Science.gov

Sample records for single-pass radar interferometer

  1. The Glacier and Ice Surface Topography Interferometer: UAVSAR's Single-pass Ka-Band Interferometer

    NASA Astrophysics Data System (ADS)

    Moller, D.; Hensley, S.; Sadowy, G.; Wu, X.; Carswell, J.; Fisher, C.; Michel, T.; Lou, Y.

    2012-12-01

    In May 2009 a new radar technique for mapping ice surface topography was demonstrated in a Greenland campaign as part of the NASA International Polar Year (IPY) activities. This was achieved with the airborne Glacier and Ice Surface Topography Interferometer (GLISTIN-A): a 35.6 GHz single-pass interferometer. Although the technique of using radar interferometry for mapping terrain has been demonstrated before, this is the first such application at millimeter-wave frequencies. The proof-of-concept demonstration was achieved by interfacing Ka-band RF and antenna hardware with the Uninhabited Airborne Vehicle Synthetic Aperture Radar (UAVSAR). The GLISTIN-A was implemented as a custom installation of the NASA Dryden Flight Research Center Gulfstream III. Instrument performance indicates swath widths over the ice between 5-7km, with height precisions ranging from 30cm-3m at a posting of 3m x 3m. Processing challenges were encountered in achieving the accuracy requirements on several fronts including, aircraft motion sensitivity, multipath and systematic drifts. However, through a combination of processor optimization, a modified phase-screen and motion-compensation implementations were able to minimize the impact of these systematic error sources. We will present results from the IPY data collections including system performance evaluations and imagery. This includes a large area digital elevation model (DEM) collected over Jakobshavn glacier as an illustrative science data product. Further, by intercomparison with the NASA Wallops Airborne Topographic Mapper (ATM) and calibration targets we quantify the interferometric penetration bias of the Ka-band returns into the snow cover. Following the success of the IPY campaign, we are funded under the Earth Science Techonology Office (ESTO) Airborne Innovative Technology Transition (AITT) program to transition GLISTIN-A to a permanently-available pod-only system compatible with unpressurized operation. In addition

  2. The Glacier and Ice Surface Topography Interferometer: UAVSAR's Single-pass Ka-Band Interferometer

    NASA Astrophysics Data System (ADS)

    Moller, D.; Hensley, S.; Wu, X.; Michel, T.; Muellerschoen, R.; Carswell, J.; Fisher, C.; Miller, T.; Milligan, L.; Sadowy, G.; Sanchez-Barbetty, M.; Lou, Y.

    2013-12-01

    In May 2009 a new radar technique for mapping ice surface topography was demonstrated in a Greenland campaign as part of the NASA International Polar Year (IPY) activities. This was achieved with the airborne Glacier and Ice Surface Topography Interferometer (GLISTIN-A): a 35.6 GHz single-pass interferometer. The proof-of-concept demonstration was achieved by interfacing Ka-band RF and antenna hardware with the Uninhabited Airborne Vehicle Synthetic Aperture Radar (UAVSAR). The GLISTIN-A was implemented as a custom installation of the NASA Dryden Flight Research Center Gulfstream III. Instrument performance indicated swath widths over the ice between 5-7km, with height precisions ranging from 30cm-3m at a posting of 3m x 3m. Following the success of the IPY campaign, the Earth Science Techonology Office (ESTO) Airborne Innovative Technology Transition (AITT) program funded the upgrade of GLISTIN-A to a permanently-available pod-only system compatible with unpressurized operation. The AITT made three fundamental upgrades to improve system performance: 1. State-of-the-art solid-state power amplifiers (80W peak) were integrated directly on the antenna panel reducing front-end losses; 2. A ping-pong capability was incorporated to effectively double the baseline thereby improving height measurement precision by a factor of two; and 3. A high-fidelity calibration loop was implemented which is critical for routine processing. Upon completion of our engineering flights in February 2013, GLISTIN-A flew a brief campaign to Alaska (4/24-4/27/13). The purpose was to fully demonstrate GLISTIN-A's ability to generate high-precision, high resolution maps of ice surface topography with swaths in excess of 10km. Furthermore, the question of the utility of GLISTIN-A for sea-ice mapping, tracking and inventory has received a great deal of interest. To address this GLISTIN-A collected data over sea-ice in the Beaufort sea including an underflight of CryoSAT II. Note that there are

  3. EcoSAR: NASA's P-band fully polarimetric single pass interferometric airborne radar

    NASA Astrophysics Data System (ADS)

    Osmanoglu, B.; Rincon, R. F.; Fatoyinbo, T. E.; Lee, S. K.; Sun, G.; Daniyan, O.; Harcum, M. E.

    2014-12-01

    EcoSAR is a new airborne synthetic aperture radar imaging system, developed at the NASA Goddard Space Flight Center. It is a P-band sensor that employs a non-conventional and innovative design. The EcoSAR system was designed as a multi-disciplinary instrument to image the 3-dimensional surface of the earth from a single pass platform with two antennas. EcoSAR's principal mission is to penetrate the forest canopy to return vital information about the canopy structure and estimate biomass. With a maximum bandwidth of 200 MHz in H and 120 MHz in V polarizations it can provide sub-meter resolution imagery of the study area. EcoSAR's dual antenna, 32 transmit and receive channel architecture provides a test-bed for developing new algorithms in InSAR data processing such as single pass interferometry, full polarimetry, post-processing synthesis of multiple beams, simultaneous measurement over both sides of the flight track, selectable resolution and variable incidence angle. The flexible architecture of EcoSAR will create new opportunities in radar remote sensing of forest biomass, permafrost active layer thickness, and topography mapping. EcoSAR's first test flight occurred between March 27th and April 1st, 2014 over the Andros Island in Bahamas and Corcovado and La Selva National Parks in Costa Rica. The 32 channel radar system collected about 6 TB of radar data in about 12 hours of data collection. Due to the existence of radio and TV communications in the operational frequency band, acquired data contains strong radar frequency interference, which had to be removed prior to beamforming and focusing. Precise locations of the antennas are tracked using high-rate GPS and inertial navigation units, which provide necessary information for accurate processing of the imagery. In this presentation we will present preliminary imagery collected during the test campaign, show examples of simultaneous dual track imaging, as well as a single pass interferogram. The

  4. Orbit Determination of LEO Satellites for a Single Pass through a Radar: Comparison of Methods

    NASA Technical Reports Server (NTRS)

    Khutorovsky, Z.; Kamensky, S.; Sbytov, N.; Alfriend, K. T.

    2007-01-01

    The problem of determining the orbit of a space object from measurements based on one pass through the field of view of a radar is not a new one. Extensive research in this area has been carried out in the USA and Russia since the late 50s when these countries started the development of ballistic missile defense (BMD) and Early Warning systems. In Russia these investigations got additional stimulation in the early 60s after the decision to create a Space Surveillance System, whose primary task would be the maintenance of the satellite catalog. These problems were the focus of research interest until the middle 70s when the appropriate techniques and software were implemented for all radars. Then for more than 20 years no new research papers appeared on this subject. This produced an impression that all the problems of track determination based on one pass had been solved and there was no need for further research. In the late 90s interest in this problem arose again in relation to the following. It was estimated that there would be greater than 100,000 objects with size greater than 1-2 cm and collision of an operational spacecraft with any of these objects could have catastrophic results. Thus, for prevention of hazardous approaches and collisions with valuable spacecraft the existing satellite catalog should be extended by at least an order of magnitude This is a very difficult scientific and engineering task. One of the issues is the development of data fusion procedures and the software capable of maintaining such a huge catalog in near real time. The number of daily processed measurements (of all types, radar and optical) for such a system may constitute millions, thus increasing the number of measurements by at least an order of magnitude. Since we will have ten times more satellites and measurements the computer effort required for the correlation of measurements will be two orders of magnitude greater. This could create significant problems for processing

  5. Information content of a single pass of phase-delay data from a short baseline connected element interferometer

    NASA Technical Reports Server (NTRS)

    Thurman, S. W.

    1990-01-01

    An analytic development of the information array obtained with a single tracking pass of phase-delay measurements made from a short baseline interferometer is presented. Phase-delay observations can be made with great precision from two antennas using a single, common distributed frequency standard, hence the name connected element. With the information array, closed-form expressions are developed for the error covariance in declination and right ascension. These equations serve as useful tools for analyzing the relative merits of candidate station locations for connected element interferometry (CEI). The navigation performance of a short baseline interferometer located at the Deep Space Network's (DSN's) Goldstone intracomplex is compared with that which is presently achievable using Very Long Baseline Interferometry (VLBI) over intercontinental baselines. The performance of an intracomplex pair of short baselines formed by three stations is also investigated, along with the use of a single baseline in conjunction with conventional two-way Doppler data. The phase-delay measurement accuracy and data rate used in the analysis are based on the expected performance of an experimental connected element system presently under construction at Goldstone. The results indicate that the VLBI system that will be used during the Galileo mission can determine the declination and right ascension of a distant spacecraft to an accuracy of 20 to 25 nrad, while the CEI triad system and the combination of CEI-Doppler system are both capable of 30 to 70 nrad performance.

  6. A simplified interferometer design for use with meteor radars

    NASA Astrophysics Data System (ADS)

    Poole, L. M. G.

    2004-04-01

    A relatively simple design for a meteor radar interferometer with 4 receiving antennas is described. A basic 3 element interferometer provides a set of possible directions for each radio echo detected. The ambiguity is resolved using a 4th antenna, placed according to the results of a numerical simulation. Details of the procedure are provided. The resolution in echo direction is between ˜1° and ˜2° for altitudes (elevations) above ˜30° at all azimuths. A general purpose meteor radar based on this principle has been in use since 1986 at Grahamstown, South Africa.

  7. TanDEM-X: A radar interferometer with two formation-flying satellites

    NASA Astrophysics Data System (ADS)

    Krieger, Gerhard; Zink, Manfred; Bachmann, Markus; Bräutigam, Benjamin; Schulze, Daniel; Martone, Michele; Rizzoli, Paola; Steinbrecher, Ulrich; Walter Antony, John; De Zan, Francesco; Hajnsek, Irena; Papathanassiou, Kostas; Kugler, Florian; Rodriguez Cassola, Marc; Younis, Marwan; Baumgartner, Stefan; López-Dekker, Paco; Prats, Pau; Moreira, Alberto

    2013-08-01

    TanDEM-X (TerraSAR-X add-on for Digital Elevation Measurements) is an innovative formation-flying radar mission that opens a new era in spaceborne radar remote sensing. The primary objective is the acquisition of a global digital elevation model (DEM) with unprecedented accuracy (12 m horizontal resolution and 2 m relative height accuracy). This goal is achieved by extending the TerraSAR-X synthetic aperture radar (SAR) mission by a second, TerraSAR-X like satellite (TDX) flying in close formation with TerraSAR-X (TSX). Both satellites form together a large single-pass SAR interferometer with the opportunity for flexible baseline selection. This enables the acquisition of highly accurate cross-track interferograms without the inherent accuracy limitations imposed by repeat-pass interferometry due to temporal decorrelation and atmospheric disturbances. Besides the primary goal of the mission, several secondary mission objectives based on along-track interferometry as well as new bistatic and multistatic SAR techniques have been defined, representing an important and innovative asset of the TanDEM-X mission. TanDEM-X is implemented in the framework of a public-private partnership between the German Aerospace Center (DLR) and EADS Astrium GmbH. The TanDEM-X satellite was successfully launched in June 2010 and the mission started its operational data acquisition in December 2010. This paper provides an overview of the TanDEM-X mission and summarizes its actual status and performance. Furthermore, results from several scientific radar experiments are presented that show the great potential of future formation-flying interferometric SAR missions to serve novel remote sensing applications.

  8. Radar Interferometer for Topographic Mapping of Glaciers and Ice Sheets

    NASA Technical Reports Server (NTRS)

    Moller, Delwyn K.; Sadowy, Gregory A.; Rignot, Eric J.; Madsen, Soren N.

    2007-01-01

    A report discusses Ka-band (35-GHz) radar for mapping the surface topography of glaciers and ice sheets at high spatial resolution and high vertical accuracy, independent of cloud cover, with a swath-width of 70 km. The system is a single- pass, single-platform interferometric synthetic aperture radar (InSAR) with an 8-mm wavelength, which minimizes snow penetration while remaining relatively impervious to atmospheric attenuation. As exhibited by the lower frequency SRTM (Shuttle Radar Topography Mission) AirSAR and GeoSAR systems, an InSAR measures topography using two antennas separated by a baseline in the cross-track direction, to view the same region on the ground. The interferometric combination of data received allows the system to resolve the pathlength difference from the illuminated area to the antennas to a fraction of a wavelength. From the interferometric phase, the height of the target area can be estimated. This means an InSAR system is capable of providing not only the position of each image point in along-track and slant range as with a traditional SAR but also the height of that point through interferometry. Although the evolution of InSAR to a millimeter-wave center frequency maximizes the interferometric accuracy from a given baseline length, the high frequency also creates a fundamental problem of swath coverage versus signal-to-noise ratio. While the length of SAR antennas is typically fixed by mass and stowage or deployment constraints, the width is constrained by the desired illuminated swath width. As the across-track beam width which sets the swath size is proportional to the wavelength, a fixed swath size equates to a smaller antenna as the frequency is increased. This loss of antenna size reduces the two-way antenna gain to the second power, drastically reducing the signal-to-noise ratio of the SAR system. This fundamental constraint of high-frequency SAR systems is addressed by applying digital beam-forming (DBF) techniques to

  9. The altitude of type 3 auroral irregularities - Radar interferometer observations and implications

    NASA Astrophysics Data System (ADS)

    Sahr, J. D.; Farley, D. T.; Swartz, W. E.; Providakes, J. F.

    1991-10-01

    Altitude measurements are presented of type 3 auroral irregularities, acquired in northern Scandinavia in March 1989 during the second E Region Rocket Radar Instability Study campaign, that provide conclusive arguments against the electrostatic ion cyclotron instability theory. Interferometric analyses of coherent radar observations with a portable radar interferometer show that type 3 events occur at typical electrojet altitudes (100-120 km), at which the ion collision frequency is greater than the ion gyrofrequency, and no cyclotron motion is possible.

  10. Multifrequency, single pass free electron laser

    DOEpatents

    Szoke, Abraham; Prosnitz, Donald

    1985-01-01

    A method for simultaneous amplification of laser beams with a sequence of frequencies in a single pass, using a relativistic beam of electrons grouped in a sequence of energies corresponding to the sequence of laser beam frequencies. The method allows electrons to pass from one potential well or "bucket" to another adjacent bucket, thus increasing efficiency of trapping and energy conversion.

  11. Gadanki Ionospheric Radar Interferometer (GIRI): System Description, Capabilities and Observations

    NASA Astrophysics Data System (ADS)

    Durga rao, Meka; Jayaraman, Achuthan; Patra, Amit; Kamaraj, Pandian; Jayaraj, Katta; Raghavendra, J.; Yasodha, Polisetti

    2016-07-01

    A 30-MHz radar has been developed at National Atmospheric Research Laboratory for dedicated probing of ionosphere and to study the low latitude ionospheric plasma irregularities. The radar has the beam steering capability to scan a larger part of the sky up to ±45o in East-West direction, which will overcome the limitation of slit camera picture obtained by the fixed beam of the Gadanki MST radar on the ionospheric plasma irregularity/structures. The system is also configured for pulse-to-pulse beam steering, employs multi-channel receiving system to carryout Interferometry/Imaging experiments. The radar system employs 20x8 phased antenna array, Direct Digital Synthesizers to generate pulse coded excitation signals, high power solid-state Transmit-Receive modules to generate a peak power of 150 kW, low loss coaxial beam forming and feeder network and multi-channel direct IF digital receiver. Round-the-clock observations are being made with uninterrupted operations and high quality E-and F-Region Range-Time-Intensity and conical maps are obtained with the system. In this paper we present, the system design philosophy, realization, initial observations and also the capability of the system to augment for Meteor observations.

  12. Development of an external interferometer for meteor wind observation attached to the MU radar

    NASA Astrophysics Data System (ADS)

    Nakamura, Takuji; Tsuda, Toshitaka; Tsutsumi, Masaki

    1997-05-01

    An external meteor detection system for the middle and upper atmosphere (MU) radar, Shigaraki, Japan, has been developed in order to monitor the wind velocities at 80-100 km. The characteristics of the MU radar system and the observations are closely inspected, and we design a three-channel interferometer system using three independent single antennas. The data-taking system was carefully designed, considering fast data rate, short interpulse period, wide data bits (19 bit), and fast sampling rate (1 million samples/s), and all the logics are assembled by programmable logic devices. This external interferometer was operated since March 1995 during the Doppler beam swinging observation by the MU radar, and the first results are presented. Meteor echo rate was around 2000/day, 1000 of which were usable for postprocessing, i.e., wind measurement. This echo rate is greater than that of the meteor radar system in Jakarta. Wind velocities were determined with time-height resolutions of 1 hour × 2 km, which showed reasonable agreement with the wind velocities determined from the turbulent echoes in the mesosphere. We present the capability of an external interferometry system attached to the mesosphere-stratosphere-troposphere/stratosphere-troposphere radar as a meteor wind observation system.

  13. The Single Pass Multi-component Harvester

    SciTech Connect

    Reed Hoskinson; John R. Hess

    2004-08-01

    collection must be economically advantageous to the producer. To do all that, a single pass multi-component harvester system is most desirable. Results from our first prototype suggest that current combines probably do adequate threshing and that a separate chassis can be developed that does additional separation and that is economically feasible.

  14. Onboard Interferometric SAR Processor for the Ka-Band Radar Interferometer (KaRIn)

    NASA Technical Reports Server (NTRS)

    Esteban-Fernandez, Daniel; Rodriquez, Ernesto; Peral, Eva; Clark, Duane I.; Wu, Xiaoqing

    2011-01-01

    An interferometric synthetic aperture radar (SAR) onboard processor concept and algorithm has been developed for the Ka-band radar interferometer (KaRIn) instrument on the Surface and Ocean Topography (SWOT) mission. This is a mission- critical subsystem that will perform interferometric SAR processing and multi-look averaging over the oceans to decrease the data rate by three orders of magnitude, and therefore enable the downlink of the radar data to the ground. The onboard processor performs demodulation, range compression, coregistration, and re-sampling, and forms nine azimuth squinted beams. For each of them, an interferogram is generated, including common-band spectral filtering to improve correlation, followed by averaging to the final 1 1-km ground resolution pixel. The onboard processor has been prototyped on a custom FPGA-based cPCI board, which will be part of the radar s digital subsystem. The level of complexity of this technology, dictated by the implementation of interferometric SAR processing at high resolution, the extremely tight level of accuracy required, and its implementation on FPGAs are unprecedented at the time of this reporting for an onboard processor for flight applications.

  15. Terrestrial Radar Interferometer Observations of a Rapid Landslide Over Vegetated Terrain

    NASA Astrophysics Data System (ADS)

    Werner, C. L.; Caduff, R.; Strozzi, T.; Wegmüller, U.

    2013-12-01

    In the Spring of 2013 a landslide in the Hintergraben region of canton Obwalden in Switzerland showed a rapid increase in velocity. Hintergraben, at an elevation of about 900 meters is characterized by meadow and some trees. A region approximately 200 meters wide and 500 meters long was affected. Starting in February, the velocity increased to 30 cm/day by 1-May and continued to accelerate by deceleration to 8 cm/day by 27-May. We report on observations of this landslide using the Gamma Portable Radar Interferometer (GPRI). The GPRI is an FM-CW radar operating at 17.2 GHz (Ku-Band) with an operational range up to 10 km. Range resolution is 90 cm along the LOS. The instrument operates in real-aperture mode with 0.4 degree wide fan-beam giving an azimuth resolution better than 7 meters at 1 kilometer range. During data acquisition, the radar performed an azimuth scan of the scene at a rate of 5 degrees/sec. The radar is phase coherent and capable of acquiring data suitable for differential interferometry with a precision for measuring changes in the LOS distance > 0.1 mm. Limiting factors in the accuracy of LOS motion are interferometric phase coherence and variations in delay due to water vapor. The GPRI was deployed to map ground motion for 2 campaigns on 6 May and 26-27 May 2013. The radar position over 3.5 km from the landslide on the opposite side of Lake Sarnen. Due to rapid temporal decorrelation at Ku-Band data, acquisitions were made at 1 minute intervals. The GPRI deformation maps cover almost the entire region of the active landslide during both observation periods of 6 hours on 6 May and 9 hours on 26-27 May. Measured peak velocities were 35 and 8 cm/day respectively. Point-wise verification of the radar observations was carried out using a Leica TCR803 total station with an estimated accuracy of 1/2 mm at 3.5 km distance. A set of optical corner cubes and radar reflectors were set up in the region of the landslide on 26-May. The radar deformation

  16. Efficient Single-Pass Index Construction for Text Databases.

    ERIC Educational Resources Information Center

    Heinz, Steffen; Zobel, Justin

    2003-01-01

    Discusses index construction for text collections, reviews principal approaches to inverted indexes, analyzes their theoretical cost, and presents experimental results of the use of a single-pass inversion method on Web document collections. Shows that the single-pass approach is faster and does not require the complete vocabulary of the indexed…

  17. Breaking the Contrast Limit in Single-Pass Fabry-Pérot Spectrometers

    NASA Astrophysics Data System (ADS)

    Antonacci, G.; De Panfilis, S.; Di Domenico, G.; DelRe, E.; Ruocco, G.

    2016-11-01

    The development of high-resolution Fabry-Pérot interferometers has enabled a wide range of scientific and technological advances—ranging from the characterization of material properties to the more fundamental studies of quasiparticles in condensed matter. Spectral contrast is key to measuring weak signals and can reach a 103 peak-to-background ratio in a single-pass assembly. At its heart, this limit is a consequence of an unbalanced field amplitude across multiple interfering paths, with an ensuing reduced fringe visibility. Using a high-resolution, high-throughput virtually imaged phased array spectrometer, we demonstrate an intensity-equalization method to achieve an unprecedented 1000-fold increase in spectral contrast in a single-stage, single-pass configuration. To validate the system, we obtain the Brillouin spectrum of water at high scattering concentrations where, unlike with the standard scheme, the inelastic peaks are highly resolved. Our method brings the interferometer close to its ultimate limits and allows rapid high-resolution spectral analysis in a wide range of fields, including Brillouin spectroscopy, mechanical imaging, and molecular fingerprinting.

  18. Thermal efficiency of single-pass solar air collector

    SciTech Connect

    Ibrahim, Zamry; Ibarahim, Zahari; Yatim, Baharudin; Ruslan, Mohd Hafidz

    2013-11-27

    Efficiency of a finned single-pass solar air collector was studied. This paper presents the experimental study to investigate the effect of solar radiation and mass flow rate on efficiency. The fins attached at the back of absorbing plate to improve the thermal efficiency of the system. The results show that the efficiency is increased proportional to solar radiation and mass flow rate. Efficiency of the collector archived steady state when reach to certain value or can be said the maximum performance.

  19. Single-Pass Clustering Algorithm Based on Storm

    NASA Astrophysics Data System (ADS)

    Fang, LI; Longlong, DAI; Zhiying, JIANG; Shunzi, LI

    2017-02-01

    The dramatically increasing volume of data makes the computational complexity of traditional clustering algorithm rise rapidly accordingly, which leads to the longer time. So as to improve the efficiency of the stream data clustering, a distributed real-time clustering algorithm (S-Single-Pass) based on the classic Single-Pass [1] algorithm and Storm [2] computation framework was designed in this paper. By employing this kind of method in the Topic Detection and Tracking (TDT) [3], the real-time performance of topic detection arises effectively. The proposed method splits the clustering process into two parts: one part is to form clusters for the multi-thread parallel clustering, the other part is to merge the generated clusters in the previous process and update the global clusters. Through the experimental results, the conclusion can be drawn that the proposed method have the nearly same clustering accuracy as the traditional Single-Pass algorithm and the clustering accuracy remains steady, computing rate increases linearly when increasing the number of cluster machines and nodes (processing threads).

  20. Comparison of winds measured by MU radar and Fabry-Perot interferometer and effect of OI5577 airglow height variations

    NASA Astrophysics Data System (ADS)

    Fujii, Junsuke; Nakamura, Takuji; Tsuda, Toshitaka; Shiokawa, Kazuo

    2004-04-01

    We have compared wind velocities around mesopause height measured by the middle and upper atmosphere (MU) radar (meteor mode) and OI (5577) airglow observation by an Fabry-Perot Interferometer (FPI), at Shigaraki (34.8°N,136.1°E), Japan, on November 13/14, 1999. When we assume the airglow height is constant throughout the night, it was difficult to find a single height exhibiting small r.m.s. differences between the two methods for both eastward and northward wind velocities. However, in the case we introduce a time variation of the airglow height due to a large-scale gravity wave activity, we have found very small r.m.s. wind difference: The assumptions are of the airglow height variation with an amplitude of 1.5km, a period of 5.7h and a linear trend of -0.19km/h having the average height of 92.8km. Further analysis of time and height variations of the winds and diffusion coefficients measured by the MU radar indicated that a gravity wave with a very similar structure predicted in the above comparison between the FPI and meteor winds has been detected as a dominant wave component. Thus, we conclude that the existence of a gravity wave which can change the airglow height will lead to differences in wind velocities observed with FPI and radar techniques.

  1. Single Pass Streaming BLAST on FPGAs*†

    PubMed Central

    Herbordt, Martin C.; Model, Josh; Sukhwani, Bharat; Gu, Yongfeng; VanCourt, Tom

    2008-01-01

    Approximate string matching is fundamental to bioinformatics and has been the subject of numerous FPGA acceleration studies. We address issues with respect to FPGA implementations of both BLAST- and dynamic-programming- (DP) based methods. Our primary contribution is a new algorithm for emulating the seeding and extension phases of BLAST. This operates in a single pass through a database at streaming rate, and with no preprocessing other than loading the query string. Moreover, it emulates parameters turned to maximum possible sensitivity with no slowdown. While current DP-based methods also operate at streaming rate, generating results can be cumbersome. We address this with a new structure for data extraction. We present results from several implementations showing order of magnitude acceleration over serial reference code. A simple extension assures compatibility with NCBI BLAST. PMID:19081828

  2. Observations of auroral E-region plasma waves and electron heating with EISCAT and a VHF radar interferometer

    NASA Astrophysics Data System (ADS)

    Providakes, J.; Farley, D. T.; Fejer, B. G.; Sahr, J.; Swartz, W. E.

    1988-05-01

    Two radars were used simultaneously to study naturally occurring electron heating events in the auroral E-region ionosphere. During a joint campaign in March 1986 the Cornell University Portable Radar Interferometer (CUPRI) was positioned to look perpendicular to the magnetic field to observe unstable plasma waves over Tromso, Norway, while EISCAT measured the ambient conditions in the unstable region. On two nights EISCAT detected intense but short lived (less than 1 min) electron heating events during which the temperature suddenly increased by a factor of 2-4 at altitudes near 108 km and the electron densities were less than 70,000/cu cm. On the second of these nights CUPRI was operating and detected strong plasma waves with very large phase velocities at precisely the altitudes and times at which the heating was observed. The altitudes, as well as one component of the irregularity drift velocity, were determined by interferometric techniques. From the observations and our analysis, it is concluded that the electron temperature increases were caused by plasma wave heating and not by either Joule heating or particle precipitation.

  3. Comparison of medium frequency pulsed radar interferometer and correlation analysis winds, part 1

    NASA Technical Reports Server (NTRS)

    Meek, C. E.; Reid, I. M.; Manson, A. H.

    1986-01-01

    In principle, the interferometer analysis determines the radial velocity and direction of single scatterers provided that each has a sufficiently different Doppler frequency to permit separation by spectral analysis. In fact, scatterers will not have constant radial velocity, and their Doppler frequencies as well as their directions will be modulated by their horizontal motion. Thus, there is a tradeoff between the poorer resolution but less smeared scatterers on shorter records and the higher resolution (longer) records. Three or more non-collinear scatterers are sufficient to determine the wind. It appears that the velocity found from the combined interferometer peaks agrees well with the apparent velocity from correlation methods, but the true velocity is a factor of 2 smaller. This difference might be resolved by searching for scatters showing regular movement between adjacent records.

  4. Error Analysis for High Resolution Topography with Bi-Static Single-Pass SAR Interferometry

    NASA Technical Reports Server (NTRS)

    Muellerschoen, Ronald J.; Chen, Curtis W.; Hensley, Scott; Rodriguez, Ernesto

    2006-01-01

    We present a flow down error analysis from the radar system to topographic height errors for bi-static single pass SAR interferometry for a satellite tandem pair. Because of orbital dynamics the baseline length and baseline orientation evolve spatially and temporally, the height accuracy of the system is modeled as a function of the spacecraft position and ground location. Vector sensitivity equations of height and the planar error components due to metrology, media effects, and radar system errors are derived and evaluated globally for a baseline mission. Included in the model are terrain effects that contribute to layover and shadow and slope effects on height errors. The analysis also accounts for nonoverlapping spectra and the non-overlapping bandwidth due to differences between the two platforms' viewing geometries. The model is applied to a 514 km altitude 97.4 degree inclination tandem satellite mission with a 300 m baseline separation and X-band SAR. Results from our model indicate that global DTED level 3 can be achieved.

  5. Nonlinear Effects in Single-Pass ICRF Heating

    NASA Technical Reports Server (NTRS)

    Arefiev, A. V.; Breizman, B. N.

    1999-01-01

    The Variable Specific Impulse Magnetoplasma Rocket (VASIMR) concept employs Ion Cyclotron Resonant Frequency (ICRF) heating as the main power deposition mechanism. Since the ions accelerate to the full energy in a single pass through the cyclotron resonance, their response to the RF-field will be essentially nonlinear - hence the motivation to amend the commonly used linear approach to the problem. In a collisionless plasma, the energy gain of an accelerated ion is limited by the time the particle spends at the resonance. This time is affected by: (1) incident flow velocity, (2) longitudinal grad B force, (3) ambipolar electric field, and (4) ponderomotive force of the RF-field. Our analysis shows that the grad B force is the dominant factor at low to moderate levels of RF-power. We present nonlinear scaling for the energy gain and the absorption efficiency with RF-power and plasma parameters. We also demonstrate that the nonlinear regime exhibits a steep decrease in the plasma density at the resonance.

  6. Observations of storm time midlatitude ion-neutral coupling using SuperDARN radars and NATION Fabry-Perot interferometers

    NASA Astrophysics Data System (ADS)

    Joshi, P. P.; H. Baker, J. B.; Ruohoniemi, J. M.; Makela, J. J.; Fisher, D. J.; Harding, B. J.; Frissell, N. A.; Thomas, E. G.

    2015-10-01

    Ion drag is known to play an important role in driving neutral thermosphere circulation at auroral latitudes, especially during the main phase of geomagnetic storms. During the recovery phase, the neutrals are known to drive the ions and generate ionospheric electric fields and currents via the disturbance dynamo mechanism. At midlatitudes, the precise interplay between ions and neutrals is less understood largely because of the paucity of measurements that have been available. In this work, we investigate ion-neutral coupling at middle latitudes using colocated ion drift velocity measurements obtained from Super Dual Auroral Radar Network radars and neutral wind velocity and temperature measurements obtained from the North American Thermosphere Ionosphere Observing Network (NATION) Fabry-Perot interferometers. We examine one recent storm period on 2-3 October 2013 during both the main phase and late recovery phase. By using ion-neutral momentum exchange theory and a time-lagged correlation analysis, we analyze the coupling time scales and dominant driving mechanisms. We observe that during the main phase the neutrals respond to the ion convection on a time scale of ˜84 min which is significantly faster than what would be expected from local ion drag momentum forcing alone. This suggests that other storm time influences are important for driving the neutrals during the main phase, such as Joule heating. During the late recovery phase, the neutrals are observed to drive the ion convection without any significant time delay, consistent with the so-called "neutral fly wheel effect" or disturbance dynamo persisting well into the late recovery phase.

  7. Combined incoherent scatter radar and Fabry-Perot interferometer measurements of frictional heating effects over Millstone Hill during March 7-10, 1989

    SciTech Connect

    Hagan, M.E.; Sipler, D.P. )

    1991-01-01

    The authors introduce a methodology to calculate the effects of frictional heating associated with geomagnetic activity using simultaneous incoherent scatter radar and Fabry-Perot interferometer measurements. Vector measurements of ion drift from radar backscatter and neutral wind from optical shifts in the atomic oxygen red line over Millstone Hill, Massachusetts (43{degree}N) for the nights of March 7-10, 1989 are presented and are characterized by the magnetic storm activity which prevailed. They combine these measurements to calculate differences in the ion and neutral velocity fields which approach 350 m/s during the most geomagnetically active period that they monitored near 01 UT on March 9. This velocity difference results in a 110{degree}K heating of the ion gas at that time.

  8. Global Identification of Protein Post-translational Modifications in a Single-Pass Database Search.

    PubMed

    Shortreed, Michael R; Wenger, Craig D; Frey, Brian L; Sheynkman, Gloria M; Scalf, Mark; Keller, Mark P; Attie, Alan D; Smith, Lloyd M

    2015-11-06

    Bottom-up proteomics database search algorithms used for peptide identification cannot comprehensively identify post-translational modifications (PTMs) in a single-pass because of high false discovery rates (FDRs). A new approach to database searching enables global PTM (G-PTM) identification by exclusively looking for curated PTMs, thereby avoiding the FDR penalty experienced during conventional variable modification searches. We identified over 2200 unique, high-confidence modified peptides comprising 26 different PTM types in a single-pass database search.

  9. Fine resolution topographic mapping of the Jovian moons: a Ka-band high resolution topographic mapping interferometric synthetic aperture radar

    NASA Technical Reports Server (NTRS)

    Madsen, Soren N.; Carsey, Frank D.; Turtle, Elizabeth P.

    2003-01-01

    The topographic data set obtained by MOLA has provided an unprecedented level of information about Mars' geologic features. The proposed flight of JIMO provides an opportunity to accomplish a similar mapping of and comparable scientific discovery for the Jovian moons through us of an interferometric imaging radar analogous to the Shuttle radar that recently generated a new topographic map of Earth. A Ka-band single pass across-track synthetic aperture radar (SAR) interferometer can provide very high resolution surface elevation maps. The concept would use two antennas mounted at the ends of a deployable boom (similar to the Shuttle Radar Topographic Mapper) extended orthogonal to the direction of flight. Assuming an orbit altitude of approximately 100 km and a ground velocity of approximately 1.5 km/sec, horizontal resolutions at the 10 meter level and vertical resolutions at the sub-meter level are possible.

  10. Fine Resolution Topographic Mapping of the Jovian Moons: A Ka-Band High Resolution Topographic Mapping Interferometric Synthetic Aperture Radar

    NASA Technical Reports Server (NTRS)

    Madsen, S. N.; Carsey, F. D.; Turtle, E. P.

    2003-01-01

    The topographic data set obtained by MOLA has provided an unprecedented level of information about Mars' geologic features. The proposed flight of JIMO provides an opportunity to accomplish a similar mapping of and comparable scientific discovery for the Jovian moons through use of an interferometric imaging radar analogous to the Shuttle radar that recently generated a new topographic map of Earth. A Ka-band single pass across-track synthetic aperture radar (SAR) interferometer can provide very high resolution surface elevation maps. The concept would use two antennas mounted at the ends of a deployable boom (similar to the Shuttle Radar Topographic Mapper) extended orthogonal to the direction of flight. Assuming an orbit altitude of approximately 100km and a ground velocity of approximately 1.5 km/sec, horizontal resolutions at the 10 meter level and vertical resolutions at the sub-meter level are possible.

  11. The Shuttle Radar Topography Mission: A Global DEM

    NASA Technical Reports Server (NTRS)

    Farr, Tom G.; Kobrick, Mike

    2000-01-01

    Digital topographic data are critical for a variety of civilian, commercial, and military applications. Scientists use Digital Elevation Models (DEM) to map drainage patterns and ecosystems, and to monitor land surface changes over time. The mountain-building effects of tectonics and the climatic effects of erosion can also be modeled with DEW The data's military applications include mission planning and rehearsal, modeling and simulation. Commercial applications include determining locations for cellular phone towers, enhanced ground proximity warning systems for aircraft, and improved maps for backpackers. The Shuttle Radar Topography Mission (SRTM) (Fig. 1), is a cooperative project between NASA and the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense. The mission is designed to use a single-pass radar interferometer to produce a digital elevation model of the Earth's land surface between about 60 degrees north and south latitude. The DEM will have 30 m pixel spacing and about 15 m vertical errors.

  12. Radars in space

    NASA Technical Reports Server (NTRS)

    Delnore, Victor E.

    1990-01-01

    The capabilities of active microwave devices operating from space (typically, radar, scatterometers, interferometers, and altimeters) are discussed. General radar parameters and basic radar principles are explained. Applications of these parameters and principles are also explained. Trends in space radar technology, and where space radars and active microwave sensors in orbit are going are discussed.

  13. The Shuttle Radar Topography Mission

    NASA Astrophysics Data System (ADS)

    Farr, T. G.; Kobrick, M.

    2001-12-01

    The Shuttle Radar Topography Mission (SRTM), which flew successfully aboard Endeavour in February 2000, is a cooperative project between NASA, the National Imagery and Mapping Agency, and the German and Italian Space Agencies. The mission was designed to use a single-pass radar interferometer to produce a digital elevation model of the Earth's land surface between about 60 degrees north and 56 degrees south latitude. The DEM will have 30 m horizontal resolution and better than 15 m vertical errors. Two ortho-rectified C-band image mosaics are also planned. Data processing will be completed by the end of 2002. SRTM used a modification of the radar instrument that comprised the Spaceborne Radar Laboratory that flew twice on the Shuttle Endeavour in 1994. To collect the interferometric data, a 60 m mast, additional C-band antenna, and improved tracking and navigation devices were added. A second X-band antenna was also added by the German Space Agency, and produced higher resolution topographic measurements in strips nested within the full, C-band coverage. First results indicate that the radars and ancillary instruments worked very well. Data played back to the ground during the flight were processed to DEMs and products released hours after acquisition. An extensive program for calibration and verification of the SRTM data is now underway. When complete later this year, systematic processing of the data will begin, with final products emerging a continent at a time. Products will be transferred to the US Geological Survey's EROS Data Center for civilian archive and distribution. NIMA will handle Department of Defense distribution. * Work performed under contract to NASA.

  14. The Shuttle Radar Topography Mission

    NASA Astrophysics Data System (ADS)

    Farr, T. G.; Kobrick, M.

    2001-05-01

    The Shuttle Radar Topography Mission (SRTM), which flew successfully aboard Endeavour in February 2000, is a cooperative project between NASA and the National Imagery and Mapping Agency (NIMA). The mission was designed to use a single-pass radar interferometer to produce a digital elevation model of the Earth's land surface between about 60 degrees north and 56 degrees south latitude. The DEM will have 30 m horizontal resolution and about 15 m vertical errors. Two ortho-rectified C-band image mosaics are also planned. SRTM used a modification of the radar instrument that comprised the Spaceborne Radar Laboratory that flew twice on the Shuttle Endeavour in 1994. To collect the interferometric data, a 60 m mast, additional C-band antenna, and improved tracking and navigation devices were added. A second X-band antenna was also added by the German Space Agency, and produced higher resolution topographic measurements in strips nested within the full, C-band coverage. First results indicate that the radars and ancillary instruments worked very well. Data played back to the ground during the flight were processed to DEMs and products released hours after acquisition. An extensive program for calibration and verification of the SRTM data is now underway. When complete later this year, systematic processing of the data will begin, with final products emerging a continent at a time. Data processing will be completed by the end of 2002. Products will be transferred to the US Geological Survey's EROS Data Center for civilian archive and distribution. NIMA will handle Department of Defense distribution. * Work performed under contract to NASA.

  15. Evaluating single-pass catch as a tool for identifying spatial pattern in fish distribution

    USGS Publications Warehouse

    Bateman, D.S.; Gresswell, R.E.; Torgersen, C.E.

    2005-01-01

    We evaluate the efficacy of single-pass electrofishing without blocknets as a tool for collecting spatially continuous fish distribution data in headwater streams. We compare spatial patterns in abundance, sampling effort, and length-frequency distributions from single-pass sampling of coastal cutthroat trout (Oncorhynchus clarki clarki) to data obtained from a more precise multiple-pass removal electrofishing method in two mid-sized (500–1000 ha) forested watersheds in western Oregon. Abundance estimates from single- and multiple-pass removal electrofishing were positively correlated in both watersheds, r = 0.99 and 0.86. There were no significant trends in capture probabilities at the watershed scale (P > 0.05). Moreover, among-sample variation in fish abundance was higher than within-sample error in both streams indicating that increased precision of unit-scale abundance estimates would provide less information on patterns of abundance than increasing the fraction of habitat units sampled. In the two watersheds, respectively, single-pass electrofishing captured 78 and 74% of the estimated population of cutthroat trout with 7 and 10% of the effort. At the scale of intermediate-sized watersheds, single-pass electrofishing exhibited a sufficient level of precision to be effective in detecting spatial patterns of cutthroat trout abundance and may be a useful tool for providing the context for investigating fish-habitat relationships at multiple scales.

  16. Aerobic and anaerobic storage of single-pass, chopped corn stover

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn stover has great potential as a biomass feedstock due its widespread availability. However, storage characteristics of moist corn stover harvested from single-pass harvesters have not been well quantified. In 2007, whole-plant corn stover at 19.1 to 40.3 % (w.b.) moisture content was stored fo...

  17. Fuel-element failures in Hanford single-pass reactors 1944--1971

    SciTech Connect

    Gydesen, S.P.

    1993-07-01

    The primary objective of the Hanford Environmental Dose Reconstruction (HEDR) Project is to estimate the radiation dose that individuals could have received as a result of emissions since 1944 from the US Department of Energy`s (DOE) Hanford Site near Richland, Washington. To estimate the doses, the staff of the Source Terms Task use operating information from historical documents to approximate the radioactive emissions. One source of radioactive emissions to the Columbia River came from leaks in the aluminum cladding of the uranium metal fuel elements in single-pass reactors. The purpose of this letter report is to provide photocopies of the documents that recorded these failures. The data from these documents will be used by the Source Terms Task to determine the contribution of single-pass reactor fuel-element failures to the radioactivity of the reactor effluent from 1944 through 1971. Each referenced fuel-element failure occurring in the Hanford single-pass reactors is addressed. The first recorded failure was in 1948, the last in 1970. No records of fuel-element failures were found in documents prior to 1948. Data on the approximately 2000 failures which occurred during the 28 years (1944--1971) of Hanford single-pass reactor operations are provided in this report.

  18. Emittance Reduction between EBIS LINAC and Booster by Electron Beam Cooling; Is Single Pass Cooling Possible?

    SciTech Connect

    Hershcovitch,A.

    2008-04-01

    Electron beam cooling is examined as an option to reduce momentum of gold ions exiting the EBIS LINAC before injection into the booster. Electron beam parameters are based on experimental data (obtained at BNL) of electron beams extracted from a plasma cathode. Preliminary calculations indicate that single pass cooling is feasible; momentum spread can be reduced by more than an order of magnitude in less than one meter.

  19. Self-amplified spontaneous emission for a single pass free-electron laser

    NASA Astrophysics Data System (ADS)

    Giannessi, L.; Alesini, D.; Antici, P.; Bacci, A.; Bellaveglia, M.; Boni, R.; Boscolo, M.; Briquez, F.; Castellano, M.; Catani, L.; Chiadroni, E.; Cianchi, A.; Ciocci, F.; Clozza, A.; Couprie, M. E.; Cultrera, L.; Dattoli, G.; Del Franco, M.; Dipace, A.; di Pirro, G.; Doria, A.; Drago, A.; Fawley, W. M.; Ferrario, M.; Ficcadenti, L.; Filippetto, D.; Frassetto, F.; Freund, H. P.; Fusco, V.; Gallerano, G.; Gallo, A.; Gatti, G.; Ghigo, A.; Giovenale, E.; Marinelli, A.; Labat, M.; Marchetti, B.; Marcus, G.; Marrelli, C.; Mattioli, M.; Migliorati, M.; Moreno, M.; Mostacci, A.; Orlandi, G.; Pace, E.; Palumbo, L.; Petralia, A.; Petrarca, M.; Petrillo, V.; Poletto, L.; Quattromini, M.; Rau, J. V.; Reiche, S.; Ronsivalle, C.; Rosenzweig, J.; Rossi, A. R.; Rossi Albertini, V.; Sabia, E.; Serafini, L.; Serluca, M.; Spassovsky, I.; Spataro, B.; Surrenti, V.; Vaccarezza, C.; Vescovi, M.; Vicario, C.

    2011-06-01

    SPARC (acronym of “Sorgente Pulsata ed Amplificata di Radiazione Coerente”, i.e. Pulsed and Amplified Source of Coherent Radiation) is a single pass free-electron laser designed to obtain high gain amplification at a radiation wavelength of 500 nm. Self-amplified spontaneous emission has been observed driving the amplifier with the high-brightness beam of the SPARC linac. We report measurements of energy, spectra, and exponential gain. Experimental results are compared with simulations from several numerical codes.

  20. Single-pass albumin dialysis in a child aged six months with phenobarbital poisoning.

    PubMed

    Kıhtır, Hasan Serdar; Yıldırım, Hamdi Murat; Yeşilbaş, Osman; Duramaz, Burcu Bursal; Şevketoğlu, Esra

    2016-12-01

    A girl aged six months was hospitalized because of resistant seizures and was discharged with phenobarbital and carbamazepine therapy. She was admitted to a state hospital with symptoms of inability to waken and difficulty in breathing. It was learned that phenobarbital had been used incorrectly and the patient was sent to our pediatric intensive care unit because of severe phenobarbital overdose. The decision was taken for hemodialysis. Single-pass albumin dialysis was planned because phenobarbital can bind to high levels of plasma protein. The process was undertaken with 1% albumin-containing dialysate, which was prepared manually. After 6 hours of dialysis, the phenobarbital blood level measured 62 mcg/mL (>140 mcg/mL on admission) and the patient's clinical findings were markedly regressed. There are no case reports about phenobarbital overdose treated with single-pass albumin dialysis in the literature. We conclude that single-pass albumin dialysis may be a useful treatment, especially with intoxications of drugs that bind protein at high levels.

  1. Single-pass albumin dialysis in a child aged six months with phenobarbital poisoning

    PubMed Central

    Kıhtır, Hasan Serdar; Yıldırım, Hamdi Murat; Yeşilbaş, Osman; Duramaz, Burcu Bursal; Şevketoğlu, Esra

    2016-01-01

    A girl aged six months was hospitalized because of resistant seizures and was discharged with phenobarbital and carbamazepine therapy. She was admitted to a state hospital with symptoms of inability to waken and difficulty in breathing. It was learned that phenobarbital had been used incorrectly and the patient was sent to our pediatric intensive care unit because of severe phenobarbital overdose. The decision was taken for hemodialysis. Single-pass albumin dialysis was planned because phenobarbital can bind to high levels of plasma protein. The process was undertaken with 1% albumin-containing dialysate, which was prepared manually. After 6 hours of dialysis, the phenobarbital blood level measured 62 mcg/mL (>140 mcg/mL on admission) and the patient’s clinical findings were markedly regressed. There are no case reports about phenobarbital overdose treated with single-pass albumin dialysis in the literature. We conclude that single-pass albumin dialysis may be a useful treatment, especially with intoxications of drugs that bind protein at high levels. PMID:28123338

  2. Ground-based portable radar interferometer for imaging glacier flow, ocean-glacier ice interactions, and river ice breakup

    NASA Astrophysics Data System (ADS)

    Fahnestock, M. A.; Cassotto, R.; Truffer, M.

    2013-12-01

    Over the last 18 months we have deployed new 17 GHz imaging radars from Gamma Remote Sensing to document flow on land terminating and tidewater glaciers in Greenland and Alaska; to image glacier response to tides and calving; to track floating ice in fjords; and to document river ice movement, ice jams, and associated flooding during breakup on the Tanana River in Alaska. During these deployments we have learned much about atmospheric influences on interferometric measurements; combination of flow direction determinations from feature tracking in amplitude imagery with short-term flow variability from interferometry. We show examples documenting measurement capabilities and limitations from each of these deployments. These radars represent unique tools for study of rapid changes in dynamic parts of the cryosphere.

  3. Laser doppler and radar interferometer for contactless measurements on unaccessible tie-rods on monumental buildings: Santa Maria della Consolazione Temple in Todi

    NASA Astrophysics Data System (ADS)

    Gioffré, M.; Cavalagli, N.; Pepi, C.; Trequattrini, M.

    2017-01-01

    Non-contact measurements can be effectively used in civil engineering to assess the variation of structural performance with time. In the last decades this approach has received considerable interests from researchers working in the field of structural health monitoring (SHM). Indeed, non-contact measurements are very attractive because it is possible to perform non intrusive and non destructive investigations even being at a significant distance from the targets. Within this context, contactless measurements of the tie-rod vibrations in the Santa Maria della Consolazione Temple in Todi (Italy) are presented in this paper. In particular, laser vibrometer and radar interferometer measurements are used to estimate natural frequencies and mode shapes. This information is crucial to obtain the tensile axial force in the tie-rods, which can be used as an indicator of structural integrity or possible failure. Furthermore, a novel approach is proposed where drones (Unmanned Aerial Vehicles) can be successfully used to improve the effectiveness and the accuracy of the experimental activities.

  4. Assessing the efficacy of single-pass backpack electrofishing to characterize fish community structure

    USGS Publications Warehouse

    Meador, M.R.; McIntyre, J.P.; Pollock, K.H.

    2003-01-01

    Two-pass backpack electrofishing data collected as part of the U.S. Geological Survey's National Water-Quality Assessment Program were analyzed to assess the efficacy of single-pass backpack electrofishing. A two-capture removal model was used to estimate, within 10 river basins across the United States, proportional fish species richness from one-pass electrofishing and probabilities of detection for individual fish species. Mean estimated species richness from first-pass sampling (ps1) ranged from 80.7% to 100% of estimated total species richness for each river basin, based on at least seven samples per basin. However, ps1 values for individual sites ranged from 40% to 100% of estimated total species richness. Additional species unique to the second pass were collected in 50.3% of the samples. Of these, cyprinids and centrarchids were collected most frequently. Proportional fish species richness estimated for the first pass increased significantly with decreasing stream width for 1 of the 10 river basins. When used to calculate probabilities of detection of individual fish species, the removal model failed 48% of the time because the number of individuals of a species was greater in the second pass than in the first pass. Single-pass backpack electrofishing data alone may make it difficult to determine whether characterized fish community structure data are real or spurious. The two-pass removal model can be used to assess the effectiveness of sampling species richness with a single electrofishing pass. However, the two-pass removal model may have limited utility to determine probabilities of detection of individual species and, thus, limit the ability to assess the effectiveness of single-pass sampling to characterize species relative abundances. Multiple-pass (at least three passes) backpack electrofishing at a large number of sites may not be cost-effective as part of a standardized sampling protocol for large-geographic-scale studies. However, multiple

  5. Supersonic COIL driven by centrifugal bubbling SOG with efficient depletion of chemicals in single pass

    NASA Astrophysics Data System (ADS)

    Zagidullin, Marsel V.; Nikolaev, Valery D.; Khvatov, Nikolay A.; Svistun, Michael I.

    2008-10-01

    An efficient and compact centrifugal bubbling SOG was employed as energy source in supersonic COIL. A centrifugal bubbling SOG generated gas at 100 torr of total pressure providing 90% of chlorine utilization and 60% of O2(1Δ) yield with efficient depletion of BHP chemicals in single pass through SOG. A 1 kW class ejector COIL powered by this SOG demonstrated a specific power of 12.5 W per 1cm3/s of BHP volumetric rate at chemical efficiency 22.7%.

  6. KARIN: The Ka-Band Radar Interferometer for the Proposed Surface Water and Ocean Topography (SWOT) Mission

    NASA Technical Reports Server (NTRS)

    Esteban-Fernandez, Daniel; Peral, Eva; McWatters, Dalia; Pollard, Brian; Rodriguez, Ernesto; Hughes, Richard

    2013-01-01

    Over the last two decades, several nadir profiling radar altimeters have provided our first global look at the ocean basin-scale circulation and the ocean mesoscale at wavelengths longer than 100 km. Due to sampling limitations, nadir altimetry is unable to resolve the small wavelength ocean mesoscale and sub-mesoscale that are responsible for the vertical mixing of ocean heat and gases and the dissipation of kinetic energy from large to small scales. The proposed Surface Water and Ocean Topography (SWOT) mission would be a partnership between NASA, CNES (Centre National d'Etudes Spaciales) and the Canadian Space Agency, and would have as one of its main goals the measurement of ocean topography with kilometer-scale spatial resolution and centimeter scale accuracy. In this paper, we provide an overview of all ocean error sources that would contribute to the SWOT mission.

  7. Generic, network schema agnostic sparse tensor factorization for single-pass clustering of heterogeneous information networks.

    PubMed

    Wu, Jibing; Meng, Qinggang; Deng, Su; Huang, Hongbin; Wu, Yahui; Badii, Atta

    2017-01-01

    Heterogeneous information networks (e.g. bibliographic networks and social media networks) that consist of multiple interconnected objects are ubiquitous. Clustering analysis is an effective method to understand the semantic information and interpretable structure of the heterogeneous information networks, and it has attracted the attention of many researchers in recent years. However, most studies assume that heterogeneous information networks usually follow some simple schemas, such as bi-typed networks or star network schema, and they can only cluster one type of object in the network each time. In this paper, a novel clustering framework is proposed based on sparse tensor factorization for heterogeneous information networks, which can cluster multiple types of objects simultaneously in a single pass without any network schema information. The types of objects and the relations between them in the heterogeneous information networks are modeled as a sparse tensor. The clustering issue is modeled as an optimization problem, which is similar to the well-known Tucker decomposition. Then, an Alternating Least Squares (ALS) algorithm and a feasible initialization method are proposed to solve the optimization problem. Based on the tensor factorization, we simultaneously partition different types of objects into different clusters. The experimental results on both synthetic and real-world datasets have demonstrated that our proposed clustering framework, STFClus, can model heterogeneous information networks efficiently and can outperform state-of-the-art clustering algorithms as a generally applicable single-pass clustering method for heterogeneous network which is network schema agnostic.

  8. Generic, network schema agnostic sparse tensor factorization for single-pass clustering of heterogeneous information networks

    PubMed Central

    Meng, Qinggang; Deng, Su; Huang, Hongbin; Wu, Yahui; Badii, Atta

    2017-01-01

    Heterogeneous information networks (e.g. bibliographic networks and social media networks) that consist of multiple interconnected objects are ubiquitous. Clustering analysis is an effective method to understand the semantic information and interpretable structure of the heterogeneous information networks, and it has attracted the attention of many researchers in recent years. However, most studies assume that heterogeneous information networks usually follow some simple schemas, such as bi-typed networks or star network schema, and they can only cluster one type of object in the network each time. In this paper, a novel clustering framework is proposed based on sparse tensor factorization for heterogeneous information networks, which can cluster multiple types of objects simultaneously in a single pass without any network schema information. The types of objects and the relations between them in the heterogeneous information networks are modeled as a sparse tensor. The clustering issue is modeled as an optimization problem, which is similar to the well-known Tucker decomposition. Then, an Alternating Least Squares (ALS) algorithm and a feasible initialization method are proposed to solve the optimization problem. Based on the tensor factorization, we simultaneously partition different types of objects into different clusters. The experimental results on both synthetic and real-world datasets have demonstrated that our proposed clustering framework, STFClus, can model heterogeneous information networks efficiently and can outperform state-of-the-art clustering algorithms as a generally applicable single-pass clustering method for heterogeneous network which is network schema agnostic. PMID:28245222

  9. Observations of single-pass ion cyclotron heating in a trans-sonic flowing plasma

    NASA Astrophysics Data System (ADS)

    Bering, E. A.; Díaz, F. R. Chang; Squire, J. P.; Glover, T. W.; Carter, M. D.; McCaskill, G. E.; Longmier, B. W.; Brukardt, M. S.; Chancery, W. J.; Jacobson, V. T.

    2010-04-01

    The VAriable Specific Impulse Magnetoplasma Rocket (VASIMR®) is a high power electric spacecraft propulsion system, capable of Isp/thrust modulation at constant power [F. R. Chang Díaz et al., Proceedings of the 39th AIAA Aerospace Sciences Meeting and Exhibit, Reno, NV, 8-11 Jan. 2001]. The VASIMR® uses a helicon discharge to generate plasma. This plasma is energized by an rf booster stage that uses left hand polarized slow mode waves launched from the high field side of the ion cyclotron resonance. In the experiments reported in this paper, the booster uses 2-4 MHz waves with up to 50 kW of power. This process is similar to the ion cyclotron heating (ICH) in tokamaks, but in the VASIMR® the ions only pass through the resonance region once. The rapid absorption of ion cyclotron waves has been predicted in recent theoretical studies. These theoretical predictions have been supported with several independent measurements in this paper. The single-pass ICH produced a substantial increase in ion velocity. Pitch angle distribution studies showed that this increase took place in the resonance region where the ion cyclotron frequency was roughly equal to the frequency on the injected rf waves. Downstream of the resonance region the perpendicular velocity boost should be converted to axial flow velocity through the conservation of the first adiabatic invariant as the magnetic field decreases in the exhaust region of the VASIMR®. This paper will review all of the single-pass ICH ion acceleration data obtained using deuterium in the first VASIMR® physics demonstrator machine, the VX-50. During these experiments, the available power to the helicon ionization stage increased from 3 to 20+ kW. The increased plasma density produced increased plasma loading of the ICH coupler. Starting with an initial demonstration of single-pass ion cyclotron acceleration, the experiments demonstrate significant improvements in coupler efficiency and in ion heating efficiency. In

  10. Improved reduced models for single-pass and reflective semiconductor optical amplifiers

    NASA Astrophysics Data System (ADS)

    O Duill, S. P.; Barry, L. P.

    2015-01-01

    We present highly accurate and easy to implement, improved lumped semiconductor optical amplifier (SOA) models for both single-pass and reflective semiconductor optical amplifiers (RSOA). The key feature of the model is the inclusion of the internal losses and we show that a few SOA subdivisions are required to achieve a computational accuracy of <0.12 dB. For the case of RSOAs, we generalize a recently published model to account for the internal losses that are vital to replicate the observed RSOA behavior. The results of the improved reduced RSOA model show large overlap when compared to a full bidirectional travelling wave model for over a 40 dB dynamic range of input powers and a 20 dB dynamic range of reflectivity values. The models would be useful for the rapid system simulation of signals in communication systems, i.e. passive optical networks that employ RSOAs, signal processing using SOAs.

  11. AN EXPERIMENTAL TEST OF SUPERRADIANCE IN A SINGLE PASS SEEDED FEL.

    SciTech Connect

    WATANABE, T.; LIU, D.; MURPHY, J.B.; ROSE, J.; SHAFTAN, T.; TSANG, T.; WANG, X.J.; YU, L.H.

    2005-08-21

    Superradiance and nonlinear evolution of a FEL pulse in a single-pass FEL were experimentally demonstrated at the National Synchrotron Light Source (NSLS) Source Development Laboratory (SDL). The experiment was performed using a 1.5 ps high-brightness electron beam and a 100fs Ti:Sapphire seed laser. The seed laser and electron beam interact in the 10 meter long NISUS undulator with a period of 3.89 cm. The FEL spectrum, energy and pulse length along the undulator were measured. FEL saturation was observed, and gain of more the 200 (relative to seed laser) was measured. Both FEL spectrum widening and pulse length shortening were observed; FEL pulses as short as 65 fs FWHM were measured. The superradiance and nonlinear evolution were also simulated using the numerical code GENESIS1.3 yielding good agreement with the experimental results.

  12. Single pass electron beam cooling of gold ions between EBIS LINAC and booster is theoretically possible!

    SciTech Connect

    Hershcovitch, A.

    2011-01-01

    Electron beam cooling is examined as an option to reduce momentum of gold ions exiting the EBIS LINAC before injection into the booster. Electron beam parameters are based on experimental data (obtained at BNL) of electron beams extracted from a plasma cathode. Many issues, regarding a low energy high current electron beam that is needed for electron beam cooling to reduce momentum of gold ions exiting the EBIS LINAC before injection into the booster, were examined. Computations and some experimental data indicate that none of these issues is a show stopper. Preliminary calculations indicate that single pass cooling is feasible; momentum spread can be reduced by more than an order of magnitude in about one meter. Hence, this option cooling deserves further more serious considerations.

  13. Analysis of thermomechanical states in single-pass GMAW surfaced steel element

    NASA Astrophysics Data System (ADS)

    Winczek, Jerzy; Gawronska, Elzbieta; Murcinkova, Zuzana; Hatala, Michal; Pavlenko, Slavko; Makles, Krzysztof

    2017-03-01

    In the paper the model of temperature field, phase changes and stress states calculation during single-pass arc weld surfacing have been presented. In temperature field solution the temperature changes caused by the heat of weld and by electric arc have been taken into consideration. Kinetics of phase changes during heating is limited by temperature values at the beginning and at the end of austenitic transformation, while progress of phase transformations during cooling has been determined on the basis of time-temperature-transformation (TTT) - welding diagram. The analysis of stress state has been presented for S235 steel flat assuming planar section hypothesis and using integral equations of stress equilibrium. It has enabled a clear interpretation of influence of temperature field and phase transformation on stresses caused by surfacing using Gas Metal Arc Welding (GMAW) method.

  14. A Peltier cooled single pass amplifier for Titanium:Sapphire laser pulses

    NASA Astrophysics Data System (ADS)

    Ozawa, A.; Schneider, W.; Najafi, F.; Hänsch, T. W.; Udem, Th.; Hommelhoff, P.

    2010-05-01

    We report on a Peltier cooled single pass amplifier for high repetition rate Titanium:sapphire laser pulses. Pumped with 14 W and seeded with around 400 mW, the output reaches 1.1 W with good beam quality. This amplifier is very user-friendly, easy to maintain and set up and thus represents a device situated between more complicated liquid-nitrogen cooled amplifiers that can operate at higher pump power, and very simple near to room temperature amplifiers that can only be pumped with less power. In addition, we show the results of a finite element simulation on the temperature distribution in a liquid nitrogen cooled amplifier setup designed for highest output powers.

  15. High-Accuracy Elevation Data at Large Scales from Airborne Single-Pass SAR Interferometry

    NASA Astrophysics Data System (ADS)

    Schumann, Guy; Moller, Delwyn; Mentgen, Felix

    2015-12-01

    Digital elevation models (DEMs) are essential data sets for disaster risk management and humanitarian relief services as well as many environmental process models. At present, on the hand, globally available DEMs only meet the basic requirements and for many services and modeling studies are not of high enough spatial resolution and lack accuracy in the vertical. On the other hand, LiDAR-DEMs are of very high spatial resolution and great vertical accuracy but acquisition operations can be very costly for spatial scales larger than a couple of hundred square km and also have severe limitations in wetland areas and under cloudy and rainy conditions. The ideal situation would thus be to have a DEM technology that allows larger spatial coverage than LiDAR but without compromising resolution and vertical accuracy and still performing under some adverse weather conditions and at a reasonable cost. In this paper, we present a novel single pass In-SAR technology for airborne vehicles that is cost-effective and can generate DEMs with a vertical error of around 0.3 m for an average spatial resolution of 3 m. To demonstrate this capability, we compare a sample single-pass In-SAR Ka-band DEM of the California Central Valley from the NASA/JPL airborne GLISTIN-A to a high-resolution LiDAR DEM. We also perform a simple sensitivity analysis to floodplain inundation. Based on the findings of our analysis, we argue that this type of technology can and should be used to replace large regions of globally available lower resolution DEMs, particularly in coastal, delta and floodplain areas where a high number of assets, habitats and lives are at risk from natural disasters. We conclude with a discussion on requirements, advantages and caveats in terms of instrument and data processing.

  16. Technical Progress Report on Single Pass Flow Through Tests of Ceramic Waste Forms for Plutonium Immobilization

    SciTech Connect

    Zhao, P.; Roberts, S.; Bourcier, W.L.

    2000-12-03

    This report updates work on measurements of the dissolution rates of single-phase and multi-phase ceramic waste forms in flow-through reactors at Lawrence Livermore National Laboratory. Previous results were reported in Bourcier (1999). Two types of tests are in progress: (1) tests of baseline pyrochlore-based multiphase ceramics; and (2) tests of single-phase pyrochlore, zirconolite, and brannerite (the three phases that will contain most of the actinides). Tests of the multi-phase material are all being run at 25 C. The single-phase tests are being run at 25, 50, and 75 C. All tests are being performed at ambient pressure. The as-made bulk compositions of the ceramics are given in Table 1. The single pass flow-through test procedure [Knauss, 1986 No.140] allows the powdered ceramic to react with pH buffer solutions traveling upward vertically through the powder. Gentle rocking during the course of the experiment keeps the powder suspended and avoids clumping, and allows the system to behave as a continuously stirred reactor. For each test, a cell is loaded with approximately one gram of the appropriate size fraction of powdered ceramic and reacted with a buffer solution of the desired pH. The buffer solution compositions are given in Table 2. All the ceramics tested were cold pressed and sintered at 1350 C in air, except brannerite, which was sintered at 1350 C in a CO/CO{sub 2} gas mixture. They were then crushed, sieved, rinsed repeatedly in alcohol and distilled water, and the desired particle size fraction collected for the single pass flow-through tests (SPFT). The surface area of the ceramics measured by BET ranged from 0.1-0.35 m{sup 2}/g. The measured surface area values, average particle size, and sample weights for each ceramic test are given in the Appendices.

  17. An interpretation and guide to single-pass beam shaping methods using SLMs and DMDs

    NASA Astrophysics Data System (ADS)

    Stilgoe, Alexander B.; Kashchuk, Anatolii V.; Preece, Daryl; Rubinsztein-Dunlop, Halina

    2016-06-01

    Exquisite manipulations of light can be performed with devices such as spatial light modulators (SLMs) and digital micromirror devices (DMDs). These devices can be used to simulate transverse paraxial beam wavefunction eigenstates such as the Hermite-Laguerre-Gaussian mode families. We investigate several beam shaping methods in terms of the wavefunctions of scattered light. Our analysis of the efficiency, behaviour and limitations of beam shaping methods is applied to both theory and experiment. The deviation from the ideal output from a valid beam shaping method is shown to be due to experimental factors which are not necessarily being accounted for. Incident beam mode shape, aberration, and the amplitude/phase transfer functions of the DMD and SLM impact the distribution of scattered light and hence the effectiveness and efficiency of a beam shaping method. Correcting for these particular details of the optical system accounts for all differences in efficiency and mode fidelity between experiment and theory. We explicitly show the impact of experimental parameter variations so that these problems may be diagnosed and corrected in an experimental beam shaping apparatus. We show that several beam shaping methods can be used for the production of beam modes in a single pass and the choice is based on the particular experimental conditions.

  18. History of improvements in single-pass ICRH ion acceleration in the VASIMR engine

    NASA Astrophysics Data System (ADS)

    Bering, Edgar; Chang-Diaz, Franklin; Bengtson, Roger D.

    2005-10-01

    The Variable Specific Impulse Magnetoplasma Rocket (VASIMR) is a high power magnetoplasma rocket, capable of Isp/thrust modulation at constant power. The plasma is produced by helicon discharge. The bulk of the energy is added by ion cyclotron resonance heating (ICRH.) Axial momentum is obtained by adiabatic expansion of the plasma in a magnetic nozzle. Thrust/specific impulse ratio control in the VASIMR is primarily achieved by the partitioning of the RF power to the helicon and ICRH systems, with the proper adjustment of the propellant flow. Ion dynamics in the exhaust were studied using probes, gridded energy analyzers (RPA's), microwave interferometry and optical techniques. This paper will review 3 years of single-pass ICRH ion acceleration data. During this interval, the available power to the helicon ionization stage has increased from 3 to 20 kW. The increased plasma density has produced increased plasma loading of the ICRH antenna and isignificant improvements in antenna coupling efficiency and in ion heating efficiency.

  19. Parametric analysis of plastic strain and force distribution in single pass metal spinning

    SciTech Connect

    Choudhary, Shashank E-mail: mohantejesh93@gmail.com E-mail: ksuresh@hyderabad.bits-pilani.ac.in; Tejesh, Chiruvolu Mohan E-mail: mohantejesh93@gmail.com E-mail: ksuresh@hyderabad.bits-pilani.ac.in; Regalla, Srinivasa Prakash E-mail: mohantejesh93@gmail.com E-mail: ksuresh@hyderabad.bits-pilani.ac.in; Suresh, Kurra E-mail: mohantejesh93@gmail.com E-mail: ksuresh@hyderabad.bits-pilani.ac.in

    2013-12-16

    Metal spinning also known as spin forming is one of the sheet metal working processes by which an axis-symmetric part can be formed from a flat sheet metal blank. Parts are produced by pressing a blunt edged tool or roller on to the blank which in turn is mounted on a rotating mandrel. This paper discusses about the setting up a 3-D finite element simulation of single pass metal spinning in LS-Dyna. Four parameters were considered namely blank thickness, roller nose radius, feed ratio and mandrel speed and the variation in forces and plastic strain were analysed using the full-factorial design of experiments (DOE) method of simulation experiments. For some of these DOE runs, physical experiments on extra deep drawing (EDD) sheet metal were carried out using En31 tool on a lathe machine. Simulation results are able to predict the zone of unsafe thinning in the sheet and high forming forces that are hint to the necessity for less-expensive and semi-automated machine tools to help the household and small scale spinning workers widely prevalent in India.

  20. Non-destructive single-pass low-noise detection of ions in a beamline

    SciTech Connect

    Schmidt, Stefan; Murböck, Tobias; Birkl, Gerhard; Andelkovic, Zoran; Vogel, Manuel; Nörtershäuser, Wilfried; Stahl, Stefan

    2015-11-15

    We have conceived, built, and operated a device for the non-destructive single-pass detection of charged particles in a beamline. The detector is based on the non-resonant pick-up and subsequent low-noise amplification of the image charges induced in a cylindrical electrode surrounding the particles’ beam path. The first stage of the amplification electronics is designed to be operated from room temperature down to liquid helium temperature. The device represents a non-destructive charge counter as well as a sensitive timing circuit. We present the concept and design details of the device. We have characterized its performance and show measurements with low-energy highly charged ions (such as Ar{sup 13+}) passing through one of the electrodes of a cylindrical Penning trap. This work demonstrates a novel approach of non-destructive, low noise detection of charged particles which is, depending on the bunch structure, suitable, e.g., for ion traps, low-energy beamlines or accelerator transfer sections.

  1. Non-destructive single-pass low-noise detection of ions in a beamline.

    PubMed

    Schmidt, Stefan; Murböck, Tobias; Andelkovic, Zoran; Birkl, Gerhard; Nörtershäuser, Wilfried; Stahl, Stefan; Vogel, Manuel

    2015-11-01

    We have conceived, built, and operated a device for the non-destructive single-pass detection of charged particles in a beamline. The detector is based on the non-resonant pick-up and subsequent low-noise amplification of the image charges induced in a cylindrical electrode surrounding the particles' beam path. The first stage of the amplification electronics is designed to be operated from room temperature down to liquid helium temperature. The device represents a non-destructive charge counter as well as a sensitive timing circuit. We present the concept and design details of the device. We have characterized its performance and show measurements with low-energy highly charged ions (such as Ar(13+)) passing through one of the electrodes of a cylindrical Penning trap. This work demonstrates a novel approach of non-destructive, low noise detection of charged particles which is, depending on the bunch structure, suitable, e.g., for ion traps, low-energy beamlines or accelerator transfer sections.

  2. Augmented Binary Substitution: Single-pass CDR germ-lining and stabilization of therapeutic antibodies

    PubMed Central

    Townsend, Sue; Fennell, Brian J.; Apgar, James R.; Lambert, Matthew; McDonnell, Barry; Grant, Joanne; Wade, Jason; Franklin, Edward; Foy, Niall; Ní Shúilleabháin, Deirdre; Fields, Conor; Darmanin-Sheehan, Alfredo; King, Amy; Paulsen, Janet E.; Tchistiakova, Lioudmila; Cunningham, Orla; Finlay, William J. J.

    2015-01-01

    Although humanized antibodies have been highly successful in the clinic, all current humanization techniques have potential limitations, such as: reliance on rodent hosts, immunogenicity due to high non-germ-line amino acid content, v-domain destabilization, expression and formulation issues. This study presents a technology that generates stable, soluble, ultrahumanized antibodies via single-step complementarity-determining region (CDR) germ-lining. For three antibodies from three separate key immune host species, binary substitution CDR cassettes were inserted into preferred human frameworks to form libraries in which only the parental or human germ-line destination residue was encoded at each position. The CDR-H3 in each case was also augmented with 1 ± 1 random substitution per clone. Each library was then screened for clones with restored antigen binding capacity. Lead ultrahumanized clones demonstrated high stability, with affinity and specificity equivalent to, or better than, the parental IgG. Critically, this was mainly achieved on germ-line frameworks by simultaneously subtracting up to 19 redundant non-germ-line residues in the CDRs. This process significantly lowered non-germ-line sequence content, minimized immunogenicity risk in the final molecules and provided a heat map for the essential non-germ-line CDR residue content of each antibody. The ABS technology therefore fully optimizes the clinical potential of antibodies from rodents and alternative immune hosts, rendering them indistinguishable from fully human in a simple, single-pass process. PMID:26621728

  3. Intestinal permeability of forskolin by in situ single pass perfusion in rats.

    PubMed

    Liu, Zhen-Jun; Jiang, Dong-bo; Tian, Lu-Lu; Yin, Jia-Jun; Huang, Jian-Ming; Weng, Wei-Yu

    2012-05-01

    The intestinal permeability of forskolin was investigated using a single pass intestinal perfusion (SPIP) technique in rats. SPIP was performed in different intestinal segments (duodenum, jejunum, ileum, and colon) with three concentrations of forskolin (11.90, 29.75, and 59.90 µg/mL). The investigations of adsorption and stability were performed to ensure that the disappearance of forskolin from the perfusate was due to intestinal absorption. The results of the SPIP study indicated that forskolin could be absorbed in all segments of the intestine. The effective permeability (P (eff)) of forskolin was in the range of drugs with high intestinal permeability. The P (eff) was highest in the duodenum as compared to other intestinal segments. The decreases of P (eff) in the duodenum and ileum at the highest forskolin concentration suggested a saturable transport process. The addition of verapamil, a P-glycoprotein inhibitor, significantly enhanced the permeability of forskolin across the rat jejunum. The absorbed fraction of dissolved forskolin after oral administration in humans was estimated to be 100 % calculated from rat P (eff). In conclusion, dissolved forskolin can be absorbed readily in the intestine. The low aqueous solubility of forskolin might be a crucial factor for its poor oral bioavailability.

  4. Membranome: a database for proteome-wide analysis of single-pass membrane proteins

    PubMed Central

    Lomize, Andrei L.; Lomize, Mikhail A.; Krolicki, Shean R.; Pogozheva, Irina D.

    2017-01-01

    The Membranome database was developed to assist analysis and computational modeling of single-pass (bitopic) transmembrane (TM) proteins and their complexes by providing structural information about these proteins on a genomic scale. The database currently collects data on >6000 bitopic proteins from Homo sapiens, Arabidopsis thaliana, Dictyostelium discoideum, Saccharomyces cerevisiae, Escherichia coli and Methanocaldococcus jannaschii. It presents the following data: (i) hierarchical classification of bitopic proteins into 15 functional classes, 689 structural superfamilies and 1404 families; (ii) 446 complexes of bitopic proteins with known three-dimensional (3D) structures classified into 129 families; (iii) computationally generated three-dimensional models of TM α-helices positioned in membranes; (iv) amino acid sequences, domain architecture, functional annotation and available experimental structures of bitopic proteins; (v) TM topology and intracellular localization, (vi) physical interactions between proteins from the database along with links to other resources. The database is freely accessible at http://membranome.org. There is a variety of options for browsing, sorting, searching and retrieval of the content, including downloadable coordinate files of TM domains with calculated membrane boundaries. PMID:27510400

  5. Three-color entanglement generated by single-pass cascaded sum-frequency processes

    NASA Astrophysics Data System (ADS)

    Yu, Youbin; Ji, Fengmin; Shi, Zhongtao; Wang, HuaiJun; Zhao, Junwei; Wang, Yajuan

    2017-03-01

    Three-color continuous-variable (CV) entangled beams can be produced by single-pass cascaded sum-frequency processes of third-harmonic generation by quasi-phase-matching technique in only one optical superlattice. Firstly, second-harmonic field is generated by the first double-frequency process of the fundamental field. Then, the third-harmonic field can be generated by the second cascaded sum-frequency process between the second-harmonic and the fundamental fields by quasi-phase-matching technique in the same optical superlattice. By using the quantum stochastic method, we investigated the conversion dynamics of the cascaded sum-frequency processes and the quantum correlation nature among the fundamental, second-harmonic, and third-harmonic fields. The results show that the higher conversion efficiency of third-harmonic generation can be achieved with the larger nonlinear coupling parameter of the second cascaded sum-frequency process. We also show that the fundamental, second-, and third-harmonic beams are CV entangled with each other according to the necessary and sufficient CV entanglement criterion. This scheme of three-color entanglement generation without involving optical cavity is easy to realize in experiment. Moreover, the three-color entangled beams are separated by an octave in frequency which has potential applications in quantum communication and computation networks.

  6. Multifunctional metal-polymer nanoagglomerates from single-pass aerosol self-assembly

    NASA Astrophysics Data System (ADS)

    Byeon, Jeong Hoon

    2016-08-01

    In this study, gold (Au)-iron (Fe) nanoagglomerates were capped by a polymer mixture (PM) consisting of poly(lactide-co-glycolic acid), protamine sulfate, and poly-l-lysine via floating self-assembly in a single-pass aerosol configuration as multibiofunctional nanoplatforms. The Au-Fe nanoagglomerates were directly injected into PM droplets (PM dissolved in dichloromethane) in a collison atomizer and subsequently heat-treated to liberate the solvent from the droplets, resulting in the formation of PM-capped Au-Fe nanoagglomerates. Measured in vitro, the cytotoxicities of the nanoagglomerates (>98.5% cell viability) showed no significant differences compared with PM particles alone (>98.8%), thus implying that the nanoagglomerates are suitable for further testing of biofunctionalities. Measurements of gene delivery performance revealed that the incorporation of the Au-Fe nanoagglomerates enhanced the gene delivery performance (3.2 × 106 RLU mg‑1) of the PM particles alone (2.1 × 106 RLU mg‑1), which may have been caused by the PM structural change from a spherical to a hairy structure (i.e., the change followed the agglomerated backbone). Combining the X-ray-absorbing ability of Au and the magnetic property of Fe led to magnetic resonance (MR)-computed tomography (CT) contrast ability in a phantom; and the signal intensities [which reached 64 s‑1 T2-relaxation in MR and 194 Hounsfield units (HUs) in CT at 6.0 mg mL‑1] depended on particle concentration (0.5–6.0 mg mL‑1).

  7. Multifunctional metal-polymer nanoagglomerates from single-pass aerosol self-assembly

    PubMed Central

    Byeon, Jeong Hoon

    2016-01-01

    In this study, gold (Au)-iron (Fe) nanoagglomerates were capped by a polymer mixture (PM) consisting of poly(lactide-co-glycolic acid), protamine sulfate, and poly-l-lysine via floating self-assembly in a single-pass aerosol configuration as multibiofunctional nanoplatforms. The Au-Fe nanoagglomerates were directly injected into PM droplets (PM dissolved in dichloromethane) in a collison atomizer and subsequently heat-treated to liberate the solvent from the droplets, resulting in the formation of PM-capped Au-Fe nanoagglomerates. Measured in vitro, the cytotoxicities of the nanoagglomerates (>98.5% cell viability) showed no significant differences compared with PM particles alone (>98.8%), thus implying that the nanoagglomerates are suitable for further testing of biofunctionalities. Measurements of gene delivery performance revealed that the incorporation of the Au-Fe nanoagglomerates enhanced the gene delivery performance (3.2 × 106 RLU mg−1) of the PM particles alone (2.1 × 106 RLU mg−1), which may have been caused by the PM structural change from a spherical to a hairy structure (i.e., the change followed the agglomerated backbone). Combining the X-ray-absorbing ability of Au and the magnetic property of Fe led to magnetic resonance (MR)-computed tomography (CT) contrast ability in a phantom; and the signal intensities [which reached 64 s−1 T2-relaxation in MR and 194 Hounsfield units (HUs) in CT at 6.0 mg mL−1] depended on particle concentration (0.5–6.0 mg mL−1). PMID:27507668

  8. Interaction between propranolol and amino acids in the single-pass isolated, perfused rat liver.

    PubMed

    Semple, H A; Xia, F

    1995-08-01

    Propranolol (PL) bioavailability has been shown to increase substantially when it is administered with a protein-rich meal. A change in metabolic capacity or tissue uptake, induced by amino acids (AAs) released as a result of digestion of dietary protein, is a possible contributing mechanism to the food effect. This hypothesis was tested in isolated, perfused rat livers in the single-pass mode. Rac-PL (20 micrograms/ml) was infused to steady-state at 3 ml/min/g liver for 150 min. A balanced mixture of I-AA was coinfused from 70 to 110 min. The AA reversibly increased the steady-state concentration of PL by 18% and reduced steady-state concentrations of 4-hydroxypropranolol, N-deisopropylpranolol, PL glycol, naphthoxylactic acid, and naphthoxyacetic acid by an average of 41% and propanolol conjugates by almost 100%, indicating metabolic inhibition. In a second experiment, PL was coinfused with AAs from the beginning of the experiment, and tissue binding was compared with control livers. There was no significant effect of AAs on PL tissue binding. In a third study, the effect of four different concentrations of AAs coinfused from 70 to 110 min was assessed. The percentage change in PL and phase I metabolite levels was linearly correlated to the influent AA concentration. The large magnitude, reversibility, lack of pathway specificity, and concentration dependence of the AA interaction in the perfused liver are also features of food interaction in humans. These similarities constitute evidence that metabolic inhibition by AAs originating from dietary protein could contribute to the PL-food interaction.

  9. Part II/Addendum Electron Beam Cooling between EBIS LINAC and Booster; Is Single Pass Cooling Possible?

    SciTech Connect

    Hershcovitch,A.

    2008-07-01

    Due to some miscommunication, incomplete data was erroneously used in examining electron beam cooling for reducing momentum of gold ions exiting the EBIS LINAC before injection into the booster. Corrected calculations still indicate that single pass cooling is, in principle, feasible; momentum spread can be reduced by an order of magnitude in about one meter. Preliminary results suggest that this cooling deserves further consideration.

  10. The Malus Fabry-Perot interferometer

    NASA Astrophysics Data System (ADS)

    Vallet, M.; Bretenaker, F.; Le Floch, A.; Le Naour, R.; Oger, M.

    1999-09-01

    We describe a general model for the behaviour of a sensor based on a Fabry-Perot interferometer placed between crossed polarizers. Compared to single-pass polarimeters, the sensitivity for the measurement of intracavity anisotropies is shown to be enhanced by a factor of the order of the square of the finesse compared to single-pass polarimeters. Our model, based on a vectorial spatial description of the cavity, predicts the response of the system to circular and/or linear intracavity anisotropies. It also gives the ultimate sensitivity and takes into account the spurious backgrounds. Experimental illustrations are presented for different types of reciprocal and non-reciprocal anisotropies. Moreover, it is shown that the insertion of an optical bias combined with a modulation of the intracavity anisotropies leads to experimental sensitivities limited only by the shot noise level, in agreement with theoretical predictions. We discuss further improvements and potential applications for the polarimeter.

  11. Single-Pass Flow Through (SPFT) Testing of Fluidized-Bed Steam Reforming (FBSR) Waste Forms

    SciTech Connect

    Lorier, T. H.; Pareizs, J. M.; Jantzen, C. M.

    2005-08-15

    Two samples of fluidized-bed steam reforming (FBSR) mineral waste form product were subjected to single-pass flow-through (SPFT) testing. Sample LAW 1123 resulted from pilot-scale FBSR processing with a Hanford Envelope A low-activity waste (LAW) simulant. Sample SBW 1173 resulted from pilot-scale FBSR processing with an Idaho National Laboratory (INL) simulant commonly referred to as sodium-bearing waste (SBW). The pilot-scale waste forms were made at the Science and Technology Applications Research (STAR) facility in Idaho Falls, Idaho. The durability of the two FBSR waste forms was assessed via the SPFT test in this study. Both samples were multiphase mineral waste forms, so the SPFT test results provide an overall release rate from the multiple mineral species in each sample and are dependent on the amount of each phase present and the mineralogy of the phases present. SPFT testing was performed at temperatures of 25, 40, 70, and 90 C on LAW 1123, while SBW 1173 was only tested at 70 and 90 C. The 70 and 90 C data were compared to each other and the LAW-1123 results were compared to previous testing performed by the Pacific Northwest National Laboratory (PNNL) on a LAW Envelope C (high organic content) waste simulant. The objectives of this study were to obtain forward dissolution rate data for both STAR FBSR bed products (using SPFT tests). Also, a qualitative comparison of the FBSR bed products to a glass waste form (specifically the low-activity reference material (LRM) glass) was performed. For these comparisons, the relative surface areas of the FBSR and glass products had to be measured. Due to the more porous and irregular surface of FBSR bed products, the surface area of the bed products was determined using the Brunauer, Emmett, and Teller (BET) measurement method. The surface area of a glass is much smoother and the calculated geometric surface area is typically used for determining dissolution behavior. Presently there are no specifications or

  12. The Study of Single-Pass GMA Welds with Different Cover Gas Compositions on HSLA-100 Steel

    DTIC Science & Technology

    1993-09-23

    steels contributes to better weldability, lowers the susceptibility to hydrogen cracking and lower ductile to brittle transition temperature ( DBTT ...COMPOSITIONS ON HSLA-100 STEEL by Ricky Arthur Seraiva September, 1993 Thesis Advisor: Alan G. Fox Approved for public release; distribution is unlimited...TITLE AND SUBTITLE THE STUDY OF SINGLE-PASS GMA 5. FUNDING NUMBERS WELDS WITH DIFFERENT COVER GAS COMPOSITIONS ON HSLA-1O0 STEEL 6. AUTHOR(S) Ricky

  13. Analysis of Microstructure Refinement During Single-Pass and Multi-Pass Friction Stir Processing of Nial Propeller Bronze

    DTIC Science & Technology

    2010-09-01

    on an Optical Micrograph of the Transverse View of Single-Pass NAB. After [5]............................................... 6 Figure 4 . Vertical...deformed and 6 elongated but does not see the same refinement that is seen inside the SZ [ 4 ]. The grain structure right outside the TMAZ will also...including grinding, polishing, and electropolishing . The first step was to grind the surface using a Buehler ECOMET 4 Variable Speed Grinder

  14. Experimental validation of single pass ion cyclotron resonance absorption in a high speed flowing plasma applied to the variable specific impulse magnetoplasma rocket (VASIMR)

    NASA Astrophysics Data System (ADS)

    Davis, Christopher Nelson

    The topic of this thesis is the experimental characterization and analysis of single pass ion cyclotron resonance heating as applied to acceleration of ions for electric propulsion. The experimental work was done on the VX-10 experiment of the VASIMR (Variable Specific Impulse Magnetoplasma Rocket) concept. In ion cyclotron resonance heating (ICRH) a RF wave is launched into a magnetized plasma where it then accelerates the ions by increasing their rotational speed around the magnetic field lines. The electric field vector of the right hand component of the wave will rotate around the field lines with a frequency oRF in the same direction as the ion's cyclotron motion about the field lines. Consequently, when oRF ≈ oci (where oci is the ion's cyclotron frequency) the force from the electric field of the wave on the ions will result in a continuous rotational energy gain. The perpendicular velocity of the ions generated by ICRH is then converted into axial velocity by the decreasing gradient of the axial magnetic field at the exhaust of the propulsion system from conservation of the magnet moment. This increase in axial velocity is predicted to cause a decrease in density due to conservation of current in the plasma. In order to characterize this density drop during ion cyclotron heating, a single channel interferometer system was developed and implemented on the VX-10. Interferometer density measurements were taken at three different locations on the VX-10 experiment upstream and downstream of the ion acceleration zone. Measurements were made of the density drop in both Helium and Deuterium plasma discharges during ICRH under a variety of operating conditions including magnetic field profile, gas flow rate and ICRH power pulse timing, and ICRH power. A clear measurement of a density drop was observed downstream of the ion resonance zone characteristic of ion acceleration and measurement of little change in density upstream of the resonance zone where no

  15. Keck Interferometer

    NASA Technical Reports Server (NTRS)

    2003-01-01

    At the summit of Mauna Kea, Hawaii, NASA astronomers have linked the two 10-meter (33-foot) telescopes at the W. M. Keck Observatory. The linked telescopes, which together are called the Keck Interferometer, make up the world's most powerful optical telescope system. The Keck Interferometer will search for planets around nearby stars and study dust clouds around those stars that may hamper future space-based searches for habitable, Earthlike planets. The Keck Interferometer is part of NASA's Origins program, which seeks to answer two fundamental questions: How did we get here? Are we alone?

  16. UV x-ray free electron lasers through high-gain single pass amplifier: Basic principles and issues

    SciTech Connect

    Kim, K.J.

    1994-09-01

    The author reviews the basic principles of high gain free electron laser amplifier in single pass configuration for generation of intense, tunable radiation for wavelength shorter than 1,000 {angstrom}. Two schemes are discussed: for wavelength region between 1,000--100 {angstrom}, the high gain harmonic generation of a coherent input radiation can be used. For x-ray wavelength as short as a few {angstrom}, the self-amplified spontaneous emission is currently the only known free electron laser scheme. The author also presents a brief introduction of various key issues in realizing these schemes, which will be discussed in detail in other papers in these proceedings.

  17. Birefringent-multicrystal, single-pass, continuous-wave second-harmonic-generation in deep-ultraviolet

    NASA Astrophysics Data System (ADS)

    Devi, Kavita; Parsa, S.; Ebrahim-Zadeh, M.

    2016-04-01

    We report implementation of compact cascaded multicrystal scheme for single-pass second-harmonic-generation (SHG), using birefringent crystal, for continuous-wave (cw) deep ultraviolet (UV) generation. The system comprises of 4 cascaded stages, is based on critical phase-matched interaction in β-BaB2O4 (BBO), and pumped by a cw singlefrequency green source at 532 nm. A deep-UV cw output power of 37.7 mW at 266 nm has been obtained with a high passive power stability of 0.12 % rms over more than 4 hours in Gaussian spatial beam quality with a circularity of >70%.

  18. A bounding estimate of neutron dose based on measured photon dose around single pass reactors at the Hanford site.

    PubMed

    Taulbee, Timothy D; Glover, Samuel E; Macievic, Gregory V; Hunacek, Mickey; Smith, Cheryl; DeBord, Gary W; Morris, Donald; Fix, Jack

    2010-07-01

    Neutron and photon radiation survey records have been used to evaluate and develop a neutron to photon (NP) ratio to reconstruct neutron doses to workers around Hanford's single pass reactors that operated from 1945 to 1972. A total of 5,773 paired neutron and photon measurements extracted from 57 boxes of survey records were used in the development of the NP ratio. The development of the NP ratio enables the use of the recorded dose from an individual's photon dosimeter badge to be used to estimate the unmonitored neutron dose. The Pearson rank correlation between the neutron and photon measurements was 0.71. The NP ratio best fit a lognormal distribution with a geometric mean (GM) of 0.8, a geometric standard deviation (GSD) of 2.95, and the upper 95 th % of this distribution was 4.75. An estimate of the neutron dose based on this NP ratio is considered bounding due to evidence that up to 70% of the total photon exposure received by workers around the single pass reactors occurs during shutdown maintenance and refueling activities when there is no significant neutron exposure. Thus when this NP ratio is applied to the total measured photon dose from an individual film badge dosimeter, the resulting neutron dose is considered bounded.

  19. Application of a portable radar interferometer and terrestrial long-range lidar for high resolution data acquisition of natural rock slopes

    NASA Astrophysics Data System (ADS)

    Kos, Andrew; Strozzi, Tazio; Tomkinson, William; Conforti, Dario; Wiesmann, Andreas

    2010-05-01

    The application of portable radar interferometry using real aperture technology, integrated with long range terrestrial lidar for monitoring unstable rock slopes will be presented. Measurement precision as well as spatial and temporal resolution of the combined methods will be discussed in terms of selected case studies. The advantages of system portability and method of data acquisition will be highlighted since field inaccessibility often hinders the placement of instruments for optimal lines-of-site or range for the acquisition of high resolution data.

  20. Lucretia: A Matlab-Based Toolbox for the Modellingand Simulation of Single-Pass Electron Beam Transport Systems

    SciTech Connect

    Tenenbaum, P.; /SLAC

    2005-09-30

    We report on Lucretia, a new simulation tool for the study of single-pass electron beam transport systems. Lucretia supports a combination of analytic and tracking techniques to model the tuning and operation of bunch compressors, linear accelerators, and beam delivery systems of linear colliders and linac-driven Free Electron Laser (FEL) facilities. Extensive use of Matlab scripting, graphics, and numerical capabilities maximize the flexibility of the system, and emphasis has been placed on representing and preserving the fixed relationships between elements (common girders, power supplies, etc.) which must be respected in the design of tuning algorithms. An overview of the code organization, some simple examples, and plans for future development are discussed.

  1. Modification of continuous venovenous hemodiafiltration with single-pass albumin dialysate allows for removal of serum bilirubin.

    PubMed

    Chawla, Lakhmir S; Georgescu, Florin; Abell, Bruce; Seneff, Michael G; Kimmel, Paul L

    2005-03-01

    A 53-year-old woman was admitted to the hospital with ischemic colitis and underwent a subtotal colectomy. She developed acute renal failure, severe hyperbilirubinemia, and intense pruritus resistant to medical treatment. Extracorporeal albumin dialysis using a Molecular Adsorbent Recirculating System (MARS; Gambro Co, Lund, Sweden) has been used to treat liver failure and reduce total serum bilirubin (SB) levels. A trial of extracorporeal albumin dialysis with continuous renal replacement therapy (RRT) was instituted to achieve net removal of SB. A 25% albumin solution was mixed with conventional dialysate to yield a dialysate concentration of 1.85% or 5.0% albumin. The patient underwent 2 continuous RRT sessions using extracorporeal albumin dialysis (1.85% and 5.0% albumin dialysate). Pretreatment and posttreatment SB levels were determined, and total bilirubin concentration (TB) also was measured in each of the collection bags during conventional and albumin dialysis. Pretreatment and posttreatment SB levels were 50.4 mg/dL (862 micromol/L) and 39.0 mg/dL (667 micromol/L) with 1.85% albumin dialysate and 47.1 mg/dL (805 micromol/L) and 39.7 mg/dL (679 micromol/L) with 5.0% albumin dialysate, respectively. The collected dialysate TB level was 0.3 mg/dL (5 micromol/L) during nonalbumin RRT and increased to 1.37 +/- 0.06 mg/dL (23 +/- 1 micromol/L) with 1.85% albumin dialysis. The collected dialysate fluid TB level was 0.3 mg/dL (5 micromol/L) during the nonalbumin RRT and increased to 1.38 +/- 0.15 mg/dL (24 +/- 3 micromol/L) during 5.0% albumin RRT. Single-pass albumin dialysis with continuous RRT cleared SB better than standard continuous RRT. Single-pass albumin dialysis with continuous RRT is feasible and may be a viable alternative in centers that do not have access to MARS therapy. This modality merits additional evaluation for its efficacy in clearing albumin-bound serum toxins.

  2. The Shuttle Radar Topography Mission: Introduction to Special Session

    NASA Astrophysics Data System (ADS)

    Farr, T. G.; Werner, M.; Kobrick, M.

    2003-04-01

    The Shuttle Radar Topography Mission (SRTM), which flew successfully aboard Endeavour in February 2000, is a cooperative project between NASA, the National Imagery and Mapping Agency, and the German and Italian Space Agencies. The mission was designed to use a single-pass radar interferometer to produce a digital elevation model of the Earth's land surface between about 60^o north and 56^o south latitude. The DEM has 30 m horizontal resolution and better than 15 m vertical errors. Two ortho-rectified C-band image mosaics are also produced. SRTM used a modification of the radar instrument that comprised the Spaceborne Radar Laboratory that flew twice on the Shuttle Endeavour in 1994. To collect the interferometric data, a 60 m mast, additional C-band antenna, and improved tracking and navigation devices were added. A second X-band antenna was also added by the German Space Agency, and produced higher resolution topographic measurements in strips nested within the full, C-band coverage. First results indicate that the radars and ancillary instruments worked very well. Data played back to the ground during the flight were processed to DEMs and preliminary products released hours after acquisition. Precision processing of the C-band data was completed at the end of 2002. An extensive program for calibration and verification of the SRTM data is now underway. Data have been released so far for the US and a few test areas for scientific analysis. Public release of the data will occur in stages throughout 2003. Products are being transferred to the US Geological Survey's EROS Data Center for civilian archive and distribution. NIMA will handle Department of Defense distribution. X-band data are being processed at the German and Italian Space Agencies. As of late 2002, Europe and Africa had been completed and the remaining continents were on schedule to be completed by the end of 2003. This special session will highlight applications of this new high-resolution view of the

  3. Evaluation of the single-pass flow-through test to support a low-activity waste specification

    SciTech Connect

    McGrail, B.P.; Peeler, D.K.

    1995-09-01

    A series of single-pass flow-through (SPFT) tests was performed on five reference low-activity waste glasses and a reference glass from the National Institute of Standards and Technology to support a product specification for low-activity waste (LAW) forms. The results showed that the SPFT test provides a means to quantitatively distinguish among LAW glass forms in terms of their forward reaction rate at a given temperature and solution pH. Two of the test glasses were also subjected to SPFT testing at Argonne National Laboratory (ANL). Forward reaction rate constants calculated from the ANL test data were 100 to over 1,000 times larger than the values obtained from the SPFT tests conducted at PNL. An analysis of the ANL results showed that they were inconsistent with independent measurements done on glasses of similar composition, the known pH-dependence of the forward rate, and with the results from low surface-area-to-volume, short duration product consistency tests. Because the data set obtained from the SPFT tests done at PNL was consistent with each of these same factors, a detailed examination of the test procedures used at both laboratories was performed to determine the cause(s) of the discrepancy. The omission of background subtraction in the data analysis procedure and the short-duration (on the order of hours) of the ANL tests are factors that may have significantly affected the calculated rates.

  4. {open_quotes}Optical guiding{close_quotes} limits on extraction efficiencies of single-pass, tapered wiggler amplifiers

    SciTech Connect

    Fawley, W.M.

    1995-12-31

    Single-pass, tapered wiggler amplifiers have an attractive feature of being able, in theory at least, of extracting a large portion of the electron beam energy into light. In circumstances where an optical FEL`s wiggler length is significantly longer than the Rayleigh length Z{sub R} corresponding to the electron beam radius, diffraction losses must be controlled via the phenomenon of {open_quotes}optical guiding{close_quotes}. Since the strength of the guiding depends upon the effective refractive index {eta}{sub r} exceeding one, and since ({eta}{sub r}-1) is inversely proportional to the optical electric field, there is a natural {open_quotes}limiting{close_quotes} mechanism to the on-axis field strength and thus the rate at which energy may be extracted from the electron beam. In particular, the extraction efficiency for a prebunched beam asymptotically grows linearly with z rather than quadratically. We present analytical and numerical simulation results concerning this behavior and discuss its applicability to various FEL designs including oscillator/amplifier-radiator configurations.

  5. Single-Pass Percutaneous Liver Biopsy for Diffuse Liver Disease Using an Automated Device: Experience in 154 Procedures

    SciTech Connect

    Rivera-Sanfeliz, Gerant Kinney, Thomas B.; Rose, Steven C.; Agha, Ayad K.M.; Valji, Karim; Miller, Franklin J.; Roberts, Anne C.

    2005-06-15

    Purpose: To describe our experience with ultrasound (US)-guided percutaneous liver biopsies using the INRAD 18G Express core needle biopsy system.Methods: One hundred and fifty-four consecutive percutaneous core liver biopsy procedures were performed in 153 men in a single institution over 37 months. The medical charts, pathology reports, and radiology files were retrospectively reviewed. The number of needle passes, type of guidance, change in hematocrit level, and adequacy of specimens for histologic analysis were evaluated.Results: All biopsies were performed for histologic staging of chronic liver diseases. The majority of patients had hepatitis C (134/153, 90.2%). All patients were discharged to home after 4 hr of postprocedural observation. In 145 of 154 (94%) biopsies, a single needle pass was sufficient for diagnosis. US guidance was utilized in all but one of the procedures (153/154, 99.4%). The mean hematocrit decrease was 1.2% (44.1-42.9%). Pain requiring narcotic analgesia, the most frequent complication, occurred in 28 of 154 procedures (18.2%). No major complications occurred. The specimens were diagnostic in 152 of 154 procedures (98.7%).Conclusions: Single-pass percutaneous US-guided liver biopsy with the INRAD 18G Express core needle biopsy system is safe and provides definitive pathologic diagnosis of chronic liver disease. It can be performed on an outpatient basis. Routine post-biopsy monitoring of hematocrit level in stable, asymptomatic patients is probably not warranted.

  6. Intestinal absorptive transport of Genkwanin from Flos genkwa using a single-pass intestinal perfusion rat model.

    PubMed

    Jiang, Cui-Ping; He, Xin; Yang, Xiao-Lin; Zhang, Su-Li; Li, Hui; Song, Zi-Jing; Zhang, Chun-Feng; Yang, Zhong-Lin; Li, Ping

    2014-01-01

    To investigate the absorptive transport behavior of genkwanin and the beneficial effects of monoterpene enhancers with different functional groups, the single-pass intestinal perfusion (SPIP) of rats was used. The results showed that genkwanin was segmentally-dependent and the best absorptive site was the duodenum. The effective permeability coefficient (P eff ) was 1.97 × 10(-4) cm/s and the absorption rate constant (Ka) was 0.62 × 10(-2) s(-1). Transepithelial transportation descended with increasing concentrations of genkwanin. This was a 1.4-fold increase in P eff by probenecid, whereas a 1.4-fold or 1.6-fold decrease was observed by verapamil and pantoprazole, respectively. Furthermore, among the absorption enhancers, the enhancement with carbonyl (camphor and menthone) was higher than that with hydroxyl (borneol and menthol). The concentration-independent permeability and enhancement by coperfusion of probenecid indicated that genkwanin was transported by both passive diffusion and multidrug resistance protein (MDR)-mediated efflux mechanisms.

  7. Immiscible phase nucleic acid purification eliminates PCR inhibitors with a single pass of paramagnetic particles through a hydrophobic liquid.

    PubMed

    Sur, Kunal; McFall, Sally M; Yeh, Emilie T; Jangam, Sujit R; Hayden, Mark A; Stroupe, Stephen D; Kelso, David M

    2010-09-01

    Extraction and purification of nucleic acids from complex biological samples for PCR are critical steps because inhibitors must be removed that can affect reaction efficiency and the accuracy of results. This preanalytical processing generally involves capturing nucleic acids on microparticles that are then washed with a series of buffers to desorb and dilute out interfering substances. We have developed a novel purification method that replaces multiple wash steps with a single pass of paramagnetic particles (PMPs) though an immiscible hydrophobic liquid. Only two aqueous solutions are required: a lysis buffer, in which nucleic acids are captured on PMPs, and an elution buffer, in which they are released for amplification. The PMPs containing the nucleic acids are magnetically transported through a channel containing liquid wax that connects the lysis chamber to the elution chamber in a specially designed cartridge. Transporting PMPs through the immiscible phase yielded DNA and RNA as pure as that obtained after extensive wash steps required by comparable purification methods. Our immiscible-phase process has been applied to targets in whole blood, plasma, and urine and will enable the development of faster and simpler purification systems.

  8. Merits of a sub-harmonic approach to a single-pass, 1.5-{Angstrom} FEL

    SciTech Connect

    Fawley, W.M.; Nuhn, H.D.; Bonifacio, R.; Scharlemann, E.T.

    1995-03-01

    SLAC/SSRL and collaborators elsewhere are studying th physics of a single-pass, FEL amplifier operating in th 1 -- 2 {Angstrom}, wavelength region based on electron beams from the SLAC linac at {approximately} 15 GeV energy. Hoping to reduce the total wiggler length needed to reach saturation when starting from shot noise, we have examined the benefits of making the first part of the wiggler resonant at a subharmonic wavelength (e.g. 4.5 {Angstrom}) at which the gain length can be significantly shorter. This leads to bunching of the electron beam at both the subharmonic and fundaments wavelengths, thus providing a strong coherent ``seed`` for exponential growth of radiation at the fundamental in the second part of the wiggler. Using both multi-harmonic and multi-frequency 2D FEL simulation codes, we have examined the predicted performance of such devices and the sensitivity to electron beam parameters such as current, emittance, and instantaneous energy spread.

  9. Using a Ground Based radar interferometer during emergency: the case of A3 motorway (Salerno Reggio-Calabria) treated by landslide

    NASA Astrophysics Data System (ADS)

    Del Ventisette, Chiara; Intrieri, Emanuele; Luzi, Guido; Casagli, Nicola

    2010-05-01

    An application of Ground Based radar interferometry (GB-InSAR) technique to monitor a landslide threatening infrastructures in emergency conditions is presented. During December 2008 and January 2009 intense rainfalls occurred in Italy, especially in the southern regions. These rain events occurred in the last days of January, worsened the already critical hydrogeological conditions of some areas and triggered many landslides. One of these landslides, named Santa Trada landslide, is located close to a periodical stream called Fiumara di Santa Trada, near Villa San Giovanni municipality (Reggio Calabria, Calabria Region). The volume involved is about 100 000 m3. This estimate represents the case of a collapse of the landslide which destabilize a larger part of the slope, involving other areas delimited by some fractures observed upstream. Nevertheless the landslide does not directly threaten the roadway, its complete collapse would hit the pillars of a motorway viaduct. Through GB-InSAR data it has been possible to obtain an overview of the area affected by movement and to quantify the displacements magnitude. The main benefit of the system was not only limited to the capability of fully characterizing the landslide in spatial terms, it also permitted emergency operators to follow, during the whole campaign, the evolution of the mass movement and to study its cinematic behaviour. This aspect is fundamental to evaluate the volume of the material involved and to assess the temporal evolution of the risk scenario. The GB-InSAR installed at Santa Trada points up toward the landslide from a distance of 250 m. The apparatus produces a synthesized radar image of the observed area every 6 minutes, night and day, with a pixel resolution of about 0.75 m in range and 1.2 m on average in cross range, performing a millimeter accuracy on the final displacement maps. The interferometric analysis of sequences of consecutive images allows the operator to derive the entire line of

  10. Split-Bolus Single-Pass Multidetector-Row CT Protocol for Diagnosis of Acute Pulmonary Embolism

    PubMed Central

    Scialpi, Michele; Rebonato, Alberto; Cagini, Lucio; Brunese, Luca; Piscioli, Irene; Pierotti, Luisa; Bellantonio, Lucio; D’Andrea, Alfredo; Rotondo, Antonio

    2016-01-01

    Background: Currently computed tomography pulmonary angiography (CTPA) has become a widely accepted clinical tool in the diagnosis of acute pulmonary embolism (PE). Objectives: To report split-bolus single-pass 64-multidetector-row CT (MDCT) protocol for diagnosis of PE. Patients and Methods: MDCT split-bolus results in 40 patients suspicious of PE were analyzed in terms of image quality of target pulmonary vessels (TPVs) and occurrence and severity of flow-related artifact, flow-related artifact, false filling defect of the pulmonary veins and beam hardening streak artifacts. Dose radiation to patients was calculated. Results: MDCT split-bolus protocol allowed diagnostic images of high quality in all cases. Diagnosis of PE was obtained in 22 of 40 patients. Mean attenuation for target vessels was higher than 250 HU all cases: 361 ± 98 HU in pulmonary artery trunk (PAT); 339 ± 93 HU in right pulmonary artery (RPA); 334 ± 100 HU in left pulmonary artery (LPA). Adequate enhancement was obtained in the right atrium (RA):292 ± 83 HU; right pulmonary vein (RPV): 302 ± 91 HU, and left pulmonary vein (LPV): 291 ± 83 HU. The flow related artifacts and the beam hardening streak artifacts have been detected respectively in 4 and 25 patients. No false filling defect of the pulmonary veins was revealed. Conclusion: MDCT split-bolus technique by simultaneous opacification of pulmonary arteries and veins represents an accurate technique for diagnosis of acute PE, removes the false filling defects of the pulmonary veins, and reduces flow related artifacts. PMID:27110334

  11. In-situ single pass intestinal permeability and pharmacokinetic study of developed Lumefantrine loaded solid lipid nanoparticles.

    PubMed

    Garg, Anuj; Bhalala, Kripal; Tomar, Devendra Singh; Wahajuddin

    2017-01-10

    The present investigation aims to develop lumefantrine loaded binary solid lipid nanoparticles (LF-SLNs) to improve its poor and variable oral bioavailability. The oral bioavailability of LF is poor and variable due to its limited aqueous solubility and P-gp mediated efflux occurring in small intestine. LF-SLNs were prepared using binary lipid mixture of stearic acid and caprylic acid stabilized with TPGS (D-alpha tocopheryl polyethylene glycol 1000 succinate) and Poloxamer 188. Developed LF-SLNs were characterized for particle size distribution, zeta potential, entrapment efficiency, solid state properties and biopharmaceutical properties including in situ intestinal permeability and oral bioavailability. The particle size distribution, zeta potential and entrapment efficiency of optimized batch (LF-SLN7) was found to be 357.7±43.27nm, 25.29±1.15mV and 97.35±0.30%, respectively. DSC thermographs showed loss of crystalline nature of lumefantrine in LF-SLNs. In situ single pass intestinal permeability study (SPIP) study indicated significant enhancement in the effective intestinal permeability of LF from LF-SLN7 as compared to that of control. Pharmacokinetic study also showed significant increase in Cmax and area under curve (AUC0-∞) from LF-SLN7 (3860±521ng/mL and 43181±2557h×ng/mL, respectively) as compared to that of LF-control suspension (1425±563ng/mL and 19586±1537h×ng/mL, respectively). Thus, developed LF-SLNs can be promising to overcome P-gp efflux pump and enhance the oral bioavailability of lumefantrine.

  12. Michelson Interferometer

    NASA Technical Reports Server (NTRS)

    Rogers, Ryan

    2007-01-01

    The Michelson Interferometer is a device used in many applications, but here it was used to measure small differences in distance, in the milli-inch range, specifically for defects in the Orbiter windows. In this paper, the method of using the Michelson Interferometer for measuring small distances is explained as well as the mathematics of the system. The coherence length of several light sources was calculated in order to see just how small a defect could be measured. Since white light is a very broadband source, its coherence length is very short and thus can be used to measure small defects in glass. After finding the front and back reflections from a very thin glass slide with ease and calculating the thickness of it very accurately, it was concluded that this system could find and measure small defects on the Orbiter windows. This report also discusses a failed attempt for another use of this technology as well as describes an area of promise for further analysis. The latter of these areas has applications for finding possible defects in Orbiter windows without moving parts.

  13. Special relativity and interferometers

    NASA Technical Reports Server (NTRS)

    Han, D.; Kim, Y. S.

    1988-01-01

    A new generation of gravitational wave detectors is expected to be based on interferometers. Yurke et al. (1986) introduced a class of interferometers characterized by SU(1,1) which can in principle achieve a phase sensitivity approaching 1/N, where N is thte total number of photons entering the interferometer. It is shown here that the SU(1,1) interferometer can serve as an analog computer for Wigner's little group of the Poincare\\'| group.

  14. Sodium D2 resonance radiation in single-pass sum-frequency generation with actively mode-locked Nd:YAG lasers

    NASA Astrophysics Data System (ADS)

    Saito, Norihito; Akagawa, Kazuyuki; Ito, Mayumi; Takazawa, Akira; Hayano, Yutaka; Saito, Yoshihiko; Ito, Meguru; Takami, Hideki; Iye, Masanori; Wada, Satoshi

    2007-07-01

    We report on a sodium D2 resonance coherent light source achieved in single-pass sum-frequency generation in periodically poled MgO-doped stoichiometric lithium tantalate with actively mode-locked Nd:YAG lasers. Mode-locked pulses at 1064 and 1319 nm are synchronized with a time resolution of 37 ps with the phase adjustment of the radio frequencies fed to acousto-optic mode lockers. An output power of 4.6 W at 589.1586 nm is obtained, and beam quality near the diffraction limit is also achieved in a simple design.

  15. Sodium D2 resonance radiation in single-pass sum-frequency generation with actively mode-locked Nd:YAG lasers.

    PubMed

    Saito, Norihito; Akagawa, Kazuyuki; Ito, Mayumi; Takazawa, Akira; Hayano, Yutaka; Saito, Yoshihiko; Ito, Meguru; Takami, Hideki; Iye, Masanori; Wada, Satoshi

    2007-07-15

    We report on a sodium D(2) resonance coherent light source achieved in single-pass sum-frequency generation in periodically poled MgO-doped stoichiometric lithium tantalate with actively mode-locked Nd:YAG lasers. Mode-locked pulses at 1064 and 1319 nm are synchronized with a time resolution of 37 ps with the phase adjustment of the radio frequencies fed to acousto-optic mode lockers. An output power of 4.6 W at 589.1586 nm is obtained, and beam quality near the diffraction limit is also achieved in a simple design.

  16. 1.5 W green light generation by single-pass second harmonic generation of a single-frequency tapered diode laser.

    PubMed

    Jensen, Ole Bjarlin; Andersen, Peter E; Sumpf, Bernd; Hasler, Karl-Heinz; Erbert, Götz; Petersen, Paul Michael

    2009-04-13

    More than 1.5 W of green light at 531 nm is generated by single-pass second harmonic generation in periodically poled MgO:LiNbO3. The pump laser is a high power tapered laser with a distributed Bragg reflector etched in the ridge section of the laser to provide wavelength selectivity. The output power of the single-frequency tapered laser is 9.3 W in continuous wave operation. A conversion efficiency of 18.5 % was achieved in the experiments.

  17. A time-resolved single-pass technique for measuring optical absorption coefficients of window materials under 100 GPa shock pressures.

    PubMed

    Li, Jun; Zhou, Xianming; Li, Jiabo

    2008-12-01

    An experimental method was developed to perform time-resolved, single-pass optical absorption measurements and to determine absorption coefficients of window materials under strong shock compression up to approximately 200 GPa. Experimental details are described of (i) a configuration to generate an in situ dynamic, bright, optical source and (ii) a sample assembly with a lithium fluoride plate to essentially eliminate heat transfer from the hot radiator into the specimen and to maintain a constant optical source within the duration of the experiment. Examples of measurements of optical absorption coefficients of several initially transparent single crystal materials at high shock pressures are presented.

  18. 1.2 MW peak power, all-solid-state picosecond laser with a microchip laser seed and a high gain single-passing bounce geometry amplifier

    NASA Astrophysics Data System (ADS)

    Wang, Chunhua; Shen, Lifeng; Zhao, Zhiliang; Liu, Bin; Jiang, Hongbo; Chen, Jun; Liu, Chong

    2016-11-01

    A semiconductor saturable absorber mirror (SESAM) based passively Q-switched microchip Nd:YVO4 seed laser with pulse duration of 90 ps at repetition rate of 100 kHz is amplified by single-passing a Nd:YVO4 bounce amplifier with varying seed input power from 20 μW to 10 mW. The liquid pure metal greasy thermally conductive material is used to replace the traditional thin indium foil as the thermal contact material for better heat load transfer of the Nd:YVO4 bounce amplifier. Temperature distribution at the pump surface is measured by an infrared imager to compare with the numerically simulated results. A highest single-passing output power of 11.3 W is obtained for 10 mW averaged seed power, achieving a pulse peak power of ~1.25 MW and pulse energy of ~113 μJ. The beam quality is well preserved with M2 ≤1.25. The simple configuration of this bounce laser amplifier made the system flexible, robust and cost-effective, showing attractive potential for further applications.

  19. Simultaneous determination of nine model compounds in permeability samples using RP-HPLC: application to prove the cassette administration principle in single pass intestinal perfusion study in rats.

    PubMed

    Wahajuddin; Singh, Sheelendra Pratap; Raju, K S R; Nafis, Asad; Jain, Girish Kumar

    2012-01-01

    A simple, sensitive and specific reversed phase high performance liquid chromatographic (RP-HPLC) method for simultaneous determination of atenolol, paracetamol, hydrochlorothiazide, caffeine, cephalexin, metoprolol, propranolol, ketoprofen along with phenol red (a non-absorbable compound) in samples obtained from intestinal in situ single-pass perfusion studies, was developed and validated. Chromatography was carried out on RP18 column with mobile phase comprising of 10 mM phosphate buffer (pH 2.5) and methanol in gradient mode. The calibration curves were linear for all nine permeability model compounds (r² > 0.999) across the concentration range of 1.25-40 μg/ml. The coefficient of variation for intra and inter-day assay precision was between 0.04 and 3.08% and the accuracy was between 98.39 and 109.45%. Stability studies were carried out at different storage conditions and all the analytes were found to be stable. The method was successfully applied for analysing the permeability samples obtained from in situ single pass perfusion studies. The effective permeability (P(eff)) values obtained upon cassette administration were in close proximity to the permeability values obtained upon single administration of model compounds. In conclusion, the developed RP-HPLC method can be used for high throughput cassette validation of rat in situ perfusion model for intestinal permeability assessment.

  20. Lens collimation and testing using a Twyman-Green interferometer with a self-pumped phase-conjugating mirror

    NASA Technical Reports Server (NTRS)

    Howes, W. L.

    1986-01-01

    Ordinarily Twyman-Green interferometers are employed testing optical elements. In a modification of the basic configuration, the ordinary mirror in the test arm is replaced with a self-pumped phase-conjugating mirror using a barium titanate crystal. It is shown that, with a redefinition of components, the new configuration permits retention and improvement of the optical element testing function while simultaneously serving as a sensitive test for collimation. The optical path difference resulting from the double pass in the original Twyman-Green interferometer approximately equals that of the single pass and phase conjugation in the modification.

  1. Combined Twyman-Green and Mach-Zehnder interferometer for microlens testing

    SciTech Connect

    Reichelt, Stephan; Zappe, Hans

    2005-09-20

    A new interferometer design for microlens testing is presented. The phase-shifting system combines the advantages of a Twyman-Green and a Mach-Zehnder interferometer and permits full characterization of the aberrations of microlenses as well as radius of curvature and focal length measurements. The Twyman-Green system is applied to surface testing in reflection (single reflection), whereas the Mach-Zehnder system is used for lens testing in transmission (single pass). Both measurements are performed without removal of the test part, allowing for combination of the results without confusion of the actual lens and without an azimuthal orientation error. The interferometer setup is explained, the test procedure is described, and experimental results are given.

  2. Combined Twyman-Green and Mach-Zehnder interferometer for microlens testing.

    PubMed

    Reichelt, Stephan; Zappe, Hans

    2005-09-20

    A new interferometer design for microlens testing is presented. The phase-shifting system combines the advantages of a Twyman-Green and a Mach-Zehnder interferometer and permits full characterization of the aberrations of microlenses as well as radius of curvature and focal length measurements. The Twyman-Green system is applied to surface testing in reflection (single reflection), whereas the Mach-Zehnder system is used for lens testing in transmission (single pass). Both measurements are performed without removal of the test part, allowing for combination of the results without confusion of the actual lens and without an azimuthal orientation error. The interferometer setup is explained, the test procedure is described, and experimental results are given.

  3. Phase shifting interferometer

    DOEpatents

    Sommargren, Gary E.

    1999-01-01

    An interferometer which has the capability of measuring optical elements and systems with an accuracy of .lambda./1000 where .lambda. is the wavelength of visible light. Whereas current interferometers employ a reference surface, which inherently limits the accuracy of the measurement to about .lambda./50, this interferometer uses an essentially perfect spherical reference wavefront generated by the fundamental process of diffraction. Whereas current interferometers illuminate the optic to be tested with an aberrated wavefront which also limits the accuracy of the measurement, this interferometer uses an essentially perfect spherical measurement wavefront generated by the fundamental process of diffraction. This interferometer is adjustable to give unity fringe visibility, which maximizes the signal-to-noise, and has the means to introduce a controlled prescribed relative phase shift between the reference wavefront and the wavefront from the optics under test, which permits analysis of the interference fringe pattern using standard phase extraction algorithms.

  4. Phase shifting interferometer

    DOEpatents

    Sommargren, G.E.

    1999-08-03

    An interferometer is disclosed which has the capability of measuring optical elements and systems with an accuracy of {lambda}/1000 where {lambda} is the wavelength of visible light. Whereas current interferometers employ a reference surface, which inherently limits the accuracy of the measurement to about {lambda}/50, this interferometer uses an essentially perfect spherical reference wavefront generated by the fundamental process of diffraction. Whereas current interferometers illuminate the optic to be tested with an aberrated wavefront which also limits the accuracy of the measurement, this interferometer uses an essentially perfect spherical measurement wavefront generated by the fundamental process of diffraction. This interferometer is adjustable to give unity fringe visibility, which maximizes the signal-to-noise, and has the means to introduce a controlled prescribed relative phase shift between the reference wavefront and the wavefront from the optics under test, which permits analysis of the interference fringe pattern using standard phase extraction algorithms. 11 figs.

  5. Forest Height and Ground Topography at L-Band from an Experimental Single-Pass Airborne Pol-InSAR System

    NASA Astrophysics Data System (ADS)

    Mercer, B.; Zhang, Q.; Schwaebisch, M.; Denbina, M.; Cloude, S.

    2009-04-01

    Many applications require bare-earth Digital Terrain Models (DTMs) in the presence of forest canopy. L-Band is an attractive candidate, but the derived interferometric phase represents a combination of ground and volume scattering contributions from the canopy above. The use of PolInSAR techniques, and the Random Volume Over Ground (RVOG) Model has had considerable success in model inversion studies where the objective has been to extract tree height. A major problem for the robust application of this technique is the presence of temporal decorrelation, caused by the use of repeat-pass interferometry. In this paper we will present the current results of canopy height and DTM estimation in forested areas using an experimental airborne, single-pass, L-Band PolInSAR system for which temporal decorrelation is not an issue.

  6. High-power, high-repetition-rate performance characteristics of β-BaB₂O₄ for single-pass picosecond ultraviolet generation at 266 nm.

    PubMed

    Kumar, S Chaitanya; Casals, J Canals; Wei, Junxiong; Ebrahim-Zadeh, M

    2015-10-19

    We report a systematic study on the performance characteristics of a high-power, high-repetition-rate, picosecond ultraviolet (UV) source at 266 nm based on β-BaB2O4 (BBO). The source, based on single-pass fourth harmonic generation (FHG) of a compact Yb-fiber laser in a two-crystal spatial walk-off compensation scheme, generates up to 2.9 W of average power at 266 nm at a pulse repetition rate of ~80 MHz with a single-pass FHG efficiency of 35% from the green to UV. Detrimental issues such as thermal effects have been studied and confirmed by performing relevant measurements. Angular and temperature acceptance bandwidths in BBO for FHG to 266 nm are experimentally determined, indicating that the effective interaction length is limited by spatial walk-off and thermal gradients under high-power operation. The origin of dynamic color center formation due to two-photon absorption in BBO is investigated by measurements of intensity-dependent transmission at 266 nm. Using a suitable theoretical model, two-photon absorption coefficients as well as the color center densities have been estimated at different temperatures. The measurements show that the two-photon absorption coefficient in BBO at 266 nm is ~3.5 times lower at 200°C compared to that at room temperature. The long-term power stability as well as beam pointing stability is analyzed at different output power levels and focusing conditions. Using cylindrical optics, we have circularized the generated elliptic UV beam to a circularity of >90%. To our knowledge, this is the first time such high average powers and temperature-dependent two-photon absorption measurements at 266 nm are reported at repetition rates as high as ~80 MHz.

  7. Evaluation of a potential generator-produced PET tracer for cerebral perfusion imaging: single-pass cerebral extraction measurements and imaging with radiolabeled Cu-PTSM.

    PubMed

    Mathias, C J; Welch, M J; Raichle, M E; Mintun, M A; Lich, L L; McGuire, A H; Zinn, K R; John, E K; Green, M A

    1990-03-01

    Copper(II) pyruvaldehyde bis(N4-methylthiosemicarbazone) (Cu-PTSM), copper(II) pyruvaldehyde bis(N4-dimethylthiosemicarbazone) (Cu-PTSM2), and copper(II) ethylglyoxal bis(N4-methylthiosemicarbazone) (Cu-ETSM), have been proposed as PET tracers for cerebral blood flow (CBF) when labeled with generator-produced 62Cu (t1/2 = 9.7 min). To evaluate the potential of Cu-PTSM for CBF PET studies, baboon single-pass cerebral extraction measurements and PET imaging were carried out with the use of 67Cu (t1/2 = 2.6 days) and 64Cu (t1/2 = 12.7 hr), respectively. All three chelates were extracted into the brain with high efficiency. There was some clearance of all chelates in the 10-50-sec time frame and Cu-PTSM2 continued to clear. Cu-PTSM and Cu-ETSM have high residual brain activity. PET imaging of baboon brain was carried out with the use of [64Cu]-Cu-PTSM. For comparison with the 64Cu brain image, a CBF (15O-labeled water) image (40 sec) was first obtained. Qualitatively, the H2(15)O and [64Cu]-Cu-PTSM images were very similar; for example, a comparison of gray to white matter uptake resulted in ratios of 2.42 for H2(15)O and 2.67 for Cu-PTSM. No redistribution of 64Cu was observed in 2 hr of imaging, as was predicted from the single-pass study results. Quantitative determination of blood flow using Cu-PTSM showed good agreement with blood flow determined with H2(15)O. This data suggests that [62Cu]-Cu-PTSM may be a useful generator-produced radiopharmaceutical for blood flow studies with PET.

  8. Femtosecond plasmon interferometer

    NASA Astrophysics Data System (ADS)

    Melentiev, Pavel N.; Kuzin, Artur A.; Gritchenko, Anton S.; Kalmykov, Alexey S.; Balykin, Victor I.

    2017-01-01

    We have realized a plasmonic interferometer formed by a nanoslit and a nanogroove in a single-crystal gold film. The possibility of measuring laser pulses of ultimately short durations, corresponding to two periods of a light wave (6 fs pulse duration), has been demonstrated using this interferometer.

  9. A laser unequal path interferometer for the optical shop.

    PubMed

    Houston, J B; Buccini, C J; O'Neill, P K

    1967-07-01

    The application of laser technology has been extended to optical shop testing by incorporating a cw, helium-neon gas laser in a package that houses a modified Twyman-Green interferometer. This modification provides for optical testing over large path differences with an auxiliary set of lenses used in the long path and a small reference flat used in the short path of the interferometer. With this technique, f/0.7 spherical mirrors have been tested (at the center of curvature) to an accuracy of 1/10 wavelength at the surface, and various other optical systems have been tested in both double pass and single pass. Two of the advantages of this testing method are (1) the capability of testing spherical concave surfaces without physically contacting the surface and (2) the ability to use small reference surfaces for large optical components or systems. The device known as a laser unequal path interferometer can be used with a set of null lenses to qualify aspheric surfaces. The unit is portable and capable of testing in any orientation under various environmental conditions. Several applications of this device are presented to illustrate its versatility.

  10. Line-shape studies for single- and triple-pass Fabry-Perot interferometer systems.

    PubMed

    Palik, E D; Boukari, H; Gammon, R W

    1995-01-01

    To test the model developed in the preceding paper [Appl. Opt. 34, this issue (1994)] regarding the line shape produced by a Fabry-Perot interferometer system in a multipass mode, we have used three Lorentzian line shapes formed in scattering processes and subjected them to single and triple passes with some variation in the pinhole diameter. In most cases we find good agreement with the calculations with the only adjustable parameter being the single-pass contrast C(1). Where differences occur, plausible explanations are offered.

  11. Geophysical Fiber Interferometer Gyroscope.

    DTIC Science & Technology

    1979-12-31

    gravitational antenna. Basically, their device was a Twyman -Green laser interferometer that was allegedly well-isolated from its thermal and...r ~AD-AO92 913 UTAH UNIV RESEARCH INST SALT LAKE CITY GEOSPACE SCIE-EYC F/B 20/6 GEOPHYSICAL FIBER INTERFEROMETER GYROSCOPE(U) .S DEC 79 L 0 WEAVER...ACCESSION no: S, 111CIPIENT’S CATALOG NUMBER AF6ii M_ __ _ __I_ _ 4. TItLIL (eovm4jk"IU .TYEo nPaTawn.ocoet GEOPHYSICAL FIBER INTERFEROMETER GYROSCOPE. / 9

  12. Sub-Aperture Interferometers

    NASA Technical Reports Server (NTRS)

    Zhao, Feng

    2010-01-01

    Sub-aperture interferometers -- also called wavefront-split interferometers -- have been developed for simultaneously measuring displacements of multiple targets. The terms "sub-aperture" and "wavefront-split" signify that the original measurement light beam in an interferometer is split into multiple sub-beams derived from non-overlapping portions of the original measurement-beam aperture. Each measurement sub-beam is aimed at a retroreflector mounted on one of the targets. The splitting of the measurement beam is accomplished by use of truncated mirrors and masks, as shown in the example below

  13. Nonlinearity-reduced interferometer

    NASA Astrophysics Data System (ADS)

    Wu, Chien-ming

    2007-12-01

    Periodic nonlinearity is a systematic error limiting the accuracy of displacement measurements at the nanometer level. It results from many causes such as the frequency mixing, polarization mixing, polarization-frequency mixing, and the ghost reflections. An interferometer having accuracy in displacement measurement of less than one-nanometer is necessary in nanometrology. To meet the requirement, the periodic nonlinearity should be less than deep sub-nanometer. In this paper, a nonlinearity-reduced interferometry has been proposed. Both the linear- and straightness-interferometer were tested. The developed interferometer demonstrated of a residual nonlinearity less than 25 pm.

  14. Radar principles

    NASA Technical Reports Server (NTRS)

    Sato, Toru

    1989-01-01

    Discussed here is a kind of radar called atmospheric radar, which has as its target clear air echoes from the earth's atmosphere produced by fluctuations of the atmospheric index of refraction. Topics reviewed include the vertical structure of the atmosphere, the radio refractive index and its fluctuations, the radar equation (a relation between transmitted and received power), radar equations for distributed targets and spectral echoes, near field correction, pulsed waveforms, the Doppler principle, and velocity field measurements.

  15. Fizeau plasma interferometer

    SciTech Connect

    Frank, A.M.

    1980-01-01

    This paper describes a technique by which the sensitivity of plasma interferometers can be increased. Stabilization and fractional fringe measurement techniques have improved to the point where additional optical sensitivity could be useful. (MOW)

  16. Dual surface interferometer

    DOEpatents

    Pardue, R.M.; Williams, R.R.

    1980-09-12

    A double-pass interferometer is provided which allows direct measurement of relative displacement between opposed surfaces. A conventional plane mirror interferometer may be modified by replacing the beam-measuring path cube-corner reflector with an additional quarterwave plate. The beam path is altered to extend to an opposed plane mirrored surface and the reflected beam is placed in interference with a retained reference beam split from dual-beam source and retroreflected by a reference cube-corner reflector mounted stationary with the interferometer housing. This permits direct measurement of opposed mirror surfaces by laser interferometry while doubling the resolution as with a conventional double-pass plane mirror laser interferometer system.

  17. Dual surface interferometer

    DOEpatents

    Pardue, Robert M.; Williams, Richard R.

    1982-01-01

    A double-pass interferometer is provided which allows direct measurement of relative displacement between opposed surfaces. A conventional plane mirror interferometer may be modified by replacing the beam-measuring path cube-corner reflector with an additional quarter-wave plate. The beam path is altered to extend to an opposed plane mirrored surface and the reflected beam is placed in interference with a retained reference beam split from dual-beam source and retroreflected by a reference cube-corner reflector mounted stationary with the interferometer housing. This permits direct measurement of opposed mirror surfaces by laser interferometry while doubling the resolution as with a conventional double-pass plane mirror laser interferometer system.

  18. The Palomar Testbed Interferometer

    NASA Technical Reports Server (NTRS)

    Colavita, M. M.; Wallace, J. K.; Hines, B. E.; Gursel, Y.; Malbet, F.; Palmer, D. L.; Pan, X. P.; Shao, M.; Yu, J. W.; Boden, A. F.

    1999-01-01

    The Palomar Testbed Interferometer (PTI) is a long-baseline infrared interferometer located at Palomar Observatory, California. It was built as a testbed for interferometric techniques applicable to the Keck Interferometer. First fringes were obtained in 1995 July. PTI implements a dual-star architecture, tracking two stars simultaneously for phase referencing and narrow-angle astrometry. The three fixed 40 cm apertures can be combined pairwise to provide baselines to 110 m. The interferometer actively tracks the white-light fringe using an array detector at 2.2 microns and active delay lines with a range of +/-38 m. Laser metrology of the delay lines allows for servo control, and laser metrology of the complete optical path enables narrow-angle astrometric measurements. The instrument is highly automated, using a multiprocessing computer system for instrument control and sequencing.

  19. Phase shifting diffraction interferometer

    DOEpatents

    Sommargren, G.E.

    1996-08-29

    An interferometer which has the capability of measuring optical elements and systems with an accuracy of {lambda}/1000 where {lambda} is the wavelength of visible light. Whereas current interferometers employ a reference surface, which inherently limits the accuracy of the measurement to about {lambda}/50, this interferometer uses an essentially perfect spherical reference wavefront generated by the fundamental process of diffraction. This interferometer is adjustable to give unity fringe visibility, which maximizes the signal-to-noise, and has the means to introduce a controlled prescribed relative phase shift between the reference wavefront and the wavefront from the optics under test, which permits analysis of the interference fringe pattern using standard phase extraction algorithms. 8 figs.

  20. Phase shifting diffraction interferometer

    DOEpatents

    Sommargren, Gary E.

    1996-01-01

    An interferometer which has the capability of measuring optical elements and systems with an accuracy of .lambda./1000 where .lambda. is the wavelength of visible light. Whereas current interferometers employ a reference surface, which inherently limits the accuracy of the measurement to about .lambda./50, this interferometer uses an essentially perfect spherical reference wavefront generated by the fundamental process of diffraction. This interferometer is adjustable to give unity fringe visibility, which maximizes the signal-to-noise, and has the means to introduce a controlled prescribed relative phase shift between the reference wavefront and the wavefront from the optics under test, which permits analysis of the interference fringe pattern using standard phase extraction algorithms.

  1. Michelson and His Interferometer

    ERIC Educational Resources Information Center

    Shankland, Robert S.

    1974-01-01

    Presents a brief historical account of Michelson's invention of his interferometer with some subsequent ingenious applications of its capabilities for precise measurement discussed in details, including the experiment on detrmination of the diameters for heavenly bodies. (CC)

  2. Condor equatorial electrojet campaign: Radar results

    SciTech Connect

    Kudeki, E.; Fejer, B.G.; Farley, D.T.; Hanuise, C.

    1987-12-01

    A review of the experimental and theoretical background to the Condor equatorial electrojet compaign is followed by the presentation and discussion of VHF radar interferometer and HF radar backscatter data taken concurrently with two rocket in situ experiments reported in companion papers (Pfaff et al., this issue (a, b). Both experiments were conducted in strongly driven periods with the on-line radar interferometer displaying signatures of what has been interpreted in earlier radar work (Kudeki et al., 1982) as kilometer scale gradient drift waves. Low-frequency density fluctuations detected by in situ rocket sensors confirm the earlier interpretation. VHF radar/rocket data comparisons also indicate the existence of a turbulent layer in the upper portion of the daytime electrojet at about 108 km altitude driven purely by the two-stream instability. Nonlinear mode coupling of linearly growing two-stream waves to linearly damped 3-m vertical modes could account for the radar echoes scattered from this layer, which showed no indication of large-scale gradient drift waves. Nonlinear mode coupling may therefore compete with the wave-induced anomalous diffusion mechanism proposed recently by Sudan (1983) for the saturation of directly excited two-stream waves. Nighttime radar data show a bifurcated layer with the two parts having comparable echo strength but oppositely directed zonal drift velocities. The lower layer shows narrow backscatter spectra; the upper layer is characterized by kilometer scale waves and vertically propagating type 1 waves.

  3. Single-Pass Flow-Through Test Elucidation of Weathering Behavior and Evaluation of Contaminant Release Models for Hanford Tank Residual Radioactive Waste

    SciTech Connect

    Cantrell, Kirk J.; Carroll, Kenneth C.; Buck, Edgar C.; Neiner, Doinita; Geiszler, Keith N.

    2013-01-01

    Contaminant release models are required to evaluate and predict long-term environmental impacts of even residual amounts of high-level radioactive waste after cleanup and closure of radioactively contaminated sites such as the DOE’s Hanford Site. More realistic and representative models have been developed for release of uranium, technetium, and chromium from Hanford Site tanks C-202, C-203, and C-103 residual wastes using data collected with a single-pass flow-through test (SPFT) method. These revised models indicate that contaminant release concentrations from these residual wastes will be considerably lower than previous estimates based on batch experiments. For uranium, a thermodynamic solubility model provides an effective description of uranium release, which can account for differences in pore fluid chemistry contacting the waste that could occur through time and as a result of different closure scenarios. Under certain circumstances in the SPFT experiments various calcium rich precipitates (calcium phosphates and calcite) form on the surfaces of the waste particles, inhibiting dissolution of the underlying uranium phases in the waste. This behavior was not observed in previous batch experiments. For both technetium and chromium, empirical release models were developed. In the case of technetium, release from all three wastes was modeled using an equilibrium Kd model. For chromium release, a constant concentration model was applied for all three wastes.

  4. Absorption characteristic of paeoniflorin-6'-O-benzene sulfonate (CP-25) in in situ single-pass intestinal perfusion in rats.

    PubMed

    Yang, Xiao-Dan; Wang, Chun; Zhou, Peng; Yu, Jun; Asenso, James; Ma, Yong; Wei, Wei

    2016-09-01

    1. Paeoniflorin-6'-O-benzene sulfonate (CP-25) was synthesized to improve the poor oral absorption of paeoniflorin (Pae). 2. This study was performed to investigate the absorptive behavior and mechanism of CP-25 in in situ single-pass intestinal perfusion in rats, using Pae as a control. 3. The results showed that intestinal absorption of CP-25 was neither segmental nor sex dependent. However, the main segment of intestine that absorbed Pae was the duodenum. Furthermore, passive transport was confirmed to be the main absorption pattern of CP-25. More importantly, the absorption of CP-25 was much higher than Pae in the small intestine. 4. Among the ABC transporter inhibitors, the absorption rate of Pae increased in the presence of P-gp inhibitors verapamil and GF120918, which indicated that Pae was a substrate of P-glycoprotein (P-gp), however, such was not observed in the presence of breast cancer resistance protein and multidrug resistance-associated protein 2. Finally, the ABC transporter inhibitors did not have any significant impact on CP-25 as demonstrated in the parallel studies. 5. CP-25 could improve the poor absorption of Pae, which may be attributed to both the lipid solubility enhancement and its resistance to P-gp-mediated efflux.

  5. A latent capacity of the C. elegans polycystins to disrupt sensory transduction is repressed by the single-pass ciliary membrane protein CWP-5

    PubMed Central

    Miller, Renee M.; Portman, Douglas S.

    2010-01-01

    SUMMARY Autosomal dominant polycystic kidney disease (ADPKD) results from loss-of-function mutations in PKD1 or PKD2. The products of these genes, the polycystins PC-1 and PC-2, form a transmembrane channel that is necessary for flow sensing by renal cilia. In C. elegans, the polycystin orthologs LOV-1 and PKD-2 function in sensory neurons that mediate male mating behavior. Here, we report that the novel single-pass membrane protein CWP-5 is necessary for polycystin signaling during the response step of mating behavior. As with the polycystins, CWP-5 localizes to neuronal cilia; this localization requires LOV-1. The response defect of cwp-5 mutants does not appear to result from disruption of ciliogenesis or polycystin localization. Instead, genetic and behavioral analyses indicate that CWP-5 represses a previously undescribed antagonistic effect of the polycystins on sensory function. Although cwp-5 does not have a primary-sequence ortholog in vertebrates, it has intriguing parallels with the autosomal recessive PKD gene FPC (also known as PKHD1). Together, this study identifies a new component of C. elegans polycystin signaling, demonstrates that the polycystins have a latent capacity to hinder sensory transduction, and suggests that aberrant functions of the polycystins could contribute to the pathogenesis of PKD. PMID:20223935

  6. Compactness of lateral shearing interferometers

    NASA Astrophysics Data System (ADS)

    Ferrec, Yann; Taboury, Jean; Sauer, Hervé; Chavel, Pierre

    2011-08-01

    Imaging lateral shearing interferometers are good candidates for airborne or spaceborne Fourier-transform spectral imaging. For such applications, compactness is one key parameter. In this article, we compare the size of four mirror-based interferometers, the Michelson interferometer with roof-top (or corner-cube) mirrors, and the cyclic interferometers with two, three, and four mirrors, focusing more particularly on the last two designs. We give the expression of the translation they induce between the two exiting rays. We then show that the cyclic interferometer with three mirrors can be made quite compact. Nevertheless, the Michelson interferometer is the most compact solution, especially for highly diverging beams.

  7. 5.7  W cw single-frequency laser at 671  nm by single-pass second harmonic generation of a 17.2  W injection-locked 1342  nm Nd : YVO4 ring laser using periodically poled MgO : LiNbO3.

    PubMed

    Koch, Peter; Ruebel, Felix; Bartschke, Juergen; L'huillier, Johannes A

    2015-11-20

    We demonstrate a continuous wave single-frequency laser at 671.1 nm based on a high-power 888 nm pumped Nd:YVO4 ring laser at 1342.2 nm. Unidirectional operation of the fundamental ring laser is achieved with the injection-locking technique. A Nd:YVO4 microchip laser serves as the injecting seed source, providing a tunable single-frequency power of up to 40 mW. The ring laser emits a single-frequency power of 17.2 W with a Gaussian beam profile and a beam propagation factor of M2<1.1. A 60-mm-long periodically poled MgO-doped LiNbO3 crystal is used to generate the second harmonic in a single-pass scheme. Up to 5.7 W at 671.1 nm with a Gaussian shaped beam profile and a beam propagation factor of M2<1.2 are obtained, which is approximately twice the power of previously reported lasers. This work opens possibilities in cold atoms experiments with lithium, allowing the use of larger ensembles in magneto-optical traps or higher diffraction orders in atomic beam interferometers.

  8. PDX multichannel interferometer

    SciTech Connect

    Bitzer, R.; Ernst, W.; Cutsogeorge, G.

    1980-10-01

    A 10 channel, 140 GHz homodyne interferometer is described for use on PDX. One feature of this interferometer is the separation of the signal source and electronics from the power splitters, delay line, and receiving systems. The latter is situated near the upper and lower vacuum ports between the toroidal field magnets. A second feature is the signal stabilization of the EIO source by means of an AFC system. The complete interferometer is described including block diagrams, circuit diagrams, test data, and magnetic field test conducted on the preamplifiers, microwave diodes, isolators, etc., to determine the extent of magnetic shielding required. The description of the tracking filters and digital phase display circuit is referenced to accompanying reports.

  9. Heterodyne Interferometer Angle Metrology

    NASA Technical Reports Server (NTRS)

    Hahn, Inseob; Weilert, Mark A.; Wang, Xu; Goullioud, Renaud

    2010-01-01

    A compact, high-resolution angle measurement instrument has been developed that is based on a heterodyne interferometer. The common-path heterodyne interferometer metrology is used to measure displacements of a reflective target surface. In the interferometer setup, an optical mask is used to sample the measurement laser beam reflecting back from a target surface. Angular rotations, around two orthogonal axes in a plane perpendicular to the measurement- beam propagation direction, are determined simultaneously from the relative displacement measurement of the target surface. The device is used in a tracking telescope system where pitch and yaw measurements of a flat mirror were simultaneously performed with a sensitivity of 0.1 nrad, per second, and a measuring range of 0.15 mrad at a working distance of an order of a meter. The nonlinearity of the device is also measured less than one percent over the measurement range.

  10. Nimbus 4 michelson interferometer.

    PubMed

    Hanel, R A; Schlachman, B; Rogers, D; Vanous, D

    1971-06-01

    The Michelson interferometer, IRIS-D, flown on Nimbus 4 in April 1970 is an improved version of the interferometer, IRIS-B, flown on Nimbus 3 a year earlier. Thermal emission spectra of the earth are being recorded between 400 cm(-1) and 1600 cm(-1) with a nominal spectral resolution of 2.8 cm(-1) and a noise equivalent radiance between approximately 0.5 and 1 erg sec(-1) cm(-2) ster(-1) cm. This paper describes the design and performance of the IRIS-D and concentrates on the design differences that exist between the interferometers flown on Nimbus 3 and 4. The performance is demonstrated by examples of spectra obtained while in earth orbit.

  11. Mariner 9 Michelson interferometer.

    NASA Technical Reports Server (NTRS)

    Hanel, R.; Schlachman, B.; Rodgers, D.; Breihan, E.; Bywaters, R.; Chapman, F.; Rhodes, M.; Vanous, D.

    1972-01-01

    The Michelson interferometer on Mariner 9 measures the thermal emission spectrum of Mars between 200 and 2000 per cm (between 5 and 50 microns) with a spectral resolution of 2.4 per cm in the apodized mode. A noise equivalent radiance of 0.5 x 10 to the minus 7th W/sq cm/ster/cm is deduced from data recorded in orbit around Mars. The Mariner interferometer deviates in design from the Nimbus 3 and 4 interferometers in several areas, notably, by a cesium iodide beam splitter and certain aspects of the digital information processing. Special attention has been given to the problem of external vibration. The instrument performance is demonstrated by calibration data and samples of Mars spectra.

  12. Keck interferometer autoaligner

    NASA Astrophysics Data System (ADS)

    van Belle, Gerard T.; Colavita, M. Mark; Ligon, Edgar R., III; Moore, James D.; Palmer, Dean L.; Reder, Leonard J.; Smythe, Robert F.

    2003-02-01

    A key thrust of NASA's Origins program is the development of astronomical interferometers. Pursuing this goal in a cost-effective and expedient manner from the ground has led NASA to develop the Keck Interferometer, which saw first fringes between the twin 10m Keck telescopes in March of 2001. In order to enhance the imaging potential of this facility, and to add astrometric capabilities for the detection of giant planets about nearby stars, four 1.8 m 'outrigger' telescopes may be added to the interferometer. Robust performance of the multi-aperture instrument will require precise alignment of the large number of optical elements found in the six optical beamtrains spread about the observatory site. The requirement for timely and reliable alignments dictated the development of an automatic alignment system for the Keck Interferometer. The autoaligner consists of swing-arm actuators that insert light-emitting diodes on the optical axis at the location of each optical element, which are viewed by a simple fixed-focus CCD camera at the end of the beamtrain. Sub-pixel centroiding is performed upon the slightly out-of-focus target spots using images provided by a frame grabber, providing steering information to the two-axis actuated optical elements. Resulting mirror-to-mirror alignments are good to within 2 arcseconds, and trimming the alignment of a full beamtrain is designed to take place between observations, within a telescope repointing time. The interactions of the autoaligner with the interferometer delay lines and coude trains are discussed in detail. The overall design of the interferometer's autoaligner system is presented, examining the design philosophy, system sequencing, optical element actuation, and subsystem co-alignment, within the context of satisfying performance requirements and cost constraints.

  13. Planetary Radar

    NASA Technical Reports Server (NTRS)

    Neish, Catherine D.; Carter, Lynn M.

    2015-01-01

    This chapter describes the principles of planetary radar, and the primary scientific discoveries that have been made using this technique. The chapter starts by describing the different types of radar systems and how they are used to acquire images and accurate topography of planetary surfaces and probe their subsurface structure. It then explains how these products can be used to understand the properties of the target being investigated. Several examples of discoveries made with planetary radar are then summarized, covering solar system objects from Mercury to Saturn. Finally, opportunities for future discoveries in planetary radar are outlined and discussed.

  14. The Glacier and Land Ice Surface Topography Interferometer (GLISTIN): A Novel Ka-band Digitally Beamformed Interferometer

    NASA Technical Reports Server (NTRS)

    Moller, Delwyn K.; Heavey, Brandon; Hodges, Richard; Rengarajan, Sembiam; Rignot, Eric; Rogez, Francois; Sadowy, Gregory; Simard, Marc; Zawadzki, Mark

    2006-01-01

    The estimation of the mass balance of ice sheets and glaciers on Earth is a problem of considerable scientific and societal importance. A key measurement to understanding, monitoring and forecasting these changes is ice-surface topography, both for ice-sheet and glacial regions. As such NASA identified 'ice topographic mapping instruments capable of providing precise elevation and detailed imagery data for measurements on glacial scales for detailed monitoring of ice sheet, and glacier changes' as a science priority for the most recent Instrument Incubator Program (IIP) opportunities. Funded under this opportunity is the technological development for a Ka-Band (35GHz) single-pass digitally beamformed interferometric synthetic aperture radar (InSAR). Unique to this concept is the ability to map a significant swath impervious of cloud cover with measurement accuracies comparable to laser altimeters but with variable resolution as appropriate to the differing scales-of-interest over ice-sheets and glaciers.

  15. Interferometer systems in machine industry

    NASA Astrophysics Data System (ADS)

    Rzepka, Janusz; Pienkowski, Janusz; Sambor, Slawomir; Budzyn, Grzegorz

    2003-10-01

    In the report the arrangements of laser interferometers for machine history are presented; the laser interferometer LSP30 for investigation of geometry of machine tools, the setup for inspection of ball screw and laser liner for CNC machine. Outstanding feature of the interferometers is the stabilization system of laser frequency using surface stabilized ferroelectric liquid cells (SSFLC).

  16. Mesoscopic Interferometers for Electron Waves

    SciTech Connect

    Rohrlich, D.

    2005-09-15

    Mesoscopic interferometers are electronic analogues of optical interferometers, with 'quantum point contacts' playing the role of optical beam splitters. Mesoscopic analogues of two-slit, Mach-Zehnder and Fabry-Perot interferometers have been built. A fundamental difference between electron and photon interferometry is that electron interferometry is nonlocal.

  17. The Stress-Relief Cracking Susceptibility of a New Ferritic Steel - Part I: Single-Pass Heat-Affected Zone Simulations

    SciTech Connect

    NAWROCKI,J.G.; DUPONT,J.N.; ROBINO,CHARLES V.; MARDER,A.R.

    1999-12-15

    The stress-relief cracking susceptibility of single-pass welds in a new ferritic steel, HCM2S, has been evaluated and compared to 2.25Cr-1Mo steel using Gleeble techniques. Simulated coarse-grained heat-affected zones (CGHAZ) were produced under a range of energy inputs and tested at various post-weld heat treatment (PWHT) temperatures. Both alloys were tested at a stress of 325 MPa. The 2.25 Cr-1Mo steel was also tested at 270 MPa to normalize for the difference in yield strength between the two materials. Light optical and scanning electron microscopy were used to characterize the CGHAZ microstructure. The ''as-welded'' CGHAZ of each alloy consisted of lath martensite or bainite and had approximately equal prior austenite grain sizes. The as-welded hardness of the 2.25Cr-1Mo steel CGHAZ was significantly higher than that of the HCM2S alloy. Over the range studied energy input had no effect on the as-welded microstructure or hardness of either alloy. The energy input also had no effect on the stress-relief cracking susceptibility of either material. Both alloys failed intergranularly along prior austenite grain boundaries under all test conditions. The 2.25Cr-1Mo steel samples experienced significant macroductility and some microductility when tested at 325 MPa. The ductility decreased significantly when tested at 270 MPa but was still higher that than of HCM2S at each test condition. The time to failure decreased with increasing PWHT Temperature for each material. There was no significant difference in the times to failure between the two materials. Varying energy input and stress had no effect on the time-to failure. The ductility, as measured by reduction in are% increased with increasing PWHT temperature for 2.25 Cr-1Mo steel tested at both stresses. However, PWHT temperature had no effect on the ductility of HCM2S. The hardness of the CGHAZ for 2.25Cr-1Mo steel decreased significantly after PWHT, but remained constant for HCM2S. The differences in stress

  18. Atom Wave Interferometer

    DTIC Science & Technology

    1991-04-05

    make improved measurements of the polarizability of sodium and the Aharonov - Casher effect . RECENT PUBLICATIONS Experimenal Study of Sub-Poissonian...constructing interferometers with varying degrees of beam collimation, and we plan to study the effects of source coherence (the collimator does not

  19. Dual beam optical interferometer

    NASA Technical Reports Server (NTRS)

    Gutierrez, Roman C. (Inventor)

    2003-01-01

    A dual beam interferometer device is disclosed that enables moving an optics module in a direction, which changes the path lengths of two beams of light. The two beams reflect off a surface of an object and generate different speckle patterns detected by an element, such as a camera. The camera detects a characteristic of the surface.

  20. Ultrasonic Interferometers Revisited

    ERIC Educational Resources Information Center

    Greenslade, Thomas B., Jr.

    2007-01-01

    I have been tinkering with ultrasonic transducers once more. In earlier notes I reported on optics-like experiments performed with ultrasonics, described a number of ultrasonic interferometers, and showed how ultrasonic transducers can be used for Fourier analysis. This time I became interested in trying the technique of using two detectors in…

  1. Rotatable shear plate interferometer

    DOEpatents

    Duffus, Richard C.

    1988-01-01

    A rotatable shear plate interferometer comprises a transparent shear plate mounted obliquely in a tubular supporting member at 45.degree. with respect to its horizontal center axis. This tubular supporting member is supported rotatably around its center axis and a collimated laser beam is made incident on the shear plate along this center axis such that defocus in different directions can be easily measured.

  2. Spaceborne radar

    NASA Technical Reports Server (NTRS)

    Moore, R. K.; Eckerman, J.; Meneghini, R.; Atlas, D.; Boerner, W. M.; Cherry, S.; Clark, J. F.; Doviak, R. J.; Goldhirsh, J.; Lhermitte, R. M.

    1981-01-01

    The spaceborne radar panel considered how radar could be used to measure precipitation from satellites. The emphasis was on how radar could be used with radiometry (at microwave, visible (VIS), and infrared (IR) wavelengths) to reduce the uncertainties of measuring precipitation with radiometry alone. In addition, the fundamental electromagnetic interactions involved in the measurements were discussed to determine the key work areas for research and development to produce effective instruments. Various approaches to implementing radar systems on satellites were considered for both shared and dedicated instruments. Finally, a research and development strategy was proposed for establishing the parametric relations and retrieval algorithms required for extracting precipitation information from the radar and associated radiometric data.

  3. Evaluation of the Long-Term Performance of Titanate Ceramics for Immobilization of Excess Weapons Plutonium: Results from Pressurized Unsaturated Flow and Single Pass Flow-Through Testing

    SciTech Connect

    BP McGrail; HT Schaef; JP Icenhower; PF Martin; RD Orr; VL Legore

    1999-09-13

    This report summarizes our findings from pressurized unsaturated flow (PUF) and single-pass flow-through (SPFT) experiments to date. Results from the PUF test of a Pu-bearing ceramic with enclosing surrogate high-level waste glass show that the glass reacts rapidly to alteration products. Glass reaction causes variations in the solution pH in contact with the ceramic materials. We also document variable concentrations of Pu in solution, primarily in colloidal form, which appear to be related to secular variations in solution composition. The apparent dissolution rate of the ceramic waste form, based on Ba concentrations in the effluent, is estimated at {le} 10{sup {minus}5} g/(m{sup 2} {center_dot} d). Pu-bearing colloids were recovered in the size range of 0.2 to 2 {micro}m, but it is not clear that such entities would be transported in a system that is not advective-flow dominated. Results from SPFT experiments give information on the corrosion resistance of two surrogate Pu-ceramics (Ce-pyrochlore and Ce-zirconolite) at 90 C over a pH range of 2 to 12. The two ceramics were doped with minor quantities ({approximately}0.1 mass%) of MoO{sub 3}, so that concentrations of Mo in the effluent solution could be used to monitor the reaction behavior of the materials. The data obtained thus far from experiments with durations up to 150 d do not conclusively prove that the solid-aqueous solution systems have reached steady-state conditions. Therefore, the dissolution mechanism cannot be determined. Apparent dissolution rates of the two ceramic materials based on Ce, Gd, and Mo concentrations in the effluent solutions from the SPFT are nearly identical and vary between 1.1 to 8.5 x 10{sup {minus}4} g/(m{sup 2} {center_dot} d). In addition, the data reveal a slightly amphoteric dissolution behavior, with a minimum apparent rate at pH = 7 to 8, over the pH range examined. Results from two related ceramic samples suggest that radiation damage can have a measurable effect on

  4. Double integrated laser interferometer

    NASA Astrophysics Data System (ADS)

    Motyka, Zbigniew

    2003-10-01

    The layout of integrated optical system compromising the basis of proposed solution of double laser interferometer composed of two integrated Michelson's interferometers is presented and shortly discussed. Such an integrated system is designed for work with two lasers of different wavelength. It may serve for mapping surfaces and deformations of objects under investigation with the use of simultaneous recording of two mutually orthogonal gratings, each one composed of equidistant, parallel interference fringes projected onto the surface of such an object. The picture resulting two-coloured is recorded with the digital camera and may be used for obtaining these maps and deformations directly or in the indirect way after suitable digital processing applied to each colour component separately.

  5. Interferometers without observable fringes

    NASA Astrophysics Data System (ADS)

    Garcia-Marquez, Jorge L.; Malacara-Hernandez, Daniel; Malacara-Doblado, Daniel

    1997-10-01

    There are some optical arrangements that closely resemble interferometric configurations but do not produce fringe patterns. An important characteristics of these devices is that they do not have two different outputs with complementary patterns, but only one. Some of these interferometers are described here, pointing out their common properties and differences. It is shown that if we open the second output, both complementary patterns will appear.

  6. Coaxial Mirau interferometer.

    PubMed

    Dobroiu, Adrian; Sakai, Hiroshi; Ootaki, Hitoshi; Sato, Manabu; Tanno, Naohiro

    2002-07-01

    We describe a new interferometric configuration for optical coherence tomography that is based on the Mirau interferometer. It uses the photodetector included in a superluminescent diode package, which makes possible a highly miniaturized device. Other advantages of the configuration include its totally coaxial structure, confocal microscope operation, availability of the full working distance of the imaging objective, and no central obscuration. Fundamental characteristics such as resolution and dynamic range are discussed, and the result of measurement on a rough metallic surface is presented.

  7. Multipulsed dynamic moire interferometer

    DOEpatents

    Deason, Vance A.

    1991-01-01

    An improved dynamic moire interferometer comprised of a lasing medium providing a plurality of beams of coherent light, a multiple q-switch producing multiple trains of 100,000 or more pulses per second, a combining means collimating multiple trains of pulses into substantially a single train and directing beams to specimen gratings affixed to a test material, and a controller, triggering and sequencing the emission of the pulses with the occurrence and recording of a dynamic loading event.

  8. RADAR WARNING SYSTEM,

    DTIC Science & Technology

    RADAR TRACKING, *AIRCRAFT DEFENSE SYSTEMS, RADAR EQUIPMENT, AIR TO AIR, SEARCH RADAR, GUIDED MISSILES, HIGH SPEED BOMBING, EARLY WARNING SYSTEMS, FIRE CONTROL SYSTEM COMPONENTS, AIRCRAFT, TIME, CHINA.

  9. Atom-Light Hybrid Interferometer

    NASA Astrophysics Data System (ADS)

    Chen, Bing; Qiu, Cheng; Chen, Shuying; Guo, Jinxian; Chen, L. Q.; Ou, Z. Y.; Zhang, Weiping

    2015-07-01

    A new type of hybrid atom-light interferometer is demonstrated with atomic Raman amplification processes replacing the beam splitting elements in a traditional interferometer. This nonconventional interferometer involves correlated optical and atomic waves in the two arms. The correlation between atoms and light developed with the Raman process makes this interferometer different from conventional interferometers with linear beam splitters. It is observed that the high-contrast interference fringes are sensitive to the optical phase via a path change as well as the atomic phase via a magnetic field change. This new atom-light correlated hybrid interferometer is a sensitive probe of the atomic internal state and should find wide applications in precision measurement and quantum control with atoms and photons.

  10. Atom-Light Hybrid Interferometer.

    PubMed

    Chen, Bing; Qiu, Cheng; Chen, Shuying; Guo, Jinxian; Chen, L Q; Ou, Z Y; Zhang, Weiping

    2015-07-24

    A new type of hybrid atom-light interferometer is demonstrated with atomic Raman amplification processes replacing the beam splitting elements in a traditional interferometer. This nonconventional interferometer involves correlated optical and atomic waves in the two arms. The correlation between atoms and light developed with the Raman process makes this interferometer different from conventional interferometers with linear beam splitters. It is observed that the high-contrast interference fringes are sensitive to the optical phase via a path change as well as the atomic phase via a magnetic field change. This new atom-light correlated hybrid interferometer is a sensitive probe of the atomic internal state and should find wide applications in precision measurement and quantum control with atoms and photons.

  11. SISAM interferometer for distance measurements.

    PubMed

    Verrier, I; Brun, G; Goure, J P

    1997-09-01

    We measure short distances with a spectromètre interférentiel à sélection par l'amplitude de la modulation (SISAM) (interferential spectrometer by selection of amplitude modulation) interferometer that correlates optical fields. We present the method and the resolution of the system. A test with a Michelson interferometer shows SISAM's ability to detect phase change in one arm of the Michelson interferometer.

  12. Polar mesosphere summer echoes observed with the EISCAT 933-MHz radar and the CUPRI 46.9-MHz radar, their similarity to 224-MHz radar echoes, and their relation to turbulence and electron density profiles

    NASA Astrophysics Data System (ADS)

    Roettger, J.; Rietveld, M. T.; La Hoz, C.; Hall, T.; Kelley, M. C.

    1990-08-01

    The relation of the coherent echoes from the mesosphere detected by an incoherent scatter UHF radar to the echoes registered simultaneously with a portable radar interferometer is analyzed. It is demonstrated that these 933-MHz echoes are of the same character as the VHF radar polar mesosphere summer echoes. It is also noted that a narrow electron density observed in the incoherent scatter UHF radar data occurs at the comparable altitude as the portable radar interferometer polar mesosphere summer echoes (PMSE). Potential origins of the scattering process of the PMSEs observed in VHF and UHF are discussed, with focus placed on enhanced electron density fluctuations as well as steep electron density gradients in the presence of cluster ions in the cold polar mesosphere.

  13. Orbiting Space Interferometer (OSI): A first generation space interferometer

    NASA Technical Reports Server (NTRS)

    Shao, Michael

    1992-01-01

    The technical requirements and performance of a first generation space interferometer is discussed. The performance of an interferometer, sensitivity, field of view, dynamic range, astrometric accuracy, etc, in space is set by what cannot be achieved for a ground-based instrument. For the Orbiting Space Interferometer (OSI), the nominal performance parameters are 20 mag sensitivity, field of view of approximately 500*500 pixels, a 1000:1 dynamic range in the image with one milliarcsec resolution, and an astrometric accuracy of 0.1 milliarcsec for wide angle astrometry and 10 microarcsec accuracy for narrow field astrometry (few degrees). OSI is a fully phased interferometer where all critical optical paths are controlled to 0.05 wavelengths. The instrument uses two guide interferometers locked on bright stars several degrees away to provide the spacecraft attitude information needed to keep the fringes from the faint science object stable on the detector.

  14. Holographic Twyman-Green Interferometer

    NASA Technical Reports Server (NTRS)

    Chen, C. W.; Wyant, J. C.; Breckinridge, J. B.

    1984-01-01

    Off-axis Fresnel zone plate used to obtain fringe visibility close to unity. Holographic Twyman-Green Interferometer (HTG) employs off-axis Fresnel zone plate (OFZP) as beam splitter and beam diverger in place of two separate elements that perform those functions in conventional TwymanGreen interferometer.

  15. Wavelength independent interferometer

    NASA Technical Reports Server (NTRS)

    Hochberg, Eric B. (Inventor); Page, Norman A. (Inventor)

    1991-01-01

    A polychromatic interferometer utilizing a plurality of parabolic reflective surfaces to properly preserve the fidelity of light wavefronts irrespective of their wavelengths as they pass through the instrument is disclosed. A preferred embodiment of the invention utilizes an optical train which comprises three off-axis parabolas arranged in conjunction with a beam-splitter and a reference mirror to form a Twyman-Green interferometer. An illumination subsystem is provided and comprises a pair of lasers at different preselected wavelengths in the visible spectrum. The output light of the two lasers is coaxially combined by means of a plurality of reflectors and a grating beam combiner to form a single light source at the focal point of the first parabolic reflection surface which acts as a beam collimator for the rest of the optical train. By using visible light having two distinct wavelengths, the present invention provides a long equivalent wavelength interferogram which operates at visible light wherein the effective wavelength is equal to the product of the wavelengths of the two laser sources divided by their difference in wavelength. As a result, the invention provides the advantages of what amounts to long wavelength interferometry but without incurring the disadvantage of the negligible reflection coefficient of the human eye to long wavelength frequencies which would otherwise defeat any attempt to form an interferogram at that low frequency using only one light source.

  16. Folding gravitational-wave interferometers

    NASA Astrophysics Data System (ADS)

    Sanders, J. R.; Ballmer, Stefan W.

    2017-01-01

    The sensitivity of kilometer-scale terrestrial gravitational wave interferometers is limited by mirror coating thermal noise. Alternative interferometer topologies can mitigate the impact of thermal noise on interferometer noise curves. In this work, we explore the impact of introducing a single folding mirror into the arm cavities of dual-recycled Fabry–Perot interferometers. While simple folding alone does not reduce the mirror coating thermal noise, it makes the folding mirror the critical mirror, opening up a variety of design and upgrade options. Improvements to the folding mirror thermal noise through crystalline coatings or cryogenic cooling can increase interferometer range by as much as a factor of two over the Advanced LIGO reference design.

  17. Observation and Theory of the Radar Aurora

    NASA Astrophysics Data System (ADS)

    Sahr, John David

    1990-01-01

    Plasma density irregularities occurring near the Aurora Borealis cause scattering of HF, VHF, and UHF radio waves. The scattering is so strong that a small radar, such a the Cornell University Portable Radar Interferometer (CUPRI), can easily detect this "radar aurora." Analysis of the resulting radar signal provides great detail about the spatial and temporal characteristics of these auroral E region irregularities. We present observations of the radar aurora from recent campaigns in northern Sweden. After reviewing the basic theory and observations of auroral electrojet irregularities, we introduce a simple nonlinear fluid theory of electrojet ion-acoustic waves, and reduce it to a form of the "three-wave interaction" equations. This theory provides a simple mechanism for excitation of linearly stable waves at large aspect and flow angles, as well as a prediction of the power spectra that a coherent scatter radar should observe. In addition, this theory may be able account for "type 3" waves without resorting to ion gyro modes, such as the electrostatic ion-cyclotron wave. During the course of our research we have generated a simple new radar transmitting mode and signal processing algorithm which very simply solves a frequency aliasing problem that often occurs in CUPRI auroral radar studies when a single-pulse spectral mode is used. Several new radar data analysis routines have been developed, including principally the "cross-beam image" and scatter plots of the second versus first moments of the power spectrum of the irregularities. Analysis of vertical interferometer data shows that "type 3" waves originate at ordinary electrojet altitudes, not in the upper E region, from which we conclude that the electrostatic ion-cyclotron mode does not generate "type 3" waves. The measured height of type 3 waves and other spectral analyses provide support for our pure ion -acoustic theory of type 3 waves. In closing, we offer suggestions for hardware improvements to the

  18. Observation and theory of the radar aurora

    NASA Astrophysics Data System (ADS)

    Sahr, John David

    Plasma density irregularities occurring near the Aurora Borealis cause scattering of HF, VHF, and UHF radio waves. The scattering is so strong that a small radar, such as the Cornell University Portable Radar Interferometer (CUPRI), can easily detect this radar aurora. Analysis of the resulting radar signal provides great detail about the spatial and temporal characteristics of these auroral E region irregularities. Observations are presented of the radar aurora from recent campaigns in northern Sweden. After reviewing the basic theory and observations of auroral electrojet irregularities, a simple nonlinear fluid theory of electrojet ion-acoustic waves is introduced, and reduced to a form of the three-wave interaction equations. This theory provides a simple mechanism for excitation of linearly stable waves at large aspect and flow angles, as well as a prediction of the power spectra that a coherent scatter radar should observe. In addition, this theory may be able to account for type 3 waves without resorting to ion gyro modes, such as the electrostatic ion-cyclotron wave. During the course of the research a simple new radar transmitting mode and signal processing algorithm was generated which very simply solves a frequency aliasing problem that often occurs in CUPRI auroral radar studies when a single-pulse spectral mode is used. Several new radar data analysis routines were developed, including the principally cross-beam image and scatter plots of the second versus first moments of the power spectrum of the irregularities. Analysis of vertical interferometer data shows that type 3 waves originate at ordinary electrojet altitudes, not in the upper E region, from which it is concluded that the electrostatic ion-cyclotron mode does not generate type 3 waves. The measured height of type 3 waves and other spectral analyses provide support for the pure ion-acoustic theory of type 3 waves. Suggestions are offered for hardware improvements to the CUPRI radar, new

  19. Planetary radar

    NASA Technical Reports Server (NTRS)

    Taylor, R. M.

    1980-01-01

    The radar astronomy activities supported by the Deep Space Network during June, July, and August 1980 are reported. The planetary bodies observed were Venus, Mercury, and the asteroid Toro. Data were obtained at both S and X band, and the observations were considered successful.

  20. Closed-form expressions to fit data obtained with a multipass Fabry-Perot interferometer.

    PubMed

    Boukari, H; Palik, E D; Gammon, R W

    1995-01-01

    We have studied the effect of a multipass Fabry-Perot interferometer (FP) on a scattering line. Here we describe a method that we applied to derive a closed-form expression for a line shape obtained with an ideal, multipass FP. The method reduces the convolution problem between the multipass function and the scattering line to the corresponding single-pass problem. We illustrate the method with a Lorentzian and a damped-harmonic-oscillator line passed through a single-, triple-, and quintuple-pass FP. Furthermore we have applied the method to a study of the effect of the collecting pinhole on a sharp line obtained by multipassing. We show how we used these functions to fit the complete spectra obtained with a single- and triple-pass FP.

  1. A 250 GHz microwave interferometer for divertor experiments on DIII-D

    SciTech Connect

    James, R.A.; Nilson, D.G.; Stever, R.D.; Hill, D.N.; Casper, T.A.

    1994-01-31

    A new 250 GHz, two-frequency microwave interferometer system has been developed to diagnose divertor plasmas on DIII-D. This diagnostic will measure the line-averaged density across both the inner and outer, lower divertor legs. With a cut-off density of over 7 {times} 10{sup 14} cm{sup {minus}3}, temporal measurements of ELMs, MARFs and plasma detachment are expected. The outer leg system will use a double pass method while the inner leg system will be single pass. Two special 3D carbon composite tiles are used, one to protect the microwave antennas mounted directly under the strike point and the other as the outer leg reflecting surface. Performance, design constraints, and the thermalmechanical design of the 3D carbon composite tiles are discussed.

  2. The Fizeau Interferometer Testbed

    NASA Technical Reports Server (NTRS)

    Zhang, Xiaolei; Carpenter, Kenneth G.; Lyon, Richard G,; Huet, Hubert; Marzouk, Joe; Solyar, Gregory

    2003-01-01

    The Fizeau Interferometer Testbed (FIT) is a collaborative effort between NASA's Goddard Space Flight Center, the Naval Research Laboratory, Sigma Space Corporation, and the University of Maryland. The testbed will be used to explore the principles of and the requirements for the full, as well as the pathfinder, Stellar Imager mission concept. It has a long term goal of demonstrating closed-loop control of a sparse array of numerous articulated mirrors to keep optical beams in phase and optimize interferometric synthesis imaging. In this paper we present the optical and data acquisition system design of the testbed, and discuss the wavefront sensing and control algorithms to be used. Currently we have completed the initial design and hardware procurement for the FIT. The assembly and testing of the Testbed will be underway at Goddard's Instrument Development Lab in the coming months.

  3. Guided magnonic Michelson interferometer

    NASA Astrophysics Data System (ADS)

    Ahmed, Muhammad H.; Jeske, Jan; Greentree, Andrew D.

    2017-01-01

    Magnonics is an emerging field with potential applications in classical and quantum information processing. Freely propagating magnons in two-dimensional media are subject to dispersion, which limits their effective range and utility as information carriers. We show the design of a confining magnonic waveguide created by two surface current carrying wires placed above a spin-sheet, which can be used as a primitive for reconfigurable magnonic circuitry. We theoretically demonstrate the ability of such guides to counter the transverse dispersion of the magnon in a spin-sheet, thus extending the range of the magnon. A design of a magnonic directional coupler and controllable Michelson interferometer is shown, demonstrating its utility for information processing tasks.

  4. Radio Seeing Monitor Interferometer

    NASA Astrophysics Data System (ADS)

    Hiriart, David; Valdez, Jorge; Zaca, Placido; Medina, José L.

    2002-10-01

    A two-element interferometer for monitoring atmospheric phase fluctuations (radio seeing) is presented; this uses the unmodulated beacon signal at 11.715 GHz from a geostationary satellite. The system measures phase differences on the signal received by two small antennas separated by 50 m. The system incorporates the best features from previous designs: a heterodyne phase-lock receiver and an IQ demodulator system. Phase fluctuations measured at this frequency may be extrapolated to millimetric and submillimetric wavelengths since the atmosphere is not dispersive at these frequencies. The instrument has been tested at the Observatory San Pedro Martir (Mexico) at 2800 m above sea level. The final destination of the instrument is Cerro la Negra (Mexico), where the Large Millimeter Telescope is under construction, at an altitude of 4600 m.

  5. Guided magnonic Michelson interferometer.

    PubMed

    Ahmed, Muhammad H; Jeske, Jan; Greentree, Andrew D

    2017-01-30

    Magnonics is an emerging field with potential applications in classical and quantum information processing. Freely propagating magnons in two-dimensional media are subject to dispersion, which limits their effective range and utility as information carriers. We show the design of a confining magnonic waveguide created by two surface current carrying wires placed above a spin-sheet, which can be used as a primitive for reconfigurable magnonic circuitry. We theoretically demonstrate the ability of such guides to counter the transverse dispersion of the magnon in a spin-sheet, thus extending the range of the magnon. A design of a magnonic directional coupler and controllable Michelson interferometer is shown, demonstrating its utility for information processing tasks.

  6. Guided magnonic Michelson interferometer

    PubMed Central

    Ahmed, Muhammad H.; Jeske, Jan; Greentree, Andrew D.

    2017-01-01

    Magnonics is an emerging field with potential applications in classical and quantum information processing. Freely propagating magnons in two-dimensional media are subject to dispersion, which limits their effective range and utility as information carriers. We show the design of a confining magnonic waveguide created by two surface current carrying wires placed above a spin-sheet, which can be used as a primitive for reconfigurable magnonic circuitry. We theoretically demonstrate the ability of such guides to counter the transverse dispersion of the magnon in a spin-sheet, thus extending the range of the magnon. A design of a magnonic directional coupler and controllable Michelson interferometer is shown, demonstrating its utility for information processing tasks. PMID:28134271

  7. THE KECK INTERFEROMETER NULLER

    SciTech Connect

    Serabyn, E.; Mennesson, B.; Colavita, M. M.; Koresko, C.; Kuchner, M. J.

    2012-03-20

    The Keck Interferometer Nuller (KIN), the first operational separated-aperture infrared nulling interferometer, was designed to null the mid-infrared emission from nearby stars so as to ease the measurement of faint circumstellar emission. This paper describes the basis of the KIN's four-beam, two-stage measurement approach and compares it to the simpler case of a two-beam nuller. In the four-beam KIN system, the starlight is first nulled in a pair of nullers operating on parallel 85 m Keck-Keck baselines, after which 'cross-combination' on 4 m baselines across the Keck apertures is used to modulate and detect residual coherent off-axis emission. Comparison to the constructive stellar fringe provides calibration. The response to an extended source is similar in the two cases, except that the four-beam response includes a term due to the visibility of the source on the cross-combiner baseline-a small effect for relatively compact sources. The characteristics of the dominant null depth errors are also compared for the two cases. In the two-beam nuller, instrumental imperfections and asymmetries lead to a series of quadratic, positive-definite null leakage terms. For the four-beam nuller, the leakage is instead a series of correlation cross-terms combining corresponding errors in each of the two nullers, which contribute offsets only to the extent that these errors are correlated on the timescale of the measurement. This four-beam architecture has allowed a significant ({approx}order of magnitude) improvement in mid-infrared long-baseline fringe-visibility accuracies.

  8. The Keck Interferometer Nuller

    NASA Technical Reports Server (NTRS)

    Serabyn, E.; Mennesson, B.; Colavita, M. M.; Koresko, C.; Kuchner, M. J.

    2012-01-01

    The Keck Interferometer Nuller (KIN), the first operational separated-aperture infrared nulling interferometer, was designed to null the mid-infrared emission from nearby stars so as to ease the measurement of faint circumstellar emission. This paper describes the basis of the KIN's four-beam, two-stage measurement approach and compares it 10 the simpler case of a two-beam nuller. In the four-beam KIN system, the starlight is first nulled in a pair of nullers operating on parallel 85 m Keck-Keck baselines, after which "cross-combination" on 4 m baselines across the Keck apertures is used to modulate and detect residual coherent off-axis emission. Comparison to the constructive itellar fringe provides calibration. The response to an extended source is similar in the two cases, except that the four-beam response includes a term due to the visibility of the source on the cross-combiner baseline-a small effect for relatively compact sources. The characteristics of the dominant null depth errors are also compared for the two cases. In the two-beam nuller, instrumental imperfections and asymmetries lead to a series of quadratic, positivedefinite null leakage terms. For the four-beam nuller, the leakage is instead a series of correlation cross-tenns combining corresponding errors in each of the two nullers, which contribute offsets only to the extent that these errors are correlated on the timescale of the measurement. This four-beam architecture has allowed a significant (approx. order of magnitude) improvement in mid-infrared long-baseline fringe-visibility accuracies.

  9. The Keck Interferometer Nuller

    NASA Astrophysics Data System (ADS)

    Serabyn, E.; Mennesson, B.; Colavita, M. M.; Koresko, C.; Kuchner, M. J.

    2012-03-01

    The Keck Interferometer Nuller (KIN), the first operational separated-aperture infrared nulling interferometer, was designed to null the mid-infrared emission from nearby stars so as to ease the measurement of faint circumstellar emission. This paper describes the basis of the KIN's four-beam, two-stage measurement approach and compares it to the simpler case of a two-beam nuller. In the four-beam KIN system, the starlight is first nulled in a pair of nullers operating on parallel 85 m Keck-Keck baselines, after which "cross-combination" on 4 m baselines across the Keck apertures is used to modulate and detect residual coherent off-axis emission. Comparison to the constructive stellar fringe provides calibration. The response to an extended source is similar in the two cases, except that the four-beam response includes a term due to the visibility of the source on the cross-combiner baseline—a small effect for relatively compact sources. The characteristics of the dominant null depth errors are also compared for the two cases. In the two-beam nuller, instrumental imperfections and asymmetries lead to a series of quadratic, positive-definite null leakage terms. For the four-beam nuller, the leakage is instead a series of correlation cross-terms combining corresponding errors in each of the two nullers, which contribute offsets only to the extent that these errors are correlated on the timescale of the measurement. This four-beam architecture has allowed a significant (~order of magnitude) improvement in mid-infrared long-baseline fringe-visibility accuracies.

  10. MIT's interferometer CST testbed

    NASA Technical Reports Server (NTRS)

    Hyde, Tupper; Kim, ED; Anderson, Eric; Blackwood, Gary; Lublin, Leonard

    1990-01-01

    The MIT Space Engineering Research Center (SERC) has developed a controlled structures technology (CST) testbed based on one design for a space-based optical interferometer. The role of the testbed is to provide a versatile platform for experimental investigation and discovery of CST approaches. In particular, it will serve as the focus for experimental verification of CSI methodologies and control strategies at SERC. The testbed program has an emphasis on experimental CST--incorporating a broad suite of actuators and sensors, active struts, system identification, passive damping, active mirror mounts, and precision component characterization. The SERC testbed represents a one-tenth scaled version of an optical interferometer concept based on an inherently rigid tetrahedral configuration with collecting apertures on one face. The testbed consists of six 3.5 meter long truss legs joined at four vertices and is suspended with attachment points at three vertices. Each aluminum leg has a 0.2 m by 0.2 m by 0.25 m triangular cross-section. The structure has a first flexible mode at 31 Hz and has over 50 global modes below 200 Hz. The stiff tetrahedral design differs from similar testbeds (such as the JPL Phase B) in that the structural topology is closed. The tetrahedral design minimizes structural deflections at the vertices (site of optical components for maximum baseline) resulting in reduced stroke requirements for isolation and pointing of optics. Typical total light path length stability goals are on the order of lambda/20, with a wavelength of light, lambda, of roughly 500 nanometers. It is expected that active structural control will be necessary to achieve this goal in the presence of disturbances.

  11. The single antenna interferometer

    SciTech Connect

    Fitch, J.P.

    1990-01-15

    Air and space borne platforms using synthetic aperture radars (SAR) have made interferometric measurements by using either two physical antennas mounted on one air-frame or two passes of one antenna over a scene. In this paper, a new interferometric technique using one pass of a single-antenna SAR system is proposed and demonstrated on data collected by the NASA-JPL AirSAR. Remotely sensed L-band microwave data are used to show the sensitivity of this technique to ocean surface features as well as a baseline for comparison with work by others using two-antenna systems. 7 refs., 3 figs.

  12. Comparison of high-fluence, single-pass diode laser to low-fluence, multiple-pass diode laser for laser hair reduction with 18 months of follow up.

    PubMed

    Braun, Martin

    2011-01-01

    Laser hair removal is the most popular laser procedure in the United States (U.S.), yet there has not been a prospective study demonstrating long-term efficacy of diode laser hair removal beyond six months. A prospective, single-center, bilaterally paired, blinded, randomized comparison split leg study was carried out with 22 patients comparing high-fluence, single-pass diode laser to low-fluence, multiple-pass diode laser. Hair counts were done six and 18 months following five treatment sessions and were found to be comparable t90-94 percent hair reduction. Hair counts at six months following the fifth treatment were comparable to hair counts at 18 months, indicating that sixth-month hair counts can be considered indicative of long-term results. The low-fluence, multiple-pass in-motion technique was associated with significantly less pain compared to the high-fluence, single-pass technique. Multiple passes of a diode laser at low fluences but with high average power results in permanent hair removal with less discomfort and fewer adverse effects, especially in darker skin.

  13. TRMM radar

    NASA Technical Reports Server (NTRS)

    Okamoto, Kenichi

    1993-01-01

    The results of a conceptual design study and the performance of key components of the Bread Board Model (BBM) of the Tropical Rainfall Measuring Mission (TRMM) radar are presented. The radar, which operates at 13.8 GHz and is designed to meet TRMM mission objectives, has a minimum measurable rain rate of 0.5 mm/h with a range resolution of 250 m, a horizontal resolution of about 4 km, and a swath width of 220 km. A 128-element active phased array system is adopted to achieve contiguous scanning within the swath. The basic characteristics of BBM were confirmed by experiments. The development of EM started with the cooperation of NASDA and CRL.

  14. Radar Sounder

    DTIC Science & Technology

    1988-09-01

    over the shorter time period (resulting in a multilook SAR ) with the result that spatial resolution, the usual r~ason for using SAR techniques, degrades...Field - - - ALT 21. Sea Surface Topography - - - SAR , ALT 22. Ocean Waves (sea, swell, surf) V. Good Some V. Good SAR , ALT * with additional lower freq...OLS - Operational Line-scan System radiometer (4-6 GHz?) ALT - Altimeter •* good at low microwave SAR - Synthetic Aperture frequencies Radar + over

  15. Overview of the Keck Interferometer

    NASA Technical Reports Server (NTRS)

    vanBelle, Gerard

    1999-01-01

    This is a presentation about the Keck Interferometer which is being constructed on top of Mauna Kea, Hawaii. This includes using the world's largest telescopes for optical and near-infrared astronomy, the twin 10 meter Keck telescopes. The two Keck telescopes, in conjunction with four proposed outrigger telescopes, will be used as an interferometer to conduct observations as part of NASA's Origins Program. These observations will address a variety of topics, including the origin and evolution of planetary systems. This presentation reviews the key features of the interferometer, and the specifications of the telescopes that will be used. It shows diagrams of the site, and the basement layout. It also reviews the science for which the interferometer will be used.

  16. Balloon exoplanet nulling interferometer (BENI)

    NASA Astrophysics Data System (ADS)

    Lyon, Richard G.; Clampin, Mark; Woodruff, Robert A.; Vasudevan, Gopal; Ford, Holland; Petro, Larry; Herman, Jay; Rinehart, Stephen; Carpenter, Kenneth; Marzouk, Joe

    2009-08-01

    We evaluate the feasibility of a balloon-borne nulling interferometer to detect and characterize an exosolar planet and the surrounding debris disk. The existing instrument consists of a three-telescope Fizeau imaging interferometer with thre fast steering mirrors and three delay lines operating at 800 Hz for closed-loop control of wavefront errors and fine pointing. A compact visible nulling interferometer would be coupled to the imaging interferometer and in principle, allows deep starlight suppression. Atmospheric simulations of the environment above 100,000 feet show that balloonborne payloads are a possible path towards the direct detection and characterization of a limited set of exoplanets and debris disks. Furthermore, rapid development of lower cost balloon payloads provide a path towards advancement of NASA technology readiness levels for future space-based exoplanet missions. Discussed are the BENI mission and instrument, the balloon environment and the feasibility of such a balloon-borne mission.

  17. Balloon Exoplanet Nulling Interferometer (BENI)

    NASA Technical Reports Server (NTRS)

    Lyon, Richard G.; Clampin, Mark; Woodruff, Robert A.; Vasudevan, Gopal; Ford, Holland; Petro, Larry; Herman, Jay; Rinehart, Stephen; Carpenter, Kenneth; Marzouk, Joe

    2009-01-01

    We evaluate the feasibility of using a balloon-borne nulling interferometer to detect and characterize exosolar planets and debris disks. The existing instrument consists of a 3-telescope Fizeau imaging interferometer with 3 fast steering mirrors and 3 delay lines operating at 800 Hz for closed-loop control of wavefront errors and fine pointing. A compact visible nulling interferometer is under development which when coupled to the imaging interferometer would in-principle allow deep suppression of starlight. We have conducted atmospheric simulations of the environment above 100,000 feet and believe balloons are a feasible path forward towards detection and characterization of a limited set of exoplanets and their debris disks. Herein we will discuss the BENI instrument, the balloon environment and the feasibility of such as mission.

  18. T 3-Interferometer for atoms

    NASA Astrophysics Data System (ADS)

    Zimmermann, M.; Efremov, M. A.; Roura, A.; Schleich, W. P.; DeSavage, S. A.; Davis, J. P.; Srinivasan, A.; Narducci, F. A.; Werner, S. A.; Rasel, E. M.

    2017-04-01

    The quantum mechanical propagator of a massive particle in a linear gravitational potential derived already in 1927 by Kennard [2, 3] contains a phase that scales with the third power of the time T during which the particle experiences the corresponding force. Since in conventional atom interferometers the internal atomic states are all exposed to the same acceleration a, this T^3-phase cancels out and the interferometer phase scales as T^2. In contrast, by applying an external magnetic field we prepare two different accelerations a_1 and a_2 for two internal states of the atom, which translate themselves into two different cubic phases and the resulting interferometer phase scales as T^3. We present the theoretical background for, and summarize our progress towards experimentally realizing such a novel atom interferometer.

  19. Compact portable diffraction moire interferometer

    DOEpatents

    Deason, Vance A.; Ward, Michael B.

    1989-01-01

    A compact and portable moire interferometer used to determine surface deformations of an object. The improved interferometer is comprised of a laser beam, optical and fiber optics devices coupling the beam to one or more evanescent wave splitters, and collimating lenses directing the split beam at one or more specimen gratings. Observation means including film and video cameras may be used to view and record the resultant fringe patterns.

  20. Compact portable diffraction moire interferometer

    DOEpatents

    Deason, V.A.; Ward, M.B.

    1988-05-23

    A compact and portable moire interferometer used to determine surface deformations of an object. The improved interferometer is comprised of a laser beam, optical and fiber optics devices coupling the beam to one or more evanescent wave splitters, and collimating lenses directing the split beam at one or more specimen gratings. Observations means including film and video cameras may be used to view and record the resultant fringe patterns. 7 figs.

  1. Surface profiling interferometer

    DOEpatents

    Takacs, Peter Z.; Qian, Shi-Nan

    1989-01-01

    The design of a long-trace surface profiler for the non-contact measurement of surface profile, slope error and curvature on cylindrical synchrotron radiation (SR) mirrors. The optical system is based upon the concept of a pencil-beam interferometer with an inherent large depth-of-field. The key feature of the optical system is the zero-path-difference beam splitter, which separates the laser beam into two colinear, variable-separation probe beams. A linear array detector is used to record the interference fringe in the image, and analysis of the fringe location as a function of scan position allows one to reconstruct the surface profile. The optical head is mounted on an air bearing slide with the capability to measure long aspheric optics, typical of those encountered in SR applications. A novel feature of the optical system is the use of a transverse "outrigger" beam which provides information on the relative alignment of the scan axis to the cylinder optic symmetry axis.

  2. Michelson Interferometer (MINT)

    NASA Technical Reports Server (NTRS)

    Lacis, Andrew; Carlson, Barbara

    1993-01-01

    MINT is a Michelson interferometer designed to measure the thermal emission from the earth at high spectral resolution (2/cm) over a broad spectral range (250-1700/cm, 6-40 mu m) with contiguous 3-pixel wide (12 mrad, 8 km field of view) along-track sampling. MINT is particularly well suited for monitoring cloud properties (cloud cover, effective temperature, optical thickness, ice/water phase, and effective particle size) both day and night, as well as tropospheric water vapor, ozone, and temperature. The key instrument characteristics that make MINT ideally suited for decadal monitoring purposes are: high wavelength to wavelength precision across the full IR spectrum with high spectral resolution; space-proven long-term durability and calibration stability; and small size, low cost, low risk instrument incorporating the latest detector and electronics technology. MINT also incorporates simplicity in design and operation by utilizing passively cooled DTGS detectors and nadir viewing geometry (with target motion compensation). MINT measurement objectives, instrument characteristics, and key advantages are summarized in this paper.

  3. Radar TopoMapper concept for planetary exploration

    NASA Astrophysics Data System (ADS)

    Madsen, Soren N.; Lou, Yun-Ling; Hensley, Scott; Harvey, Wayne L.; McKinnon, William B.

    2004-12-01

    Topographic information is key to interpreting the geology and geophysics of planetary bodies such as the icy Galilean satellites. Traditionally elevation information has been derived from stereo-photogrammetry, but the last couple of decades have offered new techniques, including radar interferometry, photoclinometry (shape from shading) and laser altimetry. Combining synthetic aperture radar (SAR) technology with interferometry (InSAR) enables high resolution imaging with elevation information at each image point. With two appropriately spaced antennas on a spacecraft, single-pass imaging radar interferometry can provide wide swath topographic data, independent of solar illumination, as was recently demonstrated on Earth by the Shuttle Topographic Radar Mission (SRTM; www.jpl.nasa.gov/srtm). We will present the science requirements, measurement principle, a straw-man"s design, and the predicted performance of a "compact SRTM" which could be flown on NASA missions such as the proposed Jupiter Icy Moons Orbiter (JIMO). In this paper we discuss challenges, including the calibration strategy and critical technology elements such as the high power RF-amplifier. We expect that the performance, both in terms of elevation accuracy and mapping rate would suffice to 1) determine topography on local and regional scales; 2) search for active geological change on the time scale of JIMO"s orbit around, e.g., Europa (30-60 days); and 3) determine the global tidal amplitude at Europa, Callisto, and Ganymede, which would constitute direct proof of the existence of oceans in all three icy moons.

  4. Continuous-wave quasi-phase-matched generation of 60thinspthinspmW at 465thinspthinspnm by single-pass frequency doubling of a laser diode in backswitch-poled lithium niobate

    SciTech Connect

    Batchko, R.G.; Fejer, M.M.; Byer, R.L.; Woll, D.; Wallenstein, R.; Shur, V.Y.; Erman, L.

    1999-09-01

    We report continuous-wave single-pass second-harmonic generation (SHG) in 4-{mu}m -period 0.5-mm-thick backswitch-poled lithium niobate. Pump sources at 920{endash}930thinspthinspnm include both Ti:sapphire and diode-oscillator{endash}amplifier lasers. SHG of a Ti:sapphire laser at 6.1{percent}/W efficiency, producing 61thinspthinspmW of power at 460thinspthinspnm, is demonstrated in 50-mm-long periodically poled lithium niobate samples with a nonlinear coefficient d{sub eff}{approx}9 pm/V , and 60thinspthinspmW at 465thinspthinspnm and 2.8{percent}/W efficiency is obtained by SHG of a laser-diode source. {copyright} {ital 1999} {ital Optical Society of America}

  5. Observation and theory of the radar aurora

    SciTech Connect

    Sahr, J.D.

    1990-01-01

    Plasma density irregularities occurring near the Aurora Borealis cause scattering of HF, VHF, and UHF radio waves. Analysis of the resulting radar signal provides great detail about the spatial and temporal characteristics of these auroral E region irregularities. Observations are presented of the radar aurora from recent campaigns in northern Sweden. After reviewing the basic theory and observations of auroral electrojet irregularities, a simple nonlinear fluid theory of electrojet ion-acoustic waves is introduced, and reduced to a form of the three-wave interaction equations. This theory provides a simple mechanism for excitation of linearly stable waves at large aspect and flow angles, as well as a prediction of the power spectra that a coherent scatter radar should observe. In addition, this theory may be able to account for type 3 waves without resorting to ion gyro modes, such as the electrostatic ion-cyclotron wave. During the course of the research a simple new radar transmitting mode and signal processing algorithm was generated which very simply solves a frequency aliasing problem that often occurs in CUPRI auroral radar studies. Several new radar data analysis routines were developed, including the principally cross-beam image and scatter plots of the second versus first moments of the power spectrum of the irregularities. Analysis of vertical interferometer data shows that type 3 waves originate at ordinary electrojet altitudes, not in the upper E region, from which it is concluded that the electrostatic ion-cyclotron mode does not generate type 3 waves. The measured height of type 3 waves and other spectral analyses provide support for the pure ion-acoustic theory of type 3 waves. Suggestions are offered for hardware improvements to the CUPRI radar, new experiments to test new and existing theories.

  6. Using dynamic interferometric synthetic aperature radar (InSAR) to image fast-moving surface waves

    DOEpatents

    Vincent, Paul

    2005-06-28

    A new differential technique and system for imaging dynamic (fast moving) surface waves using Dynamic Interferometric Synthetic Aperture Radar (InSAR) is introduced. This differential technique and system can sample the fast-moving surface displacement waves from a plurality of moving platform positions in either a repeat-pass single-antenna or a single-pass mode having a single-antenna dual-phase receiver or having dual physically separate antennas, and reconstruct a plurality of phase differentials from a plurality of platform positions to produce a series of desired interferometric images of the fast moving waves.

  7. Mesospheric wind measurements using a medium-frequency imaging Doppler interferometer

    NASA Technical Reports Server (NTRS)

    Adams, G. W.; scatterers.

    1986-01-01

    Wind results from a medium-frequency radar operated as an imaging Doppler interferometer are presented. Ten independent antennas, together with mesospheric wind motions, were used to Doppler-sort and then echo-locate individual scattering points. The three-dimensional location and radial velocity of each discrete scattering point was determined. Mean winds were then determined by a least squares fit to the radial velocities of the ensemble of scatterers.

  8. Liquid-helium-cooled Michelson interferometer

    NASA Technical Reports Server (NTRS)

    Augason, G. C.; Young, N.

    1972-01-01

    Interferometer serves as a rocket-flight spectrometer for examination of the far infrared emission spectra of astronomical objects. The double beam interferometer is readily adapted to make spectral scans and for use as a detector of discrete line emissions.

  9. Single Pass Electron Cooling Simulations for MEIC

    SciTech Connect

    Bell, G. I.; Pogorelov, I. V.; Schwartz, B. T.; Zhang, Yuhong; Zhang, He

    2013-12-01

    Cooling of medium energy protons is critical for the proposed Jefferson Lab Medium Energy Ion Collider (MEIC). We present simulations of electron cooling of protons up to 60 GeV. In the beam frame in which the proton and electrons are co-propagating, their motion is non-relativistic. We use a binary collision model which treats the cooling process as the sum of a large number of two-body collisions which are calculated exactly. This model can treat even very close collisions between an electron and ion with high accuracy. We also calculate dynamical friction using a delta-f PIC model. The code VSim (formerly Vorpal) is used to perform the simulations. We compare the friction rates with that obtained by a 3D integral over electron velocities which is used by BETACOOL.

  10. Radar and Lidar Radar DEM

    NASA Technical Reports Server (NTRS)

    Liskovich, Diana; Simard, Marc

    2011-01-01

    Using radar and lidar data, the aim is to improve 3D rendering of terrain, including digital elevation models (DEM) and estimates of vegetation height and biomass in a variety of forest types and terrains. The 3D mapping of vegetation structure and the analysis are useful to determine the role of forest in climate change (carbon cycle), in providing habitat and as a provider of socio-economic services. This in turn will lead to potential for development of more effective land-use management. The first part of the project was to characterize the Shuttle Radar Topography Mission DEM error with respect to ICESat/GLAS point estimates of elevation. We investigated potential trends with latitude, canopy height, signal to noise ratio (SNR), number of LiDAR waveform peaks, and maximum peak width. Scatter plots were produced for each variable and were fitted with 1st and 2nd degree polynomials. Higher order trends were visually inspected through filtering with a mean and median filter. We also assessed trends in the DEM error variance. Finally, a map showing how DEM error was geographically distributed globally was created.

  11. Interferometer for optical coherence tomography.

    PubMed

    Hauger, Christoph; Wörz, Marco; Hellmuth, Thomas

    2003-07-01

    We describe a new interferometer setup for optical coherence tomography (OCT). The interferometer is based on a fiber arrangement similar to Young's two-pinhole interference experiment with spatial coherent and temporal incoherent light. Depth gating is achieved detection of the interference signal on a linear CCD array. Therefore no reference optical delay scanning is needed. The interference signal, the modulation of the signal, the axial resolution, and the depth range are derived theoretically and compared with experiments. The dynamic range of the setup is compared with OCT sensors in the time domain. To our knowledge, the first images of porcine brain and heart tissue and human skin are presented.

  12. The Nimbus III Michelson Interferometer.

    PubMed

    Hanel, R A; Schlachman, B; Clark, F D; Prokesh, C H; Taylor, J B; Wilson, W M; Chaney, L

    1970-08-01

    The Michelson interferometer flown on Nimbus III in April 1969 has obtained infrared emission spectra of the earth and its atmosphere within 400 cm(-1) and 2000 cm(-1) (5 micro and 25 micro). Spectra of good quality have been recorded with a spectral resolution corresponding to 5 cm(-1). This paper discusses the design of the instrument including the optical layout, the phase locked loop operation of the Michelson motor, and the functioning of the reference interferometer. The methods of data reduction and in-flight calibration are demonstrated on sample spectra recorded while in orbit around the earth.

  13. The NIST Length Scale Interferometer

    PubMed Central

    Beers, John S.; Penzes, William B.

    1999-01-01

    The National Institute of Standards and Technology (NIST) interferometer for measuring graduated length scales has been in use since 1965. It was developed in response to the redefinition of the meter in 1960 from the prototype platinum-iridium bar to the wavelength of light. The history of the interferometer is recalled, and its design and operation described. A continuous program of modernization by making physical modifications, measurement procedure changes and computational revisions is described, and the effects of these changes are evaluated. Results of a long-term measurement assurance program, the primary control on the measurement process, are presented, and improvements in measurement uncertainty are documented.

  14. Multiplex Fabry-Perot interferometer

    NASA Technical Reports Server (NTRS)

    Hays, Paul B.; Snell, Hilary E.

    1991-01-01

    Attention is given to a Fabry-Perot interferometer (FPI) technique in which one of the etalon plates is moved over a large optical distance while the other remains fixed, thus exploiting the multiplex advantage of the instrument. This technique involves the application of Fourier-transform spectrometer to the multiple harmonics passing through the FPI etalon. It is shown that the multiplex FPI acts as several Michelson interferometers working at the same time, over the same spectral interval, and at different spectral resolutions. A high spectral resolution has been obtained over a large wavenumber interval, while the advantage of a reasonable scan length has been retained.

  15. Meteor Orbit Determinations with Multistatic Receivers Using the MU Radar

    NASA Astrophysics Data System (ADS)

    Fujiwara, Yasunori; Hamaguchi, Yoshiyuki; Nakamura, Takuji; Tsutsumi, Masaki; Abo, Makoto

    2008-06-01

    The MU radar of RISH (Research Institute for Sustainable Humanosphere, Kyoto University), which is a MST radar (46.5 MHz, 1 MW peak power), has been successfully applied to meteor studies by using its very high versatility. The system has recently renewed with 25 channel digital receivers which significantly improved the sensitivity and precision of interferometer used in meteor observation. The transmission is now synchronized to GPS signals, and two external receiving sites with a ranging capability has additionally been operated in order to determine the trajectories and speeds of meteoroids.

  16. Fiber-based swept-source terahertz radar.

    PubMed

    Huang, Yu-Wei; Tseng, Tzu-Fang; Kuo, Chung-Chiu; Hwang, Yuh-Jing; Sun, Chi-Kuang

    2010-05-01

    We demonstrate an all-terahertz swept-source imaging radar operated at room temperature by using terahertz fibers for radiation delivery and with a terahertz-fiber directional coupler acting as a Michelson interferometer. By taking advantage of the high water reflection contrast in the low terahertz regime and by electrically sweeping at a high speed a terahertz source combined with a fast rotating mirror, we obtained the living object's distance information with a high image frame rate. Our experiment showed that this fiber-based swept-source terahertz radar could be used in real time to locate concealed moving live objects with high stability.

  17. Interferometer for the measurement of plasma density

    DOEpatents

    Jacobson, Abram R.

    1980-01-01

    An interferometer which combines the advantages of a coupled cavity interferometer requiring alignment of only one light beam, and a quadrature interferometer which has the ability to track multi-fringe phase excursions unambiguously. The device utilizes a Bragg cell for generating a signal which is electronically analyzed to unambiguously determine phase modulation which is proportional to the path integral of the plasma density.

  18. Microwave interferometer controls cutting depth of plastics

    NASA Technical Reports Server (NTRS)

    Heisman, R. M.; Iceland, W. F.

    1969-01-01

    Microwave interferometer system controls the cutting of plastic materials to a prescribed depth. The interferometer is mounted on a carriage with a spindle and cutting tool. A cross slide, mounted on the carriage, allows the interferometer and cutter to move toward or away from the plastic workpiece.

  19. Holographic Twyman-Green interferometer.

    PubMed

    Chen, C W; Breckinridge, J B

    1982-07-15

    A dichromated gelatin off-axis Fresnel zone plate (OFZP) was designed, fabricated, and used in a new type of interferometer for optical metrology. This single hologram optical element combines the functions of a beam splitter, beam diverger, and aberrated null lens. Data presented show the successful application for an interferometric test of an f/6, 200-mm diam parabolic mirror.

  20. Holographic Twyman-Green interferometer

    NASA Technical Reports Server (NTRS)

    Chen, C. W.; Breckinridge, J. B.

    1982-01-01

    A dichromated gelatin off-axis Fresnel zone plate was designed, fabricated, and used in a new type of interferometer for optical metrology. This single hologram optical element combines the functions of a beam splitter, beam diverger, and aberrated null lens. Data presented show the successful application for an interferometric test of an f/6, 200-mm diam parabolic mirror.

  1. Standing waves in fiber-optic interferometers.

    PubMed

    de Haan, V; Santbergen, R; Tijssen, M; Zeman, M

    2011-10-10

    A study is presented giving the response of three types of fiber-optic interferometers by which a standing wave through an object is investigated. The three types are a Sagnac, Mach-Zehnder and Michelson-Morley interferometer. The response of the Mach-Zehnder interferometer is similar to the Sagnac interferometer. However, the Sagnac interferometer is much harder to study because of the fact that one input port and output port coincide. Further, the Mach-Zehnder interferometer has the advantage that the output ports are symmetric, reducing the systematic effects. Examples of standing wave light absorption in several simple objects are given. Attention is drawn to the influence of standing waves in fiber-optic interferometers with weak-absorbing layers incorporated. A method is described for how these can be theoretically analyzed and experimentally measured. Further experiments are needed for a thorough comparison between theory and experiment.

  2. Radar scattering from the summer polar mesosphere: Theory and observations

    NASA Astrophysics Data System (ADS)

    Cho, John Yungdo Nagamichi

    1993-12-01

    The anomalously large radar reflectivities observed in the summer polar mesosphere have eluded satisfactory explanation until now. We propose that the following chain of causality is responsible for the so-called polar mesosphere summer echoes (PMSE): The uniquely low temperatures in the summer mesopause produce ice aerosols. Because the aerosols exist in a plasma, they become electrically charged. The ambient electrons become coupled to the aerosols through electric fields and their effective diffusivity is retarded due to the large size of the aerosols. The reduction in diffusivity allows electron density inhomogeneities to be maintained at the radar Bragg scales. The radar waves are then scattered by the inhomogeneities. We support the above concept by developing a quantitative theory of ambipolar diffusion in the mesosphere. We then apply the results to isotropic turbulence and Fresnel radar scatter to show that the observed radar reflectivities can be explained by the theory. We show that the presence of realistic charged aerosols are sufficient to explain PMSE. We also show that dressed aerosol radar scatter, proposed by others as a generation mechanism for PMSE, can only apply to echoes detected by UHF radars. We present data taken with the Sondrestrom 1.29-GHz radar and attribute it to dressed aerosol scatter. In the summer of 1991, we used the Cornell University portable radar interferometer (CUPRI) to observe the mesosphere while rockets carrying in situ sensors were flown through two PMSE occurrences and a noctilucent cloud/PMSE event. We present a selection of first results from this campaign (NLC-91). The first simultaneous height comparison between noctilucent clouds and PMSE show that the radar scattering region was near or slightly above the visible cloud layer. We also infer from aspect sensitivity measurements and Doppler spectrograms that there were two distinct types of PMSE: enhanced turbulent scatter and partial (Fresnel) reflection from steep

  3. The proposed flatland radar

    NASA Technical Reports Server (NTRS)

    Green, J. L.; Gage, K. S.; Vanzandt, T. E.; Nastrom, G. D.

    1986-01-01

    A flexible very high frequency (VHF) stratosphere-troposphere (ST) radar configured for meteorological research is to be constructed near Urbana, Illinois. Measurement of small vertical velocities associated with synoptic-scale meteorology can be performed. A large Doppler microwave radar (CHILL) is located a few km from the site of the proposed ST radar. Since the microwave radar can measure the location and velocity of hydrometeors and the VHF ST radar can measure clear (or cloudy) air velocities, simultaneous observations by these two radars of stratiform or convective weather systems would provide valuable meteorological information.

  4. Nulling at the Keck Interferometer

    NASA Technical Reports Server (NTRS)

    Colavita, M. Mark; Serabyn, Gene; Wizinowich, Peter L.; Akeson, Rachel L.

    2006-01-01

    The nulling mode of the Keck Interferometer is being commissioned at the Mauna Kea summit. The nuller combines the two Keck telescope apertures in a split-pupil mode to both cancel the on-axis starlight and to coherently detect the residual signal. The nuller, working at 10 um, is tightly integrated with the other interferometer subsystems including the fringe and angle trackers, the delay lines and laser metrology, and the real-time control system. Since first 10 um light in August 2004, the system integration is proceeding with increasing functionality and performance, leading to demonstration of a 100:1 on-sky null in 2005. That level of performance has now been extended to observations with longer coherent integration times. An overview of the overall system is presented, with emphasis on the observing sequence, phasing system, and differences with respect to the V2 system, along with a presentation of some recent engineering data.

  5. Holography with a neutron interferometer

    NASA Astrophysics Data System (ADS)

    Sarenac, Dusan; Cory, David G.; Pushin, Dmitry A.; Heacock, Benjamin; Huber, Michael G.; Arif, M.; Clark, Charles W.; Shahi, Chandra B.; Cfref Collaboration

    2017-01-01

    We demonstrate the first neutron hologram of a macroscopic object. Using a Mach-Zehnder neutron interferometer in a configuration similar to the optical setup of Bazhenov et al., our reference beam passes through a fused silica prism that provides a linear phase gradient, and our object beam beam passes through an aluminum spiral phase plate with a topological charge of l = 2 , which was recently used in studies of neutron orbital angular momentum. Interference of reference and object beams in a two-dimensional imaging detector produces the hologram, which is a fork dislocation structure similar to those used to generate atomic and electronic vortex beams. Our neutron hologram is made in an interferometer in which at most one neutron is present at any given time.

  6. Customizable Digital Receivers for Radar

    NASA Technical Reports Server (NTRS)

    Moller, Delwyn; Heavey, Brandon; Sadowy, Gregory

    2008-01-01

    Compact, highly customizable digital receivers are being developed for the system described in 'Radar Interferometer for Topographic Mapping of Glaciers and Ice Sheets' (NPO-43962), NASA Tech Briefs, Vol. 31, No. 7 (August 2007), page 72. The receivers are required to operate in unison, sampling radar returns received by the antenna elements in a digital beam-forming (DBF) mode. The design of these receivers could also be adapted to commercial radar systems. At the time of reporting the information for this article, there were no commercially available digital receivers capable of satisfying all of the operational requirements and compact enough to be mounted directly on the antenna elements. A provided figure depicts the overall system of which the digital receivers are parts. Each digital receiver includes an analog-to-digital converter (ADC), a demultiplexer (DMUX), and a field-programmable gate array (FPGA). The ADC effects 10-bit band-pass sampling of input signals having frequencies up to 3.5 GHz. The input samples are demultiplexed at a user-selectable rate of 1:2 or 1:4, then buffered in part of the FPGA that functions as a first-in/first-out (FIFO) memory. Another part of the FPGA serves as a controller for the ADC, DMUX, and FIFO memory and as an interface between (1) the rest of the receiver and (2) a front-panel data port (FPDP) bus, which is an industry-standard parallel data bus that has a high data-rate capability and multichannel configuration suitable for DBF. Still other parts of the FPGA in each receiver perform signal-processing functions. The digital receivers can be configured to operate in a stand-alone mode, or in a multichannel mode as needed for DBF. The customizability of the receiver makes it applicable to a broad range of system architectures. The capability for operation of receivers in either a stand-alone or a DBF mode enables the use of the receivers in an unprecedentedly wide variety of radar systems.

  7. The Analysis of Moonborne Cross Track Synthetic Aperture Radar Interferometry for Global Environment Change Monitoring

    NASA Astrophysics Data System (ADS)

    Yixing, Ding; Huadong, Guo; Guang, Liu; Daowei, Zhang

    2014-03-01

    Faced to the earth observation requirement of large scale global environment change, a SAR (Synthetic Aperture Radar) antenna system is proposed to set on Moon's surface for interferometry in this paper. With several advantages superior to low earth obit SAR, such as high space resolution, large range swath and short revisit interval, the moonborne SAR could be a potential data resource of global changes monitoring and environment change research. Due to the high stability and ease of maintenance, the novel system is competent for offering a long and continuous time series of remote sensing imagery. The Moonborne SAR system performance is discussed at the beginning. Then, the peculiarity of interferometry is analyzed in both repeat pass and single pass cases. The chief distinguishing feature which is worth to research the potentiality of repeat pass interferometry is that the revisit interval is reduced to one day in most cases, and in worst case one month. Decorrelation deriving from geometry variety is discussed in detail. It turns out that the feasibility of moonborne SAR repeat pass interferometry depends on the declination of Moon. The severity of shift effects in radar echoes increased as Moon approaches to the equatorial plane. Moreover, referring to the single pass interferometry, two antennas are assumed to set on different latitude of Moon. There is enough space on Moon to form a long baseline, which is highly related to the interferogram precision.

  8. Stellar Interferometer Technology Experiment (SITE)

    NASA Technical Reports Server (NTRS)

    Crawley, Edward F.; Miller, David; Laskin, Robert; Shao, Michael

    1995-01-01

    The MIT Space Engineering Research Center and the Jet Propulsion Laboratory stand ready to advance science sensor technology for discrete-aperture astronomical instruments such as space-based optical interferometers. The objective of the Stellar Interferometer Technology Experiment (SITE) is to demonstrate system-level functionality of a space-based stellar interferometer through the use of enabling and enhancing Controlled-Structures Technologies (CST). SITE mounts to the Mission Peculiar Experiment Support System inside the Shuttle payload bay. Starlight, entering through two apertures, is steered to a combining plate where it is interferred. Interference requires 27 nanometer pathlength (phasing) and 0.29 archsecond wavefront-tilt (pointing) control. The resulting 15 milli-archsecond angular resolution exceeds that of current earth-orbiting telescopes while maintaining low cost by exploiting active optics and structural control technologies. With these technologies, unforeseen and time-varying disturbances can be rejected while relaxing reliance on ground alignment and calibration. SITE will reduce the risk and cost of advanced optical space systems by validating critical technologies in their operational environment. Moreover, these technologies are directly applicable to commercially driven applications such as precision matching, optical scanning, and vibration and noise control systems for the aerospace, medical, and automotive sectors. The SITE team consists of experienced university, government, and industry researchers, scientists, and engineers with extensive expertise in optical interferometry, nano-precision opto-mechanical control and spaceflight experimentation. The experience exists and the technology is mature. SITE will validate these technologies on a functioning interferometer science sensor in order to confirm definitely their readiness to be baselined for future science missions.

  9. Stellar Interferometer Technology Experiment (SITE)

    NASA Astrophysics Data System (ADS)

    Crawley, Edward F.; Miller, David; Laskin, Robert; Shao, Michael

    1995-02-01

    The MIT Space Engineering Research Center and the Jet Propulsion Laboratory stand ready to advance science sensor technology for discrete-aperture astronomical instruments such as space-based optical interferometers. The objective of the Stellar Interferometer Technology Experiment (SITE) is to demonstrate system-level functionality of a space-based stellar interferometer through the use of enabling and enhancing Controlled-Structures Technologies (CST). SITE mounts to the Mission Peculiar Experiment Support System inside the Shuttle payload bay. Starlight, entering through two apertures, is steered to a combining plate where it is interferred. Interference requires 27 nanometer pathlength (phasing) and 0.29 archsecond wavefront-tilt (pointing) control. The resulting 15 milli-archsecond angular resolution exceeds that of current earth-orbiting telescopes while maintaining low cost by exploiting active optics and structural control technologies. With these technologies, unforeseen and time-varying disturbances can be rejected while relaxing reliance on ground alignment and calibration. SITE will reduce the risk and cost of advanced optical space systems by validating critical technologies in their operational environment. Moreover, these technologies are directly applicable to commercially driven applications such as precision matching, optical scanning, and vibration and noise control systems for the aerospace, medical, and automotive sectors. The SITE team consists of experienced university, government, and industry researchers, scientists, and engineers with extensive expertise in optical interferometry, nano-precision opto-mechanical control and spaceflight experimentation. The experience exists and the technology is mature. SITE will validate these technologies on a functioning interferometer science sensor in order to confirm definitely their readiness to be baselined for future science missions.

  10. Weather Radar Technology Development

    DTIC Science & Technology

    1990-08-15

    uelocitV WMs ) data processing systems such as NEXRAD to have a reliable technique for removing ambiguities due to velocity aliasing. Performance of many...intended for automated implementation on radar systems such as the NEXt generation weather RADar ( NEXRAD ) system. Several research areas were addressed...with Doppler radar will soon be realized with the deployment of the NEXRAD radar systems. Some of these large scale storms can have devastating wind

  11. Polarized-interferometer feasibility study

    NASA Technical Reports Server (NTRS)

    Raab, F. H.

    1983-01-01

    The feasibility of using a polarized-interferometer system as a rendezvous and docking sensor for two cooperating spacecraft was studied. The polarized interferometer is a radio frequency system for long range, real time determination of relative position and attitude. Range is determined by round trip signal timing. Direction is determined by radio interferometry. Relative roll is determined from signal polarization. Each spacecraft is equipped with a transponder and an antenna array. The antenna arrays consist of four crossed dipoles that can transmit or receive either circularly or linearly polarized signals. The active spacecraft is equipped with a sophisticated transponder and makes all measurements. The transponder on the passive spacecraft is a relatively simple repeater. An initialization algorithm is developed to estimate position and attitude without any a priori information. A tracking algorithm based upon minimum variance linear estimators is also developed. Techniques to simplify the transponder on the passive spacecraft are investigated and a suitable configuration is determined. A multiple carrier CW signal format is selected. The dependence of range accuracy and ambiguity resolution error probability are derived and used to design a candidate system. The validity of the design and the feasibility of the polarized interferometer concept are verified by simulation.

  12. Unequal-Arms Michelson Interferometers

    NASA Technical Reports Server (NTRS)

    Tinto, Massimo; Armstrong, J. W.

    2000-01-01

    Michelson interferometers allow phase measurements many orders of magnitude below the phase stability of the laser light injected into their two almost equal-length arms. If, however, the two arms are unequal, the laser fluctuations can not be removed by simply recombining the two beams. This is because the laser jitters experience different time delays in the two arms, and therefore can not cancel at the photo detector. We present here a method for achieving exact laser noise cancellation, even in an unequal-arm interferometer. The method presented in this paper requires a separate readout of the relative phase in each arm, made by interfering the returning beam in each arm with a fraction of the outgoing beam. By linearly combining the two data sets with themselves, after they have been properly time shifted, we show that it is possible to construct a new data set that is free of laser fluctuations. An application of this technique to future planned space-based laser interferometer detector3 of gravitational radiation is discussed.

  13. Unequal-Arms Michelson Interferometers

    NASA Technical Reports Server (NTRS)

    Tinto, Massimo; Armstrong, J. W.

    1999-01-01

    Michelson interferometers allow phase measurements many orders of magnitude below the phase stability of the laser light injected into their two almost equal-length arms. If, however, the two arms are unequal, the laser fluctuations can not be removed by simply recombining the two beams. This is because the laser jitters experience different time delays in the two arms, and therefore can not cancel at the photo detector. We present here a method for achieving exact laser noise cancellation, even in an unequal-arm interferometer. The method presented in this paper requires a separate readout of the relative phase in each arm, made by interfering the returning beam in each arm with a fraction of the outgoing beam. By linearly combining the two data sets with themselves, after they have been properly time-shifted, we show that it is possible to construct a new data set that is free of laser fluctuations. An application of this technique to future planned space-based laser interferometer detectors of gravitational radiation is discussed.

  14. Radar: Human Safety Net

    ERIC Educational Resources Information Center

    Ritz, John M.

    2016-01-01

    Radar is a technology that can be used to detect distant objects not visible to the human eye. A predecessor of radar, called the telemobiloscope, was first used to detect ships in the fog in 1904 off the German coast. Many scientists have worked on the development and refinement of radar (Hertz with electromagnetic waves; Popov with determining…

  15. Lunar radar backscatter studies

    NASA Technical Reports Server (NTRS)

    Thompson, T. W.

    1979-01-01

    The lunar surface material in the Plato area is characterized using Earth based visual, infrared, and radar signatures. Radar scattering in the lunar regolith with an existing optical scattering computer program is modeled. Mapping with 1 to 2 km resolution of the Moon using a 70 cm Arecibo radar is presented.

  16. Equal-Path, Phase-Shifting, Sample-Point Interferometer

    NASA Technical Reports Server (NTRS)

    Manhart, Paul K.

    1991-01-01

    Proposed interferometer combination of sample-point interferometer and equal-path interferometer. Used to monitor optical figures of arrays of mirrors or of segmented mirrors. Incorporation of phase shifting with part of equal-path interferometer renders new interferometer insensitive to vibration and air turbulence. Instrument used over large distances, on ground, or on vibrating structures.

  17. Keck Interferometer Science: Present and Future

    NASA Technical Reports Server (NTRS)

    Akeson, Rachel L.

    2004-01-01

    The Keck Interferometer is a NASA funded project developed by the Jet Propulsion Laboratory, the William M. Keck Observatory and the Michelson Science Center at the California Institute of Technology. A technical description of the interferometer is given elsewhere in this volume. This paper will discuss the science topics and goals of the Keck Interferometer project, including a brief description of the Key Science projects, the science projects executed to date and the current availability of the interferometer for new projects. The Keck Interferometer Project consists of the Keck-Keck Interferometer, which combines the two Keck lo-meter telescopes on an 85-meter baseline, and the Outrigger Telescopes Project, a proposal to add four to six 1.8-meter telescopes that would work in conjunction with the two Kecks.

  18. Nonlocal polarization interferometer for entanglement detection

    DOE PAGES

    Williams, Brian P.; Humble, Travis S.; Grice, Warren P.

    2014-10-30

    We report a nonlocal interferometer capable of detecting entanglement and identifying Bell states statistically. This is possible due to the interferometer's unique correlation dependence on the antidiagonal elements of the density matrix, which have distinct bounds for separable states and unique values for the four Bell states. The interferometer consists of two spatially separated balanced Mach-Zehnder or Sagnac interferometers that share a polarization-entangled source. Correlations between these interferometers exhibit nonlocal interference, while single-photon interference is suppressed. This interferometer also allows for a unique version of the Clauser-Horne-Shimony-Holt Bell test where the local reality is the photon polarization. In conclusion, wemore » present the relevant theory and experimental results.« less

  19. Nonlocal polarization interferometer for entanglement detection

    SciTech Connect

    Williams, Brian P.; Humble, Travis S.; Grice, Warren P.

    2014-10-30

    We report a nonlocal interferometer capable of detecting entanglement and identifying Bell states statistically. This is possible due to the interferometer's unique correlation dependence on the antidiagonal elements of the density matrix, which have distinct bounds for separable states and unique values for the four Bell states. The interferometer consists of two spatially separated balanced Mach-Zehnder or Sagnac interferometers that share a polarization-entangled source. Correlations between these interferometers exhibit nonlocal interference, while single-photon interference is suppressed. This interferometer also allows for a unique version of the Clauser-Horne-Shimony-Holt Bell test where the local reality is the photon polarization. In conclusion, we present the relevant theory and experimental results.

  20. Infrared interferometer with a scanned aperture.

    PubMed

    Edwin, R P

    1975-08-01

    A Twyman-Green interferometer operating at a 3.39-microm wavelength has been built in which the collimator aperture was scanned by a laser beam. The scanning was produced by reflecting the laser beam from a mirror supported by four piezoelectric elements and oscillated about two orthogonal axes. The radiation transmitted by the interferometer was measured by a stationary detector of small area. The complete system offers a cheap and efficient alternative to conventional ir interferometers.

  1. Monolithically integrated interferometer for optical displacement measurement

    NASA Astrophysics Data System (ADS)

    Hofstetter, Daniel; Zappe, Hans P.

    1996-01-01

    We discuss the fabrication of a monolithically integrated optical displacement sensors using III-V semiconductor technology. The device is configured as a Michelson interferometer and consists of a distributed Bragg reflector laser, a photodetector and waveguides forming a directional coupler. Using this interferometer, displacements in the 100 nm range could be measured at distances of up to 45 cm. We present fabrication, device results and characterization of the completed interferometer, problems, limitations and future applications will also be discussed.

  2. Ordinary SQUID interferometers and superfluid helium matter wave interferometers: The role of quantum fluctuations

    SciTech Connect

    Golovashkin, A. I.; Zherikhina, L. N. Tskhovrebov, A. M.; Izmailov, G. N.; Ozolin, V. V.

    2010-08-15

    When comparing the operation of a superfluid helium matter wave quantum interferometer (He SQUID) with that of an ordinary direct-current quantum interferometer (dc SQUID), we estimate their resolution limitation that correspond to quantum fluctuations. An alternative mode of operation of the interferometer as a unified macroquantum system is considered.

  3. Radar stage uncertainty

    USGS Publications Warehouse

    Fulford, J.M.; Davies, W.J.

    2005-01-01

    The U.S. Geological Survey is investigating the performance of radars used for stage (or water-level) measurement. This paper presents a comparison of estimated uncertainties and data for radar water-level measurements with float, bubbler, and wire weight water-level measurements. The radar sensor was also temperature-tested in a laboratory. The uncertainty estimates indicate that radar measurements are more accurate than uncorrected pressure sensors at higher water stages, but are less accurate than pressure sensors at low stages. Field data at two sites indicate that radar sensors may have a small negative bias. Comparison of field radar measurements with wire weight measurements found that the radar tends to measure slightly lower values as stage increases. Copyright ASCE 2005.

  4. 2. VIEW SOUTHWEST, prime search radar tower, height finder radar ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. VIEW SOUTHWEST, prime search radar tower, height finder radar towards, height finder radar towers, and radar tower (unknown function) - Fort Custer Military Reservation, P-67 Radar Station, .25 mile north of Dickman Road, east of Clark Road, Battle Creek, Calhoun County, MI

  5. Holography with a neutron interferometer.

    PubMed

    Sarenac, Dusan; Huber, Michael G; Heacock, Benjamin; Arif, Muhammad; Clark, Charles W; Cory, David G; Shahi, Chandra B; Pushin, Dmitry A

    2016-10-03

    We use a Mach-Zehnder interferometer to perform neutron holography of a spiral phase plate. The object beam passes through a spiral phase plate, acquiring the phase twist characteristic of orbital angular momentum states. The reference beam passes through a fused silica prism, acquiring a linear phase gradient. The resulting hologram is a fork dislocation image, which could be used to reconstruct neutron beams with various orbital angular momenta. This work paves the way for novel applications of neutron holography, diffraction and imaging.

  6. Note: Periodic error measurement in heterodyne interferometers using a subpicometer accuracy Fabry-Perot interferometer.

    PubMed

    Zhu, Minhao; Wei, Haoyun; Wu, Xuejian; Li, Yan

    2014-08-01

    Periodic error is the major problem that limits the accuracy of heterodyne interferometry. A traceable system for periodic error measurement is developed based on a nonlinearity free Fabry-Perot (F-P) interferometer. The displacement accuracy of the F-P interferometer is 0.49 pm at 80 ms averaging time, with the measurement results referenced to an optical frequency comb. Experimental comparison between the F-P interferometer and a commercial heterodyne interferometer is carried out and it shows that the first harmonic periodic error dominates in the commercial heterodyne interferometer with an error amplitude of 4.64 nm.

  7. The calmodulin-like proteins AtCML4 and AtCML5 are single-pass membrane proteins targeted to the endomembrane system by an N-terminal signal anchor sequence

    PubMed Central

    Ruge, Henning; Flosdorff, Sandra; Ebersberger, Ingo; Chigri, Fatima; Vothknecht, Ute C.

    2016-01-01

    Calmodulins (CaMs) are important mediators of Ca2+ signals that are found ubiquitously in all eukaryotic organisms. Plants contain a unique family of calmodulin-like proteins (CMLs) that exhibit greater sequence variance compared to canonical CaMs. The Arabidopsis thaliana proteins AtCML4 and AtCML5 are members of CML subfamily VII and possess a CaM domain comprising the characteristic double pair of EF-hands, but they are distinguished from other members of this subfamily and from canonical CaMs by an N-terminal extension of their amino acid sequence. Transient expression of yellow fluorescent protein-tagged AtCML4 and AtCML5 under a 35S-promoter in Nicotiana benthamiana leaf cells revealed a spherical fluorescence pattern. This pattern was confirmed by transient expression in Arabidopsis protoplasts under the native promoter. Co-localization analyses with various endomembrane marker proteins suggest that AtCML4 and AtCML5 are localized to vesicular structures in the interphase between Golgi and the endosomal system. Further studies revealed AtCML5 to be a single-pass membrane protein that is targeted into the endomembrane system by an N-terminal signal anchor sequence. Self-assembly green fluorescent protein and protease protection assays support a topology with the CaM domain exposed to the cytosolic surface and not the lumen of the vesicles, indicating that AtCML5 could sense Ca2+ signals in the cytosol. Phylogenetic analysis suggests that AtCML4 and AtCML5 are closely related paralogues originating from a duplication event within the Brassicaceae family. CML4/5-like proteins seem to be universally present in eudicots but are absent in some monocots. Together these results show that CML4/5-like proteins represent a flowering plant-specific subfamily of CMLs with a potential function in vesicle transport within the plant endomembrane system. PMID:27029353

  8. Algorithms for Unequal-Arm Michelson Interferometers

    NASA Technical Reports Server (NTRS)

    Giampieri, Giacomo; Hellings, Ronald W.; Tinto, Massimo; Bender, Peter L.; Faller, James E.

    1994-01-01

    A method of data acquisition and data analysis is described in which the performance of Michelson-type interferometers with unequal arms can be made nearly the same as interferometers with equal arms. The method requires a separate readout of the relative phase in each arm, made by interfering the returning beam in each arm with a fraction of the outgoing beam.

  9. Dual-prism interferometer for collimation testing

    SciTech Connect

    Hii, King Ung; Kwek, Kuan Hiang

    2009-01-10

    An air-wedge lateral-shear interferometer using two prisms is presented. With a variable shear, the interferometer is suitable for testing collimation of a wide range of beam sizes down to a few millimeters in diameter. No antireflection coatings are necessary. Collimation for a light source with short coherent length is also demonstrated.

  10. Liquid-Crystal Point-Diffraction Interferometer

    NASA Technical Reports Server (NTRS)

    Mercer, Carolyn R.

    1996-01-01

    Liquid-crystal point-diffraction interferometer (LCPDI) invented to combine flexible control of liquid-crystal phase-shifts with robustness of point-diffraction interferometers. Produces interferograms indicative of shapes of wavefronts of laser beams having passed through or reflected from objects of interest. Interferograms combined in computers to produce phase maps describing wavefronts.

  11. In-fiber integrated Michelson interferometer

    NASA Astrophysics Data System (ADS)

    Yuan, Libo; Yang, Jun; Liu, Zhihai; Sun, Jiaxing

    2006-09-01

    A novel fiber-optic in-fiber integrated Michelson interferometer has been proposed and demonstrated. It consists of a segment of two-core fiber with a mirrored fiber end. The sensing characteristics based on the two-core fiber bending, corresponding to the shift of the phase of the two-core in-fiber integrated Michelson interferometer, are investigated.

  12. In-fiber integrated Michelson interferometer.

    PubMed

    Yuan, Libo; Yang, Jun; Liu, Zhihai; Sun, Jiaxing

    2006-09-15

    A novel fiber-optic in-fiber integrated Michelson interferometer has been proposed and demonstrated. It consists of a segment of two-core fiber with a mirrored fiber end. The sensing characteristics based on the two-core fiber bending, corresponding to the shift of the phase of the two-core in-fiber integrated Michelson interferometer, are investigated.

  13. CIST....CORRTEX interferometer simulation test

    SciTech Connect

    Heinle, R.A.

    1994-12-01

    Testing was performed in order to validate and cross calibrate an RF interferometer and the crush threshold of cable. Nitromethane was exploded (inside of PVC pipe). The explosion was used to crush the interferometer sensor cables which had been placed inside and outside the pipe. Results are described.

  14. Study Of Space-Based Optical Interferometer

    NASA Technical Reports Server (NTRS)

    Redding, David C.; Laskin, Robert A.; Breckenridge, William G.; Shao, Michael

    1992-01-01

    Report discusses calibration and operation of conceptual Focus Mission Interferometer (FMI), consisting of component instruments mounted at widely separated locations on large truss structure in orbit 1,400 km above Earth. Includes six telescopes in linear array. Outputs combined in pairlike fashion so FMI operates as three distinct two-telescope interferometers. Accurate enough for submilliarcsecond astrometry.

  15. TPF interferometer planet detection sensitivity

    NASA Astrophysics Data System (ADS)

    Elias, Nicholas M., II; Noecker, M. Charles

    2003-11-01

    Data-reduction algorithms for nulling interferometers can be divided into two categories, model-fitting and imaging. We deal mostly with single-Bracewell instruments because of their simplicity, even though they suffer from "nuisance sources" such as stellar leakage and exo-zodiacal light. To simplify data reduction, we work with the Fourier compo-nents of the time series. Exo-zodiacal light dominates at low frequencies. In principle, it should be possible to model the exo-zodiacal light contribution and separate it from planets using data from a single observation. In practice, however, the uncertainty in the exact form of the exo-zodiacal cloud limits our ability to model and remove its contribution. The only unambiguous way to detect planets with a single Bracewell is to observe a system multiple times through its orbit, and look for month-to-month variations in the Fourier components. To calculate the planet parameters, we discuss a cor-relation technique based on Fourier components instead of time series, in conjunction with a linearized least-squares so-lution. Because the fringe pattern on the sky is wavelength dependent, observations over multiple bandpasses signifi-cantly increases the confidence in planet detection. These algorithms may be used with other types of nulling interfer-ometers. We briefly discuss their application to dual Bracewell data.

  16. The DELTA Synchrotron Light Interferometer

    SciTech Connect

    Berges, U.

    2004-05-12

    Synchrotron radiation sources like DELTA, the Dortmund Electron Accelerator, a third generation synchrotron light source, need an optical monitoring system to measure the beam size at different points of the ring with high resolution and accuracy. These measurements also allow an investigation of the emittance of the storage ring, an important working parameter for the efficiency of working beamlines with experiments using the synchrotron radiation. The resolution limits of the different types of optical synchrotron light monitors at DELTA are investigated. The minimum measurable beamsize with the normal synchrotron light monitor using visible light at DELTA is about 80 {mu}m. Due to this a synchrotron light interferometer was built up and tested at DELTA. The interferometer uses the same beamline in the visible range. The minimum measurable beamsize is with about 8 {mu}m one order of magnitude smaller. This resolution is sufficient for the expected small vertical beamsizes at DELTA. The electron beamsize and emittance were measured with both systems at different electron beam energies of the storage ring. The theoretical values of the present optics are smaller than the measured emittance. So possible reasons for beam movements are investigated.

  17. Interferometer for Space Station Windows

    NASA Technical Reports Server (NTRS)

    Hall, Gregory

    2003-01-01

    Inspection of space station windows for micrometeorite damage would be a difficult task insitu using current inspection techniques. Commercially available optical profilometers and inspection systems are relatively large, about the size of a desktop computer tower, and require a stable platform to inspect the test object. Also, many devices currently available are designed for a laboratory or controlled environments requiring external computer control. This paper presents an approach using a highly developed optical interferometer to inspect the windows from inside the space station itself using a self- contained hand held device. The interferometer would be capable as a minimum of detecting damage as small as one ten thousands of an inch in diameter and depth while interrogating a relatively large area. The current developmental state of this device is still in the proof of concept stage. The background section of this paper will discuss the current state of the art of profilometers as well as the desired configuration of the self-contained, hand held device. Then, a discussion of the developments and findings that will allow the configuration change with suggested approaches appearing in the proof of concept section.

  18. 30. Perimeter acquisition radar building room #318, showing radar control. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    30. Perimeter acquisition radar building room #318, showing radar control. Console and line printers - Stanley R. Mickelsen Safeguard Complex, Perimeter Acquisition Radar Building, Limited Access Area, between Limited Access Patrol Road & Service Road A, Nekoma, Cavalier County, ND

  19. 3. VIEW NORTHWEST, height finder radar towers, and radar tower ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. VIEW NORTHWEST, height finder radar towers, and radar tower (unknown function) - Fort Custer Military Reservation, P-67 Radar Station, .25 mile north of Dickman Road, east of Clark Road, Battle Creek, Calhoun County, MI

  20. Interferometer Techniques for Gravitational-Wave Detection

    NASA Astrophysics Data System (ADS)

    Freise, Andreas; Strain, Kenneth

    2010-12-01

    Several km-scale gravitational-wave detectors have been constructed world wide. These instruments combine a number of advanced technologies to push the limits of precision length measurement. The core devices are laser interferometers of a new kind; developed from the classical Michelson topology these interferometers integrate additional optical elements, which significantly change the properties of the optical system. Much of the design and analysis of these laser interferometers can be performed using well-known classical optical techniques, however, the complex optical layouts provide a new challenge. In this review we give a textbook-style introduction to the optical science required for the understanding of modern gravitational wave detectors, as well as other high-precision laser interferometers. In addition, we provide a number of examples for a freely available interferometer simulation software and encourage the reader to use these examples to gain hands-on experience with the discussed optical methods.

  1. Orientational atom interferometers sensitive to gravitational waves

    SciTech Connect

    Lorek, Dennis; Laemmerzahl, Claus; Wicht, Andreas

    2010-02-15

    We present an atom interferometer that differs from common atom interferometers as it is not based on the spatial splitting of electronic wave functions, but on orienting atoms in space. As an example we present how an orientational atom interferometer based on highly charged hydrogen-like atoms is affected by gravitational waves. We show that a monochromatic gravitational wave will cause a frequency shift that scales with the binding energy of the system rather than with its physical dimension. For a gravitational wave amplitude of h=10{sup -23} the frequency shift is of the order of 110 {mu}Hz for an atom interferometer based on a 91-fold charged uranium ion. A frequency difference of this size can be resolved by current atom interferometers in 1 s.

  2. Optimal interferometer designs for optical coherence tomography.

    PubMed

    Rollins, A M; Izatt, J A

    1999-11-01

    We introduce a family of power-conserving fiber-optic interferometer designs for low-coherence reflectometry that use optical circulators, unbalanced couplers, and (or) balanced heterodyne detection. Simple design equations for optimization of the signal-to-noise ratio of the interferometers are expressed in terms of relevant signal and noise sources and measurable system parameters. We use the equations to evaluate the expected performance of the new configurations compared with that of the standard Michelson interferometer that is commonly used in optical coherence tomography (OCT) systems. The analysis indicates that improved sensitivity is expected for all the new interferometer designs, compared with the sensitivity of the standard OCT interferometer, under high-speed imaging conditions.

  3. Interferometer techniques for gravitational-wave detection

    NASA Astrophysics Data System (ADS)

    Bond, Charlotte; Brown, Daniel; Freise, Andreas; Strain, Kenneth A.

    2016-12-01

    Several km-scale gravitational-wave detectors have been constructed worldwide. These instruments combine a number of advanced technologies to push the limits of precision length measurement. The core devices are laser interferometers of a new kind; developed from the classical Michelson topology these interferometers integrate additional optical elements, which significantly change the properties of the optical system. Much of the design and analysis of these laser interferometers can be performed using well-known classical optical techniques; however, the complex optical layouts provide a new challenge. In this review, we give a textbook-style introduction to the optical science required for the understanding of modern gravitational wave detectors, as well as other high-precision laser interferometers. In addition, we provide a number of examples for a freely available interferometer simulation software and encourage the reader to use these examples to gain hands-on experience with the discussed optical methods.

  4. Interferometer techniques for gravitational-wave detection.

    PubMed

    Bond, Charlotte; Brown, Daniel; Freise, Andreas; Strain, Kenneth A

    2016-01-01

    Several km-scale gravitational-wave detectors have been constructed worldwide. These instruments combine a number of advanced technologies to push the limits of precision length measurement. The core devices are laser interferometers of a new kind; developed from the classical Michelson topology these interferometers integrate additional optical elements, which significantly change the properties of the optical system. Much of the design and analysis of these laser interferometers can be performed using well-known classical optical techniques; however, the complex optical layouts provide a new challenge. In this review, we give a textbook-style introduction to the optical science required for the understanding of modern gravitational wave detectors, as well as other high-precision laser interferometers. In addition, we provide a number of examples for a freely available interferometer simulation software and encourage the reader to use these examples to gain hands-on experience with the discussed optical methods.

  5. Planetary radar studies

    NASA Technical Reports Server (NTRS)

    Thompson, T. W.; Cutts, J. A.

    1981-01-01

    A catalog of lunar and radar anomalies was generated to provide a base for comparison with Venusian radar signatures. The relationships between lunar radar anomalies and regolith processes were investigated, and a consortium was formed to compare lunar and Venusian radar images of craters. Time was scheduled at the Arecibo Observatory to use the 430 MHz radar to obtain high resolution radar maps of six areas of the lunar suface. Data from 1978 observations of Mare Serenitas and Plato are being analyzed on a PDP 11/70 computer to construct the computer program library necessary for the eventual reduction of the May 1981 and subsequent data acquisitions. Papers accepted for publication are presented.

  6. Imaging system for low-density plasma by heterodyne interferometer with fan beam microwave

    NASA Astrophysics Data System (ADS)

    Ito, H.; Yugami, N.; Nishida, Y.; Sakai, W.

    2002-12-01

    A microwave imaging system based on a heterodyne interferometer has been developed to measure the spatial distribution of the plasma density without introducing any direct disturbance to the plasma by employing a diode array scattering technique. The imaging system with the use of a fan beam microwave for a radar system demonstrates the principle of the technique by placing finite-size dielectric phantoms instead of the plasma between the horn antenna and the diode antenna array. Experimental results show that very good image of the objects can be reconstructed and the system is equivalent to popularly known multichannel imaging system. As a result, it is possible to make simple, low-cost, and compact microwave interferometer for measuring the spatial distribution of the plasma density.

  7. Historical sketch: Radar geology

    NASA Technical Reports Server (NTRS)

    Macdonald, H.

    1980-01-01

    A chronological assessment is given of the broad spectra of technology associated with radar geology. Particular attention is given to the most recent developments made in the areas of microwave Earth resources applications and geologic remote sensing from aircraft and satellite. The significance of space derived radar in geologic investigations is discussed and the scientific basis for exploiting the sensitivity of radar signals to various aspects of geologic terrain is given.

  8. Interferometer for measuring dynamic corneal topography

    NASA Astrophysics Data System (ADS)

    Micali, Jason Daniel

    The cornea is the anterior most surface of the eye and plays a critical role in vision. A thin fluid layer, the tear film, coats the outer surface of the cornea and serves to protect, nourish, and lubricate the cornea. At the same time, the tear film is responsible for creating a smooth continuous surface where the majority of refraction takes place in the eye. A significant component of vision quality is determined by the shape of the cornea and stability of the tear film. It is desirable to possess an instrument that can measure the corneal shape and tear film surface with the same accuracy and resolution that is currently performed on common optical elements. A dual interferometer system for measuring the dynamic corneal topography is designed, built, and verified. The completed system is validated by testing on human subjects. The system consists of two co-aligned polarization splitting Twyman-Green interferometers designed to measure phase instantaneously. The primary interferometer measures the surface of the tear film while the secondary interferometer simultaneously tracks the absolute position of the cornea. Eye motion, ocular variation, and a dynamic tear film surface will result in a non-null configuration of the surface with respect to the interferometer system. A non-null test results in significant interferometer induced errors that add to the measured phase. New algorithms are developed to recover the absolute surface topography of the tear film and corneal surface from the simultaneous interferometer measurements. The results are high-resolution and high-accuracy surface topography measurements of the in vivo cornea that are captured at standard camera frame rates. This dissertation will cover the development and construction of an interferometer system for measuring the dynamic corneal topography of the human eye. The discussion starts with the completion of an interferometer for measuring the tear film. The tear film interferometer is part of an

  9. The TOPSAR interferometric radar topographic mapping instrument

    NASA Astrophysics Data System (ADS)

    Zebker, Howard A.

    1991-08-01

    We have augmented the NASA DC-8 Airborne Synthetic Aperture Radar (AIRSAR) instrument with a pair of C-band antennas displaced across the track to form an interferometer sensitive to topographic variations of the Earth's surface. The antennas were developed by Alenia Spazio under the sponsorship of the Italian Space Agency (ASI), and the AIRSAR instrument and modifications to it supporting TOPSAR were sponsored by NASA. A new data processor was developed at JPL for producing the topographic maps. As of May 1991, one engineering flight line over San Francisco, CA was reduced to a cartographically rectified topographic map. Analysis of the results indicates that statistical errors are in the range of 2 to 4 m, while systematic effects due to aircraft motion are in the range of 6 to 12 m. Future aircraft motion compensation algorithms should reduce the systematic variations to near zero, while the statistical errors could likely be reduced to 2 m or less with some processor improvements.

  10. The CryoSat Interferometer after 6 years in orbit: calibration and achievable performance

    NASA Astrophysics Data System (ADS)

    Scagliola, Michele; Fornari, Marco; De Bartolomei, Maurizio; Bouffard, Jerome; Parrinello, Tommaso

    2016-04-01

    The main payload of CryoSat is a Ku-band pulse width limited radar altimeter, called SIRAL (Synthetic interferometric radar altimeter). When commanded in SARIn (synthetic aperture radar interferometry) mode, through coherent along-track processing of the returns received from two antennas, the interferometric phase related to the first arrival of the echo is used to retrieve the angle of arrival of the scattering in the across-track direction. In fact, the across-track echo direction can be derived by exploiting the precise knowledge of the baseline vector (i.e. the vector between the two antennas centers of phase) and simple geometry. The end-to-end calibration strategy for the CryoSat interferometer consists on in-orbit calibration campaigns following the approach described in [1]. From the beginning of the CryoSat mission, about once a year the interferometer calibration campaigns have been periodically performed by rolling left and right the spacecraft of about ±0.4 deg. This abstract is aimed at presenting our analysis of the calibration parameters and of the achievable performance of the CryoSat interferometer over the 6 years of mission. Additionally, some further studies have been performed to assess the accuracy of the roll angle computed on ground as function of the aberration (the apparent displacement of a celestial object from its true position, caused by the relative motion of the observer and the object) correction applied to the attitude quaternions, provided by the Star Tracker mounted on-board. In fact, being the roll information crucial to obtain an accurate estimate of the angle of arrival, the data from interferometer calibration campaigns have been used to verify how the application of the aberration correction affects the roll information and, in turns, the measured angle of arrival. [1] Galin, N.; Wingham, D.J.; Cullen, R.; Fornari, M.; Smith, W.H.F.; Abdalla, S., "Calibration of the CryoSat-2 Interferometer and Measurement of Across

  11. Beam shuttering interferometer and method

    DOEpatents

    Deason, Vance A.; Lassahn, Gordon D.

    1993-01-01

    A method and apparatus resulting in the simplification of phase shifting interferometry by eliminating the requirement to know the phase shift between interferograms or to keep the phase shift between interferograms constant. The present invention provides a simple, inexpensive means to shutter each independent beam of the interferometer in order to facilitate the data acquisition requirements for optical interferometry and phase shifting interferometry. By eliminating the requirement to know the phase shift between interferograms or to keep the phase shift constant, a simple, economical means and apparatus for performing the technique of phase shifting interferometry is provide which, by thermally expanding a fiber optical cable changes the optical path distance of one incident beam relative to another.

  12. Angle interferometer cross axis errors

    SciTech Connect

    Bryan, J.B.; Carter, D.L.; Thompson, S.L.

    1994-01-01

    Angle interferometers are commonly used to measure surface plate flatness. An error can exist when the centerline of the double comer cube mirror assembly is not square to the surface plate and the guide bar for the mirror sled is curved. Typical errors can be one to two microns per meter. A similar error can exist in the calibration of rotary tables when the centerline of the double comer cube mirror assembly is not square to the axes of rotation of the angle calibrator and the calibrator axis is not parallel to the rotary table axis. Commercial double comer cube assemblies typically have non-parallelism errors of ten milli-radians between their centerlines and their sides and similar values for non-squareness between their centerlines and end surfaces. The authors have developed a simple method for measuring these errors and correcting them by remachining the reference surfaces.

  13. X-ray shearing interferometer

    DOEpatents

    Koch, Jeffrey A.

    2003-07-08

    An x-ray interferometer for analyzing high density plasmas and optically opaque materials includes a point-like x-ray source for providing a broadband x-ray source. The x-rays are directed through a target material and then are reflected by a high-quality ellipsoidally-bent imaging crystal to a diffraction grating disposed at 1.times. magnification. A spherically-bent imaging crystal is employed when the x-rays that are incident on the crystal surface are normal to that surface. The diffraction grating produces multiple beams which interfere with one another to produce an interference pattern which contains information about the target. A detector is disposed at the position of the image of the target produced by the interfering beams.

  14. Multiple spacecraft Michelson stellar interferometer

    NASA Technical Reports Server (NTRS)

    Stachnik, R. V.; Arnold, D.; Melroy, P.; Mccormack, E. F.; Gezari, D. Y.

    1984-01-01

    Results of an orbital analysis and performance assessment of SAMSI (Spacecraft Array for Michelson Spatial Interferometry) are presented. The device considered includes two one-meter telescopes in orbits which are identical except for slightly different inclinations; the telescopes achieve separations as large as 10 km and relay starlight to a central station which has a one-meter optical delay line in one interferometer arm. It is shown that a 1000-km altitude, zero mean inclination orbit affords natural scanning of the 10-km baseline with departures from optical pathlength equality which are well within the corrective capacity of the optical delay line. Electric propulsion is completely adequate to provide the required spacecraft motions, principally those needed for repointing. Resolution of 0.00001 arcsec and magnitude limits of 15 to 20 are achievable.

  15. Angle interferometer cross axis errors

    NASA Astrophysics Data System (ADS)

    Bryan, J. B.; Carter, D. L.; Thompson, S. L.

    1994-01-01

    Angle interferometers are commonly used to measure surface plate flatness. An error can exist when the centerline of the double comer cube mirror assembly is not square to the surface plate and the guide bar for the mirror sled is curved. Typical errors can be one to two microns per meter. A similar error can exist in the calibration of rotary tables when the centerline of the double comer cube mirror assembly is not square to the axes of rotation of the angle calibrator and the calibrator axis is not parallel to the rotary table axis. Commercial double comer cube assemblies typically have non-parallelism errors of ten milli-radians between their centerlines and their sides and similar values for non-squareness between their centerlines and end surfaces. The authors have developed a simple method for measuring these errors and correcting them.

  16. Hubble Extra Solar Planet Interferometer

    NASA Technical Reports Server (NTRS)

    Shao, M.

    1991-01-01

    This paper describes a proposed third-generation Hubble instrument for extra-solar planet detection, the Hubble Extra-Solar Planet Interferometer (HESPI). This instrument would be able to achieve starlight cancellation at the 10 exp 6 to 10 exp 8 level, given a stellar wavefront with phase errors comparable to the present Hubble telescope wavefront. At 10 exp 6 starlight cancellation, HESPI would be able to detect a Jupiter-like planet next to a star at a distance of about 10 parsec, for which there are about 400 candidate stars. This paper describes a novel approach for starlight suppression, using a combination of active control and single-mode spatial filters, to achieve starlight suppression far below the classical limit set by scattering due to microsurface imperfections. In preliminary lab experiments, suppression by a factor of 40 below the classical scatter limit due to optical wavefront errors has been demonstrated.

  17. Beam shuttering interferometer and method

    DOEpatents

    Deason, V.A.; Lassahn, G.D.

    1993-07-27

    A method and apparatus resulting in the simplification of phase shifting interferometry by eliminating the requirement to know the phase shift between interferograms or to keep the phase shift between interferograms constant. The present invention provides a simple, inexpensive means to shutter each independent beam of the interferometer in order to facilitate the data acquisition requirements for optical interferometry and phase shifting interferometry. By eliminating the requirement to know the phase shift between interferograms or to keep the phase shift constant, a simple, economical means and apparatus for performing the technique of phase shifting interferometry is provide which, by thermally expanding a fiber optical cable changes the optical path distance of one incident beam relative to another.

  18. Development of newly designed VHF interferometer system for observing earthquake-related atmospheric anomalies

    PubMed Central

    Yamamoto, Isao; Fujiwara, Hironobu; Kamogawa, Masashi; Iyono, Atsushi; Kroumov, Valeri; Azakami, Takashi

    2009-01-01

    Temporal correlation between atmospheric anomalies and earthquakes has recently been verified statistically through measuring VHF FM radio waves transmitted beyond the line-of-sight. In order to locate the sources of such atmospheric anomalies, we developed a VHF interferometer system (bistatic-radar type) capable of finding the arrival direction of FM radio waves scattered possibly by earthquake-related atmospheric anomalies. In general, frequency modulation of FM radio waves produces ambiguity of arrival direction. However, our system, employing high-sampling rates of the order of kHz, can precisely measure the arrival direction of FM radio waves by stacking received signals. PMID:20009381

  19. Development of newly designed VHF interferometer system for observing earthquake-related atmospheric anomalies.

    PubMed

    Yamamoto, Isao; Fujiwara, Hironobu; Kamogawa, Masashi; Iyono, Atsushi; Kroumov, Valeri; Azakami, Takashi

    2009-01-01

    Temporal correlation between atmospheric anomalies and earthquakes has recently been verified statistically through measuring VHF FM radio waves transmitted beyond the line-of-sight. In order to locate the sources of such atmospheric anomalies, we developed a VHF interferometer system (bistatic-radar type) capable of finding the arrival direction of FM radio waves scattered possibly by earthquake-related atmospheric anomalies. In general, frequency modulation of FM radio waves produces ambiguity of arrival direction. However, our system, employing high-sampling rates of the order of kHz, can precisely measure the arrival direction of FM radio waves by stacking received signals.

  20. GeoSAR: A Radar Terrain Mapping System for the New Millennium

    NASA Technical Reports Server (NTRS)

    Thompson, Thomas; vanZyl, Jakob; Hensley, Scott; Reis, James; Munjy, Riadh; Burton, John; Yoha, Robert

    2000-01-01

    GeoSAR Geographic Synthetic Aperture Radar) is a new 3 year effort to build a unique, dual-frequency, airborne Interferometric SAR for mapping of terrain. This is being pursued via a Consortium of the Jet Propulsion Laboratory (JPL), Calgis, Inc., and the California Department of Conservation. The airborne portion of this system will operate on a Calgis Gulfstream-II aircraft outfitted with P- and X-band Interferometric SARs. The ground portions of this system will be a suite of Flight Planning Software, an IFSAR Processor and a Radar-GIS Workstation. The airborne P-band and X-band radars will be constructed by JPL with the goal of obtaining foliage penetration at the longer P-band wavelengths. The P-band and X-band radar will operate at frequencies of 350 Mhz and 9.71 Ghz with bandwidths of either 80 or 160 Mhz. The airborne radars will be complemented with airborne laser system for measuring antenna positions. Aircraft flight lines and radar operating instructions will be computed with the Flight Planning Software The ground processing will be a two-step step process. First, the raw radar data will be processed into radar images and interferometer derived Digital Elevation Models (DEMs). Second, these radar images and DEMs will be processed with a Radar GIS Workstation which performs processes such as Projection Transformations, Registration, Geometric Adjustment, Mosaicking, Merging and Database Management. JPL will construct the IFSAR Processor and Calgis, Inc. will construct the Radar GIS Workstation. The GeoSAR Project was underway in November 1996 with a goal of having the radars and laser systems fully integrated onto the Calgis Gulfstream-II aircraft in early 1999. Then, Engineering Checkout and Calibration-Characterization Flights will be conducted through November 1999. The system will be completed at the end of 1999 and ready for routine operations in the year 2000.

  1. Polarization fidelity in an optical interferometer

    NASA Astrophysics Data System (ADS)

    Buscher, David F.; Baron, Fabien; Haniff, Christopher A.

    2008-07-01

    The optical trains of interferometers invariably contain oblique reflections that alter the polarization state of the light from the source. Even for arrays with symmetric optical paths, large systematic visibility errors can be introduced when observing sources with intrinsic polarization. We have identified the key metric for polarization fidelity in an optical interferometer - the diattenuation of the optical train - and we evaluate the visibility penalties incurred by an interferometer that is not optimized for polarimetric purity for a number of different types of polarized source.

  2. Dynamic models of Fabry-Perot interferometers.

    PubMed

    Redding, David; Regehr, Martin; Sievers, Lisa

    2002-05-20

    Long-baseline, high-finesse Fabry-Perot interferometers can be used to make distance measurements that are precise enough to detect gravity waves. This level of sensitivity is achieved in part when the interferometer mirrors are isolated dynamically, with pendulum mounts and high-bandwidth cavity length control servos to reduce the effects of seismic noise. We present dynamical models of the cavity fields and signals of Fabry-Perot interferometers for use in the design and evaluation of length control systems for gravity-wave detectors. Models are described and compared with experimental data.

  3. The Millimeter-Wave Bolometric Interferometer

    NASA Technical Reports Server (NTRS)

    Ali, S.; Ade, P. A. R.; Bock, J. J.; Novak, G.; Piccirillo, L.; Timbie, P.; Tucker, G. S.

    2004-01-01

    The Millimeter-wave Bolometric Interferometer (MBI) is a proposed ground-based instrument designed for a wide range of cosmological and astrophysical observations including studies of the polarization of the cosmic microwave background (CMB). MBI combines the advantages of two well-developed technologies - interferometers and bolometric detectors. Interferometers have many advantages over .filled-aperture telescopes and are particularly suitable for high resolution imaging. Cooled bolometers are the highest sensitivity detectors at millimeter and sub-millimeter wavelengths. The combination of these two technologies results in an instrument with both high sensitivity and high angular resolution.

  4. Radar illusion via metamaterials

    NASA Astrophysics Data System (ADS)

    Jiang, Wei Xiang; Cui, Tie Jun

    2011-02-01

    An optical illusion is an image of a real target perceived by the eye that is deceptive or misleading due to a physiological illusion or a specific visual trick. The recently developed metamaterials provide efficient approaches to generate a perfect optical illusion. However, all existing research on metamaterial illusions has been limited to theory and numerical simulations. Here, we propose the concept of a radar illusion, which can make the electromagnetic (EM) image of a target gathered by radar look like a different target, and we realize a radar illusion device experimentally to change the radar image of a metallic target into a dielectric target with predesigned size and material parameters. It is well known that the radar signatures of metallic and dielectric objects are significantly different. However, when a metallic target is enclosed by the proposed illusion device, its EM scattering characteristics will be identical to that of a predesigned dielectric object under the illumination of radar waves. Such an illusion device will confuse the radar, and hence the real EM properties of the metallic target cannot be perceived. We designed and fabricated the radar illusion device using artificial metamaterials in the microwave frequency, and good illusion performances are observed in the experimental results.

  5. Metamaterial for Radar Frequencies

    DTIC Science & Technology

    2012-09-01

    Circuit Board RAM Radar Absorbing Material RCS Radar Cross Section SNR Signal-to-Noise Ratio SNG Single-Negative SRR Split Ring Resonator...although some can be single-negative ( SNG ). DNG refers to material with simultaneous negative real parts of the permittivity r  and permeability

  6. Synchronization in multistatic radar

    NASA Astrophysics Data System (ADS)

    Jubrink, H. G.

    1993-08-01

    This report gives a summary of multistatic radar principles and synchronization methods. Different methods are described using direct and indirect synchronization. The report also presents a general review of synchronization methods for the future. Two LORAN C receivers have been analyzed for use as local reference oscillators in multistatic radar.

  7. The PROUST radar

    NASA Technical Reports Server (NTRS)

    Bertin, F.; Glass, M.; Ney, R.; Petitdidier, M.

    1986-01-01

    The Stratosphere-Troposphere (ST) radar called PROUST works at 935 MHz using the same klystron and antenna as the coherent-scatter radar. The use of this equipment for ST work has required some important modifications of the transmitting system and the development of receiving, data processing and acquisition (1984,1985) equipment. The modifications are discussed.

  8. Noncooperative rendezvous radar system

    NASA Technical Reports Server (NTRS)

    1974-01-01

    A fire control radar system was developed, assembled, and modified. The baseline system and modified angle tracking system are described along with the performance characteristics of the baseline and modified systems. Proposed changes to provide additional techniques for radar evaluation are presented along with flight test data.

  9. Polarization Radar Processing Technology

    DTIC Science & Technology

    1989-10-01

    Oi"C FILE ( J qII RADC-TR-89-144 In-House Report October 1989 AD-A215 242 POLARIZATION RADAR PROCESSING TECHNOLOGY Kenneth C. Stiefvater, Russell D...NO. NO. NO. ACCESSION NO. 62702F 4506 11 58 11. TITLE (Include Security Classification) POLARIZATION RADAR PROCESSING TECHNOLOGY 12. PERSONAL AUTHOR(S

  10. Determination of radar MTF

    SciTech Connect

    Chambers, D.

    1994-11-15

    The ultimate goal of the Current Meter Array (CMA) is to be able to compare the current patterns detected with the array with radar images of the water surface. The internal wave current patterns modulate the waves on the water surface giving a detectable modulation of the radar cross-section (RCS). The function relating the RCS modulations to the current patterns is the Modulation Transfer Function (MTF). By comparing radar images directly with co-located CMA measurements the MTF can be determined. In this talk radar images and CMA measurements from a recent experiment at Loch Linnhe, Scotland, will be used to make the first direct determination of MTF for an X and S band radar at low grazing angles. The technical problems associated with comparing radar images to CMA data will be explained and the solution method discussed. The results suggest the both current and strain rate contribute equally to the radar modulation for X band. For S band, the strain rate contributes more than the current. The magnitude of the MTF and the RCS modulations are consistent with previous estimates when the wind is blowing perpendicular to the radar look direction.

  11. Java Radar Analysis Tool

    NASA Technical Reports Server (NTRS)

    Zaczek, Mariusz P.

    2005-01-01

    Java Radar Analysis Tool (JRAT) is a computer program for analyzing two-dimensional (2D) scatter plots derived from radar returns showing pieces of the disintegrating Space Shuttle Columbia. JRAT can also be applied to similar plots representing radar returns showing aviation accidents, and to scatter plots in general. The 2D scatter plots include overhead map views and side altitude views. The superposition of points in these views makes searching difficult. JRAT enables three-dimensional (3D) viewing: by use of a mouse and keyboard, the user can rotate to any desired viewing angle. The 3D view can include overlaid trajectories and search footprints to enhance situational awareness in searching for pieces. JRAT also enables playback: time-tagged radar-return data can be displayed in time order and an animated 3D model can be moved through the scene to show the locations of the Columbia (or other vehicle) at the times of the corresponding radar events. The combination of overlays and playback enables the user to correlate a radar return with a position of the vehicle to determine whether the return is valid. JRAT can optionally filter single radar returns, enabling the user to selectively hide or highlight a desired radar return.

  12. Comparative Sensitivities of Gravitational Wave Detectors Based on Atom Interferometers and Light Interferometers

    NASA Technical Reports Server (NTRS)

    Baker, John G.; Thorpe, J. I.

    2012-01-01

    We consider a class of proposed gravitational wave detectors based on multiple atomic interferometers separated by large baselines and referenced by common laser systems. We compute the sensitivity limits of these detectors due to intrinsic phase noise of the light sources, non-inertial motion of the light sources, and atomic shot noise and compare them to sensitivity limits for traditional light interferometers. We find that atom interferometers and light interferometers are limited in a nearly identical way by intrinsic phase noise and that both require similar mitigation strategies (e.g. multiple arm instruments) to reach interesting sensitivities. The sensitivity limit from motion of the light sources is slightly different and favors the atom interferometers in the low-frequency limit, although the limit in both cases is severe. Whether this potential advantage outweighs the additional complexity associated with including atom interferometers will require further study.

  13. Equatorial MU Radar project

    NASA Astrophysics Data System (ADS)

    Yamamoto, Mamoru; Hashiguchi, H.; Tsuda, Toshitaka; Yamamoto, Masayuki

    Research Institute for Sustainable Humanosphere, Kyoto University (RISH) has been studying the atmosphere by using radars. The first big facility was the MU (Middle and Upper atmosphere) radar installed in Shiga, Japan in 1984. This is one of the most powerful and multi-functional radar, and is successful of revealing importance of atmospheric waves for the dynamical vertical coupling processes. The next big radar was the Equatorial Atmosphere Radar (EAR) installed at Kototabang, West Sumatra, Indonesia in 2001. The EAR was operated under close collaboration with LAPAN (Indonesia National Institute for Aeronautics and Space), and conducted the long-term continuous observations of the equatorial atmosphere/ionosphere for more than 10 years. The MU radar and the EAR are both utilized for inter-university and international collaborative research program for long time. National Institute for Polar Research (NIPR) joined EISCAT Scientific Association together with Nagoya University, and developed the PANSY radar at Syowa base in Antarctica as a joint project with University of Tokyo. These are the efforts of radar study of the atmosphere/ionosphere in the polar region. Now we can find that Japan holds a global network of big atmospheric/ionospheric radars. The EAR has the limitation of lower sensitivity compared with the other big radars shown above. RISH now proposes a plan of Equatorial MU Radar (EMU) that is to establish the MU-radar class radar next to the EAR. The EMU will have an active phased array antenna with the 163m diameter and 1055 cross-element Yagis. Total output power of the EMU will be more than 500kW. The EMU can detect turbulent echoes from the mesosphere (60-80km). In the ionosphere incoherent-scatter observations of plasma density, drift, and temperature would be possible. Multi-channel receivers will realize radar-imaging observations. The EMU is one of the key facilities in the project "Study of coupling processes in the solar-terrestrial system

  14. Spaceborne weather radar

    NASA Technical Reports Server (NTRS)

    Meneghini, Robert; Kozu, Toshiaki

    1990-01-01

    The present work on the development status of spaceborne weather radar systems and services discusses radar instrument complementarities, the current forms of equations for the characterization of such aspects of weather radar performance as surface and mirror-image returns, polarimetry, and Doppler considerations, and such essential factors in spaceborne weather radar design as frequency selection, scanning modes, and the application of SAR to rain detection. Attention is then given to radar signal absorption by the various atmospheric gases, rain drop size distribution and wind velocity determinations, and the characteristics of clouds, as well as the range of available estimation methods for backscattering, single- and dual-wavelength attenuation, and polarimetric and climatological characteristics.

  15. Micropower impulse radar imaging

    SciTech Connect

    Hall, M.S.

    1995-11-01

    From designs developed at the Lawrence Livermore National Laboratory (LLNL) in radar and imaging technologies, there exists the potential for a variety of applications in both public and private sectors. Presently tests are being conducted for the detection of buried mines and the analysis of civil structures. These new systems use a patented ultra-wide band (impulse) radar technology known as Micropower Impulse Radar (GPR) imaging systems. LLNL has also developed signal processing software capable of producing 2-D and 3-D images of objects embedded in materials such as soil, wood and concrete. My assignment while at LLNL has focused on the testing of different radar configurations and applications, as well as assisting in the creation of computer algorithms which enable the radar to scan target areas of different geometeries.

  16. Intelligent radar data processing

    NASA Astrophysics Data System (ADS)

    Holzbaur, Ulrich D.

    The application of artificial intelligence principles to the processing of radar signals is considered theoretically. The main capabilities required are learning and adaptation in a changing environment, processing and modeling information (especially dynamics and uncertainty), and decision-making based on all available information (taking its reliability into account). For the application to combat-aircraft radar systems, the tasks include the combination of data from different types of sensors, reacting to electronic counter-countermeasures, evaluation of how much data should be acquired (energy and radiation management), control of the radar, tracking, and identification. Also discussed are related uses such as monitoring the avionics systems, supporting pilot decisions with respect to the radar system, and general applications in radar-system R&D.

  17. Cascaded interferometers structure based on dual-pass Mach-Zehnder interferometer and Sagnac interferometer for dual-parameter sensing.

    PubMed

    Wang, Shun; Lu, Ping; Mao, Lili; Liu, Deming; Jiang, Shibin

    2015-01-26

    In this article, we propose and demonstrate a cascaded interferometers structure based on a dual-pass Mach-Zehnder interferometer (DP-MZI) and a Sagnac interferometer (SI) for simultaneous measurement of strain and lateral stress. The cascaded interferometers configuration consists of a SI structure following with a MZI setup. By inserting a section of polarization-maintaining photonic crystal fiber (PM-PCF) in the sensing loop of the SI structure, an inline interference between the two orthogonal polarization modes of PM-PCF, as well as the interference between the sensing arm and the reference arm of the DP-MZI, i.e., the cascaded interferometers with dual interference, are realized. Theoretical study shows that the reflection spectrum of such cascaded interferometers is consisted of two parts: the big spectrum envelope owing to the SI and the fine interference fringes as a result of the DP-MZI. Experimental results show that the SI achieves the sensitivity of lateral stress and strain 1.28 nm/kPa, 0.78 pm/µε, respectively, while the DP-MZI achieves -0.009 nm/kPa and 5.65 pm/µε, demonstrating the ability for dual parameters measurement with high accuracy.

  18. 4. VIEW NORTHEAST, radar tower (unknown function), prime search radar ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. VIEW NORTHEAST, radar tower (unknown function), prime search radar tower, emergency power building, and height finder radar tower - Fort Custer Military Reservation, P-67 Radar Station, .25 mile north of Dickman Road, east of Clark Road, Battle Creek, Calhoun County, MI

  19. 5. VIEW EAST, height finder radar towers, radar tower (unknown ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. VIEW EAST, height finder radar towers, radar tower (unknown function), prime search radar tower, operations building, and central heating plant - Fort Custer Military Reservation, P-67 Radar Station, .25 mile north of Dickman Road, east of Clark Road, Battle Creek, Calhoun County, MI

  20. Double-grating interferometer with a one-to-one correspondence with a Michelson interferometer.

    PubMed

    Xu, Yande; Sasaki, Osami; Suzuki, Takamasa

    2003-10-01

    We describe a double-grating interferometer that has a one-to-one correspondence with a Michelson interferometer. The half spatial periods of the gratings are equivalent to the wavelengths of the interferometer. The widths of the interference fringes can be changed easily. The intensity distribution of the interference pattern is independent of the wavelength of the light source used. The surface profile of an object can be measured because two interference beams can coincide precisely on the image plane of the object. The measuring range is much larger than that of a Michelson interferometer.

  1. Improved double-pass michelson interferometer

    NASA Technical Reports Server (NTRS)

    Schindler, R. A.

    1978-01-01

    Interferometer design separates beams by offsetting centerlines of cat's-eye retroreflectors vertically rather than horizontally. Since beam splitter is insensitive to minimum-thickness condition in this geometry, relatively-low-cost, optically flat plate can be used.

  2. Naturally stable Sagnac-Michelson nonlinear interferometer.

    PubMed

    Lukens, Joseph M; Peters, Nicholas A; Pooser, Raphael C

    2016-12-01

    Interferometers measure a wide variety of dynamic processes by converting a phase change into an intensity change. Nonlinear interferometers, making use of nonlinear media in lieu of beamsplitters, promise substantial improvement in the quest to reach the ultimate sensitivity limits. Here we demonstrate a new nonlinear interferometer utilizing a single parametric amplifier for mode mixing-conceptually, a nonlinear version of the conventional Michelson interferometer with its arms collapsed together. We observe up to 99.9% interference visibility and find evidence for noise reduction based on phase-sensitive gain. Our configuration utilizes fewer components than previous demonstrations and requires no active stabilization, offering new capabilities for practical nonlinear interferometric-based sensors.

  3. Naturally stable Sagnac-Michelson nonlinear interferometer

    NASA Astrophysics Data System (ADS)

    Lukens, Joseph M.; Peters, Nicholas A.; Pooser, Raphael C.

    2016-12-01

    Interferometers measure a wide variety of dynamic processes by converting a phase change into an intensity change. Nonlinear interferometers, making use of nonlinear media in lieu of beamsplitters, promise substantial improvement in the quest to reach the ultimate sensitivity limits. Here we demonstrate a new nonlinear interferometer utilizing a single parametric amplifier for mode mixing---conceptually, a nonlinear version of the conventional Michelson interferometer with its arms collapsed together. We observe up to 99.9\\% interference visibility and find evidence for noise reduction based on phase-sensitive gain. Our configuration utilizes fewer components than previous demonstrations and requires no active stabilization, offering new capabilities for practical nonlinear interferometric-based sensors.

  4. The effect of rotations on Michelson interferometers

    NASA Astrophysics Data System (ADS)

    Maraner, Paolo

    2014-11-01

    In the contest of the special theory of relativity, it is shown that uniform rotations induce a phase shift in Michelson interferometers. The effect is second order in the ratio of the interferometer's speed to the speed of light, further suppressed by the ratio of the interferometer's arms length to the radius of rotation and depends on the interferometer's position in the co-rotating frame. The magnitude of the phase shift is just beyond the sensitivity of turntable rotated optical resonators used in present tests of Lorentz invariance. It grows significantly large in Earth's rotated kilometer-scale Fabry-Perot enhanced interferometric gravitational-wave detectors where it appears as a constant bias. The effect can provide the means of sensing center and radius of rotations.

  5. Naturally stable Sagnac–Michelson nonlinear interferometer

    DOE PAGES

    Lukens, Joseph M.; Peters, Nicholas A.; Pooser, Raphael C.

    2016-11-16

    Interferometers measure a wide variety of dynamic processes by converting a phase change into an intensity change. Nonlinear interferometers, making use of nonlinear media in lieu of beamsplitters, promise substantial improvement in the quest to reach the ultimate sensitivity limits. Here we demonstrate a new nonlinear interferometer utilizing a single parametric amplifier for mode mixing conceptually, a nonlinear version of the conventional Michelson interferometer with its arms collapsed together. We observe up to 99.9% interference visibility and find evidence for noise reduction based on phase-sensitive gain. As a result, our configuration utilizes fewer components than previous demonstrations and requires nomore » active stabilization, offering new capabilities for practical nonlinear interferometric-based sensors.« less

  6. Naturally stable Sagnac–Michelson nonlinear interferometer

    SciTech Connect

    Lukens, Joseph M.; Peters, Nicholas A.; Pooser, Raphael C.

    2016-11-16

    Interferometers measure a wide variety of dynamic processes by converting a phase change into an intensity change. Nonlinear interferometers, making use of nonlinear media in lieu of beamsplitters, promise substantial improvement in the quest to reach the ultimate sensitivity limits. Here we demonstrate a new nonlinear interferometer utilizing a single parametric amplifier for mode mixing conceptually, a nonlinear version of the conventional Michelson interferometer with its arms collapsed together. We observe up to 99.9% interference visibility and find evidence for noise reduction based on phase-sensitive gain. As a result, our configuration utilizes fewer components than previous demonstrations and requires no active stabilization, offering new capabilities for practical nonlinear interferometric-based sensors.

  7. Polymeric slot waveguide interferometer for sensor applications.

    PubMed

    Hiltunen, Marianne; Hiltunen, Jussi; Stenberg, Petri; Aikio, Sanna; Kurki, Lauri; Vahimaa, Pasi; Karioja, Pentti

    2014-03-24

    A refractive index sensor based on slot waveguide Young interferometer was developed in this work. The interferometer was fabricated on a polymer platform and operates at a visible wavelength of 633 nm. The phase shift of the interference pattern was measured with various concentrations of glucose-water solutions, utilizing both TE and TM polarization states. The sensor was experimentally observed to detect a refractive index difference of 6.4 × 10(-6) RIU. Furthermore, the slot Young interferometer was found to compensate for temperature variations. The results of this work demonstrate that high performance sensing capability can be obtained with a polymeric slot Young interferometer, which can be fabricated by a simple molding process.

  8. Spider-like lightning observation using VHF broadband digital interferometer

    NASA Astrophysics Data System (ADS)

    Nakamura, Y.; Murata, K.; Morimoto, T.; Ushio, T.; Kawasaki, Z.

    2008-12-01

    Lightning Research Group of Osaka University (LRG-OU) has been developing the VHF broadband digital interferometer since 1995. This is a two- (2D) and three-dimensional (3D) VHF source mapping system for electromagnetic (EM) waves emitted by lightning discharge progression based on a unique technique of the broadband digital interferometry. LRG-OU carried out field observation campaigns with the VHF broadband digital interferometers during monsoon seasons in Darwin, Australia. Through these campaigns a lot of lightning channels were visualized. The bi-directional leader progression, possible charge distribution related to the leader initiation, and the speed of the leader propagation are studied by the 3D imaging. At 0943:13 UT on 13 December, 2006, a spider-like cloud-to-cloud (CC) flash is recorded. In this flash, 4 groups of leaders are clearly visualized simultaneously. All leaders initiate from similar location, but develop to 4 different directions. One of these goes up to over 9km height, while the others progress horizontally between 2 and 5 km high. According to the weather radar observations by BOM, the bright band is noticeable at about 5 km high. It means the lower leaders progress under "melting snow" layer and positive charges exist in this region. It is considered that the lower leaders develop as long as 8 km horizontally neutralizing freckled positive charge. The leaders resembling dart leaders that propagate through the exact same channel as previous leader are also seen in this flash. The precedent leader proceeds with a speed of about 104 m/s, and then subsequent leaders proceed at a speed of about 106 m/s. In the presentation, we would like to discuss about the details of this spider-like CC flash.

  9. Millimeter-wave/THz FMCW radar techniques for sensing applications

    NASA Astrophysics Data System (ADS)

    Mirando, D. Amal; Higgins, Michael D.; Wang, Fenggui; Petkie, Douglas T.

    2016-10-01

    Millimeter-wave and terahertz continuous-wave radar systems have been used to measure physiological signatures for biometric applications and for a variety of non-destructive evaluation applications, such as the detection of defects in materials. Sensing strategies for the simplest homodyne systems, such as a Michelson Interferometer, can be enhanced by using Frequency Modulated Continuous Wave (FMCW) techniques. This allows multiple objects or surfaces to be range resolved while monitoring the phase of the signal in a particular range bin. We will discuss the latest developments in several studies aimed at demonstrating how FMCW techniques can enhance mmW/THz sensing applications.

  10. Mathematical interpretation of radial shearing interferometers.

    PubMed

    Malacara, D

    1974-08-01

    The procedure for computing a radial shearing interferometric pattern is given. The interferometric pattern is analyzed to obtain the wavefront shape. Restricting the discussion to wavefronts having rotational symmetry, we give two different methods of finding the wavefront. One approach is to scan along a diameter of the interferometric pattern and the other is to examine the shape of the fringes. The relative sensitivity of a radial shearing interferometer with respect to that of a Twyman-Green interferometer is also analyzed.

  11. Single and double superimposing interferometer systems

    DOEpatents

    Erskine, David J.

    2000-01-01

    Interferometers which can imprint a coherent delay on a broadband uncollimated beam are described. The delay value can be independent of incident ray angle, allowing interferometry using uncollimated beams from common extended sources such as lamps and fiber bundles, and facilitating Fourier Transform spectroscopy of wide angle sources. Pairs of such interferometers matched in delay and dispersion can measure velocity and communicate using ordinary lamps, wide diameter optical fibers and arbitrary non-imaging paths, and not requiring a laser.

  12. The WIND-HAARP-HIPAS Interferometer Experiment

    DTIC Science & Technology

    1999-04-22

    of HAARP and HIPAS are sufficient to modify the intervening plasma through heating and affect the fringe pattern. Repeating experiments of this kind...Naval Research Laboratory Washington, DC 20375-5320 NRL/MR/6750--99-8349 The WIND- HAARP -HIPAS Interferometer Experiment P. RODRIGUEZ AND M. J...1999 3. REPORT TYPE AND DATES COVERED Interim Report 4. TITLE AND SUBTITLE The WIND- HAARP -HIPAS Interferometer Experiment 5. FUNDING NUMBERS JO

  13. Nonlinear Michelson interferometer for improved quantum metrology

    NASA Astrophysics Data System (ADS)

    Luis, Alfredo; Rivas, Ángel

    2015-08-01

    We examine quantum detection via a Michelson interferometer embedded in a gas with Kerr nonlinearity. This nonlinear interferometer is illuminated by pulses of classical light. This strategy combines the robustness against practical imperfections of classical light with the improvement provided by nonlinear processes. Regarding ultimate quantum limits, we stress that, as a difference with linear schemes, the nonlinearity introduces pulse duration as a new variable into play along with the energy resources.

  14. Simple phase-shifting lateral shearing interferometer.

    PubMed

    Mihaylova, Emilia; Whelan, Maurice; Toal, Vincent

    2004-06-01

    A phase-shifting electronic speckle pattern shearing interferometer with a very simple shearing device is proposed. Two partially reflective glass plates are used to introduce the shear in this new interferometer. The reflection coefficients of the coatings on the two plates are 0.3 and 0.7. The distance between the two glass plates controls the size of the shear. The proposed new interferometric system is simple, flexible, and low cost.

  15. Radar remote sensing in biology

    USGS Publications Warehouse

    Moore, Richard K.; Simonett, David S.

    1967-01-01

    The present status of research on discrimination of natural and cultivated vegetation using radar imaging systems is sketched. The value of multiple polarization radar in improved discrimination of vegetation types over monoscopic radars is also documented. Possible future use of multi-frequency, multi-polarization radar systems for all weather agricultural survey is noted.

  16. Spaceborne meteorological radar studies

    NASA Technical Reports Server (NTRS)

    Meneghini, R.

    1988-01-01

    Various radar designs and methods are studied for the estimation of rainfall parameters from space. An immediate goal is to support the development of the spaceborne radar that has been proposed for the Tropical Rain Measuring Mission (TRMM). The effort is divided into two activities: a cooperative airborne rain measuring experiment with the Radio Research Laboratory of Japan (RRL), and the modelling of spaceborne weather radars. An airborne rain measuring experiment was conducted at Wallops Flight Facility in 1985 to 1986 using the dual-wavelength radar/radiometer developed by RRL. The data are presently being used to test a number of methods that are relevant to spaceborne weather radars. An example is shown of path-averaged rain rates as estimated from three methods: the standard reflectivity rain rate method (Z-R), a dual-wavelength method, and a surface reference method. The results from the experiment shows for the first time the feasibility of using attenuation methods from space. The purposes of the modelling are twofold: to understand in a quantitative manner the relationships between a particular radar design and its capability for estimating precipitation parameters and to help devise and test new methods. The models are being used to study the impact of various TRMM radar designs on the accuracy of rain rate estimation as well as to test the performance of range-profiling algorithms, the mirror-image method, and some recently devised graphical methods for the estimation of the drop size distribution.

  17. The VLA Atmospheric Phase Interferometer

    NASA Astrophysics Data System (ADS)

    Morris, Keith

    2014-05-01

    The Atmospheric Phase Interferometer (API) is a two-element atmospheric seeing monitor located at the Very Large Array (VLA) site. The instrument measures turbulent refractive index variation through the atmosphere by examining phase differences in a satellite beacon signal detected at two (or more) antennas. With this measurement, the VLA scheduling software is able to consider atmospheric stability when determining which frequency observation to schedule next. We are in the process of extending this two-element interferometer to four elements, which will allow us to measure the turbulence in two dimensions and at multiple length scales. This thesis will look at some statistical properties of turbulence, the effects of atmospheric stability on radio interferometric observations, and discuss details of the instrument and the data that it collects. The thesis will also cover some techniques and principles of signal processing, and an analysis of some data from the instrument. The results demonstrate that other surface atmospheric variables (e.g. windspeed, water vapor pressure) show the same structure function exponent as the atmospheric phase fluctuations. In particular, the structure functions of water vapor partial pressure and wind speed show the same exponent as the phase. Though the agreement between meteorological variables and atmospheric phase is scientifically satisfying, these surface measurements are not nearly as sensitive as the API saturation phase measurement, and therefore cannot be used to schedule telescope time in its stead. What is informative about these results is that the similar structure functions for API and meteorological data are detecting reinforce the claim that both measurements represent turbulent transport, and not instrumental noise. Data from the instrument reveals that measurements are consistent with both Kolmogorov turbulence theory, and with prior observations. The API predominately measures three-dimensional isotropic

  18. Glaciological Applications of Terrestrial Radar Interferometry

    NASA Astrophysics Data System (ADS)

    Voytenko, D.; Dixon, T. H.

    2014-12-01

    Terrestrial Radar Interferometry (TRI) is a relatively new ground-based technique that combines the precision and spatial resolution of InSAR with the temporal resolution of GPS. Although TRI can be applied to a variety of fields including bridge and landslide monitoring, it is ideal for studies of the highly dynamic terminal zones of marine-terminating glaciers. Our TRI instrument is the Gamma Portable Radar Interferometer, which operates at 17.2 GHz (1.74 cm wavelength), has two receiving antennas for DEM generation, and generates amplitude and phase images at minute-scale sampling rates. Here we review preliminary results from Breiðamerkurjökull in Iceland and Helheim and Jakobshavn in Greenland. We show that the high sampling rate of the TRI can be used to observe velocity variations at the glacier terminus associated with calving, and the spatial distribution of tidal forcing. Velocity uncertainties, mainly due to atmospheric effects, are typically less than 0.05 m/d. Additionally, iceberg tracking using the amplitude imagery may provide insight into ocean currents near the terminus when fjord or lagoon conditions permit.

  19. Radar applications overview

    NASA Astrophysics Data System (ADS)

    Greenspan, Marshall

    1996-06-01

    During the fifty years since its initial development as a means of providing early warning of airborne attacks against allied countries during World War II, radar systems have developed to the point of being highly mobile and versatile systems capable of supporting a wide variety of remote sensing applications. Instead of being tied to stationary land-based sites, radar systems have found their way into highly mobile land vehicles as well as into aircraft, missiles, and ships of all sizes. Of all these applications, however, the most exciting revolution has occurred in the airborne platform arena where advanced technology radars can be found in all shapes and sizes...ranging from the large AWACS and Joint STARS long range surveillance and targeting systems to small millimeter wave multi-spectral sensors on smart weapons that can detect and identify their targets through the use of highly sophisticated digital signal processing hardware and software. This paper presents an overview of these radar applications with the emphasis on modern airborne sensors that span the RF spectrum. It will identify and describe the factors that influence the parameters of low frequency and ultra wide band radars designed to penetrate ground and dense foliage environments and locate within them buried mines, enemy armor, and other concealed or camouflaged weapons of war. It will similarly examine the factors that lead to the development of airborne radar systems that support long range extended endurance airborne surveillance platforms designed to detect and precision-located both small high speed airborne threats as well as highly mobile time critical moving and stationary surface vehicles. The mission needs and associated radar design impacts will be contrasted with those of radar systems designed for high maneuverability rapid acquisition tactical strike warfare platforms, and shorter range cued air-to-surface weapons with integral smart radar sensors.

  20. Radar frequency radiation

    NASA Astrophysics Data System (ADS)

    Malowicki, E.

    1981-11-01

    A method is presented for the determination of radar frequency radiation power densities that the PAVE PAWS radar system could produce in its air and ground environment. The effort was prompted by the concern of the people in the vicinity of OTIS AFB MA and BEALE AFB CA about the possible radar frequency radiation hazard of the PAVE PAWS radar. The method is based on the following main assumptions that: (a) the total field can be computed as the vector summation of the individual fields due to each antenna element; (b) the individual field can be calculated using distances for which the field point is in the far field of the antenna element. An RFR computer program was coded for the RADC HE 6180 digital computer and exercised to calculate the radiation levels in the air and ground space for the present baseline and the possible Six DB and 10 DB growth systems of the PAVE PAWS radar system at OTIS AFB MA. The average radiation levels due to the surveillance fence were computed for three regions: in the air space in front of the radar, at the radar hazard fence at OTIS AFB MA and at representative ground points in the OTIS AFB vicinity. It was concluded that the radar frequency radiation of PAVE PAWS does not present a hazard to personnel provided there is no entry to the air hazard zone or to the area within the hazard fence. The method developed offers a cost effective way to determine radiation levels from a phased array radar especially in the near field and transition regions.

  1. High-resolution interferometric radar images of equatorial spread F scattering structures using Capon's method

    NASA Astrophysics Data System (ADS)

    Zewdie, G. K.; Rodrigues, F. S.; Paula, E. R.

    2015-12-01

    Coherent backscatter radar imaging techniques use measurements made by multiple antenna baselines (visibility estimates) to infer the spatial distribution of the scatterers (brightness function) responsible for the observed echoes. It has been proposed that the Capon method for spectral estimation can be used for high-resolution estimation of the brightness distribution. We investigate the application of the Capon method to measurements made by a small (7-baseline) 30 MHz ionospheric coherent backscatter radar interferometer in Sao Luis, Brazil. The longest baseline of the interferometer is only 15 times the wavelength of radar signal (10 m), and the ionospheric radar soundings have been made using only 4-8 kW transmitters. Nevertheless, we have been able to obtain high-resolution (kilometric scales in the zonal direction) images of scattering structures during equatorial spread F (ESF) events over a wide field of view (+/- 10 degrees off zenith). We will present numerical simulations demonstrating the performance of the technique for the Sao Luis radar setup as well as results of the Capon technique applied to actual measurements. We will discuss the behavior of the ESF scattering structures as seen in the Capon images. The high-resolution images can assist our interpretation of plasma instabilities in the equatorial ionosphere and serve to test our ability to model the behavior of ionospheric irregularities during space weather events such as those associated with ESF.

  2. A microprogrammable radar controller

    NASA Technical Reports Server (NTRS)

    Law, D. C.

    1986-01-01

    The Wave Propagation Lab. has completed the design and construction of a microprogrammable radar controller for atmospheric wind profiling. Unlike some radar controllers using state machines or hardwired logic for radar timing, this design is a high speed programmable sequencer with signal processing resources. A block diagram of the device is shown. The device is a single 8 1/2 inch by 10 1/2 inch printed circuit board and consists of three main subsections: (1) the host computer interface; (2) the microprogram sequencer; and (3) the signal processing circuitry. Each of these subsections are described in detail.

  3. Radar investigation of asteroids

    NASA Technical Reports Server (NTRS)

    Ostro, S. J.

    1981-01-01

    Efforts were focused on: (1) acquisition of radar data at Arecibo; (2) examination of raw data; (3) reduction of the unmodulated data to background-free, calibrated spectra; (4) integration and coherent analyses of the phase-coded data; and (5) calculation of Doppler shifts and preliminary values for echo limb-to-limb bandwidths, radar cross sections, and circular polarization ratios. Asteroids observed to data have radar properties distinct from those of the rocky terrestrial planets and those of the icy Galilean satellites.

  4. Radar investigation of asteroids

    NASA Technical Reports Server (NTRS)

    Ostro, S. J.

    1981-01-01

    Software to support all stages of asteroid radar observation and data analysis is developed. First-order analysis of all data in hand is complete. Estimates of radar cross sections, circular polarization ratios, and limb-to-limb echo spectral bandwidths for asteroids 7 Iris, 16 Psyche, 97 Klotho, 1862 Apollo, and 1915 Quetzalcoatl are reported. Radar observations of two previously unobserved asteroids were conducted. An Aten asteroid, 2100 Ra-Shalom, with the smallest known semimajor axis (0.83) was detected. Preliminary data reduction indicates a circular polarization ratio comparable to those of Apollo, Quetzalcoatl, and Toro.

  5. Radar investigation of asteroids

    NASA Technical Reports Server (NTRS)

    Ostro, S. J.

    1984-01-01

    The initial radar observations of the mainbelt asteroids 9 Metis, 27 Euterpe, and 60 Echo are examined. For each target, data are taken simultaneously in the same sense of circular polarization as transmitted as well as in the opposite (OC) sense. Estimates of the radar cross sections provide estimates of the circular polarization ratio, and the normalized OC radar cross section. The circular polarization ratio, is comparable to values measured for other large S type asteroids and for a few much smaller, Earth approaching objects, most of the echo is due to single reflection backscattering from smooth surface elements.

  6. Radar investigation of asteroids

    NASA Astrophysics Data System (ADS)

    Ostro, S. J.

    1981-11-01

    Software to support all stages of asteroid radar observation and data analysis is developed. First-order analysis of all data in hand is complete. Estimates of radar cross sections, circular polarization ratios, and limb-to-limb echo spectral bandwidths for asteroids 7 Iris, 16 Psyche, 97 Klotho, 1862 Apollo, and 1915 Quetzalcoatl are reported. Radar observations of two previously unobserved asteroids were conducted. An Aten asteroid, 2100 Ra-Shalom, with the smallest known semimajor axis (0.83) was detected. Preliminary data reduction indicates a circular polarization ratio comparable to those of Apollo, Quetzalcoatl, and Toro.

  7. Radar Remote Sensing

    NASA Technical Reports Server (NTRS)

    Rosen, Paul A.

    2012-01-01

    This lecture was just a taste of radar remote sensing techniques and applications. Other important areas include Stereo radar grammetry. PolInSAR for volumetric structure mapping. Agricultural monitoring, soil moisture, ice-mapping, etc. The broad range of sensor types, frequencies of observation and availability of sensors have enabled radar sensors to make significant contributions in a wide area of earth and planetary remote sensing sciences. The range of applications, both qualitative and quantitative, continue to expand with each new generation of sensors.

  8. Topography of the lunar poles from radar interferometry: a survey of cold trap locations.

    PubMed

    Margot, J L; Campbell, D B; Jurgens, R F; Slade, M A

    1999-06-04

    Detailed topographic maps of the lunar poles have been obtained by Earth-based radar interferometry with the 3.5-centimeter wavelength Goldstone Solar System Radar. The interferometer provided maps 300 kilometers by 1000 kilometers of both polar regions at 150-meter spatial resolution and 50-meter height resolution. Using ray tracing, these digital elevation models were used to locate regions that are in permanent shadow from solar illumination and may harbor ice deposits. Estimates of the total extent of shadowed areas poleward of 87.5 degrees latitude are 1030 and 2550 square kilometers for the north and south poles, respectively.

  9. Radar Scattering from the Summer Polar Mesosphere: Theory and Observations

    NASA Astrophysics Data System (ADS)

    Cho, John Yungdo Nagamichi

    The anomalously large radar reflectivities observed in the summer polar mesosphere have eluded satisfactory explanation until now. We propose that the following chain of causality is responsible for the so-called polar mesosphere summer echoes (PMSE): The uniquely low temperatures in the summer mesopause produce ice aerosols. Because the aerosols exist in a plasma, they become electrically charged. The ambient electrons become coupled to the aerosols through electric fields and their effective diffusivity is retarded due to the large size of the aerosols. The reduction in diffusivity allows electron density inhomogeneities to be maintained at the radar Bragg scales. The radar waves are then scattered by the inhomogeneities. We support the above concept by developing a quantitative theory of ambipolar diffusion in the mesosphere. We then apply the results to isotropic turbulence and Fresnel radar scatter to show that the observed radar reflectivities can be explained by the theory. We show that the presence of realistic charged aerosols are sufficient to explain PMSE. We also show that dressed aerosol radar scatter, proposed by others as a generation mechanism for PMSE, can only apply to echoes detected by UHF radars. We present data taken with the Sondrestrom 1.29-GHz radar, which we believe to be the first PMSE event observed above one gigahertz, and attribute it to dressed aerosol scatter. In the summer of 1991, we used the Cornell University portable radar interferometer (CUPRI) to observe the mesosphere while rockets carrying in situ sensors were flown through two PMSE occurrences and a noctilucent cloud/PMSE event. We present a selection of first results from this campaign (NLC-91). The first simultaneous height comparison between noctilucent clouds and PMSE show that the radar scattering region was near or slightly above the visible cloud layer. We also infer from aspect sensitivity measurements and Doppler spectrograms that there were two distinct types of

  10. Studies on Radar Sensor Networks

    DTIC Science & Technology

    2007-08-08

    through-foliage target detection using UWB radar sensor network based on real-world data; 2. Foliage clutter modeling using UWB radars; 3. Outdoor UWB...channel modeling based on field data; 4. Multi-target detection using radar sensor networks (theoretical studies); 5. SVD-QR and graph theory for MIMO...Superimposed code based channel assignment in multi-radio multi-channel wireless mesh networks. 15. SUBJECT TERMS Radar Sensor Network, UWB Radar, Sense

  11. Keck Interferometer Nuller science highlights

    NASA Astrophysics Data System (ADS)

    Mennesson, Bertrand; Millan-Gabet, Rafael; Colavita, M. M.; Serabyn, E.; Hinz, P.; Kuchner, M.; Liu, W.; Barry, R.; Stark, C.; Ragland, S.; Woillez, J.; Traub, W.; Absil, O.; Defrère, Denis; Augereau, J. C.; Lebreton, J.

    2012-07-01

    We report here on some of the major astronomical observations obtained by the Keck Interferometer Nuller (KIN), the high dynamic range instrument recombining the Keck Telescopes at wavelengths of 8 to 13 microns. A few science targets were observed during the commissioning phase (2004-2007). These early observations aimed at demonstrating the KIN’s ability to spatially resolve and characterize circumstellar dust emission around a variety of targets, ranging from evolved stars to young debris disks. Science operations started then in 2008 with the more demanding KIN exozodi key science programs, augmented by observations of YSOs and hot debris disks between 2009 and 2011. The last KIN observations were gathered in 2011B, and the interpretation of some of the results depicted here is still preliminary (exo-zodi survey) or pending (complicated behavior observed in YSOs). We discuss in particular the initial results of the KIN’s exo-zodi observations, which targeted a total of 40 nearby main sequence single stars. We look for trends in this sample, searching for possible correlations between the measured KIN excesses and basic stellar properties such as spectral type or the presence of dust inferred from separate observations.

  12. Achromatic self-referencing interferometer

    DOEpatents

    Feldman, Mark

    1994-01-01

    A self-referencing Mach-Zehnder interferometer for accurately measuring laser wavefronts over a broad wavelength range (for example, 600 nm to 900 nm). The apparatus directs a reference portion of an input beam to a reference arm and a measurement portion of the input beam to a measurement arm, recombines the output beams from the reference and measurement arms, and registers the resulting interference pattern ("first" interferogram) at a first detector. Optionally, subportions of the measurement portion are diverted to second and third detectors, which respectively register intensity and interferogram signals which can be processed to reduce the first interferogram's sensitivity to input noise. The reference arm includes a spatial filter producing a high quality spherical beam from the reference portion, a tilted wedge plate compensating for off-axis aberrations in the spatial filter output, and mirror collimating the radiation transmitted through the tilted wedge plate. The apparatus includes a thermally and mechanically stable baseplate which supports all reference arm optics, or at least the spatial filter, tilted wedge plate, and the collimator. The tilted wedge plate is mounted adjustably with respect to the spatial filter and collimator, so that it can be maintained in an orientation in which it does not introduce significant wave front errors into the beam propagating through the reference arm. The apparatus is polarization insensitive and has an equal path length configuration enabling measurement of radiation from broadband as well as closely spaced laser line sources.

  13. Achromatic self-referencing interferometer

    DOEpatents

    Feldman, M.

    1994-04-19

    A self-referencing Mach-Zehnder interferometer is described for accurately measuring laser wavefronts over a broad wavelength range (for example, 600 nm to 900 nm). The apparatus directs a reference portion of an input beam to a reference arm and a measurement portion of the input beam to a measurement arm, recombines the output beams from the reference and measurement arms, and registers the resulting interference pattern ([open quotes]first[close quotes] interferogram) at a first detector. Optionally, subportions of the measurement portion are diverted to second and third detectors, which respectively register intensity and interferogram signals which can be processed to reduce the first interferogram's sensitivity to input noise. The reference arm includes a spatial filter producing a high quality spherical beam from the reference portion, a tilted wedge plate compensating for off-axis aberrations in the spatial filter output, and mirror collimating the radiation transmitted through the tilted wedge plate. The apparatus includes a thermally and mechanically stable baseplate which supports all reference arm optics, or at least the spatial filter, tilted wedge plate, and the collimator. The tilted wedge plate is mounted adjustably with respect to the spatial filter and collimator, so that it can be maintained in an orientation in which it does not introduce significant wave front errors into the beam propagating through the reference arm. The apparatus is polarization insensitive and has an equal path length configuration enabling measurement of radiation from broadband as well as closely spaced laser line sources. 3 figures.

  14. Laser Radar Animation

    NASA Video Gallery

    Laser and radar instruments aboard NASA aircraft provide measurements of the snow and ice surface and down to the bedrock under the ice. Lasers, with a shorter wavelength, measure the surface eleva...

  15. Multispectral imaging radar

    NASA Technical Reports Server (NTRS)

    Porcello, L. J.; Rendleman, R. A.

    1972-01-01

    A side-looking radar, installed in a C-46 aircraft, was modified to provide it with an initial multispectral imaging capability. The radar is capable of radiating at either of two wavelengths, these being approximately 3 cm and 30 cm, with either horizontal or vertical polarization on each wavelength. Both the horizontally- and vertically-polarized components of the reflected signal can be observed for each wavelength/polarization transmitter configuration. At present, two-wavelength observation of a terrain region can be accomplished within the same day, but not with truly simultaneous observation on both wavelengths. A multiplex circuit to permit this simultaneous observation has been designed. A brief description of the modified radar system and its operating parameters is presented. Emphasis is then placed on initial flight test data and preliminary interpretation. Some considerations pertinent to the calibration of such radars are presented in passing.

  16. Radar investigation of asteroids

    NASA Technical Reports Server (NTRS)

    Ostro, S. J.

    1983-01-01

    For 80 Sappho, 356 Liguria, 694 Ekard, and 2340 Hathor, data were taken simultaneously in the same sense of circular polarization as transmitted (SC) as well as in the opposite (OC) sense. Graphs show the average OC and SC radar echo power spectra soothed to a resolution of EFB Hz and plotted against Doppler frequency. Radar observations of the peculiar object 2201 Oljato reveal an unusual set of echo power spectra. The albedo and polarization ratio remain fairly constant but the bandwidths range from approximately 0.8 Hz to 1.4 Hz and the spectral shapes vary dramatically. Echo characteristics within any one date's approximately 2.5-hr observation period do not fluctuate very much. Laboratory measurements of the radar frequency electrical properties of particulate metal-plus-silicate mixtures can be combined with radar albedo estimates to constrain the bulk density and metal weight, fraction in a hypothetical asteroid regolith having the same particle size distribution as lab samples.

  17. Comparison of Atom Interferometers and Light Interferometers as Space-Based Gravitational Wave Detectors

    NASA Technical Reports Server (NTRS)

    Baker, John G.

    2012-01-01

    We consider a class of proposed gravitational wave detectors based on multiple atomic interferometers separated by large baselines and referenced by common laser systems. We compute the sensitivity limits of these detectors due to intrinsic phase noise of the light sources, non-inertial motion of the light sources, and atomic shot noise and compare them to sensitivity limits for traditional light interferometers. We find that atom interferometers and light interferometers are limited in a nearly identical way by intrinsic phase noise and that both require similar mitigation strategies (e.g. multiple arm instruments) to reach interesting sensitivities. The sensitivity limit from motion of the light sources is slightly different and favors the atom interferometers in the low-frequency limit, although the limit in both cases is severe.

  18. Comparison of atom interferometers and light interferometers as space-based gravitational wave detectors.

    PubMed

    Baker, John G; Thorpe, J I

    2012-05-25

    We consider a class of proposed gravitational-wave detectors based on multiple atomic interferometers separated by large baselines and referenced by common laser systems. We compute the sensitivity limits of these detectors due to intrinsic phase noise of the light sources, noninertial motion of the light sources, and atomic shot noise and compare them to sensitivity limits for traditional light interferometers. We find that atom interferometers and light interferometers are limited in a nearly identical way by intrinsic phase noise and that both require similar mitigation strategies (e.g., multiple-arm instruments) to reach interesting sensitivities. The sensitivity limit from motion of the light sources is slightly different and, in principle, favors the atom interferometers in the low-frequency limit, although the limit in both cases is severe.

  19. GEOS-3 ocean current investigation using radar altimeter profiling. [Gulf Stream surface topography

    NASA Technical Reports Server (NTRS)

    Leitao, C. D.; Huang, N. E.; Parra, C. G.

    1978-01-01

    Both quasi-stationary and dynamic departures from the marine geoid were successfully detected using altitude measurements from the GEOS-3 radar altimeter. The quasi-stationary departures are observed either as elevation changes in single pass profiles across the Gulf Stream or at the crowding of contour lines at the western and northern areas of topographic maps generated using altimeter data spanning one month or longer. Dynamic features such as current meandering and spawned eddies can be monitored by comparing monthly mean maps. Comparison of altimeter inferred eddies with IR detected thermal rings indicates agreement of the two techniques. Estimates of current velocity are made using derived slope estimates in conjunction with the geostrophic equation.

  20. Radar Cross Section Measurements

    DTIC Science & Technology

    1986-09-30

    Radar 54 17. Measured Range Sidelobe Performance of Chirp Radar 56 18. Range and Cross Range Image of Target Dror.’ŕ Vehicle 57 19. Incoherent rms...the measured range resolution, 4.9 in, closely agrees with the theoretical performance for this weighting. The measured range sidelobe performance...Interval 4.89in. 2% kHz 300 kHz 310 kHz (b) Expanded Scale + 5 ft from Target Figure 17. Measured Range Sidelobe Performance of

  1. Downhole pulse radar

    DOEpatents

    Chang, Hsi-Tien

    1987-09-28

    A borehole logging tool generates a fast rise-time, short duration, high peak-power radar pulse having broad energy distribution between 30 MHz and 300 MHz through a directional transmitting and receiving antennas having barium titanate in the electromagnetically active region to reduce the wavelength to within an order of magnitude of the diameter of the antenna. Radar returns from geological discontinuities are sampled for transmission uphole. 7 figs.

  2. Downhole pulse radar

    DOEpatents

    Chang, Hsi-Tien

    1989-01-01

    A borehole logging tool generates a fast rise-time, short duration, high peak-power radar pulse having broad energy distribution between 30 MHz and 300 MHz through a directional transmitting and receiving antennas having barium titanate in the electromagnetically active region to reduce the wavelength to within an order of magnitude of the diameter of the antenna. Radar returns from geological discontinuities are sampled for transmission uphole.

  3. Airborne MIMO GMTI Radar

    DTIC Science & Technology

    2011-03-31

    applications [1], [2], [3], [4]. [5]. [6]. [7]. [8]. [9]. [10]. [11]. [12]. Conventional phased array radars form a single coherent transmit beam and...intentionally left blank. 1. INTRODUCTION Conventional phased - array radars form a single coherent transmit beam and measure the backscattered response... steering vector for a SI MO array with nr"/? receiver phase centers located at positions xm + y„. This is how the MIMO virtual array arises. The waveforms

  4. Fabry-Perot interferometer based Mie Doppler lidar for low tropospheric wind observation

    NASA Astrophysics Data System (ADS)

    Xia, Haiyun; Sun, Dongsong; Yang, Yuanhong; Shen, Fahua; Dong, Jingjing; Kobayashi, Takao

    2007-10-01

    Similar in principle to recent implementations of a lidar system at 355 nm [Opt. Lett. 25, 1231 (2000), Appl. Opt. 44, 6023 (2005)], an incoherent-detection Mie Doppler wind lidar at 1064 nm was developed and deployed in 2005 [Opt. Rev. 12, 409 (2005)] for wind measurements in the low troposphere, taking advantage of aerosol scattering for signal enhancement. We present a number of improvements made to the original 1064 nm system to increase its robustness for long-period operation. These include a multimode fiber for receiving the reference signal, a mode scrambler to allow uniform illumination over the Fabry-Perot interferometer, and a fast scannable Fabry-Perot interferometer for calibration and for the determination of outgoing laser frequency during the wind observation. With these improvements in stability, the standard deviation of peak transmission and FWHM of the Fabry-Perot interferometer was determined to be 0.49% and 0.36%, respectively. The lidar wind measurements were validated within a dynamic range of ±40 m/s. Comparison experiments with both wind profiler radar and Vaisala wiresonde show good agreement with expected observation error. An example of 24 h continuous observations of wind field and aerosol backscatter coefficients in the boundary layer with 1 min and 30 m temporal and spatial resolution and 3 m/s tolerated wind velocity error is presented and fully demonstrates the stability and robustness of this lidar.

  5. Spot size effects in miniaturized moving-optical-wedge interferometer.

    PubMed

    Al-Saeed, Tarek A; Khalil, Diaa A

    2011-06-10

    In this paper we study the effect of diffraction on the performance of a miniaturized moving-optical-wedge interferometer. By using the Gaussian model, we calculate the degradation of the interferometer visibility due to diffraction effects. We use this model to optimize the detector size required to obtain maximum visibility and study its effect on resolution of Fourier transform spectrometers based on a moving-optical-wedge interferometer. A comparison between these effects in Michelson and wedge interferometers is also presented showing the advantage of the moving-optical-wedge interferometer in suppressing the diffraction effects with respect to the Michelson interferometer.

  6. Interferometer for Testing in Vibration Environments

    NASA Technical Reports Server (NTRS)

    Eng, Ron; Freischlad, Klaus; Hadaway, James; Stahl, H. Philip (Technical Monitor)

    2002-01-01

    Temporal phase shifting interferometers require a stable environment during the data acquisition, so that well controlled phase steps can be introduced between successively acquired interferograms. In contrast, single-frame interferometers need to acquire only one interferogram to provide a phase map with very good precision at high spatial resolution. Thus these interferometers are well suited for the interferometric testing of large optics with long radius of curvature for which vibration isolation is difficult, eg. testing astronomical telescope mirrors in a test tower, or testing space optics inside a cryogenic vacuum chamber. This paper describes the Instantaneous Phase Interferometer (IPI) by ADE Phase Shift, together with measurement results at NASA. The IPI consists of a polarization Twyman-Green interferometer operating at 632.8 nm, with single-frame data acquisition based on a spatial carrier technique. The spatial carrier fringes are generated by introducing large amount of tilt between the test beam and the reference beam. The phase information of the optical surface under test is encoded in the straightness of the interference fringes, which can be detected in a single frame with spatial sampling of 1000 x 1000 pixels. Measurements taken at the NASA Marshall Space Flight Cater in support of the characterization of developmental optics for the Next Generation Space Telescope are presented. Such tests consist of a mirror placed inside a cryogenic vacuum chamber, with the IPI placed outside the test chamber without any additional vibration isolation.

  7. Michelson interferometer based spatial phase shift shearography.

    PubMed

    Xie, Xin; Yang, Lianxiang; Xu, Nan; Chen, Xu

    2013-06-10

    This paper presents a simple spatial phase shift shearography based on the Michelson interferometer. The Michelson interferometer based shearographic system has been widely utilized in industry as a practical nondestructive test tool. In the system, the Michelson interferometer is used as a shearing device to generate a shearing distance by tilting a small angle in one of the two mirrors. In fact, tilting the mirror in the Michelson interferometer also generates spatial frequency shift. Based on this feature, we introduce a simple Michelson interferometer based spatial phase shift shearography. The Fourier transform (FT) method is applied to separate the spectrum on the spatial frequency domain. The phase change due to the loading can be evaluated using a properly selected windowed inverse-FT. This system can generate a phase map of shearography by using only a single image. The effects of shearing angle, spatial resolution of couple charge device camera, and filter methods are discussed in detail. The theory and the experimental results are presented.

  8. Process control system using polarizing interferometer

    DOEpatents

    Schultz, Thomas J.; Kotidis, Petros A.; Woodroffe, Jaime A.; Rostler, Peter S.

    1994-01-01

    A system for non-destructively measuring an object and controlling industrial processes in response to the measurement is disclosed in which an impulse laser generates a plurality of sound waves over timed increments in an object. A polarizing interferometer is used to measure surface movement of the object caused by the sound waves and sensed by phase shifts in the signal beam. A photon multiplier senses the phase shift and develops an electrical signal. A signal conditioning arrangement modifies the electrical signals to generate an average signal correlated to the sound waves which in turn is correlated to a physical or metallurgical property of the object, such as temperature, which property may then be used to control the process. External, random vibrations of the workpiece are utilized to develop discernible signals which can be sensed in the interferometer by only one photon multiplier. In addition the interferometer includes an arrangement for optimizing its sensitivity so that movement attributed to various waves can be detected in opaque objects. The interferometer also includes a mechanism for sensing objects with rough surfaces which produce speckle light patterns. Finally the interferometer per se, with the addition of a second photon multiplier is capable of accurately recording beam length distance differences with only one reading.

  9. Furnace control apparatus using polarizing interferometer

    DOEpatents

    Schultz, T.J.; Kotidis, P.A.; Woodroffe, J.A.; Rostler, P.S.

    1995-03-28

    A system for nondestructively measuring an object and controlling industrial processes in response to the measurement is disclosed in which an impulse laser generates a plurality of sound waves over timed increments in an object. A polarizing interferometer is used to measure surface movement of the object caused by the sound waves and sensed by phase shifts in the signal beam. A photon multiplier senses the phase shift and develops an electrical signal. A signal conditioning arrangement modifies the electrical signals to generate an average signal correlated to the sound waves which in turn is correlated to a physical or metallurgical property of the object, such as temperature, which property may then be used to control the process. External, random vibrations of the workpiece are utilized to develop discernible signals which can be sensed in the interferometer by only one photon multiplier. In addition the interferometer includes an arrangement for optimizing its sensitivity so that movement attributed to various waves can be detected in opaque objects. The interferometer also includes a mechanism for sensing objects with rough surfaces which produce speckle light patterns. Finally the interferometer per se, with the addition of a second photon multiplier is capable of accurately recording beam length distance differences with only one reading. 38 figures.

  10. Furnace control apparatus using polarizing interferometer

    DOEpatents

    Schultz, Thomas J.; Kotidis, Petros A.; Woodroffe, Jaime A.; Rostler, Peter S.

    1995-01-01

    A system for non-destructively measuring an object and controlling industrial processes in response to the measurement is disclosed in which an impulse laser generates a plurality of sound waves over timed increments in an object. A polarizing interferometer is used to measure surface movement of the object caused by the sound waves and sensed by phase shifts in the signal beam. A photon multiplier senses the phase shift and develops an electrical signal. A signal conditioning arrangement modifies the electrical signals to generate an average signal correlated to the sound waves which in turn is correlated to a physical or metallurgical property of the object, such as temperature, which property may then be used to control the process. External, random vibrations of the workpiece are utilized to develop discernible signals which can be sensed in the interferometer by only one photon multiplier. In addition the interferometer includes an arrangement for optimizing its sensitivity so that movement attributed to various waves can be detected in opaque objects. The interferometer also includes a mechanism for sensing objects with rough surfaces which produce speckle light patterns. Finally the interferometer per se, with the addition of a second photon multiplier is capable of accurately recording beam length distance differences with only one reading.

  11. Process control system using polarizing interferometer

    DOEpatents

    Schultz, T.J.; Kotidis, P.A.; Woodroffe, J.A.; Rostler, P.S.

    1994-02-15

    A system for nondestructively measuring an object and controlling industrial processes in response to the measurement is disclosed in which an impulse laser generates a plurality of sound waves over timed increments in an object. A polarizing interferometer is used to measure surface movement of the object caused by the sound waves and sensed by phase shifts in the signal beam. A photon multiplier senses the phase shift and develops an electrical signal. A signal conditioning arrangement modifies the electrical signals to generate an average signal correlated to the sound waves which in turn is correlated to a physical or metallurgical property of the object, such as temperature, which property may then be used to control the process. External, random vibrations of the workpiece are utilized to develop discernible signals which can be sensed in the interferometer by only one photon multiplier. In addition the interferometer includes an arrangement for optimizing its sensitivity so that movement attributed to various waves can be detected in opaque objects. The interferometer also includes a mechanism for sensing objects with rough surfaces which produce speckle light patterns. Finally the interferometer per se, with the addition of a second photon multiplier is capable of accurately recording beam length distance differences with only one reading. 38 figures.

  12. Circular common-path point diffraction interferometer.

    PubMed

    Du, Yongzhao; Feng, Guoying; Li, Hongru; Vargas, J; Zhou, Shouhuan

    2012-10-01

    A simple and compact point-diffraction interferometer with circular common-path geometry configuration is developed. The interferometer is constructed by a beam-splitter, two reflection mirrors, and a telescope system composed by two lenses. The signal and reference waves travel along the same path. Furthermore, an opaque mask containing a reference pinhole and a test object holder or test window is positioned in the common focal plane of the telescope system. The object wave is divided into two beams that take opposite paths along the interferometer. The reference wave is filtered by the reference pinhole, while the signal wave is transmitted through the object holder. The reference and signal waves are combined again in the beam-splitter and their interference is imaged in the CCD. The new design is compact, vibration insensitive, and suitable for the measurement of moving objects or dynamic processes.

  13. Wide Angle Michelson Doppler Imaging Interferometer (WAMDII)

    NASA Technical Reports Server (NTRS)

    Roberts, W. T.

    1985-01-01

    The wide angle Michelson Doppler imaging interferometer (WAMDII) is a specialized type of optical Michelson interferometer working at sufficiently long path difference to measure Doppler shifts and to infer Doppler line widths of naturally occurring upper atmospheric Gaussian line emissions. The instrument is intended to measure vertical profiles of atmospheric winds and temperatures within the altitude range of 85 km to 300 km. The WAMDII consists of a Michelson interferometer followed by a camera lens and an 85 x 106 charge coupled device photodiode array. Narrow band filters in a filter wheel are used to isolate individual line emissions and the lens forms an image of the emitting region on the charge coupled device array.

  14. Wide Angle Michelson Doppler Imaging Interferometer (WAMDII)

    NASA Technical Reports Server (NTRS)

    Roberts, B.

    1986-01-01

    The wide angle Michelson Doppler imaging interferometer (WAMDII) is a specialized type of optical Michelson interferometer working at sufficiently long path difference to measure Doppler shifts and to infer Doppler line widths of naturally occurring upper atmospheric Gaussian line emissions. The instrument is intended to measure vertical profiles of atmospheric winds and temperatures within the altitude range of 85 km to 300 km. The WAMDII consists of a Michelson interferometer followed by a camera lens and an 85 x 106 charge coupled device photodiode array. Narrow band filters in a filter wheel are used to isolate individual line emissions and the lens forms an image of the emitting region on the charge coupled device array.

  15. A heterodyne interferometer for angle metrology.

    PubMed

    Hahn, Inseob; Weilert, M; Wang, X; Goullioud, R

    2010-04-01

    We have developed a compact, high-resolution, angle measurement instrument based on a heterodyne interferometer. Common-path heterodyne interferometer metrology is used to measure displacements of a reflective target surface. In the interferometer set up, an optical mask is used to sample the laser beam reflecting back from four areas on a target surface. From the relative displacement measurements of the target surface areas, we can simultaneously determine angular rotations around two orthogonal axes in a plane perpendicular to the measurement beam propagation direction. The device is used in a testbed for a tracking telescope system where pitch and yaw angle measurements of a flat mirror are performed. Angle noise measurement of the device shows 0.1 nrad/square root of Hz at 1 Hz, at a working distance of 1 m. The operation range and nonlinearity of the device when used with a flat mirror is approximately +/-0.15 mrad, and 3 microrad rms, respectively.

  16. Fourier Transform Fabry-Perot Interferometer

    NASA Technical Reports Server (NTRS)

    Snell, Hilary E.; Hays, Paul B.

    1992-01-01

    We are developing a compact, rugged, high-resolution remote sensing instrument with wide spectral scanning capabilities. This relatively new type of instrument, which we have chosen to call the Fourier-Transform Fabry-Perot Interferometer (FT-FPI), is accomplished by mechanically scanning the etalon plates of a Fabry-Perot interferometer (FPI) through a large optical distance while examining the concomitant signal with a Fourier-transform analysis technique similar to that employed by the Michelson interferometer. The FT-FPI will be used initially as a ground-based instrument to study near-infrared atmospheric absorption lines of trace gases using the techniques of solar absorption spectroscopy. Future plans include modifications to allow for measurements of trace gases in the stratosphere using spectral lines at terahertz frequencies.

  17. A heterodyne interferometer for angle metrology

    SciTech Connect

    Hahn, Inseob; Weilert, M.; Wang, X.; Goullioud, R.

    2010-04-15

    We have developed a compact, high-resolution, angle measurement instrument based on a heterodyne interferometer. Common-path heterodyne interferometer metrology is used to measure displacements of a reflective target surface. In the interferometer set up, an optical mask is used to sample the laser beam reflecting back from four areas on a target surface. From the relative displacement measurements of the target surface areas, we can simultaneously determine angular rotations around two orthogonal axes in a plane perpendicular to the measurement beam propagation direction. The device is used in a testbed for a tracking telescope system where pitch and yaw angle measurements of a flat mirror are performed. Angle noise measurement of the device shows 0.1 nrad/{radical}(Hz) at 1 Hz, at a working distance of 1 m. The operation range and nonlinearity of the device when used with a flat mirror is approximately {+-}0.15 mrad, and 3 {mu}rad rms, respectively.

  18. Coherence and information in a fiber interferometer

    NASA Astrophysics Data System (ADS)

    Kellerer, Aglaé; Wright, Sidney; Lacour, Sylvestre

    2017-01-01

    We present an experiment based on a fibered Mach-Zehnder interferometer, with the aim of familiarizing students with fibered optics and interferometry, and of improving their understanding of optical amplification. The laboratory project has two parts. In the first, students modulate the optical path of the interferometer to study the spectra of light sources via Fourier Transform Spectroscopy. In the second, an optical amplifier is placed in one or both arms of the interferometer. The set-up uses monomode, polarization-maintaining fibers that propagate light with a wavelength of 1.5 μm. Here, we describe the set-up and the analysis of the measurements, and we present results from student reports.

  19. The Table Mountain 8-mm wavelength interferometer

    NASA Technical Reports Server (NTRS)

    Janssen, M. A.; Gary, B. L.; Gulkis, S.; Olsen, E. T.; Soltis, F. S.; Yamane, N. I.

    1979-01-01

    A two-element radio interferometer operating at 8.33-mm wavelength has been developed at the Jet Propulsion Laboratory's Table Mountain Observatory near Wrightwood, CA. The interferometer employs a 5.5-m and a 3-m diameter antenna on an east-west baseline of 60 or 120 m, yielding fringe spacings at transit of 28 or 14 arcsec, respectively. The broad intermediate-frequency bandpass of 100-350 MHz and the system noise temperature of 500 K provide high sensitivity for the measurement of continuum sources. The interferometer has been used for high-resolution studies of the planets and the sun, and it is currently being adapted to study solar flare emissions at high spatial and time resolution.

  20. 66. VIEW SHOWING HOLD FOR RADAR CABLES AT RADAR SITE, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    66. VIEW SHOWING HOLD FOR RADAR CABLES AT RADAR SITE, LOOKING NORTH Everett Weinreb, photographer, March 1988 - Mount Gleason Nike Missile Site, Angeles National Forest, South of Soledad Canyon, Sylmar, Los Angeles County, CA

  1. Design of the ST 3 Formation Flying Interferometer

    NASA Technical Reports Server (NTRS)

    Lay, O.; Blackwood, G.; Dubovitsky, S.; Gorham, P.; Linfield, R.

    1999-01-01

    The interferometer will operate in both a single spacecraft mode and a formation flying mode using two spacecraft. The primary goal is to validate interferometer and formation flying technology for future missions.

  2. Optimum quantum states for interferometers with fixed and moving mirrors

    SciTech Connect

    Luis, Alfredo

    2004-04-01

    We address a systematic approach to the study of the optimum states reaching maximum resolution for interferometers with moving mirrors. We find a correspondence between the optimum states for interferometers with fixed and moving mirrors.

  3. (presentation) Precision Mechanisms for Space Interferometers: A Tutorial

    NASA Technical Reports Server (NTRS)

    Agronin, Michael L.

    1993-01-01

    To maximize salability, spaceborne interferometer designs must minimize actuator cost while maximizing science quality and quantity. Interferometer designers must have the knowledge to design a system with the simplist, most reliable, and least expensive actuators possible.

  4. Geometrical misalignment retrieval of the IASI interferometer

    NASA Astrophysics Data System (ADS)

    Henault, Francois; Hebert, Philippe-Jean; Lucchini, Christophe; Miras, Didier

    1999-12-01

    The IASI instrument (Infrared Atmospheric Sounding Interferometer) is a Fourier-Transform Spectrometer (FTS) providing spectra of the Earth's atmosphere observed from space. The heart of the instrument is a Michelson interferometer (IHOS) equipped with two hollow cube-corners retro-reflectors in place of the classical flat mirrors. The main alignment requirements of the IASI interferometer are the lateral shift, or shear, of the moving cube-corner (seen through the beamsplitter) and the misalignment of its scanning axis: these contributions should not exceed 20 micrometer and 250 (mu) rad respectively during the five years mission in orbit. Thus the most difficult challenge of the IHOS integration on-ground probably is their measurement accuracy, which shall respectively be better than 1 micrometer and 100 (mu) rad. The envisaged characterization method consists in a specific data processing of the fringe patterns created by the interferometer at four different points located in the IHOS Field of View (FoV), corresponding to the IASI instrument pixels. For each acquired interferogram the Optical Path Difference (OPD) created by the interferometer are evaluated using a double Fourier-transform algorithm, and the results are combined together in order to retrieve the apparent trajectory of the mobile cube-corner. This principle was tested on a breadboard interferometer already assembled in the CNES laboratories. The numerical results presented herein tend to demonstrate the efficiency of the method, since the achieved accuracy does not exceed 1.2 micrometer (whatever the cube-corner axial position) and 120 (mu) rad respectively. The main error sources also are discussed.

  5. Radar Imaging of Mercury

    NASA Astrophysics Data System (ADS)

    Harmon, John K.

    2007-10-01

    Earth-based radar has been one of the few, and one of the most important, sources of new information about Mercury during the three decades since the Mariner 10 encounters. The emphasis during the past 15 years has been on full-disk, dual-polarization imaging of the planet, an effort that has been facilitated by the development of novel radar techniques and by improvements in radar systems. Probably the most important result of the imaging work has been the discovery and mapping of radar-bright features at the poles. The radar scattering properties of these features, and their confinement to permanently shaded crater floors, is consistent with volume backscatter from a low-loss volatile such as clean water ice. Questions remain, however, regarding the source and long-term stability of the putative ice, which underscores the need for independent confirmation by other observational methods. Radar images of the non-polar regions have also revealed a plethora of bright features, most of which are associated with fresh craters and their ejecta. Several very large impact features, with rays and other bright ejecta spreading over distances of 1,000 km or more, have been traced to source craters with diameters of 80-125 km. Among these large rayed features are some whose relative faintness suggests that they are being observed in an intermediate stage of degradation. Less extended ray/ejecta features have been found for some of the freshest medium-size craters such as Kuiper and Degas. Much more common are smaller (<40 km diameter) fresh craters showing bright rim-rings but little or no ray structure. These smaller radar-bright craters are particularly common over the H-7 quadrangle. Diffuse areas of enhanced depolarized brightness have been found in the smooth plains, including the circum-Caloris planitiae and Tolstoj Basin. This is an interesting finding, as it is the reverse of the albedo contrast seen between the radar-dark maria and the radar-bright cratered highlands

  6. Radar Imaging of Mercury

    NASA Astrophysics Data System (ADS)

    Harmon, John K.

    Earth-based radar has been one of the few, and one of the most important, sources of new information about Mercury during the three decades since the Mariner 10 encounters. The emphasis during the past 15 years has been on full-disk, dual-polarization imaging of the planet, an effort that has been facilitated by the development of novel radar techniques and by improvements in radar systems. Probably the most important result of the imaging work has been the discovery and mapping of radar-bright features at the poles. The radar scattering properties of these features, and their confinement to permanently shaded crater floors, is consistent with volume backscatter from a low-loss volatile such as clean water ice. Questions remain, however, regarding the source and long-term stability of the putative ice, which underscores the need for independent confirmation by other observational methods. Radar images of the non-polar regions have also revealed a plethora of bright features, most of which are associated with fresh craters and their ejecta. Several very large impact features, with rays and other bright ejecta spreading over distances of 1,000 km or more, have been traced to source craters with diameters of 80-125 km. Among these large rayed features are some whose relative faintness suggests that they are being observed in an intermediate stage of degradation. Less extended ray/ejecta features have been found for some of the freshest medium-size craters such as Kuiper and Degas. Much more common are smaller (<40 km diameter) fresh craters showing bright rim-rings but little or no ray structure. These smaller radar-bright craters are particularly common over the H-7 quadrangle. Diffuse areas of enhanced depolarized brightness have been found in the smooth plains, including the circum-Caloris planitiae and Tolstoj Basin. This is an interesting finding, as it is the reverse of the albedo contrast seen between the radar-dark maria and the radar-bright cratered highlands

  7. Reflective grating interferometer: a folded reversal and shearing wave-front interferometer.

    PubMed

    Ferraro, Pietro; De, Nicola Sergio; Finizio, Andrea; Pierattini, Giovanni

    2002-01-10

    The reflecting grating interferometer (RGI) is a folded and reversal wave-front interferometer sensitive only to asymmetrical aberrations such as third-order coma. The RGI can isolate and evaluate coma both in nearly collimated and in noncollimated beams. We propose a RGI with a different optical configuration that includes a lateral shearing in addition to folding and reversal operations. With lateral shear, the RGI also becomes sensitive to other terms of third-order aberrations such as defocusing, astigmatism, and spherical aberration. Optical path difference equations for interpreting interferograms and numerical simulations are presented to show how the interferometer works in the shearing configuration. Its potential applications are described and discussed.

  8. Nulling Measurements with the Keck Interferometer

    SciTech Connect

    Serabyn, Eugene

    2009-08-05

    The Keck Interferometer provides a mid-infrared nulling capability that is designed to detect faint mid-infrared emission from the immediate vicinity of bright stars. The Keck Interferometer Nuller (KIN) has now been used to carry out initial shared-risk science observations, followed by three nulling key-science projects performed in the 2008 observing semesters. This paper describes the novel measurement technique employed by the KIN, and lists some of the initial observations obtained with it. These data sets are now in the process of being analyzed, and results should begin emerging in the near future.

  9. Observing NGC 4151 with the Keck Interferometer

    NASA Technical Reports Server (NTRS)

    Swain, Mark R.

    2004-01-01

    Observations of the nucleus of NGC 4151 at 2.2 microns using the two 10-meter Keck telescopes as an interferometer show a marginally resolved source less than or equal to 0.1 pc in diameter. These observations are the first measurement of an extragalactic source with an optical/IR interferometer. These observations represent a ten-fold improvement in angular resolution when compared to previous near-infrared measurements of AGN and make it possible to test the subparsecscale, near-infrared emission models of NGC 4151.

  10. Self-referenced interferometer for cylindrical surfaces.

    PubMed

    Šarbort, Martin; Řeřucha, Šimon; Holá, Miroslava; Buchta, Zdeněk; Lazar, Josef

    2015-11-20

    We present a new interferometric method for shape measurement of hollow cylindrical tubes. We propose a simple and robust self-referenced interferometer where the reference and object waves are represented by the central and peripheral parts, respectively, of the conical wave generated by a single axicon lens. The interferogram detected by a digital camera is characterized by a closed-fringe pattern with a circular carrier. The interference phase is demodulated using spatial synchronous detection. The capabilities of the interferometer are experimentally tested for various hollow cylindrical tubes with lengths up to 600 mm.

  11. Nulling Measurements with the Keck Interferometer

    NASA Astrophysics Data System (ADS)

    Serabyn, Eugene

    2009-08-01

    The Keck Interferometer provides a mid-infrared nulling capability that is designed to detect faint mid-infrared emission from the immediate vicinity of bright stars. The Keck Interferometer Nuller (KIN) has now been used to carry out initial shared-risk science observations, followed by three nulling key-science projects performed in the 2008 observing semesters. This paper describes the novel measurement technique employed by the KIN, and lists some of the initial observations obtained with it. These data sets are now in the process of being analyzed, and results should begin emerging in the near future.

  12. Characterization of the wind imaging interferometer.

    PubMed

    Hersom, C H; Shepherd, G G

    1995-06-01

    The Wind Imaging Interferometer is a field-widened Michelson interferometer onboard the Upper Atmosphere Research Satellite. The characterization of the instrument required a pixel-by-pixel evaluation of the instrument performance. Some of the configurations, techniques, and results of the characterization are summarized. Throughput was excellent and equivalent to a total system quantum efficiency of ~10%. Localized spatial noise in response has been attributed to scattering from residual surface effects on the CCD. Instrument visibility factors greater than 90% were measured with distinct distribution patterns over the field of view that were different for the night and day apertures. The instrument phase for zero wind was determined with laboratory airglow sources.

  13. Multiple reflection Michelson interferometer with picometer resolution.

    PubMed

    Pisani, Marco

    2008-12-22

    A Michelson interferometer based on an optical set-up allowing multiple reflection between two plane mirrors performs the multiplication of the optical path by a factor N, proportionally increasing the resolution of the measurement. A multiplication factor of almost two orders of magnitude has been demonstrated with a simple set-up. The technique can be applied to any interferometric measurement where the classical interferometer limits due to fringe nonlinearities and quantum noise are an issue. Applications in precision engineering, vibration analysis, nanometrology, and spectroscopy are foreseen.

  14. Digital holographic Michelson interferometer for nanometrology

    NASA Astrophysics Data System (ADS)

    Sevrygin, Alexander A.; Korotkov, V. I.; Pulkin, S. A.; Tursunov, I. M.; Venediktov, D. V.; Venediktov, V. Yu.; Volkov, O. V.

    2014-11-01

    The paper considers the dynamic holographic interferometry schemes with amplification (multiplication) of holographic fringes and with correction for distortions, imposed by the interferometer scheme elements. The use of digital microscope and of the matrix light modulator with direct addressing provides the completely digital closed-loop performance of the overall system for real-time evaluation of nano-scale objects size. Considered schemes were verified in the laboratory experiment, using the Michelson micro-interferometer, equipped by the USB-microscope and digital holography stage, equipped by the Holoeye spatial light modulator.

  15. Bayesian estimation of differential interferometer phase

    SciTech Connect

    Stockton, John K.; Wu Xinan; Kasevich, Mark A.

    2007-09-15

    We apply Bayesian logic to optimally estimate the differential phase in a discrete-time, dual-interferometer measurement. This method is particularly relevant to the case of a gravity gradiometer, where the gravity gradient between cold-atom fountain interferometers can be estimated from the differential phase, despite the presence of large common phase (acceleration) fluctuations. Given an accurate model, the bias-free algorithm we present is optimal and leverages experimental knowledge of the system noise, classical or quantum, to outperform other typical estimators, including ellipse-fitting techniques.

  16. SCSI: the Southern Connecticut Stellar Interferometer

    NASA Astrophysics Data System (ADS)

    Horch, Elliott P.; Weiss, Samuel A.; Rupert, Justin D.; DiMaio, Alex J.; Nusdeo, Daniel A.; Peronio, Pietro; Rech, Ivan; Gulinatti, Angelo; Giudice, Andrea

    2016-08-01

    The construction of a new prototype visible-light intensity interferometer for use in stellar astronomy is described. The instrument is located in New Haven, Connecticut, at Southern Connecticut State University, but key components of the system are also portable and have been taken to existing research-class telescopes to maximize sensitivity and baseline. The interferometer is currently a two-station instrument, but it is easily expandable to several stations for simultaneous measurement using multiple baselines. The design features single photon avalanche diode (SPAD) arrays, which increase the throughput and signal-to-noise ratio of the instrument. Predicted system performance and preliminary observations will be discussed.

  17. A frequency selective atom interferometer magnetometer

    NASA Astrophysics Data System (ADS)

    Braje, D. A.; DeSavage, S. A.; Adler, C. L.; Davis, J. P.; Narducci, F. A.

    2014-01-01

    In this article, we discuss the magnetic-field frequency selectivity of a time-domain interferometer based on the number and timing of intermediate ? pulses. We theoretically show that by adjusting the number of ? pulses and the ?-pulse timing, we can control the frequency selectivity of the interferometer to time varying and DC magnetic fields. We present experimental data demonstrating increased coherence time due to bandwidth filtering with the inclusion of a ? pulse between the initial and final ? pulses, which mitigates sensitivity to low frequency magnetic fields.

  18. A barrier radar concept

    NASA Astrophysics Data System (ADS)

    Marshall, J.; Ball, C.; Weissman, I.

    A description is given of a low power, light-weight radar that can be quickly set up and operated on batteries for extended periods of time to detect airborne intruders. With low equipment and operating costs, it becomes practical to employ a multiplicity of such radars to provide an unbroken intrusion fence over the desired perimeter. Each radar establishes a single transmitted fan beam extending vertically from horizon to horizon. The beam is generated by a two-face array antenna built in an A-frame configuration and is shaped, through phasing of the array elements, to concentrate the transmitter power in a manner consistent with the expected operating altitude ceiling of the targets of interest. The angular width of this beam in the dimension transverse to the fan depends on the radar transmission frequency and the antenna aperture dimension, but is typically wide enough so that a target at the maximum altitude or range will require tens of seconds to pass through the beam. A large number of independent samples of radar data will thus be available to provide many opportunities for target detection.

  19. 33. Perimeter acquisition radar building room #320, perimeter acquisition radar ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    33. Perimeter acquisition radar building room #320, perimeter acquisition radar operations center (PAROC), contains the tactical command and control group equipment required to control the par site. Showing spacetrack monitor console - Stanley R. Mickelsen Safeguard Complex, Perimeter Acquisition Radar Building, Limited Access Area, between Limited Access Patrol Road & Service Road A, Nekoma, Cavalier County, ND

  20. Coordinated Radar Resource Management for Networked Phased Array Radars

    DTIC Science & Technology

    2014-12-01

    Research and Development Canada Ottawa, Canada K1A 0Z4 Email: Peter.Moo@drdc-rddc.gc.ca Abstract A phased array radar has the ability to rapidly and...search and Development Canada (DRDC) Ottawa to analyse the performance of radar resource management techniques for naval radars operating in a littoral

  1. Phase modulating the Urbana radar

    NASA Technical Reports Server (NTRS)

    Herrington, L. J., Jr.; Bowhill, S. A.

    1983-01-01

    The design and operation of a switched phase modulation system for the Urbana Radar System are discussed. The system is implemented and demonstrated using a simple procedure. The radar system and circuits are described and analyzed.

  2. A comparison of Northern Hemisphere winds using SuperDARN meteor trail and MF radar wind measurements

    NASA Astrophysics Data System (ADS)

    Hussey, G. C.; Meek, C. E.; André, D.; Manson, A. H.; Sofko, G. J.; Hall, C. M.

    The main purpose of the Super Dual Auroral Radar Network (SuperDARN) is to use paired radars to deduce the F-region convection from Doppler measurements of backscatter seen at large ranges, typically beyond ~900 km. Nearer to each HF radar, the nearest ranges at ~165-400 km are dominated by meteor trail echoes. Once formed, the motion of these meteor trails is normally controlled by neutral winds in the 80-110 km altitude range. By combining the line-of-sight velocities from all 16 receiver beams (~52° in azimuth) of a given SuperDARN radar, it is possible to determine the full horizontal wind vector field over the meteor trail height range. Elevation angles are also measured using an interferometer mode and as such height information can, in principle, be obtained from the combined range and elevation angle data. A comparison with neutral wind measurements from a colocated (Saskatoon, Canada) MF wind radar indicates good agreement between the two radar systems at heights of ~95 km. Based on these detailed comparisons, a simple common method for determining two-dimensional winds for all SuperDARN radars, which have extensive longitudinal coverage, was developed. Comparisons with other systems used for dynamical studies of tides and planetary waves are desirable and prove to be essential to obtain a good SuperDARN neutral wind motion analysis. The MF radars at Saskatoon and Troms[do], Norway, are located near the western and eastern ends of the Northern Hemisphere network of six SuperDARN radars. Comparisons between the two types of radars for two seasonal intervals (September and December) show that the SuperDARN radars provide good longitudinal coverage of tides in support of the more detailed MF radar data. The two systems complement each other effectively.

  3. Phase conjugate Twyman-Green interferometer for testing conicoidal surfaces

    NASA Technical Reports Server (NTRS)

    Shukla, R. P.; Dokhanian, Mostafa; Venkateswarlu, Putcha; George, M. C.

    1990-01-01

    An application of a phase conjugate Twyman-Green interferometer for testing a parabolic mirror is demonstrated. The interferometer is free from aberrations due to the self-focusing property of the phase conjugate mirror in one arm of the interferometer. It does not require a precision spherical mirror in the reference arm.

  4. A new interferometer capable of measuring small optical path differences.

    PubMed

    Kinzly, R E

    1967-01-01

    This paper reports the development of a new type of interferometer capable of measuring optical path differences of lambda/1000 or less. Experiments that verify this capability were performed and are reported. The interferometer exhibits, in addition to a high sensitivity, an advantage of increased environmental stability over more conventional interferometers which depend upon optical path changes manifested as fringe shifts.

  5. An electron Talbot-Lau interferometer and magnetic field sensing

    SciTech Connect

    Bach, Roger; Batelaan, Herman; Gronniger, Glen

    2013-12-16

    We present a demonstration of a three grating Talbot-Lau interferometer for electrons. As a proof of principle, the interferometer is used to measure magnetic fields. The device is similar to the classical Moiré deflectometer. The possibility to extend this work to build a scaled-up electron deflectometer or interferometer for sensitive magnetic field sensing is discussed.

  6. Coherent IR radar technology

    NASA Astrophysics Data System (ADS)

    Gschwendtner, A. B.; Harney, R. C.; Hull, R. J.

    Recent progress in the development of coherent IR radar equipment is reviewed, focusing on the Firepond laser radar installation and the more compact systems derived for it. The design and capabilities of Firepond as a long-range satellite-tracking device are outlined. The technological improvements necessary to make laser radar mobile are discussed: a lightweight, stable 5-10-W transmitter laser for both CW and pulsed operation, a 12-element HgCdTe detector array, an eccentric-pupil Ritchey-Chretien telescope, and a combination of near-field phase modification and anamorphic expansion to produce a fan beam of relatively uniform intensity. Sample images obtained with a prototype system are shown, and the applicability of the mobile system to range-resolved coherent DIAL measurement is found to be similar to that of a baseline DIAL system.

  7. The MST Radar Technique

    NASA Technical Reports Server (NTRS)

    Balsley, B. B.

    1985-01-01

    The past ten year have witnessed the development of a new radar technique to examine the structure and dynamics of the atmosphere between roughly 1 to 100 km on a continuous basis. The technique is known as the MST (for Mesosphere-Stratosphere-Troposphere) technique and is usable in all weather conditions, being unaffected by precipitation or cloud cover. MST radars make use of scattering from small scale structure in the atmospheric refractive index, with scales of the order of one-half the radar wavelength. Pertinent scale sizes for middle atmospheric studies typically range between a fraction of a meter and a few meters. The structure itself arises primarily from atmospheric turbulence. The technique is briefly described along with the meteorological parameters it measures.

  8. Radar data smoothing filter study

    NASA Technical Reports Server (NTRS)

    White, J. V.

    1984-01-01

    The accuracy of the current Wallops Flight Facility (WFF) data smoothing techniques for a variety of radars and payloads is examined. Alternative data reduction techniques are given and recommendations are made for improving radar data processing at WFF. A data adaptive algorithm, based on Kalman filtering and smoothing techniques, is also developed for estimating payload trajectories above the atmosphere from noisy time varying radar data. This algorithm is tested and verified using radar tracking data from WFF.

  9. Systems and Methods for Radar Data Communication

    NASA Technical Reports Server (NTRS)

    Bunch, Brian (Inventor); Szeto, Roland (Inventor); Miller, Brad (Inventor)

    2013-01-01

    A radar information processing system is operable to process high bandwidth radar information received from a radar system into low bandwidth radar information that may be communicated to a low bandwidth connection coupled to an electronic flight bag (EFB). An exemplary embodiment receives radar information from a radar system, the radar information communicated from the radar system at a first bandwidth; processes the received radar information into processed radar information, the processed radar information configured for communication over a connection operable at a second bandwidth, the second bandwidth lower than the first bandwidth; and communicates the radar information from a radar system, the radar information communicated from the radar system at a first bandwidth.

  10. Spaceborne Imaging Radar Symposium

    NASA Technical Reports Server (NTRS)

    Elachi, C.

    1983-01-01

    An overview of the present state of the art in the different scientific and technological fields related to spaceborne imaging radars was presented. The data acquired with the SEASAT SAR (1978) and Shuttle Imaging Radar, SIR-A (1981) clearly demonstrated the important emphasis in the 80's is going to be on in-depth research investigations conducted with the more flexible and sophisticated SIR series instruments and on long term monitoring of geophysical phenomena conducted from free-flying platforms such as ERS-1 and RADARSAT.

  11. Microwave radar oceanographic investigations

    NASA Technical Reports Server (NTRS)

    Jackson, F. C.

    1988-01-01

    The Radar Ocean Wave Spectrometer (ROWS) technique was developed and demonstrated for measuring ocean wave directional spectra from air and space platforms. The measurement technique was well demonstrated with data collected in a number of flight experiments involving wave spectral comparisons with wave buoys and the Surface Contour Radar (SCR). Recent missions include the SIR-B underflight experiment (1984), FASINEX (1986), and LEWEX (1987). ROWS related activity is presently concentrating on using the aircraft instrument for wave-processes investigations and obtaining the necessary support (consensus) for a satellite instrument development program. Prospective platforms include EOS and the Canadian RADARSAT.

  12. Spaceborne laser radar.

    NASA Technical Reports Server (NTRS)

    Flom, T.

    1972-01-01

    Development of laser systems to acquire and track targets in applications such as the rendezvous and docking of two spacecraft. A scan technique is described whereby a narrow laser beam is simultaneously scanned with an equally narrow receiver field-of-view without the aid of mechanical gimbals. Equations are developed in order to examine the maximum acquisition and tracking rates, and the maximum target range for a scanning laser radar system. A recently built prototype of a small, lightweight, low-power-consuming scanning laser radar is described.

  13. Radar Investigations of Asteroids

    NASA Technical Reports Server (NTRS)

    Ostro, S. J.

    1984-01-01

    Radar investigations of asteroids, including observations during 1984 to 1985 of at least 8 potential targets and continued analyses of radar data obtained during 1980 to 1984 for 30 other asteroids is proposed. The primary scientific objectives include estimation of echo strength, polarization, spectral shape, spectral bandwidth, and Doppler shift. These measurements yield estimates of target size, shape, and spin vector; place constraints on topography, morphology, density, and composition of the planetary surface; yield refined estimates of target orbital parameters; and reveals the presence of asteroidal satellites.

  14. SEASAT Synthetic Aperture Radar Data

    NASA Technical Reports Server (NTRS)

    Henderson, F. M.

    1981-01-01

    The potential of radar imagery from space altitudes is discussed and the advantages of radar over passive sensor systems are outlined. Specific reference is made to the SEASAT synthetic aperture radar. Possible applications include oil spill monitoring, snow and ice reconnaissance, mineral exploration, and monitoring phenomena in the urban environment.

  15. Side looking radar calibration study

    NASA Technical Reports Server (NTRS)

    Edwards, W. D.

    1975-01-01

    Calibration of an airborne sidelooking radar is accomplished by the use of a model that relates the radar parameters to the physical mapping situation. Topics discussed include: characteristics of the transmitters; the antennas; target absorption and reradiation; the receiver and map making or radar data processing; and the calibration process.

  16. Optical fiber voltage sensor based on Michelsion interferometer using Fabry-Perot demodulation interferometer

    NASA Astrophysics Data System (ADS)

    Chen, Xinwei; He, Shengnan; Li, Dandan; Wang, Kai; Fan, Yan'en; Wu, Shuai

    2014-11-01

    We present an optical fiber voltage sensor by Michelsion interferometer (MI) employing a Fabry-Perot (F-P) interferometer and the DC phase tracking (DCPT) signal processing method. By mounting a MI fabricated by an optical fiber coupler on a piezoelectric (PZT) transducer bar, a dynamic strain would be generated to change the optical path difference (OPD) of the interferometer when the measured voltage was applied on the PZT. Applying an F-P interferometer to demodulate the optical intensity variation output of the MI, the voltage can be obtained. The experiment results show that the relationship between the optical intensity variation and the voltage applied on the PZT is approximately linear. Furthermore, the phase generate carrier (PGC) algorithm was applied to demodulate the output of the sensor also.

  17. Control of Formation-Flying Multi-Element Space Interferometers with Direct Interferometer-Output Feedback

    NASA Technical Reports Server (NTRS)

    Lu, Hui-Ling; Cheng, Victor H. L.; Lyon, Richard G.; Carpenter, Kenneth G.

    2007-01-01

    The long-baseline space interferometer concept involving formation flying of multiple spacecrafts holds great promise as future space missions for high-resolution imagery. A major challenge of obtaining high-quality interferometric synthesized images from long-baseline space interferometers is to accurately control these spacecraft and their optics payloads in the specified configuration. Our research focuses on the determination of the optical errors to achieve fine control of long-baseline space interferometers without resorting to additional sensing equipment. We present a suite of estimation tools that can effectively extract from the raw interferometric image relative x/y, piston translational and tip/tilt deviations at the exit pupil aperture. The use of these error estimates in achieving control of the interferometer elements is demonstrated using simulated as well as laboratory-collected interferometric stellar images.

  18. Control of Formation-Flying Multi-Element Space Interferometers with Direct Interferometer-Output Feedback

    NASA Technical Reports Server (NTRS)

    Lu, Hui-Ling; Cheng, H. L.; Lyon, Richard G.; Carpenter, Kenneth G.

    2007-01-01

    The long-baseline space interferometer concept involving formation flying of multiple spacecraft holds great promise as future space missions for high-resolution imagery. A major challenge of obtaining high-quality interferometric synthesized images from long-baseline space interferometers is to accurately control these spacecraft and their optics payloads in the specified configuration. Our research focuses on the determination of the optical errors to achieve fine control of long-baseline space interferometers without resorting to additional sensing equipment. We present a suite of estimation tools that can effectively extract from the raw interferometric image relative x/y, piston translational and tip/tilt deviations at the exit pupil aperture. The use of these error estimates in achieving control of the interferometer elements is demonstrated using simulated as well as laboratory-collected interferometric stellar images.

  19. A Microwave Interferometer on an Air Track.

    ERIC Educational Resources Information Center

    Polley, J. Patrick

    1993-01-01

    Uses an air track and microwave transmitters and receivers to make a Michelson interferometer. Includes three experiments: (1) measuring the wavelength of microwaves, (2) measuring the wavelength of microwaves by using the Doppler Effect, and (3) measuring the Doppler shift. (MVL)

  20. Nonlinear atom interferometer surpasses classical precision limit.

    PubMed

    Gross, C; Zibold, T; Nicklas, E; Estève, J; Oberthaler, M K

    2010-04-22

    Interference is fundamental to wave dynamics and quantum mechanics. The quantum wave properties of particles are exploited in metrology using atom interferometers, allowing for high-precision inertia measurements. Furthermore, the state-of-the-art time standard is based on an interferometric technique known as Ramsey spectroscopy. However, the precision of an interferometer is limited by classical statistics owing to the finite number of atoms used to deduce the quantity of interest. Here we show experimentally that the classical precision limit can be surpassed using nonlinear atom interferometry with a Bose-Einstein condensate. Controlled interactions between the atoms lead to non-classical entangled states within the interferometer; this represents an alternative approach to the use of non-classical input states. Extending quantum interferometry to the regime of large atom number, we find that phase sensitivity is enhanced by 15 per cent relative to that in an ideal classical measurement. Our nonlinear atomic beam splitter follows the 'one-axis-twisting' scheme and implements interaction control using a narrow Feshbach resonance. We perform noise tomography of the quantum state within the interferometer and detect coherent spin squeezing with a squeezing factor of -8.2 dB (refs 11-15). The results provide information on the many-particle quantum state, and imply the entanglement of 170 atoms.

  1. Plasmonic interferometers: From physics to biosensing applications

    NASA Astrophysics Data System (ADS)

    Zeng, Xie

    Optical interferometry has a long history and wide range of applications. In recent years, plasmonic interferometer arouses great interest due to its compact size and enhanced light-matter interaction. They have demonstrated attractive applications in biomolecule sensing, optical modulation/switching, and material characterization, etc. In this work, we first propose a practical far-field method to extract the intrinsic phase dispersion, revealing important phase information during interactions among free-space light, nanostructure, and SPs. The proposed approach is confirmed by both simulation and experiment. Then we design novel plasmonic interferometer structure for sensitive optical sensing applications. To overcome two major limitations suffered by previously reported double-slit plasmonic Mach-Zehnder interferometer (PMZI), two new schemes are proposed and investigated. (1) A PMZI based on end-fire coupling improves the SP coupling efficiency and enhance the interference contrast more than 50 times. (2) In another design, a multi-layered metal-insulator-metal PMZI releases the requirement for single-slit illumination, which enables sensitive, high-throughput sensing applications based on intensity modulation. We develop a sensitive, low-cost and high-throughput biosensing platform based on intensity modulation using ring-hole plasmonic interferometers. This biosensor is then integrated with cell-phone-based microscope, which is promising to develop a portable sensor for point-of-care diagnostics, epidemic disease control and food safety monitoring.

  2. Vibrational dephasing in matter-wave interferometers

    NASA Astrophysics Data System (ADS)

    Rembold, A.; Schütz, G.; Röpke, R.; Chang, W. T.; Hwang, I. S.; Günther, A.; Stibor, A.

    2017-03-01

    Matter-wave interferometry is a highly sensitive tool to measure small perturbations in a quantum system. This property allows the creation of precision sensors for dephasing mechanisms such as mechanical vibrations. They are a challenge for phase measurements under perturbing conditions that cannot be perfectly decoupled from the interferometer, e.g. for mobile interferometric devices or vibrations with a broad frequency range. Here, we demonstrate a method based on second-order correlation theory in combination with Fourier analysis, to use an electron interferometer as a sensor that precisely characterizes the mechanical vibration spectrum of the interferometer. Using the high spatial and temporal single-particle resolution of a delay line detector, the data allows to reveal the original contrast and spatial periodicity of the interference pattern from ‘washed-out’ matter-wave interferograms that have been vibrationally disturbed in the frequency region between 100 and 1000 Hz. Other than with electromagnetic dephasing, due to excitations of higher harmonics and additional frequencies induced from the environment, the parts in the setup oscillate with frequencies that can be different to the applied ones. The developed numerical search algorithm is capable to determine those unknown oscillations and corresponding amplitudes. The technique can identify vibrational dephasing and decrease damping and shielding requirements in electron, ion, neutron, atom and molecule interferometers that generate a spatial fringe pattern on the detector plane.

  3. Differential Phase Mode with the Keck Interferometer

    NASA Technical Reports Server (NTRS)

    Akeson, Rachel; Swain, Mark

    2000-01-01

    We describe the differential phase mode of the Keck Interferometer. The scientific goal of this mode is the direct detection and spectroscopic characterization of hot, Jupiter mass planets. We describe the differential phase effect, the basic observational mode, and the expected differential phase signatures for the extrasolar planets discovered through radial velocity searches.

  4. Stepping optical path difference in an interferometer

    NASA Technical Reports Server (NTRS)

    Schindler, R. A.

    1976-01-01

    Stepping method permits higher amplitude modulation of secondary mirror of Fourier interferometer. Amplitude of mirror motion is limited only by available voltage drive on error-correcting actuator. Closed-loop controller provides servo error voltage linearly proportional to offset from proper null position. Bidirectional counter serves to count number of reference laser fringes offset from null position.

  5. An overview of the Keck Interferometer Nuller

    NASA Technical Reports Server (NTRS)

    Serabyn, Eugen

    2003-01-01

    The first high dynamic range interferometry mode planned to come on line at the Keck Observatory is mid-infrared nulling interferometry. In this paper, an overview is given of the goals and experimental configuration of the Keck Interferometer Nuller (KIN).

  6. The effect of rotations on Michelson interferometers

    SciTech Connect

    Maraner, Paolo

    2014-11-15

    In the contest of the special theory of relativity, it is shown that uniform rotations induce a phase shift in Michelson interferometers. The effect is second order in the ratio of the interferometer’s speed to the speed of light, further suppressed by the ratio of the interferometer’s arms length to the radius of rotation and depends on the interferometer’s position in the co-rotating frame. The magnitude of the phase shift is just beyond the sensitivity of turntable rotated optical resonators used in present tests of Lorentz invariance. It grows significantly large in Earth’s rotated kilometer-scale Fabry–Perot enhanced interferometric gravitational-wave detectors where it appears as a constant bias. The effect can provide the means of sensing center and radius of rotations. - Highlights: • Rotations induce a phase shift in Michelson interferometers. • Earth’s rotation induces a constant bias in Michelson interferometers. • Michelson interferometers can be used to sense center and radius of rotations.

  7. Berkeley heterodyne interferometer. [for IR stellar observations

    NASA Technical Reports Server (NTRS)

    Betz, A.

    1975-01-01

    A prototype heterodyne stellar interferometer has been built in order to demonstrate the feasibility of heterodyne techniques in measuring angular diameters of bright infrared stars. The first system tests were performed in December 1972. Attention is given to investigations concerning the possibility that optical air turbulence within the structure of the solar telescope employed can possibly destroy the phase coherence of the fringe signals.

  8. Fiber optic interferometer as a security element

    NASA Astrophysics Data System (ADS)

    Nedoma, Jan; Zboril, Ondrej; Fajkus, Marcel; Cubik, Jakub; Zavodny, Petr; Novak, Martin; Bednarek, Lukas; Martinek, Radek; Vasinek, Vladimir

    2016-04-01

    Interferometric sensors can be categorized as highly sensitive and precise devices with series inconsiderable benefits from the possibility of using standard telecommunication fibers. They can be measured even small changes in the deformation of shapes in time, changes in temperature, pressure, voltage, vibration, electric field, etc. The basic idea, which is described in this article is the usage of the interferometer as a security and monitoring component, which offers a solution for securing of closed spaces, especially before unwanted entries. Its primary task is to detect intrusions - disrupting the integrity of the transparent window area due to vibration response. The base of the solution is a Mach-Zehnder interferometer, which consists of two arms in the power distribution ratio of 1:1, consisting of the SM optical fiber excited by a DFB laser. The interferometer is working on the wavelength of 1550 nm. The resulting signal is registered as a result of interference of optical beams from the reference and sensor arm. Realized measuring scheme was terminated optical receiver comprising PbSe detector. Below described experimental measurements have shown that implemented interferometer has a sufficient value of the signal to noise ratio (SNR) and is able to detect very weak signals in a wide frequency range from tens of Hz to kHz units. The signal was processed by applications developed for the amplitude-frequency spectrum. Evaluated was the maximum amplitude of the signal and compared to the noise. The results were verified by retesting the assembled prototype.

  9. Visibility science operations with the Keck Interferometer

    NASA Technical Reports Server (NTRS)

    Wizinowich, P.; Akeson, R.; Colavita, M.; Gathright, J.; Appleby, E.; Bell, J.; Booth, A.; Dahl, W.; Hrynevych, M; Lynn, I.; Millan-Gabet, R.; Neyman, C.; Rudeen, A.; Saloga, T.; Summers, K.; Tsubota, K.

    2004-01-01

    The visibility science mode of the Keck Interferometer fully transitioned into operations with the successful completion of its operational readiness review in April, 2004. The goal of this paper is to describe this science mode and the operations structure that supports it.

  10. Keck Interferometer autoaligner : algorithms and techniques

    NASA Technical Reports Server (NTRS)

    Hrynevych, Michael A.; Tsubota, Kevin; Smythe, Robert; Dahla, Wayne; Bella, Jim; Colavita, M. Mark; Gathright, John; Meggars, Forest; Neyman, Christoper; Rudeen, Andy; van Belle, Gerard; Wizinowich, Peter

    2004-01-01

    The Keck Interferometer includes an autoalignment system consisting of pop-up targets located at strategic locations along the beam trains of each arm of the instrument along with a sensor and control system. We briefly describe the hardware of the system and then proceed to a description of the two operational modes of the system.

  11. The StarLight Space Interferometer

    NASA Technical Reports Server (NTRS)

    Folkner, William; Shao, Michael; Gorham, Peter

    2004-01-01

    Two papers describe the StarLight space interferometer a Michelson interferometer that would be implemented by two spacecraft flying in formation. The StarLight formation flying interferometer project has been testing and demonstrating engineering concepts for a new generation of space interferometers that would be employed in a search for extrasolar planets and in astrophysical investigations. As described in the papers, the original StarLight concept called for three spacecraft, and the main innovation embodied is a modification that makes it possible to reduce complexity by eliminating the third spacecraft. The main features of the modification are (1) introduction of an optical delay line on one spacecraft and (2) controlling the flying formation such that the two spacecraft are located at two points along a specified parabola so as to define the required baseline of specified length (which could be varied up to 125 m) perpendicular to the axis of the parabola. One of the papers presents a detailed description of the optical layout and discusses computational modeling of the performance; the other paper presents an overview of the requirements for operation and design, the overall architecture, and subsystems.

  12. Ramsey-Bordé interferometer for electrons

    NASA Astrophysics Data System (ADS)

    Marzlin, Karl-Peter

    2013-10-01

    A scheme to realize an electron interferometer using low-intensity, bichromatic laser pulses as beam splitter is proposed. The splitting process is based on a modification of the Kapitza-Dirac effect, which produces a momentum kick for electrons with a specific initial momentum. A full interferometric setup in Ramsey-Bordé configuration is theoretically analyzed.

  13. Thermal Noise in the Initial LIGO Interferometers

    NASA Astrophysics Data System (ADS)

    Gillespie, Aaron D.

    1995-01-01

    Gravitational wave detectors capable of detecting broadband gravitational wave bursts with a strain amplitude sensitivity near 10^{-21} at frequencies around 100 Hz are currently under construction by the LIGO (Laser Interferometer Gravitational-wave Observatory) and VIRGO groups. One challenge facing these groups is how to detect the motion of the center of an inertial mass to a precision of 10^{-18} m when the mass consists of atoms each of which individually moves much more than that due to thermal energy. The uncertainty in the interferometer's measurement due to these thermal motions is called thermal noise. This thesis describes the thermal noise of the initial LIGO detectors. The thermal noise was analyzed by modelling the normal modes of the test mass suspension system as harmonic oscillators with dissipation and applying the fluctuation dissipation theorem. The dissipation of all modes which contribute significant thermal noise to the interferometer was measured and from these measurements the total thermal noise was estimated. The frequency dependence of the dissipation of the pendulum mode was characterized from measurements of the violin modes. A steel music wire suspension system was found to meet the goals of the initial LIGO detectors. A mathematical technique was developed which relates the energy in each vibrational mode to the motion of the mirror surface measured by the interferometer. Modes with acoustic wavelengths greater than the laser beam spot size can contribute significant thermal noise to the interferometer measurements. The dissipation of the test masses of LIGO's 40 -m interferometer at Caltech was investigated, and a technique for suspending and controlling the test masses which lowered the dissipation and met the thermal noise goals of the initial LIGO detector was developed. New test masses were installed in the 40-m interferometer resulting in improved noise performance. The implications of thermal noise to detecting gravitational

  14. A Software Tool for Processing the Displacement Time Series Extracted from Raw Radar Data

    NASA Astrophysics Data System (ADS)

    Coppi, Francesco; Gentile, Carmelo; Paolo Ricci, Pier

    2010-05-01

    The application of high-resolution radar waveform and interferometric principles recently led to the development of a microwave interferometer, suitable to simultaneously measuring the (static or dynamic) deflection of several points on a large structure. From the technical standpoint, the sensor is a Stepped Frequency Continuous Wave (SF-CW), coherent radar, operating in the Ku frequency band. In the paper, the main procedures adopted to extract the deflection time series from raw radar data and to assess the quality of data are addressed, and the MATLAB toolbox developed is described. Subsequently, other functions implemented in the software tool (e.g. evaluation of the spectral matrix of the deflection time-histories, identification of natural frequencies and operational mode shapes evaluation) are described and the application to data recorded on full-scale bridges is exemplified.

  15. Miniaturized Ka-Band Dual-Channel Radar

    NASA Technical Reports Server (NTRS)

    Hoffman, James P.; Moussessian, Alina; Jenabi, Masud; Custodero, Brian

    2011-01-01

    Smaller (volume, mass, power) electronics for a Ka-band (36 GHz) radar interferometer were required. To reduce size and achieve better control over RFphase versus temperature, fully hybrid electronics were developed for the RF portion of the radar s two-channel receiver and single-channel transmitter. In this context, fully hybrid means that every active RF device was an open die, and all passives were directly attached to the subcarrier. Attachments were made using wire and ribbon bonding. In this way, every component, even small passives, was selected for the fabrication of the two radar receivers, and the devices were mounted relative to each other in order to make complementary components isothermal and to isolate other components from potential temperature gradients. This is critical for developing receivers that can track each other s phase over temperature, which is a key mission driver for obtaining ocean surface height. Fully hybrid, Ka-band (36 GHz) radar transmitter and dual-channel receiver were developed for spaceborne radar interferometry. The fully hybrid fabrication enables control over every aspect of the component selection, placement, and connection. Since the two receiver channels must track each other to better than 100 millidegrees of RF phase over several minutes, the hardware in the two receivers must be "identical," routed the same (same line lengths), and as isothermal as possible. This level of design freedom is not possible with packaged components, which include many internal passive, unknown internal connection lengths/types, and often a single orientation of inputs and outputs.

  16. Accurate measurement of interferometer group delay using field-compensated scanning white light interferometer.

    PubMed

    Wan, Xiaoke; Wang, Ji; Ge, Jian

    2010-10-10

    Interferometers are key elements in radial velocity (RV) experiments in astronomy observations, and accurate calibration of the group delay of an interferometer is required for high precision measurements. A novel field-compensated white light scanning Michelson interferometer is introduced as an interferometer calibration tool. The optical path difference (OPD) scanning was achieved by translating a compensation prism, such that even if the light source were in low spatial coherence, the interference stays spatially phase coherent over a large interferometer scanning range. In the wavelength region of 500-560 nm, a multimode fiber-coupled LED was used as the light source, and high optical efficiency was essential in elevating the signal-to-noise ratio of the interferogram signal. The achromatic OPD scanning required a one-time calibration, and two methods using dual-laser wavelength references and an iodine absorption spectrum reference were employed and cross-verified. In an experiment measuring the group delay of a fixed Michelson interferometer, Fourier analysis was employed to process the interferogram data. The group delay was determined at an accuracy of 1×10(-5), and the phase angle precision was typically 2.5×10(-6) over the wide wavelength region.

  17. Compact in-line laser radial shear interferometer

    NASA Technical Reports Server (NTRS)

    Shukla, R. P.; Moghbel, M.; Venkateswarlu, P.

    1992-01-01

    A compact in-line radial shearing interferometer using laser as a light source is presented. The interferometer is made out of a cube-type beam splitter so that the two opposite surfaces are generated with different curvatures while the normal to the entrance and exit surfaces are in the same line. The interferometer is simple to make and easy to align. Aberration analysis of the interferometer is also presented. Some applications of the interferometer for testing lenses and infrared optical systems and for accessing the quality of an emerging wave front from the exit slit of a monochromator are suggested.

  18. The millimeter-wave bolometric interferometer

    NASA Astrophysics Data System (ADS)

    Gault, Amanda Charlotte

    The Millimeter-wave Bolometric Interferometer (MBI) is a technology demonstrator for future searches for the B-mode polarization of the Cosmic Microwave Background (CMB). If observed, B-modes would be a direct probe of the energy scale of inflation, an energy scale that is impossible to reach with even the most sophisticated particle accelerators. In this thesis, I outline the technology differences between MBI and conventional interferometers, including the Faraday effect phase modulators (FPM) used both to control systematic effects and to allow for phase sensitive detection of signals. MBI is a four element adding interferometer with a Fizeau optical beam combiner. This allows simple scaling of the instrument to a large numbers of baselines without requiring complicated pair-wise correlations of signals. Interferometers have an advantage over imaging telescopes when measuring the CMB power spectrum as each baseline is sensitive to a single Fourier mode (angular scale) on the sky. Recovering individual baseline information with this combination scheme requires phase modulating the signal from each antenna. MBI performs this modulation with Faraday effect phase modulators. In these novel cryogenic devices a modulated magnetic field switches the phase of a millimeter-wave RF signal by +/- 90 degrees at frequencies up to a few Hertz. MBI's second season of observations occurred in the winter of 2009 at Pine Bluff Observatory a few miles west of Madsion, WI. We successfully observed interference fringes of a microwave test source located in the far field of the instrument that agree well with those expected from simulations. MBI has inspired a second generation bolometric interferometer, QUBIC, which will have hundreds of antennas and thousands of detectors. When it deploys in 2015, it will be sensitive enough to search for B-mode signals from the CMB.

  19. Interception of LPI Radar Signals

    DTIC Science & Technology

    1991-11-01

    AD-A246 315!I! I!! II I’ IIi INTERCEPTION OF LPI RADAR SIGNALS (U) by Jim P.Y. Lee DEFENCE RESEARCH ESTABLISHMENT OTTAWA TECHNICAL NOTE 91-23 Canadd...November 1991Ottawa 92-041269’ 2 2 18 II.2t1111111I 111111! !_ 1+1 efrc nadonds INTERCEPTION OF LPI RADAR SIGNALS (U) by Jim P.Y. Lee Radar E"Sect&ion... radar may employ against current EW receivers. The general conclusion is that it is possible to design a LPI radar which is effective against current

  20. Coherent and incoherent scatter radar observations during intense mid-latitude spread F

    NASA Astrophysics Data System (ADS)

    Swartz, Wesley E.; Kelley, Michael C.; Makela, Jonathan J.; Collins, Stephen C.; Kudeki, Erhan; Franke, Steve; Urbina, Julio; Aponte, Nestor; Sulzer, Michael P.; González, Sixto A.

    2000-09-01

    An intense mid-latitude spread-F event occurred over Puerto Rico during the night of February 17, 1998. Simultaneous observations were made with the Cornell University Portable Radar Interferometer (CUPRI) located near Isabela, PR, the University of Illinois VHF radar located at Salinas, PR, GPS receivers at Isabela and St. Croix, measuring total electron content, the Arecibo incoherent scatter radar, and the Cornell All-Sky imager located at the Arecibo Observatory. This was the first time that such a broad range of complementary instrumentation captured a mid-latitude spread-F space weather event. It was the first (and still only) time that a spread-F event over the Caribbean exhibited large Doppler shifts in the VHF spectra. This event was characterized with multiple filaments that initially produced receding Doppler velocities exceeding 300 m/s as seen by CUPRI and the Illinois radar. The Arecibo incoherent scatter radar recorded line-of-sight velocities exceeding 100 m/s that moved the F-layer peak to over 400-km altitude. Airglow images of 630.0 nm emissions from F-region heights showed depleted structures oriented southeast to northwest. The large velocities observed with the radars suggest that we caught this event in a stage of explosive development. It is interesting that the first fully documented Caribbean event occurred during a magnetically active period.

  1. Synthetic Aperture Radar Interferometry

    NASA Technical Reports Server (NTRS)

    Rosen, P. A.; Hensley, S.; Joughin, I. R.; Li, F.; Madsen, S. N.; Rodriguez, E.; Goldstein, R. M.

    1998-01-01

    Synthetic aperture radar interferometry is an imaging technique for measuring the topography of a surface, its changes over time, and other changes in the detailed characteristics of the surface. This paper reviews the techniques of interferometry, systems and limitations, and applications in a rapidly growing area of science and engineering.

  2. Netted LPI RADARs

    DTIC Science & Technology

    2011-09-01

    Characteristics ALQ-172 B-52G/H Self- protection Track/search radar jamming, steerable jam beams , software programmable, phased array antenna ...bore sight: knowing the pattern of the antenna’s gain, two or more intercepts within the antenna main beam are sufficient to determine the...14 a. Low Level Antenna Sidelobes .............14 b. Antenna Scan Patterns ...................18 4. Carrier Frequency Selection

  3. Rain radar instrument definition

    NASA Astrophysics Data System (ADS)

    Vincent, Nicolas; Chenebault, J.; Suinot, Noel; Mancini, Paolo L.

    1996-12-01

    As a result of a pre-phase a study, founded by ESA, this paper presents the definition of a spaceborne Rain Radar, candidate instrument for earth explorer precipitation mission. Based upon the description of user requirements for such a dedicated mission, a mission analysis defines the most suitable space segment. At system level, a parametric analysis compares pros and cons of instrument concepts associated with rain rate retrieval algorithms in order to select the most performing one. Several trade-off analysis at subsystem level leads then to the definition of the proposed design. In particular, as pulse compression is implemented in order to increase the radar sensitivity, the selected method to achieve a pulse response with a side-lobe level below--60 dB is presented. Antenna is another critical rain radar subsystem and several designs are com pared: direct radiating array, single or dual reflector illuminated by single or dual feed arrays. At least, feasibility of centralized amplification using TWTA is compared with criticality of Tx/Rx modules for distributed amplification. Mass and power budgets of the designed instrument are summarized as well as standard deviations and bias of simulated rain rate retrieval profiles. The feasibility of a compliant rain radar instrument is therefore demonstrated.

  4. Frequency Diverse Array Radar

    DTIC Science & Technology

    2010-09-01

    the methods for electronic scanning of antenna systems. Techniques that have been studied in this connection include frequency variation, phase shift...an array antenna instantaneously into a desired direction where no mechanical mechanism is involved in the scanning process. Electronic scanning... methods including phase scanning, time delay scanning, and frequency scanning have been used in various radar applications; however new and cheaper

  5. Passive MIMO Radar Detection

    DTIC Science & Technology

    2013-09-01

    Hypothesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 3.3.3 Dependence on SNR...71 4.3.3 Dependence on SNR and DNR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 4.4 Interpretations...described as a passive radar network. The topology of such networks is described as bistatic, multistatic, or multiple-input multiple-output, depending on

  6. Passive bistatic radar analysis

    NASA Astrophysics Data System (ADS)

    O'Hagan, Daniel W.; Kuschel, H.; Schiller, Joachim

    2009-06-01

    Passive Bistatic Radar (PBR) research is at its zenith with several notable PBR systems currently operational, or available for deployment. Such PBRs include the Manastash Ridge Radar (MRR) developed for and by academia; Silent Sentry developed as a commercial concern by Lockheed Martin; and Homeland Alerter (HA100) also a commercial system developed by Thales. However at present, despite the existence of numerous PBR prototypes, take up of commercial passive radar technology remains slow. This is due in part to technology immaturity, in part to politics, and particularly due to the fact that monostatic radars perform so well. If PBRs are to enjoy longevity as a viable technology then it is imperative that they address certain niche application areas, with the aforementioned MRR being one prime example of this. The focus of this paper will be an analysis of a PBR system that utilised FM radio signals of opportunity to detect aircraft targets with an RCS generally not lower than 20 m2. The paper will demonstrate the theoretical detection coverage of an FM based PBR operating in a severe interference environment.

  7. Impulse radar studfinder

    DOEpatents

    McEwan, T.E.

    1995-10-10

    An impulse radar studfinder propagates electromagnetic pulses and detects reflected pulses from a fixed range. Unmodulated pulses, about 200 ps wide, are emitted. A large number of reflected pulses are sampled and averaged. Background reflections are subtracted. Reflections from wall studs or other hidden objects are detected and displayed using light emitting diodes. 9 figs.

  8. Impulse radar studfinder

    DOEpatents

    McEwan, Thomas E.

    1995-01-01

    An impulse radar studfinder propagates electromagnetic pulses and detects reflected pulses from a fixed range. Unmodulated pulses, about 200 ps wide, are emitted. A large number of reflected pulses are sampled and averaged. Background reflections are subtracted. Reflections from wall studs or other hidden objects are detected and displayed using light emitting diodes.

  9. A compact semiconductor digital interferometer and its applications

    NASA Astrophysics Data System (ADS)

    Britsky, Oleksander I.; Gorbov, Ivan V.; Petrov, Viacheslav V.; Balagura, Iryna V.

    2015-05-01

    The possibility of using semiconductor laser interferometers to measure displacements at the nanometer scale was demonstrated. The creation principles of miniature digital Michelson interferometers based on semiconductor lasers were proposed. The advanced processing algorithm for the interferometer quadrature signals was designed. It enabled to reduce restrictions on speed of measured movements. A miniature semiconductor digital Michelson interferometer was developed. Designing of the precision temperature stability system for miniature low-cost semiconductor laser with 0.01ºС accuracy enabled to use it for creation of compact interferometer rather than a helium-neon one. Proper firmware and software was designed for the interferometer signals real-time processing and conversion in to respective shifts. In the result the relative displacement between 0-500 mm was measured with a resolution of better than 1 nm. Advantages and disadvantages of practical use of the compact semiconductor digital interferometer in seismometers for the measurement of shifts were shown.

  10. High resolution heterodyne interferometer without detectable periodic nonlinearity.

    PubMed

    Joo, Ki-Nam; Ellis, Jonathan D; Buice, Eric S; Spronck, Jo W; Schmidt, Robert H Munnig

    2010-01-18

    A high resolution heterodyne laser interferometer without periodic nonlinearity for linear displacement measurements is described. It uses two spatially separated beams with an offset frequency and an interferometer configuration which has no mixed states to prevent polarization mixing. In this research, a simple interferometer configuration for both retroreflector and plane mirror targets which are both applicable to industrial applications was developed. Experimental results show there is no detectable periodic nonlinearity for both of the retro-reflector interferometer and plane mirror interferometer to the noise level of 20 pm. Additionally, the optical configuration has the benefit of doubling the measurement resolution when compared to its respective traditional counterparts. Because of non-symmetry in the plane mirror interferometer, a differential plane mirror interferometer to reduce the thermal error is also discussed.

  11. An MSK Radar Waveform

    NASA Technical Reports Server (NTRS)

    Quirk, Kevin J.; Srinivasan, Meera

    2012-01-01

    The minimum-shift-keying (MSK) radar waveform is formed by periodically extending a waveform that separately modulates the in-phase and quadrature- phase components of the carrier with offset pulse-shaped pseudo noise (PN) sequences. To generate this waveform, a pair of periodic PN sequences is each passed through a pulse-shaping filter with a half sinusoid impulse response. These shaped PN waveforms are then offset by half a chip time and are separately modulated on the in-phase and quadrature phase components of an RF carrier. This new radar waveform allows an increase in radar resolution without the need for additional spectrum. In addition, it provides self-interference suppression and configurable peak sidelobes. Compared strictly on the basis of the expressions for delay resolution, main-lobe bandwidth, effective Doppler bandwidth, and peak ambiguity sidelobe, it appears that bi-phase coded (BPC) outperforms the new MSK waveform. However, a radar waveform must meet certain constraints imposed by the transmission and reception of the modulation, as well as criteria dictated by the observation. In particular, the phase discontinuity of the BPC waveform presents a significant impediment to the achievement of finer resolutions in radar measurements a limitation that is overcome by using the continuous phase MSK waveform. The phase continuity, and the lower fractional out-of-band power of MSK, increases the allowable bandwidth compared with BPC, resulting in a factor of two increase in the range resolution of the radar. The MSK waveform also has been demonstrated to have an ambiguity sidelobe structure very similar to BPC, where the sidelobe levels can be decreased by increasing the length of the m-sequence used in its generation. This ability to set the peak sidelobe level is advantageous as it allows the system to be configured to a variety of targets, including those with a larger dynamic range. Other conventionally used waveforms that possess an even greater

  12. Automatic null ellipsometry with an interferometer

    SciTech Connect

    Watkins, Lionel R.

    2009-11-10

    A new approach to automatic null ellipsometry is described in which the analyzer of a traditional polarizer compensator sample analyzer (PCSA) null ellipsometer is replaced with a heterodyne Michelson interferometer. One arm of this interferometer is modified such that it produces a fixed, linearly polarized reference beam, irrespective of the input polarization state. This beam is recombined interferometrically with the measurement beam and spatially separated into its p and s polarizations. The relative phase of the resulting temporal fringes is a linear function of the polarizer azimuthal angle P, and thus this component can be driven to its null position without iteration. Once at null, the azimuthal angle of the reflected, linearly polarized light is trivially determined from the relative amplitude of the fringes. Measurements made with this instrument on a native oxide film on a silicon wafer were in excellent agreement with those made with a traditional PCSA null ellipsometer.

  13. An adaptive interferometer for optical testing .

    NASA Astrophysics Data System (ADS)

    Pariani, G.; Colella, L.; Bertarelli, C.; Aliverti, M.; Riva, M.; Bianco, A.

    Interferometry is a well-established technique to test optical elements. However, its use is challenging in the case of free-form and aspheric elements, due to the lack of the reference optics. The proposed idea concerns the development of a versatile interferometer, where its reference arm is equipped with a reprogrammable Computer Generated Hologram. This principle takes advantage from our study on photochromic materials for optical applications, which shows a strong and reversible modulation of transparency in the visible region. The encoding of the desired hologram can be done off-line, or directly into the interferometer, and different patterns may be realized sequentially after the erasing of the previous hologram. We report on the present state of the research and on the future perspectives. skip=5pt

  14. A continuous cold atomic beam interferometer

    SciTech Connect

    Xue, Hongbo; Feng, Yanying Yan, Xueshu; Jiang, Zhikun; Chen, Shu; Wang, Xiaojia; Zhou, Zhaoying

    2015-03-07

    We demonstrate an atom interferometer that uses a laser-cooled continuous beam of {sup 87}Rb atoms having velocities of 10–20 m/s. With spatially separated Raman beams to coherently manipulate the atomic wave packets, Mach–Zehnder interference fringes are observed at an interference distance of 2L = 19 mm. The apparatus operates within a small enclosed area of 0.07 mm{sup 2} at a bandwidth of 190 Hz with a deduced sensitivity of 7.8×10{sup −5} rad/s/√(Hz) for rotations. Using a low-velocity continuous atomic source in an atom interferometer enables high sampling rates and bandwidths without sacrificing sensitivity and compactness, which are important for applications in real dynamic environments.

  15. Interferometer for Low-Uncertainty Vector Metrology

    NASA Technical Reports Server (NTRS)

    Toland, Ronald W.; Leviton, Douglas B.

    2006-01-01

    A simplified schematic diagram of a tilt-sensing unequal-path interferometer set up to measure the orientation of the normal vector of one surface of a cube mounted on a structure under test is described herein. This interferometer has been named a "theoferometer" to express both its interferometric nature and the intention to use it instead of an autocollimating theodolite. The theoferometer optics are mounted on a plate, which is in turn mounted on orthogonal air bearings for near-360 rotation in azimuth and elevation. Rough alignment of the theoferometer to the test cube is done by hand, with fine position adjustment provided by a tangent arm drive using linear inchwormlike motors.

  16. Phase-shifting point diffraction interferometer

    DOEpatents

    Medecki, Hector

    1998-01-01

    Disclosed is a point diffraction interferometer for evaluating the quality of a test optic. In operation, the point diffraction interferometer includes a source of radiation, the test optic, a beam divider, a reference wave pinhole located at an image plane downstream from the test optic, and a detector for detecting an interference pattern produced between a reference wave emitted by the pinhole and a test wave emitted from the test optic. The beam divider produces separate reference and test beams which focus at different laterally separated positions on the image plane. The reference wave pinhole is placed at a region of high intensity (e.g., the focal point) for the reference beam. This allows reference wave to be produced at a relatively high intensity. Also, the beam divider may include elements for phase shifting one or both of the reference and test beams.

  17. Phase-shifting point diffraction interferometer

    DOEpatents

    Medecki, H.

    1998-11-10

    Disclosed is a point diffraction interferometer for evaluating the quality of a test optic. In operation, the point diffraction interferometer includes a source of radiation, the test optic, a beam divider, a reference wave pinhole located at an image plane downstream from the test optic, and a detector for detecting an interference pattern produced between a reference wave emitted by the pinhole and a test wave emitted from the test optic. The beam divider produces separate reference and test beams which focus at different laterally separated positions on the image plane. The reference wave pinhole is placed at a region of high intensity (e.g., the focal point) for the reference beam. This allows reference wave to be produced at a relatively high intensity. Also, the beam divider may include elements for phase shifting one or both of the reference and test beams. 8 figs.

  18. Adaptive DFT-based Interferometer Fringe Tracking

    NASA Technical Reports Server (NTRS)

    Wilson, Edward; Pedretti, Ettore; Bregman, Jesse; Mah, Robert W.; Traub, Wesley A.

    2004-01-01

    An automatic interferometer fringe tracking system has been developed, implemented, and tested at the Infrared Optical Telescope Array (IOTA) observatory at Mt. Hopkins, Arizona. The system can minimize the optical path differences (OPDs) for all three baselines of the Michelson stellar interferometer at IOTA. Based on sliding window discrete Fourier transform (DFT) calculations that were optimized for computational efficiency and robustness to atmospheric disturbances, the algorithm has also been tested extensively on off-line data. Implemented in ANSI C on the 266 MHz PowerPC processor running the VxWorks real-time operating system, the algorithm runs in approximately 2.0 milliseconds per scan (including all three interferograms), using the science camera and piezo scanners to measure and correct the OPDs. The adaptive DFT-based tracking algorithm should be applicable to other systems where there is a need to detect or track a signal with an approximately constant-frequency carrier pulse.

  19. Data Processing for Atmospheric Phase Interferometers

    NASA Technical Reports Server (NTRS)

    Acosta, Roberto J.; Nessel, James A.; Morabito, David D.

    2009-01-01

    This paper presents a detailed discussion of calibration procedures used to analyze data recorded from a two-element atmospheric phase interferometer (API) deployed at Goldstone, California. In addition, we describe the data products derived from those measurements that can be used for site intercomparison and atmospheric modeling. Simulated data is used to demonstrate the effectiveness of the proposed algorithm and as a means for validating our procedure. A study of the effect of block size filtering is presented to justify our process for isolating atmospheric fluctuation phenomena from other system-induced effects (e.g., satellite motion, thermal drift). A simulated 24 hr interferometer phase data time series is analyzed to illustrate the step-by-step calibration procedure and desired data products.

  20. Michelson interferometer for precision angle measurement.

    PubMed

    Ikram, M; Hussain, G

    1999-01-01

    An angle-measuring technique based on an optical interferometer is reported. The technique exploits a Michelson interferometric configuration in which a right-angle prism and a glass strip are introduced into a probe beam. Simultaneous rotation of both components along an axis results in an optical path difference between the reference and the probe beams. In a second arrangement two right-angle prisms and glass strips are introduced into two beams of a Michelson interferometer. The prisms and the strips are rotated simultaneously to introduce an optical path difference between the two beams. In our arrangement, optimization of various parameters makes the net optical path difference between the two beams approximately linear for a rotation as great as +/-20 degrees . Results are simulated that show an improvement of 2-3 orders of magnitude in error and nonlinearity compared with a previously reported technique.

  1. A multipulsed dynamic diffraction moire interferometer

    NASA Astrophysics Data System (ADS)

    Deason, V. A.; Ward, M. B.

    A system capable of generating several tens of diffraction moire interferograms at rates on the order of 1 MHz is described. The interferometer consists of a specially modified, segmented ruby rod laser capable of producing a long train of 40-mJ pulses each with a width on the order of 20 to 50 ns. The interferograms are recorded on film using a high speed turbine camera capable of 2,000,000 frames per second for a total record of 80 frames. The interferometer is used in conjunction with any of several devices for impulsively loading a variety of materials so as to study dynamic material deformation, fracture, delamination, or other response to dynamic stress. This apparatus is the latest in a series of dynamic diffraction moire systems built at the Idaho National Engineering Laboratory. Dynamic moire studies of Colorado oil shale are briefly discussed.

  2. A Multipulsed Dynamic Diffraction Moire Interferometer

    NASA Astrophysics Data System (ADS)

    Deason, Vance A.; Ward, Michael B.

    1990-04-01

    A system capable of generating several tens of diffraction moire interferograms at rates on the order of 1 MHz is described. The interferometer consists of a specially modified, segmented ruby rod laser capable of producing a long train of 40-mJ pulses each with a width on the order of 20 to 50 ns. The interferograms are recorded on film using a high speed turbine camera capable of 2,000,000 frames per second for a total record of 80 frames. The interferometer is used in conjunction with any of several devices for impulsively loading a variety of materials so as to study dynamic material deformation, fracture, delamination, or other response to dynamic stress. This apparatus is the latest in a series of dynamic diffraction moire systems built at the Idaho National Engineering Laboratory.

  3. Bright Solitonic Matter-Wave Interferometer

    NASA Astrophysics Data System (ADS)

    McDonald, G. D.; Kuhn, C. C. N.; Hardman, K. S.; Bennetts, S.; Everitt, P. J.; Altin, P. A.; Debs, J. E.; Close, J. D.; Robins, N. P.

    2014-07-01

    We present the first realization of a solitonic atom interferometer. A Bose-Einstein condensate of 1×104 atoms of rubidium-85 is loaded into a horizontal optical waveguide. Through the use of a Feshbach resonance, the s-wave scattering length of the Rb85 atoms is tuned to a small negative value. This attractive atomic interaction then balances the inherent matter-wave dispersion, creating a bright solitonic matter wave. A Mach-Zehnder interferometer is constructed by driving Bragg transitions with the use of an optical lattice colinear with the waveguide. Matter-wave propagation and interferometric fringe visibility are compared across a range of s-wave scattering values including repulsive, attractive and noninteracting values. The solitonic matter wave is found to significantly increase fringe visibility even compared with a noninteracting cloud.

  4. Accurate radio positions with the Tidbinbilla interferometer

    NASA Technical Reports Server (NTRS)

    Batty, M. J.; Gulkis, S.; Jauncey, D. L.; Rayner, P. T.

    1979-01-01

    The Tidbinbilla interferometer (Batty et al., 1977) is designed specifically to provide accurate radio position measurements of compact radio sources in the Southern Hemisphere with high sensitivity. The interferometer uses the 26-m and 64-m antennas of the Deep Space Network at Tidbinbilla, near Canberra. The two antennas are separated by 200 m on a north-south baseline. By utilizing the existing antennas and the low-noise traveling-wave masers at 2.29 GHz, it has been possible to produce a high-sensitivity instrument with a minimum of capital expenditure. The north-south baseline ensures that a good range of UV coverage is obtained, so that sources lying in the declination range between about -80 and +30 deg may be observed with nearly orthogonal projected baselines of no less than about 1000 lambda. The instrument also provides high-accuracy flux density measurements for compact radio sources.

  5. Radar Target Recognition Using Bispectrum Correlation

    DTIC Science & Technology

    2007-06-01

    21 2. Inverse Synthetic Aperture Radar ...................................................22 3. Range Profiles...characteristics need to be stored. 2. Inverse Synthetic Aperture Radar We often identify things based on pictures and Synthetic Aperture Radar (SAR) is an...By taking multiple discrete measurements while translating the radar , a larger effective aperture can be created. Inverse Synthetic Aperture Radar

  6. 51. View of upper radar scanner switch in radar scanner ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    51. View of upper radar scanner switch in radar scanner building 105 from upper catwalk level showing emanating waveguides from upper switch (upper one-fourth of photograph) and emanating waveguides from lower radar scanner switch in vertical runs. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

  7. Radar cross-sectional study using noise radar

    NASA Astrophysics Data System (ADS)

    Freundorfer, A. P.; Siddiqui, J. Y.; Antar, Y. M. M.

    2015-05-01

    A noise radar system is proposed with capabilities to measure and acquire the radar cross-section (RCS) of targets. The proposed system can cover a noise bandwidth of near DC to 50 GHz. The noise radar RCS measurements were conducted for selective targets like spheres and carpenter squares with and without dielectric bodies for a noise band of 400MHz-5000MHz. The bandwidth of operation was limited by the multiplier and the antennae used.

  8. 41. Perimeter acquisition radar building radar element and coaxial display, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    41. Perimeter acquisition radar building radar element and coaxial display, with drawing of typical antenna section. Drawing, from left to right, shows element, aluminum ground plane, cable connectors and hardware, cable, and back-up ring. Grey area is the concrete wall - Stanley R. Mickelsen Safeguard Complex, Perimeter Acquisition Radar Building, Limited Access Area, between Limited Access Patrol Road & Service Road A, Nekoma, Cavalier County, ND

  9. Support of Mark III Optical Interferometer

    DTIC Science & Technology

    1988-11-01

    error, and low visibility* pedestal, and the surface of a zerodur sphere attached to the mirror errors are not entirely consistent. as shown in Fig. 7...of’ stellar usually associated with the primary mirror of a large astronomical interferometers at Mt. Wilson Observatory. The first instrument...the two siderostats is directed toward the central building by fixed mirrors . These fixed mirrors are necessary to keep the polarization - vectors

  10. Large aperture ac interferometer for optical testing.

    PubMed

    Moore, D T; Murray, R; Neves, F B

    1978-12-15

    A 20-cm clear aperture modified Twyman-Green interferometer is described. The system measures phase with an AC technique called phase-lock interferometry while scanning the aperture with a dual galvanometer scanning system. Position information and phase are stored in a minicomputer with disk storage. This information is manipulated with associated software, and the wavefront deformation due to a test component is graphically displayed in perspective and contour on a CRT terminal.

  11. Broadband, Achromatic Twyman-Green Interferometer

    NASA Technical Reports Server (NTRS)

    Steimle, Lawrence J.

    1991-01-01

    Improved Twyman-Green interferometer used in wave-front testing optical components at wavelengths from 200 to 1,100 nm, without having to readjust focus when changing wavelength. Built to measure aberrations of light passing through optical filters. Collimating and imaging lenses of classical Twyman-Green configuration replaced by single spherical mirror. Field lens replaced by field mirror. Mirrors exhibit no axial chromatic aberration and made to reflect light efficiently over desired broad range of wavelengths.

  12. Digital phase-shifting point diffraction interferometer.

    PubMed

    Akondi, Vyas; Jewel, A R; Vohnsen, Brian

    2014-03-15

    A digital phase-shifting (PS) point diffraction interferometer is demonstrated with a transmitting liquid crystal spatial light modulator. This novel wavefront sensor allows tunability in the choice of pinhole size and eliminates the need for mechanically moving parts to achieve PS. It is shown that this wavefront sensor is capable of sensing Zernike aberrations introduced with a deformable mirror. The results obtained are compared with those of a commercial Hartmann-Shack wavefront sensor.

  13. Interferometer experiment on nimbus 3: preliminary results.

    PubMed

    Hanel, R; Conrath, B

    1969-09-19

    A Michelson interferometer spectrometer carried aboard the Nimbus 3 satellite, launched 14 April 1969, measured the spectrum between 400 and 2000 wave numbers with a resolution of 5 wave numbers. High-quality spectra have been obtained on a global scale, and preliminary results indicate that the absorption bands of carbon dioxide, water vapor, and ozone can be used to obtain vertical distributions of temperature, water vapor, and ozone.

  14. Bragg interferometer for gravity gradient measurements

    NASA Astrophysics Data System (ADS)

    D'Amico, G.; Borselli, F.; Cacciapuoti, L.; Prevedelli, M.; Rosi, G.; Sorrentino, F.; Tino, G. M.

    2016-06-01

    We report on the characterization of a dual cloud atom interferometer for gravity gradient measurements using third-order Bragg diffraction as atom optical elements. We study the dependence of the contrast and the gradiometer phase angle against the relevant experimental parameters and characterize the instrument sensitivity. We achieve a sensitivity to gravity gradient measurements of 2.6 ×10-8s-2 (26 E) after 2000 s of integration time.

  15. Optical tweezers based on polarization interferometer

    NASA Astrophysics Data System (ADS)

    Angelsky, Oleg V.; Maksimyak, Andrew P.; Maksimyak, Peter P.; Dominikov, Mykola M.

    2013-06-01

    In this paper, we propose optical tweezers based on a biaxial crystal. To control the movement of opaque particles, we use the shift polarization interferometer. The results of experimental study of laser tweezers are shown. We demonstrates movement of a microparticle of toner using singular-optical trap, rotate a particle due to orbital momentum, conversion of two traps when changing the plane of polarizer transmission and converging of two traps.

  16. Operational Funding for Optical and Infrared Interferometers

    DTIC Science & Technology

    2009-01-01

    constraining the central 0.1 pc of active galactic nuclei. These facilities are also ideal environments for hands-on observational astronomy ...MROI) and Large Binocular Telescope Interferometer (LBTI), which are under construction. These observatories carry out high angular resolution...Name Long Name References CHARA Array Center for High Angular Resolution Astronomy Array ten Brummelaar et al. 2005 (ApJ, 628, 453) ISI

  17. Kuiper Belt Mapping Radar

    NASA Technical Reports Server (NTRS)

    Freeman, A.; Nilsen, E.

    2001-01-01

    Since their initial discovery in 1992, to date only a relatively small number of Kuiper Belt Objects (KBO's) have been discovered. Current detection techniques rely on frame-to-frame comparisons of images collected by optical telescopes such as Hubble, to detect KBO's as they move against the background stellar field. Another technique involving studies of KBO's through occultation of known stars has been proposed. Such techniques are serendipitous, not systematic, and may lead to an inadequate understanding of the size, range, and distribution of KBO's. In this paper, a future Kuiper Belt Mapping Radar is proposed as a solution to the problem of mapping the size distribution, extent, and range of KBO's. This approach can also be used to recover radar albedo and object rotation rates. Additional information is contained in the original extended abstract.

  18. RADAR Reveals Titan Topography

    NASA Technical Reports Server (NTRS)

    Kirk, R. L.; Callahan, P.; Seu, R.; Lorenz, R. D.; Paganelli, F.; Lopes, R.; Elachi, C.

    2005-01-01

    The Cassini Titan RADAR Mapper is a K(sub u)-band (13.78 GHz, lambda = 2.17 cm) linear polarized RADAR instrument capable of operating in synthetic aperture (SAR), scatterometer, altimeter and radiometer modes. During the first targeted flyby of Titan on 26 October, 2004 (referred to as Ta) observations were made in all modes. Evidence for topographic relief based on the Ta altimetry and SAR data are presented here. Additional SAR and altimetry observations are planned for the T3 encounter on 15 February, 2005, but have not been carried out at this writing. Results from the T3 encounter relevant to topography will be included in our presentation. Data obtained in the Ta encounter include a SAR image swath

  19. Floor-plan radar

    NASA Astrophysics Data System (ADS)

    Falconer, David G.; Ueberschaer, Ronald M.

    2000-07-01

    Urban-warfare specialists, law-enforcement officers, counter-drug agents, and counter-terrorism experts encounter operational situations where they must assault a target building and capture or rescue its occupants. To minimize potential casualties, the assault team needs a picture of the building's interior and a copy of its floor plan. With this need in mind, we constructed a scale model of a single- story house and imaged its interior using synthetic-aperture techniques. The interior and exterior walls nearest the radar set were imaged with good fidelity, but the distal ones appear poorly defined and surrounded by ghosts and artifacts. The latter defects are traceable to beam attenuation, wavefront distortion, multiple scattering, traveling waves, resonance phenomena, and other effects not accounted for in the traditional (noninteracting, isotropic point scatterer) model for radar imaging.

  20. High-resolution coherent backscatter interferometric radar images of equatorial spread F using Capon's method

    NASA Astrophysics Data System (ADS)

    Rodrigues, Fabiano S.; de Paula, Eurico R.; Zewdie, Gebreab K.

    2017-03-01

    We present results of Capon's method for estimation of in-beam images of ionospheric scattering structures observed by a small, low-power coherent backscatter interferometer. The radar interferometer operated in the equatorial site of São Luís, Brazil (2.59° S, 44.21° W, -2.35° dip latitude). We show numerical simulations that evaluate the performance of the Capon method for typical F region measurement conditions. Numerical simulations show that, despite the short baselines of the São Luís radar, the Capon technique is capable of distinguishing localized features with kilometric scale sizes (in the zonal direction) at F region heights. Following the simulations, we applied the Capon algorithm to actual measurements made by the São Luís interferometer during a typical equatorial spread F (ESF) event. As indicated by the simulations, the Capon method produced images that were better resolved than those produced by the Fourier method. The Capon images show narrow (a few kilometers wide) scattering channels associated with ESF plumes and scattering regions spaced by only a few tens of kilometers in the zonal direction. The images are also capable of resolving bifurcations and the C shape of scattering structures.

  1. Fabry-Perot interferometer measurements of thermospheric neutral wind gradients and reversals at Arecibo

    NASA Technical Reports Server (NTRS)

    Friedman, J. F.; Herrero, F. A.

    1982-01-01

    Direct measurements of the meridional neutral winds in the thermosphere made with the Fabry-Perot interferometer at the Arecibo Observatory show the postmidnight meridional wind reversal that was inferred from previous incoherent scatter radar ion-drift data and airglow intensity maps and observed in-situ with the Atmosphere Explorer-E satellite. Data for three nights between October 29 and December 9, 1981, are presented. For this period, the meridional wind is observed to be northward after sunset and to turn south before midnight; the velocities often exceed 100 m/sec. After midnight, its direction is seen to reverse to northward for one to two hours. The reversal after midnight is recurrent and propagates from the equator, as predicted on the basis of previous meridional airglow intensity measurements.

  2. Model-based phase-shifting interferometer

    NASA Astrophysics Data System (ADS)

    Liu, Dong; Zhang, Lei; Shi, Tu; Yang, Yongying; Chong, Shiyao; Miao, Liang; Huang, Wei; Shen, Yibing; Bai, Jian

    2015-10-01

    A model-based phase-shifting interferometer (MPI) is developed, in which a novel calculation technique is proposed instead of the traditional complicated system structure, to achieve versatile, high precision and quantitative surface tests. In the MPI, the partial null lens (PNL) is employed to implement the non-null test. With some alternative PNLs, similar as the transmission spheres in ZYGO interferometers, the MPI provides a flexible test for general spherical and aspherical surfaces. Based on modern computer modeling technique, a reverse iterative optimizing construction (ROR) method is employed for the retrace error correction of non-null test, as well as figure error reconstruction. A self-compiled ray-tracing program is set up for the accurate system modeling and reverse ray tracing. The surface figure error then can be easily extracted from the wavefront data in forms of Zernike polynomials by the ROR method. Experiments of the spherical and aspherical tests are presented to validate the flexibility and accuracy. The test results are compared with those of Zygo interferometer (null tests), which demonstrates the high accuracy of the MPI. With such accuracy and flexibility, the MPI would possess large potential in modern optical shop testing.

  3. MIKES’ primary phase stepping gauge block interferometer

    NASA Astrophysics Data System (ADS)

    Byman, V.; Lassila, A.

    2015-08-01

    MIKES’ modernized phase stepping interferometer for gauge block calibration (PSIGB) will be described. The instrument is based on the well-regarded NPL-TESA gauge block interferometer from 1994. The decision to upgrade the instrument resulted from several components, such as the PC and charge-coupled device (CCD) camera, having reached the end of their lifetime. In this paper modernized components, measurement method and analysis will be explained. The lasers are coupled to the instrument using single mode fiber. The instrument uses phase stepping generated by an added optical window on a controllable rotatory table in the reference arm with a recently developed nine-position phase stepping algorithm. Unwrapping is done with a robust path following algorithm. Procedures for adjusting the interferometer are explained. Determination and elimination of wavefront error, coherent noise and analysis of their influence on the results is described. Flatness and variation in length are also important parameters of gauge blocks to be characterized, and the corresponding analysis method is clarified. Uncertainty analysis for the central length, flatness and variation in length is also described. The results are compared against those of the old hardware and software. The standard uncertainty for central length measurement is u = [(9.5 nm)2 + (121 × 10-9 L)2]½, where L is measured length.

  4. Thermal Dephasing in the Laughlin Quasiparticle Interferometer

    NASA Astrophysics Data System (ADS)

    Camino, F. E.; Zhou, Wei; Goldman, V. J.

    2006-03-01

    We report experiments on thermal dephasing of the Aharonov-Bohm oscillations in the novel Laughlin quasiparticle (LQP) interferometer, [1] where quasiparticles of the 1/3 FQH fluid execute a closed path around an island of the 2/5 fluid. In the 10.2 <=T <=141 mK temperature range, qualitatively, the experimental results follow a thermal dephasing dependence expected for an electron interferometer, and show clear distinction from the activated behavior observed in resonant tunneling and Coulomb blockade devices, both in the chiral Luttinger liquid (χLL) and the Fermi liquid regimes. The data fit very well the χLL dependence predicted for a g=1/3 two point-contact LQP interferometer. [2] The fit yields a value of the chiral edge excitation velocity, u=1.4x10^4 m/s obtained for the first time for a continuous FQH edge excitation spectrum. The small deviation from the zero-bias theory seen below 20 mK indicates yet unrecognized source of experimental decoherence, not included in theory. [1] F. E. Camino et al., Phys. Rev. B 72, 075342 (2005). [2] C. de C. Chamon et al., Phys. Rev. B 55, 2331 (1997).

  5. Orbiting stellar interferometer for astrometry and imaging

    NASA Technical Reports Server (NTRS)

    Colavita, M. M.; Shao, M.; Rayman, M. D.

    1993-01-01

    The orbiting stellar interferometer (OSI) is a concept for a first-generation space interferometer with astrometric and imaging goals. The OSI is a triple Michelson interferometer with articulating siderostats and optical delay lines. Two point designs for the instrument are described. The 18-m design uses an 18-m maximum baseline and aperture diameters of 40 cm; the targeted astrometric performance is a wide-field accuracy of 10 microarsec for 16-mag objects in 100 s of integration time and for 20-mag objects in 1 h. The instrument would also be capable of synthesis imaging with a resolution of 5 marcsec, which corresponds to the diffraction limit of the 18-m base line. The design uses a deployed structure, which would fold to fit into an Atlas IIAS shroud, for insertion into a 900-km sun-synchronous orbit. In addition to the 18-m point design, a 7-m point design that uses a shorter base line in order to simplify deployment is also discussed. OSI's high performance is made possible by utilizing laser metrology and controlled-optics technology.

  6. Hybrid photonic chip interferometer for embedded metrology

    NASA Astrophysics Data System (ADS)

    Kumar, P.; Martin, H.; Maxwell, G.; Jiang, X.

    2014-03-01

    Embedded metrology is the provision of metrology on the manufacturing platform, enabling measurement without the removal of the work piece. Providing closer integration of metrology upon the manufacturing platform can lead to the better control and increased throughput. In this work we present the development of a high precision hybrid optical chip interferometer metrology device. The complete metrology sensor system is structured into two parts; optical chip and optical probe. The hybrid optical chip interferometer is based on a silica-on-silicon etched integrated-optic motherboard containing waveguide structures and evanescent couplers. Upon the motherboard, electro-optic components such as photodiodes and a semiconductor gain block are mounted and bonded to provide the required functionality. The key structure in the device is a tunable laser module based upon an external-cavity diode laser (ECDL). Within the cavity is a multi-layer thin film filter which is rotated to select the longitudinal mode at which the laser operates. An optical probe, which uses a blazed diffracting grating and collimating objective lens, focuses light of different wavelengths laterally over the measurand. Incident laser light is then tuned in wavelength time to effectively sweep an `optical stylus' over the surface. Wavelength scanning and rapid phase shifting can then retrieve the path length change and thus the surface height. We give an overview of the overall design of the final hybrid photonic chip interferometer, constituent components, device integration and packaging as well as experimental test results from the current version now under evaluation.

  7. A Study of Imaging Interferometer Simulators

    NASA Technical Reports Server (NTRS)

    Allen, Ronald J.

    2002-01-01

    Several new space science mission concepts under development at NASA-GSFC for astronomy are intended to carry out synthetic imaging using Michelson interferometers or direct (Fizeau) imaging with sparse apertures. Examples of these mission concepts include the Stellar Imager (SI), the Space Infrared Interferometric Telescope (SPIRIT), the Submillimeter Probe of the Evolution of Cosmic Structure (SPECS), and the Fourier-Kelvin Stellar Interferometer (FKSI). We have been developing computer-based simulators for these missions. These simulators are aimed at providing a quantitative evaluation of the imaging capabilities of the mission by modelling the performance on different realistic targets in terms of sensitivity, angular resolution, and dynamic range. Both Fizeau and Michelson modes of operation can be considered. Our work is based on adapting a computer simulator called imSIM, which was initially written for the Space Interferometer Mission in order to simulate the imaging mode of new missions such as those listed. In a recent GSFC-funded study we have successfully written a preliminary version of a simulator SISIM for the Stellar Imager and carried out some preliminary studies with it. In a separately funded study we have also been applying these methods to SPECS/SPIRIT.

  8. Tunneling current through fractional quantum Hall interferometers

    NASA Astrophysics Data System (ADS)

    Smits, O.; Slingerland, J. K.; Simon, S. H.

    2014-01-01

    We calculate the tunneling current through a Fabry-Pérot interferometer in the fractional quantum Hall regime. Within linear response theory (weak tunneling but arbitrary source-drain voltage), we find a general expression for the current due to tunneling of quasiparticles in terms of Carlson's R function. Our result is valid for fractional quantum Hall states with an edge theory consisting of a charged channel and any number of neutral channels, with possibly different edge velocities and different chiralities. We analyze the case with a single neutral channel in detail, which applies for instance to the edge of the Moore-Read state. In addition, we consider an asymmetric interferometer with different edge lengths between the point contacts on opposite edges, and we study the behavior of the current as a function of varying edge length. Recent experiments attempted to measure the Aharanov-Bohm effect by changing the area inside the interferometer using a plunger gate. Theoretical analyses of these experiments have so far not taken into account the accompanying change in the edge lengths. We show that the tunneling current exhibits multiple oscillations as a function of this edge length, with frequencies proportional to the injected edge current and inversely proportional to the edge velocities. In particular, the edge velocities can be measured by looking at the Fourier spectrum of the edge current. We provide a numerical scheme to calculate and plot the R function, and include sample plots for a variety of edge states with parameter values, which are experimentally relevant.

  9. Spaceborne Radar Study

    DTIC Science & Technology

    1974-06-28

    If comm beam contact is lost, the instrumentation data are sent via the omnichannel transmitter on command of the ground station. There are six ways...comm’beam) at all times except when comm beam contact is lost. A two-way omnidirectional (backup) command link is provided for initial stabilization...via either the oomm beam or the omnichannel . Satellite instrumentation data are sent to the ground station following every radar signal transmission

  10. Shuttle imaging radar experiment

    USGS Publications Warehouse

    Elachi, C.; Brown, W.E.; Cimino, J.B.; Dixon, T.; Evans, D.L.; Ford, J.P.; Saunders, R.S.; Breed, C.; Masursky, H.; McCauley, J.F.; Schaber, G.; Dellwig, L.; England, A.; MacDonald, H.; Martin-Kaye, P.; Sabins, F.

    1982-01-01

    The shuttle imaging radar (SIR-A) acquired images of a variety of the earth's geologic areas covering about 10 million square kilometers. Structural and geomorphic features such as faults, folds, outcrops, and dunes are clearly visible in both tropical and arid regions. The combination of SIR-A and Seasat images provides additional information about the surface physical properties: topography and roughness. Ocean features were also observed, including large internal waves in the Andaman Sea. Copyright ?? 1982 AAAS.

  11. Weather Radar Studies.

    DTIC Science & Technology

    2014-09-26

    and Doppler weather radar data from the National Center for Atmospheric Research JAWS program and the National .Severe Storms Laboratory, are being...Atmospheric Research JAWS program and the National Severe Storms Laboratory, are being analyzed to develop low-altitude wind-shear detection algorithms...pictures, and dusted for fingerprints. The wind sensors, rain gauge, and antenna were destroyed but the DCP, solar panel, and other site components

  12. The Radar Roadmap

    DTIC Science & Technology

    2013-01-01

    LIMITATION OF ABSTRACT Same as Report ( SAR ) 18. NUMBER OF PAGES 25 19a. NAME OF RESPONSIBLE PERSON a. REPORT unclassified b. ABSTRACT unclassified c...ABSTRACT Same as Report ( SAR ) 18. NUMBER OF PAGES 25 19a. NAME OF RESPONSIBLE PERSON a. REPORT unclassified b. ABSTRACT unclassified c. THIS PAGE...object bistatic radars. The former allows high resolution without the use of pulse compression techniques and the latter promises cheaper systems by

  13. Imaging synthetic aperture radar

    DOEpatents

    Burns, Bryan L.; Cordaro, J. Thomas

    1997-01-01

    A linear-FM SAR imaging radar method and apparatus to produce a real-time image by first arranging the returned signals into a plurality of subaperture arrays, the columns of each subaperture array having samples of dechirped baseband pulses, and further including a processing of each subaperture array to obtain coarse-resolution in azimuth, then fine-resolution in range, and lastly, to combine the processed subapertures to obtain the final fine-resolution in azimuth. Greater efficiency is achieved because both the transmitted signal and a local oscillator signal mixed with the returned signal can be varied on a pulse-to-pulse basis as a function of radar motion. Moreover, a novel circuit can adjust the sampling location and the A/D sample rate of the combined dechirped baseband signal which greatly reduces processing time and hardware. The processing steps include implementing a window function, stabilizing either a central reference point and/or all other points of a subaperture with respect to doppler frequency and/or range as a function of radar motion, sorting and compressing the signals using a standard fourier transforms. The stabilization of each processing part is accomplished with vector multiplication using waveforms generated as a function of radar motion wherein these waveforms may be synthesized in integrated circuits. Stabilization of range migration as a function of doppler frequency by simple vector multiplication is a particularly useful feature of the invention; as is stabilization of azimuth migration by correcting for spatially varying phase errors prior to the application of an autofocus process.

  14. Goldstone solar system radar

    NASA Technical Reports Server (NTRS)

    Jurgens, Raymond F.

    1991-01-01

    Caltech/Jet Propulsion Laboratory (JPL) radar astronomers made use of the Very Large Array (VLA) at Socorro, NM, during February 1990, to receive radio echoes from the planet Venus. The transmitter was the 70 meter antenna at the Goldstone complex northwest of Barstow, CA. These observations contain new information about the roughness of Venus at cm to decimeter scales and are complementary to information being obtained by the Magellan spacecraft. Asteroid observations are also discussed.

  15. Cognitive Nonlinear Radar

    DTIC Science & Technology

    2013-01-01

    Devices and Method for Detecting Emplacement of Improvised Explosive Devices, U. S. Patent 7,680,599, Mar. 16, 2010. 11. Steele, D.; Rotondo, F.; Houck...Patent 7,987,068, Jul. 26, 2011. 9 14. Keller, W. Active Improvised Explosive Device (IED) Electronic Signature Detection , U. S. Patent...operate without interfering with each other. The CNR uses a narrowband, nonlinear radar target detection methodology. This methodology has the advantage

  16. Weather Radar Studies.

    DTIC Science & Technology

    1985-03-31

    National Center for Atmospheric Research JAWS program and the National Severe Storms Laboratory are being analyzed to develop low-altitude wind shear...public through low-altitude wind shear aviation weather products the National Technical Information Service, NEXR I turbulence., Springfield, VA 22161. 19...were analyzed preliminarily to determine wind shear characteristics in the Memphis area. Doppler weather radar data from the National Center for

  17. Rapid raw data simulation for fixed-receiver bistatic interferometric synthetic aperture radar

    NASA Astrophysics Data System (ADS)

    Yan, Feifei; Chang, Wenge; Li, Xiangyang

    2016-07-01

    Raw data simulation of synthetic aperture radar (SAR) is useful for system designing, mission planning, and testing of imaging algorithms. According to the two-dimensional (2-D) frequency spectrum of the fixed-receiver bistatic SAR system, a rapid raw data simulation approach is proposed. With the combination of 2-D inverse Stolt transform in the 2-D frequency domain and phase compensation in the range-Doppler frequency domain, our approach can significantly reduce the simulation time. Therefore, simulations of extended scenes can be performed much more easily. Moreover, the proposed algorithm offers high accuracy of phase distribution, therefore, it can be used for single-pass fixed-receiver bistatic interferometric usage. The proposal is verified by extensive simulations of point targets and extended scene, in which the results indicate the feasibility as well as the effectiveness of our approach. In the end, the accuracy of phase distribution of the proposed algorithm is further examined with simulations of synthetic aperture radar interferometry.

  18. Comet radar explorer

    NASA Astrophysics Data System (ADS)

    Farnham, Tony; Asphaug, Erik; Barucci, Antonella; Belton, Mike; Bockelee-Morvan, Dominique; Brownlee, Donald; Capria, Maria Teresa; Carter, Lynn; Chesley, Steve; Farnham, Tony; Gaskell, Robert; Gim, Young; Heggy, Essam; Herique, Alain; Klaasen, Ken; Kofman, Wlodek; Kreslavsky, Misha; Lisse, Casey; Orosei, Roberto; Plaut, Jeff; Scheeres, Dan

    The Comet Radar Explorer (CORE) is designed to perform a comprehensive and detailed exploration of the interior, surface, and inner coma structures of a scientifically impor-tant Jupiter family comet. These structures will be used to investigate the origins of cometary nuclei, their physical and geological evolution, and the mechanisms driving their spectacular activity. CORE is a high heritage spacecraft, injected by solar electric propulsion into orbit around a comet. It is capable of coherent deep radar imaging at decameter wavelengths, high resolution stereo color imaging, and near-IR imaging spectroscopy. Its primary objective is to obtain a high-resolution map of the interior structure of a comet nucleus at a resolution of ¿100 elements across the diameter. This structure shall be related to the surface geology and morphology, and to the structural details of the coma proximal to the nucleus. This is an ideal complement to the science from recent comet missions, providing insight into how comets work. Knowing the structure of the interior of a comet-what's inside-and how cometary activity works, is required before we can understand the requirements for a cryogenic sample return mission. But more than that, CORE is fundamental to understanding the origin of comets and their evolution in time. The mission is made feasible at low cost by the use of now-standard MARSIS-SHARAD reflec-tion radar imaging hardware and data processing, together with proven flight heritage of solar electric propulsion. Radar flight heritage has been demonstrated by the MARSIS radar on Mars Express (Picardi et al., Science 2005; Plaut et al., Science 2007), the SHARAD radar onboard the Mars Reconnaissance Orbiter (Seu et al., JGR 2007), and the LRS radar onboard Kaguya (Ono et al, EPS 2007). These instruments have discovered detailed subsurface structure to depths of several kilometers in a variety of terrains on Mars and the Moon. A reflection radar deployed in orbit about a comet

  19. Radar clutter classification

    NASA Astrophysics Data System (ADS)

    Stehwien, Wolfgang

    1989-11-01

    The problem of classifying radar clutter as found on air traffic control radar systems is studied. An algorithm based on Bayes decision theory and the parametric maximum a posteriori probability classifier is developed to perform this classification automatically. This classifier employs a quadratic discriminant function and is optimum for feature vectors that are distributed according to the multivariate normal density. Separable clutter classes are most likely to arise from the analysis of the Doppler spectrum. Specifically, a feature set based on the complex reflection coefficients of the lattice prediction error filter is proposed. The classifier is tested using data recorded from L-band air traffic control radars. The Doppler spectra of these data are examined; the properties of the feature set computed using these data are studied in terms of both the marginal and multivariate statistics. Several strategies involving different numbers of features, class assignments, and data set pretesting according to Doppler frequency and signal to noise ratio were evaluated before settling on a workable algorithm. Final results are presented in terms of experimental misclassification rates and simulated and classified plane position indicator displays.

  20. Radar gun hazards

    SciTech Connect

    Not Available

    1991-12-20

    Radar guns - hand-held units used by the law to nail speeders - have been in use since the early '60s. Now they've been accused of causing cancer. Police officers in several states have so far filed eight suits against the manufacturer, claiming that they have contracted rare forms of cancer, such as of the eyelid and the testicle, from frequent proximity to the devices. Spurred by concerns expressed by police groups, researchers at the Rochester Institute of Technology are conducting what they believe to be the first research of its kind in the nation. Last month psychologist John Violanti, an expert in policy psychology and health, sent out a one-page survey to 6,000 active and retired police officers in New York State, asking them about their health and their use of radar guns. Violanti says melanoma, leukemia, and lymph node cancer may be linked to these as well as other electromagnetic devices. The Food and Drug Administration earlier this year issued a warning about radar guns, telling users not to operate them closer than 6 inches from the body. But this may not be a sufficient safeguard since the instruments can give off crisscrossing wave emissions within a police vehicle. The survey will be used to help determine if it would be safer to mount the guns, which are currently either hand-held or mounted on dashboards, outside troopers' cars.

  1. Nordic Snow Radar Experiment

    NASA Astrophysics Data System (ADS)

    Lemmetyinen, Juha; Kontu, Anna; Pulliainen, Jouni; Vehviläinen, Juho; Rautiainen, Kimmo; Wiesmann, Andreas; Mätzler, Christian; Werner, Charles; Rott, Helmut; Nagler, Thomas; Schneebeli, Martin; Proksch, Martin; Schüttemeyer, Dirk; Kern, Michael; Davidson, Malcolm W. J.

    2016-09-01

    The objective of the Nordic Snow Radar Experiment (NoSREx) campaign was to provide a continuous time series of active and passive microwave observations of snow cover at a representative location of the Arctic boreal forest area, covering a whole winter season. The activity was a part of Phase A studies for the ESA Earth Explorer 7 candidate mission CoReH2O (Cold Regions Hydrology High-resolution Observatory). The NoSREx campaign, conducted at the Finnish Meteorological Institute Arctic Research Centre (FMI-ARC) in Sodankylä, Finland, hosted a frequency scanning scatterometer operating at frequencies from X- to Ku-band. The radar observations were complemented by a microwave dual-polarization radiometer system operating from X- to W-bands. In situ measurements consisted of manual snow pit measurements at the main test site as well as extensive automated measurements on snow, ground and meteorological parameters. This study provides a summary of the obtained data, detailing measurement protocols for each microwave instrument and in situ reference data. A first analysis of the microwave signatures against snow parameters is given, also comparing observed radar backscattering and microwave emission to predictions of an active/passive forward model. All data, including the raw data observations, are available for research purposes through the European Space Agency and the Finnish Meteorological Institute. A consolidated dataset of observations, comprising the key microwave and in situ observations, is provided through the ESA campaign data portal to enable easy access to the data.

  2. Seasonal Thickness Changes Revealed by Airborne Radar Interferometry, Pi-SAR2, at Two Glaciers Near Mt. Tsurugi, Japan

    NASA Astrophysics Data System (ADS)

    Furuya, M.; Fukui, K.; Kojima, S.; Matsuoka, T.

    2015-12-01

    Based on ice radar and high-preicision GPS measurements, Fukui and Iida (2012) have reported the presence of "glaciers" near Mt. Tsurugi, central Japan, which had been previously regarded as perenial snowy gorges. While their discovery was brought out by the modern geodetic techniques, there used to be a wrong idea that the equilibrium line altitude in central Japanese Alps is about 4000 meter, causing the actual glaciers to be overlooked; the elevation of Mt Tsurugi is 2999 meter. The presence of glaciers in central Japan is due to the very high seasonal accmulation; the snow fall in the mountainous regions can reach several tens of meters or more. There are, however, few snow-depth measurement data due to the logistic problems. The equilibrium line altitude also remains uncertain. We have performed airborne synthetic aperture radar (SAR) measurements near the two glaciers in August, October 2013, August 2014, and March 2015. The Pi-SAR2 system used in this study consists of X-band SAR antennas, and allows us to perform single-pass interferometry and full polarimetry with the maximum spatial resolution of 0.3 m. Taking advantage of the single-pass interferometry, we have generated digital elevation models (DEM) at each measurement epoch to derive the temporal changes in the thickness by differecing the DEMs of multiple epochs. Snow melt season starts in May at the analyzed area, and the first snow fall usually occurs in late October. As such, the minimum thickness is expected in October, when the glacier ice appears on the surface. Preliminary analyses indicate that the differences between August and October 2013 reaches ~10 to 20 meters with errors of 5-10 meters.

  3. High-resolution instrumentation radar

    NASA Astrophysics Data System (ADS)

    Dydbal, Robert B.; Hurlbut, Keith H.; Mori, Tsutomu T.

    1987-03-01

    An instrumentation radar that uses a chirp waveform to achieve high-range resolution is described. High-range-resolution instrumentation radars evaluate the target response to operational waveforms used in high-performance radars and/or obtain a display of the individual target scattering mechanisms to better understand the scattering process. This particular radar was efficiently constructed from a combination of commercially available components and in-house fabricated circuitry. This instrumentation radar operates at X-band and achieves a 4.9-in-range resolution. A key feature of the radar is the combination of amplitude weighting with a high degree of waveform fidelity to achieve a very good range sidelobe performance. This range sidelobe performance is important to avoid masking lower level target returns in the range sidelobes of higher target returns.

  4. Radar-aeolian roughness project

    NASA Technical Reports Server (NTRS)

    Greeley, Ronald; Dobrovolskis, A.; Gaddis, L.; Iversen, J. D.; Lancaster, N.; Leach, Rodman N.; Rasnussen, K.; Saunders, S.; Vanzyl, J.; Wall, S.

    1991-01-01

    The objective is to establish an empirical relationship between measurements of radar, aeolian, and surface roughness on a variety of natural surfaces and to understand the underlying physical causes. This relationship will form the basis for developing a predictive equation to derive aeolian roughness from radar backscatter. Results are given from investigations carried out in 1989 on the principal elements of the project, with separate sections on field studies, radar data analysis, laboratory simulations, and development of theory for planetary applications.

  5. Radar studies of bird migration

    NASA Technical Reports Server (NTRS)

    Williams, T. C.; Williams, J. M.

    1974-01-01

    Observations of bird migration with NASA radars were made at Wallops Island, Va. Simultaneous observations were made at a number of radar sites in the North Atlantic Ocean in an effort to discover what happened to those birds that were observed leaving the coast of North America headed toward Bermuda, the Caribbean and South America. Transatlantic migration, utilizing observations from a large number of radars is discussed. Detailed studies of bird movements at Wallops Island are presented.

  6. Radar Studies of Aviation Hazards

    DTIC Science & Technology

    1994-05-31

    4. TITLE AND SURTITLE S. FUNDING NUMBERS RADAR STUDIES OF AVIATION HAZARDS F1 9628-93- C -0054 _____________ __PE63707F 6. AUTHOR(S) PR278 1...foilowing processing steps have been adopted: a. acquire single scan radar data, b. distinguish individual storms, c . eliminate spurious data for...occurred only with radar reflectivities above 40 dBZ at the -10° C level and cloud tops above the -200C level. Lightning occurred only when tops extended

  7. The University of Florida LISA interferometer simulator

    NASA Astrophysics Data System (ADS)

    Mueller, Guido; Hochman, Steven; Mitryk, Shawn; Sanjuan Munoz, Jose; Preston, Alix; Sweeney, Dylan; Yu, Yinan; Tanner, David B.; Mueller, Guido

    Interferometric gravitational wave detectors such as LISA are built around two major subsys-tems. Gravitational reference sensors (GRS) consist of several freely-falling proof masses which follow variations in space time caused by passing gravitational waves. Spurious accelerations of the proof masses caused by technical or environmental forces have to be below the fN/rtHz level in the frequency band of interest. Interferometer measurement systems (IMS) measure the changes in the distances between the proof masses with sufficient sensitivity. The GRS-system for LISA has been developed over the last ten years and will be tested in a dedicated test mission, the LISA Test Package (LTP), scheduled for launch in 2012. The IMS of LISA is one of the most dynamic and longest interferometers ever envisioned. It consists of many subsystems which depend on the long light-travel times, the changes in the light-travel times and the induced Doppler shifts. The signals of the IMS are beat tones taken between vari-ous lasers at various locations on the three spacecraft. The phase evolution of each signal is measured against on-board clocks, after which linear combinations between appropriately time-shifted signals are formed to cancel about 10 orders of magnitude of laser frequency noise and thereby reach LISA sensitivity. Achieving 10 orders of magnitude of common mode rejection is already a daunting task for a small static interferometer in an optical laboratory. LISA is a very large and highly dynamic interferometer with constantly changing arms which for exam-ple requires to adapt permanently the noise cancelling linear combinations to the current arm lengths and spacecraft velocities while continuously monitoring the relative noise between the three independent on-board clocks. The University of Florida LISA Interferometer Simulator (UFLIS) is a hardware-in-the-loop simulator which includes multiple lasers, LISA-like signal travel-times and LISA-like Doppler shifts. UFLIS

  8. Development of stable monolithic wide-field Michelson interferometers

    NASA Astrophysics Data System (ADS)

    Wan, Xiaoke; Ge, Jian; Chen, Zhiping

    2011-07-01

    Bulk wide-field Michelson interferometers are very useful for high precision applications in remote sensing and astronomy. A stable monolithic Michelson interferometer is a key element in high precision radial velocity (RV) measurements for extrasolar planets searching and studies. Thermal stress analysis shows that matching coefficients of thermal expansion (CTEs) is a critical requirement for ensuring interferometer stability. This requirement leads to a novel design using BK7 and LAK7 materials, such that the monolithic interferometer is free from thermal distortion. The processes of design, fabrication, and testing of interferometers are described in detail. In performance evaluations, the field angle is typically 23.8° and thermal sensitivity is typically -2.6×10-6/° C near 550nm, which corresponds to ˜800m/s/°C in the RV scale. Low-cost interferometer products have been commissioned in multiple RV instruments, and they are producing high stability performance over long term operations.

  9. Refractometric sensor based on all-fiber coaxial Michelson interferometers

    NASA Astrophysics Data System (ADS)

    Barrios, Paola; Sáez-Rodríguez, David; Rodríguez, Amparo; Cruz, José L.; Díez, Antonio; Andrés, Miguel V.

    2009-05-01

    All-fiber coaxial Michelson interferometers are compact and very stable interferometers that can be dipped directly into water solutions for chemical and biological sensing. The sensitivity of the cladding mode to the surrounding medium can be exploited to use the interferometer as a compact fiber refractometer. Several interferometers have been fabricated and characterized as glucose sensors. A first series of devices were designed to work at 1550 nm, while a second series was prepared to work at 850 nm. Thus, the second series of interferometers enables the use of compact, robust and low cost optical spectrum analyzers. In our present experiments, the length of the fiber that forms the interferometer was within the range 1-10 cm. When the shift of the spectrum maxima were measured as a function of the glucose concentration, a slope of 350 pm/% was achieved. The use of the 850 nm sensor heads as a portable sensor system to monitor sewage treatment plants is shown.

  10. Development of stable monolithic wide-field Michelson interferometers.

    PubMed

    Wan, Xiaoke; Ge, Jian; Chen, Zhiping

    2011-07-20

    Bulk wide-field Michelson interferometers are very useful for high precision applications in remote sensing and astronomy. A stable monolithic Michelson interferometer is a key element in high precision radial velocity (RV) measurements for extrasolar planets searching and studies. Thermal stress analysis shows that matching coefficients of thermal expansion (CTEs) is a critical requirement for ensuring interferometer stability. This requirement leads to a novel design using BK7 and LAK7 materials, such that the monolithic interferometer is free from thermal distortion. The processes of design, fabrication, and testing of interferometers are described in detail. In performance evaluations, the field angle is typically 23.8° and thermal sensitivity is typically -2.6×10(-6)/°C near 550 nm, which corresponds to ∼800 m/s/°C in the RV scale. Low-cost interferometer products have been commissioned in multiple RV instruments, and they are producing high stability performance over long term operations.

  11. Radar Image, Hokkaido, Japan

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The southeast part of the island of Hokkaido, Japan, is an area dominated by volcanoes and volcanic caldera. The active Usu Volcano is at the lower right edge of the circular Lake Toya-Ko and near the center of the image. The prominent cone above and to the left of the lake is Yotei Volcano with its summit crater. The city of Sapporo lies at the base of the mountains at the top of the image and the town of Yoichi -- the hometown of SRTM astronaut Mamoru Mohri -- is at the upper left edge. The bay of Uchiura-Wan takes up the lower center of the image. In this image, color represents elevation, from blue at the lowest elevations to white at the highest. The radar image has been overlaid to provide more details of the terrain. Due to a processing problem, an island in the center of this crater lake is missing and will be properly placed when further SRTM swaths are processed. The horizontal banding in this image is a processing artifact that will be removed when the navigation information collected by SRTM is fully calibrated. This image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense (DoD), and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Earth Science Enterprise, Washington, DC. Size: 100 by 150 kilometers

  12. Reconfigurable L-Band Radar

    NASA Technical Reports Server (NTRS)

    Rincon, Rafael F.

    2008-01-01

    The reconfigurable L-Band radar is an ongoing development at NASA/GSFC that exploits the capability inherently in phased array radar systems with a state-of-the-art data acquisition and real-time processor in order to enable multi-mode measurement techniques in a single radar architecture. The development leverages on the L-Band Imaging Scatterometer, a radar system designed for the development and testing of new radar techniques; and the custom-built DBSAR processor, a highly reconfigurable, high speed data acquisition and processing system. The radar modes currently implemented include scatterometer, synthetic aperture radar, and altimetry; and plans to add new modes such as radiometry and bi-static GNSS signals are being formulated. This development is aimed at enhancing the radar remote sensing capabilities for airborne and spaceborne applications in support of Earth Science and planetary exploration This paper describes the design of the radar and processor systems, explains the operational modes, and discusses preliminary measurements and future plans.

  13. Python-ARM Radar Toolkit

    SciTech Connect

    Jonathan Helmus, Scott Collis

    2013-03-17

    The Python-ARM Radar Toolkit (Py-ART) is a collection of radar quality control and retrieval codes which all work on two unifying Python objects: the PyRadar and PyGrid objects. By building ingests to several popular radar formats and then abstracting the interface Py-ART greatly simplifies data processing over several other available utilities. In addition Py-ART makes use of Numpy arrays as its primary storage mechanism enabling use of existing and extensive community software tools.

  14. Terrestrial Planet Finder Interferometer: 2007-2008 Progress and Plans

    NASA Technical Reports Server (NTRS)

    Lawson, P. R.; Lay, O. P.; Martin, S. R.; Peters, R. D.; Gappinger, R. O.; Ksendzov, A.; Scharf, D. P.; Booth, A. J.; Beichman, C. A.; Serabyn, E.; Johnston, K. J.; Danchi, W. C.

    2008-01-01

    This paper provides an overview of technology development for the Terrestrial Planet Finder Interferometer (TPF-I). TPF-I is a mid-infrared space interferometer being designed with the capability of detecting Earth-like planets in the habitable zones around nearby stars. The overall technology roadmap is presented and progress with each of the testbeds is summarized. The current interferometer architecture, design trades, and the viability of possible reduced-scope mission concepts are also presented.

  15. Special topics in infrared interferometry. [Michelson interferometer development

    NASA Technical Reports Server (NTRS)

    Hanel, R. A.

    1985-01-01

    Topics in IR interferometry related to the development of a Michelson interferometer are treated. The selection and reading of the signal from the detector to the analog to digital converter is explained. The requirements for the Michelson interferometer advance speed are deduced. The effects of intensity modulation on the interferogram are discussed. Wavelength and intensity calibration of the interferometer are explained. Noise sources (Nyquist or Johnson noise, phonon noise), definitions of measuring methods of noise, and noise measurements are presented.

  16. Gravitational Wave Detection with Single-Laser Atom Interferometers

    NASA Technical Reports Server (NTRS)

    Yu, Nan; Tinto, Massimo

    2011-01-01

    A new design for a broadband detector of gravitational radiation relies on two atom interferometers separated by a distance L. In this scheme, only one arm and one laser are used for operating the two atom interferometers. The innovation here involves the fact that the atoms in the atom interferometers are not only considered as perfect test masses, but also as highly stable clocks. Atomic coherence is intrinsically stable, and can be many orders of magnitude more stable than a laser.

  17. Compact grating interferometer for producing photoresist gratings with incoherent light.

    PubMed

    Post, D; Patorski, K; Ning, P

    1987-03-15

    An achromatic interferometer was developed to produce 1200-lines/mm crossed-line photoresist gratings with a mercury arc light source. It is a compact reflection system of outstanding stability. Alignment procedures are described. The most stringent requirement, coplanar alignment of two folding gratings, was accomplished with the aid of a Twyman-Green interferometer. The grating interferometer produced crossed-line photoresist gratings with first-order diffraction efficiency exceeding 20%.

  18. Terrestrial Planet Finder Interferometer: Architecture, Mission Design, and Technology Development

    NASA Technical Reports Server (NTRS)

    Henry, Curt

    2004-01-01

    This slide presentation represents an overview progress report about the system design and technology development of two interferometer concepts studied for the Terrestrial Planet Finder (TPF) project. The two concepts are a structurally-connected interferometer (SCI) intended to fulfill minimum TPF science goals and a formation-flying interferometer (FFI) intended to fulfill full science goals. Described are major trades, analyses, and technology experiments completed. Near term plans are also described. This paper covers progress since August 2003

  19. A Comparison of Structurally Connected and Multiple Spacecraft Interferometers

    NASA Technical Reports Server (NTRS)

    Surka, Derek M.; Crawley, Edward F.

    1996-01-01

    Structurally connected and multiple spacecraft interferometers are compared in an attempt to establish the maximum baseline (referred to as the "cross-over baseline") for which it is preferable to operate a single-structure interferometer in space rather than an interferometer composed of numerous, smaller spacecraft. This comparison is made using the total launched mass of each configuration as the comparison metric. A framework of study within which structurally connected and multiple spacecraft interferometers can be compared is presented in block diagram form. This methodology is then applied to twenty-two different combinations of trade space parameters to investigate the effects of different orbits, orientations, truss materials, propellants, attitude control actuators, onboard disturbance sources, and performance requirements on the cross-over baseline. Rotating interferometers and the potential advantages of adding active structural control to the connected truss of the structurally connected interferometer are also examined. The minimum mass design of the structurally connected interferometer that meets all performance-requirements and satisfies all imposed constraints is determined as a function of baseline. This minimum mass design is then compared to the design of the multiple spacecraft interferometer. It is discovered that the design of the minimum mass structurally connected interferometer that meets all performance requirements and constraints in solar orbit is limited by the minimum allowable aspect ratio, areal density, and gage of the struts. In the formulation of the problem used in this study, there is no advantage to adding active structural control to the truss for interferometers in solar orbit. The cross-over baseline for missions of practical duration (ranging from one week to thirty years) in solar orbit is approximately 400 m for non-rotating interferometers and 650 m for rotating interferometers.

  20. Heterodyne Interferometer for Triggering Gas-Puff PRSs

    DTIC Science & Technology

    2007-11-02

    completion of the Phase I effort. They are: "* Implement a heterodyne interferometer in a Michelson format using fiber optic components. "* Interface the...of single-mode fiber cable. These fibers represent the two legs of a Michelson interferometer . One fiber is terminated in a reflector and is the...independently through the same fiber to the interferometer head. They are subject to identical stresses and, therefore, incur identical phase noise which cancels

  1. Modelling of interference pattern produced by Michelson interferometer

    NASA Astrophysics Data System (ADS)

    Glebov, Victor; Lashmanov, Oleg

    2016-04-01

    Using of Michelson interferometer is shown in the field of measurement of periodical displacements of the con-trolled object. The foundations of optical interferometry are presented. The features of Michelson interferometer are described. The mathematical model of interference pattern produced by Michelson interferometer is created. It takes in consideration such parameters as the angles at which the mirrors are located and the lengths of two optical paths.

  2. Analysis of a four-mirror-cavity enhanced Michelson interferometer.

    PubMed

    Thüring, André; Lück, Harald; Danzmann, Karsten

    2005-12-01

    We investigate the shot-noise-limited sensitivity of a four-mirror-cavity enhanced Michelson interferometer. The intention of this interferometer topology is the reduction of thermal lensing and the impact of the interferometers contrast although transmissive optics are used with high circulating powers. The analytical expressions describing the light fields and the frequency response are derived. Although the parameter space has 11 dimensions, a detailed analysis of the resonance feature gives boundary conditions allowing systematic parameter studies.

  3. An autocorrelator based on a Fabry-Perot interferometer.

    PubMed

    An, Jungkwuen; Pyun, Kyungsuk; Kwon, Ojoon; Kim, Dong Eon

    2013-01-14

    An autocorrelator based on a Fabry-Perot interferometer is proposed for ultrashort pulse measurement. Main features of this autocorrelator due to the superposition of multiple pulses were investigated experimentally and theoretically. It turns out that the signal from a Fabry-Perot interferometer can be used as an autocorrelator signal. This autocorrelator provides more compact setup with a much easier alignment than a conventional autocorrelator based on a Michelson interferometer.

  4. DC-offset-free homodyne interferometer and its nonlinearity compensation.

    PubMed

    Hu, Pengcheng; Zhu, Jinghao; Zhai, Xiaoyu; Tan, JiuBin

    2015-04-06

    This study presents an analysis of the cyclic nonlinearity in the homodyne interferometer starting from the interference principle. We present the design for an enhanced homodyne interferometer without DC offset, for which the nonlinearity model will not be influenced by the intensity of the measurement beam. Our experimental results show that the enhanced interferometer can suppress the nonlinearity to less than 0.5 nm with a system calibration involving gain adjustment and phase-correction methods.

  5. Laser diode feedback interferometer for stabilization and displacement measurements.

    PubMed

    Yoshino, T; Nara, M; Mnatzakanian, S; Lee, B S; Strand, T C

    1987-03-01

    Active laser diode interferometers in which the interference signal is fed back to the diode current are investigated for Twyman-Green and self-coupling interferometers. The Twyman-Green interferometer is stabilized with a stabilization factor of more than 100. By using the feedback signal of either type of interferometer, displacement is measured in a linear scale over a dynamic range of 8-9,microm with a precision of 10-60 nm. The feedback signal vs displacement shows hysteresis and multistable behavior, in accordance with theoretical results.

  6. Optical bistability and multistability in an active interferometer.

    PubMed

    Ohtsubo, J; Liu, Y

    1990-07-01

    Optoelectronic hybrid bistability and multistability in an active interferometer using a laser diode are demonstrated experimentally. The active laser-diode interferometer is composed of a Twyman-Green interferometer with an electronic feedback circuit. By feeding back the interferometer output together with an external light input through a detector to control thelaser-diode injection current, the optical bistable and multistable states of the output power from the laser diode are observed. Bistable operation does not require cutoff or saturation in the amplifier. The theoretical background of the phenomena is discussed.

  7. Trapped-atom interferometer with ultracold Sr atoms

    NASA Astrophysics Data System (ADS)

    Zhang, Xian; del Aguila, Ruben Pablo; Mazzoni, Tommaso; Poli, Nicola; Tino, Guglielmo M.

    2016-10-01

    We report on a trapped atom interferometer based on Bragg diffraction and Bloch oscillations with alkaline-earth-metal atoms. We use a Ramsey-Bordé Bragg interferometer with 88Sr atoms combined with Bloch oscillations to extend the interferometer time. Thanks to a long coherence time for Bloch oscillations of 88Sr atoms, we observed interference up to 1 s evolution time in the lattice. A detailed study of decoherence sources during the Bloch phase is also presented. While still limited in sensitivity by lattice lifetime and beam inhomogeneity this result opens the way to high contrast trapped interferometers with extended interrogation time.

  8. Two-path plasmonic interferometer with integrated detector

    DOEpatents

    Dyer, Gregory Conrad; Shaner, Eric A.; Aizin, Gregory

    2016-03-29

    An electrically tunable terahertz two-path plasmonic interferometer with an integrated detection element can down convert a terahertz field to a rectified DC signal. The integrated detector utilizes a resonant plasmonic homodyne mixing mechanism that measures the component of the plasma waves in-phase with an excitation field that functions as the local oscillator in the mixer. The plasmonic interferometer comprises two independently tuned electrical paths. The plasmonic interferometer enables a spectrometer-on-a-chip where the tuning of electrical path length plays an analogous role to that of physical path length in macroscopic Fourier transform interferometers.

  9. Millimeter Wave Cloud Radar (MMCR) Handbook

    SciTech Connect

    KB Widener; K Johnson

    2005-01-30

    The millimeter cloud radar (MMCR) systems probe the extent and composition of clouds at millimeter wavelengths. The MMCR is a zenith-pointing radar that operates at a frequency of 35 GHz. The main purpose of this radar is to determine cloud boundaries (e.g., cloud bottoms and tops). This radar will also report radar reflectivity (dBZ) of the atmosphere up to 20 km. The radar possesses a doppler capability that will allow the measurement of cloud constituent vertical velocities.

  10. Removing interfering clutter associated with radar pulses that an airborne radar receives from a radar transponder

    DOEpatents

    Ormesher, Richard C.; Axline, Robert M.

    2008-12-02

    Interfering clutter in radar pulses received by an airborne radar system from a radar transponder can be suppressed by developing a representation of the incoming echo-voltage time-series that permits the clutter associated with predetermined parts of the time-series to be estimated. These estimates can be used to estimate and suppress the clutter associated with other parts of the time-series.

  11. Planetary radar studies. [radar mapping of the Moon and radar signatures of lunar and Venus craters

    NASA Technical Reports Server (NTRS)

    Thompson, T. W.; Cutts, J. A.

    1981-01-01

    Progress made in studying the evolution of Venusian craters and the evolution of infrared and radar signatures of lunar crater interiors is reported. Comparison of radar images of craters on Venus and the Moon present evidence for a steady state Venus crater population. Successful observations at the Arecibo Observatory yielded good data on five nights when data for a mix of inner and limb areas were acquired. Lunar craters with radar bright ejects are discussed. An overview of infrared radar crater catalogs in the data base is included.

  12. Broadview Radar Altimetry Toolbox

    NASA Astrophysics Data System (ADS)

    Mondéjar, Albert; Benveniste, Jérôme; Naeije, Marc; Escolà, Roger; Moyano, Gorka; Roca, Mònica; Terra-Homem, Miguel; Friaças, Ana; Martinho, Fernando; Schrama, Ernst; Ambrózio, Américo; Restano, Marco

    2016-07-01

    The universal altimetry toolbox, BRAT (Broadview Radar Altimetry Toolbox) which can read all previous and current altimetry missions' data, incorporates now the capability to read the upcoming Sentinel-3 L1 and L2 products. ESA endeavoured to develop and supply this capability to support the users of the future Sentinel-3 SAR Altimetry Mission. BRAT is a collection of tools and tutorial documents designed to facilitate the processing of radar altimetry data. This project started in 2005 from the joint efforts of ESA (European Space Agency) and CNES (Centre National d'Études Spatiales), and it is freely available at http://earth.esa.int/brat. The tools enable users to interact with the most common altimetry data formats. The BratGUI is the front-end for the powerful command line tools that are part of the BRAT suite. BRAT can also be used in conjunction with MATLAB/IDL (via reading routines) or in C/C++/Fortran via a programming API, allowing the user to obtain desired data, bypassing the data-formatting hassle. BRAT can be used simply to visualise data quickly, or to translate the data into other formats such as NetCDF, ASCII text files, KML (Google Earth) and raster images (JPEG, PNG, etc.). Several kinds of computations can be done within BRAT involving combinations of data fields that the user can save for posterior reuse or using the already embedded formulas that include the standard oceanographic altimetry formulas. The Radar Altimeter Tutorial, that contains a strong introduction to altimetry, shows its applications in different fields such as Oceanography, Cryosphere, Geodesy, Hydrology among others. Included are also "use cases", with step-by-step examples, on how to use the toolbox in the different contexts. The Sentinel-3 SAR Altimetry Toolbox shall benefit from the current BRAT version. While developing the toolbox we will revamp of the Graphical User Interface and provide, among other enhancements, support for reading the upcoming S3 datasets and

  13. Broadview Radar Altimetry Toolbox

    NASA Astrophysics Data System (ADS)

    Escolà, Roger; Garcia-Mondejar, Albert; Moyano, Gorka; Roca, Mònica; Terra-Homem, Miguel; Friaças, Ana; Martinho, Fernando; Schrama, Ernst; Naeije, Marc; Ambrozio, Americo; Restano, Marco; Benveniste, Jérôme

    2016-04-01

    The universal altimetry toolbox, BRAT (Broadview Radar Altimetry Toolbox) which can read all previous and current altimetry missions' data, incorporates now the capability to read the upcoming Sentinel-3 L1 and L2 products. ESA endeavoured to develop and supply this capability to support the users of the future Sentinel-3 SAR Altimetry Mission. BRAT is a collection of tools and tutorial documents designed to facilitate the processing of radar altimetry data. This project started in 2005 from the joint efforts of ESA (European Space Agency) and CNES (Centre National d'Etudes Spatiales), and it is freely available at http://earth.esa.int/brat. The tools enable users to interact with the most common altimetry data formats. The BratGUI is the front-end for the powerful command line tools that are part of the BRAT suite. BRAT can also be used in conjunction with MATLAB/IDL (via reading routines) or in C/C++/Fortran via a programming API, allowing the user to obtain desired data, bypassing the data-formatting hassle. BRAT can be used simply to visualise data quickly, or to translate the data into other formats such as NetCDF, ASCII text files, KML (Google Earth) and raster images (JPEG, PNG, etc.). Several kinds of computations can be done within BRAT involving combinations of data fields that the user can save for posterior reuse or using the already embedded formulas that include the standard oceanographic altimetry formulas. The Radar Altimeter Tutorial, that contains a strong introduction to altimetry, shows its applications in different fields such as Oceanography, Cryosphere, Geodesy, Hydrology among others. Included are also "use cases", with step-by-step examples, on how to use the toolbox in the different contexts. The Sentinel-3 SAR Altimetry Toolbox shall benefit from the current BRAT version. While developing the toolbox we will revamp of the Graphical User Interface and provide, among other enhancements, support for reading the upcoming S3 datasets and

  14. Single pass Doppler positioning for Search and Rescue satellite missions

    NASA Technical Reports Server (NTRS)

    Schmid, P. E.; Vonbun, F. O.; Lynn, J. J.

    1976-01-01

    This paper describes the implementation of beacon location experiments involving the NASA Nimbus-6 and the Amateur Satellite Corporation (AMSAT) Oscar-6 and Oscar-7 spacecraft. The purpose of these experiments is to demonstrate the feasibility of determining the geographical location of a low power VHF 'distress beacon' via satellite. Doppler data collected during satellite passes is reduced in a mini-computer by means of a simple algorithm resulting in the simultaneous recovery of the unknown receiver coordinates and the unknown Doppler bias frequency. Results indicate point positioning to within a few kilometers - which is within the required accuracies for the positioning of downed aircraft for Search/Rescue missions.

  15. Hanford Single-Pass Reactor Fuel Storage Basin Demolition.

    PubMed

    Armstrong, Jason A.

    2003-02-01

    ABSTRACT The Environmental Restoration Contractor at the Hanford Site is tasked with removing auxiliary reactor structures and leaving the remaining concrete structure surrounding each reactor core. This is referred to as Interim Safe Storage. Part of placing the F Reactor into Interim Safe Storage is the demolition of the fuel storage basin, which was deactivated in 1970 by placing debris material into the basin prior to back filling with soil. Besides the debris material (wooden floor decking, handrails, and monorail pieces), the fuel storage basin contents included the possibility of spent nuclear fuel, fuel buckets, fuel spacers, process tubes, and tongs. Demolition of the fuel storage basin offered many unique radiological control challenges and innovative approaches to demolition. This paper describes how the total effective dose equivalent and contamination were controlled, how the use of a remote operated excavator was employed to remove high-dose-rate material, and how wireless technology was used to monitor changing radiological conditions.

  16. Hanford single-pass reactor fuel storage basin demolition.

    PubMed

    Armstrong, Jason A

    2003-02-01

    The Environmental Restoration Contractor at the Hanford Site is tasked with removing auxiliary reactor structures and leaving the remaining concrete structure surrounding each reactor core. This is referred to as Interim Safe Storage. Part of placing the F Reactor into Interim Safe Storage is the demolition of the fuel storage basin, which was deactivated in 1970 by placing debris material into the basin prior to back filling with soil. Besides the debris material (wooden floor decking, handrails, and monorail pieces), the fuel storage basin contents included the possibility of spent nuclear fuel, fuel buckets, fuel spacers, process tubes, and tongs. Demolition of the fuel storage basin offered many unique radiological control challenges and innovative approaches to demolition. This paper describes how the total effective dose equivalent and contamination were controlled, how the use of a remote operated excavator was employed to remove high-dose-rate material, and how wireless technology was used to monitor changing radiological conditions.

  17. Single-pass memory system evaluation for multiprogramming workloads

    NASA Technical Reports Server (NTRS)

    Conte, Thomas M.; Hwu, Wen-Mei W.

    1990-01-01

    Modern memory systems are composed of levels of cache memories, a virtual memory system, and a backing store. Varying more than a few design parameters and measuring the performance of such systems has traditionally be constrained by the high cost of simulation. Models of cache performance recently introduced reduce the cost simulation but at the expense of accuracy of performance prediction. Stack-based methods predict performance accurately using one pass over the trace for all cache sizes, but these techniques have been limited to fully-associative organizations. This paper presents a stack-based method of evaluating the performance of cache memories using a recurrence/conflict model for the miss ratio. Unlike previous work, the performance of realistic cache designs, such as direct-mapped caches, are predicted by the method. The method also includes a new approach to the problem of the effects of multiprogramming. This new technique separates the characteristics of the individual program from that of the workload. The recurrence/conflict method is shown to be practical, general, and powerful by comparing its performance to that of a popular traditional cache simulator. The authors expect that the availability of such a tool will have a large impact on future architectural studies of memory systems.

  18. Single Pass Collider Memo: Gradient Perturbations of the SLC arc

    SciTech Connect

    Weng, W. T.; Sands, M.

    2016-12-16

    As the beam passes through the arcs, the gradient it encounters at each magnet differs from the design value. This deviation may be in part random and in part systematic. In this note we make estimates of the effects to be expected from both kinds of errors.

  19. A Study of Single Pass Ion Effects at the ALS

    SciTech Connect

    Byrd, J.M.; Thomson, J.; Chao, A.W.; Heifets, S.; Minty, M.G.; Seeman, J.T.; Stupakov, G.V.; Zimmermann, F.; Raubenheimer, T.O.; /CERN

    2011-09-13

    We report the results of experiments on a 'fast beam-ion instability' at the Advanced Light Source (ALS). This ion instability, which can arise even when the ions are not trapped over multiple beam passages, will likely be important for many future accelerators. In our experiments, we filled the ALS storage ring with helium gas, raising the pressure approximately two orders of magnitude above the nominal pressure. With gaps in the bunch train large enough to avoid conventional (multi-turn) ion trapping, we observed a factor of 2-3 increase in the vertical beam size along with coherent beam oscillations which increased along the bunch train. Ion trapping has long been recognized as a potential limitation in electron storage rings. The ions, generated by beam-gas collisions, become trapped in the negative potential of the beam and accumulate over multiple beam passages. The trapped ions are then observed to cause a number of deleterious effects such as an increasing beam phase space, a broadening and shifting of the beam transverse oscillation frequencies (tunes), collective beam instabilities, and beam lifetime reductions. All of these effects are of concern for the next generation of accelerators, such as the B-factories or damping rings for future linear colliders, which will store high beam currents with closely spaced bunches and ultra-low beam emittances. One of the standard solutions used to prevent ion trapping is to include a gap in the bunch train which is long compared to the bunch spacing. In this case, the ions are first strongly-focused by the passing electron bunches and then over-focused in the gap. With a sufficiently large gap, the ions can be driven to large amplitudes where they form a diffuse halo and do not affect the beam. In this paper, we describe experiments that study a new regime of transient ion instabilities predicted to arise in future electron storage rings, and linacs with bunch trains. These future rings and linacs, which will be operated with higher beam currents, small transverse beam emittances, and long bunch trains, will use ion clearing gaps to prevent conventional ion trapping. But, while the ion clearing gap may suppress the conventional ion instabilities, it will not suppress a transient beam-ion instability where ions generated and trapped during the passage of a single train lead to a fast instability. While both conventional and transient ion instabilities have the same origin, namely ions produced by the beam, they have different manifestations and, more importantly, the new transient instability can arise even after the conventional ion instability is cured. This new instability is called the 'Fast Beam-Ion Instability' (FBII). In many future rings, the FBII is predicted to have very fast growth rates, much faster than the damping rates of existing and proposed transverse feedback systems, and thus is a potential limitation. To study the FBII, we performed experiments at the ALS, a 1.5 GeV electron storage ring. At the nominal ALS pressure of about 0.24 nTorr, the FBII is not evident. To study the instability, we intentionally added helium gas to the storage-ring vacuum system until the residual gas pressure was increased about 80 nTorr. This brought the predicted growth rate of the instability at least an order of magnitude above the growth rate of conventional multibunch instabilities driven by the RF cavities and above the damping rate of the transverse feedback system (TFB) in the ALS and, thereby, established conditions very similar to those in a future storage ring. We then filled the ring with a relatively short train of bunches, suppressing conventional ion instabilities. In the following, we will first briefly describe This paper describes the experiment and results in more detail.

  20. Single-Pass Memory System Evaluation for Multiprogramming Workloads

    DTIC Science & Technology

    1990-05-01

    compared against Dinero III, a I reliable public-domain cache simulator constructed by Mark Hill. These results are presented 3 in Table 2. rhe minutes of...depth. The worst slowdown was 3 12 I Table 2: Running time versus Dinero III. Time Average Recurrence/ Dinero III ratio Benchmark Conflict model (21,4,oo...21,4,0) RCM/ Dinero grep 1:38 0:21 0:20 4.8 tex 4:35 0:17 0:16 16 yacc 0:53 0:03 0:03 18 bv a factor of 18. However, given that the design space