/ller is presented in a separate paper we concentrate on the double scattering polarimeter in this article.

  10. Accuracy of Stokes integration for geoid computation

    NASA Astrophysics Data System (ADS)

    Ismail, Zahra; Jamet, Olivier; Altamimi, Zuheir

    2014-05-01

    Geoid determination by remove-compute-restore (RCR) technique involves the application of Stokes's integral on reduced gravity anomalies. Reduced gravity anomalies are obtained through interpolation after removing low degree gravity signal from space spherical harmonic model and high frequency from topographical effects and cover a spectre ranging from degree 150-200. Stokes's integral is truncated to a limited region around the computation point producing an error that will be reducing by a modification of Stokes's kernel. We study Stokes integral accuracy on synthetic signal of various frequency ranges, produced with EGM2008 spherical harmonic coefficients up to degree 2000. We analyse the integration error according to the frequency range of signal, the resolution of gravity anomaly grid and the radius of Stokes integration. The study shows that the behaviour of the relative errors is frequency independent. The standard Stokes kernel is though insufficient to produce 1cm geoid accuracy without a removal of the major part of the gravity signal up to degree 600. The Integration over an area of radius greater than 3 degree does not improve accuracy improvement. The results are compared to a similar experiment using the modified Stokes kernel formula (Ellmann2004, Sjöberg2003). References: Ellmann, A. (2004) The geoid for the Baltic countries determined by least-squares modification of Stokes formula. Sjöberg, LE (2003). A general model of modifying Stokes formula and its least-squares solution Journal of Geodesy, 77. 459-464.

  11. Collinear and noncollinear emission of anti-stokes and second order stokes Raman radiation

    NASA Astrophysics Data System (ADS)

    Aussenegg, F. R.; Lippitsch, M. E.; Brandmüller, J.; Nitsch, W.

    1981-04-01

    Generating higher order stimulated Raman scattering in benzene, apart from phase-matched anti-Stokes radiation a collinear anti-Stokes emission is observed, which is explained by parametric four-photon processes under mismatch condition.

  12. Recent Advances in the Exploration of the Small-Scale Structure of the Quiet Solar Atmosphere: Vortex Flows, the Horizontal Magnetic Field, and the Stokes- V Line-Ratio Method

    NASA Astrophysics Data System (ADS)

    Steiner, O.; Rezaei, R.

    2012-05-01

    We review (i) observations and numerical simulations of vortical flows in the solar atmosphere and (ii) measurements of the horizontal magnetic field in quiet Sun regions. First, we discuss various manifestations of vortical flows and emphasize the role of magnetic fields in mediating swirling motion created near the solar surface to the higher layers of the photosphere and to the chromosphere. We reexamine existing simulation runs of solar surface magnetoconvection with regard to vortical flows and compare to previously obtained results. Second, we reviews contradictory results and problems associated with measuring the angular distribution of the magnetic field in quiet Sun regions. Furthermore, we review the Stokes-V-amplitude ratio method for the lines Fe i λλ 630.15 and 630.25 nm. We come to the conclusion that the recently discovered two distinct populations in scatter plots of this ratio must not bee interpreted in terms of “uncollapsed'' and “collapsed'' fields but stem from weak granular magnetic fields and weak canopy fields located at the boundaries between granules and the intergranular space. Based on new simulation runs, we reaffirm earlier findings of a predominance of the horizontal field components over the vertical one, particularly in the upper photosphere and at the base of the chromosphere.

  13. A Single-Probe-Beam, Dual-Frequency Plasma Polarimeter

    NASA Astrophysics Data System (ADS)

    Munro, Blair; Hicks, Nathaniel

    2016-10-01

    A plasma polarimeter instrument is conceived that comprises a single microwave probe beam alternating between two discrete frequencies. The method is similar to a double-heterodyne approach proposed earlier, but reduces system complexity and cost by avoiding a frequency-swept source. The instrument uses a single detector per beamline. Initial synthetic diagnostic testing of the instrument design is presented, and the prospects for further cost and space saving by way of additive manufacturing of instrument quasi-optical components are considered. A test bench setup for initial testing of the dual-frequency source and optical path is described, as is the plan for magnetized plasma measurements in a new plasma laboratory facility at the University of Alaska Anchorage. Supported by UAA Elizabeth Tower Endowment and Complex Systems Group.

  14. Polarimeter for Low Energy X-ray Astrophysical Sources (PLEXAS)

    NASA Technical Reports Server (NTRS)

    Murray, Stephen S.; Pierce, David L. (Technical Monitor)

    2002-01-01

    The Polarimeter for Low Energy X-ray Astrophysical Sources (PLEXAS) is an astrophysics mission concept for measuring the polarization of X-ray sources at low energies below the C-K band (less than 277 eV). PLEXAS uses the concept of variations in the reflectivity of a multilayered X-ray telescope as a function of the orientation of an X-rays polarization vector with respect to the reflecting surface of the optic. By selecting an appropriate multilayer, and rotating the X-ray telescope while pointing to a source, there will be a modulation in the source intensity, as measured at the focus of the telescope, which is proportional to the degree of polarization in the source.

  15. Polarimeter measures sea state characteristics using emitted infrared radiation

    NASA Technical Reports Server (NTRS)

    Egan, W. G.; Hilgeman, T.

    1977-01-01

    An infrared polarimeter, capable of operating between 1 and 12 micrometers wavelength has been used to measure the polarization of emitted radiation from the sea. The observed polarization at 10.6 micrometers from a smooth sea was found to be positive, indicating the dominance of reflected infrared sky radiation over the emitted. With the appearance of waves, the percent polarization increased, as expected, for a zenith angle well above the Brewster angle for water. This is qualitatively in accordance with a model presented to explain the behavior. Initial analyses indicate that the polarized components of the sea's emitted and reflected radiation are affected by type and direction of waves, angle of viewing, and foam. The effects of variations in these parameters require further delineation. The infrared polarimetric technique appears to be a novel new passive method for remote monitoring of waves.

  16. Radar cross calibration investigation TAMU radar polarimeter calibration measurements

    NASA Technical Reports Server (NTRS)

    Blanchard, A. J.; Newton, R. W.; Bong, S.; Kronke, C.; Warren, G. L.; Carey, D.

    1982-01-01

    A short pulse, 20 MHz bandwidth, three frequency radar polarimeter system (RPS) operates at center frequencies of 10.003 GHz, 4.75 GHz, and 1.6 GHz and utilizes dual polarized transmit and receive antennas for each frequency. The basic lay-out of the RPS is different from other truck mounted systems in that it uses a pulse compression IF section common to all three RF heads. Separate transmit and receive antennas are used to improve the cross-polarization isolation at each particular frequency. The receive is a digitally controlled gain modulated subsystem and is interfaced directly with a microprocesser computer for control and data manipulation. Antenna focusing distance, focusing each antenna pair, rf head stability, and polarization characteristics of RPS antennas are discussed. Platform and data acquisition procedures are described.

  17. Micro-polarimeter for high performance liquid chromatography

    DOEpatents

    Yeung, Edward E.; Steenhoek, Larry E.; Woodruff, Steven D.; Kuo, Jeng-Chung

    1985-01-01

    A micro-polarimeter interfaced with a system for high performance liquid chromatography, for quantitatively analyzing micro and trace amounts of optically active organic molecules, particularly carbohydrates. A flow cell with a narrow bore is connected to a high performance liquid chromatography system. Thin, low birefringence cell windows cover opposite ends of the bore. A focused and polarized laser beam is directed along the longitudinal axis of the bore as an eluent containing the organic molecules is pumped through the cell. The beam is modulated by air gap Faraday rotators for phase sensitive detection to enhance the signal to noise ratio. An analyzer records the beams's direction of polarization after it passes through the cell. Calibration of the liquid chromatography system allows determination of the quantity of organic molecules present from a determination of the degree to which the polarized beam is rotated when it passes through the eluent.

  18. Imaging X-Ray Polarimeter for Solar Flares (IXPS)

    NASA Technical Reports Server (NTRS)

    Hosack, Michael; Black, J. Kevin; Deines-Jones, Philip; Dennis, Brian R.; Hill, Joanne E.; Jahoda, Keith; Shih, Albert Y.; Urba, Christian E.; Emslie, A. Gordon

    2011-01-01

    We describe the design of a balloon-borne Imaging X-ray Polarimeter for Solar flares (IX PS). This novel instrument, a Time Projection Chamber (TPC) for photoelectric polarimetry, will be capable of measuring polarization at the few percent level in the 20-50 keV energy range during an M- or X class flare, and will provide imaging information at the approx.10 arcsec level. The primary objective of such observations is to determine the directivity of nonthermal high-energy electrons producing solar hard X-rays, and hence to learn about the particle acceleration and energy release processes in solar flares. Secondary objectives include the separation of the thermal and nonthermal components of the flare X-ray emissions and the separation of photospheric albedo fluxes from direct emissions.

  19. New imaging polarimeter for the Mont-Megantic Observatory

    NASA Astrophysics Data System (ADS)

    Bastien, Pierre; Ross, Vincent; Hernandez, Olivier

    2003-02-01

    An imaging polarimeter for the visible has been built for the mont Mégantic Observatory. It uses a new design with a Foster prism which allows to obtain the two orthogonal beams of polarized light onto the detector at the same time, thus alleviating calibration problems associated with variations in the sky transparency during the observations. The field of view is 2.4 arc minutes at the f/15 focus of the telescope. A rotating achromatic half-wave plate is used to get all the linear polarization components and eliminate systematic calibration effects. Circularly polarized images can also be obtained by substituting a quarter-wave plate for the rotating half-wave plate. A user-friendly software for carrying out the data reduction has been developed.

  20. Upgrades to the C-Mod FIR Polarimeter

    NASA Astrophysics Data System (ADS)

    Abraham, Sameer; Irby, Jim; Watterson, Reich; Vieira, Rui; Leccacorvi, Rick; Parkin, William; Murray, Rick; Marmar, Earl

    2016-10-01

    The 3-Chord FIR Polarimeter presently deployed on C-Mod is capable of responding to both fast changes in the plasma equilibrium and high frequency fluctuations. Two FIR lasers locked together with a slight frequency offset provide a signal IF at 4 MHz, which allows for the fast response of the system. Recently implemented upgrades including relocation of the laser table from the C-Mod experimental cell to a more shielded location, the design and installation of a humidity controlled beam-line to convey the FIR beams across the cell, and improved collimation optics will be discussed. Results from initial testing of the system during C-Mod operation, as well as fluctuation data from the most recent and previous campaigns will be presented and compared. Supported by USDoE Award DE-FC02-99ER54512.

  1. Precision Spectroscopy of Hydrogen with a Lamb-Shift Polarimeter

    SciTech Connect

    Engels, R.; Schug, G.; Stroeher, H.; Vasilyev, A.; Grigoryev, K.; Mikirtytchyants, M.; Schieck, H. Paetz gen.; Westig, M.

    2009-08-04

    A spinfilter, the most important component of a Lamb-shift polarimeter, is used to produce a beam of metastable hydrogen (deuterium) atoms in one hyperfine state (HFS)(alpha1, alpha2 and together with the Sona transition beta3). As function of a magnetic field separated transitions between the 2s{sub 1/2} metastable Zeeman states seem to be observable as well as single transitions into the short-lived 2P{sub 1/2} and 2P{sub 3/2} states. The Breit-Rabi diagrams for these states and, therefore, the g factors can be measured with good precision. Furthermore, the hyperfine splittings and the Lamb shift can be observed as well. Application of this method to anti-hydrogen atoms is suggested.

  2. The Hertz/VPM Polarimeter: Design and First Light Observations

    NASA Technical Reports Server (NTRS)

    Krejny, Megan; Chuss, David; d'Aubigny, Christian Drouet; Golish, Dathon; Houde, Martin; Hui, Howard; Kulesa, Craig; Loewenstein, Robert F.; Moseley, Harvey; Novak, Giles; Voellmer, George; Walker, Chris; Wollack, Ed

    2008-01-01

    We present first results of Hertz/VPM, the first submillimeter polarimeter employing the dual Variable-delay Polarization Modulator (dual-VPM). This device differs from previously used polarization modulators in that it, operates in translation rather than mechanical rotation. We discuss the basic theory behind this device, and its potential advantages over the commonly used half wave plate (HFVP). The dual-VPM was tested both at the Submillimeter Telescope Observatory (SMTO) and in the lab. In each case we present a detailed description of the setup. We discovered nonideal behavior in the system. This is at least in part due to properties of the VPM wire grids (diameter, spacing) employed in our experiment. Despite this, we found that the dual-VPM system is robust, operating with high efficiency and low instrumental polarization. This device is well suited for air and space-borne applications.

  3. A low-cost polarimeter for an undergraduate laboratory to study the polarization pattern of skylight

    NASA Astrophysics Data System (ADS)

    Abayaratne, Chula P.; Bandara, Vibodha

    2017-03-01

    A simple, low-cost, fully automated polarimeter, which demonstrates fundamental properties of skylight scattering and polarization for undergraduate physics students, is described. The polarimeter includes a microprocessor-based control unit, a Sun tracker, an elevation-azimuth mount with two degrees of freedom, and a polarization sensor unit equipped with a light-dependent resistor for measuring light intensity. Results obtained in the principal plane of the Sun using the polarimeter on a relatively clear day, together with the theoretically expected results for a molecular atmosphere, are presented. A root-mean-square error comparison indicates fairly good agreement between theory and experiment. Construction and experimentation with the polarimeter will provide students with insight into important physical concepts involved in skylight scattering and polarization as well as improve their instrumentation capabilities.

  4. A photon calorimeter using lead tungstate crystals for the CEBAF HAll A Compton polarimeter

    SciTech Connect

    D. Neyret; T. Pussieux; T. Auger; M. Baylac; E. Burtin; C. Cavata; R. Chipaux; S. Escoffier; N. Falletto; J. Jardillier; S. Kerhoas; D. Lhuillier; F. Marie; C. Veyssiere; J. Ahrens; R. Beck; M. Lang

    2000-05-01

    A new Compton polarimeter is built on the CEBAF Hall A electron beam line. Performances of 10% resolution and 1% calibration are required for the photon calorimeter of this polarimeter. This calorimeter is built with lead tungstate scintillators coming from the CMS electromagnetic calorimeter R&D. Beam tests of this detector have been made using the tagged photon beam line at MAMI, Mainz, and a resolution of 1.76%+2.75%/v+0.41%/E has been measured.

  5. The test of the layout of polarimeter "UFP" on the telescope AZT-2

    NASA Astrophysics Data System (ADS)

    Levchenko, T. A.; Nevodovskyi, P. V.; Vidmachenko, A. P.; Morozhenko, O. V.; Saryboha, H. V.; Zbrutsky, O. V.; Ivakhiv, O. V.

    2016-05-01

    Main Astronomical Observatory of NAS of Ukraine in cooperation with the National Technical University of Ukraine "KPI" and National University "Lviv Polytechnic" for a long time working on the design of an optical polarimeter to study of the stratospheric layer of the Earth using of orbital satellite. During this time, was accumulated a large experience of such work, and was established a layout of compact ultraviolet polarimeter (UFP) on board of satellite

  6. Vibrational energy dynamics of water studied with ultrafast Stokes and anti-Stokes Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Wang, Zhaohui; Pang, Yoonsoo; Dlott, Dana D.

    2004-10-01

    The transient Stokes Raman spectroscopy method is introduced to study the dynamics of OH-stretching vibrations in water excited by ultrashort infrared pulses. The combination of Stokes and anti-Stokes Raman probing allows the the absorption and emission contributions to be measured separately. Experiments with 3400 cm -1 pumping of OH-stretching of HOD solute in D 2O solvent are reported. The Stokes Raman method is used to study the delay between the excited-state decay and the ground-state recovery, the vibrational Stokes shift, and the generation of weakened hydrogen bonding due to heat released by vibrational relaxation.

  7. A 3D CZT hard x-ray polarimeter for a balloon-borne payload

    NASA Astrophysics Data System (ADS)

    Caroli, E.; Alvarez, J. M.; Auricchio, N.; Budtz-Jørgensen, C.; Curado da Silva, R. M.; Del Sordo, S.; Ferrando, P.; Laurent, P.; Limousin, O.; Galvèz, J. L.; Gloster, C. P.; Hernanz, M.; Isern, J.; Kuvvetli, I.; Maia, J. M.; Meuris, A.; Stephen, J. B.; Zappettini, A.

    2012-09-01

    Today it is widely recognised that a measurement of the polarization status of cosmic sources high energy emission is a key observational parameter to understand the active production mechanism and its geometry. Therefore new instrumentation operating in the hard X/soft γ rays energy range should be optimized also for this type of measurement. In this framework, we present the concept of a small high-performance spectrometer designed for polarimetry between 100 and 1000 keV suitable as a stratospheric balloon-borne payload dedicated to perform an accurate and reliable measurement of the polarization status of the Crab pulsar, i.e. the polarization level and direction. The detector with 3D spatial resolution is based on a CZT spectrometer in a highly segmented configuration designed to operate as a high performance scattering polarimeter. We discuss different configurations based on recent development results and possible improvements currently under study. Furthermore we describe a possible baseline design of the payload, which can be also seen as a pathfinder for a high performance focal plane detector in new hard X and soft gamma ray focussing telescopes and/or advanced Compton instruments. Finally we present preliminary data from Montecarlo undergoing studies to determine the best trade-off between polarimetric performance and detector design complexity.

  8. Reconstruction of the Density Profile for the EAST Tokamak Based on Polarimeter/Interferometer and Microwave Reflectometer Systems

    NASA Astrophysics Data System (ADS)

    Zhu, Xiang; Zeng, Long; Liu, Haiqing; Jie, Yinxian; Zhang, Shoubiao; Hu, Jiansheng; Gao, Xiang

    2015-09-01

    A plasma density profile reconstruction procedure based on the Park matrix method has been developed for both circular and elongated plasma configuration on the Experimental Advanced Superconducting Tokamak (EAST). This method incorporates the line integrated electron density measured by the HCN interferometer and polarimeter/interferometer (POINT) system, the equilibrium fit (EFIT) based on magnetic measurements and the edge electron density profile provided by the microwave reflectometer. It is shown that when the magnetic flux surfaces are slightly corrected, the fitting error is less than 5% in comparison with the measurement data. supported by the National Magnetic Confinement Fusion Science Program of China (Nos. 2013GB106003, 2014GB106004 and 2014GB106002) and National Natural Science Foundation of China (Nos. 11475221 and 11105184)

  9. Stokes polarimetry imaging of dog prostate tissue

    NASA Astrophysics Data System (ADS)

    Kim, Jihoon; Johnston, William K., III; Walsh, Joseph T., Jr.

    2010-02-01

    Prostate cancer is the second leading cause of death in the United States in 2009. Radical prostatectomy (complete removal of the prostate) is the most common treatment for prostate cancer, however, differentiating prostate tissue from adjacent bladder, nerves, and muscle is difficult. Improved visualization could improve oncologic outcomes and decrease damage to adjacent nerves and muscle important for preservation of potency and continence. A novel Stokes polarimetry imaging (SPI) system was developed and evaluated using a dog prostate specimen in order to examine the feasibility of the system to differentiate prostate from bladder. The degree of linear polarization (DOLP) image maps from linearly polarized light illumination at different visible wavelengths (475, 510, and 650 nm) were constructed. The SPI system used the polarization property of the prostate tissue. The DOLP images allowed advanced differentiation by distinguishing glandular tissue of prostate from the muscular-stromal tissue in the bladder. The DOLP image at 650 nm effectively differentiated prostate and bladder by strong DOLP in bladder. SPI system has the potential to improve surgical outcomes in open or robotic-assisted laparoscopic removal of the prostate. Further in vivo testing is warranted.

  10. PEPSI: The high-resolution échelle spectrograph and polarimeter for the Large Binocular Telescope

    NASA Astrophysics Data System (ADS)

    Strassmeier, K. G.; Ilyin, I.; Järvinen, A.; Weber, M.; Woche, M.; Barnes, S. I.; Bauer, S.-M.; Beckert, E.; Bittner, W.; Bredthauer, R.; Carroll, T. A.; Denker, C.; Dionies, F.; DiVarano, I.; Döscher, D.; Fechner, T.; Feuerstein, D.; Granzer, T.; Hahn, T.; Harnisch, G.; Hofmann, A.; Lesser, M.; Paschke, J.; Pankratow, S.; Plank, V.; Plüschke, D.; Popow, E.; Sablowski, D.

    2015-05-01

    PEPSI is the bench-mounted, two-arm, fibre-fed and stabilized Potsdam Echelle Polarimetric and Spectroscopic Instrument for the 2×8.4 m Large Binocular Telescope (LBT). Three spectral resolutions of either 43 000, 120 000 or 270 000 can cover the entire optical/red wavelength range from 383 to 907 nm in three exposures. Two 10.3k×10.3k CCDs with 9-μm pixels and peak quantum efficiencies of 94-96 % record a total of 92 échelle orders. We introduce a new variant of a wave-guide image slicer with 3, 5, and 7 slices and peak efficiencies between 92-96 %. A total of six cross dispersers cover the six wavelength settings of the spectrograph, two of them always simultaneously. These are made of a VPH-grating sandwiched by two prisms. The peak efficiency of the system, including the telescope, is 15 % at 650 nm, and still 11 % and 10 % at 390 nm and 900 nm, respectively. In combination with the 110 m2 light-collecting capability of the LBT, we expect a limiting magnitude of ≈ 20th mag in V in the low-resolution mode. The R = 120 000 mode can also be used with two, dual-beam Stokes IQUV polarimeters. The 270 000-mode is made possible with the 7-slice image slicer and a 100-μm fibre through a projected sky aperture of 0.74 arcsec, comparable to the median seeing of the LBT site. The 43 000-mode with 12-pixel sampling per resolution element is our bad seeing or faint-object mode. Any of the three resolution modes can either be used with sky fibers for simultaneous sky exposures or with light from a stabilized Fabry-Pérot étalon for ultra-precise radial velocities. CCD-image processing is performed with the dedicated data-reduction and analysis package PEPSI-S4S. Its full error propagation through all image-processing steps allows an adaptive selection of parameters by using statistical inferences and robust estimators. A solar feed makes use of PEPSI during day time and a 500-m feed from the 1.8 m VATT can be used when the LBT is busy otherwise. In this paper, we

  11. High-resolution, high-sensitivity, ground-based solar spectropolarimetry with a new fast imaging polarimeter. I. Prototype characterization

    NASA Astrophysics Data System (ADS)

    Iglesias, F. A.; Feller, A.; Nagaraju, K.; Solanki, S. K.

    2016-05-01

    Context. Remote sensing of weak and small-scale solar magnetic fields is of utmost relevance when attempting to respond to a number of important open questions in solar physics. This requires the acquisition of spectropolarimetric data with high spatial resolution (~10-1 arcsec) and low noise (10-3 to 10-5 of the continuum intensity). The main limitations to obtain these measurements from the ground, are the degradation of the image resolution produced by atmospheric seeing and the seeing-induced crosstalk (SIC). Aims: We introduce the prototype of the Fast Solar Polarimeter (FSP), a new ground-based, high-cadence polarimeter that tackles the above-mentioned limitations by producing data that are optimally suited for the application of post-facto image restoration, and by operating at a modulation frequency of 100 Hz to reduce SIC. Methods: We describe the instrument in depth, including the fast pnCCD camera employed, the achromatic modulator package, the main calibration steps, the effects of the modulation frequency on the levels of seeing-induced spurious signals, and the effect of the camera properties on the image restoration quality. Results: The pnCCD camera reaches 400 fps while keeping a high duty cycle (98.6%) and very low noise (4.94 e- rms). The modulator is optimized to have high (>80%) total polarimetric efficiency in the visible spectral range. This allows FSP to acquire 100 photon-noise-limited, full-Stokes measurements per second. We found that the seeing induced signals that are present in narrow-band, non-modulated, quiet-sun measurements are (a) lower than the noise (7 × 10-5) after integrating 7.66 min, (b) lower than the noise (2.3 × 10-4) after integrating 1.16 min and (c) slightly above the noise (4 × 10-3) after restoring case (b) by means of a multi-object multi-frame blind deconvolution. In addition, we demonstrate that by using only narrow-band images (with low S/N of 13.9) of an active region, we can obtain one complete set of high

  12. Stokes flow in ellipsoidal geometry

    NASA Astrophysics Data System (ADS)

    Vafeas, Panayiotis; Dassios, George

    2006-09-01

    Particle-in-cell models for Stokes flow through a relatively homogeneous swarm of particles are of substantial practical interest, because they provide a relatively simple platform for the analytical or semianalytical solution of heat and mass transport problems. Despite the fact that many practical applications involve relatively small particles (inorganic, organic, biological) with axisymmetric shapes, the general consideration consists of rigid particles of arbitrary shape. The present work is concerned with some interesting aspects of the theoretical analysis of creeping flow in ellipsoidal, hence nonaxisymmetric domains. More specifically, the low Reynolds number flow of a swarm of ellipsoidal particles in an otherwise quiescent Newtonian fluid, that move with constant uniform velocity in an arbitrary direction and rotate with an arbitrary constant angular velocity, is analyzed with an ellipsoid-in-cell model. The solid internal ellipsoid represents a particle of the swarm. The external ellipsoid contains the ellipsoidal particle and the amount of fluid required to match the fluid volume fraction of the swarm. The nonslip flow condition on the surface of the solid ellipsoid is supplemented by the boundary conditions on the external ellipsoidal surface which are similar to those of the sphere-in-cell model of Happel (self-sufficient in mechanical energy). This model requires zero normal velocity component and shear stress. The boundary value problem is solved with the aim of the potential representation theory. In particular, the Papkovich-Neuber complete differential representation of Stokes flow, valid for nonaxisymmetric geometries, is considered here, which provides the velocity and total pressure fields in terms of harmonic ellipsoidal eigenfunctions. The flexibility of the particular representation is demonstrated by imposing some conditions, which made the calculations possible. It turns out that the velocity of first degree, which represents the leading

  13. Stokes scattering matrix for human skin.

    PubMed

    Bhandari, Anak; Stamnes, Snorre; Hamre, Børge; Frette, Oyvind; Stamnes, Knut; Stamnes, Jakob J

    2012-11-01

    We use a layered model of normal human skin based on size distributions of polydisperse spherical particles and their complex refractive indices to compute the Stokes scattering matrix at wavelengths in the visible spectral band. The elements of the Stokes scattering matrix are required in a polarized radiative transfer code for a coupled air-tissue system to compute the polarized reflectance and examine how it is dependent on the vertical structure of the inherent optical properties of skin, including the phase matrix. Thus, the elements of the Stokes scattering matrix can be useful for investigating polarization-dependent light propagation in turbid optical media, such as human skin tissue.

  14. Stochastic 2-D Navier-Stokes Equation

    SciTech Connect

    Menaldi, J.L. Sritharan, S.S.

    2002-10-01

    In this paper we prove the existence and uniqueness of strong solutions for the stochastic Navier-Stokes equation in bounded and unbounded domains. These solutions are stochastic analogs of the classical Lions-Prodi solutions to the deterministic Navier-Stokes equation. Local monotonicity of the nonlinearity is exploited to obtain the solutions in a given probability space and this significantly improves the earlier techniques for obtaining strong solutions, which depended on pathwise solutions to the Navier-Stokes martingale problem where the probability space is also obtained as a part of the solution.

  15. Navier-Stokes analysis of blunt trailing edge airfoils

    NASA Technical Reports Server (NTRS)

    Stanaway, Sharon; Mccroskey, W. J.; Kroo, Ilan

    1992-01-01

    The flow around blunt trailing edge airfoils was studied by solving the Reynolds-averaged Navier-Stokes equations. The solution procedure combines a grid around the airfoil with a second grid for the wake so that the time advancement over the domain is fully implicit. This is not only very efficient for the algorithm but also allows implicit solutions of a one equation turbulence model appropriate for both boundary layers and wakes. An algebraic and two one-equation turbulence models are tested for a blunt RAE 2822 airfoil section and detailed comparisons with experimental data are presented in the trailing edge region.

  16. On entanglement of light and Stokes parameters

    NASA Astrophysics Data System (ADS)

    Żukowski, Marek; Laskowski, Wiesław; Wieśniak, Marcin

    2016-08-01

    We present a new approach to Stokes parameters, which enables one to see better non-classical properties of bright quantum light, and of undefined overall photon numbers. The crucial difference is as follows. The standard quantum optical Stokes parameters are averages of differences of intensities of light registered at the two exits of polarization analyzers, and one gets their normalized version by dividing them by the average total intensity. The new ones are averages of the registered normalized Stokes parameters, for the duration of the experiment. That is, we redefine each Stokes observable as the difference of photon number operators at the two exits of a polarizing beam splitter multiplied by the inverse of their sum. The vacuum eigenvalue of the operator is defined a zero. We show that with such an approach one can obtain more sensitive entanglement indicators based on polarization measurements.

  17. Chromospheric Lyman-Alpha SpectroPolarimeter (CLASP)

    NASA Technical Reports Server (NTRS)

    Kano, Ryohei; Bando, Takamasa; Narukage, Noriyuki; Ishikawa, Ryoko; Kubo, Masahito; Katsukawa, Yukio; Ishikawa, Shin-­nosuke; Hara, Hirohisa; Suematsu, Yoshinori; Giono, Gabriel; Shimizu, Toshifumi; Sakao, Taro; Ichimoto, Kiyoshi; Goto, Motoshi; Winebarger, amy; Kobayashi, Ken; Trujullo Bueno, Javier; Auchere, Frederic

    2015-01-01

    Chromosphere, the transition layer of the sun is a region to switch to the magnetic pressure dominated from plasma pressure dominated, simultaneous observation of the detailed magnetic field measurement and plasma of dynamic phenomenon here is what is the frontier of the next solar physics. As This is a challenge that has just mentioned, even the next solar observation satellite plan SOLAR-C, in the experiments we had used a NASA sounding rocket for the first time in the SOLAR-C plan, will address the chromosphere-transition layer magnetic field measurement there. It is, is a Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) plan, the linear polarization of Lyman ?? emission lines chromosphere-transition layer shoots (121.6nm) were detected in 0.1 percent of high accuracy, a new technique called Hanre effect I get the magnetic field information of chromosphere-transition layer. In Japan, the US and Europe joint observation in November 2012 as a rocket experiment is adopted to NASA this plan that full-scale start-up, start from assembly work is 2014 spring flight observation device, currently, it is where the alignment of the optical elements have been implemented. After this, it is planned to continue with the performance evaluation towards the observation implementation of summer 2015. In addition to once again explain the contents of the plan In this presentation, we report an overview of the entire development and preparation current status.

  18. Upgrade Plans for the C-Mod FIR Polarimeter

    NASA Astrophysics Data System (ADS)

    Watterson, R.; Garnier, D.; Irby, J.; Brower, D. L.; Xu, P.; Bergerson, W. F.; Ding, W. X.; Guttenfelder, W.; Marmar, E. S.

    2014-10-01

    The 3-chord FIR polarimeter presently deployed on C-Mod is capable of responding to both fast changes in the plasma equilibrium and high frequency fluctuations. It operates under ITER-like plasma conditions and magnetic fields, and uses an optical layout similar to that proposed for ITER. The details of this system and some results from the C-Mod 2012 campaign will be presented, along with the design of the upgrade that is now being implemented. The new system will provide horizontal chords near the mid-plane and low loss etalon windows to improve both the signal level and our ability to study magnetic fluctuations. The laser table has been relocated from the C-Mod cell to a shielded and climate controlled location, and improvements have been made to its acoustic isolation. New collimation optics, and a beam-line needed to convey the FIR beams into the tokamak port have been designed. Improvements to the detector electronics will also be discussed, as will initial testing of the laser system and reference detectors during C-Mod operation. Supported by USDoE Award DE-FC02-99ER54512.

  19. Super-resolution for imagery from integrated microgrid polarimeters.

    PubMed

    Hardie, Russell C; LeMaster, Daniel A; Ratliff, Bradley M

    2011-07-04

    Imagery from microgrid polarimeters is obtained by using a mosaic of pixel-wise micropolarizers on a focal plane array (FPA). Each distinct polarization image is obtained by subsampling the full FPA image. Thus, the effective pixel pitch for each polarization channel is increased and the sampling frequency is decreased. As a result, aliasing artifacts from such undersampling can corrupt the true polarization content of the scene. Here we present the first multi-channel multi-frame super-resolution (SR) algorithms designed specifically for the problem of image restoration in microgrid polarization imagers. These SR algorithms can be used to address aliasing and other degradations, without sacrificing field of view or compromising optical resolution with an anti-aliasing filter. The new SR methods are designed to exploit correlation between the polarimetric channels. One of the new SR algorithms uses a form of regularized least squares and has an iterative solution. The other is based on the faster adaptive Wiener filter SR method. We demonstrate that the new multi-channel SR algorithms are capable of providing significant enhancement of polarimetric imagery and that they outperform their independent channel counterparts.

  20. The Calibration of the PEPPo Polarimeter for Electrons and Positrons

    SciTech Connect

    Adeyemi, Adeleke Hakeem; Voutier, Eric J-.M.

    2013-06-01

    The PEPPo (Polarized Electrons for Polarized Positrons) experiment at Jefferson Laboratory investigated the polarization transfer from longitudinally polarized electrons to longitudinally polarized positrons, with the aim of developing this technology for a low energy (~MeV) polarized positron source. Polarization of the positrons was measured by means of a Compton transmission polarimeter where incoming positrons transfer their polarization into circularly polarized photons that were subsequently analyzed by a thick polarized iron target. The measurement of the transmitted photon flux with respect to the orientation of the target polarization (+-) or the helicity (+-) of the incoming leptons provided the measurement of their polarization. Similar measurements with a known electron beam were also performed for calibration purposes. This presentation will describe the apparatus and calibrations performed at the injector at the Jefferson Laboratory to measure positron polarization in the momentum range 3.2-6.2 MeV/c, specifically to quantify the positron analyzing power from electron experimental data measured over a comparable momentum range.

  1. Hard x-ray imaging polarimeter for PolariS

    NASA Astrophysics Data System (ADS)

    Hayashida, Kiyoshi; Kim, Juyong; Sadamoto, Masaaki; Yoshinaga, Keigo; Gunji, Shuichi; Mihara, Tatehiro; Kishimoto, Yuji; Kubo, Hidetoshi; Mizuno, Tsunefumi; Takahashi, Hiromitsu; Dotani, Tadayasu; Yonetoku, Daisuke; Nakamori, Takeshi; Yoneyama, Tomokage; Ikeyama, Yuki; Kamitsukasa, Fumiyoshi

    2016-07-01

    Hard X-ray imaging polarimeters are developed for the X-ray γ-ray polaeimtery satellite PolariS. The imaging polarimter is scattering type, in which anisotropy in the direction of Compton scattering is employed to measure the hard X-ray (10-80 keV) polarization, and is installed on the focal planes of hard X-ray telescopes. We have updated the design of the model so as to cover larger solid angles of scattering direction. We also examine the event selection algorithm to optimize the detection efficiency of recoiled electrons in plastic scintillators. We succeed in improving the efficiency by factor of about 3-4 from the previous algorithm and criteria for 18-30 keV incidence. For 23 keV X-ray incidence, the recoiled electron energy is about 1 keV. We measured the efficiency to detect recoiled electrons in this case, and found about half of the theoretical limit. The improvement in this efficiency directly leads to that in the detection efficiency. In other words, however, there is still a room for improvement. We examine various process in the detector, and estimate the major loss is primarily that of scintillation light in a plastic scintillator pillar with a very small cross section (2.68mm squared) and a long length (40mm). Nevertheless, the current model provides the MDP of 6% for 10mCrab sources, which are the targets of PolariS.

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

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

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

  3. Lifetime Estimation of a Time Projection Chamber X-ray Polarimeter

    NASA Technical Reports Server (NTRS)

    Hill, Joanne E.; Black, J. Kevin; Brieda, Lubos; Dickens, Patsy L.; deGarcia, Kristina Montt; Hawk, Douglas L.; Hayato, Asami; Jahoda, Keith; Mohammed, Jelila

    2013-01-01

    The Gravity and Extreme Magnetism Small Explorer (GEMS) X-ray polarimeter Instrument (XPI) was designed to measure the polarization of 23 sources over the course of its 9 month mission. The XPI design consists of two telescopes each with a polarimeter assembly at the focus of a grazing incidence mirror. To make sensitive polarization measurements the GEMS Polarimeter Assembly (PA) employed a gas detection system based on a Time Projection Chamber (TPC) technique. Gas detectors are inherently at risk of degraded performance arising from contamination from outgassing of internal detector components or due to loss of gas. This paper describes the design and the materials used to build a prototype of the flight polarimeter with the required GEMS lifetime. We report the results from outgassing measurements of the polarimeter subassemblies and assemblies, enclosure seal tests, life tests, and performance tests that demonstrate that the GEMS lifetime is achievable. Finally we report performance measurements and the lifetime enhancement from the use of a getter.

  4. Airborne polarimeter intercomparison for the NASA Aerosol-Cloud-Ecosystem (ACE) mission

    NASA Astrophysics Data System (ADS)

    Knobelspiesse, K. D.; Redemann, J.

    2014-12-01

    The Aerosol-Cloud-Ecosystem (ACE) mission, recommended by the National Research Council's Decadal Survey, calls for a multi-angle, multi-spectral polarimeter devoted to observations of atmospheric aerosols and clouds. In preparation for ACE, NASA funds the deployment of airborne polarimeter prototypes, including the Airborne Multi-angle SpectroPolarimeter Imager (AirMSPI), the Passive Aerosol and Cloud Suite (PACS) and the Research Scanning Polarimeter (RSP). These instruments have been operated together on NASA's ER-2 high altitude aircraft as part of field campaigns such as the POlarimeter DEfinition EXperiment (PODEX) (California, early 2013) and Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS, California and Texas, summer 2013). Our role in these efforts has been to serve as an assessment team performing level 1 (calibrated radiance, polarization) and level 2 (retrieved geophysical parameter) instrument intercomparisons, and to promote unified and generalized calibration, uncertainty assessment and retrieval techniques. We will present our progress in this endeavor thus far and describe upcoming research in 2015.

  5. Run05 Proton Beam Polarization Measurements by pC-Polarimeter (ver. 1.1)

    SciTech Connect

    Nakagawa,I.; Alekseev, I.; Bazilevsky, A.; Bravar, A.; Bunce, G.; Dhawan, S.; Eyser, K.O.; Gill, R.; Haeberli, W.; Huang, H.; Makdisi, Y.; Nass, A.; Okada, H.; Stephenson, E.; Svirida, D.N.; Wise, T.; Wood, J.; Yip, K.; Zelenski, A.

    2008-07-01

    The polarization of the proton beams [1, 2] at the Relativistic Heavy Ion Collider (RHIC)[3] RHIC ring. The H-Jet polarimeter is located at the collision point allowing measurements of absolute normalization is provided by the hydrogen polarimeter, which measures over 1 {approx} 2 another measurement rather than measuring the absolute polarization. both beams. Two identical pC-polarimeters are equipped in the yellow and blue rings, where carbon ribbon target, providing fast feedback to beam operations and experiments. The days to obtain {approx} 5% statistical uncertainty (in Run05). Thus, the operation of the carbon is measured using both an atomic beam source hydrogen gas jet (H-Jet)[4, 5] and proton-carbon polarimeters was focused on better control of relative stability between one measurement to statistical accuracy within 20 to 30 seconds using an ultra-thin (typically 6 {approx} 8 {micro}g/cm{sup 2}) the rings are separated. The pC-polarimeter measures relative polarization to a few percent.

  6. A low-voltage retarding-field Mott polarimeter for photocathode characterization

    SciTech Connect

    McCarter, J. L.; Stutzman, M. L.; Trantham, K. W.; Anderson, T. G.; Cook, A. M.; Gay, T. J.

    2010-02-26

    Nuclear physics experiments at Thomas Jefferson National Accelerator Facility's CEBAF rely on high polarization electron beams. We describe a recently commissioned system for prequalifying and studying photocathodes for CEBAF with a load-locked, low-voltage polarized electron source coupled to a compact retarding-field Mott polarimeter. The polarimeter uses simplified electrode structures and operates from 5 to 30 kV. The effective Sherman function for this device has been calibrated by comparison with the CEBAF 5 MeV Mott polarimeter. For elastic scattering from a thick gold target at 20 keV, the effective Sherman function is 0.201(5). Its maximum efficiency at 20 keV, defined as the detected count rate divided by the incident particle current, is 5.4(2)×10-4, yielding a figure-of-merit, or analyzing power squared times efficiency, of 1.0(1)×10-5. The operating parameters of this new polarimeter design are compared to previously published data for other compact Mott polarimeters of the retarding-field type.

  7. A low-voltage retarding-field Mott polarimeter for photocathode characterization

    NASA Astrophysics Data System (ADS)

    McCarter, J. L.; Stutzman, M. L.; Trantham, K. W.; Anderson, T. G.; Cook, A. M.; Gay, T. J.

    2010-06-01

    Nuclear physics experiments at Thomas Jefferson National Accelerator Facility's CEBAF rely on high polarization electron beams. We describe a recently commissioned system for prequalifying and studying photocathodes for CEBAF with a load-locked, low-voltage polarized electron source coupled to a compact retarding-field Mott polarimeter. The polarimeter uses simplified electrode structures and operates from 5 to 30 kV. The effective Sherman function for this device has been calibrated by comparison with the CEBAF 5 MeV Mott polarimeter. For elastic scattering from a thick gold target at 20 keV, the effective Sherman function is 0.201(5). Its maximum efficiency at 20 keV, defined as the detected count rate divided by the incident particle current, is 5.4(2)×10 -4, yielding a figure-of-merit, or analyzing power squared times efficiency, of 1.0(1)×10 -5. The operating parameters of this new polarimeter design are compared to previously published data for other compact Mott polarimeters of the retarding-field type.

  8. Progress in Airborne Polarimeter Inter Comparison for the NASA Aerosols-Clouds-Ecosystems (ACE) Mission

    NASA Technical Reports Server (NTRS)

    Knobelspiesse, Kirk; Redemann, Jens

    2014-01-01

    The Aerosols-Clouds-Ecosystems (ACE) mission, recommended by the National Research Council's Decadal Survey, calls for a multi-angle, multi-spectral polarimeter devoted to observations of atmospheric aerosols and clouds. In preparation for ACE, NASA funds the deployment of airborne polarimeters, including the Airborne Multiangle SpectroPolarimeter Imager (AirMSPI), the Passive Aerosol and Cloud Suite (PACS) and the Research Scanning Polarimeter (RSP). These instruments have been operated together on NASA's ER-2 high altitude aircraft as part of field campaigns such as the POlarimeter DEfinition EXperiment (PODEX) (California, early 2013) and Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS, California and Texas, summer 2013). Our role in these efforts has been to serve as an assessment team performing level 1 (calibrated radiance, polarization) and level 2 (retrieved geophysical parameter) instrument intercomparisons, and to promote unified and generalized calibration, uncertainty assessment and retrieval techniques. We will present our progress in this endeavor thus far and describe upcoming research in 2015.

  9. Airborne Polarimeter Intercomparison for the NASA Aerosols-Clouds-Ecosystems (ACE) Mission

    NASA Technical Reports Server (NTRS)

    Knobelspiesse, Kirk; Redemann, Jens

    2014-01-01

    The Aerosols-Clouds-Ecosystems (ACE) mission, recommended by the National Research Council's Decadal Survey, calls for a multi-angle, multi-spectral polarimeter devoted to observations of atmospheric aerosols and clouds. In preparation for ACE, NASA funds the deployment of airborne polarimeters, including the Airborne Multi-angle SpectroPolarimeter Imager (AirMSPI), the Passive Aerosol and Cloud Suite (PACS) and the Research Scanning Polarimeter (RSP). These instruments have been operated together on NASA's ER-2 high altitude aircraft as part of field campaigns such as the POlarimeter DEfinition EXperiment (PODEX) (California, early 2013) and Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS, California and Texas, summer 2013). Our role in these efforts has been to serve as an assessment team performing level 1 (calibrated radiance, polarization) and level 2 (retrieved geophysical parameter) instrument intercomparisons, and to promote unified and generalized calibration, uncertainty assessment and retrieval techniques. We will present our progress in this endeavor thus far and describe upcoming research in 2015.

  10. Cloud retrieval algorithm for the imaging spectro-polarimeter on board EUMETSAT Polar System - Second Generation (EPS-SG)

    NASA Astrophysics Data System (ADS)

    Kokhanovsky, Alexander; Munro, Rose

    2015-04-01

    The atmospheric remote sensing benefits a lot from the use of spectro - polarimetric imagers on board satellite platforms. Due to the movement of the spacecraft, any given scene can be observed from many directions by an imaging polarimeter. This concept has been proven with the measurements of POLDER - 1, 2, and 3 on board ADEOS and PARASOL platforms. POLDER has performed measurements of the Stokes vector (first three components) of reflected light in 16 directions at several wavelengths in the visible and near - infrared. The 3MI (Multi-viewing, Multi-channel, Multi-polarization Imaging) on board of a future (2021) EPS-SG mission is very similar to POLDER. However, the measurements are performed at more spectral channels as compared to POLDER and also at a better spatial resolution (4*4km). In particular, the measurements of the Stokes vector components (I, Q, U) of the reflected solar light are performed at the wavelengths 410, 443, 490, 555, 670, 865, 1650, and 2130nm. In addition, the intensity of reflected light is measured at 763, 765, 910, and 1370nm. The FWHM of the channel at 763nm is 10nm and it is 20 nm at other channels (except at 765nm, 865nm, 1650nm, and 2130nm, where FWHM is equal to 40nm). The imaging spectro-polarimeter enables enhanced retrievals of aerosol and cloud properties using spaceborne observations. In particular, the following parameters of clouds can be retrieved: cloud top altitude, liquid water path, the average size of particles in the clouds, and the cloud thermodynamic state. The cloud albedo, cloud optical thickness, single scattering albedo and other optical parameters of clouds can be derived as well. In this presentation we describe the cloud retrieval algorithm CROP developed at EUMETSAT for the retrievals of cloud microphysical, geometrical, and optical characteristics using 3MI observations. The retrievals are performed only for completely cloudy pixels. The measurements at channels 763 and 765nm are used to get cloud top

  11. Application of Aeroelastic Solvers Based on Navier Stokes Equations

    NASA Technical Reports Server (NTRS)

    Keith, Theo G., Jr.; Srivastava, Rakesh

    2001-01-01

    The propulsion element of the NASA Advanced Subsonic Technology (AST) initiative is directed towards increasing the overall efficiency of current aircraft engines. This effort requires an increase in the efficiency of various components, such as fans, compressors, turbines etc. Improvement in engine efficiency can be accomplished through the use of lighter materials, larger diameter fans and/or higher-pressure ratio compressors. However, each of these has the potential to result in aeroelastic problems such as flutter or forced response. To address the aeroelastic problems, the Structural Dynamics Branch of NASA Glenn has been involved in the development of numerical capabilities for analyzing the aeroelastic stability characteristics and forced response of wide chord fans, multi-stage compressors and turbines. In order to design an engine to safely perform a set of desired tasks, accurate information of the stresses on the blade during the entire cycle of blade motion is required. This requirement in turn demands that accurate knowledge of steady and unsteady blade loading is available. To obtain the steady and unsteady aerodynamic forces for the complex flows around the engine components, for the flow regimes encountered by the rotor, an advanced compressible Navier-Stokes solver is required. A finite volume based Navier-Stokes solver has been developed at Mississippi State University (MSU) for solving the flow field around multistage rotors. The focus of the current research effort, under NASA Cooperative Agreement NCC3- 596 was on developing an aeroelastic analysis code (entitled TURBO-AE) based on the Navier-Stokes solver developed by MSU. The TURBO-AE code has been developed for flutter analysis of turbomachine components and delivered to NASA and its industry partners. The code has been verified. validated and is being applied by NASA Glenn and by aircraft engine manufacturers to analyze the aeroelastic stability characteristics of modem fans, compressors

  12. Numerical solution of the Navier-Stokes equations for unsteady separated flows

    NASA Astrophysics Data System (ADS)

    Hankey, W. L.

    By use of the time-dependent Navier-Stokes equations, simplifying assumptions are no longer necessary to investigate many classes of unsteady separated flows. The projected advancement of computer capability over the next few years renders questionable the wisdom of supporting basic research on short-cut approximate methods for analyzing unsteady separated flows.

  13. Turbomachinery Heat Transfer and Loss Modeling for 3D Navier-Stokes Codes

    NASA Technical Reports Server (NTRS)

    DeWitt, Kenneth; Ameri, Ali

    2005-01-01

    This report's contents focus on making use of NASA Glenn on-site computational facilities,to develop, validate, and apply models for use in advanced 3D Navier-Stokes Computational Fluid Dynamics (CFD) codes to enhance the capability to compute heat transfer and losses in turbomachiney.

  14. Modeling Systematic Error Effects for a Sensitive Storage Ring EDM Polarimeter

    NASA Astrophysics Data System (ADS)

    Stephenson, Edward; Imig, Astrid

    2009-10-01

    The Storage Ring EDM Collaboration has obtained a set of measurements detailing the sensitivity of a storage ring polarimeter for deuterons to small geometrical and rate changes. Various schemes, such as the calculation of the cross ratio [1], can cancel effects due to detector acceptance differences and luminosity differences for states of opposite polarization. Such schemes fail at second-order in the errors, becoming sensitive to geometrical changes, polarization magnitude differences between opposite polarization states, and changes to the detector response with changing data rates. An expansion of the polarimeter response in a Taylor series based on small errors about the polarimeter operating point can parametrize such effects, primarily in terms of the logarithmic derivatives of the cross section and analyzing power. A comparison will be made to measurements obtained with the EDDA detector at COSY-J"ulich. [4pt] [1] G.G. Ohlsen and P.W. Keaton, Jr., NIM 109, 41 (1973).

  15. MHD marking using the MSE polarimeter optics in ILW JET plasmas.

    PubMed

    Reyes Cortes, S; Alper, B; Alves, D; Baruzzo, M; Bernardo, J; Buratti, P; Coelho, R; Challis, C; Chapman, I; Hawkes, N; Hender, T C; Hobirk, J; Joffrin, E

    2016-11-01

    In this communication we propose a novel diagnostic technique, which uses the collection optics of the JET Motional Stark Effect (MSE) diagnostic, to perform polarimetry marking of observed MHD in high temperature plasma regimes. To introduce the technique, first we will present measurements of the coherence between MSE polarimeter, electron cyclotron emission, and Mirnov coil signals aiming to show the feasibility of the method. The next step consists of measuring the amplitude fluctuation of the raw MSE polarimeter signals, for each MSE channel, following carefully the MHD frequency on Mirnov coil data spectrograms. A variety of experimental examples in JET ITER-Like Wall (ILW) plasmas are presented, providing an adequate picture and interpretation for the MSE optics polarimeter technique.

  16. MHD marking using the MSE polarimeter optics in ILW JET plasmas

    NASA Astrophysics Data System (ADS)

    Reyes Cortes, S.; Alper, B.; Alves, D.; Baruzzo, M.; Bernardo, J.; Buratti, P.; Coelho, R.; Challis, C.; Chapman, I.; Hawkes, N.; Hender, T. C.; Hobirk, J.; Joffrin, E.

    2016-11-01

    In this communication we propose a novel diagnostic technique, which uses the collection optics of the JET Motional Stark Effect (MSE) diagnostic, to perform polarimetry marking of observed MHD in high temperature plasma regimes. To introduce the technique, first we will present measurements of the coherence between MSE polarimeter, electron cyclotron emission, and Mirnov coil signals aiming to show the feasibility of the method. The next step consists of measuring the amplitude fluctuation of the raw MSE polarimeter signals, for each MSE channel, following carefully the MHD frequency on Mirnov coil data spectrograms. A variety of experimental examples in JET ITER-Like Wall (ILW) plasmas are presented, providing an adequate picture and interpretation for the MSE optics polarimeter technique.

  17. THE IMAGING PROPERTIES OF THE GAS PIXEL DETECTOR AS A FOCAL PLANE POLARIMETER

    SciTech Connect

    Fabiani, S.; Costa, E.; Del Monte, E.; Muleri, F.; Soffitta, P.; Rubini, A.; Bellazzini, R.; Brez, A.; De Ruvo, L.; Minuti, M.; Pinchera, M.; Sgró, C.; Spandre, G.; Spiga, D.; Tagliaferri, G.; Pareschi, G.; Basso, S.; Citterio, O.; Burwitz, V.; Burkert, W.; and others

    2014-06-01

    X-rays are particularly suited to probing the physics of extreme objects. However, despite the enormous improvements of X-ray astronomy in imaging, spectroscopy, and timing, polarimetry remains largely unexplored. We propose the photoelectric polarimeter Gas Pixel Detector (GPD) as a candidate instrument to fill the gap created by more than 30 yr without measurements. The GPD, in the focus of a telescope, will increase the sensitivity of orders of magnitude. Moreover, since it can measure the energy, the position, the arrival time, and the polarization angle of every single photon, it allows us to perform polarimetry of subsets of data singled out from the spectrum, the light curve, or an image of the source. The GPD has an intrinsic, very fine imaging capability, and in this work we report on the calibration campaign carried out in 2012 at the PANTER X-ray testing facility of the Max-Planck-Institut für extraterrestrische Physik of Garching (Germany) in which, for the first time, we coupled it with a JET-X optics module with a focal length of 3.5 m and an angular resolution of 18 arcsec at 4.5 keV. This configuration was proposed in 2012 aboard the X-ray Imaging Polarimetry Explorer (XIPE) in response to the ESA call for a small mission. We derived the imaging and polarimetric performance for extended sources like pulsar wind nebulae and supernova remnants as case studies for the XIPE configuration and also discuss possible improvements by coupling the detector with advanced optics that have a finer angular resolution and larger effective areas to study extended objects with more detail.

  18. Stokes and anti-stokes stimulated Mie scattering on nanoparticle suspensions of latex

    NASA Astrophysics Data System (ADS)

    Burkhanov, I. S.; Krivokhizha, S. V.; Chaikov, L. L.

    2016-12-01

    Stokes and anti-Stokes shifts of stimulated concentration light scattering (SCLS, stimulated Mie scattering) in suspensions of various-sized latex nanoparticles in water were measured by the light guide scheme, under conditions of backscattering in the presence of convection.

  19. Bandwidth and Noise in Spatiotemporally Modulated Mueller Matrix Polarimeters

    NASA Astrophysics Data System (ADS)

    Vaughn, Israel Jacob

    improved by 300% over a conventional dual rotating retarder Mueller matrix polarimeter. Reconstruction results from the physical instrument are presented, and issues with the implemented system design are discussed.

  20. Absolute polarimeter for the proton-beam energy of 200 MeV

    SciTech Connect

    Zelenski, A. N.; Atoian, G.; Bogdanov, A. A.; Nurushev, S. B.; Pylaev, F. S.; Raparia, D.; Runtso, M. F.; Stephenson, E.

    2013-12-15

    A polarimeter is upgraded and tested in a 200-MeV polarized-proton beam at the accelerator-collider facility of the Brookhaven National Laboratory. The polarimeter is based on the elastic polarizedproton scattering on a carbon target at an angle of 16.2°, in which case the analyzing power is close to unity and was measured to a very high degree of precision. It is shown that, in the energy range of 190–205 MeV, the absolute polarization can be measured to a precision better than ±0.5%.

  1. Multilayer based soft-x-ray polarimeter at MAX IV Laboratory

    SciTech Connect

    Grizolli, Walan; Laksman, Joakim; Hennies, Franz; Jensen, Brian Norsk; Nyholm, Ralf; Sankari, Rami

    2016-02-15

    A high precision five rotation-axes polarimeter using transmission multilayers as polarizers and reflection multilayers as analyzers has been designed and manufactured. To cover the extreme ultraviolet regime, Mo/Si, Cr/C, Sc/Cr, and W/B{sub 4}C multilayers for transmission and reflection have also been designed and produced. The polarimeter mechanics is supported on a hexapod to simplify the alignment relative to photon beam. The instrument is designed so that it can be easily transferred between different beamlines.

  2. Multilayer based soft-x-ray polarimeter at MAX IV Laboratory

    NASA Astrophysics Data System (ADS)

    Grizolli, Walan; Laksman, Joakim; Hennies, Franz; Jensen, Brian Norsk; Nyholm, Ralf; Sankari, Rami

    2016-02-01

    A high precision five rotation-axes polarimeter using transmission multilayers as polarizers and reflection multilayers as analyzers has been designed and manufactured. To cover the extreme ultraviolet regime, Mo/Si, Cr/C, Sc/Cr, and W/B4C multilayers for transmission and reflection have also been designed and produced. The polarimeter mechanics is supported on a hexapod to simplify the alignment relative to photon beam. The instrument is designed so that it can be easily transferred between different beamlines.

  3. Measurement of the nuclear polarization of hydrogen and deuterium molecules using a Lamb-shift polarimeter

    SciTech Connect

    Engels, Ralf Gorski, Robert; Grigoryev, Kiril; Mikirtychyants, Maxim; Rathmann, Frank; Seyfarth, Hellmut; Ströher, Hans; Weiss, Philipp; Kochenda, Leonid; Kravtsov, Peter; Trofimov, Viktor; Tschernov, Nikolay; Vasilyev, Alexander; Vznuzdaev, Marat; Schieck, Hans Paetz gen.

    2014-10-15

    Lamb-shift polarimeters are used to measure the nuclear polarization of protons and deuterons at energies of a few keV. In combination with an ionizer, the polarization of hydrogen and deuterium atoms was determined after taking into account the loss of polarization during the ionization process. The present work shows that the nuclear polarization of hydrogen or deuterium molecules can be measured as well, by ionizing the molecules and injecting the H{sub 2}{sup +} (or D{sub 2}{sup +}) ions into the Lamb-shift polarimeter.

  4. A precise in situ calibration of the RHIC H-Jet polarimeter

    SciTech Connect

    Poblaguev, A. A.

    2014-03-05

    Two new methods of calibration of the hydrogen jet target polarimeter (H-Jet) at RHIC are discussed. First method is based on the measurement of low amplitude signal time of fast particles penetrating through detector. The second, geometry based, method employs correlation between z-coordinate of the recoil proton and its kinetic energy. Both methods can be used for in situ calibration of the H-Jet polarimeter. These two methods are compared with a traditional calibration of the H-Jet which uses α-sources.

  5. Status of the Stellar X-Ray Polarimeter for the Spectrum-X-Gamma mission

    NASA Technical Reports Server (NTRS)

    Kaaret, P.; Novick, R.; Shaw, P.; Hanany, S.; Liu, Y.; Fleischman, J. R.; Siuniaev, R.; Lapshov, I.; Weisskopf, M. C.; Elsner, R. F.

    1991-01-01

    The Stellar X-Ray Polarimeter (SXRP) uses the polarization sensitivity of a graphite Bragg crystal and a lithium Thomsom scattering target to measure the polarization of X-rays from astrophysical sources. The SXRP is a focal plane detector for the Soviet-Danish SODART telescopes which will be launched on the Soviet Spectrum-X-Gamma mission. The SXRP will be the third orbiting stellar X-ray polarimeter, and should provide an order of magnitude increase in polarization sensitivity over its predecessors.

  6. High-precision polarimetry at the Mont-Mégantic Observatory with the new polarimeter POMM

    NASA Astrophysics Data System (ADS)

    Bastien, Pierre; Hernandez, Olivier; Albert, Loïc.; Artigau, Étienne; Doyon, René; Drissen, Laurent; Lafrenière, David; Moffat, Antony F. J.; St-Louis, Nicole

    2014-07-01

    A new polarimeter has been built for the "Observatoire du Mont-Mégantic" (POMM) and is now in commissioning phase. It will allow polarization measurements with a precision of 10-6, an improvement by a factor of 100 over the previous observatory polarimeter. The characteristics of the instrument that allow this goal are briefly discussed and the planned science observations are presented. They include exoplanets near their host star (hot Jupiters), transiting exoplanets, stars with debris disks, young stars with proto-planetary disks, brown dwarfs, massive Wolf-Rayet stars and comets. The details of the optical and mechanical designs are presented in two other papers.

  7. Measurement of the nuclear polarization of hydrogen and deuterium molecules using a Lamb-shift polarimeter.

    PubMed

    Engels, Ralf; Gorski, Robert; Grigoryev, Kiril; Mikirtychyants, Maxim; Rathmann, Frank; Seyfarth, Hellmut; Ströher, Hans; Weiss, Philipp; Kochenda, Leonid; Kravtsov, Peter; Trofimov, Viktor; Tschernov, Nikolay; Vasilyev, Alexander; Vznuzdaev, Marat; Paetz gen Schieck, Hans

    2014-10-01

    Lamb-shift polarimeters are used to measure the nuclear polarization of protons and deuterons at energies of a few keV. In combination with an ionizer, the polarization of hydrogen and deuterium atoms was determined after taking into account the loss of polarization during the ionization process. The present work shows that the nuclear polarization of hydrogen or deuterium molecules can be measured as well, by ionizing the molecules and injecting the H2(+) (or D2(+)) ions into the Lamb-shift polarimeter.

  8. Stokes efficiency and its stochastic properties

    NASA Astrophysics Data System (ADS)

    Sahoo, Mamata; Jayannavar, A. M.

    2017-01-01

    We study the Stokes efficiency and its fluctuating properties in the case of a spatial asymmetric ratchet potential with a temporal asymmetric driving force from adiabatic to nonadiabatic regime. Our numerical investigations show that the average Stokes efficiency and the average current decrease with increase in the frequency of driving. For low frequency of driving, i.e., in the case of an adiabatic regime, we reproduced the analytical results supporting our numerical simulations. By evaluating the probability distribution p(ηs) for Stokes efficiency ηs, we focus on the stochastic properties of Stokes efficiency. We find that in most of the parameter space, fluctuations in ηs are comparable to or larger than the mean values. In such a situation, one has to study the nature of the full probability distribution of ηs. We observe that with increase in frequency of driving, the distribution becomes multipeaked. At the same time, the average Stokes efficiency monotonically decreases with increase in frequency of the drive. For high frequency of driving, the distribution develops a peak at zero. With further increase in frequency of the drive this peak gets sharper. And finally at sufficiently high frequency, we get a strong peak at zero indicating that there is no effective transport in this regime.

  9. Multistaged stokes injected Raman capillary waveguide amplifier

    DOEpatents

    Kurnit, Norman A.

    1980-01-01

    A multistaged Stokes injected Raman capillary waveguide amplifier for providing a high gain Stokes output signal. The amplifier uses a plurality of optically coupled capillary waveguide amplifiers and one or more regenerative amplifiers to increase Stokes gain to a level sufficient for power amplification. Power amplification is provided by a multifocused Raman gain cell or a large diameter capillary waveguide. An external source of CO.sub.2 laser radiation can be injected into each of the capillary waveguide amplifier stages to increase Raman gain. Devices for injecting external sources of CO.sub.2 radiation include: dichroic mirrors, prisms, gratings and Ge Brewster plates. Alternatively, the CO.sub.2 input radiation to the first stage can be coupled and amplified between successive stages.

  10. About the Regularized Navier Stokes Equations

    NASA Astrophysics Data System (ADS)

    Cannone, Marco; Karch, Grzegorz

    2005-03-01

    The first goal of this paper is to study the large time behavior of solutions to the Cauchy problem for the 3-dimensional incompressible Navier Stokes system. The Marcinkiewicz space L3,∞ is used to prove some asymptotic stability results for solutions with infinite energy. Next, this approach is applied to the analysis of two classical “regularized” Navier Stokes systems. The first one was introduced by J. Leray and consists in “mollifying” the nonlinearity. The second one was proposed by J.-L. Lions, who added the artificial hyper-viscosity (-Δ)ℓ/ 2, ℓ > 2 to the model. It is shown in the present paper that, in the whole space, solutions to those modified models converge as t → ∞ toward solutions of the original Navier Stokes system.

  11. Full Stokes glacier model on GPU

    NASA Astrophysics Data System (ADS)

    Licul, Aleksandar; Herman, Frédéric; Podladchikov, Yuri; Räss, Ludovic; Omlin, Samuel

    2015-04-01

    Two different approaches are commonly used in glacier ice flow modeling: models based on asymptotic approximations of ice physics and full stokes models. Lower order models are computationally lighter but reach their limits in regions of complex flow, while full Stokes models are more exact but computationally expansive. To overcome this constrain, we investigate the potential of GPU acceleration in glacier modeling. The goal of this preliminary research is to develop a three-dimensional full Stokes numerical model and apply it to the glacier flow. We numerically solve the nonlinear Stokes momentum balance equations together with the incompressibility equation. Strong nonlinearities for the ice rheology are also taken into account. We have developed a fully three-dimensional numerical MATLAB application based on an iterative finite difference scheme. We have ported it to C-CUDA to run it on GPUs. Our model is benchmarked against other full Stokes solutions for all diagnostic ISMIP-HOM experiments (Pattyn et al.,2008). The preliminary results show good agreement with the other models. The major advantages of our programming approach are simplicity and order 10-100 times speed-up in comparison to serial CPU version of the code. Future work will include some real world applications and we will implement the free surface evolution capabilities. References: [1] F. Pattyn, L. Perichon, A. Aschwanden, B. Breuer, D.B. Smedt, O. Gagliardini, G.H. Gudmundsson, R.C.A. Hindmarsh, A. Hubbard, J.V. Johnson, T. Kleiner, Y. Konovalov, C. Martin, A.J. Payne, D. Pollard, S. Price, M. Ruckamp, F. Saito, S. Sugiyama, S., and T. Zwinger, Benchmark experiments for higher-order and full-Stokes ice sheet models (ISMIP-HOM), The Cryosphere, 2 (2008), 95-108.

  12. Generalized Stokes parameters in phase space.

    PubMed

    Sahin, Serkan

    2010-05-15

    The generalized Stokes parameters (GSP) are studied under the theory of phase space. It is noted that phase-space Stokes parameters can be a useful tool for Wigner distribution function measurements. Electromagnetic Wigner functions are introduced by use of the two-point statistics of GSP. The advantage in the GSP is that they can be measured in terms of the electric correlation matrix (which is a measurable quantity) or they can be measured independently. Hence, the GSP help in finding the polarization and coherence properties of electromagnetic beams. Within this framework, by using the GSP in phase space, the intensity feature of electromagnetic beams in phase space is given, as well.

  13. Direct Comparison of Møller and Compton Polarimeters in Hall C at Jefferson Lab

    NASA Astrophysics Data System (ADS)

    Gaskell, Dave

    2017-01-01

    Knowledge of the electron beam polarization is one of the most important systematic uncertainties in precision, parity-violating electron scattering experiments with next generation experiments aiming to measure the electron beam polarization to better than 0.5%. At high energies, the most typical polarimetry techniques are Møller (polarized electron-electron) and Compton (polarized electron-photon) scattering. The use of two techniques with different systematic uncertainties provides confidence in the extracted beam polarization. Direct comparisons of the two polarimetry techniques are challenging in that Compton polarimeters typically desire maximum beam flux (high beam currents) while Møller polarimeters need to limit the beam current to avoid depolarization effects in the target. We have performed a direct comparison of the Møller and Compton polarimeters in experimental Hall C at Jefferson Lab. This test is unique in that the data were taken sequentially under identical beam conditions at 4.5 μA. We found excellent agreement between the Hall C Møller and Compton polarimeters. Combined with high-current Compton data, we were also able to limit the beam current dependence of the beam polarization to 1% or less up to a beam current of 180 μA. Supported in part by the U.S. Deparment of Energy, contract number AC05-06OR23177, under which Jefferson Science Associates, LLC operates Thomas Jefferson National Accelerator Facility.

  14. SOLPOL: A Solar Polarimeter for Hard X-Rays and Gamma-Rays

    NASA Technical Reports Server (NTRS)

    McConnell, Michael L.

    1999-01-01

    Th goal of this project was to continue the development of a hard X-ray polarimeter for studying solar flares. In earlier work (funded by a previous SR&T grant), we had already achieved several goals, including the following: 1) development of a means of producing a polarized radiation source in the lab that could be used for prototype development; 2) demonstrated the basic Compton scatter polarimeter concept using a simple laboratory setup; 3) used the laboratory results to verify our Monte Carlo simulations; and 4) investigated various detector technologies that could be incorporated into the polarimeter design. For the current one-year program, we wanted to fabricate and test a laboratory science model based on our SOLPOL (Solar Polarimeter) design. The long-term goal of this effort is to develop and test a prototype design that could be used to study flare emissions from either a balloon- or space-borne platform. The current program has achieved its goal of fabricating and testing a science model of the SOLPOL design, although additional testing of the design (and detailed comparison with Monte Carlo simulations) is still desired. This one-year program was extended by six months (no-cost extension) to cover the summer of 1999, when undergraduate student support was available to complete some of the laboratory testing.

  15. Exploring a possible origin of a 14 deg y-normal spin tilt at RHIC polarimeter

    SciTech Connect

    Meot, F.; Huang, H.

    2015-06-15

    A possible origin of a 14 deg y-normal spin n0 tilt at the polarimeter is in snake angle defects. This possible cause is investigated by scanning the snake axis angle µ, and the spin rotation angle at the snake, φ, in the vicinity of their nominal values.

  16. Active Metamaterial Based Terahertz Polarimeter for Spectroscopic Detection of Chemical and Biological Hazards

    DTIC Science & Technology

    2014-04-01

    Active Metamaterial Based Terahertz Polarimeter for Spectroscopic Detection of Chemical and Biological Hazards by Grace D. Metcalfe ...for Spectroscopic Detection of Chemical and Biological Hazards Grace D. Metcalfe and Michael Wraback Sensors and Electron Devices Directorate, ARL...GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Grace D. Metcalfe , Michael Wraback, Richard D. Averitt, and Xin Zhang 5d. PROJECT NUMBER

  17. A Technique for Simultansous Measurement of Circular and Linear Polarization with a Single-Channel Polarimeter

    NASA Astrophysics Data System (ADS)

    Kolesnikov, S. V.; Breus, V. V.; Kiselev, N. N.; Andronov, I. L.

    We present a technique for simultaneous measurement of circular and linear polarization with the single-channel polarimeter, that is used in Crimean astrophysical observatory for many years. Methods and a computer program for data reduction is described. The algorithm is described, which have been used for photo-polarimetric monitoring of various astronomical objects cataclysmic variables, asteroids, comets.

  18. Stochastic nonhomogeneous incompressible Navier-Stokes equations

    NASA Astrophysics Data System (ADS)

    Cutland, Nigel J.; Enright, Brendan

    We construct solutions for 2- and 3-D stochastic nonhomogeneous incompressible Navier-Stokes equations with general multiplicative noise. These equations model the velocity of a mixture of incompressible fluids of varying density, influenced by random external forces that involve feedback; that is, multiplicative noise. Weak solutions for the corresponding deterministic equations were first found by Kazhikhov [A.V. Kazhikhov, Solvability of the initial and boundary-value problem for the equations of motion of an inhomogeneous viscous incompressible fluid, Soviet Phys. Dokl. 19 (6) (1974) 331-332; English translation of the paper in: Dokl. Akad. Nauk SSSR 216 (6) (1974) 1240-1243]. A stochastic version with additive noise was solved by Yashima [H.F. Yashima, Equations de Navier-Stokes stochastiques non homogènes et applications, Thesis, Scuola Normale Superiore, Pisa, 1992]. The methods here extend the Loeb space techniques used to obtain the first general solutions of the stochastic Navier-Stokes equations with multiplicative noise in the homogeneous case [M. Capiński, N.J. Cutland, Stochastic Navier-Stokes equations, Applicandae Math. 25 (1991) 59-85]. The solutions display more regularity in the 2D case. The methods also give a simpler proof of the basic existence result of Kazhikhov.

  19. Stokes Equation in a Toy CD Hovercraft

    ERIC Educational Resources Information Center

    de Izarra, Charles; de Izarra, Gregoire

    2011-01-01

    This paper deals with the study of a toy CD hovercraft used in the fluid mechanics course for undergraduate students to illustrate the lubrication theory described by the Stokes equation. An experimental characterization of the toy hovercraft (measurements of the air flow value, of the pressure in the balloon and of the thickness of the air film…

  20. Stokely Carmichael: The Story of Black Power.

    ERIC Educational Resources Information Center

    Johnson, Jacqueline

    This biography for younger readers presents the life of Stokely Carmichael, who made famous the phrase "Black Power" as he fought for the rights of black people in the United States and who later settled in Africa, where he organizes young Africans to work for their rights. The book is introduced by an overview of the civil rights…

  1. The Classical Version of Stokes' Theorem Revisited

    ERIC Educational Resources Information Center

    Markvorsen, Steen

    2008-01-01

    Using only fairly simple and elementary considerations--essentially from first year undergraduate mathematics--we show how the classical Stokes' theorem for any given surface and vector field in R[superscript 3] follows from an application of Gauss' divergence theorem to a suitable modification of the vector field in a tubular shell around the…

  2. Observation of anomalous Stokes versus anti-Stokes ratio in MoTe2 atomic layers

    NASA Astrophysics Data System (ADS)

    Goldstein, Thomas; Chen, Shao-Yu; Xiao, Di; Ramasubramaniam, Ashwin; Yan, Jun

    We grow hexagonal molybdenum ditelluride (MoTe2), a prototypical transition metal dichalcogenide (TMDC) semiconductor, with chemical vapor transport methods and investigate its atomic layers with Stokes and anti-Stokes Raman scattering. We report observation of all six types of zone center optical phonons. Quite remarkably, the anti-Stokes Raman intensity of the low energy layer-breathing mode becomes more intense than the Stokes peak under certain experimental conditions, creating an illusion of 'negative temperature'. This effect is tunable, and can be switched from anti-Stokes enhancement to suppression by varying the excitation wavelength. We interpret this observation to be a result of resonance effects arising from the C excitons in the vicinity of the Brillouin zone center, which are robust even for multiple layers of MoTe2. The intense anti-Stokes Raman scattering provides a cooling channel for the crystal and opens up opportunities for laser cooling of atomically thin TMDC semiconductor devices. Supported by the University of Massachusetts Amherst, the National Science Foundation Center for Hierarchical Manufacturing (CMMI-1025020) and Office of Emerging Frontiers in Research and Innovation (EFRI-1433496).

  3. Compact and robust linear Stokes polarization camera

    NASA Astrophysics Data System (ADS)

    Vedel, M.; Lechocinski, N.; Breugnot, S.

    2010-06-01

    We present novel applications of Bossa Nova Technologies Linear Stokes polarization camera. The SALSA camera is able to perform live measurement of Linear Stokes parameters, usual polarization parameters (Degree Of Linear Polarization and Angle Of Polarization) and other polarization based parameters (polarized image, depolarized image, virtual polarizer, polarization difference). First a brief description of the SALSA camera and its calibration is given. Then we present and discuss several results of target detection and contrast enhancement experiments. We will also introduce a novel polarization based metrological method of 3D shape measurement for in-line control of optical surfaces and control of highly aspheric optical surfaces. The architecture of the hardware and calibration results is presented. A new algorithm based on polarization imaging leading to the construction of the gradient field is described. Finally experimental results and observations as well as possible further steps are discussed.

  4. Initial measurements of plasma current and electron density profiles using a polarimeter/interferometer (POINT) for long pulse operation in EAST (invited).

    PubMed

    Liu, H Q; Qian, J P; Jie, Y X; Ding, W X; Brower, D L; Zou, Z Y; Li, W M; Lian, H; Wang, S X; Yang, Y; Zeng, L; Lan, T; Yao, Y; Hu, L Q; Zhang, X D; Wan, B N

    2016-11-01

    A double-pass, radially viewing, far-infrared laser-based POlarimeter-INTerferometer (POINT) system utilizing the three-wave technique has been implemented for diagnosing the plasma current and electron density profiles in the Experimental Advanced Superconducting Tokamak (EAST). POINT has been operated routinely during the most recent experimental campaign and provides continuous 11 chord line-integrated Faraday effect and density measurement throughout the entire plasma discharge for all heating schemes and all plasma conditions (including ITER relevant scenario development). Reliability of both the polarimetric and interferometric measurements is demonstrated in 25 s plasmas with H-mode and 102 s long-pulse discharges. Current density, safety factor (q), and electron density profiles are reconstructed using equilibrium fitting code (EFIT) with POINT constraints for the plasma core.

  5. Initial measurements of plasma current and electron density profiles using a polarimeter/interferometer (POINT) for long pulse operation in EAST (invited)

    NASA Astrophysics Data System (ADS)

    Liu, H. Q.; Qian, J. P.; Jie, Y. X.; Ding, W. X.; Brower, D. L.; Zou, Z. Y.; Li, W. M.; Lian, H.; Wang, S. X.; Yang, Y.; Zeng, L.; Lan, T.; Yao, Y.; Hu, L. Q.; Zhang, X. D.; Wan, B. N.

    2016-11-01

    A double-pass, radially viewing, far-infrared laser-based POlarimeter-INTerferometer (POINT) system utilizing the three-wave technique has been implemented for diagnosing the plasma current and electron density profiles in the Experimental Advanced Superconducting Tokamak (EAST). POINT has been operated routinely during the most recent experimental campaign and provides continuous 11 chord line-integrated Faraday effect and density measurement throughout the entire plasma discharge for all heating schemes and all plasma conditions (including ITER relevant scenario development). Reliability of both the polarimetric and interferometric measurements is demonstrated in 25 s plasmas with H-mode and 102 s long-pulse discharges. Current density, safety factor (q), and electron density profiles are reconstructed using equilibrium fitting code (EFIT) with POINT constraints for the plasma core.

  6. Automatic differentiation and Navier-Stokes.

    SciTech Connect

    Bischof, C.; Hovland, P.; Mohammadi, B.

    1997-12-17

    We describe the use of automatic differentiation (AD) to enhance a compressible Navier-Stokes model. With the solver, AD is used to accelerate convergence by more than an order of magnitude. Outside the solver, AD is used to compute the derivatives needed for optimization. We emphasize the potential for performance gains if the programmer does not treat AD as a black box, but instead utilizes high-level knowledge about the nature of the application.

  7. Vorticity, Stokes' Theorem and the Gauss's Theorem

    NASA Astrophysics Data System (ADS)

    Narayanan, M.

    2004-12-01

    Vorticity is a property of the flow of any fluid and moving fluids acquire properties that allow an engineer to describe that particular flow in greater detail. It is important to recognize that mere motion alone does not guarantee that the air or any fluid has vorticity. Vorticity is one of four important quantities that define the kinematic properties of any fluid flow. The Navier-Stokes equations are the foundation of fluid mechanics, and Stokes' theorem is used in nearly every branch of mechanics as well as electromagnetics. Stokes' Theorem also plays a vital role in many secondary theorems such as those pertaining to vorticity and circulation. However, the divergence theorem is a mathematical statement of the physical fact that, in the absence of the creation or destruction of matter, the density within a region of space can change only by having it flow into, or away from the region through its boundary. This is also known as Gauss's Theorem. It should also be noted that there are many useful extensions of Gauss's Theorem, including the extension to include surfaces of discontinuity in V. Mathematically expressed, Stokes' theorem can be expressed by considering a surface S having a bounding curve C. Here, V is any sufficiently smooth vector field defined on the surface and its bounding curve C. Integral (Surface) [(DEL X V)] . dS = Integral (Contour) [V . dx] In this paper, the author outlines and stresses the importance of studying and teaching these mathematical techniques while developing a course in Hydrology and Fluid Mechanics. References Arfken, G. "Gauss's Theorem." 1.11 in Mathematical Methods for Physicists, 3rd ed. Orlando, FL: Academic Press, pp. 57-61, 1985. Morse, P. M. and Feshbach, H. "Gauss's Theorem." In Methods of Theoretical Physics, Part I. New York: McGraw-Hill, pp. 37-38, 1953. Eric W. Weisstein. "Divergence Theorem." From MathWorld--A Wolfram Web Resource. http://mathworld.wolfram.com/DivergenceTheorem.html

  8. Stokes injected Raman capillary waveguide amplifier

    DOEpatents

    Kurnit, Norman A.

    1980-01-01

    A device for producing stimulated Raman scattering of CO.sub.2 laser radiation by rotational states in a diatomic molecular gas utilizing a Stokes injection signal. The system utilizes a cryogenically cooled waveguide for extending focal interaction length. The waveguide, in conjunction with the Stokes injection signal, reduces required power density of the CO.sub.2 radiation below the breakdown threshold for the diatomic molecular gas. A Fresnel rhomb is employed to circularly polarize the Stokes injection signal and CO.sub.2 laser radiation in opposite circular directions. The device can be employed either as a regenerative oscillator utilizing optical cavity mirrors or as a single pass amplifier. Additionally, a plurality of Raman gain cells can be staged to increase output power magnitude. Also, in the regenerative oscillator embodiment, the Raman gain cell cavity length and CO.sub.2 cavity length can be matched to provide synchronism between mode locked CO.sub.2 pulses and pulses produced within the Raman gain cell.

  9. Stokes parameters modulator for birefringent filters

    NASA Technical Reports Server (NTRS)

    Dollfus, A.

    1985-01-01

    The Solar Birefringent Filter (Filter Polarisiant Solaire Selectif FPSS) of Meudon Observatory is presently located at the focus of a solar refractor with a 28 cm lens directly pointed at the Sun. It produces a diffraction limited image without instrumental polarization and with a spectral resolution of 46,000 in a field of 6 arc min. diameter. The instrument is calibrated for absolute Doppler velocity measurements and is presently used for quantitative imagery of the radial velocity motions in the photosphere. The short period oscillations are recorded. Work of adapting the instrument for the imagery of the solar surface in the Stokes parameters is discussed. The first polarizer of the birefringent filter, with a reference position angle 0 deg, is associated with a fixed quarter wave plate at +45 deg. A rotating quarter wave plate is set at 0 deg and can be turned by incremented steps of exactly +45 deg. Another quarter wave plate also initially set at 0 deg is simultaneously incremented by -45 deg but only on each even step of the first plate. A complete cycle of increments produces images for each of the 6 parameters I + or - Q, I + or - U and I + or - V. These images are then subtracted by pairs to produce a full image in the three Stokes parameters Q, U and V. With proper retardation tolerance and positioning accuracy of the quarter wave plates, the cross talk between the Stokes parameters was calculated and checked to be minimal.

  10. Incorporating Electrokinetic Phenomena into EBNavierStokes

    SciTech Connect

    Chu, K; Trebotich, D

    2006-01-10

    Motivated by the recent interest in using electrokinetic effects within microfluidic devices, they have extended the EBNavierStokes code to be able to handle electrokinetic effects. With this added functionality, the code becomes more useful for understanding and designing microfluidic devices that take advantage of electrokinetic effects (e.g. pumping and mixing). Supporting the simulation of electrokinetic effects required three main extensions to the existing code: (1) addition of an electric field solver, (2) development of a module for accurately computing the Smulochowski slip-velocity at fluid-solid boundaries, and (3) extension of the fluid solver to handle nonuniform inhomogeneous Dirichlet boundary conditions. The first and second extensions were needed to compute the electrokinetically generated slip-velocity at fluid-solid boundaries. The third extension made it possible for the fluid flow to be driven by a slip-velocity boundary condition (rather than by a pressure difference between inflow and outflow). In addition, several small changes were made throughout the code to make it compatible with these extensions. This report documents the changes to the EBNavierStokes code required to support the simulation of electrokinetic effects. They begin with a brief overview of the problem of electrokinetically driven flow. Next, they present a detailed description of the changes to the EBNavierStokes code. Finally, they present some preliminary results and discuss future directions and improvements to the code.

  11. Active Region Segmentation Based on Stokes Asymmetries

    NASA Astrophysics Data System (ADS)

    Choi, Jieun; Harker-Lundberg, B.

    2011-01-01

    During the Stokes inversion process, we would ideally use a distinct model for each structure in an active region which addresses the differences in the physical conditions of these regions. While the Milne-Eddington model of the atmosphere---a frequently-used ideal model that assumes all local thermodynamic equilibrium (LTE) conditions are satisfied---is a sufficient approximation for the description of the solar photosphere, we almost always observe deviations from this model. It is thus of interest to devise a method to systematically and accurately identify the active regions based on their spectra, such that we could use a more sophisticated model catered to each structure in an active region during the actual Stokes inversion process. We present a classification scheme for different active region structures using Stokes asymmetries and line core depths as discriminators. The data used for this investigation were obtained from the Synoptic Optical Long-term Investigations of the Sun (SOLIS) facility using the Vector Spectromagnetograph (VSM), observed in a 3 A bandpass around Fe I 6302.5 A, from March 27, 2008 to March 29, 2008. This work is carried out through the National Solar Observatory Research Experiences for Undergraduate (REU) site program, which is co-funded by the Department of Defense in partnership with the National Science Foundation REU Program. The National Solar Observatory is operated by the Association of Universities for Research in Astronomy, Inc. (AURA) under cooperative agreement with the National Science Foundation.

  12. The TJNAF Hall A M{umlt o}ller polarimeter

    SciTech Connect

    Dale, D.S.; Gasparian, A.; Doyle, B.; Gorringe, T.; Korsch, W.; Zeps, V.; Glamazdin, A.; Gorbenko, V.; Pomatsalyuk, R.; Chen, J.P.; Nanda, S.; Saha, A.

    1998-01-01

    As part of the spin physics program at Jefferson Lab, a M{umlt o}ller polarimeter is being developed to measure the polarization of electron beams of energies 0.8 to 6 GeV. The device uses electron-electron scattering in a set-up in which the polarized beam is scattered from a polarized electron target. A unique signature for M{umlt o}ller scattering is obtained using a series of three quadrupole magnets which provide angular selection, and a dipole magnet for energy analysis. Here, the design and commissioning of this polarimeter will be discussed along with future plans to use its small scattering angle capabilities to investigate physics in the very low q{sup 2} regime. {copyright} {ital 1998 American Institute of Physics.}

  13. A novel comparison of Møller and Compton electron-beam polarimeters

    NASA Astrophysics Data System (ADS)

    Magee, J. A.; Narayan, A.; Jones, D.; Beminiwattha, R.; Cornejo, J. C.; Dalton, M. M.; Deconinck, W.; Dutta, D.; Gaskell, D.; Martin, J. W.; Paschke, K. D.; Tvaskis, V.; Asaturyan, A.; Benesch, J.; Cates, G.; Cavness, B. S.; . A. Dillon-Townes, L.; Hays, G.; Hoskins, J.; Ihloff, E.; Jones, R.; King, P. M.; Kowalski, S.; Kurchaninov, L.; Lee, L.; McCreary, A.; McDonald, M.; Micherdzinska, A.; Mkrtchyan, A.; Mkrtchyan, H.; Nelyubin, V.; Page, S.; Ramsay, W. D.; Solvignon, P.; Storey, D.; Tobias, W. A.; Urban, E.; Vidal, C.; Waidyawansa, B.; Wang, P.; Zhamkotchyan, S.

    2017-03-01

    We have performed a novel comparison between electron-beam polarimeters based on Møller and Compton scattering. A sequence of electron-beam polarization measurements were performed at low beam currents (< 5 μA) during the Qweak experiment in Hall-C at Jefferson Lab. These low current measurements were bracketed by the regular high current (180 μA) operation of the Compton polarimeter. All measurements were found to be consistent within experimental uncertainties of 1% or less, demonstrating that electron polarization does not depend significantly on the beam current. This result lends confidence to the common practice of applying Møller measurements made at low beam currents to physics experiments performed at higher beam currents. The agreement between two polarimetry techniques based on independent physical processes sets an important benchmark for future precision asymmetry measurements that require sub-1% precision in polarimetry.

  14. Measurements of the Polarization Properties of Foam Materials Useful for mm-wave Polarimeters Windows

    NASA Astrophysics Data System (ADS)

    Coppi, G.; Marchetti, T.; de Bernardis, P.; Masi, S.

    2016-08-01

    We have measured in the W-band, using a custom setup, the absorption and polarization properties in transmission of foam materials (elyfoamⓇ, styrodurⓇ, plastazoteⓇ, and propozoteⓇ) useful for windows of mm-wave photometers and polarimeters. The levels of the induced polarization degree and of the absorption are very small, and difficult to measure accurately. We find induced polarization degrees lower than 0.6 %, and transmissions higher than 97 % for few centimeter thicknesses of our samples. We describe the instrumental setup, the measurements, and the impact of our findings in the design of precision polarimeters for Cosmic Microwave Background measurements. All these materials, with the exception of black plastazoteⓇ, feature transmissions higher than 99 %, and induced polarizations lower than ˜1 % for sample thicknesses around 2-3 cm.

  15. High-precision soft x-ray polarimeter at Diamond Light Source.

    PubMed

    Wang, H; Dhesi, S S; Maccherozzi, F; Cavill, S; Shepherd, E; Yuan, F; Deshmukh, R; Scott, S; van der Laan, G; Sawhney, K J S

    2011-12-01

    The development and performance of a high-precision polarimeter for the polarization analysis in the soft x-ray region is presented. This versatile, high-vacuum compatible instrument is supported on a hexapod to simplify the alignment with a resolution less than 5 μrad, and can be moved with its own independent control system easily between different beamlines and synchrotron facilities. The polarimeter can also be used for the characterization of reflection and transmission properties of optical elements. A W/B(4)C multilayer phase retarder was used to characterize the polarization state up to 1200 eV. A fast and accurate alignment procedure was developed, and complete polarization analysis of the APPLE II undulator at 712 eV has been performed.

  16. High-precision soft x-ray polarimeter at Diamond Light Source

    NASA Astrophysics Data System (ADS)

    Wang, H.; Dhesi, S. S.; Maccherozzi, F.; Cavill, S.; Shepherd, E.; Yuan, F.; Deshmukh, R.; Scott, S.; van der Laan, G.; Sawhney, K. J. S.

    2011-12-01

    The development and performance of a high-precision polarimeter for the polarization analysis in the soft x-ray region is presented. This versatile, high-vacuum compatible instrument is supported on a hexapod to simplify the alignment with a resolution less than 5 μrad, and can be moved with its own independent control system easily between different beamlines and synchrotron facilities. The polarimeter can also be used for the characterization of reflection and transmission properties of optical elements. A W/B4C multilayer phase retarder was used to characterize the polarization state up to 1200 eV. A fast and accurate alignment procedure was developed, and complete polarization analysis of the APPLE II undulator at 712 eV has been performed.

  17. Fabrication of optical components for the ultraviolet spectrometer and polarimeter on the Solar Maximum Mission

    NASA Technical Reports Server (NTRS)

    Spencer, R. S.; Bergen, G. J.; Fleetwood, C. M.; Herzig, H.; Miner, L.; Rice, S. H.; Smigocki, E.; Woodgate, B. E.; Zaniewski, J. J.

    1985-01-01

    The Solar Maximum Mission (SMM) satellite was launched in February 1980 into a 573 km high circular orbit. It contains X-ray, UV, and optical instruments for the simultaneous observation of solar flares. The ultraviolet spectrometer and polarimeter (UVSP) is one of these instruments. The objectives of the UVSP require the employment of a raster scanning telescope to study the spatial dynamics of flares, the use of a high resolution spectrometer to select and scan spectral lines for temperature and velocity diagnostics, and the utilization of a polarimeter to measure magnetic fields in the solar transition zone. The present paper has the objective to provide a description of the optical fabrication techniques developed for the instrument. Attention is given to telescope mirrors, metering rods, the Ebert mirror, grating blanks, a four-mirror polarizer, beam splitter assemblies, beam splitter fabrication, deflector mirrors, and shipping containers.

  18. A correlation polarimeter for noise-like signals. [optimum estimation of linearly polarized electromagnetic wave

    NASA Technical Reports Server (NTRS)

    Ohlson, J. E.

    1976-01-01

    Optimum estimation (tracking) of the polarization plane of a linearly polarized electromagnetic wave is determined when the signal is a narrow-band Gaussian random process with a polarization plane angle which is also a Gaussian random process. This model is compared to previous work and is applicable to space communication. The estimator performs a correlation operation similar to an amplitude-comparison monopulse angle tracker, giving the name correlation polarimeter. Under large signal-to-noise ratio (SNR), the estimator is causal. Performance of the causal correlation polarimeter is evaluated for arbitrary SNR. Optimum precorrelation filtering is determined. With low SNR, the performance of this system is far better than that of previously developed systems. Practical implementation is discussed. A scheme is given to reduce the effect of linearly polarized noise.

  19. Multi-channel far-infrared HL-2A interferometer-polarimeter.

    PubMed

    Zhou, Y; Deng, Z C; Li, Y G; Yi, J

    2012-10-01

    An HL-2A interferometer is upgraded to a multi-channel interferometer∕polarimeter, which includes four chords for the interferometer and four chords for the polarimeter. The far-infrared lasers (at λ = 432.5 μm and 30 mW power) are used to probe plasmas horizontally in the midplane of HL-2A. A conventional heterodyne technique is used for the interferometer. Two counter-rotating circularly polarized waves are used to measure the Faraday rotation effect. A fast-phase comparator with temporal resolution of 1 μs and phase resolution 0.1° is developed. Further, the distortion of the polarization caused by the beam-splitters and the other optical components is also investigated.

  20. Design and Deployment of a Multichroic Polarimeter Array on the Atacama Cosmology Telescope

    NASA Technical Reports Server (NTRS)

    Datta, R.; Austermann, J.; Beall, J. A.; Becker, D.; Coughlin, K. P.; Duff, S. M.; Gallardo, P.A.; Grace, E.; Hasselfield, M.; Henderson, S. W.; Hilton, G. C.; Ho, S. P.; Hubmayr, J.; Koopman, B. J.; Lanen, J. V.; Li, D.; McMahon, J.; Nati, F.; Munson, C. D.; Niemack, M. D.; Page, L.; Pappas, C. G.; Salatino, M.; Schmitt, B. L.; Wollack, Edward J.

    2016-01-01

    We present the design and the preliminary on-sky performance with respect to beams and pass bands of a multichroic polarimeter array covering the 90 and 146 GHz cosmic microwave background bands and its enabling broad-band optical system recently deployed on the Atacama Cosmology Telescope (ACT). The constituent pixels are feedhorn-coupled multichroic polarimeters fabricated at NIST. This array is coupled to the ACT telescope via a set of three silicon lenses incorporating novel broad-band metamaterial anti-reflection coatings. This receiver represents the first multichroic detector array deployed for a CMB experiment and paves the way for the extensive use of multichroic detectors and broad-band optical systems in the next generation of CMB experiments.

  1. POL-2: a polarimeter for the James-Clerk-Maxwell telescope

    NASA Astrophysics Data System (ADS)

    Friberg, Per; Bastien, Pierre; Berry, David; Savini, Giorgio; Graves, Sarah F.; Pattle, Kate

    2016-07-01

    The POL-2 polarimeter for the SCUBA-2 10 000 pixel Terahertz camera on the James Clerk Maxwell Telescope (JCMT) in it's late state of commissioning. Proposals have been accepted for POL-2 and general observing will start in August 2016. SCUBA-2 has a field of view of 43 arcmin at both of the 850 and 450 μm focal planes. POL-2 will map the sky in the the 850 μm band. The POL-2 polarimeter utilizes three optical components: a half wave plate and two wire-grid polarizers used as calibrator and analyzer covering the full field of SCUBA-2. We describe the instrument, data acquisition and features/artifacts that have been encountered during the commissioning.

  2. Design of the polarimeter for the Solar Activity Measurements Experiments (SAMEX) vector magnetograph

    NASA Technical Reports Server (NTRS)

    West, E. A.; Reichmann, E. J.; Hagyard, M. J.; Gary, G. A.

    1989-01-01

    A design concept developed for a polarimeter on the vector magnetograph of the SAMEX satellite that would be very sensitive to solar vector magnetic fields is described. A description of the Poincare sphere is presented, along with the instrument scientific requirements, to provide an understanding of how the polarimeter design has been selected. It is shown that the design goal of a polarimetric sensitivity of 0.0001 can be achieved in the linear measurements using a hybrid analyzer. It is also noted that the systematic errors that produce linear crosstalk into the circular measurement will require the use of the redundant polarization measurements for in-flight calibrations and corrections of the data.

  3. Solar flare X-ray polarimeter utilizing a large area thin beryllium scattering disk

    NASA Technical Reports Server (NTRS)

    Gotthelf, E.; Hamilton, T.; Novick, R.; Chanan, G.; Emslie, A.; Weisskopf, M.

    1989-01-01

    A model of a solar flare X-ray polarimeter utilizing a large-area thin beryllium scattering disk was developed using Monte Carlo techniques for several classes of solar flares. The solar-flare polarimeter consists of a 30-cm-diam Be disk of about 1/3 of a scattering length thickness, which is surrounded by a cylindrical detector composed of six segmented panels of NaI scintillators, each coupled to 15 photomultiplier tubes. The instrument is sensitive to X-rays from 10 to 100 keV. For a class-M-2 solar flare observed for 10 sec from a balloon at an altitude of 150,000 ft, the minimum detectable polarization at the 99 percent statistical confidence level was found to be 1-6 percent over the energy range 20-100 keV.

  4. Calibration of Passive Microwave Polarimeters that Use Hybrid Coupler-Based Correlators

    NASA Technical Reports Server (NTRS)

    Piepmeier, J. R.

    2003-01-01

    Four calibration algorithms are studied for microwave polarimeters that use hybrid coupler-based correlators: 1) conventional two-look of hot and cold sources, 2) three looks of hot and cold source combinations, 3) two-look with correlated source, and 4) four-look combining methods 2 and 3. The systematic errors are found to depend on the polarimeter component parameters and accuracy of calibration noise temperatures. A case study radiometer in four different remote sensing scenarios was considered in light of these results. Applications for Ocean surface salinity, Ocean surface winds, and soil moisture were found to be sensitive to different systematic errors. Finally, a standard uncertainty analysis was performed on the four-look calibration algorithm, which was found to be most sensitive to the correlated calibration source.

  5. Analysis of Data from the Balloon Borne Gamma RAy Polarimeter Experiment (GRAPE)

    NASA Astrophysics Data System (ADS)

    Wasti, Sambid K.; Bloser, Peter F.; Legere, Jason S.; McConnell, Mark L.; Ryan, James M.

    2016-04-01

    The Gamma Ray Polarimeter Experiment (GRAPE), a balloon borne polarimeter for 50~300 keV gamma rays, successfully flew in 2011 and 2014. The main goal of these balloon flights was to measure the gamma ray polarization of the Crab Nebula. Analysis of data from the first two balloon flights of GRAPE has been challenging due to significant changes in the background level during each flight. We have developed a technique based on the Principle Component Analysis (PCA) to estimate the background for the Crab observation. We found that the background depended mostly on the atmospheric depth, pointing zenith angle and instrument temperatures. Incorporating Anti-coincidence shield data (which served as a surrogate for the background) was also found to improve the analysis. Here, we present the calibration data and describe the analysis done on the GRAPE 2014 flight data.

  6. Design and Deployment of a Multichroic Polarimeter Array on the Atacama Cosmology Telescope

    NASA Astrophysics Data System (ADS)

    Datta, R.; Austermann, J.; Beall, J. A.; Becker, D.; Coughlin, K. P.; Duff, S. M.; Gallardo, P. A.; Grace, E.; Hasselfield, M.; Henderson, S. W.; Hilton, G. C.; Ho, S. P.; Hubmayr, J.; Koopman, B. J.; Lanen, J. V.; Li, D.; McMahon, J.; Munson, C. D.; Nati, F.; Niemack, M. D.; Page, L.; Pappas, C. G.; Salatino, M.; Schmitt, B. L.; Schillaci, A.; Simon, S. M.; Staggs, S. T.; Stevens, J. R.; Vavagiakis, E. M.; Ward, J. T.; Wollack, E. J.

    2016-08-01

    We present the design and the preliminary on-sky performance with respect to beams and passbands of a multichroic polarimeter array covering the 90 and 146 GHz cosmic microwave background bands and its enabling broad-band optical system recently deployed on the Atacama Cosmology Telescope (ACT). The constituent pixels are feedhorn-coupled multichroic polarimeters fabricated at NIST. This array is coupled to the ACT telescope via a set of three silicon lenses incorporating novel broad-band metamaterial anti-reflection coatings. This receiver represents the first multichroic detector array deployed for a CMB experiment and paves the way for the extensive use of multichroic detectors and broad-band optical systems in the next generation of CMB experiments.

  7. Double-wedged Wollaston-type polarimeter design and integration to RTT150-TFOSC

    NASA Astrophysics Data System (ADS)

    Helhel, Selcuk; Kirbiyik, Halil; Bayar, Cevdet; Khamitov, Irek; Kahya, Gizem; Okuyan, Oguzhan

    2016-07-01

    Photometric and spectroscopic observation capabilities of 1.5-m Russian- Turkish Telescope RTT150 has been broadened with the integration of presented polarimeter. The well-known double-wedged Wollaston-type dual-beam technique was preferred and applied to design and produce it. The designed polarimeter was integrated into the telescope detector TFOSC, and called TFOSC-WP. Its capabil- ities and limitations were attempted to be determined by a number of observation sets. Non-polarized and strongly polarized stars were observed to determine its limi- tations as well as its linearity. An instrumental intrinsic polarization was determined for the 1×5 arcmin field of view in equatorial coordinate system, the systematic error of polarization degree as 0.2% %, and position angle as 1.9°. These limitations and capabilities are denoted as good enough to satisfy telescopes' present and future astrophysical space missions related to GAIA and SRG projects.

  8. Aerodynamic Analyses Requiring Advanced Computers, Part 1

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Papers are presented which deal with results of theoretical research on aerodynamic flow problems requiring the use of advanced computers. Topics discussed include: viscous flows, boundary layer equations, turbulence modeling and Navier-Stokes equations, and internal flows.

  9. Compton polarimeter for 10-30 keV x rays

    NASA Astrophysics Data System (ADS)

    Weber, S.; Beilmann, C.; Shah, C.; Tashenov, S.

    2015-09-01

    We present a simple and versatile polarimeter for x rays in the energy range of 10-30 keV. It uses Compton scattering in low-Z materials such as beryllium or boron carbide. The azimuthal distribution of the scattered x rays is sampled by an array of 12 silicon PIN diodes operated at room temperature. We evaluated the polarimetry performance using Monte-Carlo simulations and show experimental results.

  10. The Cosmology Large Angular Scale Surveyor (CLASS): 38 GHz Detector Array of Bolometric Polarimeters

    NASA Technical Reports Server (NTRS)

    Appel, John W.; Ali, Aamir; Amiri, Mandana; Araujo, Derek; Bennett, Charles L.; Boone, Fletcher; Chan, Manwei; Cho, Hsiao-Mei; Chuss, David T.; Colazo, Felipe; Crowe, Erik; Denis, Kevin; Dunner, Rolando; Eimer, Joseph; Essinger-Hileman, Thomas; Gothe, Dominik; Halpern, Mark; Harrington, Kathleen; Kogut, Alan J..; Miller, Nathan; Moseley, Samuel H.; Stevenson, Thomas; Towner, Deborah; U-Yen, Kongpop; Wollack, Edward

    2014-01-01

    The Cosmology Large Angular Scale Surveyor (CLASS) experiment aims to map the polarization of the Cosmic Microwave Background (CMB) at angular scales larger than a few degrees. Operating from Cerro Toco in the Atacama Desert of Chile, it will observe over 65% of the sky at 38, 93, 148, and 217 GHz. In this paper we discuss the design, construction, and characterization of the CLASS 38 GHz detector focal plane, the first ever Q-band bolometric polarimeter array.

  11. A digital panoramic polarimeter for study of space debris and near Earth asteroids

    NASA Astrophysics Data System (ADS)

    Vidmachenko, A. P.; Delets, A. S.; Nevodovskiy, P. V.; Andruk, V. M.

    2003-12-01

    Meteorites, asteroids, and other space object (natural and artificial debris), moving in the vicinity of the Earth orbit, are very dangerous both for life on the Earth, and the Earth existence. Polarimetric method for study of near Earth asteroid and space debris is very efficient for their registrations on the background of the sky, the determination their optical and physical parameters. In MAO of NASU is has been created a polarimetric complex "Digital polarimeter", capable to execute these problems.

  12. The low Q$^2$ chicane and Compton polarimeter at the JLab EIC

    SciTech Connect

    Camsonne, Alexandre

    2016-03-01

    The JLAB EIC (JLEIC) design includes a chicane after the interaction point to detect electron associated with production of quasi-real photon at the interaction. This chicane layout can also be used for Compton polarimetry to measure the electron beam polarization. This proceeding will present the layout of the low Q^2 chicane and the implementation and current R&D; of a Compton polarimeter which would be located in the middle of this chicane.

  13. Compton polarimeter for 10–30 keV x rays

    SciTech Connect

    Weber, S.; Beilmann, C.; Shah, C.; Tashenov, S.

    2015-09-15

    We present a simple and versatile polarimeter for x rays in the energy range of 10–30 keV. It uses Compton scattering in low-Z materials such as beryllium or boron carbide. The azimuthal distribution of the scattered x rays is sampled by an array of 12 silicon PIN diodes operated at room temperature. We evaluated the polarimetry performance using Monte-Carlo simulations and show experimental results.

  14. Waveform dependence on signal amplitude in the RHIC H-Jet polarimeter

    SciTech Connect

    Poblaguev, A. A.

    2014-02-25

    A simulation of the signal waveform in the H-Jet polarimeter is discussed. The simulation includes a model of charge collection in the silicon detector and a response functions of the H-Jet front end electronics. Results of the simulation are compared with experimental data. It is shown that an analysis of the signal shape may help to suppress background in the H-Jet polarization measurements.

  15. Data acquisition system of Moeller polarimeter Hall A Jefferson Lab (in Russian)

    SciTech Connect

    Roman Pomatsalyuk

    2012-11-01

    The structure, parameters and test results of a new data acquisition system for Moller polarimeter based on flash-ADC are presented. Flash-ADC is electronic module in VME format that consists of high-speed multichannel ADC piped type and FPGA unit on board. The use of flash-ADC has a lot of advantages: reduce of cable interconnections, events registration with higher rate, considerable decreases of system deadtime and, as result, the accuracy of polarization measurements is increases.

  16. Recent Progress of the HL-2A Multi-Channel HCOOH Laser Interferometer/Polarimeter

    NASA Astrophysics Data System (ADS)

    Li, Yonggao; Zhou, Yan; Deng, Zhongchao; Li, Yuan; Yi, Jiang; Wang, Haoxi

    2015-05-01

    A multichannel methanoic acid (HCOOH, λ = 432.5 μm) laser interferometer/polarimeter is being developed from the previous eight-channel hydrogen cyanide (HCN, λ = 337 μm) laser interferometer in the HL-2A tokamak. A conventional Michelson-type interometer is used for the electron density measurement, and a Dodel-Kunz-type polarimeter is used for the Faraday rotation effect measurement, respectively. Each HCOOH laser can produce a linearly polarized radiation at a power lever of ˜30 mW, and a power stability <10% in 50 min. A beam waist (diameter d0 ≈12.0 mm, about 200 mm away from the outlet) is finally determined through a chopping modulation technique. The latest optical layout of the interferometer/polarimeter has been finished, and the hardware data processing system based on the fast Fourier transform phase-comparator technique is being explored. In order to demonstrate the feasibility of the diagnostic scheme, two associated bench simulation experiments were carried out in the laboratory, in which the plasma was simulated by a piece of polytetrafluoroethene plate, and the Faraday rotation effect was simulated by a rotating half-wave plate. Simulation results agreed well with the initial experimental conditions. At present, the HCOOH laser interferometer/polarimeter system is being assembled on HL-2A, and is planned to be applied in the 2014-2015 experimental campaign. supported by the National Magnetic Confinement Fusion Science Programs of China (Nos. 2010GB101002 and 2014GB109001), and National Natural Science Foundation of China (Nos. 11075048 and 11275059)

  17. Polarimeter with linear response for measuring optical activity in organic compounds

    NASA Astrophysics Data System (ADS)

    Flores, Jorge L.; Montoya, Marcial; Garcia-Torales, G.; Gonzalez Alvarez, Alejandro

    2005-08-01

    A polarimeter designed for measuring small rotation angles on the polarization plane of light is described. The experimental device employs one fixed polarizer and a rotating analyzer. The system generates a periodical intensity signal, which is then Fourier analyzed. The coefficients of Fourier Transform contain information about rotation angles produced by organic compounds that exhibited optical activity. The experimental device can be used to determine the sugar concentration in agave juice.

  18. A multiple-scale Pascal polynomial for 2D Stokes and inverse Cauchy-Stokes problems

    NASA Astrophysics Data System (ADS)

    Liu, Chein-Shan; Young, D. L.

    2016-05-01

    The polynomial expansion method is a useful tool for solving both the direct and inverse Stokes problems, which together with the pointwise collocation technique is easy to derive the algebraic equations for satisfying the Stokes differential equations and the specified boundary conditions. In this paper we propose two novel numerical algorithms, based on a third-first order system and a third-third order system, to solve the direct and the inverse Cauchy problems in Stokes flows by developing a multiple-scale Pascal polynomial method, of which the scales are determined a priori by the collocation points. To assess the performance through numerical experiments, we find that the multiple-scale Pascal polynomial expansion method (MSPEM) is accurate and stable against large noise.

  19. Development of a Hydrogen Møller Polarimeter for Precision Parity-Violating Electron Scattering

    NASA Astrophysics Data System (ADS)

    Gray, Valerie M.

    2013-10-01

    Parity-violating electron scattering experiments allow for testing the Standard Model at low energy accelerators. Future parity-violating electron scattering experiments, like the P2 experiment at the Johannes Gutenberg University, Mainz, Germany, and the MOLLER and SoLID experiments at Jefferson Lab will measure observables predicted by the Standard Model to high precision. In order to make these measurements, we will need to determine the polarization of the electron beam to sub-percent precision. The present way of measuring the polarization, with Møller scattering in iron foils or using Compton laser backscattering, will not easily be able to reach this precision. The novel Hydrogen Møller Polarimeter presents a non-invasive way to measure the electron polarization by scattering the electron beam off of atomic hydrogen gas polarized in a 7 Tesla solenoidal magnetic trap. This apparatus is expected to be operational by 2016 in Mainz. Currently, simulations of the polarimeter are used to develop the detection system at College of William & Mary, while the hydrogen trap and superconducting solenoid magnet are being developed at the Johannes Gutenberg University, Mainz. I will discuss the progress of the design and development of this novel polarimeter system. This material is based upon work supported by the National Science Foundation under Grant No. PHY-1206053.

  20. Investigating the circumstellar environments of young stars with the PROMPT polarimeter

    NASA Astrophysics Data System (ADS)

    Moran, Jane A.

    We have designed and built a prototype imaging polarimeter for use on the PROMPT robotic telescopes located at the Cerro Tololo International Observatory. The polarimeter uses a Fresnel rhomb and wollaston prism to image two orthogonal polarization states onto a single CCD chip, with an image field of view of 10x4.5 arcmin. Using the polarimeter, we have investigated the circumstellar regions of 11 Herbig Ae/Be stars, and done extensive follow-up observations of 3 stars of interest: KK Oph, a well-studied star with previously limited polarimetric data; NX Pup, a star known to vary photometrically but with previously unknown polarimetric variability; and SS7344, a star with very limited previous photometric data and no prior polarimetric data. We have found polarimetric and photometric variations in KK Oph and NX Pup that are consistent with models of dust obscuration. Both KK Oph and NX Pup show an increase in polarization accompanied by a decrease in visual magnitude and a reddening. However, neither star shows the "blueing" at deep minima and maximum polarization characteristic of the UXor classification of stars. We have demonstrated that SS7344 has an intrinsic polarization, but does not display the photometric and polarimetric variations expected from a young star with an evolving circumstellar environment, indicating that this object either has a disk seen in an orientation that has little inclination, or one with no appreciable puffed-up inner rim.

  1. Silicon photomultipliers as readout elements for a Compton effect polarimeter: the COMPASS project

    NASA Astrophysics Data System (ADS)

    Del Monte, E.; Rubini, A.; Brandonisio, A.; Muleri, F.; Soffitta, P.; Costa, E.; Di Persio, G.; Di Cosimo, S.; Massaro, E.; Morbidini, A.; Morelli, E.; Pacciani, L.; Fabiani, S.; Michilli, D.; Giarrusso, S.; Catalano, O.; Impiombato, D.; Mineo, T.; Sottile, G.; Billotta, S.

    2016-08-01

    COMpton Polarimeter with Avalanche Silicon readout (COMPASS) is a research and development project that aims to measure the polarization of X-ray photons through Compton Scattering. The measurement is obtained by using a set of small rods of fast scintillation materials with both low-Z (as active scatterer) and high-Z (as absorber), all read-out with Silicon Photomultipliers. By this method we can operate scattering and absorbing elements in coincidence, in order to reduce the background. In the laboratory we are characterising the SiPMs using different types of scintillators and we are optimising the performances in terms of energy resolution, energy threshold and photon tagging efficiency. We aim to study the design of two types of satellite-borne instruments: a focal plane polarimeter to be coupled with multilayer optics for hard X-rays and a large area and wide field of view polarimeter for transients and Gamma Ray Bursts. In this paper we describe the status of the COMPASS project, we report about the laboratory measurements and we describe our future perspectives.

  2. First results from the J-TEXT high-resolution three-wave polarimeter-interferometer.

    PubMed

    Chen, J; Zhuang, G; Wang, Z J; Gao, L; Li, Q; Chen, W; Brower, D L; Ding, W X

    2012-10-01

    A laser-based far-infrared polarimeter-interferometer system utilizing the three-wave technique has been implemented on the J-TEXT tokamak. The polarimeter determines the Faraday effect by measuring the phase difference between two collinear, counter-rotating, circularly polarized laser beams. The first results of the polarimeter-interferometer designed for J-TEXT have been obtained in the most recent J-TEXT experimental campaign. Simultaneous polarimetric and interferometric measurement is achieved, with phase resolution up to 0.1°, at bandwidth of 50 kHz. The temporal resolution, which is dependent on the laser's frequency offset, is ∼1 μs. Continual spatial measurement covering 45 cm (80% of the plasma cross-section) is realized by utilizing 1D parabolic beam expansion optics. Three initial test chords are installed and future plans call for expansion up to 30 chords with 1.5 cm chord spacing, providing high spatial resolution for measurement of electron density and current density profiles. Reliability of both polarimetric and interferometric measurement is confirmed by comparison with computation and data from a hydrocyanic acid (HCN) interferometer. With the high temporal and phase resolution, perturbations associated with the sawtooth cycle and MHD activity have been observed.

  3. First results from the J-TEXT high-resolution three-wave polarimeter-interferometera)

    NASA Astrophysics Data System (ADS)

    Chen, J.; Zhuang, G.; Wang, Z. J.; Gao, L.; Li, Q.; Chen, W.; Brower, D. L.; Ding, W. X.

    2012-10-01

    A laser-based far-infrared polarimeter-interferometer system utilizing the three-wave technique has been implemented on the J-TEXT tokamak. The polarimeter determines the Faraday effect by measuring the phase difference between two collinear, counter-rotating, circularly polarized laser beams. The first results of the polarimeter-interferometer designed for J-TEXT have been obtained in the most recent J-TEXT experimental campaign. Simultaneous polarimetric and interferometric measurement is achieved, with phase resolution up to 0.1°, at bandwidth of 50 kHz. The temporal resolution, which is dependent on the laser's frequency offset, is ˜1 μs. Continual spatial measurement covering 45 cm (80% of the plasma cross-section) is realized by utilizing 1D parabolic beam expansion optics. Three initial test chords are installed and future plans call for expansion up to 30 chords with 1.5 cm chord spacing, providing high spatial resolution for measurement of electron density and current density profiles. Reliability of both polarimetric and interferometric measurement is confirmed by comparison with computation and data from a hydrocyanic acid (HCN) interferometer. With the high temporal and phase resolution, perturbations associated with the sawtooth cycle and MHD activity have been observed.

  4. First results from the J-TEXT high-resolution three-wave polarimeter-interferometer

    SciTech Connect

    Chen, J.; Zhuang, G.; Wang, Z. J.; Gao, L.; Li, Q.; Chen, W.; Brower, D. L.; Ding, W. X.

    2012-10-15

    A laser-based far-infrared polarimeter-interferometer system utilizing the three-wave technique has been implemented on the J-TEXT tokamak. The polarimeter determines the Faraday effect by measuring the phase difference between two collinear, counter-rotating, circularly polarized laser beams. The first results of the polarimeter-interferometer designed for J-TEXT have been obtained in the most recent J-TEXT experimental campaign. Simultaneous polarimetric and interferometric measurement is achieved, with phase resolution up to 0.1 Degree-Sign , at bandwidth of 50 kHz. The temporal resolution, which is dependent on the laser's frequency offset, is {approx}1 {mu}s. Continual spatial measurement covering 45 cm (80% of the plasma cross-section) is realized by utilizing 1D parabolic beam expansion optics. Three initial test chords are installed and future plans call for expansion up to 30 chords with 1.5 cm chord spacing, providing high spatial resolution for measurement of electron density and current density profiles. Reliability of both polarimetric and interferometric measurement is confirmed by comparison with computation and data from a hydrocyanic acid (HCN) interferometer. With the high temporal and phase resolution, perturbations associated with the sawtooth cycle and MHD activity have been observed.

  5. Understanding Stokes forces in the wave-averaged equations

    NASA Astrophysics Data System (ADS)

    Suzuki, Nobuhiro; Fox-Kemper, Baylor

    2016-05-01

    The wave-averaged, or Craik-Leibovich, equations describe the dynamics of upper ocean flow interacting with nonbreaking, not steep, surface gravity waves. This paper formulates the wave effects in these equations in terms of three contributions to momentum: Stokes advection, Stokes Coriolis force, and Stokes shear force. Each contribution scales with a distinctive parameter. Moreover, these contributions affect the turbulence energetics differently from each other such that the classification of instabilities is possible accordingly. Stokes advection transfers energy between turbulence and Eulerian mean-flow kinetic energy, and its form also parallels the advection of tracers such as salinity, buoyancy, and potential vorticity. Stokes shear force transfers energy between turbulence and surface waves. The Stokes Coriolis force can also transfer energy between turbulence and waves, but this occurs only if the Stokes drift fluctuates. Furthermore, this formulation elucidates the unique nature of Stokes shear force and also allows direct comparison of Stokes shear force with buoyancy. As a result, the classic Langmuir instabilities of Craik and Leibovich, wave-balanced fronts and filaments, Stokes perturbations of symmetric and geostrophic instabilities, the wavy Ekman layer, and the wavy hydrostatic balance are framed in terms of intuitive physical balances.

  6. Incompressible Navier-Stokes and parabolized Navier-Stokes formulations and computational techniques

    NASA Technical Reports Server (NTRS)

    Rubin, S. G.

    1984-01-01

    The differential formulations and computational techniques currently used for the incompressible Navier-Stokes (NS) and parabolic Navier-Stokes (PNS) equations are reviewed. In particular, attention is given to problems associated with the choice of difference equations, the method of solution and the choice of algorithm, the coupling of dependent variables and discretized equations, the application of boundary conditions, and grid generation. A new composite velocity NS and PNS formulation in (u,v,p) variables is presented, and the applicability of a 'forward' difference global pressure iteration for the (u,v,p) PNS system is demonstrated.

  7. Adrian Stokes and the portrait of Melanie Klein.

    PubMed

    Sayers, Janet

    2015-08-01

    This paper focuses on the offer by the art writer Adrian Stokes to commission and pay for a portrait of the psychoanalyst Melanie Klein by the artist William Coldstream. It details some of the precursors of this offer in Stokes's preceding involvement first with Klein and then with Coldstream; her response to this offer; and its outcome and aftermath in Stokes's subsequent writing about Klein and Coldstream.

  8. Gravitational Stokes parameters. [for electromagnetic and gravitational radiation in relativity

    NASA Technical Reports Server (NTRS)

    Anile, A. M.; Breuer, R. A.

    1974-01-01

    The electromagnetic and gravitational Stokes parameters are defined in the general theory of relativity. The general-relativistic equation of radiative transfer for polarized radiation is then derived in terms of the Stokes parameters for both high-frequency electromagnetic and gravitational waves. The concept of Stokes parameters is generalized for the most general class of metric theories of gravity, where six (instead of two) independent states of polarization are present.

  9. Parallelization of Unsteady Adaptive Mesh Refinement for Unstructured Navier-Stokes Solvers

    NASA Technical Reports Server (NTRS)

    Schwing, Alan M.; Nompelis, Ioannis; Candler, Graham V.

    2014-01-01

    This paper explores the implementation of the MPI parallelization in a Navier-Stokes solver using adaptive mesh re nement. Viscous and inviscid test problems are considered for the purpose of benchmarking, as are implicit and explicit time advancement methods. The main test problem for comparison includes e ects from boundary layers and other viscous features and requires a large number of grid points for accurate computation. Ex- perimental validation against double cone experiments in hypersonic ow are shown. The adaptive mesh re nement shows promise for a staple test problem in the hypersonic com- munity. Extension to more advanced techniques for more complicated ows is described.

  10. On the Doppler Shift and Asymmetry of Stokes Profiles of Photospheric FeI and Chromospheric MgI Lines

    DTIC Science & Technology

    2010-06-15

    10/09 ON THE DOPPLER SHIFT AND ASYMMETRY OF STOKES PROFILES OF PHOTOSPHERIC Fe I AND CHROMOSPHERIC Mg I LINES NA DENG AND DEBI PRASAD CHOUDHARY...photospheric (Fe I 630.15 and 630.25 nm) and chromospheric (Mg I b2 517.27 nm) lines. The data were obtained with the HAO/NSO Advanced Stokes...among the three spectral lines, which helps us to better understand the chromospheric lines and the magnetic and flow fields in different magnetic

  11. Historical revision of the differential Stokes-Mueller formalism: discussion.

    PubMed

    Arteaga, Oriol

    2017-03-01

    The differential Stokes-Mueller matrix formalism expresses the local evolution of the Mueller matrix or the Stokes parameters for light propagating through a homogeneous optical medium. This paper presents a historical revision of the development of the differential Stokes-Mueller matrix formalism and highlights several important early contributions that have been overlooked. Particularly relevant is that this formalism was pioneered as early as 1929 by Paul Soleillet, almost 50 years earlier than it has been usually assumed. This historical revision demonstrates that several different authors independently formulated the differential Stokes-Mueller formalism during the 20th century and they found equivalent results studying the propagation problem from different approaches.

  12. Fast solvers for finite difference approximations for the Stokes and Navier-Stokes equations

    SciTech Connect

    Shin, D.

    1992-01-01

    The authors consider several methods for solving the linear equations arising from finite difference discretizations of the Stokes equations. The pressure equation method presented here for the first time, apparently, and the method, presented by Bramble and Pasciak, are shown to have computational effort that grows slowly with the number of grid points. The methods work with second-order accurate discretizations. Computational results are shown for both the Stokes and incompressible Navier-Stokes at low Reynolds number. The inf-sup conditions resulting from three finite difference approximations of the Stokes equations are proven. These conditions are used to prove that the Schur complement Q[sub h] of the linear system generated by each of these approximations is bounded uniformly away from zero. For the pressure equation method, this guarantees that the conjugate gradient method applied to Q[sub h] converges in a finite number of iterations which is independent of mesh size. The fact that Q[sub h] is bounded below is used to prove convergence estimates for the solutions generated by these finite difference approximations. One of the estimates is for a staggered grid and the estimate of the scheme shows that both the pressure and the velocity parts of the solution are second-order accurate. Iterative methods are compared by the use of the regularized central differencing introduced by Strikwerda. Several finite difference approximations of the Stokes equations by the SOR method are compared and the excellence of the approximations by the regularized central differencing over the other finite difference approximation is mentioned. This difference gives rise to a linear equation with a matrix which is slightly non-symmetric. The convergence of the typical steepest descent method and conjugate gradient method, which is almost as same as the typical conjugate gradient method, applied to slightly non-symmetric positive definite matrices are proven.

  13. Stokes problems for moving half-planes.

    PubMed

    Zeng, Y; Weinbaum, S

    1995-01-01

    New exact solutions of the Navier-Stokes equations are obtained for the unbounded and bounded oscillatory and impulsive tangential edgewise motion of touching half-infinite plates in their own plane. In contrast to Stokes classical solutions for the harmonic and impulsive motion of an infinite plane wall, where the solutions are separable or have a simple similarity form, the present solutions have a two-dimensional structure in the near region of the contact between the half-infinite plates. Nevertheless, it is possible to obtain relatively simple closed-form solutions for the flow field in each case by defining new variables which greatly simplify the r- and theta- dependence of the solutions in the vicinity of the contact region. These solutions for flow in a half-infinite space are then extended to bounded flows in a channel using an image superposition technique. The impulsive motion has application to the motion near geophysical faults, whereas the oscillatory motion has arisen in the design of a novel oscillating half-plate flow chamber for examining the effect of fluid shear stress on cultured cell monolayers.

  14. Pseudospectral Algorithms for Navier-Stokes Simulation of Turbulent Flows in Cylindrical Geometry with Coordinate Singularities

    NASA Astrophysics Data System (ADS)

    Priymak, V. G.

    1995-05-01

    We present a new family of algorithms for incompressible 3D Navier-Stokes equations in cylindrical geometry. A model problem of turbulent flow calculation in an infinite circular pipe {(r, ϕ, z): 0 ≤ r ≤ R, 0 ≤ ϕ < 2π, |z| < ∞} is considered and used for accuracy, stability, and efficiency estimations. Algorithms are based on Galerkin trigonometric approximation for uniform variables ϕ, z, on pseudospectral polynomial approximation in the r -direction (with different sets of collocation nodes) and on implicit and predictor-corrector time advancement schemes. In all cases high (infinite order) spatial accuracy is retained despite the presence of coordinate singularity at r = 0. To achieve this we exploit the behaviour of analytic functions of variables r, ϕ, z in the vicinity of r = 0. We analyze the advantages and disadvantages of four Navier-Stokes algorithms. In method A a new splitting technique is developed which makes use of a second-order predictor-corrector scheme and nontraditional fractional step procedure. Stability and efficiency characteristics of this scheme exceed that of the usually used mixed Adams-Bashforth/Crank-Nicolson time advancement. To minimize errors due to splitting, algorithm B is suggested that has no fractional steps. In this method pressure values are eliminated from discretized Navier-Stokes equations by means of equivalent matrix operations. Although conventional Chebyshev collocation nodes rl = R cos(πl/2Q), l = 0, 1, ..., Q, are used in both methods, the discrete boundary conditions at r = 0-consistent with analytic behaviour of solutions for small r-are fully accessible for the first time. In addition, approximations developed prevent the appearance of various pathological (with, e.g., spurious, parasitic modes, etc.) discretizations of Navier-Stokes operators. In algorithm C we propose a new set of collocation nodes rl = (1 - xl)R/2, l = 0, 1, ..., Q, where xl ɛ (-1, 1), l = 1, 2, ..., Q - 1, are the zeros of

  15. Performance Characterization of UV Science Cameras Developed for the Chromospheric Lyman-Alpha Spectro-Polarimeter

    NASA Technical Reports Server (NTRS)

    Champey, Patrick; Kobayashi, Ken; Winebarger, Amy; Cirtain, Jonathan; Hyde, David; Robertson, Bryan; Beabout, Brent; Beabout, Dyana; Stewart, Mike

    2014-01-01

    The NASA Marshall Space Flight Center (MSFC) has developed a science camera suitable for sub-orbital missions for observations in the UV, EUV and soft X-ray. Six cameras will be built and tested for flight with the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP), a joint National Astronomical Observatory of Japan (NAOJ) and MSFC sounding rocket mission. The goal of the CLASP mission is to observe the scattering polarization in Lyman-alpha and to detect the Hanle effect in the line core. Due to the nature of Lyman-alpha polarization in the chromosphere, strict measurement sensitivity requirements are imposed on the CLASP polarimeter and spectrograph systems; science requirements for polarization measurements of Q/I and U/I are 0.1 percent in the line core. CLASP is a dual-beam spectro- polarimeter, which uses a continuously rotating waveplate as a polarization modulator, while the waveplate motor driver outputs trigger pulses to synchronize the exposures. The CCDs are operated in frame-transfer mode; the trigger pulse initiates the frame transfer, effectively ending the ongoing exposure and starting the next. The strict requirement of 0.1 percent polarization accuracy is met by using frame-transfer cameras to maximize the duty cycle in order to minimize photon noise. Coating the e2v CCD57-10 512x512 detectors with Lumogen-E coating allows for a relatively high (30 percent) quantum efficiency at the Lyman-alpha line. The CLASP cameras were designed to operate with a gain of 2.0 +/- 0.5, less than or equal to 25 e- readout noise, less than or equal to 10 e-/second/pixel dark current, and less than 0.1percent residual non-linearity. We present the results of the performance characterization study performed on the CLASP prototype camera; system gain, dark current, read noise, and residual non-linearity.

  16. Performance Characterization of UV Science Cameras Developed for the Chromospheric Lyman-Alpha Spectro-Polarimeter

    NASA Technical Reports Server (NTRS)

    Champey, P.; Kobayashi, K.; Winebarger, A.; Cirtain, J.; Hyde, D.; Robertson, B.; Beabout, D.; Beabout, B.; Stewart, M.

    2014-01-01

    The NASA Marshall Space Flight Center (MSFC) has developed a science camera suitable for sub-orbital missions for observations in the UV, EUV and soft X-ray. Six cameras will be built and tested for flight with the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP), a joint National Astronomical Observatory of Japan (NAOJ) and MSFC sounding rocket mission. The goal of the CLASP mission is to observe the scattering polarization in Lyman-alpha and to detect the Hanle effect in the line core. Due to the nature of Lyman-alpha polarization in the chromosphere, strict measurement sensitivity requirements are imposed on the CLASP polarimeter and spectrograph systems; science requirements for polarization measurements of Q/I and U/I are 0.1 percent in the line core. CLASP is a dual-beam spectro-polarimeter, which uses a continuously rotating waveplate as a polarization modulator, while the waveplate motor driver outputs trigger pulses to synchronize the exposures. The CCDs are operated in frame-transfer mode; the trigger pulse initiates the frame transfer, effectively ending the ongoing exposure and starting the next. The strict requirement of 0.1 percent polarization accuracy is met by using frame-transfer cameras to maximize the duty cycle in order to minimize photon noise. Coating the e2v CCD57-10 512x512 detectors with Lumogen-E coating allows for a relatively high (30 percent) quantum efficiency at the Lyman-alpha line. The CLASP cameras were designed to operate with 10 e-/pixel/second dark current, 25 e- read noise, a gain of 2.0 +/- 0.5 and 1.0 percent residual non-linearity. We present the results of the performance characterization study performed on the CLASP prototype camera; dark current, read noise, camera gain and residual non-linearity.

  17. A High-Precision, Optical Polarimeter to Measure Inclinations of High Mass X-Ray Binaries

    NASA Astrophysics Data System (ADS)

    Wiktorowicz, Sloane; Matthews, K.; Kulkarni, S. R.

    2007-12-01

    While most astrophysical objects require many parameters in order to be fully described, black holes are unique in that only three parameters are required: mass, spin, and charge. Of these, mass and spin are enough to describe the black hole's gravitational field and event horizon location. Therefore, theory and observation may jointly pursue one or two quantities to uncover the progenitor star's history. Constraints on black hole mass exist for high mass X-ray binaries, such as Cygnus X-1, which is thought to consist of a 40 ± 10 solar mass O9.7Iab star and a 13.5-29 solar mass black hole (Ziolkowski 2005). While the constraints on the mass of the compact object are tight enough to declare that it is a black hole, they are sufficiently loose as to prohibit precise modeling of the progenitor star's mass. We have built an optical polarimeter for the Hale 5-m telescope at Mt. Palomar to provide an independent method for determining black hole mass. Degree of polarization will vary for an edge-on system, while position angle of net polarization will vary for a face-on system. Therefore, by monitoring the linear polarimetric variability of the binary, inclination can be estimated. Coupled with the known mass function of the binary from radial velocity work (Gies et al. 2003), inclination estimates constrain the mass of the black hole. Our polarimeter, POLISH (POLarimeter for Inclination Studies of High mass x-ray binaries), has achieved linear polarimetric precision of less than 10 parts per million on bright, unpolarized standard stars. We will also present results for polarized standard stars and Cygnus X-1 itself. This instrument has been funded by an endowment from the Moore Foundation.

  18. On the operation of X-ray polarimeters with a large field of view

    SciTech Connect

    Muleri, Fabio

    2014-02-10

    The measurement of linear polarization is one of the hot topics of high-energy astrophysics. Gas detectors based on the photoelectric effect have paved the way for the design of sensitive instruments, and mission proposals based on them have been presented in the last few years in the energy range from about 2 keV to a few tens of keV. In addition, a number of polarimeters based on Compton scattering are approved or being discussed for launch on board balloons or space satellites at higher energies. These instruments are typically dedicated to pointed observations with narrow field of view telescopes or collimators, but there are also projects aimed at the polarimetry of bright transient sources such as soft gamma repeaters or the prompt emission of gamma-ray bursts. Given the erratic appearance of such events in the sky, these polarimeters have large fields of view to catch a reasonable number of them, and as a result, photons may impinge on the detector off-axis. This dramatically changes the response of the instrument to polarization, regardless of whether photoabsorption or Compton scattering is involved. Instead of the simple cosine-squared dependence expected for polarized photons that are incident on-axis, the response is never purely cosinusoidal, and a systematic modulation also appears for unpolarized radiation. We investigate the origin of these differences and present an analytical treatment that proves that such systematic effects are actually a natural consequence of how current instruments operate. Our analysis provides the expected response of photoelectric or Compton polarimeters to photons impinging with any inclination and state of polarization.

  19. General Squirming Motion in a Stokes Flow

    NASA Astrophysics Data System (ADS)

    Pak, On Shun; Lauga, Eric

    2013-11-01

    Some microorganisms such as ciliates (Opalina) and colonies of flagellates (Volvox) are approximately spherical in shape and swim using beating arrays of cilia covering their surfaces. The ciliary motion over the surface may be mathematically modeled as the generation of effectively tangential velocities on the spherical surface - known as squirming motion. Previous analyses assumed axisymmetry and hence restricted all swimming kinematics to take place along a line. Here we remove this limitation and extend the analysis to general non-axisymmetric squirming motion. We derive analytically the three-dimensional translational and rotational swimming velocities as well as the surrounding flow field of a general squirmer. The framework developed here completes the analysis of squirming motion in a Stokes flow.

  20. Stokes paradox in electronic Fermi liquids

    NASA Astrophysics Data System (ADS)

    Lucas, Andrew

    2017-03-01

    The Stokes paradox is the statement that in a viscous two-dimensional fluid, the "linear response" problem of fluid flow around an obstacle is ill posed. We present a simple consequence of this paradox in the hydrodynamic regime of a Fermi liquid of electrons in two-dimensional metals. Using hydrodynamics and kinetic theory, we estimate the contribution of a single cylindrical obstacle to the global electrical resistance of a material, within linear response. Momentum relaxation, present in any realistic electron liquid, resolves the classical paradox. Nonetheless, this paradox imprints itself in the resistance, which can be parametrically larger than predicted by Ohmic transport theory. We find a remarkably rich set of behaviors, depending on whether or not the quasiparticle dynamics in the Fermi liquid should be treated as diffusive, hydrodynamic, or ballistic on the length scale of the obstacle. We argue that all three types of behavior are observable in present day experiments.

  1. Stokes shift spectroscopy for breast cancer diagnosis

    NASA Astrophysics Data System (ADS)

    Jeyasingh, Ebenezar; Prakashrao, Aruna; Singaravelu, Ganesan

    2010-02-01

    The objective of this study is to assess the diagnostic potential of stokes shift (SS) spectroscopy (SSS) for normal and different pathological breast tissues such as fibroadenoma and infiltrating ductal carcinoma. The SS spectra is measured by simultaneously scanning both the excitation and emission wavelengths while keeping a fixed wavelength interval Δλ=20 nm between them. Characteristic, highly resolved peaks and significant spectral differences between normal and different pathological breast tissues were observed. The SS spectra of normal and different pathological breast tissues shows the distinct peaks around 300, 350, 450, 500 and 600 nm may be attributed to tryptophan, collagen, NADH, flavin and porphyrin respectively. Using SSS technique one can obtain all the key fluorophores in a single scan and hence they can be targeted as a tumor markers in this study. In order to quantify the altered spectral differences between normal and different pathological breast tissues are verified by different ratio parameters.

  2. About the Stokes decomposition theorem of waves

    NASA Astrophysics Data System (ADS)

    Lacaze, B.

    2011-06-01

    The Stokes decomposition theorem deals with the electrical field E→=X,Y of a light beam. The theorem asserts that a beam can be viewed as the sum of two differently polarized parts. This result was recently discussed for light in the frame of the unified theory of coherence. We study the general case of an electromagnetic wave which can be in radio, radar, communications, or light. We assume stationary components with any power spectrum and finite or infinite bandwidth. We show that an accurate definition of polarization and unpolarization is a key parameter which rules the set of solutions of the problem. When dealing with a "strong definition" of unpolarization, the problem is treated in the frame of stationary processes and linear invariant filters. When dealing with a "weak definition", solutions are given by elementary properties of bidimensional random variables.

  3. The Proteus Navier-Stokes code

    NASA Technical Reports Server (NTRS)

    Towne, Charles E.; Bui, Trong T.; Cavicchi, Richard H.; Conley, Julianne M.; Molls, Frank B.; Schwab, John R.

    1992-01-01

    An effort is currently underway at NASA Lewis to develop two- and three-dimensional Navier-Stokes codes, called Proteus, for aerospace propulsion applications. The emphasis in the development of Proteus is not algorithm development or research on numerical methods, but rather the development of the code itself. The objective is to develop codes that are user-oriented, easily-modified, and well-documented. Well-proven, state-of-the-art solution algorithms are being used. Code readability, documentation (both internal and external), and validation are being emphasized. This paper is a status report on the Proteus development effort. The analysis and solution procedure are described briefly, and the various features in the code are summarized. The results from some of the validation cases that have been run are presented for both the two- and three-dimensional codes.

  4. Aquarius Third Stokes Parameter Measurements: Initial Results

    NASA Technical Reports Server (NTRS)

    Utku, Cuneyt; Vine, David M Le; Abraham, S.; Piepmeier, J.

    2012-01-01

    The Aquarius/SAC-D observatory was launched on June 10, 2011 and the Aquarius instrument has been collecting data continuously since late August. One of the unique features of the L-band radiometers comprising Aquarius is the presence of a polarimetric channel to measure the third Stokes parameter. The purpose is to provide a measure of Faraday rotation, which can be important for remote sensing at L-band, especially in the case of remote sensing of salinity which requires high precision. Initial results are presented here showing a reasonable agreement between retrieved and modeled Faraday rotation and also the "noisy" behavior at land-water boundaries and other mixed scenes predicted by theory.

  5. Upgraded photon calorimeter with integrating readout for Hall A Compton Polarimeter at Jefferson Lab

    SciTech Connect

    Friend, M.; Parno, D.; Benmokhtar, F.; Camsonne, A.; Dalton, M. M.; Franklin, G. B.; Mamyan, V.; Michaels, R.; Nanda, S.; Nelyubin, V.; Paschke, K.; Quinn, B.; Rakhman, A.; Souder, P.; Tobias, A.

    2012-06-01

    The photon arm of the Compton polarimeter in Hall A of Jefferson Lab has been upgraded to allow for electron beam polarization measurements with better than 1% accuracy. The data acquisition system (DAQ) now includes an integrating mode, which eliminates several systematic uncertainties inherent in the original counting-DAQ setup. The photon calorimeter has been replaced with a Ce-doped Gd2SiO5 crystal, which has a bright output and fast response, and works well for measurements using the new integrating method at electron beam energies from 1 to 6 GeV.

  6. Subwavelength metrological chracterization by Mueller matrix polarimeter and finite difference time domain method

    NASA Astrophysics Data System (ADS)

    Adhikari, Achyut; Dev, Kapil; Asundi, Anand

    2016-11-01

    Wire grid polarizers (WGP), are sub-wavelength gratings with applications in display projection system due to their compact size, wide field of view and long-term stability. Measurement and testing of these structures are important to optimize their use. This is done by first measuring the Mueller matrix of the WGP using a Mueller matrix polarimeter. Next the finite difference time domain (FDTD) method is used to simulate a similar Mueller matrix thus providing the period and step height of the WGP. This approach may lead to more generic determination of sub-wavelength structures including diffractive optical structures.

  7. Laser polarimeter LP101M and its applications in liquid cromatography

    NASA Astrophysics Data System (ADS)

    Fajer, V.; Rodriguez, C.; Gonzalez, R.; Cossio, G.; Martinez, M.; Bravo, O.

    1996-02-01

    A high sensitivity laser polarimeter LP101M employing a He-Ne laser has been designed and constructed as a detector for liquid chromatography achieving a sensitivity better than 0.001 degree. The operation principle and technical characteristics of this instrument are described. A liquid gel chromatography column system suitable for sugar cane juice analysis was also designed and calibrated. It separated and analyzed the medium molecular weight carbohydrates and demonstrated the strong influence of these substances in the conventional polarimetric determinations.

  8. Computer-controlled near-infrared polarimeter featuring a new type of stress-birefringent modulator

    SciTech Connect

    West, S.C.; Schmidt, G.D.; Pawlicki, R.; Rieke, G.H.; Angel, R.P.

    1988-07-01

    The development of an astronomical polarimeter for the spectral region 1-2.6 microns is reported. The instrument incorporates a fused silica stress-birefringent modulator capable of producing square-wave polarimetric modulation of over 95 percent efficiency from dc to 2 Hz and quarter-wave retardation at wavelengths up to the K photometric bands. Possible applications of this instrument are examined, including the search for comparatively weak magnetic fields in white dwarf accretion binaries, the study of the nature of polarization in faint active galactic nuclei, and near-IR survey of isolated magnetic white dwarfs. 32 references.

  9. Upgraded photon calorimeter with integrating readout for Hall A Compton Polarimeter at Jefferson Lab

    DOE PAGES

    Friend, M.; Parno, D.; Benmokhtar, F.; ...

    2012-06-01

    The photon arm of the Compton polarimeter in Hall A of Jefferson Lab has been upgraded to allow for electron beam polarization measurements with better than 1% accuracy. The data acquisition system (DAQ) now includes an integrating mode, which eliminates several systematic uncertainties inherent in the original counting-DAQ setup. The photon calorimeter has been replaced with a Ce-doped Gd2SiO5 crystal, which has a bright output and fast response, and works well for measurements using the new integrating method at electron beam energies from 1 to 6 GeV.

  10. Monte-Carlo Estimation of the Inflight Performance of the GEMS Satellite X-Ray Polarimeter

    NASA Technical Reports Server (NTRS)

    Kitaguchi, Takao; Tamagawa, Toru; Hayato, Asami; Enoto, Teruaki; Yoshikawa, Akifumi; Kaneko, Kenta; Takeuchi, Yoko; Black, Kevin; Hill, Joanne; Jahoda, Keith; Krizmanic, John; Sturner, Steve; Griffiths, Scott; Kaaret, Philip; Marlowe, Hannah

    2014-01-01

    We report a Monte-Carlo estimation of the in-orbit performance of a cosmic X-ray polarimeter designed to be installed on the focal plane of a small satellite. The simulation uses GEANT for the transport of photons and energetic particles and results from Magboltz for the transport of secondary electrons in the detector gas. We validated the simulation by comparing spectra and modulation curves with actual data taken with radioactive sources and an X-ray generator. We also estimated the in-orbit background induced by cosmic radiation in low Earth orbit.

  11. First electron beam polarization measurements with a Compton polarimeter at Jefferson Laboratory

    SciTech Connect

    Maud Baylac; E. Burtin; C. Cavata; S. Escoffier; B. Frois; D. Lhuillier; F. Marie; J. Martino; D. Neyret; T. Pussieux; P.Y. Bertin; Kees de Jager; J. Mitchell

    2002-03-01

    A Compton polarimeter has been installed in Hall A at Jefferson Laboratory. This letter reports on the first electron beam polarization measurements performed during the HAPPEX experiment at an electron energy of 3.3 GeV and an average current of 40 muA. The heart of this device is a Fabry-Perot cavity which increased the luminosity for Compton scattering in the interaction region so much that a 1.4% statistical accuracy could be obtained within one hour, with a 3.3% total error.

  12. The High Altitude Observatory Coronagraph/Polarimeter on the Solar Maximum Mission

    NASA Technical Reports Server (NTRS)

    Macqueen, R. M.; Csoeke-Poeckh, A.; Hildner, E.; House, L.; Reynolds, R.; Stanger, A.; Tepoel, H.; Wagner, W.

    1980-01-01

    The paper examines the High Altitude Observatory Coronagraph/Polarimeter designed to produce images of the solar corona in 7 wavelength bands in the visible spectral range, and to be flown on the NASA Solar Maximum Mission satellite. The spectral bands were chosen to exclude or include 'chromospheric' spectral lines, so as to allow discrimination between ejecta at coronal and chromospheric temperatures. The major goals of the instrument include: (1) observation of the corona in the flare process and of the ejecta from the flare site and the overlying corona, and (2) examination of the evolution of the solar corona near the period of solar maximum activity.

  13. SOLPEX x-ray polarimeter detector luminescence background calculated using Geant4 simulation software

    NASA Astrophysics Data System (ADS)

    Gorgolewski, Aleksander; Barylak, Jaromir; Steślicki, Marek; Szaforz, Å.»aneta; BÄ kała, Jarosław

    2016-09-01

    The Soft X-ray Solar polarimeter-spectrometer (SOLPEX) experiment is planned to be placed in Roscosmos' Multipurpose Laboratory Module "NAUKA" on International Space Station (ISS) in 2019. The experiment is design to detect polarization and X-ray spectra of solar flares. Due to very high, few percent, linear polarization detection limit, accurate background estimation and modeling is crucial. Calculating the background photoelectric effect, Compton scattering and Bremsstrahlung were taken into account. Luminescence background from particles produced in solar flares was simulated using Geant4. Additionally, theoretical spectra was modeled in order to simulate full SOLPEX detector response for M5 and X1 solar flare classes.

  14. POLOCAM: a millimeter wavelength cryogenic polarimeter prototype for MUSIC-POL

    NASA Astrophysics Data System (ADS)

    Laurent, Glenn T.; Vaillancourt, John E.; Savini, Giorgio; Ade, Peter A. R.; Beland, Stephane; Glenn, Jason; Hollister, Matthew I.; Maloney, Philip R.; Sayers, Jack

    2012-09-01

    As a proof-of-concept, we have constructed and tested a cryogenic polarimeter in the laboratory as a prototype for the MUSIC instrument (Multiwavelength Sub/millimeter Kinetic Inductance Camera). The POLOCAM instrument consists of a rotating cryogenic polarization modulator (sapphire half-waveplate) and polarization analyzer (lithographed copper polarizers deposited on a thin film) placed into the optical path at the Lyot stop (4K cold pupil stop) in a cryogenic dewar. We present an overview of the project, design and performance results of the POLOCAM instrument (including polarization efficiencies and instrumental polarization), as well as future application to the MUSIC-POL instrument.

  15. Relaxation Method for Navier-Stokes Equation

    NASA Astrophysics Data System (ADS)

    de Oliveira, P. M. C.

    2012-04-01

    The motivation for this work was a simple experiment [P. M. C. de Oliveira, S. Moss de Oliveira, F. A. Pereira and J. C. Sartorelli, preprint (2010), arXiv:1005.4086], where a little polystyrene ball is released falling in air. The interesting observation is a speed breaking. After an initial nearly linear time-dependence, the ball speed reaches a maximum value. After this, the speed finally decreases until its final, limit value. The provided explanation is related to the so-called von Kármán street of vortices successively formed behind the falling ball. After completely formed, the whole street extends for some hundred diameters. However, before a certain transient time needed to reach this steady-state, the street is shorter and the drag force is relatively reduced. Thus, at the beginning of the fall, a small and light ball may reach a speed superior to the sustainable steady-state value. Besides the real experiment, the numerical simulation of a related theoretical problem is also performed. A cylinder (instead of a 3D ball, thus reducing the effective dimension to 2) is positioned at rest inside a wind tunnel initially switched off. Suddenly, at t = 0 it is switched on with a constant and uniform wind velocity ěc{V} far from the cylinder and perpendicular to it. This is the first boundary condition. The second is the cylinder surface, where the wind velocity is null. In between these two boundaries, the velocity field is determined by solving the Navier-Stokes equation, as a function of time. For that, the initial condition is taken as the known Stokes laminar limit V → 0, since initially the tunnel is switched off. The numerical method adopted in this task is the object of the current text.

  16. Ultraviolet spectrometer and polarimeter (UVSP) catalog of observations. Volume 1: Experiments 1-30719, February 1980 - April 1985

    NASA Technical Reports Server (NTRS)

    Henze, William, Jr.

    1993-01-01

    A catalog of observations (experiments) obtained by the Ultraviolet Spectrometer and Polarimeter (UVSP) on the Solar Maximum Mission (SMM) from Feb. 1980 to Nov. 1989 is presented. The information for each entry includes the time of each observation, the observed position of the Sun, the spacecraft roll angle, the slit used, and instrument parameters such as raster size, pixel spacing, wavelength, polarimeter usage, gate time, etc. The document is split into three volumes: Volume 1 contains experiments 1-30719 (February 1980-April 1985); Volume 2 contains experiments 30720-63057 (April 1985-February 1988); and Volume 3 contains experiments 63058-99771 (February l988-November 1989).

  17. Ultraviolet spectrometer and polarimeter (UVSP) catalog of observations. Volume 2: Experiments 30720-63057, April 1985 - February 1988

    NASA Technical Reports Server (NTRS)

    Henze, William, Jr.

    1993-01-01

    A catalog of observations (experiments) obtained by the Ultraviolet Spectrometer and Polarimeter (UVSP) on the Solar Maximum Mission (SMM) from Feb. 1980 to Nov. 1989 is presented. The information for each entry includes the time of each observation, the observed position of the Sun, the spacecraft roll angle, the slit used, and instrument parameters such as raster size, pixel spacing, wavelength, polarimeter usage, gate time, etc. The document is split into three volumes: Volume 1 contains experiments 1-30719 (February 1980-April 1985); Volume 2 contains experiments 30720-63057 (April 1985-February 1988); and Volume 3 contains experiments 63058-99771 (February 1988-November 1989).

  18. Ultraviolet Spectrometer and Polarimeter (UVSP) catalog of observations. Volume 3: Experiments 63058-99771 (February 1988 - November 1989)

    NASA Technical Reports Server (NTRS)

    Henze, William, Jr.

    1993-01-01

    A catalog of a observations (experiments) obtained by the Ultraviolet Spectrometer and Polarimeter (UVSP) on the Solar Maximum Mission (SMM) from Nov. 1980 to Nov. 1989 is provided. The information for each entry includes the time of each observation, the observed position of the Sun, the spacecraft roll angle, the slit used, and instrument parameters such as raster size, pixel spacing, wavelength, polarimeter usage, gate time, etc. The document is split into three volumes: Volume 1 contains experiments 1-30719 (Feb. 1980 - Apr. 1985); Volume 2 contains experiments 30720-63057 (Apr. 1985 - Feb. 1988); and Volume 3 contains experiments 63058-99771 (Feb. 1988 - Nov. 1989).

  19. Monomeric red fluorescent proteins with a large Stokes shift.

    PubMed

    Piatkevich, Kiryl D; Hulit, James; Subach, Oksana M; Wu, Bin; Abdulla, Arian; Segall, Jeffrey E; Verkhusha, Vladislav V

    2010-03-23

    Two-photon microscopy has advanced fluorescence imaging of cellular processes in living animals. Fluorescent proteins in the blue-green wavelength range are widely used in two-photon microscopy; however, the use of red fluorescent proteins is limited by the low power output of Ti-Sapphire lasers above 1,000 nm. To overcome this limitation we have developed two red fluorescent proteins, LSS-mKate1 and LSS-mKate2, which possess large Stokes shifts with excitation/emission maxima at 463/624 and 460/605 nm, respectively. These LSS-mKates are characterized by high pH stability, photostability, rapid chromophore maturation, and monomeric behavior. They lack absorbance in the green region, providing an additional red color to the commonly used red fluorescent proteins. Substantial overlap between the two-photon excitation spectra of the LSS-mKates and blue-green fluorophores enables multicolor imaging using a single laser. We applied this approach to a mouse xenograft model of breast cancer to intravitally study the motility and Golgi-nucleus alignment of tumor cells as a function of their distance from blood vessels. Our data indicate that within 40 mum the breast cancer cells show significant polarization towards vessels in living mice.

  20. The motional Stark effect polarimeter in the HL-2A tokamak.

    PubMed

    Yu, D L; Wei, Y L; Xia, F; Cao, J Y; Chen, C Y; Liu, L; Chen, W J; Ji, X Q; Liu, Y; Yan, L W; Yang, Q W; Duan, X R

    2014-05-01

    A 7-channel motional Stark effect polarimeter based on four polarizers and a spectrometer has been developed in the HL-2A tokamak, which is the first time successful utilizing this kind of polarimeter on a tokamak. The accuracy of the angle can reach ±0.25° in the calibration experiments. Pilot experiments of measuring the magnetic pitch angle have been successfully carried out in the weak motional Stark effect plasma discharge with toroidal magnetic field of ~1.3 T and beam energy of ~25 keV/amu. The pitch angles of magnetic field are obtained for 7 spatial points covering 24 cm along major radius with time resolution of 40 ms; the profiles of safety factor are obtained by combining with the Equilibrium and Reconstruction Fitting Code. The core value of safety factor (q) is less than 1 during the sawtooth oscillation and the position of q = 1 surface is well consistent with the results measured by soft X-ray array.

  1. Measurements of beam-driven instabilities with the upgraded MST interferometer-polarimeter

    NASA Astrophysics Data System (ADS)

    Parke, E.; Anderson, J. K.; Brower, D. L.; Ding, W. X.

    2016-10-01

    Neutral beam injection (NBI) in MST produces a core-localized fast ion population that modifies the plasma equilibrium and drives a rich variety of instabilities. These instabilities include energetic particle modes (EPMs) and Alfvénic modes that can produce an avalanche process leading to significantly enhanced fast ion transport, as well as chirping modes. The MST FIR interferometer-polarimeter system has high-bandwidth and low phase noise and has previously been used to characterize density fluctuations correlated with many of these instabilities, as well as internal magnetic fluctuations associated with the dominant, n = 5 EPM. However, many of the Alfvénic and chirping modes were too weak to observe in polarimetry measurements in previous studies. Recent upgrades to the interferometer-polarimeter have further reduced the noise floor and extended the accessible bandwidth for fluctuation measurements. Initial measurements of fast ion driven instabilities with the upgraded system will be presented. Improved measurements of internal structure may be important for understanding mode dynamics and particle transport. Work supported by U.S. D.O.E.

  2. First results of the J-TEXT high-resolution 3-wave polarimeter-interferometer system

    NASA Astrophysics Data System (ADS)

    Zhuang, G.; Chen, J.; Li, Q.; Gao, L.; Wang, Z. J.; Liu, Y.; Chen, W.

    2013-10-01

    A far-infrared laser polarimeter-interferometer system based on Three-wave technique has been established on the J-TEXT tokamak. The system determines Faraday angle by measuring phase difference between two collinear, counter-rotating, circularly polarized laser beams, and acquires line-integrated electron density simultaneously by phase comparison between the two beams and a third local oscilate (LO) beam. Three seperately pumped HCOOH lasers at 432 μm are adopted as sources, suppling more than 100 mW power output in sum. Parabolic mirrors are used to expand probe beams to 450 mm wide, covering ~ 80% of plasma cross section, which allows profile measurement with high spatial resolution. First experimental results of the polarimeter-interferometer have been obtained. 12 chords (3 cm chord spacing) simultaneous polarimetric and interferometric measurements are achieved, with phase resolution up to 0.1° at bandwidth of 50 kHz. With the high temporal and phase resolution, perturbations associated with the sawtooth cycle and MHD activity have been observed.

  3. The motional Stark effect polarimeter in the HL-2A tokamak

    SciTech Connect

    Yu, D. L. Wei, Y. L.; Xia, F.; Cao, J. Y.; Chen, C. Y.; Liu, L.; Chen, W. J.; Ji, X. Q.; Liu, Y.; Yan, L. W.; Yang, Q. W.; Duan, X. R.

    2014-05-15

    A 7-channel motional Stark effect polarimeter based on four polarizers and a spectrometer has been developed in the HL-2A tokamak, which is the first time successful utilizing this kind of polarimeter on a tokamak. The accuracy of the angle can reach ±0.25° in the calibration experiments. Pilot experiments of measuring the magnetic pitch angle have been successfully carried out in the weak motional Stark effect plasma discharge with toroidal magnetic field of ∼1.3 T and beam energy of ∼25 keV/amu. The pitch angles of magnetic field are obtained for 7 spatial points covering 24 cm along major radius with time resolution of 40 ms; the profiles of safety factor are obtained by combining with the Equilibrium and Reconstruction Fitting Code. The core value of safety factor (q) is less than 1 during the sawtooth oscillation and the position of q = 1 surface is well consistent with the results measured by soft X-ray array.

  4. 10-channel far-infrared polarimeter for the tokamak à configuration variable

    NASA Astrophysics Data System (ADS)

    Blanchard, P.; Behn, R.; Weisen, H.; Zhuchkova, A.

    2006-10-01

    A new far-infrared polarimeter diagnostic for the tokamak à configuration variable (TCV) is under construction at CRPP. It uses two FIR lasers at 432.5μm, optically pumped by a 120W continuous wave CO2 laser. The two FIR cavities will be detuned such that the combination of the beams, using a method proposed by Dodel and Kunz [Infrared Phys. 18, 773 (1978)], produces a single beam with a linear polarization rotating at the difference frequency (set to 750kHz). For measurements across the minor radius of TCV, this beam will be split into ten beams, each equipped with a Schottky barrier diode as detector. Faraday rotation angles will be measured by coherent detection. In order to optimize the sensitivity of the polarimeter for the parameter range of interest [ne(0)<3×1019m-3], we have chosen to keep it separate from the existing 14-channel interferometer operating at 214μm. This also leads to substantial simplification of the design and signal processing. The design of the system as well as its expected sensitivity are presented and discussed. The required accuracy to measure profiles of current density and safety factor for typical operating scenarios with internal transport barriers on TCV (including cases with reversed magnetic shear) is assessed by numerical simulations.

  5. A Second Order Continuum Theory of Fluids - Beyond the Navier-Stokes Equations

    NASA Astrophysics Data System (ADS)

    Paolucci, Samuel

    2016-11-01

    The Navier-Stokes equations have proved very valuable in modeling fluid flows over the last two centuries. However, there are some cases where it has been demonstrated that they do not provide accurate results. In such cases, very large variations in velocity and/or thermal fields occur in the flows. It is recalled that the Navier-Stokes equations result from linear approximations of constitutive quantities. Using continuum mechanics principles, we derive a second order constitutive theory that application of which should provide more accurate results is such cases. One important case is the structure of gas-dynamic shock waves. It has been demonstrated experimentally that the Navier-Stokes formulation yields incorrect shock profiles even at moderate Mach numbers. Current continuum theories, and indeed most statistical mechanics theories, that have been advanced to reconcile such discrepancies have not been fully successful. Thus, application of the second order theory based solely on a continuum formulation provides an excellent test problem. Results of the second-order equations applied to the shock structure are obtained for monatomic and diatomic gases over a large range of Mach numbers and are compared to experimental results.

  6. Approximate Stokes Drift Profiles and their use in Ocean Modelling

    NASA Astrophysics Data System (ADS)

    Breivik, Oyvind; Bidlot, Jea-Raymond; Janssen, Peter A. E. M.; Mogensen, Kristian

    2016-04-01

    Deep-water approximations to the Stokes drift velocity profile are explored as alternatives to the monochromatic profile. The alternative profiles investigated rely on the same two quantities required for the monochromatic profile, viz the Stokes transport and the surface Stokes drift velocity. Comparisons against parametric spectra and profiles under wave spectra from the ERA-Interim reanalysis and buoy observations reveal much better agreement than the monochromatic profile even for complex sea states. That the profiles give a closer match and a more correct shear has implications for ocean circulation models since the Coriolis-Stokes force depends on the magnitude and direction of the Stokes drift profile and Langmuir turbulence parameterizations depend sensitively on the shear of the profile. Of the two Stokes drift profiles explored here, the profile based on the Phillips spectrum is by far the best. In particular, the shear near the surface is almost identical to that influenced by the f-5 tail of spectral wave models. The NEMO general circulation ocean model was recently extended to incorporate the Stokes-Coriolis force along with two other wave-related effects. The ECWMF coupled atmosphere-wave-ocean ensemble forecast system now includes these wave effects in the ocean model component (NEMO).

  7. Stokes vector formalism based second harmonic generation microscopy

    NASA Astrophysics Data System (ADS)

    Qiu, Jianjun; Mazumder, Nirmal; Tsai, Han-Ruei; Hu, Chih-Wei; Kao, Fu-Jen

    2012-02-01

    In this study, we have developed a four-channel Stokes vector formalism based second harmonic generation (SHG) microscopy to map and analyze SHG signal. A four-channel Stokesmeter setup is calibrated and integrated into a laser scanning microscope to measure and characterize the SH's corresponding Stokes parameters. We are demonstrating the use of SH and its Stokes parameters to visualize the birefringence and crystalline orientation of KDP and collagen. We believe the developed method can reveal unprecedented information for biomedical and biomaterial studies.

  8. Preconditioning the pressure operator for the time dependent Stokes problem

    SciTech Connect

    Bramble, J.H.; Pasciak, J.E.

    1994-12-31

    In implicit time stepping procedures for the linearized Navier Stokes equations, a linear perturbed Stokes problem must be solved at each time step. Many methods for doing this require a good preconditioner for the resulting pressure operator (Schur complement). In contrast to the time independent Stokes equations where the pressure operator is well conditioned, the pressure operator for the perturbed system becomes more illconditioned as the time step is reduced (and/or the Reynolds number is increased). The authors describe the method for solving the coupled velocity/pressure systems and, in particular, show how to construct good preconditioners for the poorly conditioned pressure operator.

  9. Numerical Prediction Methods (Reynolds-Averaged Navier-Stokes Simulations of Transonic Separated Flows)

    NASA Technical Reports Server (NTRS)

    Mehta, Unmeel; Lomax, Harvard

    1981-01-01

    During the past five years, numerous pioneering archival publications have appeared that have presented computer solutions of the mass-weighted, time-averaged Navier-Stokes equations for transonic problems pertinent to the aircraft industry. These solutions have been pathfinders of developments that could evolve into a major new technological capability, namely the computational Navier-Stokes technology, for the aircraft industry. So far these simulations have demonstrated that computational techniques, and computer capabilities have advanced to the point where it is possible to solve forms of the Navier-Stokes equations for transonic research problems. At present there are two major shortcomings of the technology: limited computer speed and memory, and difficulties in turbulence modelling and in computation of complex three-dimensional geometries. These limitations and difficulties are the pacing items of the continuing developments, although the one item that will most likely turn out to be the most crucial to the progress of this technology is turbulence modelling. The objective of this presentation is to discuss the state of the art of this technology and suggest possible future areas of research. We now discuss some of the flow conditions for which the Navier-Stokes equations appear to be required. On an airfoil there are four different types of interaction of a shock wave with a boundary layer: (1) shock-boundary-layer interaction with no separation, (2) shock-induced turbulent separation with immediate reattachment (we refer to this as a shock-induced separation bubble), (3) shock-induced turbulent separation without reattachment, and (4) shock-induced separation bubble with trailing edge separation.

  10. Spectral features of anti-Stokes and Stokes modes generated by stimulated Raman scattering in liquid toluene

    NASA Astrophysics Data System (ADS)

    Yadav, Suchita; Kumar, Govind; Vijaya, R.

    2016-10-01

    Stimulated Raman scattering leading to the generation of four first-order Stokes modes at shifts of 862.9, 1035, 2967 and 3086 cm-1, one second-order Stokes mode at a shift of 2032.5 cm-1 and one first-order anti-Stokes mode at a shift of 946.3 cm-1 has been measured in an experiment using liquid toluene. The observed shifts are assigned to the earlier reported Raman shifts of toluene at 786, 1006, 2979, 3060 cm-1 due to ring-breathing mode, ring deformation mode, CH3 stretching mode and CH stretching mode, respectively. Simultaneous measurement of all the Raman modes, including the second-order Stokes and first-order anti-Stokes, and their correct assignment to the vibrational modes of toluene is not reported widely in earlier work. The Raman modes generated from toluene emerge as concentric rings of different diameters. The phase-matching angle for anti-Stokes generation is thus measured and compared with the expected value from calculation. The spectral broadening observed near two of the modes is explained with the help of Raman-active modes of toluene reported earlier by others. Raman shifts, threshold levels, gain and beam profile of all the modes, along with the phase matching of the anti-Stokes mode, are reported.

  11. Plasmonic micropolarizers for full Stokes vector imaging

    NASA Astrophysics Data System (ADS)

    Peltzer, J. J.; Bachman, K. A.; Rose, J. W.; Flammer, P. D.; Furtak, T. E.; Collins, R. T.; Hollingsworth, R. E.

    2012-06-01

    Polarimetric imaging using micropolarizers integrated on focal plane arrays has previously been limited to the linear components of the Stokes vector because of the lack of an effective structure with selectivity to circular polarization. We discuss a plasmonic micropolarizing filter that can be tuned for linear or circular polarization as well as wavelength selectivity from blue to infrared (IR) through simple changes in its horizontal geometry. The filter consists of a patterned metal film with an aperture in a central cavity that is surrounded by gratings that couple to incoming light. The aperture and gratings are covered with a transparent dielectric layer to form a surface plasmon slab waveguide. A metal cap covers the aperture and forms a metal-insulator-metal (MIM) waveguide. Structures with linear apertures and gratings provide sensitivity to linear polarization, while structures with circular apertures and spiral gratings give circular polarization selectivity. Plasmonic TM modes are transmitted down the MIM waveguide while the TE modes are cut off due to the sub-wavelength dielectric thickness, providing the potential for extremely high extinction ratios. Experimental results are presented for micropolarizers fabricated on glass or directly into the Ohmic contact metallization of silicon photodiodes. Extinction ratios for linear polarization larger than 3000 have been measured.

  12. Multispectral Stokes polarimetry for dermatoscopic imaging

    NASA Astrophysics Data System (ADS)

    Castillejos, Y.; Martínez-Ponce, Geminiano; Mora-Nuñez, Azael; Castro-Sanchez, R.

    2015-12-01

    Most of skin pathologies, including melanoma and basal/squamous cell carcinoma, are related to alterations in external and internal order. Usually, physicians rely on their empirical expertise to diagnose these ills normally assisted with dermatoscopes. When there exists skin cancer suspicion, a cytology or biopsy is made, but both laboratory tests imply an invasive procedure. In this regard, a number of non-invasive optical techniques have been proposed recently to improve the diagnostic certainty and assist in the early detection of cutaneous cancer. Herein, skin optical properties are derived with a multispectral polarimetric dermatoscope using three different illumination wavelength intervals centered at 470, 530 and 635nm. The optical device consist of two polarizing elements, a quarter-wave plate and a linear polarizer, rotating at a different angular velocity and a CCD array as the photoreceiver. The modulated signal provided by a single pixel in the acquired image sequence is analyzed with the aim of computing the Stokes parameters. Changes in polarization state of selected wavelengths provide information about the presence of skin pigments such as melanin and hemoglobin species as well as collagen structure, among other components. These skin attributes determine the local physiology or pathology. From the results, it is concluded that optical polarimetry will provide additional elements to dermatologists in their diagnostic task.

  13. Optimal propulsive flapping in Stokes flows.

    PubMed

    Was, Loïc; Lauga, Eric

    2014-03-01

    Swimming fish and flying insects use the flapping of fins and wings to generate thrust. In contrast, microscopic organisms typically deform their appendages in a wavelike fashion. Since a flapping motion with two degrees of freedom is able, in theory, to produce net forces from a time-periodic actuation at all Reynolds numbers, we compute in this paper the optimal flapping kinematics of a rigid spheroid in a Stokes flow. The hydrodynamics for the force generation and energetics of the flapping motion is solved exactly. We then compute analytically the gradient of a flapping efficiency in the space of all flapping gaits and employ it to derive numerically the optimal flapping kinematics as a function of the shape of the flapper and the amplitude of the motion. The kinematics of optimal flapping are observed to depend weakly on the flapper shape and are very similar to the figure-eight motion observed in the motion of insect wings. Our results suggest that flapping could be a exploited experimentally as a propulsion mechanism valid across the whole range of Reynolds numbers.

  14. Chaos Synchronization in Navier-Stokes Turbulence

    NASA Astrophysics Data System (ADS)

    Lalescu, Cristian; Meneveau, Charles; Eyink, Gregory

    2013-03-01

    Chaos synchronization (CS) has been studied for some time now (Pecora & Carroll 1990), for systems with only a few degrees of freedom as well as for systems described by partial differential equations (Boccaletti et al 2002). CS in general is said to be present in coupled dynamical systems when a specific property of each system has the same time evolution for all, even though the evolution itself is chaotic. The Navier-Stokes (NS) equations describe the velocity for a wide range of fluids, and their solutions are usually called turbulent if fluctuation amplitudes decrease as a power of their wavenumber. There have been some studies of CS for continuous systems (Kocarev et al 1997), but CS for NS turbulence seems not to have been investigated so far. We focus on the synchronization of the small scales of a turbulent flow for which the time history of large scales is prescribed. Our DNS results show that high-wavenumbers in turbulence are fully slaved to modes with wavenumbers up to a critical fraction of the Kolmogorov dissipation wavenumber. The motivation for our work is to study deeply sub-Kolmogorov scales in fully developed turbulence (Schumacher 2007), which we found to be recoverable even at very high Reynolds number from simulations with moderate resolutions. This work is supported by the National Science Foundation's CDI-II program, project CMMI-0941530

  15. Chaos Synchronization in Navier-Stokes Turbulence

    NASA Astrophysics Data System (ADS)

    Lalescu, Cristian C.; Meneveau, Charles; Eyink, Gregory L.

    2012-11-01

    Chaos synchronization (CS) has been studied for some time now (Pecora & Carroll 1990), for systems with only a few degrees of freedom as well as for systems described by partial differential equations (Boccaletti et al. 2002). CS in general is said to be present in a pair of coupled dynamical systems when a specific property of each system has the same time evolution for both, even though the evolution itself is chaotic. There have been some studies of CS for systems with an infinite number of degrees of freedom (Kocarev et al. 1997), but CS for Navier-Stokes (NS) turbulence seems not to have been investigated so far. We focus on the synchronization of the small scales of a turbulent flow for which the time history of large scales is prescribed. We present DNS results which show that high-wavenumbers in turbulence are fully slaved to modes with wavenumbers up to a critical fraction of the Kolmogorov dissipation wavenumber. We compare our results with related ideas of ``approximate inertial manifolds.'' The motivation for our work is to study deeply sub-Kolmogorov scales in fully developed turbulence (Schumacher 2007), which we show are recoverable even at very high Reynolds number from simulations that only resolve down to about the Kolmogorov scale. This work is supported by the National Science Foundation's CDI-II program, project CMMI-0941530.

  16. Formulation of boundary conditions for the multigrid acceleration of the Euler and Navier Stokes equations

    NASA Technical Reports Server (NTRS)

    Jentink, Thomas Neil; Usab, William J., Jr.

    1990-01-01

    An explicit, Multigrid algorithm was written to solve the Euler and Navier-Stokes equations with special consideration given to the coarse mesh boundary conditions. These are formulated in a manner consistent with the interior solution, utilizing forcing terms to prevent coarse-mesh truncation error from affecting the fine-mesh solution. A 4-Stage Hybrid Runge-Kutta Scheme is used to advance the solution in time, and Multigrid convergence is further enhanced by using local time-stepping and implicit residual smoothing. Details of the algorithm are presented along with a description of Jameson's standard Multigrid method and a new approach to formulating the Multigrid equations.

  17. The Louis Stokes Health Sciences Library: the Howard University move experience

    PubMed Central

    Bryant, Darcel A.

    2004-01-01

    The Louis Stokes Health Sciences Library attributes its successful move to early planning and preparation. Professional literature on the subject as well as consultation with other experienced library personnel also proved beneficial. Utilizing these resources, the committees devised a strategy that supported the library's mission to provide excellent and complete information services for the advancement of health sciences. This paper describes the Howard University Health Sciences Library move experience and offers practical advice for planning a library move. We hope that the information shared will assist other libraries facing a similar challenge. PMID:15098055

  18. Coherent anti-Stokes Raman scattering microscopy: overcoming technical barriers for clinical translation.

    PubMed

    Tu, Haohua; Boppart, Stephen A

    2014-01-01

    Clinical translation of coherent anti-Stokes Raman scattering microscopy is of great interest because of the advantages of noninvasive label-free imaging, high sensitivity, and chemical specificity. For this to happen, we have identified and review the technical barriers that must be overcome. Prior investigations have developed advanced techniques (features), each of which can be used to effectively overcome one particular technical barrier. However, the implementation of one or a small number of these advanced features in previous attempts for clinical translation has often introduced more tradeoffs than benefits. In this review, we outline a strategy that would integrate multiple advanced features to overcome all the technical barriers simultaneously, effectively reduce tradeoffs, and synergistically optimize CARS microscopy for clinical translation. The operation of the envisioned system incorporates coherent Raman micro-spectroscopy for identifying vibrational biomolecular markers of disease and single-frequency (or hyperspectral) Raman imaging of these specific biomarkers for real-time in vivo diagnostics and monitoring.

  19. Coherent anti-Stokes Raman spectroscopy: Understanding the essentials

    NASA Astrophysics Data System (ADS)

    Ariunbold, Gombojav O.; Altangerel, Narangerel

    2016-12-01

    This paper is a brief overview to coherent anti- Stokes Raman spectroscopic technique and introduces the strengths and barriers to its use all based on the interpretation of simple theoretical formulae. The use of the Gaussian ultrashort pulses is highlighted as a practical elucidatory reconstruction tool of coherent Raman spectra. The paper presents the integral formulae for coherent anti-Stokes and Stokes Raman scattering, and discusses the closed-form solutions, its complex error function, and the delay time formula for enhancement of the inferred pure coherent Raman spectra. As an example, the timeresolved coherent Stokes Raman scattering experimental observations are quantitatively elucidated.Understanding the essentials of coherent Raman spectroscopy, therefore, promotes the importance of a number of experiments including the ones utilizing a broadband excitation with a narrowband delayed probing for successful background suppression.

  20. Intercomparison of Ground-Based Aerosol Retrievals Using Spex Spectro-Polarimeters

    NASA Astrophysics Data System (ADS)

    Smit, M.; Rietjens, J.; van Harten, G.; di Noia, A.; Hasekamp, O. P.; Snik, F.; Keller, C. A.

    2014-12-01

    Multi-angle spectro-polarimetry holds great potential as a remote sensing technique to derive aerosol information. A consortium of Dutch research institutes has developed a multi-angle spectro-polarimeter that is based on a novel method for measuring the state of linear polarization: spectral modulation. Through a series of carefully selected birefringent crystals, the polarization state of scattered sunlight is encoded in a sinusoidal modulation in the intensity spectrum.The technique is entirely passive. As consequence of the method is that spectral flux and state of polarization are measured simultaneouslyin a single measurement of a target scene. The technique has been employed in two instrument realizations, that are both referenced by the name SPEX: SPectro-polarimeter Experiment. A compact prototype SPEX instrument for space-based observations operates in the 400-800nm wavelength range and consists of nine fixed viewing apertures with a swath of 7 degrees each and an angular resolution of 1deg x 1deg. The space-SPEX instrument is currently being made fit to perform aerosol characterization campaigns on-board an ER-2 research aircraft together with NASA's Research Scanning Polarimeter. Another realization is groundSPEX, that was developed specifically for air-quality observations made from the ground. Both instruments were calibrated using 100% polarized light, assuming a bias-free linear response. This was validated in different ways. Using a recently developed polarization calibration stimulus we demonstrate the excellent polarimetric performance of the SPEX prototype: a polarimetric accuracy better than 0.002 + 0.01*DoLP. The overall random polarization error of groundSPEX was determined to be 0.005 by fitting the angular dependence of principle plane polarization measurements. We will present results of ground-based measurements with both SPEX instruments. We will intercompare aerosol characterization parameters such as Aerosol Optical Thickness

  1. Evaluation of LIDAR/Polarimeter Aerosol Measurements by In Situ Instrumentation during DEVOTE

    NASA Astrophysics Data System (ADS)

    Beyersdorf, A. J.; Ziemba, L. D.; Anderson, B. E.; Dolgos, G.; Ottaviani, M.; Obland, M. D.; Rogers, R.; Thornhill, K. L.; Winstead, E. L.; Yang, M. M.; Hair, J. W.

    2011-12-01

    Combined measurements from LIDAR (LIght Detection And Ranging) and polarimeter instruments provide the opportunity for enhanced satellite observations of aerosol properties including retrievals of aerosol optical depth, single scattering albedo, effective radius, and refractive index. However, these retrievals (specifically for refractive index) have not been fully vetted and require additional intercomparisons with in situ measurements to improve accuracy. Proper validation of these combined LIDAR/polarimeter retrievals requires evaluation in varying atmospheric conditions and of varying aerosol composition. As part of this effort, two NASA Langley King Air aircraft have been outfitted to provide coordinated measurements of aerosol properties. One will be used as a remote sensing platform with the NASA Langley high-spectral resolution LIDAR (HSRL) and NASA GISS research scanning polarimeter (RSP). The second aircraft has been modified for use as an in situ platform and will house a suite of aerosol microphysical instrumentation, a pair of diode laser hygrometers (DLHs) for water vapor and cloud extinction measurements, and a polarized imaging nephelometer (PI-Neph). The remote sensing package has flown in a variety of campaigns, however only rarely has been able to coordinate with in situ measurements. The use of two collocated aircraft will allow for future coordinated flights to provide a more complete dataset for evaluation of aerosol retrievals and allow for fast-response capability. Results from the first coordinated King Air flights as part of DEVOTE (Development and Evaulation of satellite ValidatiOn Tools by Experimenters) will be presented. Flights are planned out of Hampton, VA during September and October 2011 including underflights of the CALIPSO satellite and overflights of ground-based AERONET (AErosol RObotic NETwork) sites. These will provide a comparison of aerosol properties between in situ and remote instruments (ground, aircraft, and satellite

  2. 3-D adaptive grid Navier-Stokes rocket plume calculations

    NASA Astrophysics Data System (ADS)

    Holcomb, J. Eric

    1991-01-01

    Three-dimensional adaptive-grid full Navier-Stokes calculations performed for the base region and plume of the Minuteman first stage and a simplified version of the Titan first stage are used to demonstrate the applicability of the Navier-Stokes flow solver, EAGLE adaptive grid generator, and k-epsilon turbulence model to rocket plume flowfields. The calculations include realistic exhaust gas thermodynamic properties, with frozen chemistry.

  3. Compressible Navier-Stokes Equations with Revised Maxwell's Law

    NASA Astrophysics Data System (ADS)

    Hu, Yuxi; Racke, Reinhard

    2017-03-01

    We investigate the compressible Navier-Stokes equations where the constitutive law for the stress tensor given by Maxwell's law is revised to a system of relaxation equations for two parts of the tensor. The global well-posedness is proved as well as the compatibility with the classical compressible Navier-Stokes system in the sense that, for vanishing relaxation parameters, the solutions to the Maxwell system are shown to converge to solutions of the classical system.

  4. Navier-Stokes computations for circulation controlled airfoils

    NASA Technical Reports Server (NTRS)

    Pulliam, T. H.; Jesperen, D. C.; Barth, T. J.

    1986-01-01

    Navier-Stokes computations of subsonic to transonic flow past airfoils with augmented lift due to rearward jet blowing over a curved trailing edge are presented. The approach uses a spiral grid topology. Solutions are obtained using a Navier-Stokes code which employs an implicit finite difference method, an algebraic turbulence model, and developments which improve stability, convergence, and accuracy. Results are compared against experiments for no jet blowing and moderate jet pressures and demonstrate the capability to compute these complicated flows.

  5. Analysis of regularized Navier-Stokes equations. I, II

    NASA Technical Reports Server (NTRS)

    Ou, Yuh-Roung; Sritharan, S. S.

    1991-01-01

    A regularized form of the conventional Navier-Stokes equations is analyzed. The global existence and uniqueness are established for two classes of generalized solutions. It is shown that the solution of this regularized system converges to the solution of the conventional Navier-Stokes equations for low Reynolds numbers. Particular attention is given to the structure of attractors characterizing the solutions. Both local and global invariant manifolds are found, and the regularity properties of these manifolds are analyzed.

  6. Singularity of Navier-Stokes Equations Leading to Turbulent Transition

    NASA Astrophysics Data System (ADS)

    Dou, Hua-Shu; Fluid Mechanics Research Team

    2014-11-01

    As is well known, there is discontinuity during the transition from laminar flow to turbulence in the time-averaged Navier-Stokes equations. In other words, singularity may implicitly exist in the Navier-Stokes equations. Transition of a laminar flow to turbulence must be implemented via the singularity. However, how the singularity of Navier-Stokes equations is related to the turbulent transition is not understood. In this study, the singularity possibly hidden in the Navier-Stokes equation is exactly derived by mathematical treatment. Then, it is found that for pressure driven flows, the singularity of Navier-Stokes equations corresponds to the inflection point on the velocity profile. Since the rate of amplification to a disturbance at the inflection point is infinite, the laminar flow is able to involve into turbulence at this point firstly at a sufficient high Reynolds number. This is the reason why turbulent spot is formed at the location of inflection point. It is further demonstrated that the existence of the singularity in the time-averaged Navier-Stokes equations is the necessary and sufficient condition for the turbulent transition in pressure driven flows. These results agrees well with the findings from the recent proposed energy gradient method. Professor in Fluid Mechanics; AIAA Associate Fellow.

  7. Combined spontaneous Stokes and coherent anti-Stokes Raman scattering spectroscopy

    NASA Astrophysics Data System (ADS)

    Becker, Karina; Kiefer, Johannes

    2016-05-01

    The simultaneous determination of multiple parameters is the key in the characterization of processes and materials that change with time. In combustion environments, the combined measurement of temperature and chemical composition is particularly desirable. In the present work, possible approaches for the simultaneous application of spontaneous Raman scattering (RS) and coherent anti-Stokes Raman scattering (CARS) spectroscopy are proposed and analyzed. While RS provides concentration information of all major species, vibrational CARS is a highly accurate thermometry tool at flame conditions. Five experimentally feasible CARS-RS schemes are identified and discussed with respect to signal intensity, measurement volume, and experimental complexity. From this analysis, one scheme was found to be the best option. It utilizes a broadband dye laser centered at 852 nm as a pump and the fundamental 1064-nm radiation of the Nd:YAG as Stokes laser. The third harmonic is used as CARS probe and RS laser. The experimentally most elegant scheme replaces the third harmonic in the above scheme by the second harmonic hence involving the smallest number of optical components in the setup.

  8. All-solid-state parametric Raman anti-Stokes laser at 508 nm.

    PubMed

    Mildren, R P; Coutts, D W; Spence, D J

    2009-01-19

    We report a parametric anti-Stokes Raman laser using potassium gadolinium tungstate, generating output chiefly at the first anti-Stokes at 508 nm. The compact 4.5 cm long device is pumped by a Q-switched 532 nm laser and uses an off-axis Stokes resonator to provide non-collinear phase matching between the pump and the generated Stokes and anti-Stokes fields. Anti-Stokes output energies up 0.27 mJ were obtained at a conversion efficiency from the pump of 0.46%. Second- and third-order anti-Stokes lines at 486 nm and 465 nm were also observed.

  9. High-spectral-resolution coherent anti-Stokes Raman scattering with interferometrically detected broadband chirped pulses.

    PubMed

    Jones, Gareth W; Marks, Daniel L; Vinegoni, Claudio; Boppart, Stephen A

    2006-05-15

    To achieve high-spectral-resolution multiplex coherent anti-Stokes Raman scattering (CARS), one typically uses a narrowband pump pulse and a broadband Stokes pulse. This is to ensure a correspondence between anti-Stokes and vibrational frequencies. We obtain high-resolution CARS spectra of isopropanol, using a broadband chirped pump pulse and a broadband Stokes pulse, by detecting the anti-Stokes pulse with spectral interferometry. With the temporally resolved anti-Stokes signal, we can remove the chirp of the anti-Stokes pulse and restore high spectral resolution while also rejecting nonresonant scattering.

  10. Picosecond anti-Stokes generation in a photonic-crystal fiber for interferometric CARS microscopy.

    PubMed

    Andresen, Esben Ravn; Keiding, Søren Rud; Potma, Eric Olaf

    2006-08-07

    We generate tunable picosecond anti-Stokes pulses by four-wave mixing of two picosecond pump and Stokes pulse trains in a photonic-crystal fiber. The visible, spectrally narrow anti-Stokes pulses with shifts over 150 nm are generated without generating other spectral features. As a demonstration, we employ the generated anti-Stokes pulses as reference pulses in an interferometric coherent anti-Stokes Raman scattering imaging experiment showing that interpulse coherence among the pump, Stokes and anti-Stokes beams is retained.

  11. An electron beam polarimeter based on scattering from a windowless, polarized hydrogen gas target

    NASA Astrophysics Data System (ADS)

    Bernauer, Jan; Milner, Richard

    2013-11-01

    Here we present the idea to develop a precision polarimeter for low energy, intense polarized electron beams using a windowless polarized hydrogen gas cell fed by an atomic beam source. This technique would use proven technology used successfully in both the electron scattering experiments: HERMES with 27 GeV electron and positron beams at DESY, and BLAST with 850 MeV electron beams at MIT-Bates. At 100 MeV beam energy, both spin-dependent Mo/ller and elastic electron-proton scattering processes have a high cross section and sizable spin asymmetries. The concept is described and estimates for realistic rates for elastic electron-proton scattering and Mo/ller scattering are presented. A number of important issues which affect the ultimate systematic uncertainty are identified.

  12. An electron beam polarimeter based on scattering from a windowless, polarized hydrogen gas target

    SciTech Connect

    Bernauer, Jan; Milner, Richard

    2013-11-07

    Here we present the idea to develop a precision polarimeter for low energy, intense polarized electron beams using a windowless polarized hydrogen gas cell fed by an atomic beam source. This technique would use proven technology used successfully in both the electron scattering experiments: HERMES with 27 GeV electron and positron beams at DESY, and BLAST with 850 MeV electron beams at MIT-Bates. At 100 MeV beam energy, both spin-dependent Mo/ller and elastic electron-proton scattering processes have a high cross section and sizable spin asymmetries. The concept is described and estimates for realistic rates for elastic electron-proton scattering and Mo/ller scattering are presented. A number of important issues which affect the ultimate systematic uncertainty are identified.

  13. Ultraviolet spectrometer and polarimeter (UVSP) software development and hardware tests for the solar maximum mission

    NASA Technical Reports Server (NTRS)

    Bruner, M. E.; Haisch, B. M.

    1986-01-01

    The Ultraviolet Spectrometer/Polarimeter Instrument (UVSP) for the Solar Maximum Mission (SMM) was based on the re-use of the engineering model of the high resolution ultraviolet spectrometer developed for the OSO-8 mission. Lockheed assumed four distinct responsibilities in the UVSP program: technical evaluation of the OSO-8 engineering model; technical consulting on the electronic, optical, and mechanical modifications to the OSO-8 engineering model hardware; design and development of the UVSP software system; and scientific participation in the operations and analysis phase of the mission. Lockheed also provided technical consulting and assistance with instrument hardware performance anomalies encountered during the post launch operation of the SMM observatory. An index to the quarterly reports delivered under the contract are contained, and serves as a useful capsule history of the program activity.

  14. Faraday-effect polarimeter diagnostic for internal magnetic field fluctuation measurements in DIII-D

    NASA Astrophysics Data System (ADS)

    Chen, J.; Ding, W. X.; Brower, D. L.; Finkenthal, D.; Muscatello, C.; Taussig, D.; Boivin, R.

    2016-11-01

    Motivated by the need to measure fast equilibrium temporal dynamics, non-axisymmetric structures, and core magnetic fluctuations (coherent and broadband), a three-chord Faraday-effect polarimeter-interferometer system with fast time response and high phase resolution has recently been installed on the DIII-D tokamak. A novel detection scheme utilizing two probe beams and two detectors for each chord results in reduced phase noise and increased time response [δb ˜ 1G with up to 3 MHz bandwidth]. First measurement results were obtained during the recent DIII-D experimental campaign. Simultaneous Faraday and density measurements have been successfully demonstrated and high-frequency, up to 100 kHz, Faraday-effect perturbations have been observed. Preliminary comparisons with EFIT are used to validate diagnostic performance. Principle of the diagnostic and first experimental results is presented.

  15. Faraday-effect polarimeter diagnostic for internal magnetic field fluctuation measurements in DIII-D.

    PubMed

    Chen, J; Ding, W X; Brower, D L; Finkenthal, D; Muscatello, C; Taussig, D; Boivin, R

    2016-11-01

    Motivated by the need to measure fast equilibrium temporal dynamics, non-axisymmetric structures, and core magnetic fluctuations (coherent and broadband), a three-chord Faraday-effect polarimeter-interferometer system with fast time response and high phase resolution has recently been installed on the DIII-D tokamak. A novel detection scheme utilizing two probe beams and two detectors for each chord results in reduced phase noise and increased time response [δb ∼ 1G with up to 3 MHz bandwidth]. First measurement results were obtained during the recent DIII-D experimental campaign. Simultaneous Faraday and density measurements have been successfully demonstrated and high-frequency, up to 100 kHz, Faraday-effect perturbations have been observed. Preliminary comparisons with EFIT are used to validate diagnostic performance. Principle of the diagnostic and first experimental results is presented.

  16. Millipol, a millimeter/submillimeter wavelength polarimeter - Instrument, operation, and calibration

    NASA Technical Reports Server (NTRS)

    Clemens, Dan P.; Kane, Brian D.; Leach, Robert W.; Barvainis, Richard

    1990-01-01

    An instrument capable of measuring the polarization characteristics of weakly polarized, cold dust at millimeter and submillimeter wavelengths is presented in detail. The operation and calibration of this polarimeter at a wavelength of 1300 microns, configured for the NRAO 12-meter telescope, are discussed. Deep observations of Jupiter using this instrument revealed a main-beam instrumental polarization at, or below, the 0.2 percent level. Lunar limb observations revealed a sidelobe polarization sensitivity, in the range 0.25 percent - 1.0 percent. Further, through these efforts the nonthermal polarized flux from Jupiter at a level of about 0.04 percent of the thermal flux has been detected. Astronomical polarization measurements to 0.03 percent are possible, limited by the uncertainties in the instrumental polarization. This instrument has been primarily employed to measure and map magnetic-field directions in the very optically opaque cores of massive molecular clouds.

  17. Faraday-effect polarimeter-interferometer system for current density measurement on EAST

    NASA Astrophysics Data System (ADS)

    Liu, H. Q.; Jie, Y. X.; Ding, W. X.; Brower, D. L.; Zou, Z. Y.; Li, W. M.; Wang, Z. X.; Qian, J. P.; Yang, Y.; Zeng, L.; Lan, T.; Wei, X. C.; Li, G. S.; Hu, L. Q.; Wan, B. N.

    2014-11-01

    A multichannel far-infrared laser-based POlarimeter-INTerferometer (POINT) system utilizing the three-wave technique is under development for current density and electron density profile measurements in the EAST tokamak. Novel molybdenum retro-reflectors are mounted in the inside wall for the double-pass optical arrangement. A Digital Phase Detector with 250 kHz bandwidth, which will provide real-time Faraday rotation angle and density phase shift output, have been developed for use on the POINT system. Initial calibration indicates the electron line-integrated density resolution is less than 5 × 1016 m-2 (˜2°), and the Faraday rotation angle rms phase noise is <0.1°.

  18. A tracking polarimeter for measuring solar and ionospheric Faraday rotation of signals from deep space probes

    NASA Technical Reports Server (NTRS)

    Ohlson, J. E.; Levy, G. S.; Stelzried, C. T.

    1974-01-01

    A tracking polarimeter implemented on the 64-m NASA/JPL paraboloid antenna at Goldstone, Calif., is described. Its performance is analyzed and compared with measurements. The system was developed to measure Faraday rotation in the solar corona of the telemetry carrier from the Pioneer VI spacecraft as it was occulted by the sun. It also measures rotation in the earth's ionosphere and is an accurate method of determining spacecraft orientation. The new feature of this system is its use of a pair of quarter-wave plates to allow the synthesis of a rotating feed system, while requiring the rotation of only a single section of waveguide. Since the polarization sensing is done at RF and the receiver operates essentially as a null detector, the system's accuracy is superior to other polarization tracking schemes. In addition, the antenna size and maser preamplifier provide unsurpassed sensitivity. The associated instrumentation used in the Pioneer VI experiment is also described.

  19. Characterization of a high-temperature superconducting bearing for use in a cosmic microwave background polarimeter

    NASA Astrophysics Data System (ADS)

    Hull, John R.; Hanany, Shaul; Matsumura, Tomotake; Johnson, Bradley; Jones, Terry

    2005-02-01

    We have previously presented a design for a cosmic microwave background (CMB) polarimeter in which a cryogenically cooled half-wave plate rotates by means of a high-temperature superconducting (HTS) bearing. Here, a prototype bearing, consisting of a commercially available ring-shaped permanent magnet and an array of YBCO bulk HTS material, has been constructed. We measured its coefficient of friction and vibrational property as a function of several parameters, including temperature between 15 and 83 K, rotation frequency between 0.3 and 3.5 Hz, levitation distance between 6 and 10 mm and ambient pressure of {\\sim }10^{- 7} Torr. We concluded that the low rotational drag of the HTS bearing would allow rotations for long periods with minimal input power and negligible wear and tear, thus making this technology suitable for a future satellite mission.

  20. Design and Tests of the Hard X-Ray Polarimeter X-Calibur

    NASA Technical Reports Server (NTRS)

    Beilicke, M.; Baring, M. G.; Barthelmy, S.; Binns, W. R.; Buckley, J.; Cowsik, R.; Dowkontt, P.; Garson, A.; Guo, Q.; Haba, Y.; Israel, M. H.; Kunieda, H.; Lee, K.; Matsumoto, H.; Miyazawa, T.; Okajima, T.; Schnittman, J.; Tamura, K.; Tueller, J.; Krawczynski, H.

    2012-01-01

    X-ray polarimetry promises to give qualitatively new information about high-energy astrophysical sources, such as binary black hole systems, micro-quasars, active galactic nuclei, and gamma-ray bursts. We designed, built and tested a hard X-ray polarimeter X-Calibur to be used in the focal plane of the InFOC(mu)S grazing incidence hard X-ray telescope. X-Calibur combines a low-Z Compton scatterer with a CZT detector assembly to measure the polarization of 10 - 80 keY X-rays making use of the fact that polarized photons Compton scatter preferentially perpendicular to the electric field orientation. X-Calibur achieves a high detection efficiency of order unity.

  1. Far-forward collective scattering measurements by FIR polarimeter-interferometer on J-TEXT tokamak

    NASA Astrophysics Data System (ADS)

    Shi, P.; Chen, J.; Gao, L.; Liu, Y.; Liu, H.; Zhou, Y. N.; Zhuang, G.

    2016-11-01

    The multi-channel three-wave polarimeter-interferometer system on J-TEXT tokamak has been exploited to measure far-forward collective scattering from electron density fluctuations. The diagnostic utilizes far infrared lasers operated at 432 μm with 17-channel vertical chords (3 cm chord spacing), covering the entire cross section of plasma. Scattering laser power is measured using a high-sensitivity Schottky planar diode mixer which can also detect polarimetric and interferometric phase simultaneously. The system provides a line-integrated measurement of density fluctuations with maximum measurable wave number: k⊥max ≤ 2 cm-1 and time response up to 350 kHz. Feasibility of the diagnostic has been tested, showing higher sensitivity to detect fluctuation than interferometric measurement. Capability of providing spatial-resolved information of fluctuation has also been demonstrated in preliminary experimental applications.

  2. Far-forward collective scattering measurements by FIR polarimeter-interferometer on J-TEXT tokamak.

    PubMed

    Shi, P; Chen, J; Gao, L; Liu, Y; Liu, H; Zhou, Y N; Zhuang, G

    2016-11-01

    The multi-channel three-wave polarimeter-interferometer system on J-TEXT tokamak has been exploited to measure far-forward collective scattering from electron density fluctuations. The diagnostic utilizes far infrared lasers operated at 432 μm with 17-channel vertical chords (3 cm chord spacing), covering the entire cross section of plasma. Scattering laser power is measured using a high-sensitivity Schottky planar diode mixer which can also detect polarimetric and interferometric phase simultaneously. The system provides a line-integrated measurement of density fluctuations with maximum measurable wave number: k⊥max ≤ 2 cm(-1) and time response up to 350 kHz. Feasibility of the diagnostic has been tested, showing higher sensitivity to detect fluctuation than interferometric measurement. Capability of providing spatial-resolved information of fluctuation has also been demonstrated in preliminary experimental applications.

  3. EAST equilibrium current profile reconstruction using polarimeter-interferometer internal measurement constraints

    NASA Astrophysics Data System (ADS)

    Qian, J. P.; Lao, L. L.; Liu, H. Q.; Ding, W. X.; Zeng, L.; Luo, Z. P.; Ren, Q. L.; Huang, Y.; Huang, J.; Brower, D. L.; Hanada, K.; Chen, D. L.; Sun, Y. W.; Shen, B.; Gong, X. Z.; Xiao, B. J.; Wan, B. N.

    2017-03-01

    The first equilibrium reconstruction of EAST current-density profile based on internal Faraday rotation measurements provided by the POlarimeter-INTerferometer (POINT) diagnostic is demonstrated using the EFIT equilibrium reconstruction code. EFIT incorporates 11 simultaneous line-integrated density and Faraday effect measurements from POINT to self-consistently reconstruct the equilibrium toroidal current density profile using a Faraday rotation reconstruction algorithm. It is shown that the POINT measurements can be applied to improve the accuracy of core plasma current density and q profile on EAST. Comparisons of magnetic surfaces and the q profile reconstructed using external magnetic data against those using magnetic and POINT data are presented. Equilibrium reconstructions using POINT data are found to be consistent with sawtooth phenomena. The sensitivity of equilibrium reconstruction to POINT measurements indicates Faraday rotation provides important constraints for determining the current profile.

  4. Derivation of Cumulus Cloud Dimensions and Shape from the Airborne Measurements by the Research Scanning Polarimeter

    NASA Technical Reports Server (NTRS)

    Alexandrov, Mikhail D.; Cairns, Brian; Emde, Claudia; Ackerman, Andrew S.; Ottaviani, Matteo; Wasilewski, Andrzej P.

    2016-01-01

    The Research Scanning Polarimeter (RSP) is an airborne instrument, whose measurements have been extensively used for retrievals of microphysical properties of clouds. In this study we show that for cumulus clouds the information content of the RSP data can be extended by adding the macroscopic parameters of the cloud, such as its geometric shape, dimensions, and height above the ground. This extension is possible by virtue of the high angular resolution and high frequency of the RSP measurements, which allow for geometric constraint of the cloud's 2D cross section between a number of tangent lines of view. The retrieval method is tested on realistic 3D radiative transfer simulations and applied to actual RSP data.

  5. Ultraviolet spectropolarimetry of the Be star PP Carinae with the Wisconsin Ultraviolet Photo-Polarimeter Experiment

    NASA Technical Reports Server (NTRS)

    Bjorkman, K. S.; Meade, M. R.; Nordsieck, K. H.; Anderson, C. M.; Babler, B. L.; Clayton, G. C.; Code, A. D.; Magalhaes, A. M.; Schulte-Ladbeck, R. E.; Taylor, M.

    1993-01-01

    We present the first ultraviolet spectropolarimetric observations of the Be star PP Car, obtained with the Wisconsin Ultraviolet Photo-Polarimeter Experiment (WUPPE) aboard the Astro 1 mission. Usable polarization data were obtained from 1400 to 2330 A, along with a good spectrum from 1400 to 3200 A. These data show a lower polarization shortward of the Balmer jump than had been predicted by standard models, and a broad UV polarization dip around 1900 A is seen. These results are in agreement with those found from the WUPPE observations of two other Be stars, Xi Tau and Pi Aqr, which were published earlier. All these observations are an important probe of the Be circumstellar envelopes and demonstrate the need for the inclusion of metal-line effects in circumstellar disk models of Be star UV polarization.

  6. First ultraviolet spectropolarimetry of Be stars from the Wisconsin Ultraviolet Photo-Polarimeter Experiment

    NASA Technical Reports Server (NTRS)

    Bjorkman, K. S.; Nordsieck, K. H.; Code, A. D.; Anderson, C. M.; Babler, B. L.; Clayton, G. C.; Magalhaes, A. M.; Meade, M. R.; Nook, M. A.; Schulte-Ladbeck, R. E.

    1991-01-01

    The first UV spectropolarimetric observations of Be stars are presented. They were obtained with the Wisconsin Ultraviolet Photo-Polarimeter Experiment (WUPPE) aboard the Astro-1 mission. WUPPE data on the Be stars Zeta Tau and Pi Aqr, along with near-simultaneous optical data obtained at the Pine Bluff Observatory (PBO). Combined WUPPE and PBO data give polarization as a function of wavelength across a very broad spectral region, from 1400 to 7600 A. Existing Be star models predicted increasing polarization toward shorter wavelengths in the UV, but this is not supported by the WUPPE observations. Instead, the observations show a constant or slightly declining continuum polarization shortward of the Balmer jump, and broad UV polarization dips around 1700 and 1900 A, which may be a result of Fe-line-attenuation effects on the polarized flux. Supporting evidence for this conclusion comes from the optical data, in which decreases in polarization across Fe II lines in Zeta Tau were discovered.

  7. Faraday-effect polarimeter-interferometer system for current density measurement on EAST.

    PubMed

    Liu, H Q; Jie, Y X; Ding, W X; Brower, D L; Zou, Z Y; Li, W M; Wang, Z X; Qian, J P; Yang, Y; Zeng, L; Lan, T; Wei, X C; Li, G S; Hu, L Q; Wan, B N

    2014-11-01

    A multichannel far-infrared laser-based POlarimeter-INTerferometer (POINT) system utilizing the three-wave technique is under development for current density and electron density profile measurements in the EAST tokamak. Novel molybdenum retro-reflectors are mounted in the inside wall for the double-pass optical arrangement. A Digital Phase Detector with 250 kHz bandwidth, which will provide real-time Faraday rotation angle and density phase shift output, have been developed for use on the POINT system. Initial calibration indicates the electron line-integrated density resolution is less than 5 × 10(16) m(-2) (∼2°), and the Faraday rotation angle rms phase noise is <0.1°.

  8. Design and Tests of the Hard X-Ray Polarimeter X-Calibur

    NASA Technical Reports Server (NTRS)

    Beilicke, M.; Binns, W. R.; Buckley, J.; Cowsik, R.; Dowkontt, P.; Garson, A.; Guo, Q.; Israel, M. H.; Lee, K.; Krawczynski, H.; Baring, M. G.; Barthelmy, S.; Okajima, T.; Schnittman, J.; Tueller, J.; Haba, Y.; Kunieda, H.; Matsumoto, H.; Miyazawa, T.; Tamura, K.

    2011-01-01

    X-ray polarimetry promises to give new information about high-energy astrophysical sources, such as binary black hole systems, micro-quasars, active galactic nuclei, and gamma-ray bursts. We designed, built and tested a hard X-ray polarimeter X-Calibur to be used in the focal plane of the InFOC(mu)S grazing incidence hard X-ray telescope. X-Calibur combines a low-Z Compton scatterer with a CZT detector assembly to measure the polarization of 10-80 keV X-rays making use of the fact that polarized photons Compton scatter preferentially perpendicular to the electric field orientation. X-Calibur achieves a high detection efficiency of order unity.

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

    SciTech Connect

    Kortright, J.B.; Smith, N.V.; Denlinger, J.D.

    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.

  10. A Spin-Light Polarimeter for Multi-GeV Longitudinally Polarized Electron Beams

    SciTech Connect

    Mohanmurthy, Prajwal; Dutta, Dipangkar

    2014-02-01

    The physics program at the upgraded Jefferson Lab (JLab) and the physics program envisioned for the proposed electron-ion collider (EIC) include large efforts to search for interactions beyond the Standard Model (SM) using parity violation in electroweak interactions. These experiments require precision electron polarimetry with an uncertainty of < 0.5 %. The spin dependent Synchrotron radiation, called "spin-light," can be used to monitor the electron beam polarization. In this article we develop a conceptual design for a "spin-light" polarimeter that can be used at a high intensity, multi-GeV electron accelerator. We have also built a Geant4 based simulation for a prototype device and report some of the results from these simulations.

  11. Research Scanning Polarimeter (RSP): Retrievals from PODEX and SEAC4RS

    NASA Technical Reports Server (NTRS)

    Cairns, Brian; van Diedenhoven, Bastiaan; Alexandrov, Mikhail; Chowdhary, Jacek; Wasilewski, Andrzej P.; Mishchenko, Michael

    2014-01-01

    We illustrate our methods on examples from the recent NASA's field campaigns POlarimeter Definition EXperiment (PODEX, based in Palmdale, California, January - February 2013) and Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS, based in Houston, Texas in August - September 2013). During these campaigns the RSP was onboard the NASA's long-range high-altitude ER-2 aircraft together with an array of other remote sensing instrumentation. Correlative sampling measurements from another aircraft were also available. The data obtained during these campaigns provides an excellent opportunity to study cloud properties in variety of locations and atmospheric conditions. We present examples of boundary layer cumulus and stratocumulus clouds, liquid altostratus clouds, and fogs. In the latter two cases the droplet size distribution derived from RFT analysis exhibited multiple modes corresponding to different cloud layers, as supported by the correlative lidar atmospheric profiles.

  12. Faraday-effect polarimeter-interferometer system for current density measurement on EAST

    SciTech Connect

    Liu, H. Q.; Jie, Y. X. Zou, Z. Y.; Li, W. M.; Wang, Z. X.; Qian, J. P.; Yang, Y.; Zeng, L.; Wei, X. C.; Hu, L. Q.; Wan, B. N.; Ding, W. X.; Brower, D. L.; Lan, T.; Li, G. S.

    2014-11-15

    A multichannel far-infrared laser-based POlarimeter-INTerferometer (POINT) system utilizing the three-wave technique is under development for current density and electron density profile measurements in the EAST tokamak. Novel molybdenum retro-reflectors are mounted in the inside wall for the double-pass optical arrangement. A Digital Phase Detector with 250 kHz bandwidth, which will provide real-time Faraday rotation angle and density phase shift output, have been developed for use on the POINT system. Initial calibration indicates the electron line-integrated density resolution is less than 5 × 10{sup 16} m{sup −2} (∼2°), and the Faraday rotation angle rms phase noise is <0.1°.

  13. The Gamma-Ray Imager/Polarimeter for Solar flares (GRIPS)

    NASA Astrophysics Data System (ADS)

    Shih, Albert Y.; Lin, Robert P.; Hurford, Gordon J.; Duncan, Nicole A.; Saint-Hilaire, Pascal; Bain, Hazel M.; Boggs, Steven E.; Zoglauer, Andreas C.; Smith, David M.; Tajima, Hiroyasu; Amman, Mark S.; Takahashi, Tadayuki

    2012-09-01

    The balloon-borne Gamma-Ray Imager/Polarimeter for Solar flares (GRIPS) instrument will provide a near-optimal combination of high-resolution imaging, spectroscopy, and polarimetry of solar-flare gamma-ray/hard X-ray emissions from ~20 keV to >~10 MeV. GRIPS will address questions raised by recent solar flare observations regarding particle acceleration and energy release, such as: What causes the spatial separation between energetic electrons producing hard X-rays and energetic ions producing gamma-ray lines? How anisotropic are the relativistic electrons, and why can they dominate in the corona? How do the compositions of accelerated and ambient material vary with space and time, and why? The spectrometer/polarimeter consists of sixteen 3D position-sensitive germanium detectors (3D-GeDs), where each energy deposition is individually recorded with an energy resolution of a few keV FWHM and a spatial resolution of <0.1 mm3. Imaging is accomplished by a single multi-pitch rotating modulator (MPRM), a 2.5-cm thick tungstenalloy slit/slat grid with pitches that range quasi-continuously from 1 to 13 mm. The MPRM is situated 8 meters from the spectrometer to provide excellent image quality and unparalleled angular resolution at gamma-ray energies (12.5 arcsec FWHM), sufficient to separate 2.2 MeV footpoint sources for almost all flares. Polarimetry is accomplished by analyzing the anisotropy of reconstructed Compton scattering in the 3D-GeDs (i.e., as an active scatterer), with an estimated minimum detectable polarization of a few percent at 150-650 keV in an X-class flare. GRIPS is scheduled for a continental-US engineering test flight in fall 2013, followed by long or ultra-long duration balloon flights in Antarctica.

  14. The Gamma-Ray Imager/Polarimeter for Solar Flares (GRIPS)

    NASA Astrophysics Data System (ADS)

    Shih, A. Y.; Lin, R. P.; Hurford, G. J.; Boggs, S. E.; Zoglauer, A. C.; Wunderer, C. B.; Sample, J. G.; Turin, P.; McBride, S.; Smith, D. M.; Tajima, H.; Luke, P. N.; Amman, M. S.

    2008-12-01

    The new balloon-borne Gamma-Ray Imager/Polarimeter for Solar flares (GRIPS) instrument will provide a near-optimal combination of high-resolution imaging, spectroscopy, and polarimetry of solar-flare gamma-ray/hard X-ray emissions from ~20 keV to >~10 MeV. The spectrometer/polarimeter consists of sixteen 3D position-sensitive germanium detectors (3D-GeDs), where each energy deposition is individually recorded with an energy resolution of a few keV FWHM and a spatial resolution to within <0.1 mm3. Imaging is accomplished by a single multi-pitch rotating modulator (MPRM), a 2-cm thick tungsten grid with pitches that range quasi-continuously from 1 to 13 mm. With the MPRM situated 8 meters from the spectrometer, this instrument will provide excellent image quality and unparalleled angular resolution at gamma-ray energies (12.5 arcsec FWHM), sufficient to separate the 2.2 MeV footpoint sources for almost all flares. Polarimetry is accomplished by analyzing the anisotropy of reconstructed Compton scattering in the 3D-GeDs (i.e. as an active scatterer), with an estimated minimum detectable polarization of a few percent at 150--650 keV in an X-class flare. GRIPS will address questions relevant to particle acceleration and energy release that have been raised by recent solar flare observations, such as: What causes the spatial separation between energetic electron producing hard X-rays and energetic ions producing gamma-ray lines? How anisotropic are the accelerated electrons, and why do relativistic electron dominate in the corona? How does the composition of accelerated and ambient material vary with space and time, and why?

  15. The ZIMPOL high contrast imaging polarimeter for SPHERE: polarimetric high contrast commissioning results

    NASA Astrophysics Data System (ADS)

    Roelfsema, Ronald; Bazzon, Andreas; Schmid, Hans Martin; Pragt, Johan; Govaert, Alain; Gisler, Daniel; Dominik, Carsten; Baruffolo, Andrea; Beuzit, Jean-Luc; Costille, Anne; Dohlen, Kjetil; Downing, Mark; Elswijk, Eddy; de Haan, Menno; Hubin, Norbert; Kasper, Markus; Keller, Christoph; Lizon, Jean-Louis; Mouillet, David; Pavlov, Alexey; Puget, Pascal; Salasnich, Bernardo; Sauvage, Jean-Francois; Wildi, Francois

    2016-07-01

    SPHERE (Spectro-Polarimetric High-contrast Exoplanet Research) is a second generation VLT instrument aimed at the direct detection of exo-planets. It has received its first light in May 2014. ZIMPOL (Zurich Imaging Polarimeter) is the imaging polarimeter subsystem of the SPHERE instrument. It's capable of both high accuracy and high sensitivity polarimetry but can also be used as a classical imager. It is located behind an extreme AO system and a stellar coronagraph. ZIMPOL operates at visible wavelengths which is best suited to detect the very faint reflected and hence polarized visible light from extra solar planets. During the SPHERE fourth commissioning period (October 2014) we have made deep coronagraphic observations of the bright star alpha Gru (mR = 1.75) to assess the high contrast polarimetric performance of SPHERE-ZIMPOL. We have integrated on the target for a total time of about 45 minutes during the meridian transit in the Very Broad Band filter (600 - 900 nm) with a classical Lyot coronagraph with 3 λ/D radius focal mask. We reduce the data by a combination of Polarized Background subtraction, Polarimetric Differential Imaging (PDI) and Angular Differential Imaging (ADI). We reach contrasts of 10-6 and 10-7 at a radial distances of respectively 7 and 14 lambda/D from the PSF core. At these radial distances we are respectively a factor of 10 and 2 above the photon noise limit. We discuss our results by considering the temporal and spatial speckle behavior close to the PSF core in combination with low order polarimetric aberrations.

  16. BLAST-TNG: A Next Generation Balloon-borne Large Aperture Submillimeter Polarimeter

    NASA Astrophysics Data System (ADS)

    Fissel, Laura M.; Ade, Peter; Angilè, Francesco E.; Campbell Ashton, Peter; Austermann, Jason Edward; Billings, Tashalee; Che, George; Cho, Hsiao-Mei; Cunningham, Maria R.; Davis, Kristina; Devlin, Mark J.; Dicker, Simon; Dober, Bradley; Fukui, Yasuo; Galitzki, Nicholas; gao, jiansong; Gordon, Sam; Groppi, Christopher E.; Hillbrand, Seth; Hilton, Gene; Hubmayr, Hannes; Irwin, Kent; Jones, Paul; Klein, Jeffrey; li, dale; Li, Zhi-Yun; lourie, nathan; Lowe, Ian; Mani, Hamdi; Martin, Peter G.; Mauskopf, Philip; McKenney, Christopher; Nati, Federico; Novak, Giles; Pascale, Enzo; pisano, giampaolo; Pereira Santos, Fábio; Scott, Douglas; Sinclair, Adrian; Diego Diego Soler, Juan; tucker, carole; Underhill, Matthew; Vissers, Michael; Williams, Paul

    2017-01-01

    Measurements of polarized thermal dust emission can be used to map magnetic fields in the interstellar medium. Recently, BLASTPol, the Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry, has published the most detailed map ever made of a giant molecular cloud forming high-mass stars. I will present an overview of The Next Generation BLAST polarimeter (BLAST-TNG), the successor telescope to BLASTPol, which maps linearly polarized dust emission at 250, 350 and 500 μm. BLAST-TNG utilizes a 2.5-meter carbon-fiber primary mirror that illuminates focal plane arrays containing over 3,000 microwave kinetic inductance detectors. This new polarimeter has an order of magnitude increase in mapping speed and resolution compared to BLASTPol and we expect to make over 500,000 measurements of magnetic field orientation per flight. BLAST-TNG will have the sensitivity to map entire molecular cloud complexes as well as regions of diffuse high Galactic latitude dust. It also has the resolution (FWHM = 25’’ at 250 μm) necessary to trace magnetic fields in prestellar cores and dense filaments. BLAST-TNG will thus provide a crucial link between the low resolution Planck all-sky maps and the detailed but narrow field of view polarimetry capabilities of ALMA. For our first Antarctic flight in December 2017 we are putting out a call for shared-risk proposals to fill 25% of the available science time. In addition, BLAST-TNG data will be publicly released within a year of the publication of our first look papers, leaving a large legacy data set for the study of the role played by magnetic fields in the star formation process and the properties of interstellar dust.

  17. Polarimeter Arrays with Comprehensive Frequency Coverage for the Next Generation of Precision Microwave Background Experiments

    NASA Astrophysics Data System (ADS)

    Austermann, Jason Edward; Beall, James; Becker, Dan; Cho, Hsiao-Mei; Duff, Shannon; gao, jiansong; Hilton, Gene; Hubmayr, Johannes; Irwin, Kent; li, dale; McKenney, Christopher; Ullom, Joel; van lanen, jeffrey; Vissers, Michael

    2016-06-01

    Spectral resolution at (sub-)millimeter wavelengths is now understood to be crucially important in precision measurements of the cosmic microwave background (CMB). Recent results from the Planck and BICEP/KECK experiments have established that measurements of the CMB polarization signal is limited, in part, by polarized foreground emission. In particular, polarized emission from galactic dust has been found to dominate and obscure potential signals of cosmic inflation, even in regions of the sky specifically identified as having relatively low galactic emission. Current and future experiments aim to address foreground contamination by conducting high-sensitivity observations with broad spectral coverage that will allow for differentiation within the measured signal between foreground sources of polarization and that of the CMB, which each have distinct spectral characteristics. To efficiently achieve these goals within a limited focal plane area, NIST-Boulder has developed multi-band TES-based polarimeters that simultaneously measure multiple spectral bands in each of two orthogonal polarizations. This acts to both increase pixel sensitivity through an increased total bandwidth, as well as providing broad spectral information for differentiation of emission sources. Here, we describe recent achievements and ongoing efforts at NIST-Boulder in the development of millimeter and sub-millimeter detector and focal plane technologies for future experiments, including the stage-IV CMB experiment, CMB-S4. NIST-Boulder provides critical cryogenic components to a large number of current and in-development CMB experiments. Recent milestones include the fielding of the first broadband multi-chroic mm-wave polarimeters in the ACTPol experiment, multi-band array fabrication on large-format 150 mm wafers, and development of matching 150 mm silicon platelet feedhorn arrays. We also review several related development efforts in detector, optical coupling, and readout technologies

  18. The Gamma-Ray Imager/Polarimeter for Solar Flares (GRIPS)

    NASA Technical Reports Server (NTRS)

    Shih, Albert Y.; Lin, Robert P.; Hurford, Gordon J.; Duncan, Nicole A.; Saint-Hilaire, Pascal; Bain, Hazel M.; Boggs, Steven E.; Zoglauer, Andreas C.; Smith, David M.; Tajima, Hiroyasu; Amman, Mark S.; Takahashi, Tadayuki

    2012-01-01

    The balloon-borne Gamma-Ray Imager/Polarimeter for Solar flares (GRIPS) instrument will provide a near-optimal combination of high-resolution imaging, spectroscopy, and polarimetry of solar-flare gamma-ray/hard X-ray emissions from approximately 20 keV to greater than approximately 10 MeV. GRIPS will address questions raised by recent solar flare observations regarding particle acceleration and energy release, such as: What causes the spatial separation between energetic electrons producing hard X-rays and energetic ions producing gamma-ray lines? How anisotropic are the relativistic electrons, and why can they dominate in the corona? How do the compositions of accelerated and ambient material vary with space and time, and why? The spectrometer/polarimeter consists of sixteen 3D position-sensitive germanium detectors (3D-GeDs), where each energy deposition is individually recorded with an energy resolution of a few keV FWHM and a spatial resolution of less than 0.1 cubic millimeter. Imaging is accomplished by a single multi-pitch rotating modulator (MPRM), a 2.5-centimeter thick tungsten alloy slit/slat grid with pitches that range quasi-continuously from 1 to 13 millimeters. The MPRM is situated 8 meters from the spectrometer to provide excellent image quality and unparalleled angular resolution at gamma-ray energies (12.5 arcsec FWHM), sufficient to separate 2.2 MeV footpoint sources for almost all flares. Polarimetry is accomplished by analyzing the anisotropy of reconstructed Compton scattering in the 3D-GeDs (i.e., as an active scatterer), with an estimated minimum detectable polarization of a few percent at 150-650 keV in an X-class flare. GRIPS is scheduled for a continental-US engineering test flight in fall 2013, followed by long or ultra-long duration balloon flights in Antarctica.

  19. A Study of Planetary System Formation and Evolution Using a Dual Channel Adaptive Optics Imaging Polarimeter

    NASA Technical Reports Server (NTRS)

    Potter, Daniel E.

    2003-01-01

    The award I received from the Graduate Student Research Program in 2001, and the renewal award in 2002, supported the gathering and processing of my thesis data, and the presentation of my scientific results at astronomy conferences. Ultimately, this led to a successful defense of my PhD thesis. In the thesis work, I built, calibrated, and observed with the first dual imaging polarimeter ever used in series with a high order adaptive optics system and on an 8 meter class telescope. The instrument was arguably the most sensitive instrument for the high-contrast detection of the scattered light from circumstellar disks. The success of the instrument has provided the impetus for the construction of several similar simultaneous adaptive optics imaging polarimeters. In the course of the observations, a number of circumstellar disks were resolved for the first time in their scattered light, such as the disk around the classical T-tauri stars, LkCa 15 and LkHa 262. A sample of 24 young, nearby, solar-analog stars were observed with the instrument in search of the scattered light signature from debris disks around these stars. Although none of the stars revealed any obvious scattered light signatures, a meaningful limit was placed on the dust population around these stars. Also, a brown dwarf binary system was found to be a companion to one of the solar-analog stars observed, HD130948. A careful monitoring of the orbit of the binary brown dwarf will result in a dynamical mass determination of the objects, providing a valuable calibration of the physical models explaining brown dwarf evolution.

  20. Determination of electron beam polarization using electron detector in Compton polarimeter with less than 1% statistical and systematic uncertainty

    SciTech Connect

    Narayan, Amrendra

    2015-05-01

    The Q-weak experiment aims to measure the weak charge of proton with a precision of 4.2%. The proposed precision on weak charge required a 2.5% measurement of the parity violating asymmetry in elastic electron - proton scattering. Polarimetry was the largest experimental contribution to this uncertainty and a new Compton polarimeter was installed in Hall C at Jefferson Lab to make the goal achievable. In this polarimeter the electron beam collides with green laser light in a low gain Fabry-Perot Cavity; the scattered electrons are detected in 4 planes of a novel diamond micro strip detector while the back scattered photons are detected in lead tungstate crystals. This diamond micro-strip detector is the first such device to be used as a tracking detector in a nuclear and particle physics experiment. The diamond detectors are read out using custom built electronic modules that include a preamplifier, a pulse shaping amplifier and a discriminator for each detector micro-strip. We use field programmable gate array based general purpose logic modules for event selection and histogramming. Extensive Monte Carlo simulations and data acquisition simulations were performed to estimate the systematic uncertainties. Additionally, the Moller and Compton polarimeters were cross calibrated at low electron beam currents using a series of interleaved measurements. In this dissertation, we describe all the subsystems of the Compton polarimeter with emphasis on the electron detector. We focus on the FPGA based data acquisition system built by the author and the data analysis methods implemented by the author. The simulations of the data acquisition and the polarimeter that helped rigorously establish the systematic uncertainties of the polarimeter are also elaborated, resulting in the first sub 1% measurement of low energy (?1 GeV) electron beam polarization with a Compton electron detector. We have demonstrated that diamond based micro-strip detectors can be used for tracking in a

  1. Calibration of the 6302/6301 Stokes V line ratio in terms of the 5250/5247 ratio

    NASA Astrophysics Data System (ADS)

    Stenflo, J. O.; Demidov, M. L.; Bianda, M.; Ramelli, R.

    2013-08-01

    Four decades ago the Stokes V line ratio in the Fe i 5247.06 and 5250.22 Å lines was introduced as a powerful means of exploring the intrinsic field strengths at sub-pixel scales, which led to the discovery that most of the photospheric flux is in intermittent kG form. The "green" 5247-5250 line pair is unique because it allows the magnetic-field effects to be isolated from the thermodynamic effects. No other line pair with this property has since been identified. In recent years much of the magnetic-field diagnostics has been based on the "red" Fe i 6301.5 and 6302.5 Å line pair, since it was chosen in the design of the Hinode space observatory. Although thermodynamic effects severely contaminate the magnetic-field signatures for this line ratio, it is still possible to use it to extract information on intrinsic magnetic fields, but only after it has been "renormalized", since otherwise it produces fictitious, superstrong fields everywhere. In the present work we explore the joint behavior of these two line ratios to determine how the "contaminated" red line ratio can be translated into the corresponding green line ratio, which then allows for a direct interpretation in terms of intrinsic magnetic fields. Our observations are mainly based on recordings with the ZIMPOL-3 spectro-polarimeter at IRSOL in Locarno, Switzerland, complemented by data from the STOP telescope at the Sayan solar observatory (Irkutsk, Russia). The IRSOL observations are unique by allowing both the green and red line pairs to be recorded simultaneously on the same CCD sensor. We show how the line ratios depend on both the measured flux densities and on the heliocentric distance (the μ value on the solar disk), and finally derive the calibration function that enables the red line ratio to be translated to the green ratio for each μ value.

  2. Large size GEM for Super Bigbite Spectrometer (SBS) polarimeter for Hall A 12GeV program at JLab

    SciTech Connect

    Gnanvo, Kondo; Liyanage, Nilanga; Nelyubin, Vladimir; Saenboonruang, Kiadtisak; Sacher, Seth; Wojtsekhowski, Bogdan

    2015-05-01

    We report on the R&D effort in the design and construction of a large size GEM chamber for the Proton Polarimeter of the Super Bigbite Spectrometer (SBS) in Hall A at Thomas Jefferson National Laboratory (JLab). The SBS Polarimeter trackers consist of two sets of four large chambers of size 200 cm x 60 cm2. Each chamber is a vertical stack of four GEM modules with an active area of 60 cm x 50 cm. We have built and tested several GEM modules and we describe in this paper the design and construction of the final GEM as well as the preliminary results on performances from tests carried out in our detector lab and with test beams at (Fermilab).

  3. Large size GEM for Super Bigbite Spectrometer (SBS) polarimeter for Hall A 12GeV program at JLab

    DOE PAGES

    Gnanvo, Kondo; Liyanage, Nilanga; Nelyubin, Vladimir; ...

    2015-05-01

    We report on the R&D effort in the design and construction of a large size GEM chamber for the Proton Polarimeter of the Super Bigbite Spectrometer (SBS) in Hall A at Thomas Jefferson National Laboratory (JLab). The SBS Polarimeter trackers consist of two sets of four large chambers of size 200 cm x 60 cm2. Each chamber is a vertical stack of four GEM modules with an active area of 60 cm x 50 cm. We have built and tested several GEM modules and we describe in this paper the design and construction of the final GEM as well asmore » the preliminary results on performances from tests carried out in our detector lab and with test beams at (Fermilab).« less

  4. Design of a dispersion interferometer combined with a polarimeter to increase the electron density measurement reliability on ITER

    NASA Astrophysics Data System (ADS)

    Akiyama, T.; Sirinelli, A.; Watts, C.; Shigin, P.; Vayakis, G.; Walsh, M.

    2016-11-01

    A dispersion interferometer is a reliable density measurement system and is being designed as a complementary density diagnostic on ITER. The dispersion interferometer is inherently insensitive to mechanical vibrations, and a combined polarimeter with the same line of sight can correct fringe jump errors. A proof of the principle of the CO2 laser dispersion interferometer combined with the PEM polarimeter was recently conducted, where the phase shift and the polarization angle were successfully measured simultaneously. Standard deviations of the line-average density and the polarization angle measurements over 1 s are 9 × 1016 m-2 and 0.19°, respectively, with a time constant of 100 μs. Drifts of the zero point, which determine the resolution in steady-state operation, correspond to 0.25% and 1% of the phase shift and the Faraday rotation angle expected on ITER.

  5. Double-wedged Wollaston-type polarimeter design and integration to RTT150-TFOSC; initial tests, calibration, and characteristics

    NASA Astrophysics Data System (ADS)

    Helhel, S.; Khamitov, I.; Kahya, G.; Bayar, C.; Kaynar, S.; Gumerov, R.

    2015-10-01

    Photometric and spectroscopic observation capabilities of 1.5-m Russian-Turkish Telescope RTT150 has been broadened with the integration of presented polarimeter. The well-known double-wedged Wollaston-type dual-beam technique was preferred and applied to design and produce it. The designed polarimeter was integrated into the telescope detector TFOSC, and called TFOSC-WP. Its capabilities and limitations were attempted to be determined by a number of observation sets. Non-polarized and strongly polarized stars were observed to determine its limitations as well as its linearity. An instrumental intrinsic polarization was determined for the 1 × 5 arcmin field of view in equatorial coordinate system, the systematic error of polarization degree as 0.2 %, and position angle as 1.9∘. These limitations and capabilities are denoted as good enough to satisfy telescopes' present and future astrophysical space missions related to GAIA and SRG projects.

  6. Design of a dispersion interferometer combined with a polarimeter to increase the electron density measurement reliability on ITER.

    PubMed

    Akiyama, T; Sirinelli, A; Watts, C; Shigin, P; Vayakis, G; Walsh, M

    2016-11-01

    A dispersion interferometer is a reliable density measurement system and is being designed as a complementary density diagnostic on ITER. The dispersion interferometer is inherently insensitive to mechanical vibrations, and a combined polarimeter with the same line of sight can correct fringe jump errors. A proof of the principle of the CO2 laser dispersion interferometer combined with the PEM polarimeter was recently conducted, where the phase shift and the polarization angle were successfully measured simultaneously. Standard deviations of the line-average density and the polarization angle measurements over 1 s are 9 × 10(16) m(-2) and 0.19°, respectively, with a time constant of 100 μs. Drifts of the zero point, which determine the resolution in steady-state operation, correspond to 0.25% and 1% of the phase shift and the Faraday rotation angle expected on ITER.

  7. MAGNETIC FIELDS OF AN ACTIVE REGION FILAMENT FROM FULL STOKES ANALYSIS OF Si I 1082.7 nm AND He I 1083.0 nm

    SciTech Connect

    Xu, Z.; Liu, Y.

    2012-04-20

    Vector magnetic fields of an active region filament in the photosphere and upper chromosphere are obtained from spectro-polarimetric observations recorded with the Tenerife Infrared Polarimeter (TIP II) at the German Vacuum Tower Telescope. We apply Milne-Eddington inversions on full Stokes vectors of the photospheric Si I 1082.7 nm and the upper chromospheric He I triplet at 1083.0 nm to obtain the magnetic field vector and velocity maps in two atmosphere layers. We find that (1) a complete filament was already present in H{alpha} at the beginning of the TIP II data acquisition. Only a partially formed one, composed of multiple small threads, was present in He I. (2) The AR filament comprises two sections. One shows strong magnetic field intensities, about 600-800 G in the upper chromosphere and 800-1000 G in the photosphere. The other exhibits only comparatively weak magnetic field strengths in both layers. (3) The Stokes V signal is indicative of a dip in the magnetic field strength close to the chromospheric PIL. (4) In the chromosphere, consistent upflows are found along the PIL flanked by downflows. (5) The transversal magnetic field is nearly parallel to the PIL in the photosphere and inclined by 20 Degree-Sign -30 Degree-Sign in the chromosphere. (6) The chromospheric magnetic field around the filament is found to be in normal configuration, while the photospheric field presents a concave magnetic topology. The observations are consistent with the emergence of a flux rope with a subsequent formation of a filament.

  8. Note: Stability control of intermediate frequencies of a three laser far-infrared polarimeter-interferometer system.

    PubMed

    Yu, Jiang-Tao; Li, He-Ping; Nie, Qiu-Yue; Zou, Zhi-Yong; Liu, Hai-Qing; Bao, Cheng-Yu; Jie, Yin-Xian; Li, Zhan-Xian

    2016-12-01

    Stability of the intermediate frequency (IF) in the far-infrared polarimeter-interferometer diagnostic system is critically important for the long pulse discharge experiments on the EAST tokamak. In this note, a real-time remote/local IF stability control system is described. The measured plasma parameters, including the Faraday rotation angle, electron density, lower hybrid wave, and plasma current, are obtained with the aid of this newly developed IF stability control system.

  9. Note: Stability control of intermediate frequencies of a three laser far-infrared polarimeter-interferometer system

    NASA Astrophysics Data System (ADS)

    Yu, Jiang-Tao; Li, He-Ping; Nie, Qiu-Yue; Zou, Zhi-Yong; Liu, Hai-Qing; Bao, Cheng-Yu; Jie, Yin-Xian; Li, Zhan-Xian

    2016-12-01

    Stability of the intermediate frequency (IF) in the far-infrared polarimeter-interferometer diagnostic system is critically important for the long pulse discharge experiments on the EAST tokamak. In this note, a real-time remote/local IF stability control system is described. The measured plasma parameters, including the Faraday rotation angle, electron density, lower hybrid wave, and plasma current, are obtained with the aid of this newly developed IF stability control system.

  10. Numerical solutions of the complete Navier-Stokes equations

    NASA Technical Reports Server (NTRS)

    Hassan, H. A.

    1986-01-01

    Using ideas from the kinetic theory, the Navier-Stokes equations are modified in such a way that they can be cast as a set of first order hyperbolic equations. This is achieved by incorporating time dependent terms into the definition of the stress tensor and the heat flux vectors. The boundary conditions are then determined from the theory of characteristics. Because the resulting equations reduce to the traditional Navier-Stokes equations when the steady state is reached, the present approach provides a straightforward scheme for the determination of inflow and outflow boundary conditions. The method is validated by comparing its predictions with known exact solutions of the steady Navier-Stokes equations.

  11. Navier-Stokes calculations of scramjet-nozzle-afterbody flowfields

    NASA Technical Reports Server (NTRS)

    Baysal, Oktay

    1991-01-01

    A comprehensive computational fluid dynamics effort was conducted from 1987 to 1990 to properly design a nozzle and lower aft end of a generic hypersonic vehicle powered by a scramjet engine. The interference of the exhaust on the control surfaces of the vehicle can have adverse effects on its stability. Two-dimensional Navier-Stokes computations were performed, where the exhaust gas was assumed to be air behaving as a perfect gas. Then the exhaust was simulated by a mixture of Freon-12 and argon, which required solving the Navier-Stokes equations for four species: (nitrogen, oxygen, Freon-12, and argon). This allowed gamma to be a field variable during the mixing of the multispecies gases. Two different mixing models were used and comparisons between them as well as the perfect gas air calculations were made to assess their relative merits. Finally, the three dimensional Navier-Stokes computations were made for the full-span scramjet nozzle afterbody module.

  12. Clustering algorithms for Stokes space modulation format recognition.

    PubMed

    Boada, Ricard; Borkowski, Robert; Monroy, Idelfonso Tafur

    2015-06-15

    Stokes space modulation format recognition (Stokes MFR) is a blind method enabling digital coherent receivers to infer modulation format information directly from a received polarization-division-multiplexed signal. A crucial part of the Stokes MFR is a clustering algorithm, which largely influences the performance of the detection process, particularly at low signal-to-noise ratios. This paper reports on an extensive study of six different clustering algorithms: k-means, expectation maximization, density-based DBSCAN and OPTICS, spectral clustering and maximum likelihood clustering, used for discriminating between dual polarization: BPSK, QPSK, 8-PSK, 8-QAM, and 16-QAM. We determine essential performance metrics for each clustering algorithm and modulation format under test: minimum required signal-to-noise ratio, detection accuracy and algorithm complexity.

  13. Time dependent electromagnetic fields and 4-dimensional Stokes' theorem

    NASA Astrophysics Data System (ADS)

    Andosca, Ryan; Singleton, Douglas

    2016-11-01

    Stokes' theorem is central to many aspects of physics—electromagnetism, the Aharonov-Bohm effect, and Wilson loops to name a few. However, the pedagogical examples and research work almost exclusively focus on situations where the fields are time-independent so that one need only deal with purely spatial line integrals (e.g., ∮ A . d x ) and purely spatial area integrals (e.g., ∫ ( ∇ × A ) . d a = ∫ B . d a ). Here, we address this gap by giving some explicit examples of how Stokes' theorem plays out with time-dependent fields in a full 4-dimensional spacetime context. We also discuss some unusual features of Stokes' theorem with time-dependent fields related to gauge transformations and non-simply connected topology.

  14. Analysis of the data from Compton X-ray polarimeters which measure the azimuthal and polar scattering angles

    NASA Astrophysics Data System (ADS)

    Krawczynski, H.

    2011-05-01

    X-ray polarimetry has the potential to make key-contributions to our understanding of galactic compact objects like binary black hole systems and neutron stars, and extragalactic objects like active galactic nuclei, blazars, and Gamma-Ray Bursts. Furthermore, several particle astrophysics topics can be addressed including uniquely sensitive tests of Lorentz invariance. In the energy range from 10 keV to several MeV, Compton polarimeters achieve the best performance. In this paper we evaluate the benefit that comes from using the azimuthal and polar angles of the Compton scattered photons in the analysis, rather than using the azimuthal scattering angles alone. We study the case of an ideal Compton polarimeter and show that a Maximum Likelihood analysis which uses the two scattering angles lowers the Minimum Detectable Polarization (MDP) by ≈20% compared to a standard analysis based on the azimuthal scattering angles alone. The accuracies with which the polarization fraction and the polarization direction can be measured improve by a similar amount. We conclude by discussing potential applications of Maximum Likelihood analysis methods for various polarimeter experiments.

  15. Bandwidth optimization of femtosecond pure-rotational coherent anti-Stokes Raman scattering by pump/Stokes spectral focusing.

    DOE PAGES

    Kearney, Sean Patrick

    2014-07-01

    A simple spectral focusing scheme for bandwidth optimization of gas-phase rotational coherent anti-Stokes Raman scattering (CARS) spectra is presented. The method is useful when femtosecond pump/Stokes preparation of the Raman coherence is utilized. The approach is of practical utility when working with laser pulses that are not strictly transform limited, or when windows or other sources of pulse chirp may be present in the experiment. A delay between the femtosecond preparation pulses is introduced to shift the maximum Raman preparation away from zero frequency and toward the Stokes or anti-Stokes side of the spectrum with no loss in total preparationmore » bandwidth. Shifts of 100 cm-1 or more are attainable and allow for enhanced detection of high-energy (150-300 cm-1) rotational Raman transitions at near transform-limited optimum sensitivity. A simple theoretical treatment for the case of identical pump and Stokes pulses with linear frequency chirp is presented. The approach is then demonstrated experimentally for typical levels of transform-limited laser performance obtained our laboratory with nonresonant CARS in argon and Raman-resonant spectra from a lean H2/air flat flame.« less

  16. Bandwidth optimization of femtosecond pure-rotational coherent anti-Stokes Raman scattering by pump/Stokes spectral focusing.

    SciTech Connect

    Kearney, Sean Patrick

    2014-07-01

    A simple spectral focusing scheme for bandwidth optimization of gas-phase rotational coherent anti-Stokes Raman scattering (CARS) spectra is presented. The method is useful when femtosecond pump/Stokes preparation of the Raman coherence is utilized. The approach is of practical utility when working with laser pulses that are not strictly transform limited, or when windows or other sources of pulse chirp may be present in the experiment. A delay between the femtosecond preparation pulses is introduced to shift the maximum Raman preparation away from zero frequency and toward the Stokes or anti-Stokes side of the spectrum with no loss in total preparation bandwidth. Shifts of 100 cm-1 or more are attainable and allow for enhanced detection of high-energy (150-300 cm-1) rotational Raman transitions at near transform-limited optimum sensitivity. A simple theoretical treatment for the case of identical pump and Stokes pulses with linear frequency chirp is presented. The approach is then demonstrated experimentally for typical levels of transform-limited laser performance obtained our laboratory with nonresonant CARS in argon and Raman-resonant spectra from a lean H2/air flat flame.

  17. Bandwidth optimization of femtosecond pure-rotational coherent anti-Stokes Raman scattering by pump/Stokes spectral focusing.

    PubMed

    Kearney, Sean P

    2014-10-01

    A simple spectral focusing scheme for bandwidth optimization of gas-phase rotational coherent anti-Stokes Raman scattering (CARS) spectra is presented. The method is useful when femtosecond pump/Stokes preparation of the Raman coherence is utilized. The approach is of practical utility when working with laser pulses that are not strictly transform limited or when windows or other sources of pulse chirp may be present in the experiment. A delay between the femtosecond preparation pulses is introduced to shift the maximum Raman preparation away from zero frequency and toward the Stokes or anti-Stokes side of the spectrum with no loss in total preparation bandwidth. Shifts of 100 cm(-1) or more are attainable and allow for enhanced detection of high-energy (150-300 cm(-1)) rotational Raman transitions at near-transform-limited optimum sensitivity. A simple theoretical treatment for the case of identical pump and Stokes pulses with linear frequency chirp is presented. The approach is then demonstrated experimentally for typical levels of transform-limited laser performance obtained in our laboratory with nonresonant CARS in argon and Raman-resonant spectra from a lean H2 air flat flame.

  18. A dual potential formulation of the Navier-Stokes equations

    NASA Technical Reports Server (NTRS)

    Gegg, S. G.; Pletcher, R. H.; Steger, J. L.

    1989-01-01

    A dual potential formulation for numerically solving the Navier-Stokes equations is developed and presented. The velocity field is decomposed using a scalar and vector potential. Vorticity and dilatation are used as the dependent variables in the momentum equations. Test cases in two dimensions verify the capability to solve flows using approximations from potential flow to full Navier-Stokes simulations. A three-dimensional incompressible flow formulation is also described. An interesting feature of this approach to solving the Navier-Stokes equations is the decomposition of the velocity field into a rotational part (vector potential) and an irrotational part (scalar potential). The Helmholtz decomposition theorem allows this splitting of the velocity field. This approach has had only limited use since it increases the number of dependent variables in the solution. However, it has often been used for incompressible flows where the solution scheme is known to be fast and accurate. This research extends the usage of this method to fully compressible Navier-Stokes simulations by using the dilatation variable along with vorticity. A time-accurate, iterative algorithm is used for the uncoupled solution of the governing equations. Several levels of flow approximation are available within the framework of this method. Potential flow, Euler and full Navier-Stokes solutions are possible using the dual potential formulation. Solution efficiency can be enhanced in a straightforward way. For some flows, the vorticity and/or dilatation may be negligible in certain regions (e.g., far from a viscous boundary in an external flow). It is possible to drop the calculation of these variables then and optimize the solution speed. Also, efficient Poisson solvers are available for the potentials. The relative merits of non-primitive variables versus primitive variables for solution of the Navier-Stokes equations are also discussed.

  19. Beam Size Measurement by Optical Diffraction Radiation and Laser System for Compton Polarimeter

    SciTech Connect

    Liu, Chuyu

    2012-12-31

    Beam diagnostics is an essential constituent of any accelerator, so that it is named as "organs of sense" or "eyes of the accelerator." Beam diagnostics is a rich field. A great variety of physical effects or physical principles are made use of in this field. Some devices are based on electro-magnetic influence by moving charges, such as faraday cups, beam transformers, pick-ups; Some are related to Coulomb interaction of charged particles with matter, such as scintillators, viewing screens, ionization chambers; Nuclear or elementary particle physics interactions happen in some other devices, like beam loss monitors, polarimeters, luminosity monitors; Some measure photons emitted by moving charges, such as transition radiation, synchrotron radiation monitors and diffraction radiation-which is the topic of the first part of this thesis; Also, some make use of interaction of particles with photons, such as laser wire and Compton polarimeters-which is the second part of my thesis. Diagnostics let us perceive what properties a beam has and how it behaves in a machine, give us guideline for commissioning, controlling the machine and indispensable parameters vital to physics experiments. In the next two decades, the research highlight will be colliders (TESLA, CLIC, JLC) and fourth-generation light sources (TESLA FEL, LCLS, Spring 8 FEL) based on linear accelerator. These machines require a new generation of accelerator with smaller beam, better stability and greater efficiency. Compared with those existing linear accelerators, the performance of next generation linear accelerator will be doubled in all aspects, such as 10 times smaller horizontal beam size, more than 10 times smaller vertical beam size and a few or more times higher peak power. Furthermore, some special positions in the accelerator have even more stringent requirements, such as the interaction point of colliders and wigglor of free electron lasers. Higher performance of these accelerators increases the

  20. Stokes parameters and polarization contrasts in Young's interference experiment.

    PubMed

    Setälä, Tero; Tervo, Jani; Friberg, Ari T

    2006-07-15

    We derive a spectral interference law that governs the behavior of the four Stokes parameters in Young's two-pinhole experiment with a random electromagnetic beam. In addition to the visibility of intensity fringes, we introduce three new contrast parameters that describe the interference-induced changes in the field's state of partial polarization. The polarization modulation depends on the electric field correlations at the pinholes and is closely related to the two-point Stokes parameters. The results are expected to be particularly useful in polarization interferometry and electromagnetic coherence theory. The formalism is demonstrated with specific examples.

  1. Newman-Penrose Stokes fields for radio astronomy

    SciTech Connect

    Newman, Ezra T.; Price, Richard H.

    2010-10-15

    The spin weighted spherical harmonic (SWSH) description of angular functions is typically associated with the Newman-Penrose (NP) null tetrad formalism. Recently, the SWSH description, but not the NP formalism, has been used in the study of the polarization anisotropy of the cosmic microwave background. Here we relate this application of SWSHs to a description of electromagnetic radiation and polarization in the NP formalism. In particular, we introduce NP Stokes fields that are the NP equivalent of the Stokes parameters. In addition to giving a more coherent foundation for the recent cosmological SWSH application, the NP formalism aids in the computation of the Lorentz transformation properties of polarization.

  2. Third Stokes parameter emission from a periodic water surface

    NASA Technical Reports Server (NTRS)

    Johnson, J. T.; Kong, J. A.; Shin, R. T.; Staelin, D. H.; Oneill, K.; Lohanick, A.

    1991-01-01

    An experiment in which the third Stokes parameter thermal emission from a periodic water surface was measured is documented. This parameter is shown to be related to the direction of periodicity of the periodic surface and to approach brightnesses of up to 30 K at X band for the surface used in the experiment. The surface actually analyzed was a 'two-layer' periodic surface; the theory of thermal emission from such a surface is derived and the theoretical results are found to be in good agreement with the experimental measurements. These results further the idea of using the third Stokes parameter emission as an indicator of wind direction over the ocean.

  3. Size estimates of an obstacle in a stationary Stokes fluid

    NASA Astrophysics Data System (ADS)

    Beretta, E.; Cavaterra, C.; Ortega, J. H.; Zamorano, S.

    2017-02-01

    In this work we are interested in estimating the size of a cavity D immersed in a bounded domain Ω \\subset {{{R}}d}, d  =  2, 3, filled with a viscous fluid governed by the Stokes system, by means of velocity and Cauchy forces on the external boundary \\partial Ω . More precisely, we establish some lower and upper bounds in terms of the difference between the external measurements when the obstacle is present and without the object. The proof of the result is based on interior regularity results and quantitative estimates of unique continuation for the solution of the Stokes system.

  4. Inherent photoluminescence Stokes shift in GaAs.

    PubMed

    Ullrich, Bruno; Singh, Akhilesh K; Barik, Puspendu; Xi, Haowen; Bhowmick, Mithun

    2015-06-01

    The intrinsic photoluminescence Stokes shift, i.e., the energy difference between optical band gap and emission peak, of 350 μm thick semi-insulating GaAs wafers is found to be 4 meV at room temperature. The result is based on the determination of the optical bulk band gap from the transmission trend via modified Urbach rule whose result is confirmed with the transmission derivative method. The findings reveal the detailed balance of the optically evoked transitions and disclose the intrinsic link between Stokes shift and the Urbach tail slope parameter.

  5. On the solution of Stokes equations for plane boundaries

    NASA Astrophysics Data System (ADS)

    Qin, Y.; Sun, R.

    2017-02-01

    In a recent paper (Li et al., Acta Mech. Sin. 31, 32-44, 2015), the authors claimed that the general solution of steady Stokes flows can be compactly expressed using only two harmonic functions. They present two cases of a flat plate translating through a viscous fluid. The present paper shows that such a two-harmonic solution does not describe the rotation of a circular plate in an unbounded fluid and thus confirms that at least three independent harmonics are required to express the general solution of Stokes equations.

  6. Convergence acceleration of an aeroelastic Navier-Stokes solver

    NASA Technical Reports Server (NTRS)

    Obayashi, S.; Guruswamy, G.

    1994-01-01

    New capabilities have been added to a Navier-Stokes solver to perform steady-state simulations more efficiently. The flow solver for solving the Navier-Stokes equations is completely rewritten with a combination of the LU-SGS (Lower-Upper factored Symmetric Gauss-Seidel) implicit method and the modified HLLE (Harten-Lax-van Leer-Einfeldt) upwind scheme. A pseudo-time marching method is used for the directly coupled structural equations to improve overall convergence rates for static aeroelastic analysis. Results are demonstrated for transonic flows over rigid and flexible wings.

  7. Factorization of the Compressible Navier-Stokes Equations

    NASA Technical Reports Server (NTRS)

    Roberts, Thomas W.

    2005-01-01

    The Navier-Stokes equations for a Newtonian ideal gas are examined to determine the factorizable form of the equations relevant to the construction of a factorizable relaxation scheme. The principal linearization of the equations is found by examining the relative magnitude of the terms for short-wavelength errors. The principal part of the operator is then found. Comparison of the factors of the Navier-Stokes and Euler equations differ qualitatively because of the coupling of entropy and pressure through thermal diffusion. Special cases of the factorization are considered.

  8. Stellar magnetic fields from four Stokes parameter observations

    NASA Astrophysics Data System (ADS)

    Rusomarov, N.; Kochukhov, O.; Piskunov, N.

    2015-01-01

    Magnetic Doppler imaging (MDI) from observations of four Stokes parameters can uncover new information that is of interest to the evolution and structure of magnetic fields of intermediate and high-mass stars. Our MDI study of the chemically peculiar star HD 24712 from four Stokes parameter observations, obtained with the HARPSpol instrument at the 3.6-m ESO telescope, revealed a magnetic field with strong dipolar component and weak small-scale contributions. This finding gives evidence for the hypothesis that old Ap stars have predominantly dipolar magnetic fields.

  9. Algorithm implementation on the Navier-Stokes computer

    NASA Technical Reports Server (NTRS)

    Krist, Steven E.; Zang, Thomas A.

    1987-01-01

    The Navier-Stokes Computer is a multi-purpose parallel-processing supercomputer which is currently under development at Princeton University. It consists of multiple local memory parallel processors, called Nodes, which are interconnected in a hypercube network. Details of the procedures involved in implementing an algorithm on the Navier-Stokes computer are presented. The particular finite difference algorithm considered in this analysis was developed for simulation of laminar-turbulent transition in wall bounded shear flows. Projected timing results for implementing this algorithm indicate that operation rates in excess of 42 GFLOPS are feasible on a 128 Node machine.

  10. Navier-Stokes computations useful in aircraft design

    NASA Technical Reports Server (NTRS)

    Holst, Terry L.

    1990-01-01

    Large scale Navier-Stokes computations about aircraft components as well as reasonably complete aircraft configurations are presented and discussed. Speed and memory requirements are described for various general problem classes, which in some cases are already being used in the industrial design environment. Recent computed results, with experimental comparisons when available, are included to highlight the presentation. Finally, prospects for the future are described and recommendations for areas of concentrated research are indicated. The future of Navier-Stokes computations is seen to be rapidly expanding across a broad front of applications, which includes the entire subsonic-to-hypersonic speed regime.

  11. Pseudo-time algorithms for the Navier-Stokes equations

    NASA Technical Reports Server (NTRS)

    Swanson, R. C.; Turkel, E.

    1986-01-01

    A pseudo-time method is introduced to integrate the compressible Navier-Stokes equations to a steady state. This method is a generalization of a method used by Crocco and also by Allen and Cheng. We show that for a simple heat equation that this is just a renormalization of the time. For a convection-diffusion equation the renormalization is dependent only on the viscous terms. We implement the method for the Navier-Stokes equations using a Runge-Kutta type algorithm. This permits the time step to be chosen based on the inviscid model only. We also discuss the use of residual smoothing when viscous terms are present.

  12. Measurement of Aerosol and Cloud Particles with PACS and HARP Hyperangular Imaging Polarimeters

    NASA Astrophysics Data System (ADS)

    Martins, J.; Fernandez-Borda, R.; Remer, L. A.; Sparr, L.; Buczkowski, S.; Munchak, L. A.

    2013-12-01

    PACS is new hyper-angular imaging polarimeter for aeorosol and cloud measurerents designed to meet the requirements of the proposed ACE decadal survey mission. The full PACS system consists of three wide field of view (110deg cross track) telescopes covering the UV, VNIR, and SWIR spectral ranges with angular coverage between +55 deg forward to -55deg backwards. The angular density can be selected to cover up to 100 different viewing angles at selected wavelengths. PACS_VNIR is a prototype airborne instrument designed to demonstrate PACS capability by deploying just one of the three wavelength modules of the full PACS. With wavelengths at 470, 550, 675, 760 and 875nm, PACS_VNIR flew for the first time during the PODEX experiment in January/February 2013 aboard the NASA ER-2 aircraft. PACS SWIR (1.64, 1.88, 2.1, and 2.25um) is currently under construction and should be operational in the lab by Fall/2013. PACS_ UV has been fully designed, but is not yet under construction. During the PODEX flights PACS_VNIR collected data for aerosol and clouds over variable surface types including, water, vegetation, urban areas, and snow. The data is currently being calibrated, geolocated and prepared for the inversion of geophysical parameters including water cloud size distribution and aerosol microphysical parameters. The large density of angles in PACS allows for the characterization of cloudbow features in relatively high spatial resolution in a pixel to pixel basis. This avoids the need for assumptions of cloud homogeneity over any distance. The hyperangle capability also allows detailed observation of cloud ice particles, surface characterization, and optimum selection of the number of angles desired for aerosol retrievals. The aerosol and cloud retrieval algorithms under development for the retrieval of particle microphysical properties from the PACS data will be discussed in this presentation. As an extension of the PACS concept we are currently developing the HARP (Hyper

  13. Latest Progress on the Gamma-Ray Imager/Polarimeter for Solar Flares (GRIPS)

    NASA Astrophysics Data System (ADS)

    Shih, A. Y.; Lin, R. P.; Hurford, G. J.; Duncan, N. A.; Saint-Hilaire, P.; Smith, D. M.; Tajima, H.; Amman, M.; Grips Team

    2011-12-01

    We present the latest progress on building the balloon-borne Gamma-Ray Imager/Polarimeter for Solar flares (GRIPS) instrument, including testing and calibration of the detectors and development of the imaging and aspect systems. A continental-US test flight is slated for fall 2012. GRIPS will provide a near-optimal combination of high-resolution imaging, spectroscopy, and polarimetry of solar-flare gamma-ray/hard X-ray emissions from ~20 keV to >~10 MeV. The spectrometer/polarimeter consists of sixteen 3D position-sensitive germanium detectors (3D-GeDs), where each energy deposition is individually recorded with an energy resolution of a few keV FWHM and a spatial resolution to within <0.1 mm^3. Imaging is accomplished by a single multi-pitch rotating modulator (MPRM), a 2.5-cm thick tungsten-alloy grid with pitches that range quasi-continuously from 1 to 13 mm. With the MPRM situated 8 meters from the spectrometer, this instrument will provide excellent image quality and unparalleled angular resolution at gamma-ray energies (12.5 arcsec FWHM), sufficient to separate the 2.2 MeV footpoint sources for almost all flares. Polarimetry is accomplished by analyzing the anisotropy of reconstructed Compton scattering in the 3D-GeDs (i.e. as an active scatterer), with an estimated minimum detectable polarization of a few percent at 150-650 keV in an X-class flare. GRIPS will address questions relevant to particle acceleration and energy release that have been raised by recent solar flare observations, such as: What causes the spatial separation between energetic electron producing hard X-rays and energetic ions producing gamma-ray lines? How anisotropic are the accelerated electrons, and why do relativistic electron dominate in the corona? How does the composition of accelerated and ambient material vary with space and time, and why?

  14. Retrievals of cloud microphysical properties from the Research Scanning Polarimeter measurements made during PODEX field campaign

    NASA Astrophysics Data System (ADS)

    Alexandrov, M. D.; Cairns, B.; Sinclair, K.

    2013-12-01

    We present the retrievals of cloud droplet size distribution parameters (effective radius and variance) from the Research Scanning Polarimeter (RSP) measurements made during NASA's POlarimeter Definition EXperiment (PODEX), which was based in Palmdale, California in January - February 2013. The RSP is an airborne prototype for the Aerosol Polarimetery Sensor (APS), which was built for the NASA Glory Mission project. This instrument measures both polarized and total reflectances in 9 spectral channels with center wavelengths of 410, 470, 555, 670, 865, 960, 1590, 1880 and 2250 nm. The RSP is a push broom scanner making samples at 0.8 degree intervals within 60 degrees from nadir in both forward and backward directions. The data from actual RSP scans is aggregated into "virtual" scans, each consisting of all reflectances (at a variety of scattering angles) from a single point on the ground or at the cloud top. In the case of water clouds the rainbow is observed in the polarized reflectances in the scattering angle range between 135 and 170 degrees. It has a unique signature that is being used to accurately determine the droplet size and is not affected by cloud morphology. Simple parametric fitting algorithm applied to these polarized reflectances provides retrievals of the droplet effective radius and variance assuming a prescribed size distribution shape (gamma distribution). In addition to this, we use a non-parametric method, Rainbow Fourier Transform (RFT), which allows to retrieve the droplet size distribution a parametric model. Of particular interest is the information contained in droplet size distribution width, which is indicative of cloud life cycle. The absorbing band method is also applied to RSP total reflectance observations. The difference in the retrieved droplet size between polarized and absorbing band techniques is expected to reflect the strength of the vertical gradient in cloud liquid water content. In addition to established retrieval

  15. Latest Progress on the Gamma-Ray Imager/Polarimeter for Solar Flares (GRIPS)

    NASA Technical Reports Server (NTRS)

    Shih, Albert Y.; Lin, Robert P.; Hurford, Gordon J.; Duncan, Nicole A.; Saint-Hilaire, Pascal; Smith, David Miles; Tajima, Hiroyasu; Amman, Mark

    2011-01-01

    We present the latest progress on building the balloon-borne Gamma-Ray Imager/Polarimeter for Solar flares (GRIPS) instrument, including testing and calibration of the detectors and development of the imaging and aspect systems. A continental-US test flight is slated for fall 2012. GRIPS will provide a near-optimal combination of high-resolution imaging, spectroscopy, and polarimetry of solar-flare gamma-ray/hard X-ray emissions from approx.20. keV to > approx.10 MeV. The spectrometer/polarimeter consists of sixteen 3D position-sensitive germanium detectors (3D-GeDs), where each energy deposition is individually recorded with an energy resolution of a few keV FWHM and a spatial resolution to within <0.1 cu mm. Imaging is accomplished by a single multi-pitch rotating modulator (MPRM), a 2.5-cm thick tungsten-alloy grid with pitches that range quasi-continuously from 1 to 13 mm. With the MPRM situated 8 meters from the spectrometer, this instrument will provide excellent image quality and unparalleled angular resolution at gamma-ray energies (12.5 arcsec FWHM), sufficient to separate the 2.2 MeV footpoint sources for almost all flares. Polarimetry is accomplished by analyzing the anisotropy of reconstructed Compton scattering in the 3D-GeDs (i.e. as an active scatterer), with an estimated minimum detectable polarization of a few percent at 150-650 keV in an X-class flare. GRIPS will address questions relevant to particle acceleration and energy release that ha-.e been raised by recent solar flare observations, such as: What causes the spatial separation between energetic electron producing hard X-rays and energetic ions producing gamma-ray lines? How anisotropic are the accelerated electrons, and why do relativistic electron dominate in the corona? How does the composition of accelerated and ambient material vary with space and time, and why?

  16. Combined Retrievals of Boreal Forest Fire Aerosol Properties with a Polarimeter and Lidar

    NASA Technical Reports Server (NTRS)

    Knobelspiesse, K.; Cairns, B.; Ottaviani, M.; Ferrare, R.; Haire, J.; Hostetler, C.; Obland, M.; Rogers, R.; Redemann, J.; Shinozuka, Y.; Clarke, A.; Freitag, S.; Howell, S.; Kapustin, V.; McNaughton, C.

    2011-01-01

    Absorbing aerosols play an important, but uncertain, role in the global climate. Much of this uncertainty is due to a lack of adequate aerosol measurements. While great strides have been made in observational capability in the previous years and decades, it has become increasingly apparent that this development must continue. Scanning polarimeters have been designed to help resolve this issue by making accurate, multi-spectral, multi-angle polarized observations. This work involves the use of the Research Scanning Polarimeter (RSP). The RSP was designed as the airborne prototype for the Aerosol Polarimetery Sensor (APS), which was due to be launched as part of the (ultimately failed) NASA Glory mission. Field observations with the RSP, however, have established that simultaneous retrievals of aerosol absorption and vertical distribution over bright land surfaces are quite uncertain. We test a merger of RSP and High Spectral Resolution Lidar (HSRL) data with observations of boreal forest fire smoke, collected during the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS). During ARCTAS, the RSP and HSRL instruments were mounted on the same aircraft, and validation data were provided by instruments on an aircraft flying a coordinated flight pattern. We found that the lidar data did indeed improve aerosol retrievals using an optimal estimation method, although not primarily because of the constraints imposed on the aerosol vertical distribution. The more useful piece of information from the HSRL was the total column aerosol optical depth, which was used to select the initial value (optimization starting point) of the aerosol number concentration. When ground based sun photometer network climatologies of number concentration were used as an initial value, we found that roughly half of the retrievals had unrealistic sizes and imaginary indices, even though the retrieved spectral optical depths agreed within uncertainties to

  17. The Gamma-Ray Imager/Polarimeter For Solar Flares (GRIPS)

    NASA Astrophysics Data System (ADS)

    Shih, Albert Y.; Lin, R. P.; Hurford, G. J.; Boggs, S. E.; Zoglauer, A. C.; Wunderer, C. B.; Sample, J. G.; Turin, P.; McBride, S.; Smith, D. M.; Tajima, H.; Luke, P. N.; Amman, M. S.

    2009-01-01

    The new balloon-borne Gamma-Ray Imager/Polarimeter for Solar flares (GRIPS) instrument will provide a near-optimal combination of high-resolution imaging, spectroscopy, and polarimetry of solar-flare gamma-ray/hard X-ray emissions from 20 keV to > 10 MeV. GRIPS will address questions relevant to particle acceleration and energy release that have been raised by recent solar flare observations, such as: What causes the spatial separation between energetic electron producing hard X-rays and energetic ions producing gamma-ray lines? How anisotropic are the accelerated electrons, and why do relativistic electron dominate in the corona? How does the composition of accelerated and ambient material vary with space and time, and why? The spectrometer/polarimeter consists of sixteen 3D position-sensitive germanium detectors (3D-GeDs), where each energy deposition is individually recorded. Imaging is accomplished by a single multi-pitch rotating modulator (MPRM) situated 8 meters from the spectrometer to provide excellent image quality and unparalleled angular resolution at gamma-ray energies (12.5 arcsec FWHM), using a similar technique to rotating-modulation-collimator imaging used on missions such as RHESSI but now taking advantage of the position sensitivity of the spectrometer. Polarimetry is accomplished by analyzing the anisotropy of reconstructed Compton scattering in the 3D-GeDs (i.e. as an active scatterer). A balloon platform for this instrument minimizes atmospheric attenuation and accommodates its weight and size, and long-duration balloon flights (LDBFs) from Antarctica allow for month-long uninterrupted observations of the Sun to continuously observe active regions and to maximize the chance of capturing a gamma-ray flare. A continental-US test flight is slated for 2012 with the eventual goal of Antarctic LDBFs of the completed instrument. In addition to the direct science return from these flights, GRIPS will prove these technologies for a future space

  18. The Gamma-Ray Imager/Polarimeter For Solar Flares (GRIPS)

    NASA Astrophysics Data System (ADS)

    Shih, Albert Y.; Lin, R. P.; Hurford, G. J.; Boggs, S. E.; Zoglauer, A. C.; Wunderer, C. B.; Sample, J. G.; Turin, P.; McBride, S.; Smith, D. M.; Tajima, H.; Luke, P. N.; Amman, M. S.

    2009-05-01

    The new balloon-borne Gamma-Ray Imager/Polarimeter for Solar flares (GRIPS) instrument will provide a near-optimal combination of high-resolution imaging, spectroscopy, and polarimetry of solar-flare gamma-ray/hard X-ray emissions from 20 keV to > 10 MeV. GRIPS will address questions relevant to particle acceleration and energy release that have been raised by recent solar flare observations, such as: What causes the spatial separation between energetic electron producing hard X-rays and energetic ions producing gamma-ray lines? How anisotropic are the accelerated electrons, and why do relativistic electron dominate in the corona? How does the composition of accelerated and ambient material vary with space and time, and why? The spectrometer/polarimeter consists of sixteen 3D position-sensitive germanium detectors (3D-GeDs), where each energy deposition is individually recorded. Imaging is accomplished by a single multi-pitch rotating modulator (MPRM) situated 8 meters from the spectrometer to provide excellent image quality and unparalleled angular resolution at gamma-ray energies (12.5 arcsec FWHM), using a similar technique to rotating-modulation-collimator imaging used on missions such as RHESSI but now taking advantage of the position sensitivity of the spectrometer. Polarimetry is accomplished by analyzing the anisotropy of reconstructed Compton scattering in the 3D-GeDs (i.e. as an active scatterer). A balloon platform for this instrument minimizes atmospheric attenuation and accommodates its weight and size, and long-duration balloon flights (LDBFs) from Antarctica allow for month-long uninterrupted observations of the Sun to continuously observe active regions and to maximize the chance of capturing a gamma-ray flare. A continental-US test flight is slated for 2012 with the eventual goal of Antarctic LDBFs of the completed instrument. In addition to the direct science return from these flights, GRIPS will prove these technologies for a future space

  19. The three-wave laser polarimeter-interferometer on J-TEXT tokamak

    NASA Astrophysics Data System (ADS)

    Zhuang, G.; Liu, Y.; Chen, J.; Gao, L.; Li, Q.; Xiong, C. Y.; Shi, P.; Zhou, Y. N.

    2016-02-01

    Motivated by increasing demands on high-quality measurement of interior magnetic field in tokamak plasma, a far-infrared laser-based polarimeter-interferometer system has been developed on J-TEXT. Three formic acid lasers separately pumped by three CO2 lasers are used as sources, providing more than 90 mW output power in total. High laser power along with usage of newly developed planar Schottky diode mixer enable high phase resolution < 1 mrad. Collinearity and polarization calibrations have been carefully done to improve the measurement reliability. Meanwhile, real-time feedback control of three-wave laser source has been realized for the first time, to fulfill the system stability. Based on three-wave technique, Faraday angle and integrated density phase along the laser path are simultaneously measured with high temporal resolution. In addition, the laser beam is expanded to cover the entire cross-section of the plasma to provide high spatial resolution measurement. With this system, MHD equilibrium of the J-TEXT plasma has been reconstructed. Obscure perturbations on magnetic topology and electron density associated with MHD instabilities, e.g. sawteeth and tearing modes have also been observed. In particular, some interesting features of disruptions in high-density discharges are identified by carefully interpreting the measured polarimeter-interferometer data. In the density ramp-up phase of a high density discharge, asymmetry in both electron density and current density profiles between the Low-Field-Side (LFS) edge (r > 0.8a) and the High-Field-Side (HFS) edge (r < -0.8a) would appear and extend gradually toward the center region. At the same time, a low-frequency (< 1 kHz) density perturbation suddenly occurs at the HFS edge and also gradually propagates into the center region. The disruption takes place when the electron density asymmetry/perturbation reaches the location nearly the m/n = 2/1 (where m and n are the toroidal mode number and the poloidal

  20. First flight of the Gamma-Ray Imager/Polarimeter for Solar flares (GRIPS)

    NASA Astrophysics Data System (ADS)

    Saint-Hilaire, Pascal; Shih, Albert Y.; Duncan, Nicole; Bain, Hazel; Maruca, Bennett A.; Kelley, Nicole; Godbole, Niharika; Kaufmann, Pierre; Caspi, Amir; Sample, John; Hoberman, Jane; Mochizuki, Brent; Olson, Jerry; Boggs, Steven E.; Zoglauer, Andreas; Hurford, Gordon J.; Smith, David M.; Tajima, Hiroyasu; Amman, Mark

    2016-05-01

    The Gamma-Ray Imager/Polarimeter for Solar flares (GRIPS) high altitude balloon payload was successfully flown in January 2016 from Antarctica (Jan 19 to Jan 30).GRIPS provides a near-optimal combination of high-resolution imaging, spectroscopy, and polarimetry of solar-flare gamma ray/hard X-ray emissions from ~20 keV to >~10 MeV. GRIPS’s goal is to address questions raised by recent solar flare observations regarding particle acceleration and energy release, such as: What causes the spatial separation between energetic electrons producing hard X-rays and energetic ions producing gamma-ray lines? How anisotropic are the relativistic electrons, and why can they dominate in the corona? How do the compositions of accelerated and ambient material vary with space and time, and why? The spectrometer/polarimeter consists of six 3D position-sensitive germanium detectors (3D-GeDs), where each energy deposition is individually recorded with an energy resolution of a few keV FWHM and a spatial resolution <0.1 mm3. Imaging is accomplished by a single multi-pitch rotating modulator (MPRM), a 2.5-cm thick tungsten alloy slit/slat grid with pitches that range quasi-continuously from 1 to 13 mm. The MPRM is situated 8 meters from the spectrometer to provide excellent image quality and unparalleled angular resolution at gamma-ray energies (12.5 arcsec FWHM), sufficient to separate 2.2 MeV footpoint sources for almost all flares. Polarimetry is accomplished by analyzing the anisotropy of reconstructed Compton scattering in the 3D-GeDs, with an estimated minimum detectable polarization of a few percent at 150-650 keV in an X-class flare. GRIPS was also equipped with active BGO shields, and three piggy-back instruments: a solar terahertz radiometer (Solar-T), a hard X-ray spectrometer (SMASH), and a sonic anemometer (TILDAE).We will present an overview of GRIPS's first flight, the performance of its instruments and subsystems, including the solar pointing and aspect systems, and

  1. Exponential integrators for the incompressible Navier-Stokes equations.

    SciTech Connect

    Newman, Christopher K.

    2004-07-01

    We provide an algorithm and analysis of a high order projection scheme for time integration of the incompressible Navier-Stokes equations (NSE). The method is based on a projection onto the subspace of divergence-free (incompressible) functions interleaved with a Krylov-based exponential time integration (KBEI). These time integration methods provide a high order accurate, stable approach with many of the advantages of explicit methods, and can reduce the computational resources over conventional methods. The method is scalable in the sense that the computational costs grow linearly with problem size. Exponential integrators, used typically to solve systems of ODEs, utilize matrix vector products of the exponential of the Jacobian on a vector. For large systems, this product can be approximated efficiently by Krylov subspace methods. However, in contrast to explicit methods, KBEIs are not restricted by the time step. While implicit methods require a solution of a linear system with the Jacobian, KBEIs only require matrix vector products of the Jacobian. Furthermore, these methods are based on linearization, so there is no non-linear system solve at each time step. Differential-algebraic equations (DAEs) are ordinary differential equations (ODEs) subject to algebraic constraints. The discretized NSE constitute a system of DAEs, where the incompressibility condition is the algebraic constraint. Exponential integrators can be extended to DAEs with linear constraints imposed via a projection onto the constraint manifold. This results in a projected ODE that is integrated by a KBEI. In this approach, the Krylov subspace satisfies the constraint, hence the solution at the advanced time step automatically satisfies the constraint as well. For the NSE, the projection onto the constraint is typically achieved by a projection induced by the L{sup 2} inner product. We examine this L{sup 2} projection and an H{sup 1} projection induced by the H{sup 1} semi-inner product. The H

  2. Simultaneous observation of rotational coherent Stokes Raman scattering and coherent anti-Stokes Raman scattering in air and nitrogen

    NASA Technical Reports Server (NTRS)

    Snow, J. B.; Chang, R. K.; Zheng, J. B.; Leipertz, A.

    1983-01-01

    Rotational coherent Stokes Raman scattering (CSRS) and coherent anti-Stokes Raman scattering (CARS) in air and in nitrogen were observed simultaneously by using broadband generation and detection. In the broadband technique used, the entire CARS and CSRS spectrum was generated in a single laser pulse; the CSRS and CARS signals were dispersed by a spectrograph and detected simultaneously by an optical multichannel analyzer. A three-dimensional phase-matching geometry was used to achieve spatial resolution of the CSRS and CARS beams from the input beams. Under resonant conditions, similar experiments may provide a means of investigating the possible interaction between the CSRS and CARS processes in driving the rotational levels.

  3. Tetrahedral Finite-Volume Solutions to the Navier-Stokes Equations on Complex Configurations

    NASA Technical Reports Server (NTRS)

    Frink, Neal T.; Pirzadeh, Shahyar Z.

    1998-01-01

    A review of the algorithmic features and capabilities of the unstructured-grid flow solver USM3Dns is presented. This code, along with the tetrahedral grid generator, VGRIDns, is being extensively used throughout the U.S. for solving the Euler and Navier-Stokes equations on complex aerodynamic problems. Spatial discretization is accomplished by a tetrahedral cell-centered finite-volume formulation using Roe's upwind flux difference splitting. The fluxes are limited by either a Superbee or MinMod limiter. Solution reconstruction within the tetrahedral cells is accomplished with a simple, but novel, multidimensional analytical formula. Time is advanced by an implicit backward-Euler time-stepping scheme. Flow turbulence effects are modeled by the Spalart-Allmaras one-equation model, which is coupled with a wall function to reduce the number of cells in the near-wall region of the boundary layer. The issues of accuracy and robustness of USM3Dns Navier-Stokes capabilities are addressed for a flat-plate boundary layer, and a full F-16 aircraft with external stores at transonic speed.

  4. Local feedback regularization of three-dimensional Navier-Stokes equations on bounded domains

    NASA Astrophysics Data System (ADS)

    Balogh, Andras

    One of the outstanding open problems in applied mathematics is the question of well-posedness of the initial boundary value problem associated with the three-dimensional fluid flow. At the same time, due to important applications in control theory, numerical analysis and turbulence, various types of regularizations and controls are gaining new interest. The specific problem we consider here is inspired by recent advances in the control of nonlinear distributed parameter systems and its possible applications to hydrodynamics. The main objective is to investigate the extent to which the 3-dimensional Navier-Stokes system can be regularized using a particular, physically motivated, feedback control law. The feedback is introduced in the form of an additional nonlinear viscosity term. Since control over the whole domain is not feasible in general, i.e., it is not usually possible to measure the entire state of the system, we consider a feedback supported only on a subdomain. On the rest of the domain the classical Navier-Stokes equations govern the fluid flow. The additional viscosity term is physically meaningful in the sense that it is proportional to the energy dissipation functional on the subdomain. For the controlled system we prove the existence, uniqueness and stability of the strong solution for initial data and forcing term which are arbitrary on the subdomain of control and are sufficiently small (in appropriate function spaces) outside this subdomain.

  5. Freedom Schooling: Stokely Carmichael and Critical Rhetorical Education

    ERIC Educational Resources Information Center

    Schneider, Stephen

    2006-01-01

    "Freedom Schooling" looks at a Freedom School class taught by Black Power activist Stokely Carmichael (Kwame Ture). Specifically, this article explores the philosophies of language and education that informed this class and the organic relationship fostered between the classroom and the political goals of African American communities during the…

  6. Analysis of regularized Navier-Stokes equations, 2

    NASA Technical Reports Server (NTRS)

    Ou, Yuh-Roung; Sritharan, S. S.

    1989-01-01

    A practically important regularization of the Navier-Stokes equations was analyzed. As a continuation of the previous work, the structure of the attractors characterizing the solutins was studied. Local as well as global invariant manifolds were found. Regularity properties of these manifolds are analyzed.

  7. Molecular Volumes and the Stokes-Einstein Equation

    ERIC Educational Resources Information Center

    Edward, John T.

    1970-01-01

    Examines the limitations of the Stokes-Einstein equation as it applies to small solute molecules. Discusses molecular volume determinations by atomic increments, molecular models, molar volumes of solids and liquids, and molal volumes. Presents an empirical correction factor for the equation which applies to molecular radii as small as 2 angstrom…

  8. A multidomain spectral collocation method for the Stokes problem

    NASA Technical Reports Server (NTRS)

    Landriani, G. Sacchi; Vandeven, H.

    1989-01-01

    A multidomain spectral collocation scheme is proposed for the approximation of the two-dimensional Stokes problem. It is shown that the discrete velocity vector field is exactly divergence-free and we prove error estimates both for the velocity and the pressure.

  9. Cavitation Modeling in Euler and Navier-Stokes Codes

    NASA Technical Reports Server (NTRS)

    Deshpande, Manish; Feng, Jinzhang; Merkle, Charles L.

    1993-01-01

    Many previous researchers have modeled sheet cavitation by means of a constant pressure solution in the cavity region coupled with a velocity potential formulation for the outer flow. The present paper discusses the issues involved in extending these cavitation models to Euler or Navier-Stokes codes. The approach taken is to start from a velocity potential model to ensure our results are compatible with those of previous researchers and available experimental data, and then to implement this model in both Euler and Navier-Stokes codes. The model is then augmented in the Navier-Stokes code by the inclusion of the energy equation which allows the effect of subcooling in the vicinity of the cavity interface to be modeled to take into account the experimentally observed reduction in cavity pressures that occurs in cryogenic fluids such as liquid hydrogen. Although our goal is to assess the practicality of implementing these cavitation models in existing three-dimensional, turbomachinery codes, the emphasis in the present paper will center on two-dimensional computations, most specifically isolated airfoils and cascades. Comparisons between velocity potential, Euler and Navier-Stokes implementations indicate they all produce consistent predictions. Comparisons with experimental results also indicate that the predictions are qualitatively correct and give a reasonable first estimate of sheet cavitation effects in both cryogenic and non-cryogenic fluids. The impact on CPU time and the code modifications required suggests that these models are appropriate for incorporation in current generation turbomachinery codes.

  10. 7. Interior detail, north to south, stoking floor, brick incinerator ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. Interior detail, north to south, stoking floor, brick incinerator housing reinforced with steel frame. - Charlestown Navy Yard, Incinerator, Midway along northern boundary of Charlestown Navy Yard, on Little Mystic Channel, near junction of Eighteenth Street & Second Avenue, Boston, Suffolk County, MA

  11. Stokes vector imaging of the polarized sky-dome

    NASA Astrophysics Data System (ADS)

    North, J. A.; Duggin, M. J.

    1997-01-01

    A practical method has been developed for obtaining partial Stokes vector (IQU_) and derivative (IPT_) images of the polarized sky-dome. This method takes advantage of a four-lens stereoscopic camera, a dome mirror, photo CD processing, and commercially available digital image-processing software.

  12. First results of Faraday-effect polarimeter measurements of internal magnetic fluctuation in DIII-D

    NASA Astrophysics Data System (ADS)

    Chen, J.; Ding, W. X.; Brower, D. L.

    2016-10-01

    Motivated by the need to measure fast equilibrium temporal dynamics, non-axisymmetric structures and core magnetic fluctuations (coherent and broadband), a 694 GHz Faraday-effect polarimeter has recently been installed on the DIII-D tokamak. A novel detection scheme is utilized, which results in simultaneous integral density measurement, to isolate the magnetic component, along with fast time response (up to 3MHz) and high phase resolution (1 ×10-4 degree2/kHz, equivalent to <1 Gauss at medium to high electron density conditions). Spatial resolution is provided by three radial chords located at z = 0 cm and z = +/- 13.5 cm (z = 0 cm is machine center). Simultaneous Faraday rotation and integral density measurements have been demonstrated in the experimental campaign of 2016, with good agreement with MSE-constrained EFIT. The change of Faraday rotation during sawteeth indicates periodic evolution of current density in the core plasma. Coherent and broadband fluctuations associated with plasma instabilities and turbulence, up to 500 kHz, have been observed on both Faraday rotation and integral density data. Supported by USDOE Grant DE-FC02-04ER54698 and DE-FG03-01ER54615.

  13. White light sunspot observations from the Solar Optical Universal Polarimeter on Spacelab-2

    NASA Technical Reports Server (NTRS)

    Shine, R. A.; Title, A. M.; Tarbell, T. D.; Topka, K. P.

    1987-01-01

    The flight of the Solar Optical Universal Polarimeter on Spacelab-2 provided the opportunity for the collection of time sequences of diffraction-limited (0.5 arcsec) solar images with excellent pointing stability (0.003 arcsec) and with freedom from the distortion that plagues ground-based images. A series of white-light images of active region 4682 were obtained on August 5, 1985, and the area containing the sunspot has been analyzed. These data have been digitally processed to remove noise and to separate waves from low-velocity material motions. The results include: (1) proper motion measurements of a radial outflow in the photospheric granulation pattern just outside the penumbra; (2) discovery of occasional bright structures ('streakers') that appear to be ejected outward from the penumbra; (3) broad dark 'clouds' moving outward in the penumbra, in addition to the well-known bright penumbral grains moving inward; (4) apparent extensions and contractions of penumbral filaments over the photosphere; and (5) observation of a faint bubble or looplike structure that seems to expand from two bright penumbral filaments into the photosphere.

  14. HX-POL - A Balloon-Bourne Hard X-Ray Polarimeter

    SciTech Connect

    Krawczynski, H.; De Geronimo, G.; Garson, A., III, Martin, J.; Li, Q.; Beilicke, M,; Dowkontt, P.; Lee, K.; Wulf, E.; Kurfess, J.; Novikova, E.; Baring, M.G.; Harding, A.K.; Grindlay, J.; Hong, J.S.

    2009-12-09

    We report on the design and estimated performance of a balloon-borne hard X-ray polarimeter called HX-POL. The experiment uses a combination of Si and Cadmium Zinc Telluride detectors to measure the polarization of 50 keV-400 keV X-rays from cosmic sources through the dependence of the angular distribution of Compton scattered photons on the polarization direction. On a one-day balloon flight, HX-POL would allow us to measure the polarization of bright Crab-like sources for polarization degrees well below 10%. On a longer (15-30 day) flight from Australia or Antarctica, HX-POL would be be able to measure the polarization of bright galactic X-ray sources down to polarization degrees of a few percent. Hard X-ray polarization measurements provide unique venues for the study of particle acceleration processes by compact objects and relativistic outflows. In this paper, we discuss the overall instrument design and performance. Furthermore, we present results from laboratory tests of the Si and CZT detectors.

  15. Faraday-Effect Polarimeter-Interferometer System for current density measurement on EAST

    NASA Astrophysics Data System (ADS)

    Liu, Haiqing; Jie, Yinxian; Ding, Weixing; Brower, David Lyn; Zou, Zhiyong; Li, Weiming; Qian, Jinping; Yang, Yao; Zeng, Long; Lan, Ting; Li, Gongshun; Hu, Liqun; Wan, Baonian

    2014-10-01

    A multichannel far-infrared laser-based POlarimeter-INTerferometer (POINT) system utilizing the three-wave technique is under development for current density and electron density profile measurements in the EAST tokamak. Novel molybdenum retro-reflectors are mounted in the inside wall for the double-pass optical arrangement. A Digital Phase Detector with 250 kHz bandwidth, which will provide real-time Faraday rotation angle and density phase shift output, have been developed for use on the POINT system. System time response (~1 microsecond) and phase resolution (<0.1°) allows resolution of fast equilibrium changes associated with MHD events. Initial calibration indicates the electron line-integrated density resolution is less than 5 × 1016 m-2 (~2°), and the Faraday rotation angle rms phase noise is <0.1°. Initial results of POINT system will be presented. This work is supported by the National Magnetic Confinement Fusion Program of China Contract No. 2012GB101002. This work is partly supported by the US D.O.E. Contract DESC0010469.

  16. A Concept for a High-Energy Gamma-ray Polarimeter

    NASA Technical Reports Server (NTRS)

    Bloser, P. F.; Hunter, S. D.; Depaola, G. O.; Longo, F.

    2003-01-01

    We present a concept for an imaging gamma-ray polarimeter operating from approx. 50 MeV to approx. 1 GeV. Such an instrument would be valuable for the study of high-energy pulsars, active galactic nuclei, supernova remnants, and gamma-ray bursts. The concept makes use of pixelized gas micro-well detectors, under development at Goddard Space Flight Center, to record the electron-positron tracks from pair-production events in a large gas volume. Pixelized micro-well detectors have the potential to form large-volume 3-D track imagers with approx. 100 micron (rms) position resolution at moderate cost. The combination of high spatial resolution and a continuous low-density gas medium permits many thousands of measurements per radiation length, allowing the particle tracks to be imaged accurately before multiple scattering masks their original directions. The polarization of the incoming radiation may then be determined from the azimuthal distribution of the electron-positron pairs. We have performed Geant4 simulations of these processes to estimate the polarization sensitivity as a function of instrument parameters and event selection criteria.

  17. The conceptual design of interferometer/polarimeter system on HL-2M

    NASA Astrophysics Data System (ADS)

    Zhou, Y.; Wang, H. X.; Li, Y. G.; Li, Y.; Chen, W. J.; Yi, J.; Deng, Z. C.

    2016-11-01

    HL-2M is a new medium-sized tokamak with major radius of 1.78 m, minor radius of 0.65 m, and aspect ratio of 2.8 and will be finished soon. In the conceptual design, a double-pass, horizontal view, multi-channel far-infrared (FIR) laser interferometer/polarimeter system (at 432 μm) is proposed to simultaneously measure the phase change and the Faraday rotation for density and current profile reconstruction. A vertical CO2 dispersion interferometer system (with wavelength of 10.6 μm and 5.3 μm) is designed to measure the line density, which will mainly be used for density feedback. The performance of the system is expected to meet the requirement of the measurements on HL-2M, with phase accuracy ˜0.1°, time resolution ˜1 μs, spatial resolution ˜7.2 cm, and density measurement range of 1 × 10 18-1 ×1021 m-3.

  18. Optimization of J-TEXT three-wave polarimeter-interferometer system

    NASA Astrophysics Data System (ADS)

    Li, Q.; Gao, L.; Chen, J.; Zhuang, G.; Wang, Z. J.; Liu, Y.; Chen, W.

    2013-10-01

    A laser-based three-wave polarimeter-interferometer system (POLARIS) is operational on J-TEXT tokamak (R=1.05 m, a=0.27 m) to measure plasma electron density and Faraday rotation angle simultaneously. Vibration and collinearity are two key factors which affect the accuracy of the measurement. Vibration at the amplitude of even 1 μm is able to induce almost 1° error (λ=432 μm) to the measurement through phase detection. And misalignment of collinearity can also cause systematic error to the measurement of Faraday angle due to density gradient and path length difference. Thus the systematic error from these two sources should be eliminated to obtain accurate equilibrium and fluctuation information of the plasma. Some work has been done on optimizing vibration and collinearity to achieve this goal. After optimization, POLARIS now has achieved 12 chord measurements (spacing of 3 cm) with high temporal and phase resolution. Details of the optimization and results are described in this study.

  19. Fast Data Processing of a Polarimeter-Interferometer System on J-TEXT

    NASA Astrophysics Data System (ADS)

    Liu, Yukai; Gao, Li; Liu, Haiqing; Yang, Yao; Gao, Xiang; J-Text Team

    2016-12-01

    A method of fast data processing has been developed to rapidly obtain evolution of the electron density profile for a multichannel polarimeter-interferometer system (POLARIS) on J-TEXT. Compared with the Abel inversion method, evolution of the density profile analyzed by this method can quickly offer important information. This method has the advantage of fast calculation speed with the order of ten milliseconds per normal shot and it is capable of processing up to 1 MHz sampled data, which is helpful for studying density sawtooth instability and the disruption between shots. In the duration of a flat-top plasma current of usual ohmic discharges on J-TEXT, shape factor u is ranged from 4 to 5. When the disruption of discharge happens, the density profile becomes peaked and the shape factor u typically decreases to 1. supported by the National Magnetic Confinement Fusion Science Program of China (Nos. 2014GB106000, 2014GB106002, and 2014GB106003) and National Natural Science Foundation of China (Nos. 11275234, 11375237 and 11505238) and Scientific Research Grant of Hefei Science Center of CAS (No. 2015SRG-HSC010)

  20. The First Multichroic Polarimeter Array on the Atacama Cosmology Telescope: Characterization and Performance

    NASA Technical Reports Server (NTRS)

    Ho, S. P.; Pappas, C. G.; Austermann, J.; Beall, J. A.; Becker, D.; Choi, S. K.; Datta, R.; Duff, S. M.; Gallardo, P. A.; Grace, E.; Wollack, E. J.

    2016-01-01

    The Atacama Cosmology Telescope Polarimeter (ACTPol) is a polarization sensitive receiver for the 6-meter Atacama Cosmology Telescope (ACT) and measures the small angular scale polarization anisotropies in the cosmic microwave background (CMB). The full focal plane is composed of three detector arrays, containing over 3000 transition edge sensors (TES detectors) in total. The first two detector arrays, observing at 146 gigahertz, were deployed in 2013 and 2014, respectively. The third and final array is composed of multichroic pixels sensitive to both 90 and 146 gigahertz and saw first light in February 2015. Fabricated at NIST, this dichroic array consists of 255 pixels, with a total of 1020 polarization sensitive bolometers and is coupled to the telescope with a monolithic array of broad-band silicon feedhorns. The detectors are read out using time-division SQUID multiplexing and cooled by a dilution refrigerator at 110 meter Kelvins. We present an overview of the assembly and characterization of this multichroic array in the lab, and the initial detector performance in Chile. The detector array has a TES detector electrical yield of 85 percent, a total array sensitivity of less than 10 microns Kelvin root mean square speed, and detector time constants and saturation powers suitable for ACT CMB observations.

  1. Stellar magnetic-field measurement with a double-beam polarimeter fitted with a photoelastic modulator.

    NASA Astrophysics Data System (ADS)

    Weiss, W.; Malanushenko, V. P.; Shakovskoj, N. M.

    Methods and apparatus are described for measuring the fields from hydrogen lines. The circular polarization in Hβ is measured with a double-beam polarimeter, which has two measurement channels, which operate the photon counting, and a control channel. In each channel, the light passes through the corresponding arms of a compound photoelastic modulator, which is excited by a crystal oscillator and which modulates the form of the polarization at 35 kHz. The signal from the control channel is used to switch the counters for the photomultiplier pulses in the measurement channels and to regulate the modulation amplitude. Interference filters with passbands of 6 Å are located in the measurement channels, with the passbands displaced by tilting the filters. The recording system is interfaced to the local computer network. Trial observations have been made on the magnetic fields of 4 Ap stars, and wide-band measurements have been made on the circular polarization of the polar AM Her. The method and apparatus give reliable measurements of fields of about 500 - 10000 Gauss for stars down to magnitude 7 - 8 and wide-band circular polarization measurements for fainter stars.

  2. Design of 280 GHz feedhorn-coupled TES arrays for the balloon-borne polarimeter SPIDER

    NASA Astrophysics Data System (ADS)

    Hubmayr, Johannes; Austermann, Jason E.; Beall, James A.; Becker, Daniel T.; Benton, Steven J.; Bergman, A. Stevie; Bond, J. Richard; Bryan, Sean; Duff, Shannon M.; Duivenvoorden, Adri J.; Eriksen, H. K.; Filippini, Jeffrey P.; Fraisse, A.; Galloway, Mathew; Gambrel, Anne E.; Ganga, K.; Grigorian, Arpi L.; Gualtieri, Riccardo; Gudmundsson, Jon E.; Hartley, John W.; Halpern, M.; Hilton, Gene C.; Jones, William C.; McMahon, Jeffrey J.; Moncelsi, Lorenzo; Nagy, Johanna M.; Netterfield, C. B.; Osherson, Benjamin; Padilla, Ivan; Rahlin, Alexandra S.; Racine, B.; Ruhl, John; Rudd, T. M.; Shariff, J. A.; Soler, J. D.; Song, Xue; Ullom, Joel N.; Van Lanen, Jeff; Vissers, Michael R.; Wehus, I. K.; Wen, Shyang; Wiebe, D. V.; Young, Edward

    2016-07-01

    We describe 280 GHz bolometric detector arrays that instrument the balloon-borne polarimeter spider. A primary science goal of spider is to measure the large-scale B-mode polarization of the cosmic microwave background (cmb) in search of the cosmic-inflation, gravitational-wave signature. 280 GHz channels aid this science goal by constraining the level of B-mode contamination from galactic dust emission. We present the focal plane unit design, which consists of a 16x16 array of conical, corrugated feedhorns coupled to a monolithic detector array fabricated on a 150 mm diameter silicon wafer. Detector arrays are capable of polarimetric sensing via waveguide probe-coupling to a multiplexed array of transition-edge-sensor (TES) bolometers. The spider receiver has three focal plane units at 280 GHz, which in total contains 765 spatial pixels and 1,530 polarization sensitive bolometers. By fabrication and measurement of single feedhorns, we demonstrate 14.7° FHWM Gaussian-shaped beams with <1% ellipticity in a 30% fractional bandwidth centered at 280 GHz. We present electromagnetic simulations of the detection circuit, which show 94% band-averaged, single-polarization coupling efficiency, 3% reflection and 3% radiative loss. Lastly, we demonstrate a low thermal conductance bolometer, which is well-described by a simple TES model and exhibits an electrical noise equivalent power (NEP) = 2.6 x 10-17 W/√Hz, consistent with the phonon noise prediction.

  3. New data acquisition system for the focal plane polarimeter of the Grand Raiden spectrometer

    SciTech Connect

    Tamii, A.; Sakaguchi, H.; Takeda, H.; Yosoi, M.; Akimune, H.; Fujiwara, M.; Ogata, H.; Tanaka, M.; Togawa, H.

    1996-10-01

    This paper describes a new data acquisition system for the focal plane polarimeter of the Grand Raiden spectrometer at the Research Center for Nuclear Physics (RCNP) in Osaka, Japan. Data are acquired by a Creative Electronic Systems (CES) Starburst, which is a CAMAC auxiliary crate controller equipped with a Digital Equipment Corporation (DEC) J11 microprocessor., The data on the Starburst are transferred to a VME single-board computer. A VME reflective memory module broadcasts the data to other systems through a fiber-optic link. A data transfer rate of 2.0 Mbytes/s between VME modules has been achieved by reflective memories. This rate includes the overhead of buffer management. The overall transfer rate, however, is limited by the performance of the Starburst to about 160 Kbytes/s at maximum. In order to further improve the system performance, the authors developed a new readout module called the Rapid Data Transfer Module (RDTM). RDTM`s transfer data from LeCroy PCOS III`s or 4298`s, and FERA/FERET`s directly to CES 8170 High Speed Memories (HSM) in VME crates. The data transfer rate of the RDTM from PCOS III`s to the HSM is about 4 Mbytes/s.

  4. Characterization and initial results from the upgraded MST interferometer-polarimeter

    NASA Astrophysics Data System (ADS)

    Parke, E.; Brower, D. L.; Ding, W. X.; Duff, J. R.

    2015-11-01

    The FIR interferometer-polarimeter diagnostic on MST is a high-bandwidth system with unique capabilities for measuring high-frequency density and internal magnetic fluctuations. Installation of new planar-diode mixers improves both the signal strength and the noise floor compared to the corner-cube mixers previously used. The new mixer technology also offers a simpler detection configuration that eliminates the need for additional amplifiers. We characterize the bandwidth capabilities of the upgraded heterodyne receiver system and present initial measurements in reversed-field pinch (RFP) plasmas. High wavenumber resolution becomes possible when operating without focusing elements, using only the 2-3 mm aperture on the mixer to determine the sampled chord width. This configuration will provide better resolution of small-scale fluctuations observed in the RFP during periods of improved, tokamak-like confinement. Finally, cross-correlation techniques between two mixers viewing the same chord further reduce measurement noise and improve the resolution of high-frequency, small-amplitude magnetic and density fluctuations. Initial tests of this technique in neutral-beam heated plasmas will be presented. Work supported by U.S. DOE.

  5. Characterization and initial results from the upgraded MST interferometer-polarimeter

    NASA Astrophysics Data System (ADS)

    Ding, W. X.; Parke, E.; Brower, D. L.; Duff, J.

    2016-10-01

    The FIR interferometer-polarimeter diagnostic on MST is a high-bandwidth system with unique capabilities for measuring high-frequency density and internal magnetic fluctuations. Installation of new planar-diode mixers improves both the signal strength and the noise floor compared to the corner-cube mixers previously used. Measurements of density and Faraday rotation angle in standard reversed-field pinch (RFP) plasmas and plasmas with improved, tokamak-like confinement are presented. The noise floor in the Faraday rotation power spectrum is reduced by nearly an order of magnitude, with fluctuations observed up to 250 kHz. Cross-correlation between multiple mixers is an additional, novel technique for reducing the noise floor and improving the resolution of high-frequency, small-amplitude magnetic and density fluctuations. Correlation of signals from two independent mixers viewing the same chord reduces the noise floor by another order of magnitude. High wavenumber resolution may be possible when operating without focusing elements, using only the 2-3 mm aperture on the mixer to determine the sampled chord width. This configuration will provide better resolution of small-scale fluctuations observed in the RFP during periods of improved confinement. Work supported by U.S. D.O.E.

  6. Accuracy Assessments of Cloud Droplet Size Retrievals from Polarized Reflectance Measurements by the Research Scanning Polarimeter

    NASA Technical Reports Server (NTRS)

    Alexandrov, Mikhail Dmitrievic; Cairns, Brian; Emde, Claudia; Ackerman, Andrew S.; vanDiedenhove, Bastiaan

    2012-01-01

    We present an algorithm for the retrieval of cloud droplet size distribution parameters (effective radius and variance) from the Research Scanning Polarimeter (RSP) measurements. The RSP is an airborne prototype for the Aerosol Polarimetery Sensor (APS), which was on-board of the NASA Glory satellite. This instrument measures both polarized and total reflectance in 9 spectral channels with central wavelengths ranging from 410 to 2260 nm. The cloud droplet size retrievals use the polarized reflectance in the scattering angle range between 135deg and 165deg, where they exhibit the sharply defined structure known as the rain- or cloud-bow. The shape of the rainbow is determined mainly by the single scattering properties of cloud particles. This significantly simplifies both forward modeling and inversions, while also substantially reducing uncertainties caused by the aerosol loading and possible presence of undetected clouds nearby. In this study we present the accuracy evaluation of our algorithm based on the results of sensitivity tests performed using realistic simulated cloud radiation fields.

  7. Performance Characterization of the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) CCD Cameras

    NASA Technical Reports Server (NTRS)

    Joiner, Reyann; Kobayashi, Ken; Winebarger, Amy; Champey, Patrick

    2014-01-01

    The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) is a sounding rocket instrument which is currently being developed by NASA's Marshall Space Flight Center (MSFC) and the National Astronomical Observatory of Japan (NAOJ). The goal of this instrument is to observe and detect the Hanle effect in the scattered Lyman-Alpha UV (121.6nm) light emitted by the Sun's Chromosphere to make measurements of the magnetic field in this region. In order to make accurate measurements of this effect, the performance characteristics of the three on-board charge-coupled devices (CCDs) must meet certain requirements. These characteristics include: quantum efficiency, gain, dark current, noise, and linearity. Each of these must meet predetermined requirements in order to achieve satisfactory performance for the mission. The cameras must be able to operate with a gain of no greater than 2 e(-)/DN, a noise level less than 25e(-), a dark current level which is less than 10e(-)/pixel/s, and a residual nonlinearity of less than 1%. Determining these characteristics involves performing a series of tests with each of the cameras in a high vacuum environment. Here we present the methods and results of each of these performance tests for the CLASP flight cameras.

  8. A Sounding Rocket Experiment for the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP)

    NASA Technical Reports Server (NTRS)

    Kubo, M.; Kano, R.; Kobayashi, K.; Ishikawa, R.; Bando, T.; Narukage, N.; Katsukawa, Y.; Ishikawa, S.; Suematsu, Y.; Hara, H.; Tsuneta, S.; Shimizu, T.; Sakao, T.; Ichimoto, K.; Winebarger, A.; Cirtain, J.; De Pontieu, B.; Casini, R.; Auchere, F.; Trujillo, Bueno J.; Manso, Sainz R.; Ramos, Asensio A.; Stepan, J.; Belluzi, L.; Carlsson, M.

    2014-01-01

    A sounding-rocket experiment called the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) is presently under development to measure the linear polarization profiles caused by scattering processes and the Hanle effect in the hydrogen Lyman-alpha line (121.567nm). Accurate measurements of the linear polarization signals caused by scattering processes and the Hanle effect are essential to explore the strength and structures of weak magnetic fields. The primary target of future solar telescopes is to measure the weak magnetic field in outer solar atmospheres (from the chromosphere to the corona through the transition region). The hydrogen Lyman-alpha-line is one of the best lines for the diagnostics of magnetic fields in the outer solar atmospheres. CLASP is to be launched in 2015, and will provide, for the first time, the observations required for magnetic field measurements in the upper chromosphere and transition region. CLASP is designed to have a polarimetric sensitivity of 0.1% and a spectral resolution of 0.01nm for the Lyman-alpha line. CLASP will measure two orthogonal polarizations simultaneously for about 5-minute flight. Now the integration of flight mirrors and structures is in progress. In addition to our strategy to realize such a high-precision spectro-polarimetry in the UV, we will present a progress report on our pre-launch evaluation of optical and polarimetric performances of CLASP.

  9. The First Multichroic Polarimeter Array on the Atacama Cosmology Telescope: Characterization and Performance

    NASA Astrophysics Data System (ADS)

    Ho, S. P.; Pappas, C. G.; Austermann, J.; Beall, J. A.; Becker, D.; Choi, S. K.; Datta, R.; Duff, S. M.; Gallardo, P. A.; Grace, E.; Hasselfield, M.; Henderson, S. W.; Hilton, G. C.; Hubmayr, J.; Koopman, B. J.; Lanen, J. V.; Li, D.; McMahon, J.; Nati, F.; Niemack, M. D.; Niraula, P.; Salatino, M.; Schillaci, A.; Schmitt, B. L.; Simon, S. M.; Staggs, S. T.; Stevens, J. R.; Ward, J. T.; Wollack, E. J.; Vavagiakis, E. M.

    2016-08-01

    The Atacama Cosmology Telescope Polarimeter (ACTPol) is a polarization sensitive receiver for the 6-m Atacama Cosmology Telescope (ACT) and measures the small angular scale polarization anisotropies in the cosmic microwave background (CMB). The full focal plane is composed of three detector arrays, containing over 3000 transition edge sensors (TES detectors) in total. The first two detector arrays, observing at 146 GHz, were deployed in 2013 and 2014, respectively. The third and final array is composed of multichroic pixels sensitive to both 90 and 146 GHz and saw first light in February 2015. Fabricated at NIST, this dichroic array consists of 255 pixels, with a total of 1020 polarization sensitive bolometers and is coupled to the telescope with a monolithic array of broad-band silicon feedhorns. The detectors are read out using time-division SQUID multiplexing and cooled by a dilution refrigerator at 110 mK. We present an overview of the assembly and characterization of this multichroic array in the lab, and the initial detector performance in Chile. The detector array has a TES detector electrical yield of 85 %, a total array sensitivity of less than 10 \\upmu K√{ {s}}, and detector time constants and saturation powers suitable for ACT CMB observations.

  10. Faraday-Effect Polarimeter-Interferometer System for current density measurement on EAST

    NASA Astrophysics Data System (ADS)

    Liu, Haiqing; Jie, Yinxian; Ding, Weixing; Brower, David Lyn; Zou, Zhiyong; Qian, Jinping; Li, Weiming; Zeng, Long; Zhang, Shoubiao; Hu, Liqun; Wan, Baonian

    2015-11-01

    An eleven-channel far-infrared laser-based POlarimeter-INTerferometer (POINT) system utilizing the three-wave technique has been implemented for current density and electron density profile measurements in the EAST tokamak. Both polarimetric and interferometric measurement are obtained in a long pulse (~ 52s) discharge. The electron line-integrated density resolution of POINT is less than 5 × 1016 m-2 (~ 2°), and the Faraday rotation angle rms phase noise is <0.1°. With the high temporal (~ 1 μsec) and phase resolution (<0.1°), density perturbations associated with the sawteeth cycle and tearing mode activities have been observed. It is evident that tearing modes are well correlated to dynamics of equilibrium current profile (or q-profile). Faraday rotation angle shows clear variation with low hybrid current drive while line-integrated density remains little changed, implying the current drive in the core. A Digital Phase Detector with 250 kHz bandwidth provides real-time Faraday rotation angle and density phase shift output, which will be integrated into current profile control system in a long pulse discharge in future. This work is supported by the National Magnetic Confinement Fusion Program of China with contract No. 2012GB101002 and partly supported by the US D.O.E. contract DESC0010469.

  11. Faraday-Effect Polarimeter Diagnostic for Internal Magnetic Field Fluctuation Measurements in DIII-D

    NASA Astrophysics Data System (ADS)

    Chen, Jie; Ding, W. X.; Brower, D. L.

    2015-11-01

    A high-resolution Faraday-effect polarimeter-interferometer diagnostic currently under construction at the DIII-D tokamak has three overall measurement goals: (1) determine the current density dynamics at the magnetic axis, J(0,t), for torque-free plasmas (no NBI) and bootstrap current in the pedestal region; (2) resolve both coherent and broadband magnetic fluctuations [at the level δb <= 1 Gauss with up to 2 MHz bandwidth] associated with MHD perturbations, energetic particle driven modes and broadband turbulence (e.g. microtearing modes), and (3) identify non-axisymmetric structures and plasma response to externally applied RMP (resonant magnetic perturbation) fields being developed for ELM control as well as MHD events. These goals will be achieved using a 650-700 GHz source and heterodyne receiver system to measure the line-integrated Faraday-effect and density along three horizontal chords positioned at the magnetic axis and +/-15 cm off-axis. The system will be double-pass and cornercube retroreflectors have already been installed. Simultaneous measurement of density and Faraday effect allows isolation of the fluctuating magnetic field component in the radial direction. Supported by US DOE under DE-FG03-01ER54615 and DE-FC02-04ER54698.

  12. Performance Characterization of the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) CCD Cameras

    NASA Technical Reports Server (NTRS)

    Joiner, Reyann; Kobayashi, Ken; Winebarger, Amy; Champey, Patrick

    2014-01-01

    The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) is a sounding rocket instrument currently being developed by NASA's Marshall Space Flight Center (MSFC), the National Astronomical Observatory of Japan (NAOJ), and other partners. The goal of this instrument is to observe and detect the Hanle effect in the scattered Lyman-Alpha UV (121.6nm) light emitted by the Sun's chromosphere. The polarized spectrum imaged by the CCD cameras will capture information about the local magnetic field, allowing for measurements of magnetic strength and structure. In order to make accurate measurements of this effect, the performance characteristics of the three on- board charge-coupled devices (CCDs) must meet certain requirements. These characteristics include: quantum efficiency, gain, dark current, read noise, and linearity. Each of these must meet predetermined requirements in order to achieve satisfactory performance for the mission. The cameras must be able to operate with a gain of 2.0+/- 0.5 e--/DN, a read noise level less than 25e-, a dark current level which is less than 10e-/pixel/s, and a residual non- linearity of less than 1%. Determining these characteristics involves performing a series of tests with each of the cameras in a high vacuum environment. Here we present the methods and results of each of these performance tests for the CLASP flight cameras.

  13. The Stokes-Einstein relation at moderate Schmidt number.

    PubMed

    Balboa Usabiaga, Florencio; Xie, Xiaoyi; Delgado-Buscalioni, Rafael; Donev, Aleksandar

    2013-12-07

    The Stokes-Einstein relation for the self-diffusion coefficient of a spherical particle suspended in an incompressible fluid is an asymptotic result in the limit of large Schmidt number, that is, when momentum diffuses much faster than the particle. When the Schmidt number is moderate, which happens in most particle methods for hydrodynamics, deviations from the Stokes-Einstein prediction are expected. We study these corrections computationally using a recently developed minimally resolved method for coupling particles to an incompressible fluctuating fluid in both two and three dimensions. We find that for moderate Schmidt numbers the diffusion coefficient is reduced relative to the Stokes-Einstein prediction by an amount inversely proportional to the Schmidt number in both two and three dimensions. We find, however, that the Einstein formula is obeyed at all Schmidt numbers, consistent with linear response theory. The mismatch arises because thermal fluctuations affect the drag coefficient for a particle due to the nonlinear nature of the fluid-particle coupling. The numerical data are in good agreement with an approximate self-consistent theory, which can be used to estimate finite-Schmidt number corrections in a variety of methods. Our results indicate that the corrections to the Stokes-Einstein formula come primarily from the fact that the particle itself diffuses together with the momentum. Our study separates effects coming from corrections to no-slip hydrodynamics from those of finite separation of time scales, allowing for a better understanding of widely observed deviations from the Stokes-Einstein prediction in particle methods such as molecular dynamics.

  14. Colles-Stokes contributions to the concept of heart failure.

    PubMed

    Ventura, H O; Mehra, M R

    1998-06-15

    "Colles fracture," "Colles law," "Stokes-Adams syndrome," "Cheyne-Stokes respiration," and "Corrigan pulse" are some of the contributions of the Irish school that are utilized for teaching purposes in medical schools and training programs, as well as in daily practice of medicine. We wish to add an important description by Drs. Colles and Stokes that personifies the considerable personal contributions of these 2 physicians in our understanding of the pathophysiologic expression of the syndrome of heart failure. The clinical-pathologic correlation of the disease that affected Dr. Colles is well described by Dr. Stokes in his treatise Diseases of the Heart and the Aorta. He recognized the cyclical nature of frequent decompensations in heart failure, the relation of clinical worsening in conjunction with reduced urine output, as well as the importance of reestablishing urinary flow to achieve a decrease in dyspnea. Dr. Colles also demonstrated a profound clinical insight when he noticed, first, that his affliction was "eventually a fatal disease and that remedies that work may lose effect over time," illustrating an observation that has stood the test of time and, secondly, when he told Dr. Smith "... I would direct particular attention to the heart and the lungs ... and the swelling in the right hypochondrium ... I suspect that there is some connexion between this swelling of the hypochondrium and the diseased state of the heart." We believe that the Colles-Stokes contributions, both in the clinical as well as the clinical-pathologic arenas, are one of the landmark descriptions that helped to evolve the concept of the syndrome of heart failure.

  15. Well-Posed Stokes/Brinkman and Stokes/Darcy Problems for Coupled Fluid-Porous Viscous Flows

    NASA Astrophysics Data System (ADS)

    Angot, Philippe

    2010-09-01

    We present a well-posed model for the Stokes/Brinkman problem with a family of jump embedded boundary conditions (J.E.B.C.) on an immersed interface with weak regularity assumptions. It is issued from a general framework recently proposed for fictitious domain problems. Our model is based on algebraic transmission conditions combining the stress and velocity jumps on the interface Σ separating the fluid and porous domains. These conditions, well chosen to get the coercivity of the operator, are sufficiently general to get the usual immersed boundary conditions on Σ when fictitious domain methods are concerned: Stefan-like, Robin (Fourier), Neumann or Dirichlet… Moreover, the general framework allows to prove the global solvability of some models with physically relevant stress or velocity jump boundary conditions for the momentum transport at a fluid-porous interface. The Stokes/Brinkman problem with Ochoa-Tapia & Whitaker (1995) interface conditions and the Stokes/Darcy problem with Beavers & Joseph (1967) conditions are both proved to be well-posed by an asymptotic analysis. Up to our knowledge, only the Stokes/Darcy problem with Saffman (1971) approximate interface conditions was known to be well-posed.

  16. Use of the Gerchberg-Saxton algorithm in optimal coherent anti-Stokes Raman spectroscopy.

    PubMed

    Moore, D S; McGrane, S D; Greenfield, M T; Scharff, R J; Chalmers, R E

    2012-01-01

    We are utilizing recent advances in ultrafast laser technology and recent discoveries in optimal shaping of laser pulses to significantly enhance the stand-off detection of explosives via control of molecular processes at the quantum level. Optimal dynamic detection of explosives is a method whereby the selectivity and sensitivity of any of a number of nonlinear spectroscopic methods are enhanced using optimal shaping of ultrafast laser pulses. We have recently investigated the Gerchberg-Saxton algorithm as a method to very quickly estimate the optimal spectral phase for a given analyte from its spontaneous Raman spectrum and the ultrafast laser pulse spectrum. Results for obtaining selective coherent anti-Stokes Raman spectra (CARS) for an analyte in a mixture, while suppressing the CARS signals from the other mixture components, are compared for the Gerchberg-Saxton method versus previously obtained results from closed-loop machine-learning optimization using evolutionary strategies.

  17. Prediction of viscous ship roll damping by unsteady Navier-Stokes techniques

    SciTech Connect

    Korpus, R.A.; Falzarano, J.M.

    1996-12-31

    This paper describes a numerical technique for analyzing the viscous unsteady flow around oscillating ship hulls. The technique is based on a general Reynolds-Averaged Navier-Stokes (RANS) capability, and is intended to generate viscous roll moment data for the incorporation of real-flow effects into potential flow ship motions programs. The approach utilizes the Finite Analytic technique for discretizing the unsteady RANS equations, and a variety of advanced turbulence models for closure. The calculations presented herein focus on viscous and vortical effects without free-surface, and utilize {kappa}{epsilon} turbulence modeling. Series variations are presented to study the effects of frequency, amplitude, Reynolds number, and the presence of bilge keels. Moment component breakdown studies are performed in each case to isolate the effects of viscosity, vorticity, and potential flow pressures.

  18. Turbine Internal and Film Cooling Modeling For 3D Navier-Stokes Codes

    NASA Technical Reports Server (NTRS)

    DeWitt, Kenneth; Garg Vijay; Ameri, Ali

    2005-01-01

    The aim of this research project is to make use of NASA Glenn on-site computational facilities in order to develop, validate and apply aerodynamic, heat transfer, and turbine cooling models for use in advanced 3D Navier-Stokes Computational Fluid Dynamics (CFD) codes such as the Glenn-" code. Specific areas of effort include: Application of the Glenn-HT code to specific configurations made available under Turbine Based Combined Cycle (TBCC), and Ultra Efficient Engine Technology (UEET) projects. Validating the use of a multi-block code for the time accurate computation of the detailed flow and heat transfer of cooled turbine airfoils. The goal of the current research is to improve the predictive ability of the Glenn-HT code. This will enable one to design more efficient turbine components for both aviation and power generation. The models will be tested against specific configurations provided by NASA Glenn.

  19. Balloon-Borne Gamma-Ray Polarimeter (PoGO) to Study Black Holes, Pulsars, and AGN Jets: Design and Calibration(SULI)

    SciTech Connect

    Apte, Zachary; /Hampshire Coll. /SLAC

    2005-12-15

    Polarization measurements at X-ray and gamma-ray energies can provide crucial information on the emission region around massive compact objects such as black holes and neutron stars. The Polarized Gamma-ray Observer (PoGO) is a new balloon-borne instrument designed to measure polarization from such astrophysical objects in the 30-100 keV range, under development by an international collaboration with members from United States, Japan, Sweden and France. The PoGO instrument has been designed by the collaboration and several versions of prototype models have been built at SLAC. The purpose of this experiment is to test the latest prototype model with a radioactive gamma-ray source. For this, we have to polarize gamma-rays in a laboratory environment. Unpolarized gamma-rays from Am241 (59.5 keV) were Compton scattered at around 90 degrees for this purpose. Computer simulation of the scattering process in the setup predicts a 86% polarization. The polarized beam was then used to irradiate the prototype PoGO detector. The data taken in this experiment showed a clear polarization signal, with a measured azimuthal modulation factor of 0.35 {+-} 0.02. The measured modulation is in very close agreement with the value expected from a previous beam test study of a polarized gamma-ray beam at the Argonne National Laboratories Advanced Photon Source. This experiment has demonstrated that the PoGO instrument (or any other polarimeter in the energy range) can be tested in a libratory with a simple setup to a similar accuracy.

  20. Performance Characterization of UV Science Cameras Developed for the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP)

    NASA Technical Reports Server (NTRS)

    Champey, Patrick; Kobayashi, Ken; Winebarger, Amy; Cirtin, Jonathan; Hyde, David; Robertson, Bryan; Beabout, Brent; Beabout, Dyana; Stewart, Mike

    2014-01-01

    The NASA Marshall Space Flight Center (MSFC) has developed a science camera suitable for sub-orbital missions for observations in the UV, EUV and soft X-ray. Six cameras will be built and tested for flight with the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP), a joint National Astronomical Observatory of Japan (NAOJ) and MSFC sounding rocket mission. The goal of the CLASP mission is to observe the scattering polarization in Lyman-alpha and to detect the Hanle effect in the line core. Due to the nature of Lyman-alpha polarization in the chromosphere, strict measurement sensitivity requirements are imposed on the CLASP polarimeter and spectrograph systems; science requirements for polarization measurements of Q/I and U/I are 0.1% in the line core. CLASP is a dual-beam spectro-polarimeter, which uses a continuously rotating waveplate as a polarization modulator, while the waveplate motor driver outputs trigger pulses to synchronize the exposures. The CCDs are operated in frame-transfer mode; the trigger pulse initiates the frame transfer, effectively ending the ongoing exposure and starting the next. The strict requirement of 0.1% polarization accuracy is met by using frame-transfer cameras to maximize the duty cycle in order to minimize photon noise. Coating the e2v CCD57-10 512x512 detectors with Lumogen-E coating allows for a relatively high (30%) quantum efficiency at the Lyman-$\\alpha$ line. The CLASP cameras were designed to operate with =10 e- /pixel/second dark current, = 25 e- read noise, a gain of 2.0 and =0.1% residual non-linearity. We present the results of the performance characterization study performed on the CLASP prototype camera; dark current, read noise, camera gain and residual non-linearity.

  1. A crosstalk and non-uniformity correction method for the space-borne Compton polarimeter POLAR

    NASA Astrophysics Data System (ADS)

    Xiao, Hualin; Hajdas, Wojtek; Wu, Bobing; Produit, Nicolas; Bao, Tianwei; Batsch, Tadeusz; Cadoux, Franck; Chai, Junying; Dong, Yongwei; Kong, Minnan; Kong, Siwei; Rybka, Dominik K.; Leluc, Catherine; Li, Lu; Liu, Jiangtao; Liu, Xin; Marcinkowski, Radoslaw; Paniccia, Mercedes; Pohl, Martin; Rapin, Divic; Shi, Haoli; Song, Liming; Sun, Jianchao; Szabelski, Jacek; Wang, Ruijie; Wen, Xing; Xu, Hanhui; Zhang, Laiyu; Zhang, Li; Zhang, Shuangnan; Zhang, Xiaofeng; Zhang, Yongjie; Zwolinska, Ania

    2016-10-01

    In spite of extensive observations and numerous theoretical studies in the past decades several key questions related with Gamma-Ray Bursts (GRB) emission mechanisms are still to be answered. Precise detection of the GRB polarization carried out by dedicated instruments can provide new data and be an ultimate tool to unveil their real nature. A novel space-borne Compton polarimeter POLAR onboard the Chinese space station TG2 is designed to measure linear polarization of gamma-rays arriving from GRB prompt emissions. POLAR uses plastics scintillator bars (PS) as gamma-ray detectors and multi-anode photomultipliers (MAPMTs) for readout of the scintillation light. Inherent properties of such detection systems are crosstalk and non-uniformity. The crosstalk smears recorded energy over multiple channels making both non-uniformity corrections and energy calibration more difficult. Rigorous extraction of polarization observables requires to take such effects properly into account. We studied influence of the crosstalk on energy depositions during laboratory measurements with X-ray beams. A relation between genuine and recorded energy was deduced using an introduced model of data analysis. It postulates that both the crosstalk and non-uniformities can be described with a single matrix obtained in calibrations with mono-energetic X- and gamma-rays. Necessary corrections are introduced using matrix based equations allowing for proper evaluation of the measured GRB spectra. Validity of the method was established during dedicated experimental tests. The same approach can be also applied in space utilizing POLAR internal calibration sources. The introduced model is general and with some adjustments well suitable for data analysis from other MAPMT-based instruments.

  2. Conceptual design of the tangentially viewing combined interferometer-polarimeter for ITER density measurements

    NASA Astrophysics Data System (ADS)

    Van Zeeland, M. A.; Boivin, R. L.; Brower, D. L.; Carlstrom, T. N.; Chavez, J. A.; Ding, W. X.; Feder, R.; Johnson, D.; Lin, L.; O'Neill, R. C.; Watts, C.

    2013-04-01

    One of the systems planned for the measurement of electron density in ITER is a multi-channel tangentially viewing combined interferometer-polarimeter (TIP). This work discusses the current status of the design, including a preliminary optical table layout, calibration options, error sources, and performance projections based on a CO2/CO laser system. In the current design, two-color interferometry is carried out at 10.59 μm and 5.42 μm and a separate polarimetry measurement of the plasma induced Faraday effect, utilizing the rotating wave technique, is made at 10.59 μm. The inclusion of polarimetry provides an independent measure of the electron density and can also be used to correct the conventional two-color interferometer for fringe skips at all densities, up to and beyond the Greenwald limit. The system features five chords with independent first mirrors to reduce risks associated with deposition, erosion, etc., and a common first wall hole to minimize penetration sizes. Simulations of performance for a projected ITER baseline discharge show the diagnostic will function as well as, or better than, comparable existing systems for feedback density control. Calculations also show that finite temperature effects will be significant in ITER even for moderate temperature plasmas and can lead to a significant underestimate of electron density. A secondary role TIP will fulfill is that of a density fluctuation diagnostic; using a toroidal Alfvén eigenmode as an example, simulations show TIP will be extremely robust in this capacity and potentially able to resolve coherent mode fluctuations with perturbed densities as low as δn/n ≈ 10-5.

  3. Design of far-infrared polarimeter/interferometer system for EAST tokamak

    NASA Astrophysics Data System (ADS)

    Liu, H. Q.; Jie, Y. X.; Ding, W. X.; Brower, D. L.; Zou, Z. Y.; Wang, Z. X.; Yang, Y.; Qian, J. P.; Zeng, L.; Wei, X. C.; Shen, J. S.; An, Z. H.; Lan, T.; Wang, H. B.

    2013-11-01

    A double-pass, radially-viewing, multichannel far-infrared (FIR) polarimeter/interferometer system is under development for current density profile and electron density profile measurements in the EAST tokamak. The system utilizes three 432.5 μm CW formic acid FIR lasers pumped by three CO2 lasers. Each of the three FIR lasers can generate high output power of more than 30 mW per cavity. Two lasers, with slight frequency offset ( ~ 1 MHz), will be made collinear with counter-rotating circular polarization in order to determine the Faraday effect by measuring their phase difference. The third laser also frequency offset, will be used as a reference providing local oscillator (LO) power to each mixer so that one can obtain the phase shift caused by the plasma electron density. Novel molybdenic retro-reflectors with shutter protection have been designed and will be mounted on the inner vessel wall in EAST. The retro-reflectors can withstand baking temperature up to 350°C and discharge duration more than 1000 s. Vibrations and path length changes due to thermal expansion will be compensated using a He-Ne interferometer as the second color. VDI planar-diode Integrated Conical Horn Fundamental Mixers optimized for high sensitivity, typical 750 V/W, will be used. Initially a five-chord system will be installed in 2013 and an eleven-chord system will be implemented on the core region of EAST plasmas. MHz frequency response allows system to resolve fast MHD events such as tearing/neoclassical tearing, disruptions and fast-particle modes. Preliminary design will be presented.

  4. Preliminary Neutronics Analysis of the ITER Toroidal Interferometer and Polarimeter Diagnostic Corner Cube Retroreflectors

    SciTech Connect

    Tresemer, K. R.

    2015-07-01

    ITER is an international project under construction in France that will demonstrate nuclear fusion at a power plant-relevant scale. The Toroidal Interferometer and Polarimeter (TIP) Diagnostic will be used to measure the plasma electron line density along 5 laser-beam chords. This line-averaged density measurement will be input to the ITER feedback-control system. The TIP is considered the primary diagnostic for these measurements, which are needed for basic ITER machine control. Therefore, system reliability & accuracy is a critical element in TIP’s design. There are two major challenges to the reliability of the TIP system. First is the survivability and performance of in-vessel optics and second is maintaining optical alignment over long optical paths and large vessel movements. Both of these issues greatly depend on minimizing the overall distortion due to neutron & gamma heating of the Corner Cube Retroreflectors (CCRs). These are small optical mirrors embedded in five first wall locations around the vacuum vessel, corresponding to certain plasma tangency radii. During the development of the design and location of these CCRs, several iterations of neutronics analyses were performed to determine and minimize the total distortion due to nuclear heating of the CCRs. The CCR corresponding to TIP Channel 2 was chosen for analysis as a good middle-road case, being an average distance from the plasma (of the five channels) and having moderate neutron shielding from its blanket shield housing. Results show that Channel 2 meets the requirements of the TIP Diagnostic, but barely. These results suggest other CCRs might be at risk of exceeding thermal deformation due to nuclear heating.

  5. QUaD: A millimeter-wave polarimeter for observation of the cosmic microwave background radiation

    NASA Astrophysics Data System (ADS)

    Hinderks, James R.

    2005-11-01

    This thesis describes the design and performance of the QUaD experiment and presents some of its earliest results. QUaD is a millimeter-wavelength polarimeter designed for observing the Cosmic Microwave Background (CMB). QUaD was commissioned at the MAPO observatory at the Amundsen-Scott South Pole Station in the Austral Summer of 2004/2005, achieved first light in Feb 2005, and began science observation in May. QUaD observes the CMB with an array of 31 polarization-sensitive Neutron Transmutation Doped (NTD) germanium bolometers split between two frequency bands centered at 100 and 150 GHz. The telescope is a 2.6 m on-axis Cassegrain design with beam sizes of 6.3' and 4.2' at the two respective observing frequencies. The resolution and scan strategy are optimized to probe the CMB E- mode power spectrum over a multipole range of 100 to 2500. The performance of the system has been characterized with commissioning observations and a high signal-to-noise map of the CMB temperature anisotropy has been made over a ~50 square degree area. CMB polarization anisotropies, only recently detected, promise a wealth of new cosmological information. Their observation complements the many successful temperature anisotropy measurements already performed, confirming our basic understanding of the early universe and leading to tighter constraints on cosmological parameters. Furthermore, polarization observations provide a probe of structure since the last scattering surface and promise unique constraints on inflation through the imprint of relict gravitational radiation.

  6. Characterization of Detectors and Instrument Systematics for the SPIDER CMB Polarimeter

    NASA Astrophysics Data System (ADS)

    Tucker, Rebecca Suzanne

    We know from the CMB and observations of large-scale structure that the universe is extremely flat, homogenous, and isotropic. The current favored mechanism for generating these characteristics is inflation, a theorized period of exponential expansion of the universe that occurred shortly after the Big Bang. Most theories of inflation generically predict a background of stochastic gravitational waves. These gravitational waves should leave their unique imprint on the polarization of the CMB via Thompson scattering. Scalar perturbations of the metric will cause a pattern of polarization with no curl (E-mode). Tensor perturbations (gravitational waves) will cause a unique pattern of polarization on the CMB that includes a curl component (B-mode). A measurement of the ratio of the tensor to scalar perturbations (r ) tells us the energy scale of inflation. Recent measurements by the BICEP2 team detect the B-mode spectrum with a tensor-to-scalar ratio of r=0.2 (+0.05, -0.07). An independent confirmation of this result is the next step towards understanding the inflationary universe. This thesis describes my work on a balloon-borne polarimeter called SPIDER, which is designed to illuminate the physics of the early universe through measurements of the cosmic microwave background polarization. SPIDER consists of six single-frequency, on-axis refracting telescopes contained in a shared-vacuum liquid-helium cryostat. Its large format arrays of millimeter-wave detectors and tight control of systematics will give it unprecedented sensitivity. This thesis describes how the SPIDER detectors are characterized and calibrated for flight, as well as how the systematics requirements for the SPIDER system are simulated and measured.

  7. Remote Sensing of Cloud Top Heights Using the Research Scanning Polarimeter

    NASA Technical Reports Server (NTRS)

    Sinclair, Kenneth; van Diedenhoven, Bastiaan; Cairns, Brian; Yorks, John; Wasilewski, Andrzej

    2015-01-01

    Clouds cover roughly two thirds of the globe and act as an important regulator of Earth's radiation budget. Of these, multilayered clouds occur about half of the time and are predominantly two-layered. Changes in cloud top height (CTH) have been predicted by models to have a globally averaged positive feedback, however observational changes in CTH have shown uncertain results. Additional CTH observations are necessary to better and quantify the effect. Improved CTH observations will also allow for improved sub-grid parameterizations in large-scale models and accurate CTH information is important when studying variations in freezing point and cloud microphysics. NASA's airborne Research Scanning Polarimeter (RSP) is able to measure cloud top height using a novel multi-angular contrast approach. RSP scans along the aircraft track and obtains measurements at 152 viewing angles at any aircraft location. The approach presented here aggregates measurements from multiple scans to a single location at cloud altitude using a correlation function designed to identify the location-distinct features in each scan. During NASAs SEAC4RS air campaign, the RSP was mounted on the ER-2 aircraft along with the Cloud Physics Lidar (CPL), which made simultaneous measurements of CTH. The RSPs unique method of determining CTH is presented. The capabilities of using single and combinations of channels within the approach are investigated. A detailed comparison of RSP retrieved CTHs with those of CPL reveal the accuracy of the approach. Results indicate a strong ability for the RSP to accurately identify cloud heights. Interestingly, the analysis reveals an ability for the approach to identify multiple cloud layers in a single scene and estimate the CTH of each layer. Capabilities and limitations of identifying single and multiple cloud layers heights are explored. Special focus is given to sources of error in the method including optically thin clouds, physically thick clouds, multi

  8. Development of a dedicated readout ASIC for TPC based X-ray polarimeter

    NASA Astrophysics Data System (ADS)

    Zhang, Hongyan; Deng, Zhi; Li, Hong; Liu, Yinong; Feng, Hua

    2016-07-01

    X-ray polarimetry with time projection chambers was firstly proposed by JK Black in 2007 and has been greatly developed since then. It measured two dimensional photoelectron tracks with one dimensional strip and the other dimension was estimated by the drift time from the signal waveforms. A readout ASIC, APV25, originally developed for CMS silicon trackers was used and has shown some limitations such as waveform sampling depth. A dedicated ASIC was developed for TPC based X-ray polarimeters in this paper. It integrated 32 channel circuits and each channel consisted of an analog front-end and a waveform sampler based on switched capacitor array. The analog front-end has a charge sensitive preamplifier with a gain of 25 mV/fC, a CR-RC shaper with a peaking time of 25 ns, a baseline holder and a discriminator for self-triggering. The SCA has a buffer latency of 3.2 μs with 64 cells operating at 20 MSPS. The ASIC was fabricated in a 0.18 μm CMOS process. The equivalent noise charge (ENC) of the analog front-end was measured to be 274.8 e+34.6 e/pF. The effective resolution of the SCA was 8.8 bits at sampling rate up to 50 MSPS. The total power consumption was 2.8 mW per channel. The ASIC was also tested with real TPC detectors and two dimensional photoelectron tracks have been successfully acquired. More tests and analysis on the sensitivity to the polarimetry are undergoing and will be presented in this paper.

  9. Internal magnetic field measurements by laser-based POlarimeter-INTerferometer (POINT) system on EAST

    NASA Astrophysics Data System (ADS)

    Liu, H. Q.; Jie, Y. X.; Ding, W. X.; Brower, D. L.; Zou, Z. Y.; Qian, J. P.; Li, W. M.; Yang, Y.; Zeng, L.; Zhang, S. B.; Lan, T.; Wang, S. X.; Hanada, K.; Wei, X. C.; Hu, L. Q.; Wan, B. N.

    2016-01-01

    A multi-channel far-infrared laser-based POlarimeter-INTerferometer (POINT) system utilizing the three-wave technique has been implemented for fully diagnosing the internal magnetic field in the EAST tokamak. Double-pass, horizontal, radially-viewing chords access the plasma via an equatorial port. The laser source consists of three CW formic acid (HCOOH) FIR lasers at nominal wavelength 432.5 μm which are optically pumped by independent infrared CO2 lasers. Output power is more than 30 mW of per cavity. Novel molybdenum retro-reflectors, can with withstand baking temperature up to 350°C and discharge duration more than 1000 s, are mounted in the inside wall for the double-pass optical arrangement. A Digital Phase Detector with 250 kHz bandwidth, which provide real-time Faraday rotation angle and density phase shift output for plasma control, have been developed for the POINT system. Reliability of both polarimetric and interferometric measurement are obtained in 22 s long pulse H mode discharge and 8 s NBI H mode discharge, indicating the POINT system works for any heating scheme on EAST so far. The electron line-integrated density resolution of POINT is less than 1 × 1016 m-2 (< 1°), and the Faraday rotation angle rms phase noise is < 0.1°. With the high temporal (~ 1 μsec) and phase resolution (< 0.1°), perturbations associated with the sawtooth cycle and MHD activity have been observed. The current profile, density profile and safety factor (q) profile are reconstructed by using EFIT code from the external magnetic and the validation POINT data. Realtime EFIT with Faraday angle and density phase shift constraints will be implemented in the plasma control system in the future.

  10. Comparison of two data acquisition and processing systems of Moller polarimeter in Hall A of Jefferson Lab

    DOE PAGES

    Vereshchaka, Vadym V.; Glamazdin, Oleksandr V.; Pomatsalyuk, Roman I.

    2014-07-01

    Two data acquisition and processing systems are used simultaneously to measure electron beam polarization by Moller polarimeter in Hall A of Jefferson Lab (Newport News, VA, USA). The old system (since 1997) is fully functional, but is not repairable in case of malfunction (system modules arenot manufactured anymore). The new system (since 2010) based on flash-ADC is more accurate, but currently requires more detailed adjustment and further improvement. Description and specifications of two data acquisition and processing systems have been given. The results of polarization measurements during experiments conducted in Hall A from 2010 to 2012 are compared.

  11. A DSP-based readout and online processing system for a new focal-plane polarimeter at AGOR

    NASA Astrophysics Data System (ADS)

    Hagemann, M.; Bassini, R.; van den Berg, A. M.; Ellinghaus, F.; Frekers, D.; Hannen, V. M.; Häupke, T.; Heyse, J.; Jacobs, E.; Kirsch, M.; Krüsemann, B.; Rakers, S.; Sohlbach, H.; Wörtche, H. J.

    1999-11-01

    A Focal-Plane Polarimeter (FPP) for the large acceptance Big-Bite Spectrometer (BBS) at AGOR using a novel readout architecture has been commissioned at the KVI Groningen. The instrument is optimized for medium-energy polarized proton scattering near or at 0°. For the handling of the high counting rates at extreme forward angles and for the suppression of small-angle scattering in the graphite analyzer, a high-performance data processing DSP system connecting to the LeCroy FERA and PCOS ECL bus architecture has been made operational and tested successfully. Details of the system and the functions of the various electronic components are described.

  12. Use of the Far Infrared Tangential Interferometer/Polarimeter diagnostic for the study of rf driven plasma waves on NSTX.

    PubMed

    Kim, J; Lee, K C; Kaita, R; Phillips, C K; Domier, C W; Valeo, E; Luhmann, N C; Bonoli, P T; Park, H

    2010-10-01

    A rf detection system for waves in the 30 MHz range has been constructed for the Far Infrared Tangential Interferometer/Polarimeter on National Spherical Torus Experiment (NSTX). It is aimed at monitoring high frequency density fluctuations driven by 30 MHz high harmonic fast wave fields. The levels of density fluctuations at various radial chords and antenna phase angles can be estimated using the electric field calculated by TORIC code and linearized continuity equation for the electron density. In this paper, the experimental arrangement for the detection of rf signal and preliminary results of simulation will be discussed.

  13. Correlation lifetimes of quiet and magnetic granulation from the SOUP instrument on Spacelab 2. [Solar Optical Universal Polarimeter

    NASA Technical Reports Server (NTRS)

    Title, A.; Tarbell, T.; Topka, K.; Acton, L.; Duncan, D.

    1988-01-01

    The time sequences of diffraction limited granulation images obtained by the Solar Optical Universal Polarimeter on Spacelab 2 are presented. The uncorrection autocorrelation limetime in magnetic regions is dominated by the 5-min oscillation. The removal of this oscillation causes the autocorrelation lifetime to increase by more than a factor of 2. The results suggest that a significant fraction of granule lifetimes are terminated by nearby explosions. Horizontal displacements and transverse velocities in the intensity field are measured. Lower limits to the lifetime in the quiet and magnetic sun are set at 440 s and 950 s, respectively.

  14. Comparison of two data acquisition and processing systems of Moller polarimeter in Hall A of Jefferson Lab

    SciTech Connect

    Vereshchaka, Vadym V.; Glamazdin, Oleksandr V.; Pomatsalyuk, Roman I.

    2014-07-01

    Two data acquisition and processing systems are used simultaneously to measure electron beam polarization by Moller polarimeter in Hall A of Jefferson Lab (Newport News, VA, USA). The old system (since 1997) is fully functional, but is not repairable in case of malfunction (system modules arenot manufactured anymore). The new system (since 2010) based on flash-ADC is more accurate, but currently requires more detailed adjustment and further improvement. Description and specifications of two data acquisition and processing systems have been given. The results of polarization measurements during experiments conducted in Hall A from 2010 to 2012 are compared.

  15. Optical, mechanical and electronic design and integration of POMM, a polarimeter for the Observatoire du mont Mégantic

    NASA Astrophysics Data System (ADS)

    Leclerc, Melanie R.; Côté, Patrice; Duchesne, François; Bastien, Pierre; Hernandez, Olivier; Colonna d'Istria, Pierre; Demers, Mathieu; Girard, Marc; Savard, Maxime; Lemieux, Dany; Thibault, Simon; Brousseau, Denis

    2014-08-01

    A polarimeter, to observe exoplanets in the visible and infrared, was built for the "Observatoire du Mont Mégantic" (OMM) to replace an existing instrument and reach 10-6 precision, a factor 100 improvement. The optical and mechanical designs are presented, with techniques used to precisely align the optical components and rotation axes to achieve the targeted precision. A photo-elastic modulator (PEM) and a lock-in amplifier are used to measure the polarization. The typical signal is a high DC superimposed to a very faint sinusoidal oscillation. Custom electronics was developed to measure the AC and DC amplitudes, and characterization results are presented.

  16. A Stokes drift approximation based on the Phillips spectrum

    NASA Astrophysics Data System (ADS)

    Breivik, Øyvind; Bidlot, Jean-Raymond; Janssen, Peter A. E. M.

    2016-04-01

    A new approximation to the Stokes drift velocity profile based on the exact solution for the Phillips spectrum is explored. The profile is compared with the monochromatic profile and the recently proposed exponential integral profile. ERA-Interim spectra and spectra from a wave buoy in the central North Sea are used to investigate the behavior of the profile. It is found that the new profile has a much stronger gradient near the surface and lower normalized deviation from the profile computed from the spectra. Based on estimates from two open-ocean locations, an average value has been estimated for a key parameter of the profile. Given this parameter, the profile can be computed from the same two parameters as the monochromatic profile, namely the transport and the surface Stokes drift velocity.

  17. An elastic two-sphere swimmer in Stokes flow

    NASA Astrophysics Data System (ADS)

    Nasouri, Babak; Elfring, Gwynn

    2016-11-01

    Swimming at low Reynolds number in Newtonian fluids is only possible through non-reciprocal body deformations due to the kinematic reversibility of the Stokes equations. We consider here a model swimmer consisting of two linked spheres, wherein one sphere is rigid and the other an incompressible neo-Hookean solid. The two spheres are connected by a rod which changes its length periodically. We show that the deformations of the body are non-reciprocal despite the reversible actuation and hence, the elastic two-sphere swimmer propels forward. Our results indicate that even weak elastic deformations of a body can qualitatively alter swimming dynamics and should not be neglected in analyzing swimming in Stokes flows.

  18. Stokes phenomena in discrete Painlevé I

    PubMed Central

    Joshi, N.; Lustri, C. J.

    2015-01-01

    In this study, we consider the asymptotic behaviour of the first discrete Painlevé equation in the limit as the independent variable becomes large. Using an asymptotic series expansion, we identify two types of solutions which are pole-free within some sector of the complex plane containing the positive real axis. Using exponential asymptotic techniques, we determine Stokes phenomena effects present within these solutions, and hence the regions in which the asymptotic series expression is valid. From a careful analysis of the switching behaviour across Stokes lines, we find that the first type of solution is uniquely defined, while the second type contains two free parameters, and that the region of validity may be extended for appropriate choice of these parameters. PMID:27547094

  19. Polarization ellipse and Stokes parameters in geometric algebra.

    PubMed

    Santos, Adler G; Sugon, Quirino M; McNamara, Daniel J

    2012-01-01

    In this paper, we use geometric algebra to describe the polarization ellipse and Stokes parameters. We show that a solution to Maxwell's equation is a product of a complex basis vector in Jackson and a linear combination of plane wave functions. We convert both the amplitudes and the wave function arguments from complex scalars to complex vectors. This conversion allows us to separate the electric field vector and the imaginary magnetic field vector, because exponentials of imaginary scalars convert vectors to imaginary vectors and vice versa, while exponentials of imaginary vectors only rotate the vector or imaginary vector they are multiplied to. We convert this expression for polarized light into two other representations: the Cartesian representation and the rotated ellipse representation. We compute the conversion relations among the representation parameters and their corresponding Stokes parameters. And finally, we propose a set of geometric relations between the electric and magnetic fields that satisfy an equation similar to the Poincaré sphere equation.

  20. Benzothiadiazole oligoene fatty acids: fluorescent dyes with large Stokes shifts

    PubMed Central

    Patalag, Lukas J

    2016-01-01

    Herein, we report on the synthesis and characterization of novel fluorescent fatty acids with large Stokes shifts. Three examples consisting of the same number of carbon atoms and thus of similar chain length are presented differing in their degree of unsaturation. As major fluorogenic contributor at the terminus benzo[c][1,2,5]thiadiazole was used. Respective syntheses based on Wittig reactions followed by iodine-mediated isomerization are presented. The absorption properties are modulated by the number of conjugated C=C double bonds of the oligoene chain ranging from one to three. Large Stokes shifts of about 4900–5700 cm−1 and fluorescence quantum yields of up to 0.44 were observed. PMID:28144344