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Sample records for polarization caliop instrument

  1. Subtropical and Polar Cirrus Clouds Characterized by Ground-Based Lidars and CALIPSO/CALIOP Observations

    Directory of Open Access Journals (Sweden)

    Córdoba-Jabonero Carmen

    2016-01-01

    Full Text Available Cirrus clouds are product of weather processes, and then their occurrence and macrophysical/optical properties can vary significantly over different regions of the world. Lidars can provide height-resolved measurements with a relatively good both vertical and temporal resolutions, making them the most suitable instrumentation for high-cloud observations. The aim of this work is to show the potential of lidar observations on Cirrus clouds detection in combination with a recently proposed methodology to retrieve the Cirrus clouds macrophysical and optical features. In this sense, a few case studies of cirrus clouds observed at both subtropical and polar latitudes are examined and compared to CALIPSO/CALIOP observations. Lidar measurements are carried out in two stations: the Metropolitan city of Sao Paulo (MSP, Brazil, 23.3°S 46.4°W, located at subtropical latitudes, and the Belgrano II base (BEL, Argentina, 78ºS 35ºW in the Antarctic continent. Optical (COD-cloud optical depth and LR-Lidar Ratio and macrophysical (top/base heights and thickness properties of both the subtropical and polar cirrus clouds are reported. In general, subtropical Cirrus clouds present lower LR values and are found at higher altitudes than those detected at polar latitudes. In general, Cirrus clouds are detected at similar altitudes by CALIOP. However, a poor agreement is achieved in the LR retrieved between ground-based lidars and space-borne CALIOP measurements, likely due to the use of a fixed (or low-variable LR value in CALIOP inversion procedures.

  2. Spatial and seasonal distribution of Arctic aerosols observed by the CALIOP satellite instrument (2006–2012

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    M. Di Pierro

    2013-07-01

    Full Text Available We use retrievals of aerosol extinction from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP onboard the CALIPSO satellite to examine the vertical, horizontal and temporal variability of tropospheric Arctic aerosols during the period 2006–2012. We develop an empirical method that takes into account the difference in sensitivity between daytime and nighttime retrievals over the Arctic. Comparisons of the retrieved aerosol extinction to in situ measurements at Barrow (Alaska and Alert (Canada show that CALIOP reproduces the observed seasonal cycle and magnitude of surface aerosols to within 25 %. In the free troposphere, we find that daytime CALIOP retrievals will only detect the strongest aerosol haze events, as demonstrated by a comparison to aircraft measurements obtained during NASA's ARCTAS mission during April 2008. This leads to a systematic underestimate of the column aerosol optical depth by a factor of 2–10. However, when the CALIOP sensitivity threshold is applied to aircraft observations, we find that CALIOP reproduces in situ observations to within 20% and captures the vertical profile of extinction over the Alaskan Arctic. Comparisons with the ground-based high spectral resolution lidar (HSRL at Eureka, Canada, show that CALIOP and HSRL capture the evolution of the aerosol backscatter vertical distribution from winter to spring, but a quantitative comparison is inconclusive as the retrieved HSRL backscatter appears to overestimate in situ observations by a factor of 2 at all altitudes. In the High Arctic (>70° N near the surface (−1, followed by a sharp decline and a minimum in May–September (1–4 Mm−1, thus providing the first pan-Arctic view of Arctic haze seasonality. The European and Asian Arctic sectors display the highest wintertime extinctions, while the Atlantic sector is the cleanest. Over the Low Arctic (60–70° N near the surface, CALIOP extinctions reach a maximum over land in summer due to

  3. A-train CALIOP and MLS observations of early winter Antarctic polar stratospheric clouds and nitric acid in 2008

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    A. Lambert

    2012-03-01

    Full Text Available A-train Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP and Microwave Limb Sounder (MLS observations are used to investigate the development of polar stratospheric clouds (PSCs and the gas-phase nitric acid distribution in the early 2008 Antarctic winter. Observational evidence of gravity-wave activity is provided by Atmospheric Infrared Sounder (AIRS radiances and infrared spectroscopic detection of nitric acid trihydrate (NAT in PSCs is obtained from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS. Goddard Earth Observing System Data Assimilation System (GEOS-5 DAS analyses are used to derive Lagrangian trajectories and to determine temperature-time histories of air parcels. We use CALIOP backscatter and depolarization measurements to classify PSCs and the MLS measurements to determine the corresponding gas-phase HNO3 as a function of temperature. For liquid PSCs the uptake of HNO3 follows the theoretical equilibrium curve for supercooled ternary solutions (STS, but at temperatures about 1 K lower as determined from GEOS-5. In the presence of solid phase PSCs, above the ice frost-point, the HNO3 depletion occurs over a wider range of temperatures (+2 to −7 K distributed about the NAT equilibrium curve. Rapid gas-phase HNO3 depletion is first seen by MLS from from 23–25 May 2008, consisting of a decrease in the volume mixing ratio from 14 ppbv (parts per billion by volume to 7 ppbv on the 46–32 hPa (hectopascal pressure levels and accompanied by a 2–3 ppbv increase by renitrification at the 68 hPa pressure level. The observed region of depleted HNO3 is substantially smaller than the region bounded by the NAT existence temperature threshold. Temperature-time histories of air parcels demonstrate that the depletion is more clearly correlated with prior exposure to temperatures a few kelvin above the frost-point. From the combined data we infer the presence

  4. Validation of Cloud Properties From Multiple Satellites Using CALIOP Data

    Science.gov (United States)

    Yost, Christopher R.; Minnis, Patrick; Bedka, Kristopher M.; Heck, Patrick W.; Palikonda, Rabindra; Sun-Mack, Sunny; Trepte, Qing

    2016-01-01

    The NASA Langley Satellite ClOud and Radiative Property retrieval System (SatCORPS) is routinely applied to multispectral imagery from several geostationary and polar-orbiting imagers to retrieve cloud properties for weather and climate applications. Validation of the retrievals with independent datasets is continuously ongoing in order to understand differences caused by calibration, spatial resolution, viewing geometry, and other factors. The CALIOP instrument provides a decade of detailed cloud observations which can be used to evaluate passive imager retrievals of cloud boundaries, thermodynamic phase, cloud optical depth, and water path on a global scale. This paper focuses on comparisons of CALIOP retrievals to retrievals from MODIS, VIIRS, AVHRR, GOES, SEVIRI, and MTSAT. CALIOP is particularly skilled at detecting weakly-scattering cirrus clouds with optical depths less than approx. 0.5. These clouds are often undetected by passive imagers and the effect this has on the property retrievals is discussed.

  5. Simulation of Cloud-aerosol Lidar with Orthogonal Polarization (CALIOP Attenuated Backscatter Profiles Using the Global Model of Aerosol Processes (GLOMAP

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    Young Stuart

    2016-01-01

    Full Text Available To permit the calculation of the radiative effects of atmospheric aerosols, we have linked our aerosol-chemical transport model (CTMGLOMAP to a new radiation module (UKCARADAER. In order to help assess and improve the accuracy of the radiation code, in particular the height dependence of the predicted scattering, we have developed a module that simulates attenuated backscatter (ABS profiles that would be measured by the satellite-borne Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP if it were to sample an atmosphere with the same aerosol loading as predicted by the CTM. Initial results of our comparisons of the predicted ABS profiles with actual CALIOP data are encouraging but some differences are noted, particularly in marine boundary layers where the scattering is currently under-predicted and in dust layers where it is often over-predicted. The sources of these differences are being investigated.

  6. Instrumentation with polarized neutrons

    International Nuclear Information System (INIS)

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

    2009-01-01

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

  7. Depolarization ratio of polar stratospheric clouds in coastal Antarctica: comparison analysis between ground-based Micro Pulse Lidar and space-borne CALIOP observations

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    C. Córdoba-Jabonero

    2013-03-01

    Full Text Available Polar stratospheric clouds (PSCs play an important role in polar ozone depletion, since they are involved in diverse ozone destruction processes (chlorine activation, denitrification. The degree of that ozone reduction is depending on the type of PSCs, and hence on their occurrence. Therefore PSC characterization, mainly focused on PSC-type discrimination, is widely demanded. The backscattering (R and volume linear depolarization (δV ratios are the parameters usually used in lidar measurements for PSC detection and identification. In this work, an improved version of the standard NASA/Micro Pulse Lidar (MPL-4, which includes a built-in depolarization detection module, has been used for PSC observations above the coastal Antarctic Belgrano II station (Argentina, 77.9° S 34.6° W, 256 m a.s.l. since 2009. Examination of the MPL-4 δV feature as a suitable index for PSC-type discrimination is based on the analysis of the two-channel data, i.e., the parallel (p- and perpendicular (s- polarized MPL signals. This study focuses on the comparison of coincident δV-profiles as obtained from ground-based MPL-4 measurements during three Antarctic winters with those reported from the space-borne lidar CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization aboard the CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation satellite in the same period (83 simultaneous cases are analysed for 2009–2011 austral winter times. Three different approaches are considered for the comparison analysis between both lidar profile data sets in order to test the degree of agreement: the correlation coefficient (CC, as a measure of the relationship between both PSC vertical structures; the mean differences together with their root mean square (RMS values found between data sets; and the percentage differences (BIAS, parameter also used in profiling comparisons between CALIOP and other ground-based lidar systems. All of them are examined as a function

  8. An accuracy assessment of the CALIOP/CALIPSO version 2/version 3 daytime aerosol extinction product based on a detailed multi-sensor, multi-platform case study

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    M. Kacenelenbogen

    2011-04-01

    Full Text Available The Cloud Aerosol LIdar with Orthogonal Polarization (CALIOP, on board the CALIPSO platform, has measured profiles of total attenuated backscatter coefficient (level 1 products since June 2006. CALIOP's level 2 products, such as the aerosol backscatter and extinction coefficient profiles, are retrieved using a complex succession of automated algorithms. The goal of this study is to help identify potential shortcomings in the CALIOP version 2 level 2 aerosol extinction product and to illustrate some of the motivation for the changes that have been introduced in the next version of CALIOP data (version 3, released in June 2010. To help illustrate the potential factors contributing to the uncertainty of the CALIOP aerosol extinction retrieval, we focus on a one-day, multi-instrument, multiplatform comparison study during the CALIPSO and Twilight Zone (CATZ validation campaign on 4 August 2007. On that day, we observe a consistency in the Aerosol Optical Depth (AOD values recorded by four different instruments (i.e. space-borne MODerate Imaging Spectroradiometer, MODIS: 0.67 and POLarization and Directionality of Earth's Reflectances, POLDER: 0.58, airborne High Spectral Resolution Lidar, HSRL: 0.52 and ground-based AErosol RObotic NETwork, AERONET: 0.48 to 0.73 while CALIOP AOD is a factor of two lower (0.32 at 532 nm. This case study illustrates the following potential sources of uncertainty in the CALIOP AOD: (i CALIOP's low signal-to-noise ratio (SNR leading to the misclassification and/or lack of aerosol layer identification, especially close to the Earth's surface; (ii the cloud contamination of CALIOP version 2 aerosol backscatter and extinction profiles; (iii potentially erroneous assumptions of the aerosol extinction-to-backscatter ratio (Sa used in CALIOP's extinction retrievals; and (iv calibration coefficient biases in the CALIOP daytime attenuated backscatter coefficient profiles. The use of version 3 CALIOP extinction

  9. Next Generation Polar Seismic Instrumentation Challenges

    Science.gov (United States)

    Parker, T.; Beaudoin, B. C.; Gridley, J.; Anderson, K. R.

    2011-12-01

    Polar region logistics are the limiting factor for deploying deep field seismic arrays. The IRIS PASSCAL Instrument Center, in collaboration with UNAVCO, designed and deployed several systems that address some of the logistical constraints of polar deployments. However, continued logistics' pressures coupled with increasingly ambitious science projects require further reducing the logistics required for deploying both summer and over winter stations. Our focus is to reduce station power requirements and bulk, thereby minimizing the time and effort required to deploy these arrays. We will reduce the weight of the battery bank by incorporating the most applicable new high energy-density battery technology. Using these batteries will require a completely new power management system along with an appropriate smart enclosure. The other aspect will be to integrate the digitizing system with the sensor. Both of these technologies should reduce the install time and shipping volume plus weight while reducing some instrument costs. We will also continue work on an effective Iridium telemetry solution for automated data return. The costs and limitations of polar deep-field science easily justifies a specialized development effort but pays off doubly in that we will continue to leverage the advancements in reduced logistics and increased performance for the benefit of low-latitude seismic research.

  10. Accuracy and precision of polar lower stratospheric temperatures from reanalyses evaluated from A-Train CALIOP and MLS, COSMIC GPS RO, and the equilibrium thermodynamics of supercooled ternary solutions and ice clouds

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    Lambert, Alyn; Santee, Michelle L.

    2018-02-01

    We investigate the accuracy and precision of polar lower stratospheric temperatures (100-10 hPa during 2008-2013) reported in several contemporary reanalysis datasets comprising two versions of the Modern-Era Retrospective analysis for Research and Applications (MERRA and MERRA-2), the Japanese 55-year Reanalysis (JRA-55), the European Centre for Medium-Range Weather Forecasts (ECMWF) interim reanalysis (ERA-I), and the National Oceanic and Atmospheric Administration (NOAA) National Centers for Environmental Prediction (NCEP) Climate Forecast System Reanalysis (NCEP-CFSR). We also include the Goddard Earth Observing System model version 5.9.1 near-real-time analysis (GEOS-5.9.1). Comparisons of these datasets are made with respect to retrieved temperatures from the Aura Microwave Limb Sounder (MLS), Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) Global Positioning System (GPS) radio occultation (RO) temperatures, and independent absolute temperature references defined by the equilibrium thermodynamics of supercooled ternary solutions (STSs) and ice clouds. Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) observations of polar stratospheric clouds are used to determine the cloud particle types within the Aura MLS geometric field of view. The thermodynamic calculations for STS and the ice frost point use the colocated MLS gas-phase measurements of HNO3 and H2O. The estimated bias and precision for the STS temperature reference, over the 68 to 21 hPa pressure range, are 0.6-1.5 and 0.3-0.6 K, respectively; for the ice temperature reference, they are 0.4 and 0.3 K, respectively. These uncertainties are smaller than those estimated for the retrieved MLS temperatures and also comparable to GPS RO uncertainties (bias 0.7 K) in the same pressure range. We examine a case study of the time-varying temperature structure associated with layered ice clouds formed by orographic gravity waves forced by flow over the Palmer Peninsula and

  11. Investigating the frequency and interannual variability in global above-cloud aerosol characteristics with CALIOP and OMI

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    R. Alfaro-Contreras

    2016-01-01

    Full Text Available Seven and a half years (June 2006 to November 2013 of Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP aerosol and cloud layer products are compared with collocated Ozone Monitoring Instrument (OMI aerosol index (AI data and Aqua Moderate Resolution Imaging Spectroradiometer (MODIS cloud products in order to investigate variability in estimates of biannual and monthly above-cloud aerosol (ACA events globally. The active- (CALIOP and passive-based (OMI-MODIS techniques have their advantages and caveats for ACA detection, and thus both are used to derive a thorough and robust comparison of daytime cloudy-sky ACA distribution and climatology. For the first time, baseline above-cloud aerosol optical depth (ACAOD and AI thresholds are derived and examined (AI  =  1.0, ACAOD  =  0.015 for each sensor. Both OMI-MODIS and CALIOP-based daytime spatial distributions of ACA events show similar patterns during both study periods (December–May and (June–November. Divergence exists in some regions, however, such as Southeast Asia during June through November, where daytime cloudy-sky ACA frequencies of up to 10 % are found from CALIOP yet are non-existent from the OMI-based method. Conversely, annual cloudy-sky ACA frequencies of 20–30 % are reported over northern Africa from the OMI-based method yet are largely undetected by the CALIOP-based method. Using a collocated OMI-MODIS-CALIOP data set, our study suggests that the cloudy-sky ACA frequency differences between the OMI-MODIS- and CALIOP-based methods are mostly due to differences in cloud detection capability between MODIS and CALIOP as well as QA flags used. An increasing interannual variability of  ∼  0.3–0.4 % per year (since 2009 in global monthly cloudy-sky ACA daytime frequency of occurrence is found using the OMI-MODIS-based method. Yet, CALIOP-based global daytime ACA frequencies exhibit a near-zero interannual variability. Further analysis suggests

  12. Instrumentation to handle thermal polarized neutron beams

    NARCIS (Netherlands)

    Kraan, W.H.

    2004-01-01

    In this thesis we investigate devices needed to handle the polarization of thermal neutron beams: Ï/2-flippers (to start/stop Larmor precession) and Ï-flippers (to reverse polarization/precession direction) and illustrate how these devices are used to investigate the properties of matter and of the

  13. Instrument performance and simulation verification of the POLAR detector

    Science.gov (United States)

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

    2017-11-01

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

  14. Instrument Performance and Simulation Verification of the POLAR Detector

    OpenAIRE

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

    2017-01-01

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

  15. A method of detecting sea fogs using CALIOP data and its application to improve MODIS-based sea fog detection

    International Nuclear Information System (INIS)

    Wu, Dong; Lu, Bo; Zhang, Tianche; Yan, Fengqi

    2015-01-01

    A method to detect sea fogs from the measurement data acquired by the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) aboard the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite is proposed in this paper. Because of the unique capability of vertical-resolved measurements, sea fogs and low clouds can be more easily distinguished in the CALIOP data compared with passive satellite measurements. Yellow Sea where sea fogs occur frequently is selected to test the method. Nine cases of daytime sea fog events from 2008 to 2011 in the Yellow Sea are studied intensively to characterize the remotely sensed radiation properties of various targets, such as clear-sky sea surface, sea fog, low cloud and high cloud. These fog cases are then used in an attempt to evaluate sea fogs identified from the MODIS measurements. The method proposed in this paper can also be used for nighttime cases. Multi-year sea fog dataset can be made from the CALIOP measurement and used to validate the MODIS sea fog detection. - Highlights: • A method of sea fog detection from the CALIOP measurements is proposed. • CALIOP VFM and 532-nm attenuated backscatter products are integrated used. • Sea fogs and low clouds can be more easily distinguished in the CALIOP data. • 9 Cases of daytime sea fog events in the Yellow Sea are selected to test the method. • The MODIS sea fog detections are evaluated using the collocated CALIOP data

  16. Solar Spectral Lines with Special Polarization Properties for the Calibration of Instrument Polarization

    Energy Technology Data Exchange (ETDEWEB)

    Li, W.; Casini, R.; Alemán, T. del Pino; Judge, P. G. [High Altitude Observatory, National Center for Atmospheric Research 1, P.O. Box 3000, Boulder, CO 80307-3000 (United States)

    2017-10-20

    We investigate atomic transitions that have previously been identified as having zero polarization from the Zeeman effect. Our goal is to identify spectral lines that can be used for the calibration of instrumental polarization of large astronomical and solar telescopes, such as the Daniel K. Inouye Solar Telescope, which is currently under construction on Haleakala. We use a numerical model that takes into account the generation of scattering polarization and its modification by the presence of a magnetic field of arbitrary strength. We adopt values for the Landé factors from spectroscopic measurements or semi-empirical results, thus relaxing the common assumption of LS-coupling previously used in the literature. The mechanisms dominating the polarization of particular transitions are identified, and we summarize groups of various spectral lines useful for the calibration of spectropolarimetric instruments, classified according to their polarization properties.

  17. Enhancements to the CALIOP Aerosol Subtyping and Lidar Ratio Selection Algorithms for Level II Version 4

    Science.gov (United States)

    Omar, A. H.; Tackett, J. L.; Vaughan, M. A.; Kar, J.; Trepte, C. R.; Winker, D. M.

    2016-12-01

    This presentation describes several enhancements planned for the version 4 aerosol subtyping and lidar ratio selection algorithms of the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument. The CALIOP subtyping algorithm determines the most likely aerosol type from CALIOP measurements (attenuated backscatter, estimated particulate depolarization ratios δe, layer altitude), and surface type. The aerosol type, so determined, is associated with a lidar ratio (LR) from a discrete set of values. Some of these lidar ratios have been updated in the version 4 algorithms. In particular, the dust and polluted dust will be adjusted to reflect the latest measurements and model studies of these types. Version 4 eliminates the confusion between smoke and clean marine aerosols seen in version 3 by modifications to the elevated layer flag definitions used to identify smoke aerosols over the ocean. In the subtyping algorithms pure dust is determined by high estimated particulate depolarization ratios [δe > 0.20]. Mixtures of dust and other aerosol types are determined by intermediate values of the estimated depolarization ratio [0.075limited to mixtures of dust and smoke, the so called polluted dust aerosol type. To differentiate between mixtures of dust and smoke, and dust and marine aerosols, a new aerosol type will be added in the version 4 data products. In the revised classification algorithms, polluted dust will still defined as dust + smoke/pollution but in the marine boundary layer instances of moderate depolarization will be typed as dusty marine aerosols with a lower lidar ratio than polluted dust. The dusty marine type introduced in version 4 is modeled as a mixture of dust + marine aerosol. To account for fringes, the version 4 Level 2 algorithms implement Subtype Coalescence Algorithm for AeRosol Fringes (SCAARF) routine to detect and classify fringe of aerosol plumes that are detected at 20 km or 80 km horizontal resolution at the plume base. These

  18. The comparison of MODIS-Aqua (C5 and CALIOP (V2 & V3 aerosol optical depth

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    J. Redemann

    2012-03-01

    Full Text Available We assess the consistency between instantaneously collocated level-2 aerosol optical depth (AOD retrievals from MODIS-Aqua (C5 and CALIOP (Version 2 & 3, comparing the standard MODIS AOD (MYD04_L2 data to the AOD calculated from CALIOP aerosol extinction profiles for both the previous release (V2 and the latest release (V3 of CALIOP data. Based on data collected in January 2007, we investigate the most useful criteria for screening the MODIS and CALIOP retrievals to achieve the best agreement between the two data sets. Applying these criteria to eight months of data (Jan, Apr, Jul, Oct 2007 and 2009, we find an order of magnitude increase for the CALIOP V3 data density (by comparison to V2, that is generally accompanied by equal or better agreement with MODIS AOD. Differences in global, monthly mean, over-ocean AOD (532 nm between CALIOP and MODIS range between 0.03 and 0.04 for CALIOP V3, with CALIOP generally biased low, when all available data from both sensors are considered. Root-mean-squares (RMS differences in instantaneously collocated AOD retrievals by the two instruments are reduced from values ranging between 0.14 and 0.19 using the unscreened V3 data to values ranging from 0.09 to 0.1 for the screened data. A restriction to scenes with cloud fractions less than 1% (as defined in the MODIS aerosol retrievals generally results in improved correlation (R2>0.5, except for the month of July when correlations remain relatively lower. Regional assessments show hot spots in disagreement between the two sensors in Asian outflow during April and off the coast of South Africa in July.

  19. Polarization Characteristics Inferred From the Radio Receiver Instrument on the Enhanced Polar Outflow Probe

    Science.gov (United States)

    Danskin, Donald W.; Hussey, Glenn C.; Gillies, Robert G.; James, H. Gordon; Fairbairn, David T.; Yau, Andrew W.

    2018-02-01

    The Radio Receiver Instrument (RRI) on the CAScade, Smallsat, and Ionospheric Polar Explorer/enhanced Polar Outflow Probe (CASSIOPE/e-POP) satellite was used to receive continuous wave and binary phase shift keyed transmissions from a high-frequency transmitter located in Ottawa, ON, Canada during April 2016 to investigate how the ionosphere affects the polarization characteristics of transionospheric high-frequency radio waves. The spacecraft orientation was continuously slewed to maintain the dipole orientation in a plane perpendicular to the direction toward the transmitter, enabling the first in situ planar polarization determination for continuous wave and binary phase shift keyed modulated radio waves from space at times when the wave frequency is at least 1.58 times the plasma frequency. The Stokes parameters and polarization characteristics were derived from the measured data and interpreted using an existing ray tracing model. For the southern part of the passes, the power was observed to oscillate between the two dipoles of RRI, which was attributed to Faraday rotation of the radio waves. For the first time, a reversal in the rate of change of orientation angle was observed where the minimum in modeled Faraday rotation occurred. The reversal point was poleward of the point of closest approach between the satellite and transmitter; this was explained by the variations of total electron content and component of magnetic field along the direction of propagation. The received signals show both quasi-longitudinal (QL) and quasi-transverse characteristics. South of the transmitter the QL regime is dominant. Around the reversal point, a combination of QL and quasi-transverse nature was observed.

  20. RECOVERY OF LARGE ANGULAR SCALE CMB POLARIZATION FOR INSTRUMENTS EMPLOYING VARIABLE-DELAY POLARIZATION MODULATORS

    Energy Technology Data Exchange (ETDEWEB)

    Miller, N. J.; Marriage, T. A.; Appel, J. W.; Bennett, C. L.; Eimer, J.; Essinger-Hileman, T.; Harrington, K.; Rostem, K.; Watts, D. J. [Department of Physics and Astronomy, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218 (United States); Chuss, D. T. [Department of Physics, Villanova University, 800 E Lancaster, Villanova, PA 19085 (United States); Wollack, E. J.; Fixsen, D. J.; Moseley, S. H.; Switzer, E. R., E-mail: Nathan.J.Miller@nasa.gov [Observational Cosmology Laboratory, Code 665, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2016-02-20

    Variable-delay Polarization Modulators (VPMs) are currently being implemented in experiments designed to measure the polarization of the cosmic microwave background on large angular scales because of their capability for providing rapid, front-end polarization modulation and control over systematic errors. Despite the advantages provided by the VPM, it is important to identify and mitigate any time-varying effects that leak into the synchronously modulated component of the signal. In this paper, the effect of emission from a 300 K VPM on the system performance is considered and addressed. Though instrument design can greatly reduce the influence of modulated VPM emission, some residual modulated signal is expected. VPM emission is treated in the presence of rotational misalignments and temperature variation. Simulations of time-ordered data are used to evaluate the effect of these residual errors on the power spectrum. The analysis and modeling in this paper guides experimentalists on the critical aspects of observations using VPMs as front-end modulators. By implementing the characterizations and controls as described, front-end VPM modulation can be very powerful for mitigating 1/f noise in large angular scale polarimetric surveys. None of the systematic errors studied fundamentally limit the detection and characterization of B-modes on large scales for a tensor-to-scalar ratio of r = 0.01. Indeed, r < 0.01 is achievable with commensurately improved characterizations and controls.

  1. Refinement of the CALIOP cloud mask algorithm

    Science.gov (United States)

    Katagiri, Shuichiro; Sato, Kaori; Ohta, Kohei; Okamoto, Hajime

    2018-04-01

    A modified cloud mask algorithm was applied to the CALIOP data to have more ability to detect the clouds in the lower atmosphere. In this algorithm, we also adopt the fully attenuation discrimination and the remain noise estimation using the data obtained at an altitude of 40 km to avoid contamination of stratospheric aerosols. The new cloud mask shows an increase in the lower cloud fraction. Comparison of the results to the data observed with a PML ground observation was also made.

  2. The Atacama Cosmology Telescope: The Polarization-Sensitive ACTPol Instrument

    Science.gov (United States)

    Thornton, R. J.; Ade, P. A. R.; Aiola, S.; Angile, F. E.; Amiri, M.; Beall, J. A.; Becker, D. T.; Cho, H.-M.; Choi, S. K.; Corlies, P.; hide

    2016-01-01

    The Atacama Cosmology Telescope (ACT) makes high angular resolution measurements of anisotropies in the Cosmic Microwave Background (CMB) at millimeter wavelengths. We describe ACTPol, an upgraded receiver for ACT, which uses feedhorn-coupled, polarization-sensitive detector arrays, a 3deg field of view, 100 mK cryogenics with continuous cooling, and meta material antireflection coatings. ACTPol comprises three arrays with separate cryogenic optics: two arrays at a central frequency of 148 GHz and one array operating simultaneously at both 97 GHz and 148 GHz. The combined instrument sensitivity, angular resolution, and sky coverage are optimized for measuring angular power spectra, clusters via the thermal Sunyaev-Zel'dovich (SZ) and kinetic SZ signals, and CMB lensing due to large-scale structure. The receiver was commissioned with its first 148 GHz array in 2013, observed with both 148 GHz arrays in 2014, and has recently completed its first full season of operations with the full suite of three arrays. This paper provides an overview of the design and initial performance of the receiver and related systems.

  3. The Atacama Cosmology Telescope: The Polarization-sensitive ACTPol Instrument

    Science.gov (United States)

    Thornton, R. J.; Ade, P. A. R.; Aiola, S.; Angilè, F. E.; Amiri, M.; Beall, J. A.; Becker, D. T.; Cho, H.-M.; Choi, S. K.; Corlies, P.; Coughlin, K. P.; Datta, R.; Devlin, M. J.; Dicker, S. R.; Dünner, R.; Fowler, J. W.; Fox, A. E.; Gallardo, P. A.; Gao, J.; Grace, E.; Halpern, M.; Hasselfield, M.; Henderson, S. W.; Hilton, G. C.; Hincks, A. D.; Ho, S. P.; Hubmayr, J.; Irwin, K. D.; Klein, J.; Koopman, B.; Li, Dale; Louis, T.; Lungu, M.; Maurin, L.; McMahon, J.; Munson, C. D.; Naess, S.; Nati, F.; Newburgh, L.; Nibarger, J.; Niemack, M. D.; Niraula, P.; Nolta, M. R.; Page, L. A.; Pappas, C. G.; Schillaci, A.; Schmitt, B. L.; Sehgal, N.; Sievers, J. L.; Simon, S. M.; Staggs, S. T.; Tucker, C.; Uehara, M.; van Lanen, J.; Ward, J. T.; Wollack, E. J.

    2016-12-01

    The Atacama Cosmology Telescope (ACT) makes high angular resolution measurements of anisotropies in the Cosmic Microwave Background (CMB) at millimeter wavelengths. We describe ACTPol, an upgraded receiver for ACT, which uses feedhorn-coupled, polarization-sensitive detector arrays, a 3° field of view, 100 mK cryogenics with continuous cooling, and meta material antireflection coatings. ACTPol comprises three arrays with separate cryogenic optics: two arrays at a central frequency of 148 GHz and one array operating simultaneously at both 97 GHz and 148 GHz. The combined instrument sensitivity, angular resolution, and sky coverage are optimized for measuring angular power spectra, clusters via the thermal Sunyaev–Zel’dovich (SZ) and kinetic SZ signals, and CMB lensing due to large-scale structure. The receiver was commissioned with its first 148 GHz array in 2013, observed with both 148 GHz arrays in 2014, and has recently completed its first full season of operations with the full suite of three arrays. This paper provides an overview of the design and initial performance of the receiver and related systems.

  4. Evaluating Nighttime CALIOP 0.532 micron Aerosol Optical Depth and Extinction Coefficient Retrievals

    Science.gov (United States)

    Campbell, J. R.; Tackett, J. L.; Reid, J. S.; Zhang, J.; Curtis, C. A.; Hyer, E. J.; Sessions, W. R.; Westphal, D. L.; Prospero, J. M.; Welton, E. J.; hide

    2012-01-01

    NASA Cloud Aerosol Lidar with Orthogonal Polarization (CALIOP) Version 3.01 5-km nighttime 0.532 micron aerosol optical depth (AOD) datasets from 2007 are screened, averaged and evaluated at 1 deg X 1 deg resolution versus corresponding/co-incident 0.550 micron AOD derived using the US Navy Aerosol Analysis and Prediction System (NAAPS), featuring two-dimensional variational assimilation of quality-assured NASA Moderate Resolution Imaging Spectroradiometer (MODIS) and Multi-angle Imaging Spectroradiometer (MISR) AOD. In the absence of sunlight, since passive radiometric AOD retrievals rely overwhelmingly on scattered radiances, the model represents one of the few practical global estimates available from which to attempt such a validation. Daytime comparisons, though, provide useful context. Regional-mean CALIOP vertical profiles of night/day 0.532 micron extinction coefficient are compared with 0.523/0.532 micron ground-based lidar measurements to investigate representativeness and diurnal variability. In this analysis, mean nighttime CALIOP AOD are mostly lower than daytime (0.121 vs. 0.126 for all aggregated data points, and 0.099 vs. 0.102 when averaged globally per normalised 1 deg. X 1 deg. bin), though the relationship is reversed over land and coastal regions when the data are averaged per normalised bin (0.134/0.108 vs. 0140/0.112, respectively). Offsets assessed within single bins alone approach +/- 20 %. CALIOP AOD, both day and night, are higher than NAAPS over land (0.137 vs. 0.124) and equal over water (0.082 vs. 0.083) when averaged globally per normalised bin. However, for all data points inclusive, NAAPS exceeds CALIOP over land, coast and ocean, both day and night. Again, differences assessed within single bins approach 50% in extreme cases. Correlation between CALIOP and NAAPS AOD is comparable during both day and night. Higher correlation is found nearest the equator, both as a function of sample size and relative signal magnitudes inherent at

  5. Architectures and assessment of next-generation CMB polarization instruments

    Data.gov (United States)

    National Aeronautics and Space Administration — Cosmological inflation predicts a background of gravitational waves that imprint a characteristic polarized pattern on the CMB. This signal is degraded by...

  6. 9+ Years of CALIOP PSC Data: An Evolving Climatology

    Science.gov (United States)

    Pitts, Michael C.; Poole, Lamont R.

    2015-01-01

    Polar stratospheric clouds (PSCs) play key roles in the springtime chemical depletion of ozone at high latitudes. PSC particles provide sites for heterogeneous chemical reactions that transform stable chlorine and bromine reservoir species into highly reactive ozone-destructive forms. Furthermore, large nitric acid trihydrate (NAT) PSC particles can irreversibly redistribute odd nitrogen through gravitational sedimentation, which prolongs the ozone depletion process by slowing the reformation of the stable chlorine reservoirs. However, there are still significant gaps in our understanding of PSC processes, particularly concerning the details of NAT particle formation. Spaceborne observations from the CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) lidar on the CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) satellite are providing a rich new dataset for studying PSCs on unprecedented vortex-wide scales. In this paper, we examine the vertical and spatial distribution of PSCs in the Antarctic and Arctic on vortex-wide scales for entire PSC seasons over the more than nine-year data record.

  7. A Statistical Review of CALIOP Version 3 and Version 4 Cloud Aerosol Discrimination

    Science.gov (United States)

    Zeng, S.

    2016-12-01

    The Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) on board the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) mission has now delivered a 10-year record of high-resolution profiles of backscatter at 532 nm and 1064 nm and linear depolarization at 532 nm. These long-term active sensor measurements at global scale have led to significant advances in our understanding of the vertical distribution of clouds and aerosols in the atmosphere. In the fall of 2016, the CALIPSO science team is scheduled to release a new version of their cloud and aerosol data products. The new cloud and aerosol discrimination products are derived using updated probability density functions that account for numerous improvements to the CALIOP calibration and the use of the GMAO MERRA-2 meteorological data. Moreover, the CAD algorithm is now applied to all layers detected, thus greatly improving the identification of such features as overshooting convective clouds, stratospheric aerosol layers, and high intensity dust storms. Post-processing modules are added to the standard CAD algorithm to ensure proper identification of (for example) the tenuous edges of cirrus clouds and water clouds lying beneath optically dense smoke layers. This work presents statistical comparisons between the CALIOP version 3 and version 4 data sets. Areas of improvement are highlighted, sources of continuing uncertainty are discussed and a list of best practices for data users is provided.

  8. Current activities and plans for polarized neutron instruments of the JSNS/J-PARC project

    International Nuclear Information System (INIS)

    Furusaka, M.

    2005-01-01

    Neutron polarization is one of the key technologies for the next generation megawatt-class pulsed spallation neutron sources, such as SNS in the US and the JSNS in Japan. To polarize or analyze neutron spin, several techniques are under development in Japan: a small d-spacing magnetic multilayer mirror, spin exchange type He-3 filter and a dynamical proton polarizer. Several application techniques related to polarized neutrons are also under development, such as, a microwave-induced optical nuclear polarization technique, which allows us to polarize protons in naphtalene doped with pentacene at 77 K; neutron focusing-SANS instrument utilizing a focusing magnet; a Drabkin spin-filter instrument that has two filters in series for neutron-pulse shaping

  9. The polarized neutron small-angle scattering instrument at BENSC Berlin

    International Nuclear Information System (INIS)

    Keller, T.; Krist, T.; Danzig, A.; Keiderling, U.; Mezei, F.; Wiedenmann, A.

    2000-01-01

    A polarized neutron beam has been installed at the small-angle neutron-scattering instrument V4 at BENSC Berlin. The main component of this new option is a 1.8 m long cavity transmission polarizer. The advantages of this device compared to the conventional bender polarizers are: (i) high transmission (35% of unpolarized beam at λ=6 A); (ii) the polarization is better than 93% in the wavelength band 4 A 3 O 4 particles embedded in a glass matrix) are presented and compared to a measurement with unpolarized neutrons

  10. Long range radio tracking of sea turtles and polar bear: Instrumentation and preliminary results

    Science.gov (United States)

    Baldwin, H. A.

    1972-01-01

    Instrumentation developed for studies of path behavior of the green sea turtle and migration movement of polar bear is described. Preliminary results bearing on navigation ability in these species are presented. Both species operate in difficult environments, and the problems faced in the design of electronic instrumentation for these studies are not completely specified at this time. However, the critical factors yet to be understood are primarily related to the behavior of instrumented animals. The data obtained with these experimental techniques are included, first to illustrate the technique and, second to provide initial preliminary results bearing on animal navigation.

  11. Remote sensing of aerosols by synergy of caliop and modis

    OpenAIRE

    Kudo Rei; Nishizawa Tomoaki; Higurashi Akiko; Oikawa Eiji

    2018-01-01

    For the monitoring of the global 3-D distribution of aerosol components, we developed the method to retrieve the vertical profiles of water-soluble, light absorbing carbonaceous, dust, and sea salt particles by the synergy of CALIOP and MODIS data. The aerosol product from the synergistic method is expected to be better than the individual products of CALIOP and MODIS. We applied the method to the biomass-burning event in Africa and the dust event in West Asia. The reasonable results were obt...

  12. Neutron xyz - polarization analysis at a time-of-flight instrument

    Energy Technology Data Exchange (ETDEWEB)

    Ehlers, Georg [ORNL; Stewart, John Ross [ISIS Facility, Rutherford Appleton Laboratory; Andersen, Ken [ESS

    2015-01-01

    When implementing a dedicated polarization analysis setup at a neutron time-of-flight instrument with a large area detector, one faces enormous challenges. Nevertheless, significant progress has been made towards this goal over the last few years. This paper addresses systematic limitations of the traditional method that is used to make these measurements, and a possible strategy to overcome these limitations. This will be important, for diffraction as well as inelastic experiments, where the scattering occurs mostly out-of-plane.

  13. SANS polarization analysis at V4 SANS instrument of HMI Berlin

    International Nuclear Information System (INIS)

    Keiderling, U; Wiedenmann, A; Rupp, A; Klenke, J; Heil, W

    2008-01-01

    The V4 instrument has recently been upgraded with a 3 He spin filter cell, placed directly in the homogeneous field B of the sample magnet, to enhance the SANSPOL option for polarization analysis. The prototype setup was still affected by: (a) a quick relaxation of the 3 He nuclear polarization in the cell with a time constant of only ≈130 min which significantly changes the spin filter transmissions T + and T − for neutrons polarized parallel I + and anti-parallel I − to B, and (b) the absence of a flipping aid behind the sample. The usual polarization analysis procedure, expecting virtually time-independent transmissions and a second flipping device, is therefore not applicable. We present an alternative way of polarization analysis, developed especially for this case of a spin filter cell with insufficient time stability, and not requiring a second flipper. A concentrated Co-ferrofluid sample 'MFT3N' was measured with the spin filter cell for 5.5 h. From the time-dependent change of I + and I − caused by the change of T + and T − , the spin-flip and non-spin-flip components of the scattering were calculated by fitting procedures. The two-dimensional flip patterns obtained represent the purely magnetic scattering contribution, featuring the typical (sin αcos α) 2 angular behavior expected for superparamagnetic systems

  14. Remote sensing of aerosols by synergy of caliop and modis

    Directory of Open Access Journals (Sweden)

    Kudo Rei

    2018-01-01

    Full Text Available For the monitoring of the global 3-D distribution of aerosol components, we developed the method to retrieve the vertical profiles of water-soluble, light absorbing carbonaceous, dust, and sea salt particles by the synergy of CALIOP and MODIS data. The aerosol product from the synergistic method is expected to be better than the individual products of CALIOP and MODIS. We applied the method to the biomass-burning event in Africa and the dust event in West Asia. The reasonable results were obtained; the much amount of the water-soluble and light absorbing carbonaceous particles were estimated in the biomass-burning event, and the dust particles were estimated in the dust event.

  15. Remote sensing of aerosols by synergy of caliop and modis

    Science.gov (United States)

    Kudo, Rei; Nishizawa, Tomoaki; Higurashi, Akiko; Oikawa, Eiji

    2018-04-01

    For the monitoring of the global 3-D distribution of aerosol components, we developed the method to retrieve the vertical profiles of water-soluble, light absorbing carbonaceous, dust, and sea salt particles by the synergy of CALIOP and MODIS data. The aerosol product from the synergistic method is expected to be better than the individual products of CALIOP and MODIS. We applied the method to the biomass-burning event in Africa and the dust event in West Asia. The reasonable results were obtained; the much amount of the water-soluble and light absorbing carbonaceous particles were estimated in the biomass-burning event, and the dust particles were estimated in the dust event.

  16. African Dust Fertilizing the Amazon Rainforest: An Assessment with Seven-year Record of CALIOP Measurements

    Science.gov (United States)

    Yu, H.; Chin, M.; Yuan, T.; Bian, H.; Prospero, J. M.; Omar, A. H.; Remer, L. A.; Winker, D. M.; Yang, Y.; Zhang, Y.; Zhang, Z.

    2014-12-01

    The productivity of Amazon rainforest is constrained by the availability of nutrients, in particular phosphorus (P). Deposition of transported African dust in boreal winter and spring is considered an important nutrient input for the Amazon Basin, though its magnitude is not well qunatified. This study provides a remote sensing observation-based estimate of dust deposition in the Amazon Basin using a 7-year (2007-2013) record of three dimensional (3D) distributions of aerosol in both cloud-free and above-cloud conditions from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP). It is estimated that the 7-year average of dust deposition into the Amazon Basin amounts to 15.1 ~ 32.1 Tg a-1 (Tg = 1012 g). This imported dust could provide 0.012 ~ 0.025 Tg P a-1 or equivalent to 12 ~ 26 g P ha-1 a-1 to fertilize the Amazon rainforest, which largely compensates the hydrological loss of P. The CLAIOP-based estimate agrees better with estimates from in-situ measurements and model simulations than what has been reported in literature. The closer agreement benefits from a more realistic geographic definition of the Amazon Basin and inclusion of meridional dust transport calculation in addition to the 3D nature of CALIOP aerosol measurements. The trans-Atlantic transport and deposition of dust shows strong interannual variations that are found to correlate with the North Atlantic Oscillation index in the winter season and anticorrelate with the prior-year Sahel Precipitation Index on an annual basis. Uncertainties associated with the estimate will also be discussed.

  17. LabVIEW-based control software for para-hydrogen induced polarization instrumentation

    International Nuclear Information System (INIS)

    Agraz, Jose; Grunfeld, Alexander; Li, Debiao; Cunningham, Karl; Willey, Cindy; Pozos, Robert; Wagner, Shawn

    2014-01-01

    The elucidation of cell metabolic mechanisms is the modern underpinning of the diagnosis, treatment, and in some cases the prevention of disease. Para-Hydrogen induced polarization (PHIP) enhances magnetic resonance imaging (MRI) signals over 10 000 fold, allowing for the MRI of cell metabolic mechanisms. This signal enhancement is the result of hyperpolarizing endogenous substances used as contrast agents during imaging. PHIP instrumentation hyperpolarizes Carbon-13 ( 13 C) based substances using a process requiring control of a number of factors: chemical reaction timing, gas flow, monitoring of a static magnetic field (B o ), radio frequency (RF) irradiation timing, reaction temperature, and gas pressures. Current PHIP instruments manually control the hyperpolarization process resulting in the lack of the precise control of factors listed above, resulting in non-reproducible results. We discuss the design and implementation of a LabVIEW based computer program that automatically and precisely controls the delivery and manipulation of gases and samples, monitoring gas pressures, environmental temperature, and RF sample irradiation. We show that the automated control over the hyperpolarization process results in the hyperpolarization of hydroxyethylpropionate. The implementation of this software provides the fast prototyping of PHIP instrumentation for the evaluation of a myriad of 13 C based endogenous contrast agents used in molecular imaging

  18. LabVIEW-based control software for para-hydrogen induced polarization instrumentation.

    Science.gov (United States)

    Agraz, Jose; Grunfeld, Alexander; Li, Debiao; Cunningham, Karl; Willey, Cindy; Pozos, Robert; Wagner, Shawn

    2014-04-01

    The elucidation of cell metabolic mechanisms is the modern underpinning of the diagnosis, treatment, and in some cases the prevention of disease. Para-Hydrogen induced polarization (PHIP) enhances magnetic resonance imaging (MRI) signals over 10,000 fold, allowing for the MRI of cell metabolic mechanisms. This signal enhancement is the result of hyperpolarizing endogenous substances used as contrast agents during imaging. PHIP instrumentation hyperpolarizes Carbon-13 ((13)C) based substances using a process requiring control of a number of factors: chemical reaction timing, gas flow, monitoring of a static magnetic field (Bo), radio frequency (RF) irradiation timing, reaction temperature, and gas pressures. Current PHIP instruments manually control the hyperpolarization process resulting in the lack of the precise control of factors listed above, resulting in non-reproducible results. We discuss the design and implementation of a LabVIEW based computer program that automatically and precisely controls the delivery and manipulation of gases and samples, monitoring gas pressures, environmental temperature, and RF sample irradiation. We show that the automated control over the hyperpolarization process results in the hyperpolarization of hydroxyethylpropionate. The implementation of this software provides the fast prototyping of PHIP instrumentation for the evaluation of a myriad of (13)C based endogenous contrast agents used in molecular imaging.

  19. Development of a neutron-polarizing device based on a quadrupole magnet and its application to a focusing SANS instrument

    International Nuclear Information System (INIS)

    Oku, Takayuki

    2009-01-01

    We have investigated suitable magnetic field distribution to polarize neutrons based only on the electromagnetic interaction between a neutron magnetic moment and magnetic field, and found out a quadrupole field was the most suitable among simple multipole fields. Then we constructed a quadrupole magnet with a Halbach magnetic circuit as the neutron polarizing device. A cold neutron polarizing experiment of the quadrupole magnet was performed at the beamline C3-1-2-1 (NOP) of JRR-3 at JAEA. By passing through the aperture of the quadrupole magnet, positive and negative polarity neutrons are accelerated in opposite directions and spatially separated. Therefore, we extracted the one-spin component and analyzed its polarization degree. As a result very high neutron polarization degree P=0.9993±0.0025 was obtained. Then the quadrupole magnet was installed into the polarized neutron focusing geometry SANS instrument SANS-J-II of JRR-3. The instrument performance was enhanced by about 10 times compared with the case with the magnetic supermirror as the neutron polarizing device. The details are shown and discussed. (author)

  20. Characterizing the Vertical Profile of Aerosol Particle Extinction and Linear Depolarization over Southeast Asia and the Maritime Continent: The 2007-2009 View from CALIOP

    Science.gov (United States)

    Campbell, James R.; Reid, Jeffrey S.; Westphal, Douglas L.; Zhang, Jianglong; Tackett, Jason L.; Chew, Boon Ning; Welton, Ellsworth J.; Shimizu, Atsushi; Sugimoto, Nobuo; Aoki, Kazuma; hide

    2012-01-01

    Vertical profiles of 0.532 µm aerosol particle extinction coefficient and linear volume depolarization ratio are described for Southeast Asia and the Maritime Continent. Quality-screened and cloud-cleared Version 3.01 Level 2 NASA Cloud Aerosol Lidar with Orthogonal Polarization (CALIOP) 5-km Aerosol Profile datasets are analyzed from 2007 to 2009. Numerical simulations from the U.S. Naval Aerosol Analysis and Predictive System (NAAPS), featuring two-dimensional variational assimilation of NASA Moderate Resolution Imaging Spectroradiometer and Multi-angle Imaging Spectro- Radiometer quality-assured datasets, combined with regional ground-based lidar measurements, are considered for assessing CALIOP retrieval performance, identifying bias, and evaluating regional representativeness. CALIOP retrievals of aerosol particle extinction coefficient and aerosol optical depth (AOD) are high over land and low over open waters relative to NAAPS (0.412/0.312 over land for all data points inclusive, 0.310/0.235 when the per bin average is used and each is treated as single data points; 0.102/0.151 and 0.086/0.124, respectively, over ocean). Regional means, however, are very similar (0.180/0.193 for all data points and 0.155/0.159 when averaged per normalized bin), as the two factors offset one another. The land/ocean offset is investigated, and discrepancies attributed to interpretation of particle composition and a-priori assignment of the extinction-to-backscatter ratio ("lidar ratio") necessary for retrieving the extinction coefficient from CALIOP signals. Over land, NAAPS indicates more dust present than CALIOP algorithms are identifying, indicating a likely assignment of a higher lidar ratio representative of more absorptive particles. NAAPS resolvesmore smoke overwater than identified with CALIOP, indicating likely usage of a lidar ratio characteristic of less absorptive particles to be applied that biases low AOD there. Over open waters except within the Bay of Bengal

  1. The Thirty Gigahertz Instrument Receiver for the QUIJOTE Experiment: Preliminary Polarization Measurements and Systematic-Error Analysis

    Directory of Open Access Journals (Sweden)

    Francisco J. Casas

    2015-08-01

    Full Text Available This paper presents preliminary polarization measurements and systematic-error characterization of the Thirty Gigahertz Instrument receiver developed for the QUIJOTE experiment. The instrument has been designed to measure the polarization of Cosmic Microwave Background radiation from the sky, obtaining the Q, U, and I Stokes parameters of the incoming signal simultaneously. Two kinds of linearly polarized input signals have been used as excitations in the polarimeter measurement tests in the laboratory; these show consistent results in terms of the Stokes parameters obtained. A measurement-based systematic-error characterization technique has been used in order to determine the possible sources of instrumental errors and to assist in the polarimeter calibration process.

  2. CALIOPE airborne CO{sub 2} DIAL (CACDI) system design

    Energy Technology Data Exchange (ETDEWEB)

    Mietz, D.; Archuleta, B.; Archuleta, J. [and others

    1997-09-01

    Los Alamos National Laboratory is currently developing an airborne CO{sub 2} Differential Absorption Lidar (DIAL) system based on second generation technology demonstrated last summer at NTS. The CALIOPE Airborne CO{sub 2} DIAL (CACDI) system requirements have been compiled based on the mission objectives and SONDIAL model trade studies. Subsystem designs have been developed based on flow down from these system requirements, as well as experience gained from second generation ground tests and N-ABLE (Non-proliferation AirBorne Lidar Experiments) airborne experiments. This paper presents the CACDI mission objectives, system requirements, the current subsystem design, and provides an overview of the airborne experimental plan.

  3. Operational air quality forecasting system for Spain: CALIOPE

    Science.gov (United States)

    Baldasano, J. M.; Piot, M.; Jorba, O.; Goncalves, M.; Pay, M.; Pirez, C.; Lopez, E.; Gasso, S.; Martin, F.; García-Vivanco, M.; Palomino, I.; Querol, X.; Pandolfi, M.; Dieguez, J. J.; Padilla, L.

    2009-12-01

    The European Commission (EC) and the United States Environmental Protection Agency (US-EPA) have shown great concerns to understand the transport and dynamics of pollutants in the atmosphere. According to the European directives (1996/62/EC, 2002/3/EC, 2008/50/EC), air quality modeling, if accurately applied, is a useful tool to understand the dynamics of air pollutants, to analyze and forecast the air quality, and to develop programs reducing emissions and alert the population when health-related issues occur. The CALIOPE project, funded by the Spanish Ministry of the Environment, has the main objective to establish an air quality forecasting system for Spain. A partnership of four research institutions composes the CALIOPE project: the Barcelona Supercomputing Center (BSC), the center of investigation CIEMAT, the Earth Sciences Institute ‘Jaume Almera’ (IJA-CSIC) and the CEAM Foundation. CALIOPE will become the official Spanish air quality operational system. This contribution focuses on the recent developments and implementation of the integrated modelling system for the Iberian Peninsula (IP) and Canary Islands (CI) with a high spatial and temporal resolution (4x4 sq. km for IP and 2x2 sq. km for CI, 1 hour), namely WRF-ARW/HERMES04/CMAQ/BSC-DREAM. The HERMES04 emission model has been specifically developed as a high-resolution (1x1 sq. km, 1 hour) emission model for Spain. It includes biogenic and anthropogenic emissions such as on-road and paved-road resuspension production, power plant generation, ship and plane traffic, airports and ports activities, industrial and agricultural sectors as well as domestic and commercial emissions. The qualitative and quantitative evaluation of the model was performed for a reference year (2004) using data from ground-based measurement networks. The products of the CALIOPE system will provide 24h and 48h forecasts for O3, NO2, SO2, CO, PM10 and PM2.5 at surface level. An operational evaluation system has been developed

  4. A new instrumental set-up for polarized neutron scattering experiments

    International Nuclear Information System (INIS)

    Schmidt, Wolfgang; Ohl, Michael

    2005-01-01

    Neutron scattering with polarization analysis is a powerful tool to determine magnetic structures and excitations. A common setup is to mount the sample at the center of a Helmholtz-type coil which can provide a magnetic field of any direction at the sample position and also a guide field along the neutron flight paths around the sample. Recent experiments showed quite a high demand for measurements at low momentum transfers. For the corresponding low scattering angles air scattering gives rise to a very large background. For this reason we have extended the standard setup to a combination of a large vacuum tank surrounded by electrical coils. The vacuum tank eliminates the air scattering and we can use the polarization analysis down to the lowest accessible momentum transfers. The coils themselves also show some new features: In contrary to the classic (symmetric) coil distribution we use an asymmetric setup which gives the advantage of a larger scattering window. Due to a more sophisticated current distribution this modified coil arrangement needs not to be rotated for different scattering conditions. The whole set-up will soon be available at IN12, a cold neutrons three-axis spectrometer operated by FZ Juelich in collaboration with CEA Grenoble as a CRG-B instrument at the Institut Laue Langevin in Grenoble

  5. Orbiting Carbon Observatory-2 (OCO-2) cloud screening algorithms; validation against collocated MODIS and CALIOP data

    Science.gov (United States)

    Taylor, T. E.; O'Dell, C. W.; Frankenberg, C.; Partain, P.; Cronk, H. Q.; Savtchenko, A.; Nelson, R. R.; Rosenthal, E. J.; Chang, A. Y.; Fisher, B.; Osterman, G.; Pollock, R. H.; Crisp, D.; Eldering, A.; Gunson, M. R.

    2015-12-01

    ≃ 85 % over four 16-day orbit repeat cycles in both the winter (December) and spring (April-May) for OCO-2 nadir-land, glint-land and glint-water observations. No major, systematic, spatial or temporal dependencies were found, although slight differences in the seasonal data sets do exist and validation is more problematic with increasing solar zenith angle and when surfaces are covered in snow and ice and have complex topography. To further analyze the performance of the cloud screening algorithms, an initial comparison of OCO-2 observations was made to collocated measurements from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) aboard the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO). These comparisons highlight the strength of the OCO-2 cloud screening algorithms in identifying high, thin clouds but suggest some difficulty in identifying some clouds near the surface, even when the optical thicknesses are greater than 1.

  6. Orbiting Carbon Observatory-2 (OCO-2) cloud screening algorithms: validation against collocated MODIS and CALIOP data

    Science.gov (United States)

    Taylor, Thomas E.; O'Dell, Christopher W.; Frankenberg, Christian; Partain, Philip T.; Cronk, Heather Q.; Savtchenko, Andrey; Nelson, Robert R.; Rosenthal, Emily J.; Chang, Albert Y.; Fisher, Brenden; Osterman, Gregory B.; Pollock, Randy H.; Crisp, David; Eldering, Annmarie; Gunson, Michael R.

    2016-03-01

    , agreement between the OCO-2 and MODIS cloud screening methods is found to be ≃ 85 % over four 16-day orbit repeat cycles in both the winter (December) and spring (April-May) for OCO-2 nadir-land, glint-land and glint-water observations.No major, systematic, spatial or temporal dependencies were found, although slight differences in the seasonal data sets do exist and validation is more problematic with increasing solar zenith angle and when surfaces are covered in snow and ice and have complex topography. To further analyze the performance of the cloud screening algorithms, an initial comparison of OCO-2 observations was made to collocated measurements from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) aboard the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO). These comparisons highlight the strength of the OCO-2 cloud screening algorithms in identifying high, thin clouds but suggest some difficulty in identifying some clouds near the surface, even when the optical thicknesses are greater than 1.

  7. MIPAS detection of cloud and aerosol particle occurrence in the UTLS with comparison to HIRDLS and CALIOP

    Directory of Open Access Journals (Sweden)

    H. Sembhi

    2012-10-01

    Full Text Available Satellite infrared emission instruments require efficient systems that can separate and flag observations which are affected by clouds and aerosols. This paper investigates the identification of cloud and aerosols from infrared, limb sounding spectra that were recorded by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS, a high spectral resolution Fourier transform spectrometer on the European Space Agency's (ESA ENVISAT (Now inoperative since April 2012 due to loss of contact. Specifically, the performance of an existing cloud and aerosol particle detection method is simulated with a radiative transfer model in order to establish, for the first time, confident detection limits for particle presence in the atmosphere from MIPAS data. The newly established thresholds improve confidence in the ability to detect particle injection events, plume transport in the upper troposphere and lower stratosphere (UTLS and better characterise cloud distributions utilising MIPAS spectra. The method also provides a fast front-end detection system for the MIPClouds processor; a processor designed for the retrieval of macro- and microphysical cloud properties from the MIPAS data.

    It is shown that across much of the stratosphere, the threshold for the standard cloud index in band A is 5.0 although threshold values of over 6.0 occur in restricted regimes. Polar regions show a surprising degree of uncertainty at altitudes above 20 km, potentially due to changing stratospheric trace gas concentrations in polar vortex conditions and poor signal-to-noise due to cold atmospheric temperatures. The optimised thresholds of this study can be used for much of the time, but time/composition-dependent thresholds are recommended for MIPAS data for the strongly perturbed polar stratosphere. In the UT, a threshold of 5.0 applies at 12 km and above but decreases rapidly at lower altitudes. The new thresholds are shown to allow much more sensitive

  8. CALIOP-based Biomass Burning Smoke Plume Injection Height

    Science.gov (United States)

    Soja, A. J.; Choi, H. D.; Fairlie, T. D.; Pouliot, G.; Baker, K. R.; Winker, D. M.; Trepte, C. R.; Szykman, J.

    2017-12-01

    Carbon and aerosols are cycled between terrestrial and atmosphere environments during fire events, and these emissions have strong feedbacks to near-field weather, air quality, and longer-term climate systems. Fire severity and burned area are under the control of weather and climate, and fire emissions have the potential to alter numerous land and atmospheric processes that, in turn, feedback to and interact with climate systems (e.g., changes in patterns of precipitation, black/brown carbon deposition on ice/snow, alteration in landscape and atmospheric/cloud albedo). If plume injection height is incorrectly estimated, then the transport and deposition of those emissions will also be incorrect. The heights to which smoke is injected governs short- or long-range transport, which influences surface pollution, cloud interaction (altered albedo), and modifies patterns of precipitation (cloud condensation nuclei). We are working with the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) science team and other stakeholder agencies, primarily the Environmental Protection Agency and regional partners, to generate a biomass burning (BB) plume injection height database using multiple platforms, sensors and models (CALIOP, MODIS, NOAA HMS, Langley Trajectory Model). These data have the capacity to provide enhanced smoke plume injection height parameterization in regional, national and international scientific and air quality models. Statistics that link fire behavior and weather to plume rise are crucial for verifying and enhancing plume rise parameterization in local-, regional- and global-scale models used for air quality, chemical transport and climate. Specifically, we will present: (1) a methodology that links BB injection height and CALIOP air parcels to specific fires; (2) the daily evolution of smoke plumes for specific fires; (3) plumes transport and deposited on the Greenland Ice Sheet; and (4) compare CALIOP-derived smoke plume injection

  9. Energetic neutral atom imaging with the Polar CEPPAD/IPS instrument: Initial forward modeling results

    International Nuclear Information System (INIS)

    Henderson, M.G.; Reeves, G.D.; Moore, K.R.; Spence, H.E.; Jorgensen, A.M.; Roelof, E.C.

    1997-01-01

    Although the primary function of the CEP-PAD/IPS instrument on Polar is the measurement of energetic ions in-situ, it has also proven to be a very capable Energetic neutral Atom (ENA) imager. Raw ENA images are currently being constructed on a routine basis with a temporal resolution of minutes during both active and quiet times. However, while analyses of these images by themselves provide much information on the spatial distribution and dynamics of the energetic ion population in the ring current, detailed modeling is required to extract the actual ion distributions. In this paper, the authors present the initial results of forward modeling an IPS ENA image obtained during a small geo-magnetic storm on June 9, 1997. The equatorial ion distribution inferred with this technique reproduces the expected large noon/midnight and dawn/dusk asymmetries. The limitations of the model are discussed and a number of modifications to the basic forward modeling technique are proposed which should significantly improve its performance in future studies

  10. Polarized neutrons

    International Nuclear Information System (INIS)

    Williams, W.G.

    1988-01-01

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

  11. New infrared solid state laser materials for CALIOPE

    International Nuclear Information System (INIS)

    DeLoach, L.D.; Page, R.H.; Wilke, G.D.

    1994-01-01

    Tunable infrared laser light may serve as a useful means by which to detect the presence of the targeted effluents. Since optical parametric oscillators (OPOs) have proven to be a versatile method of generating coherent light from the ultraviolet to the mid-infrared, this technology is a promising choice by which to service the CALIOPE applications. In addition, since some uncertainty remains regarding the precise wavelengths and molecules that will be targeted, the deployment of OPOs retains the greatest amount of wavelength flexibility. Another approach that the authors are considering is that of generating tunable infrared radiation directly with a diode-pumped solid state laser (DPSSL). One important advantage of a DPSSL is that it offers flexible pulse format modes that can be tailored to meet the needs of a particular application and target molecule. On the other hand, direct generation by a tunable DPSSL will generally be able to cover a more limited wavelength range than is possible with OPO technology. In support of the CALIOPE objectives the authors are exploring the potential for laser action among a class of materials comprised of transition metal-doped zinc chalcogenide crystals (i.e., ZnS, ZnSe and ZnTe). The Cr 2+ , Co 2+ and Ni 2+ dopants were selected as the most favorable candidates, on the basis of their documented spectral properties in the scientific literature. Thus far, the authors have characterized the absorption and emission properties of these ions in the ZnS and ZnSe crystals. The absorption spectra are used to determine the preferred wavelength at which the crystal should be pumped, while the emission spectra reveal the extent of the tuning range potentially offered by the material. In addition, measurements of the emission lifetime as a function of temperature turn out to be quite useful, since this data is suggestive of the room temperature emission yield

  12. A browser-based 3D Visualization Tool designed for comparing CERES/CALIOP/CloudSAT level-2 data sets.

    Science.gov (United States)

    Chu, C.; Sun-Mack, S.; Chen, Y.; Heckert, E.; Doelling, D. R.

    2017-12-01

    In Langley NASA, Clouds and the Earth's Radiant Energy System (CERES) and Moderate Resolution Imaging Spectroradiometer (MODIS) are merged with Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) on the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) and CloudSat Cloud Profiling Radar (CPR). The CERES merged product (C3M) matches up to three CALIPSO footprints with each MODIS pixel along its ground track. It then assigns the nearest CloudSat footprint to each of those MODIS pixels. The cloud properties from MODIS, retrieved using the CERES algorithms, are included in C3M with the matched CALIPSO and CloudSat products along with radiances from 18 MODIS channels. The dataset is used to validate the CERES retrieved MODIS cloud properties and the computed TOA and surface flux difference using MODIS or CALIOP/CloudSAT retrieved clouds. This information is then used to tune the computed fluxes to match the CERES observed TOA flux. A visualization tool will be invaluable to determine the cause of these large cloud and flux differences in order to improve the methodology. This effort is part of larger effort to allow users to order the CERES C3M product sub-setted by time and parameter as well as the previously mentioned visualization capabilities. This presentation will show a new graphical 3D-interface, 3D-CERESVis, that allows users to view both passive remote sensing satellites (MODIS and CERES) and active satellites (CALIPSO and CloudSat), such that the detailed vertical structures of cloud properties from CALIPSO and CloudSat are displayed side by side with horizontally retrieved cloud properties from MODIS and CERES. Similarly, the CERES computed profile fluxes whether using MODIS or CALIPSO and CloudSat clouds can also be compared. 3D-CERESVis is a browser-based visualization tool that makes uses of techniques such as multiple synchronized cursors, COLLADA format data and Cesium.

  13. Instrumentations in x-ray plasma polarization spectroscopy. Crystal spectrometer, polarimeter and detectors for astronomical observations

    Energy Technology Data Exchange (ETDEWEB)

    Baronova, Elena O.; Stepanenko, Mikhail M. [RRC Kurchatov Institute, Nuclear Fusion Institute, Moscow (Russian Federation); Jakubowski, Lech [Soltan Institute for Nuclear Studies, Swierk-Otwock (Poland); Tsunemi, Hiroshi [Osaka Univ., Graduate School of Science, Osaka (Japan)

    2002-08-01

    This report discusses the various problems which are encountered when a crystal spectrometer is used for the purpose of observing polarized x-ray lines. A polarimeter is proposed based on the novel idea of using two series of equivalent atomic planes in a single crystal. The present status of the astronomical x-ray detection techniques are described with emphasis on two dimensional detectors which are polarization sensitive. (author)

  14. Influence of CDOM and particle composition on ocean color of the Eastern New Caledonia Lagoon during the CALIOPE cruises

    Science.gov (United States)

    Dupouy, Cécile; Röttgers, Rüdiger; Tedetti, Marc; Martias, Chloe; Murakami, Hiroshi; Doxaran, David; Lantoine, Francois; Rodier, Martine; Favareto, Luciane; Kampel, Milton; Goutx, Madeleine; Frouin, Robert J.

    2014-11-01

    Ocean color of tropical lagoons is dependent on bathymetry and bottom type, as well as input of coastal living and mineral particles and chromophoric dissolved organic matter (CDOM). The New Caledonia lagoon lies in the Southwestern Tropical Pacific around 21° 30'S and 166° 30'E, with a great marine biodiversity in UNESCO Heritage coral reefs, benthic sea grass, and benthic communities. They are largely connected to the open ocean in the southern and eastern parts, but only by narrow passes in the southwest part. The trophic state is linked to spatial variations in flushing times. High run offs due to rain carrying abundant chromophoric dissolved organic matter (CDOM) and particle loads may greatly impact the functioning of ecosystems while rivers and sewage effluents may induce localized impacts. Two oceanographic cruises (CALIOPE 1 in 2011 and CALIOPE 2 in 2014) were carried out off the Eastern Coast of New Caledonia during a calm dry period and during high winds, respectively. Multi- and hyper-spectral marine reflectance was measured with a SIMBADA instrument and a TRIOS radiometer system, together with inherent optical properties (total and CDOM absorption coefficients with a PSICAM, in situ absorption and scattering with an AC9, backscattering with a Hydroscat-6). Fluorescence of CDOM (EEM/PARAFAC) was measured on collected 0.2 μm filtered samples. In 2014, Satlantic and FieldSpec hyper-spectral radiometers were available for in-water profiling of upwelling radiance and downwelling irradiance and above-water reflectance measurements, respectively. Inherent and apparent optical data from the two cruises are compared and used to estimate ocean color algorithms performance and evaluate a Linear Matrix Inversion method, providing tools for remote sensing on this highly under-sampled coastal region of New Caledonia.

  15. Chaos, Consternation and CALIPSO Calibration: New Strategies for Calibrating the CALIOP 1064 nm Channel

    Science.gov (United States)

    Vaughan, Mark; Garnier, Anne; Liu, Zhaoyan; Josset, Damien; Hu, Yongxiang; Lee, Kam-Pui; Hunt, William; Vernier, Jean-Paul; Rodier, Sharon; Pelon, Jaques; hide

    2012-01-01

    The very low signal-to-noise ratios of the 1064 nm CALIOP molecular backscatter signal make it effectively impossible to employ the "clear air" normalization technique typically used to calibrate elastic back-scatter lidars. The CALIPSO mission has thus chosen to cross-calibrate their 1064 nm measurements with respect to the 532 nm data using the two-wavelength backscatter from cirrus clouds. In this paper we discuss several known issues in the version 3 CALIOP 1064 nm calibration procedure, and describe the strategies that will be employed in the version 4 data release to surmount these problems.

  16. Instrumentation

    International Nuclear Information System (INIS)

    Prieur, G.; Nadi, M.; Hedjiedj, A.; Weber, S.

    1995-01-01

    This second chapter on instrumentation gives little general consideration on history and classification of instrumentation, and two specific states of the art. The first one concerns NMR (block diagram of instrumentation chain with details on the magnets, gradients, probes, reception unit). The first one concerns precision instrumentation (optical fiber gyro-meter and scanning electron microscope), and its data processing tools (programmability, VXI standard and its history). The chapter ends with future trends on smart sensors and Field Emission Displays. (D.L.). Refs., figs

  17. Decision-Making by Handball Referees: Design of an ad hoc Observation Instrument and Polar Coordinate Analysis.

    Science.gov (United States)

    Morillo, Juan P; Reigal, Rafael E; Hernández-Mendo, Antonio; Montaña, Alejandro; Morales-Sánchez, Verónica

    2017-01-01

    Referees are essential for sports such as handball. However, there are few tools available to analyze the activity of handball referees. The aim of this study was to design an instrument for observing the behavior of referees in handball competitions and to analyze the resulting data by polar coordinate analysis. The instrument contained 6 criteria and 18 categories and can be used to monitor and describe the actions of handball referees according to their role/position on the playing court. For the data quality control analysis, we calculated Pearson's (0.99), Spearman's (0.99), and Tau Kendall's (1.00) correlation coefficients and Cohen's kappa (entre 0.72 y 0.75) and Phi (entre 0.83 y 0.87) coefficients. In the generalizability analysis, the absolute and relative generalizability coefficients were 0.99 in both cases. Polar coordinate analysis of referee decisions showed that correct calls were more common for central court and 7-meter throw calls. Likewise, calls were more likely to be incorrect (in terms of both errors of omission and commission) when taken from the goal-line position.

  18. Decision-Making by Handball Referees: Design of an ad hoc Observation Instrument and Polar Coordinate Analysis

    Directory of Open Access Journals (Sweden)

    Juan P. Morillo

    2017-10-01

    Full Text Available Referees are essential for sports such as handball. However, there are few tools available to analyze the activity of handball referees. The aim of this study was to design an instrument for observing the behavior of referees in handball competitions and to analyze the resulting data by polar coordinate analysis. The instrument contained 6 criteria and 18 categories and can be used to monitor and describe the actions of handball referees according to their role/position on the playing court. For the data quality control analysis, we calculated Pearson's (0.99, Spearman's (0.99, and Tau Kendall's (1.00 correlation coefficients and Cohen's kappa (entre 0.72 y 0.75 and Phi (entre 0.83 y 0.87 coefficients. In the generalizability analysis, the absolute and relative generalizability coefficients were 0.99 in both cases. Polar coordinate analysis of referee decisions showed that correct calls were more common for central court and 7-meter throw calls. Likewise, calls were more likely to be incorrect (in terms of both errors of omission and commission when taken from the goal-line position.

  19. Instrumentation

    International Nuclear Information System (INIS)

    Decreton, M.

    2000-01-01

    SCK-CEN's research and development programme on instrumentation aims at evaluating the potentials of new instrumentation technologies under the severe constraints of a nuclear application. It focuses on the tolerance of sensors to high radiation doses, including optical fibre sensors, and on the related intelligent data processing needed to cope with the nuclear constraints. Main achievements in these domains in 1999 are summarised

  20. Instrumentation

    Energy Technology Data Exchange (ETDEWEB)

    Decreton, M

    2001-04-01

    SCK-CEN's research and development programme on instrumentation involves the assessment and the development of sensitive measurement systems used within a radiation environment. Particular emphasis is on the assessment of optical fibre components and their adaptability to radiation environments. The evaluation of ageing processes of instrumentation in fission plants, the development of specific data evaluation strategies to compensate for ageing induced degradation of sensors and cable performance form part of these activities. In 2000, particular emphasis was on in-core reactor instrumentation applied to fusion, accelerator driven and water-cooled fission reactors. This involved the development of high performance instrumentation for irradiation experiments in the BR2 reactor in support of new instrumentation needs for MYRRHA, and for diagnostic systems for the ITER reactor.

  1. Instrumentation

    International Nuclear Information System (INIS)

    Decreton, M.

    2001-01-01

    SCK-CEN's research and development programme on instrumentation involves the assessment and the development of sensitive measurement systems used within a radiation environment. Particular emphasis is on the assessment of optical fibre components and their adaptability to radiation environments. The evaluation of ageing processes of instrumentation in fission plants, the development of specific data evaluation strategies to compensate for ageing induced degradation of sensors and cable performance form part of these activities. In 2000, particular emphasis was on in-core reactor instrumentation applied to fusion, accelerator driven and water-cooled fission reactors. This involved the development of high performance instrumentation for irradiation experiments in the BR2 reactor in support of new instrumentation needs for MYRRHA, and for diagnostic systems for the ITER reactor

  2. Instrumentation

    International Nuclear Information System (INIS)

    Decreton, M.

    2002-01-01

    SCK-CEN's R and D programme on instrumentation involves the development of advanced instrumentation systems for nuclear applications as well as the assessment of the performance of these instruments in a radiation environment. Particular emphasis is on the use of optical fibres as umbilincal links of a remote handling unit for use during maintanance of a fusion reacor, studies on the radiation hardening of plasma diagnostic systems; investigations on new instrumentation for the future MYRRHA accelerator driven system; space applications related to radiation-hardened lenses; the development of new approaches for dose, temperature and strain measurements; the assessment of radiation-hardened sensors and motors for remote handling tasks and studies of dose measurement systems including the use of optical fibres. Progress and achievements in these areas for 2001 are described

  3. Instrumentation

    Energy Technology Data Exchange (ETDEWEB)

    Decreton, M

    2002-04-01

    SCK-CEN's R and D programme on instrumentation involves the development of advanced instrumentation systems for nuclear applications as well as the assessment of the performance of these instruments in a radiation environment. Particular emphasis is on the use of optical fibres as umbilincal links of a remote handling unit for use during maintanance of a fusion reacor, studies on the radiation hardening of plasma diagnostic systems; investigations on new instrumentation for the future MYRRHA accelerator driven system; space applications related to radiation-hardened lenses; the development of new approaches for dose, temperature and strain measurements; the assessment of radiation-hardened sensors and motors for remote handling tasks and studies of dose measurement systems including the use of optical fibres. Progress and achievements in these areas for 2001 are described.

  4. Instrumentation

    Energy Technology Data Exchange (ETDEWEB)

    Decreton, M

    2000-07-01

    SCK-CEN's research and development programme on instrumentation aims at evaluating the potentials of new instrumentation technologies under the severe constraints of a nuclear application. It focuses on the tolerance of sensors to high radiation doses, including optical fibre sensors, and on the related intelligent data processing needed to cope with the nuclear constraints. Main achievements in these domains in 1999 are summarised.

  5. Instrumentation

    International Nuclear Information System (INIS)

    Umminger, K.

    2008-01-01

    A proper measurement of the relevant single and two-phase flow parameters is the basis for the understanding of many complex thermal-hydraulic processes. Reliable instrumentation is therefore necessary for the interaction between analysis and experiment especially in the field of nuclear safety research where postulated accident scenarios have to be simulated in experimental facilities and predicted by complex computer code systems. The so-called conventional instrumentation for the measurement of e. g. pressures, temperatures, pressure differences and single phase flow velocities is still a solid basis for the investigation and interpretation of many phenomena and especially for the understanding of the overall system behavior. Measurement data from such instrumentation still serves in many cases as a database for thermal-hydraulic system codes. However some special instrumentation such as online concentration measurement for boric acid in the water phase or for non-condensibles in steam atmosphere as well as flow visualization techniques were further developed and successfully applied during the recent years. Concerning the modeling needs for advanced thermal-hydraulic codes, significant advances have been accomplished in the last few years in the local instrumentation technology for two-phase flow by the application of new sensor techniques, optical or beam methods and electronic technology. This paper will give insight into the current state of instrumentation technology for safety-related thermohydraulic experiments. Advantages and limitations of some measurement processes and systems will be indicated as well as trends and possibilities for further development. Aspects of instrumentation in operating reactors will also be mentioned.

  6. Reusing Joint Polar Satellite System (jpss) Ground System Components to Process AURA Ozone Monitoring Instrument (omi) Science Products

    Science.gov (United States)

    Moses, J. F.; Jain, P.; Johnson, J.; Doiron, J. A.

    2017-12-01

    New Earth observation instruments are planned to enable advancements in Earth science research over the next decade. Diversity of Earth observing instruments and their observing platforms will continue to increase as new instrument technologies emerge and are deployed as part of National programs such as Joint Polar Satellite System (JPSS), Geostationary Operational Environmental Satellite system (GOES), Landsat as well as the potential for many CubeSat and aircraft missions. The practical use and value of these observational data often extends well beyond their original purpose. The practicing community needs intuitive and standardized tools to enable quick unfettered development of tailored products for specific applications and decision support systems. However, the associated data processing system can take years to develop and requires inherent knowledge and the ability to integrate increasingly diverse data types from multiple sources. This paper describes the adaptation of a large-scale data processing system built for supporting JPSS algorithm calibration and validation (Cal/Val) node to a simplified science data system for rapid application. The new configurable data system reuses scalable JAVA technologies built for the JPSS Government Resource for Algorithm Verification, Independent Test, and Evaluation (GRAVITE) system to run within a laptop environment and support product generation and data processing of AURA Ozone Monitoring Instrument (OMI) science products. Of particular interest are the root requirements necessary for integrating experimental algorithms and Hierarchical Data Format (HDF) data access libraries into a science data production system. This study demonstrates the ability to reuse existing Ground System technologies to support future missions with minimal changes.

  7. Water Vapor, Temperature, and Ice Particles in Polar Mesosphere as Measured by SABER/TIMED and OSIRIS/Odin Instruments

    Science.gov (United States)

    Feofilov, A. G.; Petelina, S. V.; Kutepov, A. A.; Pesnell, W. D.; Goldberg, R. A.

    2009-01-01

    Although many new details on the properties of mesospheric ice particles that farm Polar Mesospheric Clouds (PMCs) and also cause polar mesospheric summer echoes have been recently revealed, certain aspects of mesospheric ice microphysics and dynamics still remain open. The detailed relation between PMC parameters and properties of their environment, as well as interseasonal and interhemispheric differences and trends in PMC properties that are possibly related to global change, are among those open questions. In this work, mesospheric temperature and water vapor concentration measured by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on board the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite are used to study the properties of PMCs with respect to the surrounding atmosphere. The cloud parameters, namely location, brightness, and altitude, are obtained from the observations made by the Optical Spectrograph and Infrared Imager System (OSIRIS) on the Odin satellite. About a thousand of simultaneous common volume measurements made by SABER and OSIRIS in both hemispheres from 2002 until 2008 are used. The correlation between PMC brightness (and occurrence rate) and temperatures at PMC altitudes and at the mesopause is analysed. The relation between PMC parameters, frost point temperature, and gaseous water vapor content in and below the cloud is also discussed. Interseasonal and interhemispheric differences and trends in the above parameters, as well as in PMC peak altitudes and mesopause altitudes are evaluated.

  8. Instruments

    International Nuclear Information System (INIS)

    Buehrer, W.

    1996-01-01

    The present paper mediates a basic knowledge of the most commonly used experimental techniques. We discuss the principles and concepts necessary to understand what one is doing if one performs an experiment on a certain instrument. (author) 29 figs., 1 tab., refs

  9. A versatile and modular quasi optics-based 200 GHz dual dynamic nuclear polarization and electron paramagnetic resonance instrument

    Science.gov (United States)

    Siaw, Ting Ann; Leavesley, Alisa; Lund, Alicia; Kaminker, Ilia; Han, Songi

    2016-03-01

    Solid-state dynamic nuclear polarization (DNP) at higher magnetic fields (>3 T) and cryogenic temperatures (∼2-90 K) has gained enormous interest and seen major technological advances as an NMR signal enhancing technique. Still, the current state of the art DNP operation is not at a state at which sample and freezing conditions can be rationally chosen and the DNP performance predicted a priori, but relies on purely empirical approaches. An important step towards rational optimization of DNP conditions is to have access to DNP instrumental capabilities to diagnose DNP performance and elucidate DNP mechanisms. The desired diagnoses include the measurement of the "DNP power curve", i.e. the microwave (MW) power dependence of DNP enhancement, the "DNP spectrum", i.e. the MW frequency dependence of DNP enhancement, the electron paramagnetic resonance (EPR) spectrum, and the saturation and spectral diffusion properties of the EPR spectrum upon prolonged MW irradiation typical of continuous wave (CW) DNP, as well as various electron and nuclear spin relaxation parameters. Even basic measurements of these DNP parameters require versatile instrumentation at high magnetic fields not commercially available to date. In this article, we describe the detailed design of such a DNP instrument, powered by a solid-state MW source that is tunable between 193 and 201 GHz and outputs up to 140 mW of MW power. The quality and pathway of the transmitted and reflected MWs is controlled by a quasi-optics (QO) bridge and a corrugated waveguide, where the latter couples the MW from an open-space QO bridge to the sample located inside the superconducting magnet and vice versa. Crucially, the versatility of the solid-state MW source enables the automated acquisition of frequency swept DNP spectra, DNP power curves, the diagnosis of MW power and transmission, and frequency swept continuous wave (CW) and pulsed EPR experiments. The flexibility of the DNP instrument centered around the QO MW

  10. A versatile and modular quasi optics-based 200GHz dual dynamic nuclear polarization and electron paramagnetic resonance instrument.

    Science.gov (United States)

    Siaw, Ting Ann; Leavesley, Alisa; Lund, Alicia; Kaminker, Ilia; Han, Songi

    2016-03-01

    Solid-state dynamic nuclear polarization (DNP) at higher magnetic fields (>3T) and cryogenic temperatures (∼ 2-90K) has gained enormous interest and seen major technological advances as an NMR signal enhancing technique. Still, the current state of the art DNP operation is not at a state at which sample and freezing conditions can be rationally chosen and the DNP performance predicted a priori, but relies on purely empirical approaches. An important step towards rational optimization of DNP conditions is to have access to DNP instrumental capabilities to diagnose DNP performance and elucidate DNP mechanisms. The desired diagnoses include the measurement of the "DNP power curve", i.e. the microwave (MW) power dependence of DNP enhancement, the "DNP spectrum", i.e. the MW frequency dependence of DNP enhancement, the electron paramagnetic resonance (EPR) spectrum, and the saturation and spectral diffusion properties of the EPR spectrum upon prolonged MW irradiation typical of continuous wave (CW) DNP, as well as various electron and nuclear spin relaxation parameters. Even basic measurements of these DNP parameters require versatile instrumentation at high magnetic fields not commercially available to date. In this article, we describe the detailed design of such a DNP instrument, powered by a solid-state MW source that is tunable between 193 and 201 GHz and outputs up to 140 mW of MW power. The quality and pathway of the transmitted and reflected MWs is controlled by a quasi-optics (QO) bridge and a corrugated waveguide, where the latter couples the MW from an open-space QO bridge to the sample located inside the superconducting magnet and vice versa. Crucially, the versatility of the solid-state MW source enables the automated acquisition of frequency swept DNP spectra, DNP power curves, the diagnosis of MW power and transmission, and frequency swept continuous wave (CW) and pulsed EPR experiments. The flexibility of the DNP instrument centered around the QO MW

  11. Instrumentation

    International Nuclear Information System (INIS)

    Muehllehner, G.; Colsher, J.G.

    1982-01-01

    This chapter reviews the parameters which are important to positron-imaging instruments. It summarizes the options which various groups have explored in designing tomographs and the methods which have been developed to overcome some of the limitations inherent in the technique as well as in present instruments. The chapter is not presented as a defense of positron imaging versus single-photon or other imaging modality, neither does it contain a description of various existing instruments, but rather stresses their common properties and problems. Design parameters which are considered are resolution, sampling requirements, sensitivity, methods of eliminating scattered radiation, random coincidences and attenuation. The implementation of these parameters is considered, with special reference to sampling, choice of detector material, detector ring diameter and shielding and variations in point spread function. Quantitation problems discussed are normalization, and attenuation and random corrections. Present developments mentioned are noise reduction through time-of-flight-assisted tomography and signal to noise improvements through high intrinsic resolution. Extensive bibliography. (U.K.)

  12. Design of a nondestructive two-in-one instrument for measuring the polarization and energy spectrum at an X-ray FEL facility

    Science.gov (United States)

    Zhang, Qingmin; Deng, Bangjie; Chen, Yuanmiaoliang; Liu, Bochao; Chen, Shaofei; Fan, Jinquan; Feng, Lie; Deng, Haixiao; Liu, Bo; Wang, Dong

    2017-10-01

    The free electron laser (FEL), as a next-generation light source, is an attractive tool in scientific frontier research because of its advantages of full coherence, ultra-short pulse duration, and controllable polarization. Owing to the demand of real-time bunch diagnosis during FEL experiments, precise nondestructive measurements of the polarization and X-ray energy spectrum using one instrument are preferred. In this paper, such an instrument based on the electron time-of-flight technique is proposed. By considering the complexity and nonlinearity, a numerical model in the framework of Geant4 has been developed for optimization. Taking the Shanghai Soft X-ray FEL user facility as an example, its measurement performances' dependence on the critical parameters was studied systematically, and, finally, an optimal design was obtained, achieving resolutions of 0.5% for the polarization degree and 0.3 eV for the X-ray energy spectrum.

  13. CALIOP: a multichannel design code for gas-cooled fast reactors. Code description and user's guide

    International Nuclear Information System (INIS)

    Thompson, W.I.

    1980-10-01

    CALIOP is a design code for fluid-cooled reactors composed of parallel fuel tubes in hexagonal or cylindrical ducts. It may be used with gaseous or liquid coolants. It has been used chiefly for design of a helium-cooled fast breeder reactor and has built-in cross section information to permit calculations of fuel loading, breeding ratio, and doubling time. Optional cross-section input allows the code to be used with moderated cores and with other fuels

  14. Biogeochemical fingerprints of life: earlier analogies with polar ecosystems suggest feasible instrumentation for probing the Galilean moons

    Science.gov (United States)

    Chela-Flores, J.; Cicuttin, A.; Crespo, M. L.; Tuniz, C.

    2015-07-01

    We base our search for the right instrumentation for detecting biosignatures on Europa on the analogy suggested by the recent work on polar ecosystems in the Canadian Arctic at Ellesmere Island. In that location sulphur patches (analogous to the Europan patches) are accumulating on glacial ice lying over saline springs rich in sulphate and sulphide. Their work reinforces earlier analogies in Antarctic ecosystems that are appropriate models for possible habitats that will be explored by the European Space Agency JUpiter ICy Moons Explorer (JUICE) mission to the Jovian System. Its Jupiter Ganymede Orbiter (JGO) will include orbits around Europa and Ganymede. The Galileo orbital mission discovered surficial patches of non-ice elements on Europa that were widespread and, in some cases possibly endogenous. This suggests the possibility that the observed chemical elements in the exoatmosphere may be from the subsurface ocean. Spatial resolution calculations of Cassidy and co-workers are available, suggesting that the atmospheric S content can be mapped by a neutral mass spectrometer, now included among the selected JUICE instruments. In some cases, large S-fractionations are due to microbial reduction and disproportionation (although sometimes providing a test for ecosystem fingerprints, even though with Sim - Bosak - Ono we maintain that microbial sulphate reduction large sulphur isotope fractionation does not require disproportionation. We address the question of the possible role of oxygen in the Europan ocean. Instrument issues are discussed for measuring stable S-isotope fractionations up to the known limits in natural populations of δ34 ~ -70‰. We state the hypothesis of a Europa anaerobic oceanic population of sulphate reducers and disproportionators that would have the effect of fractionating the sulphate that reaches the low-albedo surficial regions. This hypothesis is compatible with the time-honoured expectation of Kaplan and co-workers (going back to the

  15. Characterization of AVHRR global cloud detection sensitivity based on CALIPSO-CALIOP cloud optical thickness information: demonstration of results based on the CM SAF CLARA-A2 climate data record

    Science.gov (United States)

    Karlsson, Karl-Göran; Håkansson, Nina

    2018-02-01

    The sensitivity in detecting thin clouds of the cloud screening method being used in the CM SAF cloud, albedo and surface radiation data set from AVHRR data (CLARA-A2) cloud climate data record (CDR) has been evaluated using cloud information from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) onboard the CALIPSO satellite. The sensitivity, including its global variation, has been studied based on collocations of Advanced Very High Resolution Radiometer (AVHRR) and CALIOP measurements over a 10-year period (2006-2015). The cloud detection sensitivity has been defined as the minimum cloud optical thickness for which 50 % of clouds could be detected, with the global average sensitivity estimated to be 0.225. After using this value to reduce the CALIOP cloud mask (i.e. clouds with optical thickness below this threshold were interpreted as cloud-free cases), cloudiness results were found to be basically unbiased over most of the globe except over the polar regions where a considerable underestimation of cloudiness could be seen during the polar winter. The overall probability of detecting clouds in the polar winter could be as low as 50 % over the highest and coldest parts of Greenland and Antarctica, showing that a large fraction of optically thick clouds also remains undetected here. The study included an in-depth analysis of the probability of detecting a cloud as a function of the vertically integrated cloud optical thickness as well as of the cloud's geographical position. Best results were achieved over oceanic surfaces at mid- to high latitudes where at least 50 % of all clouds with an optical thickness down to a value of 0.075 were detected. Corresponding cloud detection sensitivities over land surfaces outside of the polar regions were generally larger than 0.2 with maximum values of approximately 0.5 over the Sahara and the Arabian Peninsula. For polar land surfaces the values were close to 1 or higher with maximum values of 4.5 for the parts

  16. The Research on the Spectral Characteristics of Sea Fog Based on Caliop and Modis Data

    Science.gov (United States)

    Wan, J.; Su, J.; Liu, S.; Sheng, H.

    2018-04-01

    In view of that difficulty of distinguish between sea fog and low cloud by optical remote sensing mean, the research on spectral characteristics of sea fog is focused and carried out. The satellite laser radar CALIOP data and the high spectral MODIS data were obtained from May to December 2017, and the scattering coefficient and the vertical height information were extracted from the atmospheric attenuation of the lower star to extract the sea fog sample points, and the spectral response curve based on MODIS was formed to analyse the spectral response characteristics of the sea fog, thus providing a theoretical basis for the monitoring of sea fog with optical remote sensing image.

  17. A method for determination of cirrus extinction-to-backscatter ratio from CALIOP data

    Directory of Open Access Journals (Sweden)

    Zhang Jingbin

    2016-01-01

    Full Text Available We are presenting an empirical equation to retrieve cirrus lidar ratio by using CALIOP 532 nm level 1 data for nighttime cases. Retrieval results have non-relationship with cirrus multiple scattering effects and not affected by the error of transmission. The average CALIPSO 532 nm cirrus lidar ratio over Longitude 120+/- 10 and Latitude 25+/-10 for whole year of 2008 are 21.66±0.06sr for the year of 2008 respectively, with the maximum bias of 9.25% for the year 2008, the results is fairly stable and reasonable.

  18. IR detectors for the Infrared Atmospheric Sounding Interferometer (IASI) instrument payload for the METOP-1 ESA polar platform

    Science.gov (United States)

    Royer, Michel; Lorans, Dominique; Bischoff, Isabelle; Giotta, Dominique; Wolny, Michel

    1994-12-01

    IASI is an Infrared Atmospheric Sounding Interferometer devoted to the operational meteorology and to atmospheric studies and is to be installed on board the second ESA Polar Platform called METOP-1, planned to be launched in the year 2000. The main purpose of this high performance instrument is to record temperature and humidity profiles. The required lifetime is 4 years. This paper presents the characteristics of the LW IR detection arrays for the IASI spectrometer which consist of HgCdTe de- tectors. SAT has to develop the Engineering Model, Qualification Model and Fight Models of detectors, each having 4 pixels and AR-coated microlenses in a dedicated space housing equipped with a flexible line and a connector. An array is composed of HgCdTe photoconductive detectors. For this long wavelength the array is sensitive from 8.26 micrometers to 15.5 micrometers . The detectors, with sensitive areas of 900 x 900 micrometers 2, are 100 K operating with passive cooling. High quality HgCdTe material is a key feature for the manufacturing of high performance photoconductive detectors. Therefore epitaxial HgCdTe layers are used in this project. These epilayers are grown at CEA/LETI on lattice matched CdZnTe substrates, by Te-rich liquid phase epitaxy, based on a slider technique. The Cd content in the layer is carefully adjusted to meet the required cut off wavelength on the devices. After growth of the epilayers, the samples are annealed under Hg pressure in order to convert them into N type mate- rials. The electrical transport properties of the liquid phase epitaxied wafers are, at 100 K, mobility (mu) over 150,000 cm2/V.s and electrical concentration N of 1.5 1015 cm-3, the residual doping level being 1014 cm-3 at low temperature. On these materials the feasibility study of long wavelength HgCdTe photoconductors has been achieved with the following results: the responsivity is 330 V/W. The bias voltage is Vp=300 mV for a 4 mW limitation of power for each element. The

  19. Polarized BRDF measurement of steel E235B in the near-infrared region: Based on a self-designed instrument with absolute measuring method

    Science.gov (United States)

    Liu, Yanlei; Yu, Kun; Liu, Zilong; Zhao, Yuejin; Liu, Yufang

    2018-06-01

    The spectral bidirectional reflectance distribution (BRDF) offers a complete description of the optical properties of the opaque material. Numerous studies on BRDF have been conducted for its important role in scientific research and industrial production. However, most of these studies focus on the visible region and unpolarized BRDF, and the spectral polarized BRDF in the near-infrared region is rarely reported. In this letter, we propose an absolute method to measure the spectral BRDF in the near-infrared region, and the detailed derivation is presented. A self-designed instrument is set up for the absolute measurement of BRDF. The reliability of this method is verified by comparing the experimental data of the three metal (aluminum, silver and gold) mirrors with the reference data. The in-plane polarized BRDF of steel E235B are measured, and the influence of incident angle and roughness on the BRDF are discussed. The degree of linear polarization (DOLP) are determined based on the polarized BRDF. The results indicate that both the roughness and incident angle have distinct influence on the BRDF and DOLP.

  20. Characteristics of Volcanic Stratospheric Aerosol Layer Observed by CALIOP and Ground Based Lidar at Equatorial Atmosphere Radar Site

    Science.gov (United States)

    Abo, Makoto; Shibata, Yasukuni; Nagasawa, Chikao

    2018-04-01

    We investigated the relation between major tropical volcanic eruptions in the equatorial region and the stratospheric aerosol data, which have been collected by the ground based lidar observations at at Equatorial Atmosphere Radar site between 2004 and 2015 and the CALIOP observations in low latitude between 2006 and 2015. We found characteristic dynamic behavior of volcanic stratospheric aerosol layers over equatorial region.

  1. Macrophysical and optical properties of midlatitude cirrus clouds from four ground-based lidars and collocated CALIOP observations

    Energy Technology Data Exchange (ETDEWEB)

    Dupont, Jean-Charles; Haeffelin, M.; Morille, Y.; Noel, V.; Keckhut, P.; Winker, D.; Comstock, Jennifer M.; Chervet, P.; Roblin, A.

    2010-05-27

    Ground-based lidar and CALIOP datasets gathered over four mid-latitude sites, two US and two French sites, are used to evaluate the consistency of cloud macrophysical and optical property climatologies that can be derived by such datasets. The consistency in average cloud height (both base and top height) between the CALIOP and ground datasets ranges from -0.4km to +0.5km. The cloud geometrical thickness distributions vary significantly between the different datasets, due in part to the original vertical resolutions of the lidar profiles. Average cloud geometrical thicknesses vary from 1.2 to 1.9km, i.e. by more than 50%. Cloud optical thickness distributions in subvisible, semi-transparent and moderate intervals differ by more than 50% between ground and space-based datasets. The cirrus clouds with 2 optical thickness below 0.1 (not included in historical cloud climatologies) represent 30-50% of the non-opaque cirrus class. The differences in average cloud base altitude between ground and CALIOP datasets of 0.0-0.1 km, 0.0-0.2 km and 0.0-0.2 km can be attributed to irregular sampling of seasonal variations in the ground-based data, to day-night differences in detection capabilities by CALIOP, and to the restriction to situations without low-level clouds in ground-based data, respectively. The cloud geometrical thicknesses are not affected by irregular sampling of seasonal variations in the ground-based data, while up to 0.0-0.2 km and 0.1-0.3 km differences can be attributed to day-night differences in detection capabilities by CALIOP, and to the restriction to situations without lowlevel clouds in ground-based data, respectively.

  2. LAP-ND: a new instrument for vector polarization analysis and neutron depolarization measurements at FRJ-2

    International Nuclear Information System (INIS)

    Ioffe, Alexander; Bussmann, Klaus; Dohmen, Ludwig; Axelrod, Leonid; Gordeev, Gennadi; Brueckel, Thomas

    2004-01-01

    The method of vector analysis of the neutron polarization allows for the determination of both the magnitude and the direction of the magnetization vector in the sample. A directional distribution of the magnetization in a sample results in a spread of the direction of the polarization vector in space and thus in the depolarization of the incident beam. A new neutron depolarization set up is installed at the research reactor FRJ-2 of the Forschungszentrum Juelich. The main feature of the set up is the use of rather long wavelength, λ=(4-6.5) A, neutrons thus allowing for a significant increase in the sensitivity of depolarization measurements. The set up uses a non-cryogenic zero-field sample chamber with the residual magnetic field of about 1 mG. It will be used for the determination of the sample magnetization at mesoscopic and macroscopic levels and for the study of magnetic phase transitions, magnetic nanostructures, magnetic glasses, etc

  3. Instrumentation for cryogenic magic angle spinning dynamic nuclear polarization using 90L of liquid nitrogen per day.

    Science.gov (United States)

    Albert, Brice J; Pahng, Seong Ho; Alaniva, Nicholas; Sesti, Erika L; Rand, Peter W; Saliba, Edward P; Scott, Faith J; Choi, Eric J; Barnes, Alexander B

    2017-10-01

    Cryogenic sample temperatures can enhance NMR sensitivity by extending spin relaxation times to improve dynamic nuclear polarization (DNP) and by increasing Boltzmann spin polarization. We have developed an efficient heat exchanger with a liquid nitrogen consumption rate of only 90L per day to perform magic-angle spinning (MAS) DNP experiments below 85K. In this heat exchanger implementation, cold exhaust gas from the NMR probe is returned to the outer portion of a counterflow coil within an intermediate cooling stage to improve cooling efficiency of the spinning and variable temperature gases. The heat exchange within the counterflow coil is calculated with computational fluid dynamics to optimize the heat transfer. Experimental results using the novel counterflow heat exchanger demonstrate MAS DNP signal enhancements of 328±3 at 81±2K, and 276±4 at 105±2K. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. LAP-ND: a new instrument for vector polarization analysis and neutron depolarization measurements at FRJ-2

    Energy Technology Data Exchange (ETDEWEB)

    Ioffe, Alexander; Bussmann, Klaus; Dohmen, Ludwig; Axelrod, Leonid; Gordeev, Gennadi; Brueckel, Thomas

    2004-07-15

    The method of vector analysis of the neutron polarization allows for the determination of both the magnitude and the direction of the magnetization vector in the sample. A directional distribution of the magnetization in a sample results in a spread of the direction of the polarization vector in space and thus in the depolarization of the incident beam. A new neutron depolarization set up is installed at the research reactor FRJ-2 of the Forschungszentrum Juelich. The main feature of the set up is the use of rather long wavelength, {lambda}=(4-6.5) A, neutrons thus allowing for a significant increase in the sensitivity of depolarization measurements. The set up uses a non-cryogenic zero-field sample chamber with the residual magnetic field of about 1 mG. It will be used for the determination of the sample magnetization at mesoscopic and macroscopic levels and for the study of magnetic phase transitions, magnetic nanostructures, magnetic glasses, etc.

  5. Aerosol Indirect Effect on Warm Clouds over Eastern China Using Combined CALIOP and MODIS Observations

    Science.gov (United States)

    Guo, Jianping; Wang, Fu; Huang, Jingfeng; Li, Xiaowen

    2015-04-01

    Aerosol, one of key components of the climate system, is highly variable, both temporally and spatially. It often exerts great influences on the cloud-precipitation chain processes by serving as CCN/IN, altering cloud microphysics and its life cycle. Yet, the aerosol indirect effect on clouds remains largely unknown, because the initial changes in clouds due to aerosols may be enhanced or dampened by such feedback processes as modified cloud dynamics, or evaporation of the smaller droplets due to the competition for water vapor. In this study, we attempted to quantify the aerosol effects on warm cloud over eastern China, based on near-simultaneous retrievals from MODIS/AQUA, CALIOP/CALIPSO and CPR/CLOUDSAT during the period 2006 to 2010. The seasonality of aerosol from ground-based PM10 is quite different from that estimated from MODIS AOD. This result is corroborated by lower level profile of aerosol occurrence frequency from CALIOP, indicating the significant role CALIOP could play in aerosol-cloud interaction. The combined use of CALIOP and CPR facilitate the process to exactly determine the (vertical) position of warm cloud relative to aerosol, out of six scenarios in terms of aerosol-cloud mixing status in terms of aerosol-cloud mixing status, which shows as follows: AO (Aerosol only), CO (Cloud only), SASC (Single aerosol-single cloud), SADC (single aerosol-double cloud), DASC (double aerosol-single cloud), and others. Results shows that about 54% of all the cases belong to mixed status, among all the collocated aerosol-cloud cases. Under mixed condition, a boomerang shape is observed, i.e., reduced cloud droplet radius (CDR) is associated with increasing aerosol at moderate aerosol pollution (AODcases. We categorize dataset into warm-season and cold-season subsets to figure out how the boomerang shape varies with season. For moderate aerosol loading (AODMixed" cases is greater during cold season (denoted by a large slope), as compared with that during warm

  6. THE RESEARCH ON THE SPECTRAL CHARACTERISTICS OF SEA FOG BASED ON CALIOP AND MODIS DATA

    Directory of Open Access Journals (Sweden)

    J. Wan

    2018-04-01

    Full Text Available In view of that difficulty of distinguish between sea fog and low cloud by optical remote sensing mean, the research on spectral characteristics of sea fog is focused and carried out。The satellite laser radar CALIOP data and the high spectral MODIS data were obtained from May to December 2017, and the scattering coefficient and the vertical height information were extracted from the atmospheric attenuation of the lower star to extract the sea fog sample points, and the spectral response curve based on MODIS was formed to analyse the spectral response characteristics of the sea fog, thus providing a theoretical basis for the monitoring of sea fog with optical remote sensing image.

  7. Some Technical Aspects of a CALIOP and MODIS Data Analysis that Examines Near-Cloud Aerosol Properties as a Function of Cloud Fraction

    Science.gov (United States)

    Varnai, Tamas; Yang, Weidong; Marshak, Alexander

    2016-01-01

    CALIOP shows stronger near-cloud changes in aerosol properties at higher cloud fractions. Cloud fraction variations explain a third of near-cloud changes in overall aerosol statistics. Cloud fraction and aerosol particle size distribution have a complex relationship.

  8. Cloud Statistics and Discrimination in the Polar Regions

    Science.gov (United States)

    Chan, M.; Comiso, J. C.

    2012-12-01

    Despite their important role in the climate system, cloud cover and their statistics are poorly known, especially in the polar regions, where clouds are difficult to discriminate from snow covered surfaces. The advent of the A-train, which included Aqua/MODIS, CALIPSO/CALIOP and CloudSat/CPR sensors has provided an opportunity to improve our ability to accurately characterize the cloud cover. MODIS provides global coverage at a relatively good temporal and spatial resolution while CALIOP and CPR provide limited nadir sampling but accurate characterization of the vertical structure and phase of the cloud cover. Over the polar regions, cloud detection from a passive sensors like MODIS is challenging because of the presence of cold and highly reflective surfaces such as snow, sea-ice, glaciers, and ice-sheet, which have surface signatures similar to those of clouds. On the other hand, active sensors such as CALIOP and CPR are not only very sensitive to the presence of clouds but can also provide information about its microphysical characteristics. However, these nadir-looking sensors have sparse spatial coverage and their global data can have data spatial gaps of up to 100 km. We developed a polar cloud detection system for MODIS that is trained using collocated data from CALIOP and CPR. In particular, we employ a machine learning system that reads the radiative profile observed by MODIS and determine whether the field of view is cloudy or clear. Results have shown that the improved cloud detection scheme performs better than typical cloud mask algorithms using a validation data set not used for training. A one-year data set was generated and results indicate that daytime cloud detection accuracies improved from 80.1% to 92.6% (over sea-ice) and 71.2% to 87.4% (over ice-sheet) with CALIOP data used as the baseline. Significant improvements are also observed during nighttime, where cloud detection accuracies increase by 19.8% (over sea-ice) and 11.6% (over ice

  9. A new method based on low background instrumental neutron activation analysis for major, trace and ultra-trace element determination in atmospheric mineral dust from polar ice cores

    Energy Technology Data Exchange (ETDEWEB)

    Baccolo, Giovanni, E-mail: giovanni.baccolo@mib.infn.it [Graduate School in Polar Sciences, University of Siena, Via Laterina 8, 53100, Siena (Italy); Department of Environmental Sciences, University of Milano-Bicocca, P.zza della Scienza 1, 20126, Milano (Italy); INFN, Section of Milano-Bicocca, P.zza della Scienza 3, 20126, Milano (Italy); Clemenza, Massimiliano [INFN, Section of Milano-Bicocca, P.zza della Scienza 3, 20126, Milano (Italy); Department of Physics, University of Milano-Bicocca, P.zza della Scienza 3, 20126, Milano (Italy); Delmonte, Barbara [Department of Environmental Sciences, University of Milano-Bicocca, P.zza della Scienza 1, 20126, Milano (Italy); Maffezzoli, Niccolò [Centre for Ice and Climate, Niels Bohr Institute, Juliane Maries Vej, 30, 2100, Copenhagen (Denmark); Nastasi, Massimiliano; Previtali, Ezio [INFN, Section of Milano-Bicocca, P.zza della Scienza 3, 20126, Milano (Italy); Department of Physics, University of Milano-Bicocca, P.zza della Scienza 3, 20126, Milano (Italy); Prata, Michele; Salvini, Andrea [LENA, University of Pavia, Pavia (Italy); Maggi, Valter [Department of Environmental Sciences, University of Milano-Bicocca, P.zza della Scienza 1, 20126, Milano (Italy); INFN, Section of Milano-Bicocca, P.zza della Scienza 3, 20126, Milano (Italy)

    2016-05-30

    Dust found in polar ice core samples present extremely low concentrations, in addition the availability of such samples is usually strictly limited. For these reasons the chemical and physical analysis of polar ice cores is an analytical challenge. In this work a new method based on low background instrumental neutron activation analysis (LB-INAA) for the multi-elemental characterization of the insoluble fraction of dust from polar ice cores is presented. Thanks to an accurate selection of the most proper materials and procedures it was possible to reach unprecedented analytical performances, suitable for ice core analyses. The method was applied to Antarctic ice core samples. Five samples of atmospheric dust (μg size) from ice sections of the Antarctic Talos Dome ice core were prepared and analyzed. A set of 37 elements was quantified, spanning from all the major elements (Na, Mg, Al, Si, K, Ca, Ti, Mn and Fe) to trace ones, including 10 (La, Ce, Nd, Sm, Eu, Tb, Ho, Tm, Yb and Lu) of the 14 natural occurring lanthanides. The detection limits are in the range of 10{sup −13}–10{sup −6} g, improving previous results of 1–3 orders of magnitude depending on the element; uncertainties lies between 4% and 60%. - Highlights: • A new method based on neutron activation for the multi-elemental characterization of atmospheric dust entrapped in polar ice cores is proposed. • 37 elements were quantified in μg size dust samples with detection limits ranging from 10{sup −13} to 10{sup −6} g. • A low background approach and a clean analytical protocol improved INAA performances to unprecedented levels for multi-elemental analyses.

  10. Stand-alone polarization-modulation infrared reflection absorption spectroscopy instrument optimized for the study of catalytic processes at elevated pressures

    Science.gov (United States)

    Kestell, John D.; Mudiyanselage, Kumudu; Ye, Xinyi; Nam, Chang-Yong; Stacchiola, Dario; Sadowski, Jerzy; Boscoboinik, J. Anibal

    2017-10-01

    This paper describes the design and construction of a compact, "user-friendly" polarization-modulation infrared reflection absorption spectroscopy (PM-IRRAS) instrument at the Center for Functional Nanomaterials (CFN) of Brookhaven National Laboratory, which allows studying surfaces at pressures ranging from ultra-high vacuum to 100 Torr. Surface infrared spectroscopy is ideally suited for studying these processes as the vibrational frequencies of the IR chromophores are sensitive to the nature of the bonding environment on the surface. Relying on the surface selection rules, by modulating the polarization of incident light, it is possible to separate the contributions from the isotropic gas or solution phase, from the surface bound species. A spectral frequency range between 1000 cm-1 and 4000 cm-1 can be acquired. While typical spectra with a good signal to noise ratio can be obtained at elevated pressures of gases in ˜2 min at 4 cm-1 resolution, we have also acquired higher resolution spectra at 0.25 cm-1 with longer acquisition times. By way of verification, CO uptake on a heavily oxidized Ru(0001) sample was studied. As part of this test study, the presence of CO adsorbed on Ru bridge sites was confirmed, in agreement with previous ambient pressure X ray photoelectron spectroscopy studies. In terms of instrument performance, it was also determined that the gas phase contribution from CO could be completely removed even up to pressures close to 100 Torr. A second test study demonstrated the use of the technique for studying morphological properties of a spin coated polymer on a conductive surface. Note that this is a novel application of this technique. In this experiment, the polarization of incident light was modulated manually (vs. through a photoelastic modulator). It was demonstrated, in good agreement with the literature, that the polymer chains preferentially lie parallel with the surface. This PM-IRRAS system is small, modular, and easily

  11. Evaluation of spatio-temporal variability of Hamburg Aerosol Climatology against aerosol datasets from MODIS and CALIOP

    Directory of Open Access Journals (Sweden)

    V. Pappas

    2013-08-01

    Full Text Available The new global aerosol climatology named HAC (Hamburg Aerosol Climatology is compared against MODIS (Collection 5, 2000–2007 and CALIOP (Level 2-version 3, 2006–2011 retrievals. The comparison of aerosol optical depth (AOD from HAC against MODIS shows larger HAC AOD values over regions with higher aerosol loads and smaller HAC AOD values than MODIS for regions with lower loads. The HAC data are found to be more reliable over land and for low AOD values. The largest differences between HAC and MODIS occur from March to August for the Northern Hemisphere and from September to February for the Southern Hemisphere. In addition, both the spectral variability and vertical distribution of the HAC AOD are examined at selected AERONET (1998–2007 sites, representative of main aerosol types (pollutants, sea salt, biomass and dust. Based on comparisons against spectral AOD values from AERONET, the mean absolute percentage error in HAC AOD data is 25% at ultraviolet wavelengths (400 nm, 6–12% at visible and 18% at near-infrared (1000 nm. For the same AERONET sites, the HAC AOD vertical distribution is compared against CALIOP space lidar data. On a daily average basis, HAD AOD is less by 9% in the lowest 3 km than CALIOP values, especially for sites with biomass burning smoke, desert dust and sea salt spray. Above the boundary layer, the HAC AOD vertical distribution is reliable.

  12. De-coupling interannual variations of vertical dust extinction over the Taklimakan Desert during 2007-2016 using CALIOP.

    Science.gov (United States)

    Nan, Yang; Wang, Yuxuan

    2018-03-26

    During the springtime, mineral dust from the Taklimakan Desert (TD) is lifted up to high altitudes and transported long distances by the westerlies. The vertical distributions of Taklimakan dust are important for both long-range transport and climate effects. In this study, we use CALIOP Level 3 dust extinction to describe interannual variation of dust extinction in TD aggregated at each 1km interval (1-2km, 2-3km, 3-4km, 4-5km and 5-6km) above mean sea level during springtime from 2007 to 2016. 87% of dust extinction over TD is concentrated at 1-4km taking a major composition of dust aerosol optical depth (AOD) and only 8.1% dust AOD is at 4-6km. Interannual variation of seasonal and monthly dust extinction at 1-4km is almost as same as dust AOD (R>0.99) but different from that at 4-6km (R are around 0.42). Our analysis provides observational evidence from CALIOP that vertical dust extinction over TD has distinctively different variability below and above 4km altitude and this threshold divides dust transport in TD into two systems. Taklimakan dust aerosols are more related to dust transport at high altitudes (4-10km) than low altitudes (0-4km) over downwind regions. High dust extinction below 4km over TD is necessary but not sufficient conditions to ensure dust transport easterly, while high dust extinction levels at 4-6km over TD are both necessary and sufficient conditions; such contrast leads to the de-coupled interannual variability seen by CALIOP. Copyright © 2018 Elsevier B.V. All rights reserved.

  13. A Novel Method for Estimating Shortwave Direct Radiative Effect of Above-Cloud Aerosols Using CALIOP and MODIS Data

    Science.gov (United States)

    Zhang, Z.; Meyer, K.; Platnick, S.; Oreopoulos, L.; Lee, D.; Yu, H.

    2014-01-01

    This paper describes an efficient and unique method for computing the shortwave direct radiative effect (DRE) of aerosol residing above low-level liquid-phase clouds using CALIOP and MODIS data. It accounts for the overlapping of aerosol and cloud rigorously by utilizing the joint histogram of cloud optical depth and cloud top pressure. Effects of sub-grid scale cloud and aerosol variations on DRE are accounted for. It is computationally efficient through using grid-level cloud and aerosol statistics, instead of pixel-level products, and a pre-computed look-up table in radiative transfer calculations. We verified that for smoke over the southeast Atlantic Ocean the method yields a seasonal mean instantaneous shortwave DRE that generally agrees with more rigorous pixel-level computation within 4. We have also computed the annual mean instantaneous shortwave DRE of light-absorbing aerosols (i.e., smoke and polluted dust) over global ocean based on 4 yr of CALIOP and MODIS data. We found that the variability of the annual mean shortwave DRE of above-cloud light-absorbing aerosol is mainly driven by the optical depth of the underlying clouds.

  14. Inter-comparison between Hermesv2.0 and TNO-MAC-II emission data using the Caliope air quality system (Spain)

    NARCIS (Netherlands)

    Guevara, M.; Pay, M.T.; Martinez, F.; Soret, A.; Denier van der Gon, H.A.C.; Baldasano, J.M.

    2014-01-01

    This work examines and compares the performance of two emission datasets on modelling air quality concentrations for Spain: (i) the High-Elective Resolution Modelling Emissions System (HERMESv2.0) and (ii) the TNO-MACC-II emission inventory. For this purpose, the air quality system CALIOPE-AQFS

  15. Instrumental aspects

    Directory of Open Access Journals (Sweden)

    Qureshi Navid

    2017-01-01

    Full Text Available Every neutron scattering experiment requires the choice of a suited neutron diffractometer (or spectrometer in the case of inelastic scattering with its optimal configuration in order to accomplish the experimental tasks in the most successful way. Most generally, the compromise between the incident neutron flux and the instrumental resolution has to be considered, which is depending on a number of optical devices which are positioned in the neutron beam path. In this chapter the basic instrumental principles of neutron diffraction will be explained. Examples of different types of experiments and their respective expectable results will be shown. Furthermore, the production and use of polarized neutrons will be stressed.

  16. Modeling of 2008 Kasatochi Volcanic Sulfate Direct Radiative Forcing: Assimilation of OMI SO2 Plume Height Data and Comparison with MODIS and CALIOP Observations

    Science.gov (United States)

    Wang, J.; Park, S.; Zeng, J.; Ge, C.; Yang, K.; Carn, S.; Krotkov, N.; Omar, A. H.

    2013-01-01

    Volcanic SO2 column amount and injection height retrieved from the Ozone Monitoring Instrument (OMI) with the Extended Iterative Spectral Fitting (EISF) technique are used to initialize a global chemistry transport model (GEOS-Chem) to simulate the atmospheric transport and lifecycle of volcanic SO2 and sulfate aerosol from the 2008 Kasatochi eruption, and to subsequently estimate the direct shortwave, top-of-the-atmosphere radiative forcing of the volcanic sulfate aerosol. Analysis shows that the integrated use of OMI SO2 plume height in GEOS-Chem yields: (a) good agreement of the temporal evolution of 3-D volcanic sulfate distributions between model simulations and satellite observations from the Moderate Resolution Imaging Spectroradiometer (MODIS) and Cloud-Aerosol Lidar with Orthogonal Polarisation (CALIOP), and (b) an e-folding time for volcanic SO2 that is consistent with OMI measurements, reflecting SO2 oxidation in the upper troposphere and stratosphere is reliably represented in the model. However, a consistent (approx. 25 %) low bias is found in the GEOS-Chem simulated SO2 burden, and is likely due to a high (approx.20 %) bias of cloud liquid water amount (as compared to the MODIS cloud product) and the resultant stronger SO2 oxidation in the GEOS meteorological data during the first week after eruption when part of SO2 underwent aqueous-phase oxidation in clouds. Radiative transfer calculations show that the forcing by Kasatochi volcanic sulfate aerosol becomes negligible 6 months after the eruption, but its global average over the first month is -1.3W/sq m, with the majority of the forcing-influenced region located north of 20degN, and with daily peak values up to -2W/sq m on days 16-17. Sensitivity experiments show that every 2 km decrease of SO2 injection height in the GEOS-Chem simulations will result in a approx.25% decrease in volcanic sulfate forcing; similar sensitivity but opposite sign also holds for a 0.03 m increase of geometric radius of

  17. Modulation of cosmic microwave background polarization with a warm rapidly rotating half-wave plate on the Atacama B-Mode Search instrument.

    Science.gov (United States)

    Kusaka, A; Essinger-Hileman, T; Appel, J W; Gallardo, P; Irwin, K D; Jarosik, N; Nolta, M R; Page, L A; Parker, L P; Raghunathan, S; Sievers, J L; Simon, S M; Staggs, S T; Visnjic, K

    2014-02-01

    We evaluate the modulation of cosmic microwave background polarization using a rapidly rotating, half-wave plate (HWP) on the Atacama B-Mode Search. After demodulating the time-ordered-data (TOD), we find a significant reduction of atmospheric fluctuations. The demodulated TOD is stable on time scales of 500-1000 s, corresponding to frequencies of 1-2 mHz. This facilitates recovery of cosmological information at large angular scales, which are typically available only from balloon-borne or satellite experiments. This technique also achieves a sensitive measurement of celestial polarization without differencing the TOD of paired detectors sensitive to two orthogonal linear polarizations. This is the first demonstration of the ability to remove atmospheric contamination at these levels from a ground-based platform using a rapidly rotating HWP.

  18. OSIRIS (Observing System Including PolaRisation in the Solar Infrared Spectrum) instrument: a multi-directional, polarized radiometer in the visible and shortwave infrared, airborne prototype of 3MI / EPS-SG Eumetsat - ESA mission

    Science.gov (United States)

    Matar, C.; Auriol, F.; Nicolas, J. M.; Parol, F.; Riedi, J.; Djellali, M. S.; Cornet, C.; Waquet, F.; Catalfamo, M.; Delegove, C.; Loisil, R.

    2017-12-01

    OSIRIS instrument largely inherits from the POLDER concept developed and operated between 1991 (first airborne prototype) and 2013 (end of the POLDER-3/PARASOL space-borne mission). It consists in two optical systems, one covering the visible to near infrared range (440, 490, 670, 763, 765, 870, 910 and 940 nm) and a second one for the shortwave infrared (940, 1020, 1240, 1360, 1620 and 2200 nm). Each optical system is composed of a wide field-of-view optics (114° and 105° respectively) associated to two rotating wheels with interferential filters (spectral) and analyzers filters (polarization) respectively, and a 2D array of detectors. For each channel, radiance is measured once without analyzer, followed by sequential measurements with the three analyzers shifted by an angle of 60° to reconstruct the total and polarized radiances. The complete acquisition sequence for all spectral channels last a couple of seconds according to the chosen measurement protocol. Thanks to the large field of view of the optics, any target is seen under several viewing angles during the aircraft motion. In a first step we will present the new ground characterization of the instrument based on laboratory measurements (linearity, flat-field, absolute calibration, induced polarization, polarizers efficiency and position), the radiometric model and the Radiometric Inverted Model (RIM) used to develop the Level 1 processing chain that is used to produce level 1 products (normalized radiances, polarized or not, with viewing geometries) from the instrument generated level 0 files (Digital Counts) and attitude information from inertial system. The stray light issues will be specifically discussed. In a second step we will present in-flight radiometric and geometric methods applied to OSIRIS data in order to control and validate ground-based calibrated products: molecular scattering method and sun-glint cross-band method for radiometric calibration, glories, rainbows and sun-glint targets

  19. Airborne Laser Polarization Sensor

    Science.gov (United States)

    Kalshoven, James, Jr.; Dabney, Philip

    1991-01-01

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

  20. Air quality over Europe and Iberian Peninsula for 2004 at high horizontal resolution: evaluation of the CALIOPE modelling system

    Science.gov (United States)

    Jorba, O.; Piot, M.; Pay, M. T.; Jiménez-Guerrero, P.; López, E.; Pérez, C.; Gassó, S.; Baldasano, J. M.

    2009-09-01

    In the frame of the CALIOPE project (Baldasano et al., 2008a), a high-resolution air quality forecasting system, WRF-ARW/HERMES/CMAQ/DREAM, is under development and applied to the European domain (12km x 12km, 1hr) as well as to the Iberian Peninsula domain (4km x 4km, 1hr) to provide air quality forecasts for Spain (http://www.bsc.es/caliope/). The simulation of such high-resolution model system is possible by its implementation on the MareNostrum supercomputer. To reassure potential users and reduce uncertainties, the model system must be evaluated to assess its performances in terms of air quality levels and dynamics reproducibility. The present contribution describes a thorough quantitative evaluation study performed for a reference year (2004). CALIOPE is a complex system that integrates a variety of environmental models. WRF-ARW provides high-resolution meteorological fields to the system. It is configured with 38 vertical layers reaching up to 50 hPa. Meteorological initial and boundary conditions are obtained from the NCEP final analysis data. The HERMES emission model (Baldasano et al., 2008b) computes the emissions for the Iberian Peninsula simulation at 4 km horizontal resolution every hour using a bottom-up approach. For the European domain, HERMES disaggregates the EMEP expert emission inventory for 2004. The CMAQ chemical transport model solves the physico-chemical processes in the system. The vertical resolution of CMAQ for gas-phase and aerosols has been increased from 8 to 15 layers in order to simulate vertical exchanges more accurately. Chemical boundary conditions are provided by the LMDz-INCA2 global climate-chemistry model (see Hauglustaine et al., 2004). Finally, the DREAM model simulates long-range transport of mineral dust over the domains under study. In order to evaluate the performances of the CALIOPE system, model simulations were compared with ground-based measurements from the EMEP and Spanish air quality networks. For the European

  1. A 3-D evaluation of the MACC reanalysis dust product over the greater European region using CALIOP/CALIPSO satellite observations

    Science.gov (United States)

    Georgoulias, Aristeidis K.; Tsikerdekis, Athanasios; Amiridis, Vassilis; Marinou, Eleni; Benedetti, Angela; Zanis, Prodromos; Kourtidis, Konstantinos

    2016-04-01

    Significant amounts of dust are being transferred on an annual basis over the Mediterranean Basin and continental Europe from Northern Africa (Sahara Desert) and Middle East (Arabian Peninsula) as well as from other local sources. Dust affects a number of processes in the atmosphere modulating weather and climate also having an impact on human health and the economy. Therefore, the ability of simulating adequately the amount and optical properties of dust is essential. This work focuses on the evaluation of the MACC reanalysis dust product over the regions mentioned above. The evaluation procedure is based on pure dust satellite retrievals from CALIOP/CALIPSO that cover the period 2007-2012. The CALIOP/CALIPSO data utilized here come from an optimized retrieval scheme that was originally developed within the framework of the LIVAS (Lidar Climatology of Vertical Aerosol Structure for Space-Based LIDAR Simulation Studies) project. CALIOP/CALIPSO dust extinction coefficients and dust optical depth patterns at 532 nm are used for the validation of MACC natural aerosol extinction coefficients and dust optical depth patterns at 550 nm. Overall, it is shown in this work that space-based lidars may play a major role in the improvement of the MACC aerosol product. This research has been financed under the FP7 Programme MarcoPolo (Grand Number 606953, Theme SPA.2013.3.2-01).

  2. Polarized light and optical measurement

    CERN Document Server

    Clarke, D N; Ter Haar, D

    2013-01-01

    Polarized Light and Optical Measurement is a five-chapter book that begins with a self-consistent conceptual picture of the phenomenon of polarization. Chapter 2 describes a number of interactions of light and matter used in devising optical elements in polarization studies. Specific optical elements are given in Chapter 3. The last two chapters explore the measurement of the state of polarization and the various roles played in optical instrumentation by polarization and polarization-sensitive elements. This book will provide useful information in this field of interest for research workers,

  3. A full year evaluation of the CALIOPE-EU air quality modeling system over Europe for 2004

    Science.gov (United States)

    Pay, M. T.; Piot, M.; Jorba, O.; Gassó, S.; Gonçalves, M.; Basart, S.; Dabdub, D.; Jiménez-Guerrero, P.; Baldasano, J. M.

    The CALIOPE-EU high-resolution air quality modeling system, namely WRF-ARW/HERMES-EMEP/CMAQ/BSC-DREAM8b, is developed and applied to Europe (12 km × 12 km, 1 h). The model performances are tested in terms of air quality levels and dynamics reproducibility on a yearly basis. The present work describes a quantitative evaluation of gas phase species (O 3, NO 2 and SO 2) and particulate matter (PM2.5 and PM10) against ground-based measurements from the EMEP (European Monitoring and Evaluation Programme) network for the year 2004. The evaluation is based on statistics. Simulated O 3 achieves satisfactory performances for both daily mean and daily maximum concentrations, especially in summer, with annual mean correlations of 0.66 and 0.69, respectively. Mean normalized errors are comprised within the recommendations proposed by the United States Environmental Protection Agency (US-EPA). The general trends and daily variations of primary pollutants (NO 2 and SO 2) are satisfactory. Daily mean concentrations of NO 2 correlate well with observations (annual correlation r = 0.67) but tend to be underestimated. For SO 2, mean concentrations are well simulated (mean bias = 0.5 μg m -3) with relatively high annual mean correlation ( r = 0.60), although peaks are generally overestimated. The dynamics of PM2.5 and PM10 is well reproduced (0.49 Deficiencies in particulate matter source characterization are discussed. Also, the spatially distributed statistics and the general patterns for each pollutant over Europe are examined. The model performances are compared with other European studies. While O 3 statistics generally remain lower than those obtained by the other considered studies, statistics for NO 2, SO 2, PM2.5 and PM10 present higher scores than most models.

  4. Spatial distribution analysis of the OMI aerosol layer height: a pixel-by-pixel comparison to CALIOP observations

    Science.gov (United States)

    Chimot, Julien; Pepijn Veefkind, J.; Vlemmix, Tim; Levelt, Pieternel F.

    2018-04-01

    A global picture of atmospheric aerosol vertical distribution with a high temporal resolution is of key importance not only for climate, cloud formation, and air quality research studies but also for correcting scattered radiation induced by aerosols in absorbing trace gas retrievals from passive satellite sensors. Aerosol layer height (ALH) was retrieved from the OMI 477 nm O2 - O2 band and its spatial pattern evaluated over selected cloud-free scenes. Such retrievals benefit from a synergy with MODIS data to provide complementary information on aerosols and cloudy pixels. We used a neural network approach previously trained and developed. Comparison with CALIOP aerosol level 2 products over urban and industrial pollution in eastern China shows consistent spatial patterns with an uncertainty in the range of 462-648 m. In addition, we show the possibility to determine the height of thick aerosol layers released by intensive biomass burning events in South America and Russia from OMI visible measurements. A Saharan dust outbreak over sea is finally discussed. Complementary detailed analyses show that the assumed aerosol properties in the forward modelling are the key factors affecting the accuracy of the results, together with potential cloud residuals in the observation pixels. Furthermore, we demonstrate that the physical meaning of the retrieved ALH scalar corresponds to the weighted average of the vertical aerosol extinction profile. These encouraging findings strongly suggest the potential of the OMI ALH product, and in more general the use of the 477 nm O2 - O2 band from present and future similar satellite sensors, for climate studies as well as for future aerosol correction in air quality trace gas retrievals.

  5. Spatial distribution analysis of the OMI aerosol layer height: a pixel-by-pixel comparison to CALIOP observations

    Directory of Open Access Journals (Sweden)

    J. Chimot

    2018-04-01

    Full Text Available A global picture of atmospheric aerosol vertical distribution with a high temporal resolution is of key importance not only for climate, cloud formation, and air quality research studies but also for correcting scattered radiation induced by aerosols in absorbing trace gas retrievals from passive satellite sensors. Aerosol layer height (ALH was retrieved from the OMI 477 nm O2 − O2 band and its spatial pattern evaluated over selected cloud-free scenes. Such retrievals benefit from a synergy with MODIS data to provide complementary information on aerosols and cloudy pixels. We used a neural network approach previously trained and developed. Comparison with CALIOP aerosol level 2 products over urban and industrial pollution in eastern China shows consistent spatial patterns with an uncertainty in the range of 462–648 m. In addition, we show the possibility to determine the height of thick aerosol layers released by intensive biomass burning events in South America and Russia from OMI visible measurements. A Saharan dust outbreak over sea is finally discussed. Complementary detailed analyses show that the assumed aerosol properties in the forward modelling are the key factors affecting the accuracy of the results, together with potential cloud residuals in the observation pixels. Furthermore, we demonstrate that the physical meaning of the retrieved ALH scalar corresponds to the weighted average of the vertical aerosol extinction profile. These encouraging findings strongly suggest the potential of the OMI ALH product, and in more general the use of the 477 nm O2 − O2 band from present and future similar satellite sensors, for climate studies as well as for future aerosol correction in air quality trace gas retrievals.

  6. Shortwave Direct Radiative Effects of Above-Cloud Aerosols Over Global Oceans Derived From 8 Years of CALIOP and MODIS Observations

    Science.gov (United States)

    Zhang, Zhibo; Meyer, Kerry; Yu, Hongbin; Platnick, Steven; Colarco, Peter; Liu, Zhaoyan; Oraiopoulos, Lazaros

    2016-01-01

    In this paper, we studied the frequency of occurrence and shortwave direct radiative effects (DREs) of above-cloud aerosols (ACAs) over global oceans using 8 years (2007-2014) of collocated CALIOP and MODIS observations. Similar to previous work, we found high ACA occurrence in four regions: southeastern (SE) Atlantic region, where ACAs are mostly light-absorbing aerosols, i.e., smoke and polluted dust according to CALIOP classification, originating from biomass burning over the African Savanna; tropical northeastern (TNE) Atlantic and the Arabian Sea, where ACAs are predominantly windblown dust from the Sahara and Arabian deserts, respectively; and the northwestern (NW) Pacific, where ACAs are mostly transported smoke and polluted dusts from Asia. From radiative transfer simulations based on CALIOP-MODIS observations and a set of the preselected aerosol optical models, we found the DREs of ACAs at the top of atmosphere (TOA) to be positive (i.e., warming) in the SE Atlantic and NW Pacific regions, but negative (i.e., cooling) in the TNE Atlantic Ocean and the Arabian Sea. The cancellation of positive and negative regional DREs results in a global ocean annual mean diurnally averaged cloudy-sky DRE of 0.015 W m(exp. -2) [range of -0.03 to 0.06 W m (exp. -2)] at TOA. The DREs at surface and within the atmosphere are -0.015 W m(exp. -2) [range of -0.09 to -0.21 W m(exp. -2)], and 0.17 W m(exp. -2) [range of 0.11 to 0.24 W m(exp. -2)], respectively. The regional and seasonal mean DREs are much stronger. For example, in the SE Atlantic region, the JJA (July-August) seasonal mean cloudy-sky DRE is about 0.7 W m(exp. -2) [range of 0.2 to 1.2 W m(exp. -2)] at TOA. All our DRE computations are publicly available. The uncertainty in our DRE computations is mainly caused by the uncertainties in the aerosol optical properties, in particular aerosol absorption, the uncertainties in the CALIOP operational aerosol optical thickness retrieval, and the ignorance of cloud and

  7. NMR dispersion measurement of dynamic nuclear polarization

    International Nuclear Information System (INIS)

    Davies, K.; Cox, S.F.J.

    1978-01-01

    The feasibility of monitoring dynamic nuclear polarization from the NMR dispersive susceptibility is examined. Two prototype instruments are tested in a polarized proton target using organic target material. The more promising employs a tunnel diode oscillator, inside the target cavity, and should provide a precise polarization measurement working at a frequency far enough from the main resonance for the disturbance of the measured polarization to be negligible. Other existing methods for measuring target polarization are briefly reviewed. (author)

  8. Caliope: an operational air quality forecasting system for the Iberian Peninsula, Balearic Islands and Canary Islands - first annual evaluation and ongoing developments

    Science.gov (United States)

    Baldasano, J. M.; Jiménez-Guerrero, P.; Jorba, O.; Pérez, C.; López, E.; Güereca, P.; Martín, F.; Vivanco, M. G.; Palomino, I.; Querol, X.; Pandolfi, M.; Sanz, M. J.; Diéguez, J. J.

    2008-05-01

    The Caliope project funded by the Spanish Ministry of the Environment establishes an air quality forecasting system for Spain to increase the knowledge on transport and dynamics of pollutants in Spain, to assure the accomplishment of legislation and to inform the population about the levels of pollutants, topics in which the European Commission has shown a great concern. The present contribution describes the first quantitative verification study performed so far with two chemistry transport models (CMAQ and CHIMERE) for a reference year (2004) at medium spatial resolution (around 20×20 km for the Iberian Peninsula). Both models perform similarly in the case of ground-level ozone. The mean normalised gross error MNGE remains below 15-20% during summertime, when ozone episodes occur, outlining the good skills of the system concerning the forecasting of air quality in Spain. Furthermore, the ongoing developments of the system towards high resolution modelling (4×4 km for Spain, 12×12 km for Europe, 1 h temporal resolution) and the integration with observations within the Caliope umbrella are described.

  9. A Novel Method for Estimating Shortwave Direct Radiative Effect of Above-cloud Aerosols over Ocean Using CALIOP and MODIS Data

    Science.gov (United States)

    Zhang, Z.; Meyer, K.; Platnick, S.; Oreopoulos, L.; Lee, D.; Yu, H.

    2013-01-01

    This paper describes an efficient and unique method for computing the shortwave direct radiative effect (DRE) of aerosol residing above low-level liquid-phase clouds using CALIOP and MODIS data. It accounts for the overlapping of aerosol and cloud rigorously by utilizing the joint histogram of cloud optical depth and cloud top pressure. Effects of sub-grid scale cloud and aerosol variations on DRE are accounted for. It is computationally efficient through using grid-level cloud and aerosol statistics, instead of pixel-level products, and a pre-computed look-up table in radiative transfer calculations. We verified that for smoke over the southeast Atlantic Ocean the method yields a seasonal mean instantaneous shortwave DRE that generally agrees with more rigorous pixel-level computation within 4%. We have also computed the annual mean instantaneous shortwave DRE of light-absorbing aerosols (i.e., smoke and polluted dust) over global ocean based on 4 yr of CALIOP and MODIS data. We found that the variability of the annual mean shortwave DRE of above-cloud light-absorbing aerosol is mainly driven by the optical depth of the underlying clouds.

  10. Primordial Inflation Polarization Explorer: Status and Plans

    Science.gov (United States)

    Kogut, Alan

    2009-01-01

    The Primordial Inflation Polarization Explorer is a balloon-borne instrument to measure the polarization of the cosmic microwave background in order to detect the characteristic signature of gravity waves created during an inflationary epoch in the early universe. PIPER combines cold /I.G K\\ optics, 5120 bolometric detectors, and rapid polarization modulation using VPM grids to achieve both high sensitivity and excellent control of systematic errors. I will discuss the current status and plans for the PIPER instrument.

  11. Polarization developments

    International Nuclear Information System (INIS)

    Prescott, C.Y.

    1993-07-01

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

  12. VIIRS-J1 Polarization Narrative

    Science.gov (United States)

    Waluschka, Eugene; McCorkel, Joel; McIntire, Jeff; Moyer, David; McAndrew, Brendan; Brown, Steven W.; Lykke, Keith; Butler, James; Meister, Gerhard; Thome, Kurtis J.

    2015-01-01

    The VIS/NIR bands polarization sensitivity of Joint Polar Satellite Sensor 1 (JPSS1) Visible/Infrared Imaging Radiometer Suite (VIIRS) instrument was measured using a broadband source. While polarization sensitivity for bands M5-M7, I1, and I2 was less than 2.5%, the maximum polarization sensitivity for bands M1, M2, M3, and M4 was measured to be 6.4%, 4.4%, 3.1%, and 4.3%, respectively with a polarization characterization uncertainty of less than 0.3%. A detailed polarization model indicated that the large polarization sensitivity observed in the M1 to M4 bands was mainly due to the large polarization sensitivity introduced at the leading and trailing edges of the newly manufactured VISNIR bandpass focal plane filters installed in front of the VISNIR detectors. This was confirmed by polarization measurements of bands M1 and M4 bands using monochromatic light. Discussed are the activities leading up to and including the instruments two polarization tests, some discussion of the polarization model and the model results, the role of the focal plane filters, the polarization testing of the Aft-Optics-Assembly, the testing of the polarizers at Goddard and NIST and the use of NIST's T-SIRCUS for polarization testing and associated analyses and results.

  13. Measuring fluorescence polarization with a dichrometer.

    Science.gov (United States)

    Sutherland, John C

    2017-09-01

    A method for obtaining fluorescence polarization data from an instrument designed to measure circular and linear dichroism is compared with a previously reported approach. The new method places a polarizer between the sample and a detector mounted perpendicular to the direction of the incident beam and results in determination of the fluorescence polarization ratio, whereas the previous method does not use a polarizer and yields the fluorescence anisotropy. A similar analysis with the detector located axially with the excitation beam demonstrates that there is no frequency modulated signal due to fluorescence polarization in the absence of a polarizer. Copyright © 2017. Published by Elsevier Inc.

  14. Design and construction of the POLAR detector

    OpenAIRE

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

    2017-01-01

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

  15. A climatology of polar stratospheric cloud composition between 2002 and 2012 based on MIPAS/Envisat observations

    Science.gov (United States)

    Spang, Reinhold; Hoffmann, Lars; Müller, Rolf; Grooß, Jens-Uwe; Tritscher, Ines; Höpfner, Michael; Pitts, Michael; Orr, Andrew; Riese, Martin

    2018-04-01

    The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) instrument aboard the European Space Agency (ESA) Envisat satellite operated from July 2002 to April 2012. The infrared limb emission measurements provide a unique dataset of day and night observations of polar stratospheric clouds (PSCs) up to both poles. A recent classification method for PSC types in infrared (IR) limb spectra using spectral measurements in different atmospheric window regions has been applied to the complete mission period of MIPAS. The method uses a simple probabilistic classifier based on Bayes' theorem with a strong independence assumption on a combination of a well-established two-colour ratio method and multiple 2-D probability density functions of brightness temperature differences. The Bayesian classifier distinguishes between solid particles of ice, nitric acid trihydrate (NAT), and liquid droplets of supercooled ternary solution (STS), as well as mixed types. A climatology of MIPAS PSC occurrence and specific PSC classes has been compiled. Comparisons with results from the classification scheme of the spaceborne lidar Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) on the Cloud-Aerosol-Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite show excellent correspondence in the spatial and temporal evolution for the area of PSC coverage (APSC) even for each PSC class. Probability density functions of the PSC temperature, retrieved for each class with respect to equilibrium temperature of ice and based on coincident temperatures from meteorological reanalyses, are in accordance with the microphysical knowledge of the formation processes with respect to temperature for all three PSC types.This paper represents unprecedented pole-covering day- and nighttime climatology of the PSC distributions and their composition of different particle types. The dataset allows analyses on the temporal and spatial development of the PSC formation process over

  16. A climatology of polar stratospheric cloud composition between 2002 and 2012 based on MIPAS/Envisat observations

    Directory of Open Access Journals (Sweden)

    R. Spang

    2018-04-01

    Full Text Available The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS instrument aboard the European Space Agency (ESA Envisat satellite operated from July 2002 to April 2012. The infrared limb emission measurements provide a unique dataset of day and night observations of polar stratospheric clouds (PSCs up to both poles. A recent classification method for PSC types in infrared (IR limb spectra using spectral measurements in different atmospheric window regions has been applied to the complete mission period of MIPAS. The method uses a simple probabilistic classifier based on Bayes' theorem with a strong independence assumption on a combination of a well-established two-colour ratio method and multiple 2-D probability density functions of brightness temperature differences. The Bayesian classifier distinguishes between solid particles of ice, nitric acid trihydrate (NAT, and liquid droplets of supercooled ternary solution (STS, as well as mixed types. A climatology of MIPAS PSC occurrence and specific PSC classes has been compiled. Comparisons with results from the classification scheme of the spaceborne lidar Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP on the Cloud-Aerosol-Lidar and Infrared Pathfinder Satellite Observations (CALIPSO satellite show excellent correspondence in the spatial and temporal evolution for the area of PSC coverage (APSC even for each PSC class. Probability density functions of the PSC temperature, retrieved for each class with respect to equilibrium temperature of ice and based on coincident temperatures from meteorological reanalyses, are in accordance with the microphysical knowledge of the formation processes with respect to temperature for all three PSC types.This paper represents unprecedented pole-covering day- and nighttime climatology of the PSC distributions and their composition of different particle types. The dataset allows analyses on the temporal and spatial development of the PSC formation

  17. Neutron polarization

    International Nuclear Information System (INIS)

    Firk, F.W.K.

    1976-01-01

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

  18. Polarization holography

    DEFF Research Database (Denmark)

    Nikolova, L.; Ramanujam, P.S.

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

  19. Polarized neutron scattering on HYSPEC: the HYbrid SPECtrometer at SNS

    Energy Technology Data Exchange (ETDEWEB)

    Zaliznyak, Igor [Brookhaven National Laboratory (BNL); Savici, Andrei T [ORNL; Garlea, Vasile O [ORNL; Winn, Barry L [ORNL; Schneelock, John [Brookhaven National Laboratory (BNL); Tranquada, John M. [Brookhaven National Laboratory (BNL); Gu, G. D. [Brookhaven National Laboratory (BNL); Wang, Aifeng [Brookhaven National Laboratory (BNL); Petrovic, C [Brookhaven National Laboratory (BNL)

    2017-01-01

    We describe some of the first polarized neutron scattering measurements performed at HYSPEC spectrometer at the Spallation Neutron Source, Oak Ridge National Laboratory. We discuss details of the instrument setup and the experimental procedures in the mode with the full polarization analysis. Examples of the polarized neutron diffraction and the polarized inelastic neutron data obtained on single crystal samples are presented.

  20. Polarized neutron scattering on HYSPEC: the HYbrid SPECtrometer at SNS

    OpenAIRE

    Zaliznyak, Igor A; Savici, Andrei T.; Garlea, V. Ovidiu; Winn, Barry; Filges, Uwe; Schneeloch, John; Tranquada, John M.; Gu, Genda; Wang, Aifeng; Petrovic, Cedomir

    2016-01-01

    We describe some of the first polarized neutron scattering measurements performed at HYSPEC spectrometer at the Spallation Neutron Source, Oak Ridge National Laboratory. We discuss details of the instrument setup and the experimental procedures in the mode with full polarization analysis. Examples of polarized neutron diffraction and polarized inelastic neutron data obtained on single crystal samples are presented.

  1. Assessment of the CALIPSO Lidar 532 nm attenuated backscatter calibration using the NASA LaRC airborne High Spectral Resolution Lidar

    Directory of Open Access Journals (Sweden)

    R. R. Rogers

    2011-02-01

    Full Text Available The Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP instrument on the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO spacecraft has provided global, high-resolution vertical profiles of aerosols and clouds since it became operational on 13 June 2006. On 14 June 2006, the NASA Langley Research Center (LaRC High Spectral Resolution Lidar (HSRL was deployed aboard the NASA Langley B-200 aircraft for the first of a series of 86 underflights of the CALIPSO satellite to provide validation measurements for the CALIOP data products. To better assess the range of conditions under which CALIOP data products are produced, these validation flights were conducted under both daytime and nighttime lighting conditions, in multiple seasons, and over a large range of latitudes and aerosol and cloud conditions. This paper presents a quantitative assessment of the CALIOP 532 nm calibration (through the 532 nm total attenuated backscatter using internally calibrated airborne HSRL underflight data and is the most extensive study of CALIOP 532 nm calibration. Results show that HSRL and CALIOP 532 nm total attenuated backscatter agree on average within 2.7% ± 2.1% (CALIOP lower at night and within 2.9% ± 3.9% (CALIOP lower during the day, demonstrating the accuracy of the CALIOP 532 nm calibration algorithms. Additionally, comparisons with HSRL show consistency of the CALIOP calibration before and after the laser switch in 2009 as well as improvements in the daytime version 3.01 calibration scheme compared with the version 2 calibration scheme. Potential biases and uncertainties in the methodology relevant to validating satellite lidar measurements with an airborne lidar system are discussed and found to be less than 4.5% ± 3.2% for this validation effort with HSRL. Results from this study are also compared with prior assessments of the CALIOP 532 nm attenuated backscatter calibration.

  2. Evaluating the CALIOPE air quality modelling system: dynamics and chemistry over Europe and Iberian Peninsula for 2004 at high horizontal resolution

    Science.gov (United States)

    Piot, M.; Pay, M. T.; Jorba, O.; Baldasano, J. M.; Jiménez-Guerrero, P.; López, E.; Pérez, C.; Gassó, S.

    2009-04-01

    Often in Europe, population exposure to air pollution exceeds standards set by the EU and the World Health Organization (WHO). Urban/suburban areas are predominantly impacted upon, although exceedances of particulate matter (PM10 and PM2.5) and Ozone (O3) also take place in rural areas. In the frame of the CALIOPE project (Baldasano et al., 2008a), a high-resolution air quality forecasting system, WRF-ARW/HERMES/CMAQ/DREAM, has been developed and applied to the European domain (12km x 12km, 1hr) as well as to the Iberian Peninsula domain (4km x 4km, 1hr) to provide air quality forecasts for Spain (http://www.bsc.es/caliope/). The simulation of such high-resolution model system has been made possible by its implementation on the MareNostrum supercomputer. To reassure potential users and reduce uncertainties, the model system must be evaluated to assess its performances in terms of air quality levels and dynamics reproducibility. The present contribution describes a thorough quantitative evaluation study performed for a reference year (2004). The CALIOPE modelling system is configured with 38 vertical layers reaching up to 50 hPa for the meteorological core. Atmospheric initial and boundary conditions are obtained from the NCEP final analysis data. The vertical resolution of the CMAQ chemistry-transport model for gas-phase and aerosols has been increased from 8 to 15 layers in order to simulate vertical exchanges more accurately. Gas phase boundary conditions are provided by the LMDz-INCA2 global climate-chemistry model (see Hauglustaine et al., 2004). The DREAM model simulates long-range transport of mineral dust over the domains under study. For the European simulation, emissions are disaggregated from the EMEP expert emission inventory for 2004 to the utilized resolution using the criteria implemented in the HERMES emission model (Baldasano et al., 2008b). The HERMES model system, using a bottom-up approach, was adopted to estimate emissions for the Iberian

  3. Ionic polarization

    International Nuclear Information System (INIS)

    Mahan, G.D.

    1992-01-01

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

  4. Polarization experiments

    International Nuclear Information System (INIS)

    Halzen, F.

    1977-02-01

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

  5. Polarization measurement for internal polarized gaseous targets

    International Nuclear Information System (INIS)

    Ye Zhenyu; Ye Yunxiu; Lv Haijiang; Mao Yajun

    2004-01-01

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

  6. Recent advance in polar seismology: Global impact of the International Polar Year

    Science.gov (United States)

    Kanao, Masaki; Zhao, Dapeng; Wiens, Douglas A.; Stutzmann, Éléonore

    2015-03-01

    The most exciting initiative for the recent polar studies was the International Polar Year (IPY) in 2007-2008. The IPY has witnessed a growing community of seismologists who have made considerable efforts to acquire high-quality data in polar regions. It also provided an excellent opportunity to make significant advances in seismic instrumentation of the polar regions to achieve scientific targets involving global issues. Taking these aspects into account, we organize and publish a special issue in Polar Science on the recent advance in polar seismology and cryoseismology as fruitful achievements of the IPY.

  7. Radioisotope instruments

    CERN Document Server

    Cameron, J F; Silverleaf, D J

    1971-01-01

    International Series of Monographs in Nuclear Energy, Volume 107: Radioisotope Instruments, Part 1 focuses on the design and applications of instruments based on the radiation released by radioactive substances. The book first offers information on the physical basis of radioisotope instruments; technical and economic advantages of radioisotope instruments; and radiation hazard. The manuscript then discusses commercial radioisotope instruments, including radiation sources and detectors, computing and control units, and measuring heads. The text describes the applications of radioisotop

  8. Sources of polarized neutrons

    International Nuclear Information System (INIS)

    Walter, L.

    1983-01-01

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

  9. Design and construction of the POLAR detector

    Science.gov (United States)

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

    2018-01-01

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

  10. Instrumental interaction

    OpenAIRE

    Luciani , Annie

    2007-01-01

    International audience; The expression instrumental interaction as been introduced by Claude Cadoz to identify a human-object interaction during which a human manipulates a physical object - an instrument - in order to perform a manual task. Classical examples of instrumental interaction are all the professional manual tasks: playing violin, cutting fabrics by hand, moulding a paste, etc.... Instrumental interaction differs from other types of interaction (called symbolic or iconic interactio...

  11. Polarization study

    International Nuclear Information System (INIS)

    Nurushev, S.B.

    1989-01-01

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

  12. Polar Stratigraphy

    Science.gov (United States)

    1999-01-01

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

  13. North Polar Cap

    Science.gov (United States)

    2004-01-01

    [figure removed for brevity, see original site] This week we will be looking at five examples of laminar wind flow on the north polar cap. On Earth, gravity-driven south polar cap winds are termed 'catabatic' winds. Catabatic winds begin over the smooth expanse of the cap interior due to temperature differences between the atmosphere and the surface. Once begun, the winds sweep outward along the surface of the polar cap toward the sea. As the polar surface slopes down toward sealevel, the wind speeds increase. Catabatic wind speeds in the Antartic can reach several hundreds of miles per hour. In the images of the Martian north polar cap we can see these same type of winds. Notice the streamers of dust moving downslope over the darker trough sides, these streamers show the laminar flow regime coming off the cap. Within the trough we see turbulent clouds of dust, kicked up at the trough base as the winds slow down and enter a chaotic flow regime. The horizontal lines in these images are due to framelet overlap and lighting conditions over the bright polar cap. Image information: VIS instrument. Latitude 86.5, Longitude 64.5 East (295.5 West). 40 meter/pixel resolution. Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen

  14. Advanced optical instruments technology

    Science.gov (United States)

    Shao, Mike; Chrisp, Michael; Cheng, Li-Jen; Eng, Sverre; Glavich, Thomas; Goad, Larry; Jones, Bill; Kaarat, Philip; Nein, Max; Robinson, William

    1992-08-01

    The science objectives for proposed NASA missions for the next decades push the state of the art in sensitivity and spatial resolution over a wide range of wavelengths, including the x-ray to the submillimeter. While some of the proposed missions are larger and more sensitive versions of familiar concepts, such as the next generation space telescope, others use concepts, common on the Earth, but new to space, such as optical interferometry, in order to provide spatial resolutions impossible with other concepts. However, despite their architecture, the performance of all of the proposed missions depends critically on the back-end instruments that process the collected energy to produce scientifically interesting outputs. The Advanced Optical Instruments Technology panel was chartered with defining technology development plans that would best improve optical instrument performance for future astrophysics missions. At this workshop the optical instrument was defined as the set of optical components that reimage the light from the telescope onto the detectors to provide information about the spatial, spectral, and polarization properties of the light. This definition was used to distinguish the optical instrument technology issues from those associated with the telescope, which were covered by a separate panel. The panel identified several areas for optical component technology development: diffraction gratings; tunable filters; interferometric beam combiners; optical materials; and fiber optics. The panel also determined that stray light suppression instruments, such as coronagraphs and nulling interferometers, were in need of general development to support future astrophysics needs.

  15. The effects of different footprint sizes and cloud algorithms on the top-of-atmosphere radiative flux calculation from the Clouds and Earth's Radiant Energy System (CERES instrument on Suomi National Polar-orbiting Partnership (NPP

    Directory of Open Access Journals (Sweden)

    W. Su

    2017-10-01

    Full Text Available Only one Clouds and Earth's Radiant Energy System (CERES instrument is onboard the Suomi National Polar-orbiting Partnership (NPP and it has been placed in cross-track mode since launch; it is thus not possible to construct a set of angular distribution models (ADMs specific for CERES on NPP. Edition 4 Aqua ADMs are used for flux inversions for NPP CERES measurements. However, the footprint size of NPP CERES is greater than that of Aqua CERES, as the altitude of the NPP orbit is higher than that of the Aqua orbit. Furthermore, cloud retrievals from the Visible Infrared Imaging Radiometer Suite (VIIRS and the Moderate Resolution Imaging Spectroradiometer (MODIS, which are the imagers sharing the spacecraft with NPP CERES and Aqua CERES, are also different. To quantify the flux uncertainties due to the footprint size difference between Aqua CERES and NPP CERES, and due to both the footprint size difference and cloud property difference, a simulation is designed using the MODIS pixel-level data, which are convolved with the Aqua CERES and NPP CERES point spread functions (PSFs into their respective footprints. The simulation is designed to isolate the effects of footprint size and cloud property differences on flux uncertainty from calibration and orbital differences between NPP CERES and Aqua CERES. The footprint size difference between Aqua CERES and NPP CERES introduces instantaneous flux uncertainties in monthly gridded NPP CERES measurements of less than 4.0 W m−2 for SW (shortwave and less than 1.0 W m−2 for both daytime and nighttime LW (longwave. The global monthly mean instantaneous SW flux from simulated NPP CERES has a low bias of 0.4 W m−2 when compared to simulated Aqua CERES, and the root-mean-square (RMS error is 2.2 W m−2 between them; the biases of daytime and nighttime LW flux are close to zero with RMS errors of 0.8 and 0.2 W m−2. These uncertainties are within the uncertainties of CERES ADMs

  16. TREFF: Reflectometer and instrument component test beamline at MLZ

    Directory of Open Access Journals (Sweden)

    Peter Link

    2017-11-01

    Full Text Available TREFF is a high resolution polarized neutron reflectometer and instrument component test beamline resulting in a highly modular instrument providing a flexible beam line for various applications.

  17. CMB polarization at large angular scales: Data analysis of the POLAR experiment

    International Nuclear Information System (INIS)

    O'Dell, Christopher W.; Keating, Brian G.; Oliveira-Costa, Angelica de; Tegmark, Max; Timbie, Peter T.

    2003-01-01

    The coming flood of cosmic microwave background (CMB) polarization experiments, spurred by the recent detection of CMB polarization by the DASI and WMAP instruments, will be confronted by many new analysis tasks specific to polarization. For the analysis of CMB polarization data sets, the devil is truly in the details. With this in mind, we present details of the data analysis for the POLAR experiment, which recently led to the tightest upper limits on the polarization of the cosmic microwave background radiation at large angular scales. We discuss the data selection process, map-making algorithms, offset removal, and likelihood analysis which were used to find upper limits on the polarization. Stated using the modern convention for reporting CMB Stokes parameters, these limits are 5.0 μK on both E- and B-type polarization at 95% confidence. Finally, we discuss simulations used to test our analysis techniques and to probe the fundamental limitations of the experiment

  18. Time-of-flight and vector polarization analysis for diffuse neutron scattering

    International Nuclear Information System (INIS)

    Schweika, W.

    2003-01-01

    The potential of pulsed neutron sources for diffuse scattering including time-of-flight (TOF) and polarization analysis is discussed in comparison to the capabilities of the present instrument diffuse neutron scattering at the research center Juelich. We present first results of a new method for full polarization analysis using precessing neutron polarization. A proposal is made for a new type of instrument at pulsed sources, which allows for vector polarization analysis in TOF instruments with multi-detectors

  19. Instrumentation Facility

    Data.gov (United States)

    Federal Laboratory Consortium — Provides instrumentation support for flight tests of prototype weapons systems using a vast array of airborne sensors, transducers, signal conditioning and encoding...

  20. The Evaluation of the Spanish Air Quality Modelling System: CALIOPE. Dynamics and Chemistry over Europe and Iberian Peninsula for 2004 at high horizontal resolution

    Science.gov (United States)

    Piot, M.; Pay, M.; Jorba, O.; Lopez, E.; Pirez, C.; Gasso, S.; Baldasano, J. M.

    2009-12-01

    In Europe, human exposure to air pollution often exceeds standards set by the EU commission (Directives 1996/62/EC, 2002/3/EC, 2008/50/EC) and the World Health Organization (WHO). Urban/suburban areas are predominantly impacted upon, although exceedances of particulate matter (PM10 and PM2.5) and Ozone (O3) also take place in rural areas. Within the CALIOPE project, a high-resolution air quality forecasting system, namely WRF-ARW/HERMES04/CMAQ/BSC-DREAM, has been developed and applied to the European domain (12x12 sq. km, 1hr) as well as the Spanish domain (4x4 sq. km, 1hr). The simulation of such high-resolution model system has been made possible by its implementation on the MareNostrum supercomputer. This contribution describes a thorough quantitative evaluation study performed for the reference year 2004. The WRF-ARW meteorological model contains 38 vertical layers reaching up to 50 hPa. The vertical resolution of the CMAQ chemistry-transport model for gas-phase and aerosols has been increased from 8 to 15 layers in order to simulate vertical exchanges more accurately. Gas phase boundary conditions are provided by the LMDz-INCA2 global climate-chemistry model. For the European simulation, emissions are disaggregated from the EMEP emission inventory for 2004 to the utilized resolution using the criteria implemented in the HERMES04 emission model. The HERMES04 model system, running through a bottom-up approach, is used to estimate emissions for Spain at a 1x1 sq. km horizontal resolution, every hour. In order to evaluate the performances of the CALIOPE system, the model simulation for Europe was compared with ground-based measurements from the EMEP and the Spanish air quality networks (total of 60 stations for O3, 43 for NO2, 31 for SO2, 25 for PM10 and 16 for PM2.5). The model simulation for Europe satisfactorily reproduces O3 concentrations throughout the year (annual correlation: 0.66) with relatively small errors: MNGE values range from 13% to 26%, and MNBE

  1. Polar Polygons

    Science.gov (United States)

    2005-01-01

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

  2. Observing the Cosmic Microwave Background Polarization with Variable-delay Polarization Modulators for the Cosmology Large Angular Scale Surveyor

    Science.gov (United States)

    Harrington, Kathleen; CLASS Collaboration

    2018-01-01

    The search for inflationary primordial gravitational waves and the optical depth to reionization, both through their imprint on the large angular scale correlations in the polarization of the cosmic microwave background (CMB), has created the need for high sensitivity measurements of polarization across large fractions of the sky at millimeter wavelengths. These measurements are subjected to instrumental and atmospheric 1/f noise, which has motivated the development of polarization modulators to facilitate the rejection of these large systematic effects.Variable-delay polarization modulators (VPMs) are used in the Cosmology Large Angular Scale Surveyor (CLASS) telescopes as the first element in the optical chain to rapidly modulate the incoming polarization. VPMs consist of a linearly polarizing wire grid in front of a moveable flat mirror; varying the distance between the grid and the mirror produces a changing phase shift between polarization states parallel and perpendicular to the grid which modulates Stokes U (linear polarization at 45°) and Stokes V (circular polarization). The reflective and scalable nature of the VPM enables its placement as the first optical element in a reflecting telescope. This simultaneously allows a lock-in style polarization measurement and the separation of sky polarization from any instrumental polarization farther along in the optical chain.The Q-Band CLASS VPM was the first VPM to begin observing the CMB full time in 2016. I will be presenting its design and characterization as well as demonstrating how modulating polarization significantly rejects atmospheric and instrumental long time scale noise.

  3. Strategic Polarization.

    Science.gov (United States)

    Kalai, Adam; Kalai, Ehud

    2001-08-01

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

  4. Instrumentation development

    International Nuclear Information System (INIS)

    Ubbes, W.F.; Yow, J.L. Jr.

    1988-01-01

    Instrumentation is developed for the Civilian Radioactive Waste Management Program to meet several different (and sometimes conflicting) objectives. This paper addresses instrumentation development for data needs that are related either directly or indirectly to a repository site, but does not touch on instrumentation for work with waste forms or other materials. Consequently, this implies a relatively large scale for the measurements, and an in situ setting for instrument performance. In this context, instruments are needed for site characterization to define phenomena, develop models, and obtain parameter values, and for later design and performance confirmation testing in the constructed repository. The former set of applications is more immediate, and is driven by the needs of program design and performance assessment activities. A host of general technical and nontechnical issues have arisen to challenge instrumentation development. Instruments can be classed into geomechanical, geohydrologic, or other specialty categories, but these issues cut across artificial classifications. These issues are outlined. Despite this imposing list of issues, several case histories are cited to evaluate progress in the area

  5. A GC Instrument Simulator

    Science.gov (United States)

    Armitage, D. Bruce

    1999-02-01

    This simulator was developed to help students beginning the study of gas chromatographic instruments to understand their operation. It is not meant to teach chromatographic theory. The instrument simulator is divided into 5 sections. One is for sample preparation. Another is used to manage carrier gases and choose a detector and column. The third sets the conditions for either isothermal or programmed temperature operation. A fourth section models manual injections, and the fifth is the autosampler. The operator has a choice among 6 columns of differing diameters and packing polarities and a choice of either isothermal or simple one-stage temperature programming. The simulator can be operated in either single-sample mode or as a 10-sample autosampler. The integrator has two modes of operation, a "dumb" mode in which only the retention time, area of the peak, and percentage area are listed and a "smart" mode that also lists the components' identities. The identities are obtained from a list of names and retention times created by the operator. Without this list only the percentages and areas are listed. The percentages are based on the areas obtained from the chromatogram and not on the actual percentages assigned during sample preparation. The data files for the compounds used in the simulator are ASCII files and can be edited easily to add more compounds than the 11 included with the simulator. A maximum of 10 components can be used in any one sample. Sample mixtures can be made on a percent-by-volume basis, but not by mass of sample per volume of solvent. A maximum of 30 compounds can be present in any one file, but the number of files is limited only by the operating system. (I suggest that not more than 20 compounds be used in any one file, as scrolling through large numbers of compounds is annoying to say the least.) File construction and layout are discussed in detail in the User's Manual. Chromatograms are generated by calculating a retention time based on

  6. Polarized secondary radioactive beams

    International Nuclear Information System (INIS)

    Zaika, N.I.

    1992-01-01

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

  7. Heterogeneous Formation of Polar Stratospheric Clouds- Part 1: Nucleation of Nitric Acid Trihydrate (NAT)

    Science.gov (United States)

    Hoyle, C. R.; Engel, I.; Luo, B. P.; Pitts, M. C.; Poole, L. R.; Grooss, J.-U.; Peter, T.

    2013-01-01

    Satellite-based observations during the Arctic winter of 2009/2010 provide firm evidence that, in contrast to the current understanding, the nucleation of nitric acid trihydrate (NAT) in the polar stratosphere does not only occur on preexisting ice particles. In order to explain the NAT clouds observed over the Arctic in mid-December 2009, a heterogeneous nucleation mechanism is required, occurring via immersion freezing on the surface of solid particles, likely of meteoritic origin. For the first time, a detailed microphysical modelling of this NAT formation pathway has been carried out. Heterogeneous NAT formation was calculated along more than sixty thousand trajectories, ending at Cloud Aerosol Lidar with Orthogonal Polarization (CALIOP) observation points. Comparing the optical properties of the modelled NAT with these observations enabled a thorough validation of a newly developed NAT nucleation parameterisation, which has been built into the Zurich Optical and Microphysical box Model (ZOMM). The parameterisation is based on active site theory, is simple to implement in models and provides substantial advantages over previous approaches which involved a constant rate of NAT nucleation in a given volume of air. It is shown that the new method is capable of reproducing observed polar stratospheric clouds (PSCs) very well, despite the varied conditions experienced by air parcels travelling along the different trajectories. In a companion paper, ZOMM is applied to a later period of the winter, when ice PSCs are also present, and it is shown that the observed PSCs are also represented extremely well under these conditions.

  8. Polar crane

    International Nuclear Information System (INIS)

    Makosinski, S.

    1981-01-01

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

  9. Instrumental analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seung Jae; Seo, Seong Gyu

    1995-03-15

    This textbook deals with instrumental analysis, which consists of nine chapters. It has Introduction of analysis chemistry, the process of analysis and types and form of the analysis, Electrochemistry on basic theory, potentiometry and conductometry, electromagnetic radiant rays and optical components on introduction and application, Ultraviolet rays and Visible spectrophotometry, Atomic absorption spectrophotometry on introduction, flame emission spectrometry and plasma emission spectrometry. The others like infrared spectrophotometry, X-rays spectrophotometry and mass spectrometry, chromatography and the other instrumental analysis like radiochemistry.

  10. Instrumental analysis

    International Nuclear Information System (INIS)

    Kim, Seung Jae; Seo, Seong Gyu

    1995-03-01

    This textbook deals with instrumental analysis, which consists of nine chapters. It has Introduction of analysis chemistry, the process of analysis and types and form of the analysis, Electrochemistry on basic theory, potentiometry and conductometry, electromagnetic radiant rays and optical components on introduction and application, Ultraviolet rays and Visible spectrophotometry, Atomic absorption spectrophotometry on introduction, flame emission spectrometry and plasma emission spectrometry. The others like infrared spectrophotometry, X-rays spectrophotometry and mass spectrometry, chromatography and the other instrumental analysis like radiochemistry.

  11. LOFT instrumentation

    International Nuclear Information System (INIS)

    Bixby, W.W.

    1979-01-01

    A description of instrumentation used in the Loss-of-Fluid Test (LOFT) large break Loss-of-Coolant Experiments is presented. Emphasis is placed on hydraulic and thermal measurements in the primary system piping and components, reactor vessel, and pressure suppression system. In addition, instrumentation which is being considered for measurement of phenomena during future small break testing is discussed. (orig.) 891 HP/orig. 892 BRE [de

  12. Constraining Polarized Foregrounds for EoR Experiments. II. Polarization Leakage Simulations in the Avoidance Scheme

    Energy Technology Data Exchange (ETDEWEB)

    Nunhokee, C. D.; Bernardi, G.; Foster, G.; Grobler, T. L. [Department of Physics and Electronics, Rhodes University, P.O. Box 94, Grahamstown, 6140 (South Africa); Kohn, S. A.; Aguirre, J. E.; Martinot, J. Z. E. [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA (United States); Thyagarajan, N. [Arizona State University, School of Earth and Space Exploration, Tempe, AZ 85287 (United States); Dillon, J. S. [Berkeley Center for Cosmological Physics, Berkeley, CA 94720 (United States); Parsons, A. R., E-mail: cnunhokee@gmail.com [Dept. of Astronomy, University of California, Berkeley, CA 94720 (United States)

    2017-10-10

    A critical challenge in the observation of the redshifted 21 cm line is its separation from bright Galactic and extragalactic foregrounds. In particular, the instrumental leakage of polarized foregrounds, which undergo significant Faraday rotation as they propagate through the interstellar medium, may harmfully contaminate the 21 cm power spectrum. We develop a formalism to describe the leakage due to instrumental widefield effects in visibility-based power spectra measured with redundant arrays, extending the delay-spectrum approach presented in Parsons et al. We construct polarized sky models and propagate them through the instrument model to simulate realistic full-sky observations with the Precision Array to Probe the Epoch of Reionization. We find that the leakage due to a population of polarized point sources is expected to be higher than diffuse Galactic polarization at any k mode for a 30 m reference baseline. For the same reference baseline, a foreground-free window at k > 0.3 h Mpc{sup −1} can be defined in terms of leakage from diffuse Galactic polarization even under the most pessimistic assumptions. If measurements of polarized foreground power spectra or a model of polarized foregrounds are given, our method is able to predict the polarization leakage in actual 21 cm observations, potentially enabling its statistical subtraction from the measured 21 cm power spectrum.

  13. Combining MODIS, MISR, CALIOP, OMI, AERONET, and Models to Identify the Spatial and Temporal Distribution, Characterization, and Magnitude of Missing Urban and Wildfire Emissions Sources throughout Asia.

    Science.gov (United States)

    Cohen, J. B.

    2016-12-01

    Due to intense and changing levels of emissions as well as highly non-linear chemical processing, the concentrations of aerosols and thus their impacts are not well known. Urban areas consist of the majority of the emissions of these species and their precursors over large periods of time, while wildfires contribute very large spikes, concentrated in space and over a period of weeks to months. Yet due to urban and economic expansion, as well as clouds amd low intensity burning, the spatial and temporal profiles of these species are changing, with both new sources appearing and old sources decreasing. New work incorporates measurements at different spatial andboptical resolutions from MODIS, MISR, and OMI, coupled with new sampling approaches with CALIOP and AERONET to search for, characterize, and spatially and temporally constrain aerosols. An advanced modeling system including aerosol chemistry, physics, optics, and transport, using a multi-modal and both externally mixed and core-shell mixing is used to quantify the magnitudes of these missing sources. Comparisons between the model and additional dozens of ground stations show extreme improvement when these new sources are included. This new approach is shown to identify new source regions of emissions, many of which were previously non-urbanized or were not found to contain any fire hotspots. In addition, the use of new models run under conditions including both missing local sources from regions such as the expanded urban areas in Southeast and East Asia and advanced chemical and aerosol routines, allow for a comprehensive analysis to be performed. The impacts of insitu chemistry, horizontal, and vertical transport of species, both on the Regional and Continental scale are also included. It is shown that for proper identification, especially on intra-annual and inter-annual variations, this approach is a large improvement throughout Asia, ranging from India, to Indonesia, to China and Japan. Results specific

  14. Inter-comparison between HERMESv2.0 and TNO-MACC-II emission data using the CALIOPE air quality system (Spain)

    Science.gov (United States)

    Guevara, Marc; Pay, María Teresa; Martínez, Francesc; Soret, Albert; Denier van der Gon, Hugo; Baldasano, José M.

    2014-12-01

    This work examines and compares the performance of two emission datasets on modelling air quality concentrations for Spain: (i) the High-Elective Resolution Modelling Emissions System (HERMESv2.0) and (ii) the TNO-MACC-II emission inventory. For this purpose, the air quality system CALIOPE-AQFS (WRF-ARW/CMAQ/BSC-DREAM8b) was run over Spain for February and June 2009 using the two emission datasets (4 km × 4 km and 1 h). Nitrogen dioxide (NO2), sulphur dioxide (SO2), Ozone (O3) and particular matter (PM10) modelled concentrations were compared with measurements at different type of air quality stations (i.e. rural background, urban, suburban industrial). A preliminary emission comparison showed significant discrepancies between the two datasets, highlighting an overestimation of industrial emissions in urban areas when using TNO-MACC-II. However, simulations showed similar performances of both emission datasets in terms of air quality. Modelled NO2 concentrations were similar between both datasets at the background stations, although TNO-MACC-II presented lower underestimations due to differences in industrial, other mobile sources and residential emissions. At Madrid urban stations NO2 was significantly underestimated in both cases despite the fact that HERMESv2.0 estimates traffic emissions using a more local information and detailed methodology. This NO2 underestimation problem was not found in Barcelona due to the influence of international shipping emissions located in the coastline. An inadequate characterization of some TNO-MACC-II's point sources led to high SO2 biases at industrial stations, especially in northwest Spain where large facilities are grouped. In general, surface O3 was overestimated regardless of the emission dataset used, depicting the problematic of CMAQ on overestimating low ozone at night. On the other hand, modelled PM10 concentrations were less underestimated in urban areas when applying HERMESv2.0 due to the inclusion of road dust

  15. Instrumental Capital

    Directory of Open Access Journals (Sweden)

    Gabriel Valerio

    2007-07-01

    Full Text Available During the history of human kind, since our first ancestors, tools have represented a mean to reach objectives which might otherwise seemed impossibles. In the called New Economy, where tangibles assets appear to be losing the role as the core element to produce value versus knowledge, tools have kept aside man in his dairy work. In this article, the author's objective is to describe, in a simple manner, the importance of managing the organization's group of tools or instruments (Instrumental Capital. The characteristic conditions of this New Economy, the way Knowledge Management deals with these new conditions and the sub-processes that provide support to the management of Instrumental Capital are described.

  16. Polarization of stellar, nebular, and galactic radiation

    Energy Technology Data Exchange (ETDEWEB)

    Shulov, O.S.

    1981-01-01

    The history of polarimetric investigations at the Astronomical Observatory of Leningrad State University is reviewed. Instruments, facilities, and methods used are described, and various studies of lasting importance are summarized. Some results are presented for observations and studies of interstellar polarization and of polarization in close binaries, high-luminosity red and ir stars, several nebulae in the Galaxy, galaxies, galactic nuclei, quasars, N galaxies, and BL Lac objects.

  17. Innovative instrumentation

    International Nuclear Information System (INIS)

    Anon.

    1983-01-01

    At this year's particle physics conference at Brighton, a parallel session was given over to instrumentation and detector development. While this work is vital to the health of research and its continued progress, its share of prime international conference time is limited. Instrumentation can be innovative three times — first when a new idea is outlined, secondly when it is shown to be feasible, and finally when it becomes productive in a real experiment, amassing useful data rather than operational experience. Hyams' examples showed that it can take a long time for a new idea to filter through these successive stages, if it ever makes it at all

  18. Innovative instrumentation

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1983-11-15

    At this year's particle physics conference at Brighton, a parallel session was given over to instrumentation and detector development. While this work is vital to the health of research and its continued progress, its share of prime international conference time is limited. Instrumentation can be innovative three times — first when a new idea is outlined, secondly when it is shown to be feasible, and finally when it becomes productive in a real experiment, amassing useful data rather than operational experience. Hyams' examples showed that it can take a long time for a new idea to filter through these successive stages, if it ever makes it at all.

  19. Nuclear polarization and neutrons

    International Nuclear Information System (INIS)

    Glaettli, H.

    1985-01-01

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

  20. Surgical Instrument

    NARCIS (Netherlands)

    Dankelman, J.; Horeman, T.

    2009-01-01

    The present invention relates to a surgical instrument for minimall-invasive surgery, comprising a handle, a shaft and an actuating part, characterised by a gastight cover surrounding the shaft, wherein the cover is provided with a coupler that has a feed- through opening with a loskable seal,

  1. Weather Instruments.

    Science.gov (United States)

    Brantley, L. Reed, Sr.; Demanche, Edna L.; Klemm, E. Barbara; Kyselka, Will; Phillips, Edwin A.; Pottenger, Francis M.; Yamamoto, Karen N.; Young, Donald B.

    This booklet presents some activities to measure various weather phenomena. Directions for constructing a weather station are included. Instruments including rain gauges, thermometers, wind vanes, wind speed devices, humidity devices, barometers, atmospheric observations, a dustfall jar, sticky-tape can, detection of gases in the air, and pH of…

  2. SUSANS With Polarized Neutrons.

    Science.gov (United States)

    Wagh, Apoorva G; Rakhecha, Veer Chand; Strobl, Makus; Treimer, Wolfgang

    2005-01-01

    Super Ultra-Small Angle Neutron Scattering (SUSANS) studies over wave vector transfers of 10(-4) nm(-1) to 10(-3) nm(-1) afford information on micrometer-size agglomerates in samples. Using a right-angled magnetic air prism, we have achieved a separation of ≈10 arcsec between ≈2 arcsec wide up- and down-spin peaks of 0.54 nm neutrons. The SUSANS instrument has thus been equipped with the polarized neutron option. The samples are placed in a uniform vertical field of 8.8 × 10(4) A/m (1.1 kOe). Several magnetic alloy ribbon samples broaden the up-spin neutron peak significantly over the ±1.3 × 10(-3) nm(-1) range, while leaving the down-spin peak essentially unaltered. Fourier transforms of these SUSANS spectra corrected for the instrument resolution, yield micrometer-range pair distribution functions for up- and down-spin neutrons as well as the nuclear and magnetic scattering length density distributions in the samples.

  3. Neutron polarization in polarized 3He targets

    International Nuclear Information System (INIS)

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

    1990-01-01

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

  4. Analysis of polar organic contaminants in surface water of the northern Adriatic Sea by solid-phase extraction followed by ultrahigh-pressure liquid chromatography-QTRAP® MS using a hybrid triple-quadrupole linear ion trap instrument.

    Science.gov (United States)

    Loos, Robert; Tavazzi, Simona; Paracchini, Bruno; Canuti, Elisabetta; Weissteiner, Christof

    2013-07-01

    Water-soluble polar organic contaminants are discharged by rivers, cities, and ships into the oceans. Little is known on the fate, pollution effects, and thresholds of toxic chemical mixtures in the marine environment. A new trace analytical method was developed for the multi-compound analysis of polar organic chemical contaminants in marine waters. The method is based on automated solid-phase extraction (SPE) of one-liter water samples followed by ultrahigh-pressure liquid chromatography triple-quadrupole linear ion-trap mass spectrometry (UHPLC-QTRAP(®) MS). Marine water samples from the open Adriatic Sea taken 16 km offshore from Venice (Italy) were analyzed. Method limits of quantification (LOQs) in the low picogram per liter (pg/l) concentration range were achieved. Among the 67 target chemicals analyzed, 45 substances could be detected above the LOQ. The chemicals detected at the highest concentrations were caffeine (up to 367 ng/l), nitrophenol (36 ng/l), 2,4-dinitrophenol (34 ng/l), 5-methyl-1H-benzotriazole (18.5 ng/l), sucralose (11 ng/l), 1H-benzotriazole (9.2 ng/l), terbuthylazine (9 ng/l), alachlor (7.7 ng/l), atrazine-desisopropyl (6.6 ng/l), diethyltoluamide (DEET) (5.0 ng/l), terbuthylazine-desethyl (4.3 ng/l), metolachlor (2.8 ng/l), perfluorooctanoic acid (PFOA) (2.5 ng/l), perfluoropentanoic acid (PFPeA) (2.3 ng/l), linuron (2.3 ng/l), perfluorohexanoic acid (PFHxA) (2.2 ng/l), diuron (2.0 ng/l), perfluorohexane sulfonate (PFHxS) (1.6 ng/l), simazine (1.6 ng/l), atrazine (1.5 ng/l), and perfluorooctane sulfonate (PFOS) (1.3 ng/l). Higher concentrations were detected during summer due to increased levels of tourist activity during this period.

  5. Nuclear instrumentation

    International Nuclear Information System (INIS)

    Weill, Jacky; Fabre, Rene.

    1981-01-01

    This article sums up the Research and Development effort at present being carried out in the five following fields of applications: Health physics and Radioprospection, Control of nuclear reactors, Plant control (preparation and reprocessing of the fuel, testing of nuclear substances, etc.), Research laboratory instrumentation, Detectors. It also sets the place of French industrial activities by means of an estimate of the French market, production and flow of trading with other countries [fr

  6. Divided Instruments

    Science.gov (United States)

    Chapman, A.; Murdin, P.

    2000-11-01

    Although the division of the zodiac into 360° probably derives from Egypt or Assyria around 2000 BC, there is no surviving evidence of Mesopotamian cultures embodying this division into a mathematical instrument. Almost certainly, however, it was from Babylonia that the Greek geometers learned of the 360° circle, and by c. 80 BC they had incorporated it into that remarkably elaborate device gener...

  7. Instrumentation development

    International Nuclear Information System (INIS)

    Anon.

    1976-01-01

    Areas being investigated for instrumentation improvement during low-level pollution monitoring include laser opto-acoustic spectroscopy, x-ray fluorescence spectroscopy, optical fluorescence spectroscopy, liquid crystal gas detectors, advanced forms of atomic absorption spectroscopy, electro-analytical chemistry, and mass spectroscopy. Emphasis is also directed toward development of physical methods, as opposed to conventional chemical analysis techniques for monitoring these trace amounts of pollution related to energy development and utilization

  8. Instrumentation maintenance

    International Nuclear Information System (INIS)

    Mack, D.A.

    1976-09-01

    It is essential to any research activity that accurate and efficient measurements be made for the experimental parameters under consideration for each individual experiment or test. Satisfactory measurements in turn depend upon having the necessary instruments and the capability of ensuring that they are performing within their intended specifications. This latter requirement can only be achieved by providing an adequate maintenance facility, staffed with personnel competent to understand the problems associated with instrument adjustment and repair. The Instrument Repair Shop at the Lawrence Berkeley Laboratory is designed to achieve this end. The organization, staffing and operation of this system is discussed. Maintenance policy should be based on studies of (1) preventive vs. catastrophic maintenance, (2) records indicating when equipment should be replaced rather than repaired and (3) priorities established to indicate the order in which equipment should be repaired. Upon establishing a workable maintenance policy, the staff should be instructed so that they may provide appropriate scheduled preventive maintenance, calibration and corrective procedures, and emergency repairs. The education, training and experience of the maintenance staff is discussed along with the organization for an efficient operation. The layout of the various repair shops is described in the light of laboratory space and financial constraints

  9. Polarized electron sources

    International Nuclear Information System (INIS)

    Prepost, R.

    1994-01-01

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

  10. Polarized electron sources

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-12-01

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

  11. Polarized neutron spectrometer

    International Nuclear Information System (INIS)

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

    2000-01-01

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

  12. Wavelength dependence of interstellar polarization

    International Nuclear Information System (INIS)

    Mavko, G.E.

    1974-01-01

    The wavelength dependence of interstellar polarization was measured for twelve stars in three regions of the Milky Way. A 120A bandpass was used to measure the polarization at a maximum of sixteen wavelengths evenly spaced between 2.78μ -1 (3600A) and 1.28μ -1 (7800A). For such a wide wavelength range, the wavelength resolution is superior to that of any previously reported polarization measurements. The new scanning polarimeter built by W. A. Hiltner of the University of Michigan was used for the observations. Very broad structure was found in the wavelength dependence of the polarization. Extensive investigations were carried out to show that the structure was not caused by instrumental effects. The broad structure observed is shown to be in agreement with concurrent extinction measurements for the same stars. Also, the observed structure is of the type predicted when a homogeneous silicate grain model is fitted to the observed extinction. The results are in agreement with the hypothesis that the very broad band structure seen in the extinction is produced by the grains. (Diss. Abstr. Int., B)

  13. Suomi National Polar-Orbiting Partnership Visible Infrared Imaging Radiometer Suite Polarization Sensitivity Analysis

    Science.gov (United States)

    Sun, Junqiang; Xiong, Xiaoxiong; Waluschka, Eugene; Wang, Menghua

    2016-01-01

    The Visible Infrared Imaging Radiometer Suite (VIIRS) is one of five instruments onboard the Suomi National Polar-Orbiting Partnership (SNPP) satellite that launched from Vandenberg Air Force Base, California, on October 28, 2011. It is a whiskbroom radiometer that provides +/-56.28deg scans of the Earth view. It has 22 bands, among which 14 are reflective solar bands (RSBs). The RSBs cover a wavelength range from 410 to 2250 nm. The RSBs of a remote sensor are usually sensitive to the polarization of incident light. For VIIRS, it is specified that the polarization factor should be smaller than 3% for 410 and 862 nm bands and 2.5% for other RSBs for the scan angle within +/-45deg. Several polarization sensitivity tests were performed prelaunch for SNPP VIIRS. The first few tests either had large uncertainty or were less reliable, while the last one was believed to provide the more accurate information about the polarization property of the instrument. In this paper, the measured data in the last polarization sensitivity test are analyzed, and the polarization factors and phase angles are derived from the measurements for all the RSBs. The derived polarization factors and phase angles are band, detector, and scan angle dependent. For near-infrared bands, they also depend on the half-angle mirror side. Nevertheless, the derived polarization factors are all within the specification, although the strong detector dependence of the polarization parameters was not expected. Compared to the Moderate Resolution Imaging Spectroradiometer on both Aqua and Terra satellites, the polarization effect on VIIRS RSB is much smaller.

  14. Hydrogen Distribution in the Lunar Polar Regions

    Science.gov (United States)

    Sanin, A. B.; Mitrofanov, I. G.; Litvak, M. L.; Bakhtin, B. N.; Bodnarik, J. G.; Boynton, W. V.; Chin, G.; Evans, L. G.; Harshmann, K.; Fedosov, F.; hide

    2016-01-01

    We present a method of conversion of the lunar neutron counting rate measured by the Lunar Reconnaissance Orbiter (LRO) Lunar Exploration Neutron Detector (LEND) instrument collimated neutron detectors, to water equivalent hydrogen (WEH) in the top approximately 1 m layer of lunar regolith. Polar maps of the Moon’s inferred hydrogen abundance are presented and discussed.

  15. Polarized neutrons for Australian scientific research

    International Nuclear Information System (INIS)

    Kennedy, Shane J.

    2005-01-01

    Polarized neutron scattering has been a feature at ANSTO's HIFAR research reactor since the first polarization analysis (PA) spectrometer Longpol began operation over 30 years ago. Since that time, we have improved performance of Longpol and added new capabilities in several reincarnations of the instrument. Most of the polarized neutron experiments have been in the fields of magnetism and superconductivity, and most of that research has involved PA. Now as we plan our next generation neutron beam facility, at the Replacement Research Reactor (RRR), we intend to continue the tradition of PA but with a far broader scope in mind. Our new capabilities will combine PA and energy analysis with both cold and thermal neutron source spectra. We will also provide capabilities for research with polarized neutrons in small-angle neutron scattering and in neutron reflectometry. The discussion includes a brief historical account of the technical developments with a summary of past and present applications of polarized neutrons at HIFAR, and an outline of the polarized neutron capabilities that will be included in the first suite of instruments, which will begin operation at the new reactor in 2006

  16. Polarized targets and beams

    International Nuclear Information System (INIS)

    Meyer, W.

    1985-01-01

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

  17. The QUIET Instrument

    Energy Technology Data Exchange (ETDEWEB)

    Bischoff, C.; et al.

    2012-07-01

    The Q/U Imaging ExperimenT (QUIET) is designed to measure polarization in the Cosmic Microwave Background, targeting the imprint of inflationary gravitational waves at large angular scales ({approx}1{sup o}). Between 2008 October and 2010 December, two independent receiver arrays were deployed sequentially on a 1.4m side-fed Dragonian telescope. The polarimeters which form the focal planes use a highly compact design based on High Electron Mobility Transistors (HEMTs) that provides simultaneous measurements of the Stokes parameters Q, U, and I in a single module. The 17-element Q-band polarimeter array, with a central frequency of 43.1 GHz, has the best sensitivity (69 {mu}Ks{sup 1/2}) and the lowest instrumental systematic errors ever achieved in this band, contributing to the tensor-to-scalar ratio at r < 0:1. The 84-element W-band polarimeter array has a sensitivity of 87 {mu}Ks{sup 1/2} at a central frequency of 94.5 GHz. It has the lowest systematic errors to date, contributing at r < 0:01. The two arrays together cover multipoles in the range {ell} {approx} 25 -- 975. These are the largest HEMT-based arrays deployed to date. This article describes the design, calibration, performance of, and sources of systematic error for the instrument.

  18. Scattering with polarized neutrons

    International Nuclear Information System (INIS)

    Schweizer, J.

    2007-01-01

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

  19. Polarized Light Corridor Demonstrations.

    Science.gov (United States)

    Davies, G. R.

    1990-01-01

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

  20. Developing Instrumentation for Ground and Balloon-Borne Observing Platforms

    Data.gov (United States)

    National Aeronautics and Space Administration — In my research I will focus on developing hardware and software technology for two instruments searching for polarization in the Cosmic Microwave Background (CMB)....

  1. Techniques in polarization physics

    International Nuclear Information System (INIS)

    Clausnitzer, G.

    1974-01-01

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

  2. Polarized Moessbauer transitions

    International Nuclear Information System (INIS)

    Barb, D.

    1975-01-01

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

  3. Geographical Income Polarization

    DEFF Research Database (Denmark)

    Azhar, Hussain; Jonassen, Anders Bruun

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

  4. Calculation of polarization effects

    International Nuclear Information System (INIS)

    Chao, A.W.

    1983-09-01

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

  5. Seismic instrumentation

    International Nuclear Information System (INIS)

    1984-06-01

    RFS or Regles Fondamentales de Surete (Basic Safety Rules) applicable to certain types of nuclear facilities lay down requirements with which compliance, for the type of facilities and within the scope of application covered by the RFS, is considered to be equivalent to compliance with technical French regulatory practice. The object of the RFS is to take advantage of standardization in the field of safety, while allowing for technical progress in that field. They are designed to enable the operating utility and contractors to know the rules pertaining to various subjects which are considered to be acceptable by the Service Central de Surete des Installations Nucleaires, or the SCSIN (Central Department for the Safety of Nuclear Facilities). These RFS should make safety analysis easier and lead to better understanding between experts and individuals concerned with the problems of nuclear safety. The SCSIN reserves the right to modify, when considered necessary, any RFS and specify, if need be, the terms under which a modification is deemed retroactive. The aim of this RFS is to define the type, location and operating conditions for seismic instrumentation needed to determine promptly the seismic response of nuclear power plants features important to safety to permit comparison of such response with that used as the design basis

  6. Meteorological instrumentation

    International Nuclear Information System (INIS)

    1982-06-01

    RFS or ''Regles Fondamentales de Surete'' (Basic Safety Rules) applicable to certain types of nuclear facilities lay down requirements with which compliance, for the type of facilities and within the scope of application covered by the RFS, is considered to be equivalent to compliance with technical French regulatory practice. The object of the RFS is to take advantage of standardization in the field of safety , while allowing for technical progress in that field. They are designed to enable the operating utility and contractors to know the rules pertaining to various subjects which are considered to be acceptable by the ''Service Central de Surete des Installations Nucleaires'' or the SCSIN (Central Department for the Safety of Nuclear Facilities). These RFS should make safety analysis easier and lead to better understanding between experts and individuals concerned with the problems of nuclear safety. The SCSIN reserves the right to modify, when considered necessary any RFS and specify, if need be, the terms under which a modification is deemed retroactive. The purpose of this RFS is to specify the meteorological instrumentation required at the site of each nuclear power plant equipped with at least one pressurized water reactor

  7. Luminescence the instrumental key to the future of nanotechnology

    CERN Document Server

    Gilmore, Adam M

    2013-01-01

    PrefaceImportant Spectral and Polarized Properties of Semiconducting SWNT Photoluminescence Shigeo Maruyama and Yuhei MiyauchiImportant Spectral FeaturesPhonon Sideband in AbsorptionVarious Sidebands in EmissionCross-Polarized AbsorptionTransverse Quasi-Dark ExcitonsAdvanced Aspects of Photoluminescence Instrumentation for Carbon Nanotubes Said Kazaoui, Y. Futami, Konstantin Iakoubovskii, and Nobutsugu MinamiIntroductionCNT Thin-Film Fabrication MethodsNIR-PL-Mapping InstrumentsOutlookDevelopments in Catalytic Me

  8. Polarization properties of real aluminum mirrors; I. Influence of the aluminum oxide layer

    NARCIS (Netherlands)

    van Harten, G.; Snik, F.; Keller, C.U.

    2009-01-01

    In polarimetry, it is important to characterize the polarization properties of the instrument itself to disentangle real astrophysical signals from instrumental effects. This article deals with the accurate measurement and modeling of the polarization properties of real aluminum mirrors, as used in

  9. Acceleration of polarized particles

    International Nuclear Information System (INIS)

    Buon, J.

    1992-05-01

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

  10. Lunar ranging instrument for Chandrayaan-1

    Indian Academy of Sciences (India)

    ... Committee on Scientific Values · Project Lifescape · Scientific Data of Public Interest ... Lunar Laser Ranging Instrument (LLRI)proposed for the first Indian lunar ... field by precisely measuring the altitude from a polar orbit around the Moon. ... Laboratory for Electro-Optics Systems, Indian Space Research Organization ...

  11. Radiological instrument

    International Nuclear Information System (INIS)

    Kronenberg, S.; McLaughlin, W.L.; Seibentritt, C.R. Jr.

    1986-01-01

    An instrument is described for measuring radiation, particularly nuclear radiation, comprising: a radiation sensitive structure pivoted toward one end and including a pair of elongated solid members contiguously joined together along their length dimensions and having a common planar interface therebetween. One of the pairs of members is comprised of radiochromic material whose index of refraction changes due to anomolous dispersion as a result of being exposed to nuclear radiation. The pair of members further has mutually different indices of refraction with the member having the larger index of refraction further being transparent for the passage of light and of energy therethrough; means located toward the other end of the structure for varying the angle of longitudinal elevation of the pair of members; means for generating and projecting a beam of light into one end of the member having the larger index of refraction. The beam of light is projected toward the planar interface where it is reflected out of the other end of the same member as a first output beam; means projecting a portion of the beam of light into one end of the member having the larger index of refraction where it traverses therethrough without reflection and out of the other end of the same member as a second output beam; and means adjacent the structure for receiving the first and second output beams, whereby a calibrated change in the angle of elevation of the structure between positions of equal intensity of the first and second output beams prior to and following exposure provides a measure of the radiation sensed due to a change of refraction of the radiochromic material

  12. Polarization effects. Volume 2

    Energy Technology Data Exchange (ETDEWEB)

    Courant, E.

    1981-01-01

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

  13. The Physics of Polarization

    Science.gov (United States)

    Landi Degl'Innocenti, Egidio

    2015-10-01

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

  14. Cosmic microwave background polarization results from QUIET

    International Nuclear Information System (INIS)

    Buder, I.

    2014-01-01

    Despite the success of precision cosmology, cosmologists cannot fully explain the initial conditions of the Universe. Inflation, an exponential expansion in the first ∼ 10 -36 s, is a promising potential explanation. A generic prediction of inflation is odd-parity (B-mode) polarization in the cosmic microwave background (CMB). Q/U Imaging Experiment (QUIET) aimed at limiting or detecting this polarization. We built a pseudo-correlation microwave polarimeter as an array of mass-produced modules in the focal plane of a 1.4 m telescope. We used rotation around the absorbing ground screen, a new time-stream double-demodulation technique, and optimized optics in the design to reduce instrumental polarization. We observed with this instrument at the Atacama Plateau in Chile between October 2008 and December 2010. This paper describes the analysis and results of these observations from one of 2 parallel pipelines. We developed noise modeling, filtering and data selection following a blind-analysis strategy. Central to this strategy was a suite of null test, each motivated by a possible instrumental problem or systematic effect. We evaluated the systematic errors in the blind stage of the analysis before the result was known. We calculated the CMB power spectra using a pseudo-C l cross-correlation technique that suppressed contamination and made the result insensitive to noise bias. We measured the first 3 peaks of the E-mode spectrum at high significance and limited B-mode polarization. We measured the CMB polarization power at 25 ≤ l ≤ 975. We found no statistically significant deviation from ΛCDM model, and our results are consistent with zero BB and EB power. Systematic errors were well below our B-mode polarization limits. This systematic-error reduction was a strong demonstration of technology for application in more sensitive, next generation CMB experiments. (author)

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

    International Nuclear Information System (INIS)

    Itoh, Shinichi

    2004-07-01

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

  16. IASI instrument: technical description and measured performances

    Science.gov (United States)

    Hébert, Ph.; Blumstein, D.; Buil, C.; Carlier, T.; Chalon, G.; Astruc, P.; Clauss, A.; Siméoni, D.; Tournier, B.

    2017-11-01

    IASI is an infrared atmospheric sounder. It will provide meteorologist and scientific community with atmospheric spectra. The IASI system includes 3 instruments that will be mounted on the Metop satellite series, a data processing software integrated in the EPS (EUMETSAT Polar System) ground segment and a technical expertise centre implemented in CNES Toulouse. The instrument is composed of a Fourier transform spectrometer and an associated infrared imager. The optical configuration is based on a Michelson interferometer and the interferograms are processed by an on-board digital processing subsystem, which performs the inverse Fourier transforms and the radiometric calibration. The infrared imager co-registers the IASI soundings with AVHRR imager (AVHRR is another instrument on the Metop satellite). The presentation will focus on the architectures of the instrument, the description of the implemented technologies and the measured performance of the first flight model. CNES is leading the IASI program in association with EUMETSAT. The instrument Prime is ALCATEL SPACE.

  17. Multiphoton polarization Bremsstrahlung effect

    International Nuclear Information System (INIS)

    Golovinskij, P.A.

    2001-01-01

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

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

    Science.gov (United States)

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

    2012-08-01

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

  19. Polarization of Be stars

    International Nuclear Information System (INIS)

    Johns, M.W.

    1975-01-01

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

  20. Polarization at SLC

    International Nuclear Information System (INIS)

    Swartz, M.L.

    1988-07-01

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

  1. The new polarized neutron reflectometer in Juelich

    International Nuclear Information System (INIS)

    Ruecker, U.; Alefeld, B.; Bergs, W.; Kentzinger, E.; Brueckel, T.

    1999-01-01

    On the basis of the HADAS spectrometer in the guide hall of the Juelich research reactor FRJ-2 a polarized neutron reflectometer is build with a 2D-position sensitive detector system. The new spectrometer is optimized for reflectivity and diffuse magnetic scattering measurements with small incident angles on thin magnetic films with thicknesses in the nm range. The polarization analyzer covers the whole detector area, so that a range of 2.5 deg in the scattering angle can be measured simultaneously. The analyzer consists of a stack of supermirrors tilted against the scattering plane. In this reflection geometry, the momentum transfer resolution of the instrument is not reduced, but the sample height is limited to 17 mm. For the monochromator, polarizer and collimation different setups have been compared on the basis of Monte-Carlo calculations: a focusing elliptical supermirror monochromator, a cylindrical mirror, a focusing pyrolytic graphite double monochromator and a double monochromator with bent perfect Si crystals. (author)

  2. The Primordial Inflation Polarization Explorer (PIPER)

    Science.gov (United States)

    Lazear, Justin Scott; Ade, Peter A.; Benford, Dominic J.; Bennett, Charles L.; Chuss, David T.; Dotson, Jessie L.; Eimer, Joseph R.; Fixsen, Dale J.; Halpern, Mark; Hinderks, James; hide

    2014-01-01

    The Primordial Inflation Polarization ExploreR (Piper) is a balloon-borne cosmic microwave background (CMB) polarimeter designed to search for evidence of inflation by measuring the large-angular scale CMB polarization signal. Bicep2 recently reported a detection of B-mode power corresponding to the tensor-to-scalar ratio r = 0.2 on approximately 2 degree scales. If the Bicep2 signal is caused by inflationary gravitational waves (IGWs), then there should be a corresponding increase in B-mode power on angular scales larger than 18 degrees. Piper is currently the only suborbital instrument capable of fully testing and extending the Bicep2 results by measuring the B-mode power spectrum on angular scales theta ? = approximately 0.6 deg to 90 deg, covering both the reionization bump and recombination peak, with sensitivity to measure the tensor-to-scalar ratio down to r = 0.007, and four frequency bands to distinguish foregrounds. Piper will accomplish this by mapping 85% of the sky in four frequency bands (200, 270, 350, 600 GHz) over a series of 8 conventional balloon flights from the northern and southern hemispheres. The instrument has background-limited sensitivity provided by fully cryogenic (1.5 K) optics focusing the sky signal onto four 32×40-pixel arrays of time-domain multiplexed Transition-Edge Sensor (TES) bolometers held at 140 milli-Kelvin. Polarization sensitivity and systematic control are provided by front-end Variabledelay Polarization Modulators (VPMs), which rapidly modulate only the polarized sky signal at 3 Hz and allow Piper to instantaneously measure the full Stokes vector (I,Q,U,0V) for each pointing. We describe the Piper instrument and progress towards its first flight.

  3. Bicep2. III. INSTRUMENTAL SYSTEMATICS

    International Nuclear Information System (INIS)

    Ade, P. A. R.; Aikin, R. W.; Bock, J. J.; Brevik, J. A.; Filippini, J. P.; Golwala, S. R.; Hildebrandt, S. R.; Barkats, D.; Benton, S. J.; Bischoff, C. A.; Buder, I.; Karkare, K. S.; Bullock, E.; Dowell, C. D.; Duband, L.; Fliescher, S.; Halpern, M.; Hasselfield, M.; Hilton, G. C.; Irwin, K. D.

    2015-01-01

    In a companion paper, we have reported a >5σ detection of degree scale B-mode polarization at 150 GHz by the Bicep2 experiment. Here we provide a detailed study of potential instrumental systematic contamination to that measurement. We focus extensively on spurious polarization that can potentially arise from beam imperfections. We present a heuristic classification of beam imperfections according to their symmetries and uniformities, and discuss how resulting contamination adds or cancels in maps that combine observations made at multiple orientations of the telescope about its boresight axis. We introduce a technique, which we call “deprojection,” for filtering the leading order beam-induced contamination from time-ordered data, and show that it reduces power in Bicep2's actual and null-test BB spectra consistent with predictions using high signal-to-noise beam shape measurements. We detail the simulation pipeline that we use to directly simulate instrumental systematics and the calibration data used as input to that pipeline. Finally, we present the constraints on BB contamination from individual sources of potential systematics. We find that systematics contribute BB power that is a factor of ∼10× below Bicep2's three-year statistical uncertainty, and negligible compared to the observed BB signal. The contribution to the best-fit tensor/scalar ratio is at a level equivalent to r = (3–6) × 10 −3

  4. Bicep2. III. INSTRUMENTAL SYSTEMATICS

    Energy Technology Data Exchange (ETDEWEB)

    Ade, P. A. R. [School of Physics and Astronomy, Cardiff University, Cardiff, CF24 3AA (United Kingdom); Aikin, R. W.; Bock, J. J.; Brevik, J. A.; Filippini, J. P.; Golwala, S. R.; Hildebrandt, S. R. [Department of Physics, California Institute of Technology, Pasadena, CA 91125 (United States); Barkats, D. [Joint ALMA Observatory, ESO, Santiago (Chile); Benton, S. J. [Department of Physics, University of Toronto, Toronto, ON (Canada); Bischoff, C. A.; Buder, I.; Karkare, K. S. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street MS 42, Cambridge, MA 02138 (United States); Bullock, E. [Minnesota Institute for Astrophysics, University of Minnesota, Minneapolis, MN 55455 (United States); Dowell, C. D. [Jet Propulsion Laboratory, Pasadena, CA 91109 (United States); Duband, L. [SBT, Commissariat à l’Energie Atomique, Grenoble (France); Fliescher, S. [Department of Physics, University of Minnesota, Minneapolis, MN 55455 (United States); Halpern, M.; Hasselfield, M. [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC (Canada); Hilton, G. C.; Irwin, K. D., E-mail: csheehy@uchicago.edu [National Institute of Standards and Technology, Boulder, CO 80305 (United States); Collaboration: Bicep2 Collaboration; and others

    2015-12-01

    In a companion paper, we have reported a >5σ detection of degree scale B-mode polarization at 150 GHz by the Bicep2 experiment. Here we provide a detailed study of potential instrumental systematic contamination to that measurement. We focus extensively on spurious polarization that can potentially arise from beam imperfections. We present a heuristic classification of beam imperfections according to their symmetries and uniformities, and discuss how resulting contamination adds or cancels in maps that combine observations made at multiple orientations of the telescope about its boresight axis. We introduce a technique, which we call “deprojection,” for filtering the leading order beam-induced contamination from time-ordered data, and show that it reduces power in Bicep2's actual and null-test BB spectra consistent with predictions using high signal-to-noise beam shape measurements. We detail the simulation pipeline that we use to directly simulate instrumental systematics and the calibration data used as input to that pipeline. Finally, we present the constraints on BB contamination from individual sources of potential systematics. We find that systematics contribute BB power that is a factor of ∼10× below Bicep2's three-year statistical uncertainty, and negligible compared to the observed BB signal. The contribution to the best-fit tensor/scalar ratio is at a level equivalent to r = (3–6) × 10{sup −3}.

  5. TRANSVERSELY POLARIZED Λ PRODUCTION

    International Nuclear Information System (INIS)

    BORER, D.

    2000-01-01

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

  6. Our Polar Past

    Science.gov (United States)

    Clary, Renee; Wandersee, James

    2009-01-01

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

  7. Marine polar steroids

    International Nuclear Information System (INIS)

    Stonik, Valentin A

    2001-01-01

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

  8. Polarized proton beams

    International Nuclear Information System (INIS)

    Roser, T.

    1995-01-01

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

  9. Polarization Optics in Telecommunications

    CERN Document Server

    Damask, Jay N

    2005-01-01

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

  10. Parallel Polarization State Generation.

    Science.gov (United States)

    She, Alan; Capasso, Federico

    2016-05-17

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

  11. Evaluating musical instruments

    International Nuclear Information System (INIS)

    Campbell, D. Murray

    2014-01-01

    Scientific measurements of sound generation and radiation by musical instruments are surprisingly hard to correlate with the subtle and complex judgments of instrumental quality made by expert musicians

  12. Polar bears at risk

    Energy Technology Data Exchange (ETDEWEB)

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

    2002-05-01

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

  13. Sensitivity of Gamma-Ray Detectors to Polarization

    OpenAIRE

    Yadigaroglu, I. -A.

    1996-01-01

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

  14. Polarized atomic beams for targets

    International Nuclear Information System (INIS)

    Grueebler, W.

    1984-01-01

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

  15. GUIDE FOR POLARIZED NEUTRONS

    Science.gov (United States)

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

    1962-12-01

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

  16. Heidelberg polarized alkali source

    International Nuclear Information System (INIS)

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

    1984-01-01

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

  17. Deriving the polarization behavior of many-layer mirror coatings

    Science.gov (United States)

    White, Amanda J.; Harrington, David M.; Sueoka, Stacey R.

    2018-06-01

    End-to-end models of astronomical instrument performance are becoming commonplace to demonstrate feasibility and guarantee performance at large observatories. Astronomical techniques like adaptive optics and high contrast imaging have made great strides towards making detailed performance predictions, however, for polarimetric techniques, fundamental tools for predicting performance do not exist. One big missing piece is predicting the wavelength and field of view dependence of a many-mirror articulated optical system particularly with complex protected metal coatings. Predicting polarization performance of instruments requires combining metrology of mirror coatings, tools to create mirror coating models, and optical modeling software for polarized beam propagation. The inability to predict instrument induced polarization or to define polarization performance expectations has far reaching implications for up and coming major observatories, such as the Daniel K. Inouye Solar Telescope (DKIST), that aim to take polarization measurements at unprecedented sensitivity and resolution.Here we present a method for modelling the wavelength dependent refractive index of an optic using Berreman calculus - a mathematical formalism that describes how an electromagnetic field propagates through a birefringent medium. From Berreman calculus, we can better predict the Mueller matrix, diattenuation, and retardance of an arbitrary thicknesses of amorphous many-layer coatings as well as stacks of birefringent crystals from laboratory measurements. This will allow for the wavelength dependent refractive index to be accurately determined and the polarization behavior to be derived for a given optic.

  18. IOT Overview: IR Instruments

    Science.gov (United States)

    Mason, E.

    In this instrument review chapter the calibration plans of ESO IR instruments are presented and briefly reviewed focusing, in particular, on the case of ISAAC, which has been the first IR instrument at VLT and whose calibration plan served as prototype for the coming instruments.

  19. The representation of neutron polarization

    International Nuclear Information System (INIS)

    Byrne, J.

    1979-01-01

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

  20. Health physics instrument manual

    International Nuclear Information System (INIS)

    Gupton, E.D.

    1978-08-01

    The purpose of this manual is to provide apprentice health physics surveyors and other operating groups not directly concerned with radiation detection instruments a working knowledge of the radiation detection and measuring instruments in use at the Laboratory. The characteristics and applications of the instruments are given. Portable instruments, stationary instruments, personnel monitoring instruments, sample counters, and miscellaneous instruments are described. Also, information sheets on calibration sources, procedures, and devices are included. Gamma sources, beta sources, alpha sources, neutron sources, special sources, a gamma calibration device for badge dosimeters, and a calibration device for ionization chambers are described

  1. Astronomical Instruments in India

    Science.gov (United States)

    Sarma, Sreeramula Rajeswara

    The earliest astronomical instruments used in India were the gnomon and the water clock. In the early seventh century, Brahmagupta described ten types of instruments, which were adopted by all subsequent writers with minor modifications. Contact with Islamic astronomy in the second millennium AD led to a radical change. Sanskrit texts began to lay emphasis on the importance of observational instruments. Exclusive texts on instruments were composed. Islamic instruments like the astrolabe were adopted and some new types of instruments were developed. Production and use of these traditional instruments continued, along with the cultivation of traditional astronomy, up to the end of the nineteenth century.

  2. A statistical assessment of zero-polarization catalogues

    Science.gov (United States)

    Clarke, D.; Naghizadeh-Khouei, J.; Simmons, J. F. L.; Stewart, B. G.

    1993-03-01

    The statistical behavior associated with polarization measurements is presented. The cumulative distribution function for measurements of unpolarized sources normalized by the measurement error is considered and Kolmogorov tests have been applied to data which might be considered as being representative of assemblies of unpolarized stars. Tinbergen's (1979, 1982) and Piirola's I (1977) catalogs have been examined and reveal shortcomings, the former indicating the presence of uncorrected instrumental polarization in part of the data and both suggesting that the quoted errors are in general slightly underestimated. Citings of these catalogs as providing evidence that middle-type stars in general exhibit weak intrinsic polarizations are shown to be invalid.

  3. Time asymmetry: Polarization and analyzing power in the nuclear reactions

    International Nuclear Information System (INIS)

    Rioux, C.; Roy, R.; Slobodrian, R.J.; Conzett, H.E.

    1983-01-01

    Measurements of the proton polarization in the reactions 7 Li( 3 He, p vector) 9 Be and 9 Be( 3 He, p vector) 11 B and of the analyzing powers of the inverse reactions, initiated by polarized protons at the same c.m. energies, show significant differences which imply the failure of the polarization-analyzing-power theorem and, prima facie, of time-reversal invariance in these reactions. The reaction 2 H( 3 He, p vector) 4 He and its inverse have also been investigated and show some smaller differences. A discussion of the instrumental asymmetries is presented. (orig.)

  4. Polarized neutron spectrometer for inelastic experiments at J-PARC

    Directory of Open Access Journals (Sweden)

    Yokoo Tetsuya

    2015-01-01

    Full Text Available Construction of the newly developed polarization analysis neutron chopper spectrometer (POLANO commenced in the Japan Proton Accelerator Research Complex (J-PARC, Materials and Life Science Experimental Facility (MLF. The POLANO is a direct geometry chopper spectrometer with neutron polarization analysis capability. In the suite of inelastic spectrometers, six instruments are now in operation. POLANO will be the only spectrometer dedicated to polarization analysis experiments. The primary phase of the construction will be completed by 2014 with beam commissioning scheduled for 2015.

  5. Troubleshooting in nuclear instruments

    International Nuclear Information System (INIS)

    1987-06-01

    This report on troubleshooting of nuclear instruments is the product of several scientists and engineers, who are closely associated with nuclear instrumentation and with the IAEA activities in the field. The text covers the following topics: Preamplifiers, amplifiers, scalers, timers, ratemeters, multichannel analyzers, dedicated instruments, tools, instruments, accessories, components, skills, interfaces, power supplies, preventive maintenance, troubleshooting in systems, radiation detectors. The troubleshooting and repair of instruments is illustrated by some real examples

  6. Interferometric polarization control

    International Nuclear Information System (INIS)

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

    2006-01-01

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

  7. Dynamic nuclear spin polarization

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-11-01

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

  8. Polarized proton colliders

    International Nuclear Information System (INIS)

    Roser, T.

    1995-01-01

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

  9. Plasma polarization spectroscopy

    International Nuclear Information System (INIS)

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

    2005-01-01

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

  10. No More Polarization, Please!

    OpenAIRE

    Reinholt, Mia

    2006-01-01

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

  11. Inertial polarization of dielectrics

    OpenAIRE

    Zavodovsky, A. G.

    2011-01-01

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

  12. Beam instrumentation in the AGS Booster

    International Nuclear Information System (INIS)

    Witkover, R.L.

    1991-01-01

    The AGS Booster was designed to accelerate low intensity (2 x 10 10 ) polarized protons, high intensity (1.5x10 13 ) protons and heavy ions through Au +33 . Coping with this wide range of beams, the 3 x 10 -11 Torr vacuum and the radiation environment presented challenges for the beam monitors. Some of the more interesting instrumentation design and performance during the recent Booster proton commissioning will be described

  13. New beam instrumentation in the AGS Booster

    International Nuclear Information System (INIS)

    Witkover, R.L.

    1991-01-01

    The AGS Booster was designed to accelerate beams from 2x10 10 polarized protons to 1.5x10 13 protons and heavy ions through Au +33 . The range of beam parameters and the high vacuum, and radiation environment presented challenges for the beam instrumentation. Some interesting beam monitors in the Booster and transport lines, will be described. Where available, results will be presented. 21 refs., 7 figs

  14. New beam instrumentation in the AGS Booster

    Energy Technology Data Exchange (ETDEWEB)

    Witkover, R.L.

    1991-01-01

    The AGS Booster was designed to accelerate beams from 2{times}10{sup 10} polarized protons to 1.5{times}10{sup 13} protons and heavy ions through Au{sup +33}. The range of beam parameters and the high vacuum, and radiation environment presented challenges for the beam instrumentation. Some interesting beam monitors in the Booster and transport lines, will be described. Where available, results will be presented. 21 refs., 7 figs.

  15. The Polarization of Achernar

    Science.gov (United States)

    McDavid, D.

    2005-11-01

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

  16. Fusion of a polarized projectile with a polarized target

    International Nuclear Information System (INIS)

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

    1995-01-01

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

  17. Development of a polarized neutron beam line at Algerian research reactors using McStas software

    Energy Technology Data Exchange (ETDEWEB)

    Makhloufi, M., E-mail: makhloufi_8m@yahoo.fr [Centre de Recherche Nucléaire de Birine (Algeria); Salah, H. [Centre de Recherche Nucléaire d' Alger (Algeria)

    2017-02-01

    Unpolarized instrumentation has long been studied and designed using McStas simulation tool. But, only recently new models were developed for McStas to simulate polarized neutron scattering instruments. In the present contribution, we used McStas software to design a polarized neutron beam line, taking advantage of the available spectrometers reflectometer and diffractometer in Algeria. Both thermal and cold neutron was considered. The polarization was made by two types of supermirrors polarizers FeSi and CoCu provided by the HZB institute. For sake of performance and comparison, the polarizers were characterized and their characteristics reproduced. The simulated instruments are reported. Flipper and electromagnets for guide field are developed. Further developments including analyzers and upgrading of the existing spectrometers are underway. - Highlights: • Permit to evaluate the feasibility of a polarized neutron scattering instrument prior to its implementation. • Help to understand the origin of instrumental imperfections and offer an optimized set up configuration. • Provide the possibility to use the FeSi and CoCu supermirrors, designed to polarize spin up cold neutron, to polarize thermal neutron.

  18. Development of a polarized neutron beam line at Algerian research reactors using McStas software

    International Nuclear Information System (INIS)

    Makhloufi, M.; Salah, H.

    2017-01-01

    Unpolarized instrumentation has long been studied and designed using McStas simulation tool. But, only recently new models were developed for McStas to simulate polarized neutron scattering instruments. In the present contribution, we used McStas software to design a polarized neutron beam line, taking advantage of the available spectrometers reflectometer and diffractometer in Algeria. Both thermal and cold neutron was considered. The polarization was made by two types of supermirrors polarizers FeSi and CoCu provided by the HZB institute. For sake of performance and comparison, the polarizers were characterized and their characteristics reproduced. The simulated instruments are reported. Flipper and electromagnets for guide field are developed. Further developments including analyzers and upgrading of the existing spectrometers are underway. - Highlights: • Permit to evaluate the feasibility of a polarized neutron scattering instrument prior to its implementation. • Help to understand the origin of instrumental imperfections and offer an optimized set up configuration. • Provide the possibility to use the FeSi and CoCu supermirrors, designed to polarize spin up cold neutron, to polarize thermal neutron.

  19. Performing the Super Instrument

    DEFF Research Database (Denmark)

    Kallionpaa, Maria

    2016-01-01

    can empower performers by producing super instrument works that allow the concert instrument to become an ensemble controlled by a single player. The existing instrumental skills of the performer can be multiplied and the qualities of regular acoustic instruments extended or modified. Such a situation......The genre of contemporary classical music has seen significant innovation and research related to new super, hyper, and hybrid instruments, which opens up a vast palette of expressive potential. An increasing number of composers, performers, instrument designers, engineers, and computer programmers...... have become interested in different ways of “supersizing” acoustic instruments in order to open up previously-unheard instrumental sounds. Super instruments vary a great deal but each has a transformative effect on the identity and performance practice of the performing musician. Furthermore, composers...

  20. Polarized Light Microscopy

    Science.gov (United States)

    Frandsen, Athela F.

    2016-01-01

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

  1. When measured spin polarization is not spin polarization

    International Nuclear Information System (INIS)

    Dowben, P A; Wu Ning; Binek, Christian

    2011-01-01

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

  2. Self-adaptive demodulation for polarization extinction ratio in distributed polarization coupling.

    Science.gov (United States)

    Zhang, Hongxia; Ren, Yaguang; Liu, Tiegen; Jia, Dagong; Zhang, Yimo

    2013-06-20

    A self-adaptive method for distributed polarization extinction ratio (PER) demodulation is demonstrated. It is characterized by dynamic PER threshold coupling intensity (TCI) and nonuniform PER iteration step length (ISL). Based on the preset PER calculation accuracy and original distribution coupling intensity, TCI and ISL can be made self-adaptive to determine contributing coupling points inside the polarizing devices. Distributed PER is calculated by accumulating those coupling points automatically and selectively. Two different kinds of polarization-maintaining fibers are tested, and PERs are obtained after merely 3-5 iterations using the proposed method. Comparison experiments with Thorlabs commercial instrument are also conducted, and results show high consistency. In addition, the optimum preset PER calculation accuracy of 0.05 dB is obtained through many repeated experiments.

  3. The evolution of tensor polarization

    International Nuclear Information System (INIS)

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

    1993-01-01

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

  4. The polarization of fast neutrons

    International Nuclear Information System (INIS)

    Talov, V.V.

    2000-01-01

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

  5. HST observations of the limb polarization of Titan

    Science.gov (United States)

    Bazzon, A.; Schmid, H. M.; Buenzli, E.

    2014-12-01

    the hazy atmosphere of Titan. Planets with hazy atmospheres similar to Titan are particularly good candidates for detection with the polarimetric mode of the upcoming planet finder instrument at the VLT. Therefore, a good knowledge of the polarization properties of Titan is also important for the search and investigation of extra-solar planets.

  6. Polarized particles in storage rings

    International Nuclear Information System (INIS)

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

    1977-01-01

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

  7. Forward instrumentation for ILC detectors

    International Nuclear Information System (INIS)

    Abramowicz, Halina; Abusleme, Angel; Afanaciev, Konstantin

    2010-09-01

    Two special calorimeters are foreseen for the instrumentation of the very forward region of the ILC detector, a luminometer designed to measure the rate of low angle Bhabha scattering events with a precision better than 10 -3 and a low polar angle calorimeter, adjacent to the beam-pipe. The latter will be hit by a large amount of beamstrahlung remnants. The amount and shape of these depositions will allow a fast luminosity estimate and the determination of beam parameters. The sensors of this calorimeter must be radiation hard. Both devices will improve the hermeticity of the detector in the search for new particles. Finely segmented and very compact calorimeters will match the requirements. Due to the high occupancy fast front-end electronics is needed. The design of the calorimeters developed and optimised with Monte Carlo simulations is presented. Sensors and readout electronics ASICs have been designed and prototypes are available. Results on the performance of these major components are summarised. (orig.)

  8. Forward Instrumentation for ILC Detectors

    CERN Document Server

    Abramowicz, Halina; Afanaciev, Konstantin; Aguilar, Jonathan; Ambalathankandy, Prasoon; Bambade, Philip; Bergholz, Matthias; Bozovic-Jelisavcic, Ivanka; Castro, Elena; Chelkov, Georgy; Coca, Cornelia; Daniluk, Witold; Dragone, Angelo; Dumitru, Laurentiu; Elsener, Konrad; Emeliantchik, Igor; Fiutowski, Tomasz; Gostkin, Mikhail; Grah, Christian; Grzelak, Grzegorz; Haller, Gunter; Henschel, Hans; Ignatenko, Alexandr; Idzik, Marek; Ito, Kazutoshi; Jovin, Tatjana; Kielar, Eryk; Kotula, Jerzy; Krumstein, Zinovi; Kulis, Szymon; Lange, Wolfgang; Lohmann, Wolfgang; Levy, Aharon; Moszczynski, Arkadiusz; Nauenberg, Uriel; Novgorodova, Olga; Ohlerich, Marin; Orlandea, Marius; Oleinik, Gleb; Oliwa, Krzysztof; Olshevski, Alexander; Pandurovic, Mila; Pawlik, Bogdan; Przyborowski, Dominik; Sato, Yutaro; Sadeh, Iftach; Sailer, Andre; Schmidt, Ringo; Schumm, Bruce; Schuwalow, Sergey; Smiljanic, Ivan; Swientek, Krzysztof; Takubo, Yosuke; Teodorescu, Eliza; Wierba, Wojciech; Yamamoto, Hitoshi; Zawiejski, Leszek; Zhang, Jinlong

    2010-01-01

    Two special calorimeters are foreseen for the instrumentation of the very forward region of the ILC detector, a luminometer designed to measure the rate of low angle Bhabha scattering events with a precision better than 10-3 and a low polar angle calorimeter, adjacent to the beam-pipe. The latter will be hit by a large amount of beamstrahlung remnants. The amount and shape of these depositions will allow a fast luminosity estimate and the determination of beam parameters. The sensors of this calorimeter must be radiation hard. Both devices will improve the hermeticity of the detector in the search for new particles. Finely segmented and very compact calorimeters will match the requirements. Due to the high occupancy fast front-end electronics is needed. The design of the calorimeters developed and optimised with Monte Carlo simulations is presented. Sensors and readout electronics ASICs have been designed and prototypes are available. Results on the performance of these major components are summarised.

  9. Polarized electrons at Jefferson laboratory

    International Nuclear Information System (INIS)

    Sinclair, C.K.

    1998-01-01

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

  10. Polarized Electrons at Jefferson Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Sinclair, C.K.

    1997-12-31

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

  11. Polarization: A Must for Fusion

    Directory of Open Access Journals (Sweden)

    Guidal M.

    2012-10-01

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

  12. Development of a polarized neutron beam line at Algerian research reactors using McStas software

    Science.gov (United States)

    Makhloufi, M.; Salah, H.

    2017-02-01

    Unpolarized instrumentation has long been studied and designed using McStas simulation tool. But, only recently new models were developed for McStas to simulate polarized neutron scattering instruments. In the present contribution, we used McStas software to design a polarized neutron beam line, taking advantage of the available spectrometers reflectometer and diffractometer in Algeria. Both thermal and cold neutron was considered. The polarization was made by two types of supermirrors polarizers FeSi and CoCu provided by the HZB institute. For sake of performance and comparison, the polarizers were characterized and their characteristics reproduced. The simulated instruments are reported. Flipper and electromagnets for guide field are developed. Further developments including analyzers and upgrading of the existing spectrometers are underway.

  13. Study by polarized muon

    International Nuclear Information System (INIS)

    Yamazaki, Toshimitsu

    1977-01-01

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

  14. Polarized protons at RHIC

    International Nuclear Information System (INIS)

    Tannenbaum, M.J.

    1990-12-01

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

  15. The Bochum Polarized Target

    International Nuclear Information System (INIS)

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

    2001-01-01

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

  16. Temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from USCGC POLAR SEA in the South Pacific Ocean and Southern Oceans from 1994-02-04 to 1994-02-10 (NODC Accession 0116062)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0116062 includes chemical, discrete sample, physical and profile data collected from USCGC POLAR SEA in the South Pacific Ocean and Southern Oceans...

  17. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the USCGC POLAR SEA in the North Greenland Sea from 1992-07-15 to 1992-08-14 (NODC Accession 0115687)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0115687 includes biological, chemical, discrete sample, physical and profile data collected from USCGC POLAR SEA in the North Greenland Sea from...

  18. Partial pressure (or fugacity) of carbon dioxide, dissolved inorganic carbon, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the USCGC POLAR SEA in the North Greenland Sea from 1993-07-18 to 1993-08-20 (NODC Accession 0114447)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0114447 includes biological, chemical, discrete sample, physical and profile data collected from USCGC POLAR SEA in the North Greenland Sea from...

  19. Mechanisms of Cell Polarity-Controlled Epithelial Homeostasis and Immunity in the Intestine

    NARCIS (Netherlands)

    Klunder, Leon J.; Faber, Klaas Nico; Dijkstra, Gerard; van IJzendoorn, Sven C. D.

    Intestinal epithelial cell polarity is instrumental to maintain epithelial homeostasis and balance communications between the gut lumen and bodily tissue, thereby controlling the defense against gastrointestinal pathogens and maintenance of immune tolerance to commensal bacteria. In this review, we

  20. Optical characterization and polarization calibration for rigid endoscopes

    Science.gov (United States)

    Garcia, Missael; Gruev, Viktor

    2017-02-01

    Polarization measurements give orthogonal information to spectral images making them a great tool in the characterization of environmental parameters in nature. Thus, polarization imagery has proven to be remarkably useful in a vast range of biomedical applications. One such application is the early diagnosis of flat cancerous lesions in murine colorectal tumor models, where polarization data complements NIR fluorescence analysis. Advances in nanotechnology have led to compact and precise bio-inspired imaging sensors capable of accurately co-registering multidimensional spectral and polarization information. As more applications emerge for these imagers, the optics used in these instruments get very complex and can potentially compromise the original polarization state of the incident light. Here we present a complete optical and polarization characterization of three rigid endoscopes of size 1.9mm x 10cm (Karl Storz, Germany), 5mm x 30cm, and 10mm x 33cm (Olympus, Germany), used in colonoscopy for the prevention of colitis-associated cancer. Characterization results show that the telescope optics act as retarders and effectively depolarize the linear component. These incorrect readings can cause false-positives or false-negatives leading to an improper diagnosis. In this paper, we offer a polarization calibration scheme for these endoscopes based on Mueller calculus. By modeling the optical properties from training data as real-valued Mueller matrices, we are able to successfully reconstruct the initial polarization state acquired by the imaging system.

  1. Instrument Modeling and Synthesis

    Science.gov (United States)

    Horner, Andrew B.; Beauchamp, James W.

    During the 1970s and 1980s, before synthesizers based on direct sampling of musical sounds became popular, replicating musical instruments using frequency modulation (FM) or wavetable synthesis was one of the “holy grails” of music synthesis. Synthesizers such as the Yamaha DX7 allowed users great flexibility in mixing and matching sounds, but were notoriously difficult to coerce into producing sounds like those of a given instrument. Instrument design wizards practiced the mysteries of FM instrument design.

  2. Nuclear reactor instrumentation

    International Nuclear Information System (INIS)

    Duncombe, E.; McGonigal, G.

    1975-01-01

    A liquid metal cooled nuclear reactor is described which has an equal number of fuel sub-assemblies and sensing instruments. Each instrument senses temperature and rate of coolant flow of a coolant derived from a group of three sub-assemblies so that an abnormal value for one sub-assembly will be indicated on three instruments thereby providing for redundancy of up to two of the three instruments. The abnormal value may be a precurser to unstable boiling of coolant

  3. Polarized source upgrading

    International Nuclear Information System (INIS)

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

    1985-01-01

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

  4. Spin polarized deuterium

    International Nuclear Information System (INIS)

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

    1986-01-01

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

  5. Polarized electron sources

    International Nuclear Information System (INIS)

    Clendenin, J.E.

    1995-05-01

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

  6. Time Domain Induced Polarization

    DEFF Research Database (Denmark)

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

    2012-01-01

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

  7. A lunar polar expedition

    Science.gov (United States)

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

    1992-09-01

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

  8. Aeroacoustics of Musical Instruments

    NARCIS (Netherlands)

    Fabre, B.; Gilbert, J.; Hirschberg, Abraham; Pelorson, X.

    2012-01-01

    We are interested in the quality of sound produced by musical instruments and their playability. In wind instruments, a hydrodynamic source of sound is coupled to an acoustic resonator. Linear acoustics can predict the pitch of an instrument. This can significantly reduce the trial-and-error process

  9. Modelling Polar Self Assembly

    Science.gov (United States)

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

    2001-03-01

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

  10. AGS polarized H- source

    International Nuclear Information System (INIS)

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

    1985-01-01

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

  11. The polar mesosphere

    International Nuclear Information System (INIS)

    Morris, Ray; Murphy, Damian

    2008-01-01

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

  12. Imaging with Polarized Neutrons

    Directory of Open Access Journals (Sweden)

    Nikolay Kardjilov

    2018-01-01

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

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

    Science.gov (United States)

    Kwon, Do-Hoon; Werner, Douglas H

    2008-11-10

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

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

    Science.gov (United States)

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

    2018-01-01

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

  15. Polarized Proton Collisions at RHIC

    CERN Document Server

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

    2005-01-01

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

  16. Investigation of propagation algorithms for ray-tracing simulation of polarized neutrons

    DEFF Research Database (Denmark)

    Bergbäck Knudsen, Erik; Tranum-Rømer, A.; Willendrup, Peter Kjær

    2014-01-01

    Ray-tracing of polarized neutrons faces a challenge when the neutron propagates through an inhomogeneous magnetic field. This affects simulations of novel instruments using encoding of energy or angle into the neutron spin. We here present a new implementation of propagation of polarized neutrons...

  17. Status of safeguards instrumentation

    International Nuclear Information System (INIS)

    Higinbotham, W.A.

    The International Atomic Energy Agency is performing safeguards at some nuclear power reactors, 50 bulk processing facilities, and 170 research facilities. Its verification activities require the use of instruments to measure nuclear materials and of surveillance instruments to maintain continuity of knowledge of the locations of nuclear materials. Instruments that are in use and under development to measure weight, volume, concentration, and isotopic composition of nuclear materials, and the major surveillance instruments, are described in connection with their uses at representative nuclear facilities. The current status of safeguards instrumentation and the needs for future development are discussed

  18. Early modern mathematical instruments.

    Science.gov (United States)

    Bennett, Jim

    2011-12-01

    In considering the appropriate use of the terms "science" and "scientific instrument," tracing the history of "mathematical instruments" in the early modern period is offered as an illuminating alternative to the historian's natural instinct to follow the guiding lights of originality and innovation, even if the trail transgresses contemporary boundaries. The mathematical instrument was a well-defined category, shared across the academic, artisanal, and commercial aspects of instrumentation, and its narrative from the sixteenth to the eighteenth century was largely independent from other classes of device, in a period when a "scientific" instrument was unheard of.

  19. Polarized coincidence electroproduction

    International Nuclear Information System (INIS)

    Heimann, R.L.

    1975-03-01

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

  20. Fluorescence confocal polarizing microscopy

    Indian Academy of Sciences (India)

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

  1. Optical neutron polarizers

    International Nuclear Information System (INIS)

    Hayter, J.B.

    1990-01-01

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

  2. Titan Polar Landscape Evolution

    Science.gov (United States)

    Moore, Jeffrey M.

    2016-01-01

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

  3. The polarized EMC effect

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-02-01

    We calculate both the spin independent and spin dependent nuclear structure functions in an effective quark theory. The nucleon is described as a composite quark-diquark state, and the nucleus is treated in the mean field approximation. We predict a sizable polarized EMC effect, which could be confirmed in future experiments.

  4. Polarizer reflectivity variations

    International Nuclear Information System (INIS)

    Ozarski, R.G.; Prior, J.

    1980-01-01

    On Shiva the beam energy along the chain is monitored using available reflections and/or transmission through beam steering, splitting, and polarizing optics without the intrusion of any additional glass for diagnostics. On the preamp table the diagnostic signal is obtained from the signal transmitted through turning mirrors. At the input of each chain the signal is obtained from the transmission through one of the mirrors used for the chain input alignment sensor (CHIP). At the chain output the transmission through the final turning mirror is used. These diagnostics have proved stable and reliable. However, one of the prime diagnostic locations is at the output of the beta rod. The energy at this location is measured by collecting small reflections from the last polarizer surface of the beta Pockels cell polarizer package. Unfortunately, calibration of this diagnostic has varied randomly, seldom remaining stable for a week or more. The cause of this fluctuation has been investigated for the past year and'it has been discovered that polarizer reflectivity varies with humidity. This report will deal with the possible causes that were investigated, the evidence that humidity is causing the variation, and the associated mechanism

  5. Spin-polarized photoemission

    International Nuclear Information System (INIS)

    Johnson, Peter D.

    1997-01-01

    Spin-polarized photoemission has developed into a versatile tool for the study of surface and thin film magnetism. In this review, we examine the methodology of the technique and its application to a number of different problems, including both valence band and core level studies. After a detailed review of spin-polarization measurement techniques and the related experimental requirements we consider in detail studies of the bulk properties both above and below the Curie temperature. This section also includes a discussion of observations relating to unique metastable phases obtained via epitaxial growth. The application of the technique to the study of surfaces, both clean and adsorbate covered, is reviewed. The report then examines, in detail, studies of the spin-polarized electronic structure of thin films and the related interfacial magnetism. Finally, observations of spin-polarized quantum well states in non-magnetic thin films are discussed with particular reference to their mediation of the oscillatory exchange coupling in related magnetic multilayers. (author)

  6. Polarization of Bremsstrahlung

    International Nuclear Information System (INIS)

    Miller, J.

    1957-01-01

    The numerical results for the polarization of Bremsstrahlung are presented. The multiple scattering of electrons in the target is taken into account. The angular-and photon energy dependences are seen on the curves for an incident 25 MeV electron energy. (Author) [fr

  7. No More Polarization, Please!

    DEFF Research Database (Denmark)

    Hansen, Mia Reinholt

    and the increasing levels of complexities it entails, such polarization is not fruitful in the attempt to explain motivation of organizational members. This paper claims that a more nuanced perspective on motivation, acknowledging the co-existence of intrinsic and extrinsic motivation, the possible interaction...

  8. DESY: HERA polarization

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    The new HERA electron-proton collider at DESY in Hamburg achieved the first luminosity for electron-proton collisions on 19 October last year. Only one month later, on 20 November, HERA passed another important milestone with the observation of transverse electron polarization

  9. Polarized Neutron Scattering

    OpenAIRE

    Roessli, B.; Böni, P.

    2000-01-01

    The technique of polarized neutron scattering is reviewed with emphasis on applications. Many examples of the usefulness of the method in various fields of physics are given like the determination of spin density maps, measurement of complex magnetic structures with spherical neutron polarimetry, inelastic neutron scattering and separation of coherent and incoherent scattering with help of the generalized XYZ method.

  10. DESY: HERA polarization

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1992-03-15

    The new HERA electron-proton collider at DESY in Hamburg achieved the first luminosity for electron-proton collisions on 19 October last year. Only one month later, on 20 November, HERA passed another important milestone with the observation of transverse electron polarization.

  11. Graphics of polar figure

    International Nuclear Information System (INIS)

    Macias B, L.R.

    1991-11-01

    The objective of this work, is that starting from a data file coming from a spectra that has been softened, and of the one that have been generated its coordinates to project it in stereographic form, to create the corresponding polar figure making use of the Cyber computer of the ININ by means of the GRAPHOS package. This work only requires a Beta, Fi and Intensity (I) enter data file. It starts of the existence of a softened spectra of which have been generated already with these data, making use of some language that in this case was FORTRAN for the Cyber computer, a program is generated supported in the Graphos package that allows starting of a reading of the Beta, Fi, I file, to generate the points in a stereographic projection and that it culminates with the graph of the corresponding polar figure. The program will request the pertinent information that is wanted to capture in the polar figure just as: date, name of the enter file, indexes of the polar figure, number of levels, radio of the stereographic projection (cms.), crystalline system to which belongs the sample, name the neuter graph file by create and to add the own general data. (Author)

  12. An Imaging Polar Nephelometer

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This invention relates to measuring the light that is scattered from particulates (aerosols) in a gas or liquid. The sample typically flows into the instrument and...

  13. Polarized nuclear target based on parahydrogen induced polarization

    OpenAIRE

    Budker, D.; Ledbetter, M. P.; Appelt, S.; Bouchard, L. S.; Wojtsekhowski, B.

    2012-01-01

    We discuss a novel concept of a polarized nuclear target for accelerator fixed-target scattering experiments, which is based on parahydrogen induced polarization (PHIP). One may be able to reach a 33% free-proton polarization in the ethane molecule. The potential advantages of such a target include operation at zero magnetic field, fast ($\\sim$100 Hz) polarization reversal, and operation with large intensity of an electron beam.

  14. Polarization measurements of auroral kilometric radiation by Dynamics Explorer-1

    International Nuclear Information System (INIS)

    Shawhan, S.D.; Gurnett, D.A.

    1982-01-01

    The plasma wave instrument (PWI) on the Dynamics Explorer-1 has been used to measure polarization of auroral kilometric radiation (AKR) at frequencies of 50 to 400 kHz in both the northern and the southern nightside auroral regions at altitudes of 1 to 3 R/sub E/ above the AKR source regions. The AKR polarization sense is found to be the same as the right hand polarized auroral hiss found in the frequency range of 0.8 to 6.4 kHz. Consequently, these unambiguous direct polarization measurements of AKR lead to the conclusion that AKR escapes the magnetosphere in the R-X mode. Since DE-1 is close to the source region, it can be inferred that AKR is generated predominately in the R-X mode

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

    Science.gov (United States)

    Produit, Nicolas

    2012-07-01

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

  16. Experiments with Fermilab polarized proton and polarized antiproton beams

    International Nuclear Information System (INIS)

    Yokosawa, A.

    1990-01-01

    We summarize activities concerning the Fermilab polarized beams. They include a brief description of the polarized-beam facility, measurements of beam polarization by polarimeters, asymmetry measurements in the π degree production at high p perpendicular and in the Λ (Σ degree), π ± , π degree production at large x F , and Δσ L (pp, bar pp) measurements. 18 refs

  17. NUCLEON POLARIZATION IN 3-BODY MODELS OF POLARIZED LI-6

    NARCIS (Netherlands)

    SCHELLINGERHOUT, NW; KOK, LP; COON, SA; ADAM, RM

    1993-01-01

    Just as He-3 --> can be approximately characterized as a polarized neutron target, polarized Li-6D has been advocated as a good isoscalar nuclear target for the extraction of the polarized gluon content of the nucleon. The original argument rests upon a presumed ''alpha + deuteron'' picture of Li-6,

  18. Recent progress on HYSPEC, and its polarization analysis capabilities

    Directory of Open Access Journals (Sweden)

    Winn Barry

    2015-01-01

    Full Text Available HYSPEC is a high-intensity, direct-geometry time-of-flight spectrometer at the Spallation Neutron Source, optimized for measurement of excitations in small single-crystal specimens with optional polarization analysis capabilities. The incident neutron beam is monochromated using a Fermi chopper with short, straight blades, and is then vertically focused by Bragg scattering onto the sample position by either a highly oriented pyrolitic graphite (unpolarized or a Heusler (polarized crystal array. Neutrons are detected by a bank of 3He tubes that can be positioned over a wide range of scattering angles about the sample axis. HYSPEC entered the user program in February 2013 for unpolarized experiments, and is already experiencing a vibrant research program. Polarization analysis will be accomplished by using the Heusler crystal array to polarize the incident beam, and either a 3He spin filter or a supermirror wide-angle polarization analyser to analyse the scattered beam. The 3He spin filter employs the spin-exchange optical pumping technique. A 60∘ wide angle 3He cell that matches the detector coverage will be used for polarization analysis. The polarized gas in the post-sample wide angle cell is designed to be periodically and automatically refreshed with an adjustable pressure of polarized gas, optically pumped in a separate cell and then transferred to the wide angle cell. The supermirror analyser has 960 supermirror polarizers distributed over 60∘, and has been characterized at the Swiss Spallation Neutron Source. The current status of the instrument and the development of its polarization analysis capabilities are presented.

  19. Source of spin polarized electrons

    International Nuclear Information System (INIS)

    Pierce, D.T.; Meier, F.A.; Siegmann, H.C.

    1976-01-01

    A method is described of producing intense beams of polarized free electrons in which a semiconductor with a spin orbit split valence band and negative electron affinity is used as a photocathode and irradiated with circularly polarized light

  20. Linearly polarized photons at ELSA

    Energy Technology Data Exchange (ETDEWEB)

    Eberhardt, Holger [Physikalisches Institut, Universitaet Bonn (Germany)

    2009-07-01

    To investigate the nucleon resonance regime in meson photoproduction, double polarization experiments are currently performed at the electron accelerator ELSA in Bonn. The experiments make use of a polarized target and circularly or linearly polarized photon beams. Linearly polarized photons are produced by coherent bremsstrahlung from an accurately aligned diamond crystal. The orientation of the crystal with respect to the electron beam is measured using the Stonehenge-Technique. Both, the energy of maximum polarization and the plane of polarization, can be deliberately chosen for the experiment. The linearly polarized beam provides the basis for the measurement of azimuthal beam asymmetries, such as {sigma} (unpolarized target) and G (polarized target). These observables are extracted in various single and multiple meson photoproduction channels.

  1. Instrumentation a reader

    CERN Document Server

    Pope, P

    1990-01-01

    This book contains a selection of papers and articles in instrumentation previously pub­ lished in technical periodicals and journals of learned societies. Our selection has been made to illustrate aspects of current practice and applications of instrumentation. The book does not attempt to be encyclopaedic in its coverage of the subject, but to provide some examples of general transduction techniques, of the sensing of particular measurands, of components of instrumentation systems and of instrumentation practice in two very different environments, the food industry and the nuclear power industry. We have made the selection particularly to provide papers appropriate to the study of the Open University course T292 Instrumentation. The papers have been chosen so that the book covers a wide spectrum of instrumentation techniques. Because of this, the book should be of value not only to students of instrumen­ tation, but also to practising engineers and scientists wishing to glean ideas from areas of instrumen...

  2. Instrumentation for Nuclear Applications

    International Nuclear Information System (INIS)

    1998-01-01

    The objective of this project was to develop and coordinate nuclear instrumentation standards with resulting economies for the nuclear and radiation fields. There was particular emphasis on coordination and management of the Nuclear Instrument Module (NIM) System, U.S. activity involving the CAMAC international standard dataway system, the FASTBUS modular high-speed data acquisition and control system and processing and management of national nuclear instrumentation and detector standards, as well as a modest amount of assistance and consultation services to the Pollutant Characterization and Safety Research Division of the Office of Health and Environmental Research. The principal accomplishments were the development and maintenance of the NIM instrumentation system that is the predominant instrumentation system in the nuclear and radiation fields worldwide, the CAMAC digital interface system in coordination with the ESONE Committee of European Laboratories, the FASTBUS high-speed system and numerous national and international nuclear instrumentation standards

  3. VIRUS instrument enclosures

    Science.gov (United States)

    Prochaska, T.; Allen, R.; Mondrik, N.; Rheault, J. P.; Sauseda, M.; Boster, E.; James, M.; Rodriguez-Patino, M.; Torres, G.; Ham, J.; Cook, E.; Baker, D.; DePoy, Darren L.; Marshall, Jennifer L.; Hill, G. J.; Perry, D.; Savage, R. D.; Good, J. M.; Vattiat, Brian L.

    2014-08-01

    The Visible Integral-Field Replicable Unit Spectrograph (VIRUS) instrument will be installed at the Hobby-Eberly Telescope† in the near future. The instrument will be housed in two enclosures that are mounted adjacent to the telescope, via the VIRUS Support Structure (VSS). We have designed the enclosures to support and protect the instrument, to enable servicing of the instrument, and to cool the instrument appropriately while not adversely affecting the dome environment. The system uses simple HVAC air handling techniques in conjunction with thermoelectric and standard glycol heat exchangers to provide efficient heat removal. The enclosures also provide power and data transfer to and from each VIRUS unit, liquid nitrogen cooling to the detectors, and environmental monitoring of the instrument and dome environments. In this paper, we describe the design and fabrication of the VIRUS enclosures and their subsystems.

  4. Stanford polarized atomic beam target

    International Nuclear Information System (INIS)

    Mavis, D.G.; Dunham, J.S.; Hugg, J.W.; Glavish, H.F.

    1976-01-01

    A polarized atomic beam source was used to produce an atomic hydrogen beam which was in turn used as a polarized proton target. A target density of 2 x 10'' atoms/cm 3 and a target polarization of 0.37 without the use of rf transitions were measured. These measurements indicate that a number of experiments are currently feasible with a variety of polarized target beams

  5. Polarization information processing and software system design for simultaneously imaging polarimetry

    Science.gov (United States)

    Wang, Yahui; Liu, Jing; Jin, Weiqi; Wen, Renjie

    2015-08-01

    Simultaneous imaging polarimetry can realize real-time polarization imaging of the dynamic scene, which has wide application prospect. This paper first briefly illustrates the design of the double separate Wollaston Prism simultaneous imaging polarimetry, and then emphases are put on the polarization information processing methods and software system design for the designed polarimetry. Polarization information processing methods consist of adaptive image segmentation, high-accuracy image registration, instrument matrix calibration. Morphological image processing was used for image segmentation by taking dilation of an image; The accuracy of image registration can reach 0.1 pixel based on the spatial and frequency domain cross-correlation; Instrument matrix calibration adopted four-point calibration method. The software system was implemented under Windows environment based on C++ programming language, which realized synchronous polarization images acquisition and preservation, image processing and polarization information extraction and display. Polarization data obtained with the designed polarimetry shows that: the polarization information processing methods and its software system effectively performs live realize polarization measurement of the four Stokes parameters of a scene. The polarization information processing methods effectively improved the polarization detection accuracy.

  6. One directional polarized neutron reflectometry with optimized reference layer method

    International Nuclear Information System (INIS)

    Masoudi, S. Farhad; Jahromi, Saeed S.

    2012-01-01

    In the past decade, several neutron reflectometry methods for determining the modulus and phase of the complex reflection coefficient of an unknown multilayer thin film have been worked out among which the method of variation of surroundings and reference layers are of highest interest. These methods were later modified for measurement of the polarization of the reflected beam instead of the measurement of the intensities. In their new architecture, these methods not only suffered from the necessity of change of experimental setup but also another difficulty was added to their experimental implementations. This deficiency was related to the limitations of the technology of the neutron reflectometers that could only measure the polarization of the reflected neutrons in the same direction as the polarization of the incident beam. As the instruments are limited, the theory has to be optimized so that the experiment could be performed. In a recent work, we developed the method of variation of surroundings for one directional polarization analysis. In this new work, the method of reference layer with polarization analysis has been optimized to determine the phase and modulus of the unknown film with measurement of the polarization of the reflected neutrons in the same direction as the polarization of the incident beam.

  7. Modulus design multiwavelength polarization microscope for transmission Mueller matrix imaging.

    Science.gov (United States)

    Zhou, Jialing; He, Honghui; Chen, Zhenhua; Wang, Ye; Ma, Hui

    2018-01-01

    We have developed a polarization microscope based on a commercial transmission microscope. We replace the halogen light source by a collimated LED light source module of six different colors. We use achromatic polarized optical elements that can cover the six different wavelength ranges in the polarization state generator (PSG) and polarization state analyzer (PSA) modules. The dual-rotating wave plate method is used to measure the Mueller matrix of samples, which requires the simultaneous rotation of the two quarter-wave plates in both PSG and PSA at certain angular steps. A scientific CCD detector is used as the image receiving module. A LabView-based software is developed to control the rotation angels of the wave plates and the exposure time of the detector to allow the system to run fully automatically in preprogrammed schedules. Standard samples, such as air, polarizers, and quarter-wave plates, are used to calibrate the intrinsic Mueller matrix of optical components, such as the objectives, using the eigenvalue calibration method. Errors due to the images walk-off in the PSA are studied. Errors in the Mueller matrices are below 0.01 using air and polarizer as standard samples. Data analysis based on Mueller matrix transformation and Mueller matrix polarization decomposition is used to demonstrate the potential application of this microscope in pathological diagnosis. (2018) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

  8. Radiation protection instrument 1993

    International Nuclear Information System (INIS)

    1993-04-01

    The Radiation Protection Instrument, 1993 (Legislative Instrument 1559) prescribes the powers and functions of the Radiation Protection Board established under the Ghana Atomic Energy Commission by the Atomic Energy Commission (Amendment) Law, 1993 (P.N.D.C. Law 308). Also included in the Legislative Instrument are schedules on control and use of ionising radiation and radiation sources as well as procedures for notification, licensing and inspection of ionising radiation facilities. (EAA)

  9. Three-photon polarization ququarts: polarization, entanglement and Schmidt decompositions

    International Nuclear Information System (INIS)

    Fedorov, M V; Miklin, N I

    2015-01-01

    We consider polarization states of three photons, propagating collinearly and having equal given frequencies but with arbitrary distributed horizontal or vertical polarizations of photons. A general form of such states is a superposition of four basic three-photon polarization modes, to be referred to as the three-photon polarization ququarts (TPPQ). All such states can be considered as consisting of one- and two-photon parts, which can be entangled with each other. The degrees of entanglement and polarization, as well as the Schmidt decomposition and Stokes vectors of TPPQ are found and discussed. (paper)

  10. Networked Instrumentation Element

    Data.gov (United States)

    National Aeronautics and Space Administration — Armstrong researchers have developed a networked instrumentation system that connects modern experimental payloads to existing analog and digital communications...

  11. Instrument validation project

    International Nuclear Information System (INIS)

    Reynolds, B.A.; Daymo, E.A.; Geeting, J.G.H.; Zhang, J.

    1996-06-01

    Westinghouse Hanford Company Project W-211 is responsible for providing the system capabilities to remove radioactive waste from ten double-shell tanks used to store radioactive wastes on the Hanford Site in Richland, Washington. The project is also responsible for measuring tank waste slurry properties prior to injection into pipeline systems, including the Replacement of Cross-Site Transfer System. This report summarizes studies of the appropriateness of the instrumentation specified for use in Project W-211. The instruments were evaluated in a test loop with simulated slurries that covered the range of properties specified in the functional design criteria. The results of the study indicate that the compact nature of the baseline Project W-211 loop does not result in reduced instrumental accuracy resulting from poor flow profile development. Of the baseline instrumentation, the Micromotion densimeter, the Moore Industries thermocouple, the Fischer and Porter magnetic flow meter, and the Red Valve Pressure transducer meet the desired instrumental accuracy. An alternate magnetic flow meter (Yokagawa) gave nearly identical results as the baseline fischer and Porter. The Micromotion flow meter did not meet the desired instrument accuracy but could potentially be calibrated so that it would meet the criteria. The Nametre on-line viscometer did not meet the desired instrumental accuracy and is not recommended as a quantitative instrument although it does provide qualitative information. The recommended minimum set of instrumentation necessary to ensure the slurry meets the Project W-058 acceptance criteria is the Micromotion mass flow meter and delta pressure cells

  12. Instrument performance evaluation

    International Nuclear Information System (INIS)

    Swinth, K.L.

    1993-03-01

    Deficiencies exist in both the performance and the quality of health physics instruments. Recognizing the implications of such deficiencies for the protection of workers and the public, in the early 1980s the DOE and the NRC encouraged the development of a performance standard and established a program to test a series of instruments against criteria in the standard. The purpose of the testing was to establish the practicality of the criteria in the standard, to determine the performance of a cross section of available instruments, and to establish a testing capability. Over 100 instruments were tested, resulting in a practical standard and an understanding of the deficiencies in available instruments. In parallel with the instrument testing, a value-impact study clearly established the benefits of implementing a formal testing program. An ad hoc committee also met several times to establish recommendations for the voluntary implementation of a testing program based on the studies and the performance standard. For several reasons, a formal program did not materialize. Ongoing tests and studies have supported the development of specific instruments and have helped specific clients understand the performance of their instruments. The purpose of this presentation is to trace the history of instrument testing to date and suggest the benefits of a centralized formal program

  13. [Controlling instruments in radiology].

    Science.gov (United States)

    Maurer, M

    2013-10-01

    Due to the rising costs and competitive pressures radiological clinics and practices are now facing, controlling instruments are gaining importance in the optimization of structures and processes of the various diagnostic examinations and interventional procedures. It will be shown how the use of selected controlling instruments can secure and improve the performance of radiological facilities. A definition of the concept of controlling will be provided. It will be shown which controlling instruments can be applied in radiological departments and practices. As an example, two of the controlling instruments, material cost analysis and benchmarking, will be illustrated.

  14. Ocean Optics Instrumentation Systems

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Provides instrumentation suites for a wide variety of measurements to characterize the ocean’s optical environment. These packages have been developed to...

  15. Polarization effects in hadron fragmentation

    International Nuclear Information System (INIS)

    Lednicky, R.

    1984-01-01

    Hadron polarization (spin alignment) and polarization asymmetry are discussed in terms of the quark recombination model with the spin-orbit interaction taken into account. It is shown that predictions of this model are at least in qualitative agreement with experimental data. Various polarization mechanisms in terms of this model and the possibility of their checking are also discussed

  16. Detection of polar vapours

    International Nuclear Information System (INIS)

    Blyth, D.A.

    1980-01-01

    Apparatus for monitoring for polar vapours in a gas consists of (i) a body member defining a passage through which a continuous stream of the gas passes; (ii) an ionising source associated with a region of the passage such that ionization of the gas stream takes place substantially only within the region and also any polar vapour molecules present therein will react with the gas formed to generate ion clusters; and (iii) an electrode for collecting ions carried by the gas stream, the electrode being positioned in the passage downstream of the region and separated from the region by a sufficient distance to ensure that no substantial number of the gas ions formed in said region remains in the gas stream at the collector electrode whilst ensuring that a substantial proportion of the ion clusters formed in the region does remain in the gas stream at the collector electrode. (author)

  17. Perspectives for polarized antiprotons

    International Nuclear Information System (INIS)

    Lenisa, Paolo

    2012-01-01

    Polarized antiprotons would open a new window in hadron physics providing access to a wealth of single and double spin observables in proton-antiproton interactions. The PAX Collaboration aims to perform the first ever measurement of the spin-dependence of the proton-antiproton cross section at the AD ring at CERN. The spin-dependence of the cross section could in principle be exploited by the spin-filtering technique for the production of a polarized antiproton beam. As a preparatory phase to the experimentation at AD, the PAX Collaboration has initiated a series of dedicated studies with protons at the COSY-ring in Juelich (Germany), aimed at the commissioning of the experimental apparatus and confirmation of the predictions for spin-filtering with protons.

  18. The Polar Cusp

    International Nuclear Information System (INIS)

    Holtet, J.A.; Egeland, A.

    1985-01-01

    The upper atmosphere at high latitudes is often called the ''earth's window to outer space.'' Through various electrodynamic coupling processes, as well as direct transfer of particles, many of the geophysical effects displayed are direct manifestations of phenomena occurring in deep space. The high latitude ionosphere also exerts a feedback on the regions of the magnetosphere and atmosphere to which it is coupled. Of particular interest are the sections of the near space known as the Polar Cusp. A vast portion of the Earth's magnetic field envelope is electrically connected to these regions. This geometry results in a spatial mapping of the magnetospheric processes and a focusing on the ionosphere. In the Polar Cusps, the solar wind plasma also has direct access to the upper atmosphere

  19. Polarized electrogowdy spacetimes censored

    International Nuclear Information System (INIS)

    Nungesser, Ernesto

    2010-01-01

    A sketch of the proof of strong cosmic censorship is presented for a class of solutions of the Einstein-Maxwell equations, those with polarized Gowdy symmetry. A key element of the argument is the observation that by means of a suitable choice of variables the central equations in this problem can be written in a form where they are identical to the central equations for general (i.e. non-polarized) vacuum Gowdy spacetimes. Using this it is seen that the results of Ringstroem on strong cosmic censorship in the vacuum case have implications for the Einstein-Maxwell case. Working out the geometrical meaning of these analytical results leads to the main conclusion.

  20. Polarized electrogowdy spacetimes censored

    Energy Technology Data Exchange (ETDEWEB)

    Nungesser, Ernesto, E-mail: ernesto.nungesser@aei.mpg.d [Max-Planck-Institut fuer Gravitationsphysik, Albert-Einstein-Institut, Am Muehlenberg 1, 14476 Potsdam (Germany)

    2010-05-01

    A sketch of the proof of strong cosmic censorship is presented for a class of solutions of the Einstein-Maxwell equations, those with polarized Gowdy symmetry. A key element of the argument is the observation that by means of a suitable choice of variables the central equations in this problem can be written in a form where they are identical to the central equations for general (i.e. non-polarized) vacuum Gowdy spacetimes. Using this it is seen that the results of Ringstroem on strong cosmic censorship in the vacuum case have implications for the Einstein-Maxwell case. Working out the geometrical meaning of these analytical results leads to the main conclusion.

  1. Polarization of lanthanum nucleus by dynamic polarization method

    International Nuclear Information System (INIS)

    Adachi, Toshikazu; Ishimoto, Shigeru; Masuda, Yasuhiro; Morimoto, Kimio

    1989-01-01

    Preliminary studies have been carried out concerning the application of a dynamic polarization method to polarizing lanthanum fluoride single crystal to be employed as target in experiments with time reversal invariance. The present report briefly outlines the dynamic polarization method and describes some preliminary studies carried out so far. Dynamic polarization is of particular importance because no techniques are currently available that can produce highly polarized static nucleus. Spin interaction between electrons and protons (nuclei) plays a major role in the dynamic polarization method. In a thermal equilibrium state, electrons are polarized almost completely while most protons are not polarized. Positively polarized proton spin is produced by applying microwave to this system. The most hopeful candidate target material is single crystal of LaF 3 containing neodymium because the crystal is chemically stable and easy to handle. The spin direction is of great importance in experiments with time reversal invariance. The spin of neutrons in the target can be cancelled by adjusting the external magnetic field applied to a frozen polarized target. In a frozen spin state, the polarity decreases slowly with a relaxation time that depends on the external magnetic field and temperature. (N.K.)

  2. Polar bears, Ursus maritimus

    Science.gov (United States)

    Rode, Karyn D.; Stirling, Ian

    2017-01-01

    Polar bears are the largest of the eight species of bears found worldwide and are covered in a pigment-free fur giving them the appearance of being white. They are the most carnivorous of bear species consuming a high-fat diet, primarily of ice-associated seals and other marine mammals. They range throughout the circumpolar Arctic to the southernmost extent of seasonal pack ice.

  3. Polarized advanced fuel reactors

    International Nuclear Information System (INIS)

    Kulsrud, R.M.

    1987-07-01

    The d- 3 He reaction has the same spin dependence as the d-t reaction. It produces no neutrons, so that if the d-d reactivity could be reduced, it would lead to a neutron-lean reactor. The current understanding of the possible suppression of the d-d reactivity by spin polarization is discussed. The question as to whether a suppression is possible is still unresolved. Other advanced fuel reactions are briefly discussed. 11 refs

  4. Polish polar research (outline

    Directory of Open Access Journals (Sweden)

    Krzysztof Ludwik Birkenmajer

    2017-12-01

    Full Text Available The article describes Polish research and discoveries in the Arctic and the Antarctic since the 19th century. The author is a geologist and since 1956 has been engaged in scientific field research on Spitsbergen, Greenland and Antarctica (23 expeditions. For many years chairman of the Committee on Polar Research of the Polish Academy of Sciences, he is now its Honorary Chairman.

  5. South Polar Polygons

    Science.gov (United States)

    2005-01-01

    4 July 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a polgyon-cracked surface, into which deep, somewhat kidney-bean-shaped pits have formed. These are landscapes of the martian south polar residual cap. This view was captured during May 2005. Location near: 86.9oS, 5.1oW Image width: 1.5 km (0.9 mi) Illumination from: upper left Season Southern Spring

  6. Novel polar sedimentary porphyrins

    Science.gov (United States)

    Prowse, W. G.; Maxwell, J. R.

    1989-11-01

    Two polar nickel porphyrins in Messel oil shale are shown to be the C 32 and C 30 components IIIa,b. In the sample examined, component IIIa is by far the major porphyrin alcohol and is present in an abundance similar to that of the major nickel alkyl porphyrin. These primary alcohols, which do not appear to be artifacts, are structurally related to alkyl porphyrins reported previously in Serpiano oil shale.

  7. Polarization properties of linearly polarized parabolic scaling Bessel beams

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Mengwen; Zhao, Daomu, E-mail: zhaodaomu@yahoo.com

    2016-10-07

    The intensity profiles for the dominant polarization, cross polarization, and longitudinal components of modified parabolic scaling Bessel beams with linear polarization are investigated theoretically. The transverse intensity distributions of the three electric components are intimately connected to the topological charge. In particular, the intensity patterns of the cross polarization and longitudinal components near the apodization plane reflect the sign of the topological charge. - Highlights: • We investigated the polarization properties of modified parabolic scaling Bessel beams with linear polarization. • We studied the evolution of transverse intensity profiles for the three components of these beams. • The intensity patterns of the cross polarization and longitudinal components can reflect the sign of the topological charge.

  8. Applications of polarized neutrons

    International Nuclear Information System (INIS)

    Mezei, F.

    1993-01-01

    The additional spin degree of freedom of the neutron can be made use of in neutron scattering work in two fundamental ways: (a) directly for the identification of magnetic scattering effects and (b) indirectly as a spectroscopic tool for modulating and analysing beams. Although strong magnetic scattering contributions can often be studied by unpolarized neutrons, a fully unambiguous separation of nuclear and magnetic phenomena can only be achieved by the additional information provided by polarized neutrons, especially if one of the two kinds of contributions is weak compared to the other. In the most general case a sample with both magnetic and nuclear features can be characterized by as many as 16 independent dynamic correlation functions instead of the single well known S(q, ω) for non-magnetic nuclear scattering only. Polarization analysis in principle allows one to determine all these 16 functions. The indirect applications of polarized neutrons are also steadily gaining importance. The most widely used method of this kind, the application of Larmor precessions for high resolution energy analysis in Neutron Spin Echo spectroscopy opened up a whole new domain in inelastic neutron scattering which was not accessible to any other spectroscopic method with or without neutrons before. (author)

  9. Pliocene geomagnetic polarity epochs

    Science.gov (United States)

    Dalrymple, G.B.; Cox, A.; Doell, Richard R.; Gromme, C.S.

    1967-01-01

    A paleomagnetic and K-Ar dating study of 44 upper Miocene and Pliocene volcanic units from the western United States suggests that the frequency of reversals of the earth's magnetic field during Pliocene time may have been comparable with that of the last 3.6 m.y. Although the data are too limited to permit the formal naming of any new polarity epochs or events, four polarity transitions have been identified: the W10 R/N boundary at 3.7 ?? 0.1 m.y., the A12 N/R boundary at 4.9 ?? 0.1 m.y., the W32 N/R boundary at 9.0 ?? 0.2m.y., and the W36 R/N boundary at 10.8 ?? 0.3 - 1.0 m.y. The loss of absolute resolution of K-Ar dating in older rocks indicates that the use of well defined stratigraphic successions to identify and date polarity transitions will be important in the study of Pliocene and older reversals. ?? 1967.

  10. The neutron instrument simulation package, NISP

    International Nuclear Information System (INIS)

    Seeger, P.A.; Daemen, L.L.

    2004-01-01

    The Neutron Instrument Simulation Package (NISP) performs complete source-to-detector simulations of neutron instruments, including neutrons that do not follow the expected path. The original user interface (MC( ) Web) is a web-based application, http://strider.lansce.lanl.gov/NISP/Welcome.html. This report describes in detail the newer standalone Windows version, NISP( ) Win. Instruments are assembled from menu-selected elements, including neutron sources, collimation and transport elements, samples, analyzers, and detectors. Magnetic field regions may also be specified for the propagation of polarized neutrons including spin precession. Either interface writes a geometry file that is used as input to the Monte Carlo engine (MC( ) Run) in the user's computer. Both the interface and the engine rely on a subroutine library, MCLIB. The package is completely open source. New features include capillary optics, temperature dependence of Al and Be, revised source files for ISIS, and visualization of neutron trajectories at run time. Also, a single-crystal sample type has been successfully imported from McStas (with more generalized geometry), demonstrating the capability of including algorithms from other sources, and NISP( ) Win may render the instrument in a virtual reality file. Results are shown for two instruments under development.

  11. Towards helium-3 neutron polarizers

    International Nuclear Information System (INIS)

    Tasset, F.

    1995-01-01

    With a large absorption cross-section entirely due to antiparallel spin capture, polarized helium-3 is presently the most promising broad-band polarizer for thermal and epithermal neutrons. Immediate interest was raised amongst the neutron community when a dense gaseous 3 He polarizer was used for the first time in 1988, on a pulsed neutron beam at Los Alamos. With 20 W of laser power on a 30 cm long, 8.6 atm target, 40% 3 He polarization was achieved in a recent polarized electron scattering experiment at SLAC. In this technique the 3 He nuclei are polarized directly at an appropriate high pressure through spin-exchange collisions with a thick, optically pumped rubidium vapor. A different and competitive approach is being presently developed at Mainz University in collaboration with ENS Paris and now the ILL. A discharge is established in pure 3 He at low pressure producing excited metastable atoms which can be optically pumped with infra-red light. Highly effective exchange collision with the atoms remaining in the ground state quickly produces 75% polarization at 1.5 mbar. A truly non-magnetic system then compresses the polarized gas up to several bars as required. The most recent machine comprises a two-stage glass-titanium compressor. In less than 1 h it can inflate a 100 cm 3 target cell with three bars of polarized gas. The very long relaxation times (several days) now being obtained at high pressure with a special metallic coating on the glass walls, the polarized cell can be detached and inserted in the neutron beam as polarizer. We expect 50% 3 He-polarization to be reached soon, allowing such filters to compete favorably with existing Heusler-crystal polarizers at thermal and short neutron wavelengths. It must be stressed that such a system based on a 3 He polarization factory able to feed several passive, transportable, polarizers is well matched to neutron scattering needs. (orig.)

  12. Purging sensitive science instruments with nitrogen in the STS environment

    Science.gov (United States)

    Lumsden, J. M.; Noel, M. B.

    1983-01-01

    Potential contamination of extremely sensitive science instruments during prelaunch, launch, and earth orbit operations are a major concern to the Galileo and International Solar Polar Mission (ISPM) Programs. The Galileo Program is developing a system to purify Shuttle supplied nitrogen gas for in-flight purging of seven imaging and non-imaging science instruments. Monolayers of contamination deposited on critical surfaces can degrade some instrument sensitivities as much as fifty percent. The purging system provides a reliable supply of filtered and fried nitrogen gas during these critical phases of the mission when the contamination potential is highest. The Galileo and ISPM Programs are including the system as Airborne Support Equipment (ASE).

  13. Overview of LOFT instrumentation

    International Nuclear Information System (INIS)

    Bixby, W.W.

    1979-01-01

    A description of instrumentation used in the Loss-of-Fluid Test (LOFT) large break Loss-of-Coolant Experiments is presented. Emphasis is placed on hydraulic and thermal measurements in the primary system piping and components, reactor vessel, and pressure suppression system. In addition, instrumentation which is being considered for measurement of phenomena during future small break testing is discussed

  14. Review of polarized ammonium target

    International Nuclear Information System (INIS)

    Matsuda, Tatsuo

    1987-01-01

    Recently, ammonia (NH 3 ) and deutron ammonia (ND 3 ), instead of conventional alcohol substances, have been used more frequently as a polarized target substance for experiments of polarization at high energy regions. This article reviews major features of the polarized (deutron) ammonia targets. The dynamic nuclear polarization (DNT) method is widely used in high energy polarization experiments. While only a low polarization degree of hydrogen nucleus of 1.7 percent can be obtained by the Brute force method, DNP can produce polarization as high as ∼ 90 percent (2.5 T, ∼ 200 mK). In 1979, ammonia was irradiated with radiations to form NH 2 free radicals, resulting in the achievement of a high polarization degree of greater than 90 percent (hydrogen). Since then, ammonia and deutron ammonia have increasingly been replacing alcohols including butanol. Irradiation of a target substance with radiations destroys the structure of the substance, leading to a decrease in polarization degree. However, ammonia produces unpaired electrons as a result of irradiation, allowing it to be highly resistant to radiation. This report also present some study results, including observations on effects of radiation on the polarization degree of a target, effects of annealing, and polarization of 14 N. A process for producing an ammonia target is also described. (Nogami, K.)

  15. A Si nanocube array polarizer

    Science.gov (United States)

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

    2017-10-01

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

  16. Polarization: A must for fusion

    Directory of Open Access Journals (Sweden)

    Didelez J.-P.

    2013-11-01

    Full Text Available The complete polarization of DT fuel would increase the fusion reactivity by 50% in magnetic as well as in inertial confinements. The persistence of polarization in a fusion process could be tested, using a terawatt laser hitting a polarized HD target. The polarized deuterons heated in the plasma induced by the laser can fuse producing a 3He and a neutron in the final state. The angular distribution of the emitted neutrons and the change in the corresponding total Cross Section (CS can sign the polarization persistence. The polarization of solid H2, D2 or T2 Hydrogen isotopes is very difficult. However, it has been possible to polarize HD, a hetero-molecular form of Hydrogen, by static polarization, at very low temperature and very high field. The radioactivity of DT molecules forbids there high polarization by the static method, therefore one has to develop the Dynamic Nuclear Polarization (DNP by RF transitions. The DNP of HD has been investigated in the past. The magnetic properties of HD and DT molecules are very similar, it is therefore expected that any polarization result obtained with HD could be extrapolated to DT.

  17. Elite Polarization and Public Opinion

    DEFF Research Database (Denmark)

    Robison, Joshua; Mullinix, Kevin

    2016-01-01

    Elite polarization has reshaped American politics and is an increasingly salient aspect of news coverage within the United States. As a consequence, a burgeoning body of research attempts to unravel the effects of elite polarization on the mass public. However, we know very little about how...... polarization is communicated to the public by news media. We report the results of one of the first content analyses to delve into the nature of news coverage of elite polarization. We show that such coverage is predominantly critical of polarization. Moreover, we show that unlike coverage of politics focused...... on individual politicians, coverage of elite polarization principally frames partisan divisions as rooted in the values of the parties rather than strategic concerns. We build on these novel findings with two survey experiments exploring the influence of these features of polarization news coverage on public...

  18. The polarization of fast neutrons

    International Nuclear Information System (INIS)

    Talov, V.V.

    2001-01-01

    It is insufficient to know coordinates and momentum to describe a state of a neutron. It is necessary to define a spin orientation. As far as it is known from quantum mechanics, a half spin has a projection in the positive direction or in the negative direction. The probability of both projections in an unpolarized beam is equal. If a direction exists, in which the projection is more probably then beam is called polarized in this direction. It is essential to know polarization of neutrons for characteristics of a neutron source, which is emitting it. The question of polarization of fast neutrons came up in 50's. The present work is the review of polarization of fast neutrons and methods of polarization analysis. This also includes information about polarization of fast neutrons from first papers, which described polarization in the D(d,n) 3 He, 7 Li (p,n) 7 Be, T(p,n) 3 He reactions. (authors)

  19. Well logging instrumental and methodological research

    International Nuclear Information System (INIS)

    Andrassy, L.; Barath, I.; Dorko, R.

    1983-01-01

    This part of the Annual Report of the Roland Eoetvoes Geophysical Institute (ELGI) of Hungary for 1982, summarizes the well logging instrumental and methodological researches of ELGI. The theoretical neutron diffusion fluxes for black and brown coals of Hungarian mines were calculated. A coal probe was developed and tested in boreholes using computerized data processing and interpretation. An X-ray radiometric method was used for the determination of Cu and Fe contents of minerals. Researches in the field of magnetic susceptibility and induced polarization logging are also summarized. A rapid analyzer for bauxite mining and a photorecorder for petroleum industry were developed by ELGI. (D.Gy.)

  20. UV ionospheric remote sensing with the Polar BEAR satellite

    International Nuclear Information System (INIS)

    Delgreco, F.P.; Eastes, R.W.; Huffman, R.E.

    1989-01-01

    The Polar BEAR satellite carries the Auroral Ionospheric Remote Sensor (AIRS) instrument, which is designed to return four simultaneous images of atmospheric radiation at northern latitudes, has thus far yielded over 5000 images. Polar BEAR was in operation during March, 1987, when the preliminary K(p) reached a value of 9 over a six-hour period; at that time, AIRS was operating at the 1304 A atomic oxygen wavelength and recorded remarkable data, which are here presented. Due to the intense activity, the AIRS data were barely able to register the poleward edge of the aurora. 6 refs

  1. Astronomy in Denver: Probing Interstellar Circular Polarization with Polvis, a Full Stokes Single Shot Polarimeter

    Science.gov (United States)

    Wolfe, Tristan; Stencel, Robert E.

    2018-06-01

    Measurements of optical circular polarization (Stokes V) introduced by dust grains in the ISM are important for two main reasons. First of all, the polarization itself contains information about the metallic versus dielectric composition of the dust grains themselves (H. C. van de Hulst 1957, textbook). Additionally, circular polarization can help constrain the interstellar component of the polarization of any source that may have intrinsic polarization, which needs to be calibrated for astrophysical study. Though interstellar circular polarization has been observed (P. G. Martin 1972, MNRAS 159), most broadband measurements of ISM polarization include linear polarization only (Stokes Q and U), due to the relatively low circular polarization signal and the added instrumentation complexity of including V-measurement capability. Prior circular polarization measurements have also received very little follow-up in the past several decades, even as polarimeters have become more accurate due to advances in technology. The University of Denver is pursuing these studies with POLVIS, a prototype polarimeter that utilizes a stress-engineered optic ("SEO", A. K. Spilman and T. G. Brown 2007, Applied Optics IP 46) to produce polarization-dependent PSFs (A. M. Beckley and T. G. Brown 2010, Proc SPIE 7570). These PSFs are analyzed to provide simultaneous Stokes I, Q, U, and V measurements, in a single beam and single image, along the line-of-sight to point source-like objects. Polvis is the first polarimeter to apply these optics and measurement techniques for astronomical observations. We present the first results of this instrument in B, V, and R wavebands, providing a fresh look at full Stokes interstellar polarization. Importantly, this set of efforts will constrain the ISM contribution to the polarization with respect to intrinsic stellar components. The authors are grateful to the estate of William Herschel Womble for the support of astronomy at the University of Denver

  2. Coronal Polarization of Pseudostreamers and the Solar Polar Field Reversal

    Science.gov (United States)

    Rachmeler, L. A.; Guennou, C.; Seaton, D. B.; Gibson, S. E.; Auchere, F.

    2016-01-01

    The reversal of the solar polar magnetic field is notoriously hard to pin down due to the extreme viewing angle of the pole. In Cycle 24, the southern polar field reversal can be pinpointed with high accuracy due to a large-scale pseudostreamer that formed over the pole and persisted for approximately a year. We tracked the size and shape of this structure with multiple observations and analysis techniques including PROBA2/SWAP EUV images, AIA EUV images, CoMP polarization data, and 3D tomographic reconstructions. We find that the heliospheric field reversed polarity in February 2014, whereas in the photosphere, the last vestiges of the previous polar field polarity remained until March 2015. We present here the evolution of the structure and describe its identification in the Fe XII 1074nm coronal emission line, sensitive to the Hanle effect in the corona.

  3. System for measuring the proton polarization in a polarized target

    International Nuclear Information System (INIS)

    Karnaukhov, I.M.; Lukhanin, A.A.; Telegin, Yu.N.; Trotsenko, V.I.; Chechetenko, V.F.

    1984-01-01

    The system for measuring the proton polarization in a polarized target representing the high-sensitivity nuclear magnetic resonance (NMR) is described Q-meter with series connection and a circuit for measuring system resonance characteristic is used for NMR-absorption signal recording. Measuring coil is produced of a strip conductor in order to obtain uniform system sensitivity to polarization state in all target volume and improve signal-to-noise ratio. Polarization measuring system operates ion-line with the M-6000 computer. The total measuring error for the value of free proton polarization in target taking into account the error caused by local depolarization of working substance under irradiation by high-intense photon beam is <= 6%. Long-term application of the described system for measuring the proton polarization in the LUEh-20000 accelerator target used in the pion photoproduction experiments has demonstrated its high reliability

  4. Circularly polarized antennas

    CERN Document Server

    Gao, Steven; Zhu, Fuguo

    2013-01-01

    This book presents a comprehensive insight into the design techniques for different types of CP antenna elements and arrays In this book, the authors address a broad range of topics on circularly polarized (CP) antennas. Firstly, it introduces to the reader basic principles, design techniques and characteristics of various types of CP antennas, such as CP patch antennas, CP helix antennas, quadrifilar helix antennas (QHA), printed quadrifilar helix antennas (PQHA), spiral antenna, CP slot antennas, CP dielectric resonator antennas, loop antennas, crossed dipoles, monopoles and CP horns. Adva

  5. Spin-polarized SEM

    International Nuclear Information System (INIS)

    Konoto, Makoto

    2007-01-01

    Development of highly effective evaluation technology of magnetic structures on a nanometric scale is a key to understanding spintronics and related phenomena. A high-resolution spin-polarized scanning electron microscope (spin SEM) developed recently is quite suitable for probing such nanostructures because of the capability of analyzing local magnetization vectors in three dimensions. Utilizing the spin SEM, a layered antiferromagnetic structure with the 1nm-alternation of bilayer-sheet magnetization has been successfully resolved. The real-space imaging with full analysis of the temperature-dependent magnetization vectors will be demonstrated. (author)

  6. Simultaneous observations of sun-aligned polar cap arcs in both hemispheres by EXOS-C and viking

    International Nuclear Information System (INIS)

    Obara, T.; Kitayama, M.; Mukai, T.; Kaya, N.; Murphree, J.S.; Cogger, L.L.

    1988-01-01

    On September 25, 1986, the EXOS-C satellite traversed an intense electron precipitation in the southern polar cap, while the Viking satellite simultaneously obtained image data of the polar cap arc in the northern hemisphere. The energy spectrum of the precipitation, measured by instrumentation aboard EXOS-C, was very similar to that of adjacent (typical) auroral arcs, and the precipitation in the southern polar cap was observed in the same local time sector in which the arc was found in the northern polar cap. Observations seem to support the view that the polar cap arc occurs on closed field lines and is conjugate in both hemispheres. copyright American Geophysical Union 1988

  7. Polarization recovery through scattering media.

    Science.gov (United States)

    de Aguiar, Hilton B; Gigan, Sylvain; Brasselet, Sophie

    2017-09-01

    The control and use of light polarization in optical sciences and engineering are widespread. Despite remarkable developments in polarization-resolved imaging for life sciences, their transposition to strongly scattering media is currently not possible, because of the inherent depolarization effects arising from multiple scattering. We show an unprecedented phenomenon that opens new possibilities for polarization-resolved microscopy in strongly scattering media: polarization recovery via broadband wavefront shaping. We demonstrate focusing and recovery of the original injected polarization state without using any polarizing optics at the detection. To enable molecular-level structural imaging, an arbitrary rotation of the input polarization does not degrade the quality of the focus. We further exploit the robustness of polarization recovery for structural imaging of biological tissues through scattering media. We retrieve molecular-level organization information of collagen fibers by polarization-resolved second harmonic generation, a topic of wide interest for diagnosis in biomedical optics. Ultimately, the observation of this new phenomenon paves the way for extending current polarization-based methods to strongly scattering environments.

  8. Instrumentation reference book

    CERN Document Server

    Boyes, Walt

    2002-01-01

    Instrumentation is not a clearly defined subject, having a 'fuzzy' boundary with a number of other disciplines. Often categorized as either 'techniques' or 'applications' this book addresses the various applications that may be needed with reference to the practical techniques that are available for the instrumentation or measurement of a specific physical quantity or quality. This makes it of direct interest to anyone working in the process, control and instrumentation fields where these measurements are essential.* Comprehensive and authoritative collection of technical information* Writte

  9. The latest radiation instrument

    International Nuclear Information System (INIS)

    Kang, Se Sik; Gwon, Dal Gwan; Kim, Gyeong Geum

    2008-08-01

    This book deals with the latest radiation instrument, which is comprised of eight chapters. It explains X rays instrument for medial treatment, X-ray tube instrument and permissible burden with its history, structure and characteristic high voltage apparatus with high voltage rectifier circuit, X-ray control apparatus for medical treatment, X-ray image equipment X-ray television apparatus and CCD 205, X-ray apparatus of install and types, Digital X-ray apparatus with CR 261 and DR 269, performance management on X-ray for medical treatment with its history, necessity and management in the radiation field.

  10. Soil monitoring instrumentation

    International Nuclear Information System (INIS)

    Umbarger, C.J.

    1980-01-01

    The Los Alamos Scientific Laboratory (LASL) has an extensive program for the development of nondestructive assay instrumentation for the quantitative analysis of transuranic (TRU) materials found in bulk solid wastes generated by Department of Energy facilities and by the commercial nuclear power industry. Included are wastes generated in decontamination and decommissioning of outdated nuclear facilities as well as wastes from old waste burial ground exhumation programs. The assay instrumentation is designed to have detection limits below 10 nCi/g wherever practicable. Because of the topic of this workshop, only the assay instrumentation applied specifically to soil monitoring will be discussed here. Four types of soil monitors are described

  11. Soil monitoring instrumentation

    International Nuclear Information System (INIS)

    Umbarger, C.J.

    1981-01-01

    The Los Alamos Scientific Laboratory (LASL) has an extensive program for the development of nondestructive assay instrumentation for the quantitative analysis of transuranic (TRU) materials found in bulk solid wastes generated by Department of Energy facilities and by the commercial nuclear power industry. Included are wastes generated in decontamination and decommissioning of outdated nuclear facilities, as well as from old waste-burial-ground exhumation programs. The assay instrumentation is designed to have detection limits below 10 nCi/g wherever practicable. The assay instrumentation that is applied specifically to soil monitoring is discussed

  12. Jones' instrument technology

    CERN Document Server

    Jones, Ernest Beachcroft; Kingham, Edward G; Radnai, Rudolf

    1985-01-01

    Jones' Instrument Technology, Volume 5: Automatic Instruments and Measuring Systems deals with general trends in automatic instruments and measuring systems. Specific examples are provided to illustrate the principles of such devices. A brief review of a considerable number of standards is undertaken, with emphasis on the IEC625 Interface System. Other relevant standards are reviewed, including the interface and backplane bus standards. This volume is comprised of seven chapters and begins with a short introduction to the principles of automatic measurements, classification of measuring system

  13. Medical instruments in museums

    DEFF Research Database (Denmark)

    Söderqvist, Thomas; Arnold, Ken

    2011-01-01

    This essay proposes that our understanding of medical instruments might benefit from adding a more forthright concern with their immediate presence to the current historical focus on simply decoding their meanings and context. This approach is applied to the intriguingly tricky question of what...... actually is meant by a "medical instrument." It is suggested that a pragmatic part of the answer might lie simply in reconsidering the holdings of medical museums, where the significance of the physical actuality of instruments comes readily to hand....

  14. Peculiarities of annihilation of polarized positronium in polarized media

    International Nuclear Information System (INIS)

    Silenko, A.Ya.

    2005-01-01

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

  15. Can Reliability of Multiple Component Measuring Instruments Depend on Response Option Presentation Mode?

    Science.gov (United States)

    Menold, Natalja; Raykov, Tenko

    2016-01-01

    This article examines the possible dependency of composite reliability on presentation format of the elements of a multi-item measuring instrument. Using empirical data and a recent method for interval estimation of group differences in reliability, we demonstrate that the reliability of an instrument need not be the same when polarity of the…

  16. V4: The Small Angle Scattering Instrument (SANS at BER II

    Directory of Open Access Journals (Sweden)

    Uwe Keiderling

    2016-11-01

    Full Text Available V4 is a small-angle neutron scatting instrument with an accessible range of scattering vector 0.01 nm-1 < Q < 8.5 nm-1. Outstanding features of the instrument are the polarized neutron option and the list mode data acquisition, allowing for time-resolved measurements with µs time resolution.

  17. Digital all-sky polarization imaging of partly cloudy skies.

    Science.gov (United States)

    Pust, Nathan J; Shaw, Joseph A

    2008-12-01

    Clouds reduce the degree of linear polarization (DOLP) of skylight relative to that of a clear sky. Even thin subvisual clouds in the "twilight zone" between clouds and aerosols produce a drop in skylight DOLP long before clouds become visible in the sky. In contrast, the angle of polarization (AOP) of light scattered by a cloud in a partly cloudy sky remains the same as in the clear sky for most cases. In unique instances, though, select clouds display AOP signatures that are oriented 90 degrees from the clear-sky AOP. For these clouds, scattered light oriented parallel to the scattering plane dominates the perpendicularly polarized Rayleigh-scattered light between the instrument and the cloud. For liquid clouds, this effect may assist cloud particle size identification because it occurs only over a relatively limited range of particle radii that will scatter parallel polarized light. Images are shown from a digital all-sky-polarization imager to illustrate these effects. Images are also shown that provide validation of previously published theories for weak (approximately 2%) polarization parallel to the scattering plane for a 22 degrees halo.

  18. Polarized tagged photons

    International Nuclear Information System (INIS)

    Maximon, L.C.; Ganz, Eric; Aniel, Thierry; Miniac, Arlette de.

    1982-03-01

    We consider in detail the differential cross section for polarized bremsstrahlung for angles and energies in the range of interest for a tagging system and derive a high energy, small angle approximation for this cross section. We use these approximations to determine the maxima and minima of the cross sections for these two polarization states, dσperpendicular and dσparallel, and to evaluate these cross sections at the extrema. It is shown that both dσperpendicular and dσparallel have a very sharp dip in the region of small momentum transfers. However, their behavior in the region of the dip, as a function of the azimuthal angle phi, is quite different over most of the photon spectrum. The cross section dσperpendicular behaves similarly to the cross section for unpolarized photons in that as phi increases, the sharp dip vanishes, the minimum fuses with the second maximum, and the cross section then has only a single maximum. In contrast, the sharp dip in the cross section dσparallel remains as phi increases. Coulomb corrections to the Born approximation are considered, and do not fill in these dips

  19. Environment for the instruments

    International Nuclear Information System (INIS)

    Ambro, P.

    1992-01-01

    A properly conditioned AC power supply is necessary for reliable functioning of instruments. Electric mains power is produced primarily for industry, workshops, lighting and household uses. Its quality is adjusted to these uses. In areas sand countries with a fast growing demand for electric power, these requirements are far from being met. Electronic instruments and computers, especially in these countries, need protection against disturbances of the mains supply. A clean and dry environment is needed for reliable functioning and long life of instruments. High humidity, specially at higher temperatures, changes the characteristics of electronic components. Moreover, under these conditions fungal growth causes leakage of currents and corrosion causes poor contacts. The presence of dust enhances these effects. They give rise to malfunction of instruments, particularly of high voltage equipment

  20. CCAT Heterodyne Instrument Development

    Data.gov (United States)

    National Aeronautics and Space Administration — This work will extend and proof-out the design concept for a high pixel count (128 pixels in 2 bands) submillimeter-wave heterodyne receiver array instrument for the...

  1. Environment for the instruments

    Energy Technology Data Exchange (ETDEWEB)

    Ambro, P

    1993-12-31

    A properly conditioned AC power supply is necessary for reliable functioning of instruments. Electric mains power is produced primarily for industry, workshops, lighting and household uses. Its quality is adjusted to these uses. In areas sand countries with a fast growing demand for electric power, these requirements are far from being met. Electronic instruments and computers, especially in these countries, need protection against disturbances of the mains supply. A clean and dry environment is needed for reliable functioning and long life of instruments. High humidity, specially at higher temperatures, changes the characteristics of electronic components. Moreover, under these conditions fungal growth causes leakage of currents and corrosion causes poor contacts. The presence of dust enhances these effects. They give rise to malfunction of instruments, particularly of high voltage equipment

  2. Fiber Optics Instrumentation Development

    Science.gov (United States)

    Chan, Patrick Hon Man; Parker, Allen R., Jr.; Richards, W. Lance

    2010-01-01

    This is a general presentation of fiber optics instrumentation development work being conducted at NASA Dryden for the past 10 years and recent achievements in the field of fiber optics strain sensors.

  3. Nuclear instrument technician training

    International Nuclear Information System (INIS)

    Wollesen, E.S.

    1991-01-01

    This paper reports on Nuclear Instrument Technician (NIT) training that has developed at an accelerated rate over the past three decades. During the 1960's commercial nuclear power plants were in their infancy. For that reason, there is little wonder that NIT training had little structure and little creditability. NIT training, in many early plants, was little more than On-The Job Training (OJT). The seventies brought changes in Instrumentation and Controls as well as emphasis on the requirements for more in depth training and documentation. As in the seventies, the eighties saw not only changes in technologies but tighter requirements, standardized training and the development of accredited Nuclear Instrument Training; thus the conclusion: Nuclear Instrument Training Isn't What It Used To Be

  4. Carbon Footprint Reduction Instruments

    Science.gov (United States)

    This page outlines the major differences between Renewable Energy Certificates (REC) and Project Offsets and what types of claims each instrument allows the organization to make in regards to environmental emissions claims.

  5. Forward instrumentation for ILC detectors

    Energy Technology Data Exchange (ETDEWEB)

    Abramowicz, Halina [Tel Aviv Univ. (Israel); Abusleme, Angel [Stanford Univ., CA (United States); Afanaciev, Konstantin [NCPHEP, Minsk (BY)] (and others)

    2010-09-15

    Two special calorimeters are foreseen for the instrumentation of the very forward region of the ILC detector, a luminometer designed to measure the rate of low angle Bhabha scattering events with a precision better than 10{sup -3} and a low polar angle calorimeter, adjacent to the beam-pipe. The latter will be hit by a large amount of beamstrahlung remnants. The amount and shape of these depositions will allow a fast luminosity estimate and the determination of beam parameters. The sensors of this calorimeter must be radiation hard. Both devices will improve the hermeticity of the detector in the search for new particles. Finely segmented and very compact calorimeters will match the requirements. Due to the high occupancy fast front-end electronics is needed. The design of the calorimeters developed and optimised with Monte Carlo simulations is presented. Sensors and readout electronics ASICs have been designed and prototypes are available. Results on the performance of these major components are summarised. (orig.)

  6. Spin exchange in polarized deuterium

    International Nuclear Information System (INIS)

    Przewoski, B. von; Meyer, H.O.; Balewski, J.; Doskow, J.; Ibald, R.; Pollock, R.E.; Rinckel, T.; Wellinghausen, A.; Whitaker, T.J.; Daehnick, W.W.; Haeberli, W.; Schwartz, B.; Wise, T.; Lorentz, B.; Rathmann, F.; Pancella, P.V.; Saha, Swapan K.; Thoerngren-Engblom, P.

    2003-01-01

    We have measured the vector and tensor polarization of an atomic deuterium target as a function of the target density. The polarized deuterium was produced in an atomic beam source and injected into a storage cell. For this experiment, the atomic beam source was operated without rf transitions, in order to avoid complications from the unknown efficiency of these transitions. In this mode, the atomic beam is vector and tensor polarized and both polarizations can be measured simultaneously. We used a 1.2-cm-diam and 27-cm-long storage cell, which yielded an average target density between 3 and 9x10 11 at/cm 3 . We find that the tensor polarization decreases with increasing target density while the vector polarization remains constant. The data are in quantitative agreement with the calculated effect of spin exchange between deuterium atoms at low field

  7. High energy polarized electron beams

    International Nuclear Information System (INIS)

    Rossmanith, R.

    1987-01-01

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

  8. Polarized proton collider at RHIC

    International Nuclear Information System (INIS)

    Alekseev, I.; Allgower, C.; Bai, M.; Batygin, Y.; Bozano, L.; Brown, K.; Bunce, G.; Cameron, P.; Courant, E.; Erin, S.; Escallier, J.; Fischer, W.; Gupta, R.; Hatanaka, K.; Huang, H.; Imai, K.; Ishihara, M.; Jain, A.; Lehrach, A.; Kanavets, V.; Katayama, T.; Kawaguchi, T.; Kelly, E.; Kurita, K.; Lee, S.Y.; Luccio, A.; MacKay, W.W.; Mahler, G.; Makdisi, Y.; Mariam, F.; McGahern, W.; Morgan, G.; Muratore, J.; Okamura, M.; Peggs, S.; Pilat, F.; Ptitsin, V.; Ratner, L.; Roser, T.; Saito, N.; Satoh, H.; Shatunov, Y.; Spinka, H.; Syphers, M.; Tepikian, S.; Tominaka, T.; Tsoupas, N.; Underwood, D.; Vasiliev, A.; Wanderer, P.; Willen, E.; Wu, H.; Yokosawa, A.; Zelenski, A.N.

    2003-01-01

    In addition to heavy ion collisions (RHIC Design Manual, Brookhaven National Laboratory), RHIC will also collide intense beams of polarized protons (I. Alekseev, et al., Design Manual Polarized Proton Collider at RHIC, Brookhaven National Laboratory, 1998, reaching transverse energies where the protons scatter as beams of polarized quarks and gluons. The study of high energy polarized protons beams has been a long term part of the program at BNL with the development of polarized beams in the Booster and AGS rings for fixed target experiments. We have extended this capability to the RHIC machine. In this paper we describe the design and methods for achieving collisions of both longitudinal and transverse polarized protons in RHIC at energies up to √s=500 GeV

  9. Instrument care: everyone's responsibility

    Directory of Open Access Journals (Sweden)

    Renée du Toit

    2011-12-01

    Full Text Available Everyone working in an ophthalmic operating theatre must be competent in the care, handling, storage, and maintenance of instruments. This will help to improve surgical outcomes, maintain an economic and affordable service for patients, and provide a safe environment for the wellbeing of patients and staff.Including instrument care in theatre courses and in-service training is one way of ensuring staff competence.

  10. Instrument uncertainty predictions

    International Nuclear Information System (INIS)

    Coutts, D.A.

    1991-07-01

    The accuracy of measurements and correlations should normally be provided for most experimental activities. The uncertainty is a measure of the accuracy of a stated value or equation. The uncertainty term reflects a combination of instrument errors, modeling limitations, and phenomena understanding deficiencies. This report provides several methodologies to estimate an instrument's uncertainty when used in experimental work. Methods are shown to predict both the pretest and post-test uncertainty

  11. Experimenting with woodwind instruments

    Science.gov (United States)

    Lo Presto, Michael C.

    2007-05-01

    Simple experiments involving musical instruments of the woodwind family can be used to demonstrate the basic physics of vibrating air columns in resonance tubes using nothing more than straightforward measurements and data collection hardware and software. More involved experimentation with the same equipment can provide insight into the effects of holes in the tubing and other factors that make simple tubes useful as musical instruments.

  12. Maintenance of scientific instruments

    International Nuclear Information System (INIS)

    Lucero, E.

    1986-01-01

    During the last years Colombia has increased the use of nuclear techniques, instruments and equipment in ambitious health programs, as well as in research centers, industry and education; this has resulted in numerous maintenance problems. As an alternative solution IAN has established a Central Maintenance Laboratory for nuclear instruments within an International Atomic Energy Agency program for eight Latin American and nine Asian Countries. Established strategies and some results are detailed in this writing

  13. THE METHODS OF PRODUCING AND ANALYZING POLARIZED NEUTRON BEAMS FOR HYSPEC AT THE SNS

    International Nuclear Information System (INIS)

    SHAPIRO, S.M.; PASSELL, L.; ZALIZNYAK, A.; GHOSH, V.J.; LEONHARDT, W.L.; HAGEN, M.E.

    2005-01-01

    The Hybrid Spectrometer (HYSPEC), under construction at the SNS on beam line 14B, is the only inelastic scattering instrument designed to enable polarization of the incident and the scattered neutron beams. A Heusler monochromator will replace the graphite crystal for producing polarized neutrons. In the scattered beam it is planned to use a collimator--multi-channel supermirror bender array to analyze the polarization of the scattered beam over the final energy range from 5-20 meV. Other methods of polarization analysis under consideration such as transmission filters using He 3 , Sm, and polarized protons are considered. Their performance is estimated and a comparison of the various methods of polarization is made

  14. Depolarization Ratio Profiles Calibration and Observations of Aerosol and Cloud in the Tibetan Plateau Based on Polarization Raman Lidar

    Directory of Open Access Journals (Sweden)

    Guangyao Dai

    2018-03-01

    Full Text Available A brief description of the Water vapor, Cloud and Aerosol Lidar (WACAL system is provided. To calibrate the volume linear depolarization ratio, the concept of “ Δ 90 ° -calibration” is applied in this study. This effective and accurate calibration method is adjusted according to the design of WACAL. Error calculations and analysis of the gain ratio, calibrated volume linear depolarization ratio and particle linear depolarization ratio are provided as well. In this method, the influences of the gain ratio, the rotation angle of the plane of polarization and the polarizing beam splitter are discussed in depth. Two groups of measurements with half wave plate (HWP at angles of (0 ° , 45 ° and (22.5 ° , −22.5 ° are operated to calibrate the volume linear depolarization ratio. Then, the particle linear depolarization ratios measured by WACAL and CALIOP (the Cloud-Aerosol Lidar with Orthogonal Polarization during the simultaneous observations were compared. Good agreements are found. The calibration method was applied in the third Tibetan Plateau Experiment of Atmospheric Sciences (TIPEX III in 2013 and 2014 in China. Vertical profiles of the particle depolarization ratio of clouds and aerosol in the Tibetan Plateau were measured with WACAL in Litang (30.03° N, 100.28° E, 3949 m above sea level (a.s.l. in 2013 and Naqu (31.48° N, 92.06° E, 4508 m a.s.l. in 2014. Then an analysis on the polarizing properties of the aerosol, clouds and cirrus over the Tibetan Plateau is provided. The particle depolarization ratio of cirrus clouds varies from 0.36 to 0.52, with a mean value of 0.44 ± 0.04. Cirrus clouds occurred between 5.2 and 12 km above ground level (a.g.l.. The cloud thickness ranges from 0.12 to 2.55 km with a mean thickness of 1.22 ± 0.70 km. It is found that the particle depolarization ratio of cirrus clouds become larger as the height increases. However, the increase rate of the particle depolarization ratio becomes smaller as

  15. Linear polarization of BY Draconis

    International Nuclear Information System (INIS)

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

    1976-01-01

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

  16. Polarity in Mammalian Epithelial Morphogenesis

    OpenAIRE

    Roignot, Julie; Peng, Xiao; Mostov, Keith

    2013-01-01

    Cell polarity is fundamental for the architecture and function of epithelial tissues. Epithelial polarization requires the intervention of several fundamental cell processes, whose integration in space and time is only starting to be elucidated. To understand what governs the building of epithelial tissues during development, it is essential to consider the polarization process in the context of the whole tissue. To this end, the development of three-dimensional organotypic cell culture model...

  17. The sensitivity of income polarization

    DEFF Research Database (Denmark)

    Hussain, Azhar

    2009-01-01

    This study looks at polarization and its components' sensitivity to assumptions about equivalence scales, income definition, ethical income distribution parameters, and the income accounting period. A representative sample of Danish individual incomes from 1984 to 2002 is utilised. Results show....... Increasing the accounting period confirms the reduction in inequality found for shorter periods, but polarization is virtually unchanged, because income group identification increases. Applying different equivalence scales does not change polarization ranking for different years, but identification ranks...

  18. Polarized Electrons for Linear Colliders

    International Nuclear Information System (INIS)

    Clendenin, J.

    2004-01-01

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

  19. Problems with radiological surveillance instrumentation

    International Nuclear Information System (INIS)

    Swinth, K.L.; Tanner, J.E.; Fleming, D.M.

    1984-09-01

    Many radiological surveillance instruments are in use at DOE facilities throughout the country. These instruments are an essential part of all health physics programs, and poor instrument performance can increase program costs or compromise program effectiveness. Generic data from simple tests on newly purchased instruments shows that many instruments will not meet requirements due to manufacturing defects. In other cases, lack of consideration of instrument use has resulted in poor acceptance of instruments and poor reliability. The performance of instruments is highly variable for electronic and mechanical performance, radiation response, susceptibility to interferences and response to environmental factors. Poor instrument performance in these areas can lead to errors or poor accuracy in measurements

  20. Problems with radiological surveillance instrumentation

    International Nuclear Information System (INIS)

    Swinth, K.L.; Tanner, J.E.; Fleming, D.M.

    1985-01-01

    Many radiological surveillance instruments are in use at DOE facilities throughout the country. These instruments are an essential part of all health physics programs, and poor instrument performance can increase program costs or compromise program effectiveness. Generic data from simple tests on newly purchased instruments shows that many instruments will not meet requirements due to manufacturing defects. In other cases, lack of consideration of instrument use has resulted in poor acceptance of instruments and poor reliability. The performance of instruments is highly variable for electronic and mechanical performance, radiation response, susceptibility to interferences and response to environmental factors. Poor instrument performance in these areas can lead to errors or poor accuracy in measurements

  1. The Inelastic Instrument suite at the SNS

    International Nuclear Information System (INIS)

    Granroth, Garrett E; Abernathy, Douglas L; Ehlers, Georg; Hagen, Mark E; Herwig, Kenneth W; Mamontov, Eugene; Ohl, Michael E; Wildgruber, Christoph U

    2008-01-01

    The instruments in the extensive suite of spectrometers at the SNS are in various stages of installation and commissioning. The Back Scattering Spectrometer (BASIS) is installed and is in commissioning. It's near backscattering analyzer crystals provide the 3 eV resolution as expected. BASIS will enter the user program in the fall of 2007. The ARCS wide angular-range thermal to epithermal neutron spectrometer will come on line in the fall of 2007 followed shortly by the Cold Neutron Chopper Spectrometer. These two direct geometry instruments provide moderate resolution and the ability to trade resolution for flux. In addition both instruments have detector coverage out to 140o to provide a large Q range. The SEQUOIA spectrometer, complete in 2008, is the direct geometry instrument that will provide fine resolution in the thermal to epithermal range. The Spin-Echo spectrometer, to be completed on a similar time scale, will provide the finest energy resolution worldwide. The HYSPEC spectrometer, available no later than 2011, will provide polarized capabilities and optimized flux in the thermal energy range. Finally, the Vision chemical spectrometer will use crystal analyzers to study energy transfers into the epithermal range

  2. Digibaro pressure instrument onboard the Phoenix Lander

    Science.gov (United States)

    Harri, A.-M.; Polkko, J.; Kahanpää, H. H.; Schmidt, W.; Genzer, M. M.; Haukka, H.; Savijarv1, H.; Kauhanen, J.

    2009-04-01

    The Phoenix Lander landed successfully on the Martian northern polar region. The mission is part of the National Aeronautics and Space Administration's (NASA's) Scout program. Pressure observations onboard the Phoenix lander were performed by an FMI (Finnish Meteorological Institute) instrument, based on a silicon diaphragm sensor head manufactured by Vaisala Inc., combined with MDA data processing electronics. The pressure instrument performed successfully throughout the Phoenix mission. The pressure instrument had 3 pressure sensor heads. One of these was the primary sensor head and the other two were used for monitoring the condition of the primary sensor head during the mission. During the mission the primary sensor was read with a sampling interval of 2 s and the other two were read less frequently as a check of instrument health. The pressure sensor system had a real-time data-processing and calibration algorithm that allowed the removal of temperature dependent calibration effects. In the same manner as the temperature sensor, a total of 256 data records (8.53 min) were buffered and they could either be stored at full resolution, or processed to provide mean, standard deviation, maximum and minimum values for storage on the Phoenix Lander's Meteorological (MET) unit.The time constant was approximately 3s due to locational constraints and dust filtering requirements. Using algorithms compensating for the time constant effect the temporal resolution was good enough to detect pressure drops associated with the passage of nearby dust devils.

  3. Proceedings of the Japan-US workshop on plasma polarization spectroscopy and the fourth international symposium on plasma polarization spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Fujimoto, Takashi; Beiersdorfer, Peter [eds.

    2004-07-01

    The international meeting on Plasma Polarization Spectroscopy (PPS) was held at Kyoto University during February 4-6, 2004. This Proceedings book includes the summaries of the talks given in that meeting. Starting with the Overview talk by Csanak, the subjects cover: x-ray polarization experiments on z-pinches (plasma foci), and an x-pinch, a laser-produced plasma in a gas atmosphere, an interpretation of the polarized 1<- 0 x-ray laser line, polarization observation from various laser-produced plasmas including a recombining phase plasma, a report on the on-going project of a laser facility, several polarization observations on magnetically confined plasmas including the Large Helical Device and an ECR plasma, a new laser-induced fluorescence diagnostic method. On atomic physics side given are: various polarization measurements on EBIT, precision spectroscopy on the TEXTOR, user-friendly atomic codes. Instrumentation is also a subject of this book. The 18 of the presented papers are indexed individually. (J.P.N.)

  4. Optical polarization of high-energy BL Lacertae objects

    Science.gov (United States)

    Hovatta, T.; Lindfors, E.; Blinov, D.; Pavlidou, V.; Nilsson, K.; Kiehlmann, S.; Angelakis, E.; Fallah Ramazani, V.; Liodakis, I.; Myserlis, I.; Panopoulou, G. V.; Pursimo, T.

    2016-12-01

    Context. We investigate the optical polarization properties of high-energy BL Lac objects using data from the RoboPol blazar monitoring program and the Nordic Optical Telescope. Aims: We wish to understand if there are differences between the BL Lac objects that have been detected with the current-generation TeV instruments and those objects that have not yet been detected. Methods: We used a maximum-likelihood method to investigate the optical polarization fraction and its variability in these sources. In order to study the polarization position angle variability, we calculated the time derivative of the electric vector position angle (EVPA) change. We also studied the spread in the Stokes Q/I-U/I plane and rotations in the polarization plane. Results: The mean polarization fraction of the TeV-detected BL Lacs is 5%, while the non-TeV sources show a higher mean polarization fraction of 7%. This difference in polarization fraction disappears when the dilution by the unpolarized light of the host galaxy is accounted for. The TeV sources show somewhat lower fractional polarization variability amplitudes than the non-TeV sources. Also the fraction of sources with a smaller spread in the Q/I-U/I plane and a clumped distribution of points away from the origin, possibly indicating a preferred polarization angle, is larger in the TeV than in the non-TeV sources. These differences between TeV and non-TeV samples seem to arise from differences between intermediate and high spectral peaking sources instead of the TeV detection. When the EVPA variations are studied, the rate of EVPA change is similar in both samples. We detect significant EVPA rotations in both TeV and non-TeV sources, showing that rotations can occur in high spectral peaking BL Lac objects when the monitoring cadence is dense enough. Our simulations show that we cannot exclude a random walk origin for these rotations. Conclusions: These results indicate that there are no intrinsic differences in the

  5. Instrument pre-development activities for FLEX

    Science.gov (United States)

    Pettinato, L.; Fossati, E.; Coppo, P. M.; Taiti, A.; Labate, D.; Capanni, A.; Taccola, M.; Bézy, J. L.; Francois, M.; Meynart, R.; Erdmann, L.; Triebel, P.

    2017-09-01

    The FLuorescence Imaging Spectrometer (FLORIS) is the payload of the FLuorescence Explorer Mission (FLEX) of the European Space Agency. The mission objective is to perform quantitative measurements of the solar induced vegetation fluorescence to monitor photosynthetic activity. FLORIS works in a push-broom configuration and it is designed to acquire data in the 500-780 nm spectral range, with a sampling of 0.1 nm in the oxygen bands (759-769 nm and 686- 697 nm) and 0.5-2.0 nm in the red edge, chlorophyll absorption and Photochemical Reflectance Index bands. FLEX will fly in formation with Sentinel-3 to benefit of the measurements made by the Sentinel-3 instruments OLCI and SLSTR, particularly for cloud screening, proper characterization of the atmospheric state and determination of the surface temperature. The instrument concept is based on a common telescope and two modified Offner spectrometers with reflective concave gratings both for the High Resolution (HR) and Low Resolution (LR) spectrometers. In the frame of the instrument pre-development Leonardo Company (I) has built and tested an elegant breadboard of the instrument consisting of the telescope and the HR spectrometer. The development of the LR spectrometer is in charge of OHB System AG (D) and is currently in the manufacturing phase. The main objectives of the activity are: anticipate the development of the instrument and provide early risk retirement of critical components, evaluate the system performances such as imaging quality parameters, straylight, ghost, polarization sensitivity and environmental influences, verify the adequacy of critical tests such as spectral characterization and straylight, define and optimize instrument alignment procedures. Following a brief overview of the FLEX mission, the paper will cover the design and the development of the optics breadboard with emphasis on the results obtained during the tests and the lessons learned for the flight unit.

  6. A polarized alkali ion source

    International Nuclear Information System (INIS)

    Boettger, R.; Tungate, G.; Bauer, B.; Egelhof, P.; Moebius, K.H.; Steffens, E.

    1978-01-01

    The beam foil technique has been applied to detect nuclear vector polarization of a 10 keV 23 Na + beam. The result was about 70% of the atomic beam polarization thus limiting the depolarization by the surface ionizer to at most 30%. In a Coulomb excitation experiment with a tensor polarized 42 MeV 23 Na 7+ beam an effect of 0.011 +- 0.003 was measured yielding a value of t 20 approx. 0.04 for the beam polarization. The depolarization during the acceleration process can be estimated to be about 0.8. (orig.) [de

  7. Polarization preservation in the AGS

    International Nuclear Information System (INIS)

    Ratner, L.G.

    1983-01-01

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

  8. Polarization-preserving holey fibers

    DEFF Research Database (Denmark)

    Broeng, Jes; Mogilevtsev, Dmitri; Libori, Stig E. Barkou

    2001-01-01

    In this work we suggest and discuss a microstructure of air capillaries with elliptical cross-section in a tread of glass that gives opportunity for Creation of polarization-preserving fiber with very small beat length between the fundamental modes of different polarization......In this work we suggest and discuss a microstructure of air capillaries with elliptical cross-section in a tread of glass that gives opportunity for Creation of polarization-preserving fiber with very small beat length between the fundamental modes of different polarization...

  9. The SLAC polarized electron source

    International Nuclear Information System (INIS)

    Tang, H.; Alley, R.; Frisch, J.

    1995-06-01

    The SLAC polarized electron source employs a photocathode DC high voltage gun with a loadlock and a YAG pumped Ti:sapphire laser system for colliding beam experiments or a flash lamp pumped Ti:sapphire laser for fixed target experiments. It uses a thin, strained GaAs(100) photocathode, and is capable of producing a pulsed beam with a polarization of ≥80% and a peak current exceeding 10 A. Its operating efficiency has reached 99%. The physics and technology of producing high polarization electron beams from a GaAs photocathode will be reviewed. The prospects of realizing a polarized electron source for future linear colliders will also be discussed

  10. Dynamic nuclear polarization tests in some polymers for polarized targets

    International Nuclear Information System (INIS)

    Brandt, B. van den; Hautle, P.; Konter, J.A.; Mango, S.; Bunyatova, E.I.

    1998-01-01

    The results of dynamic polarization tests in polyethylene (PE) and ethylene propylene copolymer (EPC), doped with the stable free radical 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO), are presented. Sizable proton polarizations have been achieved in a magnetic field of 2.5 T at a temperature below 0.3 K and 5T at 1 K

  11. Corrosion protection of reusable surgical instruments.

    Science.gov (United States)

    Shah, Sadiq; Bernardo, Mildred

    2002-01-01

    To understand the corrosion properties of surgical scissors, 416 stainless steel disks and custom electrodes were used as simulated surfaces under various conditions. These simulated surfaces were exposed to tap water and 400-ppm synthetic hard water as Ca2CO3 under different conditions. The samples were evaluated by various techniques for corrosion potential and the impact of environmental conditions on the integrity of the passive film. The electrodes were used to monitor the corrosion behavior by potentiodynamic polarization technique in water both in the presence and absence of a cleaning product. The surface topography of the 416 stainless steel disks was characterized by visual observations and scanning electron microscopy (SEM), and the surface chemistry of the passive film on the surface of the scissors was characterized by x-ray photoelectron spectroscopy (XPS). The results suggest that surgical instruments made from 416 stainless steel are not susceptible to uniform corrosion; however, they do undergo localized corrosion. The use of suitable cleaning products can offer protection against localized corrosion during the cleaning step. More importantly, the use of potentiodynamic polarization techniques allowed for a quick and convenient approach to evaluate the corrosion properties of surgical instruments under a variety of simulated-use environmental conditions.

  12. Some emergency instrumentation

    Energy Technology Data Exchange (ETDEWEB)

    Burgess, P H

    1986-10-01

    The widespread release of activity and the resultant spread of contamination after the Chernobyl accident resulted in requests to NRPB to provide instruments for, and expertise in, the measurement of radiation. The most common request was for advice on the usefulness of existing instruments, but Board staff were also involved in their adaptation or in the development of new instruments specially to meet the circumstances of the accident. The accident occurred on 26 April. On 1 May, NRPB was involved at Heathrow Airport in the monitoring of the British students who had returned from Kiev and Minsk. The main purpose was to reassure the students by checking that their persons and belongings did not have significant surface contamination. Additional measurements were also made of iodine activity in thyroid using hand-held detectors or a mobile body monitor. This operation was arranged with the Foreign and Commonwealth Office, which had also received numerous requests for instruments from embassies and consulates in countries close to the scene of the accident. There was concern for the well-being of staff and other United Kingdom nationals who resided in or intended to visit the most affected countries. The board supplied suitable instruments, and the FCO distributed them to embassies. The frequency of environmental monitoring was increased from 29 April in anticipation of contamination and appropriate Board instrumentation was deployed. After the Chernobyl cloud arrived in the UK on 2 May, there were numerous requests from local government, public authorities, private companies and members of the public for information and advice on monitoring equipment and procedures. Some of these requirements could be met with existing equipment but members of the public were usually advised not to proceed. At a later stage, the contamination of foodstuffs and livestock required the development of an instrument capable of detecting low levels of {sup 137}Cs and {sup 134}Cs in food

  13. Polar measurements on profiles

    Energy Technology Data Exchange (ETDEWEB)

    Althaus, D.

    1985-03-01

    Wind tunnel models with a profile depth of t=0.5 m were measured in a laminar wind tunnel by the usual measuring processes. The profile resistance was determined by integration along the width of span. The smooth profiles were examined at Re=0.7/1.0 and 1.5 million. At Re=1.0 million, the position of the changeover points were determined with a stethoscope. Also at this Reynolds number measurements were taken with a trip wire of d=2 mm diameter, directly on the profile nose. The tables contain the co-ordinates of the profiles, the contours, the theoretical speed distributions for 4 different angles of attack, the csub(a)-csub(w) polar measurements and changeover points, and the torque coefficients around the t/4 point. (BR).

  14. Time asymmetry: Polarization and analyzing power in the nuclear reactions

    Energy Technology Data Exchange (ETDEWEB)

    Rioux, C.; Roy, R.; Slobodrian, R.J. (Laval Univ., Quebec City (Canada). Lab. de Physique Nucleaire); Conzett, H.E. (California Univ., Berkeley (USA). Lawrence Berkeley Lab.)

    1983-02-28

    Measurements of the proton polarization in the reactions /sup 7/Li(/sup 3/He, p vector)/sup 9/Be and /sup 9/Be(/sup 3/He, p vector)/sup 11/B and of the analyzing powers of the inverse reactions, initiated by polarized protons at the same c.m. energies, show significant differences which imply the failure of the polarization-analyzing-power theorem and, prima facie, of time-reversal invariance in these reactions. The reaction /sup 2/H(/sup 3/He, p vector)/sup 4/ He and its inverse have also been investigated and show some smaller differences. A discussion of the instrumental asymmetries is presented.

  15. Reactor instrumentation and control

    International Nuclear Information System (INIS)

    Wach, D.; Beraha, D.

    1980-01-01

    The methods for measuring radiation are shortly reviewed. The instrumentation for neutron flux measurement is classified into out-of-core and in-core instrumentation. The out-of-core instrumentation monitors the operational range from the subcritical reactor to full power. This large range is covered by several measurement channels which derive their signals from counter tubes and ionization chambers. The in-core instrumentation provides more detailed information on the power distribution in the core. The self-powered neutron detectors and the aeroball system in PWR reactors are discussed. Temperature and pressure measurement devices are briefly discussed. The different methods for leak detection are described. In concluding the plant instrumentation part some new monitoring systems and analysis methods are presented: early failure detection methods by noise analysis, acoustic monitoring and vibration monitoring. The presentation of the control starts from an qualitative assessment of the reactor dynamics. The chosen control strategy leads to the definition of the part-load diagram, which provides the set-points for the different control systems. The tasks and the functions of these control systems are described. In additiion to the control, a number of limiting systems is employed to keep the reactor in a safe operating region. Finally, an outlook is given on future developments in control, concerning mainly the increased application of process computers. (orig./RW)

  16. Instrumental analysis, second edition

    International Nuclear Information System (INIS)

    Christian, G.D.; O'Reilly, J.E.

    1988-01-01

    The second edition of Instrumental Analysis is a survey of the major instrument-based methods of chemical analysis. It appears to be aimed at undergraduates but would be equally useful in a graduate course. The volume explores all of the classical quantitative methods and contains sections on techniques that usually are not included in a semester course in instrumentation (such as electron spectroscopy and the kinetic methods). Adequate coverage of all of the methods contained in this book would require several semesters of focused study. The 25 chapters were written by different authors, yet the style throughout the book is more uniform than in the earlier edition. With the exception of a two-chapter course in analog and digital circuits, the book purports to de-emphasize instrumentation, focusing more on the theory behind the methods and the application of the methods to analytical problems. However, a detailed analysis of the instruments used in each method is by no means absent. The book has the favor of a user's guide to analysis

  17. Critical magnetic scattering of polarized neutrons on iron

    International Nuclear Information System (INIS)

    Hetzelt, M.

    1975-01-01

    A new spectrometer has been built and tested. The instrument was designed particularly for small angle scattering of polarized neutrons whereby the degree of polarisation of the scattered neutrons can be measured. The use of polarizing neutron pipes as polarizer and analyser allows the performence with a very broad wavelength spectrum (2 A 7 n/cm 2 sec) with good collimation (Δ theta approximately 0.2 0 ). The instrument is applied for the measurement of the critical magnetic scattering of polarized neutrons on an iron single crystal. For this purpose a special oven with an appropriate magnetic field configuration and a high precision in temperature has been constructed. The measured intensity distributions are in good agreement with other experiments. The critical exponent of the correlation range xi results in 0.65 +- 0.06. Angle and temperature dependence of the scattered neutron polarisation could be determined with good precision. The measurements are partly in extreme contradiction to the only hitherto existing experiment of this kind of Drabkin et al, and to assumptions in the theoretical evaluation. This contradiction is shown to be caused by the influence of multiple scattering. (orig./HPOE) [de

  18. Biochemistry Instrumentation Core Technology Center

    Data.gov (United States)

    Federal Laboratory Consortium — The UCLA-DOE Biochemistry Instrumentation Core Facility provides the UCLA biochemistry community with easy access to sophisticated instrumentation for a wide variety...

  19. Heat Flux Instrumentation Laboratory (HFIL)

    Data.gov (United States)

    Federal Laboratory Consortium — Description: The Heat Flux Instrumentation Laboratory is used to develop advanced, flexible, thin film gauge instrumentation for the Air Force Research Laboratory....

  20. Climate Drives Polar Bear Origins

    Science.gov (United States)

    In their provocative analysis of northern bears (“Nuclear genomic sequences reveal that polar bears are an old and distinct bear lineage,” Reports, 20 April, p. 344), F. Hailer et al. use independent nuclear loci to show that polar bears originated during the middle Pleistocene, rather than during t...

  1. Study of Jupiter polarization properties

    International Nuclear Information System (INIS)

    Bolkvadze, O.R.

    1980-01-01

    Investigations into polarization properties of the Jupiter reflected light were carried on at the Abastumani astrophysical observatory in 1967, 1968 and 1969 in the four spectral ranges: 4000, 4800, 5400 and 6600 A deg. Data on light polarization in different parts of the Jupiter visible disk are given. Curves of dependence of the planet light polarization degree on a phase angle are plotted. It is shown that in the central part of the visible planet disk the polarization degree is low. Atmosphere is in a stable state in this part of Jupiter. Mean radius of particles of a cloud layer is equal to 0.26μ, and optical thickness of overcloud atmosphere tau=0.05. Height of transition boundary of the cloud layer into overcloud gas atmosphere changes from year to year at the edges of the equatorial zone. Optical thickness of overcloud atmosphere changes also with changing height of a transient layer. The polar Jupiter regions possess a high degree of polarization which depends on a latitude. Polarization increases monotonously with the latitude and over polar regions accepts a maximum value [ru

  2. ARGONNE/ NOVOSIBIRSK: Storing polarized deuterons

    International Nuclear Information System (INIS)

    Anon.

    1990-01-01

    Promising new results come from a collaboration between the Institute of Physics, Novosibirsk, and the US Argonne Laboratory, initiated in 1988 to look at the possibilities for using polarized (spin oriented) gas targets in high current electron storage rings, the object being to maximize target polarization levels

  3. The SLAC polarized electron source

    International Nuclear Information System (INIS)

    Clendenin, J.E.; Alley, R.; Frisch, J.; Kotseroglou, T.; Mulhollan, G.; Schultz, D.; Tang, H.; Turner, J.; Yeremian, A.D.

    1997-08-01

    Since 1992, the SLAC 3-km linac has operated exclusively with polarized electrons. The polarized electron source is highly reliable, remotely operated and monitored, and able to produce a variety of electron bunch profiles for high-energy physics experiments. The source and its operating characteristics are described. Some implications drawn from the operating experience are discussed

  4. UV Coatings, Polarization, and Coronagraphy

    Science.gov (United States)

    Bolcar, Matthew R.; Quijada, Manuel; West, Garrett; Balasubramanian, Bala; Krist, John; Martin, Stefan; Sabatke, Derek

    2016-01-01

    Presenation for the Large UltraViolet Optical Infrared (LUVOIR) and Habitable Exoplanet Imager (HabEx) Science and Technology Definition Teams (STDT) on technical considerations regarding ultraviolet coatings, polarization, and coronagraphy. The presentations review the state-of-the-art in ultraviolet coatings, how those coatings generate polarization aberrations, and recent study results from both the LUVOIR and HabEx teams.

  5. Carbon nanotube fiber terahertz polarizer

    Energy Technology Data Exchange (ETDEWEB)

    Zubair, Ahmed [Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005 (United States); Tsentalovich, Dmitri E.; Young, Colin C. [Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005 (United States); Heimbeck, Martin S. [Charles M. Bowden Laboratory, Aviation & Missile Research, Development, and Engineering Center (AMRDEC), Redstone Arsenal, Alabama 35898 (United States); Everitt, Henry O. [Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005 (United States); Charles M. Bowden Laboratory, Aviation & Missile Research, Development, and Engineering Center (AMRDEC), Redstone Arsenal, Alabama 35898 (United States); Pasquali, Matteo [Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005 (United States); Department of Chemistry, Rice University, Houston, Texas 77005 (United States); Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005 (United States); Kono, Junichiro, E-mail: kono@rice.edu [Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005 (United States); Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005 (United States); Department of Physics and Astronomy, Rice University, Houston, Texas 77005 (United States)

    2016-04-04

    Conventional, commercially available terahertz (THz) polarizers are made of uniformly and precisely spaced metallic wires. They are fragile and expensive, with performance characteristics highly reliant on wire diameters and spacings. Here, we report a simple and highly error-tolerant method for fabricating a freestanding THz polarizer with nearly ideal performance, reliant on the intrinsically one-dimensional character of conduction electrons in well-aligned carbon nanotubes (CNTs). The polarizer was constructed on a mechanical frame over which we manually wound acid-doped CNT fibers with ultrahigh electrical conductivity. We demonstrated that the polarizer has an extinction ratio of ∼−30 dB with a low insertion loss (<0.5 dB) throughout a frequency range of 0.2–1.1 THz. In addition, we used a THz ellipsometer to measure the Müller matrix of the CNT-fiber polarizer and found comparable attenuation to a commercial metallic wire-grid polarizer. Furthermore, based on the classical theory of light transmission through an array of metallic wires, we demonstrated the most striking difference between the CNT-fiber and metallic wire-grid polarizers: the latter fails to work in the zero-spacing limit, where it acts as a simple mirror, while the former continues to work as an excellent polarizer even in that limit due to the one-dimensional conductivity of individual CNTs.

  6. Geomorphology of Triton's polar materials

    Science.gov (United States)

    Croft, Steven K.

    1993-01-01

    One of Triton's most debated puzzles is the nature, distribution, and transport of its atmospheric volatiles. The full potential of constraints provided by detailed observations of the morphology and distribution of the polar deposits has not been realized. The objective of this study is characterization of the morphology, distribution, stratigraphy, and geologic setting of Triton's polar materials.

  7. Characteristics of protective instrumentation

    International Nuclear Information System (INIS)

    Reichart, G.

    1982-01-01

    Protective Instrumentation (PI) for Nuclear Power Plants (NPP) is a general term for an highly reliable instrumentation, which provides information for keeping the system within safe limits, for initation of countermeasures in the case of an incident or for mitigation of consequences of an accident. In German NPPs one can find a hierarchical structure of protective instrumentation, wherein the Reactor Protection System (RPS) has the highest priority. To meet the reliability requirements different design principles are used, like - redundancy - diversity - fail safe - decoupling. The presentation gives an overview about the different design principles and characterizes their reliability aspects. As an example for the technical realization the RPS of a German NPP is discussed in some detail. Furthermore some information about other type of PI is given and reliability aspects of the interaction of operating personell with these systems are mentioned. (orig.)

  8. Aethalometer™ Instrument Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Sedlacek, Arthur J. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-04-01

    The Aethalometer is an instrument that provides a real-time readout of the concentration of “Black” or “Elemental” carbon aerosol particles (BC or E) in an air stream (see Figure 1 and Figure 2). It is a self-contained instrument that measures the rate of change of optical transmission through a spot on a filter where aerosol is being continuously collected and uses the information to calculate the concentration of optically absorbing material in the sampled air stream. The instrument measures the transmitted light intensities through the “sensing” portion of the filter, on which the aerosol spot is being collected, and a “reference” portion of the filter as a check on the stability of the optical source. A mass flowmeter monitors the sample air flow rate. The data from these three measurements is used to determine the mean BC content of the air stream.

  9. The IKARUS instrument

    International Nuclear Information System (INIS)

    Gerster, H.J.; Stein, G.

    1994-01-01

    When the Federal Government decided on a 25% reduction of CO 2 emissions till 2005 in 1990 the necessity resulted that an instrument has to be developed for the analysis and assessment of the ecological, economic and energetic impact of different reduction strategies. The development task was awarded by the BMFT to the Research Centre Juelich in cooperation with well-known institutions of energy system research. The total instrument is scheduled to be finished by the end of 1994. For the decentral use of the instrument by a wide specialist public the developed models and data banks which are equipped with a user-friendly surface are suited for larger PCs (486, 16 MB RAM/500-1000 MB ROM). (orig.) [de

  10. ISSUERS OF FINANCIAL INSTRUMENTS

    Directory of Open Access Journals (Sweden)

    Cristian GHEORGHE

    2016-05-01

    Full Text Available The rules laid down by Romanian Capital Market Law and the regulations put in force for its implementation apply to issuers of financial instruments admitted to trading on the regulated market established in Romania. But the issuers remain companies incorporated under Company Law of 1990. Such dual regulations need increased attention in order to observe the legal status of the issuers/companies and financial instruments/shares. Romanian legislator has chosen to implement in Capital Market Law special rules regarding the administration of the issuers of financial instruments, not only rules regarding admitting and maintaining to a regulated market. Thus issuers are, in Romanian Law perspective, special company that should comply special rule regarding board of administration and general shareholders meeting.

  11. Virtual Sensor Test Instrumentation

    Science.gov (United States)

    Wang, Roy

    2011-01-01

    Virtual Sensor Test Instrumentation is based on the concept of smart sensor technology for testing with intelligence needed to perform sell-diagnosis of health, and to participate in a hierarchy of health determination at sensor, process, and system levels. A virtual sensor test instrumentation consists of five elements: (1) a common sensor interface, (2) microprocessor, (3) wireless interface, (4) signal conditioning and ADC/DAC (analog-to-digital conversion/ digital-to-analog conversion), and (5) onboard EEPROM (electrically erasable programmable read-only memory) for metadata storage and executable software to create powerful, scalable, reconfigurable, and reliable embedded and distributed test instruments. In order to maximize the efficient data conversion through the smart sensor node, plug-and-play functionality is required to interface with traditional sensors to enhance their identity and capabilities for data processing and communications. Virtual sensor test instrumentation can be accessible wirelessly via a Network Capable Application Processor (NCAP) or a Smart Transducer Interlace Module (STIM) that may be managed under real-time rule engines for mission-critical applications. The transducer senses the physical quantity being measured and converts it into an electrical signal. The signal is fed to an A/D converter, and is ready for use by the processor to execute functional transformation based on the sensor characteristics stored in a Transducer Electronic Data Sheet (TEDS). Virtual sensor test instrumentation is built upon an open-system architecture with standardized protocol modules/stacks to interface with industry standards and commonly used software. One major benefit for deploying the virtual sensor test instrumentation is the ability, through a plug-and-play common interface, to convert raw sensor data in either analog or digital form, to an IEEE 1451 standard-based smart sensor, which has instructions to program sensors for a wide variety of

  12. Dynamic polarization of radioactive nuclei

    International Nuclear Information System (INIS)

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

    2001-01-01

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

  13. Generalized Expression for Polarization Density

    International Nuclear Information System (INIS)

    Wang, Lu; Hahm, T.S.

    2009-01-01

    A general polarization density which consists of classical and neoclassical parts is systematically derived via modern gyrokinetics and bounce-kinetics by employing a phase-space Lagrangian Lie-transform perturbation method. The origins of polarization density are further elucidated. Extending the work on neoclassical polarization for long wavelength compared to ion banana width [M. N. Rosenbluth and F. L. Hinton, Phys. Rev. Lett. 80, 724 (1998)], an analytical formula for the generalized neoclassical polarization including both finite-banana-width (FBW) and finite-Larmor-radius (FLR) effects for arbitrary radial wavelength in comparison to banana width and gyroradius is derived. In additional to the contribution from trapped particles, the contribution of passing particles to the neoclassical polarization is also explicitly calculated. Our analytic expression agrees very well with the previous numerical results for a wide range of radial wavelength.

  14. Measuring the sea quark polarization

    International Nuclear Information System (INIS)

    Makdisi, Y.

    1993-01-01

    Spin is a fundamental degree of freedom and measuring the spin structure functions of the nucleon should be a basic endeavor for hadron physics. Polarization experiments have been the domain of fixed target experiments. Over the years large transverse asymmetries have been observed where the prevailing QCD theories predicted little or no asymmetries, and conversely the latest deep inelastic scattering experiments of polarized leptons from polarized targets point to the possibility that little of the nucleon spin is carried by the valence quarks. The possibility of colliding high luminosity polarized proton beams in the Brookhaven Relativistic Heavy Ion Collider (RHIC) provides a great opportunity to extend these studies and systematically probe the spin dependent parton distributions specially to those reactions that are inaccessible to current experiments. This presentation focuses on the measurement of sea quark and possibly the strange quark polarization utilizing the approved RHIC detectors

  15. A review of polarized ion sources

    International Nuclear Information System (INIS)

    Schmor, P.W.

    1995-06-01

    The two main types of polarized ion sources in use on accelerators today are the Atomic Beam Polarized Ion Source (ABIS) source and the Optically Pumped Polarized Ion Source (OPPIS). Both types can provide beams of nuclearly polarized light ions which are either positively or negatively charged. Heavy ion polarized ion sources for accelerators are being developed. (author). 35 refs., 1 tab

  16. Polarization phenomena in heavy-ion reactions

    International Nuclear Information System (INIS)

    Sugimoto, K.; Ishihara, M.; Takahashi, N.

    1984-01-01

    This chapter presents a few key experiments which provide direct evidence of the polarization phenomena in heavy-ion reactions. The theory of polarization observables and measurements is given with the necessary formulae. The polarization phenomena is described and studies of product nuclear polarization in heavy-ion reactions are discussed. Studies of heavy-ion reactions induced by polarized beams are examined

  17. ICFA: Instrumentation school

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1987-10-15

    74 students, including 45 from developing countries, ten lecturers and nine laboratory instructors participated in the novel instrumentation school held in June at the International Centre for Theoretical Physics (ICTP), Trieste, Italy, sponsored by ICTP and arranged through the Instrumentation Panel of the International Committee for Future Accelerators (ICF). During the two weeks of the course, students had the chance to construct and test a proportional chamber, measure the lifetime of cosmic ray muons, operate and analyse the performance of an 8-wire imaging drift chamber, or study noise and signal processing using a silicon photodiode.

  18. Interfacing to accelerator instrumentation

    International Nuclear Information System (INIS)

    Shea, T.J.

    1995-01-01

    As the sensory system for an accelerator, the beam instrumentation provides a tremendous amount of diagnostic information. Access to this information can vary from periodic spot checks by operators to high bandwidth data acquisition during studies. In this paper, example applications will illustrate the requirements on interfaces between the control system and the instrumentation hardware. A survey of the major accelerator facilities will identify the most popular interface standards. The impact of developments such as isochronous protocols and embedded digital signal processing will also be discussed

  19. Spectroelectrochemical Instrument Measures TOC

    Science.gov (United States)

    Kounaves, Sam

    2011-01-01

    A spectroelectrochemical instrument has been developed for measuring the total organic carbon (TOC) content of an aqueous solution. Measurements of TOC are frequently performed in environmental, clinical, and industrial settings. Until now, techniques for performing such measurements have included, various ly, the use of hazardous reagents, ultraviolet light, or ovens, to promote reactions in which the carbon contents are oxidized. The instrument now being developed is intended to be a safer, more economical means of oxidizing organic carbon and determining the TOC levels of aqueous solutions and for providing a low power/mass unit for use in planetary missions.

  20. Neutron multiplication measurement instrument

    International Nuclear Information System (INIS)

    Nixon, K.V.; Dowdy, E.J.; France, S.W.; Millegan, D.R.; Robba, A.A.

    1983-01-01

    The Advanced Nuclear Technology Group of the Los Alamos National Laboratory is now using intelligent data-acquisition and analysis instrumentation for determining the multiplication of nuclear material. Earlier instrumentation, such as the large NIM-crate systems, depended on house power and required additional computation to determine multiplication or to estimate error. The portable, battery-powered multiplication measurement unit, with advanced computational power, acquires data, calculates multiplication, and completes error analysis automatically. Thus, the multiplication is determined easily and an available error estimate enables the user to judge the significance of results

  1. Standard NIM instrumentation system

    International Nuclear Information System (INIS)

    1990-05-01

    NIM is a standard modular instrumentation system that is in wide use throughout the world. As the NIM system developed and accommodations were made to a dynamic instrumentation field and a rapidly advancing technology, additions, revisions and clarifications were made. These were incorporated into the standard in the form of addenda and errata. This standard is a revision of the NIM document, AEC Report TID-20893 (Rev. 4) dated July 1974. It includes all the addenda and errata items that were previously issued as well as numerous additional items to make the standard current with modern technology and manufacturing practice

  2. Virtual Reality Musical Instruments

    DEFF Research Database (Denmark)

    Serafin, Stefania; Erkut, Cumhur; Kojs, Juraj

    2016-01-01

    The rapid development and availability of low-cost technologies have created a wide interest in virtual reality. In the field of computer music, the term “virtual musical instruments” has been used for a long time to describe software simulations, extensions of existing musical instruments......, and ways to control them with new interfaces for musical expression. Virtual reality musical instruments (VRMIs) that include a simulated visual component delivered via a head-mounted display or other forms of immersive visualization have not yet received much attention. In this article, we present a field...

  3. ICFA: Instrumentation school

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    74 students, including 45 from developing countries, ten lecturers and nine laboratory instructors participated in the novel instrumentation school held in June at the International Centre for Theoretical Physics (ICTP), Trieste, Italy, sponsored by ICTP and arranged through the Instrumentation Panel of the International Committee for Future Accelerators (ICF). During the two weeks of the course, students had the chance to construct and test a proportional chamber, measure the lifetime of cosmic ray muons, operate and analyse the performance of an 8-wire imaging drift chamber, or study noise and signal processing using a silicon photodiode

  4. Instrumentation Cables Test Plan

    Energy Technology Data Exchange (ETDEWEB)

    Muna, Alice Baca [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); LaFleur, Chris Bensdotter [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-10-01

    A fire at a nuclear power plant (NPP) has the potential to damage structures, systems, and components important to safety, if not promptly detected and suppressed. At Browns Ferry Nuclear Power Plant on March 22, 1975, a fire in the reactor building damaged electrical power and control systems. Damage to instrumentation cables impeded the function of both normal and standby reactor coolant systems, and degraded the operators’ plant monitoring capability. This event resulted in additional NRC involvement with utilities to ensure that NPPs are properly protected from fire as intended by the NRC principle design criteria (i.e., general design criteria 3, Fire Protection). Current guidance and methods for both deterministic and performance based approaches typically make conservative (bounding) assumptions regarding the fire-induced failure modes of instrumentation cables and those failure modes effects on component and system response. Numerous fire testing programs have been conducted in the past to evaluate the failure modes and effects of electrical cables exposed to severe thermal conditions. However, that testing has primarily focused on control circuits with only a limited number of tests performed on instrumentation circuits. In 2001, the Nuclear Energy Institute (NEI) and the Electric Power Research Institute (EPRI) conducted a series of cable fire tests designed to address specific aspects of the cable failure and circuit fault issues of concern1. The NRC was invited to observe and participate in that program. The NRC sponsored Sandia National Laboratories to support this participation, whom among other things, added a 4-20 mA instrumentation circuit and instrumentation cabling to six of the tests. Although limited, one insight drawn from those instrumentation circuits tests was that the failure characteristics appeared to depend on the cable insulation material. The results showed that for thermoset insulated cables, the instrument reading tended to drift

  5. Celadon Figurines Play Instruments

    Institute of Scientific and Technical Information of China (English)

    1995-01-01

    This group of figurines, each 0.15m tall, were unearthed from a Tang Dynasty tomb in Changsha in 1977. Music was very developed in the Tang Dynasty. Colorful musical instruments and dances were popular both among the people and in the palace. These vivid-looking figurines wear pleated skirts with small sleeves and open chest, a style influenced by the non-Han nationalities living in the north and west of China. Some of the musical instruments were brought from the Western Regions. The figurines are playing the xiao (a vertical bamboo flute), the konghou (an

  6. SOUTH POL: Revealing the Polarized Southern Sky

    Science.gov (United States)

    Magalhaes, Antonio Mario Mario; Ramírez, Edgar; Ribeiro, Nadili; Seriacopi, Daiane; Rubinho, Marcelo; Ferrari, Tiberio; Rodrigues, Claudia; Schoenell, William; Herpich, Fabio; Pereyra, Antonio

    2018-01-01

    SOUTH POL will be a survey of the Southern sky in optical polarized light. It will use a newly built polarimeter for T80-S, an 84 cm robotic telescope installed at Cerro Tololo (CTIO), Chile. It will initially cover the sky South of declination -15 deg with a polarimetric accuracy Solar System.The polarimeter has just been commissioned in mid-November, 2017. The data reduction pipeline has already been built. We will describe the instrument and the data reduction, as well as a few of the science cases. The survey is expected to begin midway through the 1st semester of 2018. Both catalog data and raw images will be made available.

  7. Physics with polarized electron beams

    International Nuclear Information System (INIS)

    Swartz, M.L.

    1988-01-01

    As a distinct field, elementary particle physics is now approximately forty years old. In all that time, only a few of the thousands of experiments that have been performed have made use of spin polarized particle beams (with apologies to those who have studied neutrino interactions, polarized beam are defined to refer to the case in which the experimenter has control over the polarization direction). If the discussion is restricted to spin polarized electron beams, the number of experiments becomes countable with the fingers of one hand (with several to spare). There are two reasons for this lack of interest. The first is that spin polarized beams are difficult to produce, accelerate, and transport. The second reason is that any physical process that can occur during the collision of a polarized particle with another (polarized or not) can also occur during the collision of unpolarized particles. One might ask then, why has any effort been expended on the subject. The answer, at least in the case of polarized electron beams, is that electron accelerators and storage rings have in recent years achieved sufficient energy to begin to probe the weak interaction directly. The weak interaction distinguishes between left- and right-handed fermionic currents. Left-handed particles interact in a fundamentally different way than their right-handed counterparts. If the experimenter wishes to explore or exploit this difference, he (or she) must either prepare the spin state of the incident particles or analyze the spin state of outgoing particles. For reasons of genearlity and improved statistical precision, the former is usually preferable to the latter. The first of these lectures will review some of the techniques necessary for the production, transport, and monitoring of polarized electron (or positron) beams. The second lecture will survey some of the physics possibilities of polarized electron-positron collisions

  8. Promoting Diversity Through Polar Interdisciplinary Coordinated Education (Polar ICE)

    Science.gov (United States)

    McDonnell, J. D.; Hotaling, L. A.; Garza, C.; Van Dyk, P. B.; Hunter-thomson, K. I.; Middendorf, J.; Daniel, A.; Matsumoto, G. I.; Schofield, O.

    2017-12-01

    Polar Interdisciplinary Coordinated Education (ICE) is an education and outreach program designed to provide public access to the Antarctic and Arctic regions through polar data and interactions with the scientists. The program provides multi-faceted science communication training for early career scientists that consist of a face-to face workshop and opportunities to apply these skills. The key components of the scientist training workshop include cultural competency training, deconstructing/decoding science for non-expert audiences, the art of telling science stories, and networking with members of the education and outreach community and reflecting on communication skills. Scientists partner with educators to provide professional development for K-12 educators and support for student research symposia. Polar ICE has initiated a Polar Literacy initiative that provides both a grounding in big ideas in polar science and science communication training designed to underscore the importance of the Polar Regions to the public while promoting interdisciplinary collaborations between scientists and educators. Our ultimate objective is to promote STEM identity through professional development of scientists and educators while developing career awareness of STEM pathways in Polar science.

  9. Inspector-instrument interface in portable NDA instrumentation

    International Nuclear Information System (INIS)

    Halbig, J.K.; Klosterbuer, S.F.

    1981-01-01

    Recent electronics technology advances make it possible to design sophisticated instruments in small packages for convenient field implementation. An inspector-instrument interface design that allows communication of procedures, responses, and results between the instrument and user is presented. This capability has been incorporated into new spent-fuel instrumentation and a battery-powered multichannel analyzer

  10. Inspector-instrument interface in portable NDA instrumentation

    International Nuclear Information System (INIS)

    Halbig, J.K.; Klosterbuer, S.F.

    1981-01-01

    Recent electronics technology advances make it possible to design sophisticated instruments in small packages for convenient field implementation. This report describes an inspector-instrument interface design which allows communication of procedures, responses, and results between the instrument and user. The interface has been incorporated into new spent-fuel instrumentation and a battery-powered multichannel analyzer

  11. Lunar true polar wander inferred from polar hydrogen.

    Science.gov (United States)

    Siegler, M A; Miller, R S; Keane, J T; Laneuville, M; Paige, D A; Matsuyama, I; Lawrence, D J; Crotts, A; Poston, M J

    2016-03-24

    The earliest dynamic and thermal history of the Moon is not well understood. The hydrogen content of deposits near the lunar poles may yield insight into this history, because these deposits (which are probably composed of water ice) survive only if they remain in permanent shadow. If the orientation of the Moon has changed, then the locations of the shadowed regions will also have changed. The polar hydrogen deposits have been mapped by orbiting neutron spectrometers, and their observed spatial distribution does not match the expected distribution of water ice inferred from present-day lunar temperatures. This finding is in contrast to the distribution of volatiles observed in similar thermal environments at Mercury's poles. Here we show that polar hydrogen preserves evidence that the spin axis of the Moon has shifted: the hydrogen deposits are antipodal and displaced equally from each pole along opposite longitudes. From the direction and magnitude of the inferred reorientation, and from analysis of the moments of inertia of the Moon, we hypothesize that this change in the spin axis, known as true polar wander, was caused by a low-density thermal anomaly beneath the Procellarum region. Radiogenic heating within this region resulted in the bulk of lunar mare volcanism and altered the density structure of the Moon, changing its moments of inertia. This resulted in true polar wander consistent with the observed remnant polar hydrogen. This thermal anomaly still exists and, in part, controls the current orientation of the Moon. The Procellarum region was most geologically active early in lunar history, which implies that polar wander initiated billions of years ago and that a large portion of the measured polar hydrogen is ancient, recording early delivery of water to the inner Solar System. Our hypothesis provides an explanation for the antipodal distribution of lunar polar hydrogen, and connects polar volatiles to the geologic and geophysical evolution of the Moon

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

    Science.gov (United States)

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

    2018-06-01

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

  13. POLARIZED BEAMS: 1 - Longitudinal electron spin polarization at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1994-09-15

    Wednesday 4 May marked a turning point in the art of the manipulation of spins in electron storage rings: longitudinal electron spin polarization (with the spins oriented along the electrons' direction of motion) was established in the electron ring of HERA, the electronproton collider at DESY in Hamburg. A polarization level of about 55% was obtained and polarizations of over 60% were reproducibly obtained in the following days. The beam energy was 27.52 GeV, corresponding to half integer spin tune of 62.5.

  14. Sustaining observations in the polar oceans.

    Science.gov (United States)

    Abrahamsen, E P

    2014-09-28

    Polar oceans present a unique set of challenges to sustained observations. Sea ice cover restricts navigation for ships and autonomous measurement platforms alike, and icebergs present a hazard to instruments deployed in the upper ocean and in shelf seas. However, the important role of the poles in the global ocean circulation provides ample justification for sustained observations in these regions, both to monitor the rapid changes taking place, and to better understand climate processes in these traditionally poorly sampled areas. In the past, the vast majority of polar measurements took place in the summer. In recent years, novel techniques such as miniature CTD (conductivity-temperature-depth) tags carried by seals have provided an explosion in year-round measurements in areas largely inaccessible to ships, and, as ice avoidance is added to autonomous profiling floats and gliders, these promise to provide further enhancements to observing systems. In addition, remote sensing provides vital information about changes taking place in sea ice cover at both poles. To make these observations sustainable into the future, improved international coordination and collaboration is necessary to gain optimum utilization of observing networks. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  15. Polarized neutron reflectometry on thin magnetic films

    International Nuclear Information System (INIS)

    Van Der Graaf, A.

    1997-01-01

    In order to be sensitive to magnetic scattering with X-rays very high intensities have to be used. This makes it necessary to use large installations like synchroton radiation sources providing high X-ray intensities. Polarized neutron experiments can be performed even at small reactors like the 2 MW reactor of IRI. In general polarized neutron reflectometry (PNR) is used to determine magnetization depth profiles, whereas X-ray reflectometry is used to study magnetic surfaces. Chapters 2 through 4 of this thesis are general chapters. The theory of neutron reflectometry is described in chapter 2, followed by a description of the ROG instrument (a time-of-flight reflectometer) in chapter 3, and chapter 4 deals with the data analysis. In the subsequent chapters PNR-experiments on different kinds of samples are discussed. First, experiments on a Co-Cr layer, a candidate to be used as perpendicular recording medium, are described in chapter 5. In chapter 6 it is shown that PNR can give information on metal evaporated videotapes, as presently available in every ordinary shop selling videotapes, and also on the writing process in these tapes. Chapter 7 deals with experiments on Fe/Si multilayers. The initial interest in such multilayers was to obtain information on magnetic coupling through a semiconductor. In chapter 8 PNR-experiments on spin-valve systems, that probably will be used as magnetic read head material, are described. Finally, chapter 9 gives some conclusions and recommendations for the future. 78 refs

  16. UAVSAR Program: Initial Results from New Instrument Capabilities

    Science.gov (United States)

    Lou, Yunling; Hensley, Scott; Moghaddam, Mahta; Moller, Delwyn; Chapin, Elaine; Chau, Alexandra; Clark, Duane; Hawkins, Brian; Jones, Cathleen; Marks, Phillip; hide

    2013-01-01

    UAVSAR is an imaging radar instrument suite that serves as NASA's airborne facility instrument to acquire scientific data for Principal Investigators as well as a radar test-bed for new radar observation techniques and radar technology demonstration. Since commencing operational science observations in January 2009, the compact, reconfigurable, pod-based radar has been acquiring L-band fully polarimetric SAR (POLSAR) data with repeat-pass interferometric (RPI) observations underneath NASA Dryden's Gulfstream-III jet to provide measurements for science investigations in solid earth and cryospheric studies, vegetation mapping and land use classification, archaeological research, soil moisture mapping, geology and cold land processes. In the past year, we have made significant upgrades to add new instrument capabilities and new platform options to accommodate the increasing demand for UAVSAR to support scientific campaigns to measure subsurface soil moisture, acquire data in the polar regions, and for algorithm development, verification, and cross-calibration with other airborne/spaceborne instruments.

  17. Update of the Polar SWIFT model for polar stratospheric ozone loss (Polar SWIFT version 2)

    Science.gov (United States)

    Wohltmann, Ingo; Lehmann, Ralph; Rex, Markus

    2017-07-01

    The Polar SWIFT model is a fast scheme for calculating the chemistry of stratospheric ozone depletion in polar winter. It is intended for use in global climate models (GCMs) and Earth system models (ESMs) to enable the simulation of mutual interactions between the ozone layer and climate. To date, climate models often use prescribed ozone fields, since a full stratospheric chemistry scheme is computationally very expensive. Polar SWIFT is based on a set of coupled differential equations, which simulate the polar vortex-averaged mixing ratios of the key species involved in polar ozone depletion on a given vertical level. These species are O3, chemically active chlorine (ClOx), HCl, ClONO2 and HNO3. The only external input parameters that drive the model are the fraction of the polar vortex in sunlight and the fraction of the polar vortex below the temperatures necessary for the formation of polar stratospheric clouds. Here, we present an update of the Polar SWIFT model introducing several improvements over the original model formulation. In particular, the model is now trained on vortex-averaged reaction rates of the ATLAS Chemistry and Transport Model, which enables a detailed look at individual processes and an independent validation of the different parameterizations contained in the differential equations. The training of the original Polar SWIFT model was based on fitting complete model runs to satellite observations and did not allow for this. A revised formulation of the system of differential equations is developed, which closely fits vortex-averaged reaction rates from ATLAS that represent the main chemical processes influencing ozone. In addition, a parameterization for the HNO3 change by denitrification is included. The rates of change of the concentrations of the chemical species of the Polar SWIFT model are purely chemical rates of change in the new version, whereas in the original Polar SWIFT model, they included a transport effect caused by the

  18. Power station instrumentation

    International Nuclear Information System (INIS)

    Jervis, M.W.

    1993-01-01

    Power stations are characterized by a wide variety of mechanical and electrical plant operating with structures, liquids and gases working at high pressures and temperatures and with large mass flows. The voltages and currents are also the highest that occur in most industries. In order to achieve maximum economy, the plant is operated with relatively small margins from conditions that can cause rapid plant damage, safety implications, and very high financial penalties. In common with other process industries, power stations depend heavily on control and instrumentation. These systems have become particularly significant, in the cost-conscious privatized environment, for providing the means to implement the automation implicit in maintaining safety standards, improving generation efficiency and reducing operating manpower costs. This book is for professional instrumentation engineers who need to known about their use in power stations and power station engineers requiring information about the principles and choice of instrumentation available. There are 8 chapters; chapter 4 on instrumentation for nuclear steam supply systems is indexed separately. (Author)

  19. University Reactor Instrumentation Program

    International Nuclear Information System (INIS)

    Vernetson, W.G.

    1992-11-01

    Recognizing that the University Reactor Instrumentation Program was developed in response to widespread needs in the academic community for modernization and improvement of research and training reactors at institutions such as the University of Florida, the items proposed to be supported by this grant over its two year period have been selected as those most likely to reduce foreed outages, to meet regulatory concerns that had been expressed in recent years by Nuclear Regulatory Commission inspectors or to correct other facility problems and limitations. Department of Energy Grant Number DE-FG07-90ER129969 was provided to the University of Florida Training Reactor(UFTR) facility through the US Department of Energy's University Reactor Instrumentation Program. The original proposal submitted in February, 1990 requested support for UFTR facility instrumentation and equipment upgrades for seven items in the amount of $107,530 with $13,800 of this amount to be the subject of cost sharing by the University of Florida and $93,730 requested as support from the Department of Energy. A breakdown of the items requested and total cost for the proposed UFTR facility instrumentation and equipment improvements is presented

  20. Neutron instrumentation for biology

    Energy Technology Data Exchange (ETDEWEB)

    Mason, S.A. [Institut Laue-Langevin, Grenoble (France)

    1994-12-31

    In the October 1994 round of proposals at the ILL, the external biology review sub- committee was asked to allocate neutron beam time to a wide range of experiments, on almost half the total number of scheduled neutron instruments: on 3 diffractometers, on 3 small angle scattering instruments, and on some 6 inelastic scattering spectrometers. In the 3.5 years since the temporary reactor shutdown, the ILL`s management structure has been optimized, budgets and staff have been trimmed, the ILL reactor has been re-built, and many of the instruments up-graded, many powerful (mainly Unix) workstations have been introduced, and the neighboring European Synchrotron Radiation Facility has established itself as the leading synchrotron radiation source and has started its official user program. The ILL reactor remains the world`s most intense dedicated neutron source. In this challenging context, it is of interest to review briefly the park of ILL instruments used to study the structure and energetics of small and large biological systems. A brief summary will be made of each class of experiments actually proposed in the latest ILL proposal round.

  1. The ozone monitoring instrument

    NARCIS (Netherlands)

    Levelt, P.F.; Oord, G.H.J. van den; Dobber, M.R.; Mälkki, A.; Visser, H.; Vries, J. de; Stammes, P.; Lundell, J.O.V.; Saari, H.

    2006-01-01

    The Ozone Monitoring Instrument (OMI) flies on the National Aeronautics and Space Adminsitration's Earth Observing System Aura satellite launched in July 2004. OMI is a ultraviolet/visible (UV/VIS) nadir solar backscatter spectrometer, which provides nearly global coverage in one day with a spatial

  2. Economic Policy Instruments

    DEFF Research Database (Denmark)

    Klemmensen, Børge

    2007-01-01

    Økonomiske instrumenter begrundes med behovet for politiske indgreb, der muliggør internaliseringen af omkostningerne ved de miljøpåvirkninger, produktion and levevis afstedkommer, således at hensyntagen til miljøet bliver en del af virksomheders og husholdningers omkostninger og dermed en tilsky...

  3. Radiometric well logging instruments

    International Nuclear Information System (INIS)

    Davydov, A.V.

    1975-01-01

    The technical properties of well instruments for radioactive logging used in the radiometric logging complexes PKS-1000-1 (''Sond-1'') and PRKS-2 (''Vitok-2'') are described. The main features of the electric circuit of the measuring channels are given

  4. Advanced instrumentation and teleoperation

    International Nuclear Information System (INIS)

    Decreton, M.

    1998-01-01

    SCK-CEN's advanced instrumentation and teleoperation project aims at evaluating the potential of a telerobotic approach in a nuclear environment and, in particular, the use of remote-perception systems. Main achievements in 1997 in the areas of R and D on radiation tolerance for remote sensing, optical fibres and optical-fibre sensors, and computer-aided teleoperation are reported

  5. Health physics instrumentation needs

    International Nuclear Information System (INIS)

    Selby, J.M.; Swinth, K.L.; Kenoyer, J.L.

    1984-10-01

    Deficiencies and desirable improvements can be identified in every technical area in which health physics instruments are employed. The needed improvements cover the full spectrum including long-term reliability, human factors, accuracy, ruggedness, ease of calibration, improved radiation response, and improved mixed field response. Some specific areas of deficiency noted along with needed improvements. 17 references

  6. Virtual reality musical instruments

    DEFF Research Database (Denmark)

    Serafin, Stefania; Erkut, Cumhur; Kojs, Juraj

    2016-01-01

    The rapid development and availability of low cost technologies has created a wide interest in virtual reality (VR), but how to design and evaluate multisensory interactions in VR remains as a challenge. In this paper, we focus on virtual reality musical instruments, present an overview of our...

  7. Creating a Super Instrument

    DEFF Research Database (Denmark)

    Kallionpää, Maria; Gasselseder, Hans-Peter

    2015-01-01

    Thanks to the development of new technology, musical instruments are no more tied to their existing acoustic or technical limitations as almost all parameters can be augmented or modified in real time. An increasing number of composers, performers, and computer programmers have thus become intere...

  8. CMO Site: Ocean Instrumentation

    Science.gov (United States)

    1997-02-01

    Precipitation , Lightning, Visibility 0150 A InterOcea Hawser Strain 1.. systems, inc. and more... n 1946 3540 aero court san diego ca 92123-1799 usa phone: (619...AGU’s Microgal culture Association, P.O. Box 1004, April 8-10, 1997-Underwater Gravimetry : Instruments, Observa- Niland, CA 92257; (619) 359-3474

  9. Instrumentation in thermoluminescence dosimetry

    International Nuclear Information System (INIS)

    Julius, H.W.

    1986-01-01

    In the performance of a thermoluminescence dosimetry (TLD) system the equipment plays an important role. Crucial parameters of instrumentation in TLD are discussed in some detail. A review is given of equipment available on the market today - with some emphasis on automation - which is partly based on information from industry and others involved in research and development. (author)

  10. Ion chamber instrument

    International Nuclear Information System (INIS)

    Stephan, D.H.

    1975-01-01

    An electrical ionization chamber is described having a self-supporting wall of cellular material which is of uniform areal density and formed of material, such as foamed polystyrene, having an average effective atomic number between about 4 and about 9, and easily replaceable when on the instrument. (auth)

  11. Integrating Nephelometer Instrument Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Uin, J. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-03-01

    The Integrating Nephelometer (Figure 1) is an instrument that measures aerosol light scattering. It measures aerosol optical scattering properties by detecting (with a wide angular integration – from 7 to 170°) the light scattered by the aerosol and subtracting the light scattered by the carrier gas, the instrument walls and the background noise in the detector (zeroing). Zeroing is typically performed for 5 minutes every day at midnight UTC. The scattered light is split into red (700 nm), green (550 nm), and blue (450 nm) wavelengths and captured by three photomultiplier tubes. The instrument can measure total scatter as well as backscatter only (from 90 to 170°) (Heintzenberg and Charlson 1996; Anderson et al. 1996; Anderson and Ogren 1998; TSI 3563 2015) At ARM (Atmospheric Radiation Measurement), two identical Nephelometers are usually run in series with a sample relative humidity (RH) conditioner between them. This is possible because Nephelometer sampling is non-destructive and the sample can be passed on to another instrument. The sample RH conditioner scans through multiple RH values in cycles, treating the sample. This kind of setup allows to study how aerosol particles’ light scattering properties are affected by humidification (Anderson et al. 1996). For historical reasons, the two Nephelometers in this setup are labeled “wet” and “dry”, with the “dry” Nephelometer usually being the one before the conditioner and sampling ambient air (the names are switched for the MAOS measurement site due to the high RH of the ambient air).

  12. Measurement and Instrumentation

    Energy Technology Data Exchange (ETDEWEB)

    Kirkham, Harold

    2018-01-02

    This is a chapter for a book called the Standard Handbook for Electrical Engineering. Though it is not obvious from the title, the book deals mainly with power engineering. The first chapter (not mine) is about the fundamental quantities used in measurement. This chapter is about the process and the instrumentation.

  13. Analytical chemistry instrumentation

    International Nuclear Information System (INIS)

    Laing, W.R.

    1986-01-01

    In nine sections, 48 chapters cover 1) analytical chemistry and the environment 2) environmental radiochemistry 3) automated instrumentation 4) advances in analytical mass spectrometry 5) fourier transform spectroscopy 6) analytical chemistry of plutonium 7) nuclear analytical chemistry 8) chemometrics and 9) nuclear fuel technology

  14. CRISP instrument manual

    International Nuclear Information System (INIS)

    Bucknall, D.G.; Langridge, Sean

    1997-05-01

    This document is a user manual for CRISP, one of the two neutron reflectomers at ISIS. CRISP is highly automated allowing precision reproducible measurements. The manual provides detailed instructions for the setting-up and running of the instrument and advice on data analysis. (UK)

  15. Circular polarization of light by planet Mercury and enantiomorphism of its surface minerals.

    Science.gov (United States)

    Meierhenrich, Uwe J; Thiemann, Wolfram H P; Barbier, Bernard; Brack, André; Alcaraz, Christian; Nahon, Laurent; Wolstencroft, Ray

    2002-04-01

    Different mechanisms for the generation of circular polarization by the surface of planets and satellites are described. The observed values for Venus, the Moon, Mars, and Jupiter obtained by photo-polarimetric measurements with Earth based telescopes, showed accordance with theory. However, for planet Mercury asymmetric parameters in the circular polarization were measured that do not fit with calculations. For BepiColombo, the ESA cornerstone mission 5 to Mercury, we propose to investigate this phenomenon using a concept which includes two instruments. The first instrument is a high-resolution optical polarimeter, capable to determine and map the circular polarization by remote scanning of Mercury's surface from the Mercury Planetary Orbiter MPO. The second instrument is an in situ sensor for the detection of the enantiomorphism of surface crystals and minerals, proposed to be included in the Mercury Lander MSE.

  16. Monochromatic Measurements of the JPSS-1 VIIRS Polarization Sensitivity

    Science.gov (United States)

    McIntire, Jeff; Moyer, David; Brown, Steven W.; Lykke, Keith R.; Waluschka, Eugene; Oudrari, Hassan; Xiong, Xiaoxiong

    2016-01-01

    Polarization sensitivity is a critical property that must be characterized for spaceborne remote sensing instruments designed to measure reflected solar radiation. Broadband testing of the first Joint Polar-orbiting Satellite System (JPSS-1) Visible Infrared Imaging Radiometer Suite (VIIRS) showed unexpectedly large polarization sensitivities for the bluest bands on VIIRS (centered between 400 and 600 nm). Subsequent ray trace modeling indicated that large diattenuation on the edges of the bandpass for these spectral bands was the driver behind these large sensitivities. Additional testing using the National Institute of Standards and Technologies Traveling Spectral Irradiance and Radiance Responsivity Calibrations Using Uniform Sources was added to the test program to verify and enhance the model. The testing was limited in scope to two spectral bands at two scan angles; nonetheless, this additional testing provided valuable insight into the polarization sensitivity. Analysis has shown that the derived diattenuation agreed with the broadband measurements to within an absolute difference of about0.4 and that the ray trace model reproduced the general features of the measured data. Additionally, by deriving the spectral responsivity, the linear diattenuation is shown to be explicitly dependent on the changes in bandwidth with polarization state.

  17. Mechanisms of Cell Polarity-Controlled Epithelial Homeostasis and Immunity in the Intestine.

    Science.gov (United States)

    Klunder, Leon J; Faber, Klaas Nico; Dijkstra, Gerard; van IJzendoorn, Sven C D

    2017-07-05

    Intestinal epithelial cell polarity is instrumental to maintain epithelial homeostasis and balance communications between the gut lumen and bodily tissue, thereby controlling the defense against gastrointestinal pathogens and maintenance of immune tolerance to commensal bacteria. In this review, we highlight recent advances with regard to the molecular mechanisms of cell polarity-controlled epithelial homeostasis and immunity in the human intestine. Copyright © 2017 Cold Spring Harbor Laboratory Press; all rights reserved.

  18. Extreme-scale alignments of quasar optical polarizations and Galactic dust contamination

    OpenAIRE

    Pelgrims, Vincent

    2017-01-01

    Almost twenty years ago the optical polarization vectors from quasars were shown to be aligned over extreme-scales. That evidence was later confirmed and enhanced thanks to additional optical data obtained with the ESO instrument FORS2 mounted on the VLT, in Chile. These observations suggest either Galactic foreground contamination of the data or, more interestingly, a cosmological origin. Using 353-GHz polarization data from the Planck satellite, I recently showed that the main features of t...

  19. Applications of circularly polarized photons at the ALS with a bend magnet source

    International Nuclear Information System (INIS)

    1992-02-01

    The purpose of this workshop is to focus attention on, and to stimulate the scientific exploitation of, the natural polarization properties of bend-magnet synchrotron radiation at the ALS -- for research in biology, materials science, physics, and chemistry. The topics include: The Advanced Light Source; Magnetic Circular Dichroism and Differential Scattering on Biomolecules; Tests of Fundamental Symmetries; High T c Superconductivity; Photoemission from Magnetic and Non-magnetic Solids; Studies of Highly Correlated Systems; and Instrumentation for Photon Transport and Polarization Measurements

  20. Inexpensive microwave survey instruments: an evaluation

    International Nuclear Information System (INIS)

    Herman, W.A.; Witters, D.M. Jr.

    1979-11-01

    Instruments were tested. Depending upon the oven modulation and leak location these tests show that the Micromate will yield a warning reading at levels from 0.6 to 1.9 mW/cm 2 , when the effects of modulation sensitivity and polarization ellipticity are considered. It is to be expected, then, that this instrument will yield warning readings even when the oven emission being measured lies well within applicable standards. Its apparent susceptibility to overload damage, however, could decrease its sensitivity with no clue to the user as to what had happened. Given the same considerations and parameters, the tests show that the Guard-Rod will yield a warning reading at levels from 3.7 to 47 mW/cm 2 , depending on which measurement surface is used. This instrument will sometimes yield warnings for oven emissions lying within applicable standards, and sometimes will fail to yield such warnings for emissions 10 times greater than allowable levels. The same considerations show that the Interceptor/Microscan units will light up at levels from as low as 0.7 to 0.8 mW/cm 2 or may require levels of 7 to 9 mW/cm 2 . At levels of 28 to 52 mW/cm 2 or higher, however, the warning LED does not light. If part of the field is cross-polarized, this threshold of extinction may be greater. In any case, there is no apparent way for the user to discern the presence of some potentially hazardous fields, and no way to distinguish such fields from a very low-level field. In summary, instruments of the Interceptor/Microscan design may light up at very low power densities, but fail to light at very high power densities. Clearly, this characteristic is extremely undesirable and potentially dangerous to a user relying on such a device.All of these values assume that the instruments are used in accordance with manufacturer's instructions. Otherwise, results may be worse. Moreover, the range of values given take little or no account of unit-to-unit variation, which may be considerable

  1. Nuclear physics with polarized particles

    CERN Document Server

    Paetz gen Schieck, Hans

    2012-01-01

    The measurement of spin-polarization observables in reactions of nuclei and particles is of great utility and advantage when the effects of single-spin sub-states are to be investigated. Indeed, the unpolarized differential cross-section encompasses the averaging over the spin states of the particles, and thus loses details of the interaction process. This introductory text combines, in a single volume, course-based lecture notes on spin physics and on polarized-ion sources with the aim of providing a concise yet self-contained starting point for newcomers to the field, as well as for lecturers in search of suitable material for their courses and seminars. A significant part of the book is devoted to introducing the formal theory-a description of polarization and of nuclear reactions with polarized particles. The remainder of the text describes the physical basis of methods and devices necessary to perform experiments with polarized particles and to measure polarization and polarization effects in nuclear rea...

  2. The Science of String Instruments

    CERN Document Server

    Rossing, Thomas D

    2010-01-01

    Many performing musicians, as well as instrument builders, are coming to realize the importance of understanding the science of musical instruments. This book explains how string instruments produce sound. It presents basic ideas in simple language, and it also translates some more sophisticated ideas in non-technical language. It should be of interest to performers, researchers, and instrument makers alike.

  3. Few-body experiments with polarized beams and polarized targets

    International Nuclear Information System (INIS)

    Simmons, J.E.

    1983-01-01

    A survey is presented concerning recent polarization experiments in the elastic p-d, p- 3 He, and p- 4 He systems. Mention is made of selected neutron experiments. The nominal energy range is 10 to 1000 MeV. Recent results and interpretations of the p-d system near 10 MeV are discussed. New experiments on the energy dependence of back angle p-d tensor polarization are discussed with respect to resolution of discrepancies and difficulty of theoretical interpretation. Progress is noted concerning multiple scattering interpretation of forward p-d deuteron polarization. Some new results are presented concerning the p- 3 He system and higher energy p- 4 He polarization experiments. 52 references

  4. Thermodynamics of polarized relativistic matter

    Energy Technology Data Exchange (ETDEWEB)

    Kovtun, Pavel [Department of Physics and Astronomy, University of Victoria,PO Box 1700 STN CSC, Victoria BC, V8W 2Y2 (Canada)

    2016-07-05

    We give the free energy of equilibrium relativistic matter subject to external gravitational and electromagnetic fields, to one-derivative order in the gradients of the external fields. The free energy allows for a straightforward derivation of bound currents and bound momenta in equilibrium. At leading order, the energy-momentum tensor admits a simple expression in terms of the polarization tensor. Beyond the leading order, electric and magnetic polarization vectors are intrinsically ambiguous. The physical effects of polarization, such as the correlation between the magneto-vortically induced surface charge and the electro-vortically induced surface current, are not ambiguous.

  5. Ejectile polarization and nuclear orbitals

    International Nuclear Information System (INIS)

    Ohnishi, A.; Maruyama, T.; Horiuchi, H.

    1992-01-01

    Ejectile polarization phenomena are studied by the use of 'Quantum Molecular Dynamics plus external mean field' model. It is shown that the far-side contribution increases as the incident energy increases or the target charge decreases. The incident energy and the target dependence of ejectile polarization data is reproduced qualitatively. The near- and far-side contributions themselves are calculated to be almost monotone functions of ejectile momentum as is predicted in a simple projectile fragmentation scheme without the assumption that the linear and angular momentum transfers are negligible, and their statistical average results in various shapes in ejectile polarization

  6. Acceleration of polarized proton beams

    International Nuclear Information System (INIS)

    Roser, T.

    1998-01-01

    The acceleration of polarized beams in circular accelerators is complicated by the numerous depolarizing spin resonances. Using a partial Siberian snake and a rf dipole that ensure stable adiabatic spin motion during acceleration has made it possible to accelerate polarized protons to 25 GeV at the Brookhaven AGS. Full Siberian snakes are being developed for RHIC to make the acceleration of polarized protons to 250 GeV possible. A similar scheme is being studied for the 800 GeV HERA proton accelerator

  7. Membrane Transport across Polarized Epithelia.

    Science.gov (United States)

    Garcia-Castillo, Maria Daniela; Chinnapen, Daniel J-F; Lencer, Wayne I

    2017-09-01

    Polarized epithelial cells line diverse surfaces throughout the body forming selective barriers between the external environment and the internal milieu. To cross these epithelial barriers, large solutes and other cargoes must undergo transcytosis, an endocytic pathway unique to polarized cell types, and significant for the development of cell polarity, uptake of viral and bacterial pathogens, transepithelial signaling, and immunoglobulin transport. Here, we review recent advances in our knowledge of the transcytotic pathway for proteins and lipids. We also discuss briefly the promise of harnessing the molecules that undergo transcytosis as vehicles for clinical applications in drug delivery. Copyright © 2017 Cold Spring Harbor Laboratory Press; all rights reserved.

  8. PolarHub: A Global Hub for Polar Data Discovery

    Science.gov (United States)

    Li, W.

    2014-12-01

    This paper reports the outcome of a NSF project in developing a large-scale web crawler PolarHub to discover automatically the distributed polar dataset in the format of OGC web services (OWS) in the cyberspace. PolarHub is a machine robot; its goal is to visit as many webpages as possible to find those containing information about polar OWS, extract this information and store it into the backend data repository. This is a very challenging task given huge data volume of webpages on the Web. Three unique features was introduced in PolarHub to make it distinctive from earlier crawler solutions: (1) a multi-task, multi-user, multi-thread support to the crawling tasks; (2) an extensive use of thread pool and Data Access Object (DAO) design patterns to separate persistent data storage and business logic to achieve high extendibility of the crawler tool; (3) a pattern-matching based customizable crawling algorithm to support discovery of multi-type geospatial web services; and (4) a universal and portable client-server communication mechanism combining a server-push and client pull strategies for enhanced asynchronous processing. A series of experiments were conducted to identify the impact of crawling parameters to the overall system performance. The geographical distribution pattern of all PolarHub identified services is also demonstrated. We expect this work to make a major contribution to the field of geospatial information retrieval and geospatial interoperability, to bridge the gap between data provider and data consumer, and to accelerate polar science by enhancing the accessibility and reusability of adequate polar data.

  9. Polarized deuteron elastic scattering from a polarized proton target

    Energy Technology Data Exchange (ETDEWEB)

    Schmelzer, R.; Kuiper, H.; Schoeberl, M.; Berber, S.; Hilmert, H.; Koeppel, R.; Pferdmenges, R. (Erlangen-Nuernberg Univ., Erlangen (Germany, F.R.). Physikalisches Inst.); Zankel, H. (Graz Univ. (Austria). Inst. fuer Theoretische Physik)

    1983-01-13

    Measurements are reported of the spin correlation parameter Cy,y for the elastic scattering of 10.0 MeV vector polarized deuterons from a polarized proton target at five CM angles (76/sup 0/,85/sup 0/,98/sup 0/,115/sup 0/,132/sup 0/). The experimental results are compared with different predictions. A Faddeev type calculation on the basis of local potentials also including approximate Coulomb distortion is favoured by our experimental results.

  10. Polarized deuteron elastic scattering from a polarized proton target

    International Nuclear Information System (INIS)

    Schmelzer, R.; Kuiper, H.; Schoeberl, M.; Berber, S.; Hilmert, H.; Koeppel, R.; Pferdmenges, R.; Zankel, H.

    1983-01-01

    Measurements are reported of the spin correlation parameter Cy,y for the elastic scattering of 10.0 MeV vector polarized deuterons from a polarized proton target at five CM angles (76 0 ,85 0 ,98 0 ,115 0 ,132 0 ). The experimental results are compared with different predictions. A Faddeev type calculation on the basis of local potentials also including approximate Coulomb distortion is favoured by our experimental results. (orig.)

  11. Photonic Crystal Polarizing and Non-Polarizing Beam Splitters

    International Nuclear Information System (INIS)

    Chun-Ying, Guan; Jin-Hui, Shi; Li-Boo, Yuan

    2008-01-01

    A polarizing beam splitter (PBS) and a non-polarizing beam splitter (NPBS) based on a photonic crystal (PC) directional coupler are demonstrated. The photonic crystal directional coupler consists of a hexagonal lattice of dielectric pillars in air and has a complete photonic band gap. The photonic band structure and the band gap map are calculated using the plane wave expansion (PWE) method. The splitting properties of the splitter are investigated numerically using the finite difference time domain (FDTD) method

  12. netherland hydrological modeling instrument

    Science.gov (United States)

    Hoogewoud, J. C.; de Lange, W. J.; Veldhuizen, A.; Prinsen, G.

    2012-04-01

    Netherlands Hydrological Modeling Instrument A decision support system for water basin management. J.C. Hoogewoud , W.J. de Lange ,A. Veldhuizen , G. Prinsen , The Netherlands Hydrological modeling Instrument (NHI) is the center point of a framework of models, to coherently model the hydrological system and the multitude of functions it supports. Dutch hydrological institutes Deltares, Alterra, Netherlands Environmental Assessment Agency, RWS Waterdienst, STOWA and Vewin are cooperating in enhancing the NHI for adequate decision support. The instrument is used by three different ministries involved in national water policy matters, for instance the WFD, drought management, manure policy and climate change issues. The basis of the modeling instrument is a state-of-the-art on-line coupling of the groundwater system (MODFLOW), the unsaturated zone (metaSWAP) and the surface water system (MOZART-DM). It brings together hydro(geo)logical processes from the column to the basin scale, ranging from 250x250m plots to the river Rhine and includes salt water flow. The NHI is validated with an eight year run (1998-2006) with dry and wet periods. For this run different parts of the hydrology have been compared with measurements. For instance, water demands in dry periods (e.g. for irrigation), discharges at outlets, groundwater levels and evaporation. A validation alone is not enough to get support from stakeholders. Involvement from stakeholders in the modeling process is needed. There fore to gain sufficient support and trust in the instrument on different (policy) levels a couple of actions have been taken: 1. a transparent evaluation of modeling-results has been set up 2. an extensive program is running to cooperate with regional waterboards and suppliers of drinking water in improving the NHI 3. sharing (hydrological) data via newly setup Modeling Database for local and national models 4. Enhancing the NHI with "local" information. The NHI is and has been used for many

  13. Developments in analytical instrumentation

    Science.gov (United States)

    Petrie, G.

    The situation regarding photogrammetric instrumentation has changed quite dramatically over the last 2 or 3 years with the withdrawal of most analogue stereo-plotting machines from the market place and their replacement by analytically based instrumentation. While there have been few new developments in the field of comparators, there has been an explosive development in the area of small, relatively inexpensive analytical stereo-plotters based on the use of microcomputers. In particular, a number of new instruments have been introduced by manufacturers who mostly have not been associated previously with photogrammetry. Several innovative concepts have been introduced in these small but capable instruments, many of which are aimed at specialised applications, e.g. in close-range photogrammetry (using small-format cameras); for thematic mapping (by organisations engaged in environmental monitoring or resources exploitation); for map revision, etc. Another innovative and possibly significant development has been the production of conversion kits to convert suitable analogue stereo-plotting machines such as the Topocart, PG-2 and B-8 into fully fledged analytical plotters. The larger and more sophisticated analytical stereo-plotters are mostly being produced by the traditional mainstream photogrammetric systems suppliers with several new instruments and developments being introduced at the top end of the market. These include the use of enlarged photo stages to handle images up to 25 × 50 cm format; the complete integration of graphics workstations into the analytical plotter design; the introduction of graphics superimposition and stereo-superimposition; the addition of correlators for the automatic measurement of height, etc. The software associated with this new analytical instrumentation is now undergoing extensive re-development with the need to supply photogrammetric data as input to the more sophisticated G.I.S. systems now being installed by clients, instead

  14. Detecting Changing Polarization Structures in Sagittarius A* with High Frequency VLBI

    Science.gov (United States)

    Fish, Vincent L.; Doeleman, Sheperd S.; Broderick, Avery E.; Loeb, Abraham; Rogers, Alan E. E.

    2009-12-01

    Sagittarius A* is the source of near infrared, X-ray, radio, and (sub)millimeter emission associated with the supermassive black hole at the Galactic Center. In the submillimeter regime, Sgr A* exhibits time-variable linear polarization on timescales corresponding to errors. Although the source-integrated linear polarization fraction in the models is typically only a few percent, the linear polarization fraction on small angular scales can be much higher, enabling the detection of changes in the polarimetric structure of Sgr A* on a wide variety of baselines. The shortest baselines track the source-integrated linear polarization fraction, while longer baselines are sensitive to polarization substructures that are beam-diluted by connected-element interferometry. The detection of periodic variability in source polarization should not be significantly affected even if instrumental polarization terms cannot be calibrated out. As more antennas are included in the (sub)millimeter-VLBI array, observations with full polarization will provide important new diagnostics to help disentangle intrinsic source polarization from Faraday rotation effects in the accretion and outflow region close to the black hole event horizon.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-12-20

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

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

    International Nuclear Information System (INIS)

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

    2016-01-01

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

  17. Extreme-Scale Alignments Of Quasar Optical Polarizations And Galactic Dust Contamination

    Science.gov (United States)

    Pelgrims, Vincent

    2017-10-01

    Almost twenty years ago the optical polarization vectors from quasars were shown to be aligned over extreme-scales. That evidence was later confirmed and enhanced thanks to additional optical data obtained with the ESO instrument FORS2 mounted on the VLT, in Chile. These observations suggest either Galactic foreground contamination of the data or, more interestingly, a cosmological origin. Using 353-GHz polarization data from the Planck satellite, I recently showed that the main features of the extreme-scale alignments of the quasar optical polarization vectors are unaffected by the Galactic thermal dust. This confirms previous studies based on optical starlight polarization and discards the scenario of Galactic contamination. In this talk, I shall briefly review the extreme-scale quasar polarization alignments, discuss the main results submitted in A&A and motivate forthcoming projects at the frontier between Galactic and extragalactic astrop hysics.

  18. Time-reversal asymmetry: polarization and analyzing power in nuclear reactions

    International Nuclear Information System (INIS)

    Rioux, C.; Roy, R.; Slobodrian, R.J.; Conzett, H.E.

    1984-01-01

    Measurements of the proton polarization in the reactions 7 Li( 3 He, p vector) 9 Be and 9 Be( 3 He, p vector) 11 B and of the analyzing powers in the inverse reactions, initiated by polarized protons at the same center-of-mass energies, show significant differences. This implies the failure of the polarization-analyzing-power theorem and, prima facie, of time-reversal invariance in these reactions. The reaction 2 H( 3 He, p vector) 4 He and its inverse have also been investigated and show smaller differences. A discussion of instrumental asymmetries is presented

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

    International Nuclear Information System (INIS)

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

    1992-01-01

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

  20. Data acquisition instruments: Psychopharmacology

    Energy Technology Data Exchange (ETDEWEB)

    Hartley, D.S. III

    1998-01-01

    This report contains the results of a Direct Assistance Project performed by Lockheed Martin Energy Systems, Inc., for Dr. K. O. Jobson. The purpose of the project was to perform preliminary analysis of the data acquisition instruments used in the field of psychiatry, with the goal of identifying commonalities of data and strategies for handling and using the data in the most advantageous fashion. Data acquisition instruments from 12 sources were provided by Dr. Jobson. Several commonalities were identified and a potentially useful data strategy is reported here. Analysis of the information collected for utility in performing diagnoses is recommended. In addition, further work is recommended to refine the commonalities into a directly useful computer systems structure.

  1. Social Responsibility Instruments

    Directory of Open Access Journals (Sweden)

    Katarzyna Mizera

    2008-09-01

    Full Text Available Responsible business notion is more and more present in Polish economy, however the results of the research carried out in Polish business still shows a low level of CRS idea knowledge, especially in small and medium companies. Although responsible business notion is generally known, its details, ways of preparing strategy, instruments and what is more its benefits are still narrowly spread. Many business people face the lack of knowledge and information, which on one hand make it easier to spread and deepen wrong stereotypes connected with this notion and on the other hand make business people unwilling to implement CRS in their companies. The subjects of this article are examples of instruments which are responsible for realization of social responsibility strategy.

  2. Radiation measuring instrument

    International Nuclear Information System (INIS)

    Genrich, V.

    1985-01-01

    A highly sensitive and compactly structured radiation measuring instrument for detecting ionizing radiation, in particular for measuring dose rates and contamination. The laminar structure of the associated counter tube, using only a few, simple plastic parts and a highly elastic counter wire, makes it possible to use the simplest manufacturing techniques. The service life of the counter tube construction, which is completely and permanently sealed and filled with gas, is expected to be more than 12 years. The described counter tube can be adapted in optimal fashion to the available space in a pocket instrument if it is used in combination with a specialized high-voltage generator which is low in interference voltage and with a pulse evaluation circuit having a means of compensating for interference voltage

  3. Mean energy polarized neutron source

    International Nuclear Information System (INIS)

    Aleshin, V.A.; Zaika, N.I.; Kolotyj, V.V.; Prokopenko, V.S.; Semenov, V.S.

    1988-01-01

    Physical bases and realization scheme of a pulsed source of polarized neutrons with the energy of up to 75 MeV are described. The source comprises polarized deuteron source, transport line, low-energy ion and axial injector to the accelerator, U-240 isochronous cyclotron, targets for polarized neutron production, accelerated deuteron transport line and flight bases. The pulsed source of fast neutrons with the energy of up to 75 MeV can provide for highly polarized neutron beams with the intensity by 2-3 orders higher than in the most perfect source of this range which allows one to perform various experiments with high efficiency and energy resolution. 9 refs.; 1 fig

  4. Circular polarization observed in bioluminescence

    NARCIS (Netherlands)

    Wynberg, H.; Meijer, E.W.; Hummelen, J.C.; Dekkers, H.P.J.M.; Schippers, P.H.; Carlson, A.D.

    1980-01-01

    The left and right lanterns of live larvae of the fireflies Photuris lucicrescens and P. versicolor emitted circularly polarized light of opposite sense. A possible mechanism is discussed. [on SciFinder (R)

  5. The definition of cross polarization

    DEFF Research Database (Denmark)

    Ludwig, Arthur

    1973-01-01

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

  6. Polar source analysis : technical memorandum

    Science.gov (United States)

    2017-09-29

    The following technical memorandum describes the development, testing and analysis of various polar source data sets. The memorandum also includes recommendation for potential inclusion in future releases of AEDT. This memorandum is the final deliver...

  7. Dynamic elections and ideological polarization

    Czech Academy of Sciences Publication Activity Database

    Nunnari, S.; Zápal, Jan

    2017-01-01

    Roč. 25, č. 4 (2017), s. 505-534 ISSN 1047-1987 Institutional support: RVO:67985998 Keywords : elections * political polarization Subject RIV: AH - Economics OBOR OECD: Economic Theory Impact factor: 3.361, year: 2016

  8. Dynamic elections and ideological polarization

    Czech Academy of Sciences Publication Activity Database

    Nunnari, S.; Zápal, Jan

    2017-01-01

    Roč. 25, č. 4 (2017), s. 505-534 ISSN 1047-1987 Institutional support: Progres-Q24 Keywords : elections * political polarization Subject RIV: AH - Economics OBOR OECD: Economic Theory Impact factor: 3.361, year: 2016

  9. Polarization at LEP. Vol. 2

    International Nuclear Information System (INIS)

    Alexander, G.; Altarelli, G.; Blondel, A.; Coignet, G.; Keil, E.; Plane, D.E.; Treille, D.

    1988-01-01

    This report contains a collection of papers covering the most important part of studies carried out by five study groups in view of a programme of experiments with polarized beams at LEP, the Large Electron-Positron collider under construction at CERN. The emphasis is on precision measurements at the Z peak. Such measurements are shown to be of considerable theoretical interest as well as very clean from the point of view of theoretical and experimental uncertainties. The measurement of the beam polarization can certainly be performed with sufficient accuracy, thanks to the availability of both e + and e - beam polarization. The normalization of the data taken with different beam helicities poses certain constraints that are described. Substantial progress has been made in understanding the possibility of providing longitudinally polarized beams in the LEP machine: The design of new wigglers and spin rotators, the study of correction procedures and results of numerical simulations are presented. (orig.)

  10. Modeling optical and UV polarization of AGNs. IV. Polarization timing

    Science.gov (United States)

    Rojas Lobos, P. A.; Goosmann, R. W.; Marin, F.; Savić, D.

    2018-03-01

    Context. Optical observations cannot resolve the structure of active galactic nuclei (AGN), and a unified model for AGN was inferred mostly from indirect methods, such as spectroscopy and variability studies. Optical reverberation mapping allowed us to constrain the spatial dimension of the broad emission line region and thereby to measure the mass of supermassive black holes. Recently, reverberation was also applied to the polarized signal emerging from different AGN components. In principle, this should allow us to measure the spatial dimensions of the sub-parsec reprocessing media. Aim. We conduct numerical modeling of polarization reverberation and provide theoretical predictions for the polarization time lag induced by different AGN components. The model parameters are adjusted to the observational appearance of the Seyfert 1 galaxy NGC 4151. Methods: We modeled scattering-induced polarization and tested different geometries for the circumnuclear dust component. Our tests included the effects of clumpiness and different dust prescriptions. To further extend the model, we also explored the effects of additional ionized winds stretched along the polar direction, and of an equatorial scattering ring that is responsible for the polarization angle observed in pole-on AGN. The simulations were run using a time-dependent version of the STOKES code. Results: Our modeling confirms the previously found polarization characteristics as a function of the observer`s viewing angle. When the dust adopts a flared-disk geometry, the lags reveal a clear difference between type 1 and type 2 AGN. This distinction is less clear for a torus geometry where the time lag is more sensitive to the geometry and optical depth of the inner surface layers of the funnel. The presence of a scattering equatorial ring and ionized outflows increased the recorded polarization time lags, and the polar outflows smooths out dependence on viewing angle, especially for the higher optical depth of the

  11. Radon-Instrumentation

    International Nuclear Information System (INIS)

    Moreno y Moreno, A.

    2003-01-01

    The presentation of the active and passive methods for radon, their identification and measure, instrumentation and characteristics are the objectives of this work. Active detectors: Active Alpha Cam Continuous Air Monitor, Model 758 of Victoreen, Model CMR-510 Continuous Radon Monitor of the Signature Femto-Tech. Passive detectors: SSNTD track detectors in solids Measurement Using Charcoal Canisters, disk of activated coal deposited in a metallic box Electrets Methodology. (Author)

  12. Testing Aircraft Instruments.

    Science.gov (United States)

    1981-02-11

    1. Have test data been collected, recorded, and presented in accordance with this TOP? Yes No Comment : 2. Were the facilities, test equipment...instrumentation, and support accommodations adequate to accomplish the test objectives? Yes No Comment : 3. Have all data collected been reviewed for...correctness and completeness? Yes No Comment : 4. Were the test results compromised in any way due to insufficient test planning? Yes No Comment : 5. Were the

  13. Transgressive or Instrumental?

    DEFF Research Database (Denmark)

    Chemi, Tatiana

    2018-01-01

    Contemporary practices that connect the arts with learning are widespread at all level of educational systems and in organisations, but they include very diverse approaches, multiple methods and background values. Regardless of explicit learning benefits, the arts/learning partnerships bring about...... creativity and the other on practices of arts-integration. My final point rests on the belief that the opposition of transgression and instrumentality is a deceiving perspective on the arts, against the background of the aesthetic plurality and hybridity....

  14. Spin exchange optical pumping based polarized 3He filling station for the Hybrid Spectrometer at the Spallation Neutron Source.

    Science.gov (United States)

    Jiang, C Y; Tong, X; Brown, D R; Culbertson, H; Graves-Brook, M K; Hagen, M E; Kadron, B; Lee, W T; Robertson, J L; Winn, B

    2013-06-01

    The Hybrid Spectrometer (HYSPEC) is a new direct geometry spectrometer at the Spallation Neutron Source at the Oak Ridge National Laboratory. This instrument is equipped with polarization analysis capability with 60° horizontal and 15° vertical detector coverages. In order to provide wide angle polarization analysis for this instrument, we have designed and built a novel polarized (3)He filling station based on the spin exchange optical pumping method. It is designed to supply polarized (3)He gas to HYSPEC as a neutron polarization analyzer. In addition, the station can optimize the (3)He pressure with respect to the scattered neutron energies. The depolarized (3)He gas in the analyzer can be transferred back to the station to be repolarized. We have constructed the prototype filling station. Preliminary tests have been carried out demonstrating the feasibility of the filling station. Here, we report on the design, construction, and the preliminary results of the prototype filling station.

  15. Solid Polarized Targets and Applications

    International Nuclear Information System (INIS)

    Crabb, D. G.

    2008-01-01

    Examples are given of dynamically polarized targets in use today and how the subsystems have changed to meet the needs of todays experiments. Particular emphasis is placed on target materials such as ammonia and lithium deuteride. Recent polarization studies of irradiated materials such as butanol, deuterated butanol, polyethylene, and deuterated polyethylene are presented. The operation of two non-DNP target systems as well as applications of traditional DNP targets are briefly discussed

  16. Polarization bremsstrahlung in α decay

    International Nuclear Information System (INIS)

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

    2007-01-01

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

  17. EPRTM Reactor neutron instrumentation

    International Nuclear Information System (INIS)

    Pfeiffer, Maxime; SALA, Stephanie

    2013-06-01

    The core safety during operation is linked, in particular, to the respect of criteria related to the heat generated in fuel rods and to the heat exchange between the rods and the coolant. This local power information is linked to the power distribution in the core. In order to evaluate the core power distribution, the EPR TM reactor relies on several types of neutron detectors: - ionization chambers located outside the vessel and used for protection and monitoring - a fixed in-core instrumentation based on Cobalt Self Powered Neutron Detectors used for protection and monitoring - a mobile reference in-core instrumentation based on Vanadium aero-balls This document provides a description of this instrumentation and its use in core protection, limitation, monitoring and control functions. In particular, a description of the detectors and the principles of their signal generation is supplied as well as the description of the treatments related to these detectors in the EPR TM reactor I and C systems (including periodical calibration). (authors)

  18. Mandolin Family Instruments

    Science.gov (United States)

    Cohen, David J.; Rossing, Thomas D.

    The mandolin family of instruments consists of plucked chordophones, each having eight strings in four double courses. With the exception of the mandobass, the courses are tuned in intervals of fifths, as are the strings in violin family instruments. The soprano member of the family is the mandolin, tuned G3-D4-A4-E5. The alto member of the family is the mandola, tuned C3-G3-D4-A4. The mandola is usually referred to simply as the mandola in the USA, but is called the tenor mandola in Europe. The tenor member of the family is the octave mandolin, tuned G2-D3-A3-E4. It is referred to as the octave mandolin in the USA, and as the octave mandola in Europe. The baritone member of the family is the mandocello, or mandoloncello, tuned C2-G2-D3-A3. A variant of the mandocello not common in the USA is the five-course liuto moderno, or simply liuto, designed for solo repertoire. Its courses are tuned C2-G2-D3-A3-E4. A mandobass was also made by more than one manufacturer during the early twentieth century, though none are manufactured today. They were fretted instruments with single string courses tuned E1-A1-D2-G2. There are currently a few luthiers making piccolo mandolins, tuned C4-G4-D5-A5.

  19. Nuclear reactor instrumentation

    International Nuclear Information System (INIS)

    Duncombe, E.; McGonigal, G.

    1976-01-01

    Reference is made to the instrumentation of liquid metal cooled fast reactors. In order to ensure the safe operation of such reactors it is necessary to constantly monitor the coolant flowing through the fuel assemblies for temperature and rate of flow, requiring a large number of sensors. An improved and simplified arrangement is claimed in which the fuel assemblies feed a fraction of coolant to three instrument units arranged to sense the temperature and rate of flow of samples of coolant. Each instrument unit comprises a sleeve housing a sensing unit and has a number of inlet ducts arranged for receiving coolant from a fuel assembly together with a single outlet. The sensing unit has three thermocouple hot junctions connected in series, the hot junctions and inlet ducts being arranged in pairs. Electromagnetic windings around an inductive core are arranged to sense variation in flow of liquid metal by flux distortion. Fission product sensing means may also be provided. Full constructional details are given. (U.K.)

  20. New polarizing guide for neutron wavelengths above 2.5 A

    Energy Technology Data Exchange (ETDEWEB)

    Krist, Th; Pappas, C; Teichert, A; Fehr, C; Clemens, D; Steichele, E; Mezei, F, E-mail: krist@helmholtz-berlin.de

    2010-11-01

    We present a new polarizing system built for the relocated wide angle Neutron Spin Echo instrument SPAN. The new instruments at the second Guide Hall of BENSC and the relocation of SPAN to this hall of BENSC required a new beam extraction system and a new polarizer for SPAN, which replaced the old beam splitter produced in 1994 with FeCo-Si supermirrors with m=2. The new polarizer uses Fe-Si supermirrors, which do not run the risk to become activated as the old FeCo-Si supermirrors and was designed to deliver a polarized beam for wavelengths above 2.5 A. The final polarizing cavity has a length of 9 m with a cross section of 60 mm x 100 mm. Si wafers coated on both sides with m=2.5 Fe-Si polarizing supermirrors are glued into the guide at an angle of 0.38{sup 0} to the walls. The guide was installed during the second half year of 2006 and the first tests in early 2007 revealed excellent polarization efficiency over the whole wavelength range of the spectrometer of 2.5 A to 9 A, amounting to above 95% at 4.5 A.