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Sample records for hydrogen jet polarimeter

  1. 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].

  2. 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.

  3. 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.

  4. ATOMIC BEAM STUDIES IN THE RHIC H-JET POLARIMETER.

    SciTech Connect

    MAKDISI,Y.; ZELENSKI,A.; GRAHAM,D.; KOKHANOVSKI,S.; MAHLER,G.; NASS,A.; RITTER,J.; ZUBETS,V.; ET AL.

    2005-01-28

    The results of atomic beam production studies are presented. Improved cooling of the atoms before jet formation in the dissociator cold nozzle apparently reduces the atomic beam velocity spread and improves beam focusing conditions. A carefully designed sextupole separating (and focusing) magnet system takes advantage of the high brightness source. As a result a record beam intensity of a 12.4 {center_dot} 10{sup 16} atoms/s was obtained within 10 mm acceptance at the collision point. The results of the polarization dilution factor measurements (by the hydrogen molecules at the collision point) are also presented.

  5. 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.

  6. 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.

  7. 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.

  8. Evaluation of the Faraday angle by numerical methods and comparison with the Tore Supra and JET polarimeter electronics.

    PubMed

    Brault, C; Gil, C; Boboc, A; Spuig, P

    2011-04-01

    On the Tore Supra tokamak, a far infrared polarimeter diagnostic has been routinely used for diagnosing the current density by measuring the Faraday rotation angle. A high precision of measurement is needed to correctly reconstruct the current profile. To reach this precision, electronics used to compute the phase and the amplitude of the detected signals must have a good resilience to the noise in the measurement. In this article, the analogue card's response to the noise coming from the detectors and their impact on the Faraday angle measurements are analyzed, and we present numerical methods to calculate the phase and the amplitude. These validations have been done using real signals acquired by Tore Supra and JET experiments. These methods have been developed to be used in real-time in the future numerical cards that will replace the Tore Supra present analogue ones. PMID:21678660

  9. Status of the Michigan ultra-cold spin-polarized hydrogen jet target

    NASA Astrophysics Data System (ADS)

    Kageya, T.; Anferov, V. A.; Arnold, J. D.; Blinov, B. B.; Celik, M.; Centurion, M.; Gladycheva, S. E.; Krisch, A. D.; Lin, A. M. T.; Luppov, V. G.; Raymond, R. S.; Sourkont, K. V.; Wu, Y.-W.; Youssof, S. S.; Chuiko, B. V.; Grishin, V. N.; Khodyrev, V. Yu.; Mochalov, V. V.; Prudkoglyad, A. F.; Semenov, P. A.; Yakutin, A. E.; Bychkov, M. A.; Fimushkin, V. V.

    1998-04-01

    We are developing a high density ultra-cold jet target of proton-spin-polarized hydrogen atoms in order to study spin effects in high energy p-p collisions. The target uses a 12 T magnetic field, an ultra-cold separation cell whose 0.3 K surface is coated with superfluid ^4He, and a radio-frequency (rf) transition unit. The 12 T field and 0.3 K temperature produce an electron-spin-polarized atomic hydrogen beam; the rf unit then transforms it into a proton-spin-polarized beam. Recent progress on the dilution refrigerator and atomic hydrogen beam line will be discussed. The rf transition unit and maser polarimeter will be discussed by another speaker.

  10. Recent developments of the JET far-infrared interferometer-polarimeter diagnostic

    SciTech Connect

    Boboc, A.; Murari, A.; Collaboration: JET-EFDA Contributors

    2010-10-15

    The far-infrared diagnostic provides essential internal measurements of the plasma density and magnetic field topology (q-profile via Faraday rotation angle) in real-time. The diagnostic capabilities have recently been extended in a number of key areas. Fast interferometer data, with 10 {mu}s time resolution, and a new MATLAB code have allowed improved analysis of the evolution of density profiles during fast events such as vertical plasma displacements, edge localized mode, pellet fuelling, and disruptions. Using the polarimeter measurements in real-time, a new calibration procedure has been developed based on a propagation code using the Mueller matrix formalism. A further major upgrade of the system is presently underway: adding a second color laser to the vertical channels and implementing a new phase counter based on analog zero crossing and field-programmable gate array boards.

  11. 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.

  12. Optical beam profile monitor and residual gas fluorescence at the relativistic heavy ion collider polarized hydrogen jet.

    PubMed

    Tsang, T; Bellavia, S; Connolly, R; Gassner, D; Makdisi, Y; Russo, T; Thieberger, P; Trbojevic, D; Zelenski, A

    2008-10-01

    A gas fluorescence beam profile monitor has been implemented at the relativistic heavy ion collider (RHIC) using the polarized atomic hydrogen gas jet, which is part of the polarized proton polarimeter. RHIC proton beam profiles in the vertical plane of the accelerator are obtained as well as measurements of the width of the gas jet in the beam direction. For gold ion beams, the fluorescence cross section is sufficiently large so that profiles can be obtained from the residual gas alone, albeit with long light integration times. We estimate the fluorescence cross sections that were not known in this ultrarelativistic regime and calculate the beam emittance to provide an independent measurement of the RHIC beam. This optical beam diagnostic technique, utilizing the beam induced fluorescence from injected or residual gas, offers a noninvasive particle beam characterization and provides visual observation of proton and heavy ion beams. PMID:19044742

  13. Refrigerated hydrogen gas jet for the Fermilab antiproton accumulator

    SciTech Connect

    Allspach, D.H.; Kendziora, C.L.; Marinelli, M.

    1995-07-01

    A hydrogen gas jet has been built for use at Fermilab for the study of charmonium spectroscopy in proton-antiproton annihilations. The hydrogen gas jet is part of an upgrade to a previous experiment which ran in the Fermilab 1990-1991 fixed target program utilizing a jet cooled to 80 K with liquid nitrogen. The jet delivers a defined stream of hydrogen gas which travels through a series of vacuum chambers and then intersects the circulating antiproton beam. The goal of the upgrade is to provide a hydrogen gas stream at least twice as dense as used for the earlier experiment to increase the interaction rate and allow an improved study of rare processes. This is achieved by cooling the stream to below 30 K using a Gifford-McMahon refrigerator. The jet apparatus is designed to allow motion in the plane perpendicular to the gas stream as well as angular positioning at the jet nozzle to provide a means of optimizing the interaction rate. Two skimmers located in the vacuum chambers are used to define the gas stream dimensions. The jet target vacuum chambers require constant pumping with turbomolecular pumps. The vacuum space around the jet is designed to have a large system pumping speed so that the chamber pressure can be maintained below an absolute pressure of 1 Pa. The jet will operate in the next fixed target run at Fermilab. Details of the design and test results are discussed.

  14. 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.

  15. LEP and CEBAF Polarimeters

    SciTech Connect

    Rossmanith, Robert; Burkert, Volker; Placidi, Massimo

    1988-09-01

    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 Moller polarimeter (for currents below 1 micro-amp).

  16. Shocked Molecular Hydrogen in Herbig-Haro Objects and Jets

    NASA Technical Reports Server (NTRS)

    Schultz, A.S.B.; Rank, D.; Temi, P.; Harker, D.

    1995-01-01

    We present near-IR array images of the shocked molecular hydrogen in Herbig-Haro objects and jets from YSOs. These observations, in combination with optical and EEL observations of atomic emission, serve as probes of the shock conditions within the objects.

  17. Hydrogen enrichment for low-emission jet combustion

    NASA Technical Reports Server (NTRS)

    Clayton, R. M.

    1978-01-01

    Simultaneous gaseous pollutant emission indexes (g pollutant/kg fuel) for a research combustor with inlet air at 120,900 N/sq m (11.9 atm) pressure and 727 K (849 F) temperature are as low as 1.0 for NOx and CO and 0.5 for unburned HC. Emissions data are presented for hydrogen/jet fuel (JP-5) mixes and for jet fuel only for premixed equivalence ratios from lean blowout to 0.65. Minimized emissions were achieved at an equivalence ratio of 0.38 using 10-12 mass percent hydrogen in the total fuel to depress the lean blowout limit. They were not achievable with jet fuel alone because of the onset of lean blowout at an equivalence ratio too high to reduce the NOx emission sufficiently.

  18. Michigan ultra-cold polarized atomic hydrogen jet target

    NASA Astrophysics Data System (ADS)

    Blinov, B. B.; Gladycheva, S. E.; Kageya, T.; Kantsyrev, D. Yu.; Krisch, A. D.; Luppov, V. G.; Morozov, V. S.; Murray, J. R.; Raymond, R. S.; Borisov, N. S.; Fimushkin, V. V.; Grishin, V. N.; Mysnik, A. I.; Kleppner, D.

    2001-06-01

    To study spin effects in high energy collisions, we are developing an ultra-cold high-density jet target of proton-spin-polarized hydrogen atoms. The target uses a 12 Tesla magnetic field and a 0.3 K separation cell coated with superfluid helium-4 to produce a slow monochromatic electron-spin-polarized atomic hydrogen beam, which is then focused by a superconducting sextupole into the interaction region. In recent tests, we studied a polarized beam of hydrogen atoms focused by the superconducting sextupole into a compression tube detector, which measured the polarized atoms' intensity. The Jet produced, at the detector, a spin-polarized atomic hydrogen beam with a measured intensity of about 2.8.1015 H s-1 and a FWHM area of less than 0.13 cm2. This intensity corresponds to a free jet density of about 1.1012 H cm-3 with a proton polarization of about 50%. When the transition RF unit is installed, we expect a proton polarization higher than 90%. .

  19. Molecular hydrogen jets from the Orion nebula

    NASA Astrophysics Data System (ADS)

    Taylor, K. N. R.; Storey, J. W. V.; Sandell, G.; Williams, P. M.; Zealey, W. J.

    1984-09-01

    In an attempt to understand the relationship of the recently discovered complex of Herbig Haro objects in Orion to the IR sources in this region, the authors have carried out a survey of the molecular hydrogen S(1) line distribution. These observations have led to the discovery of a previously unsuspected structure of finger-like filaments of H2 emission extending radially outwards from a common centre at IRC9.

  20. Ignition and Unburned Hydrogen Escaping from Hydrogen Diffusion Jet Flame Diluted with Nitrogen

    SciTech Connect

    Tran, P.X.; Soong, Yee

    2007-07-01

    Ignition and unburned hydrogen escaping from hydrogen jet diffusion flames diluted with nitrogen up to 70% were experimentally studied. The successful ignition locations were about 2/3 of the flame length above the jet exit for undiluted flames and moved much closer to the exit for diluted flames. For higher levels of dilution or higher flow rates, there existed a region within which a diluted hydrogen diffusion flame can be ignited and burns with a stable liftoff height. This is contrary to previous findings that pure and diluted hydrogen jet diffusion cannot achieve a stable lifted flame configuration. With liftoff, the flame is noisy and short with significant amount of unburned hydrogen escaping into the product gases. If ignition is initiated below this region, the flame propagates upstream quickly and attaches to the burner rim. Results from measurements of unburned hydrogen in the combustion products showed that the amount of unburned hydrogen increased as the nitrogen dilution level was increased. Thus, hydrogen diffusion flame diluted with nitrogen cannot burn completely.

  1. Invited Article: A novel calibration method for the JET real-time far infrared polarimeter and integration of polarimetry-based line-integrated density measurements for machine protection of a fusion plant

    NASA Astrophysics Data System (ADS)

    Boboc, A.; Bieg, B.; Felton, R.; Dalley, S.; Kravtsov, Yu.

    2015-09-01

    In this paper, we present the work in the implementation of a new calibration for the JET real-time polarimeter based on the complex amplitude ratio technique and a new self-validation mechanism of data. This allowed easy integration of the polarimetry measurements into the JET plasma density control (gas feedback control) and as well as machine protection systems (neutral beam injection heating safety interlocks). The new addition was used successfully during 2014 JET Campaign and is envisaged that will operate routinely from 2015 campaign onwards in any plasma condition (including ITER relevant scenarios). This mode of operation elevated the importance of the polarimetry as a diagnostic tool in the view of future fusion experiments.

  2. Invited Article: A novel calibration method for the JET real-time far infrared polarimeter and integration of polarimetry-based line-integrated density measurements for machine protection of a fusion plant

    SciTech Connect

    Boboc, A. Felton, R.; Dalley, S.; Bieg, B.; Kravtsov, Yu.

    2015-09-15

    In this paper, we present the work in the implementation of a new calibration for the JET real-time polarimeter based on the complex amplitude ratio technique and a new self-validation mechanism of data. This allowed easy integration of the polarimetry measurements into the JET plasma density control (gas feedback control) and as well as machine protection systems (neutral beam injection heating safety interlocks). The new addition was used successfully during 2014 JET Campaign and is envisaged that will operate routinely from 2015 campaign onwards in any plasma condition (including ITER relevant scenarios). This mode of operation elevated the importance of the polarimetry as a diagnostic tool in the view of future fusion experiments.

  3. Numerical Simulation of Hydrogen Air Supersonic Coaxial Jet

    NASA Astrophysics Data System (ADS)

    Dharavath, Malsur; Manna, Pulinbehari; Chakraborty, Debasis

    2016-06-01

    In the present study, the turbulent structure of coaxial supersonic H2-air jet is explored numerically by solving three dimensional RANS equations along with two equation k-ɛ turbulence model. Grid independence of the solution is demonstrated by estimating the error distribution using Grid Convergence Index. Distributions of flow parameters in different planes are analyzed to explain the mixing and combustion characteristics of high speed coaxial jets. The flow field is seen mostly diffusive in nature and hydrogen diffusion is confined to core region of the jet. Both single step laminar finite rate chemistry and turbulent reacting calculation employing EDM combustion model are performed to find the effect of turbulence-chemistry interaction in the flow field. Laminar reaction predicts higher H2 mol fraction compared to turbulent reaction because of lower reaction rate caused by turbulence chemistry interaction. Profiles of major species and temperature match well with experimental data at different axial locations; although, the computed profiles show a narrower shape in the far field region. These results demonstrate that standard two equation class turbulence model with single step kinetics based turbulence chemistry interaction can describe H2-air reaction adequately in high speed flows.

  4. Shock-wave proton acceleration from a hydrogen gas jet

    NASA Astrophysics Data System (ADS)

    Cook, Nathan; Pogorelsky, Igor; Polyanskiy, Mikhail; Babzien, Marcus; Tresca, Olivier; Maharjan, Chakra; Shkolnikov, Peter; Yakimenko, Vitaly

    2013-04-01

    Typical laser acceleration experiments probe the interaction of intense linearly-polarized solid state laser pulses with dense metal targets. This interaction generates strong electric fields via Transverse Normal Sheath Acceleration and can accelerate protons to high peak energies but with a large thermal spectrum. Recently, the advancement of high pressure amplified CO2 laser technology has allowed for the creation of intense (10^16 Wcm^2) pulses at λ˜10 μm. These pulses may interact with reproducible, high rep. rate gas jet targets and still produce plasmas of critical density (nc˜10^19 cm-3), leading to the transference of laser energy via radiation pressure. This acceleration mode has the advantage of producing narrow energy spectra while scaling well with pulse intensity. We observe the interaction of an intense CO2 laser pulse with an overdense hydrogen gas jet. Using two pulse optical probing in conjunction with interferometry, we are able to obtain density profiles of the plasma. Proton energy spectra are obtained using a magnetic spectrometer and scintillating screen.

  5. 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.

  6. 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.

  7. Direct Numerical Simulations of Turbulent Autoigniting Hydrogen Jets

    NASA Astrophysics Data System (ADS)

    Asaithambi, Rajapandiyan

    Autoignition is an important phenomenon and a tool in the design of combustion engines. To study autoignition in a canonical form a direct numerical simulation of a turbulent autoigniting hydrogen jet in vitiated coflow conditions at a jet Reynolds number of 10,000 is performed. A detailed chemical mechanism for hydrogen-air combustion and non-unity Lewis numbers for species transport is used. Realistic inlet conditions are prescribed by obtaining the velocity eld from a fully developed turbulent pipe flow simulation. To perform this simulation a scalable modular density based method for direct numerical simulation (DNS) and large eddy simulation (LES) of compressible reacting flows is developed. The algorithm performs explicit time advancement of transport variables on structured grids. An iterative semi-implicit time advancement is developed for the chemical source terms to alleviate the chemical stiffness of detailed mechanisms. The algorithm is also extended from a Cartesian grid to a cylindrical coordinate system which introduces a singularity at the pole r = 0 where terms with a factor 1/r can be ill-defined. There are several approaches to eliminate this pole singularity and finite volume methods can bypass this issue by not storing or computing data at the pole. All methods however face a very restrictive time step when using a explicit time advancement scheme in the azimuthal direction (theta) where the cell sizes are of the order DelrDeltheta. We use a conservative finite volume based approach to remove the severe time step restriction imposed by the CFL condition by merging cells in the azimuthal direction. In addition, fluxes in the radial direction are computed with an implicit scheme to allow cells to be clustered along the jet's shear layer. This method is validated and used to perform the large scale turbulent reacting simulation. The resulting flame structure is found to be similar to a turbulent diusion flame but stabilized by autoignition at the

  8. A study of the efficiency of hydrogen liquefaction. [jet aircraft applications

    NASA Technical Reports Server (NTRS)

    Baker, C. R.; Shaner, R. L.

    1976-01-01

    The search for an environmentally acceptable fuel to eventually replace petroleum-based fuels for long-range jet aircraft has singled out liquid hydrogen as an outstanding candidate. Hydrogen liquefaction is discussed, along with the effect of several operating parameters on process efficiency. A feasible large-scale commercial hydrogen liquefaction facility based on the results of the efficiency study is described. Potential future improvements in hydrogen liquefaction are noted.

  9. Status on the Michigan-MIT ultra-cold polarized hydrogen jet target

    NASA Astrophysics Data System (ADS)

    Luppov, V. G.; Blinov, B. B.; Bywater, J. A.; Chin, S.; Churakov, V. V.; Court, G. R.; Kaufman, W. A.; Kleppner, D.; Krisch, A. D.; Melnik, Yu. M.; Muldavin, J. B.; Nurushev, T. S.; Price, J. S.; Prudkoglyad, A. F.; Raymond, R. S.; Shutov, V. B.; Stewart, J. A.

    1995-07-01

    Progress on the Mark-II ultra-cold polarized atomic hydrogen gas Jet target for the experiments NEPTUN-A and NEPTUN at UNK is presented. We describe the performance and the present status of different components of the jet.

  10. The Penn Polarimeters

    NASA Astrophysics Data System (ADS)

    Koch, Robert H.; Wolf, George W.; Hull, Anthony B.; Elias, Nicholas M., II; Holenstein, Bruce D.; Mitchell, Richard J.

    2012-03-01

    This report describes the inception, development and extensive use over 30 years of elliptical polarimeters at the University of Pennsylvania. The initial Mark I polarimeter design utilized oriented retarder plates and a calcite Foster-Clarke prism as the analyzer. The Mark I polarimeter was used on the Kitt Peak 0.9 m in 1969-70 to accomplish a survey of approximately 70 objects before the device was relocated to the 0.72 m reflector at the Flower and Cook Observatory. Successive generations of automation and improvements included the early-80's optical redesign to utilize a photoelastic modulated wave plate and an Ithaco lock-in amplifier - the photoelastic modulating polarimeter. The final design in 2000 concluded with a fully remote operable device. The legacy of the polarimetric programs includes studies of close binaries, pulsating hot stars, and luminous late-type variables.

  11. Analysis of Material Sample Heated by Impinging Hot Hydrogen Jet in a Non-Nuclear Tester

    NASA Technical Reports Server (NTRS)

    Wang, Ten-See; Foote, John; Litchford, Ron

    2006-01-01

    A computational conjugate heat transfer methodology was developed and anchored with data obtained from a hot-hydrogen jet heated, non-nuclear materials tester, as a first step towards developing an efficient and accurate multiphysics, thermo-fluid computational methodology to predict environments for hypothetical solid-core, nuclear thermal engine thrust chamber. The computational methodology is based on a multidimensional, finite-volume, turbulent, chemically reacting, thermally radiating, unstructured-grid, and pressure-based formulation. The multiphysics invoked in this study include hydrogen dissociation kinetics and thermodynamics, turbulent flow, convective and thermal radiative, and conjugate heat transfers. Predicted hot hydrogen jet and material surface temperatures were compared with those of measurement. Predicted solid temperatures were compared with those obtained with a standard heat transfer code. The interrogation of physics revealed that reactions of hydrogen dissociation and recombination are highly correlated with local temperature and are necessary for accurate prediction of the hot-hydrogen jet temperature.

  12. Studies and proposed changes to the RHIC p-Carbon polarimeters for the upcoming RUN-11

    SciTech Connect

    Makdisi, Y.; Alekseev, I.; Aschenauer, E.; Atoian, G.; Bazilevsky, A.; Gill, R.; Huang, H.; Morozov, B.; Svirida, D.; Yip, K.; Zelenski, A.

    2010-09-27

    The RHIC polarized proton complex utilizes polarimeters in each of the Blue and Yellow beams that measure the beam polarization through the p-Carbon elastic scattering process in the Coulomb Nuclear Interference kinematic region. This along with a Polarized Hydrogen Jet Target that utilizes the proton-proton elastic scattering process to first measure the analyzing power of the reaction and using the reverse process to measure the beam polarization. The latter is used to calibrate the p-Carbon polarimeters at the desired beam energy. In Run 9 RHIC ran with beams at center-of-mass energies of 200 and 500 GeV respectively. The higher beam intensities as well as the fact that the 250 GeV beam size is much smaller than that at 100 GeV resulted in significantly higher rates seen by the polarimeters and led to observed instability. In this paper, we will discuss the problems encountered and the tests that were carried out using the AGS as a proxy in an attempt to solve the problems and the path forward we took towards the upcoming polarized proton Run11.

  13. 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.

  14. Hydrogen abstraction in the neutral molecular cluster of benzophenone and hydrogen donors formed in a supersonic free jet expansion

    SciTech Connect

    Matsushita, Yoshihisa; Kajii, Yoshizumi; Obi, Kinichi

    1992-08-06

    This paper discusses how benzophenone undergoes photoreduction to form benzophenone ketyl radical by an intracellular reaction in the benzophenone 1,4-cyclohexadiene mixed expansion in a supersonic free jet expansion. No ketyl radical fluorescence is observed when triethylamine, 2-propanol, or ethanol is the hydrogen donor; thus the normal molecular cluster activity depends on the nature of the hydrogen donor. 36 refs., 5 figs.

  15. 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.

  16. A new approach for bio-jet fuel generation from palm oil and limonene in the absence of hydrogen.

    PubMed

    Zhang, Jingjing; Zhao, Chen

    2015-12-18

    The traditional methodology includes a carbon-chain shortening strategy to produce bio-jet fuel from lipids via a two-stage process with hydrogen. Here, we propose a new solution using a carbon-chain filling strategy to convert C10 terpene and lipids to jet fuel ranged hydrocarbons with aromatic hydrocarbon ingredients in the absence of hydrogen. PMID:26459451

  17. Large Eddy Simulation and PIV Visualization of a Vertical Hydrogen Jet

    NASA Astrophysics Data System (ADS)

    Pedro, G.; Peneau, F.; Wu, T. C.; Oshkai, P.; Djilali, N.

    2006-11-01

    Increasing concerns about green house gas emissions and deteriorating local air quality will necessitate substantial emission reductions, particularly from road vehicles. Canada has made important contributions in paving the way for the use of hydrogen in the transportation sector, which could lead to a substantial reduction of urban pollution and CO2 emissions. However production and storage issues, as well as the absence of specific standards for hydrogen are regarded as obstacles to the introduction of hydrogen in the energy market. A hydrogen jet exiting into quiescent air in both the supersonic and subsonic regimes is simulated using large eddy simulation with a Smagorinski subgrid model. The subsonic results are compared with experimental results obtained by Panchapakesan et al. and So et al. Using a high speed PIV system, a subsonic air-in-air jet is studied and the time averaged flow-field is compared to the one obtained in the simulation.

  18. Vehicle-scale investigation of a fluorine jet-pump liquid hydrogen tank pressurization system

    NASA Technical Reports Server (NTRS)

    Cady, E. C.; Kendle, D. W.

    1972-01-01

    A comprehensive analytical and experimental program was performed to evaluate the performance of a fluorine-hydrogen jet-pump injector for main tank injection (MTI) pressurization of a liquid hydrogen (LH2) tank. The injector performance during pressurization and LH2 expulsion was determined by a series of seven tests of a full-scale injector and MTI pressure control system in a 28.3 cu m (1000 cu ft) flight-weight LH2 tank. Although the injector did not effectively jet-pump LH2 continuously, it showed improved pressurization performance compared to straight-pipe injectors tested under the same conditions in a previous program. The MTI computer code was modified to allow performance prediction for the jet-pump injector.

  19. Modelisations des effets de surface sur les jets horizontaux subsoniques d'hydrogene et de methane

    NASA Astrophysics Data System (ADS)

    Gomez, Luis Fernando

    Le developpement des codes et de normes bases sur une methodologie scientifique requiert la capacite de predire l'etendue inflammable de deversements gazeux d'hydrogene sous differentes conditions. Des etudes anterieures ont deja etabli des modeles bases sur les lois de conservation de la mecanique des fluides basees sur des correlations experimentales qui permettent de predire la decroissance de la concentration et de la vitesse d'un gaz le long de l'axe d'un jet libre vertical. Cette etude s'interesse aux effets de proximite a une surface horizontale parallele sur un jet turbulent. Nous nous interessons a son impact sur l'etendue du champ de la concentration et sur l'enveloppe inflammable en particulier. Cette etude est comparative : l'hydrogene est compare au methane. Ceci permet de degager l'influence des effets de difference de la densite sur le comportement du jet, et de comparer le comportement de l'hydrogene aux correlations experimentales, qui ont ete essentiellement etablies pour le methane. Un modele decrivant l'evolution spatio-temporelle du champ de concentration du gaz dilue est propose, base sur la mecanique des fluides computationnelle. Cette approche permet de varier systematiquement les conditions aux frontieres (proximite du jet a la surface, par exemple) et de connaitre en detail les proprietes de l'ecoulement. Le modele est implemente dans le code de simulations par volumes finis de FLUENT. Les resultats des simulations sont compares avec les lois de similitudes decoulant de la theorie des jets d'ecoulements turbulents libres ainsi qu'avec les resultats experimentaux disponibles. L'effet de la difference des masses molaires des constituantes du jet et des constituantes du milieu de dispersion est egalement etudie dans le contexte du comportement d'echelle de la region developpee du jet.

  20. Effects of Buoyancy in Hydrogen Jet Diffusion Flames

    NASA Technical Reports Server (NTRS)

    Agrawal, A. K.; Al-Ammar, K.; Gollahalli, S. R.; Griffin, D. W.

    1999-01-01

    This project was carried out to understand the effects of heat release and buoyancy on the flame structure of diffusion flames. Experiments were conducted at atmospheric pressure in both normal gravity and microgravity conditions in the NASA LeRC 2.2 s drop tower. Experiments were also conducted in a variable pressure combustion facility in normal gravity to scale buoyancy and thus, to supplement the drop tower experiments. Pure H2 or H2 mixed with He was used as the jet fluid to avoid the complexities associated with soot formation. Fuel jet burning in quiescent air was visualized and quantified by the Rainbow Schlieren Deflectometry (RSD) to obtain scalar profiles (temperature, oxygen concentration) within the flame. Burner tube diameter (d) was varied from 0.3 to 1.19 mm producing jet exit Reynolds numbers ranging from 40 to 1900, and generating flames encompassing laminar and transitional (laminar to turbulent) flow structure. Some experiments were also complemented with the CFD analysis. In a previous paper, we have presented details of the RSD technique, comparison of computed and measured scalar distributions, and effects of buoyancy on laminar and transitional H2 gas-jet diffusion flames. Results obtained from the RSD technique, variable pressure combustion chamber, and theoretical models have been published. Subsequently, we have developed a new drop rig with improved optical and image acquisition. In this set up, the schlieren images are acquired in real time and stored digitally in RAM of an onboard computer. This paper deals with laminar diffusion flames of pure H2 in normal and microgravity.

  1. Buoyancy Effects on Flow Transition in Hydrogen Gas Jet Diffusion Flames

    NASA Technical Reports Server (NTRS)

    Albers, Burt W.; Agrawal, Ajay K.; Griffin, DeVon (Technical Monitor)

    2000-01-01

    Experiments were performed in earth-gravity to determine how buoyancy affected transition from laminar to turbulent flow in hydrogen gas jet diffusion flames. The jet exit Froude number characterizing buoyancy in the flame was varied from 1.65 x 10(exp 5) to 1.14 x 10(exp 8) by varying the operating pressure and/or burner inside diameter. Laminar fuel jet was discharged vertically into ambient air flowing through a combustion chamber. Flame characteristics were observed using rainbow schlieren deflectometry, a line-of-site optical diagnostic technique. Results show that the breakpoint length for a given jet exit Reynolds number increased with increasing Froude number. Data suggest that buoyant transitional flames might become laminar in the absence of gravity. The schlieren technique was shown as effective in quantifying the flame characteristics.

  2. The submillimeter array polarimeter

    NASA Astrophysics Data System (ADS)

    Marrone, Daniel P.; Rao, Ramprasad

    2008-07-01

    We describe the Submillimeter Array (SMA) Polarimeter, a polarization converter and feed multiplexer installed on the SMA. The polarimeter uses narrow-band quarter-wave plates to generate circular polarization sensitivity from the linearly-polarized SMA feeds. The wave plates are mounted in rotation stages under computer control so that the polarization handedness of each antenna is rapidly selectable. Positioning of the wave plates is found to be highly repeatable, better than 0.2 degrees. Although only a single polarization is detected at any time, all four cross correlations of left- and right-circular polarization are efficiently sampled on each baseline through coordinated switching of the antenna polarizations in Walsh function patterns. The initial set of anti-reflection coated quartz and sapphire wave plates allows polarimetry near 345 GHz; these plates have been have been used in observations between 325 and 350 GHz. The frequency-dependent cross-polarization of each antenna, largely due to the variation with frequency of the retardation phase of the single-element wave plates, can be measured precisely through observations of bright point sources. Such measurements indicate that the cross-polarization of each antenna is a few percent or smaller and stable, consistent with the expected frequency dependence and very small alignment errors. The polarimeter is now available for general use as a facility instrument of the SMA.

  3. Supersonic jets of hydrogen and helium for laser wakefield acceleration

    NASA Astrophysics Data System (ADS)

    Svensson, K.; Hansson, M.; Wojda, F.; Senje, L.; Burza, M.; Aurand, B.; Genoud, G.; Persson, A.; Wahlström, C.-G.; Lundh, O.

    2016-05-01

    The properties of laser wakefield accelerated electrons in supersonic gas flows of hydrogen and helium are investigated. At identical backing pressure, we find that electron beams emerging from helium show large variations in their spectral and spatial distributions, whereas electron beams accelerated in hydrogen plasmas show a higher degree of reproducibility. In an experimental investigation of the relation between neutral gas density and backing pressure, it is found that the resulting number density for helium is ˜30 % higher than for hydrogen at the same backing pressure. The observed differences in electron beam properties between the two gases can thus be explained by differences in plasma electron density. This interpretation is verified by repeating the laser wakefield acceleration experiment using similar plasma electron densities for the two gases, which then yielded electron beams with similar properties.

  4. L-H threshold results in hydrogen plasmas in JET-ILW

    NASA Astrophysics Data System (ADS)

    Delabie, E.; Maggi, C.; Solano, E.; Meyer, H.; Lerche, E.; Keeling, D.; JET Contributors Team

    2015-11-01

    The ITPA scaling law for the H-mode power threshold, P(L-H), is strongly weighted to a dataset of carbon wall JET (JET-C) discharges. Identical discharges with the Be/W wall (JET-ILW) in deuterium have shown a 30% reduction of P(L-H) and a minimum as function of density, not observed with the current divertor in JET-C. A strong dependence of P(L-H) on the divertor configuration was found, linked to changes in the divertor recycling pattern. Subsequently, an experiment was conducted in hydrogen to investigate the isotope effect on P(L-H) in JET-ILW. P(L-H) is increased by a factor 2 in the high density branch, as expected. Remarkably, ne,min is shifted to higher density. Comparison between the hydrogen and deuterium discharges show the transition occurs at similar values of stored energy and closely matched edge density and temperature profiles. Work supported, in part, by the US DOE under Contract No. DE-AC05-00OR22725 with UT-Battelle, LLC.

  5. Polarized Atomic Hydrogen Beam Tests in the Michigan Ultra-Cold Jet Target

    NASA Astrophysics Data System (ADS)

    Kageya, T.; Blinov, B. B.; Denbow, J. M.; Kandes, M. C.; Krisch, A. D.; Kulkarni, D. A.; Lehman, M. A.; Luppov, V. G.; Morozov, V. S.; Murray, J. R.; Peters, C. C.; Raymond, R. S.; Ross, M. R.; Yonehara, K.; Borisov, N. S.; Fimushkin, V. V.; Kleppner, D.; Grishin, V. N.; Mysnik, A. L.

    2001-04-01

    To study spin effects in high energy collisions, we are developing an ultra-cold high-density jet target of proton-spin-polarized hydrogen atoms (Michigan Jet Target). The target uses a 12 Tesla magnetic field and a 0.3 K separation cell coated with superfluid helium-4 to produce a slow monochromatic electron-spin-polarized atomic hydrogen beam; an rf transition unit then converts this into a proton-spin-polarized beam, which is focused by a superconducting sextupole into the interaction region. The Jet produced, at the detector, a spin-polarized atomic hydrogen beam with a measured intensity of about 1.7 10^15 H s-1 and a FWHM area of less than 0.13 cm^2. This intensity corresponds to a free jet density of about 1.3 10^12 H cm-3 with a proton polarization of about 50%. When the transition RF unit is installed, we expect a proton polarization higher than 90%.

  6. Global NOx Measurements in Turbulent Nitrogen-Diluted Hydrogen Jet Flames

    SciTech Connect

    Weiland, N.T.; Strakey, P.A.

    2007-03-01

    Turbulent hydrogen diffusion flames diluted with nitrogen are currently being studied to assess their ability to achieve the DOE Turbine Program’s aggressive emissions goal of 2 ppm NOx in a hydrogen-fueled IGCC gas turbine combustor. Since the unstrained adiabatic flame temperatures of these diluted flames are not low enough to eliminate thermal NOx formation the focus of the current work is to study how the effects of flame residence time and global flame strain can be used to help achieve the stated NOx emissions goal. Dry NOx measurements are presented as a function of jet diameter nitrogen dilution and jet velocity for a turbulent hydrogen/nitrogen jet issuing from a thin-lipped tube in an atmospheric pressure combustor. The NOx emission indices from these experiments are normalized by the flame residence time to ascertain the effects of global flame strain and fuel Lewis Number on the NOx emissions. In addition dilute hydrogen diffusion flame experiments were performed in a high-pressure combustor at 2 4 and 8 atm. The NOx emission data from these experiments are discussed as well as the results from a Computational Fluid Dynamics modeling effort currently underway to help explain the experimental data.

  7. LWIR polarimeter calibration

    NASA Astrophysics Data System (ADS)

    Blumer, Robert V.; Miller, Miranda A.; Howe, James D.; Stevens, Mark A.

    2002-01-01

    Performance reported efforts to calibrate a MWIR imaging polarimeter met with moderate success. Recent efforts to calibrate a LWIR sensor using a different technique have been much more fruitful. For our sensor, which is based on a rotating retarder, we have improved system calibration substantially be including nonuniformity correction at all measurement positions of the retarder in our polarization data analysis. This technique can account for effects such as spurious optical reflections within a camera system that had been masquerading as false polarization in our previous data analysis methodology. Our techniques will be described and our calibration results will be quantified. Data from field-testing will be presented.

  8. 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.

  9. Production of high brightness H- beam by charge exchange of hydrogen atom beam in sodium jet

    SciTech Connect

    Davydenko, V.; Zelenski, A.; Ivanov, A.; Kolmogorov, A.

    2010-11-16

    Production of H{sup -} beam for accelerators applications by charge exchange of high brightness hydrogen neutral beam in a sodium jet cell is experimentally studied in joint BNL-BINP experiment. In the experiment, a hydrogen-neutral beam with 3-6 keV energy, equivalent current up to 5 A and 200 microsecond pulse duration is used. The atomic beam is produced by charge exchange of a proton beam in a pulsed hydrogen target. Formation of the proton beam is performed in an ion source by four-electrode multiaperture ion-optical system. To achieve small beam emittance, the apertures in the ion-optical system have small enough size, and the extraction of ions is carried out from the surface of plasma emitter with a low transverse ion temperature of {approx}0.2 eV formed as a result of plasma jet expansion from the arc plasma generator. Developed for the BNL optically pumped polarized ion source, the sodium jet target with recirculation and aperture diameter of 2 cm is used in the experiment. At the first stage of the experiment H{sup -} beam with 36 mA current, 5 keV energy and {approx}0.15 cm {center_dot} mrad normalized emittance was obtained. To increase H{sup -} beam current ballistically focused hydrogen neutral beam will be applied. The effects of H{sup -} beam space-charge and sodium-jet stability will be studied to determine the basic limitations of this approach.

  10. Polarized Atomic Hydrogen Beam Tests in the Mark-II Ultra-Cold Jet Target.

    NASA Astrophysics Data System (ADS)

    Luppov, V. G.; Blinov, B. B.; Gladycheva, S. E.; Kageya, T.; Kantsyrev, D. Yu.; Krisch, A. D.; Murray, J. R.; Neumann, J. J.; Raymond, R. S.; Borisov, N. S.; Kleppner, D.; Davidenko, A. M.; Grishin, V. N.

    2000-04-01

    To study spin effects in high energy collisions, we are developing an ultra-cold high-density jet target of proton-spin-polarized hydrogen atoms (Mark-II). The target uses a 12 Tesla magnetic field and a 0.3 K separation cell coated with superfluid helium-4 to produce a slow monochromatic electron-spin-polarized atomic hydrogen beam; an rf transition unit then converts this into a proton-spin-polarized beam, which is focused by a superconducting sextupole into the interaction region. Recently, the Jet produced a measured electron-spin-polarized atomic hydrogen beam of about 10^15 H s-1 into a 0.3 cm^2 area at the detector. This intensity corresponds to the free jet density of about 10^11 H cm-3 with a proton polarization of about 50%. So far, the intensity is limited by the high insulation vacuum pressure due to the evaporation of the separation cell's helium film. The beam's angular and radial distributions were measured. A test of a new superfluid-^4He-coated parabolic mirror, attached to the separation cell, appeared to increase the beam intensity by a factor of about 3, as expected.

  11. Structures and the Hydrogen Bonding Abilities of Estrogens Studied by Supersonic Jet/laser Spectroscopy

    NASA Astrophysics Data System (ADS)

    Morishima, Fumiya; Inokuchi, Yoshiya; Ebata, Takayuki

    2013-06-01

    Estrone, estradiol, estriol are known as endogenous estrogen which have the same steroidal frame with different substituent, leading to difference of physiological activity upon the formation of hydrogen bond with estrogen receptor. In the present study, structures of estrogens and their hydrated clusters in a supersonic jet have been studied by various laser spectroscopic techniques and density functional theory calculation to study how the difference of substituents affects their hydrogen bonding ability. Infrared spectra in the OH stretching region indicate a formation of intramolecular hydrogen-bond in estriol, which may lead to weaker physiological activity among the three estrogens. We also measured electronic and infrared spectra of 1:1 hydrated clusters of estrogen. The results show a switch of stable hydration site from the phenolic OH group to the five member ring by substituting one more OH group.

  12. Vibronic spectroscopy of jet-cooled hydrogen-bonded clusters

    NASA Astrophysics Data System (ADS)

    Gerhards, M.; Kimpfel, B.; Pohl, M.; Schmitt, M.; Kleinermanns, K.

    1992-07-01

    Mass-selected, two-photon resonant ionisation spectra of supersonically cooled p-cresol · (H 2O) n and phenol · (H 2O) n are reported. Cluster spectra with one, two and three water molecules attached can be unambiguously assigned. A monotonic shift of the electronic spectra with increasing cluster size is not observed here. The spectrum of p-cresol · (H 2O) 1, is red-shifted relative to the free p-cresol spectrum, while the p-cresol · (H 2O) 2,3 electronic origins are blue-shifted relative to p-cresol · (H 2O) 1 but still lie on the red side of the monomer. Simple, highest occupied molecular orbital—lowest unoccupied molecular orbital (HOMO—LUMO) considerations based on an initio calculations show that this can be explained by the inductive effect exerted on the O-atom of p-cresol, which acts as proton donor and acceptor in the H-bonding. The blue shift of n-π* transitions of H-bonded chromophores with carbonyl groups like CH 2O · (H 2O) 1 can be explained similarly. Vibrational spectra of supersonically cooled complexes of p-cresol with H 2O and CH 3OH were further analysed by dispersed fluorescence and stimulated emission, detected by two-colour ionisation dip. In p-cresol · (H 2O) 1, progressions of the intermolecular cluster stretch vibration and its combination bands with intramolecular cluster vibrations were observed with similar frequencies in the S 0 and S 1 states. In p-cresol · (H 2O) 3, further intense intermolecular bands arise, namely the hydrogen-bridge bending and torsion vibrations. This can be attributed to the lower symmetry of these clusters. Ab initio quantum chemical calculations show p-cresol · (H 2O) 3 to have a higher H-bond stretch frequency than p-cresol · (H 2O) 1, because its (unsymmetric) cyclic structure is more rigid. A characteristic pattern of CH 3 torsional bands in p-cresol is observed with complex structures due the CH 3 torsion—overall rotation interaction. Although their appearance is similar, the spacing of

  13. Experimental evidence of O-H—S hydrogen bonding in supersonic jet

    NASA Astrophysics Data System (ADS)

    Biswal, Himansu S.; Chakraborty, Shamik; Wategaonkar, Sanjay

    2008-11-01

    Experimental evidence is presented for the O-H—S hydrogen bonding in the complexes of simple model compounds of methionine (dimethyl sulphide) and tyrosine (phenol, p-cresol, and 2-naphthol). The complexes were formed in the supersonic jet and were detected using resonantly enhanced multiphoton ionization spectroscopy. In all the complexes, the band origins for the S1-S0 electronic transition were redshifted relative to that of their respective monomers. The resonant ion depletion IR spectra of all the complexes show redshifts of 123-140 cm-1 in the O-H stretching frequency, indicating that the OH group acts as the hydrogen bond donor and sulfur as an acceptor. The density functional theory calculations also predict the stable structures in support of this and predict the redshifted O-H stretching frequency in the complex. The atoms-in-molecules and natural bond orbital calculations confirm the O-H—S hydrogen bonding interaction. The significant finding of this study is that the magnitudes of redshifts in the O-H stretch in the O-H—S hydrogen bonded complexes reported here are comparable to those reported for the O-H—O hydrogen bonded complexes where H2O acts as the H-bond acceptor, which suggests that the OH-S interaction is perhaps as strong as the OH-O interaction. To the best of our knowledge, this is the first such report on the O-H—S hydrogen bonded complexes.

  14. 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.

  15. Effects of Coaxial Air on Nitrogen-Diluted Hydrogen Jet Diffusion Flame Length and NOx Emission

    SciTech Connect

    Weiland, N.T.; Chen, R.-H.; Strakey, P.A.

    2007-10-01

    Turbulent nitrogen-diluted hydrogen jet diffusion flames with high velocity coaxial air flows are investigated for their NOx emission levels. This study is motivated by the DOE turbine program’s goal of achieving 2 ppm dry low NOx from turbine combustors running on nitrogen-diluted high-hydrogen fuels. In this study, effects of coaxial air velocity and momentum are varied while maintaining low overall equivalence ratios to eliminate the effects of recirculation of combustion products on flame lengths, flame temperatures, and resulting NOx emission levels. The nature of flame length and NOx emission scaling relationships are found to vary, depending on whether the combined fuel and coaxial air jet is fuel-rich or fuel-lean. In the absence of differential diffusion effects, flame lengths agree well with predicted trends, and NOx emissions levels are shown to decrease with increasing coaxial air velocity, as expected. Normalizing the NOx emission index with a flame residence time reveals some interesting trends, and indicates that a global flame strain based on the difference between the fuel and coaxial air velocities, as is traditionally used, is not a viable parameter for scaling the normalized NOx emissions of coaxial air jet diffusion flames.

  16. PEM-based polarimeters for industrial applications

    NASA Astrophysics Data System (ADS)

    Wang, Baoliang

    2010-11-01

    A polarimeter is an optical instrument used in the transmissive mode for determining the polarization state of a light beam, or the polarization-altering properties of a sample, such as diattenuation, retardation and depolarizion.1 (Reflective "polarimeters" are typically called ellipsometers.) Polarimeters can, thus, be broadly categorized as either light-measuring polarimeters or sample-measuring polarimeters. A light-measuring polarimeter is also known as a Stokes polarimeter, which measures the polarization state of a light beam as described by the Stokes parameters. A sample-measuring polarimeter is also known as a Mueller polarimeter, which measures the complete set or a subset of polarization-altering properties of a sample. Polarimeters can also be categorized by whether they measure the complete set of polarization properties. If a Stokes polarimeter measures all four Stokes parameters, it is called a complete Stokes polarimeter; otherwise, an incomplete or a special Stokes polarimeter. Similarly, there are complete and incomplete Mueller polarimeters. Nearly all samplemeasuring polarimeters are incomplete or special polarimeters, particularly for industrial applications. These special polarimeters bear different names. For example, a circular dichroism spectrometer, which measures the differential absorption between left and right circularly polarized light (▵A= AL - AR), is a special polarimeter for measuring the circular diattenuation of a sample; a linear birefringence measurement system is a special polarimeter for measuring the linear retardation of a sample. Polarimeters have a broad range of applications in both academic research and industrial metrology. Polarimeters are applied to chemistry, biology, physics, astronomy, material science and many other scientific areas. Polarimeters are used as metrology tools in the semiconductor, fiber telecommunication, flat panel display, pharmaceutical and many other industries. Different branches of

  17. Temperature distributions of a cesium-seeded hydrogen-oxygen supersonic free jet

    NASA Technical Reports Server (NTRS)

    Wang, S. Y.; Smith, J. M.

    1978-01-01

    The hydrogen-oxygen plasma was generated at combustion chamber pressures ranging from 0.5 to 2.0 megapascals and for various seed ratios (1 to 10 percent). The plasma was observed as the atmospheric exhaust from a Mach 2 rocket test facility. Transverse profiles of the absolute integrated intensity were measured with the optically thin CsI lines (0.5664 and 0.5636 microns) at a range of axial positions downstream of the 5-cm-diameter combustor nozzle exit. Radial profiles of the emission coefficient were obtained from the measured transverse profiles of intensity by Abel inversion. Temperatures were then determined from the emission coefficients for conditions of local thermodynamic equilibrium using particle densities generated by a two-dimensional free jet computer program. Temperature results show the inherent effects of compression and expansion pressure waves characteristic of a free jet exiting from a supersonic nozzle.

  18. Use of laser-induced spark for studying ignition stability and unburned hydrogen escaping from laminar diluted hydrogen diffusion jet flames

    NASA Astrophysics Data System (ADS)

    Phuoc, Tran X.; Chen, Ruey-Hung

    2007-08-01

    Ignition and unburned hydrogen escaping from hydrogen jet diffusion flames diluted with nitrogen up to 70% were experimentally studied. The successful ignition locations were about 2/3 of the flame length above the jet exit for undiluted flames and moved much closer to the exit for diluted flames. For higher levels of dilution or higher flow rates, there existed a region within which a diluted hydrogen diffusion flame can be ignited and burns with a stable liftoff height. This is contrary to previous findings that pure and diluted hydrogen jet diffusion cannot achieve a stable lifted flame configuration. With liftoff, the flame is noisy and short with significant amount of unburned hydrogen escaping into the product gases. If ignition is initiated below this region, the flame propagates upstream quickly and attaches to the burner rim. Results from measurements of unburned hydrogen in the combustion products showed that the amount of unburned hydrogen increased as the nitrogen dilution level was increased. Thus, hydrogen diffusion flame diluted with nitrogen cannot burn completely.

  19. 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.

  20. Structure of hydrogen-rich transverse jets in a vitiated turbulent flow

    SciTech Connect

    Lyra, Sgouria; Wilde, Benjamin; Kolla, Hemanth; Seitzman, Jerry M.; Lieuwen, Timothy C.; Chen, Jacqueline H.

    2014-11-24

    Our paper reports the results of a joint experimental and numerical study of the flow characteristics and flame structure of a hydrogen rich jet injected normal to a turbulent, vitiated crossflow of lean methane combustion products. Simultaneous high-speed stereoscopic PIV and OH PLIF measurements were obtained and analyzed alongside three-dimensional direct numerical simulations of inert and reacting JICF with detailed H2/COH2/CO chemistry. Both the experiment and the simulation reveal that, contrary to most previous studies of reacting JICF stabilized in low-to-moderate temperature air crossflow, the present conditions lead to a burner-attached flame that initiates uniformly around the burner edge. Significant asymmetry is observed, however, between the reaction zones located on the windward and leeward sides of the jet, due to the substantially different scalar dissipation rates. The windward reaction zone is much thinner in the near field, while also exhibiting significantly higher local and global heat release than the much broader reaction zone found on the leeward side of the jet. The unsteady dynamics of the windward shear layer, which largely control the important jet/crossflow mixing processes in that region, are explored in order to elucidate the important flow stability implications arising in the inert and reacting JICF. The paper concludes with an analysis of the ignition, flame characteristics, and global structure of the burner-attached flame. FurthermoreChemical explosive mode analysis (CEMA) shows that the entire windward shear layer, and a large region on the leeward side of the jet, are highly explosive prior to ignition and are dominated by non-premixed flame structures after ignition. The predominantly mixing limited nature of the flow after ignition is examined by computing the Takeno flame index, which shows that ~70% of the heat release occurs in non-premixed regions.

  1. Structure of hydrogen-rich transverse jets in a vitiated turbulent flow

    DOE PAGESBeta

    Lyra, Sgouria; Wilde, Benjamin; Kolla, Hemanth; Seitzman, Jerry M.; Lieuwen, Timothy C.; Chen, Jacqueline H.

    2014-11-24

    Our paper reports the results of a joint experimental and numerical study of the flow characteristics and flame structure of a hydrogen rich jet injected normal to a turbulent, vitiated crossflow of lean methane combustion products. Simultaneous high-speed stereoscopic PIV and OH PLIF measurements were obtained and analyzed alongside three-dimensional direct numerical simulations of inert and reacting JICF with detailed H2/COH2/CO chemistry. Both the experiment and the simulation reveal that, contrary to most previous studies of reacting JICF stabilized in low-to-moderate temperature air crossflow, the present conditions lead to a burner-attached flame that initiates uniformly around the burner edge. Significantmore » asymmetry is observed, however, between the reaction zones located on the windward and leeward sides of the jet, due to the substantially different scalar dissipation rates. The windward reaction zone is much thinner in the near field, while also exhibiting significantly higher local and global heat release than the much broader reaction zone found on the leeward side of the jet. The unsteady dynamics of the windward shear layer, which largely control the important jet/crossflow mixing processes in that region, are explored in order to elucidate the important flow stability implications arising in the inert and reacting JICF. The paper concludes with an analysis of the ignition, flame characteristics, and global structure of the burner-attached flame. FurthermoreChemical explosive mode analysis (CEMA) shows that the entire windward shear layer, and a large region on the leeward side of the jet, are highly explosive prior to ignition and are dominated by non-premixed flame structures after ignition. The predominantly mixing limited nature of the flow after ignition is examined by computing the Takeno flame index, which shows that ~70% of the heat release occurs in non-premixed regions.« less

  2. Reduction of gaseous pollutant emissions from gas turbine combustors using hydrogen-enriched jet fuel

    NASA Technical Reports Server (NTRS)

    Clayton, R. M.

    1976-01-01

    Recent progress in an evaluation of the applicability of the hydrogen enrichment concept to achieve ultralow gaseous pollutant emission from gas turbine combustion systems is described. The target emission indexes for the program are 1.0 for oxides of nitrogen and carbon monoxide, and 0.5 for unburned hydrocarbons. The basic concept utilizes premixed molecular hydrogen, conventional jet fuel, and air to depress the lean flammability limit of the mixed fuel. This is shown to permit very lean combustion with its low NOx production while simulataneously providing an increased flame stability margin with which to maintain low CO and HC emission. Experimental emission characteristics and selected analytical results are presented for a cylindrical research combustor designed for operation with inlet-air state conditions typical for a 30:1 compression ratio, high bypass ratio, turbofan commercial engine.

  3. A Hydrogen Peroxide Hot-Jet Simulator for Wind-Tunnel Tests of Turbojet-Exit Models

    NASA Technical Reports Server (NTRS)

    Runckel, Jack F.; Swihart, John M.

    1959-01-01

    A turbojet-engine-exhaust simulator which utilizes a hydrogen peroxide gas generator has been developed for powered-model testing in wind tunnels with air exchange. Catalytic decomposition of concentrated hydrogen peroxide provides a convenient and easily controlled method of providing a hot jet with characteristics that correspond closely to the jet of a gas turbine engine. The problems associated with simulation of jet exhausts in a transonic wind tunnel which led to the selection of a liquid monopropellant are discussed. The operation of the jet simulator consisting of a thrust balance, gas generator, exit nozzle, and auxiliary control system is described. Static-test data obtained with convergent nozzles are presented and shown to be in good agreement with ideal calculated values.

  4. Opposed jet burner studies of silane-methane, silane-hydrogen, and hydrogen diffusion flames with air

    NASA Technical Reports Server (NTRS)

    Pellett, G. L.; Guerra, Rosemary; Wilson, L. G.; Northam, G. B.

    1986-01-01

    An atmospheric pressure tubular opposed jet burner technique was used to characterize certain diffusion-flame transitions and associated burning rates for N2-diluted mixtures of highly-reactive fuels. The paper presents: (1) details of the technique, with emphasis on features permitting the study of flames involving pyrophoric gases and particle-forming combustion reactions; (2) discoveries on the properties of these flames which correspond to physically and chemically distinct stages of silane and hydrogen combustion; and (3) unburnt gas velocity data obtained from flames based on SiH4-CH4-N2, SiH4-H2-N2, and H2-N2 fuel mixtures, and plotted as functions of combustible-fuel mole fraction and fuel/oxygen molar input flow ratios. In addition, these burning velocity results are analyzed and interpreted.

  5. Opposed jet burner studies of silane-methane, silane-hydrogen and hydrogen diffusion flames with air

    NASA Technical Reports Server (NTRS)

    Pellett, G. L.; Guerra, Rosemary; Wilson, L. G.; Northam, G. B.

    1986-01-01

    An atmospheric pressure tubular opposed jet burner technique was used to characterize certain diffusion-flame transitions and associated burning rates for N2-diluted mixtures of highly-reactive fuels. Presented are: (1) details of the technique, with emphasis on features permitting the study of flames involving pyrophoric gases and particle-forming combustion reactions: (2) discoveries on the properties of these flames which correspond to physically and chemically distinct stages of silane and hydrogen combustion; and (3) unburnt gas velocity data obtained from flames based on SiH4-CH4-N2, SiH4-H2-N2, and H2-N2 fuel mixtures, and plotted as functions of combustible-fuel mole fraction and fuel/oxygen molar input flow ratios. In addition, these burning velocity results are analyzed and interpreted.

  6. Mixing of a Hydrogen Jet from a Wedge Shaped Injector into a Supersonic Cross Flow

    NASA Astrophysics Data System (ADS)

    Sakima, Fuminori; Arai, Takakage; Kasahara, Jiro; Murakoshi, Masaya; Ami, Takayuki; He, Fei; Sugiyama, Hiromu

    A new measurement by using a catalytic reaction on a platinum wire was conducted spatially to evaluate a mixing condition in a supersonic flow field. A spatial mixing field was created by a transverse hydrogen jet injected into a cold supersonic cross flow (Mach 1.81) through a wedge shaped injector. The half-vertical angles of 8° or 18° were chosen as that of the wedge shaped injector. These results were compared with that of a circular injector case. The results showed that this method could evaluate a spatial mixing condition. The results also clarified that a jet plume in the cases of wedge injectors penetrated higher than that of the circular injector case and separate from the lower wall when going downstream. To observe jet/supersonic flow interaction, Schlieren visualization and oil flow visualization were carried out. It was shown that the extent of the separation region around the 8° wedge injector was the smallest among those injectors. Pitot pressure measurements were also conducted. These indicated that a wedge injector scheme was more beneficial than that of a circular injector for the supersonic combustion and combustor wall cooling.

  7. Mechanisms of Flame Stabilization and Blowout in a Reacting Turbulent Hydrogen Jet in Cross-Flow

    SciTech Connect

    Kolla, H.; Grout, R. W.; Gruber, A.; Chen, J. H.

    2012-08-01

    The mechanisms contributing to flame stabilization and blowout in a nitrogen-diluted hydrogen transverse jet in a turbulent boundary layer cross-flow (JICF) are investigated using three-dimensional direct numerical simulation (DNS) with detailed chemistry. Non-reacting JICF DNS were performed to understand the relative magnitude and physical location of low velocity regions on the leeward side of the fuel jet where a flame can potentially anchor. As the injection angle is reduced from 90{sup o} to 70{sup o}, the low velocity region was found to diminish significantly, both in terms of physical extent and magnitude, and hence, its ability to provide favorable conditions for flame anchoring and stabilization are greatly reduced. In the reacting JICF DNS a stable flame is observed for 90{sup o} injection angle and, on average, the flame root is in the vicinity of low velocity magnitude and stoichiometric mixture. When the injection angle is smoothly transitioned to 75{sup o} a transient flame blowout is observed. Ensemble averaged quantities on the flame base reveal two phases of the blowout characterized by a kinematic imbalance between flame propagation speed and flow normal velocity. In the first phase dominant flow structures repeatedly draw the flame base closer to the jet centerline resulting in richer-than-stoichiometric mixtures and high velocity magnitudes. In the second phase, in spite of low velocity magnitudes and a return to stoichiometry, due to jet bending and flame alignment normal to the cross-flow, the flow velocity normal to the flame base increases dramatically perpetuating the blowout.

  8. Simultaneous temperature and multi-species measurements in opposed jet flames of nitrogen-diluted hydrogen and air

    NASA Technical Reports Server (NTRS)

    Wehrmeyer, J. A.; Cheng, T. S.; Pitz, R. W.; Nandula, S.; Wilson, L. G.; Pellett, G. L.

    1991-01-01

    A narrowband UV Raman scattering system is used to obtain measurement profiles of major and minor species concentrations, temperature, and mixture fraction in opposed jet diffusion flames. The measurement profiles can be compared to previously obtained temperature and concentration profiles (Pellett et al., 1989), obtained using CARS, and they can also be qualitatively compared to the predicted concentration and temperature profiles in pure hydrogen/air flames (Gutheil and Williams, 1990) and in diluted hydrogen/air flames (Dixon-Lewis and Missaghi, 1988; Ho and Isaac, 1991). The applied stress-rates for the two flame conditions studied are 240/s and 340/s, with respective hydrogen concentrations in the fuel jet of 0.67 and 0.83, on a mole fraction basis (0.13 and 0.26 hydrogen mass fractions, respectively).

  9. Preparation of ultrafine jet-milled powders for Nd-Fe-B sintered magnets using hydrogenation-disproportionation-desorption-recombination and hydrogen decrepitation processes

    NASA Astrophysics Data System (ADS)

    Nakamura, Michihide; Matsuura, Masashi; Tezuka, Nobuki; Sugimoto, Satoshi; Une, Yasuhiro; Kubo, Hirokazu; Sagawa, Masato

    2013-07-01

    Dy addition is used to increase the coercivity of Nd-Fe-B sintered magnets. Given that Dy is rare and expensive, a method is needed for reducing the Dy content in such magnets without decreasing their coercivity. Refining Nd2Fe14B grains is a prospective method for increasing the coercivity of Nd-Fe-B magnets. Conventional jet milling, however, cannot crush strip-casted Nd-Fe-B alloys into powders less than 1 μm in size. We report a process for preparing ultrafine jet-milled powders with an average size of 0.33 μm for Nd-Fe-B sintered magnets: a combination of hydrogenation-disproportionation-desorption-recombination, hydrogen decrepitation, and He jet milling.

  10. Mixing augmentation induced by the interaction between the oblique shock wave and a sonic hydrogen jet in supersonic flows

    NASA Astrophysics Data System (ADS)

    Huang, Wei; Tan, Jian-guo; Liu, Jun; Yan, Li

    2015-12-01

    The mixing process between the injectant and air is very important for the operation of scramjet engine, and the injectant and air should be mixed sufficiently before entering into the combustor. The three-dimensional Reynolds-average Navier-Stokes equations coupled with the SST k-ω turbulence model have been employed to investigate the interaction of the oblique shock wave and the hydrogen jet, and the influence of the wedge angle has been taken into consideration, namely the intensity of the produced oblique shock wave, as well as the jet-to-crossflow pressure ratio. In this paper, the produced oblique shock wave collides with the bottom wall upstream and downstream of the jet orifice with the variance of the wedge angle. The obtained results show that the incident shock wave makes a great difference to the mixing enhancement between the injectant and air, and there exists a critical value of the wedge angle for the scramjet engine with a certain boundary condition. This value is 20° in the range considered in the current study, and the hydrogen is brought into the separation zone upstream of the jet orifice when the wedge angle is 20°. At the same time, the produced oblique shock wave nearly collides with the Mach disk produced by the hydrogen jet.

  11. 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

  12. 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.

  13. Spectral Features in Laser Driven Proton Acceleration from Cylindrical Solid-density Hydrogen Jets

    NASA Astrophysics Data System (ADS)

    Curry, Chandra; Gauthier, Maxence; Mishra, Rohini; Kim, Jongjin; Goede, Sebastian; Propp, Adrienne; Fiuza, Frederico; Glenzer, Siegfried H.; Williams, Jackson; Ruby, John; Goyon, Clement; Pak, Art E.; Kerr, Shaun; Tsui, Ying Y.; Ramakrishna, Bhuvanesh; Aurand, Bastian; Willi, Oswald; Roedel, Christian

    2015-11-01

    The generation of monoenergetic proton beams by ultrashort high-intensity laser-plasma interactions is of great interest for applications such as stopping power measurements, fast ignition laser confinement fusion, and ion beam therapy. In general, the commonly used mechanism of target normal sheath acceleration (TNSA) does not provide the required energy spread or maximum proton energy. Here we study alternative acceleration mechanisms, which have been identified in particle in cell (PIC) simulations, to overcome the limitations of TNSA. Using the Titan laser system at the Lawrence Livermore National Laboratory, we investigate proton acceleration from wire targets and a cryogenic solid-density hydrogen jet. Due to the cylindrical geometry, TNSA is suppressed allowing other accelerations mechanisms to become observable. Quasi-monoenergetic features in laser-forward direction are observed in the proton spectrum indicating radiation-pressure-driven acceleration mechanisms. Our experimental results are accompanied by supporting PIC simulations.

  14. Analysis of opposed-jet hydrogen-air counter flow diffusion flame

    NASA Technical Reports Server (NTRS)

    Ho, Y. H.; Isaac, K. M.; Pellett, G. L.; Northam, G. B.

    1991-01-01

    An opposed-jet counterflow diffusion-flame configuration is considered for the analysis of a nitrogen-diluted hydrogen-air diffusion flame. A boundary-layer similarity solution is employed in order to reduce the governing equations to a set of equations in one independent variable. The equation set is written in the time-dependent form and solved by the finite-volume time-marching technique. This model uses detailed chemistry and accounts for the variations of Prandtl number and Lewis number as well as the effect of thermal diffusion on the flame. It is noted that a one-step model can predict several features of the flame, while the detailed-chemistry model can be used for fine-tuning the results. The present results indicate that thermal diffusion has negligible effect on the characteristics of the flame.

  15. Analysis of opposed jet hydrogen-air counter flow diffusion flame

    NASA Technical Reports Server (NTRS)

    Ho, Y. H.; Isaac, K. M.

    1989-01-01

    A computational simulation of the opposed-jet diffusion flame is performed to study its structure and extinction limits. The present analysis concentrates on the nitrogen-diluted hydrogen-air diffusion flame, which provides the basic information for many vehicle designs such as the aerospace plane for which hydrogen is a candidate as the fuel. The computer program uses the time-marching technique to solve the energy and species equations coupled with the momentum equation solved by the collocation method. The procedure is implemented in two stages. In the first stage, a one-step forward overal chemical reaction is chosen with the gas phase chemical reaction rate determined by comparison with experimental data. In the second stage, a complete chemical reaction mechanism is introduced with detailed thermodynamic and transport property calculations. Comparison between experimental extinction data and theoretical predictions is discussed. The effects of thermal diffusion as well as Lewis number and Prandtl number variations on the diffusion flame are also presented.

  16. Strategy for Realizing High-Precision VUV Spectro-Polarimeter

    NASA Astrophysics Data System (ADS)

    Ishikawa, R.; Narukage, N.; Kubo, M.; Ishikawa, S.; Kano, R.; Tsuneta, S.

    2014-12-01

    Spectro-polarimetric observations in the vacuum ultraviolet (VUV) range are currently the only means to measure magnetic fields in the upper chromosphere and transition region of the solar atmosphere. The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) aims to measure linear polarization at the hydrogen Lyman- α line (121.6 nm). This measurement requires a polarization sensitivity better than 0.1 %, which is unprecedented in the VUV range. We here present a strategy with which to realize such high-precision spectro-polarimetry. This involves the optimization of instrument design, testing of optical components, extensive analyses of polarization errors, polarization calibration of the instrument, and calibration with onboard data. We expect that this strategy will aid the development of other advanced high-precision polarimeters in the UV as well as in other wavelength ranges.

  17. Calibration of a visible polarimeter

    NASA Astrophysics Data System (ADS)

    Gibney, Mark

    2012-06-01

    The calibration of a visible polarimeter is discussed. Calibration coefficients that provide a complete linear characterization of a polarimeter are represented in this paper by the analyzer vector, where sensor response in counts is given by the dot product of the analyzer vector and the incoming Stokes vector. Using the analyzer vector to represent the effect of the sensor on the incoming Stokes vector, we can include elements of the calibration Stokes vector in the fit used to estimate the analyzer vectors/calibration coefficients. This technique allows us to alleviate some of the strict requirements usually levied on the source used to generate the calibration Stokes vectors, such as source temporal stability. Data will be shown that validate the resultant analyzer vectors/calibration coefficients, using a novel technique with a tilted glass plate. A discussion of how these techniques are applied to IR sensors will also be touched on.

  18. The Compton polarimeter for SLC

    SciTech Connect

    Fero, M.J.; The SLD Collaboration

    1992-12-01

    We report on the use of a Compton scattering based polarimeter to measure beam polarization near the e{sup +}e{sub -} interaction point at the SLAC Linear Collider (SLC). Measurement of the beam polarization to a statistical precision of {delta}P/P={plus_minus}3% requires approximately three minutes under normal conditions. An average beam polarization of 22.4{plus_minus}0.7%(syst.) was measured over the course of the 1992 polarized beam run.

  19. The Compton polarimeter for SLC

    SciTech Connect

    Fero, M.J. )

    1992-12-01

    We report on the use of a Compton scattering based polarimeter to measure beam polarization near the e[sup +]e[sub -] interaction point at the SLAC Linear Collider (SLC). Measurement of the beam polarization to a statistical precision of [delta]P/P=[plus minus]3% requires approximately three minutes under normal conditions. An average beam polarization of 22.4[plus minus]0.7%(syst.) was measured over the course of the 1992 polarized beam run.

  20. Development of an infrared polarimeter

    NASA Technical Reports Server (NTRS)

    Coffeen, D. L.

    1972-01-01

    AEROPOL infrared polarimeter was built for measurements microns between 1.1 and 3.5 microns, with a 1.5 degree field of view, using a wire grid polarization analyzer. A PbS detector is cooled by condensed Freon-13. The instrument operates under minicomputer control, giving a polarization least squares solution each 2.5 seconds. AEROPOL was flown on the NASA CV-990 aircraft, in a remote-sensing study of terrestrial cloud particle sizes and shapes.

  1. Inferring divertor plasma properties from hydrogen Balmer and Paschen series spectroscopy in JET-ILW

    NASA Astrophysics Data System (ADS)

    Lomanowski, B. A.; Meigs, A. G.; Sharples, R. M.; Stamp, M.; Guillemaut, C.; Contributors, JET

    2015-11-01

    A parametrised spectral line profile model is formulated to investigate the diagnostic scope for recovering plasma parameters from hydrogenic Balmer and Paschen series spectroscopy in the context of JET-ILW divertor plasmas. The separate treatment of Zeeman and Stark contributions in the line model is tested against the PPP-B code which accounts for their combined influence on the spectral line shape. The proposed simplified model does not fully reproduce the Stark-Zeeman features for the α and β transitions, but good agreement is observed in the line width and wing profiles, especially for n  >  5. The line model has been applied to infer radial density profiles in the JET-ILW divertor with generally good agreement between the D 5\\to 2 , 5\\to 3 , 6\\to 2 , 7\\to 2 and 9\\to 2 lines for high recycling and detached conditions. In an L-mode detached plasma pulse the Langmuir probe measurements typically underestimated the density by a factor 2-3 and overestimated the electron temperature by a factor of 5-10 compared to spectroscopically derived values. The line model is further used to generate synthetic high-resolution spectra for low-n transitions to assess the potential for parameter recovery using a multi-parametric fitting technique. In cases with 4 parameter fits with a single Maxwellian neutral temperature component the D 4\\to 3 line yields the best results with parameter estimates within 10% of the input values. For cases with 9 parameter fits inclusive of a multi-component neutral velocity distribution function the quality of the fits is degraded. Simultaneous fitting of the D 3\\to 2 and 4\\to 3 profiles improves the fit quality significantly, highlighting the importance of complementary spectroscopic measurements for divertor plasma emission studies.

  2. Combustion of hydrogen-air jets in local chemical equilibrium: A guide to the CHARNAL computer program

    NASA Technical Reports Server (NTRS)

    Spalding, D. B.; Launder, B. E.; Morse, A. P.; Maples, G.

    1974-01-01

    A guide to a computer program, written in FORTRAN 4, for predicting the flow properties of turbulent mixing with combustion of a circular jet of hydrogen into a co-flowing stream of air is presented. The program, which is based upon the Imperial College group's PASSA series, solves differential equations for diffusion and dissipation of turbulent kinetic energy and also of the R.M.S. fluctuation of hydrogen concentration. The effective turbulent viscosity for use in the shear stress equation is computed. Chemical equilibrium is assumed throughout the flow.

  3. Neutron emission from JET DT plasmas with RF heating on minority hydrogen

    NASA Astrophysics Data System (ADS)

    Henriksson, H.; Conroy, S.; Ericsson, G.; Gorini, G.; Hjalmarsson, A.; Källne, J.; Tardocchi, M.; EFDA-JET Workprogramme, contributors to the

    2002-07-01

    The neutron emission spectrum from d+t→α+n reactions has been measured as a means to study the plasma response to radio frequency (RF) power coupled to hydrogen and deuteron minority components (through fundamental and second harmonic, respectively) in a tritium discharge at JET. The spectrum was measured with the magnetic proton recoil spectrometer and was analysed in terms of two spectral components due to thermal (TH) and high-energy (HE) deuterons interacting with the bulk ion population of thermal tritons. The results were used to derive information on the deuteron population in terms of temperatures (TTH and THE) as well as corresponding particle and kinetic energy densities of the plasma; the bulk ion temperature (Ti = TTH) was determined both before (with Ohmic heating only) and during the RF pulse. Similar information on protons was derived from other measurements in order to estimate the different RF effects on protons and deuterons. This paper illustrates qualitatively the type of empirical ion kinetic information that can be obtained from neutron emission spectroscopy; the data serves as a basis for comparison with results of predictive and interpretative models on RF effects in plasmas.

  4. Analysis of a Cylindrical Specimen Heated by an Impinging Hot Hydrogen Jet

    NASA Technical Reports Server (NTRS)

    Wang, Ten-See; Luong, Van; Foote, John; Litchford, Ron; Chen, Yen-Sen

    2006-01-01

    A computational conjugate heat transfer methodology was developed, as a first step towards an efficient and accurate multiphysics, thermo-fluid computational methodology to predict environments for hypothetical solid-core, nuclear thermal engine thrust chamber and components. A solid conduction heat transfer procedure was implemented onto a pressure-based, multidimensional, finite-volume, turbulent, chemically reacting, thermally radiating, and unstructured grid computational fluid dynamics formulation. The conjugate heat transfer of a cylindrical material specimen heated by an impinging hot hydrogen jet inside an enclosed test fixture was simulated and analyzed. The solid conduction heat transfer procedure was anchored with a standard solid heat transfer code. Transient analyses were then performed with ,variable thermal conductivities representing three composites of a material utilized as flow element in a legacy engine test. It was found that material thermal conductivity strongly influences the transient heat conduction characteristics. In addition, it was observed that high thermal gradient occur inside the cylindrical specimen during an impulsive or a 10 s ramp start sequence, but not during steady-state operations.

  5. Ablation of carbonaceous materials in a hydrogen-helium arc-jet flow

    NASA Technical Reports Server (NTRS)

    Park, C.; Lundell, J. H.; Green, M. J.; Winovich, W.; Covington, M. A.

    1983-01-01

    The stagnation-point ablation rates of a graphite, a carbon-carbon composite, and four carbon-phenolic materials are measured in an arc-jet wind tunnel with a 50% hydrogen-50% helium mixture as the test gas. Flow environments are determined through measurements of static and impact pressures, heat-transfer rates to a calorimeter, and radiation spectra, and through numerical calculation of the flow through the wind tunnel, spectra, and heat-transfer rates. The environments so determined are: impact pressure approx. 3 atm, Mach number approx. 2.1, convective heat-transfer rate approx. 14 kw/sq cm, and radiative heat-transfer rate approx. 7 kw/sq cm in the absence of ablation. Ablation rates are determined from the measured rates of mass loss and recession of the ablation specimens. Compared with the predicted ablation rates obtained by running RASLE and CMA codes, the measured rates are higher by about 15% for all tested materials.

  6. Analysis of turbulent free-jet hydrogen-air diffusion flames with finite chemical reaction rates

    NASA Technical Reports Server (NTRS)

    Sislian, J. P.; Glass, I. I.; Evans, J. S.

    1979-01-01

    A numerical analysis is presented of the nonequilibrium flow field resulting from the turbulent mixing and combustion of an axisymmetric hydrogen jet in a supersonic parallel ambient air stream. The effective turbulent transport properties are determined by means of a two-equation model of turbulence. The finite-rate chemistry model considers eight elementary reactions among six chemical species: H, O, H2O, OH, O2 and H2. The governing set of nonlinear partial differential equations was solved by using an implicit finite-difference procedure. Radial distributions were obtained at two downstream locations for some important variables affecting the flow development, such as the turbulent kinetic energy and its dissipation rate. The results show that these variables attain their peak values on the axis of symmetry. The computed distribution of velocity, temperature, and mass fractions of the chemical species gives a complete description of the flow field. The numerical predictions were compared with two sets of experimental data. Good qualitative agreement was obtained.

  7. Analysis of turbulent free jet hydrogen-air diffusion flames with finite chemical reaction rates

    NASA Technical Reports Server (NTRS)

    Sislian, J. P.

    1978-01-01

    The nonequilibrium flow field resulting from the turbulent mixing and combustion of a supersonic axisymmetric hydrogen jet in a supersonic parallel coflowing air stream is analyzed. Effective turbulent transport properties are determined using the (K-epsilon) model. The finite-rate chemistry model considers eight reactions between six chemical species, H, O, H2O, OH, O2, and H2. The governing set of nonlinear partial differential equations is solved by an implicit finite-difference procedure. Radial distributions are obtained at two downstream locations of variables such as turbulent kinetic energy, turbulent dissipation rate, turbulent scale length, and viscosity. The results show that these variables attain peak values at the axis of symmetry. Computed distributions of velocity, temperature, and mass fraction are also given. A direct analytical approach to account for the effect of species concentration fluctuations on the mean production rate of species (the phenomenon of unmixedness) is also presented. However, the use of the method does not seem justified in view of the excessive computer time required to solve the resulting system of equations.

  8. Statistically advanced, self-similar, radial probability density functions of atmospheric and under-expanded hydrogen jets

    NASA Astrophysics Data System (ADS)

    Ruggles, Adam J.

    2015-11-01

    This paper presents improved statistical insight regarding the self-similar scalar mixing process of atmospheric hydrogen jets and the downstream region of under-expanded hydrogen jets. Quantitative planar laser Rayleigh scattering imaging is used to probe both jets. The self-similarity of statistical moments up to the sixth order (beyond the literature established second order) is documented in both cases. This is achieved using a novel self-similar normalization method that facilitated a degree of statistical convergence that is typically limited to continuous, point-based measurements. This demonstrates that image-based measurements of a limited number of samples can be used for self-similar scalar mixing studies. Both jets exhibit the same radial trends of these moments demonstrating that advanced atmospheric self-similarity can be applied in the analysis of under-expanded jets. Self-similar histograms away from the centerline are shown to be the combination of two distributions. The first is attributed to turbulent mixing. The second, a symmetric Poisson-type distribution centered on zero mass fraction, progressively becomes the dominant and eventually sole distribution at the edge of the jet. This distribution is attributed to shot noise-affected pure air measurements, rather than a diffusive superlayer at the jet boundary. This conclusion is reached after a rigorous measurement uncertainty analysis and inspection of pure air data collected with each hydrogen data set. A threshold based upon the measurement noise analysis is used to separate the turbulent and pure air data, and thusly estimate intermittency. Beta-distributions (four parameters) are used to accurately represent the turbulent distribution moments. This combination of measured intermittency and four-parameter beta-distributions constitutes a new, simple approach to model scalar mixing. Comparisons between global moments from the data and moments calculated using the proposed model show excellent

  9. Laser-based capillary polarimeter.

    PubMed

    Swinney, K; Hankins, J; Bornhop, D J

    1999-01-01

    A laser-based capillary polarimeter has been configured to allow for the detection of optically active molecules in capillary tubes with a characteristic inner diameter of 250 microm and a 39-nL (10(-9)) sample volume. The simple optical configuration consists of a HeNe laser, polarizing optic, fused-silica capillary, and charge-coupled device (CCD) camera in communication with a laser beam analyzer. The capillary scale polarimeter is based on the interaction between a polarized laser beam and a capillary tube, which results in a 360 degree fan of scattered light. This array of scattered light contains a set of interference fringe, which respond in a reproducible manner to changes in solute optical activity. The polarimetric utility of the instrument will be demonstrated by the analysis of two optically active solutes, R-mandelic acid and D-glucose, in addition to the nonoptically active control, glycerol. The polarimetric response of the system is quantifiable with detection limits facilitating 1.7 x 10(-3) M or 68 x 10(-12) nmol (7 psi 10(-9) g) sensitivity. PMID:11315158

  10. POLARIZED HYDROGEN JET TARGET FOR MEASUREMENT OF RHIC PROTON BEAM POLARIZATION.

    SciTech Connect

    MAKDISI,Y.; WISE,T.; CHAPMAN,M.; GRAHAM,D.; KPONOU,A.; MAHLER,G.; MENG,W.; NASS,A.; RITTER,J.

    2005-01-28

    The performance and unique features of the RHIC polarized jet target and our solutions to the important design constraints imposed on the jet by the RHIC environment are described. The target polarization and thickness were measured to be 0.924 {+-} 2% and 1.3 {+-} 0.2 x 10{sup 12} atoms/cm{sup 2} respectively.

  11. Equilibrium chemical reaction of supersonic hydrogen-air jets (the ALMA computer program)

    NASA Technical Reports Server (NTRS)

    Elghobashi, S.

    1977-01-01

    The ALMA (axi-symmetrical lateral momentum analyzer) program is concerned with the computation of two dimensional coaxial jets with large lateral pressure gradients. The jets may be free or confined, laminar or turbulent, reacting or non-reacting. Reaction chemistry is equilibrium.

  12. 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.

  13. Polarimeter for high energy photons

    NASA Astrophysics Data System (ADS)

    Wojtsekhowski, Bogdan; Vlahovic, Branislav; Tedeschi, David; Danagulian, Samuel; Litvienko, Vladimir; Pinayev, Igor

    1999-11-01

    The physics program at TJNAF includes fundamental experiments with polarized photon beam in few GeV energy range. Development of the Polarimeter for use in Hall B experiments is the subject of present abstract. We have proposed to take advantage of the recent progress in silicon micro strip detectors for measurement of the geometry and angle correlation in electron positron pair production from an amorphous converter. A detailed analysis of the setup including MC simulation shows an experimental asymmetry σ_allel/σ_⊥ ~ 1.7 in a wide range of the photon energies. This asymmetry value is confirmed by our experimental results obtained using 100 percent polarized 40 MeV γ rays at Duke FEL.

  14. 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.

  15. Development of cosmic x-ray polarimeter

    NASA Astrophysics Data System (ADS)

    Hayato, Asami; Tamagawa, Toru; Tsunoda, Naoko; Hashimoto, Shigehira; Miyamoto, Masao; Kohama, Mitsuhiro; Tokanai, Fuyuki; Hamagaki, Hideki; Inuzuka, Masahide; Miyasaka, Hiromasa; Sakurai, Ikuya; Makishima, Kazuo

    2006-06-01

    We present a performance study of a cosmic X-ray polarimeter which is based on the photoelectric effect in gas, and sensitive to a few to 30 keV range. In our polarimeter, the key device would be the 50 μm pitch Gas Electron Multiplier (GEM). We have evaluated the modulation factor using highly polarized X-ray, provided by a synchrotron accelerator. In the analysis, we selected events by the eccentricity of the charge cloud of the photoelectron track. As a result, we obtained the relationship between the selection criteria for the eccentricity and the modulation factors; for example, when we selected the events which have their eccentricity of > 0.95, the polarimeter exhibited with the modulation factor of 0.32. In addition, we estimated the Minimum Detectable Polarization degree (MDP) of Crab Nebula with our polarimeter and found 10 ksec observation is enough to detect the polarization, if we adopt suitable X-ray mirrors.

  16. Stokes, the Chicago far-infrared polarimeter

    NASA Technical Reports Server (NTRS)

    Platt, S. R.; Dotson, J. L.; Dowell, C. Darren; Hildebrand, Roger H.; Schleuning, D.; Novak, Giles

    1995-01-01

    The far-infrared polarimeter, Stokes, has produced hundreds of measurements of the polarized emission from Galactic clouds. This paper gives examples of the results and describes the design and performance of the instrument.

  17. COMMISSIONING CNI PROTON POLARIMETERS IN RHIC.

    SciTech Connect

    HUANG,H.; BRAVAR,A.; LI,Z.; MACKAY,W.W.; MAKDISI,Y.; RESCIA,S.; ROSER,T.; SURROW,B.; BUNCE,G.; DESHPANDE,A.; GOTO,Y.; ET AL

    2002-06-02

    Two polarimeters based on proton carbon elastic scattering in the Coulomb Nuclear Interference (CNI) region have been installed and commissioned in the Blue and Yellow rings of RHIC during the first RHIC polarized proton collider run. Each polarimeter consists of ultra-thin carbon targets and six silicon detectors. With newly developed wave form digitizers, they provide fast and reliable polarization information for both rings.

  18. Combustion rate limits of hydrogen plus hydrocarbon fuel: Air diffusion flames from an opposed jet burner technique

    NASA Technical Reports Server (NTRS)

    Pellett, Gerald L.; Guerra, Rosemary; Wilson, Lloyd G.; Reeves, Ronald N.; Northam, G. Burton

    1987-01-01

    Combustion of H2/hydrocarbon (HC) fuel mixtures may be considered in certain volume-limited supersonic airbreathing propulsion applications. Effects of HC addition to H2 were evaluated, using a recent argon-bathed, coaxial, tubular opposed jet burner (OJB) technique to measure the extinction limits of counterflow diffusion flames. The OJB flames were formed by a laminar jet of (N2 and/or HC)-diluted H2 mixture opposed by a similar jet of air at ambient conditions. The OJB data, derived from respective binary mixtures of H2 and methane, ethylene, or propane HCs, were used to characterize BLOWOFF and RESTORE. BLOWOFF is a sudden breaking of the dish-shaped OJB flame to a stable torus or ring shape, and RESTORE marks sudden restoration of the central flame by radial inward flame propagation. BLOWOFF is a measure of kinetically-limited flame reactivity/speed under highly stretched, but relatively ideal impingement flow conditions. RESTORE measures inward radial flame propagation rate, which is sensitive to ignition processes in the cool central core. It is concluded that relatively small molar amounts of added HC greatly reduce the reactivity characteristics of counterflow hydrogen-air diffusion flames, for ambient initial conditions.

  19. Plasma behaviour with hydrogen supersonic molecular beam and cluster jet injection in the HL-2A tokamak

    NASA Astrophysics Data System (ADS)

    Yao, Lianghua; Feng, Beibing; Chen, Chengyuan; Shi, Zhongbin; Yuan, Baoshan; Zhou, Yan; Duan, Xuru; Sun, Hongjuan; Lu, Jie; Jiao, Yiming; Ni, Guoquan; Lu, Haiyang; Xiao, Weiwen; Li, Wei; Pan, Yudong; Hong, Wenyu; Ran, Hong; Ding, Xuantong; Liu, Yong

    2007-11-01

    The experimental results of low pressure supersonic molecular beam injection (SMBI) fuelling on the HL-2A closed divertor indicate that during the period of pulsed SMBI the power density convected at the target plate surfaces was 0.4 times of that before or after the beam injection. An empirical scaling law used for the SMBI penetration depth for the HL-2A plasma was obtained. The cluster jet injection (CJI) is a new fuelling method which is based on and developed from the experiments of SMBI in the HL-1M tokamak. The hydrogen clusters are produced at liquid nitrogen temperature in a supersonic adiabatic expansion of moderate backing pressure gases into vacuum through a Laval nozzle and are measured by Rayleigh scattering. The measurement results have shown that the averaged cluster size of as large as hundreds of atoms was found at the backing pressures of more than 0.1 MPa. Multifold diagnostics gave coincidental evidence that when there was hydrogen CJI in the HL-2A plasma, a great deal of particles from the jet were deposited at a terminal area rather than uniformly ablated along the injecting path. SMB with clusters, which are like micro-pellets, will be of benefit for deeper fuelling, and its injection behaviour was somewhat similar to that of pellet injection. Both the particle penetration depth and the fuelling efficiency of the CJI were distinctly better than that of the normal SMBI under similar discharge operation. During hydrogen CJI or high-pressure SMBI, a combination of collision and radiative stopping forced the runaway electrons to cool down to thermal velocity due to such a massive fuelling.

  20. A 100-micron polarimeter for the Kuiper Airborne Observatory

    SciTech Connect

    Novak, G.; Gonatas, D.P.; Hildebrand, R.H.; Platt, S.R.

    1989-02-01

    Consideration is given to the design and performance of the 100-micron polarimeter proposed for use on the NASA Kuiper Airborne Observatory. The polarimeter specifications are listed. The polarimeter design and data reduction techniques are based on the work of Hildebrand et al. (1984) and Dragovan (1986). The polarimeter has an improved signal-to-noise ratio and systematic measurement errors below 0.2 percent. 20 refs.

  1. A 100-micron polarimeter for the Kuiper Airborne Observatory

    NASA Technical Reports Server (NTRS)

    Novak, G.; Gonatas, D. P.; Hildebrand, R. H.; Platt, S. R.

    1989-01-01

    Consideration is given to the design and performance of the 100-micron polarimeter proposed for use on the NASA Kuiper Airborne Observatory. The polarimeter specifications are listed. The polarimeter design and data reduction techniques are based on the work of Hildebrand et al. (1984) and Dragovan (1986). The polarimeter has an improved signal-to-noise ratio and systematic measurement errors below 0.2 percent.

  2. Opposed jet burner studies of hydrogen combustion with pure and N2, NO-contaminated air

    NASA Technical Reports Server (NTRS)

    Guerra, Rosemary; Pellett, Gerald L.; Northam, G. Burton; Wilson, Lloyd G.

    1987-01-01

    A counterflow diffusion flame formed by an argon-bathed tubular-opposed jet burner (OJB) was used to determine the 'blowoff' and 'restore' combustion characteristics for jets of various H2/N2 mixtures and for jets of air contaminated by NO (which normally occurs in high-enthalpy airflows supplied to hypersonic test facilities for scramjet combustors). Substantial divergence of 'blowoff' and 'restore' limits occurred as H2 mass flux, M(H)2, increased, the H2 jet became richer, and the M(air)/M(H2 + N2) ratio increased from 1 to 3 (molar H2/O2 from 1 to 16). Both OJB limits were sensitive to reactant composition. One to six percent NO in air led to significant N2-corrected decreases in the M(H2) values for 'blowoff' (2-8 percent) and 'restore' (6-12 percent) for mole fractions of H2 ranging from 0.5 to 0.95. However, when H2/O2 was held constant, all N2-corrected changes in M(H2) were negligible.

  3. Experimental research on electric propulsion. Note 7: Analysis of the performance of an arc-jet driven by means of hydrogen and nitrogen

    NASA Technical Reports Server (NTRS)

    Robotti, A. C.; Oggero, M.

    1984-01-01

    Experiments which use a new type of arc-jet, characterized by composite electromagnetic and vortex stabilization and propelled by hydrogen and nitrogen in turn are described. The electrical characteristics of the arc and the loss of heat through the electrodes is emphasized.

  4. Noise Source for Calibrating a Microwave Polarimeter

    NASA Technical Reports Server (NTRS)

    Piepmeier, Jeffrey R.; Kim, Edward J.

    2006-01-01

    A correlated-noise source has been developed for use in calibrating an airborne or spaceborne Earth-observing correlation microwave polarimeter that operates in a in a pass band that includes a nominal frequency of 10.7 GHz. Deviations from ideal behavior of the hardware of correlation polarimeters are such as to decorrelate the signals measured by such an instrument. A correlated-noise source provides known input signals, measurements of which can be processed to estimate and correct for the decorrelation effect.

  5. JET-SHOCKED H{sub 2} AND CO IN THE ANOMALOUS ARMS OF MOLECULAR HYDROGEN EMISSION GALAXY NGC 4258

    SciTech Connect

    Ogle, P. M.; Lanz, L.; Appleton, P. N.

    2014-06-20

    We present a Spitzer Infrared Spectrograph map of H{sub 2} emission from the nearby galaxy NGC 4258 (Messier 106). The H{sub 2} emission comes from 9.4 ± 0.4 × 10{sup 6} M {sub ☉} of warm molecular hydrogen heated to 240-1040 K in the inner anomalous arms, a signature of jet interaction with the galaxy disk. The spectrum is that of a molecular hydrogen emission galaxy (MOHEG), with a large ratio of H{sub 2} over 7.7 μm polycyclic aromatic hydrocarbon emission (0.37), characteristic of shocked molecular gas. We find close spatial correspondence between the H{sub 2} and CO emission from the anomalous arms. Our estimate of cold molecular gas mass based on CO emission is 10 times greater than our estimate of 1.0 × 10{sup 8} M {sub ☉} based on dust emission. We suggest that the X {sub CO} value is 10 times lower than the Milky Way value because of high kinetic temperature and enhanced turbulence. The H{sub 2} disk has been overrun and is being shocked by the jet cocoon, and much of the gas originally in the disk has been ejected into the galaxy halo in an X-ray hot outflow. We measure a modest star formation rate of 0.08 M {sub ☉} yr{sup –1} in the central 3.4 kpc{sup 2} that is consistent with the remaining gas surface density.

  6. 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.

  7. 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.

  8. 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.

  9. Design of channeled partial Mueller matrix polarimeters.

    PubMed

    Alenin, Andrey S; Scott Tyo, J

    2016-06-01

    In this paper, we introduce a novel class of systems called channeled partial Mueller matrix polarimeters (c-pMMPs). Their analysis benefits greatly by drawing from the concepts of generalized construction of channeled polarimeters as described by the modulation matrix. The modulation matrix resembles that of the data reduction method of a conventional polarimeter, but instead of using Mueller vectors as the bases, attention is focused on the Fourier properties of the measurement conditions. By leveraging the understanding of the measurement's structure, its decomposition can be manipulated to reveal noise resilience and information about the polarimeter's ability to measure the aspect of polarization that are important for any given task. We demonstrate the theory with a numerical optimization that designs c-pMMPs for the task of monitoring the damage state of a material as presented earlier by Hoover and Tyo [Appl. Opt.46, 8364 (2007)APOPAI0003-693510.1364/AO.46.008364]. We select several example systems that produce a fewer-than-full-system number of channels yet retain the ability to discriminate objects of interest. Their respective trade-offs are discussed. PMID:27409432

  10. Polarimeter provides transient response in nanosecond range

    NASA Technical Reports Server (NTRS)

    Johnston, A. R.

    1967-01-01

    Conventional polarimeter with a Senarmont compensator improves transient response and eliminates manual manipulation. A sampled photomultiplier output is fed to a low pass filter, resulting in a signal representing the optical state existing at the instant of sampling. With this technique, an unknown transient-induced retardation can be measured.

  11. Polarimeter blind deconvolution using image diversity

    NASA Astrophysics Data System (ADS)

    Strong, David M.

    This research presents an algorithm that improves the ability to view objects using an electro-optical imaging system with at least one polarization sensitive channel in addition to the primary channel. Following the review of historical methodologies applicable to this research area, the statistical Cramer-Rio lower bound (CRLB) is developed for a two- channel polarimeter. The CRLB is developed using the system's ability to resolve two point sources in the presence of atmospheric turbulence. The bounds show that such a polarimeter has an advantage over previous imaging methods at smaller separations. A small optical laboratory is set up to generate a set of calibrated images for verification of the simulation results and validation of algorithm development. Defocus is the aberration chosen for algorithm development and testing due to its significant presence when imaging through turbulence and its ease of production in the laboratory. An innovative algorithm for detection and estimation of the defocus aberration present in an image is also developed. Using a known defocus aberration, an iterative polarimeter deconvolution algorithm is developed using a generalized expectation-maximization (GEM) model that produces results as predicted by the CRLB results. Using an example bar target set with a degree of polarization of one, the polarimeter deconvolution algorithm can resolve the two bars down to half the bar separation as the Richardson-Lucy (RL) algorithm can do. In addition, a fidelity metric is used that shows the polarimeter deconvolution algorithm deconvolves simulated targets with approximately half of the error present in objects deconvolved using the RL algorithm. The polarimeter deconvolution algorithm is extended to an iterative polarimeter multiframe blind deconvolution (PMFBD) algorithm with an unknown aberration. Using both simulated and laboratory images, the results of the new PMFBD algorithm clearly outperforms an RL-based MFBD algorithm. The

  12. RINGO3: a multi-colour fast response polarimeter

    NASA Astrophysics Data System (ADS)

    Arnold, D. M.; Steele, I. A.; Bates, S. D.; Mottram, C. J.; Smith, R. J.

    2012-09-01

    GRB jets contain rapidly moving electrons which will spiral around magnetic field lines. This causes them to emit polarized synchrotron emission. We have built a series of polarimeters (RINGO and RINGO2) to investigate this by measuring the polarization of optical light from GRBs at a certain single wavelength. The instruments are mounted on the Liverpool Telescope, which is a fully robotic (i.e. unmanned) telescope on La Palma which reacts to triggers from satellites such as the NASA SWIFT mission. This has had great success, with the first ever detections of early time optical polarization being made. In addition, the first measurements of the change in optical polarization from a GRB as the jet expands have recently been obtained. In this paper we describe the design and construction of RINGO3. This will be a multi-colour instrument that can observe simultaneously at three wavelengths. By doing so we will be able to unambiguously identify where in the burst the polarized emission is coming from. This will allow us to distinguish between three possibilities: (1) Magnetic instabilities generated in the shock front, (2) Line of sight effects and (3) Large-scale magnetic fields present throughout the relativistic outflow. The instrument design combines a rapidly rotating polaroid, specially designed polarization insensitive dichroic mirrors and three electron multiplying CCD cameras to provide simultaneous wavelength coverage with a time resolution of 1 second.

  13. Enhancement of injection and acceleration of electrons in a laser wakefield accelerator by using an argon-doped hydrogen gas jet and optically preformed plasma waveguide

    SciTech Connect

    Ho, Y.-C.; Hung, T.-S.; Chen, S.-Y.; Chou, M.-C.; Yen, C.-P.; Wang, J.; Chu, H.-H.; Lin, J.-Y.

    2011-06-15

    A systematic experimental study on injection of electrons in a gas-jet-based laser wakefield accelerator via ionization of dopant was conducted. The pump-pulse threshold energy for producing a quasi-monoenergetic electron beam was significantly reduced by doping the hydrogen gas jet with argon atoms, resulting in a much better spatial contrast of the electron beam. Furthermore, laser wakefield electron acceleration in an optically preformed plasma waveguide based on the axicon-ignitor-heater scheme was achieved. It was found that doping with argon atoms can also lower the pump-pulse threshold energy in this experimental configuration.

  14. 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.

  15. Three-dimensional computations of transverse hydrogen jet combustion in a supersonic airstream

    NASA Technical Reports Server (NTRS)

    Uenishi, K.; Rogers, R. C.; Northam, G. B.

    1987-01-01

    A computational fluid dynamics (CFD) code is being developed to compute the mixing and combustion of hydrogen fuel in the turbulent flow fields of supersonic combustion ramjets (scramjet). The code solves the three-dimensional Reynolds time-averaged complete Navier-Stokes equations including transport equations for a four species, two reaction, global finite rate chemistry model. The code was applied to the case of transverse injection of hydrogen from a sonic circular orifice into a supersonic airstream. The equations were numerically integrated using MacCormack's explicit method, and the algebraic eddy viscosity model of Baldwin-Lomax was used to model the turbulence. In the species transport and energy equations, diffusion coefficients based on Fick's Law and an assumption of unit Lewis number were applied. Computed features of the three-dimensional flow field are depicted by static pressure, static temperature, mass fraction of species, and velocity vectors. For engineering interest, mixing and combustion parameters were examined to assess the effect of injector diameter, injected fuel pressure, fuel-air ratio, and spacing of fuel injectors. The objective of the present paper is to demonstrate the capability of the present three-dimensional spatially elliptic, CFD code for turbulent, reacting flow. Application of the code to specific supersonic combustion configurations is planned.

  16. 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.

  17. 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.

  18. A Pair Polarimeter for High Energy Photons

    NASA Astrophysics Data System (ADS)

    Tedeschi, David; Wojtsekhowski, B.; Khandaker, M.; Klein, F.; Feldman, G.; O'Rielly, G. V.; Vlahovic, B.

    2000-10-01

    The physics program at the Thomas Jefferson National Accelerator Facility includes fundamental experiments with polarized photon beams in the GeV energy range. To measure the degree of photon polarization, a photon polarimeter based on the detection of e^+e^- pairs has been developed for use in Hall B experiments. Recent progress in silicon micro-strip detectors allows for the measurement of the angle correlation in electron-positron pair production by high energy photons incident on an amorphous converter. Theoretical calculations of the pair production process show an asymmetry σ_allel/σ_⊥ ~ 1.7 in a wide range of photon energies. Experimental results obtained from 40 MeV photons at the Duke-FEL and 300 MeV photons from the Brookhaven-LEGS facility using prototype polarimeters will be presented.

  19. 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.

  20. Hemispherical Stokes polarimeter for early cancer diagnosis

    NASA Astrophysics Data System (ADS)

    Lemaillet, Paul; Ramella-Roman, Jessica C.

    2011-03-01

    Optimal treatment of skin cancer before it reaches metastasis depends critically on early diagnosis of the melanoma. Valuable information for this diagnosis can be obtained from the analysis of skin roughness. This information can aid in determining the necessity for skin removal. For this purpose, we developed a hemispherical imaging Stokes polarimeter designed to monitor skin cancer based on a roughness assessment of the epidermis. Our setup is composed of 16 out-of-plane polarized light illuminations tubes that contain a three color LED and a vertical polarizer, a Stokes polarimeter that contains 2 liquid crystal retarders, a reference vertical polarizer and a fast acquisition camera. The Stokes polarimeter was calibrated using a set of well-known input polarization states. Each illumination polarizer was positioned using a roughness gold standard and a facet model describing the principal angle of polarization of the analyzed light as a function of the angle of incidence. A set of phantoms mimicking the optical properties of skin at 633 nm as well as skin roughness was built using wax as the bulk material, titanium dioxide as the scatterer and a black dye as the absorber. Images of these phantoms are presented and they are analyzed using a facet model.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. Design and fabrication of the All-Reflecting H-Lyman-alpha Coronagraph/Polarimeter

    NASA Technical Reports Server (NTRS)

    Hoover, Richard B.; Johnson, R. B.; 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 215.7 A - the neutral hydrogen 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.

  6. 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.

  7. 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)

  8. The Stratospheric Kinetic Inductance Polarimeter (SKIP)

    NASA Astrophysics Data System (ADS)

    Flanigan, Daniel; Ade, P.; Araujo, D.; Bradford, K. J.; Chapman, D.; Che, G.; Day, P.; Didier, J.; Doyle, S.; Eriksen, H.; Groppi, C. E.; Hillbrand, S. N.; Johnson, B.; Jones, G.; Limon, M.; Mauskopf, P.; McCarrick, H.; Miller, A. D.; Mroczkowski, T.; Reichborn-Kjennerud, B.; Smiley, B.; Sobrin, J.; Wehus, I. K.; Zmuidzinas, J.

    2014-01-01

    We discuss the Stratospheric Kinetic Inductance Polarimeter (SKIP). SKIP is a proposed balloon-borne experiment designed to study the cosmic microwave background, the cosmic infrared background, and Galactic dust emission by observing 1100 square degrees of sky in the Northern Hemisphere with launches from Kiruna, Sweden. The instrument contains 2317 single-polarization, horn-coupled, aluminum lumped-element kinetic inductance detectors (LEKIDs), which will be maintained at 100 mK by an adiabatic demagnetization refrigerator. The polarimeter will operate in two configurations, one sensitive to a spectral band centered on 150 GHz and the other sensitive to 260 and 350 GHz bands. The detector readout system is based on the ROACH-1 board, and the detectors will be biased below 300 MHz. The detector array is fed by an F/2.4 crossed-Dragone telescope with a 500 mm aperture yielding a 15 arcminute full-width half-maximum beam at 150 GHz. To minimize detector loading and maximize sensitivity, the entire optical system will be cooled to 1 K. Linearly polarized sky signals will be modulated with a metal-mesh half-wave plate that is mounted at the telescope aperture and is rotated on a superconducting magnetic bearing. The observation program consists of two or more five-day flights, and 150 GHz observations are planned to begin in 2017.

  9. A Polarimeter for SOFIA: Summary of Research

    NASA Technical Reports Server (NTRS)

    Hildebrand, Roger H.

    1999-01-01

    The purpose of this research was to study designs for a far-infrared polarimeter for SOFIA that would greatly surpass the performance of the earlier polarimeter, Stokes, used on the Kuiper Airborne Observatory. Specifically we wished to gain the sensitivity to observe much fainter objects, to provide a choice of passbands, to reduce systematic errors, and to improve the efficiency. All of these objectives were successfully addressed. The gain in sensitivity will be achieved in part by the superior capabilities of SOFIA but to an even greater extent by the incorporation of new-technology detector arrays. We are developing superconducting transition-edge detectors using the "pop-up" design conceived by Dr. Harvey Moseley. The choice of passbands is achieved by providing three alternative optical paths, each with its own spectral filter, half-wave plate, and pupil tens. A new investigation has shown that multiwavelength observations provide an essential feature of far-infrared polarimetry. The principal source of systematic errors in observations of extended objects has been unknown polarization in the reference beams. We have developed a strategy for estimating these errors.

  10. Spectral line polarimetry with a channeled polarimeter.

    PubMed

    van Harten, Gerard; Snik, Frans; Rietjens, Jeroen H H; Martijn Smit, J; Keller, Christoph U

    2014-07-01

    Channeled spectropolarimetry or spectral polarization modulation is an accurate technique for measuring the continuum polarization in one shot with no moving parts. We show how a dual-beam implementation also enables spectral line polarimetry at the intrinsic resolution, as in a classic beam-splitting polarimeter. Recording redundant polarization information in the two spectrally modulated beams of a polarizing beam-splitter even provides the possibility to perform a postfacto differential transmission correction that improves the accuracy of the spectral line polarimetry. We perform an error analysis to compare the accuracy of spectral line polarimetry to continuum polarimetry, degraded by a residual dark signal and differential transmission, as well as to quantify the impact of the transmission correction. We demonstrate the new techniques with a blue sky polarization measurement around the oxygen A absorption band using the groundSPEX instrument, yielding a polarization in the deepest part of the band of 0.160±0.010, significantly different from the polarization in the continuum of 0.2284±0.0004. The presented methods are applicable to any dual-beam channeled polarimeter, including implementations for snapshot imaging polarimetry. PMID:25089978

  11. 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.

  12. The scanning Compton polarimeter for the SLD experiment

    SciTech Connect

    Woods, M.; SLD Collaboration

    1996-10-01

    For the 1994/95 run of the SLD experiment at SLAC, a Compton polarimeter measured the luminosity-weighted electron beam polarization to be (77.2 {+-} 0.5)%. This excellent accuracy is achieved by measuring the rate asymmetry of Compton-scattered electrons near the kinematic endpoint. The polarimeter takes data continuously while the electron and positron beams are in collision and achieves a statistical precision of better than 1% in a three minute run. To calibrate the polarimeter and demonstrate its accuracy, many scans are frequently done. These include scans of the laser polarization, the detector position with respect to the kinematic edge, and the laser power.

  13. Calibration of the Liverpool Telescope RINGO3 polarimeter

    NASA Astrophysics Data System (ADS)

    Słowikowska, Aga; Krzeszowski, Krzysztof; Żejmo, Michał; Reig, Pablo; Steele, Iain

    2016-05-01

    We present an analysis of polarimetric observations of standard stars performed over the period of more than 3 yr with the RINGO3 polarimeter mounted on the Liverpool Telescope. The main objective was to determine the instrumental polarization of the RINGO3 polarimeter in three spectral energy ranges: blue (350-640 nm), green (650-760 nm) and red (770-1000 nm). The observations were conducted between 2012 and 2016. The total time span of 1126 d was split into five epochs due to the hardware changes to the observing system. Our results should be applied to calibrate all polarimetric observations performed with the RINGO3 polarimeter.

  14. 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.

  15. Analysis of an interferometric Stokes imaging polarimeter

    NASA Astrophysics Data System (ADS)

    Murali, Sukumar

    Estimation of Stokes vector components from an interferometric fringe encoded image is a novel way of measuring the State Of Polarization (SOP) distribution across a scene. Imaging polarimeters employing interferometric techniques encode SOP in- formation across a scene in a single image in the form of intensity fringes. The lack of moving parts and use of a single image eliminates the problems of conventional polarimetry - vibration, spurious signal generation due to artifacts, beam wander, and need for registration routines. However, interferometric polarimeters are limited by narrow bandpass and short exposure time operations which decrease the Signal to Noise Ratio (SNR) defined as the ratio of the mean photon count to the standard deviation in the detected image. A simulation environment for designing an Interferometric Stokes Imaging polarimeter (ISIP) and a detector with noise effects is created and presented. Users of this environment are capable of imaging an object with defined SOP through an ISIP onto a detector producing a digitized image output. The simulation also includes bandpass imaging capabilities, control of detector noise, and object brightness levels. The Stokes images are estimated from a fringe encoded image of a scene by means of a reconstructor algorithm. A spatial domain methodology involving the idea of a unit cell and slide approach is applied to the reconstructor model developed using Mueller calculus. The validation of this methodology and effectiveness compared to a discrete approach is demonstrated with suitable examples. The pixel size required to sample the fringes and minimum unit cell size required for reconstruction are investigated using condition numbers. The importance of the PSF of fore-optics (telescope) used in imaging the object is investigated and analyzed using a point source imaging example and a Nyquist criteria is presented. Reconstruction of fringe modulated images in the presence of noise involves choosing an

  16. POL-2: The SCUBA-2 Polarimeter

    NASA Astrophysics Data System (ADS)

    Bastien, P.; Bissonnette, E.; Simon, A.; Coudé, S.; Ade, P.; Savini, G.; Pisano, G.; Leclerc, M.; Bernier, S.; Landry, J.; Houde, M.; Hezareh, T.; Naylor, D. A.; Gom, B. G.; Jenness, T.; Berry, D. S.; Johnstone, D.; Matthews, B. C.

    2011-11-01

    The SCUBA-2 polarimeter is expected to be the most sensitive instrument for the detection of polarized radiation in the submillimeter regime. This will be possible by taking advantage of the extra sensitivity, imaging speed and improved image fidelity of the new SCUBA-2 camera which is being commissioned now for use on the James-Clerk-Maxwell Telescope (JCMT). POL-2 construction is now complete and the instrument has been delivered and installed on the telescope. A general update of the instrument and its capabilities are presented. Its optical and mechanical characteristics are summarized and the expected performance is compared to previous polarimetry experiments on the JCMT. Rapid modulation to eliminate atmospheric effects is being implemented.

  17. 2-Cam LWIR imaging Stokes polarimeter

    NASA Astrophysics Data System (ADS)

    Kudenov, Michael W.; Dereniak, Eustace L.; Pezzaniti, Larry; Gerhart, Grant R.

    2008-04-01

    A 2-Cam micro-bolometer imaging polarimeter operating in the LWIR is presented. The system is capable of snapshot imaging Stokes polarimetry in any one channel (S I, S II, or S 3) by taking two simultaneous measurements of a scene. For measurements of S I or S II, the instrument relies on a specially optimized wire-grid beam-splitter. For measurements of S 3, a form birefringent quarter-wave retarder is inserted into the optical path. Specifics associated with the design of the wire-grid beam-splitter and the form birefringent quarter-wave retarder will be overviewed, with inclusion of RCWA simulations. Calibration and simulation procedures, as well as calibration targets, will be highlighted, and initial data from the instrument are presented.

  18. Infrared Stokes imaging polarimeter using microbolometers

    NASA Astrophysics Data System (ADS)

    Kudenov, Michael W.; Pezzaniti, J. Larry; Dereniak, Eustace L.; Gerhart, Grant R.

    2009-08-01

    A long wave infrared (LWIR) division of amplitude imaging Stokes polarimeter is presented. For the first time, to our knowledge, application of microbolometer focal plane array (FPA) technology to polarimetry is demonstrated. The sensor utilizes a wire-grid beamsplitter with imaging systems positioned at each output to analyze two orthogonal linear polarization states simultaneously. Combined with a form birefringent wave plate, the system is capable of snapshot imaging polarimetry in any one Stokes parameter (S1, S2 or S3). Radiometric and polarimetric calibration procedures for the instrument are provided and data from the instrument are presented, demonstrating the ability to measure intensity variations corresponding to polarized emission in natural environments. As such, emission polarimetry can be exploited at significantly reduced cost, sensor size and power consumption over instruments based on more costly Mercury-Cadmium Telluride (MCT) FPA's.

  19. A Pair Polarimeter for High Energy Photons

    NASA Astrophysics Data System (ADS)

    Tedeschi, David; Wojtsekhowski, B.; Abbott, D.; Vlahovic, B.; Hotta, T.; Kohri, H.; Matsumura, T.; Mibe, T.; Nakano, T.; Yurita, T.; Zegers, R.; Khandaker, M.; Feldman, G.; O'Rielly, G. V.; Wood, M.; Asai, G.; Rudge, A.; Weilhammer, P.

    2001-10-01

    The physics program at the Thomas Jefferson National Accelerator Facility includes fundamental experiments with polarized photon beams in the GeV energy range. To measure the degree of photon polarization, a photon polarimeter based on the detection of e^+e^- pairs has been developed for use in Hall B and was recently tested at the LEPS facility at SPring-8 in Japan. The use of silicon micro-strip detectors allows for the first time the measurement of the angle correlation in electron-positron pair production by high energy photons incident on an amorphous converter. Theoretical calculations of the pair production process show an asymmetry σ_allel/σ_⊥ ~ 1.7 in a wide range of photon energies. Experimental results from the measurement of the pair asymmetry using 2 GeV photons from the SPring-8 facility will be presented.

  20. Soft x-ray polarimeter laboratory tests

    NASA Astrophysics Data System (ADS)

    Murphy, Kendrah D.; Marshall, Herman L.; Schulz, Norbert S.; Jenks, Kevin; Sommer, Sophie J. B.; Marshall, Eric A.

    2010-07-01

    Multilayer-coated optics can strongly polarize X-rays and are central to a new design of a broad-band, soft X-ray polarimeter. We have begun laboratory work to verify the performance of components that could be used in future soft X-ray polarimetric instrumentation. We have reconfigured a 17 meter beamline facility, originally developed for testing transmission gratings for Chandra, to include a polarized X-ray source, an X-ray-dispersing transmission grating, and a multilayer-coated optic that illuminates a CCD detector. The X-rays produced from a Manson Model 5, multi-anode source are polarized by a multilayer-coated flat mirror. The current configuration allows for a 180 degree rotation of the source in order to rotate the direction of polarization. We will present progress in source characterization and system modulation measurements as well as null and robustness tests.

  1. 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.

  2. Gamma-Ray Burst Polarimeter aboard IKAROS

    NASA Astrophysics Data System (ADS)

    Murakami, T.; Yonetoku, D.; Sakashita, T.; Morihara, Y.; Kikuchi, Y.; Gunji, S.; Tokairin, N.; Mihara, T.

    2010-10-01

    A GRB polarimeter was launched by H-IIA on 21 May in 2010 at JAXA Tanegashima Space Center. A GRB polarization is the best key to understand mechanism of GRB prompt emissions and also to understand the geometry of magnetic fields. The standard GRB fireball models predict the synchrotron radiation of them, thus a high degree of polarization is expected, if the magnetic field-lines are coaligned. Previously, a few of the GRB polarization detections were reported. Although they used the Compton scattering method, but their measurements were non-coincidence mode. This made their reports were somewhat unclear. This time, our detector works fully in the coincidence mode to avoid the confusion. On 21 June, GAP is switched on and the first GRB was detected on 7 July but not yet well calibrated.

  3. Gamma-Ray Burst Polarimeter aboard IKAROS

    SciTech Connect

    Murakami, T.; Yonetoku, D.; Sakashita, T.; Morihara, Y.; Kikuchi, Y.; Gunji, S.; Tokairin, N.; Mihara, T.

    2010-10-15

    A GRB polarimeter was launched by H-IIA on 21 May in 2010 at JAXA Tanegashima Space Center. A GRB polarization is the best key to understand mechanism of GRB prompt emissions and also to understand the geometry of magnetic fields. The standard GRB fireball models predict the synchrotron radiation of them, thus a high degree of polarization is expected, if the magnetic field-lines are coaligned. Previously, a few of the GRB polarization detections were reported. Although they used the Compton scattering method, but their measurements were non-coincidence mode. This made their reports were somewhat unclear. This time, our detector works fully in the coincidence mode to avoid the confusion. On 21 June, GAP is switched on and the first GRB was detected on 7 July but not yet well calibrated.

  4. 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.

  5. 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.

  6. A LIDAR POLARIMETER TECHNIQUE FOR MEASURING SUSPENDED SOLIDS IN WATER

    EPA Science Inventory

    This study investigates the capability of the lidar polarimeter to measure the concentration of suspended solids in water for a variety of measurement conditions. Previous laboratory and field measurements have demonstrated the potential of the system to measure turbidity, transm...

  7. Variable waveplate-based polarimeter for polarimetric metrology

    NASA Astrophysics Data System (ADS)

    Peinado, Alba; Lizana, Angel; Vidal, Josep; Iemmi, Claudio; Márquez, Andrés; Moreno, Ignacio; Campos, Juan

    2009-06-01

    Polarimetry is an optical technique currently used in many research fields as biomedicine, polarimetric metrology or material characterization, where the knowledge of the state of polarization of light beams and the polarizing properties of polarizing samples is required. As a consequence, in such as applications it is necessary to use polarimeters which by means of radiomentric measurements, lead to the obtaining of some important polarimetric information. As is known, polarimeters include a state of polarization detector (PSD), which is typically formed by combinations of waveplates and polarizers. Then, intensity measurements corresponding to the projection of the analyzed state of polarization upon different configurations of the PSD used, leads to the determination of the polarimetric properties of light beams. Here, we have studied and optimized a polarimeter based on PSD system containing two electronically variable retardance waveplates. The variable waveplates are based on the Liquid Crystal Display technology, allowing the implementation of a complete polarimeter without mechanical movements.

  8. A subwavelength Stokes polarimeter on a silicon chip

    NASA Astrophysics Data System (ADS)

    Espinosa Soria, A.; Rodríguez-Fortuño, Francisco J.; Griol, Amadeu; Martínez, Alejandro

    2016-04-01

    Measuring the state of polarization (SoP) of light beams is of paramount importance in many scientific and technological disciplines, including chemistry, biosensing, astronomy and optical communications. Commercial polarimeters are built by using bulky and expensive optical elements, including half-wave plates or grid polarizers, with little prospect for miniaturization. Inspired by the concept of spin-orbit coupling, here we introduce a nanophotonic polarimeter that measures the full SoP - Stokes parameters - of a light beam over an ultrabroad wavelength range. The active region of the device, formed by a metallic nanoantenna on top of a silicon waveguide crossing, is less than a square wavelength, one order of magnitude smaller than polarimeters based on metasurfaces and many orders of magnitude smaller than commercial devices. Our approach is universal and therefore applicable to any wavelength regime and technological platform, opening a new route for miniaturized polarimeters.

  9. 5 MeV Mott Polarimeter Development at Jefferson Lab

    SciTech Connect

    Price, J. S.; Sinclair, C. K.; Cardman, L. S.; Haanskneccht, J.; Mack, D. J.; Piot, P.; Assamagan, K. A.; Grames, J.

    1997-01-01

    Low energy (E{sub k}=100 keV) Mott scattering polarimeters are ill- suited to support operations foreseen for the polarized electron injector at Jefferson Lab. One solution is to measure the polarization at 5 MeV where multiple and plural scattering are unimportant and precision beam monitoring is straightforward. The higher injector beam current offsets the lower cross-sections. Recent improvements in the CEBAF injector polarimeter scattering chamber have improved signal to noise.

  10. Three-dimensional direct numerical simulation of a turbulent lifted hydrogen jet flame in a heated coflow: flame stabilization and structure

    SciTech Connect

    Chen, Jackie; Sankaran, Ramanan; Yoo, Chun S

    2009-01-01

    Direct numerical simulation (DNS) of the near field of a three-dimensional spatially developing turbulent lifted hydrogen jet flame in heated coflow is performed with a detailed mechanism to determine the stabilization mechanism and the flame structure. The DNS was performed at a jet Reynolds number of 11,000 with over 940 million grid points. The results show that auto-ignition in a fuel-lean mixture at the flame base is the main source of stabilization of the lifted jet flame. A chemical flux analysis shows the occurrence of near-isothermal chemical chain branching preceding thermal runaway upstream of the stabilization point, indicative of hydrogen auto-ignition in the second limit. The Damkoehler number and key intermediate-species behaviour near the leading edge of the lifted flame also verify that auto-ignition occurs at the flame base. At the lifted-flame base, it is found that heat release occurs predominantly through ignition in which the gradients of reactants are opposed. Downstream of the flame base, both rich-premixed and non-premixed flames develop and coexist with auto-ignition. In addition to auto-ignition, Lagrangian tracking of the flame base reveals the passage of large-scale flow structures and their correlation with the fluctuations of the flame base. In particular, the relative position of the flame base and the coherent flow structure induces a cyclic motion of the flame base in the transverse and axial directions about a mean lift-off height. This is confirmed by Lagrangian tracking of key scalars, heat release rate and velocity at the stabilization point.

  11. Spin Light Polarimeter at 12 GeV

    NASA Astrophysics Data System (ADS)

    Mohanmurthy, Prajwal; Dutta, Dipangkar

    2012-03-01

    We plan to develop a realistic design for a novel polarimeter which will go a long way in satisfying the requirements of the precision experiments planned for the 12GeV era at Jefferson National Accelerator Facility (JLAB). A polarimeter based on the asymmetry in the spacial distribution of the spin light component of synchrotron radiation will make for a fine addition to the existing Möller and Compton polarimeters. The spin light polarimeter consists of a set of wriggler magnet along the beam that generate synchrotron radiation. The spacial distribution of synchrotron radiation will be measured by an ionization chamber after being collimated. As a part of the design process, simulation of the effects of fringe field of the 3-pole wriggler magnet that forms the primary component of the polarimeter is underway. The fringe field was simulated using LANL Poisson Superfish mesh EM solver. The results from the simulation, the preliminary design parameters of the polarimeter and its impact will be discussed.

  12. A High Sensitivity Balloon-Borne Soft Gamma-ray Polarimeter PoGOLite

    NASA Astrophysics Data System (ADS)

    Kamae, Tuneyoshi; Craig, W.; Madejski, G.; Ng, J.; Tajima, H.; Varner, G.; Carlson, P.; Klamra, W.; Pearce, M.; Bjornsson, C.; Larsson, S.; Ryde, F.; Kataoka, J.; Kawai, N.; Mizuno, T.; Takahashi, T.

    2006-09-01

    Development status of a new balloon-borne polarimeter, PoGOLite, will be presented. PoGOLite is designed to detect 10% polarization of a 100 mCrab source in one 6 hour balloon observation in the 25 keV - 100 keV energy range. Its design is based on the well-type phoswich counter technology. Polarization is measured by recording Compton scattering and photo-absorption in an array of 217 phoswich detector cells made of plastic and BGO scintillators, surrounded by active BGO shields. The design has been optimized through 4 rounds of tests at synchrotron beams and a proton beam, and flight model production has began: it can reduce the large background produced by cosmic-ray particles to about 10 mCrab level in most of its energy coverage. Potential systematic instrumental bias to the polarization measurement will be removed by rotating the polarimeter telescope around its axis. We plan to observe northern sky sources including the Crab pulsar/nebula, Cygnus X-1, and Hercules X-1 in the first flight scheduled in 2009. Our future plans include long duration balloon flights from Sweden to North America, and launching within a few weeks of gamma-ray flare detection from jet sources such as Mkn 501 by GLAST.

  13. 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

  14. The effect of hydrogen bonding on torsional dynamics: a combined far-infrared jet and matrix isolation study of methanol dimer.

    PubMed

    Kollipost, F; Andersen, J; Mahler, D W; Heimdal, J; Heger, M; Suhm, M A; Wugt Larsen, R

    2014-11-01

    The effect of strong intermolecular hydrogen bonding on torsional degrees of freedom is investigated by far-infrared absorption spectroscopy for different methanol dimer isotopologues isolated in supersonic jet expansions or embedded in inert neon matrices at low temperatures. For the vacuum-isolated and Ne-embedded methanol dimer, the hydrogen bond OH librational mode of the donor subunit is finally observed at ~560 cm(-1), blue-shifted by more than 300 cm(-1) relative to the OH torsional fundamental of the free methanol monomer. The OH torsional mode of the acceptor embedded in neon is observed at ~286 cm(-1). The experimental findings are held against harmonic predictions from local coupled-cluster methods with single and double excitations and a perturbative treatment of triple excitations [LCCSD(T)] and anharmonic. VPT2 corrections at canonical MP2 and density functional theory (DFT) levels in order to quantify the contribution of vibrational anharmonicity for this important class of intermolecular hydrogen bond vibrational motion. PMID:25381521

  15. The effect of hydrogen bonding on torsional dynamics: A combined far-infrared jet and matrix isolation study of methanol dimer

    SciTech Connect

    Kollipost, F.; Heger, M.; Suhm, M. A.; Andersen, J.; Mahler, D. W.; Wugt Larsen, R.; Heimdal, J.

    2014-11-07

    The effect of strong intermolecular hydrogen bonding on torsional degrees of freedom is investigated by far-infrared absorption spectroscopy for different methanol dimer isotopologues isolated in supersonic jet expansions or embedded in inert neon matrices at low temperatures. For the vacuum-isolated and Ne-embedded methanol dimer, the hydrogen bond OH librational mode of the donor subunit is finally observed at ∼560 cm{sup −1}, blue-shifted by more than 300 cm{sup −1} relative to the OH torsional fundamental of the free methanol monomer. The OH torsional mode of the acceptor embedded in neon is observed at ∼286 cm{sup −1}. The experimental findings are held against harmonic predictions from local coupled-cluster methods with single and double excitations and a perturbative treatment of triple excitations [LCCSD(T)] and anharmonic. VPT2 corrections at canonical MP2 and density functional theory (DFT) levels in order to quantify the contribution of vibrational anharmonicity for this important class of intermolecular hydrogen bond vibrational motion.

  16. Optimization of the GRAPE Polarimeter Design

    NASA Astrophysics Data System (ADS)

    McConnell, Mark

    The Gamma Ray Polarimeter Experiment (GRAPE) is designed to investigate one of the most exotic phenomena in the universe - gamma-ray bursts (GRB). There has been intense observational and theoretical research in recent years, but research in this area has been largely focused on studies of time histories, spectra, and spatial distributions. Theoretical models show that a more complete understanding of the inner structure of GRBs, including the geometry and physical processes close to the central engine, requires the exploitation of gamma-ray polarimetry. Over the past several years, we have developed the GRAPE instrument to measure the polarization of gamma-rays from GRBs over the energy range of 50 to 500 keV. The GRAPE design is a modular one in which several independent modules are required to achieve sufficient sensitivity. A single module fits on the front end of a 2-inch square flat-panel multi-anode photomultiplier tube (MAPMT). The first operational balloon flight took in place in September of 2011 from Ft. Sumner, NM. The purpose of the 2011 flight was to validate the science capability of GRAPE by measuring the Crab polarization with a collimated array of 16 modules. The limited success of that flight led to a second validation flight (also from Ft. Sumner) in the fall of 2014, with significantly improved shielding and a larger array of modules. That flight proved too short to make a full observation of the Crab. Although we did not succeed in measuring the polarization of the Crab with a high degree of confidence, we feel that we are nonetheless prepared to move forward with our program. Our next goal is to fly GRAPE on a long duration balloon (LDB) platform to collect data on a significant sample of GRBs. Our experience with the first two balloon flights, coupled with further design efforts focused on orbital payloads, has led to an improved polarimeter concept that represents a natural evolution of the current design. It is this new concept that we are

  17. Recent trial results of an LWIR polarimeter

    NASA Astrophysics Data System (ADS)

    Connor, Barry; Carrie, Iain

    2009-05-01

    The aim of this paper is to describe the results of various trials involving a high-resolution thermal imager that has been designed to be sensitive to polarised radiation. Polarisation has the potential to discriminate man-made objects and disturbed earth from background clutter. Polarisation combined with conventional thermal imaging within the one camera offers the potential to significantly reduce false alarms in surveillance and detection applications. The camera used during the trials is a technology demonstrator developed by Thales Optronics, UK. The camera operates in the longwave infra red and has a QWIP polarisation-sensitive detector. The results presented in this paper include recent trials in the UK and USA. The aim of the trials was to assess the utility in using a LWIR polarimeter for detection of difficult objects from background clutter. Thermal and polarised images were captured and processed in order to detect anomalies. Several polarisation-based discriminative imaging techniques are applied to trials imagery. The effect of the diurnal cycle on the effectiveness of polarisation for object discrimination will be assessed.

  18. Imaging polarimetry in the LWIR with microgrid polarimeters

    NASA Astrophysics Data System (ADS)

    Tyo, J. S.

    2010-06-01

    Microgrid polarimeters have emerged over the past decade as a viable tool for performing real-time, highly accurate polarimetric imagery. A microgrid polarimeter operates by integrating a focal plane array (FPA) with an array of micropolarizing optics. Mircrogrids have the advantage of being relatively compact, rugged, and inherently spatiotemporally aligned. However, they have the single disadvantage that the various polarization measurements that go into estimating the Stokes parameters at a particular pixel are actually coming from separate locations in the field. Hence, a microgrid polarimeter performs best where there is no image information, obviating the need for an imaging polarimeter! Recently we have been working with a LWIR microgrid polarimeter at the College of Optical Sciences. Our instrument is a DRS Sensors & Targeting Systems 640 x 480 HgCdTe FPA with linear polarizers at 0°, 45°, 90°, and 135° [1]. In this paper we will review our recent results that derive methods for artifact-free reconstruction of band limited imagery.

  19. Proton Polarimeter Calibration between 82 and 217 MeV

    SciTech Connect

    Glister, J; Lee, B; Beck, A; Brash, E; Camsonne, A; Choi, S; Dumas, J; Feuerbach, R; Gilman, R; Higinbotham, D W; Jiang, X; Jones, M K; May-Tal Beck, S; McCullough, E; Paolone, M; Piasetzky, E; Roche, J; Rousseau, Y; Sarty, A J; Sawatzky, B; Strauch, S

    2009-07-01

    The proton analyzing power in carbon has been measured for energies of 82 to 217 MeV and proton scattering angles of 5 to 41 degrees. The measurements were carried out using polarized protons from the elastic scattering H(pol. e, pol. p) reaction and the Focal Plane Polarimeter (FPP) in Hall A of Jefferson Lab. A new parameterization of the FPP p-C analyzing power was fit to the data, which is in good agreement with previous parameterizations and provides an extension to lower energies and larger angles. The main conclusions are that all polarimeters to date give consistent measurements of the carbon analyzing power, independently of the details of their construction and that measuring on a larger angular range significantly improves the polarimeter figure of merit at low energies.

  20. Design of a polarimeter with two ferroelectric liquid crystal panels

    NASA Astrophysics Data System (ADS)

    Peinado, Alba; Lizana, Angel; Campos, Juan

    2013-09-01

    We present a Stokes polarimeter based on two ferroelectric liquid crystal monopixel panels. This architecture presents advantages associated to dynamic polarimeters and also, allows very fast polarization measurements. A ferroelectric liquid crystal panel can be modeled as a waveplate with a constant retardance and, with two possible orientations for its fast axis when a bipolar electrical sign is addressed. We have calibrated the optical features of our ferroelectric liquid crystal panels: retardance and rotation of the optical axis. In addition, we have carried out an optimization of the orientation of these panels in the setup in order to obtain a minimum condition number of our polarimeter and so, minimize the propagation of noise. Afterwards, we have conducted a tolerance analysis of the elements involved in the setup, focusing for a 2% of accuracy in the Stokes vectors measurements. Then, an experimental calibration is carried out and several measurements are taken in order to analyze its performance.

  1. 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).

  2. STRONG MOLECULAR HYDROGEN EMISSION AND KINEMATICS OF THE MULTIPHASE GAS IN RADIO GALAXIES WITH FAST JET-DRIVEN OUTFLOWS

    SciTech Connect

    Guillard, P.; Ogle, P. M.; Emonts, B. H. C.; Appleton, P. N.; Morganti, R.; Oosterloo, T.; Tadhunter, C.; Evans, D. A.; Evans, A. S.

    2012-03-10

    Observations of ionized and neutral gas outflows in radio galaxies (RGs) suggest that active galactic nucleus (AGN) radio jet feedback has a galaxy-scale impact on the host interstellar medium, but it is still unclear how the molecular gas is affected. Thus, it is crucial to determine the physical conditions of the molecular gas in powerful RGs to understand how radio sources may regulate the star formation in their host galaxies. We present deep Spitzer Infrared Spectrograph (IRS) high-resolution spectroscopy of eight nearby RGs that show fast H I outflows. Strikingly, all of these H I-outflow RGs have bright H{sub 2} mid-IR lines that cannot be accounted for by UV or X-ray heating. This strongly suggests that the radio jet, which drives the H I outflow, is also responsible for the shock excitation of the warm H{sub 2} gas. In addition, the warm H{sub 2} gas does not share the kinematics of the ionized/neutral gas. The mid-IR-ionized gas lines (with FWHM up to 1250 km s{sup -1} for [Ne II] 12.8 {mu}m) are systematically broader than the H{sub 2} lines, which are resolved by the IRS in Almost-Equal-To 60% of the detected lines (with FWHM up to 900 km s{sup -1}). In five sources, 3C 236, 3C 293, 3C 459, 4C 12.50, and PKS 1549-79, the [Ne II] 12.8 {mu}m line, and to a lesser extent the [Ne III] 15.5 {mu}m and [Ne V] 14.3 {mu}m lines, clearly exhibits blueshifted wings (up to -900 km s{sup -1} with respect to the systemic velocity) that match well the kinematics of the outflowing H I or ionized gas. The H{sub 2} lines do not show these broad wings, except tentative detections in 4C 12.50, 3C 459, and PKS 1549-79. This shows that, contrary to the H I gas, the H{sub 2} gas is inefficiently coupled to the AGN jet-driven outflow of ionized gas. While the dissipation of a small fraction (<10%) of the jet kinetic power can explain the turbulent heating of the molecular gas, our data show that the bulk of the warm molecular gas is not expelled from these galaxies.

  3. Quick, cheap, and beautiful x-ray polarimeter

    NASA Astrophysics Data System (ADS)

    Weisskopf, Martin C.; Elsner, Ronald F.; Joy, Marshall K.; O'dell, Stephen L.; Ramsey, Brian D.; Garmire, Gordon P.; Meszaros, Peter; Sunyaev, Rashid

    1994-11-01

    The use of x-ray polarimeters for the study of cosmic sources has been severely limited by the lack of launch opportunities. Thus far, the most significant x-ray-polarimetry experiment was performed by a device aboard the Orbiting Solar Observatory (OSO)-8 satellite in the 1970s. The next polarimetry experiment will be the Stellar X-Ray Polarimeter (SXRP), to be flown on the Russian Spectrum-X satellite in the next few years. Here we describe a simple experiment designed as a dedicated x-ray-polarimetry mission to operate in the 10 - 20 keV band and to complement scientifically the SXRP.

  4. A star-and-sky chopping polarimeter - Design and performance

    NASA Astrophysics Data System (ADS)

    Jain, S. K.; Srinivasulu, G.

    1991-09-01

    A star-and-sky chopping polarimeter is developed for accurate measurements of linear polarization of starlight in the standard astronomical photometric U, B, V, R, and I bands. The instrumental polarization, as determined by observing the standard unpolarized stars, is 0.04 percent. It is possible to use the instrument for the measurements of circular polarization as well. A Unicorn microcomputer controls the various operations of the instrument, acquires the data, and does the on-line data reduction. This paper describes the design and performance of the polarimeter.

  5. Wide field snapshot imaging polarimeter using modified Savart plates

    NASA Astrophysics Data System (ADS)

    Saito, Naooki; Odate, Satoru; Otaki, Katsura; Kubota, Masahiro; Kitahara, Rintaro; Oka, Kazuhiko

    2013-09-01

    Without moving parts, the snapshot imaging polarimeter utilizing Savart plates is capable of stable and fast measurements of spatiallly distributed Stokes parameters. To increase feasibility of the optical design, we propose modi cations that enable a wider eld-of view. By changing the Savar plates' con guration and improving the calibration procedure, the unwanted effects associated with the increase in the eld of view can be reduced. We carried out the veri cation experiments of the wide eld of view snapshot imaging polarimeter.

  6. A P + DEUTERON PROTON POLARIMETER AT 200 MEV.

    SciTech Connect

    HUANG,H.; ROSER,T.; ZELENSKI,A.; KURITA,K.; STEPHENSON,E.; TOOLE,R.

    2002-06-02

    There has been concern about the analyzing power of the p-Carbon polarimeter at the end of 200 MeV LINAC of BNL. A new polarimeter based on proton-deuteron scattering was installed and we have repeated the calibration of proton-Carbon scattering at 12 degrees and 200 MeV against proton-deuteron scattering. The result is consistent with the value of A=0.62 now used to measure the beam polarization at the end of the LINAC.

  7. DESIGN AND MEASUREMENT OF THE STOKES POLARIMETER FOR THE COSMO K-CORONAGRAPH

    SciTech Connect

    Hou Junfeng; De Wijn, Alfred G.; Tomczyk, Steven E-mail: dwijn@ucar.edu

    2013-09-01

    We present the Stokes polarimeter for the new Coronal Solar Magnetism Observatory K-coronagraph. The polarimeter can be used in two modes. In observation mode, it is sensitive to linear polarization only and operates as a ''Stokes definition'' polarimeter. In the ideal case, such a modulator isolates a particular Stokes parameter in each modulation state. For calibrations, the polarimeter can diagnose the full Stokes vector. We present here the design process of the polarimeter, analyze its tolerances with a Monte Carlo method, develop a way to align the individual elements, and measure and evaluate its performance in both modes.

  8. A Sounding Rocket Experiment for the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP)

    NASA Astrophysics Data System (ADS)

    Kubo, M.; Kano, R.; Kobayashi, K.; Bando, T.; Narukage, N.; Ishikawa, R.; Tsuneta, S.; Katsukawa, Y.; Ishikawa, S.; Suematsu, Y.; Hara, H.; Shimizu, T.; Sakao, T.; Ichimoto, K.; Goto, M.; Holloway, T.; Winebarger, A.; Cirtain, J.; De Pontieu, B.; Casini, R.; Auchère, F.; Trujillo Bueno, J.; Manso Sainz, R.; Belluzzi, L.; Asensio Ramos, A.; Štěpán, J.; Carlsson, M.

    2014-10-01

    A sounding-rocket experiment called the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) is presently under development to measure the linear polarization profiles in the hydrogen Lyman-alpha (Lyα) line at 121.567 nm. CLASP is a vacuum-UV (VUV) spectropolarimeter to aim for first detection of the linear polarizations caused by scattering processes and the Hanle effect in the Lyα line with high accuracy (0.1%). This is a fist step for exploration of magnetic fields in the upper chromosphere and transition region of the Sun. Accurate measurements of the linear polarization signals caused by scattering processes and the Hanle effect in strong UV lines like Lyα are essential to explore with future solar telescopes the strength and structures of the magnetic field in the upper chromosphere and transition region of the Sun. The CLASP proposal has been accepted by NASA in 2012, and the flight is planned in 2015.

  9. Effects of water-contaminated air on blowoff limits of opposed jet hydrogen-air diffusion flames

    NASA Technical Reports Server (NTRS)

    Pellett, Gerald L.; Jentzen, Marilyn E.; Wilson, Lloyd G.; Northam, G. Burton

    1988-01-01

    The effects of water-contaminated air on the extinction and flame restoration of the central portion of N2-diluted H2 versus air counterflow diffusion flames are investigated using a coaxial tubular opposed jet burner. The results show that the replacement of N2 contaminant in air by water on a mole for mole basis decreases the maximum sustainable H2 mass flow, just prior to extinction, of the flame. This result contrasts strongly with the analogous substitution of water for N2 in a relatively hot premixed H2-O2-N2 flame, which was shown by Koroll and Mulpuru (1986) to lead to a significant, kinetically controlled increase in laminar burning velocity.

  10. Submillimeter laser interferometer-polarimeter for plasma diagnostics

    NASA Astrophysics Data System (ADS)

    Kamenev, Yu. E.; Kiselyev, Vladimir K.; Kuleshov, E. M.; Knyaz'kov, B. N.; Kononenko, V. K.; Nesterov, P. K.; Yanovsky, M. S.

    1994-08-01

    There are presented the results of investigation of the homodyne laser interferometer-polarimeter (lambda) equals 195 micrometers made on the quasioptical element basis and designed for the synchronous determination of the plasma electron density ne and the poloidal magnetic field Bp in 'TOKAMAK' mountings of the thermonuclear fusion.

  11. 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.

  12. The Skylab ten color photoelectric polarimeter. [sky brightness

    NASA Technical Reports Server (NTRS)

    Weinberg, J. L.; Hahn, R. C.; Sparrow, J. G.

    1975-01-01

    A 10-color photoelectric polarimeter was used during Skylab missions SL-2 and SL-3 to measure sky brightness and polarization associated with zodiacal light, background starlight, and the spacecraft corona. A description is given of the instrument and observing routines together with initial results on the spacecraft corona and polarization of the zodiacal light.

  13. Twin Jet

    NASA Technical Reports Server (NTRS)

    Henderson, Brenda; Bozak, Rick

    2010-01-01

    Many subsonic and supersonic vehicles in the current fleet have multiple engines mounted near one another. Some future vehicle concepts may use innovative propulsion systems such as distributed propulsion which will result in multiple jets mounted in close proximity. Engine configurations with multiple jets have the ability to exploit jet-by-jet shielding which may significantly reduce noise. Jet-by-jet shielding is the ability of one jet to shield noise that is emitted by another jet. The sensitivity of jet-by-jet shielding to jet spacing and simulated flight stream Mach number are not well understood. The current experiment investigates the impact of jet spacing, jet operating condition, and flight stream Mach number on the noise radiated from subsonic and supersonic twin jets.

  14. 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.

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

    PubMed

    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. PMID:26827317

  16. CFD calculations of gas leak dispersion and subsequent gas explosions: validation against ignited impinging hydrogen jet experiments.

    PubMed

    Middha, Prankul; Hansen, Olav R; Grune, Joachim; Kotchourko, Alexei

    2010-07-15

    Computational fluid dynamics (CFD) tools are increasingly employed for quantifying incident consequences in quantitative risk analysis (QRA) calculations in the process industry. However, these tools must be validated against representative experimental data, involving combined release and ignition scenarios, in order to have a real predictive capability. Forschungszentrum Karlsruhe (FZK) has recently carried out experiments involving vertically upwards hydrogen releases with different release rates and velocities impinging on a plate in two different geometrical configurations. The dispersed cloud was subsequently ignited and resulting explosion overpressures recorded. Blind CFD simulations were carried out prior to the experiments to predict the results. The simulated gas concentrations are found to correlate reasonably well with observations. The overpressures subsequent to ignition obtained in the blind predictions could not be compared directly as the ignition points chosen in the experiments were somewhat different from those used in the blind simulations, but the pressure levels were similar. Simulations carried out subsequently with the same ignition position as those in the experiments compared reasonably well with the observations. This agreement points to the ability of the CFD tool FLACS to model such complex scenarios even with hydrogen as a fuel. Nevertheless, the experimental set-up can be considered to be small-scale. Future large-scale data of this type will be valuable to confirm ability to predict large-scale accident scenarios. PMID:20346585

  17. An Approach to Understanding Cohesive Slurry Settling, Mobilization, and Hydrogen Gas Retention in Pulsed Jet Mixed Vessels

    SciTech Connect

    Gauglitz, Phillip A.; Wells, Beric E.; Fort, James A.; Meyer, Perry A.

    2009-05-22

    The Hanford Waste Treatment and Immobilization Plant (WTP) is being designed and built to pretreat and vitrify a large portion of the waste in Hanford’s 177 underground waste storage tanks. Numerous process vessels will hold waste at various stages in the WTP. Some of these vessels have mixing-system requirements to maintain conditions where the accumulation of hydrogen gas stays below acceptable limits, and the mixing within the vessels is sufficient to release hydrogen gas under normal conditions and during off-normal events. Some of the WTP process streams are slurries of solid particles suspended in Newtonian fluids that behave as non-Newtonian slurries, such as Bingham yield-stress fluids. When these slurries are contained in the process vessels, the particles can settle and become progressively more concentrated toward the bottom of the vessels, depending on the effectiveness of the mixing system. One limiting behavior is a settled layer beneath a particle-free liquid layer. The settled layer, or any region with sufficiently high solids concentration, will exhibit non-Newtonian rheology where it is possible for the settled slurry to behave as a soft solid with a yield stress. In this report, these slurries are described as settling cohesive slurries.

  18. Para-hydrogen and helium cluster size distributions in free jet expansions based on Smoluchowski theory with kernel scaling

    SciTech Connect

    Kornilov, Oleg; Toennies, J. Peter

    2015-02-21

    The size distribution of para-H{sub 2} (pH{sub 2}) clusters produced in free jet expansions at a source temperature of T{sub 0} = 29.5 K and pressures of P{sub 0} = 0.9–1.96 bars is reported and analyzed according to a cluster growth model based on the Smoluchowski theory with kernel scaling. Good overall agreement is found between the measured and predicted, N{sub k} = A k{sup a} e{sup −bk}, shape of the distribution. The fit yields values for A and b for values of a derived from simple collision models. The small remaining deviations between measured abundances and theory imply a (pH{sub 2}){sub k} magic number cluster of k = 13 as has been observed previously by Raman spectroscopy. The predicted linear dependence of b{sup −(a+1)} on source gas pressure was verified and used to determine the value of the basic effective agglomeration reaction rate constant. A comparison of the corresponding effective growth cross sections σ{sub 11} with results from a similar analysis of He cluster size distributions indicates that the latter are much larger by a factor 6-10. An analysis of the three body recombination rates, the geometric sizes and the fact that the He clusters are liquid independent of their size can explain the larger cross sections found for He.

  19. The (CH2)2O-H2O hydrogen bonded complex. Ab Initio calculations and Fourier transform infrared spectroscopy from neon matrix and a new supersonic jet experiment coupled to the infrared AILES beamline of synchrotron SOLEIL.

    PubMed

    Cirtog, M; Asselin, P; Soulard, P; Tremblay, B; Madebène, B; Alikhani, M E; Georges, R; Moudens, A; Goubet, M; Huet, T R; Pirali, O; Roy, P

    2011-03-31

    A series of hydrogen bonded complexes involving oxirane and water molecules have been studied. In this paper we report on the vibrational study of the oxirane-water complex (CH(2))(2)O-H(2)O. Neon matrix experiments and ab initio anharmonic vibrational calculations have been performed, providing a consistent set of vibrational frequencies and anharmonic coupling constants. The implementation of a new large flow supersonic jet coupled to the Bruker IFS 125 HR spectrometer at the infrared AILES beamline of the French synchrotron SOLEIL (Jet-AILES) enabled us to record first jet-cooled Fourier transform infrared spectra of oxirane-water complexes at different resolutions down to 0.2 cm(-1). Rovibrational parameters and a lower bound of the predissociation lifetime of 25 ps for the v(OH)(b) = 1 state have been derived from the rovibrational analysis of the ν(OH)(b) band contour recorded at respective rotational temperatures of 12 K (Jet-AILES) and 35 K (LADIR jet). PMID:21381647

  20. Jet shielding of jet noise

    NASA Technical Reports Server (NTRS)

    Simonich, J. C.; Amiet, R. K.; Schlinker, R. H.

    1986-01-01

    An experimental and theoretical study was conducted to develop a validated first principle analysis for predicting the jet noise reduction achieved by shielding one jet exhaust flow with a second, closely spaced, identical jet flow. A generalized fuel jet noise analytical model was formulated in which the acoustic radiation from a source jet propagates through the velocity and temperature discontinuity of the adjacent shielding jet. Input variables to the prediction procedure include jet Mach number, spacing, temperature, diameter, and source frequency. Refraction, diffraction, and reflection effects, which control the dual jet directivity pattern, are incorporated in the theory. The analysis calculates the difference in sound pressure level between the dual jet configuration and the radiation field based on superimposing two independent jet noise directivity patterns. Jet shielding was found experimentally to reduce noise levels in the common plane of the dual jet system relative to the noise generated by two independent jets.

  1. Infrared depletion spectroscopy of the doubly hydrogen-bonded aniline-(tetrahydrofuran) 2 complex produced in supersonic jet

    NASA Astrophysics Data System (ADS)

    Chowdhury, Pradyot K.

    2006-01-01

    The vibrational frequencies of the N-H stretching modes of aniline after forming a strong doubly H-bonded complex with tetrahydrofuran (THF) are measured with infrared depletion spectroscopy that uses cluster-size-selective resonance-enhanced multiphoton ionization (REMPI) time-of-flight mass spectrometry. Two strong infrared absorption features observed at 3355 and 3488 cm -1 are assigned to the symmetric and antisymmetric N-H stretching vibrations of the 1:2 aniline-THF complex, respectively. The red-shifts of the N-H stretching vibrations of aniline agree with the ab initio calculated (MP2/6-31G**) aniline-(THF) 2 structure in which both aniline N-H bonds interact with the oxygen atom of THF through two hydrogen bonds. The calculated binding energy is found to be 29.6 kJ mol -1 after corrections for basis set superposition error (BSSE) and zero-point energy. The calculated structure revealed that the angle between the N-H bonds in the NH 2 group increased to 112.5° in the aniline-(THF) 2 complex from that of 109.8° in the aniline. The electronic 0-0 band origin for the S1 ← S0 transition is observed at 32,900 cm -1 in the aniline-(THF) 2 complex, giving a red-shift of 1129 cm -1 from that of the aniline molecule.

  2. Analysis of AGS E880 polarimeter data at Gy = 12.5.

    SciTech Connect

    Cadman, R.; Huang, H.; Krueger, K.; Spinka, H.; Underwood, D.

    2012-02-23

    Data were collected with the AGS internal (E880) polarimeter at G{gamma} = 12.5 during the FY04 polarized proton run. Measurements were made with forward scintillation counters in coincidence with recoil counter telescopes, permitting an absolute calibration of the polarimeter for both nylon and carbon targets. The results are summarized and they will also be useful for an absolute calibration of the AGS CNI polarimeter at G{gamma} = 12.5.

  3. Analysis of AGS E880 polarimeter data at Ggamma = 12.5

    SciTech Connect

    Cadman, R. V.; Huang, H.; Krueger, K.; Spinka, H.; Underwood, D.

    2012-01-27

    Data were collected with the AGS internal (E880) polarimeter at G{gamma} = 12.5 during the FY04 polarized proton run. Measurements were made with forward scintillation counters in coincidence with recoil counter telescopes, permitting an absolute calibration of the polarimeter for both nylon and carbon targets. The results are summarized and they will also be useful for an absolute calibration of the AGS CNI polarimeter at G{gamma} = 12.5.

  4. Optimization of retardance for a complete Stokes polarimeter

    SciTech Connect

    Sabatke, D. S.; Descour, M. R.; Dereniak, E. L.; Sweatt, W. C.; Kemme, S. A.; Phipps, G. S.

    2000-06-01

    We present two figures of merit based on singular value decomposition, which can be used to assess the noise immunity of a complete Stokes polarimeter. These are used to optimize a polarimeter featuring a rotatable retarder and a fixed polarizer. A retardance of 132 degree sign (approximately three-eighths wave) and retarder orientation angles of {+-}51.7{sup (convolution} {sup sign)} and {+-}15.1{sup (convolution} {sup sign)} are found to be optimal when four measurements are used. Use of this retardance affords a factor-of-1.5 improvement in signal-to-noise ratio over systems employing a quarter-wave plate. A geometric means of visualizing the optimization process is discussed, and the advantages of the use of additional measurements are investigated. No advantage of using retarder orientation angles spaced uniformly through 360 degree sign is found over repeated measurements made at the four retarder orientation angles. (c) 2000 Optical Society of America.

  5. Optimization of retardance for a complete Stokes polarimeter

    SciTech Connect

    Sabatke, D.S.; Descour, M.R.; Dereniak, E.L.; Sweatt, W.C.; Kemme, S.A.; Phipps, G.S.

    2000-01-13

    The authors present two figures of merit based on singular value decomposition which can be used to assess the noise immunity of a complete Stokes polarimeter. These are used to optimize a polarimeter consisting of a rotatable retarder and fixed polarizer. A retardance of 132{degree} (approximately three eights wave) and retarder orientation angles of {+-}51.7{degree} and {+-}15.1{degree} are found to be optimal when four measurements are used. Use of this retardance affords a factor of 1.5 improvement in signal-to-noise ratio over systems employing a quarter wave plate. A geometric means of visualizing the optimization process is discussed, and the advantages of the use of additional measurements are investigated. No advantage of using retarder orientation angles spaced uniformly through 360{degree} is found over repeated measurements made at the four angles given previously.

  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. 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.

  8. Compact polarimeters based on polarization-sensitive focal plane arrays

    NASA Astrophysics Data System (ADS)

    Vorobiev, Dmitry; Ninkov, Zoran

    2014-08-01

    We report on the design, fabrication and performance of the Rochester Institute of Technology Polarization Imaging Camera (RITPIC). Despite great advances in astronomical (and terrestrial remote sensing) instrumentation, the measurement of polarization of light remains challenging and infrequent. Recently, the fabrication of micropolarizer arrays has allowed the development of compact polarimeters which promise to make polarimetry more accessible. These devices are capable of measuring the degree of polarization (DoP) and angle of polarization (AoP) across a scene using a single exposure ("snapshot"). They are compact, light-weight and mechanically robust, making them ideal for deployment on space-based platforms. We present the performance of such a polarimeter and describe the kind of science that is possible with RITPIC and future generations of these revolutionary devices.

  9. Estimation of errors in partial Mueller matrix polarimeter calibration

    NASA Astrophysics Data System (ADS)

    Alenin, Andrey S.; Vaughn, Israel J.; Tyo, J. Scott

    2016-05-01

    While active polarimeters have been shown to be successful at improving discriminability of the targets of interest from their background in a wide range of applications, their use can be problematic for cases with strong bandwidth constraints. In order to limit the number of performed measurements, a number of successive studies have developed the concept of partial Mueller matrix polarimeters (pMMPs) into a competitive solution. Like all systems, pMMPs need to be calibrated in order to yield accurate results. In this treatment we provide a method by which to select a limited number of reference objects to calibrate a given pMMP design. To demonstrate the efficacy of the approach, we apply the method to a sample system and show that, depending on the kind of errors present within the system, a significantly reduced number of reference objects measurements will suffice for accurate characterization of the errors.

  10. 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.

  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. Polarimeters and Energy Spectrometers for the ILC Beam Delivery System

    SciTech Connect

    Boogert, S.; Hildreth, M.; Kafer, D.; List, J.; Monig, K.; Moffeit, K.C.; Moortgat-Pick, G.; Riemann, S.; Schreiber, H.J.; Schuler, P.; Torrence, E.; Woods, M.; /SLAC

    2009-02-24

    This article gives an overview of current plans and issues for polarimeters and energy spectrometers in the Beam Delivery System of the ILC. It is meant to serve as a useful reference for the Detector Letter of Intent documents currently being prepared. Concepts for high precision polarization and energy measurements exist. These concepts have resulted in detailed system layouts that are included in the RDR description for the Beam Delivery System. The RDR includes both upstream and downstream polarimeters and energy spectrometers for both beams. This provides needed complementarity and redundancy for achieving the precision required, with adequate control and demonstration of systematic errors. The BDS polarimeters and energy spectrometers need to be a joint effort of the ILC BDS team and the Detector collaborations, with collaboration members responsible for the performance and accuracy of the measurements. Details for this collaboration and assigning of responsibilities remain to be worked out. There is also a demonstrated need for Detector physicists to play an active role in the design and evaluation of accelerator components that impact beam polarization and beam energy capabilities, including the polarized source and spin rotator systems. A workshop was held in 2008 on ILC Polarization and Energy measurements, which resulted in a set of recommendations for the ILC design and operation. Additional input and action is needed on these from the Detector collaborations, the Research Director and the GDE. Work is continuing during the ILC engineering design phase to further optimize the polarimeter and energy spectrometer concepts and fully implement them in the ILC. This includes consideration for alternative methods, detailed design and cost estimates, and prototype and test beam activities.

  13. PHYSICS WITH A FOCAL PLANE PROTON POLARIMETER FOR HALL A AT CEBAF

    SciTech Connect

    Ron Gilman; F.T. Baker; Louis Bimbot; Ed Brash; Charles Glashausser; Mark Jones; Gerfried Kumbartzki; Sirish Nanda; Charles F. Perdrisat; Vina Punjabi; Ronald Ransome; Paul Rutt

    1994-09-01

    A focal plane polarimeter intended for the CEBAF Hall A high resolution hadron spectrometer is under construction at Rutgers University and the College of William and Mary. Experiments with focal plane polarimeters are only now beginning at electron accelerators; they play a prominent role in the list of approved experiments for Hall A. Construction of the polarimeter is in progress, it is expected to be brought to CEBAF in spring 1995. Several coincidence (e,e'p) and singles (gamma, p) measurements by the Hall A Collaboration are expected to start in 1996. In this paper we describe the polarimeter and the physics program planned for it.

  14. PolKa: A Tunable Polarimeter for Submillimeter Bolometer Arrays

    NASA Astrophysics Data System (ADS)

    Siringo, G.; Kreysa, E.; Menten, K. M.; Reichertz, L. A.

    2005-12-01

    A new polarimeter has been constructed to be used with the bolometer arrays developed at the Max-Planck-Institut für Radioastronomie in Bonn. The new polarimeter has the unique characteristic of being tunable over a wide range of wavelengths and of producing negligible absorption. It has been used at the Heinrich Hertz Telescope to measure the linear polarization of quasars and of extended sources inside our Galaxy. We detected polarization in the quasars 3C 279 and QSO B1633+382. In 3C 279 we also detected polarization variability on a time scale of a week. We also produced maps of three extended sources: the Becklin-Neugebauer/Kleinmann-Low complex in the Orion Molecular Cloud 1 (OMC 1), a filamentary cloud in OMC 3, and the massive star-forming region IRAS 05358+3543. The polarimeter has low spurious polarization and a high modulation efficiency, and the tests at the telescope show that it is well suited to become a permanent facility.

  15. A new polarimeter for (sub)millimeter bolometer arrays

    NASA Astrophysics Data System (ADS)

    Siringo, G.; Kreysa, E.; Reichertz, L. A.; Menten, K. M.

    2004-08-01

    A new polarimeter concept has been designed to be used together with the bolometer arrays developed at the Max-Planck-Institut für Radioastronomie in Bonn. The new polarimeter has the unique characteristic of being tunable over a wide range of wavelengths and of producing negligible absorption. It has been used at the Heinrich Hertz Telescope to measure the linear polarization of several quasars and of extended sources inside our Galaxy. Some results are presented here. We detected polarization in the quasars 3C 279 and QSO B1633+382. In 3C 279 we also detected polarization variability on a time scale of a week. We also produced maps of three extended sources: the Becklin-Neugebauer/Kleinmann-Low (BNKL) complex in the Orion Molecular Cloud 1 (OMC 1), a filamentary cloud in OMC 3, and the massive star-forming region IRAS 05358+3543. The polarimeter has low spurious polarization and a high modulation efficiency, and the tests at the telescope show that it is well suited to become a permanent facility.

  16. Combatting infrared focal plane array nonuniformity noise in imaging polarimeters

    NASA Astrophysics Data System (ADS)

    Ratliff, Bradley M.; Kumar, Rakesh; Black, Wiley; Boger, James K.; Tyo, J. Scott

    2005-08-01

    One of the most significant challenges in performing infrared (IR) polarimetery is the focal plane array (FPA) nonuniformity (NU) noise that is inherent in virtually all IR photodetector technologies that operate in the midwave IR (MWIR) or long-wave IR (LWIR). NU noise results from pixel-to-pixel variations in the repsonsivity of the photodetectors. This problem is especially severy in the microengineered IR FPA materials like HgCdTe and InSb, as well as in uncooled IR microbolometer sensors. Such problems are largely absent from Si based visible spectrum FPAs. The pixel response is usually a variable nonlinear response function, and even when the response is linearized over some range of temperatures, the gain and offset of the resulting response is usually highly variable. NU noise is normally corrected by applying a linear calibration to the data, but the resulting imagery still retains residual nonuniformity due to the nonlinearity of the photodetector responses. This residual nonuniformity is particularly troublesome for polarimeters because of the addition and subtraction operations that must be performed on the images in order to construct the Stokes parameters or other polarization products. In this paper we explore the impact of NU noise on full stokes and linear-polarization-only IR polarimeters. We compare the performance of division of time, division of amplitude, and division of array polarimeters in the presence of both NU and temporal noise, and assess the ability of calibration-based NU correction schemes to clean up the data.

  17. Demonstration of snapshot imaging polarimeter using modified Savart polariscopes.

    PubMed

    Cao, Qizhi; Zhang, Jing; DeHoog, Edward; Zhang, Chunmin

    2016-02-10

    In an earlier publication, [Appl. Opt.51, 5791 (2012)] we demonstrated by theoretical analysis that a snapshot imaging polarimeter using modified Savart polariscopes (MSP-SIP) is comparable in carrier frequency, signal-to-noise ratio, and spatial resolution to a snapshot imaging polarimeter using conventional Savart polariscopes. In this investigation, numerical simulation is used to demonstrate the feasibility of MSP-SIP and investigate the limitation of the filtration and the Fourier analysis decoupling the polarization information encoded through the spatial modulation. In addition, a laboratory experiment is conducted to demonstrate the validity of MSP-SIP. The MSP-SIP operates on the principle of encoding polarization information within the spatial modulation of the image. This unique technology allows all Stokes parameters to be simultaneously recorded from every spatial position in an image with a single integration period of the imaging system. The device contains no moving parts and requires no scanning, allowing it to acquire data without the motion artifacts normally associated with a scanning polarimeter. In addition to snapshot imaging and static (no moving parts) capabilities, image processing is simple, and the device is compact and miniature. Therefore, we believe that MSP-SIP will be useful in many applications, such as remote sensing and bioscience. PMID:26906358

  18. PROPOSAL FOR A CAVITY POLARIMETER AT MIT-BATES.

    SciTech Connect

    CAMERON,P.; BARRY,W.; CONTE,M.; GOLDBERG,D.A.; JACOBS,K.; LUCCIO,A.; PALAZZI,M.; PUSTERLA,M.; MACKAY,W.

    2001-06-18

    The possibility of successfully implementing a cavity polarimeter[1] has been greatly improved by the discovery[2] of a cavity mode for which the magnitude of the Stern-Gerlach force experienced by a magnetic moment traversing the cavity varies as the square of the relativistic factor gamma, so that the signal power varies as the fourth power of gamma. In addition, the interaction of this cavity mode with the beam charge varies as the inverse of the interaction with the magnetic moment, so that the background due to the beam charge varies as the inverse fourth power of gamma, If these gamma dependencies of moment and charge interaction with the pickup cavity do in fact exists the possibility is opened for very fast, accurate, and inexpensive polarimetry at accelerators like MIT-Bates and RHIC. In addition, it might become possible to seriously consider Stern-Gerlach polarization of beams at LHC. We present details of a quick polarimeter test at the electron storage ring at MIT-Bates, and of an extension of this test to a working polarimeter in the RHIC rings.

  19. Coal liquefaction to increase jet fuel production

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Processing concept that increases supply of jet fuel has been developed as part of study on methods for converting coal to hydrogen, methane, and jet fuel. Concept takes advantage of high aromatic content of coal-derived liquids to make high-octane gasoline, instead of destroying aromatics to make jet fuel.

  20. Imaging Stokes polarimeter by dual rotating retarder and analyzer and its application of evaluation of Japanese lacquer

    NASA Astrophysics Data System (ADS)

    Mizutani, Ryota; Ishikawa, Tomoharu; Ayama, Miyoshi; Otani, Yukitoshi

    2012-11-01

    Lacquer crafts are distributed over Southeast Asia from the East Asia such as China and Korea, Vietnam, Myanmar including Japan. Especially, a Japanese lacquer is well-known traditional crafts. Its color is jet black but people feel different texture because it is made by complicated and multi step manufacturing process such as coating and polishing with different materials. In this report, we focus polarization properties of surface structures on black Japanese lacquer. All states of polarization can be expressed Stokes parameters, which are consisted on four elements as s0 to s3. These parameters are effective for the evaluation of the state of polarization. The polarization information of surface structure of Japanese lacquer can be visualized by using an imaging Stokes polarimeter by dual rotating retarder and analyzer. It is possible to evaluate surface character by comparing the degree of polarization. It is effective to evaluate the surface by using the polarization information.

  1. 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

  2. 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.

  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 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…

  5. 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…

  6. Solid evacuated microspheres of hydrogen

    DOEpatents

    Turnbull, Robert J.; Foster, Christopher A.; Hendricks, Charles D.

    1982-01-01

    A method is provided for producing solid, evacuated microspheres comprised of hydrogen. The spheres are produced by forming a jet of liquid hydrogen and exciting mechanical waves on the jet of appropriate frequency so that the jet breaks up into drops with a bubble formed in each drop by cavitation. The drops are exposed to a pressure less than the vapor pressure of the liquid hydrogen so that the bubble which is formed within each drop expands. The drops which contain bubbles are exposed to an environment having a pressure just below the triple point of liquid hydrogen and they thereby freeze giving solid, evacuated spheres of hydrogen.

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

    PubMed

    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. PMID:26720051

  8. 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.

  9. PolKa: a polarimeter for submillimeter bolometer arrays

    NASA Astrophysics Data System (ADS)

    Siringo, Giorgio

    2003-04-01

    Starting from measurements of the linear polarization of the radiation emitted by celestial objects it is possible to estimate some physical parameters of the source. For example, magnetic field intensities and directions or, when the magnetic field is already known, the processes producing the polarization. A new concept of polarimeter has been designed to be used together with the arrays of bolometers developed in the Bolometer Group at the Max-Planck-Institut fuer Radioastronomie in Bonn. The new polarimeter has the unique characteristic of being tunable over a wide range of wavelengths and of producing a negligible absorption. It has been used at the Heinrich Hertz telescope in Arizona, to measure the linear polarization of some quasars and of some extended sources inside our galaxy. Some results are presented. We detected polarization on the quasars 3C279 and 1633+382. On 3C279 we also detected polarization variability on a time scale of a week. Three maps of extended sources are presented: the BN/KL complex in Orion OMC-1, a filament cloud in Orion OMC-3 and the massive star forming region IRAS 05358+3543. The first map shows the polarization pattern in OMC-1 over an extended sky area with high signal-to-noise and accurate detection of the position angle. The filament in OMC-3 was observed for a short integration time and is presented here only to show the agreement with published data even under conditions of a weak signal-to-noise. The third map is the first detection of polarization in the high-mass star forming region IRAS 05358+3543. The polarimeter has low spurious polarization and a good efficiency and the tests at the telescope show that it is well suited to become a permanent facility.

  10. Mitigation of image artifacts in LWIR microgrid polarimeter images

    NASA Astrophysics Data System (ADS)

    Ratliff, Bradley M.; Tyo, J. Scott; Boger, James K.; Black, Wiley T.; Bowers, David M.; Kumar, Rakesh

    2007-09-01

    Microgrid polarimeters, also known as division of focal plane (DoFP) polarimeters, are composed of an integrated array of micropolarizing elements that immediately precedes the FPA. The result of the DoFP device is that neighboring pixels sense different polarization states. The measurements made at each pixel can be combined to estimate the Stokes vector at every reconstruction point in a scene. DoFP devices have the advantage that they are mechanically rugged and inherently optically aligned. However, they suffer from the severe disadvantage that the neighboring pixels that make up the Stokes vector estimates have different instantaneous fields of view (IFOV). This IFOV error leads to spatial differencing that causes false polarization signatures, especially in regions of the image where the scene changes rapidly in space. Furthermore, when the polarimeter is operating in the LWIR, the FPA has inherent response problems such as nonuniformity and dead pixels that make the false polarization problem that much worse. In this paper, we present methods that use spatial information from the scene to mitigate two of the biggest problems that confront DoFP devices. The first is a polarimetric dead pixel replacement (DPR) scheme, and the second is a reconstruction method that chooses the most appropriate polarimetric interpolation scheme for each particular pixel in the image based on the scene properties. We have found that these two methods can greatly improve both the visual appearance of polarization products as well as the accuracy of the polarization estimates, and can be implemented with minimal computational cost.

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

    PubMed

    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 Seff (2)IIo 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. PMID:27250409

  12. 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.

  13. 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.

  14. RINGO2: an EMCCD-based polarimeter for GRB followup

    NASA Astrophysics Data System (ADS)

    Steele, I. A.; Bates, S. D.; Guidorzi, C.; Mottram, C. J.; Mundell, C. G.; Smith, R. J.

    2010-07-01

    We describe the design and construction of a new novel optical polarimeter (RINGO2) for the Liverpool Telescope. The instrument is designed for rapid (< 3 minute) followup observations of Gamma Ray Bursts in order to measure the early time polarization and time evolution on timescales of ~ 1 - 10000 seconds. By using a fast rotating Polaroid whose rotation is synchronized to control the readout of an electron multiplying CCD eight times per revolution, we can rebin our data in the time domain after acquisition with little noise penalty, thereby allowing us to explore the polarization evolution of these rapidly variable objects for the first time.

  15. Adapting a compact Mott spin polarimeter to a large commercial electron energy analyzer for spin-polarized electron spectroscopy

    NASA Astrophysics Data System (ADS)

    Huang, Di-Jing; Lee, Jae-Yong; Suen, Jih-Shih; Mulhollan, G. A.; Andrews, A. B.; Erskine, J. L.

    1993-12-01

    A modified Rice University-type compact Mott spin polarimeter operating at 20 kV is adapted to a large commerical hemispherical electron energy analyzer. Normal energy analyzer functions are preserved via a retractable channeltron in the polarimeter acceleration column. In the spin-detection mode, the polarimeter permits analysis of two orthogonal transverse spin-polarization components. Electron trajectory analysis is used to optimize polarimeter lens column voltages in both normal and spin-detection modes. Performance levels are established by experiments and significantly improved spin-detection efficiency is shown to be accessible by changes in the polarimeter collection solid angle.

  16. ATOMIC BEAM POLARIZATION MEASUREMENT OF THE RHIC POLARIZED H-JET TARGET.

    SciTech Connect

    MAKDISI,Y.; NASS,A.; GRAHAM,D.; KPONOU,A.; MAHLER,G.; MENG,W.; RITTER,J.; ET AL.

    2005-01-28

    The RHIC polarized H-Jet measures the polarization of the RHIC proton beam via elastic scattering off a nuclear polarized atomic hydrogen beam. The atomic beam is produced by a dissociator, a beam forming system and sextupole magnets. Nuclear polarization is achieved by exchanging occupation numbers of hyperfine states using high frequency transitions. The polarization was measured using a modified form of a Breit-Rabi polarimeter including focusing magnets and another set of high frequency transitions. The sampling of a large part of the beam and low noise electronics made it possible to measure the polarization to a high degree of accuracy in a very short time period (1 min). Using this system, we measured no depolarization of the atomic beam due to the RF fields of the bunched proton beam. Time-of-Flight measurements were done using a fast chopper and a QMA at the position of the RHIC interaction point to determine the areal density of the atomic beam seen by the RHIC beam.

  17. Fuzzy jets

    DOE PAGESBeta

    Mackey, Lester; Nachman, Benjamin; Schwartzman, Ariel; Stansbury, Conrad

    2016-06-01

    Here, collimated streams of particles produced in high energy physics experiments are organized using clustering algorithms to form jets . To construct jets, the experimental collaborations based at the Large Hadron Collider (LHC) primarily use agglomerative hierarchical clustering schemes known as sequential recombination. We propose a new class of algorithms for clustering jets that use infrared and collinear safe mixture models. These new algorithms, known as fuzzy jets , are clustered using maximum likelihood techniques and can dynamically determine various properties of jets like their size. We show that the fuzzy jet size adds additional information to conventional jet taggingmore » variables in boosted topologies. Furthermore, we study the impact of pileup and show that with some slight modifications to the algorithm, fuzzy jets can be stable up to high pileup interaction multiplicities.« less

  18. Fuzzy jets

    NASA Astrophysics Data System (ADS)

    Mackey, Lester; Nachman, Benjamin; Schwartzman, Ariel; Stansbury, Conrad

    2016-06-01

    Collimated streams of particles produced in high energy physics experiments are organized using clustering algorithms to form jets. To construct jets, the experimental collaborations based at the Large Hadron Collider (LHC) primarily use agglomerative hierarchical clustering schemes known as sequential recombination. We propose a new class of algorithms for clustering jets that use infrared and collinear safe mixture models. These new algorithms, known as fuzzy jets, are clustered using maximum likelihood techniques and can dynamically determine various properties of jets like their size. We show that the fuzzy jet size adds additional information to conventional jet tagging variables in boosted topologies. Furthermore, we study the impact of pileup and show that with some slight modifications to the algorithm, fuzzy jets can be stable up to high pileup interaction multiplicities.

  19. The Detector System for the Stratospheric Kinetic Inductance Polarimeter ( Skip)

    NASA Astrophysics Data System (ADS)

    Johnson, B. R.; Ade, P. A. R.; Araujo, D.; Bradford, K. J.; Chapman, D.; Day, P. K.; Didier, J.; Doyle, S.; Eriksen, H. K.; Flanigan, D.; Groppi, C.; Hillbrand, S.; Jones, G.; Limon, M.; Mauskopf, P.; McCarrick, H.; Miller, A.; Mroczkowski, T.; Reichborn-Kjennerud, B.; Smiley, B.; Sobrin, J.; Wehus, I. K.; Zmuidzinas, J.

    2014-09-01

    The stratospheric kinetic inductance polarimeter is a proposed balloon-borne experiment designed to study the cosmic microwave background, the cosmic infrared background and Galactic dust emission by observing 1,133 deg of sky in the Northern Hemisphere with launches from Kiruna, Sweden. The instrument contains 2,317 single-polarization, horn-coupled, aluminum lumped-element kinetic inductance detectors ( Lekids). The Lekids will be maintained at 100 mK with an adiabatic demagnetization refrigerator. The polarimeter operates in two configurations, one sensitive to a spectral band centered on 150 GHz and the other sensitive to 260 and 350 GHz bands. The detector readout system is based on the ROACH-1 board, and the detectors will be biased below 300 MHz. The detector array is fed by an F/2.4 crossed-Dragone telescope with a 500 mm aperture yielding a 15 arcmin FWHM beam at 150 GHz. To minimize detector loading and maximize sensitivity, the entire optical system will be cooled to 1 K. Linearly polarized sky signals will be modulated with a metal-mesh half-wave plate that is mounted at the telescope aperture and rotated by a superconducting magnetic bearing. The observation program consists of at least two, 5-day flights beginning with the 150 GHz observations.

  20. GRAPE: a balloon-borne gamma-ray polarimeter

    NASA Astrophysics Data System (ADS)

    McConnell, Mark L.; Bancroft, Christopher; Bloser, Peter F.; Connor, Taylor; Legere, Jason; Ryan, James M.

    2009-08-01

    The Gamma-RAy Polarimeter Experiment (GRAPE) is a concept for an astronomical hard X-ray Compton polarimeter operating in the 50 - 500 keV energy band. The instrument has been optimized for wide-field polarization measurements of transient outbursts from energetic astrophysical objects such as gamma-ray bursts and solar flares. The GRAPE instrument is composed of identical modules, each of which consists of an array of scintillator elements read out by a multi-anode photomultiplier tube (MAPMT). Incident photons Compton scatter in plastic scintillator elements and are subsequently absorbed in inorganic scintillator elements; a net polarization signal is revealed by a characteristic asymmetry in the azimuthal scattering angles. We have constructed a prototype GRAPE module that has been calibrated at a polarized hard X-ray beam and flown on an engineering balloon test flight. A full-scale scientific balloon payload, consisting of up to 36 modules, is currently under development. The first flight, a one-day flight scheduled for 2011, will verify the expected scientific performance with a pointed observation of the Crab Nebula. We will then propose long-duration balloon flights to observe gamma-ray bursts and solar flares.

  1. Polarization visual enhancement technique for LWIR microgrid polarimeter imagery

    NASA Astrophysics Data System (ADS)

    Ratliff, Bradley M.; Tyo, J. Scott; Black, Wiley T.; Boger, James K.; Bowers, David L.

    2008-04-01

    Division of focal plane (DoFP) polarimeters are a particular class of imaging device that consists of an array of micropolarizers integrated upon a focal plane array sensor (FPA). Such devices are also called microgrid polarimeters and have been studied over the past decade with systems being designed and built in all regions of the optical spectrum. These systems are advantageous due to their rugged, compact design and ability to obtain a complete set of polarimetric measurements during a single frame capture. One inherent disadvantage of DoFP systems is that each pixel of the FPA sensor makes a polarized intensity measurement of a different scene point. These spatial measurements are then used to estimate the Stokes vectors across the scene. Since each polarized intensity measurement has a different instantaneous field-of-view (IFOV), artifacts are introduced that can degrade the quality of estimated polarization imagery. Here we develop and demonstrate a visual enhancement technique that is able to reduce false polarization caused by IFOV error while preserving true polarization content within the Stokes parameter images. The technique is straight-forward conceptually and is computationally efficient. All results are presented using data acquired from an actual LWIR microgrid sensor.

  2. Exploiting motion-based redundancy to enhance microgrid polarimeter imagery

    NASA Astrophysics Data System (ADS)

    Ratliff, Bradley M.; Tyo, J. Scott; Black, Wiley T.; LaCasse, Charles F.

    2009-08-01

    Microgrid polarimeters are a type of division of focal plane (DoFP) imaging polarimeter that contains a mosaic of pixel-wise micropolarizing elements superimposed upon an FPA sensor. Such a device measures a slightly different polarized state at each pixel. These measurements are combined to estimate the Stokes vector at each pixel in the image. DoFP devices have the advantage that they can obtain Stokes vector image estimates for an entire scene from a single frame capture. However, they suffer from the disadvantage that the neighboring measurements that are used to estimate the Stokes vector images are acquired at differing instantaneous fields of view (IFOV). This IFOV issue leads to false polarization signatures that significantly degrade the Stokes vector images. Interpolation and other image processing strategies can be employed to reduce IFOV artifacts; however these techniques have a limit to the amount of enhancement they can provide on a single microgrid image. Here we investigate algorithms that use multiple microgrid images that contain frame-to-frame global motion to further enhance the Stokes vector image estimates. Motion-based imagery provides additional redundancy that can be exploited to recover information that is "missing" from a single microgrid frame capture. We have found that IFOV and aliasing artifacts can be defeated entirely when these types of algorithms are applied to the data prior to Stokes vector estimation. We demonstrate results on real LWIR microgrid data using a particular resolution enhancement technique from the literature.

  3. 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.

  4. 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.

  5. 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

  6. Unique electron polarimeter analyzing power comparison and precision spin-based energy measurement

    SciTech Connect

    Joseph Grames; Charles Sinclair; Joseph Mitchell; Eugene Chudakov; Howard Fenker; Arne Freyberger; Douglas Higinbotham; B. Poelker; Michael Steigerwald; Michael Tiefenback; Christian Cavata; Stephanie Escoffier; Frederic Marie; Thierry Pussieux; Pascal Vernin; Samuel Danagoulian; Kahanawita Dharmawardane; Renee Fatemi; Kyungseon Joo; Markus Zeier; Viktor Gorbenko; Rakhsha Nasseripour; Brian Raue; Riad Suleiman; Benedikt Zihlmann

    2004-03-01

    Precision measurements of the relative analyzing powers of five electron beam polarimeters, based on Compton, Moller, and Mott scattering, have been performed using the CEBAF accelerator at the Thomas Jefferson National Accelerator Facility (Jefferson Laboratory). A Wien filter in the 100 keV beamline of the injector was used to vary the electron spin orientation exiting the injector. High statistical precision measurements of the scattering asymmetry as a function of the spin orientation were made with each polarimeter. Since each polarimeter receives beam with the same magnitude of polarization, these asymmetry measurements permit a high statistical precision comparison of the relative analyzing powers of the five polarimeters. This is the first time a precise comparison of the analyzing powers of Compton, Moller, and Mott scattering polarimeters has been made. Statistically significant disagreements among the values of the beam polarization calculated from the asymmetry measurements made with each polarimeter reveal either errors in the values of the analyzing power, or failure to correctly include all systematic effects. The measurements reported here represent a first step toward understanding the systematic effects of these electron polarimeters. Such studies are necessary to realize high absolute accuracy (ca. 1%) electron polarization measurements, as required for some parity violation measurements planned at Jefferson Laboratory. Finally, a comparison of the value of the spin orientation exiting the injector that provides maximum longitudinal polarization in each experimental hall leads to an independent and very precise (better than 10-4) absolute measurement of the final electron beam energy.

  7. A closed-loop dual-modulation multi-spectral polarimeter for glucose monitoring

    NASA Astrophysics Data System (ADS)

    Yu, Zhen fang; Pirnstill, Casey W.; Coté, Gerard L.

    2016-03-01

    Optical polarimetry is a promising noninvasive means of assessing glucose concentration in the aqueous humor of the eye. One the major limiting factors is time-varying cornea birefringence due to motion artifact, which prevents the realization of this device. In this study, we simultaneously utilize laser intensity modulation and Faraday polarization rotation modulation for a real-time closed-loop multi-spectral polarimeter for glucose monitoring in vitro. In this report, a real-time closed-loop dual-modulation dual-spectral polarimeter was presented and in vitro glucose measurements were performed demonstrating the accuracy and repeatability of this polarimeter.

  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. Opposed jet burner studies of effects of CO, CO2, and N2 air-contaminants on hydrogen-air diffusion flames

    NASA Technical Reports Server (NTRS)

    Guerra, Rosemary; Pellett, Gerald L.; Northam, G. Burton; Wilson, Lloyd G.

    1987-01-01

    The blowoff/restore characteristics for jets of various H2/N2 mixtures opposed to jets of air contaminated by N2, CO, and CO2 have been determined using a counterflow diffusion flame formed by a tubular opposed jet burner. Both blowoff and restore limits are found to be sensitive to fuel and air composition. Empirically derived variations in the limits of the average mass flux of incoming H2 with percent contaminant, at fixed incoming fuel and H2/O2 inputs, are used to quantify the effects of oxygen dilution, flame augmentation, and flame retardation by N2, CO, and CO2 contaminants. The implications of the results are discussed.

  10. Matrix structure for information-driven polarimeter design

    NASA Astrophysics Data System (ADS)

    Alenin, Andrey S.

    Estimating the polarization of light has been shown to have merit in a wide variety of applications between UV and LWIR wavelengths. These tasks include target identification, estimation of atmospheric aerosol properties, biomedical and other applications. In all of these applications, polarization sensing has been shown to assist in discrimination ability; however, due to the nature of many phenomena, it is difficult to add polarization sensing everywhere. The goal of this dissertation is to decrease the associated penalties of using polarimetry, and thereby broaden its applicability to other areas. First, the class of channeled polarimeter systems is generalized to relate the Fourier domains of applied modulations to the resulting information channels. The quality of reconstruction is maximized by virtue of using linear system manipulations rather than arithmetic derived by hand, while revealing system properties that allow for immediate performance estimation. Besides identifying optimal systems in terms of equally weighted variance (EWV), a way to redistribute the error between all the information channels is presented. The result of this development often leads to superficial changes that can improve signal-to-noise-ration (SNR) by up to a factor of three compared to existing designs in the literature. Second, the class of partial Mueller maitrx polarimeters (pMMPs) is inspected in regards to their capacity to match the level of discrimination performance achieved by full systems. The concepts of structured decomposition and the reconstructables matrix are developed to provide insight into Mueller subspace coverage of pMMPs, while yielding a pMMP basis that allows the formation of ten classes of pMMP systems. A method for evaluating such systems while considering a multi-objective optimization of noise resilience and space coverage is provided. An example is presented for which the number of measurements was reduced to half. Third, the novel developments

  11. Cosmic jets

    SciTech Connect

    Blandford, R.D.; Begelman, M.C.; Rees, M.J.

    1982-05-01

    Observations with radio telescopes have revealed that the center of many galaxies is a place of violent activity. This activity is often manifested in the production of cosmic jets. Each jet is a narrow stream of plasma that appears to squirt out of the center of a galaxy emitting radiowaves as it does so. New techniques in radio astronomy have shown how common jets are in the universe. These jets take on many different forms. The discovery of radio jets has helped in the understanding of the double structure of the majority of extragalactic radio sources. The morphology of some jets and explanations of how jets are fueled are discussed. There are many difficulties plaguing the investigation of jets. Some of these difficulties are (1) it is not known how much power the jets are radiating, (2) it is hard to tell whether a jet delieated by radio emission is identical to the region where ionized gas is flowing, and (3) what makes them. (SC)

  12. Radar cross calibration investigation TAMU radar polarimeter calibration measurements

    NASA Astrophysics Data System (ADS)

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

    1982-10-01

    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.

  13. 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

  14. 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.

  15. Cyclops: a single beam 1.3 millimeter polarimeter.

    NASA Astrophysics Data System (ADS)

    Glenn, J.; Walker, C. K.; Young, E. T.

    1997-02-01

    The authors present the design of a broadband, 1.3 mm polarimeter for astronomical observations and the results of first light observations at the Heinrich Hertz Telescope (HHT). The systematic polarization of the instrument plus telescope is 1.1%. The observed linear polarization of DR21, P = 1.65%±0.14% and θ = 16°±2°, is consistent with previous measurements. The authors' 0.9% upper limit on the linear polarization of Cepheus A is the first 1.3 mm measurement reported. With Cyclops it is possible to map the magnetic fields in several of the brightest molecular cloud dust cores in the Milky Way. The authors comment on the expected performance of an achromatic Rexolite half-waveplate for λ = 800 μm to 1.3 mm.

  16. 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.

  17. Radar polarimeter measures orientation of calibration corner reflectors

    NASA Technical Reports Server (NTRS)

    Zebker, Howard A.; Norikane, Lynne

    1987-01-01

    Radar polarimeter signals from a set of trihedral corner reflectors located in the Goldstone Dry Lake in California were analyzed, and three types of scattering behavior were observed: (1) Bragg-like slightly rough surface scattering that represents the background signal from the dry lake, (2) trihedral corner reflector scattering that returns the incident polarization, and (3) two-bounce corner reflector scattering resulting from a particular alignment of a trihedral reflector. A radar calibration approach using trihedral corner reflectors should be designed such that precise alignment of the reflectors is ensured, as three-bounce and two-bounce geometries lead to very different cross sections and hence very different inferred calibration factors.

  18. Development and characterization analysis of a radar polarimeter

    NASA Technical Reports Server (NTRS)

    Bong, S.; Blanchard, A. J.

    1983-01-01

    The interaction of electromagnetic waves with natural earth surface was of interest for many years. A particular area of interest in controlled remote sensing experiments is the phenomena of depolarization. The development stages of the radar system are documented. Also included are the laboratory procedures which provides some information about the specifications of the system. The radar system developed is termed the Radar Polarimeter System. A better insight of the operation of the RPS in terms of the newly developed technique--synthetic aperture radar system is provided. System performance in tems of radar cross section, in terms of power, and in terms of signal to noise ratio are also provided. In summary, an overview of the RPS in terms of its operation and design as well as how it will perform in the field is provided.

  19. 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.

  20. 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.

  1. Real-time sub-pixel registration of imagery for an IR polarimeter

    NASA Astrophysics Data System (ADS)

    Hanks, Jonathan B.; Pezzaniti, J. Larry; Chenault, David B.; Romano, João M.

    2012-06-01

    In imaging polarimetry, special consideration must be given to ensure proper spatial registration between frames. Edge artifacts caused by the differencing of unregistered frames has the potential to create significant spurious polarization signatures. To achieve 1/10th pixel registration or better, a software based registration approach is often required. The focus of this paper is to present an efficient algorithm for real time sub-pixel registration in a division-of-time IR polarimeter based on a rotating polarizer. This algorithm has been implemented in a commercially available rotating polarizer LWIR imaging polarimeter offered by Polaris Sensor Technologies. This paper presents measurements of image nutation in a rotating polarizer LWIR imaging polarimeter and real-time registration of image data from that same polarimeter. The registration algorithm is based on an optimal 2D convolution. Examples of registered images are provided as well as estimates of residual misregistration artifacts.

  2. Digital panoramic polarimeter for remote investigatirn of an optical parameter of celestial bodies

    NASA Astrophysics Data System (ADS)

    Vidmachenko, A. P.; Delec, A. S.; Nevodovskiy, PV.; Andruk, V. M.

    2003-09-01

    Digital panoramic polarimeter is an astronomical television device with panoramic high-sensitivity receiver "superisokone", LI-804 and mechanical block which consist of the polaroid modulator and large rotating achromatic phase-shift plate.

  3. Motion-based nonuniformity correction in DoFP polarimeters

    NASA Astrophysics Data System (ADS)

    Kumar, Rakesh; Tyo, J. Scott; Ratliff, Bradley M.

    2007-09-01

    Division of Focal Plane polarimeters (DoFP) operate by integrating an array of micropolarizer elements with a focal plane array. These devices have been investigated for over a decade, and example systems have been built in all regions of the optical spectrum. DoFP devices have the distinct advantage that they are mechanically rugged, inherently temporally synchronized, and optically aligned. They have the concomitant disadvantage that each pixel in the FPA has a different instantaneous field of view (IFOV), meaning that the polarization component measurements that go into estimating the Stokes vector across the image come from four different points in the field. In addition to IFOV errors, microgrid camera systems operating in the LWIR have the additional problem that FPA nonuniformity (NU) noise can be quite severe. The spatial differencing nature of a DoFP system exacerbates the residual NU noise that is remaining after calibration, and is often the largest source of false polarization signatures away from regions where IFOV error dominates. We have recently presented a scene based algorithm that uses frame-to-frame motion to compensate for NU noise in unpolarized IR imagers. In this paper, we have extended that algorithm so that it can be used to compensate for NU noise on a DoFP polarimeter. Furthermore, the additional information provided by the scene motion can be used to significantly reduce the IFOV error. We have found a reduction of IFOV error by a factor of 10 if the scene motion is known exactly. Performance is reduced when the motion must be estimated from the scene, but still shows a marked improvement over static DoFP images.

  4. The Hertz-VPM polarimeter and applications of multiwavelength polarimetry

    NASA Astrophysics Data System (ADS)

    Krejny, Megan M.

    We present initial results from 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 (HWP). 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 that properties of the VPM wire grids (diameter and spacing) caused behavior that differs from theoretical predictions for ideal wire grid performance. Modifying the polarimeter settings to compensate for this behavior, 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, and is also advantageous for multi-wavelength polarimetry applications. One such application concerns submillimeter spectropolarimetry of T Tauri Star (TTS) disks, to probe the grains in this environment. We present 350 mm polarimetry of the circumstellar disk of DG Tau. Comparison with a previous measurement made at 850 mm suggests that there is considerable structure in the submillimeter polarization spectrum. We also discuss theoretical models for polarized emission from TTS disks, both simple toy models developed at Northwestern and a more sophisticated model published more recently by J. Cho and A. Lazarian. The data do not agree with this more recent model, but it is plausible that this could be due to the larger mass of the DG Tau disk in comparison to the model disk.

  5. Water Jetting

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Hi-Tech Inc., a company which manufactures water jetting equipment, needed a high pressure rotating swivel, but found that available hardware for the system was unsatisfactory. They were assisted by Marshall, which had developed water jetting technology to clean the Space Shuttles. The result was a completely automatic water jetting system which cuts rock and granite and removes concrete. Labor costs have been reduced; dust is suppressed and production has been increased.

  6. Cosmic jets

    NASA Technical Reports Server (NTRS)

    Rees, M. J.

    1986-01-01

    The evidence that active galactic nuclei produce collimated plasma jets is summarised. The strongest radio galaxies are probably energised by relativistic plasma jets generated by spinning black holes interacting with magnetic fields attached to infalling matter. Such objects can produce e(+)-e(-) plasma, and may be relevant to the acceleration of the highest-energy cosmic ray primaries. Small-scale counterparts of the jet phenomenon within our own galaxy are briefly reviewed.

  7. 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.

  8. 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

  9. Analysis of AGS polarimeter data at G{gamma}=7.5.

    SciTech Connect

    Huang, H.; Cadman, R. V.; Spinka, H. M.; Underwood, D. G.

    2003-02-18

    Data were collected with the AGS internal polarimeter at G{gamma} = 7.5 during the recent FY02 polarized proton run. The addition of new forward scintillation counters permitted an absolute calibration of the polarimeter for both nylon and carbon targets. The results are summarized, and the polarization measured at G{gamma} = 7.5 is compared to that at 200 MeV.

  10. Unconditional jetting.

    PubMed

    Gañán-Calvo, Alfonso M

    2008-08-01

    Capillary jetting of a fluid dispersed into another immiscible phase is usually limited by a critical capillary number, a function of the Reynolds number and the fluid property ratios. Critical conditions are set when the minimum spreading velocity of small perturbations v_{-};{*} along the jet (marginal stability velocity) is zero. Here we identify and describe parametric regions of high technological relevance, where v_{-};{*}>0 and the jet flow is always supercritical independently of the dispersed liquid flow rate; within these relatively broad regions, the jet does not undergo the usual dripping-jetting transition, so that either the jet can be made arbitrarily thin (yielding droplets of any imaginably small size), or the issuing flow rate can be made arbitrarily small. In this work, we provide illustrative analytical studies of asymptotic cases for both negligible and dominant inertia forces. In this latter case, requiring a nonzero jet surface velocity, axisymmetric perturbation waves "surf" downstream for all given wave numbers, while the liquid bulk can remain static. In the former case (implying small Reynolds flow) we found that the jet profile small slope is limited by a critical value; different published experiments support our predictions. PMID:18850933

  11. 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.

  12. High resolution confocal polarimeter for the living human retina

    NASA Astrophysics Data System (ADS)

    Lara, D.; Paterson, C.

    2011-09-01

    There is strong evidence that the living human retina has polarization signatures that could be linked to the presence of Glaucoma, an ocular disease that is the second cause of blindness in the western world. In a polarization sensitive ophthalmoscope, the amount of light that can be used is limited for the safety of the subject, and the return is typically a small fraction of the light used for illumination, of the order of 10-6. Furthermore, the acquisition rates have to be sufficiently fast to avoid eye-movement artifacts. The light-budget available to produce a polarization image with a scanning laser ophthalmoscope is typically in the order of 10 nW, and pixel acquisition sampling rates are of several MHz. We are currently developing an imaging instrument for vision research and clinical vision applications and aim to introduce it to the medical and clinical environment using objective methods of image quality assessment. Here we discuss the stringent imaging requirements, polarimeter design, and show high resolution polarization retinal images.

  13. Bragg crystal polarimeter for the Spectrum-X-Gamma mission

    NASA Technical Reports Server (NTRS)

    Holley, J.; Silver, E.; Ziock, K. P.; Novick, R.; Kaaret, P.; Weisskopf, M.; Elsner, R.; Beeman, J.

    1991-01-01

    A Bragg crystal polarimeter for the focal plane of the SODART telescope on the Spectrum-X-Gamma mission is being designed. A mosaic graphite crystal will be oriented at 45 deg to the optic axis of the telescope, thereby preferentially reflecting those X-rays which satisfy the Bragg condition and have electric vectors that are perpendicular to the plane defined by the incident and reflected photons. The reflected X-rays will be detected by an imaging proportional counter with the image providing direct X-ray aspect information. The crystal will be about 50 microns thick to allow X-rays with energies of 4 keV or greater to be transmitted to a lithium block mounted below the graphite. The lithium is used to measure the polarization of these high energy X-rays by exploiting the polarization dependence of Thomson scattering. The development of thin mosaic graphite crystals is discussed and recent reflectivity, transmission, and uniformity measurements are presented.

  14. Bragg crystal polarimeter for the Spectrum-X-Gamma mission

    SciTech Connect

    Holley, J.; Silver, E.; Ziock, K.P. ); Novick, R.; Kaaret, P. . Columbia Astrophysics Lab.); Weisskopf, M.; Elsner, R. . George C. Marshall Space Flight Center); Beeman, J. )

    1990-08-13

    We are designing a Bragg crystal polarimeter for the focal plane of the SODART telescope on the Spectrum-X-Gamma mission. A mosaic graphite crystal will be oriented at 45{degree} to the optic axis of the telescope, thereby preferentially reflecting those x-rays which satisfy the Bragg condition and have electric vectors that are perpendicular to the plane defined by the incident and reflected photons. The reflected x-rays will be detected by an imaging proportional counter with the image providing direct x-ray aspect information. The crystal will be {approx}50 {mu}m thick to allow x-rays with energies {ge}4 keV to be transmitted to a lithium block mounted below the graphite. The lithium is used to measure the polarization of these high energy x-rays by exploiting the polarization dependence of Thomson scattering. The development of thin mosaic graphite crystals is discussed and recent reflectivity, transmission, and uniformity measurements are presented. 8 refs., 11 figs., 1 tab.

  15. Soft X-ray polarimeter-spectrometer SOLPEX

    NASA Astrophysics Data System (ADS)

    Steslicki, Marek; Sylwester, Janusz; Plocieniak, Stefan; Bakala, Jaroslaw; Szaforz, Zaneta Anna; Scislowski, Daniel; Kowalinski, Miroslaw; Hernandez, Jose; Vadimovich Kuzin, Sergey; Shestov, Sergey

    2015-08-01

    We present an innovative soft X-ray polarimeter and spectrometer SOLPEX. The instrument will be mounted aboard the ISS within the Russian science complex KORTES. The measurements to be made by SOLPEX are expected to be of unprecedented quality in terms of sensitivity to detect the soft-X- ray polarization of solar emission emanating from active regions and flares in particular. Simultaneous measurements of the polarization degree and the other characteristics (eg. evolution of the spectra) constitute the last, rather unexplored area of solar X-ray spectroscopy providing substantial diagnostic potential. Second important science task to be addressed are the measurements of Doppler shifts in selected X-ray spectral emission lines formed in hot flaring sources. The novel-type Dopplerometer (flat Bragg crystal drum unit) is planned to be a part of SOLPEX and will allow to measure line Doppler shifts in absolute terms with unprecedented time resolution (fraction of a second) during the impulsive flare phases. We shall present some details of the SolpeX instrument and discuss observing sequences in a view of science objectives to be reached.

  16. 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.

  17. A circular polarimeter for the Cosmic Microwave Background

    SciTech Connect

    Giovannini, Massimo

    2010-08-01

    A primordial degree of circular polarization of the Cosmic Microwave Background is not observationally excluded. The hypothesis of primordial dichroism can be quantitatively falsified if the plasma is magnetized prior to photon decoupling since the initial V-mode polarization affects the evolution of the temperature fluctuations as well as the equations for the linear polarization. The observed values of the temperature and polarization angular power spectra are used to infer constraints on the amplitude and on the spectral slope of the primordial V-mode. Prior to photon decoupling magnetic fields play the role of polarimeters insofar as they unveil the circular dichroism by coupling the V-mode power spectrum to the remaining brightness perturbations. Conversely, for angular scales ranging between 4 deg and 10 deg the joined bounds on the magnitude of circular polarization and on the magnetic field intensity suggest that direct limits on the V-mode power spectrum in the range of 0.01 mK could directly rule out pre-decoupling magnetic fields in the range of 10–100 nG. The frequency dependence of the signal is located, for the present purposes, in the GHz range.

  18. Alignment error analysis of the snapshot imaging polarimeter.

    PubMed

    Liu, Zhen; Yang, Wei-Feng; Ye, Qing-Hao; Hong, Jin; Gong, Guan-Yuan; Zheng, Xiao-Bing

    2016-03-10

    A snapshot imaging polarimeter (SIP) system is able to reconstruct two-dimensional spatial polarization information through a single interferogram. In this system, the alignment errors of the half-wave plate (HWP) and the analyzer have a predominant impact on the accuracies of reconstructed complete Stokes parameters. A theoretical model for analyzing the alignment errors in the SIP system is presented in this paper. Based on this model, the accuracy of the reconstructed Stokes parameters has been evaluated by using different incident states of polarization. An optimum thickness of the Savart plate for alleviating the perturbation introduced by the alignment error of the HWP is found by using the condition number of the system measurement matrix as an objective function in a minimization procedure. The result shows that when the thickness of a Savart plate is 23 mm, corresponding to the condition number 2.06, the precision of the SIP system can reach to 0.21% at 1° alignment tolerance of the HWP. PMID:26974785

  19. A polarimeter for measurement of transient retardation changes.

    PubMed

    Johnston, A R

    1969-09-01

    An electronic polarimeter is described in which a signal-sampling technique and feedback are used together to measure periodic retardation changes. A Faraday cell is arranged to feed back a rotation just sufficient to cancel that caused by the unknown retardation, so that the Faraday cell current provides the quantitative measure desired. The photomultiplier output is fed to a sampling oscilloscope in the feedback loop. The instrument is best suited for the measurement of small retardation changes, of the order of 50 mrad or less. The 6-nsec time resolution obtained was limited by the photomultiplier response; a faster detector could improve it considerably. The repeatability obtained of 10(-4) rad was determined by the usual compromise between noise, primarily photon noise, and averaging time. However, other factors limit the accuracy attainable to, at best, +/-3%, for a retardation change of ~20 mrad, while a more typical accuracy was +/-5%. Either Faraday rotation, or small rotations of the optical ellipsoid of aspecimen, could also be observed. PMID:20072532

  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. Preliminary evaluation of the air and fuel specific-impulse characteristics of several potential ram-jet fuels IV : hydrogen, a-methylnaphthalene, and carbon / Benson E. Gammon

    NASA Technical Reports Server (NTRS)

    Gammon, Benson E

    1951-01-01

    A preliminary analytical evaluation of the air and fuel specific-impulse characteristics of hydrogen, a-methylnapthalene, and graphite carbon has been made. Adiabatic constant-pressure combustion flame temperatures for each fuel at several equivalence ratios were calculated for an initial air temperature of 560 degrees R and a pressure of 2 atmospheres.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  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. PMID:17086251

  9. Emerging jets

    NASA Astrophysics Data System (ADS)

    Schwaller, Pedro; Stolarski, Daniel; Weiler, Andreas

    2015-05-01

    In this work, we propose a novel search strategy for new physics at the LHC that utilizes calorimeter jets that (i) are composed dominantly of displaced tracks and (ii) have many different vertices within the jet cone. Such emerging jet signatures are smoking guns for models with a composite dark sector where a parton shower in the dark sector is followed by displaced decays of dark pions back to SM jets. No current LHC searches are sensitive to this type of phenomenology. We perform a detailed simulation for a benchmark signal with two regular and two emerging jets, and present and implement strategies to suppress QCD backgrounds by up to six orders of magnitude. At the 14 TeV LHC, this signature can be probed with mediator masses as large as 1.5 TeV for a range of dark pion lifetimes, and the reach is increased further at the high-luminosity LHC. The emerging jet search is also sensitive to a broad class of long-lived phenomena, and we show this for a supersymmetric model with R-parity violation. Possibilities for discovery at LHCb are also discussed.

  10. The Galway astronomical Stokes polarimeter: an all-Stokes optical polarimeter with ultra-high time resolution

    NASA Astrophysics Data System (ADS)

    Collins, Patrick; Kyne, Gillian; Lara, David; Redfern, Michael; Shearer, Andy; Sheehan, Brendan

    2013-12-01

    Many astronomical objects emit polarised light, which can give information both about their source mechanisms, and about (scattering) geometry in their source regions. To date (mostly) only the linearly polarised components of the emission have been observed in stellar sources. Observations have been constrained because of instrumental considerations to periods of excellent observing conditions, and to steady, slowly or periodically-varying sources. This leaves a whole range of interesting objects beyond the range of observation at present. The Galway Astronomical Stokes Polarimeter (GASP) has been developed to enable us to make observations on these very sources. GASP measures the four components of the Stokes Vector simultaneously over a broad wavelength range 400-800 nm., with a time resolution of order microseconds given suitable detectors and a bright source - this is possible because the optical design contains no moving or modulating components. The initial design of GASP is presented and we include some preliminary observational results demonstrating that components of the Stokes vector can be measured to % in conditions of poor atmospheric stability. Issues of efficiency and stability are addressed. An analysis of suitable astronomical targets, demanding the unique properties of GASP, is also presented.

  11. The RHIC p-Carbon CNI Polarimeter Upgrade For The Beam Polarization And Intensity Measurements

    SciTech Connect

    Zelenski, A.; Bazilevski, A.; Bunce, G.; Gill, R.; Huang, H.; Mahler, G.; Makdisi, Y.; Morozov, B.; Nemesure, S.; Russo, T.; Steski, D.; Sivertz, M.

    2009-08-04

    Proton polarization measurements in the AGS and RHIC (Relativistic Heavy Ion Collider at the beam energies 24-250 GeV) are based on proton-carbon and proton-proton elastic scattering in the Coulomb Nuclear Interference (CNI) region. Polarimeter operation in the scanning mode also gives polarization profile and beam intensity profile (beam emittance) measurements. Bunch by bunch emittance measurement is a very powerful tool for machine setup. Presently, the polarization and beam intensity profile measurements (in both vertical and horizontal planes) are restricted by the long target switching time and possible target destruction during this complicated motion. The RHIC polarimeters were operated near the limit of the counting rate for present silicon strip detectors. The ongoing polarimeter upgrade for the 2009 run will address all these problems. The upgrade should allow significant reduction of the polarization measurement errors by making feasible the complete polarization measurements, which includes polarization profiles in both the horizontal and vertical planes.

  12. Design of a celestial Thomson-scattering X-ray polarimeter.

    NASA Technical Reports Server (NTRS)

    Landecker, P. B.

    1972-01-01

    A general discussion of the scientific importance and status of stellar X-ray polarimetry is presented. A stellar X-ray polarimeter designed to fit into the bottom half of the NASA OSO-1 wheel compartment or other similar spacecraft is described. In this design, the linear polarization is obtained as a function of energy. The sensitivity of the polarimeter in the 4-24 keV energy range was optimized with the aid of a Monte Carlo simulation computer program and is given for several important celestial X-ray sources. Estimates of sensitivity thresholds for a much larger polarimeter, suitable for flight in the NASA High-Energy Astronomy Observatory (HEAO), are also given. The minimum detectable polarization for several X-ray sources is given.

  13. A high sensitivity polarimeter for the direct detection and characterization of extra-solar planets

    NASA Astrophysics Data System (ADS)

    Hough, James H.; Lucas, Philip W.; Bailey, Jeremy A.; Tamura, Motohide

    2003-02-01

    We are constructing a high sensitivity optical polarimeter capable of detecting fractional polarization levels below 10-6. The science goal is to directly detect extra-solar planets (ESP), in contrast to the indirect methods such as radial velocity measurements. The polarimeter will detect starlight scattered from the atmosphere of the planet as a polarisation signal thereby giving information on the planetary atmospheres. The radius of the planet and the planet temperature can be determined from the measured albedo. The position angle of polarisation will enable the mass of planets, detected through radial velocity measurements, to be determined without the uncertainty of the orbit inclination (Msini). The polarimeter has an essentially simple and classical design but is able to take advantage, inter alia, of modern detector technology.

  14. 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.

  15. POLIX: A Thomson X-ray polarimeter for a small satellite mission

    NASA Astrophysics Data System (ADS)

    Paul, Biswajit; Gopala Krishna, M. R.; Puthiya Veetil, Rishin

    2016-07-01

    POLIX is a Thomson X-ray polarimeter for a small satellite mission of ISRO. The instrument consists of a collimator, a scatterer and a set proportional counters to detect the scattered X-rays. We will describe the design, specifications, sensitivity, and development status of this instrument and some of the important scientific goals. This instrument will provide unprecedented opportunity to measure X-ray polarisation in the medium energy range in a large number of sources of different classes with a minimum detectable linear polarisation degree of 2-3%. The prime objects for observation with this instrument are the X-ray bright accretion powered neutron stars, accreting black holes in different spectral states, rotation powered pulsars, magnetars, and active galactic nuclei. This instrument will be a bridge between the soft X-ray polarimeters and the Compton polarimeters.

  16. A 1.2--Millimeter Broad--Band Polarimeter

    NASA Astrophysics Data System (ADS)

    Glenn, Jason; Walker, Christopher K.; Young, Erick T.

    1996-05-01

    We describe a 1.2--millimeter polarimeter to be used on the Steward Observatory and Max--Planck--Institut fur Radioastronomie 10--meter Submillimeter Telescope Observatory. The construction, performance parameters, and scientific purpose of the instrument are presented. The detector is a Ge bolometer with a Si absorber operated in a cavity cooled to 0.36 K by a liquid He(3) refrigerator. The bandpass has a central wavelength of 1.2 mm and a width of 0.3 mm. The system noise equivalent power is 1.5*E(-14) W Hz(-{1/2}) at 20 Hz. Polarimetric modulation is accomplished with a room temperature, rotating Rexolite half-wave plate. Unidirectional grooves provide the lambda /2 phase shift between the orthogonal senses of polarization. The polarization analyzer is a stationary, room temperature, unidirectional wire grid that transmits only one sense of polarization with 99% efficiency. The system polarimetric efficiency is 87% and the laboratory instrumental polarization is a well defined 3.7%. Detection of a 1% linear polarization is possible at the several sigma level. The primary scientific goal of this instrument is to probe the magnetic field orientations in the protostellar dust cores of molecular clouds. Non--spherical dust grains are aligned in the presence of a magnetic field resulting in linear polarization of the far--infrared thermal dust emission perpendicular to the magnetic field vector. Observed field orientations will be compared to protostellar molecular outflow orientations and magnetic fields on larger scales. With these comparisons we will assess the role of magnetic fields in cloud collapse and star formation.

  17. 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.

  18. SPIDER: Probing the Early Universe with a Suborbital Polarimeter

    NASA Astrophysics Data System (ADS)

    Fraisse, Aurélien A.; SPIDER Collaboration

    2012-01-01

    SPIDER is a balloon-borne polarimeter designed to detect a divergence-free polarization pattern ("B-modes") in the Cosmic Microwave Background (CMB). In the inflationary scenario, the spectrum of the tensor perturbations that generate this signal is proportional to that of the primordial scalar perturbations through the tensor-to-scalar ratio r. The expected level of systematic error in the SPIDER instrument is significantly below the amplitude of an interesting cosmological B-mode signal with r=0.03. An optimized scanning strategy enables us to minimize uncertainty in the reconstruction of the Stokes parameters used to characterize the CMB, while providing access to a relatively wide range of angular scales. In the SPIDER field, the polarized emission from interstellar dust is as bright or brighter than the cosmological r=0.03 B-mode signal at all SPIDER frequencies (90, 150, and 280 GHz), a situation similar to that found in the "Southern Hole." Despite this foreground contamination, two 20-day flights of the SPIDER instrument will constrain the amplitude of the B-mode signal to r<0.03 (99% CL). In the absence of foregrounds, the same limit can be reached after one 20-day flight. The Spider collaboration gratefully acknowledges the support of NASA (APRA-NNX07AL64G), the National Science Foundation (ANT-1043515), the Gordon and Betty Moore Foundation, and the David and Lucile Packard Foundation. Support in Canada is provided by NSERC, the Canadian Space Agency, the Canada Foundation for Innovation, and CIFAR.

  19. Foreground-induced biases in CMB polarimeter self-calibration

    NASA Astrophysics Data System (ADS)

    Abitbol, Maximilian H.; Hill, James; Johnson, Bradley

    2016-06-01

    Precise polarization measurements of the cosmic microwave background (CMB) require accurate knowledge of the instrument orientation relative to the sky frame used to define the cosmological Stokes parameters. Suitable celestial calibration sources that could be used to measure the polarimeter orientation angle are limited, so current experiments commonly `self-calibrate.' The self-calibration method exploits the theoretical fact that the EB and TB cross-spectra of the CMB vanish in the standard cosmological model, so any detected EB and TB signals must be due to systematic errors. However, this assumption neglects the fact that polarized Galactic foregrounds in a given portion of the sky may have non-zero EB and TB cross-spectra. If these foreground signals remain in the observations, then they will bias the self-calibrated telescope polarization angle and produce a spurious B-mode signal. In this paper, we estimate the foreground-induced bias for various instrument configurations and then expand the self-calibration formalism to account for polarized foreground signals. Assuming the EB correlation signal for dust is in the range constrained by angular power spectrum measurements from Planck at 353 GHz (scaled down to 150 GHz), then the bias is negligible for high angular resolution experiments, which have access to CMB-dominated high 'ell' modes with which to self-calibrate. Low-resolution experiments observing particularly dusty sky patches can have a bias as large as 0.5°. A miscalibration of this magnitude generates a spurious BB signal corresponding to a tensor-to-scalar ratio of approximately r ~ 2 × 10-3, within the targeted range of planned experiments.

  20. 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.

  1. Foreground-induced biases in CMB polarimeter self-calibration

    NASA Astrophysics Data System (ADS)

    Abitbol, Maximilian H.; Hill, J. Colin; Johnson, Bradley R.

    2016-04-01

    Precise polarization measurements of the cosmic microwave background (CMB) require accurate knowledge of the instrument orientation relative to the sky frame used to define the cosmological Stokes parameters. Suitable celestial calibration sources that could be used to measure the polarimeter orientation angle are limited, so current experiments commonly `self-calibrate.' The self-calibration method exploits the theoretical fact that the EB and TB cross-spectra of the CMB vanish in the standard cosmological model, so any detected EB and TB signals must be due to systematic errors. However, this assumption neglects the fact that polarized Galactic foregrounds in a given portion of the sky may have non-zero EB and TB cross-spectra. If these foreground signals remain in the observations, then they will bias the self-calibrated telescope polarization angle and produce a spurious B-mode signal. In this paper, we estimate the foreground-induced bias for various instrument configurations and then expand the self-calibration formalism to account for polarized foreground signals. Assuming the EB correlation signal for dust is in the range constrained by angular power spectrum measurements from Planck at 353 GHz (scaled down to 150 GHz), then the bias is negligible for high angular resolution experiments, which have access to CMB-dominated high ℓ modes with which to self-calibrate. Low-resolution experiments observing particularly dusty sky patches can have a bias as large as 0.5°. A miscalibration of this magnitude generates a spurious BB signal corresponding to a tensor-to-scalar ratio of approximately r ˜ 2 × 10-3, within the targeted range of planned experiments.

  2. 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.

  3. The project of installing a ZIMPOL_3 polarimeter at GREGOR in Tenerife

    NASA Astrophysics Data System (ADS)

    Bianda, M.; Ramelli, R.; Stenflo, J.; Berdyugina, S.; Gisler, D.; Defilippis, I.; Bello González, N.

    A project of collaboration between Kiepenheuer Institut für Sonnenphysik, KIS, and Istituto Ricerche Solari Locarno, IRSOL, includes the installation of a ZIMPOL_3 high resolution polarimeter at the 1.5 meter aperture solar telescope GREGOR in Tenerife. Important scientific topics are expected to be investigated, in particular in the case of events showing faint amplitude polarization signatures like scattering polarization effects, and the Hanle effect. This project has also a technical importance, this combination can be used as test bench for future polarimeters to be installed on the new generation solar telescopes.

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

    PubMed

    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. PMID:26931886

  5. 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.

  6. 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%.

  7. Characterization of a visible spectrum division-of-focal-plane polarimeter.

    PubMed

    York, Timothy; Gruev, Viktor

    2012-08-01

    The development of high resolution division-of-focal-plane polarimeters in the visible spectrum allows real-time capture of two chief properties of interest, the degree of linear polarization and the angle of polarization. The accuracy of these two parameters can be influenced by a number of factors in the imaged scene, from the incident intensity and wavelength to the lens used for image capture. The alignment, transmission, and contrast ratios of the pixel matched filters also impact the measured parameters. A system of measurements is presented here that shows how these factors can determine the quality of a division-of-focal-plane polarimeter. PMID:22859027

  8. Synthetic Jets

    NASA Technical Reports Server (NTRS)

    Milanovic, Ivana M.

    2003-01-01

    Current investigation of synthetic jets and synthetic jets in cross-flow examined the effects of orifice geometry and dimensions, momentum-flux ratio, cluster of orifices, pitch and yaw angles as well as streamwise development of the flow field. This comprehensive study provided much needed experimental information related to the various control strategies. The results of the current investigation on isolated and clustered synthetic jets with and without cross-flow will be further analyzed and documented in detail. Presentations at national conferences and publication of peer- reviewed journal articles are also expected. Projected publications will present both the mean and turbulent properties of the flow field, comparisons made with the data available in an open literature, as well as recommendations for the future work.

  9. Numerical simulations of protostellar jets

    NASA Astrophysics Data System (ADS)

    Suttner, Gerhard; Smith, Michael D.; Yorke, Harold W.; Zinnecker, Hans

    Molecular jets announce the successful birth of a protostar. We develop here a model for the jets and their environments, adapting a multi-dimensional hydrocode to follow the molecular-atomic transitions of hydrogen. We examine powerful outflows into dense gas. The cocoon which forms around a jet is a very low density cavity of atomic gas. These atoms originate from strong shocks which dissociate the molecules. The rest of the molecules are either within the jet or swept up into very thin layers. Pulsed jets produce wider cavities and molecular layers which can grow onto resolvable jet knots. Three-dimensional simulations produce shocked molecular knots, distorted and multiple bow shocks and arclike structures. Spectroscopic and excitation properties of the hydrogen molecules are calculated. In the infrared, strong emission is seen from shocks within the jet (when pulsed) as well as from discrete regions along the cavity walls. Excitation, as measured by line ratios, is not generally constant. Broad double-peaked, shifted emission lines are predicted. The jet model for protostellar outflows is confronted with the constraints imposed by CO spectroscopic observations. From the three dimensional simulations we calculate line profiles and construct position-velocity diagrams for the (low-J) CO transitions. We find (1) the profiles imply power law variation of integrated brightness with velocity over a wide range of velocities, (2) the velocity field resembles a `Hubble Law' and (3) a hollow-shell structure at low velocities becomes an elongated lobe at high velocities. Deviations from the simple power law dependence of integrated brightness versus velocity occur at high velocities in our simulations. The curve first dips to a shallow minimum and then rises rapidly and peaks sharply. Reanalysis of the NGC 2264G and Cepheus E data confirm these predictions. We identify these two features with a jet-ambient shear layer and the jet itself. A deeper analysis reveals that

  10. Numerical and Experimental Study of Mixing Properties of Gaseous Fuels Jets Including Hydrogen and Methane Into the non-Swirl Main Flow in a Premixer Configuration

    NASA Astrophysics Data System (ADS)

    Akbari, Amin

    The mixing of fuel and air has a significant impact on overall operation efficiency and emissions performance of combustion systems, especially in lean combustion applications. As a result, developing an understanding of the processes associated with the fuel/air mixing is important. In parallel with the evolution of lean combustion, a new generation of fuels is emerging as an alternative to conventional fuels. Thus, it is desirable to study the mixing properties of different fuels from conventional resources, such as methane, as well as from renewable resources, such as hydrogen. One tool that is available to study mixing in complex (e.g., turbulent and elliptic) flows is computational fluid dynamics (CFD). In the present work, mixing of hydrogen and methane into air, for example, is simulated using various CFD approaches. Fuel is injected either co-flowing to the air flow ("axial injection") or perpendicular to the air flow ("radial injection"). The quality of the simulations is evaluated by comparing the numerical results with experimental measurements. Qualitative and quantitative comparisons are used to evaluate the relative accuracy of different CFD approaches to simulate the mixing characteristics. Reynolds Averaged Navier-Stokes (RANS) turbulent models are utilized to model all the cases as steady turbulent models. Moreover, unsteady turbulent models, such as Unsteady RANS, and Large Eddy Simulation (LES) are used to provide information about unsteady features in selected cases. The sensitivity of numerical predictions to different RANS turbulence models as well as to different turbulent Schmidt numbers are explored. The results indicate more sensitivity to turbulence models for radial injection configurations. However, for the axial configuration, more sensitivity to Sct is observed. In general, the RSM turbulence model with Sc t=0.7 provides the most promising predictions for various combination of different fuels and injection types.

  11. Preflight performance studies of the PoGOLite hard X-ray polarimeter

    NASA Astrophysics Data System (ADS)

    Chauvin, M.; Jackson, M.; Kawano, T.; Kiss, M.; Kole, M.; Mikhalev, V.; Moretti, E.; Takahashi, H.; Pearce, M.

    2016-01-01

    Polarimetric studies of astrophysical sources can make important contributions to resolve the geometry of the emitting region and determine the photon emission mechanism. PoGOLite is a balloon-borne polarimeter operating in the hard X-ray band (25-240 keV), with a Pathfinder mission focussing on Crab observations. Within the polarimeter, the distribution of Compton scattering angles is used to determine the polarisation fraction and angle of incident photons. To assure an unbiased measurement of the polarisation during a balloon flight it is crucial to characterise the performance of the instrument before the launch. This paper presents the results of the PoGOLite calibration tests and simulations performed before the 2013 balloon flight. The tests performed confirm that the polarimeter does not have any intrinsic asymmetries and therefore does not induce bias into the measurements. Generally, good agreement is found between results from test data and simulations which allows the polarimeter performance to be estimated for Crab observations.

  12. The GEMS X-Ray Polarimeter: Instrument Concept and Calibration Requirements

    NASA Technical Reports Server (NTRS)

    Jahoda, Keith

    2010-01-01

    The instrument and detector concepts for the Gravity and Extreme Magnetism Small Explorer (GEMS) X-ray polarimetry mission will be presente d. The calibration requirements for astrophysical X-ray polarimeters in general and GEMS in particular will be discussed.

  13. A Novel Spin-Light Polarimeter for the Electron Ion Collider

    NASA Astrophysics Data System (ADS)

    Mohanmurthy, Prajwal; Dutta, Dipangkar

    2013-04-01

    High precision polarimetry is a pre-requisite for the suite of precision experiments being planned for the proposed Electron Ion Collider. A novel polarimeter based on the asymmetry in the spacial distribution of the spin light component of synchrotron radiation will make for a fine addition to the existing-conventional Møller and Compton polarimeters. The spin light polarimeter consists of a set of wiggler magnet along the beam that generate synchrotron radiation. The spacial distribution of synchrotron radiation will be measured by an ionization chamber. The up-down (below and above the wiggle) spacial asymmetry in the transverse plain is used to quantify the polarization of the beam. As a part of the design process, the fringe fields of the wiggler magnet was simulated using a 2-D magnetic field simulation toolkit called Poisson Superfish, which is maintained by Los Alamos National Laboratory. The effects of the fringe field was found to be negligible. Lastly, a full fledged GEANT-4 simulation was built to study the response of the ionization chamber. The results from all the simulations carried out, the preliminary design parameters of the polarimeter and its impact will be discussed.

  14. Examining IFOV error and demodulation strategies for infrared microgrid polarimeter imagery

    NASA Astrophysics Data System (ADS)

    Ratliff, Bradley M.; Tyo, J. Scott; LaCasse, Charles F.; Black, Wiley T.

    2009-08-01

    For the past several years we have been working on strategies to mitigate the effects of IFOV errors on LWIR microgrid polarimeters. In this paper we present a detailed, theoretical analysis of the source of IFOV error in the frequency domain, and show a frequency domain strategy to mitigate those effects.

  15. Stellar X-ray polarimeter polarizer development and calibration at LEA/LLNL

    SciTech Connect

    Ziock, K.; Silver, E.; Raffanti, M.

    1993-12-31

    A large area thin graphite crystal and a lithium scattering block are used as the polarization sensitive elements of the Stellar X-Ray Polarimeter (SXRP). The authors discuss the construction, selection and characterization of these two polarizing elements. In addition, they describe the plans for calibration of the completed instrument and the facility where it will be conducted.

  16. 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.

  17. Analysis of the new polarimeter for the Marshall Space Flight Center vector magnetograph

    NASA Technical Reports Server (NTRS)

    West, E. A.

    1985-01-01

    The magnetograph was upgraded in both electronic control of the magnetograph hardware and in the polarization optics. The problems associated with the orignal polarimeter were: (1) field of view errors associated with the natural birefringence of the KD*P crystals; (2.) KD*P electrode failure due to the halfwave dc voltage required in one of the operational sequences; and (3) breakdown of the retardation properties of some KD*Ps when exposed to a zero to halfwave modulation (DC) scheme. The new polarimeter gives up the flexibility provided by two variable waveplates to adjust the retardances of the optics for a particular polarization measurement, but solves the problems associated with the original polarimeter. With the addition of the quartz quarterwave plates, a new optical alignment was developed to allow the remaining KD*P to correct for errors in the waveplates. The new optical alignment of the polarimeter is prescribed. The various sources of error, and how those errors are minimized so that the magnetograph can look at the transverse field in real time are discussed.

  18. Cryogenic hydrogen release research.

    SciTech Connect

    LaFleur, Angela Christine

    2015-12-01

    The objective of this project was to devolop a plan for modifying the Turbulent Combustion Laboratory (TCL) with the necessary infrastructure to produce a cold (near liquid temperature) hydrogen jet. The necessary infrastructure has been specified and laboratory modifications are currently underway. Once complete, experiments from this platform will be used to develop and validate models that inform codes and standards which specify protection criteria for unintended releases from liquid hydrogen storage, transport, and delivery infrastructure.

  19. 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.

  20. Jet aircraft hydrocarbon fuels technology

    NASA Technical Reports Server (NTRS)

    Longwell, J. P. (Editor)

    1978-01-01

    A broad specification, referee fuel was proposed for research and development. This fuel has a lower, closely specified hydrogen content and higher final boiling point and freezing point than ASTM Jet A. The workshop recommended various priority items for fuel research and development. Key items include prediction of tradeoffs among fuel refining, distribution, and aircraft operating costs; combustor liner temperature and emissions studies; and practical simulator investigations of the effect of high freezing point and low thermal stability fuels on aircraft fuel systems.

  1. Jets in air-jet family

    NASA Technical Reports Server (NTRS)

    Navia, C. E.; Sawayanagi, K.

    1985-01-01

    The A-jet families on Chacaltaya emulsion chamber experiments were analyzed by the study of jets which are reconstructed by a grouping procedure. It is demonstrated that large-E sub J R sub J events are characterized by small number of jets and two-jet like asymmetric shape, binocular events and the other type. This type has a larger number of jets and more symmetrical shape in the P sub t plane.

  2. Marine Jet

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The marine turbine pump pictured is the Jacuzzi 12YJ, a jet propulsion system for pleasure or commercial boating. Its development was aided by a NASA computer program made available by the Computer Software Management and Information Center (COSMIC) at the University of Georgia. The manufacturer, Jacuzzi Brothers, Incorporated, Little Rock, Arkansas, used COSMIC'S Computer Program for Predicting Turbopump Inducer Loading, which enabled substantial savings in development time and money through reduction of repetitive testing.

  3. DICHOTOMY OF SOLAR CORONAL JETS: STANDARD JETS AND BLOWOUT JETS

    SciTech Connect

    Moore, Ronald L.; Cirtain, Jonathan W.; Sterling, Alphonse C.; Falconer, David A.

    2010-09-01

    By examining many X-ray jets in Hinode/X-Ray Telescope coronal X-ray movies of the polar coronal holes, we found that there is a dichotomy of polar X-ray jets. About two thirds fit the standard reconnection picture for coronal jets, and about one third are another type. We present observations indicating that the non-standard jets are counterparts of erupting-loop H{alpha} macrospicules, jets in which the jet-base magnetic arch undergoes a miniature version of the blowout eruptions that produce major coronal mass ejections. From the coronal X-ray movies we present in detail two typical standard X-ray jets and two typical blowout X-ray jets that were also caught in He II 304 A snapshots from STEREO/EUVI. The distinguishing features of blowout X-ray jets are (1) X-ray brightening inside the base arch in addition to the outside bright point that standard jets have, (2) blowout eruption of the base arch's core field, often carrying a filament of cool (T {approx} 10{sup 4} - 10{sup 5} K) plasma, and (3) an extra jet-spire strand rooted close to the bright point. We present cartoons showing how reconnection during blowout eruption of the base arch could produce the observed features of blowout X-ray jets. We infer that (1) the standard-jet/blowout-jet dichotomy of coronal jets results from the dichotomy of base arches that do not have and base arches that do have enough shear and twist to erupt open, and (2) there is a large class of spicules that are standard jets and a comparably large class of spicules that are blowout jets.

  4. Dichotomy of Solar Coronal Jets: Standard Jets and Blowout Jets

    NASA Technical Reports Server (NTRS)

    Moore, R. L.; Cirtain, J. W.; Sterling, A. C.; Falconer, D. A.

    2010-01-01

    By examining many X-ray jets in Hinode/XRT coronal X-ray movies of the polar coronal holes, we found that there is a dichotomy of polar X-ray jets. About two thirds fit the standard reconnection picture for coronal jets, and about one third are another type. We present observations indicating that the non-standard jets are counterparts of erupting-loop H alpha macrospicules, jets in which the jet-base magnetic arch undergoes a miniature version of the blowout eruptions that produce major CMEs. From the coronal X-ray movies we present in detail two typical standard X-ray jets and two typical blowout X-ray jets that were also caught in He II 304 Angstrom snapshots from STEREO/EUVI. The distinguishing features of blowout X-ray jets are (1) X-ray brightening inside the base arch in addition to the outside bright point that standard jets have, (2) blowout eruption of the base arch's core field, often carrying a filament of cool (T 10(exp 4) - 10(exp 5) K) plasma, and (3) an extra jet-spire strand rooted close to the bright point. We present cartoons showing how reconnection during blowout eruption of the base arch could produce the observed features of blowout X-ray jets. We infer that (1) the standard-jet/blowout-jet dichotomy of coronal jets results from the dichotomy of base arches that do not have and base arches that do have enough shear and twist to erupt open, and (2) there is a large class of spicules that are standard jets and a comparably large class of spicules that are blowout jets.

  5. Jet initiation of deflagration and detonation

    NASA Astrophysics Data System (ADS)

    Krok, James Christopher

    We have constructed a facility for the study of jet-initiated deflagration and detonation in hydrogen-air-steam mixtures. The facility is built around two pressure vessels. Mixtures of hydrogen, oxygen and nitrogen are spark-ignited in the driver vessel, generating a hot mixture of combustion products. The pressure rise ruptures a diaphragm, venting the products into the receiver vessel through nozzles of 12.7-92 mm diameter. The receiver is filled with hydrogen-air and hydrogen-oxygen mixtures diluted with either nitrogen or steam. The deflagration tests studied the lean and maximum-dilution limits of hydrogen-air mixtures ignited by a hydrogen-steam jet. The lean limit of 6% hydrogen was comparable to other studies. The maximum dilution limit for steam was 60%. This is higher than the limit found in spark/glow plug ignition experiments. Shock oscillations in the receiver increased with nozzle size. Further tests studied the initiation of detonation in both hydrogen-air and stoichiometric hydrogen-oxygen-diluent mixtures. In terms of jet diameter, D, and receiver detonation cell size, lambda, we found initiation limits of 2jet initiation, as it does not reflect the conditions in the driver. The tests indicated that shock focusing plays an important role, promoting strong secondary explosions with or without prompt initiation of detonation. Mixtures with steam dilution were prone to DDT near the detonation limit, as the slower flame speed allows shock reflection and pressurization to occur before the reactants are consumed. Tests with nitrogen dilution had no DDT regime. Because of DDT and shock focusing, peak pressures were highest in mixtures that were slightly less sensitive than the detonation threshold. Schlieren movies confirmed the formation of a detonation near the nozzle exit.

  6. Jet initiation of deflagration and detonation

    NASA Astrophysics Data System (ADS)

    Krok, James Christopher

    We have constructed a facility for the study of jet-initiated deflagration and detonation in hydrogen-air-steam mixtures. The facility is built around two pressure vessels. Mixtures of hydrogen, oxygen and nitrogen are spark-ignited in the driver vessel, generating a hot mixture of combustion products. The pressure rise ruptures a diaphragm, venting the products into the receiver vessel through nozzles of 12.7-92 mm diameter. The receiver is filled with hydrogen-air and hydrogen-oxygen mixtures diluted with either nitrogen or steam.The deflagration tests studied the lean and maximum-dilution limits of hydrogen-air mixtures ignited by a hydrogen-steam jet. The lean limit of 6% hydrogen was comparable to other studies. The maximum dilution limit for steam was 60%. This is higher than the limit found in spark/glow plug ignition experiments. Shock oscillations in the receiver increased with nozzle size.Further tests studied the initiation of detonation in both hydrogen-air and stoichiometric hydrogen-oxygen-diluent mixtures. In terms of jet diameter, D, and receiver detonation cell size, [?], we found initiation limits of 2 < D[?] < 7, where other experiments required a D[?] of 11 or more. We propose that the D[?] model does not adequately characterize jet initiation, as it does not reflect the conditions in the driver.The tests indicated that shock focusing plays an important role, promoting strong secondary explosions with or without prompt initiation of detonation. Mixtures with steam dilution were prone to DDT near the detonation limit, as the slower flame speed allows shock reflection and pressurization to occur before the reactants are consumed. Tests with nitrogen dilution had no DDT regime. Because of DDT and shock focusing, peak pressures were highest in mixtures that were slightly less sensitive than the detonation threshold. Schlieren movies confirmed the formation of a detonation near the nozzle exit.

  7. Extremely weak hydrogen flames

    SciTech Connect

    Lecoustre, V.R.; Sunderland, P.B.; Chao, B.H.; Axelbaum, R.L.

    2010-11-15

    Hydrogen jet diffusion flames were observed near their quenching limits. These involved downward laminar flow of hydrogen from a stainless steel hypodermic tube with an inside diameter of 0.15 mm. Near their quenching limits these flames had hydrogen flow rates of 3.9 and 2.1 {mu}g/s in air and oxygen, respectively. Assuming complete combustion, the associated heat release rates are 0.46 and 0.25 W. To the authors' knowledge, these are the weakest self-sustaining steady flames ever observed. (author)

  8. Method and means for producing solid evacuated microspheres of hydrogen

    DOEpatents

    Turnbull, Robert J.; Foster, Christopher A.; Hendricks, Charles D.

    1976-01-01

    A method is provided for producing solid, evacuated microspheres comprised of hydrogen. The spheres are produced by forming a jet of liquid hydrogen and exciting mechanical waves on the jet of appropriate frequency so that the jet breaks up into drops with a bubble formed in each drop by cavitation. The drops are exposed to a pressure less than the vapor pressure of the liquid hydrogen so that the bubble which is formed within each drop expands. The drops which contain bubbles are exposed to an environment having a pressure just below the triple point of liquid hydrogen and they thereby freeze giving solid, evacuated spheres of hydrogen.

  9. The development of the imaging polarimeter's polarizer on the basis of the polarizing film

    NASA Astrophysics Data System (ADS)

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

    2015-07-01

    Work has begun on the developing of the scientific equipment "Spectrometer polarimeter", which is planned as one of five devices that form part of the Russian-Ukrainian space experiment "Planetary Monitoring". The devices are designed to form images of celestial objects in the focal plane of a planetary telescope (PT-600) and to register spectral and polarimetric information on gas and aerosol composition of the atmospheres of planets and physics and chemical properties of the surface layers of atmosphereless astronomical bodies. A model of a polarizer based on the use of polarizing films has been designed. This model can be used in the spectrometer-polarimeter. The results of the investigation of the polarizer in the spectral range 420-850 nm are given.

  10. The Bragg Reflection Polarimeter On the Gravity and Extreme Magnetism Small Explorer Mission

    NASA Astrophysics Data System (ADS)

    Allured, Ryan; Kaaret, P.; GEMS Team

    2011-05-01

    The strong gravity associated with black holes warps the spacetime outside of the event horizon, and it is predicted that this will leave characteristic signatures on the polarization of X-ray emission originating in the accretion disk. The Gravity and Extreme Magnetism Small Explorer (GEMS) mission will be the first observatory with the capability to make polarization measurements with enough sensitivity to quantitatively test this prediction. Students at the University of Iowa are currently working on the development of the Bragg Reflection Polarimeter (BRP), a soft X-ray polarimeter, sensitive at 500 eV, that is the student experiment on GEMS. The BRP will complement the main experiment by making a polarization measurement from accreting black holes below the main energy band (2-10 keV). This measurement will constrain the inclination of the accretion disk and tighten measurements of black hole spin.

  11. The Bragg Reflection Polarimeter On the Gravity and Extreme Magnetism Small Explorer Mission

    NASA Astrophysics Data System (ADS)

    Allured, Ryan; Griffiths, S.; Daly, R.; Prieskorn, Z.; Marlowe, H.; Kaaret, P.; GEMS Team

    2011-09-01

    The strong gravity associated with black holes warps the spacetime outside of the event horizon, and it is predicted that this will leave characteristic signatures on the polarization of X-ray emission originating in the accretion disk. The Gravity and Extreme Magnetism Small Explorer (GEMS) mission will be the first observatory with the capability to make polarization measurements with enough sensitivity to quantitatively test this prediction. Students at the University of Iowa are currently working on the development of the Bragg Reflection Polarimeter (BRP), a soft X-ray polarimeter sensitive at 500 eV, that is the student experiment on GEMS. The BRP will complement the main experiment by making a polarization measurement from accreting black holes below the main energy band (2-10 keV). This measurement will constrain the inclination of the accretion disk and tighten measurements of black hole spin.

  12. Elastic scattering polarimeter for a polarized antiproton beam at U-70 accelerator of IHEP

    NASA Astrophysics Data System (ADS)

    Bogdanov, A. A.; Chetvertkov, M. A.; Chetvertkova, V. A.; Garkusha, V. I.; Meschanin, A. P.; Mochalov, V. V.; Nurusheva, M. B.; Nurushev, S. B.; Ridiger, A. V.; Rykov, V. L.; Semenov, P. A.; Strikhanov, M. N.; Vasiliev, A. N.; Zapolsky, V. N.

    2016-02-01

    The absolute polarimeter based on the elastic p¯p-scattering in the diffraction kinematic regions with the total momentum transfer squared coverage of 0.1 < - t < 0.3 (GeV/c)2 is proposed for the polarized antiproton beam at the U-70 proton synchrotron of IHEP. It is shown that it would take ˜200-400 hours for measuring the beam polarization at the statistical errors of ΔPB/PB ≃10-15%. These time estimates include also the time which is necessary for the measurements of an analyzing power AN, using a polarized target. Besides the measurements of beam polarizations, the proposed polarimeter provides an opportunity for carrying out the experimental studies of the small momentum transfers physics which would be a valuable enrichment of the SPASCHARM experiment capabilities and its physics program.

  13. SXRP - An X-ray polarimeter for the SPECTRUM-X-Gamma mission

    NASA Technical Reports Server (NTRS)

    Costa, E.; Piro, L.; Soffitta, P.; Massaro, E.; Matt, G.; Perola, G. C.; Giarrusso, S.; La Rosa, G.; Manzo, G.; Santangelo, A.

    1992-01-01

    The Stellar X-ray Polarimeter (SXRP) is a focal plane instrument which will be flown on the SPECTRUM-X-Gamma mission in 1993. The polarimeter is composed of two separate instruments: the first exploits the dependence on the polarization of the Bragg reflection from a graphite crystal, and of the Thomson scattering from a metallic lithium target. The second instrument makes use of the recently discovered polarization dependence of X-ray photoemission from CsI. The SXRP will permit sensitive measurements of several classes of galactic X-ray sources, such as X-ray pulsars, black-hole candidates and supernova remnants. Moreover, and for the first time, SXRP will be able to perform highly sensitive measurements of the brightest extragalactic sources.

  14. Two long-wave infrared spectral polarimeters for use in understanding polarization phenomenology

    NASA Astrophysics Data System (ADS)

    Sposato, Stephanie H.; Fetrow, Matthew P.; Bishop, Kenneth P.; Caudill, Thomas R.

    2002-05-01

    Spectrally varying long-wave infrared (LWIR) polarization measurements can be used to identify materials and to discriminate samples from a cluttered background. Two LWIR instruments have been built and fielded by the Air Force Research Laboratory: a multispectral LWIR imaging polarimeter (LIP) and a full-Stokes Fourier transform infrared (FTIR) spectral polarimeter (FSP), constructed for higher spectral resolution measurements of materials. These two instruments have been built to gain an understanding of the polarization signatures expected from different types of materials in a controlled laboratory and in varying field environments. We discuss the instruments, calibration methods, general operation, and measurements characterizing the emitted polarization properties of materials as a function of wavelength. The results show that we are able to make polarization measurements with a relative accuracy of 0.5% degree of polarization (DOP) between two different instruments that are calibrated with the same techniques, and that these measurements can improve the understanding of polarization phenomenology.

  15. 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.

  16. 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.

  17. 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.

    2016-03-01

    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.

  18. Multilayer-based soft X-ray polarimeter at the Beijing Synchrotron Radiation Facility

    NASA Astrophysics Data System (ADS)

    Sun, Li-Juan; Cui, Ming-Qi; Zhu, Jie; Zhao, Yi-Dong; Zheng, Lei; Wang, Zhan-Shan; Zhu, Jing-Tao

    2013-07-01

    A compact high precision eight-axis automatism and two-axis manual soft-ray polarimeter with a multilayer has been designed, constructed, and installed in 3W1B at the Beijing Synchrotron Radiation Facility (BSRF). Four operational modes in the same device, which are double-reflection, double-transmission, front-reflection-behind-transmission and front-transmission-behind-reflection, have been realized. It can be used for the polarization analysis of synchrotron radiation. It also can be used to characterize the polarization properties of the optical elements in the soft X-ray energy range. Some experiments with Mo/Si and Cr/C multilayers have been performed by using this polarimeter with good results obtained.

  19. 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.

  20. A Polarimeter for GeV Linearly-polarized Photon Beams

    NASA Astrophysics Data System (ADS)

    Wood, M. H.; Tedeschi, D.; Wojtsekhowski, B.; Abbott, D.; Nelyubin, V.; Vlahovic, B.; Asai, J.; Feldman, G.; O'Rielly, G.; Khandaker, Mahbub; Hotta, T.; Kohri, H.; Matsumura, T.; Mibe, T.; Nakano, T.; Yorita, T.; Rudge, A.; Weilhammer, P.; Zegers, R.

    2003-04-01

    We have built a polarimeter for linearly-polarized photon beams in the few GeV photon-energy range. The technique is to detect an electron-positron pair produced from a photon incident on a thin converter. The orientation and the distance separating the e^+ and e^- are measured accurately with silicon-microstrip detectors. The polarimeter was calibrated at the SPring-8 facility using a compton-backscattered photon beam in the energy range of 1.5 GeV ≤ E_γ ≤ 2.4 GeV. This measurement was the first made for the process at these energies. Results will be presented of the measured asymmetry between horizontally and vertically polarized beams.

  1. SolpeX: the soft X-ray flare polarimeter-spectrometer for the ISS

    NASA Astrophysics Data System (ADS)

    Sylwester, Janusz; Płocieniak, Stefan; Bakała, Jarosław; Szaforz, Żaneta; Stȩślicki, Marek; Ścisłowski, Daniel; Kowaliński, Mirosław; Podgórski, Piotr; Hernandez, Jose; Shestov, Sergey

    2015-10-01

    We present the innovative soft X-ray spectro-polarimeter, SolpeX. This instrument consists of three functionally independent blocks. They are to be included into the Russian instrument KORTES, to be mounted onboard the ISS. The three SolpeX units are: a simple pin-hole X-ray spectral imager, a polarimeter, and a fast-rotating drum multiple-flat-crystal Bragg spectrometer. Such a combination of measuring blocks will offer a new opportunity to reliably measure possible X-ray polarization and spectra of solar flares, in particular during the impulsive phase. Polarized Bremsstrahlung and line emission due to the presence of directed particle beams will be detected, and measurements of the velocities of evaporated hot plasma will be made. In this paper we discuss the details of the construction of the SolpeX units. The delivery of KORTES with SolpeX to the ISS is expected to happen in 2017/2018.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Image interpolation for division of focal plane polarimeters with intensity correlation.

    PubMed

    Zhang, Junchao; Luo, Haibo; Hui, Bin; Chang, Zheng

    2016-09-01

    Division of focal plane (DoFP) polarimeters operate by integrating micro-polarizer elements with a focal plane. These polarization imaging sensors reduce spatial resolution output and each pixel has a varying instantaneous field of view (IFoV). These drawbacks can be mitigated by applying proper interpolation methods. In this paper, we present a new interpolation method for DoFP polarimeters by using intensity correlation. We employ the correlation of intensity measurements in different orientations to detect edges and then implement interpolation along edges. The performance of the proposed method is compared with several previous methods by using root mean square error (RMSE) comparison and visual comparison. Experimental results showed that our proposed method can achieve better visual effects and a lower RMSE than other methods. PMID:27607683

  7. 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.

    2016-04-01

    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.

  8. 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.

  9. 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.

  10. Microsphere plate detectors used with a compact Mott polarimeter for time-of-flight studies

    SciTech Connect

    Snell, G.; Viefhaus, J.; Dunning, F. B.; Berrah, N.

    2000-06-01

    A compact retarding-potential Mott polarimeter combined with microsphere plates (MSP) as electron detectors was built to perform spin-resolved time-of-flight electron spectroscopy. The comparison of the performance of MSP and channeltron detectors shows that the MSP detector has a better time resolution but a lower efficiency. The overall time resolution of the system was determined to be 350 ps using synchrotron radiation pulses. (c) 2000 American Institute of Physics.

  11. Compton polarimeter as a focal plane detector for hard X-ray telescope

    NASA Astrophysics Data System (ADS)

    Chattopadhyay, T.; Vadawale, S. V.

    X-ray polarimetry is expected to provide unique opportunity to study the behavior of matter and radiation under extreme magnetic fields and extreme gravitational fields. However sensitivity of the X-ray polarimeters has always been an issue for the last three decades; there is almost no progress in this field whereas there is a significant advance in the fields of X-ray spectroscopy, imaging and timing. Recently significant improvement in the sensitivity is expected in polarimetric measurements using GEM-based photoelectron tracking polarimeters coupled to soft X-ray telescopes. However they are sensitive in the soft X-ray regime. On the other hand mostly for the X-ray sources higher degree of polarisation at hard X-rays is expected because of the dominance of nonthermal X-ray emission mechanisms over the thermal counterpart. So polarisation measurement in hard X-ray can yield significant insights into such processes. Of late with the advent of high energy focussing telescopes (e.g. Nu STAR, ASTRO-H), sensitivity of X-ray detectors in hard X-ray range is expected to improve significantly. In this context we explore feasibility of a focal plane hard X-ray polarimeter based on Compton scattering having a thin plastic scatterer surrounded by cylindrical array of scintillator detectors. We have carried out detailed Geant4 simulations to estimate the modulation factor for 100% polarized beam as well as polarimetric efficiency of this configuration. Polarimetric sensitivity of the instrument critically depends on low energy threshold in central plastic scatterer. We estimated the sensitivity for a range of plastic threshold energy. We also discuss the methodology to measure the threshold energy in plastic scatterer. Here we present the initial results of polarisation sensitivities of such focal plane Compton polarimeter coupled with the reflection efficiency of present era hard X-ray optics and the experimental results for threshold measurements in plastic.

  12. 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.

  13. Compton polarimeter for 10-30 keV x rays.

    PubMed

    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. PMID:26429432

  14. 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.

  15. PolKa: A New Polarimeter for Millimeter and Submillimeter Bolometer Arrays

    NASA Astrophysics Data System (ADS)

    Siringo, G.; Kreysa, E.; Reichertz, L. A.; Menten, K. M.

    2004-02-01

    A new concept of polarimeter has been designed to be used together with the arrays of bolometers developed at the Max-Planck-Institut fuer Radioastronomie in Bonn. The new polarimeter has the unique characteristic of being tunable over a wide range of wavelengths and of producing a negligible absorption. It has been used at the Heinrich-Hertz telescope to measure the linear polarization of some quasars and of some extended sources inside our Galaxy. Some results are presented here. We detected polarization on the quasars 3C279 and 1633+382. On 3C279 we also detected polarization variability on a time scale of a week. We performed also maps of extended sources: the BN/KL complex in Orion OMC-1, a filament cloud in Orion OMC-3 and the massive star-forming region IRAS 05358+3543. The polarimeter has low spurious polarization and a high modulation efficiency and the tests at the telescope show that it is well suited to become a permanent facility.

  16. 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.

  17. Image processing methods to compensate for IFOV errors in microgrid imaging polarimeters

    NASA Astrophysics Data System (ADS)

    Ratliff, Bradley M.; Boger, James K.; Fetrow, Matthew P.; Tyo, J. Scott; Black, Wiley T.

    2006-05-01

    Long-wave infrared imaging Stokes vector polarimeters are used in many remote sensing applications. Imaging polarimeters require that several measurements be made under optically different conditions in order to estimate the polarization signature at a given scene point. This multiple-measurement requirement introduces error in the signature estimates, and the errors differ depending upon the type of measurement scheme used. Here, we investigate a LWIR linear microgrid polarimeter. This type of instrument consists of a mosaic of micropolarizers at different orientations that are masked directly onto a focal plane array sensor. In this scheme, each polarization measurement is acquired spatially and hence each is made at a different point in the scene. This is a significant source of error, as it violates the requirement that each polarization measurement have the same instantaneous field-of-view (IFOV). In this paper, we first study the amount of error introduced by the IFOV handicap in microgrid instruments. We then proceed to investigate means for mitigating the effects of these errors to improve the quality of polarimetric imagery. In particular, we examine different interpolation schemes and gauge their performance. These studies are completed through the use of both real instrumental and modeled data.

  18. Bistatic laser polarimeter calibrated to 1% at visible-SWIR wavelengths.

    PubMed

    Hoover, Brian G; Rugely, David A; Francis, Christopher M; Zeira, Gal; Gamiz, Victor L

    2016-08-22

    This paper documents the accuracy and precision of the U. S. Air Force Research Laboratory APCL laser polarimeter in arbitrary bistatic geometries at the three laser wavelengths 633nm, 1064nm, and 1550nm. The difference between measured and theoretical-truth Mueller matrices of calibration components is used as the calibration metric and justified relative to block ellipsometer calibration methods. Calibration of the polarimeter ellipsometry mode is demonstrated first, at quasi-monostatic and large bistatic angles, employing a metallic mirror and a dielectric window as the calibration component, respectively, the latter in order to avoid uncertainty in the retardance of typical metallic mirrors at large incident angles. This uncertainty is demonstrated in measurements of COTS protected-silver mirrors from two vendors, revealing an approximately λ/8 retardance difference, for reflection through 90°, between nominally-identical mirrors from the two vendors. Polarimeter calibration is finally extended beyond ellipsometry by calibrating depolarization measurements using a new technique employing ensembles of polarized states as calibration components. PMID:27557264

  19. Testing of a Narrow Gap Detector designed for a sensitive X-ray polarimeter

    NASA Astrophysics Data System (ADS)

    Gilberto Almonte, Rafael; Hill, Joanne E.; Morris, David C.; Emmett, Thomas

    2015-01-01

    Time projection polarimeters are gas detectors where incident X-rays interact with a gas atom to produce a photoelectron whose direction is correlated with the polarization of the incident X-ray. By imaging the path of many photoelectrons the polarization of the incident X-ray can be determined.The next generation of time projection polarimeter incorporates a narrow gap detector to minimize the diffusion in the transfer gap between the gas electron multiplier and the readout strips. We report on the testing performed to bring the narrow-gap design to Technology Readiness Level (TRL)-6.TRL-6 testing included random and sine burst vibration tests and thermal cycling tests. In addition thermal shock tests and creep tests were performed to further demonstrate that the design would meet requirements, particularly flatness, throughout the life of a 2 year mission.The post-test inspection following the vibration testing showed no degradation or loss of flatness. Thermal Shock testing showed no indication that the extreme temperature had any effect on the detector. Creep testing showed no positive or negative trends in flatness. Thermal cycle testing also showed no change in detector behavior. All the requirements have been met and the narrow gap polarimeter is at TRL-6.

  20. A new three-band, two beam astronomical photo-polarimeter

    NASA Astrophysics Data System (ADS)

    Srinivasulu, G.; Raveendran, A. V.; Muneer, S.; Mekkaden, M. V.; Jayavel, N.; Somashekar, M. R.; Sagayanathan, K.; Ramamoorthy, S.; Rosario, M. J.; Jayakumar, K.

    2014-09-01

    We designed and built a new astronomical photo-polarimeter that can measure linear polarization simultaneously in three spectral bands. It has a Calcite beam-displacement prism as the analyzer. The ordinary and extra-ordinary emerging beams in each spectral bands are quasi-simultaneously detected by the same photomultiplier by using a high speed rotating chopper. A rotating superachromatic Pancharatnam halfwave plate is used to modulate the light incident on the analyzer. The spectral bands are isolated using appropriate dichroic and glass filters. We show that the reduction of 50% in the efficiency of the polarimeter because of the fact that the intensities of the two beams are measured alternately is partly compensated by the reduced time to be spent on the observation of the sky background. The use of a beam-displacement prism as the analyzer completely removes the polarization of background skylight, which is a major source of error during moonlit nights, especially, in the case of faint stars. The field trials that were carried out by observing several polarized and unpolarized stars show the performance of the polarimeter to be satisfactory.

  1. 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. PMID:23126966

  2. Inclusive Jets in PHP

    NASA Astrophysics Data System (ADS)

    Roloff, P.

    Differential inclusive-jet cross sections have been measured in photoproduction for boson virtualities Q^2 < 1 GeV^2 with the ZEUS detector at HERA using an integrated luminosity of 300 pb^-1. Jets were identified in the laboratory frame using the k_T, anti-k_T or SIScone jet algorithms. Cross sections are presented as functions of the jet pseudorapidity, eta(jet), and the jet transverse energy, E_T(jet). Next-to-leading-order QCD calculations give a good description of the measurements, except for jets with low E_T(jet) and high eta(jet). The cross sections have the potential to improve the determination of the PDFs in future QCD fits. Values of alpha_s(M_Z) have been extracted from the measurements based on different jet algorithms. In addition, the energy-scale dependence of the strong coupling was determined.

  3. Corporate Jet

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Gulfstream Aerospace Corporation, Savannah, GA, used a version of a NASA program called WIBCO to design a wing for the Gulfstream IV (G-IV) which will help to reduce transonic drag (created by shock waves that develop as an airplane approaches the speed of sound). The G-IV cruises at 88 percent of the speed of sound, and holds the international record in its class for round-the-world flight. They also used the STANS5 and Profile programs in the design. They will use the NASA program GASP to help determine the gross weight, range, speed, payload and optimum wing area of an intercontinental supersonic business jet being developed in cooperation with Sukhoi Design Bureau, a Soviet organization.

  4. The JENSA Gas Jet Target

    NASA Astrophysics Data System (ADS)

    Chipps, K. A.

    2014-03-01

    With the construction of next-generation radioactive ion beam (RIB) facilities, the study of many rare and unstable isotopes previously unattainable will be made possible. In order to take full advantage of possible measurements with these new isotope beams, improvements in detectors and targets are necessary. The Jet Experiments in Nuclear Structure and Astrophysics (JENSA) gas jet target is a new and cutting-edge target system, designed to provide a target of light gas, such as hydrogen or helium, that is localized, dense, and pure. In order to accomplish this, the JENSA system involves nearly two dozen vacuum pumps, differential pumping stages, a custom-built industrial compressor, and vacuum chambers designed to incorporate large arrays of both charged-particle and gamma-ray detectors. The JENSA gas jet target was originally constructed and characterized at ORNL, and has now moved to the ReA3 hall at the NSCL. Tests at ORNL show the JENSA system is capable of producing the most dense helium jet target for RIB studies in the world. JENSA will form the main target for the proposed SEparator for CApture Reactions (SECAR), and together the two comprise the equipment necessary to facilitate the studies which form the focus of the U.S. experimental nuclear astrophysics community. Work funded by US DOE Office of Science and the NSF.

  5. Jet inclusive cross sections

    SciTech Connect

    Del Duca, V.

    1992-11-01

    Minijet production in jet inclusive cross sections at hadron colliders, with large rapidity intervals between the tagged jets, is evaluated by using the BFKL pomeron. We describe the jet inclusive cross section for an arbitrary number of tagged jets, and show that it behaves like a system of coupled pomerons.

  6. DNS of autoigniting turbulent jet flame

    NASA Astrophysics Data System (ADS)

    Asaithambi, Rajapandiyan; Mahesh, Krishnan

    2014-11-01

    Direct numerical simulation of a round turbulent hydrogen jet injected into vitiated coflowing air is performed at a jet Reynolds number of 10,000 and the results are discussed. A predictor-corrector density based method for DNS/LES of compressible chemically reacting flows is developed and used on a cylindrical grid. A novel strategy to remove the center-line stiffness is developed. A fully developed turbulent pipe flow simulation is prescribed as the velocity inlet for the fuel jet. The flame base is observed to be stabilized primarily by autoignition. Further downstream the flame exhibits a diffusion flame structure with regions of rich and lean premixed regimes flanking the central diffusion flame. The lift-off height is well predicted by a simple relation between the ignition delay of the most-reactive mixture fraction and the streamwise velocity of the jet and coflow.

  7. Supersonic gas jets

    NASA Astrophysics Data System (ADS)

    Dulov, V. G.

    The papers presented in this volume provide an overview of the current state of research in the gas dynamics of jet flows. In particular, attention is given to free supersonic jets and to the interaction of supersonic jets with one another and with obstacles under stationary and nonstationary flow conditions. Papers are presented on a method for calculating a weakly anisotropic supersonic turbulent jet in a subsonic slipstream; composite supersonic jets; the principal gas-dynamic characteristics of the processes occurring in gas-jet-driven shock-wave generators; and the construction of models for supersonic jet flows. For individual items see A84-16902 to A84-16918

  8. "Waveguidability" of idealized jets

    NASA Astrophysics Data System (ADS)

    Manola, Iris; Selten, Frank; Vries, Hylke; Hazeleger, Wilco

    2013-09-01

    It is known that strong zonal jets can act as waveguides for Rossby waves. In this study we use the European Center for Medium-Range Weather Forecasts (ECMWF) reanalysis data to analyze the connection between jets and zonal waves at timescales beyond 10 days. Moreover, a barotropic model is used to systematically study the ability of idealized jets to trap Rossby wave energy ("waveguidability") as a function of jet strength, jet width, and jet location. In general, strongest waveguidability is found for narrow, fast jets. In addition, when the stationary wave number is integer, a resonant response is found through constructive interference. In Austral summer, the Southern Hemispheric jet is closest to the idealized jets considered and it is for this season that similar jet-zonal wave relationships are identified in the ECMWF reanalysis data.

  9. Laser-Sharp Jet Splits Water

    NASA Technical Reports Server (NTRS)

    2008-01-01

    A jet of gas firing out of a very young star can be seen ramming into a wall of material in this infrared image from NASA's Spitzer Space Telescope.

    The young star, called HH 211-mm, is cloaked in dust and can't be seen. But streaming away from the star are bipolar jets, color-coded blue in this view. The pink blob at the end of the jet to the lower left shows where the jet is hitting a wall of material. The jet is hitting the wall so hard that shock waves are being generated, which causes ice to vaporize off dust grains. The shock waves are also heating material up, producing energetic ultraviolet radiation. The ultraviolet radiation then breaks the water vapor molecules apart.

    The red color at the end of the lower jet represents shock-heated iron, sulfur and dust, while the blue color in both jets denotes shock-heated hydrogen molecules.

    HH 211-mm is part of a cluster of about 300 stars, called IC 348, located 1,000 light-years away in the constellation Perseus.

    This image is a composite of infrared data from Spitzer's infrared array camera and its multiband imaging photometer. Light with wavelengths of 3.6 and 4.5 microns is blue; 8-micron-light is green; and 24-micron light is red.

  10. Multi-jet production rates in deep-inelastic muon-proton scattering

    SciTech Connect

    Salgado, C.W. )

    1992-02-01

    Measurements of forward multi-jet production rates in deep-inelastic muon-proton scattering are presented. Data were taken with a 490 GeV muon beam incident on a hydrogen target. Jets were defined using the JADE jet finding algorithm. The measured rates are presented as function of W, the hadronic center-of-mass energy and the jet resolution parameter, [ital y][sub [ital cut

  11. Progress toward hydrogen peroxide micropulsion

    SciTech Connect

    Whitehead, J C; Dittman, M D; Ledebuhr, A G

    1999-07-08

    A new self-pressurizing propulsion system has liquid thrusters and gas jet attitude control without heavy gas storage vessels. A pump boosts the pressure of a small fraction of the hydrogen peroxide, so that reacted propellant can controllably pressurize its own source tank. The warm decomposition gas also powers the pump and is supplied to the attitude control jets. The system has been incorporated into a prototype microsatellite for terrestrial maneuvering tests. Additional progress includes preliminary testing of a bipropellant thruster, and storage of unstabilized hydrogen peroxide in small sealed tanks.

  12. Stretched Inertial Jets

    NASA Astrophysics Data System (ADS)

    Ghabache, Elisabeth; Antkowiak, Arnaud; Seon, Thomas; Villermaux, Emmanuel

    2015-11-01

    Liquid jets often arise as short-lived bursting liquid flows. Cavitation or impact-driven jets, bursting champagne bubbles, shaped-charge jets, ballistospores or drop-on-demand inkjet printing are a few examples where liquid jets are suddenly released. The trademark of all these discharge jets is the property of being stretched, due to the quenching injection. the present theoretical and experimental investigation, the structure of the jet flow field will be unraveled experimentally for a few emblematic occurrences of discharge jets. Though the injection markedly depends on each flow configuration, the jet velocity field will be shown to be systematically and rapidly attracted to the universal stretching flow z/t. The emergence of this inertial attractor actually only relies on simple kinematic ingredients, and as such is fairly generic. The universality of the jet velocity structure will be discussed.

  13. A photoelastic-modulator-based motional Stark effect polarimeter for ITER that is insensitive to polarized broadband background reflections

    NASA Astrophysics Data System (ADS)

    Thorman, A.; Michael, C.; De Bock, M.; Howard, J.

    2016-07-01

    A motional Stark effect polarimeter insensitive to polarized broadband light is proposed. Partially polarized background light is anticipated to be a significant source of systematic error for the ITER polarimeter. The proposed polarimeter is based on the standard dual photoelastic modulator approach, but with the introduction of a birefringent delay plate, it generates a sinusoidal spectral filter instead of the usual narrowband filter. The period of the filter is chosen to match the spacing of the orthogonally polarized Stark effect components, thereby increasing the effective signal level, but resulting in the destructive interference of the broadband polarized light. The theoretical response of the system to an ITER like spectrum is calculated and the broadband polarization tolerance is verified experimentally.

  14. 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.

  15. 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.

  16. 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.

  17. Electronics and signal processing for the multichord far-infrared polarimeter of the RFX experiment

    NASA Astrophysics Data System (ADS)

    Zilli, E.; Milani, F.; O'Gorman, M.; Giudicotti, L.; Prunty, S. L.

    2001-11-01

    This article describes the realization and testing of the electronic system which forms part of the multichannel far-infrared (FIR) polarimeter for the RFX machine, a plasma confinement experiment with Reversed Field Pinch (RFP) configuration. The electronic system, which comprises the detectors, the signal-processing electronics, and the motion electronics for the half-wave plate movement, is described. Emphasis is placed in the analysis of the polarimeter signals, which permits an in-depth understanding of the performance of the data processing electronics and the role of the various sources of noise in the system. After a brief outline of the basic principle of the measurement, the choice of detectors and their characteristics are described in order to achieve the best performances at the FIR wavelength (λ=118.8 μm) of interest. Various tests, which are described, confirmed the need for a specifically designed pyroelectric detector capable of operating in the hostile magnetic environment near the machine. The processing of the raw polarimeter signals to produce the required sum and difference signals and to convert them into dc signals with 3 ms time constant is presented. These signals are synchronous with a chopper signal on the FIR beam and are subsequently fed to a lock-in amplifier. An accurate analysis of the data processing procedure is described, which helps to clarify the understanding of the output signals that are eventually recorded in the data acquisition system. In particular, various sources of noise, such as thermal noise of the detectors, laser fluctuations, spurious signals at harmonics of the chopper frequency, and phase jitter of the chopper, are evaluated, discussed, and compared with the observed signals. Finally, the control circuitry for the movement of the half-wave plates, both for manual control and for the programmed sequences of zero-search and calibration performed by a PLC control system, is described. Calibration curves obtained

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

    DOE PAGESBeta

    Friend, M.; Parno, D.; Benmokhtar, F.; Camsonne, A.; Dalton, M. M.; Franklin, G. B.; Mamyan, V.; Michaels, R.; Nanda, S.; Nelyubin, V.; et al

    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.

  20. Development of two color laser diagnostics for the ITER poloidal polarimeter

    SciTech Connect

    Kawahata, K.; Akiyama, T.; Tanaka, K.; Nakayama, K.; Okajima, S.

    2010-10-15

    Two color laser diagnostics using terahertz laser sources are under development for a high performance operation of the Large Helical Device and for future fusion devices such as ITER. So far, we have achieved high power laser oscillation lines simultaneously oscillating at 57.2 and 47.7 {mu}m by using a twin optically pumped CH{sub 3}OD laser, and confirmed the original function, compensation of mechanical vibration, of the two color laser interferometer. In this article, application of the two color laser diagnostics to the ITER poloidal polarimeter and recent hardware developments will be described.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  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. 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.

  7. Polarimeter Development for an Electric Dipole Moment Search in a Storage Ring

    SciTech Connect

    Imig, Astrid

    2011-09-23

    The search for a charged particle EDM in a storage ring with the goal of a statistical sensitivity of 10-29 ecenterdotcm/year requires a very sensitive polarimeter. Studies described here have shown that systematic error effects can be handled and corrected to a sensitivity better than the required 10-6 level. The required statistical precision was shown to be attainable using a thick scattering target onto which the stored beam is slowly extracted. Models for geometric and rate systematic error effects describe the results well.

  8. Summary Report of PESP2008 - The Workshop on Polarized Electron Sources and Polarimeters

    SciTech Connect

    Poelker, M.

    2009-08-04

    The Workshop on Polarized Electron Sources and Polarimeters (PESP2008) was hosted by Jefferson Lab October 1-3, 2008, in association with SPIN2008, continuing a tradition since 1983. The workshop was well attended with 84 registrants, 38 oral presentations and 17 posters. The usual topics were covered: DC and RF photoguns, high voltage issues, photocathodes, drive lasers, vacuum and polarimetry. Detailed accounts of each contribution (oral and poster) appear within these Proceedings. This submission summarizes some of the highlights of the workshop.

  9. Imaging molecular structure with Stokes-polarimeter based second harmonic generation microscopy

    NASA Astrophysics Data System (ADS)

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

    2013-02-01

    We analyzed the polarization states of second harmonic generation (SHG) signals from starch granules and type I collagen through a four-channel photon counting based Stokes-polarimeter. The 2D SHG images of samples are reconstructed using various polarization parameters, such as the degree of polarization (DOP), the degree of linear polarization (DOLP), the degree of circular polarization (DOCP), as well as the anisotropy from the acquired Stokes parameters. Furthermore, we have demonstrated that the polarization parameters are changes at different input polarizations and focusing depths.

  10. Ultraviolet Polarimeter for Studying the Aerosol Component in the Earth Atmosphere

    NASA Astrophysics Data System (ADS)

    Nevodovskyi, P. V.; Morozhenko, A. V.; Vidmachenko, A. P.; Geraimchuk, M.; Zbrutskyi, A.; Kureniov, Yu.; Sergunin, V.; Hirniak, Yu.; Ivakhiv, O.

    2013-06-01

    The changes of the weather and climate on the Earth depend on the temperature balance of the planet, i.e., on the flow of radiation coming from the Sun and emitted by the Earth into cosmic space. The changes of transparency coefficients (i.e., optical thickness of the atmosphere) and reflection coefficients (i.e., Earth surface) turn out to be decisive factors disrupting this balance. Variations of the gaseous and aerosol components of the atmosphere make an essential contribution into the changeability of the existing balance. The stratosphere and the ozone layer which protects the Earth from a severe ultraviolet radiation are of special importance in the atmosphere. Stratospheric aerosol plays an important role in the formation of a heat regime and in providing a powerful ozone layer (at the altitude of over 30 km). Spectrophotometer investigations made it possible to obtain certain data on the thickness of aerosols on these altitudes. However, its nature (i.e., a real part of the refraction index) and size distribution functions have not be studied so far. Polarization measurements enable one to most correctly determine these characteristics. The leading astronomical observatory of the National Academy of Sciences of Ukraine in collaboration with the National Technical University of Ukraine "Kyiv Polytechnic Institute" have been carrying out research since 2005 till nowadays on the development of on-board polarimeters for the purpose of studying the stratospheric aerosol from the orbit of Earth satellites [1, 2]. Based on this research, an experimental small sized polarimeter for investigation of a stratospheric aerosol from the orbit of the satellite was created. It is a dot one-channel ultraviolet polarimeter with a rotated polarization element. Glen prism is used as a polarization element which is initiated into motion by a miniature piezoelectric motor. "Sun-blind" low-sized photomultiplier R 1893 made by "Hamamatsu" Co. serves as a radiation receiver that

  11. 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).

  12. 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).

  13. The Kent State {open_quote}{open_quote}2{pi}{close_quote}{close_quote} neutron polarimeter

    SciTech Connect

    Watson, J.W.; Du, Q.; Anderson, B.D.; Baldwin, A.R.; Foster, C.C.; Garcia, L.A.; Hu, X.; Kurmanov, R.; Lamm, D.L.; Madey, R.; Pella, P.J.; Stephenson, E.J.; Wang, Y. |; Wetmore, B.; Zhang, W.

    1995-09-01

    We designed, tested and calibrated a medium-energy neutron polarimeter of a new design, which we call the {open_quote}{open_quote}2{pi}{close_quote}{close_quote} polarimeter because of its symmetric coverage of all 2{pi} of azimuth for double-scattered neutrons. During calibration tests at the IUCF we observed an over all neutron time-of-flight resolution of 360 ps. The measured analyzing power is typically 39{percent} for neutrons of both 130 and 165 MeV for optimum software cuts. The efficiency is typically 0.3{percent}. {copyright} {ital 1995 American Institute of Physics.}

  14. 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).

  15. NASA Jet Noise Research

    NASA Technical Reports Server (NTRS)

    Henderson, Brenda

    2012-01-01

    The presentation highlights jet-noise research conducted in the Subsonic Fixed Wing, Supersonics, and Environmentally Responsible Aviation Projects in the Fundamental Aeronautics Program at NASA. The research efforts discussed include NASA's updated Aircraft NOise Prediction Program (ANOPP2), acoustic-analogy-based prediction tools, jet-surface-interaction studies, plasma-actuator investigations, N+2 Supersonics Validation studies, rectangular-jet experiments, twin-jet experiments, and Hybrid Wind Body (HWB) activities.

  16. Jets of incipient liquids

    NASA Astrophysics Data System (ADS)

    Reshetnikov, A. V.; Mazheiko, N. A.; Skripov, V. P.

    2000-05-01

    Jets of incipient water escaping into the atmosphere through a short channel are photographed. In some experiments. complete disintegration of the jet is observed. The relationship of this phenomenon with intense volume incipience is considered. The role of the Coanda effect upon complete opening of the jet is revealed. Measurement results of the recoil force R of the jets of incipient liquids are presented. Cases of negative thrust caused by the Coanda effect are noted. Generalization of experimental data is proposed.

  17. Prewhirl Jet Model

    NASA Technical Reports Server (NTRS)

    Meng, S. Y.; Jensen, M.; Jackson, E. D.

    1985-01-01

    Simple accurate model of centrifugal or rocket engine pumps provides information necessary to design inducer backflow deflector, backflow eliminator and prewhirl jet in jet mixing zones. Jet design based on this model shows improvement in inducer suction performance and reduced cavitation damage.

  18. Hydrogen production

    NASA Technical Reports Server (NTRS)

    England, C.; Chirivella, J. E.; Fujita, T.; Jeffe, R. E.; Lawson, D.; Manvi, R.

    1975-01-01

    The state of hydrogen production technology is evaluated. Specific areas discussed include: hydrogen production fossil fuels; coal gasification processes; electrolysis of water; thermochemical production of hydrogen; production of hydrogen by solar energy; and biological production of hydrogen. Supply options are considered along with costs of hydrogen production.

  19. Plasma jet ignition device

    DOEpatents

    McIlwain, Michael E.; Grant, Jonathan F.; Golenko, Zsolt; Wittstein, Alan D.

    1985-01-15

    An ignition device of the plasma jet type is disclosed. The device has a cylindrical cavity formed in insulating material with an electrode at one end. The other end of the cylindrical cavity is closed by a metal plate with a small orifice in the center which plate serves as a second electrode. An arc jumping between the first electrode and the orifice plate causes the formation of a highly-ionized plasma in the cavity which is ejected through the orifice into the engine cylinder area to ignite the main fuel mixture. Two improvements are disclosed to enhance the operation of the device and the length of the plasma plume. One improvement is a metal hydride ring which is inserted in the cavity next to the first electrode. During operation, the high temperature in the cavity and the highly excited nature of the plasma breaks down the metal hydride, liberating hydrogen which acts as an additional fuel to help plasma formation. A second improvement consists of a cavity insert containing a plurality of spaced, metal rings. The rings act as secondary spark gap electrodes reducing the voltage needed to maintain the initial arc in the cavity.

  20. 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).

  1. 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.

  2. Systematic and Performance Tests of the Hard X-ray Polarimeter X-Calibur

    NASA Astrophysics Data System (ADS)

    Endsley, Ryan; Beilicke, Matthias; Kislat, Fabian; Krawczynski, Henric; X-Calibur/InFOCuS

    2015-01-01

    X-ray polarimetry has great potential to reveal new astrophysical information about the emission processes of high energy sources such as black hole environments, X-ray binary systems, and active galactic nuclei. Here we present the results and conclusions of systematic and performance measurements of the hard X-ray polarimeter, X-Calibur. Designed to be flown on a balloon-borne X-ray telescope, X-Calibur will achieve unprecedented sensitivity and makes use of the fact that polarized X-rays preferentially Compton-scatter perpendicular to their E-field vector. Extensive laboratory measurements taken at Washington University and the Cornell High-Energy Synchrotron Source (CHESS) indicate that X-Calibur combines a detection efficiency on the order of unity with a high modulation factor of µ ≈ 0.5 averaged over the whole detector assembly, and with values up to µ ≈ 0.7 for select subsections of the polarimeter. Additionally, we are able to suppress background flux by more than two orders of magnitude by utilizing an active shield and scintillator coincidence. Comparing laboratory data with Monte Carlo simulations of both polarized and unpolarized hard X-ray beams illustrate that we have an exceptional understanding of the detector response.

  3. 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.

  4. A double-arm Møller Polarimeter for Jefferson Lab's Hall B

    NASA Astrophysics Data System (ADS)

    Grún, E.; Krúger, H.; Dermott, S.; Fechtig, H.; Graps, A. L.; Zook, H. A.; Gustafson, B. A.; Hamilton, D. P.; Hanner, M. S.; Heck, A.; Horányi, M.; Kissel, J.; Lindbad, B. A.; Linkert, D.; Linkert, G.; Mann, I.; Mcdonnell, J. A. M.; Morfill, G. E.; Polanskey, C.; Schwehm, G.; Srama, R.

    1998-10-01

    We have constructed and commissioned a double-arm Møller polarimeter for the Hall B beamline at the Thomas Jefferson National Accelerator Facility. The polarimeter measures the longitudinal polarization of the 0.8-4.0 GeV electron beam as it enters the experimental hall. The primary components of the apparatus are a target chamber, a pair of quadrupole magnets, and a pair of lead/scintillating-fiber detectors. The target chamber contains two 20 μm-thick permendur foils tilted at ± 20^o with respect to the beam axis. A target polarization of approximately 8% is produced along the beam direction by a 90 G (nominal) magnetic field generated by a pair of Helmholtz coils. The scattered Møller-electron pairs are directed toward the detectors by the quadrupoles. The quadrupoles are are individually tuned--depending on the beam energy--to center the peak of the Møller asymmetry (θ_c.m.=90^o) onto the fixed detectors. The real-to-accidental coincident-detection rate is better than 200:1. The beam polarization can be measured to a 3% relative statistical precision in less than 30 minutes with a relative systematic uncertainty of less than 5%.

  5. A high-contrast imaging polarimeter with a stepped-transmission filter based coronagraph

    NASA Astrophysics Data System (ADS)

    Liu, Cheng-Chao; Ren, De-Qing; Zhu, Yong-Tian; Dou, Jiang-Pei; Guo, Jing

    2016-05-01

    The light reflected from planets is polarized mainly due to Rayleigh scattering, but starlight is normally unpolarized. Thus it provides an approach to enhance the imaging contrast by inducing the imaging polarimetry technique. In this paper, we propose a high-contrast imaging polarimeter that is optimized for the direct imaging of exoplanets, combined with our recently developed stepped-transmission filter based coronagraph. Here we present the design and calibration method of the polarimetry system and the associated test of its high-contrast performance. In this polarimetry system, two liquid crystal variable retarders (LCVRs) act as a polarization modulator, which can extract the polarized signal. We show that our polarimeter can achieve a measurement accuracy of about 0.2% at a visible wavelength (632.8 nm) with linearly polarized light. Finally, the whole system demonstrates that a contrast of 10‑9 at 5λ/D is achievable, which can be used for direct imaging of Jupiter-like planets with a space telescope.

  6. A transmissive x-ray polarimeter design for hard x-ray focusing telescopes

    NASA Astrophysics Data System (ADS)

    Li, Hong; Feng, Hua; Ji, Jianfeng; Deng, Zhi; He, Li; Zeng, Ming; Li, Tenglin; Liu, Yinong; Heng, Peiying; Wu, Qiong; Han, Dong; Dong, Yongwei; Lu, Fangjun; Zhang, Shuangnan

    2015-08-01

    The X-ray Timing and Polarization (XTP) is a mission concept for a future space borne X-ray observatory and is currently selected for early phase study. We present a new design of X-ray polarimeter based on the time projection gas chamber. The polarimeter, placed above the focal plane, has an additional rear window that allows hard X-rays to penetrate (a transmission of nearly 80% at 6 keV) through it and reach the detector on the focal plane. Such a design is to compensate the low detection efficiency of gas detectors, at a low cost of sensitivity, and can maximize the science return of multilayer hard X-ray telescopes without the risk of moving focal plane instruments. The sensitivity in terms of minimum detectable polarization, based on current instrument configuration, is expected to be 3% for a 1mCrab source given an observing time of 105 s. We present preliminary test results, including photoelectron tracks and modulation curves, using a test chamber and polarized X-ray sources in the lab.

  7. X-ray Polarization Measurements with a Micro-pattern Gas Polarimeter

    NASA Technical Reports Server (NTRS)

    Hill, J. E.; Black, J. K.; Deines-Jones, P.; Jahoda, K.; Bellazzini, R.; Brez, A.; Costa, E.; Kaaret, P.; Minuti, M.; Spandre, G.; Swank, J. H.

    2006-01-01

    The benefits of Astrophysical X-ray polarization measurements have been discussed in the literature for decades and with respect to a variety of detectors. Despite this, a dedicated polarimeter for the measurement of Astrophysical sources has not flown since the 1970's, when the definitive measurement of the Crab Nebula was made. More recently, an indirect measurement of the polarization of two gamma-ray bursts has been extracted from BATSE data, re-emphasizing the importance of polarization measurements in constraining a physical model. We describe a sensitive and, and extremely versatile, photoelectric polarimeter using a micro-pattern gas detector, with an 80micron pixel ASIC anode, to image the primary photoelectron track. The detector can be optimized to a preferred energy range between 1 keV and 50 keV. We present measurements of polarized 4.5 keV X-rays and unpolarized 6 keV X-rays obtained with a prototype detector using Carbon Dioxide gas.

  8. Calibration method for division of focal plane polarimeters in the optical and near-infrared regime

    NASA Astrophysics Data System (ADS)

    York, Timothy; Gruev, Viktor

    2011-06-01

    Advances in nanofabrication allow for the creation of metallic nanowires acting as linear polarizers in the visible and near infrared regime. The monolithic integration of silicon detectors and pixelated nanowire metallic polarization filters allows for an efficient realization of high resolution polarization imaging sensors. These silicon sensors, known as division of focal plane polarimeters, capture polarization information of the imaged environment from ~400nm to 1050nm wavelength. The performance of the polarization sensor can be degraded by both irregularities in the fabrication of the nanowires and possible misalignment errors during the final deposition of the optical nanowire filters on the surface of the imaging sensor. In addition, electronic offsets due to the readout circuitry, electronic crosstalk, and optical crosstalk will also negatively affect the quality of the polarization information. Partial compensation for many of these post-fabrication errors can be accomplished through the use of a camera calibration routine. This paper will describe one such routine, and show how its application can increase the quality of measurements in both the degree of linear polarization and angle of polarization in the visible spectrum. The imaging array of the division of focal plane polarimeter is segmented into two by two blocks of superpixels. The calibration method chooses one of the four pixels as a reference, and then a gain and offset for each of the remaining three is computed based on this reference. The output is a calibration matrix for each pixel in the image array.

  9. 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).

  10. Gamma-Ray Burst Polarimeter (GAP) aboard the Small Solar Power Sail Demonstrator IKAROS

    NASA Astrophysics Data System (ADS)

    Yonetoku, Daisuke; Murakami, Toshio; Gunji, Shuichi; Mihara, Tatehiro; Sakashita, Tomonori; Morihara, Yoshiyuki; Kikuchi, Yukihiro; Takahashi, Takuya; Fujimoto, Hirofumi; Toukairin, Noriyuki; Kodama, Yoshiki; Kubo, Shin; Ikaros Demonstration Team

    2011-06-01

    The small solar-power sail demonstrator ``IKAROS'' is a Japanese engineering verification spacecraft launched by the H-IIA rocket on 2010 May 21 at Japan Aerospace Exploration Agency (JAXA) Tanegashima Space Center. IKAROS has a 20 m diameter sail, which is made of a thin polyimide membrane. The sail converts the solar radiation-pressure into the propulsion force of IKAROS, and accelerates the spacecraft. The Gamma-Ray Burst Polarimeter (GAP) aboard IKAROS is the first polarimeter specifically designed to measure the polarization of Gamma-Ray Bursts (GRBs) from space, and will do so in the cruising phase of the IKAROS mission. GAP is a modest detector of 3.8 kg in weight and 17 cm in size with an energy range of between 50-300 keV. The GAP detector is now a member of the interplanetary network (IPN) for determining the GRB direction. The detection principle of gamma-ray polarization is the anisotropy of the Compton scattering. Coincidence between the central plastic Compton scattering medium and discrete CsI detectors distributed around the sides of the plastic defines the Compton-scattering angle, which is expected to show an angular dependence if polarization is present in a given GRB. In this paper, we present the GAP detector and its ground-based and onboard calibrations.

  11. Prototype Spectro-Polarimeter for the India's National Large Solar Telescope

    NASA Astrophysics Data System (ADS)

    Elayavalli Rangarajan, Komandur; Sankarasubramanian, Kasiviswanathan; Srivastava, Nandita; Venkatakrishnan, Parameswaran; Mathew, Shibu; Bayanna, Raja; Hasan, Sirajul; Prabhu, Kesavan

    2013-04-01

    India's National Large Solar Telescope (NLST) of two meter aperture size is proposed to be set up in Ladakh region of Himalayas at a height of around 4300 meters. A high resolution spectrograph along with a polarimeter is planned as one of the backend instruments for NLST. Prototype development of the NLST Spectro-Polarimeter (SP) is proposed to be designed and developed for usage at the back focal plane of the Multi-Application Solar Telescope (MAST) recently installed at the Udaipur Solar Observatory. Design of the prototype SP is discussed in detail along with the scientific goals. The SP is designed to be operated in three wavelengths to observe photospheric and chromospheric layers of the solar atmosphere simultaneously. Vector magnetic fields will be calculated in these layers. High resolution of the designed SP will provide accurate estimates of velocities. Highly resolved polarized line profiles will allow us to obtain the height variation of vector magnetic fields when used along with suitable inversion codes (like SPINOR or SIR).

  12. Transitional Gas Jet Diffusion Flames in Microgravity

    NASA Technical Reports Server (NTRS)

    Agrawal, Ajay K.; Alammar, Khalid; Gollahalli, S. R.; Griffin, DeVon (Technical Monitor)

    2000-01-01

    Drop tower experiments were performed to identify buoyancy effects in transitional hydrogen gas jet diffusion flames. Quantitative rainbow schlieren deflectometry was utilized to optically visualize the flame and to measure oxygen concentration in the laminar portion of the flame. Test conditions consisted of atmospheric pressure flames burning in quiescent air. Fuel from a 0.3mm inside diameter tube injector was issued at jet exit Reynolds numbers (Re) of 1300 to 1700. Helium mole percentage in the fuel was varied from 0 to 40%. Significant effects of buoyancy were observed in near field of the flame even-though the fuel jets were momentum-dominated. Results show an increase of breakpoint length in microgravity. Data suggest that transitional flames in earth-gravity at Re<1300 might become laminar in microgravity.

  13. Aeroacoustics of hot jets

    NASA Astrophysics Data System (ADS)

    Viswanathan, K.

    2004-10-01

    A systematic study has been undertaken to quantify the effect of jet temperature on the noise radiated by subsonic jets. Nozzles of different diameters were tested to uncover the effects of Reynolds number. All the tests were carried out at Boeing's Low Speed Aeroacoustic Facility, with simultaneous measurement of thrust and noise. It is concluded that the change in spectral shape at high jet temperatures, normally attributed to the contribution from dipoles, is due to Reynolds number effects and not dipoles. This effect has not been identified before. A critical value of the Reynolds number that would need to be maintained to avoid the effects associated with low Reynolds number has been estimated to be {˜}400 000. It is well-known that large-scale structures are the dominant generators of noise in the peak radiation direction for high-speed jets. Experimental evidence is presented that shows the spectral shape at angles close to the jet axis from unheated low subsonic jets to be the same as from heated supersonic jets. A possible mechanism for the observed trend is proposed. When a subsonic jet is heated with the Mach number held constant, there is a broadening of the angular sector in which peak radiation occurs. Furthermore, there is a broadening of the spectral peak. Similar trends have been observed at supersonic Mach numbers. The spectral shapes in the forward quadrant and in the near-normal angles from unheated and heated subsonic jets also conform to the universal shape obtained from supersonic jet data. Just as for unheated jets, the peak frequency at angles close to the jet axis is independent of jet velocity as long as the acoustic Mach number is less than unity. The extensive database generated in the current test programme is intended to provide test cases with high-quality data that could be used for the evaluation of theoretical/semi-theoretical jet noise prediction methodologies.

  14. Theory of laminar viscous jets

    NASA Astrophysics Data System (ADS)

    Martynenko, O. G.; Korovkin, V. N.; Sokovishin, Iu. A.

    Results of recent theoretical studies of laminar jet flows of a viscous incompressible fluid are reviewed. In particular, attention is given to plane, fan-shaped, axisymmetric, and swirling jet flows; jet flows behind bodies; and slipstream jet flows. The discussion also covers dissipation of mechanical energy in jet flows, jet flows with a zero excess momentum, and asymptotic series expansions in the theory of jet flows.

  15. Jet Substructure Without Trees

    SciTech Connect

    Jankowiak, Martin; Larkoski, Andrew J.; /SLAC /Stanford U., ITP

    2011-08-19

    We present an alternative approach to identifying and characterizing jet substructure. An angular correlation function is introduced that can be used to extract angular and mass scales within a jet without reference to a clustering algorithm. This procedure gives rise to a number of useful jet observables. As an application, we construct a top quark tagging algorithm that is competitive with existing methods. In preparation for the LHC, the past several years have seen extensive work on various aspects of collider searches. With the excellent resolution of the ATLAS and CMS detectors as a catalyst, one area that has undergone significant development is jet substructure physics. The use of jet substructure techniques, which probe the fine-grained details of how energy is distributed in jets, has two broad goals. First, measuring more than just the bulk properties of jets allows for additional probes of QCD. For example, jet substructure measurements can be compared against precision perturbative QCD calculations or used to tune Monte Carlo event generators. Second, jet substructure allows for additional handles in event discrimination. These handles could play an important role at the LHC in discriminating between signal and background events in a wide variety of particle searches. For example, Monte Carlo studies indicate that jet substructure techniques allow for efficient reconstruction of boosted heavy objects such as the W{sup {+-}} and Z{sup 0} gauge bosons, the top quark, and the Higgs boson.

  16. 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

  17. 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

  18. Axial jet mixing of ethanol in cylindrical containers during weightlessness

    NASA Technical Reports Server (NTRS)

    Aydelott, J. C.

    1979-01-01

    An experimental program was conducted to examine the liquid flow patterns that result from the axial jet mixing of ethanol in 10-centimeter-diameter cylindrical tanks in weightlessness. A convex hemispherically ended tank and two Centaur liquid-hydrogen-tank models were used for the study. Four distinct liquid flow patterns were observed to be a function of the tank geometry, the liquid-jet velocity, the volume of liquid in the tank, and the location of the tube from which the liquid jet exited.

  19. Jets from young stars

    NASA Astrophysics Data System (ADS)

    Bally, John

    2007-10-01

    Most stars produce spectacular jets during their formation. There are thousands of young stars within 500 pc of the Sun and many power jets. Thus protostellar jets may be the most common type of collimated astrophysical outflow. Shocks powered by outflows excite many emission lines, exhibit a rich variety of structure, and motions with velocities ranging from 50 to over 500 km s-1. Due to their relative proximity, proper motions and structural changes can be observed in less than a year. I review the general properties of protostellar jets, summarize some results from recent narrow-band imaging surveys of entire clouds, discuss irradiated jets, and end with some comments concerning outflows from high-mass young stellar objects. Protostellar outflows are ideal laboratories for the exploration of the jet physics.

  20. Relativistic Jets in Collapsars

    NASA Astrophysics Data System (ADS)

    Zhang, Weiqun; Woosley, S. E.; MacFadyen, A. I.

    2003-04-01

    We examine the propagation of two-dimensional relativistic jets through the stellar progenitor in the collapsar model for gamma-ray bursts. In agreement with previous studies, we find that the jet is collimated by its passage. Moreover, interaction of the jet with the star causes mixing that sporadically decelerates the jet, leading to a highly variable Lorentz factor. The jet that finally emerges has a moderate Lorentz factor, but a very large internal energy loading. In a second series of calculations we follow the emergence of such enegy-loaded jets from the star. For the initial conditions chosen, conversion of the remaining internal energy gives a terminal Lorentz factor of approximately 150. Implications of our calculations for GRB light curves, the luminosity-variability relation, and the GRB-supernova association are discussed.

  1. What ignites optical jets?

    SciTech Connect

    Sebastian Jester

    2002-12-23

    The properties of radio galaxies and quasars with and without optical or X-ray jets are compared. The majority of jets from which high-frequency emission has been detected so far (13 with optical emission, 11 with X-rays, 13 with both) are associated with the most powerful radio sources at any given redshift. It is found that optical/X-ray jet sources are more strongly beamed than the average population of extragalactic radio sources. This suggests that the detection or non-detection of optical emission from jets has so far been dominated by surface brightness selection effects, not by jet physics. It implies that optical jets are much more common than is currently appreciated.

  2. Expected performance of a hard X-ray polarimeter (POLAR) by Monte Carlo simulation

    NASA Astrophysics Data System (ADS)

    Xiong, Shaolin; Produit, Nicolas; Wu, Bobing

    2009-07-01

    Polarization measurements of the prompt emission in gamma-ray bursts (GRBs) can provide diagnostic information for understanding the nature of the central engine. POLAR is a compact polarimeter dedicated to the polarization measurement of GRBs between 50 and 300 keV and is scheduled to be launched aboard the Chinese Space Laboratory around the year 2012. A preliminary Monte Carlo simulation has been accomplished to model the expected performance of POLAR while a prototype of POLAR is being constructed. The modulation factor, efficiency and effective area, background rates and minimum detectable polarization (MDP) were calculated for different detector configurations and trigger strategies. With the optimized detector configuration and trigger strategy and the total weight constraint of less than 30 kg, the primary science goal to determine whether most GRBs are strongly polarized can be achieved, and about 9 GRBs/yr can be detected with an MDP<10% for the conservative detector configuration.

  3. 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.

  4. Commissioning of an integral-field spectro-polarimeter for PMAS

    NASA Astrophysics Data System (ADS)

    Lemke, Ulrike; Kelz, Andreas; Bauer, Svend M.; Hahn, Thomas; Popow, Emil; Roth, Martin M.

    2008-07-01

    During 2007, a new polarimetric observing mode was added to the existing integral-field spectrograph PMAS. Initially, this instrumental upgrade is aimed to measure the linear polarization states and to determine the three Stokes parameters I, Q and U. The PMAS instrument offers an integral-field of view of up to 256 square arcseconds, while the spectrograph covers a wavelength region from 340 to 900 nm. The paper presents the opto-mechanical design of the polarimetric unit, summarizes calibration and test results and describes the first data taken during commissioning at the Calar Alto observatory. Given the range of applications and the large parameter space (two spatial coordinates, one wavelength dimension, plus polarimetric information), the realization of the PMAS 2D-Spectro-Polarimeter provides a unique capability for night-time astrophysical observations, such as the study of scattering processes or magnetic fields for a range of astronomical targets.

  5. 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°.

  6. Research in solar physics: Some techniques for analyzing data from the ultraviolet spectrometer and polarimeter

    NASA Technical Reports Server (NTRS)

    Henze, W., Jr.

    1984-01-01

    Useful information for certain aspects of the analysis of data obtained by the Ultraviolet Spectrometer and Polarimeter (UVSP) on the Solar Maximum Mission (SMM) are contained. The meaning of the UVSPCO-ordinate system and the SMM roll, pitch, and yaw are described and the process for overlaying UVSP images is explained. The various computer programs that calculate the line of sight component of the SMM spacecraft velocity from the spacecraft to the Sun is described. The spacecraft velocity is used to correct or interpret the signal observed in USVP dopplergrams. A method of using the spacecraft velocity to calibrate UVSP dopplergrams and magnetograms, i.e., determine the width of the observed emission line is applied. The UVSP polarization analysis procedures are described and the expressions for the statistical uncertainties in various quantities obtained from UVSP measurements are given.

  7. 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.

    2016-03-01

    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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Passive multispectral imaging polarimeter for remote atmospheric and surface studies: design based on optical coatings.

    PubMed

    Pellicori, Samuel F; Burke, Elliot

    2016-02-20

    The passive imaging polarimeter architecture is based on optical coatings and thereby avoids the complexities of current systems that use rotating polarizers, phase-modulating retarders, and birefringent elements. Coatings on stationary elements separate spectral regions and their polarized components to simultaneously produce images of the Stokes linear polarization intensities in fields of view (FOVs) ≥30°. Wavelength and FOV coverages are limited only by the telescope and relay optics employed. The images are collected in identical spectral passbands that can extend from UV to shortwave IR. An example relevant to remote sensing in the 360-900 nm range is given. An on-board calibration and stability monitor is included. PMID:26906581

  16. 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.

  17. 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.

  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. 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.

  20. 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

  1. Properties of gluon jets

    SciTech Connect

    Sugano, K.

    1986-09-01

    The properties of gluon jets are reviewed from an experimental point of view. The measured characteristics are compared to theoretical expectations. Although neither data nor models for the gluon jets are in the mature stage, there are remarkable agreements and also intriguing disagreements between experiment and theory. Since much interesting data have begun to emerge from various experiments and the properties of gluon jets are deeply rooted in the basic structure of non-Abelian gauge theory, the study of gluon jets casts further light on our understanding of QCD. Finally, the future prospects are discussed.

  2. Perspectives on jet noise

    NASA Technical Reports Server (NTRS)

    Ribner, H. S.

    1981-01-01

    Jet noise is a byproduct of turbulence. Until recently turbulence was assumed to be known statistically, and jet noise was computed therefrom. As a result of new findings though on the behavior of vortices and instability waves, a more integrated view of the problem has been accepted lately. After presenting a simple view of jet noise, the paper attempts to resolve the apparent differences between Lighthill's and Lilley's interpretations of mean-flow shear, and examines a number of ad hoc approaches to jet noise suppression.

  3. Interpretation of extragalactic jets

    SciTech Connect

    Norman, M.L.

    1985-01-01

    The nature of extragalatic radio jets is modeled. The basic hypothesis of these models is that extragalatic jets are outflows of matter which can be described within the framework of fluid dynamics and that the outflows are essentially continuous. The discussion is limited to the interpretation of large-scale (i.e., kiloparsec-scale) jets. The central problem is to infer the physical parameters of the jets from observed distributions of total and polarized intensity and angle of polarization as a function of frequency. 60 refs., 6 figs.

  4. Hydrogen sensor

    DOEpatents

    Duan, Yixiang; Jia, Quanxi; Cao, Wenqing

    2010-11-23

    A hydrogen sensor for detecting/quantitating hydrogen and hydrogen isotopes includes a sampling line and a microplasma generator that excites hydrogen from a gas sample and produces light emission from excited hydrogen. A power supply provides power to the microplasma generator, and a spectrometer generates an emission spectrum from the light emission. A programmable computer is adapted for determining whether or not the gas sample includes hydrogen, and for quantitating the amount of hydrogen and/or hydrogen isotopes are present in the gas sample.

  5. Measurements of Hydrogen

    NASA Astrophysics Data System (ADS)

    Ashburn, John Robert

    1990-01-01

    The H(n = 3) density matrices for hydrogen atoms resulting from 20 to 150 keV protons on helium were measured. The technique consisted of applying electric fields in the collision region to Stark mix the field-free eigenstates of H atoms and measuring the Stokes parameters of the emitted Balmer-alpha radiation as a function of the electric field. The n = 3 density matrix with 14 independent parameters associated with the newly formed hydrogen atoms could be fit to the measured Balmer- alpha signals via multivariate regression. The theoretical signal responses used for the fit were determined by fully modeling the collision region and calculating the transition amplitudes of the Stark-mixed hydrogenic states. Significant improvements in the measuring apparatus and in the analysis associated with the fit of the density matrix to the optical signals have reduced systematic errors which were present in the previous investigation. The improvements include a modified optical system, which was automated and calibrated with a well defined viewing region. The performance of four different polarimeters was investigated with the optical system. Also, the background subtraction technique was improved with the addition of an automated gas handling system. Improvements were also implemented in the design of the electrodes which were used for the applied electric fields. Nonuniformities which were present in the electric field were determined by a numerical model and were incorporated into the analysis. The analysis which determined the theoretical signal responses was extensively modified and it was found that H(n = 4) cascade was the most critical limiting factor for the accuracy of the results. An agreement analysis which utilized Hotelling's T^2 statistic determined that smaller systematic errors do remain and that the results are less reproducible at the lower energies studied. However, the results were improved by combining and analyzing the axial and transverse field data

  6. Conversion of crop seed oils to jet fuel and associated methods

    DOEpatents

    Ginosar, Daniel M.; Petkovic, Lucia M.; Thompson, David N.

    2010-05-18

    Aspects of the invention include methods to produce jet fuel from biological oil sources. The method may be comprised of two steps: hydrocracking and reforming. The process may be self-sufficient in heat and hydrogen.

  7. Determination of electron beam polarization using electron detector in Compton polarimeter with less than 1% statistical and systematic uncertainty

    NASA Astrophysics Data System (ADS)

    Narayan, Amrendra

    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 (~1GeV) electron beam polarization with a Compton electron detector. We have demonstrated that diamond based micro-strip detectors can be used for tracking in a

  8. 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

  9. Hydrogenation apparatus

    DOEpatents

    Friedman, Joseph [Encino, CA; Oberg, Carl L [Canoga Park, CA; Russell, Larry H [Agoura, CA

    1981-01-01

    Hydrogenation reaction apparatus comprising a housing having walls which define a reaction zone and conduits for introducing streams of hydrogen and oxygen into the reaction zone, the oxygen being introduced into a central portion of the hydrogen stream to maintain a boundary layer of hydrogen along the walls of the reaction zone. A portion of the hydrogen and all of the oxygen react to produce a heated gas stream having a temperature within the range of from 1100.degree. to 1900.degree. C., while the boundary layer of hydrogen maintains the wall temperature at a substantially lower temperature. The heated gas stream is introduced into a hydrogenation reaction zone and provides the source of heat and hydrogen for a hydrogenation reaction. There also is provided means for quenching the products of the hydrogenation reaction. The present invention is particularly suitable for the hydrogenation of low-value solid carbonaceous materials to provide high yields of more valuable liquid and gaseous products.

  10. Hydrogen-air mixing evaluation in reciprocating engines

    SciTech Connect

    Dodge, L; Naegeli, D

    1994-06-01

    This report presents the results of a computational study of fuel-air mixing in a hydrogen jet using a spark-ignited, hydrogen-fueled engine. The computational results were compared with experimental measurement being conducted at the Musashi Institute of Technology in Tokyo, Japan. The hydrogen-air mixing work was directed at understanding the extreme sensitivity of ignition to spark plug location and spark timing in direct-injected, hydrogen-fueled engines.

  11. Comparison of the single/multi transverse jets under the influence of shock wave in supersonic crossflow

    NASA Astrophysics Data System (ADS)

    Barzegar Gerdroodbary, M.; Rahimi Takami, M.; Heidari, H. R.; Fallah, Keivan; Ganji, D. D.

    2016-06-01

    In this study, the effects of the shock wave on sonic transverse hydrogen through single and multi-jets for supersonic combustion were investigated numerically. This study presents the fundamental flow physics of the interaction between fuel jets (single or multi array) and incident shock waves into a Mach 4.0 crossflow. Parametric studies were conducted on the performance of the shock wave by using the RANS equations with Menter's Shear Stress Transport turbulence model. In a parametric study, both the streamwise spacing and jet-to-freestream total pressure ratio are varied. For all downstream mixing, the associated flow behavior was found to be a direct result of both the type of injection (single/Multi jet) and interactions between shock waves and injectors. According to the results, shock wave reduces the maximum concentration of the hydrogen jet more than 20% in both single and multi jet. Furthermore, a significant increase (approximately 40%) occurs in the mixing of the hydrogen jet at downstream when shock generator is presented in the multi jet with PR=0.27. Moreover, hydrogen-air mixing rate extends in streamwise direction as the jet space increases. Thus, an enhanced mixing zone occurs in the in far downstream of the jet and the shock wave.

  12. Modeling leaks from liquid hydrogen storage systems.

    SciTech Connect

    Winters, William Stanley, Jr.

    2009-01-01

    This report documents a series of models for describing intended and unintended discharges from liquid hydrogen storage systems. Typically these systems store hydrogen in the saturated state at approximately five to ten atmospheres. Some of models discussed here are equilibrium-based models that make use of the NIST thermodynamic models to specify the states of multiphase hydrogen and air-hydrogen mixtures. Two types of discharges are considered: slow leaks where hydrogen enters the ambient at atmospheric pressure and fast leaks where the hydrogen flow is usually choked and expands into the ambient through an underexpanded jet. In order to avoid the complexities of supersonic flow, a single Mach disk model is proposed for fast leaks that are choked. The velocity and state of hydrogen downstream of the Mach disk leads to a more tractable subsonic boundary condition. However, the hydrogen temperature exiting all leaks (fast or slow, from saturated liquid or saturated vapor) is approximately 20.4 K. At these temperatures, any entrained air would likely condense or even freeze leading to an air-hydrogen mixture that cannot be characterized by the REFPROP subroutines. For this reason a plug flow entrainment model is proposed to treat a short zone of initial entrainment and heating. The model predicts the quantity of entrained air required to bring the air-hydrogen mixture to a temperature of approximately 65 K at one atmosphere. At this temperature the mixture can be treated as a mixture of ideal gases and is much more amenable to modeling with Gaussian entrainment models and CFD codes. A Gaussian entrainment model is formulated to predict the trajectory and properties of a cold hydrogen jet leaking into ambient air. The model shows that similarity between two jets depends on the densimetric Froude number, density ratio and initial hydrogen concentration.

  13. A sensitivity-enhanced optical heterodyne polarimeter for the measurement of optical rotation angle of chiral media

    NASA Astrophysics Data System (ADS)

    Tsai, Ying C.; Wu, Chien M.

    2004-09-01

    A novel heterodyne polarimeter is designed to measure the concentration of chiral media. Optical common-path for the interference of the TE and TM waves, after a polarizer, is set up in our system to reduce noises from the environment. A phase-variable waveplate is placed behind the sample to enhance the phase signal change of rotation of polarization introduced by the sample itself. This enhancement can be excess two orders in amplitude when the retardation of the phase-variable plate is set close to 180 degree. With this polarimeter, the measurement of optical rotation angle with high sensitivity of 6.5×10-4 degree experimentally can be achieved when phase retardation of the phase-variable waveplate is 178.5 degree. We expect that, by further improvement, it can be applied in noninvasive blood glucose concentration monitoring for diabetics in the future.

  14. 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).

  15. 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.

  16. Large size GEM for Super Bigbite Spectrometer (SBS) polarimeter for Hall A 12GeV program at JLab

    DOE PAGESBeta

    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 asmore » the preliminary results on performances from tests carried out in our detector lab and with test beams at (Fermilab).« less

  17. Jet Lag in Athletes

    PubMed Central

    Lee, Aaron; Galvez, Juan Carlos

    2012-01-01

    Context: Prolonged transmeridian air travel can impart a physical and emotional burden on athletes in jet lag and travel fatigue. Jet lag may negatively affect the performance of athletes. Study Type: Descriptive review. Evidence Acquisition: A Medline search for articles relating to jet lag was performed (1990-present), as was a search relating to jet lag and athletes (1983-January, 2012). The results were reviewed for relevance. Eighty-nine sources were included in this descriptive review. Results: Behavioral strategies are recommended over pharmacological strategies when traveling with athletes; pharmacological aides may be used on an individual basis. Strategic sleeping, timed exposure to bright light, and the use of melatonin are encouraged. Conclusions: There is strong evidence that mood and cognition are adversely affected by jet lag. Some measures of individual and team performance are adversely affected as well. PMID:23016089

  18. Description of Jet Breakup

    NASA Technical Reports Server (NTRS)

    Papageorgiou, Demetrios T.

    1996-01-01

    In this article we review recent results on the breakup of cylindrical jets of a Newtonian fluid. Capillary forces provide the main driving mechanism and our interest is in the description of the flow as the jet pinches to form drops. The approach is to describe such topological singularities by constructing local (in time and space) similarity solutions from the governing equations. This is described for breakup according to the Euler, Stokes or Navier-Stokes equations. It is found that slender jet theories can be applied when viscosity is present, but for inviscid jets the local shape of the jet at breakup is most likely of a non-slender geometry. Systems of one-dimensional models of the governing equations are solved numerically in order to illustrate these differences.

  19. Multiple jet study

    NASA Technical Reports Server (NTRS)

    Walker, R. E.; Kors, D. L.

    1973-01-01

    Test data is presented which allows determination of jet penetration and mixing of multiple cold air jets into a ducted subsonic heated mainstream flow. Jet-to-mainstream momentum flux ratios ranged from 6 to 60. Temperature profile data is presented at various duct locations up to 24 orifice diameters downstream of the plane of jet injection. Except for two configurations, all geometries investigated had a single row of constant diameter orifices located transverse to the main flow direction. Orifice size and spacing between orifices were varied. Both of these were found to have a significant effect on jet penetration and mixing. The best mixing of the hot and cold streams was achieved with duct height.

  20. Jet physics at CDF

    SciTech Connect

    Melese, P.

    1997-05-01

    We present high E{sub T} jet measurements from CDF at the Fermilab Tevatron Collider. The incfilusive jet cross section at {radical}s = 1800 GeV with {approximately} 5 times more data is compared to the published CDF results, preliminary D0 results, and next-to-leading order QCD predictions. The {summation}E{sub T} cross section is also compared to QCD predictions and the dijet angular distribution is used to place a limit on quark compositeness. The inclusive jet cross section at {radical}s = 630 GeV is compared with that at 1800 GeV to test the QCD predictions for the scaling of jet cross sections with {radical}s. Finally, we present momentum distributions of charged particles in jets and compare them to Modified Leading Log Approximation predictions.

  1. 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.

  2. Beam Test of a Prototype Phoswich Detector Assembly forthe PoGOLite Astronomical Soft Gamma-ray Polarimeter

    SciTech Connect

    Kanai, Y.; Ueno, M.; Kataoka, J.; Arimoto, M.; Kawai, N.; Yamamoto, K.; Mizuno, T.; Fukazawa, Y.; Kiss, M.; Ylinen, T.; Bettolo, C.Marini; Carlson, P.; P.Chen d, B.Craig d, T.Kamae d, G.Madejski d, J.S.T.Ng; Rogers, R.; Tajima, H.; Thurston, T.S.; Saito, Y.; Takahashi, T. Gunji, S.; Bjornsson, C-I.; Larsson, S.; /Stockholm U. /Ecole Polytechnique /KEK, Tsukuba

    2007-01-17

    We report about the beam test on a prototype of the balloon-based astronomical soft gamma-ray polarimeter, PoGOLite (Polarized Gamma-ray Observer--Light Version) conducted at KEK Photon Factory, a synchrotron radiation facility in Japan. The synchrotron beam was set at 30, 50, and 70 keV and its polarization was monitored by a calibrated polarimeter. The goal of the experiment was to validate the flight design of the polarimeter. PoGOLite is designed to measure polarization by detecting a Compton scattering and the subsequent photo-absorption in an array of 217 well-type phoswich detector cells (PDCs). The test setup included a first flight model PDC and a front-end electronics to select and reconstruct valid Compton scattering events. The experiment has verified that the flight PDC can detect recoil electrons and select valid Compton scattering events down to 30 keV from background. The measure azimuthal modulations (34.4 %, 35.8 % and 37.2 % at 30, 50, and 70 keV, respectively) agreed within 10% (relative) with the predictions by Geant4 implemented with dependence on the initial and final photon polarizations.

  3. 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

  4. Jet Boost Pumps For The Space Shuttle Main Engine

    NASA Technical Reports Server (NTRS)

    Meng, Sen Y.

    1991-01-01

    Brief report proposes use of jet boost pumps in conjunction with main pumps supplying liquid hydrogen and liquid oxygen to main engine of Space Shuttle. Main part of pump has no moving parts. Benefits include increased reliability, simplified ducts, and decreased weight.

  5. Jet Noise Suppression

    NASA Technical Reports Server (NTRS)

    Gliebe, P. R.; Brausch, J. F.; Majjigi, R. K.; Lee, R.

    1991-01-01

    The objectives of this chapter are to review and summarize the jet noise suppression technology, to provide a physical and theoretical model to explain the measured jet noise suppression characteristics of different concepts, and to provide a set of guidelines for evolving jet noise suppression designs. The underlying principle for all jet noise suppression devices is to enhance rapid mixing (i.e., diffusion) of the jet plume by geometric and aerothermodynamic means. In the case of supersonic jets, the shock-cell broadband noise reduction is effectively accomplished by the elimination or mitigation of the shock-cell structure. So far, the diffusion concepts have predominantly concentrated on jet momentum and energy (kinetic and thermal) diffusion, in that order, and have yielded better noise reduction than the simple conical nozzles. A critical technology issue that needs resolution is the effect of flight on the noise suppression potential of mechanical suppressor nozzles. A more thorough investigation of this mechanism is necessary for the successful development and design of an acceptable noise suppression device for future high-speed civil transports.

  6. Two-dimensional solar spectropolarimetry with the KIS/IAA Visible Imaging Polarimeter

    NASA Astrophysics Data System (ADS)

    Beck, C.; Bellot Rubio, L. R.; Kentischer, T. J.; Tritschler, A.; Del Toro Iniesta, J. C.

    2010-09-01

    Context. Spectropolarimetry at high spatial and spectral resolution is a basic tool to characterize the magnetic properties of the solar atmosphere. Aims: We introduce the KIS/IAA Visible Imaging Polarimeter (VIP), a new post-focus instrument that upgrades the TESOS spectrometer at the German Vacuum Tower Telescope (VTT) into a full vector polarimeter. VIP is a collaboration between the Kiepenheuer Institut für Sonnenphysik (KIS) and the Instituto de Astrofísica de Andalucía (IAA-CSIC). Methods: We describe the optical setup of VIP, the data acquisition procedure, and the calibration of the spectropolarimetric measurements. We show examples of data taken between 2005 and 2008 to illustrate the potential of the instrument. Results: VIP is capable of measuring the four Stokes profiles of spectral lines in the range from 420 to 700 nm with a spatial resolution better than 0farcs5. Lines can be sampled at 40 wavelength positions in 60 s, achieving a noise level of about 2 × 10-3 with exposure times of 300 ms and pixel sizes of 0farcs17 × 0farcs17 (2 × 2 binning). The polarization modulation is stable over periods of a few days, ensuring high polarimetric accuracy. The excellent spectral resolution of TESOS allows the use of sophisticated data analysis techniques such as Stokes inversions. One of the first scientific results of VIP presented here is that the ribbon-like magnetic structures of the network are associated with a distinct pattern of net circular polarization away from disk center. Conclusions: VIP performs spectropolarimetric measurements of solar magnetic fields at a spatial resolution that is only slightly worse than that of the Hinode spectropolarimeter, while providing a 2D field field of view and the possibility to observe up to four spectral regions sequentially with high cadence. VIP can be used as a stand-alone instrument or in combination with other spectropolarimeters and imaging systems of the VTT for extended wavelength coverage.

  7. 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

  8. 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?

  9. 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

  10. The Identification of Mitogen Responding Subpopulations of Human Lymphocytes by Flow Polarimeter Fluorescence Measurements.

    NASA Astrophysics Data System (ADS)

    Chan, Sandra Lynn

    I have developed a method to identify the mitogen responding subpopulation of human peripheral blood lymphocytes. This method employs a flow polarimeter to measure the distribution of the intensity and the polarization of intracellular fluorescein fluorescence in suspensions of mononuclear cells isolated on density gradients from the peripheral blood of donors. I have used the change in the fluorescence of cells exposed to the mitogens PHA and Con A to identify the responding cells and to quantitate this number. I have found that for most donors, the responding cells constitute about 20-40% of the lymphocyte population. The percent of responding cells decreases to zero in patients with acute lymphocytic leukemia (2 patients) and chronic lymphocyte leukemia (10 patients). For a variety of patients with other types of cancer, the responding fraction was not significantly different from healthy controls. Moreover, the number of responding cells does not appear to be age dependent in the age range of 20-80 years. I also found that the change in fluorescence polarization correlated strongly with changes in fluorescence intensity induced by mitogens--the number of responding cells, therefore can be estimated either from the intensity or polarization distributions. The shapes of fluorescence distributions depend strongly on a number of variables including the composition and density of the lymphocyte isolating medium, the mitogen and dye concentrations, the length of incubation with mitogen or dye, and the potassium, calcium, and magnesium concentrations in the medium. In the case of fluorescein, I have worked out a methodology that allows a consistent estimate of the responding lymphocyte number. I have also investigated the use of the dye carbocyanine for the same purpose. This dye presumably identifies the mitogen responding lymphocytes on the basis of changes in membrane potential. The results with carbocyanine were found to depend on a number of variables and I could

  11. 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

  12. 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

  13. 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

  14. Characterization of Super-Cooled Liquid Water Clouds Using the Research Scanning Polarimeter Measurements

    NASA Astrophysics Data System (ADS)

    Alexandrov, M. D.; Cairns, B.; van Diedenhoven, B.; Wasilewski, A. P.; Ackerman, A. S.

    2014-12-01

    Super-cooled liquid water (SCW) clouds, where liquid droplets exist at temperatures below 0oC, impact both the radiative budget and the development of precipitation. They also present an aviation hazard due to their role in aircraft icing. The two 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) provided a unique opportunity to observe SCW clouds from the high-altitude airborne platform of NASA's ER-2 aircraft. We present an analysis of the measurements made by the Research Scanning Polarimeter (RSP) during these experiments. This instrument measures both polarized and total reflectance in 9 spectral channels with central wavelengths of 410, 470, 555, 670, 865, 960, 1590, 1880 and 2250 nm. The RSP is a scanning sensor taking samples at 0.8o intervals within 60o from nadir in both forward and backward directions. This unique high angular resolution allows for characterization of liquid water droplet size using the rainbow structure observed in the polarized reflectances in the scattering angle range between 135o and 165o for every pixel independently. Simple parametric fitting algorithms applied to the polarized reflectance provide 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 us to retrieve the droplet size distribution itself. The latter is important in the case of SCW clouds, which often have complex spatial and microphysical structure. For example the measurements made on 22 September 2013 during SEAC4RS indicate a cloud that alternates between being in glaciated and liquid phases, with super-cooled liquid drops at altitudes as high as 10 km, which

  15. Angular Scaling In Jets

    SciTech Connect

    Jankowiak, Martin; Larkoski, Andrew J.; /SLAC

    2012-02-17

    We introduce a jet shape observable defined for an ensemble of jets in terms of two-particle angular correlations and a resolution parameter R. This quantity is infrared and collinear safe and can be interpreted as a scaling exponent for the angular distribution of mass inside the jet. For small R it is close to the value 2 as a consequence of the approximately scale invariant QCD dynamics. For large R it is sensitive to non-perturbative effects. We describe the use of this correlation function for tests of QCD, for studying underlying event and pile-up effects, and for tuning Monte Carlo event generators.

  16. Design of the cryogenic hydrogen release laboratory

    SciTech Connect

    Hecht, Ethan S.; Zimmerman, Mark D.; LaFleur, Angela Christine; Ciotti, Michael

    2015-09-01

    A cooperative research and development agreement was made between Linde, LLC and Sandia to develop a plan for modifying the Turbulent Combustion Laboratory (TCL) with the necessary infrastructure to produce a cold (near liquid temperature) hydrogen jet. A three-stage heat exchanger will be used to cool gaseous hydrogen using liquid nitrogen, gaseous helium, and liquid helium. A cryogenic line from the heat exchanger into the lab will allow high-fidelity diagnostics already in place in the lab to be applied to cold hydrogen jets. Data from these experiments will be used to develop and validate models that inform codes and standards which specify protection criteria for unintended releases from liquid hydrogen storage, transport, and delivery infrastructure.

  17. Jet Feedback on the Interstellar Medium of the Radio Galaxy 3C 293

    NASA Astrophysics Data System (ADS)

    Lanz, Lauranne; Ogle, Patrick M.; Appleton, Philip N.; Emonts, Bjorn; Evans, Daniel A.

    2014-06-01

    We present a 70 ks Chandra observation of the radio galaxy 3C 293. This galaxy belongs to the class of molecular hydrogen emission galaxies (MOHEGs) that have very luminous emission from warm molecular hydrogen. In the case of radio galaxies, the molecular gas appears to be heated by jet-driven ISM turbulence. 3C 293 contains 3.7 x 10^9 solar masses of shock-heated, 100 K molecular hydrogen in an extended 10 kpc scale region. With Chandra, we observe emission from the jets both within the host galaxy and outside of the galaxy, along the 100 kpc radio jets. Some of the soft X-rays are coincident with the radio hotspots, but one X-ray emitting feature is anti-coincident with the radio emission. We model the X-ray spectra of the nucleus, the inner jets, and the X-ray features along the extended radio jets. Both the nucleus and the inner jets show evidence of 10^7 K shock-heated gas. The kinetic power of the jets is more than sufficient to heat the X-ray emitting gas, which serves as a reservoir of thermal and turbulent energy to maintain the molecular hydrogen emission over a time scale of 10^7 years.

  18. Experimental characterization of a transition from collisionless to collisional interaction between head-on-merging supersonic plasma jets

    SciTech Connect

    Moser, Auna L. Hsu, Scott C.

    2015-05-15

    We present results from experiments on the head-on merging of two supersonic plasma jets in an initially collisionless regime for the counter-streaming ions. The plasma jets are of either an argon/impurity or hydrogen/impurity mixture and are produced by pulsed-power-driven railguns. Based on time- and space-resolved fast-imaging, multi-chord interferometry, and survey-spectroscopy measurements of the overlapping region between the merging jets, we observe that the jets initially interpenetrate, consistent with calculated inter-jet ion collision lengths, which are long. As the jets interpenetrate, a rising mean-charge state causes a rapid decrease in the inter-jet ion collision length. Finally, the interaction becomes collisional and the jets stagnate, eventually producing structures consistent with collisional shocks. These experimental observations can aid in the validation of plasma collisionality and ionization models for plasmas with complex equations of state.

  19. Fast Quenching For Hydrogen-Embrittlement Tests

    NASA Technical Reports Server (NTRS)

    Petri, Mark J.; Burkhart, Richard L.; Koncel, Joseph F.

    1990-01-01

    Apparatus exposes hot metal specimens in hydrogen atmospheres to sudden cooling. Heater surrounds pressure vessel initially. On command, heater slides downward on track, exposing vessel. Spray bar falls over vessel and directs high-pressure jets of cold water at it. Developed to evaluate susceptibilities of specimens to embrittlement by hydrogen. Cools specimens by 1,050 degrees F (580 degrees C) in 160 seconds.

  20. Hydrogen and Gaseous Fuel Safety and Toxicity

    SciTech Connect

    Lee C. Cadwallader; J. Sephen Herring

    2007-06-01

    Non-traditional motor fuels are receiving increased attention and use. This paper examines the safety of three alternative gaseous fuels plus gasoline and the advantages and disadvantages of each. The gaseous fuels are hydrogen, methane (natural gas), and propane. Qualitatively, the overall risks of the four fuels should be close. Gasoline is the most toxic. For small leaks, hydrogen has the highest ignition probability and the gaseous fuels have the highest risk of a burning jet or cloud.

  1. Dilution jet mixing program

    NASA Technical Reports Server (NTRS)

    Srinivasan, R.; Coleman, E.; Johnson, K.

    1984-01-01

    Parametric tests were conducted to quantify the mixing of opposed rows of jets (two-sided injection) in a confined cross flow. Results show that jet penetrations for two sided injections are less than that for single-sided injections, but the jet spreading rates are faster for a given momentum ratio and orifice plate. Flow area convergence generally enhances mixing. Mixing characteristics with asymmetric and symmetric convergence are similar. For constant momentum ratio, the optimum S/H(0) with in-line injections is one half the optimum value for single sided injections. For staggered injections, the optimum S/H(0) is twice the optimum value for single-sided injection. The correlations developed predicted the temperature distributions within first order accuracy and provide a useful tool for predicting jet trajectory and temperature profiles in the dilution zone with two-sided injections.

  2. Jet lag prevention

    MedlinePlus

    ... your internal clock before you travel. While in flight: DO NOT sleep unless it matches the bedtime ... decrease jet lag. If you will be in flight during the bedtime of your destination, take some ...

  3. Counterflowing Jet Subsystem Design

    NASA Technical Reports Server (NTRS)

    Farr, Rebecca; Daso, Endwell; Pritchett, Victor; Wang, Ten-See

    2010-01-01

    A counterflowing jet design (a spacecraft and trans-atmospheric subsystem) employs centrally located, supersonic cold gas jets on the face of the vehicle, ejecting into the oncoming free stream. Depending on the supersonic free-stream conditions and the ejected mass flow rate of the counterflowing jets, the bow shock of the vehicle is moved upstream, further away from the vehicle. This results in an increasing shock standoff distance of the bow shock with a progressively weaker shock. At a critical jet mass flow rate, the bow shock becomes so weak that it is transformed into a series of compression waves spread out in a much wider region, thus significantly modifying the flow that wets the outer surfaces, with an attendant reduction in wave and skin friction drag and aerothermal loads.

  4. A cryogenic half-wave plate polarimeter using a superconducting magnetic bearing

    NASA Astrophysics Data System (ADS)

    Klein, Jeff; Aboobaker, Asad; Ade, Peter; Aubin, François; Baccigalupi, Carlo; Bao, Chaoyun; Borrill, Julian; Chapman, Daniel; Didier, Joy; Dobbs, Matt; Gold, Benjamin; Grainger, Will; Hanany, Shaul; Hubmayr, Johannes; Hillbrand, Seth; Grain, Julien; Jaffe, Andrew; Johnson, Bradley; Jones, Terry; Kisner, Theodore; Korotkov, Andrei; Leach, Sam; Lee, Adrian; Levinson, Lorne; Limon, Michele; MacDermid, Kevin; Matsumura, Tomotake; Miller, Amber; Milligan, Michael; Pascale, Enzo; Polsgrove, Daniel; Ponthieu, Nicolas; Raach, Kate; Reichborn-Kjennerud, Britt; Sagiv, Ilan; Stompor, Radek; Tran, Huan; Tristram, Matthieu; Tucker, Gregory S.; Yadav, Amit; Zaldarriaga, Matias; Zilic, Kyle

    2011-10-01

    We present the design and measured performance of the superconducting magnetic bearing (SMB) that was used successfully as the rotation mechanism in the half-wave plate polarimeter of the E and B Experiment (EBEX) during its North American test flight. EBEX is a NASA-supported balloon-borne experiment that is designed to measure the polarization of the cosmic microwave background. In this implementation the half-wave plate is mounted to the rotor of an SMB that is operating at the sink temperature of 4 K. We demonstrate robust, remote operation on a balloon-borne payload, with angular encoding accuracy of 0.01°. We find rotational speed variation to be 0.2% RMS. We measure vibrational modes and find them to be consistent with a simple SMB model. We search for but do not find magnetic field interference in the detectors and readout. We set an upper limit of 3% of the receiver noise level after 5 minutes of integration on such interference. At 2 Hz rotation we measure a power dissipation of 56 mW. If this power dissipation is reduced, such an SMB implementation is a candidate for low-noise space applications because of the absence of stick-slip friction and low wear.

  5. 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.

  6. 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.

    2016-03-01

    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.

  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. 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.

  9. Study of retro reflector array for the polarimeter-interferometer system on EAST Tokamak

    NASA Astrophysics Data System (ADS)

    Lan, T.; Wang, S. X.; Liu, H. Q.; Liu, J.; Jie, Y. X.; Zou, Z. Y.; Li, W. M.; Gao, X.; Qin, H.

    2015-12-01

    In this paper, we experimentally verify the feasibility of replacing individual retro reflectors (RRs) with retro reflector array (RRA) in EAST POlarimeter/INTerferometer (POINT) system, by considering mode transformation and power wastage. Being exposed to plasma environment directly, RRs have risks of deformation, erosion and deposition. RRA is preferable because it can be installed within a smaller space and provide a gap of several centimeters for the shutter design. This protective structure can reduce the cost of device maintenance and bring down system errors. According to Helmholtz-Kirchhoff integral theorem, the optimized incident diameter for the RRA, constituted by seven hexagonal RR cells, is 40 mm in POINT system. The corresponding bench tests are carried out by measuring the propagation properties of reflected beams by plane RRA for perpendicular incidence and reflected beams by terrace RRA for oblique incidence. The experimental results illustrate that RRA can be satisfactorily applied in POINT system at the optimized incident diameter. In view of the energy wastage caused by plasma film coating, it is found that RRA has more advantages for diagnostics using shorter wavelengths, such as the case in ITER.

  10. Fundus depolarization imaging with GDx VCC scanning laser polarimeter and depolarization characteristics of normal eyes

    NASA Astrophysics Data System (ADS)

    Zhou, Qienyuan; Leder, Henry A.; Lo, Barrick P.; Reed, Geradus C.; Knighton, Robert W.; Cousins, Scott W.

    2009-02-01

    GDx VCC is a confocal scanning laser polarimeter (SLP) developed to assess the retinal nerve fiber layer (RNFL) of the eye based on measurement of the phase retardation in the backscattered light from the fundus. In addition to the phase retardation measurement, a depolarization measurement is readily available from the same image series. We hypothesize that the depolarized light in the GDx signal consists of backscattering from the retinal pigment epithelium (RPE) and the RPE-Bruch's membrane junction, and further, that subRPE deposits contribute to the depolarized backscattered light in proportion to their thickness. Therefore, a quantitative macular depolarization map will provide information about both spatial distribution and heterogeneity of the RPE structure and deposit thickness. Ultimately we predict that depolarization mapping will significantly increase the positive predictive power to identify early dry AMD eyes. In this paper, depolarization measurements in normal eyes and age related changes are reported. Data collection was performed at the Duke University Eye Center. A commercial GDx VCC system was modified with a central fixation target and, instead of depolarized light intensity images, normalized depolarization images were derived and saved in the database. Macular depolarization was observed to increase with age in normal eyes at a rate of 0.27%/yr.

  11. Heterodyne double-channel polarimeter for mapping birefringence and thickness of flat glass panels

    SciTech Connect

    Protopopov, Vladimir V.; Cho, Sunghoon; Kim, Kwangso; Lee, Sukwon; Kim, Hyuk; Kim, Daesuk

    2006-05-15

    A new cross-polarized heterodyne optical technique is developed for two-dimensional (2D) simultaneous mapping of both birefringence and thickness variations in large flat glass panels commonly used in liquid-crystal displays (LCDs). Weak depolarization of a linearly polarized probe beam due to glass birefringence is detected by means of heterodyne mixing of the two cross-polarized and frequency shifted waves generated by Zeeman-type laser. Amplitude variations of the transmitted laser beam due to interference of the partial waves reflected from the both sides of a sample provide information about glass thickness. Measurements are being performed at the intermediate frequency of 2.3 MHz, providing several orders of magnitude higher speed of data acquisition with respect to traditional polarimeters. That high speed of measurements makes it possible to perform quality assessment of LCD glass panels not only in few randomly chosen points as it was in common practice before but to obtain entire 2D maps of both birefringence and thickness variations with millimeter scale spatial resolution. The medium-scale prototype of the LCD glass inspection system is developed and tested. Design and performance of the prototype are described.

  12. Optimal configurations of full-Stokes polarimeter with immunity to both Poisson and Gaussian noise

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

    For a full-Stokes polarimeter (FSP), generally there are two types of noise, signal-dependent Poisson shot noise and signal-independent additive Gaussian noise, which will degrade the signal-to-noise ratio on the measured Stokes parameters. The relation between the immunity to Gaussian noise and the condition of the measurement matrix has been widely studied in the recent literature. In this paper, we present a new merit function and use it to achieve optimal configurations with immunity to both types of noise. The numerical results show that, for the FSP consisting of variable retarders followed by a fixed polarizer, the four measurement channels immune to these two types of noise can be optimally composed by a 102.2° retardance with a pair of azimuths ±71.9° and a 142.1° retardance with a pair of azimuths ±34.95°, or by two quarter-wave plates with four pairs of azimuths (±70.15°, ±87.84°) and (±42.82°, ±19.14°). The tolerances of the retardances or azimuths in the optimized configurations are evaluated for practical manufacturing, assembling and alignment.

  13. 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.

  14. Fine-pitch and thick-foil gas electron multipliers for cosmic x-ray polarimeters

    NASA Astrophysics Data System (ADS)

    Tamagawa, Toru; Hayato, Asami; Yamaguchi, Yorito; Hamagaki, Hideki; Hashimoto, Shigehira; Inuzuka, Masahide; Miyasaka, Hiromasa; Sakurai, Ikuya; Tokanai, Fuyuki; Makishima, Kazuo

    2006-06-01

    We have produced various gas electron multiplier foils (GEMs) by using laser etching technique for cosmic X-ray polarimeters. The finest structure GEM we have fabricated has 30 μm-diameter holes on a 50 μm-pitch. The effective gain of the GEM reaches around 5000 at the voltage of 570 V between electrodes. The gain is slightly higher than that of the CERN standard GEM with 70 μm-diameter holes on a 140 μm-pitch. We have fabricated GEMs with thickness of 100 μm which has two times thicker than the standard GEM. The effective gain of the thick-foil GEM is 104 at the applied voltage of 350 V per 50 μm of thickness. The gain is about two orders higher than that of the standard GEM. The remarkable characteristic of the thick-foil GEM is that the effective gain at the beginning of micro-discharge is quite improved. For fabricating the thick-foil GEMs, we have employed new material, liquid crystal polymer (LCP) which has little moisture absorption rate, as an insulator layer instead of polyimide. One of the thick-foil GEM we have fabricated has 8 μm copper layer in the middle of the 100 μm-thick insulator layer. The metal layer in the middle of the foil works as a field-shaper in the multiplication channels, though it slightly decreases the effective gain.

  15. Determination of azimuthal anchoring strength in twisted nematic liquid crystal cells using heterodyne polarimeter.

    PubMed

    Yu, Tsung-Chih; Lo, Yu-Lung; Huang, Rei-Rong

    2010-09-27

    Two external-field-free methods are presented for measuring the azimuthal anchoring strength in twisted nematic liquid crystal (TNLC) cells. For asymmetrical TNLC samples, the twist angle is derived from the phase of the detected signal in a phase-sensitive heterodyne polarimeter and is then used to calculate the weak anchoring strength directly. The measurement resolution which is found to be about 0.01 μJ/m(2) makes the present method sensitive enough for the LC-based bio-sensing application. Using the proposed method, the weak azimuthal anchoring strength of a composite liquid crystal mixture (40% LCT-061153 + 60% MJO-42761) in contact with a plasma-alignment layer is found to be 7.19 μJ/m(2). For symmetrical TNLC samples, the liquid crystals are injected into a wedge cell, and the two-dimensional distributions of the twist angle and cell gap are extracted from the detected phase distribution using a genetic algorithm (GA). The azimuthal anchoring strength is then obtained by applying a fitting technique to the twist angle vs. cell gap curve. Utilizing the proposed approach, it is shown that the strong anchoring strength between a rubbed polyimide (PI) alignment layer and E7 liquid crystal is around 160 μJ/m(2) while that between a rubbed PI alignment layer and MLC-7023 liquid crystal is approximately 32 μJ/m(2). PMID:20941014

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

    NASA Astrophysics Data System (ADS)

    Orsi, S.; Polar Collaboration

    2011-02-01

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

  17. Modeling precision and accuracy of a LWIR microgrid array imaging polarimeter

    NASA Astrophysics Data System (ADS)

    Boger, James K.; Tyo, J. Scott; Ratliff, Bradley M.; Fetrow, Matthew P.; Black, Wiley T.; Kumar, Rakesh

    2005-08-01

    Long-wave infrared (LWIR) imaging is a prominent and useful technique for remote sensing applications. Moreover, polarization imaging has been shown to provide additional information about the imaged scene. However, polarization estimation requires that multiple measurements be made of each observed scene point under optically different conditions. This challenging measurement strategy makes the polarization estimates prone to error. The sources of this error differ depending upon the type of measurement scheme used. In this paper, we examine one particular measurement scheme, namely, a simultaneous multiple-measurement imaging polarimeter (SIP) using a microgrid polarizer array. The imager is composed of a microgrid polarizer masking a LWIR HgCdTe focal plane array (operating at 8.3-9.3 μm), and is able to make simultaneous modulated scene measurements. In this paper we present an analytical model that is used to predict the performance of the system in order to help interpret real results. This model is radiometrically accurate and accounts for the temperature of the camera system optics, spatial nonuniformity and drift, optical resolution and other sources of noise. This model is then used in simulation to validate it against laboratory measurements. The precision and accuracy of the SIP instrument is then studied.

  18. Prospects for Studying Interstellar Magnetic Fields with a Far-Infrared Polarimeter for SAFIR

    NASA Technical Reports Server (NTRS)

    Dowell, C. Darren; Chuss, D. T.; Dotson, J. L.

    2008-01-01

    Polarimetry at mid-infrared through millimeter wavelengths using airborne and ground-based telescopes has revealed magnetic structures in dense molecular clouds in the interstellar medium, primarily in regions of star formation. Furthermore, spectropolarimetry has offered clues about the composition of the dust grains and the mechanism by which they are aligned with respect to the local magnetic field. The sensitivity of the observations to date has been limited by the emission from the atmosphere and warm telescopes. A factor of 1000 in sensitivity can be gained by using instead a cold space telescope. With 5 arcminute resolution, Planck will make the first submillimeter polarization survey of the full Galaxy early in the next decade. We discuss the science case for and basic design of a far-infrared polarimeter on the SAFIR space telescope, which offers resolution in the few arcsecond range and wavelength selection of cold and warm dust components. Key science themes include the formation and evolution of molecular clouds in nearby spiral galaxies, the magnetic structure of the Galactic center, and interstellar turbulence.

  19. 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.

  20. Infrared Stokes Spectro-Polarimeter at the National Astronomical Observatory of Japan

    NASA Astrophysics Data System (ADS)

    Hanaoka, Y.; Sakurai, T.; Shinoda, K.; Noguchi, M.; Miyashita, M.; Fukuda, T.; Suzuki, I.; Hagino, M.; Arai, T.; Yamasaki, T.; Takeyama, N.

    2011-04-01

    We are now constructing an infrared spectro-polarimeter for the Solar Flare Telescope of NAOJ. It observes the full Sun in two wavelength bands, one near 1.56 μm for highly Zeeman-sensitive spectral lines of Fe I and the other near 10830 Å for He I and Si I lines. The instrument records full Stokes profiles, and a Stokes inversion process will give information on the strength and orientation of the magnetic field vector for both of the photosphere and the chromosphere. The infrared detector we are using is an InGaAs camera manufactured by a Belgian company Xenics. Its format is 640×512 pixels and its read-out speed is 90 frames s-1. The solar disk will be covered by two swaths (the northern and southern hemispheres) of 640 pixels each. The final magnetic maps will be made of 1200×1200 pixels with a pixel size of 1.8 arcsec. Now we are operating regular observations and generate full-disk, full-Stokes maps (a few maps per day). Our ultimate goal is to derive the distribution of magnetic helicity over the whole surface of the Sun, not only in sunspots and active regions.

  1. 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.

  2. Underwater partial polarization signatures from the shallow water real-time imaging polarimeter (SHRIMP)

    NASA Astrophysics Data System (ADS)

    Taylor, James S., Jr.; Davis, P. S.; Wolff, Lawrence B.

    2003-09-01

    Research has shown that naturally occurring light outdoors and underwater is partially linearly polarized. The polarized components can be combined to form an image that describes the polarization of the light in the scene. This image is known as the degree of linear polarization (DOLP) image or partial polarization image. These naturally occurring polarization signatures can provide a diver or an unmanned underwater vehicle (UUV) with more information to detect, classify, and identify threats such as obstacles and/or mines in the shallow water environment. The SHallow water Real-time IMaging Polarimeter (SHRIMP), recently developed under sponsorship of Dr. Tom Swean at the Office of Naval Research (Code 321OE), can measure underwater partial polarization imagery. This sensor is a passive, three-channel device that simultaneously measures the three components of the Stokes vector needed to determine the partial linear polarization of the scene. The testing of this sensor has been completed and the data has been analyzed. This paper presents performance results from the field-testing and quantifies the gain provided by the partial polarization signature of targets in the Very Shallow Water (VSW) and Surf Zone (SZ) regions.

  3. HX-POL-A Balloon-Borne Hard X-Ray Polarimeter

    NASA Technical Reports Server (NTRS)

    Krawczynski, H.; Garson, A., III; Martin, J.; Li, Q.; Beilicke, M.; Dowkontt, P.; Lee, K.; Wulf, E.; Kurfess, J.; Novikova, E. I.; De Geronimo, G.; Baring, M. G.; Harding, A. K.; Grindlay, J.; Hong, J. S.

    2009-01-01

    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. Index Terms Gamma-ray astronomy, gamma-ray astronomy detectors, polarization, semiconductor radiation detectors, X-ray astronomy, X-ray astronomy detectors.

  4. Simulation and Laboratory results of the Hard X-ray Polarimeter: X-Calibur

    NASA Astrophysics Data System (ADS)

    Guo, Qingzhen; Beilicke, M.; Kislat, F.; Krawczynski, H.

    2014-01-01

    X-ray polarimetry promises to give qualitatively new information about high-energy sources, such as binary black hole (BH) systems, Microquasars, active galactic nuclei (AGN), GRBs, etc. We designed, built and tested a hard X-ray polarimeter 'X-Calibur' to be flown in the focal plane of the InFOCuS grazing incidence hard X-ray telescope in 2014. X-Calibur combines a low-Z Compton scatterer with a CZT detector assembly to measure the polarization of 20- 80 keV X-rays making use of the fact that polarized photons Compton scatter preferentially perpendicular to the E field orientation. X-Calibur achieves a high detection efficiency of order unity. We optimized of the design of the instrument based on Monte Carlo simulations of polarized and unpolarized X-ray beams and of the most important background components. We have calibrated and tested X-Calibur extensively in the laboratory at Washington University and at the Cornell High-Energy Synchrotron Source (CHESS). Measurements using the highly polarized synchrotron beam at CHESS confirm the polarization sensitivity of the instrument. In this talk we report on the optimization of the design of the instrument based on Monte Carlo simulations, as well as results of laboratory calibration measurements characterizing the performance of the instrument.

  5. MSFC Reviews Wisconsin Ultraviolet Photo-Polarimeter Experiment (WUPPE) Data During STS-35 Mission

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The primary objective of the STS-35 mission was round the clock observation of the celestial sphere in ultraviolet and X-Ray astronomy with the Astro-1 observatory which consisted of four telescopes: the Hopkins Ultraviolet Telescope (HUT); the Wisconsin Ultraviolet Photo-Polarimeter Experiment (WUPPE); the Ultraviolet Imaging Telescope (UIT); and the Broad Band X-Ray Telescope (BBXRT). The Huntsville Operations Support Center (HOSC) Spacelab Payload Operations Control Center (SL POCC) at the Marshall Space Flight Center (MSFC) was the air/ground communication channel used between the astronauts and ground control teams during the Spacelab missions. Teams of controllers and researchers directed on-orbit science operations, sent commands to the spacecraft, received data from experiments aboard the Space Shuttle, adjusted mission schedules to take advantage of unexpected science opportunities or unexpected results, and worked with crew members to resolve problems with their experiments. Due to loss of data used for pointing and operating the ultraviolet telescopes, MSFC ground teams were forced to aim the telescopes with fine tuning by the flight crew. This photo captures the activity of WUPPE data review at the Science Operations Area during the mission.

  6. 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.

  7. Airborne multiangle spectropolarimetric imager (AirMSPI) observations over California during NASA's polarimeter definition experiment (PODEX)

    NASA Astrophysics Data System (ADS)

    Diner, David J.; Garay, Michael J.; Kalashnikova, Olga V.; Rheingans, Brian E.; Geier, Sven; Bull, Michael A.; Jovanovic, Veljko M.; Xu, Feng; Bruegge, Carol J.; Davis, Ab; Crabtree, Karlton; Chipman, Russell A.

    2013-09-01

    The Airborne Multiangle SpectroPolarimetric Imager (AirMSPI) is an ultraviolet/visible/near-infrared pushbroom camera mounted on a single-axis gimbal to acquire multiangle imagery over a +/-67° along-track range. The instrument flies aboard NASA's high-altitude ER-2 aircraft, and acquires Earth imagery with ~10 m spatial resolution across an 11- km wide swath. Radiance data are obtained in eight spectral bands (355, 380, 445, 470, 555, 660, 865, 935 nm). Dual photoelastic modulators (PEMs), achromatic quarter-wave plates, and wire-grid polarizers also enable imagery of the linear polarization Stokes components Q and U at 470, 660, and 865 nm. During January-February 2013, AirMSPI data were acquired over California as part of NASA's Polarimeter Definition Experiment (PODEX), a field campaign designed to refine requirements for the future Aerosol-Cloud-Ecosystem (ACE) satellite mission. Observations of aerosols, low- and mid-level cloud fields, cirrus, aircraft contrails, and clear skies were obtained over the San Joaquin Valley and the Pacific Ocean during PODEX. Example radiance and polarization images are presented to illustrate some of the instrument's capabilities.

  8. 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.

  9. 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.

  10. The POLAR gamma-ray burst polarimeter onboard the Chinese Spacelab

    NASA Astrophysics Data System (ADS)

    Orsi, Silvio; Cadoux, Franck; Leluc, Catherine; Paniccia, Mercedes; Pohl, Martin; Rapin, Divic; Gauvin, Neal; Produit, Nicolas; Bao, Tianwei; Chai, Junying; Dong, Yongwei; Kong, Minnan; Lu, Li; Liu, Jiangtao; Liu, Xin; Shi, Haoli; Sun, Jianchao; Wang, Ruijie; Wen, Xing; Wu, Bobing; Xiao, Hualin; Xu, Hanhui; Zhang, Li; Zhang, Laiyu; Zhang, Shuangnan; Zhang, Yongjie; Britvich, Ilia; Hajdas, Wojtek; Marcinkowski, Radoslaw; Rybka, Dominik K.; Batsch, Tadeusz; Rutczynska, Aleksandra; Szabelski, Jacek; Zwolinska, Ania

    2014-07-01

    POLAR is a joint European-Chinese experiment aimed at a precise measurement of hard X-ray polarization (50-500 keV) of the prompt emission of Gamma-Ray Bursts. The main aim is a better understanding of the geometry of astrophysical sources and of the X-ray emission mechanisms. POLAR is a compact Compton polarimeter characterized by a large modulation factor, effective area, and field of view. It consists of 1600 low-Z plastic scintillator bars read out by 25 at-panel multi-anode photomultipliers. The incoming X-rays undergo Compton scattering in the bars and produce a modulation pattern; experiments with polarized synchrotron radiation and GEANT4 Monte Carlo simulations have shown that the polarization degree and angle can be retrieved from this pattern with the accuracy necessary for identifying the GRB mechanism. The flight model of POLAR is currently under construction in Geneva. The POLAR instrument will be placed onboard the Chinese spacelab TG-2, scheduled for launch in low Earth orbit in 2015. The main milestones of the space qualification campaign will be described in the paper.

  11. 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.

  12. Performance Characterization of the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) CCD Cameras

    NASA Astrophysics Data System (ADS)

    Joiner, R. K.; Kobayashi, K.; Winebarger, A. R.; Champey, P. R.

    2014-12-01

    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 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. 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.

  14. Characterization of cloud microphysical parameters using airborne measurements by the research scanning polarimeter

    NASA Astrophysics Data System (ADS)

    Alexandrov, Mikhail D.; Cairns, Brian; Mishchenko, Michael I.; Ackerman, Andrew S.; Emde, Claudia

    2013-05-01

    We present the retrievals of cloud droplet size distribution parameters (effective radius and variance) from the Research Scanning Polarimeter (RSP) measurements made during the recent field campaign Development and Evaluation of satellite Validation Tools by Experimenters (DEVOTE, 2011). 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 wavelengths ranging from 410 to 2250 nm. For cloud droplet size retrievals we utilize the polarized reflectances in the scattering range between 135° and 165° where they exhibit the rainbow, the shape of which is determined mainly by single-scattering properties of the cloud particles. Two different retrieval methods were used: standard fitting of the observations with a model based on pre-assumed gamma distribution shape, and a novel non-parametric technique Rainbow Fourier Transform (RFT), which does not require any a priori assumptions about the droplet size distribution. The RSP measurements over cumulus clouds also allow for estimation of their geometry (cloud length, top and base heights), which, combined with the droplet size, can provide further insight into cloud processes.

  15. Jets in hadronic reactions

    SciTech Connect

    Paige, F.E.

    1983-01-01

    Recent experimental data on the properties of jets in hadronic reactions are reviewed and compared with theoretical expectations. Jets are clearly established as the dominant process for high E/sub T/ events in hadronic reactions. The cross section and the other properties of these events are in qualitative and even semiquantitative agreement with expectations based on perturbative QCD. However, we can not yet make precise tests of QCD, primarily because there are substantial uncertainties in the theoretical calculations. 45 references. (WHK)

  16. Radiation from Relativistic Jets

    NASA Technical Reports Server (NTRS)

    Nishikawa, K.-I.; Mizuno, Y.; Hardee, P.; Sol, H.; Medvedev, M.; Zhang, B.; Nordlund, A.; Frederiksen, J. T.; Fishman, G. J.; Preece, R.

    2008-01-01

    Nonthermal radiation observed from astrophysical systems containing relativistic jets and shocks, e.g., gamma-ray bursts (GRBs), active galactic nuclei (AGNs), and Galactic microquasar systems usually have power-law emission spectra. Recent PIC simulations of relativistic electron-ion (electron-positron) jets injected into a stationary medium show that particle acceleration occurs within the downstream jet. In the presence of relativistic jets, instabilities such as the Buneman instability, other two-streaming instability, and the Weibel (filamentation) instability create collisionless shocks, which are responsible for particle (electron, positron, and ion) acceleration. The simulation results show that the Weibel instability is responsible for generating and amplifying highly nonuniform, small-scale magnetic fields. These magnetic fields contribute to the electron's transverse deflection behind the jet head. The 'jitter' radiation from deflected electrons in small-scale magnetic fields has different properties than synchrotron radiation which is calculated in a uniform magnetic field. This jitter radiation, a case of diffusive synchrotron radiation, may be important to understand the complex time evolution and/or spectral structure in gamma-ray bursts, relativistic jets, and supernova remnants.

  17. Hydrogen Production

    SciTech Connect

    2014-09-01

    This 2-page fact sheet provides a brief introduction to hydrogen production technologies. Intended for a non-technical audience, it explains how different resources and processes can be used to produce hydrogen. It includes an overview of research goals as well as “quick facts” about hydrogen energy resources and production technologies.

  18. Hydrogenation apparatus

    DOEpatents

    Friedman, J.; Oberg, C. L.; Russell, L. H.

    1981-06-23

    Hydrogenation reaction apparatus is described comprising a housing having walls which define a reaction zone and conduits for introducing streams of hydrogen and oxygen into the reaction zone, the oxygen being introduced into a central portion of the hydrogen stream to maintain a boundary layer of hydrogen along the walls of the reaction zone. A portion of the hydrogen and all of the oxygen react to produce a heated gas stream having a temperature within the range of from 1,100 to 1,900 C, while the boundary layer of hydrogen maintains the wall temperature at a substantially lower temperature. The heated gas stream is introduced into a hydrogenation reaction zone and provides the source of heat and hydrogen for a hydrogenation reaction. There also is provided means for quenching the products of the hydrogenation reaction. The present invention is particularly suitable for the hydrogenation of low-value solid carbonaceous materials to provide high yields of more valuable liquid and gaseous products. 2 figs.

  19. Neutron streaming along ducts and labyrinths at the JET biological shielding: Effect of concrete composition

    NASA Astrophysics Data System (ADS)

    Vasilopoulou, T.; Stamatelatos, I. E.; Batistoni, P.; Conroy, S.; Obryk, B.; Popovichev, S.; Syme, D. B.

    2015-11-01

    Experiments and Monte Carlo simulations were performed at the Joint European Torus (JET) in order to validate the computational tools and methods applied for neutron streaming calculations through penetrations in the JET Hall biological shielding. In the present work the sensitivity of the simulations on the hydrogen and boron content in concrete shielding was investigated. MCNP code was used to simulate neutron streaming along the JET Hall personnel entrance labyrinth for deuterium-deuterium and deuterium-tritium plasma sources for different concrete wall compositions. Neutron fluence and ambient dose equivalent along the labyrinth were calculated. Simulation results for the "as built" JET concrete composition were compared against measurements performed using thermoluminescence detectors. This study contributes to the optimization of the radiation shielding of JET and, furthermore, provides information from JET experience that may assist in optimizing and validating the radiation shielding design methodology used in its successor fusion devices ITER and DEMO.

  20. RoboPol: Unveiling the Physics of Blazar Jets from Skinakas

    NASA Astrophysics Data System (ADS)

    Pavlidou, V.

    2016-06-01

    Blazars are powered by relativistic jets and radiate exclusively through extreme, nonthermal particle interactions, energized by accretion onto supermassive black holes. Despite intensive observational and theoretical efforts over the last four decades, the details of blazar astrophysics remain elusive. The launch of NASA's Fermi Gammaray Space Telescope in 2008 provided an unprecedented opportunity for the systematic study of blazar jets and has prompted large-scale blazar monitoring efforts across wavelengths. In such a multi-wavelength campaign, a novel effect was discovered: fast changes in the optical polarization during gamma-ray flares. Optical emission from blazars is significantly polarized and the polarization probes the magnetic field structure in the jet. For this reason, such polarization rotations reveal important information about the evolution of disturbances responsible for blazar flares. The RoboPol program for the polarimetric monitoring of statistically complete samples of blazars was developed in 2013 to systematically study this class of events. RoboPol is a collaboration between the University of Crete, Caltech, the Max-Planck Institute for Radio Astronomy, the Inter-University Centre for Astronomy and Astrophysics in India, and the Nicolaus Copernicus University in Poland. Using a novel polarimeter operating at the 1.3m telescope of the Skinakas Observatory in Crete, it has succeeded in its 3 years of operation in taking optopolarimetric rotations of blazars from novelty status to a well-studied phenomenon that can be used to answer long-standing questions in our theoretical understanding of jets. We review the RoboPol program and its most important results in the classification of the optopolarimetric properties of blazars, the statistical properties of polarization rotations, and their relation to gamma-ray activity in blazar jets.