WorldWideScience

Sample records for submillimeter heterodyne arrays

  1. A submillimeter VLBI array

    Energy Technology Data Exchange (ETDEWEB)

    Weintroub, Jonathan [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA (United States)], E-mail: jweintroub@cfa.harvard.edu

    2008-10-15

    A VLBI array operating at {lambda} 1.3 mm and 0.8 mm is being designed using existing submillimeter telescopes as ad-hoc stations. Initial three station {lambda} = 1.3 mm observations of SgrA* and other AGN have produced remarkable results, which are reported by Doeleman elsewhere in this proceedings. Future observations are planned with an enhanced array which has longer baselines, more stations, and greater sensitivity. At {lambda} = 0.8 mm and on the long baselines, the array will have about a 20 {mu}as angular resolution which equals the diameter of the event horizon of the massive black hole in SgrA*. Candidate single dish facilities include the Arizona Radio Observatory Submillimeter Telescope (SMT) in Arizona, the Caltech Submillimeter Observatory (CSO) and the James Clerk Maxwell telescope (JCMT) in Hawaii, the Large Millimeter Telescope (LMT) in Mexico, ASTE and APEX in Chile, and the IRAM 30 m in Spain; interferometers include the Submillimeter Array (SMA) in Hawaii, the Combined Array for Research in Millimeter-wave Astronomy (CARMA) in California, IRAM PdB Interferometer in France, and the Atacama Large Millimeter Array (ALMA) in Chile. I will discuss the techniques we have developed for phasing interferometric arrays to act as single VLBI station. A strategy for detection of short (10s) time-scale source variability using VLBI closure phase will be described.

  2. Next generation heterodyne array for JCMT

    Science.gov (United States)

    Chen, M.-T.; Dempsey, J.; Ho, P. T. P.; Friberg, P.; Bintley, D.; Walther, C.

    2016-07-01

    As part of the JCMT Future Instrumentation Project, the EAO looks to optimize the premier niche of the facility as the go-to telescope for fast, deep wide-field mapping of the universe at 345 GHz (850 um). The next generation heterodyne array for JCMT will be designed to provide deep ultra-fast mapping capabilities that takes advantage of the full field-of-view available to the telescope, and an array of 90 SIS mixers. This paper presents a preliminary design options and the critical science drivers for the project.

  3. Arrays of Bolometers for Far-infrared and Submillimeter Astronomy

    Science.gov (United States)

    Chuss, D. T.; Allen, C. A.; Babu, S.; Benford, D. J.; Dotson, J. L.; Dowell, C. D.; Jhabvala, M.; Harper, D. A.; Moseley, S. Harvey; Silverberg, R. F.; Staguhn, J. G.; Voellmer, G.; Wollack, E. J.

    We describe 12 x 32 arrays of semiconducting cryogenic bolometers designed for use in far-infrared and submillimeter cameras. These 12 x 32 arrays are constructed from 1 x 32 monolithic pop-up detectors developed at NASA Goddard Space Flight Center. The pop-up technology allows the construction of large arrays with high filling factors that provide efficient use of space in the focal planes of far-infrared and submillimeter astronomical instruments. This directly leads to a significant decrease in integration time. The prototype array is currently operating in the second generation Submillimeter High Angular Resolution Camera (SHARC II), a facility instrument in use at the Caltech Submillimeter Observatory (CSO). The elements of this array employ a bismuth absorber coating and quarter wave backshort to optimize the bolometer absorption for passbands centered at 350 and 450 microns. A second array is to be installed in the High-resolution Airborne Widebandwidth Camera (HAWC), a far-infrared imaging camera for the Stratospheric Observatory for Infrared Astronomy (SOFIA). This array has been completed and is now awaiting integration into the HAWC test cryostat. HAWC is scheduled for commissioning in 2005. The HAWC array employs titanium-gold absorbers and is optimized for uniform absorption from 40 to 300 microns to accommodate all four of its far-infrared passbands. We describe the details of the HAWC array construction including the mechanical design and electrical characterization of the constituent linear arrays.

  4. Two bolometer arrays for far-infrared and submillimeter astronomy

    Science.gov (United States)

    Silverberg, Robert F.; Allen, Christine A.; Babu, Sachidananda R.; Benford, Dominic J.; Chuss, David T.; Dotson, Jessie L.; Dowell, Charles D.; Harper, Doyle A.; Jhabvala, Murzy D.; Loewenstein, Robert F.; Moseley, S. H., Jr.; Staguhn, Johannes G.; Voellmer, George M.; Wollack, Edward J.

    2004-10-01

    We describe the development, construction, and testing of two 384 element arrays of ion-implanted semiconducting cryogenic bolometers designed for use in far-infrared and submillimeter cameras. These two dimensional arrays are assembled from a number of 32 element linear arrays of monolithic Pop-Up bolometer Detectors (PUD) developed at NASA/Goddard Space Flight Center. PUD technology allows the construction of large, high filling factor, arrays that make efficient use of available focal plane area in far-infrared and submillimeter astronomical instruments. Such arrays can be used to provide a significant increase in mapping speed over smaller arrays. A prototype array has been delivered and integrated into a ground-based camera, the Submillimeter High Angular Resolution Camera (SHARC II), a facility instrument at the Caltech Submillimeter Observatory (CSO). A second array has recently been delivered for integration into the High-resolution Airborne Widebandwidth Camera (HAWC), a far-infrared imaging camera for the Stratospheric Observatory for Infrared Astronomy (SOFIA). HAWC is scheduled for commissioning in 2005.

  5. Alignment error analysis of detector array for spatial heterodyne spectrometer.

    Science.gov (United States)

    Jin, Wei; Chen, Di-Hu; Li, Zhi-Wei; Luo, Hai-Yan; Hong, Jin

    2017-12-10

    Spatial heterodyne spectroscopy (SHS) is a new spatial interference spectroscopy which can achieve high spectral resolution. The alignment error of the detector array can lead to a significant influence with the spectral resolution of a SHS system. Theoretical models for analyzing the alignment errors which are divided into three kinds are presented in this paper. Based on these models, the tolerance angle of these errors has been given, respectively. The result of simulation experiments shows that when the angle of slope error, tilt error, and rotation error are less than 1.21°, 1.21°, 0.066° respectively, the alignment reaches an acceptable level.

  6. Submillimeter Array reveals molecular complexity of dying stars

    Science.gov (United States)

    Tomasz

    2018-01-01

    The unique capabilities of the Submillimeter Array (SMA) have allowed unprecedented studies of cool evolved stars at submillimeter wavelengths. In particular, the SMA now offers the possibility to image multiple molecular transitions at once, owing to the 32-GHz wide instantaneous bandwidth of SWARM, the SMA’s new correlator. Molecular gas located far and very close to the photosphere of an asymptotic-giant branch (AGB) star, a red supergiant, or a pre-planetary nebula can now be examined in transitions observed simultaneously from a wide range of energy levels. This allows a very detailed quantitative investigation of physical and chemical conditions around these variable objects. Several imaging line surveys have been obtained with the SMA to reveal the beautiful complexity of these evolved systems. The surveys resulted in first submillimeter-wave identifications of molecules of prime astrophysical interest, e.g. of TiO, TiO2, and of rotational transitions at excited vibrational states of CO. An overview of recent SMA observations of cool evolved stars will be given with an emphasize on the interferometric line surveys. We will demonstrate their importance in unraveling the mass-loss phenomena, propagation of shocks in the circumstellar medium, and production of dust at elevated temperatures. The SMA studies of these molecular factories have a direct impact on our understanding of the chemical evolution of the Galaxy and stellar evolution at low and high masses.

  7. Superconducting Microwave Resonator Arrays for Submillimeter/Far-Infrared Imaging

    Science.gov (United States)

    Noroozian, Omid

    Superconducting microwave resonators have the potential to revolutionize submillimeter and far-infrared astronomy, and with it our understanding of the universe. The field of low-temperature detector technology has reached a point where extremely sensitive devices like transition-edge sensors are now capable of detecting radiation limited by the background noise of the universe. However, the size of these detector arrays are limited to only a few thousand pixels. This is because of the cost and complexity of fabricating large-scale arrays of these detectors that can reach up to 10 lithographic levels on chip, and the complicated SQUID-based multiplexing circuitry and wiring for readout of each detector. In order to make substantial progress, next-generation ground-based telescopes such as CCAT or future space telescopes require focal planes with large-scale detector arrays of 104--10 6 pixels. Arrays using microwave kinetic inductance detectors (MKID) are a potential solution. These arrays can be easily made with a single layer of superconducting metal film deposited on a silicon substrate and pattered using conventional optical lithography. Furthermore, MKIDs are inherently multiplexable in the frequency domain, allowing ˜ 10 3 detectors to be read out using a single coaxial transmission line and cryogenic amplifier, drastically reducing cost and complexity. An MKID uses the change in the microwave surface impedance of a superconducting thin-film microresonator to detect photons. Absorption of photons in the superconductor breaks Cooper pairs into quasiparticles, changing the complex surface impedance, which results in a perturbation of resonator frequency and quality factor. For excitation and readout, the resonator is weakly coupled to a transmission line. The complex amplitude of a microwave probe signal tuned on-resonance and transmitted on the feedline past the resonator is perturbed as photons are absorbed in the superconductor. The perturbation can be

  8. HARP : A submillimetre heterodyne array receiver operating on the James Clerk Maxwell Telescope

    NARCIS (Netherlands)

    Smith, H.; Buckle, J.; Hills, R.; Bell, G.; Richer, J.; Curtis, E.; Withington, S.; Leech, J.; Williamson, R.; Klapwijk, T.M.

    2008-01-01

    This paper describes the key design features and performance of HARP, an innovative heterodyne focal-plane array receiver designed and built to operate in the submillimetre on the James Clerk Maxwell Telescope (JCMT) in Hawaii. The 4x4 element array uses SIS detectors, and is the first

  9. Deciphering Debris Disk Structure with the Submillimeter Array

    Science.gov (United States)

    MacGregor, Meredith Ann

    2018-01-01

    More than 20% of nearby main sequence stars are surrounded by dusty disks continually replenished via the collisional erosion of planetesimals, larger bodies similar to asteroids and comets in our own Solar System. The material in these ‘debris disks’ is directly linked to the larger bodies such as planets in the system. As a result, the locations, morphologies, and physical properties of dust in these disks provide important probes of the processes of planet formation and subsequent dynamical evolution. Observations at millimeter wavelengths are especially critical to our understanding of these systems, since they are dominated by larger grains that do not travel far from their origin and therefore reliably trace the underlying planetesimal distribution. The Submillimeter Array (SMA) plays a key role in advancing our understanding of debris disks by providing sensitivity at the short baselines required to determine the structure of wide-field disks, such as the HR 8799 debris disk. Many of these wide-field disks are among the closest systems to us, and will serve as cornerstone templates for the interpretation of more distant, less accessible systems.

  10. Solar Observations with the Atacama Large Millimeter/submillimeter Array

    Science.gov (United States)

    Wedemeyer, Sven

    2015-08-01

    The interferometric Atacama Large Millimeter/submillimeter Array (ALMA) has already demonstrated its impressive capabilities by observing a large variety of targets ranging from protoplanetary disks to galactic nuclei. ALMA is also capable of observing the Sun and has been used for five solar test campaigns so far. The technically challenging solar observing modes are currently under development and regular observations are expected to begin in late 2016.ALMA consists of 66 antennas located in the Chilean Andes at an altitude of 5000 m and is a true leap forward in terms of spatial resolution at millimeter wavelengths. The resolution of reconstructed interferometric images of the Sun is anticipated to be close to what current optical solar telescopes can achieve. In combination with the high temporal and spectral resolution, these new capabilities open up new parameter spaces for solar millimeter observations.The solar radiation at wavelengths observed by ALMA originates from the chromosphere, where the height of the sampled layer increases with selected wavelength. The continuum intensity is linearly correlated to the local gas temperature in the probed layer, which makes ALMA essentially a linear thermometer. During flares, ALMA can detect additional non-thermal emission contributions. Measurements of the polarization state facilitate the valuable determination of the chromospheric magnetic field. In addition, spectrally resolved observations of radio recombination and molecular lines may yield great diagnostic potential, which has yet to be investigated and developed.Many different scientific applications for a large range of targets from quiet Sun to active regions and prominences are possible, ranging from ultra-high cadence wave studies to flare observations. ALMA, in particular in combination with other ground-based and space-borne instruments, will certainly lead to fascinating new findings, which will advance our understanding of the atmosphere of our Sun

  11. Optimizing end-to-end system performance for millimeter and submillimeter spectroscopy of protostars : wideband heterodyne receivers and sideband-deconvolution techniques for rapid molecular-line surveys

    Science.gov (United States)

    Sumner, Matthew Casey

    This thesis describes the construction, integration, and use of a new 230-GHz ultra-wideband heterodyne receiver, as well as the development and testing of a new sideband-deconvolution algorithm, both designed to enable rapid, sensitive molecular-line surveys. The 230-GHz receiver, known as Z-Rex, is the first of a new generation of wideband receivers to be installed at the Caltech Submillimeter Observatory (CSO). Intended as a proof-of-concept device, it boasts an ultra-wide IF output range of sim 6 - 18 GHz, offering as much as a twelvefold increase in the spectral coverage that can be achieved with a single LO setting. A similarly wideband IF system has been designed to couple this receiver to an array of WASP2 spectrometers, allowing the full bandwidth of the receiver to be observed at low resolution, ideal for extra-galactic redshift surveys. A separate IF system feeds a high-resolution 4-GHz AOS array frequently used for performing unbiased line surveys of galactic objects, particularly star-forming regions. The design and construction of the wideband IF system are presented, as is the work done to integrate the receiver and the high-resolution spectrometers into a working system. The receiver is currently installed at the CSO where it is available for astronomers' use. In addition to demonstrating wideband design principles, the receiver also serves as a testbed for a synthesizer-driven, active LO chain that is under consideration for future receiver designs. Several lessons have been learned, including the importance of driving the final amplifier of the LO chain into saturation and the absolute necessity of including a high-Q filter to remove spurious signals from the synthesizer output. The on-telescope performance of the synthesizer-driven LO chain is compared to that of the Gunn-oscillator units currently in use at the CSO. Although the frequency agility of the synthesized LO chain gives it a significant advantage for unbiased line surveys, the cleaner

  12. A deeply embedded young protoplanetary disk around L1489 IRS observed by the Submillimeter Array

    DEFF Research Database (Denmark)

    Brinch, C.; Crapsi, A.; Jørgensen, J. K.

    2007-01-01

    aim to identify whether an embedded Keplerian protoplanetary disk resides in the L1489 IRS system. Given the amount of envelope material still present, such a disk would respresent a very young example of a protoplanetary disk. Methods. Using the Submillimeter Array we have observed the HCO + J = 3......-2 line with a resolution of about 1". At this resolution a protoplanetary disk with a radius of a few hundred AUs should be detectable, if present. Radiative transfer tools are used to model the emission from both continuum and line data. Results. We find that these data are consistent with theoretical...

  13. THz Direct Detector and Heterodyne Receiver Arrays in Silicon Nanoscale Technologies

    Science.gov (United States)

    Grzyb, Janusz; Pfeiffer, Ullrich

    2015-10-01

    The main scope of this paper is to address various implementation aspects of THz detector arrays in the nanoscale silicon technologies operating at room temperatures. This includes the operation of single detectors, detectors operated in parallel (arrays), and arrays of detectors operated in a video-camera mode with an internal reset to support continuous-wave illumination without the need to synchronize the source with the camera (no lock-in receiver required). A systematic overview of the main advantages and limitations in using silicon technologies for THz applications is given. The on-chip antenna design challenges and co-design aspects with the active circuitry are thoroughly analyzed for broadband detector/receiver operation. A summary of the state-of-the-art arrays of broadband THz direct detectors based on two different operation principles is presented. The first is based on the non-quasistatic resistive mixing process in a MOSFET channel, whereas the other relies on the THz signal rectification by nonlinearity of the base-emitter junction in a high-speed SiGe heterojunction bipolar transistor (HBT). For the MOSFET detector arrays implemented in a 65 nm bulk CMOS technology, a state-of-the-art optical noise equivalent power (NEP) of 14 pW/ at 720 GHz was measured, whereas for the HBT detector arrays in a 0.25 μm SiGe process technology, an optical NEP of 47 pW/ at 700 GHz was found. Based on the implemented 1k-pixel CMOS camera with an average power consumption of 2.5 μW/pixel, various design aspects specific to video-mode operation are outlined and co-integration issues with the readout circuitry are analyzed. Furthermore, a single-chip 2 × 2 array of heterodyne receivers for multi-color active imaging in a 160-1000 GHz band is presented with a well-balanced NEP across the operation bandwidth ranging from 0.1 to 0.24 fW/Hz (44.1-47.8 dB single-sideband NF) and an instantaneous IF bandwidth of 10 GHz. In its present implementation, the receiver RF

  14. Silicon Micromachined Heterodyne Array Receiver at 1.9 THz Project

    Data.gov (United States)

    National Aeronautics and Space Administration — "We are proposing a new concept of integrated component development technology at submillimeter wavelengths that will dramatically simplify the fabrication,...

  15. Saturation effects in heterodyne detection with Geiger-mode InGaAs avalanche photodiode detector arrays.

    Science.gov (United States)

    Luu, Jane X; Jiang, Leaf A

    2006-06-01

    We report, to the best of our knowledge, the first demonstration of heterodyne detection of a glint target using an InGaAs avalanche photodiode detector (APD) array in the Geiger mode. Due to the finite number of pixels, all such photon-counting arrays necessarily suffer from saturation effects. At large photon fluxes, saturation of the APD degrades the Doppler frequency resolution and the signal-to-noise ratio (SNR). We derive analytical expressions for the Doppler resolution and SNR, taking saturation effects into account. The optimal local oscillator power can be obtained numerically from the SNR expression.

  16. Taiwanese antennas for the Sub-Millimeter Array: a progress report

    Science.gov (United States)

    Raffin, Phillippe A.; Liu, Ching-Tang; Cervera, Mathieu; Chang, Chi-Ling; Chen, Ming-Tang; Lee, Cheng-Ching; Lee, Typhoon; Lo, Kwok-Yung; Ma, Rwei-Ping; Martin, Robert N.; Martin-Cocher, Pierre; Ong, Ching-Long; Park, Yong-Sun; Tsai, Rong-Den; Wu, Enboa; Yang, Shun-Cheng; Yang, Tien-Szu

    2000-07-01

    The Academia Sinica, Institute for Astronomy and Astrophysics (ASIAA) is building two antennas to be added to the six antennas of the Sub-Millimeter Array (SMA) of the Smithsonian Astrophysical Observatory (SAO). The antennas have been designed at SAO and are currently under construction at Mauna Kea. ASIAA's two antennas are made in Taiwan from parts manufactured locally and imported from Europe and from the USA. This report will focus on the manufacturing and testing of 2 major components: the alidade and the reflector. We will emphasize the work done on the composite parts used in the 6- meter reflectors, namely the carbon fiber tubes for the backup structure, the carbon fiber legs of the quadrupod and the composite central hub. We will discuss the modal testing and pointing tests of the antennas. Finally this report will show how the Taiwanese industry was able to respond to the high manufacturing standards required to build sub-millimeter antennas. The design and manufacturing capabilities of the Aeronautical Research Laboratories and China Shipbuilding Corporation have made possible the construction of the telescopes in Taiwan.

  17. The Atacama Large Millimeter/submillimeter Array - from Early Science to Full Operations.

    Science.gov (United States)

    Remijan, Anthony

    2017-06-01

    The Atacama Large Millimeter/Submillimeter Array (ALMA) is now entering its 6th cycle of scientific observations. Starting with Cycle 3, science observations were no longer considered "Early Science" or "best efforts". Cycle 5 is now the third cycle of "steady state" observations and Cycle 7 is advertised to begin ALMA "full science" operations. ALMA Full Science Operations will include all the capabilities that were agreed upon by the international consortium after the ALMA re-baselining effort. In this talk, I will detail the upcoming ALMA Cycle 5 observing capabilities, describe the process of selecting new observing modes for upcoming cycles and provide an update on the status of the ALMA Full Science capabilities.

  18. A sub-millimeter resolution PET detector module using a multi-pixel photon counter array

    Science.gov (United States)

    Song, Tae Yong; Wu, Heyu; Komarov, Sergey; Siegel, Stefan B.; Tai, Yuan-Chuan

    2010-05-01

    A PET block detector module using an array of sub-millimeter lutetium oxyorthosilicate (LSO) crystals read out by an array of surface-mount, semiconductor photosensors has been developed. The detector consists of a LSO array, a custom acrylic light guide, a 3 × 3 multi-pixel photon counter (MPPC) array (S10362-11-050P, Hamamatsu Photonics, Japan) and a readout board with a charge division resistor network. The LSO array consists of 100 crystals, each measuring 0.8 × 0.8 × 3 mm3 and arranged in 0.86 mm pitches. A Monte Carlo simulation was used to aid the design and fabrication of a custom light guide to control distribution of scintillation light over the surface of the MPPC array. The output signals of the nine MPPC are multiplexed by a charge division resistor network to generate four position-encoded analog outputs. Flood image, energy resolution and timing resolution measurements were performed using standard NIM electronics. The linearity of the detector response was investigated using gamma-ray sources of different energies. The 10 × 10 array of 0.8 mm LSO crystals was clearly resolved in the flood image. The average energy resolution and standard deviation were 20.0% full-width at half-maximum (FWHM) and ±5.0%, respectively, at 511 keV. The timing resolution of a single MPPC coupled to a LSO crystal was found to be 857 ps FWHM, and the value for the central region of detector module was 1182 ps FWHM when ±10% energy window was applied. The nonlinear response of a single MPPC when used to read out a single LSO was observed among the corner crystals of the proposed detector module. However, the central region of the detector module exhibits significantly less nonlinearity (6.5% for 511 keV). These results demonstrate that (1) a charge-sharing resistor network can effectively multiplex MPPC signals and reduce the number of output signals without significantly degrading the performance of a PET detector and (2) a custom light guide to permit light sharing

  19. Velocity-resolved Hot Water Emission Detected toward HL Tau with the Submillimeter Array

    Science.gov (United States)

    Kristensen, Lars E.; Brown, Joanna M.; Wilner, David; Salyk, Colette

    2016-05-01

    Using the Submillimeter Array (SMA) on Mauna Kea, the {{{H}}}216{{O}} {10}{2,9}-9{}{3,6} transition ({E}{{up}} = 1863 K) at 321.2 GHz has been detected toward the embedded low-mass protostar HL Tau. The line centroid is blueshifted by 20 km s-1 with respect to the source velocity, and it has a FWHM of 25 km s-1. The emission is tentatively resolved and extends ˜3″-4″ over the sky (˜2 beams), or ˜500 au at the distance of Taurus. The velocity offset, and to a lesser degree the spatial extent of the emission, show that the line originates in the protostellar jet or wind. This result suggests that at least some water emission observed with Herschel and Spitzer toward embedded sources, and perhaps also disk sources, contains a wind or jet component, which is crucial for interpreting these data. These pathfinder observations done with the SMA open a new window into studying the origin of water emission with e.g., ALMA, thus providing new insights into where water is in protostellar systems.

  20. Submillimeter Array 12CO (2-1) Imaging of the NGC 6946 Giant Molecular Clouds

    Science.gov (United States)

    Wu, Ya-Lin; Sakamoto, Kazushi; Pan, Hsi-An

    2017-04-01

    We present a 12CO (2-1) mosaic map of the spiral galaxy NGC 6946 by combining data from the Submillimeter Array and the IRAM 30 m telescope. We identify 390 giant molecular clouds (GMCs) from the nucleus to 4.5 kpc in the disk. GMCs in the inner 1 kpc are generally more luminous and turbulent, some of which have luminosities >106 K km s-1 pc2 and velocity dispersions >10 km s-1. Large-scale bar-driven dynamics likely regulate GMC properties in the nuclear region. Similar to the Milky Way and other disk galaxies, GMC mass function of NGC 6946 has a shallower slope (index > -2) in the inner region, and a steeper slope (index outer region. This difference in mass spectra may be indicative of different cloud formation pathways: gravitational instabilities might play a major role in the nuclear region, while cloud coalescence might be dominant in the outer disk. Finally, the NGC 6946 clouds are similar to those in M33 in terms of statistical properties, but they are generally less luminous and turbulent than the M51 clouds.

  1. Gravitational lens models based on submillimeter array imaging of Herschel -selected strongly lensed sub-millimeter galaxies at z > 1.5

    Energy Technology Data Exchange (ETDEWEB)

    Bussmann, R. S.; Gurwell, M. A. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Pérez-Fournon, I. [Instituto de Astrofísica de Canarias (IAC), E-38200 La Laguna, Tenerife (Spain); Amber, S. [Department of Physical Sciences, The Open University, Milton Keynes MK7 6AA (United Kingdom); Calanog, J.; De Bernardis, F.; Wardlow, J. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Dannerbauer, H. [Laboratoire AIM-Paris-Saclay, CEA/DSM/Irfu-CNRS-Université Paris Diderot, CE-Saclay, pt courrier 131, F-91191 Gif-sur-Yvette (France); Fu, Hai [Department of Physics and Astronomy, The University of Iowa, 203 Van Allen Hall, Iowa City, IA 52242 (United States); Harris, A. I. [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States); Krips, M. [Institut de RadioAstronomie Millimétrique, 300 Rue de la Piscine, Domaine Universitaire, 38406 Saint Martin d' Hères (France); Lapi, A. [Department Fisica, Univ. Tor Vergata, Via Ricerca Scientifica 1, 00133 Rome, Italy and SISSA, Via Bonomea 265, 34136 Trieste (Italy); Maiolino, R. [Cavendish Laboratory, University of Cambridge, 19 J.J. Thomson Ave., Cambridge CB3 OHE (United Kingdom); Omont, A. [Institut d' Astrophysique de Paris, UMR 7095, CNRS, UPMC Univ. Paris 06, 98bis boulevard Arago, F-75014 Paris (France); Riechers, D. [Department of Astronomy, Space Science Building, Cornell University, Ithaca, NY 14853-6801 (United States); Baker, A. J. [Department of Physics and Astronomy, Rutgers, The State University of New Jersey, 136 Frelinghuysen Rd, Piscataway, NJ 08854 (United States); Birkinshaw, M. [HH Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Bock, J. [California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125 (United States); and others

    2013-12-10

    Strong gravitational lenses are now being routinely discovered in wide-field surveys at (sub-)millimeter wavelengths. We present Submillimeter Array (SMA) high-spatial resolution imaging and Gemini-South and Multiple Mirror Telescope optical spectroscopy of strong lens candidates discovered in the two widest extragalactic surveys conducted by the Herschel Space Observatory: the Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS) and the Herschel Multi-tiered Extragalactic Survey (HerMES). From a sample of 30 Herschel sources with S {sub 500} > 100 mJy, 21 are strongly lensed (i.e., multiply imaged), 4 are moderately lensed (i.e., singly imaged), and the remainder require additional data to determine their lensing status. We apply a visibility-plane lens modeling technique to the SMA data to recover information about the masses of the lenses as well as the intrinsic (i.e., unlensed) sizes (r {sub half}) and far-infrared luminosities (L {sub FIR}) of the lensed submillimeter galaxies (SMGs). The sample of lenses comprises primarily isolated massive galaxies, but includes some groups and clusters as well. Several of the lenses are located at z {sub lens} > 0.7, a redshift regime that is inaccessible to lens searches based on Sloan Digital Sky Survey spectroscopy. The lensed SMGs are amplified by factors that are significantly below statistical model predictions given the 500 μm flux densities of our sample. We speculate that this may reflect a deficiency in our understanding of the intrinsic sizes and luminosities of the brightest SMGs. The lensed SMGs span nearly one decade in L {sub FIR} (median L {sub FIR} = 7.9 × 10{sup 12} L {sub ☉}) and two decades in FIR luminosity surface density (median Σ{sub FIR} = 6.0 × 10{sup 11} L {sub ☉} kpc{sup –2}). The strong lenses in this sample and others identified via (sub-)mm surveys will provide a wealth of information regarding the astrophysics of galaxy formation and evolution over a wide range in redshift.

  2. SUBMILLIMETER ARRAY AND SPITZER OBSERVATIONS OF BOK GLOBULE CB 17: A CANDIDATE FIRST HYDROSTATIC CORE?

    Energy Technology Data Exchange (ETDEWEB)

    Chen Xuepeng; Arce, Hector G.; Dunham, Michael M. [Department of Astronomy, Yale University, Box 208101, New Haven, CT 06520-8101 (United States); Zhang Qizhou; Bourke, Tyler L. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Launhardt, Ralf; Schmalzl, Markus; Henning, Thomas, E-mail: xuepeng.chen@yale.edu [Max Planck Institute for Astronomy, Koenigstuhl 17, D-69117 Heidelberg (Germany)

    2012-06-01

    We present high angular resolution Submillimeter Array (SMA) and Spitzer observations toward the Bok globule CB 17. SMA 1.3 mm dust continuum images reveal within CB 17 two sources with an angular separation of {approx}21'' ({approx}5250 AU at a distance of {approx}250 pc). The northwestern continuum source, referred to as CB 17 IRS, dominates the infrared emission in the Spitzer images, drives a bipolar outflow extending in the northwest-southeast direction, and is classified as a low-luminosity Class 0/I transition object (L{sub bol} {approx} 0.5 L{sub Sun }). The southeastern continuum source, referred to as CB 17 MMS, has faint dust continuum emission in the SMA 1.3 mm observations ({approx}6{sigma} detection; {approx}3.8 mJy), but is not detected in the deep Spitzer infrared images at wavelengths from 3.6 to 70 {mu}m. Its bolometric luminosity and temperature, estimated from its spectral energy distribution, are {<=}0.04 L{sub Sun} and {<=}16 K, respectively. The SMA CO (2-1) observations suggest that CB 17 MMS may drive a low-velocity molecular outflow ({approx}2.5 km s{sup -1}), extending in the east-west direction. Comparisons with prestellar cores and Class 0 protostars suggest that CB 17 MMS is more evolved than prestellar cores but less evolved than Class 0 protostars. The observed characteristics of CB 17 MMS are consistent with the theoretical predictions from radiative/magnetohydrodynamical simulations of a first hydrostatic core, but there is also the possibility that CB 17 MMS is an extremely low luminosity protostar deeply embedded in an edge-on circumstellar disk. Further observations are needed to study the properties of CB 17 MMS and to address more precisely its evolutionary stage.

  3. Observing the Sun with the Atacama Large Millimeter/submillimeter Array (ALMA): High-Resolution Interferometric Imaging

    Science.gov (United States)

    Shimojo, M.; Bastian, T. S.; Hales, A. S.; White, S. M.; Iwai, K.; Hills, R. E.; Hirota, A.; Phillips, N. M.; Sawada, T.; Yagoubov, P.; Siringo, G.; Asayama, S.; Sugimoto, M.; Brajša, R.; Skokić, I.; Bárta, M.; Kim, S.; de Gregorio-Monsalvo, I.; Corder, S. A.; Hudson, H. S.; Wedemeyer, S.; Gary, D. E.; De Pontieu, B.; Loukitcheva, M.; Fleishman, G. D.; Chen, B.; Kobelski, A.; Yan, Y.

    2017-07-01

    Observations of the Sun at millimeter and submillimeter wavelengths offer a unique probe into the structure, dynamics, and heating of the chromosphere; the structure of sunspots; the formation and eruption of prominences and filaments; and energetic phenomena such as jets and flares. High-resolution observations of the Sun at millimeter and submillimeter wavelengths are challenging due to the intense, extended, low-contrast, and dynamic nature of emission from the quiet Sun, and the extremely intense and variable nature of emissions associated with energetic phenomena. The Atacama Large Millimeter/submillimeter Array (ALMA) was designed with solar observations in mind. The requirements for solar observations are significantly different from observations of sidereal sources and special measures are necessary to successfully carry out this type of observations. We describe the commissioning efforts that enable the use of two frequency bands, the 3-mm band (Band 3) and the 1.25-mm band (Band 6), for continuum interferometric-imaging observations of the Sun with ALMA. Examples of high-resolution synthesized images obtained using the newly commissioned modes during the solar-commissioning campaign held in December 2015 are presented. Although only 30 of the eventual 66 ALMA antennas were used for the campaign, the solar images synthesized from the ALMA commissioning data reveal new features of the solar atmosphere that demonstrate the potential power of ALMA solar observations. The ongoing expansion of ALMA and solar-commissioning efforts will continue to enable new and unique solar observing capabilities.

  4. Advanced Amplifier Based Receiver Front Ends for Submillimeter-Wave-Sounders Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Develop high electron mobility transistor (HEMT) amplifier based heterodyne radiometers to provide high sensitivity at millimeter and submillimeter wavelengths with...

  5. A DETAILED GRAVITATIONAL LENS MODEL BASED ON SUBMILLIMETER ARRAY AND KECK ADAPTIVE OPTICS IMAGING OF A HERSCHEL-ATLAS SUBMILLIMETER GALAXY AT z = 4.243 {sup ,} {sup ,}

    Energy Technology Data Exchange (ETDEWEB)

    Bussmann, R. S.; Gurwell, M. A. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Fu Hai; Cooray, A. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Smith, D. J. B.; Bonfield, D.; Dunne, L. [Centre for Astrophysics, Science and Technology Research Institute, University of Hertfordshire, Hatfield, Herts AL10 9AB (United Kingdom); Dye, S.; Eales, S. [School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom); Auld, R. [Cardiff University, School of Physics and Astronomy, Queens Buildings, The Parade, Cardiff CF24 3AA (United Kingdom); Baes, M.; Fritz, J. [Sterrenkundig Observatorium, Universiteit Gent, Krijgslaan 281 S9, B-9000 Gent (Belgium); Baker, A. J. [Department of Physics and Astronomy, Rutgers, the State University of New Jersey, 136 Frelinghuysen Road, Piscataway, NJ 08854-8019 (United States); Cava, A. [Departamento de Astrofisica, Facultad de CC. Fisicas, Universidad Complutense de Madrid, E-28040 Madrid (Spain); Clements, D. L.; Dariush, A. [Imperial College London, Blackett Laboratory, Prince Consort Road, London SW7 2AZ (United Kingdom); Coppin, K. [Department of Physics, McGill University, Ernest Rutherford Building, 3600 Rue University, Montreal, Quebec, H3A 2T8 (Canada); Dannerbauer, H. [Universitaet Wien, Institut fuer Astronomie, Tuerkenschanzstrasse 17, 1180 Wien, Oesterreich (Austria); De Zotti, G. [Universita di Padova, Dipto di Astronomia, Vicolo dell' Osservatorio 2, IT 35122, Padova (Italy); Hopwood, R., E-mail: rbussmann@cfa.harvard.edu [Department of Physics and Astronomy, Open University, Walton Hall, Milton Keynes, MK7 6AA (United Kingdom); and others

    2012-09-10

    We present high-spatial resolution imaging obtained with the Submillimeter Array (SMA) at 880 {mu}m and the Keck adaptive optics (AO) system at the K{sub S}-band of a gravitationally lensed submillimeter galaxy (SMG) at z = 4.243 discovered in the Herschel Astrophysical Terahertz Large Area Survey. The SMA data (angular resolution Almost-Equal-To 0.''6) resolve the dust emission into multiple lensed images, while the Keck AO K{sub S}-band data (angular resolution Almost-Equal-To 0.''1) resolve the lens into a pair of galaxies separated by 0.''3. We present an optical spectrum of the foreground lens obtained with the Gemini-South telescope that provides a lens redshift of z{sub lens} = 0.595 {+-} 0.005. We develop and apply a new lens modeling technique in the visibility plane that shows that the SMG is magnified by a factor of {mu} = 4.1 {+-} 0.2 and has an intrinsic infrared (IR) luminosity of L{sub IR} = (2.1 {+-} 0.2) Multiplication-Sign 10{sup 13} L{sub Sun }. We measure a half-light radius of the background source of r{sub s} = 4.4 {+-} 0.5 kpc which implies an IR luminosity surface density of {Sigma}{sub IR} (3.4 {+-} 0.9) Multiplication-Sign 10{sup 11} L{sub Sun} kpc{sup -2}, a value that is typical of z > 2 SMGs but significantly lower than IR luminous galaxies at z {approx} 0. The two lens galaxies are compact (r{sub lens} Almost-Equal-To 0.9 kpc) early-types with Einstein radii of {theta}{sub E1} 0.57 {+-} 0.01 and {theta}{sub E2} = 0.40 {+-} 0.01 that imply masses of M{sub lens1} = (7.4 {+-} 0.5) Multiplication-Sign 10{sup 10} M{sub Sun} and M{sub lens2} = (3.7 {+-} 0.3) Multiplication-Sign 10{sup 10} M{sub Sun }. The two lensing galaxies are likely about to undergo a dissipationless merger, and the mass and size of the resultant system should be similar to other early-type galaxies at z {approx} 0.6. This work highlights the importance of high spatial resolution imaging in developing models of strongly lensed galaxies

  6. CCAT Heterodyne Instrument Development Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A key challenge in building a large pixel heterodyne array is efficiently and simultaneously delivering the astronomical signal and local oscillator power to each...

  7. MEASURING MASS ACCRETION RATE ONTO THE SUPERMASSIVE BLACK HOLE IN M87 USING FARADAY ROTATION MEASURE WITH THE SUBMILLIMETER ARRAY

    Energy Technology Data Exchange (ETDEWEB)

    Kuo, C. Y.; Asada, K.; Rao, R.; Nakamura, M.; Algaba, J. C.; Liu, H. B.; Inoue, M.; Koch, P. M.; Ho, P. T. P.; Matsushita, S.; Pu, H.-Y.; Nishioka, H.; Pradel, N. [Academia Sinica, Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan (China); Akiyama, K. [National Astronomical Observatory of Japan, Osawa 2-21-1, Mitaka, Tokyo 181-8588 (Japan)

    2014-03-10

    We present the first constraint on the Faraday rotation measure (RM) at submillimeter wavelengths for the nucleus of M87. By fitting the polarization position angles (χ) observed with the Submillimeter Array at four independent frequencies around ∼230 GHz and interpreting the change in χ as a result of external Faraday rotation associated with accretion flow, we determine the RM of the M87 core to be between –7.5 × 10{sup 5} and 3.4 × 10{sup 5} rad m{sup –2}. Assuming a density profile of the accretion flow that follows a power-law distribution and a magnetic field that is ordered, radial, and has equipartition strength, the limit on the RM constrains the mass accretion rate M-dot to be below 9.2 × 10{sup –4} M {sub ☉} yr{sup –1} at a distance of 21 Schwarzschild radii from the central black hole. This value is at least two orders of magnitude smaller than the Bondi accretion rate, suggesting significant suppression of the accretion rate in the inner region of the accretion flow. Consequently, our result disfavors the classical advection-dominated accretion flow and prefers the adiabatic inflow-outflow solution or convection-dominated accretion flow for the hot accretion flow in M87.

  8. The kilopixel array pathfinder project (KAPPa), a 16-pixel integrated heterodyne focal plane array: characterization of the single pixel prototype

    Science.gov (United States)

    Wheeler, Caleb H.; Groppi, Christopher E.; Mani, Hamdi; McGarey, Patrick; Kuenzi, Linda; Weinreb, Sander; Russell, Damon S.; Kooi, Jacob W.; Lichtenberger, Arthur W.; Walker, Christopher K.; Kulesa, Craig

    2014-07-01

    We report on the laboratory testing of KAPPa, a 16-pixel proof-of-concept array to enable the creation THz imaging spectrometer with ~1000 pixels. Creating an array an order of magnitude larger than the existing state of the art of 64 pixels requires a simple and robust design as well as improvements to mixer selection, testing, and assembly. Our testing employs a single pixel test bench where a novel 2D array architecture is tested. The minimum size of the footprint is dictated by the diameter of the drilled feedhorn aperture. In the adjoining detector block, a 6mm × 6mm footprint houses the SIS mixer, LNA, matching and bias networks, and permanent magnet. We present an initial characterization of the single pixel prototype using a computer controlled test bench to determine Y-factors for a parameter space of LO power, LO frequency, IF bandwidth, magnet field strength, and SIS bias voltage. To reduce the need to replace poorly preforming pixels that are already mounted in a large format array, we show techniques to improve SIS mixer selection prior to mounting in the detector block. The 2D integrated 16-pixel array design has been evolved as we investigate the properties of the single pixel prototype. Carful design of the prototype has allowed for rapid translation of single pixel design improvements to be easily incorporated into the 16-pixel model.

  9. Photon heterodyning.

    Science.gov (United States)

    Okawa, Youhei; Omura, Fuminori; Yasutake, Yuhsuke; Fukatsu, Susumu

    2017-08-21

    Single-photon interference experiments are attempted in the time domain using true single-photon streams. Self-heterodyning beats are clearly observed by letting the field associated with a single photon interfere with itself on a field-quadratic detector, which is a time analogue of Young's two-slit interference experiment. The temporal first-order coherence of single-photon fields, i.e., transient interference fringes, develops as cumulative detection events are mapped point-by-point onto a virtual capture frame by properly correlating the time-series data. The ability to single out photon counts at a designated timing paves the way for digital heterodyning with faint light for such use as phase measurement and quantum information processing.

  10. Performance evaluation of a sub-millimeter spatial resolution PET detector module using a digital silicon photomultiplier coupled LGSO array

    Science.gov (United States)

    Leem, Hyun Tae; Choi, Yong; Kim, Kyu Bom; Lee, Sangwon; Yamamoto, Seiichi; Yeom, Jung-Yeol

    2017-02-01

    In positron emission tomography (PET) for breast, brain and small animal imaging, the spatial resolution of a PET detector is crucial to obtain high quality PET images. In this study, a PET detector for sub-millimeter spatial resolution imaging purpose was assembled using 4×4 pixels of a digital silicon photomultiplier (dSiPM, DPC-3200-22-44, Philips) coupled with a 15×15 LGSO array with BaSO4 reflector, and a 1 mm thick acrylic light guide for light distribution between the dSiPM pixels. The active area of each dSiPM pixel was 3.2×3.9 mm2 and the size of each LGSO scintillator element was 0.7×0.7×6 mm3. In this paper, we experimentally demonstrated the performance of the PET detector by measuring the energy resolution, 2D flood map, peak to valley (P/V) ratio, and coincidence resolving time (CRT). All measurements were performed at a temperature of 10±1 ℃. The average energy resolution was 15.6% (without correcting for saturation effects) at 511 keV and the best CRT was 242±5 ps. The 2D flood map obtained with an energy window of 400-600 keV demonstrated clear identification of all pixels, and the average P/V ratio of the X- and Y-directions were 7.31 and 7.81, respectively. This study demonstrated that the PET detector could be suitable for application in high resolution PET while achieving good timing resolution.

  11. Performance evaluation of a sub-millimeter spatial resolution PET detector module using a digital silicon photomultiplier coupled LGSO array

    Energy Technology Data Exchange (ETDEWEB)

    Leem, Hyun Tae [Molecular Imaging Research & Education (MiRe) Laboratory, Department of Electronic Engineering, Sogang University, Seoul (Korea, Republic of); Choi, Yong, E-mail: ychoi@sogang.ac.kr [Molecular Imaging Research & Education (MiRe) Laboratory, Department of Electronic Engineering, Sogang University, Seoul (Korea, Republic of); Kim, Kyu Bom; Lee, Sangwon [Molecular Imaging Research & Education (MiRe) Laboratory, Department of Electronic Engineering, Sogang University, Seoul (Korea, Republic of); Yamamoto, Seiichi [Department of Medical Technology, Nagoya University Graduate School of Medicine, Nagoya (Japan); Yeom, Jung-Yeol, E-mail: jungyeol@korea.ac.kr [School of Biomedical Engineering, Korea University, Seoul (Korea, Republic of)

    2017-02-21

    In positron emission tomography (PET) for breast, brain and small animal imaging, the spatial resolution of a PET detector is crucial to obtain high quality PET images. In this study, a PET detector for sub-millimeter spatial resolution imaging purpose was assembled using 4×4 pixels of a digital silicon photomultiplier (dSiPM, DPC-3200-22-44, Philips) coupled with a 15×15 LGSO array with BaSO{sub 4} reflector, and a 1 mm thick acrylic light guide for light distribution between the dSiPM pixels. The active area of each dSiPM pixel was 3.2×3.9 mm{sup 2} and the size of each LGSO scintillator element was 0.7×0.7×6 mm{sup 3}. In this paper, we experimentally demonstrated the performance of the PET detector by measuring the energy resolution, 2D flood map, peak to valley (P/V) ratio, and coincidence resolving time (CRT). All measurements were performed at a temperature of 10±1 ℃. The average energy resolution was 15.6% (without correcting for saturation effects) at 511 keV and the best CRT was 242±5 ps. The 2D flood map obtained with an energy window of 400–600 keV demonstrated clear identification of all pixels, and the average P/V ratio of the X- and Y-directions were 7.31 and 7.81, respectively. This study demonstrated that the PET detector could be suitable for application in high resolution PET while achieving good timing resolution.

  12. Observing the Sun with the Atacama Large Millimeter/submillimeter Array (ALMA): Fast-Scan Single-Dish Mapping

    Science.gov (United States)

    White, S. M.; Iwai, K.; Phillips, N. M.; Hills, R. E.; Hirota, A.; Yagoubov, P.; Siringo, G.; Shimojo, M.; Bastian, T. S.; Hales, A. S.; Sawada, T.; Asayama, S.; Sugimoto, M.; Marson, R. G.; Kawasaki, W.; Muller, E.; Nakazato, T.; Sugimoto, K.; Brajša, R.; Skokić, I.; Bárta, M.; Kim, S.; Remijan, A. J.; de Gregorio, I.; Corder, S. A.; Hudson, H. S.; Loukitcheva, M.; Chen, B.; De Pontieu, B.; Fleishmann, G. D.; Gary, D. E.; Kobelski, A.; Wedemeyer, S.; Yan, Y.

    2017-07-01

    The Atacama Large Millimeter/submillimeter Array (ALMA) radio telescope has commenced science observations of the Sun starting in late 2016. Since the Sun is much larger than the field of view of individual ALMA dishes, the ALMA interferometer is unable to measure the background level of solar emission when observing the solar disk. The absolute temperature scale is a critical measurement for much of ALMA solar science, including the understanding of energy transfer through the solar atmosphere, the properties of prominences, and the study of shock heating in the chromosphere. In order to provide an absolute temperature scale, ALMA solar observing will take advantage of the remarkable fast-scanning capabilities of the ALMA 12 m dishes to make single-dish maps of the full Sun. This article reports on the results of an extensive commissioning effort to optimize the mapping procedure, and it describes the nature of the resulting data. Amplitude calibration is discussed in detail: a path that uses the two loads in the ALMA calibration system as well as sky measurements is described and applied to commissioning data. Inspection of a large number of single-dish datasets shows significant variation in the resulting temperatures, and based on the temperature distributions, we derive quiet-Sun values at disk center of 7300 K at λ = 3 mm and 5900 K at λ = 1.3 mm. These values have statistical uncertainties of about 100 K, but systematic uncertainties in the temperature scale that may be significantly larger. Example images are presented from two periods with very different levels of solar activity. At a resolution of about 25'', the 1.3 mm wavelength images show temperatures on the disk that vary over about a 2000 K range. Active regions and plages are among the hotter features, while a large sunspot umbra shows up as a depression, and filament channels are relatively cool. Prominences above the solar limb are a common feature of the single-dish images.

  13. DIRECT DETECTION OF PRECURSORS OF GAS GIANTS FORMED BY GRAVITATIONAL INSTABILITY WITH THE ATACAMA LARGE MILLIMETER/SUBMILLIMETER ARRAY

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, Lucio [Center for Theoretical Astrophysics and Cosmology, Institute for Computational Science, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich (Switzerland); Peters, Thomas [Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, D-85748 Garching (Germany); Pineda, Jaime E. [Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse 1, D-85748 Garching (Germany); Wadsley James; Rogers, Patrick, E-mail: p.rogers@marianopolis.edu [Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1 (Canada)

    2016-06-01

    Phases of gravitational instability are expected in the early phases of disk evolution, when the disk mass is still a substantial fraction of the mass of the star. Disk fragmentation into sub-stellar objects could occur in the cold exterior part of the disk. Direct detection of massive gaseous clumps on their way to collapse into gas giant planets would offer an unprecedented test of the disk instability model. Here we use state-of-the-art 3D radiation-hydro simulations of disks undergoing fragmentation into massive gas giants, post-processed with RADMC-3D to produce dust continuum emission maps. These are then fed into the Common Astronomy Software Applications (CASA) ALMA simulator. The synthetic maps show that both overdense spiral arms and actual clumps at different stages of collapse can be detected with the Atacama Large Millimeter/submillimeter Array (ALMA) in the full configuration at the distance of the Ophiuchus star forming region (125 pc). The detection of clumps is particularly effective at shorter wavelengths (690 GHz) combining two resolutions with multi-scale clean. Furthermore, we show that a flux-based estimate of the mass of a protoplanetary clump can be comparable to a factor of three higher than the gravitationally bound clump mass. The estimated mass depends on the assumed opacity, and on the gas temperature, which should be set using the input of radiation-hydro simulations. We conclude that ALMA has the capability to detect “smoking gun” systems that are a signpost of the disk instability model for gas giant planet formation.

  14. Laser Heterodyning

    CERN Document Server

    Protopopov, Vladimir V

    2009-01-01

    Laser heterodyning is now a widespread optical technique, based on interference of two waves with slightly different frequencies within the sensitive area of a photo-detector. Its unique feature – preserving phase information about optical wave in the electrical signal of the photo-detector – finds numerous applications in various domains of applied optics and optoelectronics: in spectroscopy, polarimetry, radiometry, laser radars and Lidars, microscopy and other areas. The reader may be surprised by a variety of disciplines that this book covers and satisfied by detailed explanation of the phenomena. Very well illustrated, this book will be helpful for researches, postgraduates and students, working in applied optics.

  15. Dielectric Covered Planar Antennas at Submillimeter Wavelengths for Terahertz Imaging

    Science.gov (United States)

    Chattopadhyay, Goutam; Gill, John J.; Skalare, Anders; Lee, Choonsup; Llombart, Nuria; Siegel, Peter H.

    2011-01-01

    Most optical systems require antennas with directive patterns. This means that the physical area of the antenna will be large in terms of the wavelength. When non-cooled systems are used, the losses of microstrip or coplanar waveguide lines impede the use of standard patch or slot antennas for a large number of elements in a phased array format. Traditionally, this problem has been solved by using silicon lenses. However, if an array of such highly directive antennas is to be used for imaging applications, the fabrication of many closely spaced lenses becomes a problem. Moreover, planar antennas are usually fed by microstrip or coplanar waveguides while the mixer or the detector elements (usually Schottky diodes) are coupled in a waveguide environment. The coupling between the antenna and the detector/ mixer can be a fabrication challenge in an imaging array at submillimeter wavelengths. Antennas excited by a waveguide (TE10) mode makes use of dielectric superlayers to increase the directivity. These antennas create a kind of Fabry- Perot cavity between the ground plane and the first layer of dielectric. In reality, the antenna operates as a leaky wave mode where a leaky wave pole propagates along the cavity while it radiates. Thanks to this pole, the directivity of a small antenna is considerably enhanced. The antenna consists of a waveguide feed, which can be coupled to a mixer or detector such as a Schottky diode via a standard probe design. The waveguide is loaded with a double-slot iris to perform an impedance match and to suppress undesired modes that can propagate on the cavity. On top of the slot there is an air cavity and on top, a small portion of a hemispherical lens. The fractional bandwidth of such antennas is around 10 percent, which is good enough for heterodyne imaging applications.The new geometry makes use of a silicon lens instead of dielectric quarter wavelength substrates. This design presents several advantages when used in the submillimeter

  16. A novel gamma-ray detector with submillimeter resolutions using a monolithic MPPC array with pixelized Ce:LYSO and Ce:GGAG crystals

    Energy Technology Data Exchange (ETDEWEB)

    Kato, T., E-mail: katou.frme.8180@asagi.waseda.jp [Research Institute for Science and Engineering, Waseda University, 3-4-1, Ohkubo, Shinjuku, Tokyo (Japan); Kataoka, J.; Nakamori, T.; Miura, T.; Matsuda, H.; Kishimoto, A. [Research Institute for Science and Engineering, Waseda University, 3-4-1, Ohkubo, Shinjuku, Tokyo (Japan); Sato, K.; Ishikawa, Y.; Yamamura, K.; Nakamura, S.; Kawabata, N. [Solid State Division, Hamamatsu Photonics K. K., 1126-1, Ichino-cho, Hamamatsu, Shizuoka (Japan); Ikeda, H. [ISAS/JAXA, 3-1-1, Yoshinodai, Chuo-ku, Sagamihara-shi, Kanagawa (Japan); Yamamoto, S. [Kobe City College of Technology, 8-3, Gakuenhigashimati, Nishi-ku, Kobe-shi, Hyougo 651-2194 (Japan); Kamada, K. [Materials Research Laboratory, Furukawa Co., Ltd., 1-25-13, Kannondai, Tsukuba, Ibaraki 305-0856 (Japan)

    2013-01-21

    We have developed a large-area monolithic Multi-Pixel Photon Counter (MPPC) array consisting of 4×4 channels with a three-side buttable package. Each channel has a photosensitive area of 3×3 mm{sup 2} and 3600 Geiger mode avalanche photodiodes (APDs). For typical operational gain of 7.5×10{sup 5} at +20 °C, gain fluctuation over the entire MPPC device is only ±5.6%, and dark count rates (as measured at the 1 p.e. level) amount to ≤400kcps per channel. We first fabricated a gamma-ray camera consisting of the MPPC array with one-to-one coupling to a Ce-doped (Lu,Y){sub 2}(SiO{sub 4})O (Ce:LYSO) crystal array (4×4 array of 3×3×10 mm{sup 3} crystals). Energy and time resolutions of 11.5±0.5% (FWHM at 662 keV) and 493±22ps were obtained, respectively. When using the charge division resistor network, which compiles signals into four position-encoded analog outputs, the ultimate positional resolution is estimated as 0.19 mm in both X and Y directions, while energy resolution of 10.2±0.4% (FWHM) was obtained. Finally, we fabricated submillimeter Ce:LYSO and Ce-doped Gd{sub 3}Ga{sub 3}Al{sub 2}O{sub 12} (Ce:GGAG) scintillator matrices each consisting of 1.0×1.0, 0.7×0.7 and 0.5×0.5 mm{sup 2} pixels, to further improve the spatial resolution. In all types of Ce:LYSO and Ce:GGAG matrices, each crystal was clearly resolved in the position histograms when irradiated by a {sup 137}Cs source. The energy resolutions for 662 keV gamma-rays for each Ce:LYSO and Ce:GGAG scintillator matrix were ≤14.3%. These results suggest excellent potential for its use as a high spatial medical imaging device, particularly in positron emission tomography (PET). -- Highlights: ► We developed a newly designed large-area monolithic MPPC array. ► We obtained fine gain uniformity, and good energy and time resolutions when coupled to the LYSO scintillator. ► We fabricated gamma-ray camera consisting of the MPPC array and submillimeter pixelized LYSO and GGAG scintillators. ► In

  17. SUBMILLIMETER ARRAY OBSERVATIONS OF MAGNETIC FIELDS IN G240.31+0.07: AN HOURGLASS IN A MASSIVE CLUSTER-FORMING CORE

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Keping [School of Astronomy and Space Science, Nanjing University, 22 Hankou Road, Nanjing 210093 (China); Zhang, Qizhou [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Menten, Karl M. [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Liu, Hauyu B.; Tang, Ya-Wen [Academia Sinica Institute of Astronomy and Astrophysics, P. O. Box 23-141, Taipei 106, Taiwan (China); Girart, Josep M., E-mail: kpqiu@nju.edu.cn [Institut de Ciències de l' Espai (CSIC-IEEC), Campus UAB, Facultat de Ciències, C5p 2, E-08193 Bellaterra, Catalonia (Spain)

    2014-10-10

    We report the first detection of an hourglass magnetic field aligned with a well-defined outflow rotation system in a high-mass, star-forming region. The observations were performed with the Submillimeter Array toward G240.31+0.07, which harbors a massive, flattened, and fragmenting molecular cloud core and a wide-angle bipolar outflow. The polarized dust emission at 0.88 mm reveals a clear hourglass-shaped magnetic field aligned within 20° of the outflow axis. Maps of high-density tracing spectral lines, e.g., H{sup 13}CO{sup +} (4-3), show that the core is rotating about its minor axis, which is also aligned with the magnetic field axis. Therefore, both the magnetic field and kinematic properties observed in this region are surprisingly consistent with the theoretical predictions of the classic paradigm of isolated low-mass star formation. The strength of the magnetic field in the plane of sky is estimated to be ∼1.1 mG, resulting in a mass-to-magnetic flux ratio of 1.4 times the critical value and a turbulent-to-ordered magnetic energy ratio of 0.4. We also find that the specific angular momentum almost linearly decreases from r ∼ 0.6 pc to 0.03 pc scales, which is most likely attributed to magnetic braking.

  18. Filters for Submillimeter Electromagnetic Waves

    Science.gov (United States)

    Berdahl, C. M.

    1986-01-01

    New manufacturing process produces filters strong, yet have small, precise dimensions and smooth surface finish essential for dichroic filtering at submillimeter wavelengths. Many filters, each one essentially wafer containing fine metal grid made at same time. Stacked square wires plated, fused, and etched to form arrays of holes. Grid of nickel and tin held in brass ring. Wall thickness, thickness of filter (hole depth) and lateral hole dimensions all depend upon operating frequency and filter characteristics.

  19. SUBMM heterodyne mixing using NbCN/Nb SIS tunnel junctions.

    NARCIS (Netherlands)

    vandeStadt, H; Mees, J; Barber, Z; Blamire, M; Dieleman, P; deGraauw, T

    We describe heterodyne mixing experiments with NbCN/Nb quasi-particle tunnel junctions at submillimeter wavelengths. In this wavelength range junctions with niobium nitride as superconducting material are promising because of the high gap voltage, about 5.7 mV, as compared to 3 mV for the more

  20. Design and Fabrication of Two-Dimensional Semiconducting Bolometer Arrays for the High Resolution Airborne Wideband Camera (HAWC) and the Submillimeter High Angular Resolution Camera II (SHARC-II)

    Science.gov (United States)

    Voellmer, George M.; Allen, Christine A.; Amato, Michael J.; Babu, Sachidananda R.; Bartels, Arlin E.; Benford, Dominic J.; Derro, Rebecca J.; Dowell, C. Darren; Harper, D. Al; Jhabvala, Murzy D.

    2002-01-01

    The High resolution Airborne Wideband Camera (HAWC) and the Submillimeter High Angular Resolution Camera II (SHARC II) will use almost identical versions of an ion-implanted silicon bolometer array developed at the National Aeronautics and Space Administration's Goddard Space Flight Center (GSFC). The GSFC 'Pop-up' Detectors (PUD's) use a unique folding technique to enable a 12 x 32-element close-packed array of bolometers with a filling factor greater than 95 percent. A kinematic Kevlar(trademark) suspension system isolates the 200 mK bolometers from the helium bath temperature, and GSFC - developed silicon bridge chips make electrical connection to the bolometers, while maintaining thermal isolation. The JFET preamps operate at 120 K. Providing good thermal heat sinking for these, and keeping their conduction and radiation from reaching the nearby bolometers, is one of the principal design challenges encountered. Another interesting challenge is the preparation of the silicon bolometers. They are manufactured in 32-element, planar rows using Micro Electro Mechanical Systems (MEMS) semiconductor etching techniques, and then cut and folded onto a ceramic bar. Optical alignment using specialized jigs ensures their uniformity and correct placement. The rows are then stacked to create the 12 x 32-element array. Engineering results from the first light run of SHARC II at the Caltech Submillimeter Observatory (CSO) are presented.

  1. Submillimeter observations of the sun from the James Clerk Maxwell Telescope

    Energy Technology Data Exchange (ETDEWEB)

    Lindsey, C.A.; Yee, S.; Roellig, T.L.; Hills, R.; Brock, D. (Hawaii Univ., Honolulu (USA) NASA, Ames Research Center, Moffett Field, CA (USA) Mullard Radio Astronomy Observatory, Cambridge (England) Joint Astronomy Centre, Hilo, HI (USA))

    1990-04-01

    The first submillimeter solar observations from the 15 m James Clerk Maxwell Telescope (JCMT) on Mauna Kea are reported. The JCMT submillimeter heterodyne receiver is used to observe the sun in 850 micron radiation. These are the first submillimeter observations of features on the size scale of the chromospheric supergranular network and of sunspots. A comparison is made between 850 micron images and calcium K line images of the chromospheric supergranular network in the quiet sun and in plage. Images of sunspots are given, noting that their 850 micron brightness is comparable to, or somewhat greater than, that of the quiet sun. 7 refs.

  2. Submillimeter observations of the sun from the James Clerk Maxwell Telescope

    Science.gov (United States)

    Lindsey, Charles A.; Yee, Selwyn; Roellig, Thomas L.; Hills, Richard; Brock, David

    1990-01-01

    The first submillimeter solar observations from the 15 m James Clerk Maxwell Telescope (JCMT) on Mauna Kea are reported. The JCMT submillimeter heterodyne receiver is used to observe the sun in 850 micron radiation. These are the first submillimeter observations of features on the size scale of the chromospheric supergranular network and of sunspots. A comparison is made between 850 micron images and calcium K line images of the chromospheric supergranular network in the quiet sun and in plage. Images of sunspots are given, noting that their 850 micron brightness is comparable to, or somewhat greater than, that of the quiet sun.

  3. Imaging doppler velocimeter with downward heterodyning in the optical domain

    Science.gov (United States)

    Reu, Phillip L; Hansche, Bruce D

    2013-05-21

    In a Doppler velocimeter, the incoming Doppler-shifted beams are heterodyned to reduce their frequencies into the bandwidth of a digital camera. This permits the digital camera to produce at every sampling interval a complete two-dimensional array of pixel values. This sequence of pixel value arrays provides a velocity image of the target.

  4. Faint Submillimeter Galaxies Behind Lensing Clusters

    Science.gov (United States)

    Hsu, Li-Yen; Lauchlan Cowie, Lennox; Barger, Amy J.; Desai, Vandana; Murphy, Eric J.

    2017-01-01

    Faint submillimeter galaxies are the major contributors to the submillimeter extragalactic background light and hence the dominant star-forming population in the dusty universe. Determining how much these galaxies overlap the optically selected samples is critical to fully account for the cosmic star formation history. Observations of massive cluster fields are the best way to explore this faint submillimeter population, thanks to gravitational lensing effects. We have been undertaking a lensing cluster survey with the SCUBA-2 camera on the James Clerk Maxwell Telescope to map nine galaxy clusters, including the northern five clusters in the HST Frontier Fields program. We have also been using the Submillimeter Array and the Very Large Array to determine the accurate positions of our detected sources. Our observations have discovered high-redshift dusty galaxies with far-infrared luminosities similar to that of the Milky Way or luminous infrared galaxies. Some of these galaxies are still undetected in deep optical and near-infrared images. These results suggest that a substantial amount of star formation in even the faint submillimeter population may be hidden from rest-frame optical surveys.

  5. Heterodyne Interferometer Angle Metrology

    Science.gov (United States)

    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.

  6. Compact heterodyne NEMS oscillator for sensing applications

    Science.gov (United States)

    Sansa, Marc; Gourlat, Guillaume; Jourdan, Guillaume; Gely, Marc; Villard, Patrick; Sicard, Gilles; Hentz, Sébastien

    2016-11-01

    We present a novel topology of heterodyne nanoelectromechanical self-oscillator, aimed at the dense integration of resonator arrays for sensing applications. This oscillator is based on an original measurement method, suitable for both open loop and closed loop operations, which simplifies current down-mixing set-ups. When implemented on-chip, it will allow the reduction of the size and power consumption of readout CMOS circuitry. This is today the limiting factor for the integration density of NEMS oscillators for real-life applications. Here we characterize this method in both open-loop and closed-loop, and evaluate its frequency stability.

  7. An ALMA Survey of Submillimeter Galaxies in the Extended Chandra Deep Field South : Source Catalog and Multiplicity

    NARCIS (Netherlands)

    Hodge, J.; Karim, A.; Smail, I.; Swinbank, A.; Walter, F.; Biggs, A.; Ivison, R.; Weiss, A.; Alexander, D.; Bertoldi, F.; Brandt, W.; Chapman, S.; Coppin, K.; Cox, P.; Danielson, A.; Dannerbauer, H.; De, Breuck C.; Decarli, R.; Edge, A.; Greve, T.; Knudsen, K.; Menten, K.; Rix, H.; Schinnerer, E.; Simpson, J.; Wardlow, J.; Werf, van der P.P.

    2013-01-01

    We present an Atacama Large Millimeter/submillimeter Array (ALMA) Cycle 0 survey of 126 submillimeter sources from the LABOCA ECDFS Submillimeter Survey (LESS). Our 870 {$μ$}m survey with ALMA (ALESS) has produced maps ~{}3{ imes} deeper and with a beam area ~{}200{ imes} smaller than the original

  8. Differential doppler heterodyning technique

    DEFF Research Database (Denmark)

    Lading, Lars

    1971-01-01

    Measuring velocity without disturbing the moving object is possible by use of the laser doppler heterodyning technique. Theoretical considerations on the doppler shift show that the antenna property of the photodetector can solve an apparent conflict between two different ways of calculating...... the detected doppler frequency. It is found that the doppler frequency for this particular setup is independent of the direction of detection. Investigations of the signal-to-noise ratio (SNR) show that the maximum SNR-considering the optical setup-is obtained by measuring the frequency difference between two...... doppler-shifted beams rather than by measuring the shift of a single beam by comparing it with a reference beam. Measurements seem to be in agreement with the theoretical consideration...

  9. Highspeed multiplexed heterodyne interferometry.

    Science.gov (United States)

    Isleif, Katharina-S; Gerberding, Oliver; Köhlenbeck, Sina; Sutton, Andrew; Sheard, Benjamin; Goßler, Stefan; Shaddock, Daniel; Heinzel, Gerhard; Danzmann, Karsten

    2014-10-06

    Digitally enhanced heterodyne interferometry is a metrology technique that uses pseudo-random noise codes for modulating the phase of the laser light. Multiple interferometric signals from the same beam path can thereby be isolated based on their propagation delay, allowing one to use advantageous optical layouts in comparison to classic laser interferometers. We present here a high speed version of this technique for measuring multiple targets spatially separated by only a few centimetres. This allows measurements of multiplexed signals using free beams, making the technique attractive for several applications requiring compact optical set-ups like for example space-based interferometers. In an experiment using a modulation and sampling rate of 1.25 GHz we are able to demonstrate multiplexing between targets only separated by 36 cm and we achieve a displacement measurement noise floor of up. Utilising an active clock jitter correction scheme we are also able to reduce this noise in a null measurement configuration by one order of magnitude.

  10. Submillimeter Continuum Observations of Comets

    Science.gov (United States)

    Jewitt, David

    1998-01-01

    The aim of this proposal was to study the submillimeter continuum emission from comets. The study was based mainly on the exploitation of the world's leading submillimeter telescope, the JCMT (James Clerk Maxwell Telescope) on Mauna Kea. Submillimeter wavelengths provide a unique view of cometary physics for one main reason. The cometary size distribution is such that the scattering cross-section is dominated by small dust grains, while the mass is dominated by the largest particles. Submillimeter continuum radiation samples cometary particles much larger than those sampled by more common observations at shorter (optical and infrared) wavelengths and therefore provides a nearly direct measure of the cometary dust mass.

  11. A Black Hole Mass-Variability Timescale Correlation at Submillimeter Wavelengths

    NARCIS (Netherlands)

    Bower, G.C.; Dexter, J.; Markoff, S.; Gurwell, M.A.; Rao, R.; McHardy, I.

    2015-01-01

    We analyze the light curves of 413 radio sources at submillimeter wavelengths using data from the Submillimeter Array calibrator database. The database includes more than 20,000 observations at 1.3 and 0.8 mm that span 13 years. We model the light curves as a damped random walk and determine a

  12. HERTZ, A Submillimeter Polarimeter

    Science.gov (United States)

    Schleuning, D. A.; Dowell, C. D.; Hildebrand, R. H.; Platt, S. R.; Novak, G.

    1997-03-01

    We describe a 32 pixel polarimeter, Hertz, for use at the Caltech Submillimeter Observatory. We present polarization maps of the Orion molecular cloud (OMC-1) at 350 \\mum (46 detections) and 450 \\mum (19 detections) with 3\\sigma or better statistical significance. The 350 \\mum polarization ranges from 1.4 to 6.8% with a median value of 3.3%. The position angles are fairly uniform across the souce at an angle of \\sim30 degrees (east of north). We describe the design and performance characteristics of the polarimeter and discuss systematic effects due to telescope and instrumental polarization, atmospheric fluctuations, and reference beam flux. (SECTION: Astronomical Instrumentation)

  13. Photon caliper to achieve submillimeter positioning accuracy

    Science.gov (United States)

    Gallagher, Kyle J.; Wong, Jennifer; Zhang, Junan

    2017-09-01

    The purpose of this study was to demonstrate the feasibility of using a commercial two-dimensional (2D) detector array with an inherent detector spacing of 5 mm to achieve submillimeter accuracy in localizing the radiation isocenter. This was accomplished by delivering the Vernier ‘dose’ caliper to a 2D detector array where the nominal scale was the 2D detector array and the non-nominal Vernier scale was the radiation dose strips produced by the high-definition (HD) multileaf collimators (MLCs) of the linear accelerator. Because the HD MLC sequence was similar to the picket fence test, we called this procedure the Vernier picket fence (VPF) test. We confirmed the accuracy of the VPF test by offsetting the HD MLC bank by known increments and comparing the known offset with the VPF test result. The VPF test was able to determine the known offset within 0.02 mm. We also cross-validated the accuracy of the VPF test in an evaluation of couch hysteresis. This was done by using both the VPF test and the ExacTrac optical tracking system to evaluate the couch position. We showed that the VPF test was in agreement with the ExacTrac optical tracking system within a root-mean-square value of 0.07 mm for both the lateral and longitudinal directions. In conclusion, we demonstrated the VPF test can determine the offset between a 2D detector array and the radiation isocenter with submillimeter accuracy. Until now, no method to locate the radiation isocenter using a 2D detector array has been able to achieve such accuracy.

  14. Simulations for membrane-based HEB mixers in array configuration for SHAHIRA

    Science.gov (United States)

    Baubert, Jean; Salez, Morvan; Merkel, Harald F.; Pons, Patrick; Delorme, Yan; Lecomte, Benoit

    2004-10-01

    We present in this paper the front-end design and the results of RF simulations, carried out with Microwave Studio (CST) and HFSS for SHAHIRA (Submillimeter Heterodyne Array for High-speed Radio Astronomy), a 4x4 heterodyne array at 2.5 THz and 4.7 THz. One can then observe 16 spatial positions at 2 frequencies. The design has been chosen to be quasi-optic, because of its simplicity, novelty and multi-pixels applicability. Pixels are made of Niobium Nitride HEB mixers with double-slot antennas, processed on 1 μm thick stress-less Si3N4/SiO2 membrane. The use of the membrane shows numerous advantages: for instance the use of the mixers at higher RF frequencies, a better power coupling efficiency or a solution for avoiding dielectric modes, losses and reflections. This work is supported by ESA and is a collaboration between LERMA, CHALMERS and LAAS. The Camera is expected to find applications, for SOFIA or CIDRE.

  15. Analysis on optical heterodyne frequency error of full-field heterodyne interferometer

    Science.gov (United States)

    Li, Yang; Zhang, Wenxi; Wu, Zhou; Lv, Xiaoyu; Kong, Xinxin; Guo, Xiaoli

    2017-06-01

    The full-field heterodyne interferometric measurement technology is beginning better applied by employing low frequency heterodyne acousto-optical modulators instead of complex electro-mechanical scanning devices. The optical element surface could be directly acquired by synchronously detecting the received signal phases of each pixel, because standard matrix detector as CCD and CMOS cameras could be used in heterodyne interferometer. Instead of the traditional four-step phase shifting phase calculating, Fourier spectral analysis method is used for phase extracting which brings lower sensitivity to sources of uncertainty and higher measurement accuracy. In this paper, two types of full-field heterodyne interferometer are described whose advantages and disadvantages are also specified. Heterodyne interferometer has to combine two different frequency beams to produce interference, which brings a variety of optical heterodyne frequency errors. Frequency mixing error and beat frequency error are two different kinds of inescapable heterodyne frequency errors. In this paper, the effects of frequency mixing error to surface measurement are derived. The relationship between the phase extraction accuracy and the errors are calculated. :: The tolerance of the extinction ratio of polarization splitting prism and the signal-to-noise ratio of stray light is given. The error of phase extraction by Fourier analysis that caused by beat frequency shifting is derived and calculated. We also propose an improved phase extraction method based on spectrum correction. An amplitude ratio spectrum correction algorithm with using Hanning window is used to correct the heterodyne signal phase extraction. The simulation results show that this method can effectively suppress the degradation of phase extracting caused by beat frequency error and reduce the measurement uncertainty of full-field heterodyne interferometer.

  16. Fast computation of the Narcissus reflection coefficient for the Herschel far-infrared/submillimeter-wave Cassegrain telescope

    Science.gov (United States)

    Lucke, Robert L.; Fischer, Jacqueline; Polegre, Arturo M.; Beintema, Douwe A.

    2005-10-01

    Placement of a scatter cone at the center of the secondary of a Cassegrain telescope greatly reduces Narcissus reflection. To calculate the remaining Narcissus reflection, a time-consuming physical optics code such as GRASP8 is often used to model the effects of reflection and diffraction. Fortunately, the Cassegrain geometry is sufficiently simple that a combination of theoretical analysis and Fourier propagation can yield rapid, accurate results at submillimeter wavelengths. We compare these results with those from GRASP8 for the heterodyne instrument for the far-infrared on the Herschel Space Observatory and confirm the effectiveness of the chosen scatter cone design.

  17. SUBMILLIMETER LIGHTCURVES OF ASTEROIDS V1.0

    Data.gov (United States)

    National Aeronautics and Space Administration — Submillimeter lightcurves of large asteroids Ceres, Davida, Io, Juno, Pallas, Vesta, and Victoria, observed at the Heinrich-Hertz Submillimeter Telescope from...

  18. Heterodyne displacement interferometer, insensitive for input polarization

    NARCIS (Netherlands)

    Meskers, A.J.H.; Spronck, J.W.; Munnig Schmidt, R.H.

    2014-01-01

    Periodic nonlinearity (PNL) in displacement interferometers is a systematic error source that limits measurement accuracy. The PNL of coaxial heterodyne interferometers is highly influenced by the polarization state and orientation of the source frequencies. In this Letter, we investigate this error

  19. Laser Metrology Heterodyne Phase-Locked Loop

    Science.gov (United States)

    Loya, Frank; Halverson, Peter

    2009-01-01

    A method reduces sensitivity to noise in a signal from a laser heterodyne interferometer. The phase-locked loop (PLL) removes glitches that occur in a zero-crossing detector s output [that can happen if the signal-to-noise ratio (SNR) of the heterodyne signal is low] by the use of an internal oscillator that produces a square-wave signal at a frequency that is inherently close to the heterodyne frequency. It also contains phase-locking circuits that lock the phase of the oscillator to the output of the zero-crossing detector. Because the PLL output is an oscillator signal, it is glitch-free. This enables the ability to make accurate phase measurements in spite of low SNR, creates an immunity to phase error caused by shifts in the heterodyne frequency (i.e. if the target moves causing Doppler shift), and maintains a valid phase even when the signal drops out for brief periods of time, such as when the laser is blocked by a stray object.

  20. CLUMPY AND EXTENDED STARBURSTS IN THE BRIGHTEST UNLENSED SUBMILLIMETER GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Iono, Daisuke; Hatsukade, Bunyo; Kawabe, Ryohei; Matsuda, Yuichi; Nakanishi, Kouichiro [National Astronomical Observatory of Japan, National Institutes of Natural Sciences, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Yun, Min S.; Wilson, Grant [University of Massachusetts, Department of Astronomy, 710 North Pleasant Street, Amherst, MA 01003 (United States); Aretxaga, Itziar; Hughes, David [Instituto Nacional de Astrofisica, Optica y Electronica (INAOE), Luis Enrique Erro 1, Sta. Ma. Tonantzintla, Puebla (Mexico); Ikarashi, Soh [Kapteyn Astronomical Institute, University of Groningen, P.O. Box 800, 9700AV Groningen (Netherlands); Izumi, Takuma; Kohno, Kotaro; Tamura, Yoichi; Umehata, Hideki [Institute of Astronomy, The University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan); Lee, Minju; Saito, Toshiki [Department of Astronomy, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 133-0033 (Japan); Ueda, Junko [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Michiyama, Tomonari; Ando, Misaki, E-mail: d.iono@nao.ac.jp [SOKENDAI (The Graduate University for Advanced Studies), 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)

    2016-09-20

    The central structure in three of the brightest unlensed z = 3–4 submillimeter galaxies is investigated through 0.″015–0.″05 (120–360 pc) 860 μ m continuum images obtained using the Atacama Large Millimeter/submillimeter Array (ALMA). The distribution in the central kiloparsec in AzTEC1 and AzTEC8 is extremely complex, and they are composed of multiple ∼200 pc clumps. AzTEC4 consists of two sources that are separated by ∼1.5 kpc, indicating a mid-stage merger. The peak star formation rate densities in the central clumps are ∼300–3000 M {sub ⊙} yr{sup −1} kpc{sup −2}, suggesting regions with extreme star formation near the Eddington limit. By comparing the flux obtained by ALMA and Submillimeter Array, we find that 68%–90% of the emission is extended (≳1 kpc) in AzTEC4 and 8. For AzTEC1, we identify at least 11 additional compact (∼200 pc) clumps in the extended 3–4 kpc region. Overall, the data presented here suggest that the luminosity surface densities observed at ≲150 pc scales are roughly similar to that observed in local ULIRGs, as in the eastern nucleus of Arp 220. Between 10% and 30% of the 860 μ m continuum is concentrated in clumpy structures in the central kiloparsec, while the remaining flux is distributed over ≳1 kpc regions, some of which could also be clumpy. These sources can be explained by a rapid inflow of gas such as a merger of gas-rich galaxies, surrounded by extended and clumpy starbursts. However, the cold mode accretion model is not ruled out.

  1. Ozone height profiles using laser heterodyne radiometer

    Science.gov (United States)

    Jain, S. L.

    1994-01-01

    The monitoring of vertical profiles of ozone and related minor constituents in the atmosphere are of great significance to understanding the complex interaction between atmospheric dynamics, chemistry and radiation budget. An ultra high spectral resolution tunable CO2 laser heterodyne radiometer has been designed, developed and set up at the National Physical Laboratory, New Delhi to obtain vertical profiles of various minor constituents the characteristic absorption lines in 9 to 11 micron spectral range. Due to its high spectral resolution the lines can be resolved completely and data obtained are inverted to get vertical profiles using an inversion technique developed by the author. In the present communication the salient features of the laser heterodyne system and the results obtained are discussed in detail.

  2. Heterodyne high-spectral-resolution lidar.

    Science.gov (United States)

    Chouza, Fernando; Witschas, Benjamin; Reitebuch, Oliver

    2017-10-10

    In this work, a novel lidar technique to perform high-spectral-resolution measurements of the atmospheric backscatter is discussed and the first results are presented. The proposed method, which relies on a heterodyne detection receiver, allows us not only to separate the molecular and the aerosol component of the atmospheric backscatter, but also to investigate the spectral shape of the Rayleigh-Brillouin line. As in the case of the direct-detection high-spectral-resolution lidars, the separation of the different scattering processes would allow an independent system calibration and aerosol extinction measurements. The proposed retrieval technique was successfully tested on the Deutsches Zentrum für Luft- und Raumfahrt airborne Doppler wind lidar system with measurements conducted during different measurement campaigns and under different atmospheric conditions. In light of these results, further ideas for the implementation of a dedicated heterodyne high-spectral-resolution lidar are discussed.

  3. Temporal heterodyne shearing speckle pattern interferometry

    Science.gov (United States)

    Wang, Xu; Gao, Zhan; Qin, Jie; Zhang, Xiaoqiong; Yang, Shanwei

    2017-06-01

    Shearing speckle pattern interferometry is a full-field speckle interferometric technique used to determine surface displacement derivatives. In this paper, a new measurement system of real-time heterodyne shearography interferometry is presented. This system combined with heterodyne measurement, shearography interferometry and time domain signal processing technology can dynamically detect the out-of-plane displacement gradient. The principles and system arrangement are described. Using the Jones matrix, the mathematical expression of light intensity distribution passing through this system is deduced. A preliminary experiment was performed to demonstrate the performance of this new device, and simulations were conducted using the finite element method. Comparison of results shows that quantitative measurement of the displacement derivative has been achieved.

  4. Active Millimeter and Submillimeter Sensing Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The workshop will have three main objectives. The first will be to inventory the signatures and measurements that are desirable to make using submillimeter active...

  5. SHIMS -- A Spatial Heterodyne Interferometer for Methane Sounding Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This project develops the Spatial Heterodyne Interferometer for Methane Sounding (SHIMS), a lightweight, compact, robust spectrometer system for remote sensing of...

  6. SMA Submillimeter Observations of HL Tau: Revealing a Compact Molecular Outflow

    Science.gov (United States)

    Lumbreras, Alba M.; Zapata, Luis A.

    2014-04-01

    We present archival high angular resolution (~2'') 12CO(3-2) line and continuum submillimeter observations of the young stellar object HL Tau made with the Submillimeter Array. The 12CO(3-2) line observations reveal the presence of a compact and wide opening angle bipolar outflow with a northeast to southwest orientation (P.A. = 50°) that is associated with the optical and infrared jet emanating from HL Tau with a similar orientation. On the other hand, the 850 μm continuum emission observations exhibit a strong and compact source in the position of HL Tau that has a spatial size of ~200 × 70 AU with a P.A. = 145° and a dust mass of around 0.1 M ⊙. These physical parameters are in agreement with values obtained recently from millimeter observations. This submillimeter source is therefore related to the disk surrounding HL Tau.

  7. SMA submillimeter observations of HL Tau: revealing a compact molecular outflow

    Energy Technology Data Exchange (ETDEWEB)

    Lumbreras, Alba M.; Zapata, Luis A. [Centro de Radioastronomía y Astrofísica, UNAM, Morelia (Mexico)

    2014-04-01

    We present archival high angular resolution (∼2'') {sup 12}CO(3-2) line and continuum submillimeter observations of the young stellar object HL Tau made with the Submillimeter Array. The {sup 12}CO(3-2) line observations reveal the presence of a compact and wide opening angle bipolar outflow with a northeast to southwest orientation (P.A. = 50°) that is associated with the optical and infrared jet emanating from HL Tau with a similar orientation. On the other hand, the 850 μm continuum emission observations exhibit a strong and compact source in the position of HL Tau that has a spatial size of ∼200 × 70 AU with a P.A. = 145° and a dust mass of around 0.1 M {sub ☉}. These physical parameters are in agreement with values obtained recently from millimeter observations. This submillimeter source is therefore related to the disk surrounding HL Tau.

  8. The Hawaii SCUBA-2 Lensing Cluster Survey: Are Low-luminosity Submillimeter Galaxies Detected in the Rest-frame UV?

    Science.gov (United States)

    Hsu, Li-Yen; Cowie, Lennox L.; Barger, Amy J.; Wang, Wei-Hao

    2017-12-01

    In this third paper of the Hawaii SCUBA-2 Lensing Cluster Survey series, we present Submillimeter Array (SMA) detections of six intrinsically faint 850 μm sources detected in SCUBA-2 images of the lensing cluster fields, A1689, A2390, A370, MACS J0717.5+3745, and MACS J1423.8+2404. Two of the SCUBA-2 sources split into doublets, yielding a total of eight SMA detections. The intrinsic 870 μm flux densities of these submillimeter galaxies (SMGs) are ∼1 mJy. Five of the eight SMGs are not detected in optical or near-infrared (NIR) images. The NIR-to-submillimeter flux ratios of these faint SMGs suggest that most of them are extremely dusty and/or are at very high redshifts. By combining these SMGs and several other samples from the literature, we find a bimodal distribution for the faint sources in the space of submillimeter flux versus NIR-to-submillimeter flux ratio. While most of the SMA-detected lensed sources are very obscured, the other SMGs with similar flux densities are mostly bright in the NIR. Future Atacama Large Millimeter/submillimeter Array observations of a large sample of SCUBA-2 sources in cluster fields will allow us to decide whether or not the bimodality we observe here really exists.

  9. Demonstration of Submillimeter Astrophysics Technology at Caltech Submillimeter Observatory Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The following are the objectives of this project:(1) Demonstration of 1600-element Kinetic Inductance Detector (KID) imaging array operating at 350 micron with near...

  10. Detection of Circular Polarization from Sagittarius A* at Submillimeter Wavelengths

    Science.gov (United States)

    Munoz, Diego; Marrone, D.; Moran, J.

    2009-05-01

    We report the detection of circularly polarized (CP) emission from the compact radio source Sagittarius A* at a level of 1.5% at a frequency of 235 GHz (1.4 mm). Sgr A* is associated with the supermassive black hole (SMBH) in the Galactic Center. The observations, taken with the Submillimeter Array (SMA) on 03/31/2007, also show a linearly polarized (LP) component of 7%. The snr of our detection of CP is about 14. Before our measurements, CP had only been detected at frequencies between 1.4 and 15 GHz (21 and 2 cm) at levels Faraday rotation in the stationary screen (constant RM)acts on a time variable background source. A cold, optically thin plasma screen cannot be responsible for both a constant RM and Faraday conversion from LP to CP, therefore the observed amounts of CP are likely to be originated close to the central source. Sgr A* shows a flat-to-inverted radio spectrum and a submillimeter excess referred to as the "submillimeter bump". This excess it thought to come from the closest regions to the SMBH. In such a scenario, millimeter wavelength data is associated with regions in which the material is likely to be relativistic and the magnetic field ordered. We have carried out polarized radiative transfer calculations exploring different combinations of ordered and stochastic magnetic fields looking for a favored scenario that can explain the apparent constant increase of CP with frequency as well as the sudden jump in LP between 40 and 80 GHz.

  11. Terahertz heterodyne technology for astronomy and planetary science

    NARCIS (Netherlands)

    Wild, Wolfgang

    2007-01-01

    Heterodyne detection techniques play an important role in high-resolution spectroscopy in astronomy and planetary science. In particular, heterodyne technology in the Terahertz range has rapidly evolved in recent years. Cryogenically cooled receivers approaching quantum-limited sensitivity have been

  12. Full-field heterodyne dynamic interferometry based on hertz-level low differential-frequency acousto-optic frequency shifter

    Science.gov (United States)

    Wu, Zhou; Zhang, Wenxi; Xiangli, Bin; Kong, Xinxin

    2017-06-01

    High precision measurement of optical elements with long focal length is affected by vibration, airflow and other environmental factors due to the long cavity length, which has been difficulty and hot issue in optical machining and detection. In order to overcome the difficulties of high precision measurement of optical elements with long focal length, the paper proposes a full-field heterodyne interferometric measurement technique that could effectively suppress the environmental interference. In the early related research, a series of Hertz-level high-stability, low-differential frequency acousto-optic frequency shifters were successfully developed, which could be applied to heterodyne interferometry, instead of traditional phase-shifting intererometry. On this basis, a full-field heterodyne interference measurement system is developed, using array detector with conventional frame rate for full-field detection, to solve the problem of different optical paths of reference light and measuring light in dynamic interferometers. It could effectively suppress the vibration, noise, airflow and other factors, and thus significantly improve measurement accuracy and environmental adaptability. In typical environment with vibration and airflow, our measurement system can achieve technical indicators as follows: surface measurement accuracy is better than λ/1000 and repeated measurement accuracy is better than 5λ/10000. Thereby the new full-field heterodyne interferometry could be applied to dynamic measurement of large-diameter optical components and systems quality inspection, system installation correction, on-line measurement and other areas.

  13. An alma survey of submillimeter galaxies in the extended Chandra deep field-south: The agn fraction and X-ray properties of submillimeter galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Wang, S. X.; Brandt, W. N.; Luo, B. [Department of Astronomy and Astrophysics, 525 Davey Lab, The Pennsylvania State University, University Park, PA 16802 (United States); Smail, I.; Alexander, D. M.; Danielson, A. L. R.; Karim, A.; Simpson, J. M.; Swinbank, A. M. [Institute for Computational Cosmology, Durham University, South Road, Durham DH1 3LE (United Kingdom); Hodge, J. A.; Walter, F. [Max-Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); Lehmer, B. D. [The Johns Hopkins University, Homewood Campus, Baltimore, MD 21218 (United States); Wardlow, J. L. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Xue, Y. Q. [Key Laboratory for Research in Galaxies and Cosmology, Center for Astrophysics, Department of Astronomy, University of Science and Technology of China, Chinese Academy of Sciences, Hefei, Anhui 230026 (China); Chapman, S. C. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Coppin, K. E. K. [Centre for Astrophysics, Science and Technology Research Institute, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom); Dannerbauer, H. [Universität Wien, Institute für Astrophysik, Türkenschanzstraße 17, 1180 Wien (Austria); De Breuck, C. [European Southern Observatory, Karl-Schwarzschild Straße 2, D-85748 Garching (Germany); Menten, K. M. [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Van der Werf, P., E-mail: xxw131@psu.edu, E-mail: niel@astro.psu.edu [Leiden Observatory, Leiden University, P.O. Box 9513, NL-2300 RA Leiden (Netherlands)

    2013-12-01

    The large gas and dust reservoirs of submillimeter galaxies (SMGs) could potentially provide ample fuel to trigger an active galactic nucleus (AGN), but previous studies of the AGN fraction in SMGs have been controversial largely due to the inhomogeneity and limited angular resolution of the available submillimeter surveys. Here we set improved constraints on the AGN fraction and X-ray properties of the SMGs with Atacama Large Millimeter/submillimeter Array (ALMA) and Chandra observations in the Extended Chandra Deep Field-South (E-CDF-S). This study is the first among similar works to have unambiguously identified the X-ray counterparts of SMGs; this is accomplished using the fully submillimeter-identified, statistically reliable SMG catalog with 99 SMGs from the ALMA LABOCA E-CDF-S Submillimeter Survey. We found 10 X-ray sources associated with SMGs (median redshift z = 2.3), of which eight were identified as AGNs using several techniques that enable cross-checking. The other two X-ray detected SMGs have levels of X-ray emission that can be plausibly explained by their star formation activity. Six of the eight SMG-AGNs are moderately/highly absorbed, with N {sub H} > 10{sup 23} cm{sup –2}. An analysis of the AGN fraction, taking into account the spatial variation of X-ray sensitivity, yields an AGN fraction of 17{sub −6}{sup +16}% for AGNs with rest-frame 0.5-8 keV absorption-corrected luminosity ≥7.8 × 10{sup 42} erg s{sup –1}; we provide estimated AGN fractions as a function of X-ray flux and luminosity. ALMA's high angular resolution also enables direct X-ray stacking at the precise positions of SMGs for the first time, and we found four potential SMG-AGNs in our stacking sample.

  14. Superconducting Bolometer Array Architectures

    Science.gov (United States)

    Benford, Dominic J.; Chervenak, James A.; Irwin, Kent D.; Moseley, S. H., Jr.; Shafer, Richard A.; Staguhn, Johannes G.; Wollack, Ed

    2003-02-01

    The next generation of far-infrared and submillimeter instruments require large arrays of detectors containing thousands of elements. These arrays will necessarily be multiplexed, and superconducting bolometer arrays are the most promising present prospect for these detectors. We discuss our current research into superconducting bolometer array technologies, which has recently resulted in the first multiplexed detections of submillimeter light and the first multiplexed astronomical observations. Prototype arrays containing 512 pixels are in production using the Pop-Up Detector (PUD) architecture, which can be extended easily to 1000 pixel arrays. Planar arrays of close-packed bolometers are being developed for the GBT and for future space missions. For certain applications, such as a slewed far-infrared sky survey, feedhorn-coupling of a large sparsely-filled array of bolometers is desirable, and is being developed using photolithographic feedhorn arrays. Individual detectors have achieved a Noise Equivalent Power (NEP) of ~10-17 W/√Hz at 300mK, but several orders of magnitude improvement are required and can be reached with existing technology. The testing of such ultralow-background detectors will prove difficult, as this requires optical loading of below 1fW. Antenna-coupled bolometer designs have advantages for large format array designs at low powers due to their mode selectivity. We also present a design and preliminary results for an enhanced-dynamic-range transition edge sensor suitable for broadband ultralow-background detectors.

  15. High-Sensitivity AGN Polarimetry at Sub-Millimeter Wavelengths

    Directory of Open Access Journals (Sweden)

    Ivan Martí-Vidal

    2017-10-01

    Full Text Available The innermost regions of radio loud Active Galactic Nuclei (AGN jets are heavily affected by synchrotron self-absorption, due to the strong magnetic fields and high particle densities in these extreme zones. The only way to overcome this absorption is to observe at sub-millimeter wavelengths, although polarimetric observations at such frequencies have so far been limited by sensitivity and calibration accuracy. However, new generation instruments such as the Atacama Large mm/sub-mm Array (ALMA overcome these limitations and are starting to deliver revolutionary results in the observational studies of AGN polarimetry. Here we present an overview of our state-of-the-art interferometric mm/sub-mm polarization observations of AGN jets with ALMA (in particular, the gravitationally-lensed sources PKS 1830−211 and B0218+359, which allow us to probe the magneto-ionic conditions at the regions closest to the central black holes.

  16. The SCUBA-2 Cosmology Legacy Survey: ALMA Resolves the Bright-end of the Sub-millimeter Number Counts

    NARCIS (Netherlands)

    Simpson, J. M.; Smail, Ian; Swinbank, A. M.; Chapman, S. C.; Geach, J. E.; Ivison, R. J.; Thomson, A. P.; Aretxaga, I.; Blain, A. W.; Cowley, W. I.; Chen, Chian-Chou; Coppin, K. E. K.; Dunlop, J. S.; Edge, A. C.; Farrah, D.; Ibar, E.; Karim, A.; Knudsen, K. K.; Meijerink, R.; Michałowski, M. J.; Scott, D.; Spaans, M.; van der Werf, P. P.

    We present high-resolution 870 μm Atacama Large Millimeter/sub-millimeter Array (ALMA) continuum maps of 30 bright sub-millimeter sources in the UKIDSS UDS field. These sources are selected from deep, 1 degree2 850 μm maps from the SCUBA-2 Cosmology Legacy Survey, and are representative of the

  17. Spatial Heterodyne Spectrometer for Aviation Hazard Detection Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Physical Sciences Inc (PSI) proposes the development of a longwave infrared (LWIR) imaging spatial heterodyne spectrometer (I-SHS) for standoff detection of clear...

  18. Background free CARS imaging by phase sensitive heterodyne CARS

    OpenAIRE

    Jurna, M.; Korterik, Jeroen P.; Otto, Cornelis; Herek, Jennifer Lynn; Offerhaus, Herman L.

    2008-01-01

    In this article we show that heterodyne CARS, based on a controlled and stable phase-preserving chain, can be used to measure amplitude and phase information of molecular vibration modes. The technique is validated by a comparison of the imaginary part of the heterodyne CARS spectrum to the spontaneous Raman spectrum of polyethylene. The detection of the phase allows for rejection of the non-resonant background from the data. The resulting improvement of the signal to noise ratio is shown by ...

  19. Four-state discrimination scheme beyond the heterodyne limit

    DEFF Research Database (Denmark)

    Muller, C. R.; Castaneda, Mario A. Usuga; Wittmann, C.

    2012-01-01

    We propose and experimentally demonstrate a hybrid discrimination scheme for the quadrature phase shift keying protocol, which outperforms heterodyne detection for any signal power. The discrimination is composed of a quadrature measurement, feed forward and photon detection.......We propose and experimentally demonstrate a hybrid discrimination scheme for the quadrature phase shift keying protocol, which outperforms heterodyne detection for any signal power. The discrimination is composed of a quadrature measurement, feed forward and photon detection....

  20. Optical sound wave recording by digital holography with heterodyne technique

    Science.gov (United States)

    Quan, Xiangyu; Rajput, Sudheesh; Nitta, Kouichi; Matoba, Osamu; Awatsuji, Yasuhiro

    2017-06-01

    A visualization technique of sound wave propagation using digital holography with heterodyne technique is presented. In the proposed method, the frequency of the interference pattern in an off-axis digital holography is down converted into the detectable frequency in an image sensor operated at the video frame rate by using the heterodyne interferometer. We present the principle of the recording technique and experimental results are described.

  1. The Submillimeter Array – current status and future plans

    Science.gov (United States)

    Blundell, Raymond

    2018-01-01

    The current SMA receiver systems were designed in the mid-1990s and have been operating for more than fifteen years. With regular upgrades to receivers, deployment of the SWARM correlator, expansion of the IF signal transport bandwidth via improvements to the analog IF signal processing hardware, and many other enhancements, the SMA currently greatly outperforms its original specifications in terms of sensitivity, instantaneous bandwidth, and availability of observing modes such as full-Stokes polarization and dual frequency operation.We have recently started to implement a three-year instrument upgrade plan, which we are calling the wSMA. The wSMA will offer even wider bandwidth operation than the current SMA and improved sensitivity. The major subsystems that will form the wSMA include significantly improved, dual polarization receiver cartridges housed in a new cryostat; local oscillator units incorporating modern mm-wave technology; an upgraded signal transmission system; and a further expansion of the SWARM correlator. The cryostat will be cooled by a low-maintenance pulse-tube cryocooler. Two dual-polarization receiver cartridges will cover approximately the same sky frequencies as the current receiver sets; the low-band receiver will be fed by an LO unit covering 210-270 GHz, and the high-band receiver will be fed by an LO covering 280-360 GHz. With a receiver IF band of 4-20 GHz, this will enable continuous sky frequency coverage from 190 GHz to 380 GHz.Details of the upgrade plans will be presented together with a discussion of scientific opportunities afforded by this upgrade, which, once implemented, will enable the SMA to continue to produce the highest quality science throughout the next decade.

  2. Faster processing of multiple spatially-heterodyned direct to digital holograms

    Science.gov (United States)

    Hanson, Gregory R [Clinton, TN; Bingham, Philip R [Knoxville, TN

    2008-09-09

    Systems and methods are described for faster processing of multiple spatially-heterodyned direct to digital holograms. A method includes of obtaining multiple spatially-heterodyned holograms, includes: digitally recording a first spatially-heterodyned hologram including spatial heterodyne fringes for Fourier analysis; digitally recording a second spatially-heterodyned hologram including spatial heterodyne fringes for Fourier analysis; Fourier analyzing the recorded first spatially-heterodyned hologram by shifting a first original origin of the recorded first spatially-heterodyned hologram including spatial heterodyne fringes in Fourier space to sit on top of a spatial-heterodyne carrier frequency defined as a first angle between a first reference beam and a first object beam; applying a first digital filter to cut off signals around the first original origin and performing an inverse Fourier transform on the result; Fourier analyzing the recorded second spatially-heterodyned hologram by shifting a second original origin of the recorded second spatially-heterodyned hologram including spatial heterodyne fringes in Fourier space to sit on top of a spatial-heterodyne carrier frequency defined as a second angle between a second reference beam and a second object beam; and applying a second digital filter to cut off signals around the second original origin and performing an inverse Fourier transform on the result, wherein digitally recording the first spatially-heterodyned hologram is completed before digitally recording the second spatially-heterodyned hologram and a single digital image includes both the first spatially-heterodyned hologram and the second spatially-heterodyned hologram.

  3. Faster processing of multiple spatially-heterodyned direct to digital holograms

    Science.gov (United States)

    Hanson, Gregory R.; Bingham, Philip R.

    2006-10-03

    Systems and methods are described for faster processing of multiple spatially-heterodyned direct to digital holograms. A method includes of obtaining multiple spatially-heterodyned holograms, includes: digitally recording a first spatially-heterodyned hologram including spatial heterodyne fringes for Fourier analysis; digitally recording a second spatially-heterodyned hologram including spatial heterodyne fringes for Fourier analysis; Fourier analyzing the recorded first spatially-heterodyned hologram by shifting a first original origin of the recorded first spatially-heterodyned hologram including spatial heterodyne fringes in Fourier space to sit on top of a spatial-heterodyne carrier frequency defined as a first angle between a first reference beam and a first, object beam; applying a first digital filter to cut off signals around the first original origin and performing an inverse Fourier transform on the result; Fourier analyzing the recorded second spatially-heterodyned hologram by shifting a second original origin of the recorded second spatially-heterodyned hologram including spatial heterodyne fringes in Fourier space to sit on top of a spatial-heterodyne carrier frequency defined as a second angle between a second reference beam and a second object beam; and applying a second digital filter to cut off signals around the second original origin and performing an inverse Fourier transform on the result, wherein digitally recording the first spatially-heterodyned hologram is completed before digitally recording the second spatially-heterodyned hologram and a single digital image includes both the first spatially-heterodyned hologram and the second spatially-heterodyned hologram.

  4. Diamond Heat-Spreader for Submillimeter-Wave Frequency Multipliers

    Science.gov (United States)

    Lin, Robert H.; Schlecht, Erich T.; Chattopadhyay, Goutam; Gill, John J.; Mehdi, Imran; Siegel, Peter H.; Ward, John S.; Lee, Choonsup; Thomas, Bertrand C.; Maestrini, Alain

    2010-01-01

    The planar GaAs Shottky diode frequency multiplier is a critical technology for the local oscillator (LO) for submillimeter- wave heterodyne receivers due to low mass, tenability, long lifetime, and room-temperature operation. The use of a W-band (75-100 GHz) power amplifier followed by a frequency multiplier is the most common for submillimeter-wave sources. Its greatest challenge is to provide enough input power to the LO for instruments onboard future planetary missions. Recently, JPL produced 800 mW at 92.5 GHz by combining four MMICs in parallel in a balanced configuration. As more power at W-band is available to the multipliers, their power-handling capability be comes more important. High operating temperatures can lead to degradation of conversion efficiency or catastrophic failure. The goal of this innovation is to reduce the thermal resistance by attaching diamond film as a heat-spreader on the backside of multipliers to improve their power-handling capability. Polycrystalline diamond is deposited by hot-filament chemical vapor deposition (CVD). This diamond film acts as a heat-spreader to both the existing 250- and 300-GHz triplers, and has a high thermal conductivity (1,000-1,200 W/mK). It is approximately 2.5 times greater than copper (401 W/mK) and 20 times greater than GaAs (46 W/mK). It is an electrical insulator (resistivity approx. equals 10(exp 15) Ohms-cm), and has a low relative dielectric constant of 5.7. Diamond heat-spreaders reduce by at least 200 C at 250 mW of input power, compared to the tripler without diamond, according to thermal simulation. This superior thermal management provides a 100-percent increase in power-handling capability. For example, with this innovation, 40-mW output power has been achieved from a 250-GHz tripler at 350-mW input power, while the previous triplers, without diamond, suffered catastrophic failures. This breakthrough provides a stepping-stone for frequency multipliers-based LO up to 3 THz. The future work

  5. Submillimeter solar images from the JCMT

    Energy Technology Data Exchange (ETDEWEB)

    Kopp, G.; Lindsey, C.

    1992-01-01

    We present nearly full-disk, diffraction-limited solar images made at 350 and 850 [mu]m and at 1.3 mm from the 15 m James Clerk Maxwell Telescope on Mauna Kea. These wavelengths sample the thermal structure of the solar chromosphere at altitude from 500 to about 1500 km, providing a height-dependent diagnostic of the atmosphere. Filament channels and neutral lines are apparent in the submillimeter images, although filaments themselves are not clearly visible. The submillimeter images show plage approximately 20% brigher than the surrounding quiet Sun, while sunspot intensities are comparable to the quiet Sun. Circumfacules,' dark are similar to those seen in Ca 8542; comparison with Ca H and K may give estimates of the temperature and filing factor of the hot gas present in these probably bifurcated regions.

  6. The millimeter and submillimeter spectrum of CF(+)

    Science.gov (United States)

    Plummer, G. M.; Anderson, T.; Herbst, E.; De Lucia, F. C.

    1986-01-01

    The application of a recently described technique for producing significantly enhanced concentrations of molecular ions for spectroscopic study to the detection and measurement of the millimeter and submillimeter wave spectrum of CF(+) is reported. The experimental procedure is discussed, and the measured absorption frequencies are shown and compared with those calculated from spectral constants. These constants are given together with those from the infrared spectrum by Kawaguchi and Hirota (1985).

  7. Status of MUSIC, the MUltiwavelength Sub/millimeter Inductance Camera

    Science.gov (United States)

    Golwala, Sunil R.; Bockstiegel, Clint; Brugger, Spencer; Czakon, Nicole G.; Day, Peter K.; Downes, Thomas P.; Duan, Ran; Gao, Jiansong; Gill, Amandeep K.; Glenn, Jason; Hollister, Matthew I.; LeDuc, Henry G.; Maloney, Philip R.; Mazin, Benjamin A.; McHugh, Sean G.; Miller, David; Noroozian, Omid; Nguyen, Hien T.; Sayers, Jack; Schlaerth, James A.; Siegel, Seth; Vayonakis, Anastasios K.; Wilson, Philip R.; Zmuidzinas, Jonas

    2012-09-01

    We present the status of MUSIC, the MUltiwavelength Sub/millimeter Inductance Camera, a new instrument for the Caltech Submillimeter Observatory. MUSIC is designed to have a 14', diffraction-limited field-of-view instrumented with 2304 detectors in 576 spatial pixels and four spectral bands at 0.87, 1.04, 1.33, and 1.98 mm. MUSIC will be used to study dusty star-forming galaxies, galaxy clusters via the Sunyaev-Zeldovich effect, and star formation in our own and nearby galaxies. MUSIC uses broadband superconducting phased-array slot-dipole antennas to form beams, lumpedelement on-chip bandpass filters to define spectral bands, and microwave kinetic inductance detectors to sense incoming light. The focal plane is fabricated in 8 tiles consisting of 72 spatial pixels each. It is coupled to the telescope via an ambient-temperature ellipsoidal mirror and a cold reimaging lens. A cold Lyot stop sits at the image of the primary mirror formed by the ellipsoidal mirror. Dielectric and metal-mesh filters are used to block thermal infrared and out-ofband radiation. The instrument uses a pulse tube cooler and 3He/ 3He/4He closed-cycle cooler to cool the focal plane to below 250 mK. A multilayer shield attenuates Earth's magnetic field. Each focal plane tile is read out by a single pair of coaxes and a HEMT amplifier. The readout system consists of 16 copies of custom-designed ADC/DAC and IF boards coupled to the CASPER ROACH platform. We focus on recent updates on the instrument design and results from the commissioning of the full camera in 2012.

  8. The Status of MUSIC: A Multicolor Sub/millimeter MKID Instrument

    Science.gov (United States)

    Schlaerth, J. A.; Czakon, N. G.; Day, P. K.; Downes, T. P.; Duan, R.; Glenn, J.; Golwala, S. R.; Hollister, M. I.; LeDuc, H. G.; Maloney, P. R.; Mazin, B. A.; Nguyen, H. T.; Noroozian, O.; Sayers, J.; Siegel, S.; Zmuidzinas, J.

    2012-05-01

    We report on the recent progress of the Multicolor Submillimeter (kinetic) Inductance Camera, or MUSIC. MUSIC will use antenna-coupled Microwave Kinetic Inductance Detectors to observe in four colors (150 GHz, 230 GHz, 290 GHz and 350 GHz) with 2304 detectors, 576 per band, at the Caltech Submillimeter Observatory. It will deploy in 2012. Here we provide an overview of the instrument, focusing on the array design. We have also used a pathfinder demonstration instrument, DemoCam, to identify problems in advance of the deployment of MUSIC. In particular, we identified two major limiters of our sensitivity: out-of-band light directly coupling to the detectors (i.e. not through the antenna), effectively an excess load, and a large 1/f contribution from our amplifiers and electronics. We discuss the steps taken to mitigate these effects to reach background-limited performance (BLIP) in observation.

  9. CHAMP + : A powerful array receiver for APEX

    NARCIS (Netherlands)

    Kasemann, C.; Güsten, R.; Heyminck, S.; Klein, B.; Klein, T.; Philipp, S. D.; Korn, A.; Schneider, G.; Henseler, A.; Baryshev, A.; Klapwijk, T. M.

    2006-01-01

    CHAMP +, a dual-color 2 × 7 element heterodyne array for operation in the 450 μm and 350 μm atmospheric windows is under development. The instrument, which is currently undergoing final evaluation in the laboratories, will be deployed for commissioning at the APEX telescope in August this year. With

  10. CHAMP+ : A powerful array receiver for APEX

    NARCIS (Netherlands)

    Kasemann, C.; Güsten, R.; Heyminck, S.; Klein, B.; Klein, T.; Philipp, S.D.; Korn, A.; Schneider, G.; Henseler, A.; Baryshev, A.; Klapwijk, T.M.

    2006-01-01

    CHAMP+, a dual-color 2 × 7 element heterodyne array for operation in the 450 ?m and 350 ?m atmospheric windows is under development. The instrument, which is currently undergoing final evaluation in the laboratories, will be deployed for commissioning at the APEX telescope in August this year. With

  11. Broadband Infrared Heterodyne Spectrometer: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Stevens, C G; Cunningham, C T; Tringe, J W

    2010-12-16

    This report summarizes the most important results of our effort to develop a new class of infrared spectrometers based on a novel broadband heterodyne design. Our results indicate that this approach could lead to a near-room temperature operation with performance limited only by quantum noise carried by the incoming signal. Using a model quantum-well infrared photodetector (QWIP), we demonstrated key performance features of our approach. For example, we directly measured the beat frequency signal generated by superimposing local oscillator (LO) light of one frequency and signal light of another through a spectrograph, by injecting the LO light at a laterally displaced input location. In parallel with the development of this novel spectrometer, we modeled a new approach to reducing detector volume though plasmonic resonance effects. Since dark current scales directly with detector volume, this ''photon compression'' can directly lead to lower currents. Our calculations indicate that dark current can be reduced by up to two orders of magnitude in an optimized ''superlens'' structure. Taken together, our spectrometer and dark current reduction strategies provide a promising path toward room temperature operation of a mid-wave and possibly long-wave infrared spectrometer.

  12. Lightweight Thermally Stable Multi-Meter Aperture Submillimeter Reflectors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Future astrophysics missions will require lightweight, thermally stable, submillimeter reflectors in sizes of 4m and greater. To date, graphite fiber reinforced...

  13. Origins Space Telescope: HEterodyne Receiver for OST (HERO)

    Science.gov (United States)

    Bergin, Edwin; Wiedner, Martina; Laurens, Andre; Gerin, Maryvonne; HERO team, Origins Space Telescope Science and Technology Definition Team

    2018-01-01

    The Origins Space Telescope (OST) is a mission concept for the Far-Infrared Surveyor, one of the four science and technology definition studies selected by NASA HQ for the 2020 Astronomy and Astrophysics Decadal survey. The OST study will encompass two mission concepts (poster by A. Cooray). Concept 1 is an extremely versatile observatory with 5 science instruments, of which the HEterodyne Receivers for OST (HERO) is one.HERO’s main targets are high spectral resolution observations (Dl/l up to 107 or Dv = 0.03km/s) of water to follow its trail from cores to YSOs as well as H2O and HDO observations on comets to explore the origins of water. HERO will probe all neutral ISM phases using cooling lines ([CII], [OI]) and hydrides as probes of CO-dark H2 (CH, HF). HERO will reveal how molecular clouds and filaments form in the local ISM up to nearby galaxies. HERO will enable detailed understanding of feedback mechanisms : shocks, cosmic rays, UV induced feedback and will provide a map of the cosmic ray ionization rate in the Galaxy and nearby galaxies using molecular ions (ArH+, OH+, H3O+).In order to achieve these observational goals, HERO will cover an extremely wide frequency range from 468 to 2700 GHz (641 to 111microns) and a window around the OI line at 4563 to 4752GHz (66 to 63 microns). It will consist of very large focal plane arrays of 128 pixels between 900 - 2700 GHz and at 4.7 THz, and 32 pixels for the 468 to 900 GHz range. The instrument is exploiting Herschel/HIFI heritage, but will go well beyond HIFIs capacities. HERO’s large arrays require low dissipation and low power components. The HERO concept makes use of the latest cryogenic SiGe amplifier technology, as well as CMOS technology for the backends with 2 orders of magnitude lower power. Advances in Local Oscillator technology have also been taken into account and ambitious, but realistic assumptions have been made for future amplifier multiplier chains going up to 4.7 THz.Origins will enable

  14. Velocity measurement by coherent x-ray heterodyning

    Energy Technology Data Exchange (ETDEWEB)

    Lhermitte, Julien R. M.; Rogers, Michael C.; Manet, Sabine; Sutton, Mark

    2017-01-01

    We present a small-angle coherent x-ray scattering technique used for measuring flow velocities in slow moving materials. The technique is an extension of X-ray Photon Correlation Spectroscopy (XPCS): It involves mixing the scattering from moving tracer particles with a static reference that heterodynes the signal. This acts to elongate temporal effects caused by flow in homodyne measurements, allowing for a more robust measurement of flow properties. Using coherent x-ray heterodyning, velocities ranging from 0.1 to 10 μm/s were measured for a viscous fluid pushed through a rectangular channel. We describe experimental protocols and theory for making these Poiseuille flow profile measurements and also develop the relevant theory for using heterodyne XPCS to measure velocities in uniform and Couette flows.

  15. Multi-Axis Heterodyne Interferometry (MAHI)

    Science.gov (United States)

    Thorpe, James

    The detection and measurement of gravitational waves represents humanity’s next, and final, opportunity to open an entirely new spectrum with which to view the universe. The first steps of this process will likely take place later this decade when the second-generation ground-based instruments such as Advanced LIGO approach design sensitivity. While these events will be historic, it will take a space-based detector to access the milliHertz gravitational wave frequency band, a band that is rich in both number and variety of sources. The Laser Interferometer Space Antenna (LISA) concept has been developed over the past two decades in the US and Europe to provide access to this band. The European Space Agency recently selected The Gravitational Universe as the science theme for the 3rd Large-class mission in the Cosmic Visions Programme, with the assumption that a LISA-like instrument would be implemented for launch in 2034. NASA has expressed interest in partnering on this effort and the US community has made its own judgment on the scientific potential of a space-based gravitational wave observatory through the selection of LISA as the 3rd flagship mission in the 2010 Decadal Survey. Much of the effort has been in retiring risk for the unique technologies that comprise a gravitational wave detector. A prime focus of this effort is LISA Pathfinder (LPF), a dedicated technology demonstrator mission led by ESA with contributions from NASA and several member states. LPF’s primary objective is to validate drag-free flight as an approach to realizing an inertial reference mass. Along the way, several important technologies will be demonstrated, including picometer-level heterodyne interferometry. However, there are several important differences between the interferometry design for LISA and that for LPF. These mostly result from the fact that LISA interferometry involves multiple lasers on separate spacecraft whereas LPF can use a single laser on a single spacecraft

  16. Adaptable radiative transfer innovations for submillimeter telescopes (ARTIST)

    DEFF Research Database (Denmark)

    Padovani, Marco; Jørgensen, Jes Kristian; Bertoldi, Frank

    2011-01-01

    Submillimeter observations are a key for answering many of the big questions in modern-day astrophysics, such as how stars and planets form, how galaxies evolve, and how material cycles through stars and the interstellar medium. With the upcoming large submillimeter facilities ALMA and Herschel...

  17. Probing Galaxy Formation and Submillimeter Surveys

    Science.gov (United States)

    Dwek, Eli; Arendt, Richard G.; Benford, Dominic J.; Moseley, Harvey S.; Shafer, Richard A.; Staguhn, Johannes G.; Fisher, Richard R. (Technical Monitor)

    2002-01-01

    Multiwavelength observations of galaxies have revealed that a significant fraction of the their stellar or accretion luminosity is absorbed and reradiated by dust at far-infrared (FIR) and submillimeter (submm) wavelengths. Submillimeter (850 micron) surveys conducted by the SCUBA instrument on the JCMT have detected a population of high redshift (z approximately equal to 1-4) ultraluminous infrared galaxies, that dominate the luminosity densities at those redshifts. Their cumulative contribution to the cosmic infrared background (CIB) detected by the COBE satellite is comparable to the observations, suggesting that at 850 microns the CIB is resolved into its constituent sources. This suggests that the early universe was much more dust enshrouded than the present one. FIR and submm surveys can therefore address fundamental questions regarding the early processes of galaxy formation and their evolution in number and luminosity over cosmic history. The scientific information that can be obtained from such surveys depend on a number of parameters, the most important of which are the diameter of the telescope and the wavelengths of the survey. We summarize the effect of these parameters on the scientific return from such surveys.

  18. Submillimeter Spectroscopy of the R Coronae Australis Molecular Cloud Region

    Science.gov (United States)

    Dunn, Marina Madeline; Walker, Christopher K.; Pat, Terrance; Sirsi, Siddhartha; Swift, Brandon J.; Peters, William L.

    2018-01-01

    The Interstellar Medium is comprised of large amounts of gas and dust which coalesce to form stars. Observing in the Terahertz regime of the electromagnetic spectrum, approximately 0.3 -300 microns, allows astronomers to study the ISM in unprecedented detail. Using the high spectral resolution imaging system of the SuperCam receiver, a 64-pixel array previously installed on the Submillimeter Telescope on Mt. Graham, AZ, we have begun a 500 square degree survey of the galactic plane. This instrument was designed to do a complete survey of the Milky Way from the ground, with the main focus being to observe two specific transitions of the carbon monoxide molecule, 12CO(3-2) and 13CO(3-2), at 345 GHz. In this work, we present results from these observations for the R Coronae Australis (R Cr A) complex, a region in the southern hemisphere of the sky, using spectroscopic data from a portion of the survey to gain better insight into the life cycle of the ISM. The majority of stars being formed here are similar to the stellar class of the Sun, making it an excellent area of observing interest. Using these results, we attempt to better ascertain the large-scale structure and kinematics inside of the molecular cloud.

  19. Range imager performance comparison in homodyne and heterodyne operating modes

    Science.gov (United States)

    Conroy, Richard M.; Dorrington, Adrian A.; Künnemeyer, Rainer; Cree, Michael J.

    2009-01-01

    Range imaging cameras measure depth simultaneously for every pixel in a given field of view. In most implementations the basic operating principles are the same. A scene is illuminated with an intensity modulated light source and the reflected signal is sampled using a gain-modulated imager. Previously we presented a unique heterodyne range imaging system that employed a bulky and power hungry image intensifier as the high speed gain-modulation mechanism. In this paper we present a new range imager using an internally modulated image sensor that is designed to operate in heterodyne mode, but can also operate in homodyne mode. We discuss homodyne and heterodyne range imaging, and the merits of the various types of hardware used to implement these systems. Following this we describe in detail the hardware and firmware components of our new ranger. We experimentally compare the two operating modes and demonstrate that heterodyne operation is less sensitive to some of the limitations suffered in homodyne mode, resulting in better linearity and ranging precision characteristics. We conclude by showing various qualitative examples that demonstrate the system's three-dimensional measurement performance.

  20. Higher moments of scattered light fields by heterodyne analysis

    Science.gov (United States)

    Harris, M.; Paerson, G. N.; Hill, C. A.; Vaughan, J. M.

    1994-10-01

    A simple scattering experiment employing heterodyne detection and operating in Gaussian scattering regime (with large number of illuminated independent scatterers) is shown to yield experimental values of higher-order moments of scattered light intensity distribution in agreement with theoretical predictions. This permits assessment of Gaussian behavior. Laser light scattering from a rotating glass screen is used in the study.

  1. Millimeter and submillimeter spectrum of propylene oxide

    Science.gov (United States)

    Mesko, A. J.; Zou, Luyao; Carroll, P. Brandon; Widicus Weaver, Susanna L.

    2017-05-01

    The spectrum of propylene oxide was collected from 70 GHz to 1 THz using direct absorption millimeter and submillimeter spectroscopy. Analysis of the spectrum was performed using the SPFIT/SPCAT programs for the A state. A full internal rotor analysis was performed using the XIAM program. The barrier to internal rotation of the methyl group was determined to be 893 cm-1. The precision of the rotation constants, centrifugal distortion constants, and internal rotor parameters was increased over the results reported by previous low-frequency studies. The results of this laboratory study and the associated analysis, as well as a spectral prediction for the ground vibrational state of propylene oxide, are presented.

  2. Millimeter and Submillimeter Observations of Ceres

    Science.gov (United States)

    Kuan, Yi-Jehng; Chuang, Yo-Ling; Tseng, Wei-Ling; Coulson, Iain M.; Chung, Ming-Chi

    2016-07-01

    1 Ceres is the largest celestial body in the Main Asteroid Belt and is also the sole dwarf planet in the inner solar system. Water vapor from small icy solar-system bodies, including Ceres and Europa, was detected by Herschel infrared space telescope recently. Data taken from Dawn spacecraft suggest that a subsurface layer of briny water ice, together with ammonia-rich clays, may exist on Ceres. We hence observed Ceres using the 15-m James Clerk Maxwell Telescope (JCMT) to search for other atmospheric molecules besides H _{2}O. Submillimeter continuum observations employing SCUBA-2 were also carried out. Here we report the tentative detection of hydrogen cyanide in the atmosphere of Ceres. If confirmed, our finding could imply that Ceres may have a comet-like chemical composition. However, further observational confirmation and more detailed analysis is needed.

  3. Single beam write and/or replay of spatial heterodyne holograms

    Science.gov (United States)

    Thomas, Clarence E.; Hanson, Gregory R.

    2007-11-20

    A method of writing a spatially heterodyne hologram having spatially heterodyne fringes includes: passing a single write beam through a spatial light modulator that digitally modulates said single write beam; and focusing the single write beam at a focal plane of a lens to impose a holographic diffraction grating pattern on the photorefractive crystal, the holographic diffraction grating pattern including the spatially heterodyne hologram having spatially heterodyne fringes, wherein only said single write beam is incident on said photorefractive crystal without a reference beam. A method of replaying a spatially heterodyne hologram having spatially heterodyne fringes at a replay angle includes: illuminating a photorefractive crystal having a holographic diffraction grating with a beam from a laser at an illumination angle, the holographic diffraction grating pattern including the spatially heterodyne hologram having spatially heterodyne fringes, wherein a difference between said illumination angle and said replay angle defines a diffraction angle .alpha. that is a function of a plane wave mathematically added to original object wave phase and amplitude data of said spatially heterodyne hologram having spatially heterodyne fringes.

  4. Recording multiple spatially-heterodyned direct to digital holograms in one digital image

    Science.gov (United States)

    Hanson, Gregory R [Clinton, TN; Bingham, Philip R [Knoxville, TN

    2008-03-25

    Systems and methods are described for recording multiple spatially-heterodyned direct to digital holograms in one digital image. A method includes digitally recording, at a first reference beam-object beam angle, a first spatially-heterodyned hologram including spatial heterodyne fringes for Fourier analysis; Fourier analyzing the recorded first spatially-heterodyned hologram by shifting a first original origin of the recorded first spatially-heterodyned hologram to sit on top of a first spatial-heterodyne carrier frequency defined by the first reference beam-object beam angle; digitally recording, at a second reference beam-object beam angle, a second spatially-heterodyned hologram including spatial heterodyne fringes for Fourier analysis; Fourier analyzing the recorded second spatially-heterodyned hologram by shifting a second original origin of the recorded second spatially-heterodyned hologram to sit on top of a second spatial-heterodyne carrier frequency defined by the second reference beam-object beam angle; applying a first digital filter to cut off signals around the first original origin and define a first result; performing a first inverse Fourier transform on the first result; applying a second digital filter to cut off signals around the second original origin and define a second result; and performing a second inverse Fourier transform on the second result, wherein the first reference beam-object beam angle is not equal to the second reference beam-object beam angle and a single digital image includes both the first spatially-heterodyned hologram and the second spatially-heterodyned hologram.

  5. A Submillimeter Resolution PET Prototype Evaluated With an 18F Inkjet Printed Phantom

    Science.gov (United States)

    Schneider, Florian R.; Hohberg, Melanie; Mann, Alexander B.; Paul, Stephan; Ziegler, Sibylle I.

    2015-10-01

    This work presents a submillimeter resolution PET (Positron Emission Tomography) scanner prototype based on SiPM/MPPC arrays (Silicon Photomultiplier/Multi Pixel Photon Counter). Onto each active area a 1 ×1 ×20 mm3 LYSO (Lutetium-Yttrium-Oxyorthosilicate) scintillator crystal is coupled one-to-one. Two detector modules facing each other in a distance of 10.0 cm have been set up with in total 64 channels that are digitized by SADCs (Sampling Analog to Digital Converters) with 80 MHz, 10 bit resolution and FPGA (Field Programmable Gate Array) based extraction of energy and time information. Since standard phantoms are not sufficient for testing submillimeter resolution at which positron range is an issue, a 18F inkjet printed phantom has been used to explore the limit in spatial resolution. The phantom could be successfully reconstructed with an iterative MLEM (Maximum Likelihood Expectation Maximization) and an analytically calculated system matrix based on the DRF (Detector Response Function) model. The system yields a coincidence time resolution of 4.8 ns FWHM, an energy resolution of 20%-30% FWHM and a spatial resolution of 0.8 mm.

  6. MKID multicolor array status and results from DemoCam

    Science.gov (United States)

    Schlaerth, James A.; Czakon, Nicole G.; Day, Peter K.; Downes, Thomas P.; Duan, Ran; Gao, Jiansong; Glenn, Jason; Golwala, Sunil R.; Hollister, Matthew I.; LeDuc, Henry G.; Mazin, Benjamin A.; Maloney, Philip R.; Noroozian, Omid; Nguyen, Hien T.; Sayers, Jack; Siegel, Seth; Vaillancourt, John E.; Vayonakis, Anastasios; Wilson, Philip R.; Zmuidzinas, Jonas

    2010-07-01

    We present the results of the latest multicolor Microwave Kinetic Inductance Detector (MKID) focal plane arrays in the submillimeter. The new detectors on the arrays are superconducting resonators which combine a coplanar waveguide section with an interdigitated capacitor, or IDC. To avoid out-of-band pickup by the capacitor, a stepped-impedance filter is used to prevent radiation from reaching the absorptive aluminum section of the resonator. These arrays are tested in the preliminary demonstration instrument, DemoCam, a precursor to the Multicolor Submillimeter Inductance Camera, MUSIC. We present laboratory results of the responsivity to light both in the laboratory and at the Caltech Submillimeter Observatory. We assess the performance of the detectors in filtering out-of-band radiation, and find the level of excess load and its effect on detector performance. We also look at the array design characteristics, and the implications for the optimization of sensitivities expected by MUSIC.

  7. Lightweight Thermally Stable Multi-Meter Aperture Submillimeter Reflectors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of the Phase II effort will be an affordable demonstrated full-scale design for a thermally stable multi-meter submillimeter reflector. The Phase I...

  8. Probabilistic shaping for ROF system with heterodyne coherent detection

    Directory of Open Access Journals (Sweden)

    Bo Liu

    2017-05-01

    Full Text Available We investigate and compare the performance of normal and probabilistic shaping (PS 16-ary quadrature amplitude modulation (16QAM in a photonic vector millimeter-wave (mm-wave signal generation system adopting heterodyne coherent detection. And we obtain a better bit-error ratio (BER performance in the PS 16QAM scheme compared to the normal 16QAM scheme in the simulation. We also for the first time experimentally demonstrate the feasibility of PS-polarization-division-multiplexing 16QAM in a photonic vector mm-wave signal generation system employing heterodyne coherent detection. We obtain the same BER in PS and normal schemes with the PS scheme providing a higher bit rate. Then we experimentally carry out the performance investigation of PS in a 16QAM-modulated radio over fiber system with 40 m wireless transmission.

  9. Piezoelectric dilatometric analysis using homodyne and heterodyne laser interferometry

    Science.gov (United States)

    Delahoussaye, Keith

    The electromechanical coupling of piezoelectric materials has been widely studied since such property is found to be a key element of enhanced sensitivity in piezoelectric sensors or actuators. However a unified view of this coupling as function of frequencies verified using multiple measurement techniques has not previously been available. This study examines and compares multiple optical based homodyne and heterodyne interferometry techniques for piezoelectric displacement measurement, over a wide range of frequencies from DC to 20 MHz. A custom configured homodyne optical interferometer and a commercial heterodyne Laser Doppler Vibrometer are used in the study. Because the frequency ranges used by these devices overlap, it is possible to compare the results. Ferroelectric lead titanate PbTiO3 (PT) ceramic sample with high ferroelectric strain is studied in this work. Frequency dependence of the electromechanical displacement is obtained using multiple techniques and the emphasis of the interrogations is given to frequencies near piezoelectric resonances.

  10. Probabilistic shaping for ROF system with heterodyne coherent detection

    Science.gov (United States)

    Liu, Bo; Li, Xinying; Zhang, Ying; Xin, Xiangjun; Yu, Jianjun

    2017-05-01

    We investigate and compare the performance of normal and probabilistic shaping (PS) 16-ary quadrature amplitude modulation (16QAM) in a photonic vector millimeter-wave (mm-wave) signal generation system adopting heterodyne coherent detection. And we obtain a better bit-error ratio (BER) performance in the PS 16QAM scheme compared to the normal 16QAM scheme in the simulation. We also for the first time experimentally demonstrate the feasibility of PS-polarization-division-multiplexing 16QAM in a photonic vector mm-wave signal generation system employing heterodyne coherent detection. We obtain the same BER in PS and normal schemes with the PS scheme providing a higher bit rate. Then we experimentally carry out the performance investigation of PS in a 16QAM-modulated radio over fiber system with 40 m wireless transmission.

  11. Spatial-heterodyne spectrometer for transmission-Raman observations.

    Science.gov (United States)

    Foster, M J; Storey, J; Zentile, M A

    2017-01-23

    A new transmission Raman spectrometer has been developed using a spatial heterodyne spectrometer (SHS), taking advantage of the high etendue inherent in this class of spectrometer to maximize the light collected from the target. The system has been tested against paracetamol tablet samples. The instrument has been shown to accept light from 0.05 mm up to a 3 mm core diameter fibre bundle with a numerical aperture of 0.22, whilst no degradation in resolution is observed.

  12. Molecular Spectroscopy With a Compact 557-GHz Heterodyne Receiver

    OpenAIRE

    Neumaier, Philipp F.-X.; Richter, Heiko; Stake, Jan; Zhao, Huan; Tang, Aik-Yean; Drakinskiy, Vladimir; Sobis, Peter; Emrich, Anders; Hülsmann, Axel; Johansen, Tom K.; Bryllert, Tomas; Hanning, Johanna; Krozer, Viktor; Hübers, Heinz-Wilhelm

    2014-01-01

    We report on a heterodyne terahertz spectrometer based on a fully integrated 557-GHz receiver and a digital fast Fourier transform spectrometer. The receiver consists of a chain of multipliers and power amplifiers, followed by a heterostructure barrier varactor tripler that subharmonically pumps a membrane GaAs Schottky diode mixer. All sub-components are newly developed and optimized with regard to the overall receiver performance such as noise temperature, power consumption, weight and phys...

  13. Evidence for Dust Clearing Through Resolved Submillimeter Imaging

    Science.gov (United States)

    Brown, J. M.; Blake, G. A.; Qi, C.; Dullemond, C. P.; Wilner, D. J.; Williams, J. P.

    2009-10-01

    Mid-infrared spectrophotometric observations have revealed a small subclass of circumstellar disks with spectral energy distributions (SEDs) suggestive of large inner gaps with low dust content. However, such data provide only an indirect and model-dependent method of finding central holes. Imaging of protoplanetry disks provides an independent check of SED modeling. We present here the direct characterization of three 33-47 AU radii inner gaps, in the disks around LkHα 330, SR 21N, and HD 135344B, via 340 GHz (880 μm) dust continuum aperture synthesis observations obtained with the Submillimeter Array (SMA). The large gaps are fully resolved at ~0farcs3 by the SMA data and mostly empty of dust, with less than (1-7.5) × 10-6 M sun of fine grained solids inside the holes. Gas (as traced by atomic accretion markers and CO 4.7 μm rovibrational emission) is still present in the inner regions of all three disks. For each, the inner hole exhibits a relatively steep rise in dust emission to the outer disk, a feature more likely to originate from the gravitational influence of a companion body than from a process expected to show a more shallow gradient like grain growth. Importantly, the good agreement between the spatially resolved data and spectrophotometry-based models lends confidence to current interpretations of SEDs, wherein the significant dust emission deficits arise from disks with inner gaps or holes. Further SED-based searches can therefore be expected to yield numerous additional candidates that can be examined at high spatial resolution.

  14. Heterodyne QELS instrument for diagnostics of biological fluids

    Science.gov (United States)

    Lebedev, Andrei D.; Ivanova, Mariya A.; Lomakin, Aleksey V.; Noskin, Valentin A.

    1997-05-01

    The instrument for the quasielastic light scattering (QELS), LCS-03 utilizes heterodyne optical scheme which permits a high resolution determination of particle size distribution. The vibration related problems, which are common for the heterodyne techniques, have been overcome by using a single glass block incorporating all the optical elements. The real-time correlation analysis of the photocurrent fluctuations is performed by a PC-embedded analog-to-digit converter card with digital signal processor (DSP) using an original algorithm. Both the technical specifications of the instrument and the software for the size distribution analysis are presented. The heterodyne technique consistently outperforms the homodyne one when the accurate characterization of the particle size distributions in heterogeneous systems is required. Diagnostic analysis of size distribution of particles in blood serum/plasma, liquor and saliva is such an application. This kind of diagnostics usually requires a simultaneous analysis of huge number of QELS data. The original statistical algorithm with graphic user interface is described. We discuss the technical specifications of instrumentation as well as methodical problems of biological fluids QELS diagnostics.

  15. Infrared Heterodyne Spectroscopy and its Unique Application to Planetary Studies

    Science.gov (United States)

    Kostiuk, Theodore

    2009-01-01

    Since the early 1970's the infrared heterodyne technique has evolved into a powerful tool for the study of molecular constituents, temperatures, and dynamics in planetary atmospheres. Its extremely high spectral resolution (Lambda/(Delta)Lambda/>10(exp 6)) and highly accurate frequency measurement (to 1 part in 10(exp 8)) enabled the detection of nonthermal/natural lasing phenomena on Mars and Venus; direct measurements of winds on Venus, Mars, and Titan; study of mid-infrared aurorae on Jupiter; direct measurement of species abundances on Mars (ozone, isotopic CO2), hydrocarbons on Jupiter, Saturn., Neptune, and Titan, and stratospheric composition in the Earth's stratosphere (O3, CIO, N2O, CO2 ....). Fully resolved emission and absorption line shapes measured by this method enabled the unambiguous retrieval of molecular abundances and local temperatures and thermal structure in regions not probed by other techniques. The mesosphere of Mars and thermosphere of Venus are uniquely probed by infrared heterodyne spectroscopy. Results of these studies tested and constrained photochemical and dynamical theoretical models describing the phenomena measured. The infrared heterodyne technique will be described. Highlights in its evolution to today's instrumentation and resultant discoveries will be presented, including work at Goddard Space Flight Center and the University of Koln. Resultant work will include studies supporting NASA and ESA space missions and collaborations between instrumental and theoretical groups.

  16. A Submillimeter HCN Laser in IRC +10216.

    Science.gov (United States)

    Schilke; Mehringer; Menten

    2000-01-01

    We report the detection of a strong submillimeter-wavelength HCN laser line at a frequency near 805 GHz toward the carbon star IRC +10216. This line, the J=9-8 rotational transition within the (0400) vibrationally excited state, is one of a series of HCN laser lines that were first detected in the laboratory in the early days of laser spectroscopy. Since its lower energy level is 4200 K above the ground state, the laser emission must arise from the innermost part of IRC +10216's circumstellar envelope. To better characterize this environment, we observed other, thermally emitting, vibrationally excited HCN lines and found that they, like the laser line, arise in a region of temperature approximately 1000 K that is located within the dust formation radius; this conclusion is supported by the line width of the laser. The (0400), J=9-8 laser might be chemically pumped and may be the only known laser (or maser) that is excited both in the laboratory and in space by a similar mechanism.

  17. Black Holes and Sub-millimeter Dimensions

    CERN Document Server

    Argyres, Philip C; March-Russell, John David; Argyres, Philip C.; Dimopoulos, Savas; March-Russell, John

    1998-01-01

    Recently, a new framework for solving the hierarchy problem was proposed which does not rely on low energy supersymmetry or technicolor. The fundamental Planck mass is at a TeV and the observed weakness of gravity at long distances is due the existence of new sub-millimeter spatial dimensions. In this letter, we study how the properties of black holes are altered in these theories. Small black holes---with Schwarzschild radii smaller than the size of the new spatial dimensions---are quite different. They are bigger, colder, and longer-lived than a usual $(3+1)$-dimensional black hole of the same mass. Furthermore, they primarily decay into harmless bulk graviton modes rather than standard-model degrees of freedom. We discuss the interplay of our scenario with the holographic principle. Our results also have implications for the bounds on the spectrum of primordial black holes (PBHs) derived from the photo-dissociation of primordial nucleosynthesis products, distortion of the diffuse gamma-ray spectrum, overcl...

  18. Infrared/submillimeter optical properties data base

    Science.gov (United States)

    Alley, Phillip W.

    1989-01-01

    The general goal was to build a data base containing optical properties, such as reflectance, transmittance, refractive index, in the far infrared to submillimeter wavelength region. This data base would be limited to selected crystalline materials and temperature between 300 and 2 K. The selected materials were: lithium, lead, and strontium; the bromides of potassium and thallium; the carbides of silicone and tungsten; and the materials of KRS5, KRS6, diamond, and sapphire. Last summer, barium fluoride was selected as prototype material for building the data base. This summer the literature search, preparation of the data for barium fluoride was completed. In addition the literature search for data related to the compounds mentioned was completed. The current status is that barium fluoride is in a form suitable for a NASA internal publication. The papers containing the data on the other materials were xeroxed and they are ready to be reduced. On the reverse side, the top figure is a sample combination of data for the index of refraction at 300 K. The lower figure shows the transmittance vs wavelength at 300 and 80 K. These figures are a sample of many which were developed. Since barium fluoride was studied more than most of the materials listed above, it is clear that additional measurements should be made to fill in the gaps present on both temperature and wavelength data.

  19. A Submillimeter Perspective on the Goods Fields. II. The High Radio Power Population in the Goods-N

    Science.gov (United States)

    Barger, A. J.; Cowie, L. L.; Owen, F. N.; Hsu, L.-Y.; Wang, W.-H.

    2017-01-01

    We use ultradeep 20 cm data from the Karl G. Jansky Very Large Array and 850 μm data from SCUBA-2 and the Submillimeter Array of an 124 arcmin2 region of the Chandra Deep Field-north to analyze the high radio power ({P}20{cm}> {10}31 erg s-1 Hz-1) population. We find that 20 (42 ± 9%) of the spectroscopically identified z> 0.8 sources have consistent star formation rates (SFRs) inferred from both submillimeter and radio observations, while the remaining sources have lower (mostly undetected) submillimeter fluxes, suggesting that active galactic nucleus (AGN) activity dominates the radio power in these sources. We develop a classification scheme based on the ratio of submillimeter flux to radio power versus radio power and find that it agrees with AGN and star-forming galaxy classifications from Very Long Baseline Interferometry. Our results provide support for an extremely rapid drop in the number of high SFR galaxies above about a thousand solar masses per year (Kroupa initial mass function) and for the locally determined relation between X-ray luminosity and radio power for star-forming galaxies applying at high redshifts and high radio powers. We measure far-infrared (FIR) luminosities and find that some AGNs lie on the FIR-radio correlation, while others scatter below. The AGNs that lie on the correlation appear to do so based on their emission from the AGN torus. We measure a median radio size of 1.″0 ± 0.3 for the star-forming galaxies. The radio sizes of the star-forming galaxies are generally larger than those of the AGNs. The W. M. Keck Observatory is operated as a scientific partnership among the California Institute of Technology, the University of California, and NASA, and was made possible by the generous financial support of the W. M. Keck Foundation.

  20. Fabrication of an absorber-coupled MKID detector and readout for sub-millimeter and far-infrared astronomy

    Science.gov (United States)

    Brown, Ari-David; Hsieh, Wen-Ting; Moseley, S. Harvey; Stevenson, Thomas R.; U-yen, Kongpop; Wollack, Edward J.

    2010-07-01

    We have fabricated absorber-coupled microwave kinetic inductance detector (MKID) arrays for sub-millimeter and farinfrared astronomy. Each detector array is comprised of λ/2 stepped impedance resonators, a 1.5μm thick silicon membrane, and 380μm thick silicon walls. The resonators consist of parallel plate aluminum transmission lines coupled to low impedance Nb microstrip traces of variable length, which set the resonant frequency of each resonator. This allows for multiplexed microwave readout and, consequently, good spatial discrimination between pixels in the array. The Al transmission lines simultaneously act to absorb optical power and are designed to have a surface impedance and filling fraction so as to match the impedance of free space. Our novel fabrication techniques demonstrate high fabrication yield of MKID arrays on large single crystal membranes and sub-micron front-to-back alignment of the microstrip circuit.

  1. Fabrication of an Absorber-Coupled MKID Detector and Readout for Sub-Millimeter and Far-Infrared Astronomy

    Science.gov (United States)

    Brown, Ari-David; Hsieh, Wen-Ting; Moseley, S. Harvey; Stevenson, Thomas R.; U-yen, Kongpop; Wollack, Edward J.

    2010-01-01

    We have fabricated absorber-coupled microwave kinetic inductance detector (MKID) arrays for sub-millimeter and farinfrared astronomy. Each detector array is comprised of lambda/2 stepped impedance resonators, a 1.5µm thick silicon membrane, and 380µm thick silicon walls. The resonators consist of parallel plate aluminum transmission lines coupled to low impedance Nb microstrip traces of variable length, which set the resonant frequency of each resonator. This allows for multiplexed microwave readout and, consequently, good spatial discrimination between pixels in the array. The Al transmission lines simultaneously act to absorb optical power and are designed to have a surface impedance and filling fraction so as to match the impedance of free space. Our novel fabrication techniques demonstrate high fabrication yield of MKID arrays on large single crystal membranes and sub-micron front-to-back alignment of the microstrip circuit.

  2. The SOFIA/SAFIRE Far-Infrared Spectrometer: Highlighting Submillimeter Astrophysics and Technology

    Science.gov (United States)

    Benford, Dominic J.

    2009-01-01

    The Submillimeter and Far-InfraRed Experiment (SAFIRE) on the SOFIA airborne observatory is an imaging spectrometer for wavelengths between 28 microns and 440 microns. Our design is a dual-band long-slit grating spectrometer, which provides broadband (approx. 4000 km/s) observations in two lines simultaneously over a field of view roughly 10" wide by 320" long. The low backgrounds in spectroscopy require very sensitive detectors with noise equivalent powers of order 10(exp -18) W/square root of Hz. We are developing a kilopixel, filled detector array for SAFIRE in a 32 x 40 format. The detector consists of a transition edge sensor (TES) bolometer array, a per-pixel broadband absorbing backshort array, and a NIST SQUID multiplexer readout array. This general type of array has been used successfully in the GISMO instrument, so we extrapolate to the sensitivity needed for airborne spectroscopy. Much of the cryogenic, electronics, and software infrastructure for SAFIRE have been developed. I provide here an overview of the progress on SAFIRE.

  3. Heterodyne pump probe measurements of nonlinear dynamics in an indium phosphide photonic crystal cavity

    DEFF Research Database (Denmark)

    Heuck, Mikkel; Combrié, S.; Lehoucq, G.

    2013-01-01

    Using a sensitive two-color heterodyne pump-probe technique, we investigate the carrier dynamics of an InP photonic crystal nanocavity. The heterodyne technique provides unambiguous results for all wavelength configurations, including the degenerate case, which cannot be investigated with the wid...

  4. The Herschel-Heterodyne Instrument for the Far-Infrared (HIFI)

    NARCIS (Netherlands)

    Graauw, T. de; Helmich, F.P.; Phillips, T.G.; Stutzki, J.; Caux, E.; Whyborn, N.D.; Dieleman, P.; Roelfsema, P.R.; Aarts, H.; Assendorp, R.; Bachiller, R.; Baechtold, W.; Barcia, A.; Beintema, D.A.; Belitsky, V.; Benz, A.O.; Bieber, R.; Boogert, A.; Borys, C.; Bumble, B.; Caïs, P.; Caris, M.; Cerulli-Irelli, P.; Chattopadhyay, G.; Cherednichenko, S.; Ciechanowicz, M.; Coeur-Joly, O.; Comito, C.; Cros, A.; Jonge, A. de; Lange, G. de; Delforges, B.; Delorme, Y.; Boggende, T. den; Desbat, J.M.; Diez-González, C.; Di Giorgio, A.M.; Dubbeldam, L.; Edwards, K.; Eggens, M.; Erickson, N.; Evers, J.; Fich, M.; Finn, T.; Franke, B.; Gaier, T.; Gal, C.; Gao, J.R.; Gallego, J.D.; Gauffre, S.; Gill, J.J.; Glenz, S.; Golstein, H.; Goulooze, H.; Gunsing, T.; Güsten, R.; Hartogh, P.; Hatch, W.A.; Higgins, R.; Honingh, E.C.; Huisman, R.; Jackson, B.D.; Jacobs, H.; Jacobs, K.; Jarchow, C.; Javadi, H.; Jellema, W.; Justen, M.; Karpov, A.; Kasemann, C.; Kawamura, J.; Keizer, G.; Kester, D.; Klapwijk, T.M.; Klein, T.; Kollberg, E.; Kooi, J.; Kooiman, P.P.; Kopf, B.; Krause, M.; Krieg, J.M.; Kramer, C.; Kruizenga, B.; Kuhn, T.; Laauwen, W.; Lai, R.; Larsson, B.; Leduc, H.G.; Leinz, C.; Lin, R.H.; Liseau, R.; Liu, G.S.; Loose, A.; López-Fernandez, I.; Lord, S.; Luinge, W.; Marston, A.; Martín-Pintado, J.; Maestrini, A.; Maiwald, F.W.; McCoey, C.; Mehdi, I.; Megej, A.; Melchior, M.; Meinsma, L.; Merkel, H.; Michalska, M.; Monstein, C.; Moratschke, D.; Morris, P.; Muller, H.; Murphy, J.A.; Naber, A.; Natale, E.; Nowosielski, W.; Nuzzolo, F.; Olberg, M.; Olbrich, M.; Orfei, R.; Orleanski, P.; Ossenkopf, V.; Peacock, T.; Pearson, J.C.; Peron, I.; Phillip-May, S.; Piazzo, L.; Planesas, P.; Rataj, M.; Ravera, L.; Risacher, C.; Salez, M.; Samoska, L.A.; Saraceno, P.; Schieder, R.; Schlecht, E.; Schlöder, F.; Schmülling, F.; Schultz, M.; Schuster, K.; Siebertz, O.; Smit, H.; Szczerba, R.; Shipman, R.; Steinmetz, E.; Stern, J.A.; Stokroos, M.; Teipen, R.; Teyssier, D.; Tils, T.; Trappe, N.; Baaren, C. van; Leeuwen, B.J. van; Stadt, H. van de; Visser, H.; Wildeman, K.J.; Wafelbakker, C.K.; Ward, J.S.; Wesselius, P.; Wild, W.; Wulff, S.; Wunsch, H.J.; Tielens, X.; Zaal, P.; Zirath, H.; Zmuidzinas, J.; Zwart, F.

    2010-01-01

    Aims. This paper describes the Heterodyne Instrument for the Far-Infrared (HIFI) that was launched onboard ESA's Herschel Space Observatory in May 2009. Methods. The instrument is a set of 7 heterodyne receivers that are electronically tuneable, covering 480-1250 GHz with SIS mixers and the

  5. Development Of A Multicolor Sub/millimeter Camera Using Microwave Kinetic Inductance Detectors

    Science.gov (United States)

    Schlaerth, James A.; Czakon, N. G.; Day, P. K.; Downes, T. P.; Duan, R.; Glenn, J.; Golwala, S. R.; Hollister, M. I.; LeDuc, H. G.; Maloney, P. R.; Mazin, B. A.; Noroozian, O.; Sayers, J.; Siegel, S.; Vayonakis, A.; Zmuidzinas, J.

    2011-01-01

    Microwave Kinetic Inductance Detectors (MKIDs) are superconducting resonators useful for detecting light from the millimeter-wave to the X-ray. These detectors are easily multiplexed, as the resonances can be tuned to slightly different frequencies, allowing hundreds of detectors to be read out simultaneously using a single feedline. The Multicolor Submillimeter Inductance Camera, MUSIC, will use 2304 antenna-coupled MKIDs in multicolor operation, with bands centered at wavelengths of 0.85, 1.1, 1.3 and 2.0 mm, beginning in 2011. Here we present the results of our demonstration instrument, DemoCam, containing a single 3-color array with 72 detectors and optics similar to MUSIC. We present sensitivities achieved at the telescope, and compare to those expected based upon laboratory tests. We explore the factors that limit the sensitivity, in particular electronics noise, antenna efficiency, and excess loading. We discuss mitigation of these factors, and how we plan to improve sensitivity to the level of background-limited performance for the scientific operation of MUSIC. Finally, we note the expected mapping speed and contributions of MUSIC to astrophysics, and in particular to the study of submillimeter galaxies. This research has been funded by grants from the National Science Foundation, the Gordon and Betty Moore Foundation, and the NASA Graduate Student Researchers Program.

  6. Sideband-Separating, Millimeter-Wave Heterodyne Receiver

    Science.gov (United States)

    Ward, John S.; Bumble, Bruce; Lee, Karen A.; Kawamura, Jonathan H.; Chattopadhyay, Goutam; Stek, paul; Stek, Paul

    2010-01-01

    Researchers have demonstrated a submillimeter-wave spectrometer that combines extremely broad bandwidth with extremely high sensitivity and spectral resolution to enable future spacecraft to measure the composition of the Earth s troposphere in three dimensions many times per day at spatial resolutions as high as a few kilometers. Microwave limb sounding is a proven remote-sensing technique that measures thermal emission spectra from molecular gases along limb views of the Earth s atmosphere against a cold space background.

  7. A sub-millimeter resolution detector module for small-animal PET applications

    Science.gov (United States)

    Sacco, I.; Dohle, R.; Fischer, P.; Gola, A.; Piemonte, C.; Ritzert, M.

    2017-01-01

    We present a gamma detection module optimized for very high resolution PET applications, able to resolve arrays of scintillating crystals with sub-millimeter pitch. The detector is composed of a single ceramic substrate (LTCC): it hosts four flip-chip mounted PETA5 ASICs on the bottom side and an array of SiPM sensors on the top surface, fabricated in HD-RGB technology by FBK. Each chip has 36 channels, for a maximum of 144 readout channels on a sensitive area of about 32 mm × 32 mm. The module is MR-compatible. The thermal decoupling of the readout electronics from the photon sensors is obtained with an efficient internal liquid channel, integrated within the ceramic substrate. Two modules have been designed, based on different SiPM topologies: • Light spreader-based: an array of 12 × 12 SiPMs, with an overall pitch of 2.5 mm, is coupled with a scintillators array using a 1 mm thick glass plate. The light from one crystal is spread over a group of SiPMs, which are read out in parallel using PETA5 internal neighbor logic. • Interpolating SiPM-based: ISiPMs are intrinsic position-sensitive sensors. The photon diodes in the array are connected to one of the four available outputs so that the center of gravity of any bunch of detected photons can be reconstructed using a proper weight function of the read out amplitudes. An array of ISiPMs, each 7.5 mm× 5 mm sized, is directly coupled with the scintillating crystals. Both modules can clearly resolve LYSO arrays with a pitch of only 0.833 mm. The detector can be adjusted for clinical PET, where it has already shown ToF resolution of about 230 ps CRT at FWHM. The module designs, their features and results are described.

  8. Scanning strategies for imaging arrays

    Science.gov (United States)

    Kovács, Attila

    2008-07-01

    Large-format (sub)millimeter wavelength imaging arrays are best operated in scanning observing modes rather than traditional position-switched (chopped) modes. The choice of observing mode is critical for isolating source signals from various types of noise interference, especially for ground-based instrumentation operating under a bright atmosphere. Ideal observing strategies can combat 1/f noise, resist instrumental defects, sensitively recover emission on large scales, and provide an even field coverage - all under feasible requirements of telescope movement. This work aims to guide the design of observing patterns that maximize scientific returns. It also compares some of the popular choices of observing modes for (sub)millimeter imaging, such as random, Lissajous, billiard, spiral, On-The-Fly (OTF), DREAM, chopped and stare patterns. Many of the conclusions are also applicable other imaging applications and imaging in one dimension (e.g. spectroscopic observations).

  9. Infrared and submillimeter space missions in the coming decade programmes, programmatics, and technology

    CERN Document Server

    Sauvage, Marc; Gallais, Pascal; Vigroux, Laurent

    1996-01-01

    A revolution similar to that brought by CCDs to visible astronomy is still ahead in IR and submillimeter astronomy. There is certainly no wavelength range which has, over the past several years, seen such impressive advances in technology: large-scale detector arrays, new designs for cooling in space, lightweight mirror technologies. Scientific cases for observing the cold universe are outstanding. Observations in the FIR/Submm range will provide answers to such fundamental questions as: What is the spectrum of the primordial fluctuations? How do primeval galaxies look? What are the first stages of star formation? Most of the international space missions that have been triggered by these questions are presented in detail here. Technological issues raised by these missions are reviewed, as are the most recent achievements in cooling and detector technologies.

  10. The ALMA Phasing System: A Beamforming Capability for Ultra-high-resolution Science at (Sub)Millimeter Wavelengths

    Science.gov (United States)

    Matthews, L. D.; Crew, G. B.; Doeleman, S. S.; Lacasse, R.; Saez, A. F.; Alef, W.; Akiyama, K.; Amestica, R.; Anderson, J. M.; Barkats, D. A.; Baudry, A.; Broguière, D.; Escoffier, R.; Fish, V. L.; Greenberg, J.; Hecht, M. H.; Hiriart, R.; Hirota, A.; Honma, M.; Ho, P. T. P.; Impellizzeri, C. M. V.; Inoue, M.; Kohno, Y.; Lopez, B.; Martí-Vidal, I.; Messias, H.; Meyer-Zhao, Z.; Mora-Klein, M.; Nagar, N. M.; Nishioka, H.; Oyama, T.; Pankratius, V.; Perez, J.; Phillips, N.; Pradel, N.; Rottmann, H.; Roy, A. L.; Ruszczyk, C. A.; Shillue, B.; Suzuki, S.; Treacy, R.

    2018-01-01

    The Atacama Millimeter/submillimeter Array (ALMA) Phasing Project (APP) has developed and deployed the hardware and software necessary to coherently sum the signals of individual ALMA antennas and record the aggregate sum in Very Long Baseline Interferometry (VLBI) Data Exchange Format. These beamforming capabilities allow the ALMA array to collectively function as the equivalent of a single large aperture and participate in global VLBI arrays. The inclusion of phased ALMA in current VLBI networks operating at (sub)millimeter wavelengths provides an order of magnitude improvement in sensitivity, as well as enhancements in u–v coverage and north–south angular resolution. The availability of a phased ALMA enables a wide range of new ultra-high angular resolution science applications, including the resolution of supermassive black holes on event horizon scales and studies of the launch and collimation of astrophysical jets. It also provides a high-sensitivity aperture that may be used for investigations such as pulsar searches at high frequencies. This paper provides an overview of the ALMA Phasing System design, implementation, and performance characteristics.

  11. Free-Space Quantum Signatures Using Heterodyne Measurements.

    Science.gov (United States)

    Croal, Callum; Peuntinger, Christian; Heim, Bettina; Khan, Imran; Marquardt, Christoph; Leuchs, Gerd; Wallden, Petros; Andersson, Erika; Korolkova, Natalia

    2016-09-02

    Digital signatures guarantee the authorship of electronic communications. Currently used "classical" signature schemes rely on unproven computational assumptions for security, while quantum signatures rely only on the laws of quantum mechanics to sign a classical message. Previous quantum signature schemes have used unambiguous quantum measurements. Such measurements, however, sometimes give no result, reducing the efficiency of the protocol. Here, we instead use heterodyne detection, which always gives a result, although there is always some uncertainty. We experimentally demonstrate feasibility in a real environment by distributing signature states through a noisy 1.6 km free-space channel. Our results show that continuous-variable heterodyne detection improves the signature rate for this type of scheme and therefore represents an interesting direction in the search for practical quantum signature schemes. For transmission values ranging from 100% to 10%, but otherwise assuming an ideal implementation with no other imperfections, the signature length is shorter by a factor of 2 to 10. As compared with previous relevant experimental realizations, the signature length in this implementation is several orders of magnitude shorter.

  12. Bulk submillimeter-wave mixers: Strain and superlattices

    Science.gov (United States)

    Litvak, M. M.; Pickett, H. M.

    1980-01-01

    Strained germanium crystals, doped with gallium, were used as heterodyne mixers at THz frequencies, with infrared bandwidths approaching a GHz. The mixer performance (conversion loss and mixer noise) was analyzed in terms of nonlinearities associated with acceptor levels and with relaxation rates of free holes. Comparison was made with similar mixers employing low lying donor levels in high purity GaAs and with hot electron InSb mixers.

  13. FPGA-Based Smart Sensor for Online Displacement Measurements Using a Heterodyne Interferometer

    Science.gov (United States)

    Vera-Salas, Luis Alberto; Moreno-Tapia, Sandra Veronica; Garcia-Perez, Arturo; de Jesus Romero-Troncoso, Rene; Osornio-Rios, Roque Alfredo; Serroukh, Ibrahim; Cabal-Yepez, Eduardo

    2011-01-01

    The measurement of small displacements on the nanometric scale demands metrological systems of high accuracy and precision. In this context, interferometer-based displacement measurements have become the main tools used for traceable dimensional metrology. The different industrial applications in which small displacement measurements are employed requires the use of online measurements, high speed processes, open architecture control systems, as well as good adaptability to specific process conditions. The main contribution of this work is the development of a smart sensor for large displacement measurement based on phase measurement which achieves high accuracy and resolution, designed to be used with a commercial heterodyne interferometer. The system is based on a low-cost Field Programmable Gate Array (FPGA) allowing the integration of several functions in a single portable device. This system is optimal for high speed applications where online measurement is needed and the reconfigurability feature allows the addition of different modules for error compensation, as might be required by a specific application. PMID:22164040

  14. Potential of a superconducting photon counter for heterodyne detection at the telecommunication wavelength.

    Science.gov (United States)

    Shcherbatenko, M; Lobanov, Y; Semenov, A; Kovalyuk, V; Korneev, A; Ozhegov, R; Kazakov, A; Voronov, B M; Goltsman, G N

    2016-12-26

    Here, we report on the successful operation of a NbN thin film superconducting nanowire single-photon detector (SNSPD) in a coherent mode (as a mixer) at the telecommunication wavelength of 1550 nm. Providing the local oscillator power of the order of a few picowatts, we were practically able to reach the quantum noise limited sensitivity. The intermediate frequency gain bandwidth (also referred to as response or conversion bandwidth) was limited by the spectral band of a single-photon response pulse of the detector, which is proportional to the detector size. We observed a gain bandwidth of 65 MHz and 140 MHz for 7 × 7 µm2 and 3 × 3 µm2 devices, respectively. A tiny amount of the required local oscillator power and wide gain and noise bandwidths, along with unnecessary low noise amplification, make this technology prominent for various applications, with the possibility for future development of a photon counting heterodyne-born large-scale array.

  15. Submillimeter Wave Antenna With Slow Wave Feed Line

    DEFF Research Database (Denmark)

    Zhurbenko, Vitaliy; Krozer, Viktor; Kotiranta, Mikko

    2009-01-01

    Submillimeter wave radiation, which is also referred to as terahertz radiation, has not been extensively explored until recently due to a lack of reliable components and devices in this frequency range. Current advances in technology have made it possible to explore this portion of the electromag...

  16. Noise Immune Cavity Enhanced Optical Heterodyne Velocity Modulation Spectroscopy

    Science.gov (United States)

    Siller, Brian; Mills, Andrew; Porambo, Michael; McCall, Benjamin

    2011-06-01

    The technique of Cavity Enhanced Velocity Modulation Spectroscopy (CEVMS) has recently been developed. By demodulating the detector signal at twice the plasma modulation frequency (2f), the velocity-modulated ionic absorption signal can be extracted. Although the concentration-modulated excited neutral molecules are also observed at 2f, the ion and neutral signals can be distinguished and separated with phase-sensitive demodulation. The optical cavity provides two major benefits. It increases both the optical path length and the intracavity laser power by a factor of 2×Finesse/π. The multipass advantage allows for much longer path length than was previously possible with unidirectional multipass White cells. The power enhancement combined with perfectly overlapped counterpropagating beams within the cavity allows for sub-Doppler spectroscopy. Although CEVMS showed much potential, its sensitivity was ultimately limited by electronic noise from the plasma interfering with the cavity-locking electronics. We have further improved upon CEVMS by combining it with Noise Immune Cavity Enhanced Optical Heterodyne Molecular Spectroscopy (NICE-OHMS). The laser is frequency modulated at precisely an integer multiple of the free spectral range of the optical cavity; this allows the heterodyne sidebands to be coupled into the optical cavity. Heterodyne detection of the cavity leak-out is immune to noise in the laser-cavity lock, and 2f demodulation further decreases electronic noise in the system and retains ion-neutral discrimination. The additional level of modulation beyond ordinary CEVMS has the added advantage of enabling the observation of both absorption and dispersion signals simultaneously by using two RF mixers, each driving its own lock-in amplifier. In a single scan, four distinct signals can be obtained: absorption and dispersion for ions and excited neutrals. The technique has been demonstrated in the near-IR for N_2^+. B. M. Siller, A. A. Mills and B. J. Mc

  17. Transmission Raman Measurements Using a Spatial Heterodyne Raman Spectrometer (SHRS).

    Science.gov (United States)

    Strange, K Alicia; Paul, Kelly C; Angel, S Michael

    2017-02-01

    A spatial heterodyne Raman spectrometer (SHRS) was used to measure transmission Raman spectra of highly scattering compounds. Transmission Raman spectral intensities of ibuprofen were only 2.4 times lower in intensity than backscatter Raman spectra. The throughput was about eight times higher than an f/1.8 dispersive spectrometer, and the width of the area viewed was found to be seven to nine times higher, using 50.8 mm and 250 mm focal length collection lenses. However, the signal-to-noise (S/N) ratio was two times lower for the SHRS than the f/1.8 dispersive spectrometer, apparently due to high levels of stray light.

  18. Analysis and System Design Framework for Infrared Spatial Heterodyne Spectrometers

    Energy Technology Data Exchange (ETDEWEB)

    Cooke, B.J.; Smith, B.W.; Laubscher, B.E.; Villeneuve, P.V.; Briles, S.D.

    1999-04-05

    The authors present a preliminary analysis and design framework developed for the evaluation and optimization of infrared, Imaging Spatial Heterodyne Spectrometer (SHS) electro-optic systems. Commensurate with conventional interferometric spectrometers, SHS modeling requires an integrated analysis environment for rigorous evaluation of system error propagation due to detection process, detection noise, system motion, retrieval algorithm and calibration algorithm. The analysis tools provide for optimization of critical system parameters and components including : (1) optical aperture, f-number, and spectral transmission, (2) SHS interferometer grating and Littrow parameters, and (3) image plane requirements as well as cold shield, optical filtering, and focal-plane dimensions, pixel dimensions and quantum efficiency, (4) SHS spatial and temporal sampling parameters, and (5) retrieval and calibration algorithm issues.

  19. Self Referencing Heterodyne Transient Grating Spectroscopy with Short Wavelength

    Directory of Open Access Journals (Sweden)

    Jakob Grilj

    2015-04-01

    Full Text Available Heterodyning by a phase stable reference electric field is a well known technique to amplify weak nonlinear signals. For short wavelength, the generation of a reference field in front of the sample is challenging because of a lack of suitable beamsplitters. Here, we use a permanent grating which matches the line spacing of the transient grating for the creation of a phase stable reference field. The relative phase among the two can be changed by a relative translation of the permanent and transient gratings in direction orthogonal to the grating lines. We demonstrate the technique for a transient grating on a VO2 thin film and observe constructive as well as destructive interference signals.

  20. Subsurface contrast due to friction in heterodyne force microscopy

    Science.gov (United States)

    Verbiest, G. J.; Oosterkamp, T. H.; Rost, M. J.

    2017-02-01

    The nondestructive imaging of subsurface structures on the nanometer scale has been a long-standing desire in both science and industry. A few impressive images were published so far that demonstrate the general feasibility by combining ultrasound with an atomic force microscope. From different excitation schemes, heterodyne force microscopy seems to be the most promising candidate delivering the highest contrast and resolution. However, the physical contrast mechanism is unknown, thereby preventing any quantitative analysis of samples. Here we show that friction at material boundaries within the sample is responsible for the contrast formation. This result is obtained by performing a full quantitative analysis, in which we compare our experimentally observed contrasts with simulations and calculations. Surprisingly, we can rule out all other generally believed responsible mechanisms, like Rayleigh scattering, sample (visco)elasticity, damping of the ultrasonic tip motion, and ultrasound attenuation. Our analytical description paves the way for quantitative subsurface-AFM imaging.

  1. Heterodyne x-ray diffuse scattering from coherent phonons.

    Science.gov (United States)

    Kozina, M; Trigo, M; Chollet, M; Clark, J N; Glownia, J M; Gossard, A C; Henighan, T; Jiang, M P; Lu, H; Majumdar, A; Zhu, D; Reis, D A

    2017-09-01

    Here, we report Fourier-transform inelastic x-ray scattering measurements of photoexcited GaAs with embedded ErAs nanoparticles. We observe temporal oscillations in the x-ray scattering intensity, which we attribute to inelastic scattering from coherent acoustic phonons. Unlike in thermal equilibrium, where inelastic x-ray scattering is proportional to the phonon occupation, we show that the scattering is proportional to the phonon amplitude for coherent states. The wavevectors of the observed phonons extend beyond the excitation wavevector. The nanoparticles break the discrete translational symmetry of the lattice, enabling the generation of large wavevector coherent phonons. Elastic scattering of x-ray photons from the nanoparticles provides a reference for heterodyne mixing, yielding signals proportional to the phonon amplitude.

  2. Heterodyne interferometric system with subnanometer accuracy for measurement of straightness.

    Science.gov (United States)

    Wu, Chien-Ming

    2004-07-01

    A generalized laser interferometer system based on three design principles, i.e., heterodyne frequency, prevention of mixing, and perfect symmetry, is described. These design principles give rise to an interferometer in a highly stable system with no periodic nonlinearity. A novel straightness sensor, consisting of a straightness prism and a straightness reflector, is incorporated into the generalized system to form a straightness interferometer. A Hewlett-Packard commercial linear interferometer was used to validate the interferometer's parameters. Based on the present design, the interferometer has a gain of 0.348, a periodic nonlinearity of less than 40 pm, and a displacement noise of 12 pm/mean square root of Hz at a bandwidth of 7.8 kHz. This system is useful for precision straightness measurements.

  3. Adaptive-array Electron Cyclotron Emission diagnostics using data streaming in a Software Defined Radio system

    Science.gov (United States)

    Idei, H.; Mishra, K.; Yamamoto, M. K.; Hamasaki, M.; Fujisawa, A.; Nagashima, Y.; Hayashi, Y.; Onchi, T.; Hanada, K.; Zushi, H.; the QUEST Team

    2016-04-01

    Measurement of the Electron Cyclotron Emission (ECE) spectrum is one of the most popular electron temperature diagnostics in nuclear fusion plasma research. A 2-dimensional ECE imaging system was developed with an adaptive-array approach. A radio-frequency (RF) heterodyne detection system with Software Defined Radio (SDR) devices and a phased-array receiver antenna was used to measure the phase and amplitude of the ECE wave. The SDR heterodyne system could continuously measure the phase and amplitude with sufficient accuracy and time resolution while the previous digitizer system could only acquire data at specific times. Robust streaming phase measurements for adaptive-arrayed continuous ECE diagnostics were demonstrated using Fast Fourier Transform (FFT) analysis with the SDR system. The emission field pattern was reconstructed using adaptive-array analysis. The reconstructed profiles were discussed using profiles calculated from coherent single-frequency radiation from the phase array antenna.

  4. A Monolithic, Non-Field-Widened Spatial Heterodyne Spectrometer for Solar System Exploration Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal of this project is to produce a monolithic Spatial Heterodyne Spectrometer (a Fourier Transform Interferometer) for use in Solar System exploration. In...

  5. Simulated electronic heterodyne recording and processing of pulsed-laser holograms

    Science.gov (United States)

    Decker, A. J.

    1979-01-01

    The electronic recording of pulsed-laser holograms is proposed. The polarization sensitivity of each resolution element of the detector is controlled independently to add an arbitrary phase to the image waves. This method which can be used to simulate heterodyne recording and to process three-dimensional optical images, is based on a similar method for heterodyne recording and processing of continuous-wave holograms.

  6. Structure of multiphoton quantum optics. II. Bipartite systems, physical processes, and heterodyne squeezed states

    Science.gov (United States)

    dell'Anno, Fabio; de Siena, Silvio; Illuminati, Fabrizio

    2004-03-01

    Extending the scheme developed for a single mode of the electromagnetic field in the preceding paper [F. Dell’Anno, S. De Siena, and F. Illuminati, Phys. Rev. A 69, 033812 (2004)], we introduce two-mode nonlinear canonical transformations depending on two heterodyne mixing angles. They are defined in terms of Hermitian nonlinear functions that realize heterodyne superpositions of conjugate quadratures of bipartite systems. The canonical transformations diagonalize a class of Hamiltonians describing nondegenerate and degenerate multiphoton processes. We determine the coherent states associated with the canonical transformations, which generalize the nondegenerate two-photon squeezed states. Such heterodyne multiphoton squeezed states are defined as the simultaneous eigenstates of the transformed, coupled annihilation operators. They are generated by nonlinear unitary evolutions acting on two-mode squeezed states. They are non-Gaussian, highly nonclassical, entangled states. For a quadratic nonlinearity the heterodyne multiphoton squeezed states define two-mode cubic phase states. The statistical properties of these states can be widely adjusted by tuning the heterodyne mixing angles, the phases of the nonlinear couplings, as well as the strength of the nonlinearity. For quadratic nonlinearity, we study the higher-order contributions to the susceptibility in nonlinear media and we suggest possible experimental realizations of multiphoton conversion processes generating the cubic-phase heterodyne squeezed states.

  7. Linewidth of submillimeter wave flux-flow oscillators

    DEFF Research Database (Denmark)

    Koshelets, V.P.; Shitov, S.V.; Shchukin, A.V.

    1996-01-01

    A reliable technique for wide band measurements of the spectral linewidth of superconducting oscillators integrated on-chip with superconductor-insulator-superconductor (SIS) detectors has been, developed, The spectral linewidth of flux-flow oscillators (FFO) based on the unidirectional and visco...... reference source has been demonstrated. The proposed technique may improve the sensitivity, frequency resolution, and stability of the fully superconducting integrated submillimeter wave receiver. (C) 1996 American Institute of Physics....

  8. Passive magnetic shielding for the submillimeter and far infrared experiment

    Energy Technology Data Exchange (ETDEWEB)

    Kamiya, Koji; Warner, B.A.; Di Pirro, M.J.; Numazawa, Takenori

    2003-05-01

    Goddard Space Flight Center is developing the submillimeter and far infrared experiment (SAFIRE). SAFIRE will use SQUIDs as amplifiers for detectors, which must be shielded from the magnet cooling system, an adiabatic demagnetization refrigerator (ADR). The magnetic field at the detector package must remain at or below the 10{sup -7} tesla level while the detectors are operating. We discuss laboratory tests of the passive shielding and simulations.

  9. Analysis of the Sub-Millimeter Rotational Spectrum of Urea

    Science.gov (United States)

    Thomas, Jessica R.; Fosnight, Alyssa M.; Medvedev, Ivan R.

    2013-06-01

    Urea, ((NH_{2})_{2}CO), has broad presence in biological species. As a byproduct of human metabolism, this molecule is commonly tested for in blood to diagnose different pathologies. Furthermore, urea is seen in interstellar medium and its detection could yield valuable insight into the mechanisms governing star formation. Despite the prevalence of urea, an absence exists in recorded frequencies of this molecule. The new generation of the sub-millimeter telescopes, such as ALMA, HERSCHEL, and SOFIA, allows detection of interstellar molecular spectra at unprecedented spatial and spectral resolutions. The knowledge of the precise frequencies of spectra transitions present in interstellar molecular clouds would alleviate the problem of spectral congestion and aid in molecular identification. This paper reports the most recent investigation of the submillimeter/terahertz gas phase spectrum of urea. Up until now, only the microwave laboratory spectrum of urea's vibrational ground state has been available. This paper reports the high-resolution spectra of urea in the sub-millimeter range, and extends the spectroscopic assignment of the rotational transitions in the vibrational ground state. Additionally, the assignment of the first vibrational state and tentative assignments of two additional vibrational states have been made.

  10. A SUBMILLIMETER CONTINUUM SURVEY OF LOCAL DUST-OBSCURED GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong Chul [Korea Astronomy and Space Science Institute, 776 Daedeokdae-ro, Yuseong-gu, Daejeon 34055 (Korea, Republic of); Hwang, Ho Seong [School of Physics, Korea Institute for Advanced Study, 85 Hoegiro, Dongdaemun-gu, Seoul 02455 (Korea, Republic of); Lee, Gwang-Ho, E-mail: jclee@kasi.re.kr [Department of Physics and Astronomy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-742 (Korea, Republic of)

    2016-12-20

    We conduct a 350 μ m dust continuum emission survey of 17 dust-obscured galaxies (DOGs) at z = 0.05–0.08 with the Caltech Submillimeter Observatory (CSO). We detect 14 DOGs with S{sub 350μm} = 114–650 mJy and signal-to-noise > 3. By including two additional DOGs with submillimeter data in the literature, we are able to study dust content for a sample of 16 local DOGs, which consist of 12 bump and four power-law types. We determine their physical parameters with a two-component modified blackbody function model. The derived dust temperatures are in the range 57–122 K and 22–35 K for the warm and cold dust components, respectively. The total dust mass and the mass fraction of the warm dust component are 3–34 × 10{sup 7} M {sub ⊙} and 0.03%–2.52%, respectively. We compare these results with those of other submillimeter-detected infrared luminous galaxies. The bump DOGs, the majority of the DOG sample, show similar distributions of dust temperatures and total dust mass to the comparison sample. The power-law DOGs show a hint of smaller dust masses than other samples, but need to be tested with a larger sample. These findings support that the reason DOGs show heavy dust obscuration is not an overall amount of dust content, but probably the spatial distribution of dust therein.

  11. CHIMPS: the 13CO/C18O (J = 3 → 2) Heterodyne Inner Milky Way Plane Survey

    Science.gov (United States)

    Rigby, A. J.; Moore, T. J. T.; Plume, R.; Eden, D. J.; Urquhart, J. S.; Thompson, M. A.; Mottram, J. C.; Brunt, C. M.; Butner, H. M.; Dempsey, J. T.; Gibson, S. J.; Hatchell, J.; Jenness, T.; Kuno, N.; Longmore, S. N.; Morgan, L. K.; Polychroni, D.; Thomas, H.; White, G. J.; Zhu, M.

    2016-03-01

    We present the 13CO/C18O (J = 3 → 2) Heterodyne Inner Milky Way Plane Survey (CHIMPS) which has been carried out using the Heterodyne Array Receiver Program on the 15 m James Clerk Maxwell Telescope (JCMT) in Hawaii. The high-resolution spectral survey currently covers |b| ≤ 0.5° and 28° ≲ l ≲ 46°, with an angular resolution of 15 arcsec in 0.5 km s-1 velocity channels. The spectra have a median rms of ˜0.6 K at this resolution, and for optically thin gas at an excitation temperature of 10 K, this sensitivity corresponds to column densities of NH2 ˜ 3 × 1020 cm-2 and NH2 ˜ 4 × 1021 cm-2 for 13CO and C18O, respectively. The molecular gas that CHIMPS traces is at higher column densities and is also more optically thin than in other publicly available CO surveys due to its rarer isotopologues, and thus more representative of the three-dimensional structure of the clouds. The critical density of the J = 3 → 2 transition of CO is ≳104 cm-3 at temperatures of ≤20 K, and so the higher density gas associated with star formation is well traced. These data complement other existing Galactic plane surveys, especially the JCMT Galactic Plane Survey which has similar spatial resolution and column density sensitivity, and the Herschel infrared Galactic Plane Survey. In this paper, we discuss the observations, data reduction and characteristics of the survey, presenting integrated-emission maps for the region covered. Position-velocity diagrams allow comparison with Galactic structure models of the Milky Way, and while we find good agreement with a particular four-arm model, there are some significant deviations.

  12. Research Status and Action of Sub-millimeter Debris Impact Damage on Spacecraft Structure

    OpenAIRE

    Higashide, Masumi; Kurosaki, Hirohisa; Hasegawa, Sunao; 東出, 真澄; 黒崎, 裕久; 長谷川, 直

    2015-01-01

    To assess debris impact risk for the satellite, submillimeter debris impact damage has not been investigated enough to conduct satellite protective designing. JAXA is researching vulnerability of satellite structure materials against submillimeter debris impact, and proposing shielding methods. This report shows summary of submillimeter impact damages of honeycomb sandwich panels. The damage of the panel was investigated by hypervelocity impact experiments with the two-stage light gas gun in ...

  13. Laser-induced breakdown spectroscopy combined with spatial heterodyne spectroscopy.

    Science.gov (United States)

    Gornushkin, Igor B; Smith, Ben W; Panne, Ulrich; Omenetto, Nicoló

    2014-01-01

    A spatial heterodyne spectrometer (SHS) is tested for the first time in combination with laser-induced breakdown spectroscopy (LIBS). The spectrometer is a modified version of the Michelson interferometer in which mirrors are replaced by diffraction gratings. The SHS contains no moving parts and the gratings are fixed at equal distances from the beam splitter. The main advantage is high throughput, about 200 times higher than that of dispersive spectrometers used in LIBS. This makes LIBS-SHS a promising technique for low-light standoff applications. The output signal of the SHS is an interferogram that is Fourier-transformed to retrieve the original plasma spectrum. In this proof-of-principle study, we investigate the potential of LIBS-SHS for material classification and quantitative analysis. Brass standards with broadly varying concentrations of Cu and Zn were tested. Classification via principal component analysis (PCA) shows distinct groupings of materials according to their origin. The quantification via partial least squares regression (PLS) shows good precision (relative standard deviation < 10%) and accuracy (within ± 5% of nominal concentrations). It is possible that LIBS-SHS can be developed into a portable, inexpensive, rugged instrument for field applications.

  14. A simple and versatile phase detector for heterodyne interferometers.

    Science.gov (United States)

    Mlynek, A; Faugel, H; Eixenberger, H; Pautasso, G; Sellmair, G

    2017-02-01

    The measurement of the relative phase of two sinusoidal electrical signals is a frequently encountered task in heterodyne interferometry, but also occurs in many other applications. Especially in interferometry, multi-radian detectors are often required, which track the temporal evolution of the phase difference and are able to register phase changes that exceed 2π. While a large variety of solutions to this problem is already known, we present an alternative approach, which pre-processes the signals with simple analog circuitry and digitizes two resulting voltages with an analog-to-digital converter (ADC), whose sampling frequency can be far below the frequency of the sinusoidal signals. Phase reconstruction is finally carried out by software. The main advantage of this approach is its simplicity, using only few low-cost hardware components and a standard 2-channel ADC with low performance requirements. We present an application on the two-color interferometer of the ASDEX Upgrade tokamak, where the relative phase of 40 MHz sinusoids is measured.

  15. Observing Quantum State Diffusion by Heterodyne Detection of Fluorescence

    Directory of Open Access Journals (Sweden)

    P. Campagne-Ibarcq

    2016-01-01

    Full Text Available A qubit can relax by fluorescence, which prompts the release of a photon into its electromagnetic environment. By counting the emitted photons, discrete quantum jumps of the qubit state can be observed. The succession of states occupied by the qubit in a single experiment, its quantum trajectory, depends in fact on the kind of detector. How are the quantum trajectories modified if one measures continuously the amplitude of the fluorescence field instead? Using a superconducting parametric amplifier, we perform heterodyne detection of the fluorescence of a superconducting qubit. For each realization of the measurement record, we can reconstruct a different quantum trajectory for the qubit. The observed evolution obeys quantum state diffusion, which is characteristic of quantum measurements subject to zero-point fluctuations. Independent projective measurements of the qubit at various times provide a quantitative verification of the reconstructed trajectories. By exploring the statistics of quantum trajectories, we demonstrate that the qubit states span a deterministic surface in the Bloch sphere at each time in the evolution. Additionally, we show that when monitoring fluorescence field quadratures, coherent superpositions are generated during the decay from excited to ground state. Counterintuitively, measuring light emitted during relaxation can give rise to trajectories with increased excitation probability.

  16. Ground based mid-IR heterodyne spectrometer concept for planetary atmospheres observations

    Science.gov (United States)

    Garamov, V.; Benderov, O.; Semenov, V.; Spiridonov, M.; Rodin, A.; Stepanov, B.

    2017-09-01

    We present a heterodyne spectrometer concept based on distributed feedback (DFB) quantum cascade lasers (QCL) operated in midle infrared region (MIR). The instrument is assumed to be mount on the Russian infrared observatories. The core features of the concept are compact design, utilizing a novel mid-IR fiber optical components and dynamic local oscillator frequency locking using reference molecule absorption line. The instrument characteristics are similar to modern heterodyne devices THIS (Cologne University, Germany) and MILAHI (Tohoku University, Japan) in terms of fundamental parameters, including spectral resolution, spectral coverage in a single observation. At present moment we created laboratory setup including all necessary elements of MIR heterodyne spectrometer. We have studied different components of noises of our system and found optimal value of LO power. The measured signal to noise ratio (SNR) with MCT PD was about 10 times greater than LO's shot noise (theoretical limit of heterodyne technique SNR) and limited by QCL relative intensity noise (RIN). However, applying additional filtering it is possible to reduce this value better than 5 shot noise level, which is typical to TEC cooled MCT PD. Also we demonstrate heterodyne signal measurements using laboratory black body with temperature of 400 oC.

  17. Performance simulation of heterodyne synchronous receiving system in coherent optical communication

    Science.gov (United States)

    Zheng, BaiChao; Tong, ShouFeng

    2015-03-01

    Coherent optical communication technology is currently a hotpot research of communication. Coherent optical communication heterodyne synchronous receiving system is researched. The basic principle of coherent optical communication is introduced in briefly, the heterodyne synchronous receiving system is established in the basis of the principle. A simulation model, charactered as Synchronous receiving system of Coherent Heterodyne, was rightly set up. In addition, with regarding actual device parameters as reference, and under the situation of 2.5Gbps communication rate and 10km as communication distance, Optisystem was operating to accomplish simulation analysis for capacity of this system in different signal-radiation rate and distinguish weather condition. The consequence of simulation demonstrated: as the receiving sensitivity is relatively high when compared communication system of coherent heterodyne to that of IM/DD, the coherent optical communication system has lower requirement to signal rate of radiated laser in the same condition. Consequently, it can be concluded that coherent heterodyne system has high receiving sensitivity, and strong capacity of resisting disturbance, moreover it is appropriately communicated in channel with relatively high disturbance, it possesses great advantages to IM/DD method in atmosphere channel which has strong disturbance.

  18. Superconductor Semiconductor Research for NASA's Submillimeter Wavelength Missions

    Science.gov (United States)

    Crowe, Thomas W.

    1997-01-01

    Wideband, coherent submillimeter wavelength detectors of the highest sensitivity are essential for the success of NASA's future radio astronomical and atmospheric space missions. The critical receiver components which need to be developed are ultra- wideband mixers and suitable local oscillator sources. This research is focused on two topics, (1) the development of reliable varactor diodes that will generate the required output power for NASA missions in the frequency range from 300 GHZ through 2.5 THz, and (2) the development of wideband superconductive mixer elements for the same frequency range.

  19. Solar Science with the Atacama Large Millimeter/Submillimeter Array—A New View of Our Sun

    Science.gov (United States)

    Wedemeyer, S.; Bastian, T.; Brajša, R.; Hudson, H.; Fleishman, G.; Loukitcheva, M.; Fleck, B.; Kontar, E. P.; De Pontieu, B.; Yagoubov, P.; Tiwari, S. K.; Soler, R.; Black, J. H.; Antolin, P.; Scullion, E.; Gunár, S.; Labrosse, N.; Ludwig, H.-G.; Benz, A. O.; White, S. M.; Hauschildt, P.; Doyle, J. G.; Nakariakov, V. M.; Ayres, T.; Heinzel, P.; Karlicky, M.; Van Doorsselaere, T.; Gary, D.; Alissandrakis, C. E.; Nindos, A.; Solanki, S. K.; Rouppe van der Voort, L.; Shimojo, M.; Kato, Y.; Zaqarashvili, T.; Perez, E.; Selhorst, C. L.; Barta, M.

    2016-04-01

    The Atacama Large Millimeter/submillimeter Array (ALMA) is a new powerful tool for observing the Sun at high spatial, temporal, and spectral resolution. These capabilities can address a broad range of fundamental scientific questions in solar physics. The radiation observed by ALMA originates mostly from the chromosphere—a complex and dynamic region between the photosphere and corona, which plays a crucial role in the transport of energy and matter and, ultimately, the heating of the outer layers of the solar atmosphere. Based on first solar test observations, strategies for regular solar campaigns are currently being developed. State-of-the-art numerical simulations of the solar atmosphere and modeling of instrumental effects can help constrain and optimize future observing modes for ALMA. Here we present a short technical description of ALMA and an overview of past efforts and future possibilities for solar observations at submillimeter and millimeter wavelengths. In addition, selected numerical simulations and observations at other wavelengths demonstrate ALMA's scientific potential for studying the Sun for a large range of science cases.

  20. Thousand-Element Multiplexed Superconducting Bolometer Arrays

    Science.gov (United States)

    Benford, Dominic; Chervenak, Jay; Voellmer, George; Staguhn, Johannes; Shafer, Rick; Stacey, Gordon; Irwin, Kent

    Large format, two-dimensional arrays of close-packed bolometers will enable submillimeter cameras and spectrometers to obtain images and spectra orders of magnitude faster than present instruments. The South Pole Imaging Fabry-Perot Interferometer (SPIFI) for the AST/RO observatory and the Submillimeter and Far-InfraRed Experiment (SAFIRE) on the SOFIA airborne observatory will employ a large-format, two-dimensional, close-packed bolometer arrays. Both these instruments are imaging Fabry-Perot spectrometers operating at wavelengths between 100μm and 700μm. The array format is 16x32 pixels, using a 32-element multiplexer developed in part for this purpose. The low backgrounds achieved in spectroscopy require very sensitive detectors with NEPs of order 5x10-18 W/Hz1/2. Superconducting detectors can be close-packed using the Pop-Up Detector (PUD) format, and SQUID multiplexers operating at the detector bas temperature can be intimately coupled to them. We are fabricating an engineering model array with this technology which features a very compact, modular approach for large format arrays.

  1. Heterodyne detection at 300 GHz using neon indicator lamp glow discharge detector.

    Science.gov (United States)

    Aharon Akram, Avihai; Rozban, Daniel; Kopeika, Natan S; Abramovich, Amir

    2013-06-10

    A miniature neon indicator lamp, also known as a glow discharge detector (GDD), costing about 50 cents, was found to be an excellent room temperature terahertz radiation detector. Proof-of-concept 300 GHz heterodyne detection using GDD is demonstrated in this paper. Furthermore, a comparison to direct detection was carried out as well. Previous results with the GDD at 10 GHz showed 40 times better sensitivity using heterodyne detection compared to direct detection. Preliminary results at 300 GHz showed better sensitivity by a factor of 20 with only 56 μW local-oscillator power using heterodyne compared to direct detection. The higher the local-oscillator power (P(lo)), the better the sensitivity of the detector. Further improvement can be achieved by employing better quasi-optical design.

  2. Properties of Submillimeter Galaxies in the CANDELS GOODS-South Field

    NARCIS (Netherlands)

    Wiklind, Tommy; Conselice, Christopher J.; Dahlen, Tomas; Dickinson, Mark E.; Ferguson, Henry C.; Grogin, Norman A.; Guo, Yicheng; Koekemoer, Anton M.; Mobasher, Bahram; Mortlock, Alice; Fontana, Adriano; Davé, Romeel; Yan, Haojing; Acquaviva, Viviana; Ashby, Matthew L. N.; Barro, Guillermo; Caputi, Karina I.; Castellano, Marco; Dekel, Avishai; Donley, Jennifer L.; Fazio, Giovanni G.; Giavalisco, Mauro; Grazian, Andrea; Hathi, Nimish P.; Kurczynski, Peter; Lu, Yu; McGrath, Elizabeth J.; de Mello, Duilia F.; Peth, Michael; Safarzadeh, Mohammad; Stefanon, Mauro; Targett, Thomas

    We derive physical properties of 10 submillimeter galaxies located in the CANDELS coverage of the GOODS-S field. The galaxies were first identified as submillimeter sources with the LABOCA bolometer and subsequently targeted for 870 μm continuum observation with ALMA. The high angular resolution of

  3. InP HEMT Integrated Circuits for Submillimeter Wave Radiometers in Earth Remote Sensing

    Science.gov (United States)

    Deal, William R.; Chattopadhyay, Goutam

    2012-01-01

    The operating frequency of InP integrated circuits has pushed well into the Submillimeter Wave frequency band, with amplification reported as high as 670 GHz. This paper provides an overview of current performance and potential application of InP HEMT to Submillimeter Wave radiometers for earth remote sensing.

  4. Josephson frequency meter for millimeter and submillimeter wavelengths

    Energy Technology Data Exchange (ETDEWEB)

    Anischenko, S.E.; Larkin, S.Y.; Chaikovsky, V.I. [State Research Center, Kiev (Ukraine)] [and others

    1994-12-31

    Frequency measurements of electromagnetic oscillations of millimeter and submillimeter wavebands with frequency growth due to a number of reasons become more and more difficult. First, these frequencies are considered to be cutoff for semiconductor converting devices and one has to use optical measurement methods instead of traditional ones with frequency transfer. Second, resonance measurement methods are characterized by using relatively narrow bands and optical ones are limited in frequency and time resolution due to the limited range and velocity of movement of their mechanical elements as well as the efficiency of these optical techniques decreases with the increase of wavelength due to diffraction losses. That requires the apriori information on the radiation frequency band of the source involved. Method of measuring frequency of harmonic microwave signals in millimeter and submillimeter wavebands based on the ac Josephson effect in superconducting contacts is devoid of all the above drawbacks. This approach offers a number of major advantages over the more traditional measurement methods, that is the one based on frequency conversion, resonance and interferrometric techniques. It can be characterized by high potential accuracy, wide range of frequencies measured, prompt measurement and the opportunity to obtain panoramic display of the results as well as full automation of the measuring process.

  5. A Sub-millimeter, Inductively Powered Neural Stimulator

    Directory of Open Access Journals (Sweden)

    Daniel K. Freeman

    2017-11-01

    Full Text Available Wireless neural stimulators are being developed to address problems associated with traditional lead-based implants. However, designing wireless stimulators on the sub-millimeter scale (<1 mm3 is challenging. As device size shrinks, it becomes difficult to deliver sufficient wireless power to operate the device. Here, we present a sub-millimeter, inductively powered neural stimulator consisting only of a coil to receive power, a capacitor to tune the resonant frequency of the receiver, and a diode to rectify the radio-frequency signal to produce neural excitation. By replacing any complex receiver circuitry with a simple rectifier, we have reduced the required voltage levels that are needed to operate the device from 0.5 to 1 V (e.g., for CMOS to ~0.25–0.5 V. This reduced voltage allows the use of smaller receive antennas for power, resulting in a device volume of 0.3–0.5 mm3. The device was encapsulated in epoxy, and successfully passed accelerated lifetime tests in 80°C saline for 2 weeks. We demonstrate a basic proof-of-concept using stimulation with tens of microamps of current delivered to the sciatic nerve in rat to produce a motor response.

  6. Structured Antireflective Coating for Silicon at Submillimeter Frequencies

    Science.gov (United States)

    Padilla, Estefania

    2018-01-01

    Observations at millimeter and submillimeter wavelengths are useful for many astronomical studies, such as the polarization of the cosmic microwave background or the formation and evolution of galaxy clusters. In order to allow observations over a broad spectral bandwidth (approximatively from 70 to 420 GHz), innovative broadband anti-reflective (AR) optics must be utilized in submillimeter telescopes. Due to its low loss and high refractive index, silicon is a fine optical material at these frequencies, but an AR coating with multiple layers is required to maximize its transmission over a wide bandwidth. Structured multilayer AR coatings for silicon are currently being developed at Caltech and JPL. The development process includes the design of the structured layers with commercial electromagnetic simulation software, the fabrication by using deep reactive ion etching, and the test of the transmission and reflection of the patterned wafers. Geometrical 3D patterns have successfully been etched at the surface of the silicon wafers creating up to 2 layers with different effective refractive indices. The transmission and reflection of single AR layer wafers, measured between 75 and 330 GHz, are close to the simulation predictions. These results allow the development of new designs with 5 or 6 AR layers in order to improve the bandwidth and transmission of the silicon AR coatings.

  7. Methods, compositions and kits for imaging cells and tissues using nanoparticles and spatial frequency heterodyne imaging

    Science.gov (United States)

    Rose-Petruck, Christoph; Wands, Jack R.; Rand, Danielle; Derdak, Zoltan; Ortiz, Vivian

    2016-04-19

    Methods, compositions, systems, devices and kits are provided herein for preparing and using a nanoparticle composition and spatial frequency heterodyne imaging for visualizing cells or tissues. In various embodiments, the nanoparticle composition includes at least one of: a nanoparticle, a polymer layer, and a binding agent, such that the polymer layer coats the nanoparticle and is for example a polyethylene glycol, a polyelectrolyte, an anionic polymer, or a cationic polymer, and such that the binding agent that specifically binds the cells or the tissue. Methods, compositions, systems, devices and kits are provided for identifying potential therapeutic agents in a model using the nanoparticle composition and spatial frequency heterodyne imaging.

  8. Usefulness of the infrared heterodyne radiometer in remote sensing of atmospheric pollutants.

    Science.gov (United States)

    Menzies, R. T.; Shumate, M. S.

    1971-01-01

    The application of narrow-band optical receivers to the problem of sensing atmospheric pollution is discussed. The emission/absorption lines of many major atmospheric pollutant molecules overlap the operating frequency bands of CO2 laser and CO laser heterodyne receivers. Several remote pollution sensing systems which are based upon utilization of these spectral overlaps are described, and an analysis of their potential is presented. The possibility of using other lasers (e.g.: the PbSnTe tunable diode laser) as local oscillators is also considered. Results of laboratory experiments with a CO2 laser heterodyne radiometer are presented.

  9. Speckle decorrelation in Ultrasound-modulated optical tomography made by heterodyne holography

    CERN Document Server

    Gross, M

    2016-01-01

    Ultrasound-modulated optical tomography (UOT) is a technique that images optical contrast deep inside scattering media. Heterodyne holography is a promising tool able to detect the UOT tagged photons with high efficiency. In this work, we describe theoretically the detection of the tagged photon in heterodyne holography based UOT, show how to filter the untagged photon discuss, and discuss the effect of speckle decorrelation. We show that optimal detection sensitivity can obtain, if the frame exposure time is of the order of the decorrelation time.

  10. Compact Receiver Front Ends for Submillimeter-Wave Applications

    Science.gov (United States)

    Mehdi, Imran; Chattopadhyay, Goutam; Schlecht, Erich T.; Lin, Robert H.; Sin, Seth; Peralta, Alejandro; Lee, Choonsup; Gill, John J.; Gulkis, Samuel; Thomas, Bertrand C.

    2012-01-01

    The current generation of submillimeter-wave instruments is relatively mass and power-hungry. The receiver front ends (RFEs) of a submillimeter instrument form the heart of the instrument, and any mass reduction achieved in this subsystem is propagated through the instrument. In the current implementation, the RFE consists of different blocks for the mixer and LO circuits. The motivation for this work is to reduce the mass of the RFE by integrating the mixer and LO circuits in one waveguide block. The mixer and its associated LO chips will all be packaged in a single waveguide package. This will reduce the mass of the RFE and also provide a number of other advantages. By bringing the mixer and LO circuits close together, losses in the waveguide will be reduced. Moreover, the compact nature of the block will allow for better thermal control of the block, which is important in order to reduce gain fluctuations. A single waveguide block with a 600- GHz RFE functionality (based on a subharmonically pumped Schottky diode pair) has been demonstrated. The block is about 3x3x3 cubic centimeters. The block combines the mixer and multiplier chip in a single package. 3D electromagnetic simulations were carried out to design the waveguide circuit around the mixer and multiplier chip. The circuit is optimized to provide maximum output power and maximum bandwidth. An integrated submillimeter front end featuring a 520-600-GHz sub-harmonic mixer and a 260-300-GHz frequency tripler in a single cavity was tested. Both devices used GaAs MMIC membrane planar Schottky diode technology. The sub-harmonic mixer/tripler circuit has been tested using conventional metal-machined blocks. Measurement results on the metal block give best DSB (double sideband) mixer noise temperature of 2,360 K and conversion losses of 7.7 dB at 520 GHz. The LO input power required to pump the integrated tripler/sub-harmonic mixer is between 30 and 50 mW.

  11. Micro-Spec: an Integrated, Direct-Detection Spectrometer for Far-Infrared and Submillimeter Astronomy

    Science.gov (United States)

    Cataldo, Giuseppe

    2014-01-01

    The far-infrared and submillimeter portions of the electromagnetic spectrum provide a unique view of the astrophysical processes present in the early universe. Our ability to fully explore this rich spectral region has been limited, however, by the size and cost of the cryogenic spectrometers required to carry out such measurements. Micro-Spec (u-Spec) is a high-sensitivity, direct-detection spectrometer concept working in the 450-1000 micromillimeter wavelength range which will enable a wide range of flight missions that would otherwise be challenging due to the large size of current instruments with the required spectral resolution and sensitivity. The spectrometer design utilizes two internal antenna arrays, one for transmitting and one for receiving, superconducting microstrip transmission lines for power division and phase delay, and an array of microwave kinetic inductance detectors (MKIDs) to achieve these goals. The instrument will be integrated on a approximately 10 square cm silicon chip and can therefore become an important capability under the low background conditions accessible via space and high-altitude borne platforms. In this paper, an optical design methodology for Micro-Spec is presented, with particular attention given to its twodimensional diffractive region, where the light of different wavelengths is focused on the different detectors. The method is based on the maximization of the instrument resolving power and minimization of the RMS phase error on the instrument focal plane. This two-step optimization can generate geometrical configurations given specific requirements on spectrometer size, operating spectral range and performance. A point design with resolving power of 257, an RMS phase error less than 0.1 radians and four stigmatic points was developed for initial demonstration and will be the basis of future instruments with resolving power up to about 1200.

  12. Transition-Edge Hot-Electron Microbolometers for Millimeter and Submillimeter Astrophysics

    Science.gov (United States)

    Hsieh, Wen-Ting; Stevenson, Thomas; U-yen, Kongpop; Wollack, Edward; Barrentine, Emily

    2014-01-01

    The millimeter and the submillimeter wavelengths of the electromagnetic spectrum hold a wealth of information about the evolution of the universe. In particular, cosmic microwave background (CMB) radiation and its polarization carry the oldest information in the universe, and provide the best test of the inflationary paradigm available to astronomy today. Detecting gravity waves through their imprint on the CMB polarization would have extraordinary repercussions for cosmology and physics. A transition-edge hot-electron micro - bolometer (THM) consists of a superconducting bilayer transition-edge sensor (TES) with a thin-film absorber. Unlike traditional monolithic bolometers that make use of micromachined structures, the THM em ploys the decoupling between electrons and phonons at millikelvin temperatures to provide thermal isolation. The devices are fabricated photolithographically and are easily integrated with antennas via microstrip transmission lines, and with SQUID (superconducting quantum interference device) readouts. The small volume of the absorber and TES produces a short thermal time constant that facilitates rapid sky scanning. The THM consists of a thin-film metal absorber overlapping a superconducting TES. The absorber forms the termination of a superconducting microstripline that carries RF power from an antenna. The purpose of forming a separate absorber and TES is to allow flexibility in the optimization of the two components. In particular, the absorbing film's impedance can be chosen to match the antenna, while the TES impedance can be chosen to match to the readout SQUID amplifier. This scheme combines the advantages of the TES with the advantages of planar millimeter-wave transmission line circuits. Antenna-coupling to the detectors via planar transmission lines allows the detector dimensions to be much smaller than a wavelength, so the technique can be extended across the entire microwave, millimeter, and submillimeter wavelength ranges. The

  13. Characterizing thawing permafrost with the Miniaturized Laser Heterodyne Radiometer (mini-LHR) through column measurements of methane

    Science.gov (United States)

    Wilson, E. L.; DiGregorio, A.

    2015-12-01

    We present mini-LHR measurements of column CH4 from our preliminary field campaign outside of Fairbanks, AK in June 2015. The mini-LHR is fully automated and works in tandem with the AERONET sun photometer for collection of column CH4 every 15 minutes. As part of a comprehensive array of ground based instruments, measurements made by the mini-LHR will aid in monitoring of changes in atmospheric greenhouse gas emissions and help interpret data collected by space-born instruments. The mini-LHR is a passive variation of typical heterodyne radiometry instruments, using sunlight as the light source for measuring CH4 in the infrared. Collecting through collimation optics mounted on the AERONET tracker, the sunlight is chopped in an optical chopper and mixed with a local oscillator in a fast photoreciever (InGaAs detector). The amplitude of the resultant RF (radio frequency) beat signal directly correlates with the concentration of the column gas being measured. Working in conjunction with ground penetrating radar, covariance flux tower, and high-resolution surface CO2 and CH4 measurements, our column CH4 measurements contribute to a holistic view of the atmospheric evolution and response to permafrost thaw. With the intent to expand our observational network to other North American sites, our column CH4 measurements will be instrumental in showing the effects of permafrost thaw on global CH4 levels, as well as benefiting ongoing efforts in retrospective and predictive simulations of greenhouse gasses.

  14. Multipass millimeter/submillimeter spectrometer to probe dissociative reaction dynamics.

    Science.gov (United States)

    Laas, Jacob C; Hays, Brian M; Widicus Weaver, Susanna L

    2013-10-03

    We present here the instrument design and first experimental results from a multipass millimeter/submillimeter spectrometer designed to probe dissociative reaction dynamics. This work focuses on benchmarking the instrument performance through detection of the CH3O and H2CO products from methanol dissociation induced by a high-voltage plasma discharge. Multiple rotational lines from CH3O and H2CO were observed when this plasma discharge was applied to a sample of methanol vapor seeded in an argon supersonic expansion. The rotational temperature of the dissociation products and their abundance with respect to methanol were determined using a Boltzmann analysis. The minimum detectable absorption coefficient for this instrument was determined to be αmin ≤ 5 × 10(-9) cm(-1). We discuss these results in the context of future applications of this instrument to the study of photodissociation branching ratios for small organic molecules that are important in complex interstellar chemistry.

  15. The role of THz and submillimeter wave technology in DHS

    Science.gov (United States)

    Coty, Thomas; Fuller-Tedeschi, Anna

    2011-06-01

    THz and submillimeter wave technology is of great interest to DHS S&T due to the non-ionizing and clothing penetrating properties of the spectral region. Imaging in the region allows for standoff imaging of concealed threats such as Improvised Explosive Devices (IED) at operationally relevant distances. DHS S&T is investing in this area with the development of components such as detectors and sources for active imaging as well as full sensor systems in the future. The fundamental characterization of the region is also being explored with DHS funding by imaging well-characterized rough surface scattering targets. Analysis of these images will yield data to be used in evaluating assumptions currently made in current performance models. This along with the relevant field applications will be addressed.

  16. Terahertz heterodyne mixing with a hot electron bolometer and a quantum cascade laser

    NARCIS (Netherlands)

    Hajenius, M.

    2007-01-01

    Heterodyne measurements in the frequency range between 1 - 6 terahertz (THz) are expected to provide a wealth of information on questions ranging from the formation of new stars and the conditions under which life formed on our own planet to the ozone hole in our own atmosphere. Hot electron

  17. Complete Two-dimensional Muellermetric Imaging of Biological Tissue Using Heterodyned Optical Coherence Tomography

    CERN Document Server

    Liu, Xue; Shahriar, M S

    2010-01-01

    A polarization-sensitive optical coherence tomography system based on heterodyning and filtering techniques is built to perform Stokesmetric imaging of different layers of depths in a porcine tendon sample. The complete 4\\times4 backscattering Muellermetric images of one layer are acquired using such a system. The images reveal information indiscernible from a conventional OCT system.

  18. High-resolution heterodyne spectroscopy using a tunable quantum cascade laser around 3.5 THz

    NARCIS (Netherlands)

    Ren, Y.; Hovenier, J.N.; Higgins, R.; Gao, J.R.; Klapwijk, T.M.; Shi, S.C.; Klein, B.; Kao, T.Y.; Hu, Q.; Reno, J.L.

    2011-01-01

    A frequency tunable terahertz heterodyne spectrometer, based on a third-order distributed feedback quantum cascade laser as a local oscillator, has been demonstrated by measuring molecular spectral lines of methanol (CH3OH) gas at 3.5 THz. By varying the bias voltage of the laser, we achieved a

  19. Hydrogen-bond dynamics in water explored by heterodyne-detected photon echo

    NARCIS (Netherlands)

    Yeremenko, S; Pshenichnikov, MS; Wiersma, DA; Pshenichnikov, Maxim S.

    2003-01-01

    Results of heterodyne-detected photon echo experiments on the OH stretching mode of water are reported and discussed. Two vibrational dynamical processes with time constants of 130 and 900 fs were identified. The former is attributed to bond breaking dynamics of a single hydrogen bond, the latter to

  20. SUBMILLIMETER FOLLOW-UP OF WISE-SELECTED HYPERLUMINOUS GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Wu Jingwen; Eisenhardt, Peter R. M.; Stern, Daniel; Assef, Roberto [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Tsai, Chao-Wei; Cutri, Roc; Griffith, Roger; Jarrett, Thomas [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Sayers, Jack; Bridge, Carrie [Division of Physics, Math and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Benford, Dominic [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Blain, Andrew [Department of Physics and Astronomy, University of Leicester, LE1 7RH Leicester (United Kingdom); Petty, Sara; Lake, Sean [Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA 90095 (United States); Bussmann, Shane [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS78, Cambridge, MA 02138 (United States); Comerford, Julia M.; Evans, Neal J. II [Department of Astronomy, University of Texas, Austin, TX 78731 (United States); Lonsdale, Carol [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Rho, Jeonghee [SETI Institute, 189 BERNARDO Avenue, Mountain View, CA 94043 (United States); Stanford, S. Adam, E-mail: jingwen.wu@jpl.nasa.gov [Department of Physics, University of California Davis, One Shields Avenue, Davis, CA 95616 (United States); and others

    2012-09-01

    We have used the Caltech Submillimeter Observatory (CSO) to follow-up a sample of Wide-field Infrared Survey Explorer (WISE) selected, hyperluminous galaxies, the so-called W1W2-dropout galaxies. This is a rare ({approx}1000 all-sky) population of galaxies at high redshift (peaks at z = 2-3), which are faint or undetected by WISE at 3.4 and 4.6 {mu}m, yet are clearly detected at 12 and 22 {mu}m. The optical spectra of most of these galaxies show significant active galactic nucleus activity. We observed 14 high-redshift (z > 1.7) W1W2-dropout galaxies with SHARC-II at 350-850 {mu}m, with nine detections, and observed 18 with Bolocam at 1.1 mm, with five detections. Warm Spitzer follow-up of 25 targets at 3.6 and 4.5 {mu}m, as well as optical spectra of 12 targets, are also presented in the paper. Combining WISE data with observations from warm Spitzer and CSO, we constructed their mid-IR to millimeter spectral energy distributions (SEDs). These SEDs have a consistent shape, showing significantly higher mid-IR to submillimeter ratios than other galaxy templates, suggesting a hotter dust temperature. We estimate their dust temperatures to be 60-120 K using a single-temperature model. Their infrared luminosities are well over 10{sup 13} L{sub Sun }. These SEDs are not well fitted with existing galaxy templates, suggesting they are a new population with very high luminosity and hot dust. They are likely among the most luminous galaxies in the universe. We argue that they are extreme cases of luminous, hot dust-obscured galaxies (DOGs), possibly representing a short evolutionary phase during galaxy merging and evolution. A better understanding of their long-wavelength properties needs ALMA as well as Herschel data.

  1. Fast Fourier transform spectrometer readout for large arrays of microwave kinetic inductance detectors

    NARCIS (Netherlands)

    Yates, S. J. C.; Baryshev, A. M.; Baselmans, J. J. A.; Klein, B.; Guesten, R.

    2009-01-01

    Microwave kinetic inductance detectors have great potential for large, very sensitive detector arrays for use in, for example, submillimeter imaging. Being intrinsically readout in the frequency domain, they are particularly suited for frequency domain multiplexing allowing similar to 1000 s of

  2. Superconducting Resonator Spectrometer for Millimeter- and Submillimeter-Wave Astrophysics Project

    Data.gov (United States)

    National Aeronautics and Space Administration — "We propose to develop a novel ultra-compact spectrograph-on-a-chip for the submillimeter and millimeter waveband. SuperSpec uses planar lithographed superconducting...

  3. THE SCUBA-2 COSMOLOGY LEGACY SURVEY: MULTIWAVELENGTH COUNTERPARTS TO 10{sup 3} SUBMILLIMETER GALAXIES IN THE UKIDSS-UDS FIELD

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chian-Chou; Smail, Ian; Ma, Cheng-Jiun; Simpson, James M.; Swinbank, A. Mark [Centre for Extragalactic Astronomy, Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom); Ivison, Rob J.; Arumugam, Vinodiran; Mortlock, Alice; Dunlop, James S.; Michałowski, Michał J. [Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Almaini, Omar; Conselice, Christopher J.; Hartley, Will G. [University of Nottingham, School of Physics and Astronomy, Nottingham, NG7 2RD (United Kingdom); Geach, James E. [Center for Astrophysics Research, Science and Technology Research Institute, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom); Simpson, Chris [Astrophysics Research Institute, Liverpool John Moores University, Liverpool Science Park, 146 Brownlow Hill, Liverpool L3 5RF (United Kingdom); Aretxaga, Itziar [Instituto Nacional de Astrofísica, Óptica y Electrónica (INAOE), Luis Enrique Erro 1, Sta. Ma. Tonantzintla, Puebla (Mexico); Blain, Andrew [Physics and Astronomy, University of Leicester, Leicester, LE1 7RH (United Kingdom); Chapman, Scott C. [Department of Physics and Atmospheric Science, Dalhousie University, 6310 Coburg Road, Halifax, NS B3H 4R2 (Canada); Farrah, Duncan [Department of Physics, Virginia Tech, Blacksburg, VA 24061 (United States); Halpern, Mark [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); and others

    2016-04-01

    We present multiwavelength identifications for the counterparts of 1088 submillimeter sources detected at 850 μm in the SCUBA-2 Cosmology Legacy Survey study of the UKIRT Infrared Deep Sky Survey-Ultra-Deep Survey (UDS) field. By utilizing an Atacama Large Millimeter Array (ALMA) pilot study on a subset of our bright SCUBA-2 sample as a training set, along with the deep optical–near-infrared (OIR) data available in this field, we develop a novel technique, Optical–IR Triple Color (OIRTC), using z − K, K − [3.6], [3.6] − [4.5] colors to select the candidate submillimeter galaxy (SMG) counterparts. By combining radio identification and the OIRTC technique, we find counterpart candidates for 80% of the Class = 1 ≥ 4σ SCUBA-2 sample, defined as those that are covered by both radio and OIR imaging and the base sample for our scientific analyses. Based on the ALMA training set, we expect the accuracy of these identifications to be 82% ± 20%, with a completeness of 69% ± 16%, essentially as accurate as the traditional p-value technique but with higher completeness. We find that the fraction of SCUBA-2 sources having candidate counterparts is lower for fainter 850 μm sources, and we argue that for follow-up observations sensitive to SMGs with S{sub 850} ≳ 1 mJy across the whole ALMA beam, the fraction with multiple counterparts is likely to be >40% for SCUBA-2 sources at S{sub 850} ≳ 4 mJy. We find that the photometric redshift distribution for the SMGs is well fit by a lognormal distribution, with a median redshift of z = 2.3 ± 0.1. After accounting for the sources without any radio and/or OIRTC counterpart, we estimate the median redshift to be z = 2.6 ± 0.1 for SMGs with S{sub 850} > 1 mJy. We also use this new large sample to study the clustering of SMGs and the far-infrared properties of the unidentified submillimeter sources by stacking their Herschel SPIRE far-infrared emission.

  4. EVIDENCE FOR ENVIRONMENTAL CHANGES IN THE SUBMILLIMETER DUST OPACITY

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Peter G.; Roy, Arabindo; Miville-Deschenes, Marc-Antoine [Canadian Institute for Theoretical Astrophysics, University of Toronto, 60 St. George Street, Toronto, ON M5S 3H8 (Canada); Bontemps, Sylvain [Observatoire de Bordeaux, BP 89, F-33270 Floirac (France); Ade, Peter A. R.; Griffin, Matthew; Hargrave, Peter C.; Mauskopf, Philip [Department of Physics and Astronomy, Cardiff University, 5 The Parade, Cardiff, CF24 3AA (United Kingdom); Bock, James J. [Jet Propulsion Laboratory, Pasadena, CA 91109-8099 (United States); Chapin, Edward L.; Halpern, Mark; Marsden, Gaelen [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); Devlin, Mark J.; Dicker, Simon R.; Klein, Jeff [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104 (United States); Gundersen, Joshua O. [Department of Physics, University of Miami, 1320 Campo Sano Drive, Carol Gables, FL 33146 (United States); Hughes, David H. [Instituto Nacional de Astrofisica Optica y Electronica (INAOE), Aptdo. Postal 51 y 72000 Puebla (Mexico); Netterfield, Calvin B. [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada); Olmi, Luca [INAF, Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 (Italy); Patanchon, Guillaume [Laboratoire APC, 10, rue Alice Domon et Leonie Duquet F-75205 Paris (France); and others

    2012-05-20

    The submillimeter opacity of dust in the diffuse interstellar medium (ISM) in the Galactic plane has been quantified using a pixel-by-pixel correlation of images of continuum emission with a proxy for column density. We used multi-wavelength continuum data: three Balloon-borne Large Aperture Submillimeter Telescope bands at 250, 350, and 500 {mu}m and one IRAS band at 100 {mu}m. The proxy is the near-infrared color excess, E(J - K{sub s}), obtained from the Two Micron All Sky Survey. Based on observations of stars, we show how well this color excess is correlated with the total hydrogen column density for regions of moderate extinction. The ratio of emission to column density, the emissivity, is then known from the correlations, as a function of frequency. The spectral distribution of this emissivity can be fit by a modified blackbody, whence the characteristic dust temperature T and the desired opacity {sigma}{sub e}(1200) at 1200 GHz or 250 {mu}m can be obtained. We have analyzed 14 regions near the Galactic plane toward the Vela molecular cloud, mostly selected to avoid regions of high column density (N{sub H} > 10{sup 22} cm{sup -2}) and small enough to ensure a uniform dust temperature. We find {sigma}{sub e}(1200) is typically (2-4) Multiplication-Sign 10{sup -25} cm{sup 2} H{sup -1} and thus about 2-4 times larger than the average value in the local high Galactic latitude diffuse atomic ISM. This is strong evidence for grain evolution. There is a range in total power per H nucleon absorbed (and re-radiated) by the dust, reflecting changes in the strength of the interstellar radiation field and/or the dust absorption opacity. These changes in emission opacity and power affect the equilibrium T, which is typically 15 K, colder than at high latitudes. Our analysis extends, to higher opacity and lower temperature, the trend of increasing {sigma}{sub e}(1200) with decreasing T that was found at high latitudes. The recognition of changes in the emission opacity

  5. Double-heterodyne-interferometry with delay-lines larger than coherence length of the laser light used

    Science.gov (United States)

    Hofbauer, Ulrich; Dalhoff, Ernst; Tiziani, Hans

    1999-04-01

    A double-heterodyne-interferometer (DHI) was realized with a laser diode as light source and a 500-MHz acoustooptical modulator (AOM). We show that measurements of the phase between the two heterodyne signals at optical path differences (OPD) up to 3.25 km, which is more than 350 times the coherence length of the laser light used, are possible. By measurements with this delay line, a distance resolution of 0.14 mm was obtained.

  6. Detection of Submillimeter-wave [C i] Emission in Gaseous Debris Disks of 49 Ceti and β Pictoris

    Energy Technology Data Exchange (ETDEWEB)

    Higuchi, Aya E.; Sakai, Nami [The Institute of Physical and Chemical Research (RIKEN), 2-1, Hirosawa, Wako-shi, Saitama 351-0198 (Japan); Sato, Aki; Tsukagoshi, Takashi; Momose, Munetake [College of Science, Ibaraki University, Bunkyo 2-1-1, Mito 310-8512 (Japan); Iwasaki, Kazunari [Department of Environmental Systems Science, Doshisha University, Tatara Miyakodani 1-3, Kyotanabe City, Kyoto 610-0394 (Japan); Kobayashi, Hiroshi; Ishihara, Daisuke; Watanabe, Sakae; Kaneda, Hidehiro [Department of Physics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602 (Japan); Yamamoto, Satoshi, E-mail: aya.higuchi@riken.jp [Department of Physics, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

    2017-04-10

    We have detected [C i] {sup 3} P {sub 1}–{sup 3} P {sub 0} emissions in the gaseous debris disks of 49 Ceti and β Pictoris with the 10 m telescope of the Atacama Submillimeter Telescope Experiment, which is the first detection of such emissions. The line profiles of [C i] are found to resemble those of CO( J = 3–2) observed with the same telescope and the Atacama Large Millimeter/submillimeter Array. This result suggests that atomic carbon (C) coexists with CO in the debris disks and is likely formed by the photodissociation of CO. Assuming an optically thin [C i] emission with the excitation temperature ranging from 30 to 100 K, the column density of C is evaluated to be (2.2 ± 0.2) × 10{sup 17} and (2.5 ± 0.7) × 10{sup 16} cm{sup −2} for 49 Ceti and β Pictoris, respectively. The C/CO column density ratio is thus derived to be 54 ± 19 and 69 ± 42 for 49 Ceti and β Pictoris, respectively. These ratios are higher than those of molecular clouds and diffuse clouds by an order of magnitude. The unusually high ratios of C to CO are likely attributed to a lack of H{sub 2} molecules needed to reproduce CO molecules efficiently from C. This result implies a small number of H{sub 2} molecules in the gas disk, i.e., there is an appreciable contribution of secondary gas from dust grains.

  7. SHARC II: A Caltech Submillimeter Observatory Facility Camera with 384 Pixels

    Science.gov (United States)

    Dowell, C. Darren; Allen, Christine A.; Babu, Sachidananda; Freund, Minoru; Gardner, Matthew B.; Groseth, Jeffrey; Jhabvala, Murzy; Kovacs, Attila; Lis, Dariusz C.; Moseley, S. Harvey, Jr.

    2002-01-01

    SHARC II is a background-limited 350 micron and 450 micron facility camera for the Caltech Submillimeter Observatory undergoing commissioning in 2002. The key component of SHARC II is a 12 x 32 array of doped silicon 'pop-up' bolometers developed at NASA/Goddard. Each 1 mm x 1 mm pixel is coated with a 400 Omega/square bismuth film and located lambda/4 above a reflective backshort to achieve greater than 75% absorption efficiency. The pixels cover the focal plane with greater than 90% filling factor. At 350 microns, the SHARC II pixels are separated by 0.65 lambda/D. In contrast to the silicon bolometers in the predecessor of SHARC II, each doped thermistor occupies nearly the full area of the pixel, which lowers the 1/f knee of tile detector noise to less than 0.03 Hz, under load, at tile bath temperature of 0.36 K. The bolometers are AC-biased and read in 'total power' mode to take advantage of the improved stability. Each bolometer is biased through a custom approx. 130 MOmega CrSi load resistor at 7 K and read with a commercial JFET at 120 K. The JFETs and load resistors are integrated with the detectors into a single assembly to minimize microphonic noise. Electrical connection across the 0.36 K to 4 K and 4 K to 120 K temperature interfaces is accomplished with lithographed metal wires on dielectric substrates. In the best 25% of winter nights on Mauna Kea, SHARC II is expected to have an NEFD at 350 micron of 1 Jy Hz(sup -1/2) or better. The new camera should be at least 4 times faster at detecting known point sources and 30 times faster at mapping large areas compared to the prior instrument.

  8. The rest-frame submillimeter spectrum of high-redshift, dusty, star-forming galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Spilker, J. S.; Marrone, D. P. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Aguirre, J. E. [University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104 (United States); Aravena, M. [European Southern Observatory, Alonso de Cordova 3107, Casilla 19001 Vitacura Santiago (Chile); Ashby, M. L. N. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Béthermin, M. [Laboratoire AIM-Paris-Saclay, CEA/DSM/Irfu-CNRS-Université Paris Diderot, CEA-Saclay, Orme des Merisiers, F-91191 Gif-sur-Yvette (France); Bradford, C. M. [Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Bothwell, M. S. [Cavendish Laboratory, University of Cambridge, JJ Thompson Ave, Cambridge CB3 0HA (United Kingdom); Brodwin, M. [Department of Physics and Astronomy, University of Missouri, 5110 Rockhill Road, Kansas City, MO 64110 (United States); Carlstrom, J. E.; Crawford, T. M. [Kavli Institute for Cosmological Physics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Chapman, S. C. [Dalhousie University, Halifax, Nova Scotia (Canada); De Breuck, C.; Gullberg, B. [European Southern Observatory, Karl Schwarzschild Straße 2, D-85748 Garching (Germany); Fassnacht, C. D. [Department of Physics, University of California, One Shields Avenue, Davis, CA 95616 (United States); Gonzalez, A. H. [Department of Astronomy, University of Florida, Gainesville, FL 32611 (United States); Greve, T. R. [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Hezaveh, Y. [Department of Physics, McGill University, 3600 Rue University, Montreal, Quebec H3A 2T8 (Canada); Holzapfel, W. L., E-mail: jspilker@as.arizona.edu [Department of Physics, University of California, Berkeley, CA 94720 (United States); and others

    2014-04-20

    We present the average rest-frame spectrum of high-redshift dusty, star-forming galaxies from 250 to 770 GHz. This spectrum was constructed by stacking Atacama Large Millimeter/submillimeter Array (ALMA) 3 mm spectra of 22 such sources discovered by the South Pole Telescope and spanning z = 2.0-5.7. In addition to multiple bright spectral features of {sup 12}CO, [C I], and H{sub 2}O, we also detect several faint transitions of {sup 13}CO, HCN, HNC, HCO{sup +}, and CN, and use the observed line strengths to characterize the typical properties of the interstellar medium of these high-redshift starburst galaxies. We find that the {sup 13}CO brightness in these objects is comparable to that of the only other z > 2 star-forming galaxy in which {sup 13}CO has been observed. We show that the emission from the high-critical density molecules HCN, HNC, HCO{sup +}, and CN is consistent with a warm, dense medium with T {sub kin} ∼ 55 K and n{sub H{sub 2}}≳10{sup 5.5} cm{sup –3}. High molecular hydrogen densities are required to reproduce the observed line ratios, and we demonstrate that alternatives to purely collisional excitation are unlikely to be significant for the bulk of these systems. We quantify the average emission from several species with no individually detected transitions, and find emission from the hydride CH and the linear molecule CCH for the first time at high redshift, indicating that these molecules may be powerful probes of interstellar chemistry in high-redshift systems. These observations represent the first constraints on many molecular species with rest-frame transitions from 0.4 to 1.2 mm in star-forming systems at high redshift, and will be invaluable in making effective use of ALMA in full science operations.

  9. High-resolution submillimeter and near-infrared studies of the transition disk around Sz 91

    Energy Technology Data Exchange (ETDEWEB)

    Tsukagoshi, Takashi; Momose, Munetake [College of Science, Ibaraki University, Bunkyo 2-1-1, Mito 310-8512 (Japan); Hashimoto, Jun [Department of Physics and Astronomy, The University of Oklahoma, 440 West Brooks Street, Norman, OK 73019 (United States); Kudo, Tomoyuki; Saito, Masao; Ohashi, Nagayoshi; Kawabe, Ryohei; Akiyama, Eiji [National Astronomical Observatory Japan (NAOJ), Osawa 2-21-1, Mitaka, Tokyo 181-8588 (Japan); Andrews, Sean; Wilner, David [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Kitamura, Yoshimi [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Yoshinodai 3-1-1, Sagamihara, Kanagawa 229-8510 (Japan); Abe, Lyu [Lboratoire Lagrange (UMR 7293), Université de Nice-Sophia Antipolis, CNRS, Observatoire de la Côte d' Azur, 28 avenue Valrose, F-06108 Nice Cedex 2 (France); Brandner, Wolfgang [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); Brandt, Timothy D. [Department of Astrophysical Sciences, Princeton University, Peyton Hall, Ivy Lane, Princeton, NJ 08544 (United States); Carson, Joseph [Department of Physics and Astronomy, College of Charleston, 58 Coming Street, Charleston, SC 29424 (United States); Currie, Thayne [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street M5S 3H4, Toronto, Ontario (Canada); Egner, Sebastian E.; Guyon, Olivier [Subaru Telescope, 650 North A' ohoku Place, Hilo, HI 96720 (United States); Goto, Miwa [Universitäts-Sternwarte München, Ludwig-Maximilians-Universität, Scheinerstr. 1, D-81679 München (Germany); Grady, Carol, E-mail: ttsuka@mx.ibaraki.ac.jp [Exoplanets and Stellar Astrophysics Laboratory, Code 667, Goddard Space Flight Center, Greenbelt, MD 20771 (United States); and others

    2014-03-10

    To reveal the structures of a transition disk around a young stellar object in Lupus, Sz 91 , we have performed aperture synthesis 345 GHz continuum and CO(3-2) observations with the Submillimeter Array (∼1''-3'' resolution) and high-resolution imaging of polarized intensity at the K{sub s} -band using the HiCIAO instrument on the Subaru Telescope (0.''25 resolution). Our observations successfully resolved the inner and outer radii of the dust disk to be 65 and 170 AU, respectively, which indicates that Sz 91 is a transition disk source with one of the largest known inner holes. The model fitting analysis of the spectral energy distribution reveals an H{sub 2} mass of 2.4 × 10{sup –3} M {sub ☉} in the cold (T < 30 K) outer part at 65 AU 3 × 10{sup –9} M {sub ☉}) of hot (T ∼ 180 K) dust possibly remains inside the inner hole of the disk. The structure of the hot component could be interpreted as either an unresolved self-luminous companion body (not directly detected in our observations) or a narrow ring inside the inner hole. Significant CO(3-2) emission with a velocity gradient along the major axis of the dust disk is concentrated on the Sz 91 position, suggesting a rotating gas disk with a radius of 420 AU. The Sz 91 disk is possibly a rare disk in an evolutionary stage immediately after the formation of protoplanets because of the large inner hole and the lower disk mass than other transition disks studied thus far.

  10. Submillimeter Imaging of Dust Around Main Sequence Stars

    Science.gov (United States)

    Jewitt, David

    1998-01-01

    This grant was to image circumstellar dust disks surrounding main-sequence stars. The delivery of the SCUBA detector we had planned to use for this work was delayed repeatedly, leading us to undertake a majority of the observations with the UKT14 submillimeter detector at the JCMT (James Clerk Maxwell Telescope) and optical imagers and a coronagraph at the University of Hawaii 2.2-m telescope. Major findings under this grant include: (1) We discovered 5 asymmetries in the beta Pictoris regenerated dust disk. The discovery of these asymmetries was a surprise, since smearing due to Keplerian shear should eliminate most such features on timescales of a few thousand years. One exception is the "wing tilt" asymmetry, which we interpret as due to the scattering phase function of dust disk particles. From the wing tilt and a model of the phase function, we find a disk plane inclination to the line of sight of JCMT). It is possible, for instance, that the main 850 micro-m blob is merely a galaxy or other high-z source projected onto the beta Pic mid-plane.

  11. Extending the Millimeter-Submillimeter Spectrum of Protonated Formaldehyde

    Science.gov (United States)

    Roenitz, Kevin; Zou, Luyao; Widicus Weaver, Susanna L.

    2017-06-01

    Protonated formaldehyde has been detected in the interstellar medium, where it participates in the formation and destruction of methanol. The rotational spectrum for protonated formaldehyde has been previously recorded by Amano and coworkers from 120-385 GHz using a hollow cathode discharge source for ion production. Additionally, protonated formaldehyde was produced in a supersonic expansion discharge source by Duncan and coworkers, but it was detected using time-of-flight mass spectrometry. Higher frequency spectra would help to guide additional observational studies of protonated formaldehyde using instruments such as the ALMA and SOFIA observatories. As such, we have used a supersonic expansion discharge source to produce protonated formaldehyde, and recorded its spectrum using millimeter-submillimeter direct absorption spectroscopy. The rotational spectrum was recorded from 350-1000 GHz. Here we will present the experimental design, specifically focusing on the optimization of the source for production of organic ions. We will also present the spectroscopic results for protonated formaldehyde and a spectral analysis with associated prediction that can be extended to frequencies above 1 THz.

  12. Faint submillimeter galaxies revealed by multifield deep ALMA observations: number counts, spatial clustering, and a dark submillimeter line emitter

    Energy Technology Data Exchange (ETDEWEB)

    Ono, Yoshiaki; Ouchi, Masami; Momose, Rieko [Institute for Cosmic Ray Research, The University of Tokyo, Kashiwa, Chiba 277-8582 (Japan); Kurono, Yasutaka, E-mail: ono@icrr.u-tokyo.ac.jp [Joint ALMA Observatory, Alonso de Cordova 3107, Vitacura, Santiago 763-0355 (Chile)

    2014-11-01

    We present the statistics of faint submillimeter/millimeter galaxies (SMGs) and serendipitous detections of a submillimeter/millimeter line emitter (SLE) with no multi-wavelength continuum counterpart revealed by the deep ALMA observations. We identify faint SMGs with flux densities of 0.1-1.0 mJy in the deep Band-6 and Band-7 maps of 10 independent fields that reduce cosmic variance effects. The differential number counts at 1.2 mm are found to increase with decreasing flux density down to 0.1 mJy. Our number counts indicate that the faint (0.1-1.0 mJy, or SFR{sub IR} ∼ 30-300 M {sub ☉} yr{sup –1}) SMGs contribute nearly a half of the extragalactic background light (EBL), while the remaining half of the EBL is mostly contributed by very faint sources with flux densities of <0.1 mJy (SFR{sub IR} ≲ 30 M {sub ☉} yr{sup –1}). We conduct counts-in-cells analysis with multifield ALMA data for the faint SMGs, and obtain a coarse estimate of galaxy bias, b {sub g} < 4. The galaxy bias suggests that the dark halo masses of the faint SMGs are ≲ 7 × 10{sup 12} M {sub ☉}, which is smaller than those of bright (>1 mJy) SMGs, but consistent with abundant high-z star-forming populations, such as sBzKs, LBGs, and LAEs. Finally, we report the serendipitous detection of SLE-1, which has no continuum counterparts in our 1.2 mm-band or multi-wavelength images, including ultra deep HST/WFC3 and Spitzer data. The SLE has a significant line at 249.9 GHz with a signal-to-noise ratio of 7.1. If the SLE is not a spurious source made by the unknown systematic noise of ALMA, the strong upper limits of our multi-wavelength data suggest that the SLE would be a faint galaxy at z ≳ 6.

  13. Voltage tunable differential heterodyne spectroscopy in the far-infrared with Josephson junctions

    Science.gov (United States)

    Ulrich, B. T.

    1978-01-01

    The basic methods of differential heterodyne spectroscopy with Josephson junctions are described. A technique is outlined for bridging the gap between a local oscillator frequency and a signal frequency through the use of a voltage-tunable internal oscillation frequency in a Josephson junction structure. It is shown that an intermediate frequency can be converted to a conveniently low frequency by double frequency conversion carried out directly in a Josephson junction. The expected conversion efficiency is estimated qualitatively. Experiments are discussed in which the differential heterodyne frequency-conversion technique was demonstrated at a wavelength of 0.4 mm and a voltage-tunable oscillation in a double Josephson junction structure was observed, with oscillation line widths as narrow as 0.5 Hz, for a resistance of 3.3 nanohms and an estimated inductance of the order of 1 nH.

  14. A Miniaturized Laser Heterodyne Radiometer for Greenhouse Gas Measurements in the Atmospheric Column

    Science.gov (United States)

    Steel, Emily Wilson

    2015-01-01

    Laser Heterodyne Radiometry is a technique adapted from radio receiver technology has been used to measure trace gases in the atmosphere since the 1960s.By leveraging advances in the telecommunications industry, it has been possible to miniaturize this technology.The mini-LHR (Miniaturized Laser Heterodyne Radiometer) has been under development at NASA Goddard Space flight Center since 2009. This sun-viewing instrument measures carbon dioxide and methane in the atmospheric column and operates in tandem with an AERONET sun photometer producing a simultaneous measure of aerosols. The mini-LHR has been extensively field tested in a range of locations ranging in the continental US as well as Alaska and Hawaii and now operates autonomously with sensitivities of approximately 0.2 ppmv and approximately10 ppbv, for carbon dioxide and methane respectively, for 10 averaged scans under clear sky conditions.

  15. Experimental study on the 1550 nm all fiber heterodyne laser range finder.

    Science.gov (United States)

    Yang, Fu; He, Yan; Shang, Jianhua; Chen, Weibiao

    2009-12-01

    In this paper, a 1550 nm all fiber monostatic laser range finder system based on linear chirp modulation and heterodyne detection is presented. The fiber end face signal is used as a range starting indicator. The transmitted laser power is 5 mW with a laser pulse length of 131 micros and a linear chirp bandwidth of 40 MHz. The telescope with an aperture of 3 cm couples the return light into a single mode fiber. Better than 14 cm distance accuracy and 26 dB SNR can be achieved for a wood target at a distance of about 43 m by using the above system setup. Several experiments with different system parameters are conducted. The system performance is tested under variable laser pulse length, linear chirp bandwidth, local oscillator power, and background noise. Finally, an application of the linear chirp modulation heterodyne laser range finder in a spaceborne ranging system is proposed.

  16. Heterodyne lock-in thermography of early demineralized in dental tissues

    Science.gov (United States)

    Wang, Fei; Liu, Jun-yan; Mohummad, Oliullah; Wang, Xiao-chun; Wang, Yang

    2017-12-01

    Heterodyne lock-in thermography (HeLIT) is a highly sensitive method to detect early demineralized in dental tissues, which is based on nonlinear photothermal phenomena of dental tissues. In this paper, the nonlinear photothermal phenomena of dental tissues was introduced, and then the system of HeLIT was developed. The relationship between laser modulated parameters (modulated frequency and laser intensity) and heterodyne lock-in thermal wave signal was investigated. The comparison between HeLIT and homodyne lock-in thermography (HoLIT) for detecting the different types of dental caries (smooth surface caries, proximal surface caries and occlusal surface caries) were carried out. Experimental results illustrate that the HeLIT has the merits of high sensitivity and high specificity in detecting different types of early caries.

  17. Laser-diode interferometric heterodyne vibrometer: application to linear motor control.

    Science.gov (United States)

    Chebbour, A; Gharbi, T; Tribillon, G

    2001-11-01

    We describe an interferometric heterodyne vibrometer that uses a laser diode with a triangular modulation frequency. This optical sensor is used to probe a vibrating polished surface. As an illustration of the sensor performance, the control of nonuniform velocity of a linear motor is achieved. The technique can be used over a large bandwidth between a few hertz and several tens of kilohertz. Generalization of the technique to the sensing of frequency vibrations is also demonstrated theoretically.

  18. Study of optical nonlinearity of a highly dispersive medium using optical heterodyne detection technique

    CERN Document Server

    Bhowmick, Arup; Mohapatra, Ashok K

    2016-01-01

    We discuss the optical heterodyne detection technique to study the absorption and dispersion of a probe beam propagating through a medium with a narrow resonance. The technique has been demonstrated for Rydberg Electro-magnetically induced transparency (EIT) in rubidium thermal vapor and the optical non-linearity of a probe beam with variable intensity has been studied. A quantitative comparison of the experimental result with a suitable theoretical model is presented. The limitations and the working regime of the technique are discussed.

  19. Design of a full-dynamic-range balanced detection heterodyne gyroscope with common-path configuration.

    Science.gov (United States)

    Lin, Chu-En; Yu, Chih-Jen; Chen, Chii-Chang

    2013-04-22

    In this article, we propose an optical heterodyne common-path gyroscope which has common-path configuration and full-dynamic range. Different from traditional non-common-path optical heterodyne technique such as Mach-Zehnder or Michelson interferometers, we use a two-frequency laser light source (TFLS) which can generate two orthogonally polarized light with a beat frequency has a common-path configuration. By use of phase measurement, this optical heterodyne gyroscope not only has the capability to overcome the drawback of the traditional interferometric fiber optic gyro: lack for full-dynamic range, but also eliminate the total polarization rotation caused by SMFs. Moreover, we also demonstrate the potential of miniaturizing this gyroscope as a chip device. Theoretically, if we assume that the wavelength of the laser light is 1550nm, the SMFs are 250m in length, and the radius of the fiber ring is 3.5cm, the bias stability is 0.872 deg/hr.

  20. Improved synthetic-heterodyne Michelson interferometer vibrometer using phase and gain control feedback.

    Science.gov (United States)

    Galeti, José Henrique; Kitano, Cláudio; Connelly, Michael J

    2015-12-10

    Synthetic-heterodyne demodulation is a useful technique for dynamic displacement and velocity measurement using interferometric sensors as it can provide an output signal which is immune to interferometric drift. With the advent of cost effective, high-speed real-time signal processing systems and software, processing of the complex signals encountered in interferometry has become more feasible. In conventional synthetic-heterodyne demodulation schemes, to obtain the dynamic displacement or vibration of the object under test requires knowledge of the interferometer visibility and also the argument of two Bessel functions. In this paper, a new synthetic-heterodyne demodulation method is described leading to an expression for the dynamic displacement and velocity of the object under test that is significantly less sensitive to the received optical power. In addition, the application of two independent phase and gain feedback loops is used to compensate for the nonideal gain and phase response of the anti-aliasing filter required for the signal acquisition of the received wideband interferometer signal. The efficacy of the improved system is demonstrated by measuring the displacement sensitivity frequency response and linearity of a Piezoelectric Mirror-Shifter (PMS) over a range of 200 Hz-9 kHz. In addition, the system is used to measure the response of the PMS to triangular and impulse type stimuli. The experimental results show excellent agreement with measurements taken using two independent industry standard calibration methods.

  1. Common mode noise rejection properties of amplitude and phase noise in a heterodyne interferometer.

    Science.gov (United States)

    Hechenblaikner, Gerald

    2013-05-01

    High precision metrology systems based on heterodyne interferometry can measure the position and attitude of objects to accuracies of picometer and nanorad, respectively. A frequently found feature of the general system design is the subtraction of a reference phase from the phase of the position interferometer, which suppresses low frequency common mode amplitude and phase fluctuations occurring in volatile optical path sections shared by both the position and reference interferometer. Spectral components of the noise at frequencies around or higher than the heterodyne frequency, however, are generally transmitted into the measurement band and may limit the measurement accuracy. Detailed analytical calculations complemented with Monte Carlo simulations show that high frequency noise components may also be entirely suppressed, depending on the relative difference of measurement and reference phase, which may be exploited by corresponding design provisions. While these results are applicable to any heterodyne interferometer with certain design characteristics, specific calculations and related discussions are given for the example of the optical metrology system of the LISA Pathfinder mission to space.

  2. Measuring ultra-sonic in-plane vibrations with the scanning confocal heterodyne interferometer

    Science.gov (United States)

    Rembe, C.; Ur-Rehman, F.; Heimes, F.; Boedecker, S.; Dräbenstedt, A.

    2010-05-01

    The advanced progress in miniaturization technologies of mechanical systems and structures has led to a growing demand of measurement tools for three-dimensional vibrations at ultra-high frequencies. Particularly radio-frequency, micro-electro-mechanical (RF-MEM) technology is a planar technology and, thus, the resonating structures are much larger in lateral dimensions compared to the height. Consequently, most ultra-high-frequency devices have larger inplane vibration amplitudes than out-of-plane amplitudes. Recently, we have presented a heterodyne interferometer for vibration frequencies up to 1.2 GHz. In this paper we demonstrate a new method to extract broad-bandwidth spectra of in-plane vibrations with our new heterodyne interferometer. To accomplish this goal we have combined heterodyne interferometry, scanning vibrometry, edge-knife technique, amplitude demodulation, and digital-image processing. With our experimental setup we can realize in-plane vibration measurements up to 600 MHz. We will also show our first measurements of a broad-bandwidth, in-plane vibration around 200 MHz. Our in-plane and out-of-plane vibration measurements are phase-correlated and, therefore, our technique is suitable for broad-bandwidth, full-3D vibration measurements of ultrasonic microdevices.

  3. Compact Setup of a Tunable Heterodyne Spectrometer for Infrared Observations of Atmospheric Trace-Gases

    Directory of Open Access Journals (Sweden)

    Manuela Sornig

    2013-07-01

    Full Text Available We report on the development and characterization of the new  compact infrared heterodyne receiver, iChips (Infrared Compact Heterodyne Instrument for Planetary Science. It is specially designed for ground-based observations of the terrestrial atmosphere in the mid-infrared wavelength region. Mid-infrared room temperature quantum cascade lasers are implemented into a heterodyne system for the first time. Their tunability allows the instrument to operate in two different modes.  The scanning mode covers a spectral range of few wavenumbers continuously with a resolution of approximately ν/∆ν ≥ 105. This mode allows the determination of the terrestrial atmospheric transmission. The staring mode, applied for observations of single molecular transition features, provides a spectral resolution of ν/∆ν ≥ 107 and a bandwidth of 1.4  GHz.  To demonstrate the instrument's capabilities, initial observations in both modes were performed by measuring the terrestrial transmittance at 7.8 µm (∼ 1,285 cm−1 and by probing terrestrial ozone features at 8.6 µm (∼ 1,160 cm−1, respectively. The receivers characteristics and performance are described.

  4. Development of a fast sweep heterodyne microwave reflectometer; Developpement d`un reflectometre micro-onde heterodyne a balayage ultra rapide

    Energy Technology Data Exchange (ETDEWEB)

    Moreau, Ph. [Association Euratom-CEA, Centre d`Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee]|[Universite de Provence, 13 - Marseille (France)

    1997-12-01

    The density profile of fusion plasmas can be investigated by the reflectometry diagnostic. The measurement principle is based on the radar techniques which calculate the phase shift of a millimeter wave propagating into the plasma and reflected at a cut-off layer. We have tried to describe the density fluctuation effects upon detected signal to understand the disturbing mechanisms which prevent, sometime, the measurement of the phase. First, we have tried to understand the mechanisms and the origin of the turbulence which is responsible for phase disturbance. We point out the role of collisionality {nu}{sup *} and plasma radiation (with the Hugill normalised parameter H) which control the instability. We also demonstrate that the phase delay of the probing wave is very sensitive to the plasma MHD phenomena and is less affected by the micro-turbulence. The second part of this work is the development and the use of a new heterodyne reflectometer. This new diagnostic uses O-mode beam polarisation and works on the 26-36 GHz frequency range. It launches simultaneously into the plasma two frequencies separated by 320 MHz and we can study them separately or with the amplitude modulation technique. It possesses a better sensitivity than the previous homodyne reflectometer and a higher frequency agility. Its heterodyne detection allows us to separate phase and amplitude informations from the detected signal. (author) 93 refs.

  5. Advanced Technologies For Heterodyne Radio Astronomy Instrumentation - Part1 By A. Pavolotsky, And Advanced Technologies For Heterodyne Radio Astronomy Instrumentation - Part2 By V. Desmaris

    Science.gov (United States)

    Pavolotsky, Alexey

    2018-01-01

    Modern and future heterodyne radio astronomy instrumentation critically depends on availability of advanced fabrication technologies and components. In Part1 of the Poster, we present the thin film fabrication process for SIS mixer receivers, utilizing either AlOx, or AlN barrier superconducting tunnel junctions developed and supported by GARD. The summary of the process design rules is presented. It is well known that performance of waveguide mixer components critically depends on accuracy of their geometrical dimensions. At GARD, all critical mechanical parts are 3D-mapped with a sub-um accuracy. Further progress of heterodyne instrumentation requires new efficient and compact sources of LO signal. We present SIS-based frequency multiplier, which could become a new option for LO source. Future radio astronomy THz receivers will need waveguide components, which fabricating due to their tiny dimensions is not feasible by traditional mechanical machining. We present the alternative micromachining technique for fabricating waveguide component for up 5 THz band and probably beyond.

  6. Detection of Enceladus Torus from Submillimeter Observations with Herschel/HIFI

    NARCIS (Netherlands)

    Lellouch, Emmanuel; Hartogh, P.; Moreno, R.; Bockelée-Morvan, D.; Biver, N.; Jarchow, C.; Rengel, M.; Cavalié, T.; Helmich, F.; HssO Team, [Unknown

    2010-01-01

    The presence of water vapor in the stratospheres of the Giant Planets and Titan has been established from their emission in rotational lines longwards of 30 microns. Emission in the fundamental H2O line at 557 GHz has been spectrally resolved from heterodyne observations with SWAS at Jupiter and

  7. Formation of Combined Surface Features of Protrusion Array and Wrinkles atop Shape-Memory Polymer

    Science.gov (United States)

    Sun, L.; Zhao, Y.; Huang, W. M.; Tong, T. H.

    We demonstrate a simple and cost-effective approach to realize two combined surface features of different scales together, namely submillimeter-sized protrusion array and microwrinkles, atop a polystyrene shape-memory polymer. Two different types of protrusions, namely flat-top protrusion and crown-shaped protrusion, were studied. The array of protrusions was produced by the Indentation-Polishing-Heating (IPH) process. Compactly packed steel balls were used for making array of indents. A thin gold layer was sputter deposited atop the polymer surface right after polishing. After heating for shape recovery, array of protrusions with wrinkles on the top due to the buckling of gold layer was produced.

  8. Submillimeter Galaxies as Progenitors of Compact Quiescent Galaxies

    Science.gov (United States)

    Toft, S.; Smolcic, V.; Magnelli, B.; Karim, A.; Zirm, A.; Michalowski, M.; Capak, P.; Sheth, K.; Schawinski, K.; Krogager, J.-K.; hide

    2014-01-01

    Three billion years after the big bang (at redshift z = 2), half of the most massive galaxies were already old, quiescent systems with little to no residual star formation and extremely compact with stellar mass densities at least an order of magnitude larger than in low-redshift ellipticals, their descendants. Little is known about how they formed, but their evolved, dense stellar populations suggest formation within intense, compact starbursts 1-2 Gyr earlier (at 3 < z < 6). Simulations show that gas-rich major mergers can give rise to such starbursts, which produce dense remnants. Submillimeter-selected galaxies (SMGs) are prime examples of intense, gas-rich starbursts.With a new, representative spectroscopic sample of compact, quiescent galaxies at z = 2 and a statistically well-understood sample of SMGs, we show that z = 3-6 SMGs are consistent with being the progenitors of z = 2 quiescent galaxies, matching their formation redshifts and their distributions of sizes, stellar masses, and internal velocities. Assuming an evolutionary connection, their space densities also match if the mean duty cycle of SMG starbursts is 42(sup+40) -29 Myr (consistent with independent estimates), which indicates that the bulk of stars in these massive galaxies were formed in a major, early surge of star formation. These results suggest a coherent picture of the formation history of the most massive galaxies in the universe, from their initial burst of violent star formation through their appearance as high stellar-density galaxy cores and to their ultimate fate as giant ellipticals.

  9. Submillimeter galaxies as progenitors of compact quiescent galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Toft, S.; Zirm, A.; Krogager, J.-K.; Man, A. W. S. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Mariesvej 30, DK-2100 Copenhagen (Denmark); Smolčić, V.; Krpan, J. [Physics Department, University of Zagreb, Bijenička cesta 32, 10002 Zagreb (Croatia); Magnelli, B.; Karim, A. [Argelander Institute for Astronomy, Auf dem Hügel 71, Bonn, D-53121 (Germany); Michalowski, M. [Scottish Universities Physics Alliance, Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh, EH9 3HJ (United Kingdom); Capak, P. [Spitzer Science Center, 314-6 Caltech, 1201 East California Boulevard, Pasadena, CA 91125 (United States); Sheth, K. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Schawinski, K. [ETH Zurich, Institute for Astronomy, Department of Physics, Wolfgang-Pauli-Strasse 27, CH-8093 Zurich (Switzerland); Wuyts, S.; Lutz, D.; Staguhn, J.; Berta, S. [MPE, Postfach 1312, D-85741 Garching (Germany); Sanders, D. [Institute for Astronomy, 2680 Woodlawn Drive, University of Hawaii, Honolulu, HI 96822 (United States); Mccracken, H. [Institut dAstrophysique de Paris, UMR7095 CNRS, Universite Pierre et Marie Curie, 98 bis Boulevard Arago, F-75014 Paris (France); Riechers, D., E-mail: sune@dark-cosmology.dk [Department of Astronomy, Cornell University, 220 Space Sciences Building, Ithaca, NY 14853 (United States)

    2014-02-20

    Three billion years after the big bang (at redshift z = 2), half of the most massive galaxies were already old, quiescent systems with little to no residual star formation and extremely compact with stellar mass densities at least an order of magnitude larger than in low-redshift ellipticals, their descendants. Little is known about how they formed, but their evolved, dense stellar populations suggest formation within intense, compact starbursts 1-2 Gyr earlier (at 3 < z < 6). Simulations show that gas-rich major mergers can give rise to such starbursts, which produce dense remnants. Submillimeter-selected galaxies (SMGs) are prime examples of intense, gas-rich starbursts. With a new, representative spectroscopic sample of compact, quiescent galaxies at z = 2 and a statistically well-understood sample of SMGs, we show that z = 3-6 SMGs are consistent with being the progenitors of z = 2 quiescent galaxies, matching their formation redshifts and their distributions of sizes, stellar masses, and internal velocities. Assuming an evolutionary connection, their space densities also match if the mean duty cycle of SMG starbursts is 42{sub −29}{sup +40} Myr (consistent with independent estimates), which indicates that the bulk of stars in these massive galaxies were formed in a major, early surge of star formation. These results suggest a coherent picture of the formation history of the most massive galaxies in the universe, from their initial burst of violent star formation through their appearance as high stellar-density galaxy cores and to their ultimate fate as giant ellipticals.

  10. Long-term stabilization of a heterodyne metrology interferometer down to a noise level of 20 pm over an hour

    Energy Technology Data Exchange (ETDEWEB)

    Niwa, Yoshito; Arai, Koji; Ueda, Akitoshi; Sakagami, Masaaki; Gouda, Naoteru; Kobayashi, Yukiyasu; Yamada, Yoshiyuki; Yano, Taihei

    2009-11-10

    A heterodyne metrology interferometer was stabilized down to a noise level of 20 picometers (pm) as a root-mean-square (RMS) value integrated between 0.3 mHz and 1 Hz. This noise level was achieved by employing active and passive interferometer stabilization techniques. The heterodyne interferometer was built on a 50 mm square ultralow expansion glass plate in order to reduce an optical path length change caused by temperature variation. An optical configuration of the interferometer is a Mach-Zehnder interferometer with a design as symmetric as possible so that a detection signal can be insensitive to homogeneous thermal expansion of the glass plate. The heterodyne frequency is actively controlled in order to suppress residual noises caused by optical path length changes outside of the glass plate as well as phase fluctuations of the heterodyne frequency source. Our stabilization scheme is considered useful in achieving the 20 pm noise level without a stable heterodyne frequency source, as well as temperature stabilization around a whole apparatus. This interferometer can be used in precise metrology applications, such as characterization of deformation for satellite optical components against thermal exposure.

  11. Long-term stabilization of a heterodyne metrology interferometer down to a noise level of 20 pm over an hour.

    Science.gov (United States)

    Niwa, Yoshito; Arai, Koji; Ueda, Akitoshi; Sakagami, Masaaki; Gouda, Naoteru; Kobayashi, Yukiyasu; Yamada, Yoshiyuki; Yano, Taihei

    2009-11-10

    A heterodyne metrology interferometer was stabilized down to a noise level of 20 picometers (pm) as a root-mean-square (RMS) value integrated between 0.3 mHz and 1 Hz. This noise level was achieved by employing active and passive interferometer stabilization techniques. The heterodyne interferometer was built on a 50 mm square ultralow expansion glass plate in order to reduce an optical path length change caused by temperature variation. An optical configuration of the interferometer is a Mach-Zehnder interferometer with a design as symmetric as possible so that a detection signal can be insensitive to homogeneous thermal expansion of the glass plate. The heterodyne frequency is actively controlled in order to suppress residual noises caused by optical path length changes outside of the glass plate as well as phase fluctuations of the heterodyne frequency source. Our stabilization scheme is considered useful in achieving the 20 pm noise level without a stable heterodyne frequency source, as well as temperature stabilization around a whole apparatus. This interferometer can be used in precise metrology applications, such as characterization of deformation for satellite optical components against thermal exposure.

  12. Mu-Spec: A High Performance Compact Spectrometer for Submillimeter Astronomy

    Science.gov (United States)

    Hsieh, Wen-Ting; Moseley, Harvey; Stevenson, Thomas; Brown, Ari; Patel, Amil; U-yen, Kongpop; Ehsan, Negar; Cataldo, Giuseppe; Wollack, Ed

    2012-01-01

    We describe the Mu-Spec, an extremely compact high performance spectrometer for the submillimeter and millimeter spectral ranges. We have designed a fully integrated submillimeter spectrometer based on superconducting microstrip technology and fabricated its critical elements. Using low loss transmission lines, we can produce a fully integrated high resolution submillimeter spectrometer on a single four inch Si wafer. A resolution of 500 can readily be achieved with standard fabrication tolerance, higher with phase trimming. All functions of the spectrometer are integrated - light is coupled to the microstrip circuit with a planar antenna, the spectra discrimination is achieved using a synthetic grating, orders are separated using a built-in planar filter, and the light is detected using photon counting Microwave Kinetic Inductance Detectors (MKID). We will discus the design principle of the instrument, describe its technical advantages, and report the progress on the development of the instrument.

  13. Micro-Spec: A High Performance Compact Spectrometer for Submillimeter Astronomy

    Science.gov (United States)

    Hsieh, Wen-Ting; Moseley, Harvey; Stevenson, Thomas; Brown, Ari; Patel, Amil; U-Yen, Kongpop; Ehsan, Negar; Caltado, Giuseppe; Wollock, Edward

    2012-01-01

    We describe the micro-Spec, an extremely compact high performance spectrometer for the submillimeter and millimeter spectral ranges. We have designed a fully integrated submillimeter spectrometer based on superconducting microstrip technology and fabricated its critical elements. Using low loss transmission lines, we can produce a fully integrated high resolution submillimeter spectrometer on a single four inch Si wafer. A resolution of 500 can readily be achieved with standard fabrication tolerance, higher with phase trimming. All functions of the spectrometer are integrated - light is coupled to the micro strip circuit with a planar antenna, the spectra discrimination is achieved using a synthetic grating, orders are separated using a built-in planar filter, and the light is detected using photon counting Microwave Kinetic Inductance Detectors (MKID). We will discus the design principle of the instrument, describe its technical advantages, and report the progress on the development of the instrument.

  14. Ionoacoustic characterization of the proton Bragg peak with submillimeter accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Assmann, W., E-mail: walter.assmann@lmu.de; Reinhardt, S.; Lehrack, S.; Edlich, A.; Thirolf, P. G.; Parodi, K. [Department for Medical Physics, Ludwig-Maximilians-Universität München, Am Coulombwall 1, Garching 85748 (Germany); Kellnberger, S.; Omar, M.; Ntziachristos, V. [Institute for Biological and Medical Imaging, Technische Universität München and Helmholtz Zentrum München, Ingolstädter Landstrasse 1, Neuherberg 85764 (Germany); Moser, M.; Dollinger, G. [Institute for Applied Physics and Measurement Technology, Universität der Bundeswehr, Werner-Heisenberg-Weg 39, Neubiberg 85577 (Germany)

    2015-02-15

    Purpose: Range verification in ion beam therapy relies to date on nuclear imaging techniques which require complex and costly detector systems. A different approach is the detection of thermoacoustic signals that are generated due to localized energy loss of ion beams in tissue (ionoacoustics). Aim of this work was to study experimentally the achievable position resolution of ionoacoustics under idealized conditions using high frequency ultrasonic transducers and a specifically selected probing beam. Methods: A water phantom was irradiated by a pulsed 20 MeV proton beam with varying pulse intensity and length. The acoustic signal of single proton pulses was measured by different PZT-based ultrasound detectors (3.5 and 10 MHz central frequencies). The proton dose distribution in water was calculated by Geant4 and used as input for simulation of the generated acoustic wave by the matlab toolbox k-WAVE. Results: In measurements from this study, a clear signal of the Bragg peak was observed for an energy deposition as low as 10{sup 12} eV. The signal amplitude showed a linear increase with particle number per pulse and thus, dose. Bragg peak position measurements were reproducible within ±30 μm and agreed with Geant4 simulations to better than 100 μm. The ionoacoustic signal pattern allowed for a detailed analysis of the Bragg peak and could be well reproduced by k-WAVE simulations. Conclusions: The authors have studied the ionoacoustic signal of the Bragg peak in experiments using a 20 MeV proton beam with its correspondingly localized energy deposition, demonstrating submillimeter position resolution and providing a deep insight in the correlation between the acoustic signal and Bragg peak shape. These results, together with earlier experiments and new simulations (including the results in this study) at higher energies, suggest ionoacoustics as a technique for range verification in particle therapy at locations, where the tumor can be localized by ultrasound

  15. The SCUBA-2 Cosmology Legacy Survey: Multi-wavelength Properties of ALMA-identified Submillimeter Galaxies in UKIDSS UDS

    NARCIS (Netherlands)

    Simpson, J. M.; Smail, Ian; Swinbank, A. M.; Ivison, R. J.; Dunlop, J. S.; Geach, J. E.; Almaini, O.; Arumugam, V.; Bremer, M. N.; Chen, Chian-Chou; Conselice, C.; Coppin, K. E. K.; Farrah, D.; Ibar, E.; Hartley, W. G.; Ma, C. J.; Michałowski, M. J.; Scott, D.; Spaans, M.; Thomson, A. P.; van der Werf, P. P.

    2017-01-01

    We present a multi-wavelength analysis of 52 submillimeter galaxies (SMGs), identified using ALMA 870 μm continuum imaging in a pilot program to precisely locate bright SCUBA-2-selected submillimeter sources in the UKIDSS Ultra Deep Survey (UDS) field. Using the available deep (especially

  16. Internal rupture and rapid bouncing of impacting drops induced by submillimeter-scale textures

    Science.gov (United States)

    Zhang, Rui; Zhang, Xiwen; Hao, Pengfei; He, Feng

    2017-06-01

    We demonstrate an internal breakup mechanism for high Weber number drop impact on superhydrophobic surfaces uniformly patterned with submillimeter-scale textures, in which the liquid film ruptures from both interior and rim. The employment of submillimeter-scale posts could help decrease the critical Weber number of internal rupture, due to the small solid fraction and the large dimension ratio between primary structures and droplets. The internal rupture is found to promote more rapid drop bouncing than conventional rebound and rim breakup on superhydrophobic surfaces with small roughness, with a 10%-50% reduction of contact time. The internal rupture results from the film instability inside and the jet instability outside.

  17. Internal rupture and rapid bouncing of impacting drops induced by submillimeter-scale textures.

    Science.gov (United States)

    Zhang, Rui; Zhang, Xiwen; Hao, Pengfei; He, Feng

    2017-06-01

    We demonstrate an internal breakup mechanism for high Weber number drop impact on superhydrophobic surfaces uniformly patterned with submillimeter-scale textures, in which the liquid film ruptures from both interior and rim. The employment of submillimeter-scale posts could help decrease the critical Weber number of internal rupture, due to the small solid fraction and the large dimension ratio between primary structures and droplets. The internal rupture is found to promote more rapid drop bouncing than conventional rebound and rim breakup on superhydrophobic surfaces with small roughness, with a 10%-50% reduction of contact time. The internal rupture results from the film instability inside and the jet instability outside.

  18. An alma survey of sub-millimeter galaxies in the extended Chandra deep field south: Sub-millimeter properties of color-selected galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Decarli, R.; Walter, F.; Hodge, J. A.; Rix, H.-W.; Schinnerer, E. [Max-Planck Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany); Smail, I.; Swinbank, A. M.; Karim, A.; Simpson, J. M. [Institute for Computational Cosmology, Durham University, South Road, Durham DH1 3LE (United Kingdom); Chapman, S. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Coppin, K. E. K. [Centre for Astrophysics, Science and Technology Research Institute, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom); Cox, P. [IRAM, 300 rue de la piscine, F-38406 Saint-Martin d' Hères (France); Dannerbauer, H. [Universität Wien, Institut für Astrophysik, Türenschanzstrasse 17, A-1180 Wien (Austria); Greve, T. R. [University College London, Department of Physics and Astronomy, Gower Street, London WC1E 6BT (United Kingdom); Ivison, R. [Institute for Astronomy, University of Edinburgh, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Knudsen, K. K.; Lindroos, L. [Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, Onsala SE-439 92 (Sweden); Van der Werf, P. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Weiß, A., E-mail: decarli@mpia.de [Max-Planck Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany)

    2014-01-10

    We study the sub-millimeter properties of color-selected galaxies via a stacking analysis applied for the first time to interferometric data at sub-millimeter wavelengths. We base our study on 344 GHz ALMA continuum observations of ∼20''-wide fields centered on 86 sub-millimeter sources detected in the LABOCA Extended Chandra Deep Field South (ECDFS) Sub-millimeter Survey. We select various classes of galaxies (K-selected, star-forming sBzK galaxies, extremely red objects, and distant red galaxies) according to their optical/near-infrared fluxes. We find clear, >10σ detections in the stacked images of all these galaxy classes. We include in our stacking analysis Herschel/SPIRE data to constrain the dust spectral energy distribution of these galaxies. We find that their dust emission is well described by a modified blackbody with T {sub dust} ≈ 30 K and β = 1.6 and infrared luminosities of (5-11) × 10{sup 11} L {sub ☉} or implied star formation rates of 75-140 M {sub ☉} yr{sup –1}. We compare our results with those of previous studies based on single-dish observations at 870 μm and find that our flux densities are a factor 2-3 higher than previous estimates. The discrepancy is observed also after removing sources individually detected in ALESS maps. We report a similar discrepancy by repeating our analysis on 1.4 GHz observations of the whole ECDFS. Hence, we find tentative evidence that galaxies that are associated in projected and redshift space with sub-mm bright sources are brighter than the average population. Finally, we put our findings in the context of the cosmic star formation rate density as a function of redshift.

  19. Michelson interferometer vibrometer using self-correcting synthetic-heterodyne demodulation.

    Science.gov (United States)

    Connelly, Michael J; Galeti, José Henrique; Kitano, Cláudio

    2015-06-20

    Synthetic-heterodyne demodulation is a useful technique for dynamic displacement and velocity detection in interferometric sensors, as it can provide an output signal that is immune to interferometric drift. With the advent of cost-effective, high-speed real-time signal-processing systems and software, processing of the complex signals encountered in interferometry has become more feasible. In synthetic heterodyne, to obtain the actual dynamic displacement or vibration of the object under test requires knowledge of the interferometer visibility and also the argument of two Bessel functions. In this paper, a method is described for determining the former and setting the Bessel function argument to a set value, which ensures maximum sensitivity. Conventional synthetic-heterodyne demodulation requires the use of two in-phase local oscillators; however, the relative phase of these oscillators relative to the interferometric signal is unknown. It is shown that, by using two additional quadrature local oscillators, a demodulated signal can be obtained that is independent of this phase difference. The experimental interferometer is a Michelson configuration using a visible single-mode laser, whose current is sinusoidally modulated at a frequency of 20 kHz. The detected interferometer output is acquired using a 250 kHz analog-to-digital converter and processed in real time. The system is used to measure the displacement sensitivity frequency response and linearity of a piezoelectric mirror shifter over a range of 500 Hz to 10 kHz. The experimental results show good agreement with two data-obtained independent techniques: the signal coincidence and denominated n-commuted Pernick method.

  20. Ground Based Observation of Isotopic Oxygen in the Martian Atmosphere Using Infrared Heterodyne Spectroscopy

    Science.gov (United States)

    Smith, R. L.; Kostiuk, T.; Livengood, T. A.; Fast, K. E.; Hewagama, T.; Delgado, J. D.; Sonnabend, G.

    2010-01-01

    Infrared heterodyne spectra of isotopic CO2 in the Martian atmosphere were obtained using the Goddard Heterodyne Instrument for Planetary Wind and Composition, HIPWAC, which was interfaced with the 3-meter telescope at the NASA Infrared Telescope Facility- Spectra were colle cted at a resolution of lambda/delta lambda=10(exp 7). Absorption fea tures of the CO2 isotopologues have been identified from which isotop ic ratios of oxygen have been determined. The isotopic ratios O-17/O -16 and O-18/O-16 in the Martian atmosphere can be related to Martian atmospheric evolution and can be compared to isotopic ratios of oxyg en in the Earth's atmosphere. Isotopic carbon and oxygen are importa nt constraints on any theory for the erosion of the Martian primordia l atmosphere and the interaction between the atmosphere and surface o r subsurface chemical reservoirs. This investigation explored the pr esent abundance of the stable isotopes of oxygen in Mars' atmospheric carbon dioxide by measuring rovibrational line absorption in isotop ic species of CO2 using groundbased infrared heterodyne spectroscopy in the vicinity of the 9.6 micron and 10.6 micron CO2 lasing bands. T he target transitions during this observation were O-18 C-12 O-16 as well as O-178 C-12 O-16 and O-16 C-113 O-16 at higher resolving power of lambda/delta lambda=10(exp 7) and with high signal-to-noise ratio (longer integration time) in order to fully characterize the absorpt ion line profiles. The fully-resolved lineshape of both the strong n ormal-isotope and the weak isotopic CO2 lines were measured simultane ously in a single spectrum.

  1. Mapping the thermal structure and minor species of Venus mesosphere with ALMA submillimeter observations

    Science.gov (United States)

    Piccialli, A.; Moreno, R.; Encrenaz, T.; Fouchet, T.; Lellouch, E.; Widemann, T.

    2017-10-01

    Context. Water vapor and sulfur compounds are key species in the photochemistry of Venus mesosphere. These species, together with mesospheric temperatures, exhibit drastic temporal variations, both on short timescales (diurnal and day-to-day) as well on long timescales, far from being understood. Aims: We targeted CO, SO, HDO and SO2 transitions in the submillimeter range using the Atacama Large Millimeter Array (ALMA) to study their spatial and temporal variations. Methods: Four sets of observations were acquired on different dates in November 2011 during the first ALMA Early Science observation Cycle 0. Venus angular diameter was about 11'' with an illumination factor of 92%, so that mostly the day side of the planet was mapped. Assuming a nominal CO abundance profile, we retrieved vertical temperature profiles over the entire disk as a function of latitude and local time. Temperature profiles were later used to retrieve SO, SO2, and H2O. We used HDO as a tracer for water assuming a D/H enrichment of 200 times the terrestrial value. Results: We derived 3D maps of mesospheric temperatures in the altitude range 70-105 km. SO, SO2, and H2O are characterized by a negligible abundance below 85 km followed by an increase with altitude in the upper mesosphere. Disk-averaged SO abundances present a maximum mixing ratio of 15.0 ± 3.1 ppb on November 26 followed the next day by a minimum value of 9.9 ± 1.2 ppb. Due to a very low S/N, SO2 could only be derived from the disk-averaged spectrum on the first day of observation revealing an abundance of 16.5 ± 4.6 ppb. We found a SO2/SO ratio of 1.5 ± 0.4. Global maps of SO reveal strong variations both with latitude and local time and from day to day with abundance ranging from < 1 to 15 ppb. H2O disk-averages retrievals reveal a steady decrease from November 14 to 27, with the abundance varying from 3.6 ± 0.6 ppm on the first day to 2.9 ± 0.7 ppm on the last day. H2O maps reveal a slightly higher abundance on the evening

  2. New technologies for the detection of millimeter and submillimeter waves

    Energy Technology Data Exchange (ETDEWEB)

    Richards, P.L.; Clarke, J.; Gildemeister, J.M.; Lanting, T.; Lee, A.T.; Myers, M.J.; Schwan, D.; Skidmore, J.T.; Spieler, H.G.; Yoon, Jongsoo

    2001-09-20

    Voltage-biased superconducting bolometers have many operational advantages over conventional bolometer technology including sensitivity, linearity, speed, and immunity from environmental disturbance. A review is given of the Berkeley program for developing this new technology. Developments include fully lithographed individual bolometers in the spiderweb configuration, arrays of 1024 close-packed absorber-coupled bolometers, antenna-coupled bolometers, and a frequency-domain SQUID readout multiplexer.

  3. Reflective Type Small-Angle Sensor Based on Multiple Total Internal Reflections in Heterodyne Interferometry

    Directory of Open Access Journals (Sweden)

    Shinn-Fwu Wang

    2008-12-01

    Full Text Available A reflective type small-angle sensor based on the multiple total internal reflections (MTIRs in heterodyne interferometry is proposed. In the paper, we try to measure the phase difference variation between s- and p-polarizations due to MTIRs. The phase difference variation depends on the incident angle. Therefore, only evaluating the phase difference variation can perform small-angle measurement. The resolution of the method can reach 5.5E-7 radian. The method has some merits, e.g., a simple optical setup, easy operation, high measurement accuracy, high resolution, rapid measurement, and high stability etc. and its feasibility is demonstrated.

  4. New Type Small-angle Sensor Based on the TIR and SPR Theories in Heterodyne Interferomery

    Directory of Open Access Journals (Sweden)

    Shinn-Fwu Wang

    2009-06-01

    Full Text Available In this paper, a new type small-angle sensor based on the total internal reflection (TIR and surface plasmon resonance (SPR theories in heterodyne interferomery is proposed. With the small-displacement sensor, a small rotation angle can be obtained only by measuring the variation in phase difference between s- and p-polarization states. The best theoretical sensitivity of the small-angle sensor is 2x10-4 degree/degree. And its resolution can reach 1x10-7 radian. The sensor has some merits, e.g., a simple optical setup, high resolution, high sensitivity, rapid measurement.

  5. Small-angle Sensor Based on the SPR Technology and Heterodyne Interferomery

    Directory of Open Access Journals (Sweden)

    Shinn-Fwu Wang

    2008-05-01

    Full Text Available A small-angle sensor based on the surface plasmon resonance (SPR technology and heterodyne interferometry is proposed. In the paper, we try to measure the phase difference variation between s and p polarizations due to attenuated total reflection (ATR. The phase difference variation depends on the incident angle. Therefore, only evaluating the phase difference variation can perform small-angle measurement. The resolution of the method can reach 2.4 x 10-7 radian. The method has some merits, e.g., a simple optical setup, easy operation, high measurement accuracy, high resolution, rapid measurement, and high stability etc. And its feasibility is demonstrated.

  6. Homodyne and heterodyne optical interferometry for frequency dependent piezoelectric displacement measurement

    Science.gov (United States)

    Delahoussaye, Keith; Guo, Ruyan; Bhalla, Amar

    2014-09-01

    The electromechanical coupling in piezoelectric materials has been widely studied however a unified view of this interaction as function of frequencies using different measurement techniques has not previously been available. This study examines and compares multiple optical based homodyne and heterodyne interferometry techniques for displacement measurement over a wide range of frequencies and including a comparison made by using a commercial Laser Doppler Vibrometer. Ferroelectric lead titanate PbTiO3 with high ferroelectric strain is studied in this work. Frequency dependence of the electromechanical displacement is obtained using multiple techniques and the emphasis is given to near resonant frequency interrogations.

  7. Multifunctional fiber-optic microwave links based on remote heterodyne detection

    DEFF Research Database (Denmark)

    Gliese, Ulrik Bo; Nielsen, Torben Nørskov; Nielsen, Søren Nørskov

    1998-01-01

    The multifunctionality of microwave links based on remote heterodyne detection (RHD) of signals from a dual-frequency laser transmitter is discussed and experimentally demonstrated in this paper. Typically, direct detection (DD) in conjunction with optical intensity modulation is used to implemen...... carrier to a 9-GHz carrier with penalty-free transmission over 25 km of optical fiber. Finally, the transparent link transmits a standard FM video 7.6-GHz radio-link signal over 25 km of optical fiber without measurable distortion...

  8. Bandwidth coverage of niobium based superconducting tunnel devices

    NARCIS (Netherlands)

    Lodewijk, C.F.J.

    2009-01-01

    The Atacama Large Millimeter/submillimeter Array (ALMA) is an astronomical observatory that is being built on a 5000 m altitude plateau in Chile to perform heterodyne measurements in the frequency range of 30 to 950 GHz. These measurements will reveal the presence of characteristic molecules that

  9. The ALMA Band 9 receiver. Design, construction, characterization, and first light : Design, construction, characterization, and first light

    NARCIS (Netherlands)

    Baryshev, A. M.; Hesper, R.; Mena, F. P.; Klapwijk, T. M.; van Kempen, T. A.; Hogerheijde, M. R.; Jackson, B. D.; Adema, J.; Gerlofsma, G. J.; Bekema, M. E.; Barkhof, J.; de Haan-Stijkel, L. H. R.; van den Bemt, M.; Koops, A.; Keizer, K.; Pieters, C.; Koops van het Jagt, J.; Schaeffer, H.H.A.; Zijlstra, T.; Kroug, M.; Lodewijk, C. F. J.; Wielinga, K.; Boland, W.; de Graauw, M. W. M.; van Dishoeck, E. F.; Jager, H.; Wild, W.

    Aims: We describe the design, construction, and characterization of the Band 9 heterodyne receivers (600-720 GHz) for the Atacama Large Millimeter/submillimeter Array (ALMA). First-light Band 9 data, obtained during ALMA commissioning and science verification phases, are presented as well. Methods:

  10. COMPACT STARBURSTS IN z similar to 3-6 SUBMILLIMETER GALAXIES REVEALED BY ALMA

    NARCIS (Netherlands)

    Ikarashi, Soh; Ivison, R. J.; Caputi, Karina I.; Aretxaga, Itziar; Dunlop, James S.; Hatsukade, Bunyo; Hughes, David H.; Iono, Daisuke; Izumi, Takuma; Kawabe, Ryohei; Kohno, Kotaro; Lagos, Claudia D. P.; Motohara, Kentaro; Nakanishi, Kouichiro; Ohta, Kouji; Tamura, Yoichi; Umehata, Hideki; Wilson, Grant W.; Yabe, Kiyoto; Yun, Min S.

    2015-01-01

    We report the source size distribution, as measured by ALMA millimetric continuum imaging, of a sample of 13 AzTEC-selected submillimeter galaxies (SMGs) at z(phot) similar to 3-6. Their infrared luminosities and star formation rates (SFRs) are L-IR similar to, 2-6 x 10(12) L-circle dot and similar

  11. VizieR Online Data Catalog: Sub-millimeter spectra of 2-hydroxyacetonitrile (Margules+, 2017)

    Science.gov (United States)

    Margules, L.; McGuire, B. A.; Senent, M. L.; Motiyenko, R. A.; Remijan, A.; Guillemin, J. C.

    2017-02-01

    Measured frequencies and residuals from the global fit of the submillimeter-wave data for 2-hydroxyacetonitrile and files used for SPFIT. Detailled explanations on SPFIT could be found at https://www.astro.uni-koeln.de/cdms/pickett (4 data files).

  12. AN ALMA SURVEY OF SUBMILLIMETER GALAXIES IN THE EXTENDED CHANDRA DEEP FIELD SOUTH: NEAR-INFRARED MORPHOLOGIES AND STELLAR SIZES

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chian-Chou; Smail, Ian; Swinbank, A. M.; Simpson, J. M.; Ma, Cheng-Jiun; Alexander, D. M.; Danielson, A. L. R.; Edge, A. C. [Institute for Computational Cosmology, Durham University, South Road, Durham DH1 3LE (United Kingdom); Biggs, A. D.; Ivison, R. J. [European Southern Observatory, Karl Schwarzschild Strasse 2, D-85748 Garching (Germany); Brandt, W. N. [Department of Astronomy and Astrophysics, 525 Davey Lab, Pennsylvania State University, University Park, PA 16802 (United States); Chapman, S. C. [Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS B3H 3J5 (Canada); Coppin, K. E. K. [Centre for Astrophysics Research, Science and Technology Research Institute, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom); Dannerbauer, H. [Institut für Astrophysik, Universität Wien, Türkenschanzstraße 17, A-1180 Wien (Austria); Greve, T. R. [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Karim, A. [Argelander-Institute for Astronomy, Bonn University, Auf dem Hügel 71, D-53121 Bonn (Germany); Menten, Karl M. [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Schinnerer, E.; Walter, F. [Max-Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); Wardlow, J. L. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen (Denmark); and others

    2015-02-01

    We analyze Hubble Space Telescope WFC3/H {sub 160}-band observations of a sample of 48 Atacama Large Millimeter/submillimeter Array detected submillimeter galaxies (SMGs) in the Extended Chandra Deep Field South field, to study their stellar morphologies and sizes. We detect 79% ± 17% of the SMGs in the H {sub 160}-band imaging with a median sensitivity of 27.8 mag, and most (80%) of the nondetections are SMGs with 870 μm fluxes of S {sub 870} < 3 mJy. With a surface brightness limit of μ {sub H} ∼ 26 mag arcsec{sup –2}, we find that 82% ± 9% of the H {sub 160}-band-detected SMGs at z = 1-3 appear to have disturbed morphologies, meaning they are visually classified as either irregulars or interacting systems, or both. By determining a Sérsic fit to the H {sub 160} surface brightness profiles, we derive a median Sérsic index of n = 1.2 ± 0.3 and a median half-light radius of r{sub e} = 4.4{sub −0.5}{sup +1.1} kpc for our SMGs at z = 1-3. We also find significant displacements between the positions of the H {sub 160} component and 870 μm emission in these systems, suggesting that the dusty starburst regions and less-obscured stellar distribution are not colocated. We find significant differences in the sizes and the Sérsic index between our z = 2-3 SMGs and z ∼ 2 quiescent galaxies, suggesting that a major transformation of the stellar light profile is needed in the quenching processes if SMGs are progenitors of the red-and-dead z ∼ 2 galaxies. Given the short-lived nature of SMGs, we postulate that the majority of the z = 2-3 SMGs with S {sub 870} ≳ 2 mJy are early/mid-stage major mergers.

  13. Technology Needs for Far-Infrared, Submillimeter, and Millimeter Missions

    Science.gov (United States)

    Moseley, S. Harvey

    2004-01-01

    SAFIR will: Study the important and relatively unexplored region of the spectrum between 30 and 300 m; Enable the study of galaxy formation and the earliest stage of star formation by revealing regions too enshrouded by dust to be studied by NGST; Be more than 100 times as sensitive as SIRTF or the European [Herschel] mission.SAFIR is projected to cost around $600M total. The decadal review committee recommends that $100M be allocated in this decade to start the SAFIR project, and that additional technology developments be funded separately: Far-Infrared Array Development ($10M ) Refrigerators ($50M ) Large, Lightweight Optics ($80M ). Current developments are also described.

  14. Phase imaging and detection in pseudo-heterodyne scattering scanning near-field optical microscopy measurements.

    Science.gov (United States)

    Moreno, Camilo; Alda, Javier; Kinzel, Edward; Boreman, Glenn

    2017-02-01

    When considering the pseudo-heterodyne mode for detection of the modulus and phase of the near field from scattering scanning near-field optical microscopy (s-SNOM) measurements, processing only the modulus of the signal may produce an undesired constraint in the accessible values of the phase of the near field. A two-dimensional analysis of the signal provided by the data acquisition system makes it possible to obtain phase maps over the whole [0, 2π) range. This requires post-processing of the data to select the best coordinate system in which to represent the data along the direction of maximum variance. The analysis also provides a quantitative parameter describing how much of the total variance is included within the component selected for calculation of the modulus and phase of the near field. The dependence of the pseudo-heterodyne phase on the mean position of the reference mirror is analyzed, and the evolution of the global phase is extracted from the s-SNOM data. The results obtained from this technique compared well with the expected maps of the near-field phase obtained from simulations.

  15. Rapid-scan Fourier-transform coherent anti-Stokes Raman scattering spectroscopy with heterodyne detection.

    Science.gov (United States)

    Hiramatsu, Kotaro; Luo, Yizhi; Ideguchi, Takuro; Goda, Keisuke

    2017-11-01

    High-speed Raman spectroscopy has become increasingly important for analyzing chemical dynamics in real time. To address the need, rapid-scan Fourier-transform coherent anti-Stokes Raman scattering (FT-CARS) spectroscopy has been developed to realize broadband CARS measurements at a scan rate of more than 20,000 scans/s. However, the detection sensitivity of FT-CARS spectroscopy is inherently low due to the limited number of photons detected during each scan. In this Letter, we show our experimental demonstration of enhanced sensitivity in rapid-scan FT-CARS spectroscopy by heterodyne detection. Specifically, we implemented heterodyne detection by superposing the CARS electric field with an external local oscillator (LO) for their interference. The CARS signal was amplified by simply increasing the power of the LO without the need for increasing the incident power onto the sample. Consequently, we achieved enhancement in signal intensity and the signal-to-noise ratio by factors of 39 and 5, respectively, compared to FT-CARS spectroscopy with homodyne detection. The sensitivity-improved rapid-scan FT-CARS spectroscopy is expected to enable the sensitive real-time observation of chemical dynamics in a broad range of settings, such as combustion engines and live biological cells.

  16. A method of measuring micro-impulse with torsion pendulum based on multi-beam laser heterodyne

    Science.gov (United States)

    Li, Yan-Chao; Wang, Chun-Hui

    2012-02-01

    In this paper, we propose a novel method of multi-beam laser heterodyne measurement for micro-impulse. The measurement of the micro-impulse, which is converted into the measurement of the small tuning angle of the torsion pendulum, is realized by considering the interaction between pulse laser and working medium. Based on Doppler effect and heterodyne technology, the information regarding the small tuning angle is loaded to the frequency difference of the multi-beam laser heterodyne signal by the frequency modulation of the oscillating mirror, thereby obtaining many values of the small tuning angle after the multi-beam laser heterodyne signal demodulation simultaneously. Processing these values by weighted-average, the small tuning angle can be obtained accurately and the value of the micro-impulse can eventually be calculated. Using Polyvinylchlorid+2%C as a working medium, this novel method is used to simulate the value of the micro-impulse by MATLAB which is generated by considering the interaction between the pulse laser and the working medium, the obtained result shows that the relative error of this method is just 0.5%.

  17. Transient and time-resolved four-wave mixing with collinear pump and probe pulses using the heterodyne technique

    DEFF Research Database (Denmark)

    Mecozzi, A.; Mørk, Jesper

    1998-01-01

    We review the recently proposed heterodyne technique for four-wave mixing experiments with collinear and co-polarized pulses. We discuss issues related to the parameters of the nonlinear dynamics of the sample that can be extracted by this technique....

  18. Hot electron bolometer heterodyne receiver with a 4.7-THz quantum cascade laser as a local oscillator

    NARCIS (Netherlands)

    Kloosterman, J.L.; Hayton, D.J.; Ren, Y.; Kao, T.Y.; Hovenier, J.N.; Gao, J.R.; Klapwijk, T.M.; Hu, Q.; Walker, C.K.; Reno, J.L.

    2013-01-01

    We report on a heterodyne receiver designed to observe the astrophysically important neutral atomic oxygen [OI] line at 4.7448?THz. The local oscillator is a third-order distributed feedback quantum cascade laser operating in continuous wave mode at 4.741?THz. A quasi-optical, superconducting NbN

  19. High Frequency High Spectral Resolution Focal Plane Arrays for AtLAST

    Science.gov (United States)

    Baryshev, Andrey

    2018-01-01

    Large collecting area single dish telescope such as ATLAST will be especially effective for medium (R 1000) and high (R 50000) spectral resolution observations. Large focal plane array is a natural solution to increase mapping speed. For medium resolution direct detectors with filter banks (KIDs) and or heterodyne technology can be employed. We will analyze performance limits of comparable KID and SIS focal plane array taking into account quantum limit and high background condition of terrestrial observing site. For large heterodyne focal plane arrays, a high current density AlN junctions open possibility of large instantaneous bandwidth >40%. This and possible multi frequency band FPSs presents a practical challenge for spatial sampling and scanning strategies. We will discuss phase array feeds as a possible solution, including a modular back-end system, which can be shared between KID and SIS based FPA. Finally we will discuss achievable sensitivities and pixel co unts for a high frequency (>500 GHz) FPAs and address main technical challenges: LO distribution, wire counts, bias line multiplexing, and monolithic vs. discrete mixer component integration.

  20. Direct measurement of additional Ar-H2O vibration-rotation-tunneling bands in the millimeter-submillimeter range

    Science.gov (United States)

    Zou, Luyao; Widicus Weaver, Susanna L.

    2016-06-01

    Three new weak bands of the Ar-H2O vibration-rotation-tunneling spectrum have been measured in the millimeter wavelength range. These bands were predicted from combination differences based on previously measured bands in the submillimeter region. Two previously reported submillimeter bands were also remeasured with higher frequency resolution. These new measurements allow us to obtain accurate information on the Coriolis interaction between the 101 and 110 states. Here we report these results and the associated improved molecular constants.

  1. Laser heterodyne interferometric signal processing method based on rising edge locking with high frequency clock signal.

    Science.gov (United States)

    Zhang, Enzheng; Chen, Benyong; Yan, Liping; Yang, Tao; Hao, Qun; Dong, Wenjun; Li, Chaorong

    2013-02-25

    A novel phase measurement method composed of the rising-edge locked signal processing and the digital frequency mixing is proposed for laser heterodyne interferometer. The rising-edge locked signal processing, which employs a high frequency clock signal to lock the rising-edges of the reference and measurement signals, not only can improve the steepness of the rising-edge, but also can eliminate the error counting caused by multi-rising-edge phenomenon in fringe counting. The digital frequency mixing is realized by mixing the digital interference signal with a digital base signal that is different from conventional frequency mixing with analogue signals. These signal processing can improve the measurement accuracy and enhance anti-interference and measurement stability. The principle and implementation of the method are described in detail. An experimental setup was constructed and a series of experiments verified the feasibility of the method in large displacement measurement with high speed and nanometer resolution.

  2. Fast, high-resolution surface potential measurements in air with heterodyne Kelvin probe force microscopy

    Science.gov (United States)

    Garrett, Joseph L.; Munday, Jeremy N.

    2016-06-01

    Kelvin probe force microscopy (KPFM) adapts an atomic force microscope to measure electric potential on surfaces at nanometer length scales. Here we demonstrate that Heterodyne-KPFM enables scan rates of several frames per minute in air, and concurrently maintains spatial resolution and voltage sensitivity comparable to frequency-modulation KPFM, the current spatial resolution standard. Two common classes of topography-coupled artifacts are shown to be avoidable with H-KPFM. A second implementation of H-KPFM is also introduced, in which the voltage signal is amplified by the first cantilever resonance for enhanced sensitivity. The enhanced temporal resolution of H-KPFM can enable the imaging of many dynamic processes, such as such as electrochromic switching, phase transitions, and device degredation (battery, solar, etc), which take place over seconds to minutes and involve changes in electric potential at nanometer lengths.

  3. Heterodyne mixing of millimetre electromagnetic waves and sub-THz sound in a semiconductor device.

    Science.gov (United States)

    Heywood, Sarah L; Glavin, Boris A; Beardsley, Ryan P; Akimov, Andrey V; Carr, Michael W; Norman, James; Norton, Philip C; Prime, Brian; Priestley, Nigel; Kent, Anthony J

    2016-08-01

    We demonstrate heterodyne mixing of a 94 GHz millimetre wave photonic signal, supplied by a Gunn diode oscillator, with coherent acoustic waves of frequency ~100 GHz, generated by pulsed laser excitation of a semiconductor surface. The mixing takes place in a millimetre wave Schottky diode, and the intermediate frequency electrical signal is in the 1-12 GHz range. The mixing process preserves all the spectral content in the acoustic signal that falls within the intermediate frequency bandwidth. Therefore this technique may find application in high-frequency acoustic spectroscopy measurements, exploiting the nanometre wavelength of sub-THz sound. The result also points the way to exploiting acoustoelectric effects in photonic devices working at sub-THz and THz frequencies, which could provide functionalities at these frequencies, e.g. acoustic wave filtering, that are currently in widespread use at lower (GHz) frequencies.

  4. An empirical correction for moderate multiple scattering in super-heterodyne light scattering

    Science.gov (United States)

    Botin, Denis; Mapa, Ludmila Marotta; Schweinfurth, Holger; Sieber, Bastian; Wittenberg, Christopher; Palberg, Thomas

    2017-05-01

    Frequency domain super-heterodyne laser light scattering is utilized in a low angle integral measurement configuration to determine flow and diffusion in charged sphere suspensions showing moderate to strong multiple scattering. We introduce an empirical correction to subtract the multiple scattering background and isolate the singly scattered light. We demonstrate the excellent feasibility of this simple approach for turbid suspensions of transmittance T ≥ 0.4. We study the particle concentration dependence of the electro-kinetic mobility in low salt aqueous suspension over an extended concentration regime and observe a maximum at intermediate concentrations. We further use our scheme for measurements of the self-diffusion coefficients in the fluid samples in the absence or presence of shear, as well as in polycrystalline samples during crystallization and coarsening. We discuss the scope and limits of our approach as well as possible future applications.

  5. Improving Spectral Results Using Row-by-Row Fourier Transform of Spatial Heterodyne Raman Spectrometer Interferogram.

    Science.gov (United States)

    Barnett, Patrick D; Strange, K Alicia; Angel, S Michael

    2017-06-01

    This work describes a method of applying the Fourier transform to the two-dimensional Fizeau fringe patterns generated by the spatial heterodyne Raman spectrometer (SHRS), a dispersive interferometer, to correct the effects of certain types of optical alignment errors. In the SHRS, certain types of optical misalignments result in wavelength-dependent and wavelength-independent rotations of the fringe pattern on the detector. We describe here a simple correction technique that can be used in post-processing, by applying the Fourier transform in a row-by-row manner. This allows the user to be more forgiving of fringe alignment and allows for a reduction in the mechanical complexity of the SHRS.

  6. Ultrafast chirped optical waveform recording using referenced heterodyning and a time microscope

    Science.gov (United States)

    Bennett, Corey Vincent

    2010-06-15

    A new technique for capturing both the amplitude and phase of an optical waveform is presented. This technique can capture signals with many THz of bandwidths in a single shot (e.g., temporal resolution of about 44 fs), or be operated repetitively at a high rate. That is, each temporal window (or frame) is captured single shot, in real time, but the process may be run repeatedly or single-shot. This invention expands upon previous work in temporal imaging by adding heterodyning, which can be self-referenced for improved precision and stability, to convert frequency chirp (the second derivative of phase with respect to time) into a time varying intensity modulation. By also including a variety of possible demultiplexing techniques, this process is scalable to recoding continuous signals.

  7. Ultrafast chirped optical waveform recorder using referenced heterodyning and a time microscope

    Science.gov (United States)

    Bennett, Corey Vincent [Livermore, CA

    2011-11-22

    A new technique for capturing both the amplitude and phase of an optical waveform is presented. This technique can capture signals with many THz of bandwidths in a single shot (e.g., temporal resolution of about 44 fs), or be operated repetitively at a high rate. That is, each temporal window (or frame) is captured single shot, in real time, but the process may be run repeatedly or single-shot. This invention expands upon previous work in temporal imaging by adding heterodyning, which can be self-referenced for improved precision and stability, to convert frequency chirp (the second derivative of phase with respect to time) into a time varying intensity modulation. By also including a variety of possible demultiplexing techniques, this process is scalable to recoding continuous signals.

  8. On the Performance of Multihop Heterodyne FSO Systems With Pointing Errors

    KAUST Repository

    Zedini, Emna

    2015-03-30

    This paper reports the end-to-end performance analysis of a multihop free-space optical system with amplify-and-forward (AF) channel-state-information (CSI)-assisted or fixed-gain relays using heterodyne detection over Gamma–Gamma turbulence fading with pointing error impairments. In particular, we derive new closed-form results for the average bit error rate (BER) of a variety of binary modulation schemes and the ergodic capacity in terms of the Meijer\\'s G function. We then offer new accurate asymptotic results for the average BER and the ergodic capacity at high SNR values in terms of simple elementary functions. For the capacity, novel asymptotic results at low and high average SNR regimes are also obtained via an alternative moments-based approach. All analytical results are verified via computer-based Monte-Carlo simulations.

  9. Experimental set-up for a pulsed CO2 laser rangefinder with heterodyne detection

    Science.gov (United States)

    Bloem, J.

    1990-08-01

    The creation of a pulsed CO2 laser range finder with heterodyne detection is described. The range finder uses a hybrid CW-TEA (Continuous Wave-Transversely Excited Atmospheric pressure) laser as emitter and an RF laser as local oscillator. The laser stabilization is described. The frequency offset between the transmitted laser pulse and the local oscillator laser is locked at 20 MHz. The long term (20 to 30 min) variation of this offset frequency is limited to 50 kHz. The effects of pulsing on this stabilization were eliminated. The signal processing was started. A rough model of the laser pulse and its frequency characteristics was developed. An AM demodulator was developed to determine the envelope of the reflected pulses. The system created can be used to measure the range to (and in the future also the speed of) diffuse reflecting targets.

  10. Development of Spatial Heterodyne Spectroscopy Measurements for the C-2W Plasma Expansion Divertor

    Science.gov (United States)

    Sheftman, Daniel; Matsumoto, Tadafumi; Thompson, Matthew; Tri Alpha Energy Team

    2017-10-01

    Accurate operation and high performance of the open field line plasma surrounding the Field Reversed Configuration (FRC) is crucial to achieving the goals of successful temperature ramp up and confinement improvement on C-2W. Attributes such as the outflow velocity and temperature of charge exchange or impurity ions can be measured through spectroscopic methods. However, light throughput is severely limited due to the low plasma density inside the divertors where the plasma expands rapidly before terminating on biasing plates. A field widened spatial heterodyne spectrometer was developed in order to address the challenge of making accurate spectroscope measurements on the diffuse plasma. Design of a prototype of this spectrometer, including lab calibration and spectral line measurements performed on a compact toroid injector test stand, will be presented.

  11. Optical intensity modulation direct detection versus heterodyne detection: A high-SNR capacity comparison

    KAUST Repository

    Chaaban, Anas

    2016-09-15

    An optical wireless communications system which employs either intensity-modulation and direct-detection (IM-DD) or heterodyne detection (HD) is considered. IM-DD has lower complexity and cost than HD, but on the other hand, has lower capacity. It is therefore interesting to investigate the capacity gap between the two systems. The main focus of this paper is to investigate this gap at high SNR. Bounds on this gap are established for two cases: between IM-DD and HD, and between IM-DD and an HD-PAM which is an HD system employing pulse-amplitude modulation (PAM). While the gap between IM-DD and HD increases as the signal-to-noise ratio (SNR) increases, the gap between IM-DD and an HD-PAM is upper bounded by a constant at high SNR. © 2015 IEEE.

  12. A laser interferometer for measuring straightness and its position based on heterodyne interferometry.

    Science.gov (United States)

    Chen, Benyong; Zhang, Enzheng; Yan, Liping; Li, Chaorong; Tang, Wuhua; Feng, Qibo

    2009-11-01

    Not only the magnitude but also the position of straightness errors are of concern to users. However, current laser interferometers used for measuring straightness seldom give the relative position of the straightness error. To solve this problem, a laser interferometer for measuring straightness and its position based on heterodyne interferometry is proposed. The optical configuration of the interferometer is designed and the measurement principle is analyzed theoretically. Two experiments were carried out. The first experiment verifies the validity and repeatability of the interferometer by measuring a linear stage. Also, the second one for measuring a flexure-hinge stage demonstrates that the interferometer is capable of nanometer measurement accuracy. These results show that this interferometer has advantages of simultaneously measuring straightness error and the relative position with high precision, and a compact structure.

  13. THE SCUBA-2 COSMOLOGY LEGACY SURVEY: ALMA RESOLVES THE REST-FRAME FAR-INFRARED EMISSION OF SUB-MILLIMETER GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, J. M.; Smail, Ian; Swinbank, A. M.; Chen, Chian-Chou; Danielson, A. L. R.; Edge, A. C.; Ma, C.-J. [Institute for Computational Cosmology, Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom); Almaini, O.; Conselice, C.; Hartley, W. G.; Lani, C. [School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom); Blain, A. W. [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Bremer, M. N.; Coppin, K. E. K. [School of Physics, HH Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Chapman, S. C. [Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS B3H 3J5 (Canada); Dunlop, J. S.; Ivison, R. J. [Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford HIll, Edinburgh EH9 3HJ (United Kingdom); Farrah, D. [Department of Physics, Virginia Tech, Blacksburg, VA 24061 (United States); Geach, J. E. [Centre for Astrophysics Research, Science and Technology Research Institute, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom); Karim, A., E-mail: j.m.simpson@dur.ac.uk [Argelander-Institute for Astronomy, Bonn University, Auf dem Hügel 71, D-53121 Bonn (Germany); and others

    2015-01-20

    We present high-resolution (0.''3) Atacama Large Millimeter Array 870 μm imaging of 52 sub-millimeter galaxies (SMGs) in the Ultra Deep Survey field to investigate the size and morphology of the sub-millimeter (sub-mm) emission on 2-10 kpc scales. We derive a median intrinsic angular size of FWHM = 0.''30 ± 0.''04 for the 23 SMGs in the sample detected at a signal-to-noise ratio (S/N) >10. Using the photometric redshifts of the SMGs we show that this corresponds to a median physical half-light diameter of 2.4 ± 0.2 kpc. A stacking analysis of the SMGs detected at S/N <10 shows they have sizes consistent with the 870 μm bright SMGs in the sample. We compare our results to the sizes of SMGs derived from other multi-wavelength studies, and show that the rest-frame ∼250 μm sizes of SMGs are consistent with studies of resolved {sup 12}CO (J = 3-2 to 7-6) emission lines, but that sizes derived from 1.4 GHz imaging appear to be approximately two times larger on average, which we attribute to cosmic ray diffusion. The rest-frame optical sizes of SMGs are around four times larger than the sub-millimeter sizes, indicating that the star formation in these galaxies is compact relative to the pre-existing stellar distribution. The size of the starburst region in SMGs is consistent with the majority of the star formation occurring in a central region, a few kiloparsecs in extent, with a median star formation rate surface density of 90 ± 30 M {sub ☉} yr{sup –1} kpc{sup –2}, which may suggest that we are witnessing an intense period of bulge growth in these galaxies.

  14. Ground-Based Submillimeter Spectroscopic Cosmological Surveys and Synergies with Space FIR Surveys

    Science.gov (United States)

    Spinoglio, Luigi

    2018-01-01

    To study the dust obscured processes of both star formation and black hole accretion during galaxy evolution and establish their role, as well as their mutual feedback processes, rest frame IR to submillimeter spectroscopy is needed. At these frequencies dust extinction is at its minimum and a variety of atomic and molecular transitions, tracing most astrophysical domains, occur. A large ground based submillimeter telescope with a large field of view and high sensitivity in the TeraHertz domain will pave the way of future FIR space telescope missions, such as SPICA in the late 2020's and the Origins Telescope later. I will present predictions demonstrating the synergies of such instruments to fully understand galaxy evolution, during its obscured phase, which has built most of the stellar populations in galaxies.

  15. Mu-Spec - A High Performance Ultra-Compact Photon Counting spectrometer for Space Submillimeter Astronomy

    Science.gov (United States)

    Moseley, H.; Hsieh, W.-T.; Stevenson, T.; Wollack, E.; Brown, A.; Benford, D.; Sadleir; U-Yen, I.; Ehsan, N.; Zmuidzinas, J.; hide

    2011-01-01

    We have designed and are testing elements of a fully integrated submillimeter spectrometer based on superconducting microstrip technology. The instrument can offer resolving power R approximately 1500, and its high frequency cutoff is set by the gap of available high performance superconductors. All functions of the spectrometer are integrated - light is coupled to the microstrip circuit with a planar antenna, the spectra discrimination is achieved using a synthetic grating, orders are separated using planar filter, and detected using photon counting MKID detector. This spectrometer promises to revolutionize submillimeter spectroscopy from space. It replaces instruments with the scale of 1m with a spectrometer on a 10 cm Si wafer. The reduction in mass and volume promises a much higher performance system within available resource in a space mission. We will describe the system and the performance of the components that have been fabricated and tested.

  16. A Heterodyne-based Method for Measuring Object Movement Speed and Vibration Parameters

    Directory of Open Access Journals (Sweden)

    M. A. Kostromin

    2015-01-01

    Full Text Available Now, in the industry and science, laser methods and tools are widely used to measure various parameters of objects and environment. Among them is distinguished the method of a heterodyne interferometry allowing real time measurements of fairly high accuracy. However, there is an essential shortcoming in this method. It is rather narrow range of measurements because a period of the wave-interference pattern is commensurable with the light wavelength. Therefore, for measurement of parameters of extended objects this work offers a method, which allows us to form the period wave-interference pattern commensurable with the object sizes using two channels of measurement, i.e. rough and exact, thereby providing a wide range and high accuracy of measurement. The article considers the offered method application to measure a movement speed and vibration parameters of the object and shows its advantage. It describes a structure of the heterodyne-based meter of the cross speed of object movement using the offered method where, as a result of the reflector cross movement, the phase of interfering beams is changed because the wave-interference pattern will be displaced with respect to the optoelectronic sensor slit. The paper defines efficiently working borders of this method for measuring object speed. It is found that to measure the amplitude of vibrations it is determined in this case by calculating the Bessel function transitions through zero. Thus, for disambiguation in determination of the amplitude size rather complicated equipment is demanded. It is shown that the offered method allows us to take absolute measurements of amplitude and frequency of vibrations along with simplified implementation. The calculations show that for the real speeds of the object movement this method, as compared to a known Doppler method, will have the higher sensitivity, which is easily regulated in a wide range by changing the frequency to the cross speeds of the movement

  17. Human brain diffusion tensor imaging at submillimeter isotropic resolution on a 3Tesla clinical MRI scanner.

    Science.gov (United States)

    Chang, Hing-Chiu; Sundman, Mark; Petit, Laurent; Guhaniyogi, Shayan; Chu, Mei-Lan; Petty, Christopher; Song, Allen W; Chen, Nan-kuei

    2015-09-01

    The advantages of high-resolution diffusion tensor imaging (DTI) have been demonstrated in a recent post-mortem human brain study (Miller et al., NeuroImage 2011;57(1):167-181), showing that white matter fiber tracts can be much more accurately detected in data at a submillimeter isotropic resolution. To our knowledge, in vivo human brain DTI at a submillimeter isotropic resolution has not been routinely achieved yet because of the difficulty in simultaneously achieving high resolution and high signal-to-noise ratio (SNR) in DTI scans. Here we report a 3D multi-slab interleaved EPI acquisition integrated with multiplexed sensitivity encoded (MUSE) reconstruction, to achieve high-quality, high-SNR and submillimeter isotropic resolution (0.85×0.85×0.85mm(3)) in vivo human brain DTI on a 3Tesla clinical MRI scanner. In agreement with the previously reported post-mortem human brain DTI study, our in vivo data show that the structural connectivity networks of human brains can be mapped more accurately and completely with high-resolution DTI as compared with conventional DTI (e.g., 2×2×2mm(3)). Copyright © 2015 Elsevier Inc. All rights reserved.

  18. ALMACAL I: First Dual-band Number Counts from a Deep and Wide ALMA Submillimeter Survey, Free from Cosmic Variance

    Science.gov (United States)

    Oteo, I.; Zwaan, M. A.; Ivison, R. J.; Smail, I.; Biggs, A. D.

    2016-05-01

    We have exploited ALMA calibration observations to carry out a novel, wide, and deep submillimeter (submm) survey, almacal. These calibration data comprise a large number of observations of calibrator fields in a variety of frequency bands and array configurations. By gathering together data acquired during multiple visits to many ALMA calibrators, it is possible to reach noise levels which allow the detection of faint, dusty, star-forming galaxies (DSFGs) over a significant area. In this paper, we outline our survey strategy and report the first results. We have analyzed data for 69 calibrators, reaching depths of ˜25 μJy beam-1 at sub-arcsec resolution. Adopting a conservative approach based on ≥5σ detections, we have found 8 and 11 DSFGs in ALMA bands 6 and 7, respectively, with flux densities S 1.2 mm ≥ 0.2 mJy. The faintest galaxies would have been missed by even the deepest Herschel surveys. Our cumulative number counts have been determined independently at 870 μm and 1.2 mm from a sparse sampling of the astronomical sky, and are thus relatively free of cosmic variance. The counts are lower than reported previously by a factor of at least 2×. Future analyses will yield large, secure samples of DSFGs with redshifts determined via the detection of submm spectral lines. Uniquely, our strategy then allows for morphological studies of very faint DSFGs—representative of more normal star-forming galaxies than conventional submm galaxies—in fields where self-calibration is feasible, yielding milliarcsecond spatial resolution.

  19. Design and Fabrication of a Two-Dimensional Superconducting Pop-up Bolometer Array

    Science.gov (United States)

    Benford, Dominic J.; Staguhn, Johannes G.; Chervenak, James A.; Allen, Christine A.; Moseley, S. Harvey; Irwin, Kent D.; Stacey, Gordon J.; Page, Lyman A.

    2004-01-01

    We have been developing an architecture for producing large format, two dimensional arrays of close-packed bolometers, which will enable submillimeter cameras and spectrometers to obtain images and spectra orders of magnitude faster than present instruments. The low backgrounds achieved in these instruments require very sensitive detectors with NEPs of order 5 x 10(exp -18) W/square root of Hz. Superconducting transition edge sensor bolometers can be close-packed using the Pop-up Detector (PUD) format, and SQUID multiplexers operating at the detector base temperature can be intimately coupled to them. The array unit cell is 8 x 32 pixels, using 32- element detector and multiplexer components. We have fabricated an engineering model array with this technology which features a very compact, modular approach for large format arrays. We report on the production of the 32-element components for the arrays. Planned instruments using this array architecture include the Submillimeter and Far-InfraRed Experiment (SAFIRE) on the SOFIA airborne observatory, the South Pole Imaging Fabry-Perot Interferometer (SPIFI) for the AST/RO observatory, the Millimeter Bolometer Camera for the Atacama Cosmology Telescope (MBC/ACT), and the Redshift (Z) Early Universe Spectrometer (ZEUS j.

  20. Coherent self-heterodyne detection of spontaneously Brillouin-scattered light waves in a single-mode fiber

    Science.gov (United States)

    Shimizu, Kaoru; Horiguchi, Tsuneo; Koyamada, Yahei; Kurashima, Toshio

    1993-02-01

    Time-domain reflectometry of spontaneous Brillouin scattering in a single-mode optical fiber is performed with a coherent self-heterodyne detection system containing a recently proposed external frequency translator and a single light-wave source. The light wave is divided into probe and reference light waves. The frequency of the probe light wave is upconverted by the translator by an amount approximately equal to the Brillouin frequency shift. The frequency-converted probe is launched into the fiber and spontaneously Brillouin scattered. As the frequency of the scattered probe is downconverted to near that of the reference light wave, coherent self-heterodyne detection of spontaneous Brillouin scattering becomes possible without having to use a fast-speed detector.

  1. Tunable diode laser heterodyne spectrometer for balloon-borne solar radiometry in the stratosphere. [Absorption spectroscopy analysis of nitric oxide

    Energy Technology Data Exchange (ETDEWEB)

    Hackett, C.E.

    1977-04-01

    A wavelength tunable infrared laser heterodyne spectrometer was taken into the stratosphere as part of the instrumentation package on board the stratospheric scientific research balloon, STRATCOM VI, in order to obtain high-resolution atmospheric absorption spectra of nitric oxide and water vapor by measurement of the attenuation of the solar radiance at approximately 5.24 microns. This report describes the development of this instrument system and the experimentation that characterized its performance.

  2. Band-1 receiver front-end cartridges for Atacama Large Millimeter/submillimeter Array (ALMA): design and development toward production

    Science.gov (United States)

    Hwang, Yuh-Jing; Chiong, Chau-Ching; Huang, Yau-De; Huang, Chi-Den; Liu, Ching-Tang; Kuo, Yue-Fang; Weng, Shou-Hsien; Ho, Chin-Ting; Chiang, Po-Han; Wu, Hsiao-Ling; Chang, Chih-Cheng; Jian, Shou-Ting; Lee, Chien-Feng; Lee, Yi-Wei; Pospieszalski, Marian; Henke, Doug; Finger, Ricardo; Tapia, Valeria; Gonzalez, Alvaro

    2016-07-01

    The ALMA Band-1 receiver front-end prototype cold and warm cartridge assemblies, including the system and key components for ALMA Band-1 receivers have been developed and two sets of prototype cartridge were fully tested. The measured aperture efficiency for the cold receiver is above the 80% specification except for a few frequency points. Based on the cryogenically cooled broadband low-noise amplifiers provided by NRAO, the receiver noise temperature can be as low as 15 - 32K for pol-0 and 17 - 30K for pol-1. Other key testing items are also measured. The receiver beam pattern is measured, the results is well fit to the simulation and design. The pointing error extracted from the measured beam pattern indicates the error is 0.1 degree along azimuth and 0.15 degree along elevation, which is well fit to the specification (smaller than 0.4 degree). The equivalent hot load temperature for 5% gain compression is 492 - 4583K, which well fit to the specification of 5% with 373K input thermal load. The image band suppression is higher than 30 dB typically and the worst case is higher than 20 dB for 34GHz RF signal and 38GHz LO signal, which is all higher than 7 dB required specification. The cross talk between orthogonal polarization is smaller than -85 dB based on present prototype LO. The amplitude stability is below 2.0 x 10-7 , which is fit to the specification of 4.0 x 10-7 for timescales in the range of 0.05 s ≤ T ≤ 100 s. The signal path phase stability measured is smaller than 5 fs, which is smaller than 22 fs for Long term (delay drift) 20 s ≤ T power level is -28 to -30.5 dBm with 300K input load. The measured IF output power flatness is less than 5.6 dB for 2GHz window, and 1.3dB for 31MHz window. The first batch of prototype cartridges will be installed on site for further commissioning on July of 2017.

  3. Greenhouse Gas Concentration Data Recovery Algorithm for a Low Cost, Laser Heterodyne Radiometer

    Science.gov (United States)

    Miller, J. H.; Melroy, H.; Ott, L.; McLinden, M. L.; Holben, B. N.; Wilson, E. L.

    2012-12-01

    The goal of a coordinated effort between groups at GWU and NASA GSFC is the development of a low-cost, global, surface instrument network that continuously monitors three key carbon cycle gases in the atmospheric column: carbon dioxide (CO2), methane (CH4), carbon monoxide (CO), as well as oxygen (O2) for atmospheric pressure profiles. The network will implement a low-cost, miniaturized, laser heterodyne radiometer (mini-LHR) that has recently been developed at NASA Goddard Space Flight Center. This mini-LHR is designed to operate in tandem with the passive aerosol sensor currently used in AERONET (a well established network of more than 450 ground aerosol monitoring instruments worldwide), and could be rapidly deployed into this established global network. Laser heterodyne radiometry is a well-established technique for detecting weak signals that was adapted from radio receiver technology. Here, a weak light signal, that has undergone absorption by atmospheric components, is mixed with light from a distributed feedback (DFB) telecommunications laser on a single-mode optical fiber. The RF component of the signal is detected on a fast photoreceiver. Scanning the laser through an absorption feature in the infrared, results in a scanned heterodyne signal in the RF. Deconvolution of this signal through the retrieval algorithm allows for the extraction of altitude contributions to the column signal. The retrieval algorithm is based on a spectral simulation program, SpecSyn, developed at GWU for high-resolution infrared spectroscopies. Variations in pressure, temperature, composition, and refractive index through the atmosphere; that are all functions of latitude, longitude, time of day, altitude, etc.; are modeled using algorithms developed in the MODTRAN program developed in part by the US Air Force Research Laboratory. In these calculations the atmosphere is modeled as a series of spherically symmetric shells with boundaries specified at defined altitudes. Temperature

  4. Greenhouse Gas Concentration Data Recovery Algorithm for a Low Cost, Laser Heterodyne Radiometer

    Science.gov (United States)

    Miller, J. Houston; Melroy, Hilary R.; Ott, Lesley E.; Mclinden, Matthew L.; Holben, Brent; Wilson, Emily L.

    2012-01-01

    The goal of a coordinated effort between groups at GWU and NASA GSFC is the development of a low-cost, global, surface instrument network that continuously monitors three key carbon cycle gases in the atmospheric column: carbon dioxide (CO2), methane (CH4), carbon monoxide (CO), as well as oxygen (O2) for atmospheric pressure profiles. The network will implement a low-cost, miniaturized, laser heterodyne radiometer (mini-LHR) that has recently been developed at NASA Goddard Space Flight Center. This mini-LHR is designed to operate in tandem with the passive aerosol sensor currently used in AERONET (a well established network of more than 450 ground aerosol monitoring instruments worldwide), and could be rapidly deployed into this established global network. Laser heterodyne radiometry is a well-established technique for detecting weak signals that was adapted from radio receiver technology. Here, a weak light signal, that has undergone absorption by atmospheric components, is mixed with light from a distributed feedback (DFB) telecommunications laser on a single-mode optical fiber. The RF component of the signal is detected on a fast photoreceiver. Scanning the laser through an absorption feature in the infrared, results in a scanned heterodyne signal io the RF. Deconvolution of this signal through the retrieval algorithm allows for the extraction of altitude contributions to the column signal. The retrieval algorithm is based on a spectral simulation program, SpecSyn, developed at GWU for high-resolution infrared spectroscopies. Variations io pressure, temperature, composition, and refractive index through the atmosphere; that are all functions of latitude, longitude, time of day, altitude, etc.; are modeled using algorithms developed in the MODTRAN program developed in part by the US Air Force Research Laboratory. In these calculations the atmosphere is modeled as a series of spherically symmetric shells with boundaries specified at defined altitudes. Temperature

  5. Measurement of the modulation transfer function of x-ray scintillators via heterodyne speckles (Conference Presentation)

    Science.gov (United States)

    Manfredda, Michele; Giglio, Marzio

    2016-09-01

    The approach can be seen as the optical transposition of what is done in electronics, when a system is fed with a white noise (the input signal autocorrelation is a Diract-delta) and the autocorrelation of the the output signal is then taken, thus yielding the Point Spread Function (PSF) of the system (which is the Fourier Transform of the MTF). In the realm of optics, the tricky task consists in the generation and handling of such a suitable random noise, which must be produced via scattering. Ideally, pure 2D white noise (random superposition of sinusoidal intensity modulation at all spatial frequencies in all the diractions) would be produced by ideal point-like scatterers illuminated with completely coherent radiation: interference between scattered waves would generate high-frequency fringes, realizing the sought noise signal. Practically, limited scatterer size and limited coherence properties of radiation introduce a limitation in the spatial bandwidth of the illuminating field. Whereas information about particle-size effect can be promptly obtained from the form factor of the sample used, which is very well known in the case of spherical particles, the information about beam coherence, in general, is usally not known with adequate accuracy, especially at the x-ray wavelengths. In the particular configuration used, speckles are produced by interfering the scattered waves with the strong transmitted beam, (heterodyne speckles), contrarily to the very common case where speckles are produced by the mutual interference between scattered waves (without any transmitted beam acting as local oscillator) (homodyne speckles). In the end the use of an heterodyne speckle field, thanks to its self-referencing scheme, allows to gather, at a fixed distance, response curves spanning a wide range of wavevectors. By crossing the info from curves acquired at few distances (e.g. 2-3) , it is possible to experimentally separate the contribution of spurious effects (such as

  6. Miniaturized Laser Heterodyne Radiometer (LHR) for Measurements of Greenhouse Gases in the Atmospheric Column

    Science.gov (United States)

    Steel, Emily; McLinden, Matthew

    2012-01-01

    This passive laser heterodyne radiometer (LHR) instrument simultaneously measures multiple trace gases in the atmospheric column including carbon dioxide (CO2) and methane (CH4), and resolves their concentrations at different altitudes. This instrument has been designed to operate in tandem with the passive aerosol sensor currently used in AERONET (an established network of more than 450 ground aerosol monitoring instruments worldwide). Because aerosols induce a radiative effect that influences terrestrial carbon exchange, simultaneous detection of aerosols with these key carbon cycle gases offers a uniquely comprehensive measurement approach. Laser heterodyne radiometry is a technique for detecting weak signals that was adapted from radio receiver technology. In a radio receiver, a weak input signal from a radio antenna is mixed with a stronger local oscillator signal. The mixed signal (beat note, or intermediate frequency) has a frequency equal to the difference between the input signal and the local oscillator. The intermediate frequency is amplified and sent to a detector that extracts the audio from the signal. In the LHR instrument described here, sunlight that has undergone absorption by the trace gas is mixed with laser light at a frequency matched to a trace gas absorption feature in the infrared (IR). Mixing results in a beat signal in the RF (radio frequency) region that can be related to the atmospheric concentration. For a one-second integration, the estimated column sensitivities are 0.1 ppmv for CO2, and Greenhouse gases Observational SATellite). The only network that currently measures CO2 and CH4 in the atmospheric column is TCCON (Total Carbon Column Observing Network), and only two of its 16 operational sites are in the United States. TCCON data is used for validation of GOSAT data, and will be used for OCO-2 validation. While these Fourier-transform spectrometers (FTS) can measure the largest range of trace gases, the network is severely limited

  7. Design and fabrication of two-dimensional superconducting bolometer arrays

    Science.gov (United States)

    Benford, Dominic J.; Staguhn, Johannes G.; Stacey, Gordon J.; Page, Lyman; Moseley, S. H., Jr.; Irwin, Kent D.; Chervenak, James A.; Allen, Christine A.

    2004-10-01

    We have been developing an architecture for producing large format, two-dimensional arrays of close-packed bolometers, which will enable far-infrared to millimeter wavelength (lambda=100µm-2mm) cameras and spectrometers to obtain images and spectra orders of magnitude faster than present instruments. The low backgrounds achieved in these instruments require very sensitive detectors with NEPs ranging from 10-17 to 10-19 W/(Hz-1/2). Superconducting transition edge sensor bolometers can be close-packed using the Pop-Up Detector (PUD) format, and SQUID multiplexers operating at the detector base temperature can be intimately coupled to them. The array unit cell is 8x32 pixels, using 32-element detector and multiplexer components. We have fabricated an engineering model array with this technology featuring a very compact, modular approach for large format arrays. We report on the production of the 32-element components for the arrays. Planned instruments using this array architecture include the Submillimeter and Far-InfraRed Experiment (SAFIRE) on the SOFIA airborne observatory, the South Pole Imaging Fabry-Perot Interferometer (SPIFI) for the AST/RO observatory, the Millimeter Bolometer Camera for the Atacama Cosmology Telescope (MBC/ACT), and the Redshift "Z" Early Universe Spectrometer (ZEUS).

  8. Observational Approach to Molecular Cloud Evolutation with the Submillimeter-Wave CI Lines

    Science.gov (United States)

    Oka, T.; Yamamoto, S.

    Neutral carbon atoms (CI) play important roles both in chemistry and cooling processes of interstellar molecular clouds. It is thus crucial to explore its large area distribution to obtain information on formation processes and thermal balance of molecular clouds. However, observations of the submillimeter-wave CI lines have been limited to small areas around some representative objects. We have constructed a 1.2 m submillimeter-wave telescope at the summit of Mt.Fuji. The telescope was designed for the exclusive use of surveying molecular clouds in two submillimeter-wave CI lines, 3 P1 -3 P0 (492GHz) and 3 P2 -3 P1 (809 GHz), of atomic carbon. A superconductor-insulator-superconductor (SIS) mixer receiver was equipped on the Nasmyth focus of the telescope. The receiver noise temperatures [Trx(DSB)] are 300 K and 1000 K for the 492 GHz and the 809 GHz mixers, respectively. The intermediate frequency is centered at 2 GHz, having a 700 MHz bandwidth. An acousto-optical spectrometer (AOS) with 1024 channel outputs is used as a receiver backend. The telescope was installed at Nishi-yasugawara (alt. 3725 m), which is 200 m north of the highest peak, Kengamine (3776 m), in July 1998. It has b en operatede successfully during 4 observing seasons in a remote way from the Hongo campus of the University of Tokyo. We have already observed more than 40 square degrees of the sky with the CI 492 GHz line. The distribution of CI emission is found to be different from those of the 13 CO or C1 8 O emission in some clouds. These differences are discussed in relation to formation processes of molecular clouds.

  9. Sensitivity Study of Ice Crystal Optical Properties in the 874 GHz Submillimeter Band

    Science.gov (United States)

    Tang, Guanglin; Yang, Ping; Wu, Dong L.

    2015-01-01

    Testing of an 874 GHz submillimeter radiometer on meteorological satellites is being planned to improve ice water content retrievals. In this paper we study the optical properties of ice cloud particles in the 874 GHz band. The results show that the bulk scattering and absorption coefficients of an ensemble of ice cloud particles are sensitive to the particle shape and effective diameter, whereas the latter is also sensitive to temperature. The co-polar back scattering cross-section is not sensitive to particle shape, temperature, and the effective diameter in the range of 50200 m.

  10. cluster-in-a-box: Statistical model of sub-millimeter emission from embedded protostellar clusters

    Science.gov (United States)

    Kristensen, Lars E.; Bergin, Edwin A.

    2016-10-01

    Cluster-in-a-box provides a statistical model of sub-millimeter emission from embedded protostellar clusters and consists of three modules grouped in two scripts. The first (cluster_distribution) generates the cluster based on the number of stars, input initial mass function, spatial distribution and age distribution. The second (cluster_emission) takes an input file of observations, determines the mass-intensity correlation and generates outflow emission for all low-mass Class 0 and I sources. The output is stored as a FITS image where the flux density is determined by the desired resolution, pixel scale and cluster distance.

  11. Solar Flash Sub-Millimeter Wave Range Spectrum Part Radiation Modeling

    Directory of Open Access Journals (Sweden)

    V. Yu. Shustikov

    2015-01-01

    Full Text Available Currently, solar flares are under observation on the RT-7.5 radio telescope of BMSTU. This telescope operates in a little-studied range of the spectrum, at wavelengths of 3.2 and 2.2 mm (93 and 140 GHz, thereby providing unique information about parameters of the chromosphere plasma and zone of the temperature minimum. Observations on various instruments provided relatively small amount of data on the radio emission flare at frequencies close to 93 GHz, and at frequency of 140 GHz such observations were not carried out. For these reasons, data collected from the RT-7.5 radio telescope are of high value (Shustikov et al., 2012.This work describes modeling and gives interpretation of the reason for raising flux density spectrum of sub-millimeter radio frequency emission using as an example the GOES flare of class M 5.3 occurred on 04.07.2012 in the active region 11515. This flare was observed on the RT-7.5 radio telescope of BMSTU and was described by Shustikov et al. (2012 and by Smirnova et al. (2013, where it has been suggested that the reason for raising radio frequency emission is a bremsstrahlung of the thermal electrons in the hot plasma of the solar chromosphere. Rough estimates of the plasma temperature at the flare source were obtained.This paper proposes model calculations of the flux density spectrum of the sub-millimeter radio emission based on the gyrosynchrotron Fleischman-Kuznetsov code (Fleishman & Kuznetsov, 2010. Section 1 briefly describes observational data, tools and processing methods used in the work. Section 2 shows results of modeling the flare radio emission. Section 3 discusses results and conclusions.Numerical modeling the sub-millimeter part of the spectrum of the radio flux density for the GOES flare of class M5.3 has been carried out. This flare occurred in the active region 11515 on 04.07.2012. Modeling was based on the observations on the BMSTU’s RT-7.5 radio telescope.The paper draws conclusion based on the

  12. Wavefront Sensing and Control Technology for Submillimeter and Far-Infrared Space Telescopes

    Science.gov (United States)

    Redding, Dave

    2004-01-01

    The NGST wavefront sensing and control system will be developed to TRL6 over the next few years, including testing in a cryogenic vacuum environment with traceable hardware. Doing this in the far-infrared and submillimeter is probably easier, as some aspects of the problem scale with wavelength, and the telescope is likely to have a more stable environment; however, detectors may present small complications. Since this is a new system approach, it warrants a new look. For instance, a large space telescope based on the DART membrane mirror design requires a new actuation approach. Other mirror and actuation technologies may prove useful as well.

  13. Submillimeter-resolution radiography of shielded structures with laser-accelerated electron beams

    Directory of Open Access Journals (Sweden)

    Vidya Ramanathan

    2010-10-01

    Full Text Available We investigate the use of energetic electron beams for high-resolution radiography of flaws embedded in thick solid objects. A bright, monoenergetic electron beam (with energy >100  MeV was generated by the process of laser-wakefield acceleration through the interaction of 50-TW, 30-fs laser pulses with a supersonic helium jet. The high energy, low divergence, and small source size of these beams make them ideal for high-resolution radiographic studies of cracks or voids embedded in dense materials that are placed at a large distance from the source. We report radiographic imaging of steel with submillimeter resolution.

  14. Submillimeter-Resolution Radiography of Shielded Structures with Laser-Accelerated Electron Beams

    Energy Technology Data Exchange (ETDEWEB)

    Ramanathan, Vidya [University of Nebraska, Lincoln; Banerjee, Sudeep [University of Nebraska, Lincoln; Powell, Nathan [University of Nebraska, Lincoln; Cummingham, N. J. [University of Nebraska, Lincoln; Chandler-Smith, Nate [University of Nebraska, Lincoln; Zhao, Kun [University of Nebraska, Lincoln; Brown, Kevin [University of Nebraska, Lincoln; Umstadter, Donald [University of Nebraska, Lincoln; Clarke, Shaun [University of Michigan; Pozzi, Sara [University of Michigan; Beene, James R [ORNL; Vane, C Randy [ORNL; Schultz, David Robert [ORNL

    2010-10-01

    We investigate the use of energetic electron beams for high-resolution radiography of flaws embedded in thick solid objects. A bright, monoenergetic electron beam (with energy >100 MeV) was generated by the process of laser-wakefield acceleration through the interaction of 50-TW, 30-fs laser pulses with a supersonic helium jet. The high energy, low divergence, and small source size of these beams make them ideal for high-resolution radiographic studies of cracks or voids embedded in dense materials that are placed at a large distance from the source. We report radiographic imaging of steel with submillimeter resolution.

  15. Study of optical output couplers for submillimeter wavelength backward-wave oscillators (BWO's)

    Science.gov (United States)

    Cook, Jerry D.; Stankiewicz, Norbert; Podany, Mark

    1989-01-01

    Several scaled experiments of optical output couplers for submillimeter backward-wave oscillators (BWOs). Various designs of planar antennas (Vivaldi horns) lens-feed systems (hyperhemispherical lens) were constructed and tested between 20 and 100 GHz using a spectrum analyzer. The lens system was also tested at 337 GHz using a CO2 pumped FIR laser. It is found that Vivaldi horns have unsatisfactory resonances, perhaps because the horns studied were relatively short. Several techniques to maximize and flatten the frequency response of these horns are presented. The results suggest that alternate coupling schemes are superior to Vivaldi horns.

  16. A compact fiber optics-based heterodyne combined normal and transverse displacement interferometer

    Science.gov (United States)

    Zuanetti, Bryan; Wang, Tianxue; Prakash, Vikas

    2017-03-01

    While Photonic Doppler Velocimetry (PDV) has become a common diagnostic tool for the measurement of normal component of particle motion in shock wave experiments, this technique has not yet been modified for the measurement of combined normal and transverse motion, as needed in oblique plate impact experiments. In this paper, we discuss the design and implementation of a compact fiber-optics-based heterodyne combined normal and transverse displacement interferometer. Like the standard PDV, this diagnostic tool is assembled using commercially available telecommunications hardware and uses a 1550 nm wavelength 2 W fiber-coupled laser, an optical focuser, and single mode fibers to transport light to and from the target. Two additional optical probes capture first-order beams diffracted from a reflective grating at the target free-surface and deliver the beams past circulators and a coupler where the signal is combined to form a beat frequency. The combined signal is then digitized and analyzed to determine the transverse component of the particle motion. The maximum normal velocity that can be measured by this system is limited by the equivalent transmission bandwidth (3.795 GHz) of the combined detector, amplifier, and digitizer and is estimated to be ˜2.9 km/s. Sample symmetric oblique plate-impact experiments are performed to demonstrate the capability of this diagnostic tool in the measurement of the combined normal and transverse displacement particle motion.

  17. Single-beam dielectric-microsphere trapping with optical heterodyne detection

    Science.gov (United States)

    Rider, Alexander D.; Blakemore, Charles P.; Gratta, Giorgio; Moore, David C.

    2018-01-01

    A technique to levitate and measure the three-dimensional position of micrometer-sized dielectric spheres with heterodyne detection is presented. The two radial degrees of freedom are measured by interfering light transmitted through the microsphere with a reference wavefront, while the axial degree of freedom is measured from the phase of the light reflected from the surface of the microsphere. This method pairs the simplicity and accessibility of single-beam optical traps to a measurement of displacement that is intrinsically calibrated by the wavelength of the trapping light and has exceptional immunity to stray light. A theoretical shot noise limit of 1.3 ×10-13 m /√{Hz } for the radial degrees of freedom, and 3.0 ×10-15 m /√{Hz } for the axial degree of freedom can be obtained in the system described. The measured acceleration noise in the radial direction is 7.5 ×10-5 (m /s2) /√{Hz } .

  18. Raman Spectroscopic Detection for Simulants of Chemical Warfare Agents Using a Spatial Heterodyne Spectrometer.

    Science.gov (United States)

    Hu, Guangxiao; Xiong, Wei; Luo, Haiyan; Shi, Hailiang; Li, Zhiwei; Shen, Jing; Fang, Xuejing; Xu, Biao; Zhang, Jicheng

    2018-01-01

    Raman spectroscopic detection is one of the suitable methods for the detection of chemical warfare agents (CWAs) and simulants. Since the 1980s, many researchers have been dedicated to the research of chemical characteristic of CWAs and simulants and instrumental improvement for their analysis and detection. The spatial heterodyne Raman spectrometer (SHRS) is a new developing instrument for Raman detection that appeared in 2011. It is already well-known that SHRS has the characteristics of high spectral resolution, a large field-of-view, and high throughput. Thus, it is inherently suitable for the analysis and detection of these toxic chemicals and simulants. The in situ and standoff detection of some typical simulants of CWAs, such as dimethyl methylphosphonate (DMMP), diisopropyl methylphosphonate (DIMP), triethylphosphate (TEP), diethyl malonate (DEM), methyl salicylate (MES), 2-chloroethyl ethyl sulfide (CEES), and malathion, were tried. The achieved results show that SHRS does have the ability of in situ analysis or standoff detection for simulants of CWAs. When the laser power was set to as low as 26 mW, the SHRS still has a signal-to-noise ratio higher than 5 in in situ detection. The standoff Raman spectra detection of CWAs simulants was realized at a distance of 11 m. The potential feasibility of standoff detection of SHRS for CWAs simulants has been proved.

  19. A compact fiber optics-based heterodyne combined normal and transverse displacement interferometer.

    Science.gov (United States)

    Zuanetti, Bryan; Wang, Tianxue; Prakash, Vikas

    2017-03-01

    While Photonic Doppler Velocimetry (PDV) has become a common diagnostic tool for the measurement of normal component of particle motion in shock wave experiments, this technique has not yet been modified for the measurement of combined normal and transverse motion, as needed in oblique plate impact experiments. In this paper, we discuss the design and implementation of a compact fiber-optics-based heterodyne combined normal and transverse displacement interferometer. Like the standard PDV, this diagnostic tool is assembled using commercially available telecommunications hardware and uses a 1550 nm wavelength 2 W fiber-coupled laser, an optical focuser, and single mode fibers to transport light to and from the target. Two additional optical probes capture first-order beams diffracted from a reflective grating at the target free-surface and deliver the beams past circulators and a coupler where the signal is combined to form a beat frequency. The combined signal is then digitized and analyzed to determine the transverse component of the particle motion. The maximum normal velocity that can be measured by this system is limited by the equivalent transmission bandwidth (3.795 GHz) of the combined detector, amplifier, and digitizer and is estimated to be ∼2.9 km/s. Sample symmetric oblique plate-impact experiments are performed to demonstrate the capability of this diagnostic tool in the measurement of the combined normal and transverse displacement particle motion.

  20. The U.C. Berkeley Space Sciences Laboratory and Department of Physics Submillimeter Receiver

    Science.gov (United States)

    Harris, A. I.; Jaffe, D. T.; Genzel, R.

    1986-01-01

    The UCB submm heterodyne receiver is a complete system for high-resolution astronomical spectroscopy in the 350-micron and 450-micron atmospheric windows. This compact system mounts directly at the Cassegrain focus of large optical and IR telescopes. It consists of a laser local oscillator, open structure mixer, quasi-optical coupling system, a broad-band IF system, and an acoustooptical spectrometer. The local oscillator is a 1-m-long submm laser optically pumped by a CO2 laser. The mixer is a quasi-optical corner-cube antenna structure and Schottky diode. The mixer is currently operated at room temperature, and its performance at 77 K is being evaluated. The system noise temperature is less than 7000 K SSB during observations.

  1. Studying Star and Planet Formation with the Submillimeter Probe of the Evolution of Cosmic Structure

    Science.gov (United States)

    Rinehart, Stephen A.

    2005-01-01

    The Submillimeter Probe of the Evolution of Cosmic Structure (SPECS) is a far- infrared/submillimeter (40-640 micrometers) spaceborne interferometry concept, studied through the NASA Vision Missions program. SPECS is envisioned as a 1-km baseline Michelson interferometer with two 4- meter collecting mirrors. To maximize science return, SPECS will have three operational modes: a photometric imaging mode, an intermediate spectral resolution mode (R approximately equal to 1000-3000), and a high spectral resolution mode (R approximately equal to 3 x 10(exp 5)). The first two of these modes will provide information on all sources within a 1 arcminute field-of-view (FOV), while the the third will include sources in a small (approximately equal to 5 arcsec) FOV. With this design, SPECS will have angular resolution comparable to the Hubble Space Telescope (50 mas) and sensitivity more than two orders of magnitude better than Spitzer (5sigma in 10ks of approximately equal to 3 x 10(exp 7) Jy Hz). We present here some of the results of the recently-completed Vision Mission Study for SPECS, and discuss the application of this mission to future studies of star and planet formation.

  2. Extending the LHC reach for new physics with sub-millimeter displaced vertices

    Science.gov (United States)

    Ito, Hayato; Jinnouchi, Osamu; Moroi, Takeo; Nagata, Natsumi; Otono, Hidetoshi

    2017-08-01

    Particles with a sub-millimeter decay length appear in many models of physics beyond the Standard Model. However, their longevity has been often ignored in their LHC searches and they have been regarded as promptly-decaying particles. In this letter, we show that, by requiring displaced vertices on top of the event selection criteria used in the ordinary search strategies for promptly-decaying particles, we can considerably extend the LHC reach for particles with a decay length of ≳ 100 μm. We discuss a way of reconstructing sub-millimeter displaced vertices by exploiting the same technique used for the primary vertex reconstruction on the assumption that the metastable particles are always pair-produced and their decay products contain high-pT jets. We show that, by applying a cut based on displaced vertices on top of standard kinematical cuts for the search of new particles, the LHC reach can be significantly extended if the decay length is ≳ 100 μm. In addition, we may measure the lifetime of the target particle through the reconstruction of displaced vertices, which plays an important role in understanding the new physics behind the metastable particles.

  3. The status of MUSIC: the multiwavelength sub-millimeter inductance camera

    Science.gov (United States)

    Sayers, Jack; Bockstiegel, Clint; Brugger, Spencer; Czakon, Nicole G.; Day, Peter K.; Downes, Thomas P.; Duan, Ran P.; Gao, Jiansong; Gill, Amandeep K.; Glenn, Jason; Golwala, Sunil R.; Hollister, Matthew I.; Lam, Albert; LeDuc, Henry G.; Maloney, Philip R.; Mazin, Benjamin A.; McHugh, Sean G.; Miller, David A.; Mroczkowski, Anthony K.; Noroozian, Omid; Nguyen, Hien Trong; Schlaerth, James A.; Siegel, Seth R.; Vayonakis, Anastasios; Wilson, Philip R.; Zmuidzinas, Jonas

    2014-08-01

    The Multiwavelength Sub/millimeter Inductance Camera (MUSIC) is a four-band photometric imaging camera operating from the Caltech Submillimeter Observatory (CSO). MUSIC is designed to utilize 2304 microwave kinetic inductance detectors (MKIDs), with 576 MKIDs for each observing band centered on 150, 230, 290, and 350 GHz. MUSIC's field of view (FOV) is 14' square, and the point-spread functions (PSFs) in the four observing bands have 45'', 31'', 25'', and 22'' full-widths at half maximum (FWHM). The camera was installed in April 2012 with 25% of its nominal detector count in each band, and has subsequently completed three short sets of engineering observations and one longer duration set of early science observations. Recent results from on-sky characterization of the instrument during these observing runs are presented, including achieved map- based sensitivities from deep integrations, along with results from lab-based measurements made during the same period. In addition, recent upgrades to MUSIC, which are expected to significantly improve the sensitivity of the camera, are described.

  4. Stratospheric isotopic water profiles from a single submillimeter limb scan by TELIS

    Directory of Open Access Journals (Sweden)

    A. de Lange

    2009-08-01

    Full Text Available Around 490 GHz relatively strong HDO and H218O emission lines can be found in the submillimeter thermal-emission spectrum of the Earth's atmosphere, along with lines of the principal isotopologue of water vapour. These can be used for remote sensing of the rare/principal isotope ratio in the stratosphere. A sensitivity study has been performed for retrieval simulations of water isotopologues from balloon-borne measurements by the limb sounder TELIS (TErahertz and submillimeter LImb Sounder. The study demonstrates the capability of TELIS to determine, from a single limb scan, the profiles for H218O and HDO between 20 km and 37 km with a retrieval error of ≈3 and a spatial resolution of 1.5 km, as determined by the width of the averaging kernel. In addition HDO can be retrieved in the range of 10–20 km, albeit with a strongly deteriorated retrieval error. Expected uncertainties in instrumental parameters have only limited impact on the retrieval results.

  5. A Multiwavelength Study of the Intracluster Medium and the Characterization of the Multiwavelength Sub/millimeter Inductance Camera

    Science.gov (United States)

    Siegel, Seth Robert

    The first part of this thesis combines Bolocam observations of the thermal Sunyaev-Zel'dovich (SZ) effect at 140 GHz with X-ray observations from Chandra, strong lensing data from the Hubble Space Telescope (HST), and weak lensing data from HST and Subaru to constrain parametric models for the distribution of dark and baryonic matter in a sample of six massive, dynamically relaxed galaxy clusters. For five of the six clusters, the full multiwavelength dataset is well described by a relatively simple model that assumes spherical symmetry, hydrostatic equilibrium, and entirely thermal pressure support. The multiwavelength analysis yields considerably better constraints on the total mass and concentration compared to analysis of any one dataset individually. The subsample of five galaxy clusters is used to place an upper limit on the fraction of pressure support in the intracluster medium (ICM) due to nonthermal processes, such as turbulent and bulk flow of the gas. We constrain the nonthermal pressure fraction at r500c to be less than 0.11 at 95% confidence, where r500c refers to radius at which the average enclosed density is 500 times the critical density of the Universe. This is in tension with state-of-the-art hydrodynamical simulations, which predict a nonthermal pressure fraction of approximately 0.25 at r500c for the clusters in this sample. The second part of this thesis focuses on the characterization of the Multiwavelength Sub/millimeter Inductance Camera (MUSIC), a photometric imaging camera that was commissioned at the Caltech Submillimeter Observatory (CSO) in 2012. MUSIC is designed to have a 14 arcminute, diffraction-limited field of view populated with 576 spatial pixels that are simultaneously sensitive to four bands at 150, 220, 290, and 350 GHz. It is well-suited for studies of dusty star forming galaxies, galaxy clusters via the SZ Effect, and galactic star formation. MUSIC employs a number of novel detector technologies: broadband phased-arrays

  6. Terahertz detectors and focal plane arrays

    Science.gov (United States)

    Rogalski, A.; Sizov, F.

    2011-09-01

    Terahertz (THz) technology is one of emerging technologies that will change our life. A lot of attractive applications in security, medicine, biology, astronomy, and non-destructive materials testing have been demonstrated already. However, the realization of THz emitters and receivers is a challenge because the frequencies are too high for conventional electronics and the photon energies are too small for classical optics. As a result, THz radiation is resistant to the techniques commonly employed in these well established neighbouring bands. In the paper, issues associated with the development and exploitation of THz radiation detectors and focal plane arrays are discussed. Historical impressive progress in THz detector sensitivity in a period of more than half century is analyzed. More attention is put on the basic physical phenomena and the recent progress in both direct and heterodyne detectors. After short description of general classification of THz detectors, more details concern Schottky barrier diodes, pair braking detectors, hot electron mixers and field-effect transistor detectors, where links between THz devices and modern technologies such as micromachining are underlined. Also, the operational conditions of THz detectors and their upper performance limits are reviewed. Finally, recent advances in novel nanoelectronic materials and technologies are described. It is expected that applications of nanoscale materials and devices will open the door for further performance improvement in THz detectors.

  7. SCUBA-2 arrays to system interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Duncan, W. E-mail: william.duncan@roe.ac.uk; Audley, D.; Holland, W.; Atkinson, D.; Baillie, T.; Cliffe, M.; Ellis, M.; Gao, X.; Gostick, D.; Hodson, T.; Kelly, D.; MacIntosh, M.; McGregor, H.; Peacocke, T.; Smith, I.; Robson, I.; Walton, A.; Parkes, W.; Dunare, C.; Smith, S.; Terry, J.; Stevenson, T.; Gundlach, A.; Ruthven, A.; Ade, P.; Tucker, C.; Gannaway, F.; Walker, I.; Sudiwala, R.; Woodcraft, A.; Griffin, M.; Bintley, D.; Schulte, E.; Fich, M.; Kycia, J.; Halpern, M.; Molnar, J.; Burger, B.; Naylor, D.; Bastien, P.; Mitchell, G.; Irwin, K.; Hilton, G.; Ullom, J.; Reintsema, C.; Vale, L.; Ferreira, L.; Doriese, W

    2004-03-11

    Submillimeter common user bolometer array (SCUBA)-2 is a wide field sub-mm bolometer camera designed to replace the existing SCUBA instrument on the JCMT in Hawaii. It will be many hundreds of times faster in large area mapping than SCUBA and will also go deeper in a single frame. It will enable the many discoveries of SCUBA to be followed up with deep systematic surveys and help act as a pathfinder for the ALMA interferometer. The key technologies for making the arrays have been demonstrated and will be put together to fabricate the first prototype later this year (2003). The wide field nature of the SCUBA-2 bolometer camera, combined with the diffraction limit at sub-mm wavelengths, leads to physically large focal planes where the issues of stray light control, magnetic shielding, and electrical, thermal and mechanical connection must be carefully addressed in order to realise a successful instrument. We describe the solutions we have adopted for these problem areas.

  8. Studies of Microwave Absorption in Liquids by Optical Heterodyne Detection of Thermally Induced Refractive Index Fluctuations.

    Science.gov (United States)

    Swicord, Mays Littleton

    This work describes the development and implementation of an optical detection method for determining the microwave absorption properties of liquids and liquid suspensions. The method employs a Mach-Zehnder interferometer illuminated with a single-frequency laser to detect fluctuations in the index of refraction of a transparent or semi-transparent substance placed in one arm of the interferometer. The fluctuations are induced by pulses of microwave energy which are introduced into the sample by a specially designed waveguide sample holder. The laser beams from the sample and reference arms of the interferometer recombine on a photodetector resulting in a heterodyne signal. This general method is called Phase Fluctuation Optical Heterodyne (PFLOH) spectroscopy. The method is theoretically capable of detecting refractive index changes of two parts in 10('12) in liquids with greater sensitivity for gases; however, experimental performance is somewhat more limited. Although there is an abundance of microwave spectroscopy literature, virtually all of it is devoted to the absorption properties of gases. There are two reasons for the lack of information on nongaseous substances. First, methods most commonly used on gases, such as absorption ratio methods, are not practical for liquids in this frequency range due to the difficulties of making accurate microwave measurements. PFLOH spectroscopy avoids this difficulty. Second, fine structure (or anomalous dispersion) in the microwave absorption spectra of liquids has been considered nonexistant or at best uninteresting. This level of interest is changing, however, due to possible biological effects of microwave radiation. A number of different types of biological responses have recently been observed and reported in animals exposed to microwave radiation. Some of these effects are clearly responses of the organism to increased local or whole body temperature levels. In some cases the response is not so clearly thermal in

  9. Thermal infrared laser heterodyne spectroradiometry for solar occultation atmospheric CO2 measurements

    Science.gov (United States)

    Hoffmann, Alex; Macleod, Neil A.; Huebner, Marko; Weidmann, Damien

    2016-12-01

    This technology demonstration paper reports on the development, demonstration, performance assessment, and initial data analysis of a benchtop prototype quantum cascade laser heterodyne spectroradiometer, operating within a narrow spectral window of ˜ 1 cm-1 around 953.1 cm-1 in transmission mode and coupled to a passive Sun tracker. The instrument has been specifically designed for accurate dry air total column, and potentially vertical profile, measurements of CO2. Data from over 8 months of operation in 2015 near Didcot, UK, confirm that atmospheric measurements with noise levels down to 4 times the shot noise limit can be achieved with the current instrument. Over the 8-month period, spectra with spectral resolutions of 60 MHz (0.002 cm-1) and 600 MHz (0.02 cm-1) have been acquired with median signal-to-noise ratios of 113 and 257, respectively, and a wavenumber calibration uncertainty of 0.0024 cm-1.Using the optimal estimation method and RFM as the radiative transfer forward model, prior analysis and theoretical benchmark modelling had been performed with an observation system simulator (OSS) to target an optimized spectral region of interest. The selected narrow spectral window includes both CO2 and H2O ro-vibrational transition lines to enable the measurement of dry air CO2 column from a single spectrum. The OSS and preliminary retrieval results yield roughly 8 degrees of freedom for signal (over the entire state vector) for an arbitrarily chosen a priori state with relatively high uncertainty ( ˜ 4 for CO2). Preliminary total column mixing ratios obtained are consistent with GOSAT monthly data. At a spectral resolution of 60 MHz with an acquisition time of 90 s, instrumental noise propagation yields an error of around 1.5 ppm on the dry air total column of CO2, exclusive of biases and geophysical parameters errors at this stage.

  10. Super-Resolution Far-Field Infrared Imaging by Photothermal Heterodyne Imaging.

    Science.gov (United States)

    Li, Zhongming; Aleshire, Kyle; Kuno, Masaru; Hartland, Gregory V

    2017-09-21

    Infrared (IR) imaging provides chemical-specific information without the need for exogenous labels. Conventional far-field IR imaging techniques are diffraction limited, which means an effective spatial resolution of >5 μm with currently available optics. In this article, we present a novel far-field IR imaging technique based on photothermal heterodyne imaging (IR-PHI). In our version of IR-PHI, an IR pump laser excites the sample, causing a small temperature rise that is detected by a counterpropagating visible probe beam. Images and spectra of several different types of soft matter systems (polystyrene beads, thin polymer films, and single Escherichia coli bacterial cells) are presented to demonstrate the sensitivity and versatility of the technique. Importantly, the spatial resolution in the IR-PHI measurements is determined by the visible probe beam: a spatial resolution of 0.3 μm was achieved with a 0.53 μm probe wavelength and a high numerical aperture focusing objective. This is the highest spatial resolution reported to date for far-field IR imaging. Analysis of the experiments shows that for polymer beads in a dry environment, the magnitude of the IR-PHI signal is determined by the scattering cross section of the nano-object at the probe wavelength. This is in contrast to conventional PHI experiments in a heat-transfer medium, where the signal scales as the absorption cross section. This different scaling can be understood through the optical theorem. Our analysis also shows that both thermal expansion and changes in the refractive index of the material are important and that these two effects, in general, counteract each other.

  11. Phased arrays '85

    Science.gov (United States)

    Stiglitz, M. R.

    1985-11-01

    The conference Phased Arrays '85 was held in Bedford, MA, on October 15-18, 1985. It is pointed out that the 15 years between the 1970 and 1985 conferences dedicated to phased array antennas have seen many technological advances. Attention is given to the principle of operation, monolithic phased arrays, active arrays of monopole elements, scan compensated active element patterns, microstrip arrays, time delay technologies for phased array systems, ferrite materials for mm-wave phase shifters, phase-only optimization of phased array excitation by B-quadratic programming, a nearly frequency-independent sidelobe suppression technique for phased arrays, and active impedance effects in low sidelobe and ultrawideband phased arrays.

  12. BER analysis of multi-hop heterodyne FSO systems with fixed gain relays over general Malaga turbulence channels

    KAUST Repository

    Alheadary, Wael Ghazy

    2017-07-20

    This work investigates the end-to-end performance of a free space optical amplify-and-forward (AF) fixed-gain relaying system using heterodyne detection over misaligned general Malaga turbulence channels. More specifically, we present exact closed-form expressions for average bit-error rate achievable spectral efficiency non-adaptive/adaptive modulation schemes by employing generalized power series identity of Meijer\\'s G-function. Moreover, asymptotic closed-form expressions are derived to validate our results at high signal-to-noise ratio. In addition, the analytical results have been presented with compare to range of numerical values.

  13. Angstrom-range optical path-length measurement with a high-speed scanning heterodyne optical interferometer.

    Science.gov (United States)

    Riza, Nabeel A; Arain, Muzammil A

    2003-05-01

    A highly accurate method of optical path-length measurement is introduced by use of a scanning heterodyne optical interferometer with no moving parts. The instrument has demonstrated the potential to measure optical path length at angstrom resolution over continuous thickness in the micrometer range. This optical path length can be used to calculate the thickness of any material if the refractive index is known or to measure the refractive index of the material if the thickness is known. The instrument uses a single acousto-optic device in an in-line ultra-stable reflective geometry to implement rapid scanning in the microsecond domain for thickness measurements of the test medium.

  14. Heterodyne non-demolition measurements on cold atomic samples: towards the preparation of non-classical states for atom interferometry

    Science.gov (United States)

    Bernon, S.; Vanderbruggen, T.; Kohlhaas, R.; Bertoldi, A.; Landragin, A.; Bouyer, P.

    2011-06-01

    We report on a novel experiment to generate non-classical atomic states via quantum non-demolition (QND) measurements on cold atomic samples prepared in a high-finesse ring cavity. The heterodyne technique developed for QND detection exhibits an optical shot-noise limited behavior for local oscillator optical power of a few hundred μW, and a detection bandwidth of several GHz. This detection tool is used in a single pass to follow non-destructively the internal state evolution of an atomic sample when subjected to Rabi oscillations or a spin-echo interferometric sequence.

  15. Heterodyne non-demolition measurements on cold atomic samples: towards the preparation of non-classical states for atom interferometry

    Energy Technology Data Exchange (ETDEWEB)

    Bernon, S; Vanderbruggen, T; Kohlhaas, R; Bertoldi, A; Bouyer, P [Laboratoire Charles Fabry de l' Institut d' Optique, CNRS and Universite Paris-Sud Campus Polytechnique, RD 128, F-91127 Palaiseau cedex (France); Landragin, A, E-mail: simon.bernon@institutoptique.fr [LNE-SYRTE, Observatoire de Paris, CNRS and UPMC 61 avenue de l' Observatoire, F-75014 Paris (France)

    2011-06-15

    We report on a novel experiment to generate non-classical atomic states via quantum non-demolition (QND) measurements on cold atomic samples prepared in a high-finesse ring cavity. The heterodyne technique developed for QND detection exhibits an optical shot-noise limited behavior for local oscillator optical power of a few hundred {mu}W, and a detection bandwidth of several GHz. This detection tool is used in a single pass to follow non-destructively the internal state evolution of an atomic sample when subjected to Rabi oscillations or a spin-echo interferometric sequence.

  16. Heterodyne pump-probe and four-wave mixing in semiconductor optical amplifiers using balanced lock-in detection

    DEFF Research Database (Denmark)

    Borri, Paola; Langbein, Wolfgang; Mørk, Jesper

    1999-01-01

    We demonstrate a new detection scheme for pump-probe and four-wave mixing heterodyne experiments, using balanced detection and a dual-phase lock-in for spectral filtering. The technique allows the use of low repetition-rate laser systems, as is demonstrated on an InGaAsP/InP bulk optical amplifier....... The results for small perturbations are consistent with previous pump-probe experiments reported in literature. Time-resolved four-wave mixing in the absorption regime of the device is measured, and compared with numerical simulations, indicating a 100 fs dephasing time....

  17. A heterodyne interferometer for high resolution translation and tilt measurement as optical readout for the LISA inertial sensor

    Science.gov (United States)

    Schuldt, Thilo; Kraus, Hans-Jürgen; Weise, Dennis; Braxmaier, Claus; Peters, Achim; Johann, Ulrich

    2017-11-01

    The space-based gravitational wave detector LISA (Laser Interferometer Space Antenna) requires a high performance position sensor in order to measure the translation and tilt of the free flying test mass with respect to the LISA optical bench. Here, we present a mechanically highly stable and compact setup of a heterodyne interferometer combined with differential wavefront sensing for the tilt measurement which serves as a demonstrator for an optical readout of the LISA test mass position. First results show noise levels below 1 nm/√Hz and 1 μrad/√Hz, respectively, for frequencies < 10-3 Hz.

  18. A Low-Cost Miniaturized Laser Heterodyne Radiometer (Mini-LHR) for Near-ir Measurements of CO2 and CH4 in the Atmospheric Column

    Science.gov (United States)

    Steel, Emily Wilson

    2016-01-01

    The miniaturized laser heterodyne radiometer (mini-LHR) is a ground-based passive variation of a laser heterodyne radiometer that uses sunlight to measure absorption of CO2 andCH4 in the infrared. Sunlight is collected using collimation optics mounted to an AERONET sun tracker, modulated with a fiber switch and mixed with infrared laser light in a fast photoreciever.The amplitude of the resultant RF (radio frequency) beat signal correlates with the concentration of the gas in the atmospheric column.

  19. Heterodyne grating interferometer based on a quasi-common-optical-path configuration for a two-degrees-of-freedom straightness measurement.

    Science.gov (United States)

    Lee, Ju-Yi; Hsieh, Hung-Lin; Lerondel, Gilles; Deturche, Regis; Lu, Mini-Pei; Chen, Jyh-Chen

    2011-03-20

    We present a heterodyne grating interferometer based on a quasi-common-optical-path (QCOP) design for a two-degrees-of-freedom (DOF) straightness measurement. Two half-wave plates are utilized to rotate the polarizations of two orthogonally polarized beams. The grating movement can be calculated by measuring the phase difference variation in each axis. The experimental results demonstrate that our method has the ability to measure two-DOF straightness and still maintain high system stability. The proposed and demonstrated method, which relies on heterodyne interferometric phase measurement combined with the QCOP configuration, has the advantages of high measurement resolution, relatively straightforward operation, and high system stability.

  20. The JCMT Transient Survey: Detection of Submillimeter Variability in a Class I Protostar EC 53 in Serpens Main

    Science.gov (United States)

    Yoo, Hyunju; Lee, Jeong-Eun; Mairs, Steve; Johnstone, Doug; Herczeg, Gregory J.; Kang, Sung-ju; Kang, Miju; Cho, Jungyeon; The JCMT Transient Team

    2017-11-01

    During the protostellar phase of stellar evolution, accretion onto the star is expected to be variable, but this suspected variability has been difficult to detect because protostars are deeply embedded. In this paper, we describe a submillimeter luminosity burst of the Class I protostar EC 53 in Serpens Main, the first variable found during our dedicated JCMT/SCUBA-2 monitoring program of eight nearby star-forming regions. EC 53 remained quiescent for the first six months of our survey, from 2016 February to August. The submillimeter emission began to brighten in 2016 September, reached a peak brightness of 1.5 times the faint state, and has been decaying slowly since 2017 February. The change in submillimeter brightness is interpreted as dust heating in the envelope, generated by a luminosity increase of the protostar of a factor of ≥4. The 850 μm light curve resembles the historical K-band light curve, which varies by a factor of ˜6 with a 543 period and is interpreted as accretion variability excited by interactions between the accretion disk and a close binary system. The predictable detections of accretion variability observed at both near-infrared and submillimeter wavelengths make the system a unique test-bed, enabling us to capture the moment of the accretion burst and to study the consequences of the outburst on the protostellar disk and envelope.

  1. Observing ice clouds in the submillimeter spectral range: the CloudIce mission proposal for ESA's Earth Explorer 8

    Directory of Open Access Journals (Sweden)

    S. A. Buehler

    2012-07-01

    Full Text Available Passive submillimeter-wave sensors are a way to obtain urgently needed global data on ice clouds, particularly on the so far poorly characterized "essential climate variable" ice water path (IWP and on ice particle size. CloudIce was a mission proposal to the European Space Agency ESA in response to the call for Earth Explorer 8 (EE8, which ran in 2009/2010. It proposed a passive submillimeter-wave sensor with channels ranging from 183 GHz to 664 GHz. The article describes the CloudIce mission proposal, with particular emphasis on describing the algorithms for the data-analysis of submillimeter-wave cloud ice data (retrieval algorithms and demonstrating their maturity. It is shown that we have a robust understanding of the radiative properties of cloud ice in the millimeter/submillimeter spectral range, and that we have a proven toolbox of retrieval algorithms to work with these data. Although the mission was not selected for EE8, the concept will be useful as a reference for other future mission proposals.

  2. TU-F-CAMPUS-T-02: Vernier Picket Fence Test: A Non-Imaging Method to Localize the Radiation Isocenter with Submillimeter Accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Wong, J; Gallagher, K [Oregon Health & Science University, Portland, OR (United States); Oregon State University, Corvallis, OR (United States); Zhang, J [Oregon Health & Science University, Portland, OR (United States)

    2015-06-15

    Purpose: The purpose of this study is to propose a new non-imaging method to localize the radiation isocenter with submillimeter accuracy. Methods: The Vernier picket fence (VPF) is a multileaf collimator (MLC) picket fence sequence in which the fence spacing is 1/N smaller than the detector spacing of the QA phantom, where N is the magnification factor, typically set to 10 or 20. Similar to reading a Vernier caliper, the user can easily achieve the resolution of 1/N of the detector spacing by visually inspecting the maximum signal. To achieve higher accuracy, a Gaussian model was used to interpolate the peak position, which can fall between adjacent detectors. In two separate tests, precise MLC offsets and imprecise couch offsets were applied to a 2D detector array (MapCheck, Sun Nuclear Corp., Melbourne, Florida) to introduce setup errors. Two vertical VPF fields were delivered with collimator angles at 0° and 90° to detect the lateral and longitudinal setup errors, respectively. For a rotational QA phantom, an additional lateral VPF field is needed to detect the vertical setup error for three-dimensional capabilities. Results: With N set to 20 and a detector spacing of 5 mm for MapCheck, the resolution of the VPF’s visual analysis is 0.25 mm. With the Gaussian interpretation, the VPF can achieve an accuracy of 0.02 mm, as shown by the MLC offset test. The couch offset test measured the couch hysteresis and demonstrated that the setup error detected by the VPF differed from the ExacTrac™ (Brainlab AG, Feldkirchen, Germany) optical tracking by 0.055 mm in the lateral direction and 0.041 mm in the longitudinal direction on average. The VPF was also shown to be feasible in the vertical direction as well. Conclusion: This study verified the VPF as a non-imaging method to localize the radiation isocenter with submillimeter accuracy. Funding is in part by the Portland Chapter of the Achievement Rewards for College Scientists. The content is solely the

  3. A Compact 600 GHz Electronically Tunable Vector Measurement System for Submillimeter Wave Imaging

    Science.gov (United States)

    Dengler, Robert; Maiwald, Frank; Siegel, Peter H.

    2006-01-01

    The design of a complete vector measurement system being tested over 560-635 GHz is presented. The topics include: 1) Current State-of-the-Art in Vector Measurements; 2) Submillimeter Active Imaging Requirements; 3) 600 GHz Vector Measurement System; 4) 450 MHz IF Signal; 5) 450 MHz IF signal @ 1 kHz Res. BW; 6) 450 MHz IF Signal Mixed with Shifted 450 MHz Reference Signal; 7) Reference Signal Offset Generator; 8) Cavity Bandpass Filter; 9) Miniature Multistage Helical Filter; 10) X36 450 MHz Multiplier; 11) 600 GHz Test Setup; 12) 600 GHz Transmit Module; 13) 600 GHz Receive Module; 14) Performance Tests: Amplitude Stability & Dynamic Range; 15) Performance Tests: Phase Stability; 16) Stability at Imaging Bandwidths; 17) Phase Measurement Verification; and 18) The Next Step: Imaging.

  4. Estimation of physiological sub-millimeter displacement with CW Doppler radar.

    Science.gov (United States)

    Jia Xu; Xiaomeng Gao; Padasdao, Bryson E; Boric-Lubecke, Olga

    2015-01-01

    Doppler radar physiological sensing has been studied for non-contact detection of vital signs including respiratory and heartbeat rates. This paper presents the first micrometer resolution Wi-Fi band Doppler radar for sub-millimeter physiological displacement measurement. A continuous-wave Doppler radar working at 2.4GHz is used for the measurement. It is intended for estimating small displacements on the body surface resulting from physiological activity. A mechanical mover was used as target, and programmed to conduct sinusoidal motions to simulate pulse motions. Measured displacements were compared with a reference system, which indicates a superior performance in accuracy for having absolute errors less than 10μm, and relative errors below 4%. It indicates the feasibility of highly accurate non-contact monitoring of physiological movements using Doppler radar.

  5. Metal-mesh achromatic half-wave plate for use at submillimeter wavelengths.

    Science.gov (United States)

    Pisano, Giampaolo; Savini, Giorgio; Ade, Peter A R; Haynes, Vic

    2008-11-20

    A metal-mesh achromatic half-wave plate (HWP) has been designed, manufactured, and tested for potential use in millimeter and submillimeter astronomical instruments. The prototype device presented here is based on a 12-grid Shatrow [IEEE Trans. Antennas Propag. 43, 109 (1995)] recipe to operate over the frequency range of 120-180 GHz. Transmission line modeling and finite-element analysis [Ansoft HFSS website: http://www.ansoft.com/hfss/] were used to optimize the design geometrical parameters in terms of the device transmission, reflection, absorption, phase-shift, and cross-polarization as a function of frequency. The resulting prototype device was constructed and characterized using incoherent radiation from a polarizing Fourier transform spectrometer to explore its frequency and polarization behavior. These measurements are shown to be in excellent agreement with the models. Lists of the achieved HWP performance characteristics are reported.

  6. EPR and AFMR of Bi2CuO4 in Submillimeter Wave Region

    Science.gov (United States)

    Ohta, Hitoshi; Yoshida, Kazuhiro; Matsuya, Takashi; Nanba, Takao; Motokawa, Mitsuhiro; Yamada, Kazuyoshi; Endoh, Yasuo; Hosoya, Shoichi

    1992-08-01

    Paramagnetic and antiferromagnetic resonance have been observed in single crystals of Bi2CuO4 in submillimeter wave region using pulsed magnetic fields at temperatures from 4.2 K to 265 K. At the paramagnetic state, g-values have been determined to be g//{=}2.26± 0.01 and g\\bot{=}2.04± 0.01. The angular independent line-widths are 0.37± 0.03 T which is quantitatively explained by the dipole interaction and anisotropic exchange interaction. An antiferromagnetic resonance mode of planer type antiferromagnet has been observed below the Néel temperature and explained by the conventional antiferromagnetic theory.

  7. Submillimeter ionoacoustic range determination for protons in water at a clinical synchrocyclotron

    Science.gov (United States)

    Lehrack, Sebastian; Assmann, Walter; Bertrand, Damien; Henrotin, Sebastien; Herault, Joel; Heymans, Vincent; Vander Stappen, Francois; Thirolf, Peter G.; Vidal, Marie; Van de Walle, Jarno; Parodi, Katia

    2017-09-01

    Proton ranges in water between 145 MeV to 227 MeV initial energy have been measured at a clinical superconducting synchrocyclotron using the acoustic signal induced by the ion dose deposition (ionoacoustic effect). Detection of ultrasound waves was performed by a very sensitive hydrophone and signals were stored in a digital oscilloscope triggered by secondary prompt gammas. The ionoacoustic range measurements were compared to existing range data from a calibrated range detector setup on-site and agreement of better than 1 mm was found at a Bragg peak dose of about 10 Gy for 220 MeV initial proton energy, compatible with the experimental errors. Ionoacoustics has thus the potential to measure the Bragg peak position with submillimeter accuracy during proton therapy, possibly correlated with ultrasound tissue imaging.

  8. A low-cost fabrication method for sub-millimeter wave GaAs Schottky diode

    Science.gov (United States)

    Jenabi, Sarvenaz; Deslandes, Dominic; Boone, Francois; Charlebois, Serge A.

    2017-10-01

    In this paper, a submillimeter-wave Schottky diode is designed and simulated. Effect of Schottky layer thickness on cut-off frequency is studied. A novel microfabrication process is proposed and implemented. The presented microfabrication process avoids electron-beam (e-beam) lithography which reduces the cost. Also, this process provides more flexibility in selection of design parameters and allows significant reduction in the device parasitic capacitance. A key feature of the process is that the Schottky contact, the air-bridges, and the transmission lines, are fabricated in a single lift-off step. This process relies on a planarization method that is suitable for trenches of 1-10 μm deep and is tolerant to end-point variations. The fabricated diode is measured and results are compared with simulations. A very good agreement between simulation and measurement results are observed.

  9. Coupling in reflector arrays

    DEFF Research Database (Denmark)

    Appel-Hansen, Jørgen

    1968-01-01

    In order to reduce the space occupied by a reflector array, it is desirable to arrange the array antennas as close to each other as possible; however, in this case coupling between the array antennas will reduce the reflecting properties of the reflector array. The purpose of the present communic......In order to reduce the space occupied by a reflector array, it is desirable to arrange the array antennas as close to each other as possible; however, in this case coupling between the array antennas will reduce the reflecting properties of the reflector array. The purpose of the present...

  10. Observational Approach to Molecular Cloud Evolution with the Submillimeter CI Lines

    Science.gov (United States)

    Oka, T.; Yamamoto, S.; Mt. Fuji Submillimeter-Wave Telescope Group

    Neutral carbon atoms (CI) play important role both in chemistry and cooling processes of interstellar molecular clouds. It is thus crucial to explore its large area distribution to investigate formation processes and thermal balance of molecular clouds. We have constructed a 1.2 m submillimeter-wave telescope at the summit of Mt.Fuji. The telescope was designed for the exclusive use of surveying molecular clouds in two submillimeter CI lines, 3P1--3P0 (492 GHz) and 3P2--3P1 (809 GHz), of atomic carbon. It has been operated successfully during 4 observing seasons since July 1998 in a remote way from the Hongo campus of the University of Tokyo. We have already revealed large-scale CI 492 GHz distributions of many giant molecular clouds, including Orion MC, Taurus MC, DR15, DR21, NGC2264, M17, W3, W44, W51, Rosette MC, covering more than 40 square degrees of the sky. The distribution of CI 492 GHz emission is found to be different from those of the 13CO or C18O emission in some clouds. We found the spatial order of C+/CO/C from UV sources. This is the general property of the cloud illuminated by intense UV radiation, whereas it is apparently inconsistent with the standard photodissociation region (PDR) picture. We also found CI-rich areas (C/CO˜1) in several dark clouds without strong UV sources. These results are discussed in relation to formation processes of molecular clouds and dense cloud cores.

  11. CORRELATIONS IN THE (SUB)MILLIMETER BACKGROUND FROM ACT Multiplication-Sign BLAST

    Energy Technology Data Exchange (ETDEWEB)

    Hajian, Amir; Battaglia, Nick; Bond, J. Richard [Canadian Institute for Theoretical Astrophysics, University of Toronto, Toronto, ON M5S 3H8 (Canada); Viero, Marco P.; Bock, James J. [California Institute of Technology, Pasadena, CA 91125 (United States); Addison, Graeme [Department of Astrophysics, Oxford University, Oxford, OX1 3RH (United Kingdom); Aguirre, Paula [Departamento de Astronomia y Astrofisica, Facultad de Fisica, Pontificia Universidad Catolica, Casilla 306, Santiago 22 (Chile); Appel, John William; Duenner, Rolando; Essinger-Hileman, Thomas; Fowler, Joseph W.; Hincks, Adam D. [Joseph Henry Laboratories of Physics, Jadwin Hall, Princeton University, Princeton, NJ 08544 (United States); Das, Sudeep; Dunkley, Joanna [Department of Astrophysical Sciences, Peyton Hall, Princeton University, Princeton, NJ 08544 (United States); Devlin, Mark J.; Dicker, Simon R. [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104 (United States); Hughes, John P. [Department of Physics and Astronomy, Rutgers, State University of New Jersey, Piscataway, NJ 08854-8019 (United States); Halpern, Mark [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z4 (Canada); Hasselfield, Matthew [Laboratoire APC, Universite Paris Diderot, 75205 Paris (France); Hilton, Matt [Astrophysics and Cosmology Research Unit, School of Mathematical Sciences, University of KwaZulu-Natal, Durban 4041 (South Africa); and others

    2012-01-01

    We present measurements of the auto- and cross-frequency correlation power spectra of the cosmic (sub)millimeter background at 250, 350, and 500 {mu}m (1200, 860, and 600 GHz) from observations made with the Balloon-borne Large Aperture Submillimeter Telescope (BLAST); and at 1380 and 2030 {mu}m (218 and 148 GHz) from observations made with the Atacama Cosmology Telescope (ACT). The overlapping observations cover 8.6 deg{sup 2} in an area relatively free of Galactic dust near the south ecliptic pole. The ACT bands are sensitive to radiation from the cosmic microwave background, to the Sunyaev-Zel'dovich effect from galaxy clusters, and to emission by radio and dusty star-forming galaxies (DSFGs), while the dominant contribution to the BLAST bands is from DSFGs. We confirm and extend the BLAST analysis of clustering with an independent pipeline and also detect correlations between the ACT and BLAST maps at over 25{sigma} significance, which we interpret as a detection of the DSFGs in the ACT maps. In addition to a Poisson component in the cross-frequency power spectra, we detect a clustered signal at 4{sigma}, and using a model for the DSFG evolution and number counts, we successfully fit all of our spectra with a linear clustering model and a bias that depends only on redshift and not on scale. Finally, the data are compared to, and generally agree with, phenomenological models for the DSFG population. This study demonstrates the constraining power of the cross-frequency correlation technique to constrain models for the DSFGs. Similar analyses with more data will impose tight constraints on future models.

  12. Imaging the environment of a z = 6.3 submillimeter galaxy with SCUBA-2

    Energy Technology Data Exchange (ETDEWEB)

    Robson, E. I.; Holland, W. S. [United Kingdom Astronomy Technology Centre, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Ivison, R. J. [European Space Observatory, Karl Schwarzschild Strasse 2, D-85748 Garching (Germany); Smail, Ian [Institute for Computational Cosmology, Durham University, South Road, Durham DH1 3LE (United Kingdom); Geach, J. E. [Centre for Astrophysics Research, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom); Gibb, A. G. [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); Riechers, D. [Astronomy Department, Cornell University, Ithaca, NY 14853 (United States); Ade, P. A. R. [Astronomy and Instrumentation Group, Cardiff University, Cardiff, Wales CF10 3XQ (United Kingdom); Bintley, D. [Joint Astronomy Centre, 660 North Ahoku Place, University Park, Hilo, HI 96720 (United States); Bock, J. [Jet Propulsion Laboratory, National Aeronautics and Space Administration, Pasadena, CA 91109 (United States); Chapin, E. L. [XMM-Newton Science Operations Centre, European Space Astronomy Centre, Apartado 79, E-28691 Villaneueva de la Canada, Madrid (Spain); Chapman, S. C. [Department of Physics and Atmospheric Science, Dalhousie University, Coburg Road, Halifax B3H 1A6 (Canada); Clements, D. L. [Astrophysics Group, Imperial College London, Blackett Laboratory, Prince Consort Road, London SW7 2AZ (United Kingdom); Conley, A. [Center for Astrophysics and Space Astronomy, 389 UCB, University of Colorado, Boulder, CO 80309 (United States); Cooray, A. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Dunlop, J. S. [Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Farrah, D., E-mail: rob.ivison@gmail.com [Department of Physics, Virginia Tech, Blacksburg, VA 24061 (United States); and others

    2014-09-20

    We describe a search for submillimeter emission in the vicinity of one of the most distant, luminous galaxies known, HerMES FLS3, at z = 6.34, exploiting it as a signpost to a potentially biased region of the early universe, as might be expected in hierarchical structure formation models. Imaging to the confusion limit with the innovative, wide-field submillimeter bolometer camera, SCUBA-2, we are sensitive to colder and/or less luminous galaxies in the surroundings of HFLS3. We use the Millennium Simulation to illustrate that HFLS3 may be expected to have companions if it is as massive as claimed, but find no significant evidence from the surface density of SCUBA-2 galaxies in its vicinity, or their colors, that HFLS3 marks an overdensity of dusty, star-forming galaxies. We cannot rule out the presence of dusty neighbors with confidence, but deeper 450 μm imaging has the potential to more tightly constrain the redshifts of nearby galaxies, at least one of which likely lies at z ≳ 5. If associations with HFLS3 can be ruled out, this could be taken as evidence that HFLS3 is less biased than a simple extrapolation of the Millennium Simulation may imply. This could suggest either that it represents a rare short-lived, but highly luminous, phase in the evolution of an otherwise typical galaxy, or that this system has suffered amplification due to a foreground gravitational lens and so is not as intrinsically luminous as claimed.

  13. Diffusion in and around alginate and chitosan films with embedded sub-millimeter voids

    Energy Technology Data Exchange (ETDEWEB)

    Patra, Subhajit; Bal, Dharmendra Kumar; Ganguly, Somenath, E-mail: snganguly@che.iitkgp.ernet.in

    2016-02-01

    Hydrogel scaffolds from biopolymers have potential use in the controlled release of drugs, and as 3-D structure for the formation of tissue matrix. This article describes the solute release behavior of alginate and chitosan films with embedded voids of sub-millimeter dimensions. Nitrogen gas was bubbled in a fluidic arrangement to generate bubbles, prior to the crosslinking. The crosslinked gel was dried in a vacuum oven, and subsequently, soaked in Vitamin B-12 solution. The dimensions of the voids immediately after the cross-linking of gel, and also after complete drying were obtained using a digital microscope and scanning electron microscope respectively. The porosity of the gel was measured gravimetrically. The release of Vitamin B-12 in PBS buffer on a shaker was studied. The release experiments were repeated at an elevated temperature of 37 °C in the presence of lysozyme. The diffusion coefficient within the gel layer and the mass transfer coefficient at the interface with the bulk-liquid were estimated using a mathematical model. For comparison, the experiment was repeated with a film that does not have any embedded void. The enhancement in diffusion coefficient due to the presence of voids is discussed in this article. - Highlights: • Formation of sub-millimeter voids in biopolymer films using fluidic arrangement • The retention of self-assembled bubbles in films after crosslinking, and drying • The enhancement observed in release of model drug with introduction of voids • The diffusion coefficients in and around biopolymer films from model regression • Use of classical model in explaining release profiles from dual porosity media.

  14. Autonomous field measurements of CO2 in the atmospheric column with the miniaturized laser heterodyne radiometer (Mini-LHR)

    Science.gov (United States)

    Melroy, H. R.; Wilson, E. L.; Clarke, G. B.; Ott, L. E.; Mao, J.; Ramanathan, A. K.; McLinden, M. L.

    2015-09-01

    We present column CO2 measurements taken by the passive miniaturized laser heterodyne radiometer (Mini-LHR) at 1611.51 nm at the Mauna Loa Observatory in Hawaii. The Mini-LHR was operated autonomously, during the month of May 2013 at this site, working in tandem with an AERONET sun photometer that measures aerosol optical depth at 15-min intervals during daylight hours. Laser heterodyne radiometry has been used since the 1970s to measure atmospheric gases such as ozone, water vapor, methane, ammonia, chlorine monoxide, and nitrous oxide. This iteration of the technology utilizes distributed feedback lasers to produce a low-cost, small, portable sensor that has potential for global deployment. Applications of this instrument include supplementation of existing monitoring networks to provide denser global coverage, providing validation for larger satellite missions, and targeting regions of carbon flux uncertainty. Also presented here are preliminary retrieval analysis and the performance analysis that demonstrate that the Mini-LHR responds extremely well to changes in the atmospheric absorption.

  15. Real-time micro-vibration multi-spot synchronous measurement within a region based on heterodyne interference

    Science.gov (United States)

    Lan, Ma; Xiao, Wen; Chen, Zonghui; Hao, Hongliang; Pan, Feng

    2018-01-01

    Real-time micro-vibration measurement is widely used in engineering applications. It is very difficult for traditional optical detection methods to achieve real-time need in a relatively high frequency and multi-spot synchronous measurement of a region at the same time,especially at the nanoscale. Based on the method of heterodyne interference, an experimental system of real-time measurement of micro - vibration is constructed to satisfy the demand in engineering applications. The vibration response signal is measured by combing optical heterodyne interferometry and a high-speed CMOS-DVR image acquisition system. Then, by extracting and processing multiple pixels at the same time, four digital demodulation technique are implemented to simultaneously acquire the vibrating velocity of the target from the recorded sequences of images. Different kinds of demodulation algorithms are analyzed and the results show that these four demodulation algorithms are suitable for different interference signals. Both autocorrelation algorithm and cross-correlation algorithm meet the needs of real-time measurements. The autocorrelation algorithm demodulates the frequency more accurately, while the cross-correlation algorithm is more accurate in solving the amplitude.

  16. Autonomous Field Measurements of CO2 in the Atmospheric Column with the Miniaturized Laser Heterodyne Radiometer (Mini-LHR)

    Science.gov (United States)

    Melroy, H. R.; Wilson, E. L.; Clarke, G. B.; Ott, L. E.; Mao, J.; Ramanathan, A. K.; McLinden, M. L.

    2015-01-01

    We present column CO2 measurements taken by the passive Miniaturized Laser Heterodyne Radiometer (Mini-LHR) at 1611.51 nm at the Mauna Loa Observatory (MLO) in Hawaii. The Mini-LHR was operated autonomously, during the month of May 2013 at this site, working in tandem with an AERONET sun photometer that measures aerosol optical depth at 15 minute intervals during daylight hours. Laser Heterodyne Radiometry has been used since the 1970s to measure atmospheric gases such as ozone, water vapor, methane, ammonia, chlorine monoxide, and nitrous oxide. This iteration of the technology utilizes distributed feedback lasers to produce a low-cost, small, portable sensor that has potential for global deployment. Applications of this instrument include supplementation of existing monitoring networks to provide denser global coverage, providing validation for larger satellite missions, and targeting regions of carbon flux uncertainty. Also presented here is a preliminary retrieval analysis and the performance analysis that demonstrates that the Mini-LHR responds extremely well to changes in the atmospheric absorption.

  17. A heterodyne straightness and displacement measuring interferometer with laser beam drift compensation for long-travel linear stage metrology.

    Science.gov (United States)

    Chen, Benyong; Cheng, Liang; Yan, Liping; Zhang, Enzheng; Lou, Yingtian

    2017-03-01

    The laser beam drift seriously influences the accuracy of straightness or displacement measurement in laser interferometers, especially for the long travel measurement. To solve this problem, a heterodyne straightness and displacement measuring interferometer with laser beam drift compensation is proposed. In this interferometer, the simultaneous measurement of straightness error and displacement is realized by using heterodyne interferometry, and the laser beam drift is determined to compensate the measurement results of straightness error and displacement in real time. The optical configuration of the interferometer is designed. The principle of the simultaneous measurement of straightness, displacement, and laser beam drift is depicted and analyzed in detail. And the compensation of the laser beam drift for the straightness error and displacement is presented. Several experiments were performed to verify the feasibility of the interferometer and the effectiveness of the laser beam drift compensation. The experiments of laser beam stability show that the position stability of the laser beam spot can be improved by more than 50% after compensation. The measurement and compensation experiments of straightness error and displacement by testing a linear stage at different distances show that the straightness and displacement obtained from the interferometer are in agreement with those obtained from a compared interferometer and the measured stage. These demonstrate that the merits of this interferometer are not only eliminating the influence of laser beam drift on the measurement accuracy but also having the abilities of simultaneous measurement of straightness error and displacement as well as being suitable for long-travel linear stage metrology.

  18. An ALMA survey of submillimeter galaxies in the extended Chandra deep field south: The redshift distribution and evolution of submillimeter galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, J. M.; Swinbank, A. M.; Smail, Ian; Alexander, D. M.; Danielson, A. L. R.; Thomson, A. P. [Institute for Computational Cosmology, Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom); Brandt, W. N. [Department of Astronomy and Astrophysics, 525 Davey Lab, Pennsylvania State University, University Park, PA 16802 (United States); Bertoldi, F.; Karim, A. [Argelander-Institute for Astronomy, Bonn University, Auf dem Hügel 71, D-53121 Bonn (Germany); De Breuck, C. [European Southern Observatory, Karl-Schwarzschild Straße, D-85748 Garching bei München (Germany); Chapman, S. C. [Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS B3H 3J5 (Canada); Coppin, K. E. K. [Centre for Astrophysics Research, Science and Technology Research Institute, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom); Da Cunha, E.; Hodge, J. A.; Schinnerer, E. [Max-Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); Dannerbauer, H. [Universität Wien, Institut für Astrophysik, Türkenschanzstraße 17, A-1180 Wien (Austria); Greve, T. R. [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Ivison, R. J. [Institute for Astronomy, University of Edinburgh, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Knudsen, K. K. [Department of Earth and Space Science, Onsala Space Observatory, Chalmers University of Technology, SE-43992 Onsala (Sweden); Poggianti, B. M., E-mail: j.m.simpson@dur.ac.uk [INAF-Astronomical Observatory of Padova, I-35122 Padova (Italy); and others

    2014-06-20

    We present the first photometric redshift distribution for a large sample of 870 μm submillimeter galaxies (SMGs) with robust identifications based on observations with ALMA. In our analysis we consider 96 SMGs in the Extended Chandra Deep Field South, 77 of which have 4-19 band photometry. We model the SEDs for these 77 SMGs, deriving a median photometric redshift of z {sub phot} = 2.3 ± 0.1. The remaining 19 SMGs have insufficient photometry to derive photometric redshifts, but a stacking analysis of Herschel observations confirms they are not spurious. Assuming that these SMGs have an absolute H-band magnitude distribution comparable to that of a complete sample of z ∼ 1-2 SMGs, we demonstrate that they lie at slightly higher redshifts, raising the median redshift for SMGs to z {sub phot} = 2.5 ± 0.2. Critically we show that the proportion of galaxies undergoing an SMG-like phase at z ≥ 3 is at most 35% ± 5% of the total population. We derive a median stellar mass of M {sub *} = (8 ± 1) × 10{sup 10} M {sub ☉}, although there are systematic uncertainties of up to 5 × for individual sources. Assuming that the star formation activity in SMGs has a timescale of ∼100 Myr, we show that their descendants at z ∼ 0 would have a space density and M{sub H} distribution that are in good agreement with those of local ellipticals. In addition, the inferred mass-weighted ages of the local ellipticals broadly agree with the look-back times of the SMG events. Taken together, these results are consistent with a simple model that identifies SMGs as events that form most of the stars seen in the majority of luminous elliptical galaxies at the present day.

  19. Study of the optical crosstalk in a heterodyne displacement gauge with cancelable circuit

    Science.gov (United States)

    Donazzan, Alberto; Naletto, Giampiero; Pelizzo, Maria G.

    2017-06-01

    One main focus of high precision heterodyne displacement interferometers are the means of splitting and merging for the reference (R) and measurement (M) beams when a cancelable circuit is implemented. Optical mixing of R and M gives birth to a systematc error called cyclic error, which appears as a periodic offset between the detected displacement and the actual one. A simple derivation of the cyclic error due to optical mixing is proposed for the cancelable circuit design. R and M beatings are collected by two photodiodes and conveniently converted by transimpedance amplifiers, such that the output signals are turned into ac-coupled voltages. The detected phase can be calculated as a function of the real phase (a change in optical path difference) in the case of zero-crossing detection. What turns out is a cyclic non-linearity which depends on the actual phase and on the amount of optical power leakage from the R channel into the M channel and vice versa. We then applied this result to the prototype of displacement gauge we are developing, which implements the cancelable circuit design with wavefront division. The splitting between R and M is done with a double coated mirror with a central hole, tilted by 45° with respect to the surface normal. The interferometer features two removable diffraction masks, respectively located before the merging point (a circular obscuration) and before the recombination point (a ring obscuration). In order to predict the extent of optical mixing between R and M, the whole layout was simulated by means of the Zemax ® Physical Optics Propagation (POP) tool. After the model of our setup was built and qualitatively verified, we proceeded by calculating the amount of optical leakages in various configurations: with and without the diffraction masks as well as for different sizes of both the holey mirror and the diffraction masks. The corrisponding maximum displacement error was then calculated for every configuration thanks to the

  20. The Next-Generation Very Large Array: Technical Overview

    Science.gov (United States)

    McKinnon, Mark; Selina, Rob

    2018-01-01

    As part of its mandate as a national observatory, the NRAO is looking toward the long range future of radio astronomy and fostering the long term growth of the US astronomical community. NRAO has sponsored a series of science and technical community meetings to consider the science mission and design of a next-generation Very Large Array (ngVLA), building on the legacies of the Atacama Large Millimeter/submillimeter Array (ALMA) and the Very Large Array (VLA).The basic ngVLA design emerging from these discussions is an interferometric array with approximately ten times the sensitivity and ten times higher spatial resolution than the VLA and ALMA radio telescopes, optimized for operation in the wavelength range 0.3cm to 3cm. The ngVLA would open a new window on the Universe through ultra-sensitive imaging of thermal line and continuum emission down to milli-arcsecond resolution, as well as unprecedented broadband continuum polarimetric imaging of non-thermal processes. The specifications and concepts for major ngVLA system elements are rapidly converging.We will provide an overview of the current system design of the ngVLA. The concepts for major system elements such as the antenna, receiving electronics, and central signal processing will be presented. We will also describe the major development activities that are presently underway to advance the design.

  1. A novel measurement technique to estimate the RF beat-linewidth of free-running heterodyning system using a photonic discriminator

    NARCIS (Netherlands)

    Khan, M.R.H.; Marpaung, D.A.I.; Burla, M.; Roeloffzen, C.G.H.

    2011-01-01

    We propose a novel technique to our knowledge to estimate the beat spectrum linewidth of a free-running heterodyning scheme using an optical discriminator. Utilizing a dense wavelength division multiplexing (DWDM) filter as an optical discriminator, the phase modulation (PM) to intensity modulation

  2. Generation and transmission of 8 × 112-Gb/s WDM PDM-16QAM on a 25-GHz grid with simplified heterodyne detection.

    Science.gov (United States)

    Dong, Ze; Li, Xinying; Yu, Jianguo; Yu, Jianjun

    2013-01-28

    We propose and experimentally demonstrate a coherent receiver based on simplified heterodyne detection for 100 G polarization division multiplexing (PDM) signal. Compared to the conventional homodyne detection, only two balanced photo detectors (PDs) and two analog-to-digital converters (ADCs) are used in the simplified heterodyne detection. Compared to the conventional hybrid for homodyne detection, the polarization-diversity hybrid here is also simplified. The in-phase/quadrature (I/Q) separation and corresponding digital signal processing (DSP) following downconversion are realized in digital domain after ADCs. Using this scheme, we successfully demonstrated 8 × 112-Gb/s wavelength-division-multiplexing (WDM) polarization-division-multiplexing 16-ary quadrature amplitude modulation (PDM-16QAM) over 720-km single-mode fiber (SMF)-28 with heterodyne detection based on DSP and erbium-doped fiber amplifier (EDFA)-only amplification. Although the required analog bandwidth and sampling speed of the PDs and ADCs are significantly increased for heterodyne detection, the benefits from the simplified coherent receiver architecture and effective DSP in digital frequency domain are experimentally demonstrated.

  3. Integrated infrared array technology

    Science.gov (United States)

    Goebel, J. H.; Mccreight, C. R.

    1987-01-01

    An overview of integrated infrared (IR) array technology is presented. Although the array pixel formats are smaller, and the readout noise of IR arrays is larger than the corresponding values achieved with optical charge-coupled-device silicon technology, substantial progress is being made in IR technology. Both existing IR arrays and those being developed are described. Examples of astronomical images are given which illustrate the potential of integrated IR arrays for scientific investigations.

  4. The ArTéMiS wide-field sub-millimeter camera: preliminary on-sky performance at 350 microns

    Science.gov (United States)

    Revéret, Vincent; André, Philippe; Le Pennec, Jean; Talvard, Michel; Agnèse, Patrick; Arnaud, Agnès.; Clerc, Laurent; de Breuck, Carlos; Cigna, Jean-Charles; Delisle, Cyrille; Doumayrou, Eric; Duband, Lionel; Dubreuil, Didier; Dumaye, Luc; Ercolani, Eric; Gallais, Pascal; Groult, Elodie; Jourdan, Thierry; Leriche, Bernadette; Maffei, Bruno; Lortholary, Michel; Martignac, Jérôme; Rabaud, Wilfried; Relland, Johan; Rodriguez, Louis; Vandeneynde, Aurélie; Visticot, François

    2014-07-01

    ArTeMiS is a wide-field submillimeter camera operating at three wavelengths simultaneously (200, 350 and 450 μm). A preliminary version of the instrument equipped with the 350 μm focal plane, has been successfully installed and tested on APEX telescope in Chile during the 2013 and 2014 austral winters. This instrument is developed by CEA (Saclay and Grenoble, France), IAS (France) and University of Manchester (UK) in collaboration with ESO. We introduce the mechanical and optical design, as well as the cryogenics and electronics of the ArTéMiS camera. ArTeMiS detectors consist in Si:P:B bolometers arranged in 16×18 sub-arrays operating at 300 mK. These detectors are similar to the ones developed for the Herschel PACS photometer but they are adapted to the high optical load encountered at APEX site. Ultimately, ArTeMiS will contain 4 sub-arrays at 200 μm and 2×8 sub-arrays at 350 and 450 μm. We show preliminary lab measurements like the responsivity of the instrument to hot and cold loads illumination and NEP calculation. Details on the on-sky commissioning runs made in 2013 and 2014 at APEX are shown. We used planets (Mars, Saturn, Uranus) to determine the flat-field and to get the flux calibration. A pointing model was established in the first days of the runs. The average relative pointing accuracy is 3 arcsec. The beam at 350 μm has been estimated to be 8.5 arcsec, which is in good agreement with the beam of the 12 m APEX dish. Several observing modes have been tested, like "On- The-Fly" for beam-maps or large maps, spirals or raster of spirals for compact sources. With this preliminary version of ArTeMiS, we concluded that the mapping speed is already more than 5 times better than the previous 350 μm instrument at APEX. The median NEFD at 350 μm is 600 mJy.s1/2, with best values at 300 mJy.s1/2. The complete instrument with 5760 pixels and optimized settings will be installed during the first half of 2015.

  5. Far-Infrared and Submillimeter Emission from Galactic and Extragalactic Photodissociation Regions

    Science.gov (United States)

    Kaufman, Michael J.; Wolfire, Mark G.; Hollenbach, David J.; Luhman, Michael L.

    1999-12-01

    Photodissociation region (PDR) models are computed over a wide range of physical conditions, from those appropriate to giant molecular clouds illuminated by the interstellar radiation field to the conditions experienced by circumstellar disks very close to hot massive stars. These models use the most up-to-date values of atomic and molecular data, the most current chemical rate coefficients, and the newest grain photoelectric heating rates, which include treatments of small grains and large molecules. In addition, we examine the effects of metallicity and cloud extinction on the predicted line intensities. Results are presented for PDR models with densities over the range n=101-107 cm-3 and for incident far-ultraviolet radiation fields over the range G0=10-0.5-106.5 (where G0 is the far-ultravioliet [FUV] flux in units of the local interstellar value), for metallicities Z=1 and 0.1 times the local Galactic value, and for a range of PDR cloud sizes. We present line strength and/or line ratio plots for a variety of useful PDR diagnostics: [C II] 158 μm, [O I] 63 μm and 145 μm, [C I] 370 μm and 609 μm, CO J=1-0, J=2-1, J=3-2, J=6-5, and J=15-14, as well as the strength of the far-infrared continuum. These plots will be useful for the interpretation of Galactic and extragalactic far-infrared and submillimeter spectra observable with the Infrared Space Observatory (ISO), the Stratospheric Observatory for Infrared Astronomy, the Submillimeter Wave Astronomy Satellite, the Far Infrared and Submillimeter Telescope, and other orbital and suborbital platforms. As examples, we apply our results to ISO and ground-based observations of M82, NGC 278, and the Large Magellanic Cloud. Our comparison of the conditions in M82 and NGC 278 show that both the gas density and FUV flux are enhanced in the starburst nucleus of M82 compared with those in the normal spiral NGC 278. We model the high [C II]/CO ratio observed in the 30 Doradus region of the LMC and find that it can be

  6. Submillimeter residual losses in high-Tc superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Miller, David [Univ. of California, Berkeley, CA (United States)

    1993-09-01

    Bolometry was used obtain accurate submillimeter residual loss data for epitaxial films of YBa2Cu3O7 (YBCO), Tl2Ca2Ba2Cu3O10, Tl2CaBa2Cu2O8 (TCBCO), and Ba0.6K0.4BiO3 (BKBO). We were able to fit the absorptivity measured for Nb films to an Eliashberg strong coupling calculation; excellent agreement resulted between parameters from best fits and measured Residual Resistivity Ratio. Microwave surface resistance measurements made on the same YBCO and TCBCO films are in excellent agreement with submillimeter measurements. Absorptivities for all YBCO films studied are qualitatively similar, increasing smoothly with frequency, with no gap-like features below the well known absorption edge at 450 cm-1. Losses in YBCO films were fit to a weakly coupled grain model for the a-b plane conductivity. Strong phonon structure was observed in TCBCO films between 60 and 700 cm-1 (2 THz and 23 THz); these losses could not be fitted to the simple weakly coupled grain model, in contrast to the case for other high-Tc superconductors where phonon structure observed in ceramics are is absent in epitaxial oriented films and crystals because of electronic screening due to high conductivity of a-b planes. Absorptivity data for the BKBO films all show a strong absorption onset near the BCS tunneling gap of 3.5 kBTc. Comparison with strong coupling Eliashberg predictions and of a Kramers-Kronig analysis indicate that the absorption onset is consistent with a superconducting energy gap. Effects of magnetic field on residual losses in YBCO films show a resonant absorption feature in vicinity of predicted

  7. Comparing Submillimeter Polarized Emission with Near-infrared Polarization of Background Stars for the Vela C Molecular Cloud

    Science.gov (United States)

    Santos, Fabio P.; Ade, Peter A. R.; Angilè, Francesco E.; Ashton, Peter; Benton, Steven J.; Devlin, Mark J.; Dober, Bradley; Fissel, Laura M.; Fukui, Yasuo; Galitzki, Nicholas; Gandilo, Natalie N.; Klein, Jeffrey; Korotkov, Andrei L.; Li, Zhi-Yun; Martin, Peter G.; Matthews, Tristan G.; Moncelsi, Lorenzo; Nakamura, Fumitaka; Netterfield, Calvin B.; Novak, Giles; Pascale, Enzo; Poidevin, Frédérick; Savini, Giorgio; Scott, Douglas; Shariff, Jamil A.; Diego Soler, Juan; Thomas, Nicholas E.; Tucker, Carole E.; Tucker, Gregory S.; Ward-Thompson, Derek

    2017-03-01

    We present a large-scale combination of near-infrared (near-IR) interstellar polarization data from background starlight with polarized emission data at submillimeter wavelengths for the Vela C molecular cloud. The near-IR data consist of more than 6700 detections probing a range of visual extinctions between 2 and 20 {mag} in and around the cloud. The submillimeter data were collected in Antarctica by the Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry. This is the first direct combination of near-IR and submillimeter polarization data for a molecular cloud aimed at measuring the “polarization efficiency ratio” ({R}{eff}), a quantity that is expected to depend only on grain-intrinsic physical properties. It is defined as {p}500/({p}I/{τ }V), where p 500 and p I are polarization fractions at 500 μ {{m}} and the I band, respectively, and {τ }V is the optical depth. To ensure that the same column density of material is producing both polarization from emission and from extinction, we conducted a careful selection of near-background stars using 2MASS, Herschel, and Planck data. This selection excludes objects contaminated by the Galactic diffuse background material as well as objects located in the foreground. Accounting for statistical and systematic uncertainties, we estimate an average {R}{eff} value of 2.4 ± 0.8, which can be used to test the predictions of dust grain models designed for molecular clouds when such predictions become available. The ratio {R}{eff} appears to be relatively flat as a function of the cloud depth for the range of visual extinctions probed.

  8. High-throughput heterodyne thermoreflectance: Application to thermal conductivity measurements of a Fe-Si-Ge thin film alloy library

    Science.gov (United States)

    d'Acremont, Quentin; Pernot, Gilles; Rampnoux, Jean-Michel; Furlan, Andrej; Lacroix, David; Ludwig, Alfred; Dilhaire, Stefan

    2017-07-01

    A High-Throughput Time-Domain ThermoReflectance (HT-TDTR) technique was developed to perform fast thermal conductivity measurements with minimum user actions required. This new setup is based on a heterodyne picosecond thermoreflectance system. The use of two different laser oscillators has been proven to reduce the acquisition time by two orders of magnitude and avoid the experimental artefacts usually induced by moving the elements present in TDTR systems. An amplitude modulation associated to a lock-in detection scheme is included to maintain a high sensitivity to thermal properties. We demonstrate the capabilities of the HT-TDTR setup to perform high-throughput thermal analysis by mapping thermal conductivity and interface resistances of a ternary thin film silicide library FexSiyGe100-x-y (20 analysis areas of different ternary alloy compositions.

  9. Performance analysis of multihop heterodyne free-space optical communication over general Malaga turbulence channels with pointing error

    KAUST Repository

    Alheadary, Wael Ghazy

    2017-09-21

    This work investigates the end-to-end performance of a free space optical amplify-and-forward (AF) channel-state-information (CSI)-assisted relaying system using heterodyne detection over Malaga turbulence channels at the presence of pointing error employing rectangular quadrature amplitude modulation (R-QAM). More specifically, we present exact closed-form expressions for average bit-error rate for adaptive/non-adaptive modulation, achievable spectral efficiency, and ergodic capacity by utilizing generalized power series of Meijer\\'s G-function. Moreover, asymptotic closed form expressions are provided to validate our work at high power regime. In addition, all the presented analytical results are illustrated using a selected set of numerical results. Moreover, we applied the bisection method to find the optimum beam width for the proposed FSO system.

  10. Fiber Transmission Stabilization by Optical Heterodyning Techniques and Synchronization of Mode-Locked Lasers Using Two Spectral Lines

    CERN Document Server

    Staples, J W

    2005-01-01

    Stabilization of the transit time through a glass fiber using an optical heterodyne technique promises to provide jitter reduction down to the few femtosecond level using inexpensive commodity hardware. An acousto-optical frequency shifter provides the optical frequency offset that is used to downconvert phase shifts at optical frequency to equivalent phase shifts at radio frequency which are used to close a phase-lock loop driving a piezoelectric phase shifter. Using the stabilized fiber transmission medium, two spectral lines of a mode locked laser lock two low-power CW lasers which are transmitted to a receiver which phase locks the same spectral lines of a second mode-locked laser to the first. The optical transmission system operates at low power and is linear, providing excellent signal-to-noise ratio and allows many signals to be transmitted without mutual interference. Experimental results will be presented.

  11. Observation of fiber fuse propagation speed with high temporal resolution using heterodyne detection and time-frequency analysis.

    Science.gov (United States)

    Jiang, Shoulin; Ma, Lin; Fan, Xinyu; Wang, Shuai; He, Zuyuan

    2017-09-01

    We demonstrate real-time observation of fiber fuse propagation speed with high temporal resolution of 2.4 μs by combining heterodyne detection and time-frequency analysis. The periodic oscillation of fiber fuse propagation speed over a power range from 2.5 to 6.3 W with an increase in oscillation frequency from 6.18 to 6.45 kHz was observed. The relaxation processes before reaching equilibrium have been studied during initiation and power modulation processes for the first time, to the best of our knowledge. We confirm that the speed variation is largely dependent on the power fluctuation during the termination process. The proposed method is useful for validating the different fiber fuse heat conduction models.

  12. Coherent demodulation of microwave signals by using optical heterodyne technique with applications to point to point indoor wireless communications systems

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Juarez, A; Gomez-Colin, M R; Rojas-Hernandez, A G [Universidad de Sonora (Mexico); Zaldivar-Huerta, I E; Aguayo-Rodriguez, G [Instituto Nacional de Astrofisica, Optica y Electronica (Mexico); Rodriguez-Asomoza, J, E-mail: agarcia@cifus.uson.mx [Universidad de las Americas-Puebla (Mexico)

    2011-01-01

    An optical communications system using a couple microstrip antennas for distributing point to point analog TV with coherent demodulation based on optical heterodyne in close vicinity is reported in this paper. In the proposed experimental setup, two optical waves at different wavelengths are mixed and applied to a photodetector. Then a beat signal with a frequency equivalent to the spacing of the two wavelengths is obtained at the output of the photodetector. This signal corresponds to a microwave signal located at 1.25 GHz, which it is used as a microwave carrier in the transmitter and as a local oscillator in the receiver of our optical communication system. The feasibility of this technique is demonstrated transmitting a TV signal of 66-72 MHz.

  13. Study of Rydberg blockade mediated optical non-linearity in thermal vapor using optical heterodyne detection technique

    CERN Document Server

    Bhowmick, Arup; Mohapatra, Ashok K

    2016-01-01

    We demonstrate the phenomenon of blockade in two-photon excitations to the Rydberg state in thermal vapor. A technique based on optical heterodyne is used to measure the dispersion of a probe beam far off resonant to the D2 line of rubidium in the presence of a strong laser beam that couples to the Rydberg state via two-photon resonance. Density dependent suppression of the dispersion peak is observed while coupling to the Rydberg state with principal quantum number, n = 60. The experimental observation is explained using the phenomenon of Rydberg blockade. The blockade radius is measured to be about 2.2 {\\mu}m which is consistent with the scaling due to the Doppler width of 2-photon resonance in thermal vapor. Our result promises the realization of single photon source and strong single photon non-linearity based on Rydberg blockade in thermal vapor.

  14. A Comparison of Delayed Self-Heterodyne Interference Measurement of Laser Linewidth Using Mach-Zehnder and Michelson Interferometers

    Science.gov (United States)

    Canagasabey, Albert; Michie, Andrew; Canning, John; Holdsworth, John; Fleming, Simon; Wang, Hsiao-Chuan; Åslund, Mattias L.

    2011-01-01

    Linewidth measurements of a distributed feedback (DFB) fibre laser are made using delayed self heterodyne interferometry (DHSI) with both Mach-Zehnder and Michelson interferometer configurations. Voigt fitting is used to extract and compare the Lorentzian and Gaussian linewidths and associated sources of noise. The respective measurements are wL (MZI) = (1.6 ± 0.2) kHz and wL (MI) = (1.4 ± 0.1) kHz. The Michelson with Faraday rotator mirrors gives a slightly narrower linewidth with significantly reduced error. This is explained by the unscrambling of polarisation drift using the Faraday rotator mirrors, confirmed by comparing with non-rotating standard gold coated fibre end mirrors. PMID:22163692

  15. Turbulence heterodyne coherent mitigation of orbital angular momentum multiplexing in a free space optical link by auxiliary light.

    Science.gov (United States)

    Yang, Chunyong; Xu, Chuang; Ni, Wenjun; Gan, Yu; Hou, Jin; Chen, Shaoping

    2017-10-16

    A novel scheme is proposed to mitigate the atmospheric turbulence effect in free space optical (FSO) communication employing orbital angular momentum (OAM) multiplexing. In this scheme, the Gaussian beam is used as an auxiliary light with a common-path to obtain the distortion information caused by atmospheric turbulence. After turbulence, the heterodyne coherent detection technology is demonstrated to realize the turbulence mitigation. With the same turbulence distortion, the OAM beams and the Gaussian beam are respectively utilized as the signal light and the local oscillation light. Then the turbulence distortion is counteracted to a large extent. Meanwhile, a phase matching method is proposed to select the specific OAM mode. The discrimination between the neighboring OAM modes is obviously improved by detecting the output photocurrent. Moreover, two methods of beam size adjustment have been analyzed to achieve better performance for turbulence mitigation. Numerical results show that the system bit error rate (BER) can reach 10-5 under strong turbulence in simulation situation.

  16. Design and characterization of a 32-channel heterodyne radiometer for electron cyclotron emission measurements on experimental advanced superconducting tokamak.

    Science.gov (United States)

    Han, X; Liu, X; Liu, Y; Domier, C W; Luhmann, N C; Li, E Z; Hu, L Q; Gao, X

    2014-07-01

    A 32-channel heterodyne radiometer has been developed for the measurement of electron cyclotron emission (ECE) on the experimental advanced superconducting tokamak (EAST). This system collects X-mode ECE radiation spanning a frequency range of 104-168 GHz, where the frequency coverage corresponds to a full radial coverage for the case with a toroidal magnetic field of 2.3 T. The frequency range is equally spaced every 2 GHz from 105.1 to 167.1 GHz with an RF bandwidth of ~500 MHz and the video bandwidth can be switched among 50, 100, 200, and 400 kHz. Design objectives and characterization of the system are presented in this paper. Preliminary results for plasma operation are also presented.

  17. Two color multichannel heterodyne interferometer set up for high spatial resolution electron density profile measurements in TJ-II

    Energy Technology Data Exchange (ETDEWEB)

    Pedreira, P.; Criado, A. R.; Acedo, P. [Department of Electronics Technology, Universidad Carlos III de Madrid, Leganes, Madrid 28911 (Spain); Esteban, L.; Sanchez, M.; Sanchez, J. [Laboratorio Nacional de Fusion por ConfinamientoMagnetico-CIEMAT, Madrid 28040 (Spain)

    2010-10-15

    A high spatial resolution two color [CO{sub 2}, {lambda}=10.6 {mu}m/Nd:YAG (Nd:YAG denotes neodymium-doped yttrium aluminum garnet), and {lambda}=1.064 {mu}m] expanded-beam multichannel heterodyne interferometer has been installed on the TJ-II stellarator. Careful design of the optical system has allowed complete control on the evolution of both Gaussian beams along the interferometer, as well as the evaluation and optimization of the spatial resolution to be expected in the measurements. Five CO{sub 2} (measurement) channels and three Nd:YAG (vibration compensation) channels have been used to illuminate the plasma with a probe beam of 100 mm size. An optimum interpolation method has been applied to recover both interferometric phasefronts prior to mechanical vibration subtraction. The first results of the installed diagnostic are presented in this paper.

  18. Space-borne remote sensing of CO2 by IPDA lidar with heterodyne detection: random error estimation

    Science.gov (United States)

    Matvienko, G. G.; Sukhanov, A. Y.

    2015-11-01

    Possibilities of measuring the CO2 column concentration by spaceborne integrated path differential lidar (IPDA) signals in the near IR absorption bands are investigated. It is shown that coherent detection principles applied in the nearinfrared spectral region promise a high sensitivity for the measurement of the integrated dry air column mixing ratio of the CO2. The simulations indicate that for CO2 the target observational requirements (0.2%) for the relative random error can be met with telescope aperture 0.5 m, detector bandwidth 10 MHz, laser energy per impulse 0.3 mJ and averaging 7500 impulses. It should also be noted that heterodyne technique allows to significantly reduce laser power and receiver overall dimensions compared to direct detection.

  19. Frequency stabilization of a 1083 nm fiber laser to ⁴He transition lines with optical heterodyne saturation spectroscopies.

    Science.gov (United States)

    Gong, W; Peng, X; Li, W; Guo, H

    2014-07-01

    Two kinds of optical heterodyne saturation spectroscopies, namely, frequency modulation spectroscopy (FMS) and modulation transfer spectroscopy (MTS), are demonstrated for locking a fiber laser to the transition lines of metastable (4)He atoms around 1083 nm. The servo-loop error signals of FMS and MTS for stabilizing laser frequency are optimized by studying the dependence of the peak-to-peak amplitude and slope on the optical power of pump and probe beams. A comparison of the stabilization performances of FMS/MTS and polarization spectroscopy (PS) is presented, which shows that MTS exhibits relatively superior performance with the least laser frequency fluctuation due to its flat-background dispersive signal, originated from the four-wave mixing process. The Allan deviation of the stabilized laser frequency is 5.4 × 10(-12)@100 s with MTS for data acquired in 1000 s, which is sufficiently applicable for fields like laser cooling, optical pumping, and optical magnetometry.

  20. Frequency stabilization of a 1083 nm fiber laser to {sup 4}He transition lines with optical heterodyne saturation spectroscopies

    Energy Technology Data Exchange (ETDEWEB)

    Gong, W.; Peng, X., E-mail: xiangpeng@pku.edu.cn; Li, W.; Guo, H., E-mail: hongguo@pku.edu.cn [State Key Laboratory of Advanced Optical Communication Systems and Networks, School of Electronics Engineering and Computer Science, Center for Quantum Information Technology, and Center for Computational Science and Engineering (CCSE), Peking University, Beijing 100871 (China)

    2014-07-15

    Two kinds of optical heterodyne saturation spectroscopies, namely, frequency modulation spectroscopy (FMS) and modulation transfer spectroscopy (MTS), are demonstrated for locking a fiber laser to the transition lines of metastable {sup 4}He atoms around 1083 nm. The servo-loop error signals of FMS and MTS for stabilizing laser frequency are optimized by studying the dependence of the peak-to-peak amplitude and slope on the optical power of pump and probe beams. A comparison of the stabilization performances of FMS/MTS and polarization spectroscopy (PS) is presented, which shows that MTS exhibits relatively superior performance with the least laser frequency fluctuation due to its flat-background dispersive signal, originated from the four-wave mixing process. The Allan deviation of the stabilized laser frequency is 5.4 × 10{sup −12}@100 s with MTS for data acquired in 1000 s, which is sufficiently applicable for fields like laser cooling, optical pumping, and optical magnetometry.

  1. Frequency stabilization of a 1083 nm fiber laser to 4He transition lines with optical heterodyne saturation spectroscopies

    Science.gov (United States)

    Gong, W.; Peng, X.; Li, W.; Guo, H.

    2014-07-01

    Two kinds of optical heterodyne saturation spectroscopies, namely, frequency modulation spectroscopy (FMS) and modulation transfer spectroscopy (MTS), are demonstrated for locking a fiber laser to the transition lines of metastable 4He atoms around 1083 nm. The servo-loop error signals of FMS and MTS for stabilizing laser frequency are optimized by studying the dependence of the peak-to-peak amplitude and slope on the optical power of pump and probe beams. A comparison of the stabilization performances of FMS/MTS and polarization spectroscopy (PS) is presented, which shows that MTS exhibits relatively superior performance with the least laser frequency fluctuation due to its flat-background dispersive signal, originated from the four-wave mixing process. The Allan deviation of the stabilized laser frequency is 5.4 × 10-12@100 s with MTS for data acquired in 1000 s, which is sufficiently applicable for fields like laser cooling, optical pumping, and optical magnetometry.

  2. A Comparison of Delayed Self-Heterodyne Interference Measurement of Laser Linewidth Using Mach-Zehnder and Michelson Interferometers

    Directory of Open Access Journals (Sweden)

    Simon Fleming

    2011-09-01

    Full Text Available Linewidth measurements of a distributed feedback (DFB fibre laser are made using delayed self heterodyne interferometry (DHSI with both Mach-Zehnder and Michelson interferometer configurations. Voigt fitting is used to extract and compare the Lorentzian and Gaussian linewidths and associated sources of noise. The respective measurements are wL (MZI = (1.6 ± 0.2 kHz and wL (MI = (1.4 ± 0.1 kHz. The Michelson with Faraday rotator mirrors gives a slightly narrower linewidth with significantly reduced error. This is explained by the unscrambling of polarisation drift using the Faraday rotator mirrors, confirmed by comparing with non-rotating standard gold coated fibre end mirrors.

  3. The Hawaii SCUBA-2 Lensing Cluster Survey: Radio-detected Submillimeter Galaxies in the HST Frontier Fields

    Science.gov (United States)

    Hsu, Li-Yen; Desai, Vandana; Murphy, Eric J.; Cowie, Lennox L.; Heywood, Ian; Momjian, Emmanuel; Barger, Amy J.; Smail, Ian

    2017-05-01

    In this second paper of the Hawaii SCUBA-2 Lensing Cluster Survey series, we cross-match SCUBA-2 maps with 3 and 6 GHz images from the Janksy-VLA Frontier Fields Legacy Survey for three cluster fields, MACS J0416.1-2403, MACS J0717.5+3745, and MACS J1149.5+2223. Within the HST coverage, 14 out of 44 850 μm sources have 3 GHz counterparts, five of which are also detected at 6 GHz. The 850 μm flux densities of these detected sources span from 0.7 to 4.4 mJy after correcting for lensing amplification. The median redshift of the sample is z={1.28}-0.09+0.07, much lower than the typical redshifts (z = 2-3) of brighter submillimeter galaxies (SMGs) in the literature. In addition, we find that our sources have lower dust temperatures than those of the brighter SMGs. This is also confirmed by an analysis of the ratio between infrared star-formation rate and 850 μm flux density. However, these 14 sources may not represent the general submillimeter population at the same flux range, given that the SCUBA-2 sources without radio counterparts are likely at higher redshifts. Detection of these sources would require deeper radio images or submillimeter interferometry.

  4. Submillimeter Detection of the van der Waals Stretching Vibration of the Ar-CO Complex

    Science.gov (United States)

    Gendriesch, R.; Pak, I.; Lewen, F.; Surin, L.; Roth, D. A.; Winnewisser, G.

    1999-07-01

    With the Cologne submillimeter-wave supersonic jet spectrometer, we extended molecular jet spectroscopy with backward wave oscillators up to frequencies of about 600 GHz. For the first time, the van der Waals stretching vibration of the Ar-CO molecular complex was detected in direct absorption. We measured 13 ro-vibrational transitions (Kvstretch = 1 ← 0, Ka = 0 ← 0) in the frequency range from 528 to 600 GHz and additionally the two R(3) K doublet (Ka = 4 ← 3) pure rotational transitions at 447 GHz with an accuracy of about 200 kHz. The ro-vibrational transitions were assigned and fitted within experimental accuracy to a simple Hamiltonian taking into account the Coriolis interaction between the stretching and bending states, i.e., between vstretch = 1, Ka = 0, and vbend = 1, Ka = 1. The intensity of the transitions in the van der Waals stretching mode was estimated to be a factor of 5-10 less than that in the bending mode of Ar-CO.

  5. Micro-Spec: An Ultracompact, High-sensitivity Spectrometer for Far-Infrared and Submillimeter Astronomy

    Science.gov (United States)

    Cataldo, Giuseppe; Hsieh, Wen-Ting; Huang, Wei-Chung; Moseley, S. Harvey; Stevenson, Thomas R.; Wollack, Edward J.

    2014-01-01

    High-performance, integrated spectrometers operating in the far-infrared and submillimeter ranges promise to be powerful tools for the exploration of the epochs of reionization and initial galaxy formation. These devices, using high-efficiency superconducting transmission lines, can achieve the performance of a meter-scale grating spectrometer in an instrument implemented on a 4 inch silicon wafer. Such a device, when combined with a cryogenic telescope in space, provides an enabling capability for studies of the early universe. Here, the optical design process for Micro-Spec (micron-Spec) is presented, with particular attention given to its two-dimensional diffractive region, where the light of different wavelengths is focused on the different detectors. The method is based on the stigmatization and minimization of the light path function in this bounded region, which results in an optimized geometrical configuration. A point design with an efficiency of (is) approximately 90% has been developed for initial demonstration and can serve as the basis for future instruments. Design variations on this implementation are also discussed, which can lead to lower efficiencies due to diffractive losses in the multimode region.

  6. T-shaped emitter metal heterojunction bipolar transistors for submillimeter wave applications

    Science.gov (United States)

    Fung, Andy; Samoska, Lorene; Velebir, Jim; Siege, Peter; Rodwell, Mark; Paidi, Vamsi; Griffth, Zach; Urteaga, Miguel; Malik, Roger

    2004-01-01

    We report on the development of submillimeter wave transistors at JPL. The goal of the effort is to produce advance-reliable high frequency and high power amplifiers, voltage controlled oscillators, active multipliers, and high-speed mixed-signal circuits for space borne applications. The technology in development to achieve this is based on the Indium Phosphide (InP) Heterojunction Bipolar Transistor (HBT). The HBT is well suited for high speed, high power and uniform (across wafer) performance, due to the ability to tailor the material structure that electrons traverse through by well-controlled epitaxial growth methods. InP with its compatible lattice matched alloys such as indium gallium arsenide (InGaAs) and indium aluminium arsenide (InAlAs) provides for high electron velocities and high voltage breakdown capabilities. The epitaxial methods for this material system are fairly mature, however the implementation of high performance and reliable transistors are still under development by many laboratories. Our most recently fabricated, second generation mesa HBTs at JPL have extrapolated current gain cutoff frequency (FJ of 142GHz and power gain cutoff frequency (Fm,) of approximately 160GHz. This represents a 13% and 33% improvement of Ft and F, respectively, compared to the first generation mesa HBTs [l]. Analysis based on the University of California, Santa Barbara (UCSB) device model, RF device characteristics can be significantly improved by reducing base contact resistance and base metal contact width. We will describe our effort towards increasing transistor performance and yield.

  7. Controlled production of sub-millimeter liquid core hydrogel capsules for parallelized 3D cell culture.

    Science.gov (United States)

    Doméjean, Hugo; de la Motte Saint Pierre, Mathieu; Funfak, Anette; Atrux-Tallau, Nicolas; Alessandri, Kevin; Nassoy, Pierre; Bibette, Jérôme; Bremond, Nicolas

    2016-12-20

    Liquid core capsules having a hydrogel membrane are becoming a versatile tool for three-dimensional culture of micro-organisms and mammalian cells. Making sub-millimeter capsules at a high rate, via the breakup of a compound jet in air, opens the way to high-throughput screening applications. However, control of the capsule size monodispersity, especially required for quantitative bioassays, was still lacking. Here, we report how the understanding of the underlying hydrodynamic instabilities that occur during the process can lead to calibrated core-shell bioreactors. The requirements are: i) damping the shear layer instability that develops inside the injector arising from the co-annular flow configuration of liquid phases having contrasting viscoelastic properties; ii) controlling the capillary instability of the compound jet by superposing a harmonic perturbation onto the shell flow; iii) avoiding coalescence of drops during jet fragmentation as well as during drop flight towards the gelling bath; iv) ensuring proper engulfment of the compound drops into the gelling bath for building a closed hydrogel shell. We end up with the creation of numerous identical compartments in which cells are able to form multicellular aggregates, namely spheroids. In addition, we implement an intermediate composite hydrogel layer, composed of alginate and collagen, allowing cell adhesion and thus the formation of epithelia or monolayers of cells.

  8. Simultaneous retrievals of temperature and volume mixing ratio constituents from nonoxygen odin submillimeter radiometer bands.

    Science.gov (United States)

    Baron, P; Merino, F; Murtagh, D

    2001-11-20

    We present the retrieval of temperature and O(3) volume mixing ratio profiles in the middle atmosphere from a single strong O(3) line. We performed the study using simulated limb-sounding measurements in the frame of the submillimeter radiometer (SMR) instrument that will be carried by the Odin satellite that is due to be launched in early 2001. This study is interesting for the Odin SMR data analysis because we first provide additional temperature measurements, and second reduce significantly the O(3) retrieval error that is due to the temperature and pressure uncertainties. Nonlinear retrievals are performed to retrieve the O(3), CO, H(2)O, and temperature profiles simultaneously from the spectral band 576.27-576.67 GHz. The pressure profile is deduced from the hydrostatic equilibrium equation after each iteration. Temperature and O(3) can be retrieved throughout the stratosphere from 15-50 and 20-50 km, respectively, with a vertical resolution of 3 km. The altitude domain corresponds to the parts of the atmosphere where the signal intensity saturates in some spectrometer channels. A total error of 4-6 K has been found in the temperature profile, mainly because of the instrumental thermal noise and to a lesser extent the calibration. The total error in the O(3) profile is 5-10% and is dominated by the O(3) line-broadening parameter. The total error on the retrieved pressure profile is 2-10% because of the errors in calibration and reference pressure.

  9. Laboratory and observational studies of transient molecules at microwave and millimeter/submillimeter wavelengths

    Science.gov (United States)

    Zack, Lindsay Nicole

    In this dissertation, techniques of high-resolution rotational spectroscopy have been used to measure the spectra of molecules in both laboratory and astronomical settings. In the laboratory, small metal-bearing molecules containing zinc, iron, nickel, titanium, yttrium, and scandium have been studied at microwave and millimeter/submillimeter wavelengths in order to determine their rotational, fine, and hyperfine constants. These molecules were synthesized in situ in direct-absorption and Fourier-transform microwave spectrometers using Broida-type ovens and laser ablation methods. From the spectroscopic parameters, information about fundamental physical properties and electronic character could be obtained. Radio telescopes were used to measure the spectra of molecules in different interstellar environments. A new molecule, FeCN, was detected toward the circumstellar envelope of the carbon-rich asymtotic giant branch star, IRC+10216, marking the first iron-bearing molecule detected in the interstellar medium. The telescopes were also used to conduct a study of the evolved planetary nebula, NGC 7293, or the Helix Nebula. In the Helix, CO, HCO+, and H2CO were observed at several positions offset from the central star to obtain densities and kinetic temperatures throughout the Helix. A map of the HCO+ J = 1→ 0 transition was also constructed, showing that HCO+ is widespread throughout the Helix, instead of being photodissociated and destroyed, as theoretical models of planetary nebulae predict.

  10. Submillimeter Measurements of Photolysis Products in Interstellar Ice Analogs: A New Experimental Technique

    Science.gov (United States)

    Milam, Stefanie N.; Weaver, Susanna Widicus

    2012-01-01

    Over 150 molecular species have been confirmed in space, primarily by their rotational spectra at millimeter/submillimeter wavelengths, which yield an unambiguous identification. Many of the known interstellar organic molecules cannot be explained by gas-phase chemistry. It is now presumed that they are produced by surface reactions of the simple ices and/or grains observed and released into the gas phase by sublimation, sputtering, etc. Additionally, the chemical complexity found in meteorites and samples returned from comets far surpasses that of the remote detections for the interstellar medium (ISM), comets, and planetary atmospheres. Laboratory simulations of interstellar/cometary ices have found, from the analysis of the remnant residue of the warmed laboratory sample, that such molecules are readily formed; however, it has yet to be determined if they are formed during the warm phase or within the ice during processing. Most analysis of the ice during processing reveals molecular changes, though the exact quantities and species formed are highly uncertain with current techniques due to overwhelming features of simple ices. Remote sensing with high resolution spectroscopy is currently the only method to detect trace species in the ISM and the primary method for comets and icy bodies in the Solar System due to limitations of sample return. We have recently designed an experiment to simulate interstellar/cometary/planetary ices and detect trace species employing the same techniques used for remote observations. Preliminary results will be presented.

  11. Probing Galaxy Formation and Evolution with Space Born Sub-Millimeter Telescopes

    Science.gov (United States)

    Dwek, Eli; Arendt, Richard G.; Moseley, Harvey; Benford, Dominic; Shafer, Richard; Mather, John; Oegerle, William (Technical Monitor)

    2002-01-01

    A major unresolved question in cosmology is how the complex system of galaxies we see in the present universe evolved from an almost perfectly smooth beginning. Multiwavelength observations of galaxies have revealed that a significant fraction of their UV-visible starlight is absorbed and reradiated by dust at infrared JR) and submillimeter wavelengths. The cumulative IR-submm. emission from galaxies since the epoch of recombination, the cosmic IR background, has recently been recorded by the COBE satellite. The COBE observations in combination with recent submm surveys conducted with the SCUBA on the 15 m JCMT have shown that most of the radiation from star formation that has taken place in the early stages of galaxy evolution is reradiated by dust at submm wavelengths. Therefore, submm telescopes offer a unique probe of the early stages of galaxy formation and evolution. This talk will: (1) consider the impact of telescope diameter on the depth of the survey (what redshift can be probed) at different wavelengths; (2) discuss the relative scientific merits of high-resolution narrow-field surveys versus lower resolution deep surveys; and (3) show how both strategies offer complementary information crucial to our understanding of the structure and evolution of galaxies in the universe.

  12. Optical fiber sensors-based temperature distribution measurement in ex vivo radiofrequency ablation with submillimeter resolution

    Science.gov (United States)

    Macchi, Edoardo Gino; Tosi, Daniele; Braschi, Giovanni; Gallati, Mario; Cigada, Alfredo; Busca, Giorgio; Lewis, Elfed

    2014-11-01

    Radiofrequency thermal ablation (RFTA) induces a high-temperature field in a biological tissue having steep spatial (up to 6°C/mm) and temporal (up to 1°C/s) gradients. Applied in cancer care, RFTA produces a localized heating, cytotoxic for tumor cells, and is able to treat tumors with sizes up to 3 to 5 cm in diameter. The online measurement of temperature distribution at the RFTA point of care has been previously carried out with miniature thermocouples and optical fiber sensors, which exhibit problems of size, alteration of RFTA pattern, hysteresis, and sensor density worse than 1 sensor/cm. In this work, we apply a distributed temperature sensor (DTS) with a submillimeter spatial resolution for the monitoring of RFTA in porcine liver tissue. The DTS demodulates the chaotic Rayleigh backscattering pattern with an interferometric setup to obtain the real-time temperature distribution. A measurement chamber has been set up with the fiber crossing the tissue along different diameters. Several experiments have been carried out measuring the space-time evolution of temperature during RFTA. The present work showcases the temperature monitoring in RFTA with an unprecedented spatial resolution and is exportable to in vivo measurement; the acquired data can be particularly useful for the validation of RFTA computational models.

  13. A New Era of Submillimeter GRB Afterglow Follow-Ups with the Greenland Telescope

    Directory of Open Access Journals (Sweden)

    Yuji Urata

    2015-01-01

    Full Text Available Planned rapid submillimeter (submm gamma-ray-bursts (GRBs follow-up observations conducted using the Greenland Telescope (GLT are presented. The GLT is a 12-m submm telescope to be located at the top of the Greenland ice sheet, where the high altitude and dry weather porvide excellent conditions for observations at submm wavelengths. With its combination of wavelength window and rapid responding system, the GLT will explore new insights on GRBs. Summarizing the current achievements of submm GRB follow-ups, we identify the following three scientific goals regarding GRBs: (1 systematic detection of bright submm emissions originating from reverse shock (RS in the early afterglow phase, (2 characterization of forward shock and RS emissions by capturing their peak flux and frequencies and performing continuous monitoring, and (3 detections of GRBs at a high redshift as a result of the explosion of first generation stars through systematic rapid follow-ups. The light curves and spectra calculated by available theoretical models clearly show that the GLT could play a crucial role in these studies.

  14. Demonstration of a phase-lockable microwave to submillimeter wave sweeper

    Science.gov (United States)

    Waltman, Steve B.; Hollberg, Leo W.; McIntosh, Alexander K.; Brown, Elliott R.

    1996-12-01

    The development of low-temperature-grown GaAs photomixers enables the construction of a microwave to submillimeter- wave source capable of large frequency sweeps. By utilizing semiconductor diode lasers to drive the photomixer, this source is all solid-state and compact, and has small power consumption. Frequency stabilization of the semiconductor diode lasers allows this source to be phase-locked to an external microwave reference. Two 805 nm extended-cavity- diode lasers are mixed in a low-temperature-grown GaAs photoconductive photomixer. The difference-frequency mixing product is radiated by a planar spiral antenna and collimated by a Si lens. This output is phase-locked to a microwave reference by downconverting it in a whisker- contacted Schottky-barrier diode harmonic mixer and using the output to offset-phase-lock one laser to the other. The photomixer output power is 300 nW at 200 GHz and 10 nW at 1.6 THz, as measured by a 4 K InSb bolometer calibrated with a methanol laser and a power meter at 526 and 812 GHz.

  15. Rapid Asymmetric Inflation and Early Cosmology in Theories with Sub-Millimeter Dimensions

    CERN Document Server

    Arkani-Hamed, N; Kaloper, Nemanja; March-Russell, John David; Arkani-Hamed, Nima; Dimopoulos, Savas; Kaloper, Nemanja; March-Russell, John

    2000-01-01

    It was recently pointed out that the fundamental Planck mass could be close to the TeV scale with the observed weakness of gravity at long distances being due the existence of new sub-millimeter spatial dimensions. In this picture the standard model fields are localized to a $(3+1)$-dimensional wall or ``3-brane''. We show that in such theories there exist attractive models of inflation that occur while the size of the new dimensions are still small. We show that it is easy to produce the required number of efoldings, and further that the density perturbations $\\delta\\rho/\\rho$ as measured by COBE can be easily reproduced, both in overall magnitude and in their approximately scale-invariant spectrum. In the minimal approach, the inflaton field is just the moduli describing the size of the internal dimensions, the role of the inflationary potential being played by the stabilizing potential of the internal space. We show that under quite general conditions, the inflationary era is followed by an epoch of contra...

  16. DETECTION OF AN ULTRA-BRIGHT SUBMILLIMETER GALAXY BEHIND THE SMALL MAGELLANIC CLOUD

    Energy Technology Data Exchange (ETDEWEB)

    Takekoshi, Tatsuya; Minamidani, Tetsuhiro; Sorai, Kazuo; Habe, Asao [Department of Cosmosciences, Graduate School of Science, Hokkaido University, Sapporo 060-0810 (Japan); Tamura, Yoichi; Kohno, Kotaro [Institute of Astronomy, University of Tokyo, Osawa, Mitaka, Tokyo 181-0015 (Japan); Oogi, Taira [Department of Physics, Faculty of Science, Hokkaido University, Sapporo 060-0810 (Japan); Ezawa, Hajime; Komugi, Shinya; Mizuno, Norikazu; Muller, Erik; Kawamura, Akiko [Chile Observatory, National Astronomical Observatory, Mitaka, Tokyo 181-8588 (Japan); Oshima, Tai [Nobeyama Radio Observatory, National Astronomical Observatory of Japan, Minamimaki, Minamisaku, Nagano 384-1305 (Japan); Scott, Kimberly S. [North American ALMA Science Center, National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States); Austermann, Jason E. [Center for Astrophysics and Space Astronomy, University of Colorado, Boulder, CO 80309 (United States); Tosaki, Tomoka [Joetsu University of Education, Joetsu, Niigata 943-8512 (Japan); Onishi, Toshikazu [Department of Physical Science, Osaka Prefecture University, Gakuen 1-1, Sakai, 599-8531 Osaka (Japan); Fukui, Yasuo [Department of Astrophysics, Nagoya University, Chikusa-ku, Nagoya 464-8602 (Japan); Matsuo, Hiroshi [Advanced Technology Center, National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan); Aretxaga, Itziar [Instituto Nacional de Astrofisica, Optica y Electronica (INAOE), 72000 Puebla (Mexico); and others

    2013-09-10

    We report the discovery of a new ultra-bright submillimeter galaxy (SMG) behind the Small Magellanic Cloud (SMC). This SMG is detected as a 43.3 {+-} 8.4 mJy point source (MM J01071-7302, hereafter MMJ0107) in the 1.1 mm continuum survey of the SMC by AzTEC on the ASTE telescope. MMJ0107 is also detected in the radio (843 MHz), Herschel/SPIRE, Spitzer MIPS 24 {mu}m, all IRAC bands, Wide-field Infrared Survey Explorer, and near-infrared (J, H, K{sub S} ). We find an optical (U, B, V) source, which might be the lensing object, at a distance of 1.''4 from near-infrared and IRAC sources. Photometric redshift estimates for the SMG using representative spectral energy distribution templates show the redshifts of 1.4-3.9. We estimate total far-infrared luminosity of (0.3-2.2) Multiplication-Sign 10{sup 14} {mu}{sup -1} L{sub Sun} and a star formation rate of 5600-39, 000 {mu}{sup -1} M{sub Sun} yr{sup -1}, where {mu} is the gravitational magnification factor. This apparent extreme star formation activity is likely explained by a highly magnified gravitational lens system.

  17. Axiom turkey genotyping array

    Science.gov (United States)

    The Axiom®Turkey Genotyping Array interrogates 643,845 probesets on the array, covering 643,845 SNPs. The array development was led by Dr. Julie Long of the USDA-ARS Beltsville Agricultural Research Center under a public-private partnership with Hendrix Genetics, Aviagen, and Affymetrix. The Turk...

  18. Clocked combustor can array

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Won-Wook; McMahan, Kevin Weston; Srinivasan, Shiva Kumar

    2017-01-17

    The present application provides a clocked combustor can array for coherence reduction in a gas turbine engine. The clocked combustor can array may include a number of combustor cans positioned in a circumferential array. A first set of the combustor cans may have a first orientation and a second set of the combustor cans may have a second orientation.

  19. Thermophotovoltaic Array Optimization

    Energy Technology Data Exchange (ETDEWEB)

    SBurger; E Brown; K Rahner; L Danielson; J Openlander; J Vell; D Siganporia

    2004-07-29

    A systematic approach to thermophotovoltaic (TPV) array design and fabrication was used to optimize the performance of a 192-cell TPV array. The systematic approach began with cell selection criteria that ranked cells and then matched cell characteristics to maximize power output. Following cell selection, optimization continued with an array packaging design and fabrication techniques that introduced negligible electrical interconnect resistance and minimal parasitic losses while maintaining original cell electrical performance. This paper describes the cell selection and packaging aspects of array optimization as applied to fabrication of a 192-cell array.

  20. Calibration of a high spatial resolution laser two-color heterodyne interferometer for density profile measurements in the TJ-II stellarator.

    Science.gov (United States)

    Acedo, Pablo; Pedreira, P; Criado, A R; Lamela, Horacio; Sánchez, Miguel; Sánchez, Joaquín

    2008-10-01

    A high spatial resolution two-color (CO(2), lambda=10.6 microm, He-Ne, lambda=633 nm) interferometer for density profile measurements in the TJ-II stellarator is under development and installation, based in the currently operational single channel two-color heterodyne interferometer. To achieve the objectives of 32 channels, with 4-5 mm lateral separation between plasma chords, careful design and calibration of the interferometric waveforms for both the measurement and vibration compensation wavelengths are undertaken. The first step has been to set up in our laboratories an expanded-beam heterodyne/homodyne interferometer to evaluate the quality of both interferometric wavefronts, a reported source of poor vibration compensation and thus low resolution in the density profile measurements. This novel interferometric setup has allowed us to calibrate the spatial resolution in the profile measurements resulting in approximately 2 mm lateral resolution in the reconstruction of the interferometric wavefront.

  1. An ALMA Survey of Submillimeter Galaxies in the Extended Chandra Deep Field South: Spectroscopic Redshifts

    Science.gov (United States)

    Danielson, A. L. R.; Swinbank, A. M.; Smail, Ian; Simpson, J. M.; Casey, C. M.; Chapman, S. C.; da Cunha, E.; Hodge, J. A.; Walter, F.; Wardlow, J. L.; Alexander, D. M.; Brandt, W. N.; de Breuck, C.; Coppin, K. E. K.; Dannerbauer, H.; Dickinson, M.; Edge, A. C.; Gawiser, E.; Ivison, R. J.; Karim, A.; Kovacs, A.; Lutz, D.; Menten, K.; Schinnerer, E.; Weiß, A.; van der Werf, P.

    2017-05-01

    We present spectroscopic redshifts of {\\text{}}{S}870μ {{m}} ≳ 2 mJy submillimeter galaxies (SMGs), which have been identified from the ALMA follow-up observations of 870 μm detected sources in the Extended Chandra Deep Field South (the ALMA-LESS survey). We derive spectroscopic redshifts for 52 SMGs, with a median of z = 2.4 ± 0.1. However, the distribution features a high-redshift tail, with ˜23% of the SMGs at z≥slant 3. Spectral diagnostics suggest that the SMGs are young starbursts, and the velocity offsets between the nebular emission and UV ISM absorption lines suggest that many are driving winds, with velocity offsets of up to 2000 km s-1. Using the spectroscopic redshifts and the extensive UV-to-radio photometry in this field, we produce optimized spectral energy distributions (SEDs) using Magphys, and use the SEDs to infer a median stellar mass of {M}\\star = (6 ± 1)× 1010 M {}⊙ for our SMGs with spectroscopic redshift. By combining these stellar masses with the star formation rates (measured from the far-infrared SEDs), we show that SMGs (on average) lie a factor of ˜5 above the so-called “main sequence” at z˜ 2. We provide this library of 52 template fits with robust and uniquely well-sampled SEDs as a resource for future studies of SMGs, and also release the spectroscopic catalog of ˜2000 (mostly infrared-selected) galaxies targeted as part of the spectroscopic campaign.

  2. A retrieval algorithm of hydrometer profile for submillimeter-wave radiometer

    Science.gov (United States)

    Liu, Yuli; Buehler, Stefan; Liu, Heguang

    2017-04-01

    Vertical profiles of particle microphysics perform vital functions for the estimation of climatic feedback. This paper proposes a new algorithm to retrieve the profile of the parameters of the hydrometeor(i.e., ice, snow, rain, liquid cloud, graupel) based on passive submillimeter-wave measurements. These parameters include water content and particle size. The first part of the algorithm builds the database and retrieves the integrated quantities. Database is built up by Atmospheric Radiative Transfer Simulator(ARTS), which uses atmosphere data to simulate the corresponding brightness temperature. Neural network, trained by the precalculated database, is developed to retrieve the water path for each type of particles. The second part of the algorithm analyses the statistical relationship between water path and vertical parameters profiles. Based on the strong dependence existing between vertical layers in the profiles, Principal Component Analysis(PCA) technique is applied. The third part of the algorithm uses the forward model explicitly to retrieve the hydrometeor profiles. Cost function is calculated in each iteration, and Differential Evolution(DE) algorithm is used to adjust the parameter values during the evolutionary process. The performance of this algorithm is planning to be verified for both simulation database and measurement data, by retrieving profiles in comparison with the initial one. Results show that this algorithm has the ability to retrieve the hydrometeor profiles efficiently. The combination of ARTS and optimization algorithm can get much better results than the commonly used database approach. Meanwhile, the concept that ARTS can be used explicitly in the retrieval process shows great potential in providing solution to other retrieval problems.

  3. A submillimeter galaxy illuminating its circumgalactic medium: Lyα scattering in a cold, clumpy outflow

    Energy Technology Data Exchange (ETDEWEB)

    Geach, J. E.; Coppin, K. E. K.; Smith, D. J. B. [Center for Astrophysics Research, Science and Technology Research Institute, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom); Bower, R. G.; Alexander, D. M.; Swinbank, A. M. [Institute for Computational Cosmology, Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom); Blain, A. W. [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Bremer, M. N. [School of Physics, HH Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Chapin, E. L. [XMM SOC, ESAC, Apartado 78, E-28691 Villanueva de la Canada, Madrid (Spain); Chapman, S. C. [Department of Physics and Atmospheric Science, Dalhousie University Halifax, NS B3H 3J5 (Canada); Clements, D. L. [Astrophysics Group, Imperial College London, Blackett Laboratory, Prince Consort Road, London SW7 2AZ (United Kingdom); Dunlop, J. S.; Koprowski, M. P.; Michałowski, M. J. [Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Farrah, D. [Virginia Polytechnic Institute and State University Department of Physics, MC 0435, 910 Drillfield Drive, Blacksburg, VA 24061 (United States); Jenness, T. [Joint Astronomy Centre, 660 North A' ohoku Place University Park, Hilo, HI 96720 (United States); Robson, E. I. [UK Astronomy Technology Centre, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Scott, D. [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); Spaans, M. [Kapteyn Institute, University of Groningen, PO Box 800, 9700 AV Groningen (Netherlands); Van der Werf, P., E-mail: j.geach@herts.ac.uk [Leiden Observatory, Leiden University, PO box 9513, 2300 RA Leiden (Netherlands)

    2014-09-20

    We report the detection at 850 μm of the central source in SSA22-LAB1, the archetypal 'Lyman-α Blob' (LAB), a 100 kpc scale radio-quiet emission-line nebula at z = 3.1. The flux density of the source, S {sub 850} = 4.6 ± 1.1 mJy, implies the presence of a galaxy or group of galaxies with a total luminosity of L {sub IR} ≈ 10{sup 12} L {sub ☉}. The position of an active source at the center of a ∼50 kpc radius ring of linearly polarized Lyα emission detected by Hayes et al. suggests that the central source is leaking Lyα photons preferentially in the plane of the sky, which undergo scattering in H I clouds at a large galactocentric radius. The Lyα morphology around the submillimeter detection is reminiscent of a biconical outflow, and the average Lyα line profiles of the two 'lobes' are dominated by a red peak, which is expected for a resonant line emerging from a medium with a bulk velocity gradient that is outflowing relative to the line center. Taken together, these observations provide compelling evidence that the central active galaxy (or galaxies) is responsible for a large fraction of the extended Lyα emission and morphology. Less clear is the history of the cold gas in the circumgalactic medium being traced by Lyα: is it mainly pristine material accreting into the halo that has not yet been processed through an interstellar medium (ISM), now being blown back as it encounters an outflow, or does it mainly comprise gas that has been swept-up within the ISM and expelled from the galaxy?.

  4. Improved wedge method for the measurement of sub-millimeter slice thicknesses in magnetic resonance imaging.

    Science.gov (United States)

    Kanazawa, Tsutomu; Ohkubo, Masaki; Kondo, Tatsuya; Miyazawa, Takayuki; Inagawa, Shoichi

    2017-12-01

    The standard method for measuring the slice thickness of magnetic resonance images uses the inclined surface of a wedge (wedge method); it is sensitive to small increases in noise because of the differentiation of the edge response function (ERF) required. The purpose of this study was to improve the wedge method by fitting a curve to the ERF. The curve-fit function was obtained by convolving an ideal ERF (a ramp function) with a Gaussian function to represent ERF blurring. Measurements of 5- and 3-mm slice thicknesses were performed on a 3T scanner using the conventional wedge method, the improved wedge method, and another standard method using an inclined slab (slab method). Subsequently, 0.5- and 0.25-mm slice thicknesses from multiple slices acquired using a three-dimensional sequence were measured using the improved wedge method. When measuring 5-mm slices, the differences in measurements obtained using the improved wedge method and the conventional slab and wedge methods were very small: <0.6% of the 5-mm slice thickness. The difference was ≤1.7% for 3-mm slices. For 0.5- and 0.25-mm slices, the mean values obtained using the improved wedge method were 0.543 ± 0.007 mm and 0.247 ± 0.015 mm, with a 1.2 and 5.9% coefficient of variation across slices, respectively. The improved wedge method is valid and potentially applicable to the measurement of sub-millimeter slice thicknesses.

  5. Metrology Arrangement for Measuring the Positions of Mirrors of a Submillimeter Telescope

    Science.gov (United States)

    Abramovici, Alex; Bartman, Randall K.

    2011-01-01

    The position of the secondary mirror of a submillimeter telescope with respect to the primary mirror needs to be known .0.03 mm in three dimensions. At the time of this reporting, no convenient, reasonably priced arrangement that offers this capability exists. The solution proposed here relies on measurement devices developed and deployed for the GeoSAR mission, and later adapted for the ISAT (Innovative Space Based Radar Antenna Technology) demonstration. The measurement arrangement consists of four metrology heads, located on an optical bench, attached to the secondary mirror. Each metrology head has a dedicated target located at the edge of the primary mirror. One laser beam, launched from the head and returned by the target, is used to measure distance. Another beam, launched from a beacon on the target, is monitored by the metrology head and generates a measurement of the target position in the plane perpendicular to the laser beam. A 100-MHz modulation is carried by a collimated laser beam. The relevant wavelength is the RF one, 3 m, divided by two, because the light carries it to the target and back. The phase change due to travel to the target and back is measured by timing the zero-crossing of the RF modulation, using a 100-MHz clock. In order to obtain good resolution, the 100-MHz modulation signal is down-converted to 1 kHz. Then, the phase change corresponding to the round-trip to the target is carried by a 1-kHz signal. Since the 100-MHz clock beats 100,000 times during one period of the 1-kHz signal, the least-significant-bit (LSB) resolution is LSB = 0.015 mm.

  6. Correction for phase-shift deviation in a complex Fourier-transform integrated-optic spatial heterodyne spectrometer with an active phase-shift scheme.

    Science.gov (United States)

    Takada, Kazumasa; Aoyagi, Hirotaka; Okamoto, Katsunari

    2011-04-01

    We report that a spectrum can be retrieved with a planar waveguide spatial heterodyne spectrometer (SHS) incorporating an active phase-shift scheme, where the phase shifts are distributed around π/2. This was confirmed experimentally with an SHS that had 32 interleaved Mach-Zehnder interferometers and whose free spectral range was 625 GHz. The phase shifts ranged from 0.71 to 2.2 rad against the target of π/2 rad.

  7. HIFI Spectroscopy of H2O Submillimeter Lines in Nuclei of Actively Star-forming Galaxies

    Science.gov (United States)

    Liu, L.; Weiß, A.; Perez-Beaupuits, J. P.; Güsten, R.; Liu, D.; Gao, Y.; Menten, K. M.; van der Werf, P.; Israel, F. P.; Harris, A.; Martin-Pintado, J.; Requena-Torres, M. A.; Stutzki, J.

    2017-09-01

    We present a systematic survey of multiple velocity-resolved H2O spectra using Herschel/Heterodyne Instrument for the Far Infrared (HIFI) toward nine nearby actively star-forming galaxies. The ground-state and low-excitation lines (E up ≤ 130 K) show profiles with emission and absorption blended together, while absorption-free medium-excitation lines (130 K ≤ E up ≤ 350 K) typically display line shapes similar to CO. We analyze the HIFI observation together with archival SPIRE/PACS H2O data using a state-of-the-art 3D radiative transfer code that includes the interaction between continuum and line emission. The water excitation models are combined with information on the dust and CO spectral line energy distribution to determine the physical structure of the interstellar medium (ISM). We identify two ISM components that are common to all galaxies: a warm ({T}{dust}˜ 40{--}70 K), dense (n({{H}})˜ {10}5{--}{10}6 {{cm}}-3) phase that dominates the emission of medium-excitation H2O lines. This gas phase also dominates the far-IR emission and the CO intensities for {J}{up}> 8. In addition, a cold ({T}{dust}˜ 20{--}30 K), dense (n({{H}})˜ {10}4{--}{10}5 {{cm}}-3), more extended phase is present. It outputs the emission in the low-excitation H2O lines and typically also produces the prominent line absorption features. For the two ULIRGs in our sample (Arp 220 and Mrk 231) an even hotter and more compact (R s ≤ 100 pc) region is present, which is possibly linked to AGN activity. We find that collisions dominate the water excitation in the cold gas and for lines with {E}{up}≤slant 300 K and {E}{up}≤slant 800 K in the warm and hot component, respectively. Higher-energy levels are mainly excited by IR pumping.

  8. Electronic Switch Arrays for Managing Microbattery Arrays

    Science.gov (United States)

    Mojarradi, Mohammad; Alahmad, Mahmoud; Sukumar, Vinesh; Zghoul, Fadi; Buck, Kevin; Hess, Herbert; Li, Harry; Cox, David

    2008-01-01

    Integrated circuits have been invented for managing the charging and discharging of such advanced miniature energy-storage devices as planar arrays of microscopic energy-storage elements [typically, microscopic electrochemical cells (microbatteries) or microcapacitors]. The architecture of these circuits enables implementation of the following energy-management options: dynamic configuration of the elements of an array into a series or parallel combination of banks (subarrarys), each array comprising a series of parallel combination of elements; direct addressing of individual banks for charging/or discharging; and, disconnection of defective elements and corresponding reconfiguration of the rest of the array to utilize the remaining functional elements to obtain the desited voltage and current performance. An integrated circuit according to the invention consists partly of a planar array of field-effect transistors that function as switches for routing electric power among the energy-storage elements, the power source, and the load. To connect the energy-storage elements to the power source for charging, a specific subset of switches is closed; to connect the energy-storage elements to the load for discharging, a different specific set of switches is closed. Also included in the integrated circuit is circuitry for monitoring and controlling charging and discharging. The control and monitoring circuitry, the switching transistors, and interconnecting metal lines are laid out on the integrated-circuit chip in a pattern that registers with the array of energy-storage elements. There is a design option to either (1) fabricate the energy-storage elements in the corresponding locations on, and as an integral part of, this integrated circuit; or (2) following a flip-chip approach, fabricate the array of energy-storage elements on a separate integrated-circuit chip and then align and bond the two chips together.

  9. The cryomechanical design of MUSIC: a novel imaging instrument for millimeter-wave astrophysics at the Caltech Submillimeter Observatory

    Science.gov (United States)

    Hollister, Matthew I.; Czakon, Nicole G.; Day, Peter K.; Downes, Thomas P.; Duan, Ran; Gao, Jiansong; Glenn, Jason; Golwala, Sunil R.; LeDuc, Henry G.; Maloney, Philip R.; Mazin, Benjamin A.; Nguyen, Hien Trong; Noroozian, Omid; Sayers, Jack; Schlaerth, James; Siegel, Seth; Vaillancourt, John E.; Vayonakis, Anastasios; Wilson, Philip; Zmuidzinas, Jonas

    2010-07-01

    MUSIC (Multicolor Submillimeter kinetic Inductance Camera) is a new facility instrument for the Caltech Submillimeter Observatory (Mauna Kea, Hawaii) developed as a collaborative effect of Caltech, JPL, the University of Colorado at Boulder and UC Santa Barbara, and is due for initial commissioning in early 2011. MUSIC utilizes a new class of superconducting photon detectors known as microwave kinetic inductance detectors (MKIDs), an emergent technology that offers considerable advantages over current types of detectors for submillimeter and millimeter direct detection. MUSIC will operate a focal plane of 576 spatial pixels, where each pixel is a slot line antenna coupled to multiple detectors through on-chip, lumped-element filters, allowing simultaneously imaging in four bands at 0.86, 1.02, 1.33 and 2.00 mm. The MUSIC instrument is designed for closed-cycle operation, combining a pulse tube cooler with a two-stage Helium-3 adsorption refrigerator, providing a focal plane temperature of 0.25 K with intermediate temperature stages at approximately 50, 4 and 0.4 K for buffering heat loads and heat sinking of optical filters. Detector readout is achieved using semi-rigid coaxial cables from room temperature to the focal plane, with cryogenic HEMT amplifiers operating at 4 K. Several hundred detectors may be multiplexed in frequency space through one signal line and amplifier. This paper discusses the design of the instrument cryogenic hardware, including a number of features unique to the implementation of superconducting detectors. Predicted performance data for the instrument system will also be presented and discussed.

  10. Miniaturized Near Infrared Heterodyne Spectroradiometer for Monitoring CO2, CH4 and CO in the Earth Atmosphere

    Science.gov (United States)

    Klimchuk, A., Sr.; Rodin, A.; Nadezhdinskiy, A.; Churbanov, D.; Spiridonov, M.

    2014-12-01

    The paper describes the concept of a compact, lightweight heterodyne NIR spectro-radiometer suitable for atmospheric sounding with solar occultations, and the first measurement of CO2 and CH4 absorption near 1.60mm and 1.65 mm with spectral resolution l/dl ~ 5*107. Highly stabilized DFB laser was used as local oscillator, while single model quartz fiber Y-coupler served as a diplexer. Radiation mixed in the single mode fiber was detected by quadratic detector using p-i-n diode within the bandpass of ~10 MHz. Wavelength coverage of spectral measurement was provided by sweeping local oscillator frequency in the range 1,1 см-1. With the exposure time of 10 min, the absorption spectrum of the atmosphere over Moscow has been recorded with S/N ~ 300. We retrieved methane vertical profile using Tikhonov method of smooth functional, which takes into account a priori information about first guess profile. The reference to model methane profile means that the regularization procedure always selects a priorivalues unless the measurements contradict this assumption.The retrieved methane profile demonstrates higher abundances in the lower scale height compared to the assumed model profile, well expected in the megalopolis center. The retrievals sensitivity is limited by 10 ppb, with the exception of the lower part of the profile where the tendency to lower values is revealed. Thus the methane abundance variations may be evaluated with relative accuracy better than 1%, which fits the requirements of greenhouse gas monitoring. The retrievals sensitivity of CO2 is about 1-2 ppm. CO2 observations was also used to estimate stratoshere wind by doppler shift of absorption line. Due to higher spectral resolution, lower sensitivity to atmospheric temperatures and other external factors, compared to heterodyne measurements in the thermal IR spectral range, the described technique provides accuracy comparable with much more complicated high resolution measurements now used in TCCON

  11. Signal to Noise Ratio Maximization in Quiet Zone Acquisitions for Range Assessment at Sub-millimeter Wavelengths

    Directory of Open Access Journals (Sweden)

    A. Muñoz-Acevedo

    2012-06-01

    Full Text Available This paper proposes a quiet zone probing approach which deals with low dynamic range quiet zone acquisitions. Lack of dynamic range is a feature of millimeter and sub-millimeter wavelength technologies. It is consequence of the gradually smaller power generated by the instrumentation, that follows a f^α law with frequency, being α≥1 variable depending on the signal source’s technology. The proposed approach is based on an optimal data reduction scenario which redounds in a maximum signal to noise ratio increase for the signal pattern, with minimum information losses. After theoretical formulation, practical applications of the technique are proposed.

  12. Carbon nanotube nanoelectrode arrays

    Science.gov (United States)

    Ren, Zhifeng; Lin, Yuehe; Yantasee, Wassana; Liu, Guodong; Lu, Fang; Tu, Yi

    2008-11-18

    The present invention relates to microelectode arrays (MEAs), and more particularly to carbon nanotube nanoelectrode arrays (CNT-NEAs) for chemical and biological sensing, and methods of use. A nanoelectrode array includes a carbon nanotube material comprising an array of substantially linear carbon nanotubes each having a proximal end and a distal end, the proximal end of the carbon nanotubes are attached to a catalyst substrate material so as to form the array with a pre-determined site density, wherein the carbon nanotubes are aligned with respect to one another within the array; an electrically insulating layer on the surface of the carbon nanotube material, whereby the distal end of the carbon nanotubes extend beyond the electrically insulating layer; a second adhesive electrically insulating layer on the surface of the electrically insulating layer, whereby the distal end of the carbon nanotubes extend beyond the second adhesive electrically insulating layer; and a metal wire attached to the catalyst substrate material.

  13. Dynamically Reconfigurable Microphone Arrays

    Science.gov (United States)

    2011-05-01

    Static + 2 Wireless Using only a standard computer sound card, a robot is limited to binaural inputs. Even when using wireless microphones, the audio...Abstract—Robotic sound localization has traditionally been restricted to either on-robot microphone arrays or embedded microphones in aware...a microphone array has a significant impact on the mathematics of sound source localization. Arrays, for instance, are commonly designed to

  14. Rectenna array measurement results

    Science.gov (United States)

    Dickinson, R. M.

    1980-01-01

    The measured performance characteristics of a rectenna array are reviewed and compared to the performance of a single element. It is shown that the performance may be extrapolated from the individual element to that of the collection of elements. Techniques for current and voltage combining were demonstrated. The array performance as a function of various operating parameters is characterized and techniques for overvoltage protection and automatic fault clearing in the array demonstrated. A method for detecting failed elements also exists. Instrumentation for deriving performance effectiveness is described. Measured harmonic radiation patterns and fundamental frequency scattered patterns for a low level illumination rectenna array are presented.

  15. Integrated Avalanche Photodiode arrays

    Energy Technology Data Exchange (ETDEWEB)

    Harmon, Eric S.

    2017-04-18

    The present disclosure includes devices for detecting photons, including avalanche photon detectors, arrays of such detectors, and circuits including such arrays. In some aspects, the detectors and arrays include a virtual beveled edge mesa structure surrounded by resistive material damaged by ion implantation and having side wall profiles that taper inwardly towards the top of the mesa structures, or towards the direction from which the ion implantation occurred. Other aspects are directed to masking and multiple implantation and/or annealing steps. Furthermore, methods for fabricating and using such devices, circuits and arrays are disclosed.

  16. Integrated avalanche photodiode arrays

    Science.gov (United States)

    Harmon, Eric S.

    2015-07-07

    The present disclosure includes devices for detecting photons, including avalanche photon detectors, arrays of such detectors, and circuits including such arrays. In some aspects, the detectors and arrays include a virtual beveled edge mesa structure surrounded by resistive material damaged by ion implantation and having side wall profiles that taper inwardly towards the top of the mesa structures, or towards the direction from which the ion implantation occurred. Other aspects are directed to masking and multiple implantation and/or annealing steps. Furthermore, methods for fabricating and using such devices, circuits and arrays are disclosed.

  17. High spatial resolution brain functional MRI using submillimeter balanced steady-state free precession acquisition

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Pei-Hsin; Chung, Hsiao-Wen [Department of Electrical Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Tsai, Ping-Huei [Imaging Research Center, Taipei Medical University, Taipei 11031, Taiwan and Department of Medical Imaging, Taipei Medical University Hospital, Taipei Medical University, Taipei 11031, Taiwan (China); Wu, Ming-Long, E-mail: minglong.wu@csie.ncku.edu.tw [Institute of Medical Informatics, National Cheng-Kung University, Tainan 70101, Taiwan and Department of Computer Science and Information Engineering, National Cheng-Kung University, Tainan 70101, Taiwan (China); Chuang, Tzu-Chao [Department of Electrical Engineering, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan (China); Shih, Yi-Yu [Siemens Limited Healthcare Sector, Taipei 11503, Taiwan (China); Huang, Teng-Yi [Department of Electrical Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China)

    2013-12-15

    Purpose: One of the technical advantages of functional magnetic resonance imaging (fMRI) is its precise localization of changes from neuronal activities. While current practice of fMRI acquisition at voxel size around 3 × 3 × 3 mm{sup 3} achieves satisfactory results in studies of basic brain functions, higher spatial resolution is required in order to resolve finer cortical structures. This study investigated spatial resolution effects on brain fMRI experiments using balanced steady-state free precession (bSSFP) imaging with 0.37 mm{sup 3} voxel volume at 3.0 T. Methods: In fMRI experiments, full and unilateral visual field 5 Hz flashing checkerboard stimulations were given to healthy subjects. The bSSFP imaging experiments were performed at three different frequency offsets to widen the coverage, with functional activations in the primary visual cortex analyzed using the general linear model. Variations of the spatial resolution were achieved by removing outerk-space data components. Results: Results show that a reduction in voxel volume from 3.44 × 3.44 × 2 mm{sup 3} to 0.43 × 0.43 × 2 mm{sup 3} has resulted in an increase of the functional activation signals from (7.7 ± 1.7)% to (20.9 ± 2.0)% at 3.0 T, despite of the threefold SNR decreases in the original images, leading to nearly invariant functional contrast-to-noise ratios (fCNR) even at high spatial resolution. Activation signals aligning nicely with gray matter sulci at high spatial resolution would, on the other hand, have possibly been mistaken as noise at low spatial resolution. Conclusions: It is concluded that the bSSFP sequence is a plausible technique for fMRI investigations at submillimeter voxel widths without compromising fCNR. The reduction of partial volume averaging with nonactivated brain tissues to retain fCNR is uniquely suitable for high spatial resolution applications such as the resolving of columnar organization in the brain.

  18. Kilovoltage beam Monte Carlo dose calculations in submillimeter voxels for small animal radiotherapy.

    Science.gov (United States)

    Bazalova, Magdalena; Zhou, Hu; Keall, Paul J; Graves, Edward E

    2009-11-01

    Small animal conformal radiotherapy (RT) is essential for preclinical cancer research studies and therefore various microRT systems have been recently designed. The aim of this paper is to efficiently calculate the dose delivered using our microRT system based on a microCT scanner with the Monte Carlo (MC) method and to compare the MC calculations to film measurements. Doses from 2-30 mm diameter 120 kVp photon beams deposited in a solid water phantom with 0.2 x 0.2 x 0.2 mm3 voxels are calculated using the latest versions of the EGSnrc codes BEAMNRC and DOSXYZNRC. Two dose calculation approaches are studied: a two-step approach using phase-space files and direct dose calculation with BEAMNRC simulation sources. Due to the small beam size and submillimeter voxel size resulting in long calculation times, variance reduction techniques are studied. The optimum bremsstrahlung splitting number (NBRSPL in BEAMNRC) and the optimum DOSXYZNRC photon splitting (Nsplit) number are examined for both calculation approaches and various beam sizes. The dose calculation efficiencies and the required number of histories to achieve 1% statistical uncertainty--with no particle recycling--are evaluated for 2-30 mm beams. As a final step, film dose measurements are compared to MC calculated dose distributions. The optimum NBRSPL is approximately 1 x 10(6) for both dose calculation approaches. For the dose calculations with phase-space files, Nsplit varies only slightly for 2-30 mm beams and is established to be 300. Nsplit for the DOSXYZNRC calculation with the BEAMNRC source ranges from 300 for the 30 mm beam to 4000 for the 2 mm beam. The calculation time significantly increases for small beam sizes when the BEAMNRC simulation source is used compared to the simulations with phase-space files. For the 2 and 30 mm beams, the dose calculations with phase-space files are more efficient than the dose calculations with BEAMNRC sources by factors of 54 and 1.6, respectively. The dose

  19. The Interstellar Medium in High-redshift Submillimeter Galaxies as Probed by Infrared Spectroscopy*

    Science.gov (United States)

    Wardlow, Julie L.; Cooray, Asantha; Osage, Willow; Bourne, Nathan; Clements, David; Dannerbauer, Helmut; Dunne, Loretta; Dye, Simon; Eales, Steve; Farrah, Duncan; Furlanetto, Cristina; Ibar, Edo; Ivison, Rob; Maddox, Steve; Michałowski, Michał M.; Riechers, Dominik; Rigopoulou, Dimitra; Scott, Douglas; Smith, Matthew W. L.; Wang, Lingyu; van der Werf, Paul; Valiante, Elisabetta; Valtchanov, Ivan; Verma, Aprajita

    2017-03-01

    Submillimeter galaxies (SMGs) at z≳ 1 are luminous in the far-infrared, and have star formation rates, SFR, of hundreds to thousands of solar masses per year. However, it is unclear whether they are true analogs of local ULIRGs or whether the mode of their star formation is more similar to that in local disk galaxies. We target these questions by using Herschel-PACS to examine the conditions in the interstellar medium (ISM) in far-infrared luminous SMGs at z˜ 1-4. We present 70-160 μm photometry and spectroscopy of the [O IV]26 μm, [Fe II]26 μm, [S III]33 μm, [Si II]34 μm, [O III]52 μm, [N III]57 μm, and [O I]63 μm fine-structure lines and the S(0) and S(1) hydrogen rotational lines in 13 lensed SMGs identified by their brightness in early Herschel data. Most of the 13 targets are not individually spectroscopically detected; we instead focus on stacking these spectra with observations of an additional 32 SMGs from the Herschel archive—representing a complete compilation of PACS spectroscopy of SMGs. We detect [O I]63 μm, [Si II]34 μm, and [N III]57 μm at ≥slant 3σ in the stacked spectra, determining that the average strengths of these lines relative to the far-IR continuum are (0.36+/- 0.12)× {10}-3, (0.84+/- 0.17)× {10}-3, and (0.27+/- 0.10)× {10}-3, respectively. Using the [O III]52 μm/[N III]57 μm emission line ratio, we show that SMGs have average gas-phase metallicities ≳ {Z}⊙ . By using PDR modeling and combining the new spectral measurements with integrated far-infrared fluxes and existing [C II]158 μm data, we show that SMGs have average gas densities, n, of ˜ {10}1-3 {{cm}}-3 and FUV field strengths, {G}0˜ {10}2.2-4.5 (in Habing units: 1.6× {10}-3 {erg} {{cm}}-2 {{{s}}}-1), consistent with both local ULIRGs and lower luminosity star-forming galaxies. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia, and important participation from NASA.

  20. Performance Assessment of a Plate Beam Splitter for Deep-Ultraviolet Raman Measurements with a Spatial Heterodyne Raman Spectrometer.

    Science.gov (United States)

    Lamsal, Nirmal; Angel, S Michael

    2017-06-01

    In earlier works, we demonstrated a high-resolution spatial heterodyne Raman spectrometer (SHRS) for deep-ultraviolet (UV) Raman measurements, and showed its ability to measure UV light-sensitive compounds using a large laser spot size. We recently modified the SHRS by replacing the cube beam splitter (BS) with a custom plate beam splitter with higher light transmission, an optimized reflectance/transmission ratio, higher surface flatness, and better refractive index homogeneity than the cube beam splitter. Ultraviolet Raman measurements were performed using a SHRS modified to use the plate beam splitter and a matching compensator plate and compared to the previously described cube beam splitter setup. Raman spectra obtained using the modified SHRS exhibit much higher signals and signal-to-noise (S/N) ratio and show fewer spectral artifacts. In this paper, we discuss the plate beam splitter SHRS design features, the advantages over previous designs, and discuss some general SHRS issues such as spectral bandwidth, S/N ratio characteristics, and optical efficiency.

  1. Phase-Resolved Heterodyne-Detected Transient Grating Enhances the Capabilities of 2D IR Echo Spectroscopy.

    Science.gov (United States)

    Jin, Geun Young; Kim, Yung Sam

    2017-02-09

    2D IR echo spectroscopy, with high sensitivity and femtosecond time resolution, enables us to understand structure and ultrafast dynamics of molecular systems. Application of this experimental technique on weakly absorbing samples, however, had been limited by the precise and unambiguous phase determination of the echo signals. In this study, we propose a new experimental scheme that significantly increases the phase stability of the involved IR pulses. We have demonstrated that the incorporation of phase-resolved heterodyne-detected transient grating (PR-HDTG) spectroscopy greatly enhances the capabilities of 2D IR spectroscopy. The new experimental scheme has been used to obtain 2D IR spectra on weakly absorbing azide ions (N3-) in H2O (absorbance ∼0.025), free of phase ambiguity even at large waiting times. We report the estimated spectral diffusion time scale (1.056 ps) of azide ions in aqueous solution from the 2D IR spectra and the vibrational lifetime (750 ± 3 fs) and the reorientation time (1108 ± 24 fs) from the PR-HDTG spectra.

  2. The Effect of Trifluoroethanol and Glycerol on the Thermal Properties of Collagen Using Optical Displacement-Enhanced Heterodyne Polarimeter

    Directory of Open Access Journals (Sweden)

    Chien-Ming Wu

    2015-11-01

    Full Text Available An angular displacement-enhanced heterodyne polarimeter has been employed to investigate the interplay between trifluoroethanol (TFE and glycerol on the thermal denaturation of type I collagen. The concentration of the collagen solution was fixed at 0.341 (mg/mL, and was heated from 25 °C to 55 °C. TFE solutions with concentrations of 5%, 10%, 15%, 20%, 40% and 80% (v/v were prepared and the phase change was recorded for the determination of thermal denaturation. It was observed that the thermal denaturation temperature (Td is decreased with increasing TFE concentration due to the partial cleavage of the triple-helical structure. With TFE concentration higher than 20% (v/v, the degree of optical rotation appears to be nearly the same, reflecting that the collagen triple helices have been completely destructed. Moreover, the addition of glycerol in inhibiting the thermal denaturation of collagen is investigated. It has been shown that glycerol can improve the thermal denaturation of both collagen and TFE-mixed collagen. Experimental results show that, in the presence of 2 M glycerol, the Td of collagen remained at around 41.9 °C, meanwhile the Td of 20% (v/v TFE-mixed collagen is significantly restored to 32.8 °C.

  3. A comparison between heterodyne and homodyne interferometry to realise the SI unit of acoustic pressure in water

    Science.gov (United States)

    Koukoulas, Triantafillos; Robinson, Stephen; Rajagopal, Srinath; Zeqiri, Bajram

    2016-04-01

    Optical approaches for hydrophone calibrations offer significant advantages over existing methods based on reciprocity. In particular, heterodyne and homodyne interferometry can accurately measure particle velocity and displacements at a specific point in space thus enabling the acoustical pressure to be measured in an absolute, direct, assumption-free manner, with traceability through the SI definition of the metre. The calibration of a hydrophone can then be performed by placing the active element of the sensor at the point where the acoustic pressure field was measured and monitoring its electrical output. However, it is crucial to validate the performance and accuracy of such optical methods by direct comparison rather than through device calibration. Here we report on the direct comparison of two such optical interferometers used in underwater acoustics and ultrasonics in terms of acoustic pressure estimation and their associated uncertainties in the frequency range 200 kHz-3.5 MHz, with results showing agreement better than 1% in terms of pressure and typical expanded uncertainties better than 3% for both reported methods.

  4. Infrared laser transillumination CT imaging system using parallel fiber arrays and optical switches for finger joint imaging

    Science.gov (United States)

    Sasaki, Yoshiaki; Emori, Ryota; Inage, Hiroki; Goto, Masaki; Takahashi, Ryo; Yuasa, Tetsuya; Taniguchi, Hiroshi; Devaraj, Balasigamani; Akatsuka, Takao

    2004-05-01

    The heterodyne detection technique, on which the coherent detection imaging (CDI) method founds, can discriminate and select very weak, highly directional forward scattered, and coherence retaining photons that emerge from scattering media in spite of their complex and highly scattering nature. That property enables us to reconstruct tomographic images using the same reconstruction technique as that of X-Ray CT, i.e., the filtered backprojection method. Our group had so far developed a transillumination laser CT imaging method based on the CDI method in the visible and near-infrared regions and reconstruction from projections, and reported a variety of tomographic images both in vitro and in vivo of biological objects to demonstrate the effectiveness to biomedical use. Since the previous system was not optimized, it took several hours to obtain a single image. For a practical use, we developed a prototype CDI-based imaging system using parallel fiber array and optical switches to reduce the measurement time significantly. Here, we describe a prototype transillumination laser CT imaging system using fiber-optic based on optical heterodyne detection for early diagnosis of rheumatoid arthritis (RA), by demonstrating the tomographic imaging of acrylic phantom as well as the fundamental imaging properties. We expect that further refinements of the fiber-optic-based laser CT imaging system could lead to a novel and practical diagnostic tool for rheumatoid arthritis and other joint- and bone-related diseases in human finger.

  5. LUPUS I observations from the 2010 flight of the Balloon-borne large aperture submillimeter telescope for polarimetry

    Energy Technology Data Exchange (ETDEWEB)

    Matthews, Tristan G.; Chapman, Nicholas L.; Novak, Giles [Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) and Department of Physics and Astronomy, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 (United States); Ade, Peter A. R.; Hargrave, Peter C.; Nutter, David [Cardiff University, School of Physics and Astronomy, Queens Buildings, The Parade, Cardiff, CF24 3AA (United Kingdom); Angilè, Francesco E.; Devlin, Mark J.; Klein, Jeffrey [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104 (United States); Benton, Steven J.; Fissel, Laura M.; Gandilo, Natalie N.; Netterfield, Calvin B. [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street Toronto, ON M5S 3H4 (Canada); Chapin, Edward L. [XMM SOC, ESAC, Apartado 78, E-28691 Villanueva de la Cañada, Madrid (Spain); Fukui, Yasuo [Department of Physics, Nagoya University, Nagoya 464-8602 (Japan); Gundersen, Joshua O. [Department of Physics, University of Miami, 1320 Campo Sano Drive, Coral Gables, FL 33146 (United States); Korotkov, Andrei L. [Department of Physics, Brown University, 182 Hope Street, Providence, RI 02912 (United States); Moncelsi, Lorenzo; Mroczkowski, Tony K. [California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Olmi, Luca [University of Puerto Rico, Rio Piedras Campus, Physics Department, Box 23343, UPR station, San Juan (Puerto Rico); and others

    2014-04-01

    The Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry (BLASTPol) was created by adding polarimetric capability to the BLAST experiment that was flown in 2003, 2005, and 2006. BLASTPol inherited BLAST's 1.8 m primary and its Herschel/SPIRE heritage focal plane that allows simultaneous observation at 250, 350, and 500 μm. We flew BLASTPol in 2010 and again in 2012. Both were long duration Antarctic flights. Here we present polarimetry of the nearby filamentary dark cloud Lupus I obtained during the 2010 flight. Despite limitations imposed by the effects of a damaged optical component, we were able to clearly detect submillimeter polarization on degree scales. We compare the resulting BLASTPol magnetic field map with a similar map made via optical polarimetry. (The optical data were published in 1998 by J. Rizzo and collaborators.) The two maps partially overlap and are reasonably consistent with one another. We compare these magnetic field maps to the orientations of filaments in Lupus I, and we find that the dominant filament in the cloud is approximately perpendicular to the large-scale field, while secondary filaments appear to run parallel to the magnetic fields in their vicinities. This is similar to what is observed in Serpens South via near-IR polarimetry, and consistent with what is seen in MHD simulations by F. Nakamura and Z. Li.

  6. Coded SQUID arrays

    NARCIS (Netherlands)

    Podt, M.; Weenink, J.; Weenink, J.; Flokstra, Jakob; Rogalla, Horst

    2001-01-01

    We report on a superconducting quantum interference device (SQUID) system to read out large arrays of cryogenic detectors. In order to reduce the number of SQUIDs required for an array of these detectors, we used code-division multiplexing. This simplifies the electronics because of a significantly

  7. Microfabricated ion trap array

    Science.gov (United States)

    Blain, Matthew G [Albuquerque, NM; Fleming, James G [Albuquerque, NM

    2006-12-26

    A microfabricated ion trap array, comprising a plurality of ion traps having an inner radius of order one micron, can be fabricated using surface micromachining techniques and materials known to the integrated circuits manufacturing and microelectromechanical systems industries. Micromachining methods enable batch fabrication, reduced manufacturing costs, dimensional and positional precision, and monolithic integration of massive arrays of ion traps with microscale ion generation and detection devices. Massive arraying enables the microscale ion traps to retain the resolution, sensitivity, and mass range advantages necessary for high chemical selectivity. The reduced electrode voltage enables integration of the microfabricated ion trap array with on-chip circuit-based rf operation and detection electronics (i.e., cell phone electronics). Therefore, the full performance advantages of the microfabricated ion trap array can be realized in truly field portable, handheld microanalysis systems.

  8. Sensor array signal processing

    CERN Document Server

    Naidu, Prabhakar S

    2009-01-01

    Chapter One: An Overview of Wavefields 1.1 Types of Wavefields and the Governing Equations 1.2 Wavefield in open space 1.3 Wavefield in bounded space 1.4 Stochastic wavefield 1.5 Multipath propagation 1.6 Propagation through random medium 1.7 ExercisesChapter Two: Sensor Array Systems 2.1 Uniform linear array (ULA) 2.2 Planar array 2.3 Distributed sensor array 2.4 Broadband sensor array 2.5 Source and sensor arrays 2.6 Multi-component sensor array2.7 ExercisesChapter Three: Frequency Wavenumber Processing 3.1 Digital filters in the w-k domain 3.2 Mapping of 1D into 2D filters 3.3 Multichannel Wiener filters 3.4 Wiener filters for ULA and UCA 3.5 Predictive noise cancellation 3.6 Exercises Chapter Four: Source Localization: Frequency Wavenumber Spectrum4.1 Frequency wavenumber spectrum 4.2 Beamformation 4.3 Capon's w-k spectrum 4.4 Maximum entropy w-k spectrum 4.5 Doppler-Azimuth Processing4.6 ExercisesChapter Five: Source Localization: Subspace Methods 5.1 Subspace methods (Narrowband) 5.2 Subspace methods (B...

  9. SUB-MILLIMETER TELESCOPE CO (2-1) OBSERVATIONS OF NEARBY STAR-FORMING GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Xue-Jian; Gu, Qiusheng [School of Astronomy and Space Science, Nanjing University, Nanjing 210093 (China); Wang, Zhong [Harvard-Smithsonian Center for Astrophysics, MS 66, 60 Garden Street, Cambridge, MA 02138 (United States); Wang, Junzhi [Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030 (China); Zhang, Zhi-Yu, E-mail: xjjiang@nju.edu.cn [The UK Astronomy Technology Centre, Royal Observatory Edinburgh, Blackford Hill, Edinburgh, EH9 3HJ (United Kingdom)

    2015-01-20

    We present CO J = 2-1 observations toward 32 nearby gas-rich star-forming galaxies selected from the ALFALFA and Wide-field Infrared Survey Explorer (WISE) catalogs, using the Sub-millimeter Telescope (SMT). Our sample is selected to be dominated by intermediate-M {sub *} galaxies. The scaling relations between molecular gas, atomic gas, and galactic properties (stellar mass, NUV – r, and WISE color W3 – W2) are examined and discussed. Our results show the following. (1) In the galaxies with stellar mass M {sub *} ≤10{sup 10} M {sub ☉}, the H I fraction (f {sub H} {sub I} ≡ M {sub H} {sub I}/M {sub *}) is significantly higher than that of more massive galaxies, while the H{sub 2} gas fraction (f{sub H{sub 2}} ≡ M{sub H{sub 2}}/M {sub *}) remains nearly unchanged. (2) Compared to f{sub H{sub 2}}, f {sub H} {sub I} correlates better with both M {sub *} and NUV – r. (3) A new parameter, WISE color W3 – W2 (12-4.6 μm), is introduced, which is similar to NUV – r in tracing star formation activity, and we find that W3 – W2 has a tighter anti-correlation with log f{sub H{sub 2}} than the anti-correlation of (NUV – r)-f {sub H} {sub I}, (NUV – r)-f{sub H{sub 2}}, and (W3 – W2)-f {sub H} {sub I}. This indicates that W3 – W2 can trace the H{sub 2} fraction in galaxies. For the gas ratio M{sub H{sub 2}}/M {sub H} {sub I} , only in the intermediate-M {sub *} galaxies it appears to depend on M {sub *} and NUV – r. We find a tight correlation between the molecular gas mass M{sub H{sub 2}} and 12 μm (W3) luminosities (L {sub 12} {sub μm}), and the slope is close to unity (1.03 ± 0.06) for the SMT sample. This correlation may reflect that the cold gas and dust are well mixed on a global galactic scale. Using the all-sky 12 μm (W3) data available in WISE, this correlation can be used to estimate CO flux for molecular gas observations and can even predict H{sub 2} mass for star-forming galaxies.

  10. Simulation study for the Stratospheric Inferred Wind (SIW) sub-millimeter limb sounder

    Science.gov (United States)

    Baron, Philippe; Murtagh, Donal; Eriksson, Patrick; Ochiai, Satoshi

    2017-04-01

    -and-aac-microtec-to-develop-the-innosat-platform-and-implement-its-first-mission-named-mats.html [2] Wu D., et al.: Mesospheric Doppler wind measurements from Aura Microwave Limb Sounder (MLS), Advanced in Space Research, 42, 1246-1252, 2008 [3] Baron P., et al.: Observation of horizontal winds in the middle-atmosphere between 30S and 55N during the northern winter 2009-2010, Atmospheric Chemistry and Physics 13(13), 6049-6064, 2013, doi:10.5194/acp-13-6049-2013 [4] Baron P., et al.: Definition of an uncooled submillimeter/terahertz limb sounder for measuring middle atmospheric winds, Proceedings of ESA Living Planet Symposium, Edinburgh, UK, 9-13 September 2013, (ESA SP-722, December 2013)

  11. Development of a heterodyne micro-wave reflectometer with ultra-fast sweeping. The study of the plasma turbulence influence on the measurements of electron density profile; Developppement d`un reflectometre micro-onde heterodyne a balayage ultra rapide. Etude de l`influence de la turbulence du plasma sur la mesure des profils de densite electronique

    Energy Technology Data Exchange (ETDEWEB)

    Moreau, Philippe [Aix-Marseille-1 Univ., 13 - Marseille (France)

    1997-10-17

    The density profile of the fusion plasmas can be investigated by the reflectometry diagnostics. The measurement principle is based on the radar techniques which calculate the phase shift of a millimeter wave propagating into the plasma and reflected at a cut-off layer. However, this propagation is perturbed by the plasma turbulence. These phenomena affect the phase delay measurement by not well understood a process. In this work we have tried to find the mechanisms and origin of the turbulence which is responsible for the phase disturbance. We point out the role of collisionality and plasma radiation in controlling the instability and also, demonstrate that the phase delay of the probing wave is very sensitive to the plasma MHD phenomena and is less affected by the micro-turbulence. The second part of this work is the development and the use of a new heterodyne reflectometer. The principal characteristics are given. Its heterodyne detection allows the separation of phase and amplitude information from the detected signal and then to study their contribution to the mechanism of signal perturbation. The use of this reflectometer allows us to point out the following points: - a high dynamic availability, required by the large amplitude drops, often greater than 30 db; - fast sweep operation requirement to `freeze` the plasma turbulence; - multiple reflection effects which modulate the amplitude and phase of the probing wave if they are not suppressed by filtering the detected signal; - very good localisation of the measurement (of the order of millimeter). The heterodyne reflectometer developed during this work offers several advantages of different distinct reflectometry techniques (fast sweep, absolute and differential phase measurements, heterodyne detection). It could be developed to work over higher frequency range so as to measure density profile over larger radial extension with very high performances. (author) 93 refs., 101 figs., 8 tabs. 3 ills.

  12. Piezoelectric transducer array microspeaker

    KAUST Repository

    Carreno, Armando Arpys Arevalo

    2016-12-19

    In this paper we present the fabrication and characterization of a piezoelectric micro-speaker. The speaker is an array of micro-machined piezoelectric membranes, fabricated on silicon wafer using advanced micro-machining techniques. Each array contains 2n piezoelectric transducer membranes, where “n” is the bit number. Every element of the array has a circular shape structure. The membrane is made out four layers: 300nm of platinum for the bottom electrode, 250nm or lead zirconate titanate (PZT), a top electrode of 300nm and a structural layer of 50

  13. Lineshape and Sensitivity of Spectroscopic Signals of N_2^+ in a Positive Column Collected Using Noise Immune Cavity Enhanced Optical Heterodyne Velocity Modulation Spectroscopy

    Science.gov (United States)

    Mills, Rew; Siller, Brian; Porambo, Michael; McCall, Benjamin J.

    2011-06-01

    Challenges to studying gas phase ions include the dilute analyte, Doppler line broadening, and a lack of ion/neutral discrimination. Techniques which provide high sensitivity, sub-Doppler features, and some form of ion/neutral discrimination increase the ability to study gas phase ions. Recently our group has used noise immune cavity enhanced optical heterodyne velocity modulated spectroscopy (NICE-OHVMS) to help overcome each of these challenges. Using NICE-OHMS to probe a velocity modulated positive column produces a distinctive line shape. The high optical power from and geometry of the cavity saturates optical transitions and allows sub-Doppler Lamb dips to be observed. Depending on sideband frequency (1 or 9 times the free spectral range) the sub-Doppler features are closer together or further apart. The sub-Doppler features can then be used to measure the line-centers with high (˜1 MHz) precision and accuracy using an optical frequency comb. The Kramers-Kronig relations describe how the absorption and dispersion are related to one another and can be used to obtain the absorption from the dispersion (and vice-versa). Owing to the phase dependent absorption signal produced with heterodyne spectroscopy, both absorption and dispersion signals can be obtained simultaneously. Two RF mixers (one for absorption and one for dispersion), each driving its own lock-in amplifier, are used to obtain a signal for ions and excited neutrals. We will report a comparison of the sensitivities of several absorbance techniques to study a nitrogenic velocity modulated positive column including: direct absorption, cavity enhanced velocity modulation, heterodyne spectroscopy and NICE-OHMS, and show how the signal-to-noise ratio is increased by using NICE-OHMS. Future plans for this technique include using a high power cw-OPO in the mid-IR to perform high precision vibrational spectroscopy of ions such as CH_5^+.

  14. Submillimeter H2O and H2O+emission in lensed ultra- and hyper-luminous infrared galaxies at z 2-4

    NARCIS (Netherlands)

    Yang, C.; Omont, A.; Beelen, A.; González-Alfonso, E.; Neri, R.; Gao, Y.; van der Werf, P.; Weiß, A.; Gavazzi, R.; Falstad, N.; Baker, A. J.; Bussmann, R. S.; Cooray, A.; Cox, P.; Dannerbauer, H.; Dye, S.; Guélin, M.; Ivison, R.; Krips, M.; Lehnert, M.; Michałowski, M. J.; Riechers, D. A.; Spaans, M.; Valiante, E.

    2016-01-01

    We report rest-frame submillimeter H2O emission line observations of 11 ultra- or hyper-luminous infrared galaxies (ULIRGs or HyLIRGs) at z 2-4 selected among the brightest lensed galaxies discovered in the Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS). Using the IRAM NOrthern

  15. Broadband mid-infrared and THz chemical detection with quantum cascade laser multi-heterodyne spectrometers (Conference Presentation)

    Science.gov (United States)

    Westberg, Jonas; Sterczewski, Lukasz A.; Patrick, Link; Wysocki, Gerard

    2017-05-01

    Majority of chemical species of interest in security and safety applications (e.g. explosives) have complex molecular structures that produce unresolved rotational-vibrational spectroscopic signatures in the mid-infrared. This requires spectroscopic techniques that can provide broadband coverage in the mid-IR region to target broadband absorbers and high resolution to address small molecules that exhibit well-resolved spectral lines. On the other hand, many broadband mid-IR absorbers exhibit well-resolved rotational components in the THz spectral region. Thus, development of spectroscopic sensing technologies that can address both spectral regions is of great importance. Here we demonstrate recent progress towards broadband high-resolution spectroscopic sensing applications with Fabry-Perot quantum cascade lasers (QCLs) and frequency combs using multi-heterodyne spectroscopy (MHS) techniques. In this paper, we will present spectroscopic sensing of large and small molecules in the mid-IR region using QCLs operating at 8.5µm. An example high-resolution, broadband MHS of ammonia (small molecule) and isobutane (broadband absorber) at atmospheric pressure in the 1165-1190 cm^-1 range will be discussed. We have developed a balanced MHS system for mitigation of the laser intensity fluctuations. Absorption spectroscopy as well as dispersion spectroscopy with minimum fractional absorption down to 10^-4/Hz1/2 and fast spectral acquisition capabilities down to 10 µs/spectrum range will be demonstrated. In order to mitigate the shortcomings of the limited chemical selectivity in the mid-IR, THz QCL based spectrometer is currently under development to provide spectral de-congestion and thus significantly improve chemical identification. Preliminary characterization of the performance of THZ QCL combs for the THz QCL-MHS will be presented.

  16. Vertical profiling of CH4 and CO2 based on high resolution ground-based NIR heterodyne spectro-radiometry

    Science.gov (United States)

    Klimchuk, Artem; Rodin, Alexander V.; Nadezhdinskii, Alexander; Spiridonov, Maxim; Churbanov, Dmitriy

    A compact, lightweight heterodyne NIR spectro-radiometer suitable for ground-based atmospheric sounding by direct spectro-radimetry of Sun spectrum with spectral resolution lambda / deltalambda=5*10 (7) has been used for precise measurements and vertical profiling of methane and carbon dioxide. Highly stabilized DFB laser was used as local oscillator, while single model quartz fiber Y-coupler served as a diplexer. Radiation mixed in the single mode fiber was detected by quadratic detector using p-i-n diode within the bandpass of 10 MHz. Wavelength coverage of spectral measurement was provided by sweeping local oscillator frequency in the range 1,1 cm (-1) . With the exposure time of 15 min, the absorption spectrum of the atmosphere over Moscow has been recorded with S/N=300. We retrieved methane vertical profile using Tikhonov method of smooth functional, which takes into account a priori information about first guess profile. The reference to model methane profile means that the regularization procedure always selects a priori values unless the measurements contradict this assumption. The retrieved methane profile demonstrates higher abundances in the lower scale height compared to the assumed model profile, well expected in the megalopolis center. The retrievals sensitivity is limited by 10 ppb, with the exception of the lower part of the profile where the tendency to lower values is revealed. Thus the methane abundance variations may be evaluated with relative accuracy better than 1%, which fits the requirements of greenhouse gas monitoring. The CO2 profile has also been retrieved with the accuracy sufficient for analyzing regional sources of greenhouse gases.

  17. 100-GHz Wireless-Over-Fiber Links With Up to 16-Gb/s QPSK Modulation Using Optical Heterodyne Generation and Digital Coherent Detection

    DEFF Research Database (Denmark)

    Sambaraju, R.; Zibar, Darko; Caballero Jambrina, Antonio

    2010-01-01

    -running unmodulated laser for the wireless signal generation is employed. To correct for the phase and frequency offset originating from the heterodyne mixing of the two free-running lasers, wireless signal demodulation based on optical coherent detection in combination with baseband digital signal processing...... is implemented. As a proof of concept, 5-Gb/s amplitude-shift keying and up to a 16-Gb/s QPSK wireless signal in the band of 75–110 GHz was generated and successfully demodulated. All-photonic millimeter-wave wireless signal generation and digital coherent detection at baud-rate are employed without complex...

  18. Design of Infrasonic Arrays

    National Research Council Canada - National Science Library

    Blandford, Robert

    1997-01-01

    The Infrasound Experts Group of the Geneva Conference on Disarmament Ad Hoc Committee on a Nuclear Test Ban has recommended an infrasound array design consisting of four elements, with three elements...

  19. Protein Functionalized Nanodiamond Arrays

    Directory of Open Access Journals (Sweden)

    Liu YL

    2010-01-01

    Full Text Available Abstract Various nanoscale elements are currently being explored for bio-applications, such as in bio-images, bio-detection, and bio-sensors. Among them, nanodiamonds possess remarkable features such as low bio-cytotoxicity, good optical property in fluorescent and Raman spectra, and good photostability for bio-applications. In this work, we devise techniques to position functionalized nanodiamonds on self-assembled monolayer (SAMs arrays adsorbed on silicon and ITO substrates surface using electron beam lithography techniques. The nanodiamond arrays were functionalized with lysozyme to target a certain biomolecule or protein specifically. The optical properties of the nanodiamond-protein complex arrays were characterized by a high throughput confocal microscope. The synthesized nanodiamond-lysozyme complex arrays were found to still retain their functionality in interacting with E. coli.

  20. Expandable LED array interconnect

    Science.gov (United States)

    Yuan, Thomas Cheng-Hsin; Keller, Bernd

    2011-03-01

    A light emitting device that can function as an array element in an expandable array of such devices. The light emitting device comprises a substrate that has a top surface and a plurality of edges. Input and output terminals are mounted to the top surface of the substrate. Both terminals comprise a plurality of contact pads disposed proximate to the edges of the substrate, allowing for easy access to both terminals from multiple edges of the substrate. A lighting element is mounted to the top surface of the substrate. The lighting element is connected between the input and output terminals. The contact pads provide multiple access points to the terminals which allow for greater flexibility in design when the devices are used as array elements in an expandable array.

  1. The retinal readout array

    Science.gov (United States)

    Litke, Alan; Meister, Markus

    1991-12-01

    We have fabricated and tested a set of electrode arrays for the study of information processing in the retina. Live retinal tissue is placed on top of an array with the output neurons directly above the electrodes. Absorption of light by the photoreceptor cells leads to the generation of electrical pulses in the output neurons. These pulses, in turn, produce voltage signals on the electrodes which are recorded simultaneously by external electronics. Thus, for the first time, the spatial and temporal firing patterns of a large set of retinal nerve cells can be studied. The arrays are fabricated on quartz wafers coated with a transparent conducting layer of indium tin oxide. The electrodes are electroplated with platinum black. Polyimide is used for insulation. The fabrication and properties of these arrays, and illustrative results with retinal tissue, are described.

  2. Developments of wide field submillimeter optics and lens antenna-coupled MKID cameras

    Science.gov (United States)

    Sekimoto, Y.; Nitta, T.; Karatsu, K.; Sekine, M.; Sekiguchi, S.; Okada, T.; Shu, S.; Noguchi, T.; Naruse, M.; Mitsui, K.; Okada, N.; Tsuzuki, T.; Dominjon, A.; Matsuo, H.

    2014-07-01

    Wide field cryogenic optics and millimeter-wave Microwave Kinetic Inductance Detector (MKID) cameras with Si lens array have been developed. MKID is a Cooper-pair breaking photon detector and consists of supercon- ducting resonators which enable microwave (~GHz) frequency multiplexing. Antenna-coupled Aluminum CPW resonators are put in a line on a Si substrate to be read by a pair of coaxial cables. A 220 GHz - 600 pixels MKID camera with anti-reflection (AR) coated Si lens has been demonstrated in an 0.1 K cryostat. A compact cryogenic system with high refractive index materials has been developed for the MKID camera.

  3. DUST AND GAS IN THE MAGELLANIC CLOUDS FROM THE HERITAGE HERSCHEL KEY PROJECT. I. DUST PROPERTIES AND INSIGHTS INTO THE ORIGIN OF THE SUBMILLIMETER EXCESS EMISSION

    Energy Technology Data Exchange (ETDEWEB)

    Gordon, Karl D.; Roman-Duval, Julia; Meixner, Margaret [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Bot, Caroline [Observatoire astronomique de Strasbourg, Université de Strasbourg, CNRS, UMR 7550, 11 rue de l Université, F-67000 Strasbourg (France); Babler, Brian [Department of Astronomy, 475 North Charter Street, University of Wisconsin, Madison, WI 53706 (United States); Bernard, Jean-Philippe [CESR, Université de Toulouse, UPS, 9 Avenue du Colonel Roche, F-31028 Toulouse, Cedex 4 (France); Bolatto, Alberto; Jameson, Katherine [Department of Astronomy, Lab for Millimeter-wave Astronomy, University of Maryland, College Park, MD 20742-2421 (United States); Boyer, Martha L. [Observational Cosmology Lab, Code 665, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Clayton, Geoffrey C. [Department of Physics and Astronomy, Louisiana State University, 233-A Nicholson Hall, Tower Drive, Baton Rouge, LA 70803 (United States); Engelbracht, Charles [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Fukui, Yasuo [Department of Physics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602 (Japan); Galametz, Maud [European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching-bei-Mnchen (Germany); Galliano, Frederic; Hony, Sacha; Lebouteiller, Vianney [CEA, Laboratoire AIM, Irfu/SAp, Orme des Merisiers, F-91191 Gif-sur-Yvette (France); Hughes, Annie [Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany); Indebetouw, Remy [Department of Astronomy, University of Virginia, and National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Israel, Frank P. [Sterrewacht Leiden, Leiden University, P.O. Box 9513, NL-2300 RA Leiden (Netherlands); Kawamura, Akiko [National Astronomical Observatory of Japan, Osawa, Mitaka, Tokyo, 181-8588 (Japan); and others

    2014-12-20

    The dust properties in the Large and Small Magellanic clouds (LMC/SMC) are studied using the HERITAGE Herschel Key Project photometric data in five bands from 100 to 500 μm. Three simple models of dust emission were fit to the observations: a single temperature blackbody modified by a power-law emissivity (SMBB), a single temperature blackbody modified by a broken power-law emissivity (BEMBB), and two blackbodies with different temperatures, both modified by the same power-law emissivity (TTMBB). Using these models, we investigate the origin of the submillimeter excess, defined as the submillimeter emission above that expected from SMBB models fit to observations <200 μm. We find that the BEMBB model produces the lowest fit residuals with pixel-averaged 500 μm submillimeter excesses of 27% and 43% for the LMC and SMC, respectively. Adopting gas masses from previous works, the gas-to-dust ratios calculated from our fitting results show that the TTMBB fits require significantly more dust than are available even if all the metals present in the interstellar medium (ISM) were condensed into dust. This indicates that the submillimeter excess is more likely to be due to emissivity variations than a second population of colder dust. We derive integrated dust masses of (7.3 ± 1.7) × 10{sup 5} and (8.3 ± 2.1) × 10{sup 4} M {sub ☉} for the LMC and SMC, respectively. We find significant correlations between the submillimeter excess and other dust properties; further work is needed to determine the relative contributions of fitting noise and ISM physics to the correlations.

  4. Dust and Gas in the Magellanic Clouds from the Heritage Herschel Key Project. I. Dust Properties and Insights into the Origin of the Submm (Submillimeter) Excess Emission

    Science.gov (United States)

    Gordon, Karl D.; Roman-Duval, Julia; Bot, Caroline; Meixner, Margaret; Babler, Brian; Bernard, Jean-Philippe; Bolatto, Alberto; Boyer, Martha L.; Clayton, Geoffrey C.; Engelbracht, Charles; hide

    2014-01-01

    The dust properties in the Large and Small Magellanic Clouds are studied using the HERITAGE Herschel Key Project photometric data in five bands from 100 to 500 micromillimeters. Three simple models of dust emission were fit to the observations: a single temperature blackbody modified by a powerlaw emissivity (SMBB), a single temperature blackbody modified by a broken power-law emissivity (BEMBB), and two blackbodies with different temperatures, both modified by the same power-law emissivity (TTMBB). Using these models we investigate the origin of the submillimeter excess; defined as the submillimeter (submm) emission above that expected from SMBB models fit to observations < 200 micromillimeters. We find that the BEMBB model produces the lowest fit residuals with pixel-averaged 500 micromillimeters submillimeter excesses of 27% and 43% for the Large and Small Magellanic Clouds, respectively. Adopting gas masses from previous works, the gas-to-dust ratios calculated from our fitting results show that the TTMBB fits require significantly more dust than are available even if all the metals present in the interstellar medium (ISM) were condensed into dust. This indicates that the submillimeter excess is more likely to be due to emissivity variations than a second population of colder dust. We derive integrated dust masses of (7.3 plus or minus 1.7) x 10 (sup 5) and (8.3 plus or minus 2.1) x 10 (sup 4) solar masses for the Large and Small Magellanic Clouds, respectively. We find significant correlations between the submillimeter excess and other dust properties; further work is needed to determine the relative contributions of fitting noise and ISM physics to the correlations.

  5. EXPLORING THE RELATION BETWEEN (SUB-)MILLIMETER RADIATION AND {gamma}-RAY EMISSION IN BLAZARS WITH PLANCK AND FERMI

    Energy Technology Data Exchange (ETDEWEB)

    Leon-Tavares, J.; Tornikoski, M.; Laehteenmaeki, A. [Aalto University Metsaehovi Radio Observatory, Metsaehovintie 114, FIN-02540 Kylmaelae (Finland); Valtaoja, E. [Tuorla Observatory, Department of Physics and Astronomy, University of Turku, 20100 Turku (Finland); Giommi, P.; Polenta, G.; Gasparrini, D.; Cutini, S., E-mail: leon@kurp.hut.fi [ASI Science Data Center, ASDC c/o ESRIN, via G. Galilei, 00044 Frascati (Italy)

    2012-07-20

    The coexistence of Planck and Fermi satellites in orbit has enabled the exploration of the connection between the (sub-)millimeter and {gamma}-ray emission in a large sample of blazars. We find that the {gamma}-ray emission and the (sub-)mm luminosities are correlated over five orders of magnitude, L{sub {gamma}}{proportional_to}L{sub (sub-)mm}. However, this correlation is not significant at some frequency bands when simultaneous observations are considered. The most significant statistical correlations, on the other hand, arise when observations are quasi-simultaneous within two months. Moreover, we find that sources with an approximate spectral turnover in the middle of the mm-wave regime are more likely to be strong {gamma}-ray emitters. These results suggest a physical relation between the newly injected plasma components in the jet and the high levels of {gamma}-ray emission.

  6. Hacking for astronomy: can 3D printers and open-hardware enable low-cost sub-/millimeter instrumentation?

    Science.gov (United States)

    Ferkinhoff, Carl

    2014-07-01

    There have been several exciting developments in the technologies commonly used n in the hardware hacking community. Advances in low cost additive-manufacturing processes (i.e. 3D-printers) and the development of openhardware projects, which have produced inexpensive and easily programmable micro-controllers and micro-computers (i.e. Arduino and Raspberry Pi) have opened a new door for individuals seeking to make their own devices. Here we describe the potential for these technologies to reduce costs in construction and development of submillimeter/millimeter astronomical instrumentation. Specifically we have begun a program to measure the optical properties of the custom plastics used in 3D-printers as well as the printer accuracy and resolution to assess the feasibility of directly printing sub- /millimeter transmissive optics. We will also discuss low cost designs for cryogenic temperature measurement and control utilizing Arduino and Raspberry Pi.

  7. Millimeter and Submillimeter Observations of Comet 67P's Nucleus, Gas, and Dust with the Rosetta/MIRO Instrument

    Science.gov (United States)

    Hofstadter, Mark

    2016-04-01

    The Microwave Instrument for the Rosetta Orbiter (MIRO) has been making measurements of comet 67P/C-G since June 2014, when the comet was 3.92 AU from the Sun and Rosetta was approximately 400,000 km from the nucleus. Those first observations were spatially unresolved measurements of the 556 GHz water line, used to infer the abundance and velocity of water vapor in the coma (Gulkis et al. 2015, Science 347). In the almost two years since that time, as the spacecraft has moved closer to the nucleus and the comet has become more active (perihelion at 1.2 AU from the Sun occurred in August 2015), MIRO's submillimeter spectrometer (working at frequencies near 550 GHz, or wavelengths near 0.5 mm) has been used to determine the velocity, abundance, and spatial distribution of H216O, H217O, H218O, CH3OH, NH3, and CO in the coma as a function of time (e.g. water is discussed by Biver et al. 2015 and Lee et al. 2015, Astron. and Astrophys. 583). In addition to its submillimeter spectrometer, MIRO has two broad band continuum channels operating at wavelengths near 0.5 and 1.6 millimeter. These channels are designed to probe the nucleus ˜1 millimeter to 10 cm below the surface. Data have been used to infer properties such as thermal inertia, porosity, and ice content as functions of location, depth, and time (e.g. Schloerb et al. 2015 and Choukroun et al. 2015, Astron. and Astrophys. 583). These channels have also been used to map the distribution of relatively large dust grains (radius > ˜1 mm) in the inner coma of the comet, with the potential to constrain models of dust acceleration, cooling, and fragmentation. This talk will review the latest results from MIRO's measurements of the nucleus, coma, and dust, and discuss some of the processes that couple these components of the comet.

  8. The JCMT Transient Survey: Identifying Submillimeter Continuum Variability over Several Year Timescales Using Archival JCMT Gould Belt Survey Observations

    Science.gov (United States)

    Mairs, Steve; Johnstone, Doug; Kirk, Helen; Lane, James; Bell, Graham S.; Graves, Sarah; Herczeg, Gregory J.; Scicluna, Peter; Bower, Geoffrey C.; Chen, Huei-Ru Vivien; Hatchell, Jennifer; Aikawa, Yuri; Chen, Wen-Ping; Kang, Miju; Kang, Sung-Ju; Lee, Jeong-Eun; Morata, Oscar; Pon, Andy; Scholz, Aleks; Takahashi, Satoko; Yoo, Hyunju; The JCMT Transient Team

    2017-11-01

    Investigating variability at the earliest stages of low-mass star formation is fundamental in understanding how a protostar assembles mass. While many simulations of protostellar disks predict non-steady accretion onto protostars, deeper investigation requires robust observational constraints on the frequency and amplitude of variability events characterized across the observable SED. In this study, we develop methods to robustly analyze repeated observations of an area of the sky for submillimeter variability in order to determine constraints on the magnitude and frequency of deeply embedded protostars. We compare 850 μm JCMT Transient Survey data with archival JCMT Gould Belt Survey data to investigate variability over 2-4 year timescales. Out of 175 bright, independent emission sources identified in the overlapping fields, we find seven variable candidates, five of which we classify as Strong, and the remaining two we classify as Extended to indicate that the latter are associated with larger-scale structure. For the Strong variable candidates, we find an average fractional peak brightness change per year of | 4.0| % {{yr}}-1, with a standard deviation of 2.7 % {{yr}}-1. In total, 7% of the protostars associated with 850 μm emission in our sample show signs of variability. Four of the five Strong sources are associated with a known protostar. The remaining source is a good follow-up target for an object that is anticipated to contain an enshrouded, deeply embedded protostar. In addition, we estimate the 850 μm periodicity of the submillimeter variable source, EC 53, to be 567 ± 32 days, based on the archival Gould Belt Survey data.

  9. Tracking antenna architectures based on an integrated mixer microstrip patch array

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Sanjeev

    1997-07-01

    The object of this work is to design, develop and characterize both theoretically and experimentally a compact integrated mixer microstrip patch antenna which exhibits a low level of cross-polarization. Modelling of this antenna using various CAD techniques and supporting measurements has led to a clearer understanding of its operation and the optimization of its design. The attractiveness of such a frequency scaleable design lies in the inherent simplicity and ease with which it can be used to produce an intermediate frequency (IF) signal with minimum circuit complexity and low cross-polar levels. The operation of the integrated mixer antenna circuit is exploited under the phenomenon of injection locking for its potential for direct phase modulation and detection. It leads to new vistas of study such as IF phase-shifterless beam steering. Here the desired phased shift is derived through injection locking and achieved solely by the DC bias control, thus eliminating the need for phase shifters and feed networks. A self-tracking integrated mixer array has also been described which uses an in-band pilot carrier signal for self-calibration. By minor alteration of the integrated antenna topology, a minimum complexity variant of a heterodyne retrodirective array has then been realized. These tracking antenna architectures minimize the problems of cost, complexity and size limitations associated with conventional phased arrays. These are designed for emerging commercial applications and are resolutions of some trade-offs that balance performance, cost and reliability. Theoretical and experimental results are presented to show their performances and, in addition, the practical requirements relevant to these are also addressed. The results indicate that these tracking antenna architectures based on an integrated mixer microstrip patch array could form a synergistic link with other emerging technologies and can be to some extent embodied in future phased array designs

  10. Directivity of Antenna Arrays

    Science.gov (United States)

    Bulgakova, A. A.; Gorobets, N. N.; Katrich, V. A.; Lyashchenko, V. A.

    2016-12-01

    Purpose: Theoretical investigation of directive gains of linear and planar antenna arrays depending on the distance between radiators and wavelength. Design/methodology/approach: Computing methods in applied mathematics in MathCad were used to calculate the twofold integrals of the radiation pattern over power throughout the whole space observed, defining the directivity in the most general terms. Patterns of radiators, i. e. elements of antenna arrays, are specified by mathematical models. The calculation accounts for the subintegral fast oscillating function. Findings: Calculations and analysis of a directive gain according to the number of radiators and distances between them in fractions of wavelength are made. It is shown that at the ratio of distance between radiators to wave-length being d/λ =0.5 the directivity of array of isotropic radiators is 1.5N², N - number of radiators. When increasing the d/λ to 0.65÷0.97 the directivity increases according to the law close to the linear one up to the maximum possible value for the specified number of radiators. With the increase of d/λ to the values greater than one, the directivity is significantly reduced (the “blinding” effect of non-phased antenna arrays) and its dependence with the growth of d/λ is decaying and oscillating in character. By that, the transfer function of antenna arrays has some vital difference from the transfer function of continuous antennas. Conclusions: Antenna arrays distort the waveform and spectrum of radiated and received signals as a result of irregular changes of their directivity depending on wavelength. The detected “blinding” effect of non-phased antenna arrays of large electrical dimensions must be taken into account in wideband and superwideband radio-electronics systems, especially in radio astronomy, telecommunications systems and superwideband radar.

  11. Indium Hybridization of Large Format TES Bolometer Arrays to Readout Multiplexers for Far-Infrared Astronomy

    Science.gov (United States)

    Miller, Timothy M.; Costen, Nick; Allen, Christine

    2007-01-01

    The advance of new detector technologies combined with enhanced fabrication methods has resulted in an increase in development of large format arrays. The next generation of scientific instruments will utilize detectors containing hundreds to thousands of elements providing a more efficient means to conduct large area sky surveys. Some notable detectors include a 32x32 x-ray microcalorimeter for Constellation-X, an infrared bolometer called SAFIRE to fly on the airborne observatory SOFIA, and the sub-millimeter bolometer SCUBA-2 to be deployed at the JCMT which will use more than 10,000 elements for two colors, each color using four 32x40 arrays. Of these detectors, SCUBA-2 is farthest along in development and uses indium hybridization to multiplexers for readout of the large number of elements, a technology that will be required to enable the next generation of large format arrays. Our current efforts in working toward large format arrays have produced GISMO, the Goddard IRAM Superconducting 2-Millimeter observer. GISMO is a far infrared instrument to be field tested later this year at the IRAM 30 meter telescope in Spain. GISMO utilizes transition edge sensor (TES) technology in an 8x16 filled array format that allows for typical fan-out wiring and wire-bonding to four 1x32 NIST multiplexers. GISMO'S electrical wiring is routed along the tops of 30 micron walls which also serve as the mechanical framework for the array. This architecture works well for the 128 element array, but is approaching the limit for routing the necessary wires along the surface while maintaining a high fill factor. Larger format arrays will benefit greatly from making electrical connections through the wafer to the backside, where they can be hybridized to a read-out substrate tailored to handling the wiring scheme. The next generation array we are developing is a 32x40 element array on a pitch of 1135 microns that conforms to the NIST multiplexer, already developed for the SCUBA-2

  12. Developments in Miniaturized Laser Heterodyne Radiometer (mini-LHR) construction for groundtruth measurements of CH4 and CO2 in harsh terrain

    Science.gov (United States)

    DiGregorio, A.; Wilson, E. L.; Hoffman, C.; Grunberg, C.; Mao, J.; Ramanathan, A. K.

    2016-12-01

    We present an updated, ruggedized design of NASA Goddard Space Flight Center's Miniaturized Laser Heterodyne Radiometer (mini-LHR), and the results of testing in the Bonanza Creek Research Forest. The mini-LHR is a passive variation of typical heterodyne radiometry instruments, designed to work in tandem with the AERONET sun photometer for collection of column methane (CH4) and carbon dioxide (CO2) in harsh environments. Advancements in the development of the Cube-Sat version of the mini-LHR have allowed a more than 50% reduction in size, weight, and power usage of the mini-LHR. Now small enough to fit in a medium handbag, the mini-LHR can be run off of a small 35 Watt solar panel and backup battery for continuous measurement. Using a touch-screen control interface built off of a Raspberry Pi, the updated mini-LHR is capable of data collection and preliminary data processing, even without internet, cellular, or satellite connectivity. The improvements made to the mini-LHR were tested in a field campaign in May 2016 funded under NASA's IDS program to track CH4 and CO2 emissions above thawing permafrost. In addition to being a comprehensive study of methane release from thawing permafrost, this pilot study tested the ruggedization and functionality of the instrument in three different environments- a black spruce forest, collapsed scar bog, and fen.

  13. Performance Analysis of Heterodyne-Detected OCDMA Systems Using PolSK Modulation over a Free-Space Optical Turbulence Channel

    Directory of Open Access Journals (Sweden)

    Fan Bai

    2015-10-01

    Full Text Available This paper presents a novel model of heterodyne-detected optical code-division multiple-access (OCDMA systems employing polarization shift keying (PolSK modulation over a free-space optical (FSO turbulence channel. In this article, a new transceiver configuration and detailed analytical model for the proposed system are provided and discussed, taking into consideration the potential of heterodyne detection on mitigating the impact of turbulence-induced irradiance fluctuation on the performance of the proposed system under the gamma-gamma turbulence channel. Furthermore, we derived the closed-form expressions for the system error probability and outage probability, respectively. We determine the advantages of the proposed modeling by performing a comparison with a direct detection scheme obtained from an evaluation of link performance under the same environment conditions. The presented work also shows the most significant impact factor that degrades the performance of the proposed system and indicates that the proposed approach offers an optimum link performance compared to conventional cases.

  14. Efficient Array Design for Sonotherapy

    OpenAIRE

    Stephens, Douglas N.; Kruse, Dustin E.; Ergun, Arif S.; Barnes, Stephen; Ming Lu, X.; Ferrara, Katherine

    2008-01-01

    New linear multi-row, multi-frequency arrays have been designed, constructed and tested as fully operational ultrasound probes to produce confocal imaging and therapeutic acoustic intensities with a standard commercial ultrasound imaging system. The triple-array probes and imaging system produce high quality B-mode images with a center row imaging array at 5.3 MHz, and sufficient acoustic power with dual therapeutic arrays to produce mild hyperthermia at 1.54 MHz. The therapeutic array pair i...

  15. A compact ground-based laser heterodyne radiometer for global column measurements of CO2 and CH4

    Science.gov (United States)

    Steel, Emily; Clarke, Gregory; Ramanathan, Anand; Mao, Jianping; Ott, Lesley; Duncan, Bryan; Melroy, Hilary; McLinden, Matthew; Holben, Brent; Houston Miller, J.

    2015-04-01

    Implementing effective global strategies to understand climate change is hindered by a lack of understanding of both anthropogenic emissions and land and ocean carbon reservoirs. Though in situ surface measurements and satellites provide valuable information for estimating carbon fluxes, areas not well covered by current observing systems (e.g. high latitude regions, tropical forests and wetlands) remain poorly understood. Deficiencies in understanding the processes governing carbon flux introduce considerable uncertainty to predictions of climate change over the coming century. Our vision is to enhance worldwide carbon monitoring by developing a low-cost ground network of miniaturized laser heterodyne radiometer (Mini-LHR) instruments that measure CO2 and CH4 in the atmospheric column. Ground-based remote sensing has the potential to fill gaps in the satellite data record while providing a complementary long-term observational record. This uninterrupted data record, would both bridge gaps in data sets and offer validation for key flight missions such as OCO-2, OCO-3 and ASCENDS. Mini-LHR instruments will be deployed as an accompaniment to AERONET. In addition to the complementary aerosol optical depth measurement, tandem operation with AERONET provides a clear pathway for the Mini-LHR to be expanded into a global monitoring network. AERONET has more than 500 instruments worldwide offering coverage in key arctic regions (not covered by OCO-2) where accelerated warming due to the release of CO2 and CH4 from thawing tundra and permafrost is a concern. Mini-LHR instruments at AERONET locations could also greatly improve data coverage in regions with large flux uncertainties such as North America and Western Europe, and under-sampled areas such as South America and Asia. Currently, the only ground global network that routinely measures multiple greenhouse gases in the atmospheric column is TCCON with 18 operational sites worldwide and two in the US. Cost and size of

  16. Phased array imaging

    Science.gov (United States)

    1990-09-01

    The problem of recoverable image resolution is investigated for the case where an imaging array is used which array has an optical transfer function that may be described as consisting of islands of nonzero value in a sea of zero values. Can the missing spatial frequency information can be provided--can, in effect, a form of (interpolative) super resolution. The CLEAN algorithm used by radio astronomers suggests that this should be possible. The results developed here indicate that this can be done, with no significant price in terms of signal-to-noise ratio to be paid, and further show that a nonlinear algorithm, like CLEAN, is not required. The results show that the feasibility of doing this depends on the angular size of the object being imaged. We find that its size must be less than the inverse of the largest gap between islands in the array's optical transfer function.

  17. Photovoltaic array performance model.

    Energy Technology Data Exchange (ETDEWEB)

    Kratochvil, Jay A.; Boyson, William Earl; King, David L.

    2004-08-01

    This document summarizes the equations and applications associated with the photovoltaic array performance model developed at Sandia National Laboratories over the last twelve years. Electrical, thermal, and optical characteristics for photovoltaic modules are included in the model, and the model is designed to use hourly solar resource and meteorological data. The versatility and accuracy of the model has been validated for flat-plate modules (all technologies) and for concentrator modules, as well as for large arrays of modules. Applications include system design and sizing, 'translation' of field performance measurements to standard reporting conditions, system performance optimization, and real-time comparison of measured versus expected system performance.

  18. Solar array welding developement

    Science.gov (United States)

    Elms, R. V., Jr.

    1974-01-01

    The present work describes parallel gap welding as used for joining solar cells to the cell interconnect system. Sample preparation, weldable cell parameter evaluation, bond scheduling, bond strength evaluation, and bonding and thermal shock tests are described. A range of weld schedule parameters - voltage, time, and force - can be identified for various cell/interconnect designs that will provide adequate bond strengths and acceptably small electrical degradation. Automation of solar array welding operations to a significant degree has been achieved in Europe and will be receiving increased attention in the U.S. to reduce solar array fabrication costs.

  19. Dynamic scheduling and planning parallel observations on large Radio Telescope Arrays with the Square Kilometre Array in mind

    Science.gov (United States)

    Buchner, Johannes

    2011-12-01

    literature: The inability of a GA to properly improve schedules and the generation of schedules with frequent interruptions. Finally, we demonstrate the scheduling framework for several operating telescopes: (1) Dynamic re-scheduling with the AUT Warkworth 12m telescope, (2) Scheduling for the Australian Mopra 22m telescope and scheduling for the Allen Telescope Array. Furthermore, we discuss the applicability of the presented scheduling framework to the Atacama Large Millimeter/submillimeter Array (ALMA, in construction) and the SKA. In particular, during the development phase of the SKA, this dynamic, scalable scheduling framework can accommodate changing conditions.

  20. Diffraction aperture non-ideal behaviour of air coupled transducers array elements designed for NDT.

    Science.gov (United States)

    Prego Borges, J L; Montero de Espinosa, F; Salazar, J; Garcia-Alvarez, J; Chávez, J A; Turó, A; Garcia-Hernandez, M J

    2006-12-22

    Air coupled piezoelectric ultrasonic array transducers are a novel tool that could lead to interesting advances in the area of non-contact laminar material testing using Lamb wave's propagation techniques. A key issue on the development of such transducers is their efficient coupling to air media (impedance mismatch between the piezoelectric material and air is 90 dB or more). Adaptation layers are used in order to attain good matching and avoid possible serious signal degradation. However, the introduction of these matching layers modify the transducer surface behaviour and, consequently, radiation characteristics are altered, making the usual idealization criteria (of uniform surface movement) adopted for field simulation purposes inaccurate. In our system, we have a concave linear-array transducer of 64 elements (electrically coupled by pairs) working at 0.8 MHz made of PZ27 rectangular piezoceramics (15 mm x 0.3 mm) with two matching layers made of polyurethane and porous cellulose bonded on them. Experimental measurements of the acoustic aperture of single excited array elements have shown an increment on the geometrical dimensions of its active surface. A sub-millimeter vibrometer laser scan has revealed an extension of the aperture beyond the supposed physical single array element dimensions. Non-uniform symmetric apodized velocity surface vibration amplitude profile with a concave delay contour indicates the presumed existence of travelling wave phenomena over the surface of the outer array matching layer. Also, asymptotic propagation velocities around 2500 m/s and attenuation coefficient between 15 and 20 dB/mm has been determined for the travelling waves showing clear tendencies. Further comparisons between the experimental measurements of single array element field radiation diagram and simulated equivalent aperture counterpart reveal good agreement versus the ideal (uniform displaced) rectangular aperture. For this purpose an Impulse Response Method

  1. Array Theory and Nial

    DEFF Research Database (Denmark)

    Falster, Peter; Jenkins, Michael

    1999-01-01

    This report is the result of collaboration between the authors during the first 8 months of 1999 when M. Jenkins was visiting professor at DTU. The report documents the development of a tool for the investigation of array theory concepts and in particular presents various approaches to choose...

  2. TANGO Array. 2. Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Bauleo, P. E-mail: pablo.bauleo@colostate.edu; Bonifazi, C.; Filevich, A

    2004-01-11

    The angular and energy resolutions of the TANGO Array were obtained using extensive Monte Carlo simulations performed with a double purpose: (1) to determine the appropriate parameters for the array fitting to the desired range of sensitivity (the knee energy region), and (2) to construct a reliable shower database required for reference in the analysis of experimental data. The AIRES code, with the SIBYLL hadronic collision package, was used to simulate Extended Air Showers produced by primary cosmic rays (assuming protons and iron nuclei), with energies ranging from 10{sup 14} to 10{sup 18} eV. These data were fed into a realistic code which simulates the response of the detectors (water Cherenkov detectors), including the electronics, pickup noise, and the signal attenuation in the connecting cables. The trigger stage was considered in the simulations in order to estimate the trigger efficiency of the array and to verify the accuracy of the reconstruction codes. This paper delineates the simulations performed to obtain the expected behavior of the array, and describes the simulated data. The results of these simulations suggest that we can expect an error in the energy of the primary cosmic-ray of {approx}60% of the estimated value and that the error in the measurement of the direction of arrival can be estimated as {approx}4 deg. . The present simulations also indicate that unambiguous assignments of the primary energy cannot be obtained because of the uncertainty in the nature of the primary cosmic ray.

  3. TANGO Array.. 2. Simulations

    Science.gov (United States)

    Bauleo, P.; Bonifazi, C.; Filevich, A.

    2004-01-01

    The angular and energy resolutions of the TANGO Array were obtained using extensive Monte Carlo simulations performed with a double purpose: (1) to determine the appropriate parameters for the array fitting to the desired range of sensitivity (the knee energy region), and (2) to construct a reliable shower database required for reference in the analysis of experimental data. The AIRES code, with the SIBYLL hadronic collision package, was used to simulate Extended Air Showers produced by primary cosmic rays (assuming protons and iron nuclei), with energies ranging from 10 14 to 10 18 eV. These data were fed into a realistic code which simulates the response of the detectors (water Cherenkov detectors), including the electronics, pickup noise, and the signal attenuation in the connecting cables. The trigger stage was considered in the simulations in order to estimate the trigger efficiency of the array and to verify the accuracy of the reconstruction codes. This paper delineates the simulations performed to obtain the expected behavior of the array, and describes the simulated data. The results of these simulations suggest that we can expect an error in the energy of the primary cosmic-ray of ˜60% of the estimated value and that the error in the measurement of the direction of arrival can be estimated as ˜4°. The present simulations also indicate that unambiguous assignments of the primary energy cannot be obtained because of the uncertainty in the nature of the primary cosmic ray.

  4. Array processors in chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Ostlund, N.S.

    1980-01-01

    The field of attached scientific processors (''array processors'') is surveyed, and an attempt is made to indicate their present and possible future use in computational chemistry. The current commercial products from Floating Point Systems, Inc., Datawest Corporation, and CSP, Inc. are discussed.

  5. Laboratory permittivity measurements of icy planetary analogs in the millimeter and submillimeter domains, in relation with JUICE mission.

    Science.gov (United States)

    Brouet, Y.; Jacob, K.; Murk, A.; Poch, O.; Pommerol, A.; Thomas, N.; Levasseur-Regourd, A. C.

    2015-12-01

    The European Space Agency's JUpiter ICy moons Explorer (JUICE) spacecraft is planned for launch in 2022 and arrival at Jupiter in 2030. It will observe the planet Jupiter and three of its largest moons, Ganymede, Callisto and Europa. One instrument on the JUICE spacecraft is the Sub-millimeter Wave Instrument (SWI), which will measure brightness temperatures from Jupiter's stratosphere and troposphere, and from subsurfaces of Jupiter's icy moons. In the baseline configuration SWI consists of two tunable sub-millimeter wave receivers operating from 530 to 625 GHz. As an alternative one of the receivers could cover the range of 1080 and 1275 GHz. Inversion models are strongly dependent on the knowledge of the complex relative permittivity (hereafter permittivity) of the target material to retrieve the physical properties of the subsurface (e.g. [1][2]). We set up a laboratory experiment allowing us to perform reproducible measurements of the complex scattering parameters S11 and S21 in the ranges of 70 to 110 GHz, of 100 to 160 GHz, of 140 to 220 GHz, of 140 to 220 GHz and of 510 to 715 GHz. These scattering parameters can be used to retrieve the permittivity of icy analogs of the surfaces and subsurfaces of Jupiter's icy moons in order to prepare the data interpretation of SWI [3]. The measurements are performed under laboratory conditions with a quasi-optical bench (Institute of Applied Physics, University of Bern). The icy analogs that we prepare in the Laboratory for Outflow Studies of Sublimating Materials (LOSSy, Physics Institute, University of Bern), include two different porous water ice samples composed of fine-grained ice particles with a size range of 4 to 6 microns and ice particles with a size range of 50 to 100 microns [4][5]; and possibly CO2 ice. We will present the general experimental set-up and the first results in the context to prepare the data interpretation of SWI. [1] Ulaby, F. T., Long, D. G., 2014. Microwave radar and radiometric remote

  6. RoboWeedSupport-Semi-Automated Unmanned Aerial System for Cost Efficient High Resolution in Sub-Millimeter Scale Acquisition of Weed Images

    OpenAIRE

    Simon L. Madsen; Mads Dyrmann; Morten S. Laursen; Rasmus N. Jørgensen

    2017-01-01

    Recent advances in the Unmanned Aerial System (UAS) safety and perception systems enable safe low altitude autonomous terrain following flights recently demonstrated by the consumer DJI Mavic PRO and Phamtom 4 Pro drones. This paper presents the first prototype system utilizing this functionality in form of semi-automated UAS based collection of crop/weed images where the embedded perception system ensures a significantly safer and faster gathering of weed images with sub-millimeter resolutio...

  7. Submillimeter Observations of CLASH 2882 and the Evolution of Dust in this Galaxy

    Science.gov (United States)

    Dwek, Eli; Staguhn, Johannes; Arendt, Richard G; Kovacs, Attila; Decarli, Roberto; Egami, Eiichi; Michalowski, Michal J.; Rawle, Timothy D.; Toft, Sune; Walter, Fabian

    2015-01-01

    Two millimeter observations of the MACS J1149.6+2223 cluster have detected a source that was consistent with the location of the lensed MACS 1149-JD galaxy at z = 9.6. A positive identification would have rendered this galaxy as the youngest dust forming galaxy in the universe. Follow up observation with the AzTEC 1.1 mm camera and the IRAM NOrthern Extended Millimeter Array (NOEMA) at 1.3 mm have not confirmed this association. In this paper we show that the NOEMA observations associate the 2 mm source with [PCB2012] 2882,12 source number 2882 in the Cluster Lensing And Supernova survey with Hubble (CLASH) catalog of MACS J1149.6 +2223. This source, hereafter referred to as CLASH 2882, is a gravitationally lensed spiral galaxy at z = 0.99. We combine the Goddard IRAM Superconducting 2-Millimeter Observer (GISMO) 2 mm and NOEMA 1.3 mm fluxes with other (rest frame) UV to far-IR observations to construct the full spectral energy distribution of this galaxy, and derive its star formation history, and stellar and interstellar dust content. The current star formation rate of the galaxy is 54/mu/Solar Mass/yr, and its dust mass is about 5 × 10(exp 7)/mu Solar Mass, where mu is the lensing magnification factor for this source, which has a mean value of 2.7. The inferred dust mass is higher than the maximum dust mass that can be produced by core collapse supernovae and evolved AGB stars. As with many other star forming galaxies, most of the dust mass in CLASH 2882 must have been accreted in the dense phases of the interstellar medium.

  8. Characterization of multi-scale porous structure of fly ash/phosphate geopolymer hollow sphere structures: from submillimeter to nano-scale.

    Science.gov (United States)

    Li, Ruifeng; Wu, Gaohui; Jiang, Longtao; Sun, Dongli

    2015-01-01

    In the present work, the porous structure of fly ash/phosphate geopolymer hollow sphere structures (FPGHSS), prepared by pre-bonding and curing technology, has been characterized by multi-resolution methods from sub-millimeter to nano-scale. Micro-CT and confocal microscopy could provide the macroscopic distribution of porous structure on sub-millimeter scale, and hollow fly ashes with sphere shape and several sub-millimeter open cells with irregular shape were identified. SEM is more suitable to illustrate the distribution of micro-sized open and closed cells, and it was found that the open cells of FPGHSS were mainly formed in the interstitial porosity between fly ashes. Mercury porosimeter measurement showed that the micro-sized open cell of FPGHSS demonstrated a normal/bimodal distribution, and the peaks of pore size distribution were mainly around 100 and 10 μm. TEM observation revealed that the phosphate geopolymer was mainly composed of the porous area with nano-pores and dense areas, which were amorphous Al-O-P phase and α-Al2O3 respectively. The pore size of nano-pores demonstrated a quasi-normal distribution from about 10 to 100 nm. Therefore, detailed information of the porous structure of FPGHSS could be revealed using multiple methods. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Concurrent array-based queue

    Science.gov (United States)

    Heidelberger, Philip; Steinmacher-Burow, Burkhard

    2015-01-06

    According to one embodiment, a method for implementing an array-based queue in memory of a memory system that includes a controller includes configuring, in the memory, metadata of the array-based queue. The configuring comprises defining, in metadata, an array start location in the memory for the array-based queue, defining, in the metadata, an array size for the array-based queue, defining, in the metadata, a queue top for the array-based queue and defining, in the metadata, a queue bottom for the array-based queue. The method also includes the controller serving a request for an operation on the queue, the request providing the location in the memory of the metadata of the queue.

  10. Radar techniques using array antennas

    CERN Document Server

    Wirth, Wulf-Dieter

    2013-01-01

    Radar Techniques Using Array Antennas is a thorough introduction to the possibilities of radar technology based on electronic steerable and active array antennas. Topics covered include array signal processing, array calibration, adaptive digital beamforming, adaptive monopulse, superresolution, pulse compression, sequential detection, target detection with long pulse series, space-time adaptive processing (STAP), moving target detection using synthetic aperture radar (SAR), target imaging, energy management and system parameter relations. The discussed methods are confirmed by simulation stud

  11. Micro-Spec: An Ultra-Compact, High-Sensitivity Spectrometer for Far-Infrared and Sub-Millimeter Astronomy

    Science.gov (United States)

    Cataldo, Giuseppe; Hsieh, Wen-Ting; Huang, Wei-Chung; Moseley, S. Harvey; Stevenson, Thomas R.; Wollack, Edward J.

    2013-01-01

    High-performance, integrated spectrometers operating in the far-infrared and sub-millimeter promise to be powerful tools for the exploration of the epochs of reionization and initial galaxy formation. These devices, using high-efficiency superconducting transmission lines, can achieve the performance of a meter-scale grating spectrometer in an instrument implemented on a four-inch silicon wafer. Such a device, when combined with a cryogenic telescope in space, provides an enabling capability for studies of the early universe. Here, the optical design process for Micro-Spec (mu-Spec) is presented, with particular attention given to its two-dimensional diffractive region, where the light of different wavelengths is focused on the different detectors. The method is based on the stigmatization and minimization of the light path function in this bounded region, which results in an optimized geometrical configuration. A point design with an efficiency of approx. 90% has been developed for initial demonstration, and can serve as the basis for future instruments. Design variations on this implementation are also discussed, which can lead to lower efficiencies due to diffractive losses in the multimode region.

  12. Determining the Concentrations and Temperatures of Products in a CF_4/CHF_3/N_2 Plasma via Submillimeter Absorption Spectroscopy

    Science.gov (United States)

    Helal, Yaser H.; Neese, Christopher F.; De Lucia, Frank C.; Ewing, Paul R.; Agarwal, Ankur; Craver, Barry; Stout, Phillip J.; Armacost, Michael D.

    2017-06-01

    Plasmas used for the manufacturing of semiconductor devices are similar in pressure and temperature to those used in the laboratory for the study of astrophysical species in the submillimeter (SMM) spectral region. The methods and technology developed in the SMM for these laboratory studies are directly applicable for diagnostic measurements in the semiconductor manufacturing industry. Many of the molecular neutrals, radicals, and ions present in processing plasmas have been studied and their spectra have been cataloged or are in the literature. In this work, a continuous wave, intensity calibrated SMM absorption spectrometer was developed as a remote sensor of gas and plasma species. A major advantage of intensity calibrated rotational absorption spectroscopy is its ability to determine absolute concentrations and temperatures of plasma species from first principles without altering the plasma environment. An important part of this work was the design of the optical components which couple 500-750 GHz radiation through a commercial inductively coupled plasma chamber. The measurement of transmission spectra was simultaneously fit for background and absorption signal. The measured absorption was used to calculate absolute densities and temperatures of polar species. Measurements for CHF_3, CF_2, FCN, HCN, and CN made in a CF_4/CHF_3/N_2 plasma will be presented. Temperature equilibrium among species will be shown and the common temperature is leveraged to obtain accurate density measurements for simultaneously observed species. The densities and temperatures of plasma species are studied as a function of plasma parameters, including flow rate, pressure, and discharge power.

  13. Fibrosis and Atrial Fibrillation: Computerized and Optical Mapping; A View into the Human Atria at Submillimeter Resolution.

    Science.gov (United States)

    Hansen, Brian J; Zhao, Jichao; Fedorov, Vadim V

    2017-06-01

    Recent studies strongly suggest that the majority of atrial fibrillation (AF) patients with diagnosed or subclinical cardiac diseases have established or even pre-existing fibrotic structural remodeling, which may lead to conduction abnormalities and reentrant activity that sustain AF. As conventional treatments fail to treat AF in far too many cases, an urgent need exists to identify specific structural arrhythmogenic fibrosis patterns, which may maintain AF, in order to identify effective ablation targets for AF treatment. However, the existing challenge is to define what exact structural remodeling within the complex 3D human atrial wall is arrhythmogenic, as well as linking arrhythmogenic fibrosis to an underlying mechanism of AF maintenance in the clinical setting. This review is focused on the role of 3D fibrosis architecture in the mechanisms of AF maintenance revealed by submillimeter, high-resolution ex-vivo imaging modalities directly of human atria, as well as from in-silico 3D computational techniques that can be able to overcome in-vivo clinical limitations. The systematic integration of functional and structural imaging ex-vivo may inform the necessary integration of electrode and structural mapping in-vivo. A holistic view of AF driver mechanisms may begin to identify the defining characteristics or "fingerprints" of reentrant AF drivers, such as 3D fibrotic architecture, in order to design optimal patient-specific ablation strategies.

  14. Submillimeter wave GaAs Schottky diode application based study and optimization for 0.1-1.5 THz

    Science.gov (United States)

    Jenabi, Sarvenaz; Malekabadi, Ali; Deslandes, Dominic; Boone, Francois; Charlebois, Serge A.

    2017-08-01

    In this paper, a design and optimization method for submillimeter-wave Schottky diode is proposed. Parasitic capacitance is significantly reduced to under 20% of the total capacitance of the diode. The parasitic capacitance value is measured to be 0.6 fF for 1 μm anode radius which increased the cut-off frequency to 1.5 THz. A corresponding microfabrication process that provides higher degrees of freedom for the anode diameter, air-bridge dimensions and distance to the substrate is introduced and implemented. The DC and RF measurements are provided and compared with the simulations. In order to provide a better understanding of the diode behavior, the limiting factors of the cut-off frequency for different applications are studied and compared. For the mixer/multiplier mode, an improved and expanded formulation for calculation of the cut-off frequency is introduced. It is shown that the usable voltage bias range (with acceptable cut-off frequency) is limited by the exponential reduction of junction resistance, Rj , in mixer/multiplier mode.

  15. Timing jitter characterization of mode-locked lasers with <1 zs/√Hz resolution using a simple optical heterodyne technique.

    Science.gov (United States)

    Hou, D; Lee, C-C; Yang, Z; Schibli, T R

    2015-07-01

    Timing jitter characterization of free-running mode-locked lasers with an unprecedented resolution is demonstrated using an optical heterodyne technique. A highly sensitive timing jitter phase-discrimination signal with low-parasitic-amplitude sensitivity is achieved. Analytical and numerical methods are used to analyze the properties of the discrimination signal. For an experimental demonstration, we measure the timing jitter between two loosely synchronized mode-locked Er:Yb:glass lasers with 500-MHz fundamental repetition rates. The timing jitter-detection noise floor for a single mode-locked laser reaches 2.8×10(-13)  fs(2)/Hz (∼530  ys/√Hz), and the integrated timing jitter is 16.3 as from 10 kHz to the Nyquist frequency (250 MHz). These results show that this approach can be a simpler alternative to the well-established balanced optical cross-correlation technique.

  16. A 4 U Laser Heterodyne Radiometer for Methane (CH4) and Carbon Dioxide (CO2) Measurements from an Occultation-Viewing CubSat

    Science.gov (United States)

    Wilson, Emily L.; DiGregorio, A. J.; Riot, Vincent J.; Ammons, Mark S.; Bruner, WIlliam W.; Carter, Darrell; Mao, Jianping; Ramanathan, Anand; Strahan, Susan E.; Oman, Luke D.; hide

    2017-01-01

    We present a design for a 4 U (20 cm 20 cm 10 cm) occultation-viewing laser heterodyne radiometer (LHR) that measures methane (CH4), carbon dioxide (CO2) and water vapor(H2O) in the limb that is designed for deployment on a 6 U CubeSat. The LHR design collects sunlight that has undergone absorption by the trace gas and mixes it with a distributive feedback (DFB) laser centered at 1640 nm that scans across CO2, CH4, and H2O absorption features. Upper troposphere lower stratosphere measurements of these gases provide key inputs to stratospheric circulation models: measuring stratospheric circulation and its variability is essential for projecting how climate change will affect stratospheric ozone.

  17. Timed arrays wideband and time varying antenna arrays

    CERN Document Server

    Haupt, Randy L

    2015-01-01

    Introduces timed arrays and design approaches to meet the new high performance standards The author concentrates on any aspect of an antenna array that must be viewed from a time perspective. The first chapters briefly introduce antenna arrays and explain the difference between phased and timed arrays. Since timed arrays are designed for realistic time-varying signals and scenarios, the book also reviews wideband signals, baseband and passband RF signals, polarization and signal bandwidth. Other topics covered include time domain, mutual coupling, wideband elements, and dispersion. The auth

  18. Recurrent Memory Array Structures

    OpenAIRE

    Rocki, Kamil

    2016-01-01

    The following report introduces ideas augmenting standard Long Short Term Memory (LSTM) architecture with multiple memory cells per hidden unit in order to improve its generalization capabilities. It considers both deterministic and stochastic variants of memory operation. It is shown that the nondeterministic Array-LSTM approach improves state-of-the-art performance on character level text prediction achieving 1.402 BPC on enwik8 dataset. Furthermore, this report estabilishes baseline neural...

  19. Solar collector array

    Science.gov (United States)

    Hall, John Champlin; Martins, Guy Lawrence

    2015-09-06

    A method and apparatus for efficient manufacture, assembly and production of solar energy. In one aspect, the apparatus may include a number of modular solar receiver assemblies that may be separately manufactured, assembled and individually inserted into a solar collector array housing shaped to receive a plurality of solar receivers. The housing may include optical elements for focusing light onto the individual receivers, and a circuit for electrically connecting the solar receivers.

  20. Spaceborne Processor Array

    Science.gov (United States)

    Chow, Edward T.; Schatzel, Donald V.; Whitaker, William D.; Sterling, Thomas

    2008-01-01

    A Spaceborne Processor Array in Multifunctional Structure (SPAMS) can lower the total mass of the electronic and structural overhead of spacecraft, resulting in reduced launch costs, while increasing the science return through dynamic onboard computing. SPAMS integrates the multifunctional structure (MFS) and the Gilgamesh Memory, Intelligence, and Network Device (MIND) multi-core in-memory computer architecture into a single-system super-architecture. This transforms every inch of a spacecraft into a sharable, interconnected, smart computing element to increase computing performance while simultaneously reducing mass. The MIND in-memory architecture provides a foundation for high-performance, low-power, and fault-tolerant computing. The MIND chip has an internal structure that includes memory, processing, and communication functionality. The Gilgamesh is a scalable system comprising multiple MIND chips interconnected to operate as a single, tightly coupled, parallel computer. The array of MIND components shares a global, virtual name space for program variables and tasks that are allocated at run time to the distributed physical memory and processing resources. Individual processor- memory nodes can be activated or powered down at run time to provide active power management and to configure around faults. A SPAMS system is comprised of a distributed Gilgamesh array built into MFS, interfaces into instrument and communication subsystems, a mass storage interface, and a radiation-hardened flight computer.

  1. Solar array construction

    Science.gov (United States)

    Crouthamel, Marvin S.; Coyle, Peter J.

    1982-01-01

    An interconnect tab on each cell of a first set of circular solar cells connects that cell in series with an adjacent cell in the set. This set of cells is arranged in alternate columns and rows of an array and a second set of similar cells is arranged in the remaining alternate columns and rows of the array. Three interconnect tabs on each solar cell of the said second set are employed to connect the cells of the second set to one another, in series and to connect the cells of the second set to those of the first set in parallel. Some tabs (making parallel connections) connect the same surface regions of adjacent cells to one another and others (making series connections) connect a surface region of one cell to the opposite surface region of an adjacent cell; however, the tabs are so positioned that the array may be easily assembled by depositing the cells in a certain sequence and in proper orientation.

  2. Array processor architecture

    Science.gov (United States)

    Barnes, George H. (Inventor); Lundstrom, Stephen F. (Inventor); Shafer, Philip E. (Inventor)

    1983-01-01

    A high speed parallel array data processing architecture fashioned under a computational envelope approach includes a data base memory for secondary storage of programs and data, and a plurality of memory modules interconnected to a plurality of processing modules by a connection network of the Omega gender. Programs and data are fed from the data base memory to the plurality of memory modules and from hence the programs are fed through the connection network to the array of processors (one copy of each program for each processor). Execution of the programs occur with the processors operating normally quite independently of each other in a multiprocessing fashion. For data dependent operations and other suitable operations, all processors are instructed to finish one given task or program branch before all are instructed to proceed in parallel processing fashion on the next instruction. Even when functioning in the parallel processing mode however, the processors are not locked-step but execute their own copy of the program individually unless or until another overall processor array synchronization instruction is issued.

  3. a 530-590 GHZ Schottky Heterodyne Receiver for High-Resolution Molecular Spectroscopy with Lille's Fast-Scan Fully Solid-State DDS Spectrometer

    Science.gov (United States)

    Pienkina, A.; Margulès, L.; Motiyenko, R. A.; Wiedner, Martina C.; Maestrini, Alain; Defrance, Fabien

    2017-06-01

    Laboratory spectroscopy, especially at THz and mm-wave ranges require the advances in instrumentation techniques to provide high resolution of the recorded spectra with precise frequency measurement that facilitates the mathematical treatment. We report the first implementation of a Schottky heterodyne receiver, operating at room temperature and covering the range between 530 and 590 GHz, for molecular laboratory spectroscopy. A 530-590 GHz non-cryogenic Schottky solid-state receiver was designed at LERMA, Observatoire de Paris and fabricated in partnership with LPN- CNRS (Laboratoire de Photonique et de Nanostructures), and was initially developed for ESA Jupiter Icy Moons Explorer (JUICE), intended to observe Jupiter and its icy moon atmospheres. It is based on a sub-harmonic Schottky diode mixer, designed and fabricated at LERMA-LPN, pumped by a Local Oscillator (LO), consisting of a frequency Amplifier/Multiplier chains (AMCs) from RPG (Radiometer Physics GmBh). The performance of the receiver was demonstrated by absorption spectroscopy of CH_3CH_2CN with Lille's fast-scan DDS spectrometer. A series of test measurements showed the receiver's good sensitivity, stability and frequency accuracy comparable to those of 4K QMC bolometers, thus making room-temperature Schottky receiver a competitive alternative to 4K QMC bolometers to laboratory spectroscopy applications. We will present the first results with such a combination of a compact room temperature Schottky heterodyne receiver and a fast-scan DDS spectrometer. J. Treuttel, L. Gatilova, A. Maestrini et al., 2016, IEEE Trans. Terahertz Science and Tech., 6, 148-155. This work was funded by the French ANR under the Contract No. ANR-13-BS05-0008-02 IMOLABS.

  4. UAVSAR Phased Array Aperture

    Science.gov (United States)

    Chamberlain, Neil; Zawadzki, Mark; Sadowy, Greg; Oakes, Eric; Brown, Kyle; Hodges, Richard

    2009-01-01

    This paper describes the development of a patch antenna array for an L-band repeat-pass interferometric synthetic aperture radar (InSAR) instrument that is to be flown on an unmanned aerial vehicle (UAV). The antenna operates at a center frequency of 1.2575 GHz and with a bandwidth of 80 MHz, consistent with a number of radar instruments that JPL has previously flown. The antenna is designed to radiate orthogonal linear polarizations in order to facilitate fully-polarimetric measurements. Beam-pointing requirements for repeat-pass SAR interferometry necessitate electronic scanning in azimuth over a range of -20degrees in order to compensate for aircraft yaw. Beam-steering is accomplished by transmit/receive (T/R) modules and a beamforming network implemented in a stripline circuit board. This paper, while providing an overview of phased array architecture, focuses on the electromagnetic design of the antenna tiles and associated interconnects. An important aspect of the design of this antenna is that it has an amplitude taper of 10dB in the elevation direction. This is to reduce multipath reflections from the wing that would otherwise be detrimental to interferometric radar measurements. This taper is provided by coupling networks in the interconnect circuits as opposed to attenuating the output of the T/R modules. Details are given of material choices and fabrication techniques that meet the demanding environmental conditions that the antenna must operate in. Predicted array performance is reported in terms of co-polarized and crosspolarized far-field antenna patterns, and also in terms of active reflection coefficient.

  5. MEASUREMENTS OF CO REDSHIFTS WITH Z-SPEC FOR LENSED SUBMILLIMETER GALAXIES DISCOVERED IN THE H-ATLAS SURVEY

    Energy Technology Data Exchange (ETDEWEB)

    Lupu, R. E.; Scott, K. S.; Aguirre, J. E. [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104 (United States); Aretxaga, I. [Instituto Nacional de Astrofisica, Optica y Electronica, Aptdo. Postal 51 y 216, 72000 Puebla (Mexico); Auld, R.; Dariush, A. [School of Physics and Astronomy, Cardiff University, The Parade, Cardiff CF24 3AA (United Kingdom); Barton, E.; Cooke, J.; Cooray, A. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Beelen, A. [Institut d' Astrophysique spatiale bat 121-Universite Paris-Sud, F-91405 Orsay Cedex (France); Bertoldi, F. [Argelander Institute for Astronomy, Bonn University, Auf dem Huegel 71, D-53121 Bonn (Germany); Bock, J. J.; Bradford, C. M. [Jet Propulsion Laboratory, Pasadena, CA 91109 (United States); Bonfield, D. [Centre for Astrophysics Research, Science and Technology Research Centre, University of Hertfordshire, Herts AL10 9AB (United Kingdom); Buttiglione, S.; De Zotti, G. [INAF, Osservatorio Astronomico di Padova, Vicolo Osservatorio 5, I-35122 Padova (Italy); Cava, A. [Instituto de Astrofisica de Canarias, C/Via Lactea s/n, E-38200 La Laguna (Spain); Clements, D. L. [Astrophysics Group, Physics Department, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ (United Kingdom); Dannerbauer, H. [Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot, DAPNIA/Service d' Astrophysique, CEA Saclay, Orme des Merisiers, F-91191 Gif-sur-Yvette Cedex (France); Dunne, L., E-mail: Roxana.E.Lupu@nasa.gov [School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom); and others

    2012-10-01

    We present new observations from Z-Spec, a broadband 185-305 GHz spectrometer, of five submillimeter bright lensed sources selected from the Herschel-Astrophysical Terahertz Large Area Survey science demonstration phase catalog. We construct a redshift-finding algorithm using combinations of the signal to noise of all the lines falling in the Z-Spec bandpass to determine redshifts with high confidence, even in cases where the signal to noise in individual lines is low. We measure the dust continuum in all sources and secure CO redshifts for four out of five (z {approx} 1.5-3). In one source, SDP.17, we tentatively identify two independent redshifts and a water line, confirmed at z = 2.308. Our sources have properties characteristic of dusty starburst galaxies, with magnification-corrected star formation rates of 10{sup 2-3} M{sub Sun} yr{sup -1}. Lower limits for the dust masses ({approx} a few 10{sup 8} M{sub Sun }) and spatial extents ({approx}1 kpc equivalent radius) are derived from the continuum spectral energy distributions, corresponding to dust temperatures between 54 and 69 K. In the local thermodynamic equilibrium (LTE) approximation, we derive relatively low CO excitation temperatures ({approx}< 100 K) and optical depths ({tau} {approx}< 1). Performing a non-LTE excitation analysis using RADEX, we find that the CO lines measured by Z-Spec (from J = 4 {yields} 3 to 10 {yields} 9, depending on the galaxy) localize the best solutions to either a high-temperature/low-density region or a low/temperature/high-density region near the LTE solution, with the optical depth varying accordingly. Observations of additional CO lines, CO(1-0) in particular, are needed to constrain the non-LTE models.

  6. Active bacteriophage biocontrol and therapy on sub-millimeter scales towards removal of unwanted bacteria from foods and microbiomes

    Directory of Open Access Journals (Sweden)

    Stephen T. Abedon

    2017-08-01

    Full Text Available Bacteriophages can be used as antibacterial agents as a form of biological control, e.g., such as phage therapy. With active treatment, phages must “actively” produce new virions, in situ, to attain “inundative” densities, i.e., sufficient titers to eradicate bacteria over reasonable timeframes. Passive treatment, by contrast, can be accomplished using phages that are bactericidal but incapable of generating new phage virions in situ during their interaction with target bacteria. These ideas of active versus passive treatment come from theoretical considerations of phage therapy pharmacology, particularly as developed in terms of phage application to well-mixed cultures consisting of physically unassociated bacteria. Here I extend these concepts to bacteria which instead are physically associated. These are bacteria as found making up cellular arrangements or bacterial microcolonies—collectively, clonal bacterial “clumps”. I consider circumstances where active phage replication would be required to effect desired levels of bacterial clearance, but populations of bacteria nevertheless are insufficiently prevalent to support phage replication to bacteria-inundative densities across environments. Clumped bacteria, however, may still support active treatment at more local, i.e., sub-millimeter, within-clump spatial scales, and potential consequences of this are explored mathematically. Application is to the post-harvest biocontrol of foodborne pathogens, and potentially also to precise microbiome editing. Adequate infection performance by phages in terms of timely burst sizes, that is, other than just adsorption rates and bactericidal activity, thus could be important for treatment effectiveness even if bacterial densities overall are insufficient to support active treatment across environments. Poor phage replication during treatment of even low bacterial numbers, such as given food refrigeration during treatment, consequently could

  7. Comparing submillimeter polarized emission with near-infrared polarization of background stars for the Vela C molecular cloud

    Science.gov (United States)

    Santos, Fabio P.; Ade, Peter; Angilè, Francesco E.; Ashton, Peter; Benton, Steven J.; Devlin, Mark J.; Dober, Bradley; Fissel, Laura M.; Fukui, Yasuo; Galitzki, Nicholas; Gandilo, Natalie; Klein, Jeffrey; Li, Zhi-Yun; Korotkov, Andrei; Martin, Peter G.; Matthews, Tristan; Moncelsi, Lorenzo; nakamura, fumitaka; Barth Netterfield, Calvin; Novak, Giles; Pascale, Enzo; Poidevin, Frédérick; Savini, Giorgio; Scott, Douglas; Shariff, Jamil; Soler, Juan D.; Thomas, Nicholas; tucker, carole; Tucker, Gregory S.; Ward-Thompson, Derek; BLASTPOL

    2016-06-01

    We present a large-scale combination of near-infrared (near-IR) interstellar polarization data from background starlight, with polarized emission data at sub-millimetric (sub-mm) bands for the Vela C molecular cloud. The sub-mm data were obtained by the Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry (BLASTPol) during the 2012 flight in Antartica. The near-IR data consist of more than 6700 detections in the I-band, covering a wide area around the cloud, mostly in the range of visual extinctions between 2 and 16 mag. The main goal was to determine the polarization efficiency ratio Reff , defined as p500/(pI/τV), where p500 is the polarization fraction at 500 μm and optical depths τV are estimated from cataloged near-IR photometry. To ensure that the same column density of material is producing both polarization from emission and extinction, we introduce a new method to select stars that are located in the near-background, the Gaussian-logistic (GL) technique. The polarization efficiency ratio is critically affected by stellar objects with background contamination from the diffuse Galactic material, emphasizing the need for a careful selection. Accounting for the statistical and systematic uncertainties from the GL method, we estimate an average Reff value of 2.4 ± 0.8, which can be used to test dust grain models designed specifically for molecular clouds. Reff appears to be relatively flat as a function of the cloud depth, suggesting that significant grain modification might occur only at higher densities.

  8. The Level 2 research product algorithms for the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES

    Directory of Open Access Journals (Sweden)

    P. Baron

    2011-10-01

    Full Text Available This paper describes the algorithms of the level-2 research (L2r processing chain developed for the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES. The chain has been developed in parallel to the operational chain for conducting researches on calibration and retrieval algorithms. L2r chain products are available to the scientific community. The objective of version 2 is the retrieval of the vertical distribution of trace gases in the altitude range of 18–90 km. A theoretical error analysis is conducted to estimate the retrieval feasibility of key parameters of the processing: line-of-sight elevation tangent altitudes (or angles, temperature and ozone profiles. While pointing information is often retrieved from molecular oxygen lines, there is no oxygen line in the SMILES spectra, so the strong ozone line at 625.371 GHz has been chosen. The pointing parameters and the ozone profiles are retrieved from the line wings which are measured with high signal to noise ratio, whereas the temperature profile is retrieved from the optically thick line center. The main systematic component of the retrieval error was found to be the neglect of the non-linearity of the radiometric gain in the calibration procedure. This causes a temperature retrieval error of 5–10 K. Because of these large temperature errors, it is not possible to construct a reliable hydrostatic pressure profile. However, as a consequence of the retrieval of pointing parameters, pressure induced errors are significantly reduced if the retrieved trace gas profiles are represented on pressure levels instead of geometric altitude levels. Further, various setups of trace gas retrievals have been tested. The error analysis for the retrieved HOCl profile demonstrates that best results for inverting weak lines can be obtained by using narrow spectral windows.

  9. Millimeter/Submillimeter Spectroscopy of TiO (X3Δr): The Rare Titanium Isotopologues

    Science.gov (United States)

    Lincowski, A. P.; Halfen, D. T.; Ziurys, L. M.

    2016-12-01

    Pure rotational spectra of the rare isotopologues of titanium oxide, 46TiO, 47TiO, 49TiO, and 50TiO, have been recorded using a combination of Fourier transform millimeter-wave (FTmmW) and millimeter/submillimeter direct absorption techniques in the frequency range 62-538 GHz. This study is the first complete spectroscopic characterization of these species in their X 3Δ r ground electronic states. The isotopologues were created by the reaction of N2O or O2 and titanium vapor, produced either by laser ablation or in a Broida-type oven, and observed in the natural Ti isotopic abundances. Between 10 and 11 rotational transitions J + 1 ≤ftrightarrow J were measured for each species, typically in all 3 spin-orbit ladders Ω = 1, 2, and 3. For 47TiO and 49TiO, hyperfine structure was resolved, originating from the titanium-47 and titanium-49 nuclear spins of I = 5/2 and 7/2, respectively. For the Ω = 1 and 3 components, the hyperfine structure was found to follow a classic Landé pattern, while that for Ω = 2 appeared to be perturbed, likely a result of mixing with the nearby isoconfigurational a 1Δ state. The spectra were analyzed with a case (a) Hamiltonian, and rotational, spin-orbit, and spin-spin parameters were determined for each species, as well as magnetic hyperfine and electric quadrupole constants for the two molecules with nuclear spins. The most abundant species, 48TiO, has been detected in circumstellar envelopes. These measurements will enable other titanium isotopologues to be studied at millimeter wavelengths, providing Ti isotope ratios that can test models of nucleosynthesis.

  10. A Lambda Calculus for Transfinite Arrays: Unifying Arrays and Streams

    OpenAIRE

    Sinkarovs, Artjoms; Scholz, Sven-Bodo

    2017-01-01

    Array programming languages allow for concise and generic formulations of numerical algorithms, thereby providing a huge potential for program optimisation such as fusion, parallelisation, etc. One of the restrictions that these languages typically have is that the number of elements in every array has to be finite. This means that implementing streaming algorithms in such languages requires new types of data structures, with operations that are not immediately compatible with existing array ...

  11. Selecting Sums in Arrays

    DEFF Research Database (Denmark)

    Brodal, Gerth Stølting; Jørgensen, Allan Grønlund

    2008-01-01

    In an array of n numbers each of the \\binomn2+nUnknown control sequence '\\binom' contiguous subarrays define a sum. In this paper we focus on algorithms for selecting and reporting maximal sums from an array of numbers. First, we consider the problem of reporting k subarrays inducing the k largest...... sums among all subarrays of length at least l and at most u. For this problem we design an optimal O(n + k) time algorithm. Secondly, we consider the problem of selecting a subarray storing the k’th largest sum. For this problem we prove a time bound of Θ(n · max {1,log(k/n)}) by describing...... an algorithm with this running time and by proving a matching lower bound. Finally, we combine the ideas and obtain an O(n· max {1,log(k/n)}) time algorithm that selects a subarray storing the k’th largest sum among all subarrays of length at least l and at most u....

  12. Electromagnetically Clean Solar Arrays

    Science.gov (United States)

    Stem, Theodore G.; Kenniston, Anthony E.

    2008-01-01

    The term 'electromagnetically clean solar array' ('EMCSA') refers to a panel that contains a planar array of solar photovoltaic cells and that, in comparison with a functionally equivalent solar-array panel of a type heretofore used on spacecraft, (1) exhibits less electromagnetic interferences to and from other nearby electrical and electronic equipment and (2) can be manufactured at lower cost. The reduction of electromagnetic interferences is effected through a combination of (1) electrically conductive, electrically grounded shielding and (2) reduction of areas of current loops (in order to reduce magnetic moments). The reduction of cost is effected by designing the array to be fabricated as a more nearly unitary structure, using fewer components and fewer process steps. Although EMCSAs were conceived primarily for use on spacecraft they are also potentially advantageous for terrestrial applications in which there are requirements to limit electromagnetic interference. In a conventional solar panel of the type meant to be supplanted by an EMCSA panel, the wiring is normally located on the back side, separated from the cells, thereby giving rise to current loops having significant areas and, consequently, significant magnetic moments. Current-loop geometries are chosen in an effort to balance opposing magnetic moments to limit far-0field magnetic interactions, but the relatively large distances separating current loops makes full cancellation of magnetic fields problematic. The panel is assembled from bare photovoltaic cells by means of multiple sensitive process steps that contribute significantly to cost, especially if electomagnetic cleanliness is desired. The steps include applying a cover glass and electrical-interconnect-cell (CIC) sub-assemble, connecting the CIC subassemblies into strings of series-connected cells, laying down and adhesively bonding the strings onto a panel structure that has been made in a separate multi-step process, and mounting the

  13. Electrodynamic Arrays Having Nanomaterial Electrodes

    Science.gov (United States)

    Trigwell, Steven (Inventor); Biris, Alexandru S. (Inventor); Calle, Carlos I. (Inventor)

    2013-01-01

    An electrodynamic array of conductive nanomaterial electrodes and a method of making such an electrodynamic array. In one embodiment, a liquid solution containing nanomaterials is deposited as an array of conductive electrodes on a substrate, including rigid or flexible substrates such as fabrics, and opaque or transparent substrates. The nanomaterial electrodes may also be grown in situ. The nanomaterials may include carbon nanomaterials, other organic or inorganic nanomaterials or mixtures.

  14. Combinatorial aspects of covering arrays

    Directory of Open Access Journals (Sweden)

    Charles J. Colbourn

    2004-11-01

    Full Text Available Covering arrays generalize orthogonal arrays by requiring that t -tuples be covered, but not requiring that the appearance of t -tuples be balanced.Their uses in screening experiments has found application in software testing, hardware testing, and a variety of fields in which interactions among factors are to be identified. Here a combinatorial view of covering arrays is adopted, encompassing basic bounds, direct constructions, recursive constructions, algorithmic methods, and applications.

  15. Rapid Sintering of Silica Xerogel Ceramic Derived from Sago Waste Ash Using Sub-millimeter Wave Heating with a 300 GHz CW Gyrotron

    Science.gov (United States)

    Aripin, Haji; Mitsudo, Seitaro; Sudiana, I. Nyoman; Tani, Shinji; Sako, Katsuhide; Fujii, Yutaka; Saito, Teruo; Idehara, Toshitaka; Sabchevski, Sliven

    2011-06-01

    In this paper, we present and discuss experimental results from a microwave sintering of a silica-glass ceramic, produced from a silica xerogel extracted from a sago waste ash. As a radiation source for the microwave heating a sub-millimeter wave gyrotron (Gyrotron FU CW I) with an output frequency of 300 GHz has been used. The powders of silica xerogel have been dry pressed and then sintered at temperatures ranging from 300°C to 1500°C. The influence of the sintering temperature on the technological properties such as porosity and bulk density was studied in detail. Furthermore, X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR) spectroscopy have been used in order to study the structure of the produced silica glass-ceramics. It has been found that the silica xerogel crystallizes at a temperature of 800°C, which is about 200°C lower than the one observed in the conventional process. The silica xerogel samples sintered by their irradiation with a sub-millimeter wave at 900°C for 18 minutes are fully crystallized into a silica glass-ceramic with a density of about 2.2 g/cm3 and cristobalite as a major crystalline phase. The results obtained in this study allow one to conclude that the microwave sintering with sub-millimeter waves is an appropriate technological process for production of silica glass-ceramics from a silica xerogel and is characterized with such advantages as shorter times of the thermal cycle, lower sintering temperatures and higher quality of the final product.

  16. Compact dynamic microfluidic iris array

    Science.gov (United States)

    Kimmle, Christina; Doering, Christoph; Steuer, Anna; Fouckhardt, Henning

    2011-09-01

    A dynamic microfluidic iris is realized. Light attenuation is achieved by absorption of an opaque liquid (e.g. black ink). The adjustment of the iris diameter is achieved by fluid displacement via a transparent elastomer (silicone) half-sphere. This silicone calotte is hydraulically pressed against a polymethylmethacrylate (PMMA) substrate as the bottom window, such that the opaque liquid is squeezed away, this way opening the iris. With this approach a dynamic range of more than 60 dB can be achieved with response times in the ms to s regime. The design allows the realization of a single iris as well as an iris array. So far the master for the molded silicone structure was fabricated by precision mechanics. The aperture diameter was changed continuously from 0 to 8 mm for a single iris and 0 to 4 mm in case of a 3 x 3 iris array. Moreover, an iris array was combined with a PMMA lens array into a compact module, the distance of both arrays equaling the focal length of the lenses. This way e.g. spatial frequency filter arrays can be realized. The possibility to extend the iris array concept to an array with many elements is demonstrated. Such arrays could be applied e.g. in light-field cameras.

  17. The Sensitivity of the Next Generation Very Large Array (ngVLA)

    Science.gov (United States)

    Butler, Bryan; Grammer, Wes; Selina, Rob; Murphy, Eric Joseph; Carilli, Chris

    2018-01-01

    The design for the Next Generation Very Large Array (ngVLA) is now mature enough to make a much more detailed calculation of sensitivity than has been possible before. Previous estimates have suffered from uncertainties in design specifics, many of which have been reduced through further development. We use a more detailed model of antenna and feed design to estimate the aperture efficiency, and receiver designs that in some cases have been prototyped to estimate the receiver temperature. The atmospheric contribution to the system temperature is calculated using the most current measurements of atmospheric conditions at the Karl G. Jansky Very Large Array (VLA) site and in the surrounding region. Given this information an estimate of the point source sensitivity is calculated with much more confidence than previously. We compare these ngVLA sensitivity numbers directly with existing and near-future instruments in the frequency range of ngVLA (1.2 to 116 GHz), namely the current VLA, the Atacama Large Millimeter/submillimeter Array (ALMA) and the Square Kilometer Array phase 1 for Mid frequencies (SKA1-Mid). We find that the ngVLA, with its current design, is roughly a factor of 10 more sensitive than VLA and ALMA, and factor of 6-7 more sensitive than SKA1-Mid (current deployment baseline) for spectral line observations, and almost a factor of 20 more sensitive than all three for continuum observations due to increased collecting area and bandwidth above 20 GHz (should SKA1-Mid eventually include receivers above the 14 GHz max frequency in the current deployment baseline design). These calculations will remain under investigation as the project matures. The values presented herein represent the state of the project as it stands today, and can be used to inform studies of the scientific potential of the ngVLA.

  18. Cascading Constrained 2-D Arrays using Periodic Merging Arrays

    DEFF Research Database (Denmark)

    Forchhammer, Søren; Laursen, Torben Vaarby

    2003-01-01

    We consider a method for designing 2-D constrained codes by cascading finite width arrays using predefined finite width periodic merging arrays. This provides a constructive lower bound on the capacity of the 2-D constrained code. Examples include symmetric RLL and density constrained codes...

  19. THE STAR FORMATION HISTORIES OF z {approx} 2 DUST-OBSCURED GALAXIES AND SUBMILLIMETER-SELECTED GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Bussmann, R. S. [Harvard-Smithsonian Center for Astrophysics, 160 Concord Avenue, Cambridge, MA 02138 (United States); Dey, Arjun; Jannuzi, B. T. [National Optical Astronomy Observatory, 950 N. Cherry Avenue, Tucson, AZ 85719 (United States); Armus, L.; Desai, V.; Soifer, B. T. [Spitzer Science Center, California Institute of Technology, MS 220-6, Pasadena, CA 91125 (United States); Brown, M. J. I. [School of Physics, Monash University, Clayton, Victoria 3800 (Australia); Gonzalez, A. H. [Department of Astronomy, University of Florida, Gainesville, FL 32611 (United States); Melbourne, J., E-mail: rbussmann@cfa.harvard.edu [Division of Physics, Math and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States)

    2012-01-10

    The Spitzer Space Telescope has identified a population of ultraluminous infrared galaxies (ULIRGs) at z {approx} 2 that may play an important role in the evolution of massive galaxies. We measure the stellar masses (M{sub *}) of two populations of Spitzer-selected ULIRGs that have extremely red R - [24] colors (dust-obscured galaxies, or DOGs) and compare our results with submillimeter-selected galaxies (SMGs). One set of 39 DOGs has a local maximum in their mid-infrared (mid-IR) spectral energy distribution (SED) at rest frame 1.6 {mu}m associated with stellar emission ({sup b}ump DOGs{sup )}, while the other set of 51 DOGs have power-law mid-IR SEDs that are typical of obscured active galactic nuclei ({sup p}ower-law DOGs{sup )}. We measure M{sub *} by applying Charlot and Bruzual stellar population synthesis models to broadband photometry in the rest-frame ultraviolet, optical, and near-infrared of each of these populations. Assuming a simple stellar population and a Chabrier initial mass function, we find that power-law DOGs and bump DOGs are on average a factor of 2 and 1.5 more massive than SMGs, respectively (median and inter-quartile M{sub *} values for SMGs, bump DOGs, and power-law DOGs are log(M{sub *}/M{sub Sun }) = 10.42{sup +0.42}{sub -0.36}, 10.62{sup +0.36}{sub -0.32}, and 10.71{sup +0.40}{sub -0.34}, respectively). More realistic star formation histories drawn from two competing theories for the nature of ULIRGs at z {approx} 2 (major merger versus smooth accretion) can increase these mass estimates by up to 0.5 dex. A comparison of our stellar masses with the instantaneous star formation rate (SFR) in these z {approx} 2 ULIRGs provides a preliminary indication supporting high SFRs for a given M{sub *}, a situation that arises more naturally in major mergers than in smooth accretion-powered systems.

  20. Frequency Diverse Array Receiver Architectures

    Science.gov (United States)

    2015-06-29

    2009. DSP /SPE 2009. IEEE 13th, pp. 446 –450, Jan. 2009. 60 [19] Fuhrmann, D.R. and Browning, J.P. and Rangaswamy, M., “Adapting a MIMO/phased-array...Diverse Array Radar,” Master’s thesis, Naval Postgraduate School, September 2010. [25] D. Glass, “ Matlab 4-d visualization technique.” Personal

  1. The NOAA TOGA antenna array

    Science.gov (United States)

    Ecklund, W. L.; Carter, D. A.; Balsley, B. B.

    1986-01-01

    The Aeronomy Laboratory recently installed a 100 x 100 meter array antenna with limited beam steering on Christmas Island as a part of the TOGA (Tropical Ocean and Global Atmosphere) program. The array and the associated beam steering and indicating hardware are described.

  2. The OncoArray Consortium

    DEFF Research Database (Denmark)

    Amos, Christopher I; Dennis, Joe; Wang, Zhaoming

    2017-01-01

    BACKGROUND: Common cancers develop through a multistep process often including inherited susceptibility. Collaboration among multiple institutions, and funding from multiple sources, has allowed the development of an inexpensive genotyping microarray, the OncoArray. The array includes a genome-wi...

  3. Chunking of Large Multidimensional Arrays

    Energy Technology Data Exchange (ETDEWEB)

    Rotem, Doron; Otoo, Ekow J.; Seshadri, Sridhar

    2007-02-28

    Data intensive scientific computations as well on-lineanalytical processing applications as are done on very large datasetsthat are modeled as k-dimensional arrays. The storage organization ofsuch arrays on disks is done by partitioning the large global array intofixed size hyper-rectangular sub-arrays called chunks or tiles that formthe units of data transfer between disk and memory. Typical queriesinvolve the retrieval of sub-arrays in a manner that accesses all chunksthat overlap the query results. An important metric of the storageefficiency is the expected number of chunks retrieved over all suchqueries. The question that immediately arises is "what shapes of arraychunks give the minimum expected number of chunks over a query workload?"In this paper we develop two probabilistic mathematical models of theproblem and provide exact solutions using steepest descent and geometricprogramming methods. Experimental results, using synthetic workloads onreal life data sets, show that our chunking is much more efficient thanthe existing approximate solutions.

  4. Digital electrostatic acoustic transducer array

    KAUST Repository

    Carreno, Armando Arpys Arevalo

    2016-12-19

    In this paper we present the fabrication and characterization of an array of electrostatic acoustic transducers. The array is micromachined on a silicon wafer using standard micro-machining techniques. Each array contains 2n electrostatic transducer membranes, where “n” is the bit number. Every element of the array has a hexagonal membrane shape structure, which is separated from the substrate by 3µm air gap. The membrane is made out 5µm thick polyimide layer that has a bottom gold electrode on the substrate and a gold top electrode on top of the membrane (250nm). The wafer layout design was diced in nine chips with different array configurations, with variation of the membrane dimensions. The device was tested with 90 V giving and sound output level as high as 35dB, while actuating all the elements at the same time.

  5. SAQC: SNP Array Quality Control

    Directory of Open Access Journals (Sweden)

    Li Ling-Hui

    2011-04-01

    Full Text Available Abstract Background Genome-wide single-nucleotide polymorphism (SNP arrays containing hundreds of thousands of SNPs from the human genome have proven useful for studying important human genome questions. Data quality of SNP arrays plays a key role in the accuracy and precision of downstream data analyses. However, good indices for assessing data quality of SNP arrays have not yet been developed. Results We developed new quality indices to measure the quality of SNP arrays and/or DNA samples and investigated their statistical properties. The indices quantify a departure of estimated individual-level allele frequencies (AFs from expected frequencies via standardized distances. The proposed quality indices followed lognormal distributions in several large genomic studies that we empirically evaluated. AF reference data and quality index reference data for different SNP array platforms were established based on samples from various reference populations. Furthermore, a confidence interval method based on the underlying empirical distributions of quality indices was developed to identify poor-quality SNP arrays and/or DNA samples. Analyses of authentic biological data and simulated data show that this new method is sensitive and specific for the detection of poor-quality SNP arrays and/or DNA samples. Conclusions This study introduces new quality indices, establishes references for AFs and quality indices, and develops a detection method for poor-quality SNP arrays and/or DNA samples. We have developed a new computer program that utilizes these methods called SNP Array Quality Control (SAQC. SAQC software is written in R and R-GUI and was developed as a user-friendly tool for the visualization and evaluation of data quality of genome-wide SNP arrays. The program is available online (http://www.stat.sinica.edu.tw/hsinchou/genetics/quality/SAQC.htm.

  6. Experimental investigation with respect to the performance of deep submillimeter-scaled textured tools in dry turning titanium alloy Ti-6Al-4V

    Science.gov (United States)

    Li, Ning; Chen, Yongjie; Kong, Dongdong; Tan, Shenglin

    2017-05-01

    Titanium alloy Ti-6Al-4V falls under the category of the most difficult to machine materials due to its inherent high strength maintained at elevated temperature and low thermal conductivity. Based on size effect, the poor machinability may be improved by surface texturing on the tools. Thus, the effect of deep submillimeter-scaled textures on the cutting performance in Ti-6Al-4V turning was investigated. To this end, three kinds of surface textures with different sizes were fabricated using femtosecond laser on rake faces of the uncoated cemented carbide (WC/Co) inserts. Then, dry cutting experiments were conducted with these textured inserts and conventional inserts under the condition of cutting speed Vc = 50m/min, depth of cut ap = 2 mm, and feed rate f = 0.3 mm/rev. The cutting performance is evaluated in terms of cutting forces, coefficient of friction at the tool-chip interface. Results obtained in this work show the feasibility of fabricating deep submillimeter-scaled textures on tool rake face to improve the machinability of Ti-6Al-4V. The parallel type of textured tool P01 demonstrates the best performance in both reducing cutting force and improving the friction properties on the rake face. This result can be explained by the reduced tool-chip contact area and the ploughing effect.

  7. Planning a Global Array of Broadband Seismic Arrays

    Science.gov (United States)

    Koper, Keith D.; Ammon, Charles J.

    2013-08-01

    A diverse group of more than 70 seismologists met for 2 days in Raleigh, N.C., to report on recent innovations in seismic array methods and to discuss the future of seismic arrays in global seismology. The workshop was sponsored by the Incorporated Research Institutions for Seismology (IRIS), with U.S. National Science Foundation funding. Participants included representatives of existing array research groups in Australia, Canada, Germany, Japan, Norway, and the United States, with individuals from academia, government, and industry. The workshop was organized by the authors of this meeting report, Pablo Ampeuro (California Institute of Technology), and Colleen Dalton (Boston University), along with IRIS staff support.

  8. Column measurements and vertical profiling of CO2 and CH4 based on high resolution ground-based NIR heterodyne spetro-radiometry

    Science.gov (United States)

    Klimchuk, Artem; Semenov, Vladimir; Churbanov, Dmitry; Zenevich, Sergey; Rodin, Alexander

    2017-04-01

    A compact, lightweight heterodyne NIR spectro-radiometer suitable for ground-based atmospheric sounding by direct spectro-radimetry of Sun spectrum with spectral resolution ˜0.0006 cm-1 has been used for column measurements and vertical profiling of methane and carbon dioxide. Highly stabilized DFB laser was used as local oscillator. Radiation mixed in the single mode fiber was detected by InGaAs photodiode within the bandpass of ˜20 MHz. Wavelength coverage of spectral measurement was provided by sweeping local oscillator frequency in the range 1-1.5 cm-1. With the exposure time of 3 minutes, the absorption spectrum of the atmosphere over Moscow has been recorded with S/N ˜300. The retrieved methane profile demonstrates higher abundances in the lower scale height compared to the assumed model profile, well expected in the megalopolis center. The retrievals sensitivity is limited by 10 ppb, with the exception of the lower part of the profile where the tendency to lower values is revealed. Thus the methane abundance variations may be evaluated with relative accuracy better than 1%, which fits the requirements of greenhouse gas monitoring. The CO2 column measurements was provided an accuracy 0.4%

  9. Cryogenic testing and multi-chip module design of a 31.3-45GHz MHEMT MMIC-based heterodyne receiver for radio astronomy

    Science.gov (United States)

    Hwang, Yuh-Jing; Chiong, Chau-Ching; Chang, Su-Wei; Wei, Tashun; Wong, Wei-Ting; Lin, Yo-Shen; Chen, Ming-Tang; Wang, Huei; Chang, Hong-Yeh

    2008-07-01

    A prototype Q-band millimeter-wave heterodyne receiver based on monolithic microwave integrated circuit (MMIC) chips is designed and tested. The MMIC chips, including two three-stage 31.3-45GHz low-noise amplifier (LNA), a diode balanced mixer and a 4-12GHz IF amplifier, are fabricated by a 0.15-um Gallium-Arsenide (GaAs) metamorphic high-electron mobility transistor (MHEMT) foundry service. The MMIC chips are measured by probe in the gain stage. The three-stage 31.3-45GHz LNA MMIC exhibits 31-35dB gain and 2.8-3.5dB noise figure under room temperature environment. The balanced diode mixer with 31.3-45.0GHz RF frequency range and 27.3-33GHz LO frequency range shows 10-13dB conversion loss under 10-dBm LO pumping over 4-12GHz IF frequency range. The LO power of the mixer is provided by a phase-locked GaAs hetero-junction bipolar transistor (HBT) MMIC voltage-controlled oscillator cascaded by a buffer amplifier. The packaged modules of the individual MHEMT MMIC receiver components are designed for testing under 15-20K cryogenic operating temperature to ensure the low-noise performance. A compact multi-chip receiver module design concept will be presented.

  10. Low-Cost Miniaturized Laser Heterodyne Radiometer for Highly Sensitive Detection of CO2 and CH4 in the Atmospheric Column

    Science.gov (United States)

    Wilson, Emily L.; McLinden, Matthew L.; Miller, J. Houston

    2011-01-01

    We present a new passive ground-network instrument capable of measuring carbon dioxide (CO2) at 1.57 microns and methane (CH4) at 1.62 microns -- key for validation of OCO-2, ASCENDS, OCO-3, and GOSAT. Designed to piggy-back on an AERONET sun tracker (AERONET is a global network of more than 450 aerosol sensing instruments), this instrument could be rapidly deployed into the established AERONET network of ground sensors. Because aerosols induce a radiative effect that influences terrestrial carbon exchange, this simultaneous measure of aerosols and carbon cycle gases offers a uniquely comprehensive approach. This instrument is a variation of a laser heterodyne radiometer (LHR) that leverages recent advances in telecommunications lasers to miniaturize the instrument (the current version fits in a carry-on suitcase). In this technique, sunlight that has undergone absorption by the trace gas is mixed with laser light at a frequency matched to a trace gas absorption feature in the infrared (IR). Mixing results in a beat signal in the RF (radio frequency) region that can be related to the atmospheric concentration. By dividing this RF signal into a filter bank, concentrations at different altitudes can be resolved. For a one second integration, we estimate column sensitivities of 0.1 ppmv for CO2, and <1 ppbv for CH4.

  11. Water Orientation at Ceramide/Water Interfaces Studied by Heterodyne-Detected Vibrational Sum Frequency Generation Spectroscopy and Molecular Dynamics Simulation

    KAUST Repository

    Adhikari, Aniruddha

    2016-10-10

    Lipid/water interaction is essential for many biological processes. The water structure at the nonionic lipid interface remains little known, and there is no scope of a priori prediction of water orientation at nonionic interfaces, either. Here, we report our study combining advanced nonlinear spectroscopy and molecular dynamics simulation on the water orientation at the ceramide/water interface. We measured χ spectrum in the OH stretch region of ceramide/isotopically diluted water interface using heterodyne-detected vibrational sum-frequency generation spectroscopy and found that the interfacial water prefers an overall hydrogen-up orientation. Molecular dynamics simulation indicates that this preferred hydrogen-up orientation of water is determined by a delicate balance between hydrogen-up and hydrogen-down orientation induced by lipid-water and intralipid hydrogen bonds. This mechanism also suggests that water orientation at neutral lipid interfaces depends highly on the chemical structure of the lipid headgroup, in contrast to the charged lipid interfaces where the net water orientation is determined solely by the charge of the lipid headgroup.

  12. Inter-comparison of 2 microm Heterodyne Differential Absorption Lidar, Laser Diode Spectrometer, LICOR NDIR analyzer and flasks measurements of near-ground atmospheric CO2 mixing ratio.

    Science.gov (United States)

    Gibert, Fabien; Joly, Lilian; Xuéref-Rémy, Irène; Schmidt, Martina; Royer, Adrien; Flamant, Pierre H; Ramonet, Michel; Parvitte, Bertrand; Durry, Georges; Zéninari, Virginie

    2009-01-01

    Remote sensing and in situ instruments are presented and compared in the same location for accurate CO(2) mixing ratio measurements in the atmosphere: (1) a 2.064 microm Heterodyne DIfferential Absorption Lidar (HDIAL), (2) a field deployable infrared Laser Diode Spectrometer (LDS) using new commercial diode laser technology at 2.68 microm, (3) LICOR NDIR analyzer and (4) flasks. LDS, LICOR and flasks measurements were made in the same location, LICOR and flasks being taken as reference. Horizontal HDIAL measurements of CO(2) absorption using aerosol backscatter signal are reported. Using new spectroscopic data in the 2 microm band and meteorological sensor measurements, a mean CO(2) mixing ratio is inferred by the HDIAL in a 1 km long path above the 15m height location of the CO(2) in situ sensors. We compare HDIAL and LDS measurements with the LICOR data for 30 min of time averaging. The mean standard deviation of the HDIAL and the LDS CO(2) mixing ratio results are 3.3 ppm and 0.89 ppm, respectively. The bias of the HDIAL and the LDS measurements are -0.54 ppm and -0.99 ppm, respectively.

  13. Dependently typed array programs don’t go wrong

    NARCIS (Netherlands)

    Trojahner, K.; Grelck, C.

    2009-01-01

    The array programming paradigm adopts multidimensional arrays as the fundamental data structures of computation. Array operations process entire arrays instead of just single elements. This makes array programs highly expressive and introduces data parallelism in a natural way. Array programming

  14. Dependently typed array programs don't go wrong

    NARCIS (Netherlands)

    Trojahner, K.; Grelck, C.

    2008-01-01

    The array programming paradigm adopts multidimensional arrays as the fundamental data structures of computation. Array operations process entire arrays instead of just single elements. This makes array programs highly expressive and introduces data parallelism in a natural way. Array programming

  15. Offering an Array of Improvements

    Science.gov (United States)

    2001-01-01

    Sensors Unlimited, Inc., with SBIR funding from NASA's Langley Research Center, Goddard Space Flight Center, Marshall Space Flight Center, and the Jet Propulsion Laboratory, developed a monolithic focal plane array for near-infrared imaging. The company developed one- (1- D) and two-dimensional (2-D) imaging arrays consisting of a highly reliable InGaAs p-I-n diode as a photodetector for monitoring a variety of applications, including single element device applications in receivers. The InGaAs 1-D and 2-D arrays have many applications. For example, they monitor the performance of dense wavelength division multiplexing (DWDM) systems- the process of packaging many channels into a single fiber-optic cable. Sensors Unlimited commercially offers its LXTM and LYTM Series InGaAs linear arrays for reliable DWDM performance monitoring. The LX and LY arrays enable instrument module designs with no moving parts, which provides for superior uniformity, and fast, linear outputs that remain stable over a wide temperature range. Innovative technologies derived from the monolithic focal plane array have enabled telecommunication companies to optimize existing bandwidth in their fiber-optic networks in order to support a high volume of network traffic. At the same time, the technologies obtained from the array have the potential for reducing costs, while increasing performance from Sensors Unlimited's current product lines.

  16. Efficient array design for sonotherapy

    Science.gov (United States)

    Stephens, Douglas N.; Kruse, Dustin E.; Ergun, Arif S.; Barnes, Stephen; Lu, X. Ming; Ferrara, Katherine W.

    2008-07-01

    New linear multi-row, multi-frequency arrays have been designed, constructed and tested as fully operational ultrasound probes to produce confocal imaging and therapeutic acoustic intensities with a standard commercial ultrasound imaging system. The triple-array probes and imaging system produce high quality B-mode images with a center row imaging array at 5.3 MHz and sufficient acoustic power with dual therapeutic arrays to produce mild hyperthermia at 1.54 MHz. The therapeutic array pair in the first probe design (termed G3) utilizes a high bandwidth and peak pressure, suitable for mechanical therapies. The second multi-array design (termed G4) has a redesigned therapeutic array pair which is optimized for a high time-averaged power output suitable for mild hyperthermia applications. The 'thermal therapy' design produces more than 4 W of acoustic power from the low-frequency arrays with only a 10.5 °C internal rise in temperature after 100 s of continuous use with an unmodified conventional imaging system or substantially longer operation at lower acoustic power. The low-frequency arrays in both probe designs were examined and contrasted for real power transfer efficiency with a KLM model which includes all lossy contributions in the power delivery path from system transmitters to the tissue load. Laboratory verification was successfully performed for the KLM-derived estimates of transducer parallel model acoustic resistance and dissipation resistance, which are the critical design factors for acoustic power output and undesired internal heating, respectively.

  17. Efficient array design for sonotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Stephens, Douglas N; Kruse, Dustin E; Ferrara, Katherine W [University of California, Davis, CA (United States); Ergun, Arif S; Barnes, Stephen [Siemens Corporate Research, Inc., Imaging and Visualization, 755 College Road East, Princeton, New Jersey 08540 (United States); Lu, X Ming [Siemens Medical Solutions, 22010 SE 51st Street, Issaquah, Washington 98029-7298 (United States)], E-mail: dnstephens@ucdavis.edu, E-mail: kwferrara@ucdavis.edu

    2008-07-21

    New linear multi-row, multi-frequency arrays have been designed, constructed and tested as fully operational ultrasound probes to produce confocal imaging and therapeutic acoustic intensities with a standard commercial ultrasound imaging system. The triple-array probes and imaging system produce high quality B-mode images with a center row imaging array at 5.3 MHz and sufficient acoustic power with dual therapeutic arrays to produce mild hyperthermia at 1.54 MHz. The therapeutic array pair in the first probe design (termed G3) utilizes a high bandwidth and peak pressure, suitable for mechanical therapies. The second multi-array design (termed G4) has a redesigned therapeutic array pair which is optimized for a high time-averaged power output suitable for mild hyperthermia applications. The 'thermal therapy' design produces more than 4 W of acoustic power from the low-frequency arrays with only a 10.5 deg. C internal rise in temperature after 100 s of continuous use with an unmodified conventional imaging system or substantially longer operation at lower acoustic power. The low-frequency arrays in both probe designs were examined and contrasted for real power transfer efficiency with a KLM model which includes all lossy contributions in the power delivery path from system transmitters to the tissue load. Laboratory verification was successfully performed for the KLM-derived estimates of transducer parallel model acoustic resistance and dissipation resistance, which are the critical design factors for acoustic power output and undesired internal heating, respectively.

  18. Broadband phased-arrays antennas

    Science.gov (United States)

    Mansky, L.

    1984-09-01

    The actual jamming-to-signal ratio achieved in an electronic countermeasures (ECM) system depends on the effective radiated power (ERP) directed toward the radar by the ECM system. The required ERP may be obtained in a phase-steered array using a variety of transmit-subsystem hardware configurations. Here, tradeoff criteria to aid in the selection of an optimal architecture are discussed. Such selection is based on minimizing the array size, backscattering cross selection, and overall system complexity. Functional elements of typical phased arrays and their principal components are descried.

  19. Pulse Dispersion in Phased Arrays

    Directory of Open Access Journals (Sweden)

    Randy L. Haupt

    2017-01-01

    Full Text Available Phased array antennas cause pulse dispersion when receiving or transmitting wideband signals, because phase shifting the signals does not align the pulse envelopes from the elements. This paper presents two forms of pulse dispersion that occur in a phased array antenna. The first results from the separation distance between the transmit and receive antennas and impacts the definition of far field in the time domain. The second is a function of beam scanning and array size. Time delay units placed at the element and/or subarrays limit the pulse dispersion.

  20. Fundamentals of ultrasonic phased arrays

    CERN Document Server

    Schmerr, Lester W

    2014-01-01

    This book describes in detail the physical and mathematical foundations of ultrasonic phased array measurements.?The book uses linear systems theory to develop a comprehensive model of the signals and images that can be formed with phased arrays. Engineers working in the field of ultrasonic nondestructive evaluation (NDE) will find in this approach a wealth of information on how to design, optimize and interpret ultrasonic inspections with phased arrays. The fundamentals and models described in the book will also be of significant interest to other fields, including the medical ultrasound and

  1. Antenna arrays a computational approach

    CERN Document Server

    Haupt, Randy L

    2010-01-01

    This book covers a wide range of antenna array topics that are becoming increasingly important in wireless applications, particularly in design and computer modeling. Signal processing and numerical modeling algorithms are explored, and MATLAB computer codes are provided for many of the design examples. Pictures of antenna arrays and components provided by industry and government sources are presented with explanations of how they work. Antenna Arrays is a valuable reference for practicing engineers and scientists in wireless communications, radar, and remote sensing, and an excellent textbook for advanced antenna courses.

  2. SQIF Arrays as RF Sensors (Briefing Charts)

    National Research Council Canada - National Science Library

    Yukon, Stanford P

    2007-01-01

    ... (Superconducting Quantum Interference Filter) arrays may be employed as sensitive RF sensors. RF SQIF arrays fabricated with high Tc Josephson junctions can be cooled with small Sterling microcoolers...

  3. TIMASSS: the IRAS 16293-2422 millimeter and submillimeter spectral survey. I. Observations, calibration, and analysis of the line kinematics

    Science.gov (United States)

    Caux, E.; Kahane, C.; Castets, A.; Coutens, A.; Ceccarelli, C.; Bacmann, A.; Bisschop, S.; Bottinelli, S.; Comito, C.; Helmich, F. P.; Lefloch, B.; Parise, B.; Schilke, P.; Tielens, A. G. G. M.; van Dishoeck, E.; Vastel, C.; Wakelam, V.; Walters, A.

    2011-08-01

    Context. Unbiased spectral surveys are powerful tools to study the chemistry and the physics of star forming regions, because they can provide a complete census of the molecular content and the observed lines probe the physical structure of the source. Aims: While unbiased surveys at the millimeter and sub-millimeter wavelengths observable from ground-based telescopes have previously been performed towards several high mass protostars, very little exists on low mass protostars, which are believed to resemble our own Sun's progenitor. To help fill up this gap in our understanding, we carried out a complete spectral survey of the bands at 3, 2, 1, and 0.9 mm towards the solar type protostar IRAS 16293-2422. Methods: The observations covered a range of about 200 GHz and were obtained with the IRAM-30 m and JCMT-15 m telescopes during about 300 h of observations. Particular attention was devoted to the inter-calibration of the acquired spectra with previous observations. All the lines detected with more than 3σ confidence-interval certainty and free from obvious blending effects were fitted with Gaussians to estimate their basic kinematic properties. Results: More than 4000 lines were detected (with σ ≥ 3) and identified, yielding a line density of approximatively 20 lines per GHz, comparable to previous surveys in massive hot cores. The vast majority (about two-thirds) of the lines are weak and produced by complex organic molecules. The analysis of the profiles of more than 1000 lines belonging to 70 species firmly establishes the presence of two distinct velocity components associated with the two objects, A and B, forming the IRAS 16293-2422 binary system. In the source A, the line widths of several species increase with the upper level energy of the transition, a behavior compatible with gas infalling towards a ~1 M⊙ object. The source B, which does not show this effect, might have a much lower central mass of ~0.1 M⊙. The difference in the rest velocities

  4. Fundamentals of spherical array processing

    CERN Document Server

    Rafaely, Boaz

    2015-01-01

    This book provides a comprehensive introduction to the theory and practice of spherical microphone arrays. It is written for graduate students, researchers and engineers who work with spherical microphone arrays in a wide range of applications.   The first two chapters provide the reader with the necessary mathematical and physical background, including an introduction to the spherical Fourier transform and the formulation of plane-wave sound fields in the spherical harmonic domain. The third chapter covers the theory of spatial sampling, employed when selecting the positions of microphones to sample sound pressure functions in space. Subsequent chapters present various spherical array configurations, including the popular rigid-sphere-based configuration. Beamforming (spatial filtering) in the spherical harmonics domain, including axis-symmetric beamforming, and the performance measures of directivity index and white noise gain are introduced, and a range of optimal beamformers for spherical arrays, includi...

  5. Monolithic phased arrays - Recent advances

    Science.gov (United States)

    Kinzel, Joseph A.

    1991-07-01

    Advances in monolithic phased array technology defined as a solid state array based on GaAs monolithic microwave integrated circuits are reviewed focusing on analytical and experimental work to improve array performance and reliability while reducing the cost. Monolithic array technology is equally applicable to communications and radar systems. In radar applications both transmit and receive functions at the elemental level require a transmit/receive module's physical size to be compatible with 1/2 wave length element spacing. For communication applications, separate aperture are used for transmit and receive to ensure sufficient isolation for full duplex operation. Radar transmitter chains are capable of operating with a saturated power output stage which helps to increase efficiency and minimize DC power. Communication systems place severe linearity constraints on the transmitters and receivers which requires the power amplifier to operate in an ultra-linear fashion.

  6. Thermopile Area Array Readout Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA/JPL thermopile detector linear arrays, wire bonded to Black Forest Engineering (BFE) CMOS readout integrated circuits (ROICs), have been utilized in NASA...

  7. Next Generation Microshutter Arrays Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop the next generation MicroShutter Array (MSA) as a multi-object field selector for missions anticipated in the next two decades. For many...

  8. Redundant arrays of IDE drives

    Science.gov (United States)

    Sanders, D. A.; Cremaldi, L. M.; Eschenburg, V.; Lawrence, C. N.; Riley, C.; Summers, D. J.; Petravick, D. L.

    2002-08-01

    The next generation of high-energy physics experiments is expected to gather prodigious amounts of data. New methods must be developed to handle this data and make analysis at universities possible. We examine some techniques that use recent developments in commodity hardware. We test redundant arrays of integrated drive electronics (IDE) disk drives for use in offline high-energy physics data analysis. IDE redundant array of inexpensive disks (RAID) arrays prices now equal the cost per terabyte of million dollar tape robots! The arrays can be scaled to sizes affordable to institutions without robots and used when fast random access at low cost is important. We also explore three methods of moving data between sites; internet transfers, hot pluggable IDE disks in FireWire cases, and writable digital video disks (DVD-R) disks.

  9. Integrated Spatial Filter Array Project

    Data.gov (United States)

    National Aeronautics and Space Administration — To address the NASA Earth Science Division need for spatial filter arrays for amplitude and wavefront control, Luminit proposes to develop a novel Integrated Spatial...

  10. Biologically Assembled Quantum Electronic Arrays

    Science.gov (United States)

    2013-06-07

    Salve Regina, 2010. N. Seeman, James W. Canary 50th Birthday Symposium, New York, 2010. N. Seeman, CNIC 2010, Havana , 2010. N. Seeman, Kavli Prize Lecture...electron tunneling steps in the current-voltage characteristics of linear arrays of gold nanopaarticles assembled by 2D DNA scaffolding. In the...nanomechanical devices (1999). In conjunction with the Kiehl laboratory, the Seeman laboratory was involved in organizing gold nanoparticles in 2D arrays

  11. True-time-delay photonic beamformer for an L-band phased array radar

    Science.gov (United States)

    Zmuda, Henry; Toughlian, Edward N.; Payson, Paul M.; Malowicki, John E.

    1995-10-01

    The problem of obtaining a true-time-delay photonic beamformer has recently been a topic of great interest. Many interesting and novel approaches to this problem have been studied. This paper examines the design, construction, and testing of a dynamic optical processor for the control of a 20-element phased array antenna operating at L-band (1.2-1.4 GHz). The approach taken here has several distinct advantages. The actual optical control is accomplished with a class of spatial light modulator known as a segmented mirror device (SMD). This allows for the possibility of controlling an extremely large number (tens of thousands) of antenna elements using integrated circuit technology. The SMD technology is driven by the HDTV and laser printer markets so ultimate cost reduction as well as technological improvements are expected. Optical splitting is efficiently accomplished using a diffractive optical element. This again has the potential for use in antenna array systems with a large number of radiating elements. The actual time delay is achieved using a single acousto-optic device for all the array elements. Acousto-optic device technologies offer sufficient delay as needed for a time steered array. The topological configuration is an optical heterodyne system, hence high, potentially millimeter wave center frequencies are possible by mixing two lasers of slightly differing frequencies. Finally, the entire system is spatially integrated into a 3D glass substrate. The integrated system provides the ruggedness needed in most applications and essentially eliminates the drift problems associated with free space optical systems. Though the system is presently being configured as a beamformer, it has the ability to operate as a general photonic signal processing element in an adaptive (reconfigurable) transversal frequency filter configuration. Such systems are widely applicable in jammer/noise canceling systems, broadband ISDN, and for spread spectrum secure communications

  12. Field Results from Three Campaigns to Validate the Performance of the Miniaturized Laser Heterodyne Radiometer (Mini-LHR) for Measuring Carbon Dioxide and Methane in the Atmospheric Column

    Science.gov (United States)

    Miller, J. Houston; Clarke, Greg B.; Melroy, Hilary; Ott, Lesley; Steel, Emily Wilson

    2014-01-01

    In a collaboration between NASA GSFC and GWU, a low-cost, surface instrument is being developed that can continuously monitor key carbon cycle gases in the atmospheric column: carbon dioxide (CO2) and methane (CH4). The instrument is based on a miniaturized, laser heterodyne radiometer (LHR) using near infrared (NIR) telecom lasers. Despite relatively weak absorption line strengths in this spectral region, spectrallyresolved atmospheric column absorptions for these two molecules fall in the range of 60-80% and thus sensitive and precise measurements of column concentrations are possible. In the last year, the instrument was deployed for field measurements at Park Falls, Wisconsin; Castle Airport near Atwater, California; and at the NOAA Mauna Loa Observatory in Hawaii. For each subsequent campaign, improvement in the figures of merit for the instrument has been observed. In the latest work the absorbance noise is approaching 0.002 optical density (OD) noise on a 1.8 OD signal. An overview of the measurement campaigns and the data retrieval algorithm for the calculation of column concentrations will be presented. For light transmission through the atmosphere, it is necessary to account for variation of pressure, temperature, composition, and refractive index through the atmosphere that are all functions of latitude, longitude, time of day, altitude, etc. For temperature, pressure, and humidity profiles with altitude we use the Modern-Era Retrospective Analysis for Research and Applications (MERRA) data. Spectral simulation is accomplished by integrating short-path segments along the trajectory using the SpecSyn spectral simulation suite developed at GW. Column concentrations are extracted by minimizing residuals between observed and modeled spectrum using the Nelder-Mead simplex algorithm. We will also present an assessment of uncertainty in the reported concentrations from assumptions made in the meteorological data, LHR instrument and tracker noise, and radio

  13. Millimeter and submillimeter wave ESR measurement of Ho{sub 2}Cu{sub 2}O{sub 5} aligned powder sample

    Energy Technology Data Exchange (ETDEWEB)

    Okubo, S. [Kobe Univ., Graduate School of Science and Technology, Kobe, Hyogo (Japan); Goto, T.; Tanaka, T.; Ohta, H. [Kobe Univ. (Japan). Dept. of Physics; Mogi, I.; Watanabe, K.; Motokawa, M. [Tohoku Univ., Sendai (Japan). Inst. for Materials Research

    1999-07-01

    To gain information of anisotropy of Ho{sub 2}Cu{sub 2}O{sub 5} the aligned powder sample was prepared under the static high magnetic field of 5T. Millimeter and submillimeter wave ESR measurements of aligned Ho{sub 2}Cu{sub 2}O{sub 5} samples have been performed for the first time in the frequency region from 50 to 430 GHz using the pulsed magnetic field up to 16T at 1.8K. Antiferromagnetic resonances were observed clearly at 1.8K. AFMR modes of easy axis change at two critical fields. The temperature dependence measurements were also performed and the Neel temperature of the system is discussed. (author)

  14. Scanning SQUID microscopy as a new tool for sub-millimeter scale magnetostratigraphy: An application to unveil the growth process of marine ferromanganese crusts and its future potential

    Science.gov (United States)

    Oda, H.; Noguchi, A.; Yamamoto, Y.; Usui, A.; Sato, M.; Kawai, J.

    2016-12-01

    Scanning SQUID microscope, a new developing tool for paleomagnetists, enables us to map magnetic field on surfaces of geological samples or thin sections at sub-millimeter scale and provides opportunity to conduct magnetostratigraphy with an unprecedented resolution. In the presentation, we show an example of sub-millimeter scale magnetostratigraphy with a newly developed scanning SQUID (superconducting quantum interference device) microscope (SSM) at Geological Survey, AIST (Kawai et al., 2016; Oda et al., submitted). Marine ferromanganese crusts grow very slowly throughout the global ocean by direct precipitation typically on seamounts for more than several tens of millions of years, which can be considered as archives of paleoclimate and paleoceanography.In order to uncover the history of paleoenvironment recorded in the ferromanganese cursts, it is very important to provide their reliable age models and growth rates. Previous studies have shown universal applicability of magnetostratigraphy in estimating growth ages of ferromanganese crust (Oda et al., 2011; Noguchi et al., in press). A thin section of a ferromanganese crust sample from Takuyo-Daigo seamount in northwest Pacific was used for the mapping of magnetic field with the SSM, where minimum amount of dust and sediment are expected to come from continents. The result shows that average growth rate of the ferromanganese crust from this seamount is 3.56 ± mm/m.y., which is within 17.6% of that deduced from the 10Be/9Be dating method (2.93 ±0.15 mm/m.y.). Although the mechanism of remanent magnetization acquisition for ferromanganese crusts need to be investigated further, the magnetic stripes parallel to the growth pattern observed on optical and backscattered electron images promises the future possibilities to provide a quick tool to estimate ages and growth rates for ferromanganese crusts. Finally, it can be concluded that SSM could be a fundamental tool for paleomagnetists in providing avenue to

  15. TU-H-CAMPUS-TeP2-03: High Sensitivity and High Resolution Fiber Based Micro-Detector for Sub-Millimeter Preclinical Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Izaguirre, E; Pokhrel, S; Knewtson, T [University of Tennessee Medical Science Center, Memphis, TN (United States); University of Missouri, Columbia, MO (United States); Hedrick, S [Provision Center for Proton Therapy, Knoxville, TN (United States)

    2016-06-15

    Purpose: Current precision of small animal and cell micro-irradiators has continuously increased during the past years. Currently, preclinical irradiators can deliver sub-millimeter fields with micrometric precision but there are no water equivalent dosimeters to determine small field profiles and dose in the orthovoltage range of energies with micrometric resolution and precision. We have developed a fiber based micro-dosimeter with the resolution and dosimetric accuracy required for radiobiological research. Methods: We constructed two prototypes of micro-dosimeters based on different compositions of fiber scintillators to study the spatial resolution and dosimetric precision of small animal and cell micro-irradiators. The first has green output and the second has blue output. The blue output dosimeter has the highest sensitivity because it matches the spectral sensitivity of silicon photomultipliers. A blue detector with 500um cross section was built and tested respect to a CC01 ion chamber, film, and the 1500um green output detector. Orthovoltage fields from 1×1mm2 to 5×5mm2 were used for detector characteristics comparison. Results: The blue fiber dosimeter shows great agreement with films and matches dose measurements with the gold-standard ion chamber for 5×5mm2 fields. The detector has the appropriate sensitivity to measure fields from 1×1mm2 to larger sizes with a 1% dosimetric accuracy. The spatial resolution is in the sub-millimeter range and the spectral matching with the photomultiplier allows reducing the sensor cross section even further than the presented prototype. These results suggest that scintillating fibers combined with silicon photomultipliers is the appropriate technology to pursue micro-dosimetry for small animals and disperse cell samples. Conclusion: The constructed detectors establish a new landmark for the resolution and sensitivity of fiber based microdetectors. The validation of the detector in our small animal and cell

  16. Retrieval of Mir Solar Array

    Science.gov (United States)

    Rutledge, Sharon K.; deGroh, Kim K.

    1999-01-01

    A Russian solar array panel removed in November 1997 from the non-articulating photovoltaic array on the Mir core module was returned to Earth on STS-89 in January 1998. The panel had been exposed to low Earth orbit (LEO) for 10 years prior to retrieval. The retrieval provided a unique opportunity to study the effects of the LEO environment on a functional solar array. To take advantage of this opportunity, a team composed of members from RSC-Energia (Russia), the Boeing Company, and the following NASA Centers--Johnson Space Center, Kennedy Space Center, Langley Research Center, Marshall Space Flight Center, and Lewis Research Center--was put together to analyze the array. After post-retrieval inspections at the Spacehab Facility at Kennedy in Florida, the array was shipped to Lewis in Cleveland for electrical performance tests, closeup photodocumentation, and removal of selected solar cells and blanket material. With approval from RSC-Energia, five cell pairs and their accompanying blanket and mesh material, and samples of painted handrail materials were selected for removal on the basis of their ability to provide degradation information. Sites were selected that provided different sizes and shapes of micrometeoroid impacts and different levels of surface contamination. These materials were then distributed among the team for round robin testing.

  17. Successive Standardization of Rectangular Arrays

    Directory of Open Access Journals (Sweden)

    Richard A. Olshen

    2012-02-01

    Full Text Available In this note we illustrate and develop further with mathematics and examples, the work on successive standardization (or normalization that is studied earlier by the same authors in [1] and [2]. Thus, we deal with successive iterations applied to rectangular arrays of numbers, where to avoid technical difficulties an array has at least three rows and at least three columns. Without loss, an iteration begins with operations on columns: first subtract the mean of each column; then divide by its standard deviation. The iteration continues with the same two operations done successively for rows. These four operations applied in sequence completes one iteration. One then iterates again, and again, and again, ... In [1] it was argued that if arrays are made up of real numbers, then the set for which convergence of these successive iterations fails has Lebesgue measure 0. The limiting array has row and column means 0, row and column standard deviations 1. A basic result on convergence given in [1] is true, though the argument in [1] is faulty. The result is stated in the form of a theorem here, and the argument for the theorem is correct. Moreover, many graphics given in [1] suggest that except for a set of entries of any array with Lebesgue measure 0, convergence is very rapid, eventually exponentially fast in the number of iterations. Because we learned this set of rules from Bradley Efron, we call it “Efron’s algorithm”. More importantly, the rapidity of convergence is illustrated by numerical examples.

  18. Integrated Array/Metadata Analytics

    Science.gov (United States)

    Misev, Dimitar; Baumann, Peter

    2015-04-01

    Data comes in various forms and types, and integration usually presents a problem that is often simply ignored and solved with ad-hoc solutions. Multidimensional arrays are an ubiquitous data type, that we find at the core of virtually all science and engineering domains, as sensor, model, image, statistics data. Naturally, arrays are richly described by and intertwined with additional metadata (alphanumeric relational data, XML, JSON, etc). Database systems, however, a fundamental building block of what we call "Big Data", lack adequate support for modelling and expressing these array data/metadata relationships. Array analytics is hence quite primitive or non-existent at all in modern relational DBMS. Recognizing this, we extended SQL with a new SQL/MDA part seamlessly integrating multidimensional array analytics into the standard database query language. We demonstrate the benefits of SQL/MDA with real-world examples executed in ASQLDB, an open-source mediator system based on HSQLDB and rasdaman, that already implements SQL/MDA.

  19. Nonlinear Array System Modeler for Advanced Array Calibration

    Science.gov (United States)

    2017-03-01

    arri re 1. A cartoo ces common in Array Ca ill work in iso ese elements t erform high-l out worrying a ture. e of having the is that it allow f...he band of causes the number of m the mix- ted, as ex- erer cannot (though it lting from ! 660 Future Work At this point the test moves to

  20. Versatile Flexible Graphene Multielectrode Arrays.

    Science.gov (United States)

    Kireev, Dmitry; Seyock, Silke; Ernst, Mathis; Maybeck, Vanessa; Wolfrum, Bernhard; Offenhäusser, Andreas

    2016-12-23

    Graphene is a promising material possessing features relevant to bioelectronics applications. Graphene microelectrodes (GMEAs), which are fabricated in a dense array on a flexible polyimide substrate, were investigated in this work for their performance via electrical impedance spectroscopy. Biocompatibility and suitability of the GMEAs for extracellular recordings were tested by measuring electrical activities from acute heart tissue and cardiac muscle cells. The recordings show encouraging signal-to-noise ratios of 65 ± 15 for heart tissue recordings and 20 ± 10 for HL-1 cells. Considering the low noise and excellent robustness of the devices, the sensor arrays are suitable for diverse and biologically relevant applications.