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Results for “Polarimeter”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 217 records · Page 12
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Thermal and electromechanical response of ultra-thin carbon-strip polarimeter targets in relativistic bunched beams

Thin carbon-strip targets provide fast relative hadron beam polarimetry, but their response in intense relativistic bunched beams is not governed by local stopping-power heating alone. We develop a coupled response model that combines beam-target overlap, secondary-electron escape, retained heat, target motion, transient heat transport, RF-induced strip-end heating, beam-induced forces, resistance changes, and slack-strip deformation. RHIC target observations constrain the relevant motion, force, and nonlocal-heating scales and show that target survival depends on both beam-center heating and electromagnetic boundary conditions near the strip ends. Applying the model to Booster, AGS, RHIC, and EIC proton and 3 He cases shows that the RHIC proton lifetime scale is reproduced at the order-of-magnitude level, while the RHIC target-holder fin results require the additional RF/end-heating mechanism. For EIC proton flattop operation, carbon-strip polarimetry may remain viable only with reduced dwell time, sufficient detector acceptance, and suppression of RF-induced end heating. For cooled-emittance 3 He, the calculated sublimation-loss scale is far beyond a straightforward RHIC-like carbon-strip extrapolation. Conventional carbon strips are therefore unlikely to remain viable for the most demanding EIC light-ion cases without major changes in target motion, target technology, or diagnostic concept.

43 PARTICLE ACCELERATORS↗
NASA NTRS1971

A large area Thomson-scattering stellar X-ray polarimeter.

An instrument for measuring the polarization of stellar X-ray emission has been designed, constructed, and tested. The polarization dependence of incoherent Thomson scattering in lithium metal is utilized. Means for suppression of cosmic ray background effects have been provided. The apparatus has been flown in rockets to obtain data in the polarization of X-ray sources in Sco X-1 and Tau X-1.

Novick, R.↗
NASA NTRS1973

Low-noise microwave polarimeter

Two quarterwave-plate polarizers inserted between rotary waveguide joints transform received signals from arbitrary linear to circular polarizations and then from circular to fixed linear polarizations. Fixed linear polarizations are applied to amplifiers and filters in usual fashion.

Levy, G. S.↗
NASA NTRS1974

Remote measurements of water pollution with a lidar polarimeter

This paper examines a dual polarization laser backscatter system as a method for remote measurements of certain water quality parameters. Analytical models for describing the backscatter from turbid water and oil on turbid water are presented and compared with experimental data. Laser backscatter field measurements from natural waterways are presented and compared with simultaneous ground observations of the water quality parameters: turbidity, suspended solids, and transmittance. The results of this study show that the analytical models appear valid and that the sensor investigated is applicable to remote measurements of these water quality parameters and oil spills on water.-

Sheives, T. C.↗
NASA NTRS1977

A forward-scatter polarimeter for chemical analysis

Photopolarimeter measures two states of orthogonal polarization parallel and perpendicular to scattering plane, defined by directions of incident and scattering light, to determine effective gaseous depolarization factor. Instrument can be used for environmental, spectroscopic, and meteorological analysis.

Fymat, A. L.↗
NASA NTRS1981

Image motion compensation on the Spacelab 2 Solar Optical Universal Polarimeter /SL2 SOUP/

The SOUP experiment on Spacelab 2 includes a 30 cm visible light telescope and focal plane package mounted on the Instrument Pointing System (IPS). Scientific goals of the experiment dictate pointing stability requirements of less than 0.05 arcsecond jitter over periods of 5-20 seconds. Quantitative derivations of these requirements from two different aspects are presented: (1) avoidance of motion blurring of diffraction-limited images; (2) precise coalignment of consecutive frames to allow measurement of small image differences. To achieve this stability, a fine guider system capable of removing residual jitter of the IPS and image motions generated on the IPS cruciform instrument support structure has been constructed. This system uses solar limb detectors in the prime focal plane to derive an error signal. Image motion due to pointing errors is compensated by the agile secondary mirror mounted on piezoelectric transducers, controlled by a closed-loop servo system.

Tarbell, T. D.↗
NASA NTRS1981

Video image processor on the Spacelab 2 Solar Optical Universal Polarimeter /SL2 SOUP/

The SOUP instrument is designed to obtain diffraction-limited digital images of the sun with high photometric accuracy. The Video Processor originated from the requirement to provide onboard real-time image processing, both to reduce the telemetry rate and to provide meaningful video displays of scientific data to the payload crew. This original concept has evolved into a versatile digital processing system with a multitude of other uses in the SOUP program. The central element in the Video Processor design is a 16-bit central processing unit based on 2900 family bipolar bit-slice devices. All arithmetic, logical and I/O operations are under control of microprograms, stored in programmable read-only memory and initiated by commands from the LSI-11. Several functions of the Video Processor are described, including interface to the High Rate Multiplexer downlink, cosmetic and scientific data processing, scan conversion for crew displays, focus and exposure testing, and use as ground support equipment.

Lindgren, R. W.↗
NASA NTRS1982

Measurements of solar transition zone velocities and line broadening using the ultraviolet spectrometer and polarimeter on the Solar Maximum Mission

The UVSP instrument on SMM is able to observe solar regions at two wavelengths in the same line with a band-pass of 0.3 A. Intensity and Doppler velocity maps are derived. It is shown that the numerical values are sensitive to the adopted Doppler width and the range of velocities is limited to within 30 km/sec. A method called Double Dopplergram Determination (DDD) is described for deriving both the Doppler width and the velocity (up to 80 km/sec), and the main sources of uncertainties are discussed. To illustrate the method, a set of C IV 1548 A observations is analyzed according to this procedure. The mean C IV Doppler width measured (0.15 A) is comparable to previous determinations. A relation is found between bright regions and down-flows. Large Doppler widths correspond to strong velocity gradients.

Simon, G.↗
NASA NTRS1986

Ultraviolet spectrometer and polarimeter (UVSP) software development and hardware tests for the solar maximum mission

The Ultraviolet Spectrometer/Polarimeter Instrument (UVSP) for the Solar Maximum Mission (SMM) was based on the re-use of the engineering model of the high resolution ultraviolet spectrometer developed for the OSO-8 mission. Lockheed assumed four distinct responsibilities in the UVSP program: technical evaluation of the OSO-8 engineering model; technical consulting on the electronic, optical, and mechanical modifications to the OSO-8 engineering model hardware; design and development of the UVSP software system; and scientific participation in the operations and analysis phase of the mission. Lockheed also provided technical consulting and assistance with instrument hardware performance anomalies encountered during the post launch operation of the SMM observatory. An index to the quarterly reports delivered under the contract are contained, and serves as a useful capsule history of the program activity.

Bruner, M. E.↗
NASA NTRS1987

Imaging Radar Polarimeter

Radar measures full polarization tensor of each element in scene in one sweep. New system comprises dual-polarized antenna, single transmitter, and four-channel receiver and digital recorder installed in aircraft, plus digital processor on ground. Produces radar-backscatter images corresponding to 10- by 10-km regions on ground. Signals recorded from orthogonal linearly polarized antennas combined in computer after flight to synthesize any desired combination of transmitted and received polarizations. Data recorded on single flight processed to provide multiple images.

Zebker, Howard A.↗
NASA NTRS1987

Exploration of the solar-stellar connection at high spectral resolution with the Ultraviolet Spectrometer and Polarimeter, and studies of thermal bifurcation at the photosphere-chromosphere interface

The dynamics of high-excitation plasma in the 100,000 K transition zones of stars of late spectral type, as observed with the International Ultraviolet Explorer, was compared with the radial gas velocities of individual structural features of the solar TZ, as observed with high spatial resolution by the UVSP on the Solar Maximum Mission. The 4th-positive system of carbon monoxide in the quiet sun and in active regions was studied in order to explore the properties of thermal inhomogeneities at the critical interface between the photosphere and chromosphere.

Source record↗
NASA NTRS1989

Radar Polarimeter Measures Orientations Of Retroreflectors

Polarization signatures of targets compared with known signatures at known angles. Experiments demonstrated use of radar polarimetry to measure orientation of retroreflective target, even though target much smaller than resolution element of radar. Technique based on comparison of angular dependencies of measured and theoretically derived polarization signatures of target. Polarization signature also used to identify target. Tilt of reflector inferred by finding angle minimizing measure of difference between theoretical and measured radar cross sections of reflector.

Zebker, H. A.↗