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Sample records for squid array lisa

  1. Radiation detection from phase-locked serial dc SQUID arrays

    DEFF Research Database (Denmark)

    Kaplunenko, V. K.; Mygind, Jesper; Pedersen, Niels Falsig

    1993-01-01

    We report on synchronous operation of series arrays of inductively coupled superconducting quantum interference devices (SQUIDs). Each array consisted of N=3 or 11 dc SQUIDs with common inductances providing a strong interaction between neighboring cells. Externally shunted (betac[approximately-e......We report on synchronous operation of series arrays of inductively coupled superconducting quantum interference devices (SQUIDs). Each array consisted of N=3 or 11 dc SQUIDs with common inductances providing a strong interaction between neighboring cells. Externally shunted (betac...

  2. SQUID readout multiplexers for transition-edge sensor arrays

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Adrian T. [Physics Department, University of California, Berkeley, CA 94720 (United States) and Physics Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)]. E-mail: atl@physics.berkeley.edu

    2006-04-15

    Two classes of SQUID multiplexer are being developed for large arrays of cryogenic sensors, distinguished by their operation in either the time domain or frequency domain. Several systems optimized for use with Transition-Edge Sensors (TES) are reaching a high level of maturity, and will be deployed on funded astrophysics experiments in the next several years. A useful technical figure of merit is the product of the number of detectors multplexed multipled by the bandwidth of the detectors, which can be termed the 'total signal bandwidth' of a multiplexer system. This figure of merit is comparable within a factor of two for the mature systems. Several new concepts for increasing the total bandwidth are being developed in the broad class of frequency domain multiplexers. Another notable area of progress is in the level of integration of muliplexer and detector array. The time domain system for SCUBA-II is a sophisticated bump-bonded sandwich structure, and the Jena/MPI group is integrating detectors and a time domain multiplexer on one substrate. Finally, the Kinetic Inductance Detectors (KID)/HEMT (non-SQUID) detector/multiplexer system, will be discussed briefly.

  3. Advancements of the Lightweight Integrated Solar Array and Transceiver (LISA-T) Small Spacecraft System

    Science.gov (United States)

    Lockett, Tiffany Russell; Martinez, Armando; Boyd, Darren; SanSouice, Michael; Farmer, Brandon; Schneider, Todd; Laue, Greg; Fabisinski, Leo; Johnson, Les; Carr, John A.

    2015-01-01

    This paper describes recent advancements of the Lightweight Integrated Solar Array and Transceiver (LISA-T) currently being developed at NASA's Marshall Space Flight Center. The LISA-T array comprises a launch stowed, orbit deployed structure on which thin-film photovoltaic (PV) and antenna devices are embedded. The system provides significant electrical power generation at low weights, high stowage efficiency, and without the need for solar tracking. Leveraging high-volume terrestrial-market PVs also gives the potential for lower array costs. LISA-T is addressing the power starvation epidemic currently seen by many small-scale satellites while also enabling the application of deployable antenna arrays. Herein, an overview of the system and its applications are presented alongside sub-system development progress and environmental testing plans.

  4. Multichannel DC SQUID sensor array for biomagnetic applications

    International Nuclear Information System (INIS)

    Hoenig, H.E.; Daalmans, G.M.; Bar, L.; Bommel, F.; Paulus, A.; Uhl, D.; Weisse, H.J.; Schneider, S.; Seifert, H.; Reichenberger, H.; Abraham-Fuchs, K.

    1991-01-01

    This paper reports on a biomagnetic multichannel system for medical diagnosis of brain and heart KRENIKON has been developed. 37 axial 2st order gradiometers - manufactured as flexible superconducting printed circuits - are arranged in a circular flat array of 19 cm diameter. Additionally, 3 orthogonal magnetometers are provided. The DC SQUIDs are fabricated in all-Nb technology, ten on a chip. The sensor system is operated in a shielded room with two layers of soft magnetic material and one layer of Al. The every day noise level is 10 fT/Hz 1/2 at frequencies above 10 Hz. Within 2 years of operation in a normal urban surrounding, useful clinical applications have been demonstrated (e.g. for epilepsy and heart arrhythmias)

  5. Flux-coherent series SQUID array magnetometers operating above 77 K with superior white flux noise than single-SQUIDs at 4.2 K

    Science.gov (United States)

    Chesca, Boris; John, Daniel; Mellor, Christopher J.

    2015-10-01

    A very promising direction to improve the sensitivity of magnetometers based on superconducting quantum interference devices (SQUIDs) is to build a series-array of N non-interacting SQUIDs operating flux-coherently, because in this case their voltage modulation depth, ΔV, linearly scales with N whereas the white flux noise SΦ1/2 decreases as 1/N1/2. Here, we report the realization of both these improvements in an advanced layout of very large SQUID arrays made of YBa2Cu3O7. Specially designed with large area narrow flux focusers for increased field sensitivity and improved flux-coherency, our arrays have extremely low values for SΦ1/2 between (0.25 and 0.44) μΦ0/Hz1/2 for temperatures in the range (77-83) K. In this respect, they outperform niobium/aluminium trilayer technology-based single-SQUIDs operating at 4.2 K. Moreover, with values for ΔV and transimpedance in the range of (10-17) mV and (0.3-2.5) kΩ, respectively, a direct connection to a low-noise room temperature amplifier is allowed, while matching for such readout is simplified and the available bandwidth is greatly increased. These landmark performances suggest such series SQUID arrays are ideal candidates to replace single-SQUIDs operating at 4.2 K in many applications.

  6. Design and Performance of the Multiplexed SQUID/TES Array at Ninety Gigahertz

    Science.gov (United States)

    Stanchfield, Sara; Ade, Peter; Aguirre, James; Brevik, Justus A.; Cho, Hsiao-Mei; Datta, Rahul; Devlin, Mark; Dicker, Simon R.; Dober, Bradley; Duff, Shannon M.; Egan, Dennis; Ford, Pam; Hilton, Gene; Hubmayr, Johannes; Irwin, Kent; Knowles, Kenda; Marganian, Paul; Mason, Brian Scott; Mates, John A. B.; McMahon, Jeff; Mello, Melinda; Mroczkowski, Tony; Romero, Charles; Sievers, Jonathon; Tucker, Carole; Vale, Leila R.; Vissers, Michael; White, Steven; Whitehead, Mark; Ullom, Joel; Young, Alexander

    2018-01-01

    We present the array performance and astronomical images from early science results from MUSTANG-2, a 90 GHz feedhorn-coupled, microwave SQUID-multiplexed TES bolometer array operating on the Robert C. Byrd Green Bank Telescope (GBT). MUSTANG-2 was installed on the GBT on December 2, 2016 and immediately began commissioning efforts, followed by science observations, which are expected to conclude June 2017. The feedhorn and waveguide-probe-coupled detector technology is a mature technology, which has been used on instrument including the South Pole Telescope, the Atacama Cosmology Telescope, and the Atacama B-mode Search telescope. The microwave SQUID readout system developed for MUSTANG-2 currently reads out 66 detectors with a single coaxial cable and will eventually allow thousands of detectors to be multiplexed. This microwave SQUID multiplexer combines the proven abilities of millimeterwave TES detectors with the multiplexing capabilities of KIDs with no degradation in noise performance of the detectors. Each multiplexing device is read out using warm electronics consisting of a commercially available ROACH board, a DAC/ADC card, and an Intermediate Frequency mixer circuit. The hardware was originally developed by the UC Berkeley Collaboration for Astronomy Signal Processing and Electronic Research (CASPER) group, whose primary goal is to develop scalable FPGA-based hardware with the flexibility to be used in a wide range of radio signal processing applications. MUSTANG-2 is the first on-sky instrument to use microwave SQUID multiplexing and is available as a shared-risk/PI instrument on the GBT. In MUSTANG-2's first season 7 separate proposals were awarded a total of 230 hours of telescope time.

  7. SQUID (superconducting quantum interference device) arrays for simultaneous magnetic measurements: Calibration and source localization performance

    Science.gov (United States)

    Kaufman, Lloyd; Williamson, Samuel J.; Costaribeiro, P.

    1988-02-01

    Recently developed small arrays of SQUID-based magnetic sensors can, if appropriately placed, locate the position of a confined biomagnetic source without moving the array. The authors present a technique with a relative accuracy of about 2 percent for calibrating such sensors having detection coils with the geometry of a second-order gradiometer. The effects of calibration error and magnetic noise on the accuracy of locating an equivalent current dipole source in the human brain are investigated for 5- and 7-sensor probes and for a pair of 7-sensor probes. With a noise level of 5 percent of peak signal, uncertainties of about 20 percent in source strength and depth for a 5-sensor probe are reduced to 8 percent for a pair of 7-sensor probes, and uncertainties of about 15 mm in lateral position are reduced to 1 mm, for the configuration considered.

  8. Flux-coherent series SQUID array magnetometers operating above 77 K with superior white flux noise than single-SQUIDs at 4.2 K

    International Nuclear Information System (INIS)

    Chesca, Boris; John, Daniel; Mellor, Christopher J.

    2015-01-01

    A very promising direction to improve the sensitivity of magnetometers based on superconducting quantum interference devices (SQUIDs) is to build a series-array of N non-interacting SQUIDs operating flux-coherently, because in this case their voltage modulation depth, ΔV, linearly scales with N whereas the white flux noise S Φ 1/2 decreases as 1/N 1/2 . Here, we report the realization of both these improvements in an advanced layout of very large SQUID arrays made of YBa 2 Cu 3 O 7 . Specially designed with large area narrow flux focusers for increased field sensitivity and improved flux-coherency, our arrays have extremely low values for S Φ 1/2 between (0.25 and 0.44) μΦ 0 /Hz 1/2 for temperatures in the range (77–83) K. In this respect, they outperform niobium/aluminium trilayer technology-based single-SQUIDs operating at 4.2 K. Moreover, with values for ΔV and transimpedance in the range of (10–17) mV and (0.3–2.5) kΩ, respectively, a direct connection to a low-noise room temperature amplifier is allowed, while matching for such readout is simplified and the available bandwidth is greatly increased. These landmark performances suggest such series SQUID arrays are ideal candidates to replace single-SQUIDs operating at 4.2 K in many applications

  9. Reconstructing 3D profiles of flux distribution in array of unshunted Josephson junctions from 2D scanning SQUID microscope images

    International Nuclear Information System (INIS)

    Nascimento, F.M.; Sergeenkov, S.; Araujo-Moreira, F.M.

    2012-01-01

    By using a specially designed algorithm (based on utilizing the so-called Hierarchical Data Format), we report on successful reconstruction of 3D profiles of local flux distribution within artificially prepared arrays of unshunted Nb-AlO x -Nb Josephson junctions from 2D surface images obtained via the scanning SQUID microscope. The analysis of the obtained results suggest that for large sweep areas, the local flux distribution significantly deviates from the conventional picture and exhibits a more complicated avalanche-type behavior with a prominent dendritic structure. -- Highlights: ► The penetration of external magnetic field into an array of Nb-AlO x -Nb Josephson junctions is studied. ► Using Scanning SQUID Microscope, 2D images of local flux distribution within array are obtained. ► Using specially designed pattern recognition algorithm, 3D flux profiles are reconstructed from 2D images.

  10. Coherent arrays of planar dc-SQUIDS based on thin-film Josephson microbridges

    International Nuclear Information System (INIS)

    Hansen, J.B.

    1982-01-01

    Phase-locking and voltage-locking in systems consisting of two planar dc-SQUIDs located close together in the same superconducting film have been investigated. The locking strength was found to be strongly dependent on the fluxoid state of both SQUIDs. A simple model for the inductive coupling between two such dc-SQUIDs is presented and the prediction of the model is compared with the experimental results. (Auth.)

  11. Radio frequency interference noise reduction using a field programmable gate array for SQUID applications

    International Nuclear Information System (INIS)

    Sakuta, K; Narita, Y; Itozaki, H

    2007-01-01

    It is important to remove large environmental noise in superconducting quantum interference device (SQUID) measurement without magnetic shielding. Active noise control (ANC) is one of the effective methods to reduce environmental noise. Recently, SQUIDs have been used in various applications at high frequencies, such as nuclear quadrupole resonance (NQR). The NQR frequency from explosives is in the range 0.5-5 MHz. In this case, an NQR sensor is exposed to AM radio frequency interference (RFI). The feasibility of the ANC system for RFI that used digital signal processing was studied. Our investigation showed that this digital ANC system can be applied to SQUID measurements for RFI suppression

  12. Flux-coherent series SQUID array magnetometers operating above 77 K with superior white flux noise than single-SQUIDs at 4.2 K

    Energy Technology Data Exchange (ETDEWEB)

    Chesca, Boris, E-mail: B.Chesca@lboro.ac.uk; John, Daniel [Department of Physics, Loughborough University, Loughborough LE11 3TU (United Kingdom); Mellor, Christopher J. [School of Physics and Astronomy, Nottingham University, Nottingham NG7 2RD (United Kingdom)

    2015-10-19

    A very promising direction to improve the sensitivity of magnetometers based on superconducting quantum interference devices (SQUIDs) is to build a series-array of N non-interacting SQUIDs operating flux-coherently, because in this case their voltage modulation depth, ΔV, linearly scales with N whereas the white flux noise S{sub Φ}{sup 1/2} decreases as 1/N{sup 1/2}. Here, we report the realization of both these improvements in an advanced layout of very large SQUID arrays made of YBa{sub 2}Cu{sub 3}O{sub 7}. Specially designed with large area narrow flux focusers for increased field sensitivity and improved flux-coherency, our arrays have extremely low values for S{sub Φ}{sup 1/2} between (0.25 and 0.44) μΦ{sub 0}/Hz{sup 1/2} for temperatures in the range (77–83) K. In this respect, they outperform niobium/aluminium trilayer technology-based single-SQUIDs operating at 4.2 K. Moreover, with values for ΔV and transimpedance in the range of (10–17) mV and (0.3–2.5) kΩ, respectively, a direct connection to a low-noise room temperature amplifier is allowed, while matching for such readout is simplified and the available bandwidth is greatly increased. These landmark performances suggest such series SQUID arrays are ideal candidates to replace single-SQUIDs operating at 4.2 K in many applications.

  13. Rightsizing LISA

    International Nuclear Information System (INIS)

    Stebbins, R T

    2009-01-01

    The Laser Interferometer Space Antenna (LISA) science requirements and conceptual design have been fairly stable for over a decade. In the interest of reducing costs, the LISA Project at NASA has looked for simplifications of the architecture, at downsizing of subsystems and at descopes of the entire mission. This is a natural activity of the formulation phase and one that is particularly timely in the current NASA budgetary context. There is, and will continue to be, enormous pressure for cost reduction from both ESA and NASA, reviewers and the broader research community. Here, the rationale for the baseline architecture is reviewed, and recent efforts to find simplifications and other reductions that might lead to savings are reported. A few possible simplifications have been found in the LISA baseline architecture. In the interest of exploring cost sensitivity, one moderate and one aggressive descope have been evaluated; the cost savings are modest and the loss of science is not.

  14. Synthetic LISA: Simulating time delay interferometry in a model LISA

    International Nuclear Information System (INIS)

    Vallisneri, Michele

    2005-01-01

    We report on three numerical experiments on the implementation of Time-Delay Interferometry (TDI) for LISA, performed with Synthetic LISA, a C++/Python package that we developed to simulate the LISA science process at the level of scientific and technical requirements. Specifically, we study the laser-noise residuals left by first-generation TDI when the LISA armlengths have a realistic time dependence; we characterize the armlength-measurement accuracies that are needed to have effective laser-noise cancellation in both first- and second-generation TDI; and we estimate the quantization and telemetry bitdepth needed for the phase measurements. Synthetic LISA generates synthetic time series of the LISA fundamental noises, as filtered through all the TDI observables; it also provides a streamlined module to compute the TDI responses to gravitational waves according to a full model of TDI, including the motion of the LISA array and the temporal and directional dependence of the armlengths. We discuss the theoretical model that underlies the simulation, its implementation, and its use in future investigations on system-characterization and data-analysis prototyping for LISA

  15. The LISA Pathfinder Mission

    International Nuclear Information System (INIS)

    Armano, M; Audley, H; Born, M; Danzmann, K; Diepholz, I; Auger, G; Binetruy, P; Baird, J; Bortoluzzi, D; Brandt, N; Fitzsimons, E; Bursi, A; Caleno, M; Cavalleri, A; Cesarini, A; Dolesi, R; Ferroni, V; Cruise, M; Dunbar, N; Ferraioli, L

    2015-01-01

    LISA Pathfinder (LPF), the second of the European Space Agency's Small Missions for Advanced Research in Technology (SMART), is a dedicated technology validation mission for future spaceborne gravitational wave detectors, such as the proposed eLISA mission. LISA Pathfinder, and its scientific payload - the LISA Technology Package - will test, in flight, the critical technologies required for low frequency gravitational wave detection: it will put two test masses in a near-perfect gravitational free-fall and control and measure their motion with unprecedented accuracy. This is achieved through technology comprising inertial sensors, high precision laser metrology, drag-free control and an ultra-precise micro-Newton propulsion system. LISA Pathfinder is due to be launched in mid-2015, with first results on the performance of the system being available 6 months thereafter.The paper introduces the LISA Pathfinder mission, followed by an explanation of the physical principles of measurement concept and associated hardware. We then provide a detailed discussion of the LISA Technology Package, including both the inertial sensor and interferometric readout. As we approach the launch of the LISA Pathfinder, the focus of the development is shifting towards the science operations and data analysis - this is described in the final section of the paper (paper)

  16. LISA system design highlights

    Energy Technology Data Exchange (ETDEWEB)

    Sallusti, M [European Space Agency, ESTEC, Keplerlaan 1, 2200 AG Noordwijk ZH (Netherlands); Gath, P; Weise, D; Berger, M; Schulte, H R, E-mail: marcello.sallusti@esa.in, E-mail: peter.gath@astrium.eads.ne, E-mail: dennis.weise@astrium.eads.ne, E-mail: marcel.berger@astrium.eads.ne, E-mail: Hans.Reiner.Schulte@astrium.eads.ne [Astrium GmbH Satellites, Claude-Dornier-Str., 88039 Friedrichshafen (Germany)

    2009-05-07

    A contract, started in January 2005, was awarded to a consortium of Astrium GmbH and Astrium Ltd for the LISA Mission Formulation. The scope of the contract was the development of a reference design for the mission architecture and for the mission elements (with particular focus on the payload) and a successive phase of derivation of requirements, to be concluded with a mission design review. The technical starting point was the output of the previous LISA study formalized in the Final Technical Report, issued in the year 2000. During the design phase, different architecture concepts were identified and traded off, including the LISA orbits, the measurement scheme and the opto-mechanical architecture. During the Mission Design Review (July 2008) the consolidated mission baseline design, and the specifications of the flight elements and of the payload subsystem and major components were presented. This paper gives a brief overview of the major design points of the latest design of the LISA system.

  17. LISA system design highlights

    International Nuclear Information System (INIS)

    Sallusti, M; Gath, P; Weise, D; Berger, M; Schulte, H R

    2009-01-01

    A contract, started in January 2005, was awarded to a consortium of Astrium GmbH and Astrium Ltd for the LISA Mission Formulation. The scope of the contract was the development of a reference design for the mission architecture and for the mission elements (with particular focus on the payload) and a successive phase of derivation of requirements, to be concluded with a mission design review. The technical starting point was the output of the previous LISA study formalized in the Final Technical Report, issued in the year 2000. During the design phase, different architecture concepts were identified and traded off, including the LISA orbits, the measurement scheme and the opto-mechanical architecture. During the Mission Design Review (July 2008) the consolidated mission baseline design, and the specifications of the flight elements and of the payload subsystem and major components were presented. This paper gives a brief overview of the major design points of the latest design of the LISA system.

  18. LISA Pathfinder and eLISA news

    Science.gov (United States)

    Thorpe, James Ira; Mueller, Guido

    2014-01-01

    Two important gatherings of the space-based gravitational-wave detector community were held in Zurich, Switzerland this past March. The first was a meeting of the Science Working Team for LISA Pathfinder (LPF), a dedicated technology demonstrator mission for a future LISA-like gravitational wave observatory. LPF is entering an extremely exciting phase with launch less than 15 months away. All flight components for both the European science payload, known as the LISA Technology Package (LTP), and the NASA science payload, known as the Space Technology 7 Disturbance Reduction System (ST7-DRS), have been delivered and are undergoing integration. The final flight component for the spacecraft bus, a cold-gas thruster based on the successful GAIA design, will be delivered later this year. Current focus is on completing integration of the science payload (see Figures 1 and 2) and preparation for operations and data analysis. After a launch in Summer 2015, LPF will take approximately 90 days to reach its operational orbit around the Earth-Sun Lagrange point (L1), where it will begin science operations. After 90 days of LTP operations followed by 90 days of DRS operations, LPF will have completed its prime mission of paving the way for a space-based observatory of gravitational waves in the milliHertz band. Immediately following the meeting of the LPF team, the eLISA consortium held its third progress meeting. The consortium (www.elisascience.org) is the organizing body of the European space-based gravitational-wave community, and it was responsible for the "The Gravitational Universe" whitepaper that resulted in the November 2013 election of a gravitational-wave science theme for ESA's Cosmic Visions L3 opportunity. In preparation for an L3 mission concept call, which is expected later this decade, and for launch in the mid 2030s, the eLISA consortium members are coordinating technology development and mission study activities which will build on the LPF results. The final

  19. Review of SQUID Sensors for Measuring Magnetocardiography

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Y. H.; Kim, J. M.; Yu, K. K.; Kim, K.; Kwon, H. [Brain and Cognition Measurement Lab, Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of)

    2011-08-15

    Measurement of magnetic signals generated from electric activity of myocardium provides useful information for the functional diagnosis of heart diseases. Key technical component of the magnetocardiography (MCG) technology is SQUID. To measure MCG signals with high signal-to-noise ratio, sensitive SQUID magnetic field sensors are needed. Present magnetic field sensors based on Nb SQUIDs have field sensitivity good enough to measure most of MCG signals. However, for accurate measurement of fine signal pattern or detection of local atrial fibrillation signals, we may need higher field sensitivity. In addition to field sensitivity, economic aspect of the SQUID system is also important. To simplify the SQUID readout electronics, the output voltage or flux-to-voltage transfer of SQUID should be large enough so that direct measurement of SQUID output can be done using room-temperature preamplifiers. Double relaxation oscillation SQUID (DROS), having about 10 times larger flux-to-voltage transfers than those of DC-SQUIDs, was shown to be a good choice to make the electronics compact. For effective cancellation of external noise inside a thin economic shielded room, first-order axial gradiometer with high balance, simple structure and long-baseline is needed. We developed a technology to make the axial gradiometer compact using direct bonding of superconductive wires between pickup coil and input coil. Conventional insert has mechanical support to hold the gradiometer array, and the dewar neck has equal diameter with the dewar bottom. Boiling of the liquid He can generate mechanical vibrations in the gradiometer array due to mechanical connection structure. Elimination of the mechanical support, and direct mounting of the gradiometer array into the dewar bottom can reduce the dewar neck diameter, resulting in the reduction of liquid He consumption.

  20. SQUIDs for the readout of metallic magnetic calorimeters

    Energy Technology Data Exchange (ETDEWEB)

    Ferring, Anna; Wegner, Mathias; Fleischmann, Andreas; Gastaldo, Loredana; Kempf, Sebastian; Enss, Christian [Kirchhoff-Institute for Physics, Heidelberg University (Germany)

    2015-07-01

    Superconducting quantum interference devices (SQUIDs) are the devices of choice to read out metallic magnetic calorimeters (MMCs). Here, the temperature change of the detector upon the absorption of an energetic particle is measured as a magnetization change of a paramagnetic temperature sensor that is situated in a weak magnetic field. Driven by the need for devices that allow for the readout of large-scale detector arrays with hundreds or even thousands of individual detectors as well as of single channel detectors with sub-eV energy resolution, we have recently started the development of low-T{sub c} current-sensing SQUIDs. In particular, we are developing cryogenic frequency-domain multiplexers based on non-hysteretic rf-SQUIDs for detector array readout as well as dc-SQUIDs for single channel detector readout. We discuss our SQUID designs and the performance of prototype SQUIDs. We particularly focus on the frequency and temperature dependence of the SQUID noise as well as the reliability of our SQUID fabrication process for Nb/Al-AlO{sub x}/Nb Josephson junctions. Additionally, we demonstrate experimentally that state-of-the-art MMCs can successfully be read out with our current devices. Finally, we discuss different strategies to improve the SQUID and detector performance aiming to reach sub-eV energy resolution for individual detectors as well as for detector arrays.

  1. LISA and asteroids

    International Nuclear Information System (INIS)

    Vinet, Jean-Yves

    2006-01-01

    LISA is a joint ESA-NASA mission aiming for cosmic gravitational wave detection and analysis. We address here the question of a special kind of signal caused by asteroid encounters. We present a short theory of the detection of such signals

  2. LISA and the LTP

    International Nuclear Information System (INIS)

    Jennrich, O.

    2002-01-01

    The primary objective of the LISA (Laser Interferometer Space Antenna mission is the detection and observation of gravitational waves from massive black holes (MBH) and galactic binaries in the frequency range 10 -4 Hz ... 10 -1 Hz. This low-frequency range is inaccessible to ground-based interferometers due to the background of local gravitational noise and because ground-based interferometers are limited in length to a few kilometres. LISA is envisaged as an ESA/NASA collaborative project, selected an ESA cornerstone mission and included in NASA's strategic plan and with a nominal launch date in 2011. SMART-2 is primarily intended to demonstrate the key technologies for the ESA/NASA collaborative LISA cornerstone mission. The synergy with the technology being used for Darwin motivates the utilization of SMART-2 for both missions. To this end, SMART-2 will accommodate a LISA technology package (LTP), provided by European institutes and industry and possibly also a Disturbance Reduction System (DRS) that is very similar to the LTP and has the same goals but is provided by US institutes and industry

  3. Low noise SQUIDs

    Science.gov (United States)

    de Waal, V. J.

    1983-02-01

    The present investigation deals with the design, fabrication, and limitations of very sensitive SQUID (Superconducting Quantum Interference Device) magnetometers. The SQUID magnetometer is based on a utilization of the Josephson effect. A description of the theoretical background is provided, and high performance DC SQUIDs with submicron niobium Josephson junctions are discussed, taking into account design considerations, fabrication, junction characterization, the performance of the SQUID and input coil, and the gradiometer performance. The simulation and optimization of a DC SQUID with finite capacitance is considered, giving attention to the implementation of a simulation procedure on a hybrid computer.

  4. Low noise SQUIDs

    Energy Technology Data Exchange (ETDEWEB)

    De Waal, V.J.

    1983-01-01

    The present investigation deals with the design, fabrication, and limitations of very sensitive SQUID (Superconducting Quantum Interference Device) magnetometers. The SQUID magnetometer is based on a utilization of the Josephson effect. A description of the theoretical background is provided, and high performance DC SQUIDs with submicron niobium Josephson junctions are discussed, taking into account design considerations, fabrication, junction characterization, the performance of the SQUID and input coil, and the gradiometer performance. The simulation and optimization of a DC SQUID with finite capacitance is considered, giving attention to the implementation of a simulation procedure on a hybrid computer. 129 references.

  5. Low noise SQUIDS

    International Nuclear Information System (INIS)

    Waal, V.J. de.

    1983-01-01

    The design, fabrication and limitations of very sensitive SQUID magnetometers are described. The SQUID magnetometer is based on the Josephson effect. A very low-noise niobium SQUID is described. It is fabricated with ultra-small niobium junctions with an overlapping area smaller than 1 μm 2 . The photolithographic technique developed for its fabrication, is described. Also an integrated system with a SQUID and a first-order gradiometer on a single substrate is presented. Calculations of the resolution of a dc SQUID containing ideal Josephson junctions according to the RSJ model are presented including a parasitic capacitance. The usefulness of the fabricated SQUIDS as well as some remarks on their performance is considered. (Auth.)

  6. SQUID in NDT

    International Nuclear Information System (INIS)

    Rashdi Shah Ahmad

    2001-01-01

    Superconducting Quantum Interference Device (SQUID) is the most sensitive magnetic flux sensor. It has been used to map the magnetic field on the scalp of human being generated by the brain activity. Currently, a number of groups have tried using SQUID for some special NDT application. This paper reviews some of these work. (Author)

  7. The SQUID Handbook

    CERN Document Server

    Braginski, Alex I

    2006-01-01

    This two-volume handbook offers a comprehensive and well coordinated presentation of SQUIDs (Superconducting Quantum Interference Devices), including device fundamentals, design, technology, system construction and multiple applications. It is intended to bridge the gap between fundamentals and applications, and will be a valuable textbook reference for graduate students and for professionals engaged in SQUID research and engineering. It will also be of use to specialists in multiple fields of practical SQUID applications, from human brain research and heart diagnostics to airplane and nuclear

  8. Market Squid Ecology Dataset

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains ecological information collected on the major adult spawning and juvenile habitats of market squid off California and the US Pacific Northwest....

  9. Market Squid Population Dynamics

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains population dynamics data on paralarvae, juvenile and adult market squid collected off California and the US Pacific Northwest. These data were...

  10. Vortex electronis and squids

    CERN Document Server

    2003-01-01

    Understanding the nature of vortices in high-Tc superconductors is a crucial subject for research on superconductive electronics, especially for superconducting interference devices (SQUIDs), it is also a fundamental problem in condensed-matter physics. Recent technological progress in methods for both direct and indirect observation of vortices, e.g. scanning SQUID, terahertz imaging, and microwave excitation, has led to new insights into vortex physics, the dynamic behavior of vortices in junctions and related questions of noise. This book presents the current status of research activity and provides new information on the applications of SQUIDs, including magnetocardiography, immunoassays, and laser-SQUID microscopes, all of which are close to being commercially available.

  11. Programme [11. international LISA symposium, Zurich (Switzerland), 5-9 September 2016

    International Nuclear Information System (INIS)

    2017-01-01

    analyzing black hole mergers with LISA A. Klein Supermassive Black Hole Observations with eLISA S. Hughes Measuring EMRIs: A reality check Chair: Ch. Caprini L. Mayer Massive black hole mergers and their timescales: connecting galaxy formation with gravitational wave science S. Babak Enchilada: analysis of simulated eLISA data set A. Ricciardone Primordial Gravitational Waves and eLISA S. Sanidas Can eLISA save the day? Hunting for cosmic strings in the SKA era. G. Servant Probing cosmological phase transitions with eLISA D. Weir Acoustic waves and the detectability of first-order phase transitions by eLISA M. Bonetti Post-Newtonian Dynamics of Massive Black Holes Triplets J. Garcia-Bellido Gravitational waves from primordial black holes as dark matter T. Regimbau Searching for the stochastic gravitational-wave background with Advanced LIGO and Advanced Virgo M. Pieroni Primordial GW from universality classes of pseudo-scalar inflation Friday, 9th of September 2016 Chair: G. Mueller K. Holley-Bockelmann The Known Unknowns: predicting the landscape of LISA black hole sources E. Rossi Supermassive black hole seeds: updates on the quasi star model C. Mingarelli The Gravitational-Wave Universe seen by Pulsar Timing Arrays S. Smartt Searching for the electromagnetic counterparts to gravitational wave sources J. Bergé MICROSCOPE: the first few months in orbit O. Jennrich The preparation for L3 – building on LISA Pathfinder (paper)

  12. SQUID application research in Japan

    International Nuclear Information System (INIS)

    Itozaki, Hideo

    2003-01-01

    Japanese research activities using SQUIDs are reviewed in this paper. Low-T c SQUIDs are applied to multi-channel systems for magnetoencephalogram (MEG) and magnetocardiogram (MCG). High-T c SQUIDs are applied to MCG, nondestructive evaluation (NDE), SQUID microscopy, biological testing using fine magnetic markers, geological surveying, food inspection, large-scale integration (LSI) defect analysis and SQUID-NQR (nuclear quadrupole resonance). These applications of SQUIDs are being researched and developed actively and some of them are expected to be in the commercial market in the near future

  13. LISA Pathfinder: A Mission Status

    Science.gov (United States)

    Hewitson, Martin; LISA Pathfinder Team Team

    2016-03-01

    On December 3rd at 04:04 UTC, The European Space Agency launched the LISA Pathfinder satellite on board a VEGA rocket from Kourou in French Guiana. After a series of orbit raising manoeuvres and a 2 month long transfer orbit, LISA Pathfinder arrived at L1. Following a period of commissioning, the science operations commenced at the start of March, beginning the demonstration of technologies and methodologies which pave the way for a future large-scale gravitational wave observatory in space. This talk will present the scientific goals of the mission, discuss the technologies being tested, elucidate the link to a future space-based observatory, such as LISA, and present preliminary results from the in-orbit operations and experiments.

  14. Improving the sensitivity of LISA

    International Nuclear Information System (INIS)

    Nayak, K Rajesh; Pai, A; Dhurandhar, S V; Vinet, J-Y

    2003-01-01

    It has been shown in several recent papers that the six Doppler data streams obtained from a triangular LISA configuration can be combined by appropriately delaying the data streams for cancelling the laser frequency noise. Raw laser noise is several orders of magnitude above the other noises and thus it is essential to bring it down to the level of other noises such as shot, acceleration, etc. A rigorous and systematic formalism using the powerful techniques of computational commutative algebra was developed, which generates in principle all the data combinations cancelling the laser frequency noise. The relevant data combinations form a first module of syzygies. In this paper, we use this formalism to advantage for optimizing the sensitivity of LISA by analysing the noise and signal covariance matrices. The signal covariance matrix is calculated for binaries whose frequency changes at most adiabatically and the signal is averaged over polarizations and directions. We then present the extremal SNR curves for all the data combinations in the module. They correspond to the eigenvectors of the noise and signal covariance matrices. A LISA 'network' SNR is also computed by combining the outputs of the eigenvectors. We show that substantial gains in sensitivity can be obtained by employing these strategies. The maximum SNR curve can yield an improvement up to 70% over the Michelson, mainly at high frequencies, while the improvement using the network SNR ranges from 40% to over 100%. Finally, we describe a simple toy model, in which LISA rotates in a plane. In this analysis, we estimate the improvement in the LISA sensitivity, if one switches from one data combination to another as it rotates. Here the improvement in sensitivity, if one switches optimally over three cyclic data combinations of the eigenvector, is about 55% on average over the LISA bandwidth. The corresponding SNR improvement increases to 60%, if one maximizes over the module

  15. Molecular laser stabilization for LISA

    Science.gov (United States)

    Halloin, Hubert; Acef, Ouali; Argence, Berengere; Jeannin, Olivier; Prat, Pierre; de Vismes, Eden; Plagnol, Eric; Brillet, Alain; Mondin, Linda; Berthon, Jacques; Turazza, Oscar

    2017-11-01

    The expected performance of LISA relies on two main technical challenges: the ability for the spacecrafts to precisely follow the free-flying masses and the outstanding precision of the phase shift measurement. This latter constraint requires frequency stabilized lasers and efficient numerical algorithms to account for the redundant, delayed noise propagation, thus cancelling laser phase noise by many orders of magnitude (TDI methods). Recently involved in the technical developments for LISA, the goal of our team at APC (France) is to contribute on these two subjects: frequency reference for laser stabilization and benchtop simulation of the interferometer. In the present design of LISA, two stages of laser stabilization are used (not accounting for the "post-processed" TDI algorithm): laser pre-stabilization on a frequency reference and lock on the ultra stable distance between spacecrafts (arm-locking). While the foreseen (and deeply studied) laser reference consists of a Fabry-Perot cavity, other techniques may be suitable for LISA or future metrology missions. In particular, locking to a molecular reference (namely iodine in the case of the LISA Nd:YAG laser) is an interesting alternative. It offers the required performance with very good long-term stability (absolute frequency reference) though the reference can be slightly tuned to account for arm-locking. This technique is currently being investigated by our team and optimized for LISA (compactness, vacuum compatibility, ease of use and initialization, etc.). A collaboration with a French laboratory (the SYRTE) had been started aiming to study a second improved technique consisting in inserting the iodine cell in a Fabry-Perot cavity. Ongoing results and prospects to increase the performance of the system are presented in the present article.

  16. The Stationary SQUID

    Science.gov (United States)

    Berger, Jorge

    2018-06-01

    In the customary mode of operation of a SQUID, the electromagnetic field in the SQUID is an oscillatory function of time. In this situation, electromagnetic radiation is emitted and couples to the sample. This is a back action that can alter the state that we intend to measure. A circuit that could perform as a stationary SQUID consists of a loop of superconducting material that encloses the magnetic flux, connected to a superconducting and to a normal electrode. This circuit does not contain Josephson junctions, or any other miniature feature. We study the evolution of the order parameter and of the electrochemical potential in this circuit; they converge to a stationary regime, and the voltage between the electrodes depends on the enclosed flux. We obtain expressions for the power dissipation and for the heat transported by the electric current; the validity of these expressions does not rely on a particular evolution model for the order parameter. We evaluate the influence of fluctuations. For a SQUID perimeter of the order of 1μ m and temperature 0.9T_c, we obtain a flux resolution of the order of 10^{-5}Φ _0/Hz^{1/2}; the resolution is expected to improve as the temperature is lowered.

  17. Characterisation of micro and nano SQUIDs at variable temperature and magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Koehn, Claudia; Storm, Jan-Hendrik; Bechstein, Sylke; Schurig, Thomas [Physikalisch-Technische Bundesanstalt, Abbestrasse 2-12, 10587 Berlin (Germany)

    2015-07-01

    SQUIDs are highly suited to investigate the magnetic properties of samples with small dimensions, such as nanoparticles, or to read out nanoelectromechanical systems (NEMS). Due to the small sample size, SQUIDs with dimensions in the μm or nm regime are desirable. These micro or nano SQUIDs should have a low noise and no hysteresis in the current-voltage-characteristic, even when operated in high magnetic fields of up to several 100 mT. To investigate such SQUID, we developed measurement setups which can simulate the measurement conditions of the intended SQUID application. The design and performance of two measurement setups will be shown and compared. One setup uses a dipstick that is immersed in liquid helium and can be evacuated to provide SQUID temperatures between 4.5 K and 10 K. The other one uses an evaporation cryostat so that the temperature can be varied from 2 K to 60 K. Both setups are equipped with coils to enable SQUID operation in variable magnetic field. To minimize noise, the output of the SQUID under test is preamplified by a SQUID series array which is operated at 4.2 K. First results of the characterisation of micro and nano SQUIDs will be presented.

  18. Laser modulator for LISA pathfinder

    Science.gov (United States)

    Voland, C.; Lund, G.; Coppoolse, W.; Crosby, P.; Stadler, M.; Kudielka, K.; Özkan, C.

    2017-11-01

    LISA Pathfinder is an ESA experiment to demonstrate the key technologies needed for the LISA mission to detect gravitational waves in space. The LISA Pathfinder spacecraft represents one arm of the LISA interferometer, containing an optical metrology system and two proof masses as inertial references for the drag-free control system. The LISA Pathfinder payload consists of two drag-free floating test masses located in the inertial sensors with their control electronics and an optical metrology subsystem. The optical metrology subsystem monitors the movement of both test masses relative to each other and to the spacecraft with very high sensitivity and resolution. This is achieved with a heterodyne Mach- Zehnder interferometer. This interferometer requires as input two coherent laser beams with a heterodyne frequency difference of a few kHz. To generate the two laser beams with a heterodyne frequency difference a Nd:YAG laser is used together with the Laser Modulator. The Nd:YAG laser generates a single coherent laser signal at a wavelength of 1064nm which is fibre coupled to the Laser Modulator. The Laser Modulator then generates the two optical beams with the required heterodyne frequency offset. In addition, the Laser Modulator is required to perform laser amplitude stabilization and optical path difference control for the two optical signals. The Laser Modulator consists of an optical unit - the LMU - and RF synthesiser, power amplification and control electronics. These electronics are all housed in the Laser Modulator Electronics (LME). The LMU has four primary functions: • Splitting of the input laser beam into two paths for later superposition in the interferometer. • Applying different frequency shifts to each of the beams. • Providing amplitude modulation control to each of the beams. • Providing active control of the optical path length difference between the two optical paths. The present paper describes the design and performance of the LMU

  19. Lisa Jevbratt / Lisa Jevbratt ; interv. Tilman Baumgärtel

    Index Scriptorium Estoniae

    Jevbratt, Lisa

    2006-01-01

    1967. a. Rootsis sündinud ja USA-s elavast kunstnikust Lisa Jevbrattist ning tema loomingust, 2000. a. jaanuaris tehtud meiliintervjuu kunstnikuga. L. Jevbratt kuulub rühmitusse C5, tema teosed keskenduvad pigem Interneti struktuurile kui selle sisule. Pikemalt võrguteosest "1:1" (2000), mille teemaks on IP-aadressid., lühidalt tööst "The Stillman Project" (1997), kunstniku galeriist "Non-Site"

  20. Cryostats for SQUID magnetometers

    International Nuclear Information System (INIS)

    Testard, O.A.; Locatelli, M.

    1982-05-01

    A non metallic and non magnetic cryostat, with a very low thermal budget and a container type autonomy was developed, to condition S.Q.U.I.D. magnetometers which maximum sensitivity reaches 10 -14 Tesla Hertzsup(-1/2). This instrumentation puts in hand new concepts of composite materials, thermal shock and vibration resistant, multilayer thermal radiative insulation also to the prouve of vibrations with thermal equivalent emissivity lower than 10 -3

  1. Recent advancements in the SQUID magnetospinogram system

    Science.gov (United States)

    Adachi, Yoshiaki; Kawai, Jun; Haruta, Yasuhiro; Miyamoto, Masakazu; Kawabata, Shigenori; Sekihara, Kensuke; Uehara, Gen

    2017-06-01

    In this study, a new superconducting quantum interference device (SQUID) biomagnetic measurement system known as magnetospinogram (MSG) is developed. The MSG system is used for observation of a weak magnetic field distribution induced by the neural activity of the spinal cord over the body surface. The current source reconstruction for the observed magnetic field distribution provides noninvasive functional imaging of the spinal cord, which enables medical personnel to diagnose spinal cord diseases more accurately. The MSG system is equipped with a uniquely shaped cryostat and a sensor array of vector-type SQUID gradiometers that are designed to detect the magnetic field from deep sources across a narrow observation area over the body surface of supine subjects. The latest prototype of the MSG system is already applied in clinical studies to develop a diagnosis protocol for spinal cord diseases. Advancements in hardware and software for MSG signal processing and cryogenic components aid in effectively suppressing external magnetic field noise and reducing the cost of liquid helium that act as barriers with respect to the introduction of the MSG system to hospitals. The application of the MSG system is extended to various biomagnetic applications in addition to spinal cord functional imaging given the advantages of the MSG system for investigating deep sources. The study also includes a report on the recent advancements of the SQUID MSG system including its peripheral technologies and wide-spread applications.

  2. Micrometeorite Science with LISA Pathfinder

    Science.gov (United States)

    Pagane, Nicole; Thorpe, James Ira; Littenberg, Tyson; Littenberg, Tyson; Baker, John; Slutsky, Jacob; Hourihane, Sophie; LISA Pathfinder Team

    2018-01-01

    The primary objective of LISA Pathfinder (LPF) was to demonstrate drag-free control of test masses—along with the technology necessary to maintain the inertial motion—that LISA (Laser Interferometer Space Antenna) would later utilize as a space-based gravitational wave observatory. Due to the precise interferometry used during the mission, LPF could be employed as an accelerometer and used to detect micrometeorite impacts while in orbit about the Sun-Earth Lagrange Point L1. To infer micrometeorite impacts, the flight data was processed for event reconstruction to determine external acceleration of LPF; impact parameters were then estimated through a Markov-Chain Monte-Carlo (MCMC) tool via Bayesian analysis by fitting delta functions in the acceleration domain. As impact candidates were collected, a catalog of event data was curated with the reconstructed estimated parameters, among which were impact sky localizations that were later rotated into more intuitive reference frames. To infer the results of this dust modeling technique, current micrometeorite models were compared to the impact data. In the final reference frame common to the available micrometeorite models, the reconstructed impacts appear to cluster at (±90°, 0°)—where impacts prograde in this longitude-latitude frame were at (-90°, 0°), retrograde were (90°, 0°), and the sun was centered at the origin. The two available models used for comparison were of the Jupiter-family comets (JFC) and Halley-type comets (HTC), which clustered primarily around (±90°, 0°) and (0°, ±20°) respectively. This suggests that the JFC population seems to account for the majority of the impacts detected by LPF. The models’ expected rates given localization and velocity are currently being compared to the reconstructed data to further characterize the micrometeorite populations at L1. We will present our current analysis of this data set and discuss possibilities of extending such an analysis for LISA.

  3. LISA Pathfinder: OPD loop characterisation

    Science.gov (United States)

    Born, Michael; LPF Collaboration

    2017-05-01

    The optical metrology system (OMS) of the LISA Pathfinder mission is measuring the distance between two free-floating test masses with unprecedented precision. One of the four OMS heterodyne interferometers reads out the phase difference between the reference and the measurement laser beam. This phase from the reference interferometer is common to all other longitudinal interferometer read outs and therefore subtracted. In addition, the phase is fed back via the digital optical pathlength difference (OPD) control loop to keep it close to zero. Here, we analyse the loop parameters and compare them to on-ground measurement results.

  4. Observing a Gravitational Wave Background With Lisa

    National Research Council Canada - National Science Library

    Tinto, M; Armstrong, J; Estabrook, F

    2000-01-01

    ... formation of several observables. All are independent of lasers and frequency standard phase fluctuations, but have different couplings to gravitational waves and to the various LISA instrumental noises...

  5. Mona Lisa, lesbiahvid ja seksilaulud / Kaivo Kopli

    Index Scriptorium Estoniae

    Kopli, Kaivo

    2003-01-01

    Ameerika Teaduse Edendamise Assotsiatsiooni (AAA) konverentsil esitatud uusimatest teadusuuringutest. Artiklid: Mona Lisa naeratuse saladus paljastatud ; Lesbilised Jaapani makaagid seljatavad Darwini ; Linnud õpivad uusi laule uue partneri leidmiseks

  6. LISA Pathfinder instrument data analysis

    Science.gov (United States)

    Guzman, Felipe

    LISA Pathfinder (LPF) is an ESA-launched demonstration mission of key technologies required for the joint NASA-ESA gravitational wave observatory in space, LISA. As part of the LPF interferometry investigations, analytic models of noise sources and corresponding noise subtrac-tion techniques have been developed to correct for effects like the coupling of test mass jitter into displacement readout, and fluctuations of the laser frequency or optical pathlength difference. Ground testing of pre-flight hardware of the Optical Metrology Subsystem is currently ongoing at the Albert Einstein Institute Hannover. In collaboration with NASA Goddard Space Flight Center, the LPF mission data analysis tool LTPDA is being used to analyze the data product of these tests. Furthermore, the noise subtraction techniques and in-flight experiment runs for noise characterization are being defined as part of the mission experiment master plan. We will present the data analysis outcome of pre-flight hardware ground tests and possible noise subtraction strategies for in-flight instrument operations.

  7. Lisa Woodward | IDRC - International Development Research Centre

    International Development Research Centre (IDRC) Digital Library (Canada)

    Lisa Woodward is Special Advisor to the President. Before joining IDRC, Lisa held positions in strategic planning, performance measurement, evaluation, risk management, and policy development in federal organizations, including Fisheries and Oceans Canada, the Canadian International Development Agency, and the ...

  8. LISA: Probing the Universe with Gravitational Waves

    NARCIS (Netherlands)

    Prince, T.A.; Binetruy, P.; Centrella, J.; Finn, L.S.; Hogan, C.; Nelemans, G.A.; Phinney, E.S.; Schutz, B.; Team, L.I.S.

    2006-01-01

    LISA is a joint NASA/ESA space mission for detection and study of low-frequency gravitational waves in the band from 0.1 mHz to 0.1 Hz. The mission consists of three satellites separated by a nominal distance of 5 million kilometers, with precision metrology provided by laser ranging. LISA will

  9. SQUID technology for geophysical exploration

    International Nuclear Information System (INIS)

    Meyer, Hans-Georg; Stolz, R.; Chwala, A.; Schulz, M.

    2005-01-01

    We report on successful tests of planar LTS SQUID gradiometers on airborne platforms such as helicopter and aircraft. The system works stable and allows profile work without any constraints. In mobile applications the gradient resolution at low frequencies is dominated by motion noise, since the parasitic areas of the SQUID gradiometer lead to strong disturbances if the gradiometer is tilted in the homogenous Earth's magnetic field. The balance can be improved further by software using data of a SQUID magnetometer triple. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  10. Black Holes, Gravitational Waves, and LISA

    Science.gov (United States)

    Baker, John

    2009-01-01

    Binary black hole mergers are central to many key science objectives of the Laser Interferometer Space Antenna (LISA). For many systems the strongest part of the signal is only understood by numerical simulations. Gravitational wave emissions are understood by simulations of vacuum General Relativity (GR). I discuss numerical simulation results from the perspective of LISA's needs, with indications of work that remains to be done. Some exciting scientific opportunities associated with LISA observations would be greatly enhanced if prompt electromagnetic signature could be associated. I discuss simulations to explore this possibility. Numerical simulations are important now for clarifying LISA's science potential and planning the mission. We also consider how numerical simulations might be applied at the time of LISA's operation.

  11. Performance of a novel SQUID-based superconducting imaging-surface magnetoencephalography system

    Science.gov (United States)

    Kraus, R. H.; Volegov, P.; Maharajh, K.; Espy, M. A.; Matlashov, A. N.; Flynn, E. R.

    2002-03-01

    Performance for a recently completed whole-head magnetoencephalography system using a superconducting imaging surface (SIS) surrounding an array of 150 SQUID magnetometers is reported. The helmet-like SIS is hemispherical in shape with a brim. Conceptually, the SIS images nearby sources onto the SQUIDs while shielding sensors from distant “noise” sources. A finite element method (FEM) description using the as-built geometry was developed to describe the SIS effect on source fields by imposing B⊥( surface)=0 . Sensors consist of 8×8 mm 2 SQUID magnetometers with 0.84 nT/ Φ0 sensitivity and positions and orientations was found. Good agreement was found between modeled and measured shielding of the SQUIDs from sources external to the array showing significant frequency-independent shielding. Phantom localization precision was better than 0.5 mm at all locations with a mean of better than 0.3 mm.

  12. Possible LISA Technology Applications for Other Missions

    Science.gov (United States)

    Livas, Jeffrey

    2018-01-01

    The Laser Interferometer Space Antenna (LISA) has been selected as the third large class mission launch opportunity of the Cosmic Visions Program by the European Space Agency (ESA). LISA science will explore a rich spectrum of astrophysical gravitational-wave sources expected at frequencies between 0.0001 and 0.1 Hz and complement the work of other observatories and missions, both space and ground-based, electromagnetic and non-electromagnetic. Similarly, LISA technology may find applications for other missions. This paper will describe the capabilities of some of the key technologies and discuss possible contributions to other missions.

  13. Lisa's Lemonade Stand: Exploring Algebraic Ideas.

    Science.gov (United States)

    Billings, Esther M. H.; Lakatos, Tracy

    2003-01-01

    Presents an activity, "Lisa's Lemonade Stand," that actively engages students in algebraic thinking as they analyze change by investigating relationships between variables and gain experience describing and representing these relationships graphically. (YDS)

  14. Optimizing the Earth-LISA 'rendezvous'

    International Nuclear Information System (INIS)

    De Marchi, Fabrizio; Pucacco, Giuseppe; Bassan, Massimo

    2012-01-01

    We present a general survey of heliocentric LISA orbits, hoping that it might help in the exercise of rescoping the mission. We try to semi-analytically optimize the orbital parameters in order to minimize the disturbances coming from the Earth-LISA interaction. In a set of numerical simulations, we include non-autonomous perturbations and provide an estimate of Doppler shift and breathing as a function of the trailing angle. (paper)

  15. Paleomagnetic Analysis Using SQUID Microscopy

    Science.gov (United States)

    Weiss, Benjamin P.; Lima, Eduardo A.; Fong, Luis E.; Baudenbacher, Franz J.

    2007-01-01

    Superconducting quantum interference device (SQUID) microscopes are a new generation of instruments that map magnetic fields with unprecedented spatial resolution and moment sensitivity. Unlike standard rock magnetometers, SQUID microscopes map magnetic fields rather than measuring magnetic moments such that the sample magnetization pattern must be retrieved from source model fits to the measured field data. In this paper, we presented the first direct comparison between paleomagnetic analyses on natural samples using joint measurements from SQUID microscopy and moment magnetometry. We demonstrated that in combination with apriori geologic and petrographic data, SQUID microscopy can accurately characterize the magnetization of lunar glass spherules and Hawaiian basalt. The bulk moment magnitude and direction of these samples inferred from inversions of SQUID microscopy data match direct measurements on the same samples using moment magnetometry. In addition, these inversions provide unique constraints on the magnetization distribution within the sample. These measurements are among the most sensitive and highest resolution quantitative paleomagnetic studies of natural remanent magnetization to date. We expect that this technique will be able to extend many other standard paleomagnetic techniques to previously inaccessible microscale samples.

  16. Novel Payload Architectures for LISA

    Science.gov (United States)

    Johann, Ulrich A.; Gath, Peter F.; Holota, Wolfgang; Schulte, Hans Reiner; Weise, Dennis

    2006-11-01

    As part of the current LISA Mission Formulation Study, and based on prior internal investigations, Astrium Germany has defined and preliminary assessed novel payload architectures, potentially reducing overall complexity and improving budgets and costs. A promising concept is characterized by a single active inertial sensor attached to a single optical bench and serving both adjacent interferometer arms via two rigidly connected off-axis telescopes. The in-plane triangular constellation ``breathing angle'' compensation is accomplished by common telescope in-field of view pointing actuation of the transmit/received beams line of sight. A dedicated actuation mechanism located on the optical bench is required in addition to the on bench actuators for differential pointing of the transmit and receive direction perpendicular to the constellation plane. Both actuators operate in a sinusoidal yearly period. A technical challenge is the actuation mechanism pointing jitter and the monitoring and calibration of the laser phase walk which occurs while changing the optical path inside the optical assembly during re-pointing. Calibration or monitoring of instrument internal phase effects e.g. by a laser metrology truss derived from the existing interferometry is required. The architecture exploits in full the two-step interferometry (strap down) concept, separating functionally inter spacecraft and intra-spacecraft interferometry (reference mass laser metrology degrees of freedom sensing). The single test mass is maintained as cubic, but in free-fall in the lateral degrees of freedom within the constellation plane. Also the option of a completely free spherical test mass with full laser interferometer readout has been conceptually investigated. The spherical test mass would rotate slowly, and would be allowed to tumble. Imperfections in roundness and density would be calibrated from differential wave front sensing in a tetrahedral arrangement, supported by added attitude

  17. Tracking Electromagnetic Energy With SQUIDs

    Science.gov (United States)

    2005-01-01

    A superconducting quantum interference device (SQUID) is a gadget used to measure extremely weak signals, specifically magnetic flux. It can detect subtle changes in energy, up to 100 billion times weaker than the electromagnetic energy required to move a compass needle. SQUIDs are used for a variety of testing procedures where extreme sensitivity is required and where the test instrument need not come into direct contact with the test subject. NASA uses SQUIDs for remote, noncontact sensing in a variety of venues, including monitoring the Earth s magnetic field and tracking brain activity of pilots. Scientists at NASA s Goddard Space Flight Center have been making extensive use of this technology, from astrophysical research, to tracking the navigational paths of bees in flight to determine if they are using internal compasses. These very sensitive measurement devices have a wide variety of uses within NASA and even more uses within the commercial realm.

  18. Confusion noise from LISA capture sources

    International Nuclear Information System (INIS)

    Barack, Leor; Cutler, Curt

    2004-01-01

    Captures of compact objects (COs) by massive black holes (MBHs) in galactic nuclei will be an important source for LISA, the proposed space-based gravitational wave (GW) detector. However, a large fraction of captures will not be individually resolvable - either because they are too distant, have unfavorable orientation, or have too many years to go before final plunge - and so will constitute a source of 'confusion noise', obscuring other types of sources. In this paper we estimate the shape and overall magnitude of the GW background energy spectrum generated by CO captures. This energy spectrum immediately translates to a spectral density S h capt (f) for the amplitude of capture-generated GWs registered by LISA. The overall magnitude of S h capt (f) is linear in the CO capture rates, which are rather uncertain; therefore we present results for a plausible range of rates. S h capt (f) includes the contributions from both resolvable and unresolvable captures, and thus represents an upper limit on the confusion noise level. We then estimate what fraction of S h capt (f) is due to unresolvable sources and hence constitutes confusion noise. We find that almost all of the contribution to S h capt (f) coming from white dwarf and neutron star captures, and at least ∼30% of the contribution from black hole captures, is from sources that cannot be individually resolved. Nevertheless, we show that the impact of capture confusion noise on the total LISA noise curve ranges from insignificant to modest, depending on the rates. Capture rates at the high end of estimated ranges would raise LISA's overall (effective) noise level [fS h eff (f)] 1/2 by at most a factor ∼2 in the frequency range 1-10 mHz, where LISA is most sensitive. While this slightly elevated noise level would somewhat decrease LISA's sensitivity to other classes of sources, we argue that, overall, this would be a pleasant problem for LISA to have: It would also imply that detection rates for CO captures

  19. Free-flight experiments in LISA Pathfinder

    International Nuclear Information System (INIS)

    Armano, M; Audley, H; Born, M; Danzmann, K; Diepholz, I; Auger, G; Binetruy, P; Baird, J; Bortoluzzi, D; Brandt, N; Bursi, A; Caleno, M; Cavalleri, A; Cesarini, A; Dolesi, R; Ferroni, V; Cruise, M; Cutler, C; Dunbar, N; Ferraioli, L

    2015-01-01

    The LISA Pathfinder mission will demonstrate the technology of drag-free test masses for use as inertial references in future space-based gravitational wave detectors. To accomplish this, the Pathfinder spacecraft will perform drag-free flight about a test mass while measuring the acceleration of this primary test mass relative to a second reference test mass. Because the reference test mass is contained within the same spacecraft, it is necessary to apply forces on it to maintain its position and attitude relative to the spacecraft. These forces are a potential source of acceleration noise in the LISA Pathfinder system that are not present in the full LISA configuration. While LISA Pathfinder has been designed to meet it's primary mission requirements in the presence of this noise, recent estimates suggest that the on-orbit performance may be limited by this ‘suspension noise’. The drift-mode or free-flight experiments provide an opportunity to mitigate this noise source and further characterize the underlying disturbances that are of interest to the designers of LISA-like instruments. This article provides a high-level overview of these experiments and the methods under development to analyze the resulting data. (paper)

  20. SQUID-based measuring systems

    Indian Academy of Sciences (India)

    field produced by a given two-dimensional current density distribution is inverted using the Fourier transform technique. Keywords ... Superconducting quantum interference devices (SQUIDs) are the most sensitive detectors for measurement of ... omagnetic prospecting, detection of gravity waves etc. Judging the importance ...

  1. Compact integrated dc SQUID gradiometer

    Science.gov (United States)

    de Waal, V. J.; Klapwijk, T. M.

    1982-10-01

    An all-niobium integrated system of first-order gradiometer and dc suprconducting quantum interference device (SQUID) has been developed. It is relatively simple to fabricate, has an overall size of 17×12 mm and a sensitivity of 3.5×10-12 T m-1 Hz-1/2.

  2. Compact integrated dc SQUID gradiometer

    Energy Technology Data Exchange (ETDEWEB)

    de Waal, V.J.; Klapwijk, T.M.

    1982-10-01

    An all-niobium integrated system of first-order gradiometer and dc suprconducting quantum interference device (SQUID) has been developed. It is relatively simple to fabricate, has an overall size of 17 x 12 mm and a sensitivity of 3.5 x 10/sup -12/ T m/sup -1/ Hz/sup -1/2/.

  3. Squids: applications outside the laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Falco, C M

    1978-07-01

    Originally thought to be rather esoteric, SQUIDS (superconducting quantum interference devices) have moved from the realms of theory to practical application since 1962. The promise for the not-too-distant future is a superconducting computer, with 10/sup 5/ logic elements in a 1cm cube.

  4. STM-SQUID probe microscope

    International Nuclear Information System (INIS)

    Hayashi, Tadayuki; Tachiki, Minoru; Itozaki, Hideo

    2007-01-01

    We have developed a STM-SQUID probe microscope. A high T C SQUID probe microscope was combined with a scanning tunneling microscope for investigation of samples at room temperature in air. A high permeability probe needle was used as a magnetic flux guide to improve the spatial resolution. The probe with tip radius of less than 100 nm was prepared by microelectropolishing. The probe was also used as a scanning tunneling microscope tip. Topography of the sample surface could be measured by the scanning tunneling microscope with high spatial resolution prior to observation by SQUID microscopy. The SQUID probe microscope image could be observed while keeping the distance from the sample surface to the probe tip constant. We observed a topographic image and a magnetic image of Ni fine pattern and also a magnetically recorded hard disk. Furthermore we have investigated a sample vibration method of the static magnetic field emanating from a sample with the aim of achieving a higher signal-to-noise (S/N) ratio

  5. Cold SQUIDs and hot samples

    Energy Technology Data Exchange (ETDEWEB)

    Lee, T.S.C. [Univ. of California, Berkeley, CA (United States). Dept. of Physics]|[Lawrence Berkeley national Lab., CA (United States). Materials Sciences Div.

    1997-05-01

    Low transition temperature (low-{Tc}) and high-{Tc} Superconducting QUantum Interference Devices (SQUIDs) have been used to perform high-resolution magnetic measurements on samples whose temperatures are much higher than the operating temperatures of the devices. Part 1 of this work focuses on measurements of the rigidity of flux vortices in high-{Tc} superconductors using two low-{Tc} SQUIDs, one on either side of a thermally-insulated sample. The correlation between the signals of the SQUIDs is a direct measure of the extent of correlation between the movements of opposite ends of vortices. These measurements were conducted under the previously-unexplored experimental conditions of nominally-zero applied magnetic field, such that vortex-vortex interactions were unimportant, and with zero external current. At specific temperatures, the authors observed highly-correlated noise sources, suggesting that the vortices moved as rigid rods. At other temperatures, the noise was mostly uncorrelated, suggesting that the relevant vortices were pinned at more than one point along their length. Part 2 describes the design, construction, performance, and applications of a scanning high-{Tc} SQUID microscope optimized for imaging room-temperature objects with very high spatial resolution and magnetic source sensitivity.

  6. How the SQUID was born

    International Nuclear Information System (INIS)

    Silver, Arnold H

    2006-01-01

    I was asked to speak about the discovery and invention of the SQUID at the International Superconducting Electronics Conference (ISEC) 2005 banquet. This narrative is based on my personal recollections of the sequence of events and the motivations. I have edited the text and added figures for clarity. Although it is an old story, it may contain some useful lessons

  7. Properties of high temperature SQUIDS

    International Nuclear Information System (INIS)

    Falco, C.M.; Wu, C.T.

    1978-01-01

    A review is given of the present status of weak links and dc and rf biased SQUIDs made with high temperature superconductors. A method for producing reliable, reproducible devices using Nb 3 Sn is outlined, and comments are made on directions future work should take

  8. Cold SQUIDs and hot samples

    International Nuclear Information System (INIS)

    Lee, T.S.C.; Lawrence Berkeley national Lab., CA

    1997-05-01

    Low transition temperature (low-T c ) and high-T c Superconducting QUantum Interference Devices (SQUIDs) have been used to perform high-resolution magnetic measurements on samples whose temperatures are much higher than the operating temperatures of the devices. Part 1 of this work focuses on measurements of the rigidity of flux vortices in high-T c superconductors using two low-T c SQUIDs, one on either side of a thermally-insulated sample. The correlation between the signals of the SQUIDs is a direct measure of the extent of correlation between the movements of opposite ends of vortices. These measurements were conducted under the previously-unexplored experimental conditions of nominally-zero applied magnetic field, such that vortex-vortex interactions were unimportant, and with zero external current. At specific temperatures, the authors observed highly-correlated noise sources, suggesting that the vortices moved as rigid rods. At other temperatures, the noise was mostly uncorrelated, suggesting that the relevant vortices were pinned at more than one point along their length. Part 2 describes the design, construction, performance, and applications of a scanning high-T c SQUID microscope optimized for imaging room-temperature objects with very high spatial resolution and magnetic source sensitivity

  9. How the SQUID was born

    Energy Technology Data Exchange (ETDEWEB)

    Silver, Arnold H [Northrop Grumman Space Technology, One Space Park, Redondo Beach, CA 90278 (United States)

    2006-05-15

    I was asked to speak about the discovery and invention of the SQUID at the International Superconducting Electronics Conference (ISEC) 2005 banquet. This narrative is based on my personal recollections of the sequence of events and the motivations. I have edited the text and added figures for clarity. Although it is an old story, it may contain some useful lessons.

  10. Data analysis for the LISA Technology Package

    International Nuclear Information System (INIS)

    Hewitson, M; Danzmann, K; Diepholz, I; GarcIa, A; Armano, M; Fauste, J; Benedetti, M; Bogenstahl, J; Bortoluzzi, D; Bosetti, P; Cristofolini, I; Brandt, N; Cavalleri, A; Ciani, G; Dolesi, R; Ferraioli, L; Cruise, M; Fertin, D; GarcIa, C; Fichter, W

    2009-01-01

    The LISA Technology Package (LTP) on board the LISA Pathfinder mission aims to demonstrate some key concepts for LISA which cannot be tested on ground. The mission consists of a series of preplanned experimental runs. The data analysis for each experiment must be designed in advance of the mission. During the mission, the analysis must be carried out promptly so that the results can be fed forward into subsequent experiments. As such a robust and flexible data analysis environment needs to be put in place. Since this software is used during mission operations and effects the mission timeline, it must be very robust and tested to a high degree. This paper presents the requirements, design and implementation of the data analysis environment (LTPDA) that will be used for analysing the data from LTP. The use of the analysis software to perform mock data challenges (MDC) is also discussed, and some highlights from the first MDC are presented.

  11. Data analysis for the LISA Technology Package

    Energy Technology Data Exchange (ETDEWEB)

    Hewitson, M; Danzmann, K; Diepholz, I; GarcIa, A [Albert-Einstein-Institut, Max-Planck-Institut fuer Gravitationsphysik und Universitaet Hannover, 30167 Hannover (Germany); Armano, M; Fauste, J [European Space Agency, ESAC, Villanueva de la Canada, 28692 Madrid (Spain); Benedetti, M [Dipartimento di Ingegneria dei Materiali e Tecnologie Industriali, Universita di Trento and INFN, Gruppo Collegato di Trento, Mesiano, Trento (Italy); Bogenstahl, J [Department of Physics and Astronomy, University of Glasgow, Glasgow (United Kingdom); Bortoluzzi, D; Bosetti, P; Cristofolini, I [Dipartimento di Ingegneria Meccanica e Strutturale, Universita di Trento and INFN, Gruppo Collegato di Trento, Mesiano, Trento (Italy); Brandt, N [Astrium GmbH, 88039 Friedrichshafen (Germany); Cavalleri, A; Ciani, G; Dolesi, R; Ferraioli, L [Dipartimento di Fisica, Universita di Trento and INFN, Gruppo Collegato di Trento, 38050 Povo, Trento (Italy); Cruise, M [Department of Physics and Astronomy, University of Birmingham, Birmingham (United Kingdom); Fertin, D; GarcIa, C [European Space Agency, ESTEC, 2200 AG Noordwijk (Netherlands); Fichter, W, E-mail: martin.hewitson@aei.mpg.d [Institut fuer Flugmechanik und Flugregelung, 70569 Stuttgart (Germany)

    2009-05-07

    The LISA Technology Package (LTP) on board the LISA Pathfinder mission aims to demonstrate some key concepts for LISA which cannot be tested on ground. The mission consists of a series of preplanned experimental runs. The data analysis for each experiment must be designed in advance of the mission. During the mission, the analysis must be carried out promptly so that the results can be fed forward into subsequent experiments. As such a robust and flexible data analysis environment needs to be put in place. Since this software is used during mission operations and effects the mission timeline, it must be very robust and tested to a high degree. This paper presents the requirements, design and implementation of the data analysis environment (LTPDA) that will be used for analysing the data from LTP. The use of the analysis software to perform mock data challenges (MDC) is also discussed, and some highlights from the first MDC are presented.

  12. Reconstructing the dark sector interaction with LISA

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Rong-Gen; Yang, Tao [CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, P.O. Box 2735, Beijing 100190 (China); Tamanini, Nicola, E-mail: cairg@itp.ac.cn, E-mail: nicola.tamanini@cea.fr, E-mail: yangtao@itp.ac.cn [Institut de Physique Théorique, CEA-Saclay, CNRS UMR 3681, Université Paris-Saclay, F-91191 Gif-sur-Yvette (France)

    2017-05-01

    We perform a forecast analysis of the ability of the LISA space-based interferometer to reconstruct the dark sector interaction using gravitational wave standard sirens at high redshift. We employ Gaussian process methods to reconstruct the distance-redshift relation in a model independent way. We adopt simulated catalogues of standard sirens given by merging massive black hole binaries visible by LISA, with an electromagnetic counterpart detectable by future telescopes. The catalogues are based on three different astrophysical scenarios for the evolution of massive black hole mergers based on the semi-analytic model of E. Barausse, Mon. Not. Roy. Astron. Soc. 423 (2012) 2533. We first use these standard siren datasets to assess the potential of LISA in reconstructing a possible interaction between vacuum dark energy and dark matter. Then we combine the LISA cosmological data with supernovae data simulated for the Dark Energy Survey. We consider two scenarios distinguished by the time duration of the LISA mission: 5 and 10 years. Using only LISA standard siren data, the dark sector interaction can be well reconstructed from redshift z ∼1 to z ∼3 (for a 5 years mission) and z ∼1 up to z ∼5 (for a 10 years mission), though the reconstruction is inefficient at lower redshift. When combined with the DES datasets, the interaction is well reconstructed in the whole redshift region from 0 z ∼ to z ∼3 (5 yr) and z ∼0 to z ∼5 (10 yr), respectively. Massive black hole binary standard sirens can thus be used to constrain the dark sector interaction at redshift ranges not reachable by usual supernovae datasets which probe only the z ∼< 1.5 range. Gravitational wave standard sirens will not only constitute a complementary and alternative way, with respect to familiar electromagnetic observations, to probe the cosmic expansion, but will also provide new tests to constrain possible deviations from the standard ΛCDM dynamics, especially at high redshift.

  13. LISA Mission and System architectures and performances

    International Nuclear Information System (INIS)

    Gath, Peter F; Weise, Dennis; Schulte, Hans-Reiner; Johann, Ulrich

    2009-01-01

    In the context of the LISA Mission Formulation Study, the LISA System was studied in detail and a new baseline architecture for the whole mission was established. This new baseline is the result of trade-offs on both, mission and system level. The paper gives an overview of the different mission scenarios and configurations that were studied in connection with their corresponding advantages and disadvantages as well as performance estimates. Differences in the required technologies and their influence on the overall performance budgets are highlighted for all configurations. For the selected baseline concept, a more detailed description of the configuration is given and open issues in the technologies involved are discussed.

  14. LISA Mission and System architectures and performances

    Energy Technology Data Exchange (ETDEWEB)

    Gath, Peter F; Weise, Dennis; Schulte, Hans-Reiner; Johann, Ulrich, E-mail: peter.gath@astrium.eads.ne [Astrium GmbH Satellites, 88039 Friedrichshafen (Germany)

    2009-03-01

    In the context of the LISA Mission Formulation Study, the LISA System was studied in detail and a new baseline architecture for the whole mission was established. This new baseline is the result of trade-offs on both, mission and system level. The paper gives an overview of the different mission scenarios and configurations that were studied in connection with their corresponding advantages and disadvantages as well as performance estimates. Differences in the required technologies and their influence on the overall performance budgets are highlighted for all configurations. For the selected baseline concept, a more detailed description of the configuration is given and open issues in the technologies involved are discussed.

  15. Galactic binaries with eLISA

    OpenAIRE

    Nelemans, G.

    2013-01-01

    I review what eLISA will see from Galactic binaries -- double stars with orbital periods less than a few hours and white dwarf (or neutron star/black hole) components. I discuss the currently known binaries that are guaranteed (or verification) sources and explain why the expected total number of eLISA Galactic binaries is several thousand, even though there are large uncertainties in our knowledge of this population, in particular that of the interacting AM CVn systems. I very briefly sketch...

  16. Towards an improved magnetic diagnostic system for LISA

    International Nuclear Information System (INIS)

    Mateos, I; Lobo, A; Sanjuan, J; Ramos-Castro, J; Nofrarias, M

    2009-01-01

    The current design, and material implementation of the magnetic field sensing in the LISA Technology Package (LTP) on board LISA Pathfinder (LPF), is based on a set of 4 high-precision 3-axis fluxgate magnetometers. In order to avoid magnetic disturbances on the LTP proof masses (TM 's), originated by the sensors themselves, these are placed somewhat far from the TM's, which results in partial field information losses. We are currently investigating alternative magnetic sensing techniques, based on AMR (Anisotropic Magnetoresistive) devices. These are much smaller in size than fluxgates, therefore a more numerous array can be thought of for flight. In addition, there is a chance that they may be attached closer to the TM's, thereby enhancing magnetic field sensing spacial resolution. Several issues need to be addressed, such as real sensitivity (including electronics noise) and set/reset trigger procedures. A brief overview about the stability of the magnetic fields and gradients generated in the LTP by means of the coil will also be given. This paper show the latest results of our research.

  17. Mona Lisa kuulsa naeratuse saladus leidis lahenduse / Johannes Saar

    Index Scriptorium Estoniae

    Saar, Johannes, 1965-

    2004-01-01

    Firenze kunstiajalooõpetaja Giuseppe Pallanti jõudis 25-aastase arhiivitöö tulemusena järeldusele, et Leonardo da Vinci Mona Lisa modelliks on siidikaupmehe Francesco del Giocondo abikaasa Lisa Gerardini

  18. The Mona Lisa of modern science.

    Science.gov (United States)

    Kemp, Martin

    2003-01-23

    No molecule in the history of science has reached the iconic status of the double helix of DNA. Its image has been imprinted on all aspects of society, from science, art, music, cinema, architecture and advertising. This review of the Mona Lisa of science examines the evolution of its form at the hands of both science and art.

  19. NanoSQUIDs: Basics & recent advances

    Science.gov (United States)

    José Martínez-Pérez, Maria; Koelle, Dieter

    2017-08-01

    Superconducting Quantum Interference Devices (SQUIDs) are one of the most popular devices in superconducting electronics. They combine the Josephson effect with the quantization of magnetic flux in superconductors. This gives rise to one of the most beautiful manifestations of macroscopic quantum coherence in the solid state. In addition, SQUIDs are extremely sensitive sensors allowing us to transduce magnetic flux into measurable electric signals. As a consequence, any physical observable that can be converted into magnetic flux, e.g., current, magnetization, magnetic field or position, becomes easily accessible to SQUID sensors. In the late 1980s it became clear that downsizing the dimensions of SQUIDs to the nanometric scale would encompass an enormous increase of their sensitivity to localized tiny magnetic signals. Indeed, nanoSQUIDs opened the way to the investigation of, e.g., individual magnetic nanoparticles or surface magnetic states with unprecedented sensitivities. The purpose of this chapter is to present a detailed survey of microscopic and nanoscopic SQUID sensors. We will start by discussing the principle of operation of SQUIDs, placing the emphasis on their application as ultrasensitive detectors for small localized magnetic signals. We will continue by reviewing a number of existing devices based on different kinds of Josephson junctions and materials, focusing on their advantages and drawbacks. The last sections are left for applications of nanoSQUIDs in the fields of scanning SQUID microscopy and magnetic particle characterization, placing special stress on the investigation of individual magnetic nanoparticles.

  20. A noise simulator for eLISA: Migrating LISA Pathfinder knowledge to the eLISA mission

    OpenAIRE

    Armano, M.; Audley, H.; Auger, G.; Baird, J.; Binetruy, P.; Born, Michael; Bortoluzzi, D.; Brandt, N.; Bursi, A.; Caleno, M.; Cavalleri, A.; Cesarini, A.; Cruise, M.; Danzmann, Karsten; Diepholz, I.

    2015-01-01

    We present a new technical simulator for the eLISA mission, based on state space modeling techniques and developed in MATLAB. This simulator computes the coordinate and velocity over time of each body involved in the constellation, i.e. the spacecraft and its test masses, taking into account the different disturbances and actuations. This allows studying the contribution of instrumental noises and system imperfections on the residual acceleration applied on the TMs, the latter reflecting the ...

  1. Time-delay interferometry for LISA

    International Nuclear Information System (INIS)

    Tinto, Massimo; Estabrook, F.B.; Armstrong, J.W.

    2002-01-01

    LISA (Laser Interferometer Space Antenna) is a mission to detect and study low-frequency cosmic gravitational radiation through its influence on the phases or frequencies of laser beams exchanged between three remote spacecraft. We previously showed how, with lasers of identical frequencies on stationary spacecraft, the measurement of twelve time series of Doppler shifts could be combined to cancel exactly the phase noise of the lasers and the Doppler fluctuations due to noninertial motions of the six optical benches, while preserving gravitational wave signals. Here we generalize those results on gravitational wave detection with time-delay interferometry to the expected LISA instrument. The six lasers have different center frequencies (in the nominal LISA configuration these center frequencies may well differ by several hundred megahertz) and the distances between spacecraft pairs will change with time (these slowly varying orbital Doppler shifts are expected to be up to tens of megahertz). We develop time-delay data combinations which, as previously, preserve gravitational waves and exactly cancel the leading noise source (phase fluctuations of the six lasers); these data combinations then imply transfer functions for the remaining system noises. Using these, we plot frequency and phase power spectra for modeled system noises in the unequal Michelson combination X and the symmetric Sagnac combination ζ. Although optical bench noise can no longer be cancelled exactly, with the current LISA specifications it is suppressed to negligible levels. It is known that the presently anticipated laser center frequency differences and the orbital Doppler drifts introduce another source of phase noise, arising from the onboard oscillators required to track the photodetector fringes. For the presently planned mission, our analysis indeed demonstrates that noise from current-generation ultrastable oscillators would, if uncorrected, dominate the LISA noise budget. To meet the

  2. LISA Sources in Milky Way Globular Clusters

    Science.gov (United States)

    Kremer, Kyle; Chatterjee, Sourav; Breivik, Katelyn; Rodriguez, Carl L.; Larson, Shane L.; Rasio, Frederic A.

    2018-05-01

    We explore the formation of double-compact-object binaries in Milky Way (MW) globular clusters (GCs) that may be detectable by the Laser Interferometer Space Antenna (LISA). We use a set of 137 fully evolved GC models that, overall, effectively match the properties of the observed GCs in the MW. We estimate that, in total, the MW GCs contain ˜21 sources that will be detectable by LISA. These detectable sources contain all combinations of black hole (BH), neutron star, and white dwarf components. We predict ˜7 of these sources will be BH-BH binaries. Furthermore, we show that some of these BH-BH binaries can have signal-to-noise ratios large enough to be detectable at the distance of the Andromeda galaxy or even the Virgo cluster.

  3. Weak-light phase locking for LISA

    International Nuclear Information System (INIS)

    McNamara, Paul W

    2005-01-01

    The long armlengths of the LISA interferometer, and the finite aperture of the telescope, lead to an optical power attenuation of ∼10 -10 of the transmitted to received light. Simple reflection at the end of the arm is therefore not an optimum interferometric design. Instead, a local laser is offset phase locked to the weak incoming beam, transferring the phase information of the incoming to the outgoing light. This paper reports on an experiment to characterize a weak-light phase-locking scheme suitable for LISA in which a diode-pumped, Nd:YAG, non-planar ring oscillator (NPRO) is offset phase locked to a low-power (13 pW) frequency stabilized master NPRO. Preliminary results of the relative phase noise of the slave laser shows shot noise limited performance above 0.4 Hz. Excess noise is observed at lower frequencies, most probably due to thermal effects in the optical arrangement and phase-sensing electronics

  4. A new integrated microwave SQUID circuit design

    International Nuclear Information System (INIS)

    Erne, S.N.; Finnegan, T.F.

    1980-01-01

    In this paper we consider the design and operation of a planar thin-film rf-SQUID circuit which can be realized via microwave-integrated-circuit (MIC) techniques and which differs substantially from pervious microwave SQUID configurations involving either mechanical point-contact or cylindrical thin-film micro-bridge geometries. (orig.)

  5. Data Analysis for the LISA Pathfinder Mission

    Science.gov (United States)

    Thorpe, James Ira

    2009-01-01

    The LTP (LISA Technology Package) is the core part of the Laser Interferometer Space Antenna (LISA) Pathfinder mission. The main goal of the mission is to study the sources of any disturbances that perturb the motion of the freely-falling test masses from their geodesic trajectories as well as 10 test various technologies needed for LISA. The LTP experiment is designed as a sequence of experimental runs in which the performance of the instrument is studied and characterized under different operating conditions. In order to best optimize subsequent experimental runs, each run must be promptly analysed to ensure that the following ones make best use of the available knowledge of the instrument ' In order to do this, all analyses must be designed and tested in advance of the mission and have sufficient built-in flexibility to account for unexpected results or behaviour. To support this activity, a robust and flexible data analysis software package is also required. This poster presents two of the main components that make up the data analysis effort: the data analysis software and the mock-data challenges used to validate analysis procedures and experiment designs.

  6. LISA and LISA PathFinder, the endeavour to detect low frequency GWs

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, H [Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BW (United Kingdom); Boatella, C [Institut d' Estudis Espacials de Catalunya (IEEC), Edifici Nexus, Gran Capita 2-4, 08034 Barcelona (Spain); Chmeissani, M [Institut de Fisica d' Altes Energies (IFAE), Edifici C, Universitat Autonoma de Barcelona, 08193 Bellaterra (Barcelona) (Spain); Conchillo, A [Institut d' Estudis Espacials de Catalunya (IEEC), Edifici Nexus, Gran Capita 2-4, 08034 Barcelona (Spain); Garcia-Berro, E [Institut d' Estudis Espacials de Catalunya (IEEC), Edifici Nexus, Gran Capita 2-4, 08034 Barcelona (Spain); Grimani, C [Universita degli Studi di Urbino, and INFN Florence, Istituto di Fisica, Via Santa Chiara 27, 61029 Urbino (Italy); Hajdas, W [Department of Particles and Matter, Paul Scherrer Institut, ODRA 120, 5232 Villigen (Switzerland); Lobo, A [Institut d' Estudis Espacials de Catalunya (IEEC), Edifici Nexus, Gran Capita 2-4, 08034 Barcelona (Spain); Martinez, L [AtIpic, Parc Tecnologic del Valles, 08290 Cerdanyola del Valles, Barcelona (Spain); Nofrarias, M [Institut d' Estudis Espacials de Catalunya (IEEC), Edifici Nexus, Gran Capita 2-4, 08034 Barcelona (Spain); Ortega, J A [Institut d' Estudis Espacials de Catalunya (IEEC), Edifici Nexus, Gran Capita 2-4, 08034 Barcelona (Spain); Puigdengoles, C [Institut de Fisica d' Altes Energies (IFAE), Edifici C, Universitat Autonoma de Barcelona, 08193 Bellaterra (Barcelona) (Spain); Ramos-Castro, J [Departament d' Enginyeria Electronica, UPC, Campus Nord, Edif. C4, Jordi Girona 1-3, 08034 Barcelona (Spain); Sanjuan, J [Institut d' Estudis Espacials de Catalunya (IEEC), Edifici Nexus, Gran Capita 2-4, 08034 Barcelona (Spain); Wass, P [Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BW (United Kingdom); Xirgu, X [Institut d' Estudis Espacials de Catalunya (IEEC), Edifici Nexus, Gran Capita 2-4, 08034 Barcelona (Spain)

    2007-05-15

    This is a review about LISA and its technology demonstrator, LISAPathFinder. We first describe the conceptual problems which need to be overcome in order to set up a working interferometric detector of low frequency Gravitational Waves (GW), then summarise the solutions to them as currently conceived by the LISA mission team. This will show that some of these solutions require new technological abilities which are still under development, and which need proper test before being fully implemented. LISAPathFinder (LPF) is the the testbed for such technologies. The final part of the paper will address the ideas and concepts behind the PathFinder as well as their impact on LISA.

  7. LISA and LISA PathFinder, the endeavour to detect low frequency GWs

    International Nuclear Information System (INIS)

    Araujo, H; Boatella, C; Chmeissani, M; Conchillo, A; Garcia-Berro, E; Grimani, C; Hajdas, W; Lobo, A; Martinez, L; Nofrarias, M; Ortega, J A; Puigdengoles, C; Ramos-Castro, J; Sanjuan, J; Wass, P; Xirgu, X

    2007-01-01

    This is a review about LISA and its technology demonstrator, LISAPathFinder. We first describe the conceptual problems which need to be overcome in order to set up a working interferometric detector of low frequency Gravitational Waves (GW), then summarise the solutions to them as currently conceived by the LISA mission team. This will show that some of these solutions require new technological abilities which are still under development, and which need proper test before being fully implemented. LISAPathFinder (LPF) is the the testbed for such technologies. The final part of the paper will address the ideas and concepts behind the PathFinder as well as their impact on LISA

  8. Ground-based self-gravity tests for LISA Pathfinder and LISA

    International Nuclear Information System (INIS)

    Trenkel, C; Warren, C; Wealthy, D

    2009-01-01

    Gravitational coupling between the free-falling test masses and the surrounding spacecraft is one of the dominant noise sources for both LISA Pathfinder and LISA. At present, there are no plans to verify any of the self-gravity requirements by test, on the ground. Here, we explore the possibilities of conducting such tests, using a customised torsion balance. We discuss the main sources of systematic and statistical uncertainty present in such a set-up. Our preliminary assessment indicates that the sensitivity is sufficient to carry out meaningful self-gravity tests.

  9. Data analysis and source modelling for LISA

    International Nuclear Information System (INIS)

    Shang, Yu

    2014-01-01

    The gravitational waves are one of the most important predictions in general relativity. Besides of the directly proof of the existence of GWs, there are already several ground based detectors (such as LIGO, GEO, etc) and the planed future space mission (such as: LISA) which are aim to detect the GWs directly. GW contain a large amount of information of its source, extracting these information can help us dig out the physical property of the source, even open a new window for understanding the Universe. Hence, GW data analysis will be a challenging task in seeking the GWs. In this thesis, I present two works about the data analysis for LISA. In the first work, we introduce an extended multimodal genetic algorithm which utilizes the properties of the signal and the detector response function to analyze the data from the third round of mock LISA data challenge. We have found all five sources present in the data and recovered the coalescence time, chirp mass, mass ratio and sky location with reasonable accuracy. As for the orbital angular momentum and two spins of the Black Holes, we have found a large number of widely separated modes in the parameter space with similar maximum likelihood values. The performance of this method is comparable, if not better, to already existing algorithms. In the second work, we introduce an new phenomenological waveform model for the extreme mass ratio inspiral system. This waveform consists of a set of harmonics with constant amplitude and slowly evolving phase which we decompose in a Taylor series. We use these phenomenological templates to detect the signal in the simulated data, and then, assuming a particular EMRI model, estimate the physical parameters of the binary with high precision. The results show that our phenomenological waveform is very feasible in the data analysis of EMRI signal.

  10. SQUIDs in biomagnetism: a roadmap towards improved healthcare

    Science.gov (United States)

    Körber, Rainer; Storm, Jan-Hendrik; Seton, Hugh; Mäkelä, Jyrki P.; Paetau, Ritva; Parkkonen, Lauri; Pfeiffer, Christoph; Riaz, Bushra; Schneiderman, Justin F.; Dong, Hui; Hwang, Seong-min; You, Lixing; Inglis, Ben; Clarke, John; Espy, Michelle A.; Ilmoniemi, Risto J.; Magnelind, Per E.; Matlashov, Andrei N.; Nieminen, Jaakko O.; Volegov, Petr L.; Zevenhoven, Koos C. J.; Höfner, Nora; Burghoff, Martin; Enpuku, Keiji; Yang, S. Y.; Chieh, Jen-Jei; Knuutila, Jukka; Laine, Petteri; Nenonen, Jukka

    2016-11-01

    -to-noise ratio (SNR) is low compared with high-field MRI. Realistic solutions to this problem are proposed, including implementing sensors with a noise level of 0.1 fT Hz-1/2. A logical and exciting prospect (chapter 5) is to combine MEG and ULF MRI into a single system in which both signal sources are detected with the same array of SQUIDs. A prototype system is described. The combination of MEG and ULF MRI allows one to obtain structural images of the head concurrently with the recording of brain activity. Since all MEG images require an MRI to determine source locations underlying the MEG signal, the combined modality would give a precise registration of the two images; the combination of MEG with high-field MRI can produce registration errors as large as 5 mm. The use of multiple sensors for ULF MRI increases both the SNR and the field of view. Chapter 6 describes another potentially far-reaching application of ULF MRI, namely neuronal current imaging (NCI) of the brain. Currently available neuronal imaging techniques include MEG, which is fast but has relatively poor spatial resolution, perhaps 10 mm, and functional MRI (fMRI) which has a millimeter resolution but is slow, on the order of seconds, and furthermore does not directly measure neuronal signals. NCI combines the ability of direct measurement of MEG with the spatial precision of MRI. In essence, the magnetic fields generated by neural currents shift the frequency of the magnetic resonance signal at a location that is imaged by the three-dimensional magnetic field gradients that form the basis of MRI. The currently achieved sensitivity of NCI is not quite sufficient to realize its goal, but it is close. The realization of NCI would represent a revolution in functional brain imaging. Improved techniques for immunoassay are always being sought, and chapter 7 introduces an entirely new topic, magnetic nanoparticles for immunoassay. These particles are bio-funtionalized, for example with a specific antibody which binds

  11. Performance of arm locking in LISA

    International Nuclear Information System (INIS)

    McKenzie, Kirk; Spero, Robert E.; Shaddock, Daniel A.

    2009-01-01

    For the Laser Interferometer Space Antenna (LISA) to reach its design sensitivity, the coupling of the free-running laser frequency noise to the signal readout must be reduced by more than 14 orders of magnitude. One technique employed to reduce the laser frequency noise will be arm locking, where the laser frequency is locked to the LISA arm length. In this paper we detail an implementation of arm locking. We investigate orbital effects (changing arm lengths and Doppler frequencies), the impact of errors in the Doppler knowledge that can cause pulling of the laser frequency, and the noise limit of arm locking. Laser frequency pulling is examined in two regimes: at lock acquisition and in steady state. The noise performance of arm locking is calculated with the inclusion of the dominant expected noise sources: ultrastable oscillator (clock) noise, spacecraft motion, and shot noise. We find that clock noise and spacecraft motion limit the performance of dual arm locking in the LISA science band. Studying these issues reveals that although dual arm locking [A. Sutton and D. A. Shaddock, Phys. Rev. D 78, 082001 (2008)] has advantages over single (or common) arm locking in terms of allowing high gain, it has disadvantages in both laser frequency pulling and noise performance. We address this by proposing a modification to the dual arm-locking sensor, a hybrid of common and dual arm-locking sensors. This modified dual arm-locking sensor has the laser frequency pulling characteristics and low-frequency noise coupling of common arm locking, but retains the control system advantages of dual arm locking. We present a detailed design of an arm-locking controller and perform an analysis of the expected performance when used with and without laser prestabilization. We observe that the sensor phase changes beneficially near unity-gain frequencies of the arm-locking controller, allowing a factor of 10 more gain than previously believed, without degrading stability. With a time

  12. The LISA Pathfinder DMU and Radiation Monitor

    Energy Technology Data Exchange (ETDEWEB)

    Canizares, P; Conchillo, A; Gesa, L; Lloro, I; Lobo, A; Mateos, I; Sopuerta, Carlos F [Institut de Ciencies de l' Espai, CSIC, Facultat de Ciencies, Torre C5 parell, 08193 Bellaterra (Spain); Chmeissani, M [Institut de Fisica d' Altes Energies (IFAE), Edifici CN, UAB Campus, 08193 Bellaterra (Spain); Diaz-Aguilo, M; GarcIa-Berro, E; Gibert, F [Institut d' Estudis Espacials de Catalunya (IEEC), Edifici Nexus, Gran Capita 2-4, 08034 Barcelona (Spain); Grimani, C [Universita degli Studi di Urbino, MFI Department, Via Santa Chiara 27, 61029 Urbino, and INFN Florence (Italy); Nofrarias, M [Max-Planck-Institut fuer Gravitationsphysik (Albert-Einstein-Institut), Callinstrasse 38, D-30167 Hannover (Germany); Ramos-Castro, J [Departament d' Enginyeria Electronica, UPC, Campus Nord, Edifici C4, Jordi Girona 1-3, 08034 Barcelona (Spain); Sanjuan, J [Department of Physics, University of Florida, NPB-22258 PO Box 118 440, Gainesville, FL 32611-8440 (United States); Araujo, H M; Wass, P, E-mail: lobo@ieec.fcr.es [High Energy Physics Blackett Laboratory, Prince Consort Road, Imperial College London, London SW7 2BW (United Kingdom)

    2011-05-07

    The LISA Pathfinder DMU (Data Management Unit) flight model was formally accepted by ESA and ASD on 11 February 2010, after all hardware and software tests had been successfully completed. The diagnostics items are scheduled to be delivered by the end of 2010. In this paper, we review the requirements and performance of this instrumentation, specially focusing on the Radiation Monitor and the DMU, as well as the status of their programmed use during mission operations, on which work is ongoing at the time of writing.

  13. LISA Beyond Einstein: From the Big Bang to Black Holes. LISA Technology Development at GSFC

    Science.gov (United States)

    Thorpe, James Ira

    2008-01-01

    This viewgraph presentation reviews the work that has been ongoing at the Goddard Space Flight Center (GSFC) in the development of the technology to be used in the Laser Interferometer Space Antenna (LISA) spacecrafts. The prime focus of LISA technology development efforts at NASA/GSFC has been in LISA interferometry. Specifically efforts have been made in the area of laser frequency noise mitigation. Laser frequency noise is addressed through a combination of stabilization and common-mode rejection. Current plans call for two stages of stabilization, pre-stabilization to a local frequency reference and further stabilization using the constellation as a frequency reference. In order for these techniques to be used simultaneously, the pre-stabilization step must provide an adjustable frequency offset. This presentation reports on a modification to the standard modulation/demodulation technique used to stabilize to optical cavities that generates a frequency-tunable reference from a fixed length cavity. This technique requires no modifications to the cavity itself and only minor modifications to the components. The measured noise performance and dynamic range of the laboratory prototype meet the LISA requirements.

  14. Squid based beam current meter

    International Nuclear Information System (INIS)

    Kuchnir, M.

    1983-01-01

    A SQUID based beam current meter has the capability of measuring the current of a beam with as little as 30 x 155 antiprotons (with a signal to noise ratio of 2). If low noise dc current is used to cancel most of the beam or an up-down counter is used to count auto-resets this sensitivity will be available at any time in the acumulation process. This current meter will therefore be a unique diagnostic tool for optimizing the performance of several Tev I components. Besides requiring liquid helium it seems that its only drawback is not to follow with the above sensitivity a sudden beam change larger than 16 μA, something that could be done using a second one in a less sensitive configuration

  15. Optical testbed for the LISA phasemeter

    International Nuclear Information System (INIS)

    Schwarze, T S; Fernández Barranco, G; Penkert, D; Gerberding, O; Heinzel, G; Danzmann, K

    2016-01-01

    The planned spaceborne gravitational wave detector LISA will allow the detection of gravitational waves at frequencies between 0.1 mHz and 1 Hz. A breadboard model for the metrology system aka the phasemeter was developed in the scope of an ESA technology development project by a collaboration between the Albert Einstein Institute, the Technical University of Denmark and the Danish industry partner Axcon Aps. It in particular provides the electronic readout of the main interferometer phases besides auxiliary functions. These include clock noise transfer, ADC pilot tone correction, inter-satellite ranging and data transfer. Besides in LISA, the phasemeter can also be applied in future satellite geodesy missions. Here we show the planning and advances in the implementation of an optical testbed for the full metrology chain. It is based on an ultra-stable hexagonal optical bench. This bench allows the generation of three unequal heterodyne beatnotes with a zero phase combination, thus providing the possibility to probe the phase readout for non-linearities in an optical three signal test. Additionally, the utilization of three independent phasemeters will allow the testing of the auxiliary functions. Once working, components can individually be replaced with flight-qualified hardware in this setup. (paper)

  16. Optical testbed for the LISA phasemeter

    Science.gov (United States)

    Schwarze, T. S.; Fernández Barranco, G.; Penkert, D.; Gerberding, O.; Heinzel, G.; Danzmann, K.

    2016-05-01

    The planned spaceborne gravitational wave detector LISA will allow the detection of gravitational waves at frequencies between 0.1 mHz and 1 Hz. A breadboard model for the metrology system aka the phasemeter was developed in the scope of an ESA technology development project by a collaboration between the Albert Einstein Institute, the Technical University of Denmark and the Danish industry partner Axcon Aps. It in particular provides the electronic readout of the main interferometer phases besides auxiliary functions. These include clock noise transfer, ADC pilot tone correction, inter-satellite ranging and data transfer. Besides in LISA, the phasemeter can also be applied in future satellite geodesy missions. Here we show the planning and advances in the implementation of an optical testbed for the full metrology chain. It is based on an ultra-stable hexagonal optical bench. This bench allows the generation of three unequal heterodyne beatnotes with a zero phase combination, thus providing the possibility to probe the phase readout for non-linearities in an optical three signal test. Additionally, the utilization of three independent phasemeters will allow the testing of the auxiliary functions. Once working, components can individually be replaced with flight-qualified hardware in this setup.

  17. Detection of Micrometeoroids with LISA Pathfinder

    Science.gov (United States)

    Thorpe, Ira; Littenberg, Tyson; Janchez, Diego; Baker, John; The LISA Pathfinder Team Team

    2017-01-01

    The LISA Pathfinder mission (LPF), a joint ESA/NASA technology demonstration mission currently operating at the Sun-Earth L1 point, contains the most precise accelerometry system ever flown. Analysis suggests that LPF should have sufficient sensitivity to detect impacts of small micrometeoroids and dust through their transfer of momentum to the spacecraft. Moreover, LPF's ability to fully resolve both the linear and angular momentum transfer in three dimensions allows a magnitude, direction, and location to be estimated for each impact. We present preliminary results from a systematic search of the LISA Pathfinder data for such impacts and discuss the prospects for using these and future results to inform models of the formation and evolution of dust populations in the inner solar system. These models have wide applicability to both pure and applied space science, ranging from the physics of planet formation and dynamics of minor Solar System bodies to estimates of the micrometeorite hazard for future spacecraft. 2017 NASA Science Innovation Fund.

  18. LISA as a dark energy probe

    International Nuclear Information System (INIS)

    Arun, K G; Mishra, Chandra Kant; Iyer, B R; Sinha, Siddhartha; Van Den Broeck, Chris; Sathyaprakash, B S

    2009-01-01

    Recently, it has been shown that the inclusion of higher signal harmonics in the inspiral signals of binary supermassive black holes (SMBH) leads to dramatic improvements in the parameter estimation with Laser Interferometer Space Antenna (LISA). In particular, the angular resolution becomes good enough to identify the host galaxy or galaxy cluster, in which case the redshift can be determined by electromagnetic means. The gravitational wave signal also provides the luminosity distance with high accuracy, and the relationship between this and the redshift depends sensitively on the cosmological parameters, such as the equation-of-state parameter w = p DE /ρ DE of dark energy. Using binary SMBH events at z < 1 with appropriate masses and orientations, one would be able to constrain w to within a few per cent. We show that, if the measured sky location is folded into the error analysis, the uncertainty on w goes down by an additional factor of 2-3, leaving weak lensing as the only limiting factor in using LISA as a dark energy probe.

  19. New version of toroidal SQUID sensor

    International Nuclear Information System (INIS)

    Zarembinski, S.; Kachniarz, J.

    1983-01-01

    A report is given on the design and fabrication of a mechanically stable and thermal shock resistant SQUID sensor. The sensor is vacuum sealed while the access to the adjustment of its point contact is left open

  20. YBCO SQUIDs with unconventional current phase relation

    International Nuclear Information System (INIS)

    Bauch, T.; Johansson, J.; Cedergren, K.; Lindstroem, T.; Lombardi, F.

    2007-01-01

    We have studied the dynamics of YBa 2 Cu 3 O 7-δ (YBCO) dc sperconducting quantum interference devices (SQUIDs) characterized by an unconventional Josephson current phase relation (CPR). We have focused on SQUID configurations with Josephson junctions where the lobe of the order parameter in one electrode is facing a node in the other electrode. This order parameter arrangement should enhance the appearance of a sin(2φ) term in the CPR. The response of the critical current of the dc SQUID, under the effect of an external magnetic field, has been measured in temperature, down to 20 mK. Our experimental data have been compared with numerical simulations of the SQUIDs dynamics by considering a CPR of a single junction of the form I(φ) = I I sin(φ) - I II sin(2φ) where I I and I II are, respectively, the first and second harmonic component. In our devices the values of the sin(2φ) term are such that the fundamental state of the SQUID is naturally double degenerate. This is of great relevance for applications of d-wave SQUIDs in quantum information processing

  1. Interferometry for the LISA technology package LTP: an update

    International Nuclear Information System (INIS)

    Heinzel, G; Bogenstahl, J; Braxmaier, C; Danzmann, K; Garcia, A; Guzman, F; Hough, J; Hoyland, D; Jennrich, O; Killow, C; Robertson, D; Sodnik, Z; Steier, F; Ward, H; Wand, V

    2006-01-01

    This paper gives an update on the status of the LISA technology package (LTP) which is to be launched in 2009 by ESA as a technology demonstration mission for the spaceborne gravitational wave observatory LISA. The dominant noise source in the interferometer prototype has been investigated and improved such that it is now comfortably below its budget at all frequencies

  2. Fundamentals of the LISA stable flight formation

    International Nuclear Information System (INIS)

    Dhurandhar, S V; Nayak, K Rajesh; Koshti, S; Vinet, J-Y

    2005-01-01

    The joint NASA-ESA mission, LISA, relies crucially on the stability of the three-spacecraft constellation. Each of the spacecraft is in heliocentric orbit forming a stable triangle. In this paper we explicitly show with the help of the Clohessy-Wiltshire equations that any configuration of spacecraft lying in the planes making angles of ±60 0 with the ecliptic and given suitable initial velocities within the plane, can be made stable in the sense that the inter-spacecraft distances remain constant to first order in the dimensions of the configuration compared with the distance to the Sun. Such analysis would be useful in order to carry out theoretical studies on the optical links, simulators, etc

  3. Squids: principles and basic applications in experimental physics

    International Nuclear Information System (INIS)

    Ocio, M.

    1990-01-01

    The basic principles and the description of the technical aspects of SQUIDs (Superconducting Quantum Interference Devices) are described. The applications of SQUIDs in experimental researches and low temperature physics experiments are given. The concepts of fluxoid quantization in a superconductor and Josephson tunnelling are reviewed. The principles, the operation, the noise and the different configurations of r.f. and direct current bias SQUIDs are summarized. The principal characteristics of several SQUIDs are reported

  4. Electronics for a Next-Generation SQUID-Based Time-Domain Multiplexing System

    International Nuclear Information System (INIS)

    Reintsema, C. D.; Doriese, W. R.; Hilton, G. C.; Irwin, K. D.; Krinsky, J. W.; Adams, J. S.; Baker, R.; Bandler, S. R.; Kelly, R. L.; Kilbourne, C. A.; Porter, F. S.; Figueroa-Feliciano, E.; Wikus, P.

    2009-01-01

    A decade has elapsed since the design, development and realization of a SQUID-based time-division multiplexer at NIST. During this time the system has been used extensively for low-temperature-detector-array measurements. Concurrently, there have been substantial advancements both in detector array and commercial electronic component technology. The relevance and applicability of the technology has blossomed as well, often accompanied by more demanding measurement requirements. These factors have motivated a complete redesign of the NIST room-temperature read-out electronics. The redesign has leveraged advancements in component technology to achieve new capabilities better suited to the SQUID multiplexers and detector arrays being realized today. As examples of specific performance enhancements, the overall system bandwidth has been increased by a factor of four (a row switching rate of 6.24 MHz), the compactness has been increased by over a factor of two (a higher number of detector columns and rows per circuit board), and there are two high speed outputs per column (allowing fast switching of SQUID offsets in addition to digital feedback). The system architecture, design implementations, and performance advantages of the new system will be discussed. As an application example, the science chain flight electronics for the Micro-X High Resolution Microcalorimeter X-ray Imaging Rocket will be described as both a motivation for, and a direct implementation of the new system.

  5. SQUID multiplexing using baseband feedback for space application of transition-edge sensor microcalorimeters

    Energy Technology Data Exchange (ETDEWEB)

    Takei, Y; Yamasaki, N Y; Hirakoso, W; Kimura, S; Mitsuda, K, E-mail: takei@astro.isas.jaxa.j [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, 229-8510 (Japan)

    2009-11-15

    A microcalorimeter array based on a transition-edge sensor (TES) thermometer is a promising imaging spectrometer for use in future x-ray astronomy missions. A TES microcalorimeter achieves {approx}<5 eV energy resolution and an array of >100 pixels also provides a moderate imaging capability. For a large format array, signal multiplexing at the low temperature stage is mandatory in order to reduce heat loads from cold stage preamplifiers and through wirings. We are developing frequency division multiplexing (FDM). In FDM, each TES is ac-biased with a different carrier frequency. Signals from several pixels are summed and then read out by one dc SQUID (superconducting quantum interference device). The maximum number of multiplexed pixels is limited by the bandwidth of a SQUID in a flux-locked loop. Assuming 1 m cable length between the room temperature and the cold stage, the bandwidth is only <1 MHz with a standard flux-locked loop, due to the delay and phase shift of wirings. We report our development of baseband feedback, a new feedback scheme that overcomes the bandwidth limitation. In baseband feedback, the signal ({approx}<10 kHz) from the TES is sent back to the SQUID after the phase of carrier frequency ({approx}1 MHz) has been adjusted. We demonstrated open-loop gain of 8 for 10 kHz signal at 5 MHz carrier frequency, which indicates the possibility of {approx}40-pixel multiplexing of the TES signal.

  6. Charge Management in LISA Pathfinder: The Continuous Discharging Experiment

    Science.gov (United States)

    Ewing, Becca Elizabeth

    2018-01-01

    Test mass charging is a significant source of excess force and force noise in LISA Pathfinder (LPF). The planned design scheme for mitigation of charge induced force noise in LISA is a continuous discharge by UV light illumination. We report on analysis of a charge management experiment on-board LPF conducted during December 2016. We discuss the measurement of test mass charging noise with and without continuous UV illumination, in addition to the dynamic response in the continuous discharge scheme. Results of the continuous discharge system will be discussed for their application to operating LISA with lower test mass charge.

  7. The investigation of rf-squids at liquid nitrogen temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Polushkin, V N; Vasiliev, B V [Joint Inst. for Nuclear Research, Dubna (USSR)

    1989-12-01

    One- and two-hole YBCO ceramic rf-squids operating at liquid nitrogen temperatures have been developed. The main squid parameters: self-inductance, white noise level and magnetic flux resolution were measured. The directly measured external field sensitivity for one-hole squid was at the level of 100 fT/{radical}Hz. (orig.).

  8. The use of (double) relaxation oscillation SQUIDs as a sensor

    NARCIS (Netherlands)

    van Duuren, M.J.; Brons, G.C.S.; Kattouw, H.; Flokstra, Jakob; Rogalla, Horst

    1997-01-01

    Relaxation Oscillation SQUIDs (ROSs) and Double Relaxation Oscillation SQUIDs (DROSs) are based on relaxation oscillations that are induced in hysteretic dc SQUIDs by an external L-R shunt. The relaxation frequency of a ROS varies with the applied flux Φ, whereas the output of a DROS is a dc

  9. Computer model for noise in the dc Squid

    International Nuclear Information System (INIS)

    Tesche, C.D.; Clarke, J.

    1976-08-01

    A computer model for the dc SQUID is described which predicts signal and noise as a function of various SQUID parameters. Differential equations for the voltage across the SQUID including the Johnson noise in the shunted junctions are integrated stepwise in time

  10. Well coupled, low noise, dc SQUIDS

    International Nuclear Information System (INIS)

    Muhlfelder, B.; Beall, J.A.; Cromar, M.W.; Johnson, W.W.; Ono, R.H.

    1985-01-01

    The authors have designed, fabricated, and tested a Double Transformer (DT) coupled dc SQUID (Superconducting Quantum Interference Device) with low noise, an input inductance of 1μH and a smooth input-output characteristic. A transmission line model is presented to explain a resonance in the input-output characteristic of early versions of this device. Guided by the results of numerical simulations a new version of this device has been built and tested. Experimental results are presented that show that the resonance can be moved to a higher voltage by reducing the area of the SQUID loop. The voltage-external flux characteristic of some of these new devices agrees to within 10% with computer simulations. The minimum detectable energy per unit bandwidth (MDE) referred to the SQUID loop, is 10h, where h is Planck's constant. Computer simulations indicate an MDE of 6h

  11. Parameter tolerance of the SQUID bootstrap circuit

    International Nuclear Information System (INIS)

    Zhang Guofeng; Dong Hui; Xie Xiaoming; Jiang Mianheng; Zhang Yi; Krause, Hans-Joachim; Braginski, Alex I; Offenhäusser, Andreas

    2012-01-01

    We recently demonstrated and analysed the voltage-biased SQUID bootstrap circuit (SBC) conceived to suppress the preamplifier noise contribution in the absence of flux modulation readout. Our scheme contains both the additional voltage and current feedbacks. In this study, we analysed the tolerance of the SBC noise suppression performance to spreads in SQUID and SBC circuit parameters. Analytical results were confirmed by experiments. A one-time adjustable current feedback can be used to extend the tolerance to spreads such as those caused by the integrated circuit fabrication process. This should help to improve the fabrication yield of SBC devices integrated on one chip—as required for multi-channel SQUID systems.

  12. High Tc Josephson Junctions, SQUIDs and magnetometers

    International Nuclear Information System (INIS)

    Clarke, J.

    1991-01-01

    There has recently been considerable progress in the state-of-the-art of high-T c magnetometers based on dc SQUIDs (Superconducting Quantum Interference Devices). This progress is due partly to the development of more manufacturable Josephson junctions, making SQUIDs easier to fabricate, and partly to the development of multiturn flux transformers that convert the high sensitivity of SQUIDs to magnetic flux to a correspondingly high sensitivity to magnetic field. Needless to say, today's high-T c SQUIDs are still considerably less sensitive than their low-T c counterparts, particularly at low frequencies (f) where their level of 1/f noise remains high. Nonetheless, the performance of the high-T c devices has now reached the point where they are adequate for a number of the less demanding applications; furthermore, as we shall see, at least modest improvements in performance are expected in the near future. In this article, the author outlines these various developments. This is far from a comprehensive review of the field, however, and, apart from Sec. 2, he describes largely his own work. He begins in Sec. 2 with an overview of the various types of Josephson junctions that have been investigated, and in Sec. 3, he describes some of the SQUIDs that have been tested, and assess their performance. Section 4 discuss the development of the multilayer structures essential for an interconnect technology, and, in particular, for crossovers and vias. Section 5 shows how this technology enables one to fabricate multiturn flux transformers which, in turn, can be coupled to SQUIDs to make magnetometers. The performance and possible future improvements in these magnetometers are assessed, and some applications mentioned

  13. Dual-Cylinder Laser Reference Cavities for LISA Project

    Data.gov (United States)

    National Aeronautics and Space Administration — "Summary: The Laser Interferometer Space Antenna (LISA) mission is under consideration by NASA and ESA as a joint mission to study gravitational wave signals from a...

  14. Gravitational Reference Sensor Front-End Electronics Simulator for LISA

    International Nuclear Information System (INIS)

    Meshksar, Neda; Ferraioli, Luigi; Mance, Davor; Zweifel, Peter; Giardini, Domenico; Ten Pierick, Jan

    2017-01-01

    At the ETH Zurich we are developing a modular simulator that provides a realistic simulation of the Front End Electronics (FEE) for LISA Gravitational Reference Sensor (GRS). It is based on the GRS FEE-simulator already implemented for LISA Pathfinder. It considers, in particular, the non-linearity and the critical details of hardware, such as the non-linear multiplicative noise caused by voltage reference instability, test mass charging and detailed actuation and sensing algorithms. We present the simulation modules, considering the above-mentioned features. Based on the ETH GRS FEE-simulator for LISA Pathfinder we aim to develop a modular simulator that provides a realistic simulation of GRS FEE for LISA. (paper)

  15. SiGe Integrated Circuit Developments for SQUID/TES Readout

    Science.gov (United States)

    Prêle, D.; Voisin, F.; Beillimaz, C.; Chen, S.; Piat, M.; Goldwurm, A.; Laurent, P.

    2018-03-01

    SiGe integrated circuits dedicated to the readout of superconducting bolometer arrays for astrophysics have been developed since more than 10 years at APC. Whether for Cosmic Microwave Background (CMB) observations with the QUBIC ground-based experiment (Aumont et al. in astro-ph.IM, 2016. arXiv:1609.04372) or for the Hot and Energetic Universe science theme with the X-IFU instrument on-board of the ATHENA space mission (Barret et al. in SPIE 9905, space telescopes & instrumentation 2016: UV to γ Ray, 2016. https://doi.org/10.1117/12.2232432), several kinds of Transition Edge Sensor (TES) (Irwin and Hilton, in ENSS (ed) Cryogenic particle detection, Springer, Berlin, 2005) arrays have been investigated. To readout such superconducting detector arrays, we use time or frequency domain multiplexers (TDM, FDM) (Prêle in JINST 10:C08015, 2016. https://doi.org/10.1088/1748-0221/10/08/C08015) with Superconducting QUantum Interference Devices (SQUID). In addition to the SQUID devices, low-noise biasing and amplification are needed. These last functions can be obtained by using BiCMOS SiGe technology in an Application Specific Integrated Circuit (ASIC). ASIC technology allows integration of highly optimised circuits specifically designed for a unique application. Moreover, we could reach very low-noise and wide band amplification using SiGe bipolar transistor either at room or cryogenic temperatures (Cressler in J Phys IV 04(C6):C6-101, 1994. https://doi.org/10.1051/jp4:1994616). This paper discusses the use of SiGe integrated circuits for SQUID/TES readout and gives an update of the last developments dedicated to the QUBIC telescope and to the X-IFU instrument. Both ASIC called SQmux128 and AwaXe are described showing the interest of such SiGe technology for SQUID multiplexer controls.

  16. LISA and its in-flight test precursor SMART-2

    International Nuclear Information System (INIS)

    Vitale, S.; Bender, P.; Brillet, A.; Buchman, S.; Cavalleri, A.; Cerdonio, M.; Cruise, M.; Cutler, C.; Danzmann, K.; Dolesi, R.; Folkner, W.; Gianolio, A.; Jafry, Y.; Hasinger, G.; Heinzel, G.; Hogan, C.; Hueller, M.; Hough, J.; Phinney, S.; Prince, T.; Richstone, D.; Robertson, D.; Rodrigues, M.; Ruediger, A.; Sandford, M.; Schilling, R.; Shoemaker, D.; Schutz, B.; Stebbins, R.; Stubbs, C.; Sumner, T.; Thorne, K.; Tinto, M.; Touboul, P.; Ward, H.; Weber, W.; Winkler, W.

    2002-01-01

    LISA will be the first space-home gravitational wave observatory. It aims to detect gravitational waves in the 0.1 mHz/1 Hz range from sources including galactic binaries, super-massive black-hole binaries, capture of objects by super-massive black-holes and stochastic background. LISA is an ESA approved Cornerstone Mission foreseen as a joint ESA-NASA endeavour to be launched in 2010-11. The principle of operation of LISA is based on laser ranging of test-masses under pure geodesic motion. Achieving pure geodesic motion at the level requested for LISA, 3x10 -15 ms -2 /√Hz at 0.1 mHz, is considered a challenging technological objective. To reduce the risk, both ESA and NASA are pursuing an in-flight test of the relevant technology. The goal of the test is to demonstrate geodetic motion within one order of magnitude from the LISA performance. ESA has given this test as the primary goal of its technology dedicated mission SMART-2 with a launch in 2006. This paper describes the basics of LISA, its key technologies, and its in-flight precursor test on SMART-2

  17. A UV LED-based Charge Management System for LISA

    Science.gov (United States)

    Conklin, John W.; Chilton, Andrew; Olatunde, Taiwo Janet; Apple, Stephen; Parry, Samantha; Ciani, Giacomo; Wass, Peter; Mueller, Guido

    2018-01-01

    The Laser Interferometer Space Antenna (LISA) will be the first space instrument to observe gravitational waves in the millihertz frequency band. LISA consists of three Sun-orbiting spacecraft that form an equilateral triangle, with each side measuring 2.5 million kilometers in length. Each spacecraft houses two free-floating test masses, which are protected from all disturbing forces so that they follow pure geodesics in spacetime. A drag-free control system commands micronewton thrusters to force the spacecraft to fly in formation with the test masses and laser interferometers measure the minute variations in the distance, or light travel time, between these free-falling test masses caused by gravitational waves. The LISA observatory, with a planned launch in the early 2030s, is led by the European Space Agency with significant contributions from NASA. Recently, NASA has initiated strategic investments in key LISA technologies that will likely become U.S. flight hardware contributions to this ground-breaking mission. One of these payload elements is the Charge Management System (CMS), which controls the electric potential of the test masses relative to their housings to reduce spurious force noise acting on the test masses to below the required level. This talk, presented by University of Florida team that leads the CMS development, will describe this vital U.S. contribution to the LISA mission in the context of the envisioned LISA payload architecture and its in-flight sensitivity to gravitational waves.

  18. Design of a hysteretic SQUID as the readout for a dc SQUID

    International Nuclear Information System (INIS)

    Gershenson, M.

    1991-01-01

    This paper present a design for an optimal hysteretic SQUID readout circuit for a DC SQUID, thus eliminating the need for bulky output transformers or resonance matching circuits. The hysteretic readout system, which is based in part on standard sampling theory, is compared to another similar system and shown to be superior in terms of slew rate and immunity of electromagnetic interference. The circuit will be useful in optimizing the performance of biomagnetic systems

  19. Double-barrier junction based dc SQUID

    NARCIS (Netherlands)

    Bartolomé, M.E.; Brinkman, Alexander; Flokstra, Jakob; Golubov, Alexandre Avraamovitch; Rogalla, Horst

    2000-01-01

    dc SQUIDs based on double-barrier Nb/Al/AlOx/Al/AlOx/Al/Nb junctions (DBSQs) have been fabricated and tested for the first time. The current–voltage curves have been measured at temperatures down to 1.4 K. The critical current, Ic, dependence on the temperature T is partially described by the

  20. One Period of Exploration with the Squid.

    Science.gov (United States)

    Bradley, James V.; Ng, Andrew

    1997-01-01

    Presents a lab that can be offered after students have learned the basic anatomy and physiology of the various phyla, the primary objective of which is to explore and apply their acquired knowledge to a new situation. Involves exploring the anatomy and life-style of the squid. (JRH)

  1. Squid Dissection: From Pen to Ink.

    Science.gov (United States)

    Brown, Cindy; Kisiel, Jim

    2003-01-01

    Introduces students to dissection, which is an important part of scientific discovery. Students not only gain an understanding of the anatomy of a squid, but also develop a sense of responsibility and respect for the animal that they are using as a learning tool. (Author/SOE)

  2. Distinguishing Between Formation Channels for Binary Black Holes with LISA

    Science.gov (United States)

    Breivik, Katelyn; Rodriguez, Carl L.; Larson, Shane L.; Kalogera, Vassiliki; Rasio, Frederic A.

    2017-01-01

    The recent detections of GW150914 and GW151226 imply an abundance of stellar-mass binary-black-hole mergers in the local universe. While ground-based gravitational-wave detectors are limited to observing the final moments before a binary merges, space-based detectors, such as the Laser Interferometer Space Antenna (LISA), can observe binaries at lower orbital frequencies where such systems may still encode information about their formation histories. In particular, the orbital eccentricity and mass of binary black holes in the LISA frequency band can be used together to discriminate between binaries formed in isolation in galactic fields and those formed in dense stellar environments such as globular clusters. In this letter, we explore the orbital eccentricity and mass of binary-black-hole populations as they evolve through the LISA frequency band. Overall we find that there are two distinct populations discernible by LISA. We show that up to ~90% of binaries formed either dynamically or in isolation have eccentricities measurable by LISA. Finally, we note how measured eccentricities of low-mass binary black holes evolved in isolation could provide detailed constraints on the physics of black-hole natal kicks and common-envelope evolution.

  3. LISA Pathfinder: hardware tests and their input to the mission

    Science.gov (United States)

    Audley, Heather

    The Laser Interferometer Space Antenna (LISA) is a joint ESA-NASA mission for the first space-borne gravitational wave detector. LISA aims to detect sources in the 0.1mHz to 1Hz range, which include supermassive black holes and galactic binary stars. Core technologies required for the LISA mission, including drag-free test mass control, picometre interferometry and micro-Newton thrusters, cannot be tested on-ground. Therefore, a precursor satellite, LISA Pathfinder, has been developed as a technology demonstration mission. The preparations for the LISA Pathfinder mission have reached an exciting stage. Tests of the engineering model of the optical metrology system have recently been completed at the Albert Einstein Institute, Hannover, and flight model tests are now underway. Significantly, they represent the first complete integration and testing of the space-qualified hardware and are the first tests on system level. The results and test procedures of these campaigns will be utilised directly in the ground-based flight hardware tests, and subsequently within in-flight operations. In addition, they allow valuable testing of the data analysis methods using the MatLab based LTP data analysis toolbox. This contribution presents an overview of the test campaigns calibration, control and perfor-mance results, focusing on the implications for the Experimental Master Plan which provides the basis for the in-flight operations and procedures.

  4. SISTEM OTENTIKASI UNTUK SQUID BERBASIS WEB

    Directory of Open Access Journals (Sweden)

    Febriliyan Samopa

    2006-07-01

    Full Text Available Dalam sebuah jaringan komputer terdapat bermacam-macam tipe user dengan berbagi tingkatan yang berbeda yang juga dibutuhkan perlakuan yang berbeda pada tiap user yang disesuaikan dengan kebutuhan dalam menggunakan akses web, baik berupa http, ftp, gopher, dan lain-lain. Dimana masing-masing user memiliki skala prioritas dalam penggunaan bandwidth, jumlah koneksi maksimum, waktu koneksi, ukuran file maksimum, situs yang tidak boleh diakses dan lain-lain. Tujuan dari penelitian ini adalah membuat sebuah perangkat lunak yang dapat melakukan otentikasi user berdasarkan data konfigurasi yang disimpan dalam basisdata. Selain itu, perangkat lunak yang dibuat dapat memproses request dari client berdasarkan data konfigurasi dengan lebih cepat. Permasalahan yang mucul adalah bagaimana merancang dan membuat suatu perangkat lunak yang dapat melakukan otentikasi user berdasarkan data konfigurasi yang diambil dari basisdata, serta dapat memproses request dari client dengan lebih cepat berdasarkan hak akses yang dimilikinya.Dalam penelitian ini didesain dan diimplementasikan suatu sistem otentikasi user dengan mengambil data user yang tersimpan dalam basisdata MySQL. Disamping itu, dilakukan rekayasa pada beberapa rutin proses yang terdapat dalam squid proxy, supaya proses-proses dapat melakukan pengambilan data konfigurasi yang dialihkan dan disimpan dalam basisdata MySQL. Data konfigurasi ini didasarkan pada pembagian hak akses yang dimiliki oleh masing-masing grup user. Antarmuka berbasis web digunakan sebagai salah satu layanan bagi admin untuk mempermudah pengelolaan dan pengolahan data konfigurasi yang dibuat.Berdasarkan uji coba yang telah dilakukan, terbukti sistem yang dibuat dapat bekerja dengan baik dan tidak melenceng dari fungsi asli sebelum dilakukan perubahan. Bahkan pada penanganan request client yang berukuran besar, kinerja squid mengalami peningkatan dalam hal kecepatan proses yang dibutuhkan. Sebagai contoh, request client pada  file

  5. Data combinations accounting for LISA spacecraft motion

    International Nuclear Information System (INIS)

    Shaddock, Daniel A.; Tinto, Massimo; Estabrook, Frank B.; Armstrong, J.W.

    2003-01-01

    The laser interferometer space antenna is an array of three spacecraft in an approximately equilateral triangle configuration which will be used as a low-frequency gravitational wave detector. We present here new generalizations of the Michelson- and Sagnac-type time-delay interferometry data combinations. These combinations cancel laser phase noise in the presence of different up and down propagation delays in each arm of the array, and slowly varying systematic motion of the spacecraft. The gravitational wave sensitivities of these generalized combinations are the same as previously computed for the stationary cases, although the combinations are now more complicated. We introduce a diagrammatic representation to illustrate that these combinations are actually synthesized equal-arm interferometers

  6. Accreting Double White Dwarf Binaries: Implications for LISA

    Energy Technology Data Exchange (ETDEWEB)

    Kremer, Kyle; Breivik, Katelyn; Larson, Shane L.; Kalogera, Vassiliki, E-mail: kremer@u.northwestern.edu, E-mail: katelyn.breivik@northwestern.edu, E-mail: vicky@northwestern.edu, E-mail: s.larson@northwestern.edu [Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), Department of Physics and Astronomy, Northwestern University 2145 Sheridan Road, Evanston, IL 60201 (United States)

    2017-09-10

    We explore the long-term evolution of mass-transferring white dwarf (WD) binaries undergoing both direct-impact and disk accretion and explore implications of such systems to gravitational-wave (GW) astronomy. We cover a broad range of initial component masses and show that these systems, the majority of which lie within the Laser Interferometer Space Antenna ( LISA ) sensitivity range, exhibit prominent negative orbital frequency evolution (chirp) for a significant fraction of their lifetimes. Using a galactic population synthesis, we predict ∼2700 of these systems will be observable with a negative chirp of 0.1 yr{sup −2} by a space-based GW detector like LISA . We also show that detections of mass-transferring double WD systems by LISA may provide astronomers with unique ways of probing the physics governing close compact object binaries.

  7. Accreting Double White Dwarf Binaries: Implications for LISA

    Science.gov (United States)

    Kremer, Kyle; Breivik, Katelyn; Larson, Shane L.; Kalogera, Vassiliki

    2017-09-01

    We explore the long-term evolution of mass-transferring white dwarf (WD) binaries undergoing both direct-impact and disk accretion and explore implications of such systems to gravitational-wave (GW) astronomy. We cover a broad range of initial component masses and show that these systems, the majority of which lie within the Laser Interferometer Space Antenna (LISA) sensitivity range, exhibit prominent negative orbital frequency evolution (chirp) for a significant fraction of their lifetimes. Using a galactic population synthesis, we predict ˜2700 of these systems will be observable with a negative chirp of 0.1 yr-2 by a space-based GW detector like LISA. We also show that detections of mass-transferring double WD systems by LISA may provide astronomers with unique ways of probing the physics governing close compact object binaries.

  8. Bayesian statistics for the calibration of the LISA Pathfinder experiment

    International Nuclear Information System (INIS)

    Armano, M; Freschi, M; Audley, H; Born, M; Danzmann, K; Diepholz, I; Auger, G; Binetruy, P; Bortoluzzi, D; Brandt, N; Fitzsimons, E; Bursi, A; Caleno, M; Cavalleri, A; Cesarini, A; Dolesi, R; Ferroni, V; Cruise, M; Dunbar, N; Ferraioli, L

    2015-01-01

    The main goal of LISA Pathfinder (LPF) mission is to estimate the acceleration noise models of the overall LISA Technology Package (LTP) experiment on-board. This will be of crucial importance for the future space-based Gravitational-Wave (GW) detectors, like eLISA. Here, we present the Bayesian analysis framework to process the planned system identification experiments designed for that purpose. In particular, we focus on the analysis strategies to predict the accuracy of the parameters that describe the system in all degrees of freedom. The data sets were generated during the latest operational simulations organised by the data analysis team and this work is part of the LTPDA Matlab toolbox. (paper)

  9. Accreting Double White Dwarf Binaries: Implications for LISA

    International Nuclear Information System (INIS)

    Kremer, Kyle; Breivik, Katelyn; Larson, Shane L.; Kalogera, Vassiliki

    2017-01-01

    We explore the long-term evolution of mass-transferring white dwarf (WD) binaries undergoing both direct-impact and disk accretion and explore implications of such systems to gravitational-wave (GW) astronomy. We cover a broad range of initial component masses and show that these systems, the majority of which lie within the Laser Interferometer Space Antenna ( LISA ) sensitivity range, exhibit prominent negative orbital frequency evolution (chirp) for a significant fraction of their lifetimes. Using a galactic population synthesis, we predict ∼2700 of these systems will be observable with a negative chirp of 0.1 yr −2 by a space-based GW detector like LISA . We also show that detections of mass-transferring double WD systems by LISA may provide astronomers with unique ways of probing the physics governing close compact object binaries.

  10. LISA package user guide. Part II: LISA (Long Term Isolation Safety Assessment) program description and user guide

    International Nuclear Information System (INIS)

    Prado, P.; Saltelli, A.; Homma, T.

    1992-01-01

    This manual is subdivided into three parts. In this second part, this document describes the LISA (Long term Isolation Safety Assessment) Code and its submodels. LISA is a tool for analysis of the safety of an underground disposal of nuclear waste. It has the capability to handle nuclide chain of arbitrary length and to evaluate the migration of nuclide through a geosphere medium composed of an arbitrary number of segments. LISA makes use of Monte Carlo methodology to evaluate the uncertainty in the quantity being assessed (eg dose) arising from the uncertainty in the model input parameters. In the present version LISA is equipped with a very simple source term submodel, a relatively complex geosphere and a simplified biosphere. The code is closely associated with its statistical pre-processor code (PREP), which generates the input Monte Carlo sample from the assigned parameter probability density functions and with its post-processor code (SPOP) which provides useful statistics on the output sample (uncertainty and sensitivity analysis). This report describes the general structure of LISA, its subroutines and submodels, the code input ant output files. It is intended to provide the user with enough information to know and run the code as well as the capacity to incorporate different submodels. 15 refs., 6 figs

  11. Image processing for HTS SQUID probe microscope

    International Nuclear Information System (INIS)

    Hayashi, T.; Koetitz, R.; Itozaki, H.; Ishikawa, T.; Kawabe, U.

    2005-01-01

    An HTS SQUID probe microscope has been developed using a high-permeability needle to enable high spatial resolution measurement of samples in air even at room temperature. Image processing techniques have also been developed to improve the magnetic field images obtained from the microscope. Artifacts in the data occur due to electromagnetic interference from electric power lines, line drift and flux trapping. The electromagnetic interference could successfully be removed by eliminating the noise peaks from the power spectrum of fast Fourier transforms of line scans of the image. The drift between lines was removed by interpolating the mean field value of each scan line. Artifacts in line scans occurring due to flux trapping or unexpected noise were removed by the detection of a sharp drift and interpolation using the line data of neighboring lines. Highly detailed magnetic field images were obtained from the HTS SQUID probe microscope by the application of these image processing techniques

  12. Macroscopic quantum tunneling in a dc SQUID

    International Nuclear Information System (INIS)

    Chen, Y.C.

    1986-01-01

    The theory of macroscopic quantum tunneling is applied to a current-biased dc SQUID whose dynamics can be described by a two-dimensional mechanical system with a dissipative environment. Based on the phenomenological model proposed by Caldeira and Leggett, the dissipative environment is represented by a set of harmonic oscillators coupling to the system. After integrating out the environmental degrees of freedom, an effective Euclidean action is found for the two-dimensional system. The action is used to provide the quantum tunneling rate formalism for the dc SQUID. Under certain conditions, the tunneling rate reduces to that of a single current-biased Josephson junction with an adjustable effective critical current

  13. The Breadboard model of the LISA telescope assembly

    Science.gov (United States)

    Lucarelli, S.; Scheulen, D.; Kemper, D.; Sippel, R.; Verlaan, A.; Hogenhuis, H.; Ende, D.

    2017-11-01

    The primary goal of the LISA mission is the detection of gravitational waves from astronomical sources in a frequency range of 10-4 to 1 Hz. This requires operational stabilities in the picometer range as well as highly predictable mechanical distortions upon cooling down, outgassing in space, and gravity release. In March 2011 ESA announced a new way forward for the Lclass candidate missions, including LISA. ESA and the scientific community are now studying options for European-only missions that offer a significant reduction of the costs, while maintaining their core science objectives. In this context LISA has become the New Gravitational wave Observatory (NGO). Despite this reformulation, the need for dimensional stability in the picometer range remains valid, and ESA have continued the corresponding LISA Technology Development Activities (TDA's) also in view of NGO. In such frame Astrium GmbH and xperion (Friedrichshafen, Germany) have designed and manufactured an ultra-stable CFRP breadboard of the LISA telescope in order to experimentally demonstrate that the structure and the M1 & M2 mirror mounts are fulfilling the LISA requirements in the mission operational thermal environment. Suitable techniques to mount the telescope mirrors and to support the M1 & M2 mirrors have been developed, with the aim of measuring a system CTE of less than 10-7 K-1 during cooling down to -80°C. Additionally to the stringent mass and stiffness specifications, the required offset design makes the control of relative tilts and lateral displacements between the M1 and M2 mirrors particularly demanding. The thermo-elastic performance of the telescope assembly is going to be experimentally verified by TNO (Delft, The Netherlands) starting from the second half of 2012. This paper addresses challenges faced in the design phase, shows the resulting hardware and present first outcomes of the test campaign performed at TNO.

  14. Fundamental characteristics of the QFP measured by the dc SQUID

    International Nuclear Information System (INIS)

    Shimizu, N.; Harada, Y.; Miyamoto, N.; Hosoya, M.; Goto, E.

    1989-01-01

    This paper describes the fundamental characteristics of the Quantum Flux Parametron (QFP) measured by a new method in which the output signals of the QFP are detected with a dc SQUID. The dc SQUID linearly and continuously converts the output current of the QFP to voltage, allowing the output signal of the QFP to be measured as the voltage of the dc SQUID. Thus, the fundamental characteristics of the QFP have been experimentally confirmed in detail

  15. Hot electron effect in the dc SQUID

    International Nuclear Information System (INIS)

    Wellstood, F.C.; Clarke, J.; Urbina, C.

    1989-01-01

    The authors have investigated the temperature dependence of the noise in thin-film dc Superconducting Quantum Interference Devices (SQUIDs) down to 20 mK. The white noise measured in the early versions of our SQUIDs did not decrease as the bath temperature was lowered below 150 mK. They have attributed this saturation to a hot electron effect in the thin-film AuCu resistors shunting the Josephson junctions. A theoretical investigation showed that the temperature of the electrons in the shunts should be given by T/sub e/ = (P/ΣΩ)/sup 1/5/, where P is the power dissipated in the shunts, Ω is the shunt volume, and Σ is a proportionality constant. Experimentally, the authors found Σ=(2.4+-0.6)X10/sup 9/WK/sup -5/m/sup -3/. They have redesigned the shunts, adding large thin-film cooling fins, to increase their volume substantially. This technique has reduced T/sub e/ to about 50 mK, with a corresponding improvement in the sensitivity of the SQUIDs

  16. Directly coupled YBCO dc SQUID magnetometers

    International Nuclear Information System (INIS)

    Petersen, P.R.E.; Shen, Y.Q.; Holst, T.; Larsen, B.H.; Sager, M.P.; Bindslev Hansen, J.

    1999-01-01

    YBa 2 Cu 3 O 7- x magnetometers have been made on 10mmx10mm MgO substrates by directly coupling the magnetometer pick-up loop to a dc SQUID with narrow strip lines. The dc SQUIDs were made with YBa 2 Cu 3 O 7-x step-edge Josephson junctions. The layout of the magnetometer pick-up loop was chosen as a compromise between maximizing the loop effective area and minimizing the loop inductance. The SQUID was designed to have L S ∼100 pH in order to obtain β L =2I 0 L S /Φ 0 approx.= 1 with the single-junction critical current I 0 ∼10 μA. We have made magnetometers with white noise levels down to 55 fT Hz -1/2 and a 1/f knee at 1 Hz (ac biased). Noise measurements were made on a field-cooled magnetometer. The noise measured at 1 Hz when cooled in 'zero field' was 175 fT Hz -1/2 . When cooled in magnetic fields of B = 50 μT and B = 100 μT we measured the noise at 1 Hz to be 430 fT Hz -1 2 and 1.3 pT Hz -1/2 , respectively. (author)

  17. Analysis of Squid Net Fisheries Business Production

    Directory of Open Access Journals (Sweden)

    Herna Octivia Damayanti

    2017-03-01

    Full Text Available Squid net is one of alternatives to replace trawl net in Pati regency. The purposes of the research are 1 to determine the influence factors, 2 to analyze the return to scale, 3 to analyze cost and return.The research location in Juwana Subdistrict particularly Bakaran Kulon, Dukutalit, Bajomulyo and Bendar Villages. The research conducted on October 2015 to June 2016. The number of final samples was 36, while the formulation of management strategies used 15 samples by snowball sampling. Data analysis techniques used 1 Cobb Douglas production function, 2 revenue-cost ratio analysis. The results of the research are 1 significant inputs for production factor are long trip, Solar fuel, the number of crew and lights. 2 the return to scale of squid net bussiness in Juwana subdistrict Pati regency is -0.231 means decreasing to scale. 3 the R/C ratio of scenario II more profitable for squid net crews than  scenario I.

  18. Inference on inspiral signals using LISA MLDC data

    International Nuclear Information System (INIS)

    Roever, Christian; Stroeer, Alexander; Bloomer, Ed; Christensen, Nelson; Clark, James; Hendry, Martin; Messenger, Chris; Meyer, Renate; Pitkin, Matt; Toher, Jennifer; Umstaetter, Richard; Vecchio, Alberto; Veitch, John; Woan, Graham

    2007-01-01

    In this paper, we describe a Bayesian inference framework for the analysis of data obtained by LISA. We set up a model for binary inspiral signals as defined for the Mock LISA Data Challenge 1.2 (MLDC), and implemented a Markov chain Monte Carlo (MCMC) algorithm to facilitate exploration and integration of the posterior distribution over the nine-dimensional parameter space. Here, we present intermediate results showing how, using this method, information about the nine parameters can be extracted from the data

  19. LISA Pathfinder: Optical Metrology System monitoring during operations

    Science.gov (United States)

    Audley, Heather E.; LISA Pathfinder Collaboration

    2017-05-01

    The LISA Pathfinder (LPF) mission has demonstrated excellent performance. In addition to having surpassed the main mission goals, data has been collected from the various subsystems throughout the duration of the mission. This data is a valuable resource, both for a more complete understanding of the LPF satellite and the differential acceleration measurements, as well as for the design of the future Laser Interferometer Space Antenna (LISA) mission. Initial analysis of the Optical Metrology System (OMS) data was performed as part of daily system monitoring, and more in-depth analyses are ongoing. This contribution presents an overview of these activities along with an introduction to the OMS.

  20. E. Yiannopoulou on Lisa Blackman’s The Body.

    Directory of Open Access Journals (Sweden)

    2009-11-01

    Full Text Available Blackman, Lisa. The Body. Oxford and New York: Berg, 2008. 160 pp. “Is there anything natural about the human body?” (1. This is how Lisa Blackman begins her all too daunting task of reviewing and critically evaluating what has come to be known as “body theory” in the field of sociology. Carefully picking her way among numerous theories on the corporeal that have been produced across the humanities in the last twenty years, Blackman lays out her problematic from the start by asking to know w...

  1. Preliminary report on the PIXE analysis of the squid statoliths

    International Nuclear Information System (INIS)

    Ikeda, Yuzuru; Arai, Nobuaki; Sakamoto, Wataru; Murayama, Tatsuro; Maeda, Kuniko; Yoshida, Koji.

    1996-01-01

    Micro trace elements in the squid statolith, a calcareous stone which acts as a balancer and hearing, was analyzed with Particle Induced X-ray Emission (PIXE) for the Japanese common squid for the first time. Calcium is the main component of the squid statoliths, which means that squid statolith is the pure calcified structure similar to the fish otolith. Beside Ca, Sr was detected with strong dosage, and some other elements as Mn, Fe, Cu, Zn and As were also detected. Possible assumption of intake of microelements to the statoliths and the suitability of PIXE for statoliths analysis are discussed. (author)

  2. Low noise niobium dc SQUID with a planar input coil

    Science.gov (United States)

    de Waal, V. J.; van den Hamer, P.; Klapwijk, T. M.

    1983-02-01

    A practical all-niobium dc superconducting quantum interference device (SQUID) with a niobium spiral input coil has been developed. The SQUID utilizes submicron Josephson junctions. The best intrinsic energy resolution obtained with a 1-nH SQUID is 4×10-32 J/Hz. A 20-turn 1.2-μH input coil is coupled to a 2.3-nH SQUID with an efficiency of 0.5. The energy resolution with respect to the coil is 1×10-30 J/Hz.

  3. Low noise niobium dc SQUID with a planar input coil

    Energy Technology Data Exchange (ETDEWEB)

    de Waal, V.J.; van den Hamer, P.; Klapwijk, T.M.

    1983-02-15

    A practical all-niobium dc superconducting quantum interference device (SQUID) with a niobium spiral input coil has been developed. The SQUID utilizes submicron Josephson junctions. The best intrinsic energy resolution obtained with a 1-nH SQUID is 4 x 10/sup -32/ J/Hz. A 20-turn 1.2-..mu..H input coil is coupled to a 2.3-nH SQUID with an efficiency of 0.5. The energy resolution with respect to the coil is 1 x 10/sup -30/ J/Hz.

  4. Antioxidant and antimicrobial activities of squid ink powder

    OpenAIRE

    Fatimah Zaharah, M.Y.; Rabeta, M.S.

    2017-01-01

    Economic development in Malaysia has led to increasing quantity and complexity of generated waste or by-product. The main objective of this study is to investigate the antioxidant and antimicrobial activities of squid ink powder. The squid ink was collected from fresh squid and dried using freeze dryer before it was ground into powder. The yield of squid ink was 22.82% after freeze-drying which was 69.37g in amount. Proximate composition analysis as well as two total antioxidant activity assa...

  5. Allometry indicates giant eyes of giant squid are not exceptional.

    Science.gov (United States)

    Schmitz, Lars; Motani, Ryosuke; Oufiero, Christopher E; Martin, Christopher H; McGee, Matthew D; Gamarra, Ashlee R; Lee, Johanna J; Wainwright, Peter C

    2013-02-18

    The eyes of giant and colossal squid are among the largest eyes in the history of life. It was recently proposed that sperm whale predation is the main driver of eye size evolution in giant squid, on the basis of an optical model that suggested optimal performance in detecting large luminous visual targets such as whales in the deep sea. However, it is poorly understood how the eye size of giant and colossal squid compares to that of other aquatic organisms when scaling effects are considered. We performed a large-scale comparative study that included 87 squid species and 237 species of acanthomorph fish. While squid have larger eyes than most acanthomorphs, a comparison of relative eye size among squid suggests that giant and colossal squid do not have unusually large eyes. After revising constants used in a previous model we found that large eyes perform equally well in detecting point targets and large luminous targets in the deep sea. The eyes of giant and colossal squid do not appear exceptionally large when allometric effects are considered. It is probable that the giant eyes of giant squid result from a phylogenetically conserved developmental pattern manifested in very large animals. Whatever the cause of large eyes, they appear to have several advantages for vision in the reduced light of the deep mesopelagic zone.

  6. Growth and optical development of the ocular lens of the squid (Sepioteuthis lessoniana).

    Science.gov (United States)

    Sivak, J G; West, J A; Campbell, M C

    1994-09-01

    Lens focal properties (spherical aberration), diameter and relative anterior/posterior proportions were measured photographically for Japanese squid (Sepioteuthis lessoniana) at ages 4-6 weeks, 7-9 weeks and 7-8 months. The measures involved photographing the refractive effects of lenses in a physiological solution, with and without an index matching fluid (polyvinylpyrroloidone solution), on a parallel array of fine helium-neon laser beams. Spherical aberration was determined from measurement of back vertex distance. Similar measurements were made on lenses from the eyes of cuttlefish (Sepia officinalis). The cephalopod lens develops as hemispheric halves from separate ectodermal sources. The posterior component contributes, on average, about 60% of axial lens diameter in S. lessoniana of all ages and 55% in S. officinalis. However, these proportions vary widely in both species. All lenses of both species show that spherical aberration is neutralized, although small variations in back vertex distance (positive and negative spherical aberration) were measured. Preliminary measures indicate that the refractive index distribution within the cephalopod lens varies in a manner reminiscent of teleost lenses. Squid lenses from animals 7-9 weeks of age were optimally corrected for spherical aberration. Some squid of this age, from a separate tank, showed a high incidence of cataract development. In each case, lens opacification was caused by deterioration of the posterior lens component.

  7. 240 nm UV LEDs for LISA test mass charge control

    Science.gov (United States)

    Olatunde, Taiwo; Shelley, Ryan; Chilton, Andrew; Serra, Paul; Ciani, Giacomo; Mueller, Guido; Conklin, John

    2015-05-01

    Test Masses inside the LISA Gravitational Reference Sensor must maintain almost pure geodesic motion for gravitational waves to be successfully detected. LISA requires residual test mass accelerations below 3 fm/s2/√Hz at all frequencies between 0.1 and 3 mHz. One of the well-known noise sources is associated with the charges on the test masses which couple to stray electrical potentials and external electromagnetic fields. LISA Pathfinder will use Hg-discharge lamps emitting mostly around 254 nm to discharge the test masses via photoemission in its 2015/16 flight. A future LISA mission launched around 2030 will likely replace the lamps with newer UV-LEDs. Presented here is a preliminary study of the effectiveness of charge control using latest generation UV-LEDs which produce light at 240 nm with energy above the work function of pure Au. Their lower mass, better power efficiency and small size make them an ideal replacement for Hg lamps.

  8. 240 nm UV LEDs for LISA test mass charge control

    International Nuclear Information System (INIS)

    Olatunde, Taiwo; Shelley, Ryan; Chilton, Andrew; Serra, Paul; Ciani, Giacomo; Mueller, Guido; Conklin, John

    2015-01-01

    Test Masses inside the LISA Gravitational Reference Sensor must maintain almost pure geodesic motion for gravitational waves to be successfully detected. LISA requires residual test mass accelerations below 3 fm/s 2 /√Hz at all frequencies between 0.1 and 3 mHz. One of the well-known noise sources is associated with the charges on the test masses which couple to stray electrical potentials and external electromagnetic fields. LISA Pathfinder will use Hg-discharge lamps emitting mostly around 254 nm to discharge the test masses via photoemission in its 2015/16 flight. A future LISA mission launched around 2030 will likely replace the lamps with newer UV-LEDs. Presented here is a preliminary study of the effectiveness of charge control using latest generation UV-LEDs which produce light at 240 nm with energy above the work function of pure Au. Their lower mass, better power efficiency and small size make them an ideal replacement for Hg lamps. (paper)

  9. Multi-Messenger Astronomy: White Dwarf Binaries, LISA and GAIA

    Science.gov (United States)

    Bueno, Michael; Breivik, Katelyn; Larson, Shane L.

    2017-01-01

    The discovery of gravitational waves has ushered in a new era in astronomy. The low-frequency band covered by the future LISA detector provides unprecedented opportunities for multi-messenger astronomy. With the Global Astrometric Interferometer for Astrophysics (GAIA) mission, we expect to discover about 1,000 eclipsing binary systems composed of a WD and a main sequence star - a sizeable increase from the approximately 34 currently known binaries of this type. In advance of the first GAIA data release and the launch of LISA within the next decade, we used the Binary Stellar Evolution (BSE) code simulate the evolution of White Dwarf Binaries (WDB) in a fixed galaxy population of about 196,000 sources. Our goal is to assess the detectability of a WDB by LISA and GAIA using the parameters from our population synthesis, we calculate GW strength h, and apparent GAIA magnitude G. We can then use a scale factor to make a prediction of how many multi- messenger sources we expect to be detectable by both LISA and GAIA in a galaxy the size of the Milky Way. We create binaries 10 times to ensure randomness in distance assignment and average our results. We then determined whether or not astronomical chirp is the difference between the total chirp and the GW chirp. With Astronomical chirp and simulations of mass transfer and tides, we can gather more information about the internal astrophysics of stars in ultra-compact binary systems.

  10. Professor Lisa Aranson on JA Green (a pioonier artist photographer ...

    African Journals Online (AJOL)

    Jonathan Adagogo Green's photographic and artistic contributions working in his countryside, the Niger Delta of Nigeria is reviewed by Professor Lisa Aranson. Aranson in a public lecture presentation on the stand-point of art history thinks of J.A. Green as having operated in two worlds of which he is said to have initiated in ...

  11. 77 FR 56647 - Lisa Jean Sharp: Debarment Order

    Science.gov (United States)

    2012-09-13

    ... Act (the FD&C Act) permanently debarring Lisa Jean Sharp from providing services in any capacity to a...&C Act. Ms. Sharp was given notice of the proposed permanent debarment and an opportunity to request... drug product under the FD&C Act. The factual basis for this conviction is as follows: Ms. Sharp was the...

  12. Sensitivity and parameter-estimation precision for alternate LISA configurations

    International Nuclear Information System (INIS)

    Vallisneri, Michele; Crowder, Jeff; Tinto, Massimo

    2008-01-01

    We describe a simple framework to assess the LISA scientific performance (more specifically, its sensitivity and expected parameter-estimation precision for prescribed gravitational-wave signals) under the assumption of failure of one or two inter-spacecraft laser measurements (links) and of one to four intra-spacecraft laser measurements. We apply the framework to the simple case of measuring the LISA sensitivity to monochromatic circular binaries, and the LISA parameter-estimation precision for the gravitational-wave polarization angle of these systems. Compared to the six-link baseline configuration, the five-link case is characterized by a small loss in signal-to-noise ratio (SNR) in the high-frequency section of the LISA band; the four-link case shows a reduction by a factor of √2 at low frequencies, and by up to ∼2 at high frequencies. The uncertainty in the estimate of polarization, as computed in the Fisher-matrix formalism, also worsens when moving from six to five, and then to four links: this can be explained by the reduced SNR available in those configurations (except for observations shorter than three months, where five and six links do better than four even with the same SNR). In addition, we prove (for generic signals) that the SNR and Fisher matrix are invariant with respect to the choice of a basis of TDI observables; rather, they depend only on which inter-spacecraft and intra-spacecraft measurements are available

  13. GRS vs. OMS Calibration in LISA Pathfinder Data Analysis

    International Nuclear Information System (INIS)

    Meshksar, Neda; Ferraioli, Luigi; Mance, Davor; Zweifel, Peter; Giardini, Domenico; Ten Pierick, Jan

    2017-01-01

    On board LISA Pathfinder spacecraft the test mass displacement along the main measurement axis is sensed in two different ways: optically and electrostatically. We have monitored the relative calibration between the two measurements during the mission science phase. The trend sensitivity of the relative calibration has been computed for different physical parameters, such as temperature, magnetic field, test mass bias voltage and current. (paper)

  14. LISA data analysis using Markov chain Monte Carlo methods

    International Nuclear Information System (INIS)

    Cornish, Neil J.; Crowder, Jeff

    2005-01-01

    The Laser Interferometer Space Antenna (LISA) is expected to simultaneously detect many thousands of low-frequency gravitational wave signals. This presents a data analysis challenge that is very different to the one encountered in ground based gravitational wave astronomy. LISA data analysis requires the identification of individual signals from a data stream containing an unknown number of overlapping signals. Because of the signal overlaps, a global fit to all the signals has to be performed in order to avoid biasing the solution. However, performing such a global fit requires the exploration of an enormous parameter space with a dimension upwards of 50 000. Markov Chain Monte Carlo (MCMC) methods offer a very promising solution to the LISA data analysis problem. MCMC algorithms are able to efficiently explore large parameter spaces, simultaneously providing parameter estimates, error analysis, and even model selection. Here we present the first application of MCMC methods to simulated LISA data and demonstrate the great potential of the MCMC approach. Our implementation uses a generalized F-statistic to evaluate the likelihoods, and simulated annealing to speed convergence of the Markov chains. As a final step we supercool the chains to extract maximum likelihood estimates, and estimates of the Bayes factors for competing models. We find that the MCMC approach is able to correctly identify the number of signals present, extract the source parameters, and return error estimates consistent with Fisher information matrix predictions

  15. GRS vs. OMS Calibration in LISA Pathfinder Data Analysis

    Science.gov (United States)

    Meshksar, Neda; Ferraioli, Luigi; Mance, Davor; ten Pierick, Jan; Zweifel, Peter; Giardini, Domenico; ">LISA Pathfinder colaboration, LISA Pathfinder spacecraft the test mass displacement along the main measurement axis is sensed in two different ways: optically and electrostatically. We have monitored the relative calibration between the two measurements during the mission science phase. The trend sensitivity of the relative calibration has been computed for different physical parameters, such as temperature, magnetic field, test mass bias voltage and current.

  16. Enhancements to a Superconducting Quantum Interference Device (SQUID) Multiplexer Readout and Control System

    Science.gov (United States)

    Forgione, J.; Benford, D. J.; Buchanan, E. D.; Moseley, S. H.; Rebar, J.; Shafer, R. A.

    2004-01-01

    Far-infrared detector arrays such as the 16x32 superconducting bolometer array for the SAFIRE instrument (flying on the SOFIA airborne observatory) require systems of readout and control electronics to provide translation between a user-driven, digital PC and the cold, analog world of the cryogenic detector. In 2001, the National Institute of Standards and Technology (NIST) developed their Mark III electronics for purposes of control and readout of their 1x32 SQUID Multiplexer chips. We at NASA s Goddard Space Flight Center acquired a Mark 111 system and subsequently designed upgrades to suit our and our collaborators purposes. We developed an arbitrary, programmable multiplexing system that allows the user to cycle through rows in a SQUID array in an infinite number of combinations. We provided hooks in the Mark III system to allow readout of signals from outside the Mark 111 system, such as telescope status information. Finally, we augmented the heart of the system with a new feedback algorithm implementation, flexible diagnostic tools, and informative telemetry.

  17. The Engineering of LISA Pathfinder – the quietest Laboratory ever flown in Space

    International Nuclear Information System (INIS)

    Trenkel, Christian; Wealthy, Dave; Dunbar, Neil; Warren, Carl; Schleicher, Alexander; Ziegler, Tobias; Brandt, Nico; Gerndt, Rüdiger

    2017-01-01

    We review the engineering approach adopted to ensure the required gravitational, magnetic, thermal and residual acceleration stability on-board LISA Pathfinder, and present the in-flight results that have been achieved. Arguably, this stability makes LISA Pathfinder the quietest laboratory ever flown in space. The implications for LISA are also discussed. (paper)

  18. Inductance-dependent characteristics of HTS dc-SQUID amplifiers

    International Nuclear Information System (INIS)

    Mitchell, E.E.; Tilbrook, D.L.; Foley, C.P.; MacFarlane, J.

    2002-01-01

    Full text: We have experimentally determined the transfer function V Φ and noise S Φ of several high temperature superconducting (HTS) dc SQUIDs of increasing loop size, while they were operated (without input flux transformer) in a small-signal-amplifier (open-loop) mode. A primary aim of our investigation was to provide reliable inductance data to aid our design of subsequent magnetometer devices. Flux was induced by means of current injection via a well-defined stripline directly into the SQUID loop. The loop size was systematically incremented in a range of otherwise similar SQUIDs. For each SQUID, the ratio between the induced flux and the injection current (which we define as the coupling inductance of the device, L c ) was measured as a function of the injection path length and the SQUID loop dimensions. Both L c and the derived SQUID self-inductance, L sq , were then compared with theoretical values, and contributions due to kinetic inductance and junction inductance were estimated. Correlations between the inductance data and our measured values of transfer function V Φ and noise S Φ were compared with previous results. Guidelines for optimisation of gradiometer SQUIDs were established, and in particular, the importance of achieving a large value transfer function together with a relatively small inductance was demonstrated. The strong influence of an enhanced transfer function was further emphasised when an order-of-magnitude reduction in noise was achieved by subjecting one of our SQUIDs to an in-house 'ion-beam trimming' process

  19. SQUID magnetometry from nanometer to centimeter length scales

    International Nuclear Information System (INIS)

    Hatridge, Michael J.

    2010-01-01

    The development of Superconducting QUantum Interference Device (SQUID)-based magnetometer for two applications, in vivo prepolarized, ultra-low field MRI of humans and dispersive readout of SQUIDs for micro- and nano-scale magnetometery, are the focus of this thesis.

  20. SQUID magnetometry from nanometer to centimeter length scales

    Energy Technology Data Exchange (ETDEWEB)

    Hatridge, Michael J. [Univ. of California, Berkeley, CA (United States)

    2010-06-01

    The development of Superconducting QUantum Interference Device (SQUID)-based magnetometer for two applications, in vivo prepolarized, ultra-low field MRI of humans and dispersive readout of SQUIDs for micro- and nano-scale magnetometery, are the focus of this thesis.

  1. Universal mechanisms of decoherence of qubit states in a SQUID

    Science.gov (United States)

    Kuklov, A. B.; Chudnovsky, E. M.

    2003-03-01

    Fundamental conservation laws mandate parameter-free generic mechanisms of decoherence of quantum oscillations of the superconducting current in a SQUID [1]. The very fact that the current flows with respect to the ion lattice is shown to result in a decoherence via emission of the transverse sound at the oscillation frequency. For SQUIDs larger than the wavelength of the phonons, this effect can significantly limit the quality factor. The decohering effects of the external mechanical and magnetic noise are shown to be proportional to the total magnetic moment of the SQUID, making small SQUIDs less susceptible to the noise than large SQUIDs. Decoherence due to the emission of photons into the open space and in the presence of the metal shielding has been studied as well. Suggestions of experimental setups with low decoherence have been made. [1] E. M. Chudnovsky and A. B. Kuklov, arXiv:cond-mat/0211246.

  2. Drag force and jet propulsion investigation of a swimming squid

    Directory of Open Access Journals (Sweden)

    Tabatabaei Mahdi

    2015-01-01

    Full Text Available In this study, CAD model of a squid was obtained by taking computer tomography images of a real squid. The model later placed into a computational domain to calculate drag force and performance of jet propulsion. The drag study was performed on the CAD model so that drag force subjected to real squid was revealed at squid’s different swimming speeds and comparison has been made with other underwater creatures (e.g., a dolphin, sea lion and penguin. The drag coefficient (referenced to total wetted surface area of squid is 0.0042 at Reynolds number 1.6x106 that is a %4.5 difference from Gentoo penguin. Besides, jet flow of squid was simulated to observe the flow region generated in the 2D domain utilizing dynamic mesh method to mimic the movement of squid’s mantle cavity.

  3. Current-phase relations and noise in rf biased SQUIDS

    International Nuclear Information System (INIS)

    Jackel, L.D.; Clark, T.D.; Buhrman, R.A.

    1975-01-01

    An investigation was made of the effect of the weak link current-phase relation on noise in rf biased SQUIDs. Non-sinusoidal current-phase relations were observed in various weak links, and these non-sinusoidal relations were correlated with significantly increased intrinsic noise in the SQUID ring. The current-phase relation was also found to affect the amplitude of the rf SQUID ring dissipation. The result of an rf SQUID system noise analysis shows that, due to increased intrinsic noise and reduced ring dissipation, the minimum attainable noise for a SQUID ring having a very non-sinusoidal current-phase relation is considerably greater than for a ring with a sinusoidal relation

  4. Description of charging/discharging processes of the LISA sensors

    International Nuclear Information System (INIS)

    Sumner, Tim; Araujo, Henrique; Davidge, David; Howard, Alex; Lee, Chris; Rochester, Geoff; Shaul, Diana; Wass, Peter

    2004-01-01

    The next generation of gravitational experiments in space is likely to use completely isolated proof-masses. For example, LISA uses proof-masses as mirrors in interferometers for gravitational wave astronomy (Bender et al 1998 Pre-phase A report MPG-233 pp 1-191) and STEP uses proof-masses in Earth orbit for an equivalence principle test (Sumner et al 2003 at press). Nongravitational forces will act on these proof-masses if they become charged, through the action of cosmic rays and solar flare particles for example. This paper examines the consequences of proof-mass charging for LISA, and presents results from using GEANT4 to assess the charging processes. Finally, there is a brief discussion of a means of controlling the charge down to an acceptable level

  5. LISA Sources in Milky Way Globular Clusters.

    Science.gov (United States)

    Kremer, Kyle; Chatterjee, Sourav; Breivik, Katelyn; Rodriguez, Carl L; Larson, Shane L; Rasio, Frederic A

    2018-05-11

    We explore the formation of double-compact-object binaries in Milky Way (MW) globular clusters (GCs) that may be detectable by the Laser Interferometer Space Antenna (LISA). We use a set of 137 fully evolved GC models that, overall, effectively match the properties of the observed GCs in the MW. We estimate that, in total, the MW GCs contain ∼21 sources that will be detectable by LISA. These detectable sources contain all combinations of black hole (BH), neutron star, and white dwarf components. We predict ∼7 of these sources will be BH-BH binaries. Furthermore, we show that some of these BH-BH binaries can have signal-to-noise ratios large enough to be detectable at the distance of the Andromeda galaxy or even the Virgo cluster.

  6. The first mock data challenge for LISA Pathfinder

    Energy Technology Data Exchange (ETDEWEB)

    Monsky, A; Hewitson, M; Wanner, G; Nofrarias, M; Diepholz, I; Danzmann, K [Albert-Einstein-Institut, Max-Planck-Institut fuer Gravitationsphysik und Universitaet Hannover, 30167 Hannover (Germany); Ferraioli, L; Hueller, M; Cavalleri, A; Ciani, G; Dolesi, R [Dipartimento di Fisica, Universita di Trento and INFN, Gruppo Collegato di Trento, 38050 Povo, Trento (Italy); Grynagier, A [Institut fuer Flugmechanik und Flugregelung, 70569 Stuttgart (Germany); Armano, M [European Space Agency, ESAC, Villanueva de la Canada, 28692 Madrid (Spain); Benedetti, M [Dipartimento di Ingegneria dei Materiali e Tecnologie Industriali, Universita di Trento and INFN, Gruppo Collegato di Trento, Mesiano, Trento (Italy); Bogenstahl, J [Department of Physics and Astronomy, University of Glasgow, Glasgow (United Kingdom); Bortoluzzi, D; Bosetti, P; Cristofolini, I [Dipartimento di Ingegneria Meccanica e Strutturale, Universita di Trento and INFN, Gruppo Collegato di Trento, Mesiano, Trento (Italy); Brandt, N [Astrium GmbH, 88039 Friedrichshafen (Germany); Cruise, M, E-mail: anneke.monsky@aei.mpg.d [Department of Physics and Astronomy, University of Birmingham, Birmingham (United Kingdom)

    2009-05-07

    The data analysis of the LISA Technology Package (LTP) will comprise a series of discrete experiments, each focusing on a particular noise measurement or characterization of the instrument in various operating modes. Each of these experiments must be analysed and planned in advance of the mission because the results of a given experiment will have an impact on those that follow. As such, a series of mock data challenges (MDCs) will be developed and carried out with the aim of preparing the analysis tools and optimizing the various planned analyses. The first of these MDCs (MDC1) is a simplified treatment of the dynamics along the axis joining the two test masses onboard LISA Pathfinder. The validation of the dynamical model by predicting the spectra of the interferometer output data is shown, a prediction for the data analysis is calculated and, finally, several simulated interferometer data sets are analysed and calibrated to equivalent out-of-loop test mass acceleration.

  7. Alternative opto-mechanical architectures for the LISA instrument

    Energy Technology Data Exchange (ETDEWEB)

    Weise, Dennis R; Marenaci, Pierangelo; Weimer, Peter; Schulte, Hans Reiner; Gath, Peter; Johann, Ulrich, E-mail: dennis.weise@astrium.eads.ne [EADS Astrium GmbH, Claude-Dornier-Str., 88039 Friedrichshafen (Germany)

    2009-03-01

    As part of the on-going LISA Mission Formulation study under ESA contract, EADS Astrium has recently suggested and investigated a variety of novel LISA payload architectures utilizing so-called 'In-Field Pointing' for accommodation of seasonal constellation dynamics. Here, the annual variation in the angle between the interferometer arms of roughly +-1 deg. is compensated by steering the lines of sight of the individual telescopes with a small actuated mirror located in an intermediate pupil plane inside the telescopes. This introduces a certain flexibility for the overall payload configuration and allows for very compact designs. In particular, it enables a 'single active proof mass' mode with a true cold redundancy between a nominal and a backup GRS system on board each spacecraft, and thus enhances mission robustness.

  8. Recent progress at NASA in LISA formulation and technology development

    International Nuclear Information System (INIS)

    Stebbins, R T

    2008-01-01

    Over the last year, the NASA half of the joint LISA project has focused its efforts on responding to a major review, and advancing the formulation and technology development of the mission. The NAS/NRC Beyond Einstein program assessment review will be described, including the outcome. The basis of the LISA science requirements has changed from detection determined by integrated signal-to-noise ratio to observation determined by uncertainty in the estimation of astrophysical source parameters. The NASA team has further defined the spacecraft bus design, participated in many design trade studies and advanced the requirements flow down and the associated current best estimates of performance. Recent progress in technology development is also summarized

  9. Report on the second Mock LISA data challenge

    International Nuclear Information System (INIS)

    Babak, Stanislav; Porter, Edward K; Baker, John G; Benacquista, Matthew J; Cornish, Neil J; Littenberg, Tyson B; Crowder, Jeff; Cutler, Curt; Vallisneri, Michele; Larson, Shane L; Vecchio, Alberto; Auger, Gerard; Barack, Leor; Blaut, Arkadiusz; Bloomer, Ed; Clark, James; Brown, Duncan A; Fairhurst, Stephen; Christensen, Nelson; Gair, Jonathan R

    2008-01-01

    The Mock LISA data challenges are a program to demonstrate LISA data-analysis capabilities and to encourage their development. Each round of challenges consists of several data sets containing simulated instrument noise and gravitational waves from sources of undisclosed parameters. Participants are asked to analyze the data sets and report the maximum information about the source parameters. The challenges are being released in rounds of increasing complexity and realism: here we present the results of Challenge 2, issued in Jan 2007, which successfully demonstrated the recovery of signals from nonspinning supermassive-black-hole binaries with optimal SNRs between ∼10 and 2000, from ∼20 000 overlapping galactic white-dwarf binaries (among a realistically distributed population of 26 million), and from the extreme-mass-ratio inspirals of compact objects into central galactic black holes with optimal SNRs ∼100

  10. Possible LISA follow-on mission scientific objectives

    International Nuclear Information System (INIS)

    Bender, Peter L; Begelman, Mitchell C; Gair, Jonathan R

    2013-01-01

    A major objective that has been suggested for a follow-on mission to a Laser Interferometer Space Antenna (LISA)-type mission is to investigate more completely how intermediate mass black holes were formed and grew in the early universe, before they evolved into the much more massive black holes at the centers of many galaxies today. The actual design of such a follow-on mission will of course depend on what is observed by a LISA-type mission, such as the recently modified proposal for an evolved LISA mission, with the interferometer arm lengths between spacecraft reduced from 5 million to 1 million km. However, the sensitivity goals of a follow-on mission are likely to be influenced strongly by the desire to be able to see mergers of 10 M ⊙ black holes with roughly 3000 M ⊙ or larger intermediate mass black holes out to as large redshifts as possible. Approximate calculations of the expected signal-to-noise have been made for a possible LISA follow-on mission that was suggested about eight years ago (Bender and Begelman 2005 Trends in Space Science and Cosmic Vision 2020 (Noordwijk: ESA Publications Division) pp 33–38), and was called the Advanced Laser Interferometer Antenna. Based on the calculations, it appears that detections out to a redshift of 10 would be possible for 10 M ⊙ black holes spiraling into perhaps 5000 M ⊙ or larger intermediate mass black holes if the extragalactic gravitational wave background due to close white dwarf binaries is in the currently estimated range. (paper)

  11. Cosmological Backgrounds of Gravitational Waves and eLISA

    OpenAIRE

    Dufaux, Jean-Francois

    2012-01-01

    We review cosmological backgrounds of gravitational waves with a particular attention to the scientific potential of the eLISA/NGO mission. After an overview of cosmological backgrounds and detectors, we consider different cosmological sources that could lead to an observable signal. We then study the backgrounds produced by first-order phase transitions and networks of cosmic strings, assessing the prospects for their detection.

  12. Implementation of time-delay interferometry for LISA

    International Nuclear Information System (INIS)

    Tinto, Massimo; Shaddock, Daniel A.; Sylvestre, Julien; Armstrong, J.W.

    2003-01-01

    We discuss the baseline optical configuration for the Laser Interferometer Space Antenna (LISA) mission, in which the lasers are not free-running, but rather one of them is used as the main frequency reference generator (the master) and the remaining five as slaves, these being phase-locked to the master (the master-slave configuration). Under the condition that the frequency fluctuations due to the optical transponders can be made negligible with respect to the secondary LISA noise sources (mainly proof-mass and shot noises), we show that the entire space of interferometric combinations LISA can generate when operated with six independent lasers (the one-way method) can also be constructed with the master-slave system design. The corresponding hardware trade-off analysis for these two optical designs is presented, which indicates that the two sets of systems needed for implementing the one-way method, and the master-slave configuration, are essentially identical. Either operational mode could therefore be implemented without major implications on the hardware configuration. We then derive the required accuracies of armlength knowledge, time synchronization of the onboard clocks, sampling times and time-shifts needed for effectively implementing time-delay interferometry for LISA. We find that an armlength accuracy of about 16 meters, a synchronization accuracy of about 50 ns, and the time jitter due to a presently existing space qualified clock will allow the suppression of the frequency fluctuations of the lasers below to the level identified by the secondary noise sources. A new procedure for sampling the data in such a way to avoid the problem of having time shifts that are not integer multiples of the sampling time is also introduced, addressing one of the concerns about the implementation of time-delay interferometry

  13. High speed non-latching squid binary ripple counter

    International Nuclear Information System (INIS)

    Silver, A.H.; Phillips, R.R.; Sandell, R.D.

    1985-01-01

    High speed, single flux quantum (SFQ) binary scalers are important components in superconducting analog-to-digital converters (ADC). This paper reviews the concept for a SQUID ADC and the design of an SFQ binary ripple counter, and reports the simulation of key components, and fabrication and performance of non-latching SQUID scalers and SFQ binary ripple counters. The SQUIDs were fabricated with Nb/Nb 2 O 5 /PbIn junctions and interconnected by monolithic superconducting transmission lines and isolation resistors. Each SQUID functioned as a bistable flip-flop with the input connected to the center of the device and the output across one junction. All junctions were critically damped to optimize the pulse response. Operation was verified by observing the dc I-V curves of successive SQUIDs driven by a cw pulse train generated on the same chip. Each SQUID exhibited constant-voltage current steps at 1/2 the voltage of the preceding device as expected from the Josephson voltage-to-frequency relation. Steps were observed only for the same voltage polarity of successive devices and for proper phase bias of the SQUID. Binary frequency division was recorded up to 40GHz for devices designed to operate to 28GHz

  14. UV-LED-based charge control for LISA

    Science.gov (United States)

    Olatunde, Taiwo; Shelley, Ryan; Chilton, Andrew; Ciani, Giacomo; Mueller, Guido; Conklin, John

    2014-03-01

    The test masses inside the LISA gravitational reference sensors (GRS) must maintain almost pure geodesic motion for gravitational waves to be successfully detected. The residual accelerations have to stay below 3fm/s2/rtHz at all frequencies between 0.1 and 3 mHz. One of the well known noise sources is associated with the charges on the test masses which couple to stray electrical potentials and external electro-magnetic fields. The LISA pathfinder (LPF) will use Hg-discharge lamps emitting mostly around 253 nm to discharge the test masses via photoemission in its 2015/16 flight. A future LISA mission launched around 2030 will likely replace the lamps with newer UV-LEDs. UV-LEDs have a lower mass, a better power efficiency, and are smaller than their Hg counterparts. Furthermore, the latest generation produces light at 240 nm, with energy well above the work function of pure gold. I will describe a preliminary design for effective charge control through photoelectric effect by using these LEDs. The effectiveness of this method is verified by taking Quantum Efficiency (QE) measurements which relate the number of electrons emitted to the number of photons incident on the Au test mass surface. This presentation addresses our initial results and future plans which includes implementation and testing in the UF torsion pendulum and space-qualification in a small satellite mission which will launch in the summer of 2014, through a collaboration with Stanford, KACST, and NASA Ames Research Center.

  15. Nested sampling as a tool for LISA data analysis

    International Nuclear Information System (INIS)

    Gair, Jonathan R; Feroz, Farhan; Graff, Philip; Hobson, Michael P; Babak, Stanislav; Petiteau, Antoine; Porter, Edward K

    2010-01-01

    Nested sampling is a technique for efficiently computing the probability of a data set under a particular hypothesis, also called the Bayesian Evidence or Marginal Likelihood, and for evaluating the posterior. MULTINEST is a multi-modal nested sampling algorithm which has been designed to efficiently explore and characterize posterior probability surfaces containing multiple secondary solutions. We have applied the MULTINEST algorithm to a number of problems in gravitational wave data analysis. In this article, we describe the algorithm and present results for several applications of the algorithm to analysis of mock LISA data. We summarise recently published results for a test case in which we searched for two non-spinning black hole binary merger signals in simulated LISA data. We also describe results obtained with MULTINEST in the most recent round of the Mock LISA Data Challenge (MLDC), in which the algorithm was used to search for and characterise both spinning supermassive black hole binary inspirals and bursts from cosmic string cusps. In all these applications, the algorithm found the correct number of signals and efficiently recovered the posterior probability distribution. Moreover, in most cases the waveform corresponding to the best a-posteriori parameters had an overlap in excess of 99% with the true signal.

  16. Nested sampling as a tool for LISA data analysis

    Energy Technology Data Exchange (ETDEWEB)

    Gair, Jonathan R [Institute of Astronomy, Madingley Road, CB3 0HA, Cambridge (United Kingdom); Feroz, Farhan; Graff, Philip; Hobson, Michael P [Astrophysics Group, Cavendish Laboratory, JJ Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Babak, Stanislav; Petiteau, Antoine [Max-Planck-Institut fuer Gravitationsphysik, Am Muehlenberg 1, 14476, Potsdam (Germany); Porter, Edward K, E-mail: jgair@ast.cam.ac.u [APC, UMR 7164, Universite Paris 7 Denis Diderot, 10, rue Alice Domon et Leonie Duquet, 75205 Paris Cedex 13 (France)

    2010-05-01

    Nested sampling is a technique for efficiently computing the probability of a data set under a particular hypothesis, also called the Bayesian Evidence or Marginal Likelihood, and for evaluating the posterior. MULTINEST is a multi-modal nested sampling algorithm which has been designed to efficiently explore and characterize posterior probability surfaces containing multiple secondary solutions. We have applied the MULTINEST algorithm to a number of problems in gravitational wave data analysis. In this article, we describe the algorithm and present results for several applications of the algorithm to analysis of mock LISA data. We summarise recently published results for a test case in which we searched for two non-spinning black hole binary merger signals in simulated LISA data. We also describe results obtained with MULTINEST in the most recent round of the Mock LISA Data Challenge (MLDC), in which the algorithm was used to search for and characterise both spinning supermassive black hole binary inspirals and bursts from cosmic string cusps. In all these applications, the algorithm found the correct number of signals and efficiently recovered the posterior probability distribution. Moreover, in most cases the waveform corresponding to the best a-posteriori parameters had an overlap in excess of 99% with the true signal.

  17. Antioxidant and antimicrobial activities of squid ink powder

    Directory of Open Access Journals (Sweden)

    Fatimah Zaharah, M.Y.

    2017-10-01

    Full Text Available Economic development in Malaysia has led to increasing quantity and complexity of generated waste or by-product. The main objective of this study is to investigate the antioxidant and antimicrobial activities of squid ink powder. The squid ink was collected from fresh squid and dried using freeze dryer before it was ground into powder. The yield of squid ink was 22.82% after freeze-drying which was 69.37g in amount. Proximate composition analysis as well as two total antioxidant activity assays named 2,2-diphenyl-1-picrylhydrazyl (DPPH assay and Ferric Reducing Antioxidant Power (FRAP assay, and antimicrobial analysis were done on the powdered squid ink. The proximate results of squid ink powder were 4.43 ± 0.29% moisture, 62.46 ± 0.62% protein, 3.96 ± 0.08% fat, and 9.29 ± 0.05% ash. Results of DPPH assay showed that water extraction of squid ink powder has the highest 94.87 ± 4.87%, followed by ethanol 67.57 ± 7.55%, and hexane extract 2.10 ± 1.18%. FRAP assay result presented the same trend with water extraction had the highest value of 929.67 ± 2.31 μmol Fe (II / g of sample extract, followed by ethanol extract 201.00 ± 26.29 μmol Fe (II per gram sample and hexane 79.67 ± 12.66 μmol Fe (II / g of sample extract. Both water and ethanol extract showed antimicrobial properties with inhibition range of 7 to 15 mm, respectively. Fresh squid ink had 1.254 × 103 colony forming unit per gram of sample of microbial content. Squid ink powder had protein as major compound and microbial content was below from standard value of fisheries products as stated in Food Act 1983 and Regulation 1985.

  18. MONA, LISA and VINCI Soon Ready to Travel to Paranal

    Science.gov (United States)

    2000-11-01

    First Instruments for the VLT Interferometer Summary A few months from now, light from celestial objects will be directed for the first time towards ESO's Very Large Telescope Interferometer (VLTI) at the Paranal Observatory (Chile). During this "First Light" event and the subsequent test phase, the light will be recorded with a special test instrument, VINCI (VLT INterferometer Commissioning Instrument). The main components of this high-tech instrument are aptly named MONA (a system that combines the light beams from several telescopes by means of optical fibers) and LISA (the infrared camera). VINCI was designed and constructed within a fruitful collaboration between ESO and several research institutes and industrial companies in France and Germany . It is now being assembled at the ESO Headquarters in Garching (Germany) and will soon be ready for installation at the telescope on Paranal. With the VLTI and VINCI, Europe's astronomers are now entering the first, crucial phase of an exciting scientific and technology venture that will ultimately put the world's most powerful optical/IR interferometric facility in their hands . PR Photo 31/00 : VINCI during tests at the ESO Headquarters in Garching. The VLT Interferometer (VLTI) ESO Press Photo 31/00 ESO Press Photo 31/00 [Preview; JPEG: 400 x 301; 43k] [Normal; JPEG: 800 x 602;208xk] [Full-Res; JPEG: 1923 x 1448; 2.2Mb] PR Photo 31/00 shows the various components of the complex VINCI instrument for the VLT Interferometer , during the current tests at the Optical Laboratory at the ESO Headquarters in Garching (Germany). It will later be installed in "clean-room" conditions within the Interferometric Laboratory at the Paranal Observatory. This electronic photo was obtained for documentary purposes. VINCI (VLT INterferometer Commissioning Instrument) is the "First Light" instrument for the Very Large Telescope Interferometer (VLTI) at the Paranal Observatory (Chile). Early in 2001, it will be used for the first tests

  19. Squids old and young: Scale-free design for a simple billboard

    Science.gov (United States)

    Packard, Andrew

    2011-03-01

    Squids employ a large range of brightness-contrast spatial frequencies in their camouflage and signalling displays. The 'billboard' of coloured elements ('spots'=chromatophore organs) in the skin is built autopoietically-probably by lateral inhibitory processes-and enlarges as much as 10,000-fold during development. The resulting two-dimensional array is a fractal-like colour/size hierarchy lying in several layers of a multilayered network. Dynamic control of the array by muscles and nerves produces patterns that recall 'half-tone' processing (cf. ink-jet printer). In the more sophisticated (loliginid) squids, patterns also combine 'continuous tones' (cf. dye-sublimation printer). Physiologists and engineers can exploit the natural colour-coding of the integument to understand nerve and muscle system dynamics, examined here at the level of the ensemble. Integrative functions of the whole (H) are analysed in terms of the power spectrum within and between ensembles and of spontaneous waves travelling through the billboard. Video material may be obtained from the author at the above address.

  20. A SQUID Bootstrap Circuit with a Large Parameter Tolerance

    International Nuclear Information System (INIS)

    Zhang Guo-Feng; Kong Xiang-Yan; Xie Xiao-Ming; Zhang Yi; Krause Hans-Joachim; Offenhäusser Andreas

    2013-01-01

    The voltage biased (SQUID) bootstrap circuit (SBC) was recently introduced as an effective means to reduce the preamplifier noise contribution. We analyze the tolerances of the SBC noise suppression performance to spreads in SQUID and SBC circuit parameters. It is found that the tolerance to spread mainly caused by the integrated circuit fabrication process could be extended by a one-time adjustable current feedback. A helium-cooled niobium SQUID with a loop inductance of 350 pH is employed to experimentally verify the analysis. From this work, design criteria for fully integrated SBC devices with a high yield can be derived

  1. SQUIDs in thermal detectors of weakly interacting particles

    International Nuclear Information System (INIS)

    Trofimov, V.N.

    1991-01-01

    The application of four different types of SQUID-assisted thermometers for cryogenic thermal detectors of weakly interacting particles is analyzed with two of them for the first time. The classic resistive thermometer is considered as well for the comparison. Original results of testing the detector with working temperature of 1K and thermocouple thermometer with SQUID are given. The conclusion is made that temperature resolution of 10 -10 kHz -1/2 or energy sensitivity of 1-10 eV per 1 kg of detector mass can be achieved when using the SQUID-assisted thermometers. 12 refs.; 7 figs.; 1 tab

  2. rf SQUID system as tunable flux qubit

    Energy Technology Data Exchange (ETDEWEB)

    Ruggiero, B. [Istituto di Cibernetica ' E. Caianiello' del Consiglio Nazionale delle Ricerche, I-80078 Pozzuoli (Italy)]. E-mail: b.ruggiero@cib.na.cnr.it; Granata, C. [Istituto di Cibernetica ' E. Caianiello' del Consiglio Nazionale delle Ricerche, I-80078 Pozzuoli (Italy); Vettoliere, A. [Istituto di Cibernetica ' E. Caianiello' del Consiglio Nazionale delle Ricerche, I-80078 Pozzuoli (Italy); Rombetto, S. [Istituto di Cibernetica ' E. Caianiello' del Consiglio Nazionale delle Ricerche, I-80078 Pozzuoli (Italy); Russo, R. [Istituto di Cibernetica ' E. Caianiello' del Consiglio Nazionale delle Ricerche, I-80078 Pozzuoli (Italy); Russo, M. [Istituto di Cibernetica ' E. Caianiello' del Consiglio Nazionale delle Ricerche, I-80078 Pozzuoli (Italy); Corato, V. [Dipartimento di Ingegneria dell' Informazione, Seconda Universita di Napoli, I-81031 Aversa (Italy); Istituto di Cibernetica ' E. Caianiello' del Consiglio Nazionale delle Ricerche, I-80078 Pozzuoli (Italy); Silvestrini, P. [Dipartimento di Ingegneria dell' Informazione, Seconda Universita di Napoli, I-81031 Aversa (Italy); Istituto di Cibernetica ' E. Caianiello' del Consiglio Nazionale delle Ricerche, I-80078 Pozzuoli (Italy)

    2006-08-21

    We present a fully integrated rf SQUID-based system as flux qubit with a high control of the flux transfer function of the superconducting transformer modulating the coupling between the flux qubit and the readout system. The control of the system is possible by including into the superconducting flux transformer a vertical two-Josephson-junctions interferometer (VJI) in which the Josephson current is precisely modulated from a maximum to zero by a transversal magnetic field parallel to the flux transformer plane. The proposed system can be also used in a more general configuration to control the off-diagonal terms in the Hamiltonian of the flux qubit and to turn on and off the coupling between two or more qubits.

  3. Can understanding squid life-history strategies and recruitment ...

    African Journals Online (AJOL)

    Can understanding squid life-history strategies and recruitment improve management? ... range of potentially limiting conditions in different years, they store genetic diversity and stabilize recruitment in time. ... AJOL African Journals Online.

  4. Negative inductance SQUID qubit operating in a quantum regime

    Science.gov (United States)

    Liu, W. Y.; Su, F. F.; Xu, H. K.; Li, Z. Y.; Tian, Ye; Zhu, X. B.; Lu, Li; Han, Siyuan; Zhao, S. P.

    2018-04-01

    Two-junction SQUIDs with negative mutual inductance between their two arms, called nSQUIDs, have been proposed for significantly improving quantum information transfer but their quantum nature has not been experimentally demonstrated. We have designed, fabricated, and characterized superconducting nSQUID qubits. Our results provide clear evidence of the quantum coherence of the device, whose properties are well described by theoretical calculations using parameters determined from spectroscopic measurement. In addition to their future application for fast quantum information transfer, the nSQUID qubits exhibit rich characteristics in their tunable two-dimensional (2D) potentials, energy levels, wave function symmetries, and dipole matrix elements, which are essential to the study of a wide variety of macroscopic quantum phenomena such as tunneling in 2D potential landscapes.

  5. Reactive probing of macroscopically quantum mechanical SQUID rings

    International Nuclear Information System (INIS)

    Prance, R.J.; Clark, T.D.; Whiteman, R.; Diggins, J.; Ralph, J.F.; Prance, H.; Spiller, T.P.; Widom, A.; Srivastava, Y.

    1994-01-01

    In this paper we demonstrate that the energy level structure of ultra small capacitance SQUID rings can be probed adiabatically at radio frequency using both dynamical and quasistatic reactive techniques. ((orig.))

  6. Gear Selectivity of a Longfin Squid Bottom Trawl

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Loligo pealeii (longfin inshore squid) co-occurs with Atlantic butterfish (Peprilus triacanthus) throughout the year and discarding in the L. pealeii bottom trawl...

  7. Forecasting chokka squid Loligo vulgaris reynaudii catches and ...

    African Journals Online (AJOL)

    spamer

    2017-11-11

    Nov 11, 2017 ... on ambient water temperature (Augustyn et al. 1992,. A. Oosthuisen, University of ..... from tagged squid and the supply of continuous environ- mental data. ... should a leak develop, and to provide insulation for the electronics.

  8. Dc-SQUID sensor system for multichannel neuromagnetometry

    Energy Technology Data Exchange (ETDEWEB)

    Houwman, E.P.; Veldhuis, D.; Flokstra, ter Brake, H.J.M.; Jaszczuk, W.; Rogalla, H. (Univ. of Twente, Faculty of Applied Physics, P.O. Box 217, 7500 AE Enschede (NL)); Martinez, A. (Universidad de Zaragoza, E.T.S.I.I. Maria Zambrano 50, 50015 Zaragoza (ES))

    1991-03-01

    This paper reports on various DC-SQUID sensor configurations developed for use in the authors' 19-channel neuromagetometer. Apart from the standard type, resistively and indictively shunted SQUIDs were made, allowing for a large screening factor {beta} ({gt}1). In this way signal coupling from the pick-up coil to the SQUID is facilitated and capactive coupling between the input coil and the SQUID washer can be decreased. The number of turns of the input coil is decreased further by allowing for an inductance mismatch in the input circuit. Although theoretically both measures give rise to an increased field noise of the sensor, they may lead to a reduction of the excess noise and the noise balance may become positive.

  9. Symposium on applications of superconducting quantum interference devices (SQUIDS)

    International Nuclear Information System (INIS)

    1978-01-01

    The abstracts are given of thirteen papers presented at a ''SQUID Symposium'' organized by the Division of Materials Sciences of the U.S. Department of Energy and held March 23--25, 1978, at the University of Virginia. Since SQUID systems have already been utilized in feasibility demonstration in geothermal reservoir exploration, it was recognized that these devices also hold great potential for many other important scientific measurements. Many of these are energy-related, and others include forefront investigations in a diverse group of scientific areas, from biomedical to earthquake monitoring. Research in SQUIDs has advanced so rapidly in recent years that it was felt that a symposium to review the current status and future prospects of the devices would be timely. The abstracts given present an overview of work in this area and hopefully provide an opportunity to increase awareness among basic and applied scientists of the inherent implications of the extreme measurement sensitivity in advanced SQUID systems

  10. Nondestructive evaluation of metallic structures using a SQUID magnetometer

    International Nuclear Information System (INIS)

    Weinstock, H.; Nisenoff, M.

    1985-01-01

    We present one of the first reports of the use of SQUID instrumentation for nondestructive evaluation of electrically conducting and ferromagnetic specimens. We report preliminary experiments on the use of SQUIDs for the detection of defects (such as cracks, holes, weld seams, variations in wall thickness, effects of corrosion, etc.) in the walls of a hollow pipe, and for monitoring the magnetic state of a ferromagnetic sample under stress-strain loading conditions. (orig./BUD)

  11. High-performance DC SQUIDs with submicrometer niobium Josephson junctions

    Energy Technology Data Exchange (ETDEWEB)

    de Waal, V.J.; Klapwijk, T.M.; van den Hamer, P.

    1983-11-01

    We report on the fabrication and performance of low-noise, all-niobium, thin-film planar dc SQUIDs with submicrometer Josephson junctions. The junctions are evaporated obliquely through a metal shadow evaporation mask, which is made using optical lithography with 0.5 ..mu..m tolerance. The Josephson junction barrier is formed by evaporating a thin silicon film and with a subsequent oxidation in a glow discharge. The junction parameters can be reproduced within a factor of two. Typical critical currents of the SQUIDs are about 3 ..mu..A and the resistances are about 100 ..cap omega... With SQUIDs having an inductance of 1 nH the voltage modulation is a least 60 ..mu..V. An intrinsic energy resolution of 4 x 10/sup -32/ J/Hz has been reached. The SQUIDs are coupled to wire-wound input coils or with thin-film input coils. The thin-film input coil consists of a niobium spiral of 20 turns on a separate substrate. In both cases the coil is glued onto a 2-nH SQUID with a coupling efficiency of at least 0.5. Referred to the thin-film input coil, the best coupled energy resolution achieved is 1.2 x 10/sup -30/ J/Hz measured in a flux-locked loop at frequencies above 10 Hz. As far as we know, this is the best figure achieved with an all-refractory-metal thin-film SQUID. The fabrication technique used is suited for making circuits with SQUID and pickup coil on the same substrate. We describe a compact, planar, first-order gradiometer integrated with a SQUID on a single substrate. The gradient noise of this device is 3 x 10/sup -12/ Tm/sup -1/. The gradiometer has a size of 12 mm x 17 mm, is simple to fabricate, an is suitable for biomedical applications.

  12. High-performance dc SQUIDs with submicrometer niobium Josephson junctions

    Science.gov (United States)

    de Waal, V. J.; Klapwijk, T. M.; van den Hamer, P.

    1983-11-01

    We report on the fabrication and performance of low-noise, all-niobium, thin-film planar dc SQUIDs with submicrometer Josephson junctions. The junctions are evaporated obliquely through a metal shadow evaporation mask, which is made using optical lithography with 0.5 µm tolerance. The Josephson junction barrier is formed by evaporating a thin silicon film and with a subsequent oxidation in a glow discharge. The junction parameters can be reproduced within a factor of two. Typical critical currents of the SQUIDs are about 3 µA and the resistances are about 100 Ω. With SQUIDs having an inductance of 1 nH the voltage modulation is at least 60 µV. An intrinsic energy resolution of 4×10-32 J/Hz has been reached. The SQUIDs are coupled to wire-wound input coils or with thin-film input coils. The thin-film input coil consists of a niobium spiral of 20 turns on a separate substrate. In both cases the coil is glued onto a 2-nH SQUID with a coupling efficiency of at least 0.5. Referred to the thin-film input coil, the best coupled energy resolution achieved is 1.2×10-30 J/Hz measured in a flux-locked loop at frequencies above 10 Hz. As far as we know, this is the best figure achieved with an all-refractory-metal thin-film SQUID. The fabrication technique used is suited for making circuits with SQUID and pickup coil on the same substrate. We describe a compact, planar, first-order gradiometer integrated with a SQUID on a single substrate. The gradient noise of this device is 3×10-12 T m-1. The gradiometer has a size of 12 mm×17 mm, is simple to fabricate, and is suitable for biomedical applications.

  13. High transition-temperature SQUID magnetometers and practical applications

    International Nuclear Information System (INIS)

    Dantsker, E.; Lawrence Berkeley National Lab., CA

    1997-05-01

    The design, fabrication and performance of SQUID magnetometers based on thin films of the high-transition temperature superconductor YBa 2 Cu 3 O 7-x (YBCO) are described. Essential to the achieving high magnetic field resolution at low frequencies is the elimination of 1/f flux noise due to thermally activated hopping of flux vortices between pinning sites in the superconducting films. Through improvements in processing, 1/f noise in single layer YBCO thin films and YBCO-SrTiO 3 -YBCO trilayers was systematically reduced to allow fabrication of sensitive SQUID magnetometers. Both single-layer directly coupled SQUID magnetometers and multilayer magnetometers were fabricated, based on the dc SQUID with bicrystal grain boundary Josephson junctions. Multilayer magnetometers had a lower magnetic field noise for a given physical size due to greater effective sensing areas. A magnetometer consisting of a SQUID inductively coupled to the multiturn input coil of a flux transformer in a flip-chip arrangement had a field noise of 27 fT Hz -1/2 at 1 Hz and 8.5 fT Hz -1/2 at 1 kHz. A multiloop multilayer SQUID magnetometer had a field noise of 37 fT Hz -1/2 at 1 Hz and 18 fT Hz -1/2 at 1 kHz. A three-axis SQUID magnetometer for geophysical applications was constructed and operated in the field in the presence of 60 Hz and radiofrequency noise. Clinical quality magnetocardiograms were measured using multilayer SQUID magnetometers in a magnetically shielded room

  14. High transition-temperature SQUID magnetometers and practical applications

    Energy Technology Data Exchange (ETDEWEB)

    Dantsker, Eugene [Univ. of California, Berkeley, CA (United States). Dept. of Physics

    1997-05-01

    The design, fabrication and performance of SQUID magnetometers based on thin films of the high-transition temperature superconductor YBa2Cu3O7-x (YBCO) are described. Essential to the achieving high magnetic field resolution at low frequencies is the elimination of 1/f flux noise due to thermally activated hopping of flux vortices between pinning sites in the superconducting films. Through improvements in processing, 1/f noise in single layer YBCO thin films and YBCO-SrTiO3-YBCO trilayers was systematically reduced to allow fabrication of sensitive SQUID magnetometers. Both single-layer directly coupled SQUID magnetometers and multilayer magnetometers were fabricated, based on the dc SQUID with bicrystal grain boundary Josephson junctions. Multilayer magnetometers had a lower magnetic field noise for a given physical size due to greater effective sensing areas. A magnetometer consisting of a SQUID inductively coupled to the multiturn input coil of a flux transformer in a flip-chip arrangement had a field noise of 27 fT Hz-1/2 at 1 Hz and 8.5 fT Hz-1/2 at 1 kHz. A multiloop multilayer SQUID magnetometer had a field noise of 37 fT Hz-1/2 at 1 Hz and 18 fT Hz-1/2 at 1 kHz. A three-axis SQUID magnetometer for geophysical applications was constructed and operated in the field in the presence of 60 Hz and radiofrequency noise. Clinical quality magnetocardiograms were measured using multilayer SQUID magnetometers in a magnetically shielded room.

  15. Characterization of thermal aging of duplex stainless steel by SQUID

    International Nuclear Information System (INIS)

    Isobe, Y.; Kamimura, A.; Aoki, K.; Nakayasu, F.

    1995-01-01

    Thermal aging is a growing concern for long-term-aged duplex stainless steel piping in nuclear power plants. Superconducting QUantum Interference Device (SQUID) was used for the detection of thermal aging of SUS329 rolled duplex stainless steel and SCS16 cast duplex stainless steel. It was found that the SQUID output signal pattern in the presence of AC magnetic field applied to the specimen was sensitive to the changes in electromagnetic properties due to thermal aging

  16. Nb nanoSQUIDs for detection of small spin systems

    Energy Technology Data Exchange (ETDEWEB)

    Woelbing, R.; Nagel, J.; Kemmler, M.; Kleiner, R.; Koelle, D. [Physikalisches Institut, Universitaet Tuebingen (Germany); Kieler, O.; Weimann, T.; Kohlmann, J.; Zorin, A. [Fachbereich 2.4 ' ' Quantenelektronik' ' , PTB Braunschweig (Germany); Buchter, A.; Xue, F.; Poggio, M. [Department of Physics, University of Basel (Switzerland); Rueffer, D.; Russo-Averchi, E.; Fontcuberta i Morral, A. [Laboratoire des Materiaux Semiconducteurs, EPF Lausanne (Switzerland); Huber, R.; Berberich, P. [Physik-Department E10, Technische Universitaet Muenchen (Germany); Grundler, D. [Laboratoire des Materiaux Semiconducteurs, EPF Lausanne (Switzerland); Physik-Department E10, Technische Universitaet Muenchen (Germany)

    2013-07-01

    We report on the realization of highly sensitive dc nanoSQUIDs for the investigation of small spin systems in moderate magnetic fields. The Nb SQUIDs are based on normal metal Josephson junctions made of HfTi and patterned by e-beam lithography. We demonstrate stable operation up to B = ± 50 mT without degradation of rms flux noise (S{sub Φ}{sup 1/2} ≤ 280 nΦ{sub 0}/√(Hz)). We also present a multifunctional system combining a Nb nanoSQUID and a low-temperature magnetic force microscope (LTMFM) with a Ni nanotube as a scanning tip. This system allows for magnetization measurements of the Ni tube by using both, LTMFM and SQUID readout. Furthermore, the measurement of magnetic flux Φ vs. position of the particle provides an experimental determination of the coupling factor φ{sub μ} = Φ/μ between SQUID and Ni tube with magnetic moment μ. The results confirm our predictions from numerical simulations, taking into account the SQUID geometry.

  17. Algebraic approach to time-delay data analysis for LISA

    International Nuclear Information System (INIS)

    Dhurandhar, S.V.; Nayak, K. Rajesh; Vinet, J.-Y.

    2002-01-01

    Cancellation of laser frequency noise in interferometers is crucial for attaining the requisite sensitivity of the triangular three-spacecraft LISA configuration. Raw laser noise is several orders of magnitude above the other noises and thus it is essential to bring it down to the level of other noises such as shot, acceleration, etc. Since it is impossible to maintain equal distances between spacecrafts, laser noise cancellation must be achieved by appropriately combining the six beams with appropriate time delays. It has been shown in several recent papers that such combinations are possible. In this paper, we present a rigorous and systematic formalism based on algebraic geometrical methods involving computational commutative algebra, which generates in principle all the data combinations canceling the laser frequency noise. The relevant data combinations form the first module of syzygies, as it is called in the literature of algebraic geometry. The module is over a polynomial ring in three variables, the three variables corresponding to the three time delays around the LISA triangle. Specifically, we list several sets of generators for the module whose linear combinations with polynomial coefficients generate the entire module. We find that this formalism can also be extended in a straightforward way to cancel Doppler shifts due to optical bench motions. The two modules are in fact isomorphic. We use our formalism to obtain the transfer functions for the six beams and for the generators. We specifically investigate monochromatic gravitational wave sources in the LISA band and carry out the maximization over linear combinations of the generators of the signal-to-noise ratios with the frequency and source direction angles as parameters

  18. GCR flux 9-day variations with LISA Pathfinder

    International Nuclear Information System (INIS)

    Grimani, C; Benella, S; Fabi, M; Finetti, N; Telloni, D

    2017-01-01

    Galactic cosmic-ray (GCR) energy spectra in the heliosphere vary on the basis of the level of solar activity, the status of solar polarity and interplanetary transient magnetic structures of solar origin. A high counting rate particle detector (PD) aboard LISA Pathfinder (LPF) allows for the measurement of galactic cosmic-ray and solar energetic particle (SEP) integral fluxes at energies > 70 MeV n −1 up to 6500 counts s −1 . Data are gathered with a sampling time of 15 s. A study of GCR flux depressions associated with the third harmonic of the Sun rotation period (∼ 9 days) is presented here. (paper)

  19. Energy transport in mirror machine LISA at electron cyclotron resonance

    International Nuclear Information System (INIS)

    Cunha Rapozo, C. da; Serbeto, A.; Torres-Silva, H.

    1993-01-01

    It is shown that a classical transport calculation is adequate to predict the steady state temperature of the RF produced plasma in LISA machine for both large and small resonant volumes. Temperature anisotropy ranging from 55 to 305 was found which was larger for small resonant volume, and the temperature relaxation was larger at large resonant one. This agrees with the fact that there is a Coulomb relaxation ν c which is proportional to T e -3/2 . It is also shown that the fitting parameter alpha is larger for large resonant volume than for small resonant one. (L.C.J.A.)

  20. A study on the radionuclide migration by means of the code LISA

    International Nuclear Information System (INIS)

    Frenquellucci, F.; Deserti, M.

    1989-01-01

    LISA code (Long Term Isolation Safety Assessment) has been developed by J.R.C. EUROATOM Ispra (Radiochemistry Division) and it's utilized in order to study migration of radionuclides through porous media. Aim of the present work is to analyze LISA's input and output files. A brief description of the code is also performed. As LISA is a research and in development code, its structure is rather complex and an exhaustive description of input/output files is helpful for the user. Version 3 of LISA code, loaded on ENEA's IBM 3090, is avaylable by ENEA-VEL Bologna

  1. Prospects of eLISA for Detecting Galactic Binary Black Holes Similar to GW150914

    OpenAIRE

    Seto, Naoki

    2016-01-01

    We discuss the prospects of eLISA for detecting gravitational waves (GWs) from Galactic binary black holes (BBHs) similar to GW150914. For a comoving merger rate that is consistent with current observation, eLISA is likely to identify at least one BBH with a sufficient signal-to-noise ratio. In addition, eLISA has a potential to measure the eccentricity of the BBH as small as $e\\sim 0.02$, corresponding to the residual value $e\\sim 10^{-6}$ at 10Hz. Therefore, eLISA could provide us with a cr...

  2. The low fault HTSL-SQUID cooling system. Final report; Stoerarmes HTSL-SQUID-Kuehlsystem. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Binneberg, A.; Spoerl, G.; Buschmann, H.

    1997-03-01

    In the context of the research project, work was done for HTSL-SQUID on (1) the development of a thermo-siphon cooler (low fault and continuously working) and (2) the development of a latent storage cooler (low fault and discontinuously working). Two development versions of the latent storage cooler were followed up, the development of a spherical latent storage cooler and the development of an annular vessel latent storage cooler. A further precondition for the construction of the cooler was the use of split Stirling refrigerators as units producing the cold. The experimental sample was built up with refrigerators which could produce a nominal cooling output of 1.2 W at 80 K. Two samples of the thermo-siphon cooler were built, tested and improved. The second sample was developed further as a demonstration model, introduced at meetings and prepared for testing the cooling of HTSL-SQUIDs. The thermo-siphon cooler can be designed for cooling output up to about 2 W at 80 K and can be used controlled for a temperature range of 90 K to 66 K. (orig./MM) [Deutsch] Im Rahmen des Forschungsvorhabens wurde fuer HTSL-SQUID`s an der (1) Entwicklung eines Thermosiphon-Kuehlers (stoerarm und kontinuierlich arbeitend) und (2) Entwicklung eines Latentspeicher-Kuehlers (stoerfrei und diskontinuierlich arbeitend) gearbeitet. Bei dem Latentspeicher-Kuehler wurden zwei Entwicklungsversionen verfolgt, und zwar Entwicklung eines Kugel-Latentspeicher-Kuehlers und Entwicklung eines Ringgefaess-Latentspeicher-Kuehlers. Eine weitere Praemisse zum Aufbau der Kuehler war der Einsatz von Split-Stirling-Kaeltemaschinen als kaelteerzeugende Baugruppe. Die Versuchsmuster wurden mit Kaeltemaschinen aufgebaut, die eine Nennkuehlleistung von 1,2 W bei 80 K erzeugen konnten. Der Thermosiphon-Kuehler wurde in zwei Musterexemplaren aufgebaut, erprobt und verbessert. Das Zweitmuster wurde als Demonstrator weiterentwickelt, zu Fachtagungen vorgestellt und zur Testung der Kuehlung von HTSL-SQUIDs

  3. The magnetic diagnostics subsystem of the LISA Technology Package

    Energy Technology Data Exchange (ETDEWEB)

    Diaz-Aguilo, M; Garcia-Berro, E [Departament de Fisica Aplicada, Universitat Politecnica de Catalunya, c/Esteve Terrades, 5, 08860 Castelldefels (Spain); Lobo, A; Mateos, N; Sanjuan, J, E-mail: marc.diaz.aguilo@fa.upc.ed [Institut d' Estudis Espacials de Catalunya, c/Gran Capita 2-4, Edif. Nexus 104, 08034 Barcelona (Spain)

    2010-05-01

    The Magnetic Diagnostics Subsystem of the LISA Technology Package (LTP) on board the LISA Pathfinder (LPF) spacecraft includes a set of four tri-axial fluxgate magnetometers, intended to measure with high precision the magnetic field at the positions they occupy. However, their readouts do not provide a direct measurement of the magnetic field at the positions of the test masses. Therefore, an interpolation method must be implemented to obtain this information. However, such interpolation process faces serious difficulties. Indeed, the size of the interpolation region is excessive for a linear interpolation to be reliable, and the number of magnetometer channels does not provide sufficient data to go beyond that poor approximation. Recent research points to a possible alternative to address the magnetic interpolation problem by means of neural network algorithms. The key point of this approach is the ability neural networks have to learn from suitable training data representing the magnetic field behaviour. Despite the large distance to the test masses and the insufficient magnetic readings, artificial neural networks are able to significantly reduce the estimation error to acceptable levels. The learning efficiency can be best improved by making use of data obtained from on-ground measurements prior to mission launch in all relevant satellite locations and under real operation conditions. Reliable information on that appears to be essential for a meaningful assessment of magnetic noise in the LTP.

  4. The magnetic diagnostics subsystem of the LISA Technology Package

    International Nuclear Information System (INIS)

    Diaz-Aguilo, M; Garcia-Berro, E; Lobo, A; Mateos, N; Sanjuan, J

    2010-01-01

    The Magnetic Diagnostics Subsystem of the LISA Technology Package (LTP) on board the LISA Pathfinder (LPF) spacecraft includes a set of four tri-axial fluxgate magnetometers, intended to measure with high precision the magnetic field at the positions they occupy. However, their readouts do not provide a direct measurement of the magnetic field at the positions of the test masses. Therefore, an interpolation method must be implemented to obtain this information. However, such interpolation process faces serious difficulties. Indeed, the size of the interpolation region is excessive for a linear interpolation to be reliable, and the number of magnetometer channels does not provide sufficient data to go beyond that poor approximation. Recent research points to a possible alternative to address the magnetic interpolation problem by means of neural network algorithms. The key point of this approach is the ability neural networks have to learn from suitable training data representing the magnetic field behaviour. Despite the large distance to the test masses and the insufficient magnetic readings, artificial neural networks are able to significantly reduce the estimation error to acceptable levels. The learning efficiency can be best improved by making use of data obtained from on-ground measurements prior to mission launch in all relevant satellite locations and under real operation conditions. Reliable information on that appears to be essential for a meaningful assessment of magnetic noise in the LTP.

  5. Classifying LISA gravitational wave burst signals using Bayesian evidence

    International Nuclear Information System (INIS)

    Feroz, Farhan; Graff, Philip; Hobson, Michael P; Lasenby, Anthony; Gair, Jonathan R

    2010-01-01

    We consider the problem of characterization of burst sources detected by the Laser Interferometer Space Antenna (LISA) using the multi-modal nested sampling algorithm, MultiNest. We use MultiNest as a tool to search for modelled bursts from cosmic string cusps, and compute the Bayesian evidence associated with the cosmic string model. As an alternative burst model, we consider sine-Gaussian burst signals, and show how the evidence ratio can be used to choose between these two alternatives. We present results from an application of MultiNest to the last round of the Mock LISA Data Challenge, in which we were able to successfully detect and characterize all three of the cosmic string burst sources present in the release data set. We also present results of independent trials and show that MultiNest can detect cosmic string signals with signal-to-noise ratio (SNR) as low as ∼7 and sine-Gaussian signals with SNR as low as ∼8. In both cases, we show that the threshold at which the sources become detectable coincides with the SNR at which the evidence ratio begins to favour the correct model over the alternative.

  6. Disentangling the magnetic force noise contribution in LISA Pathfinder

    International Nuclear Information System (INIS)

    Armano, M; Audley, H; Born, M; Danzmann, K; Diepholz, I; Auger, G; Binetruy, P; Baird, J; Bortoluzzi, D; Brandt, N; Fitzsimons, E; Bursi, A; Caleno, M; Cavalleri, A; Cesarini, A; Dolesi, R; Ferroni, V; Cruise, M; Dunbar, N; Ferraioli, L

    2015-01-01

    Magnetically-induced forces on the inertial masses on-board LISA Pathfinder are expected to be one of the dominant contributions to the mission noise budget, accounting for up to 40%. The origin of this disturbance is the coupling of the residual magnetization and susceptibility of the test masses with the environmental magnetic field. In order to fully understand this important part of the noise model, a set of coils and magnetometers are integrated as a part of the diagnostics subsystem. During operations a sequence of magnetic excitations will be applied to precisely determine the coupling of the magnetic environment to the test mass displacement using the on-board magnetometers. Since no direct measurement of the magnetic field in the test mass position will be available, an extrapolation of the magnetic measurements to the test mass position will be carried out as a part of the data analysis activities. In this paper we show the first results on the magnetic experiments during an end- to-end LISA Pathfinder simulation, and we describe the methods under development to map the magnetic field on-board. (paper)

  7. Revised electrostatic model of the LISA Pathfinder inertial sensor

    Energy Technology Data Exchange (ETDEWEB)

    Brandt, Nico [Astrium GmbH, 88039 Friedrichshafen (Germany); Fichter, Walter, E-mail: nico.brandt@astrium.eads.ne [iFR, Universitaet Stuttgart, Pfaffenwaldring 7a, 70569 Stuttgart (Germany)

    2009-03-01

    A comprehensive electrostatic finite-element (FE) analysis of the LISA Pathfinder Inertial Sensor (IS) has been carried out at Astrium GmbH. Starting with a detailed geometrical model of the IS housing and test mass (TM) flight units, FE results were derived from multiple analyses runs applying the Maxwell 3D field simulation software. The electrostatic forces and torques on the TM in 6DoF, as well as all non-negligible capacitances between the TM, the 18 electrodes, and the housing, have been extracted for different TM translations and rotations. The results of the FE analyses were expected to confirm the existing IS electrostatic model predictions used for performance analysis, simulations, and on-board algorithms. Major discrepancies were found, however, between the results and the model used so far. In general, FE results give considerably larger capacitance values than the equivalent infinite non-parallel plate estimates. In contrast, the FE derived forces and torques are in general significantly lower compared to the analytic IS electrostatic model predictions. In this paper, these results are discussed in detail and the reasons for the deviations are elaborated. Based on these results, an adapted analytic IS electrostatic model is proposed that reflects the electrostatic forces, torques, and stiffness values in the LISA Pathfinder IS significantly more accurate.

  8. Revised electrostatic model of the LISA Pathfinder inertial sensor

    International Nuclear Information System (INIS)

    Brandt, Nico; Fichter, Walter

    2009-01-01

    A comprehensive electrostatic finite-element (FE) analysis of the LISA Pathfinder Inertial Sensor (IS) has been carried out at Astrium GmbH. Starting with a detailed geometrical model of the IS housing and test mass (TM) flight units, FE results were derived from multiple analyses runs applying the Maxwell 3D field simulation software. The electrostatic forces and torques on the TM in 6DoF, as well as all non-negligible capacitances between the TM, the 18 electrodes, and the housing, have been extracted for different TM translations and rotations. The results of the FE analyses were expected to confirm the existing IS electrostatic model predictions used for performance analysis, simulations, and on-board algorithms. Major discrepancies were found, however, between the results and the model used so far. In general, FE results give considerably larger capacitance values than the equivalent infinite non-parallel plate estimates. In contrast, the FE derived forces and torques are in general significantly lower compared to the analytic IS electrostatic model predictions. In this paper, these results are discussed in detail and the reasons for the deviations are elaborated. Based on these results, an adapted analytic IS electrostatic model is proposed that reflects the electrostatic forces, torques, and stiffness values in the LISA Pathfinder IS significantly more accurate.

  9. T.D Lee and Lisa Randall visit ATLAS

    CERN Multimedia

    Pauline Gagnon

    Professor Tsung-Dao Lee, who received the Nobel Prize for Physics in 1957 for postulating that parity is not conserved in weak interactions, visited the ATLAS detector this month. He is seen here in the company of Peter Jenni, spokesperson for ATLAS. T.D. Lee is still very active at over 80, pursuing his theory work to this day. Professor Lisa Randall from Harvard University, the well-known theorist behind the Randall-Sundrum theory for extra dimensions, was also part of the group visiting the ATLAS detector. She is seen here with Fabiola Gianotti, deputy spokesperson for ATLAS. Lisa Randall's two initial papers have been quoted both more than 2500 times, making her the most cited theoretical physicist in the world in the last five years as of last autumn - a total of about 10,000 citations! One wonders here if Peter is pointing to a CP-violating graviton spotted in the ATLAS cavern... From left to right: Fabiola Gianotti, Gustaaf Brooijmans, convener of the ATLAS Exotics physics gro...

  10. Measurements of the dynamic input impedance of a dc SQUID

    International Nuclear Information System (INIS)

    Hilbert, C.; Clarke, J.

    1985-01-01

    The impedance of a circuit coupled magnetically via a mutual inductance M/sub i/ to a dc SQUID of geometric inductance L is modified by the dynamic input impedance of the SQUID, which can be characterized by the flux-to-current transfer function J/sub Phi/approx. =partialJ/partialPhi; J is the current circulating in the SQUID loop and ∫ is the flux applied to the loop. At the same time, the SQUID is modified by the presence of the input circuit in the lumped circuit approximation, one expects its inductance to be reduced to L'(1-α/sub e/ 2 )L, where α/sub e/ is an effective coupling coefficient. Calculations of J/sub Phi/ using an analog simulator are described and presented in the form of a dynamic inductance L and a dynamic resistance R versus bias current I and Phi. Experimental measurements of L and R were made on a planar, thin-film SQUID tightly coupled to a spiral input coil that was connected in series with a capacitor C/sub i/ to form a resonant circuit. Thus, J/sub Phi/ was determined from the change in the resonant frequency and quality factor of this circuit as a function of I and Phi. At low bias currents (low Josephson frequencies) the measured values of L were in reasonable agreement with values simulated for the reduced SQUID, while at higher bias currents (higher Josephson frequencies) the measured values were in better agreement with values simulated for the unscreened SQUID. Similar conclusions were reached in the comparison of the experimental and simulated values of the flux-to-voltage transfer function V/sub Phi/

  11. Nuclear magnetic resonance experiments with dc SQUID amplifiers

    International Nuclear Information System (INIS)

    Heaney, M.B.

    1990-11-01

    The development and fabrication of dc SQUIDs (Superconducting QUantum Interference Devices) with Nb/Al 2 O 3 /Nb Josephson junctions is described. A theory of the dc SQUID as a radio-frequency amplifier is presented, with an optimization strategy that accounts for the loading and noise contributions of the postamplifier and maximizes the signal-to-noise ratio of the total system. The high sensitivity of the dc SQUID is extended to high field NMR. A dc SQUID is used as a tuned radio-frequency amplifier to detect pulsed nuclear magnetic resonance at 32 MHz from a metal film in a 3.5 Tesla static field. A total system noise temperature of 11 K has been achieved, at a bath temperature of 4.2 K. The minimum number of nuclear Bohr magnetons observable from a free precession signal after a single pulse is about 2 x 10 17 in a bandwidth of 25 kHz. In a separate experiment, a dc SQUID is used as a rf amplifier in a NQR experiment to observe a new resonance response mechanism. The net electric polarization of a NaClO 3 crystal due to the precessing electric quadrupole moments of the Cl nuclei is detected at 30 MHz. The sensitivity of NMR and NQR spectrometers using dc SQUID amplifiers is compared to the sensitivity of spectrometers using conventional rf amplifiers. A SQUID-based spectrometer has a voltage sensitivity which is comparable to the best achieved by a FET-based spectrometer, at these temperatures and operating frequencies

  12. SQUID use for Geophysics: finding billions of dollars

    Science.gov (United States)

    Foley, Catherine

    2014-03-01

    Soon after their discovery, Jim Zimmerman saw the potential of using Superconducting Quantum Interference Devices, SQUIDs, for the study of Geophysics and undertook experiments to understand the magnetic phenomena of the Earth. However his early experiments were not successful. Nevertheless up to the early 1980's, some research effort in the use of SQUIDs for geophysics continued and many ideas of how you could use SQUIDs evolved. Their use was not adopted by the mining industry at that time for a range of reasons. The discovery of high temperature superconductors started a reinvigoration in the interest to use SQUIDs for mineral exploration. Several groups around the world worked with mining companies to develop both liquid helium and nitrogen cooled systems. The realisation of the achievable sensitivity that contributed to successful mineral discoveries and delineation led to real financial returns for miners. By the mid 2000's, SQUID systems for geophysics were finally being offered for sale by several start-up companies. This talk will tell the story of SQUID use in geophysics. It will start with the early work of the SQUID pioneers including that of Jim Zimmerman and John Clarke and will also cover the development since the early 1990's up to today of a number of magnetometers and gradiometers that have been successfully commercialised and used to create significant impact in the global resources industry. The talk will also cover some of the critical technical challenges that had to be overcome to succeed. It will focus mostly on magnetically unshielded systems used in the field although some laboratory-based systems will be discussed.

  13. White-dwarf-white-dwarf galactic background in the LISA data

    International Nuclear Information System (INIS)

    Edlund, Jeffrey A.; Tinto, Massimo; Krolak, Andrzej; Nelemans, Gijs

    2005-01-01

    LISA (Laser Interferometer Space Antenna) is a proposed space mission, which will use coherent laser beams exchanged between three remote spacecraft to detect and study low-frequency cosmic gravitational radiation. In the low part of its frequency band, the LISA strain sensitivity will be dominated by the incoherent superposition of hundreds of millions of gravitational wave signals radiated by inspiraling white-dwarf binaries present in our own Galaxy. In order to estimate the magnitude of the LISA response to this background, we have simulated a synthesized population that recently appeared in the literature. Our approach relies on entirely analytic expressions of the LISA time-delay interferometric responses to the gravitational radiation emitted by such systems, which allows us to implement a computationally efficient and accurate simulation of the background in the LISA data. We find the amplitude of the galactic white-dwarf binary background in the LISA data to be modulated in time, reaching a minimum equal to about twice that of the LISA noise for a period of about two months around the time when the Sun-LISA direction is roughly oriented towards the Autumn equinox. This suggests that, during this time period, LISA could search for other gravitational wave signals incoming from directions that are away from the galactic plane. Since the galactic white-dwarf background will be observed by LISA not as a stationary but rather as a cyclostationary random process with a period of 1 yr, we summarize the theory of cyclostationary random processes, present the corresponding generalized spectral method needed to characterize such process, and make a comparison between our analytic results and those obtained by applying our method to the simulated data. We find that, by measuring the generalized spectral components of the white-dwarf background, LISA will be able to infer properties of the distribution of the white-dwarf binary systems present in our Galaxy

  14. High-Tc SQUIDs: Noise and applications

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Hsiao-Mei [Univ. of Houston, TX (United States)

    2001-08-01

    A major challenge in the design and operation of high transition temperature (Tc ) Superconducting Quantum Interference Devices (SQUIDs) is their potential to exhibit substantially higher levels of noise at low frequency f when exposed to earth’s magnetic field. To investigate this problem, we studied the noise of high-Tc SQUIDs, directly coupled magnetometers and multilayer magnetometers in both static and changing magnetic fields. The directly coupled magnetometer consists of a dc SQUID connected to a large area pickup loop in parallel. The multilayer magnetometer involves a multiturn flux transformer inductively coupled to a dc SQUID on a separate substrate. All the devices are made of thin films of the high-Tc superconductor YBa2Cu3O7-δ, patterned into 4 μm linewidths. After cooling in a magnetic field, the devices showed no increase in 1/f noise for fields up to threshold values well above the earth’s magnetic field. The devices were also cooled in a magnetic field that was subsequently turned off. The 1/f noise of bare SQUIDs was unchanged for fields up to 12 μT. The addition of the flux transformer containing flux dams increased the sensitivity to magnetic field by a factor of 43 while reducing the threshold field only moderately, to 5 μT. This result implies that the multilayer magnetometer can be rotated in the earth’s magnetic field through an angle of up to 26o without increasing the low frequency noise. The results of these studies were incorporated into a 5-channel high-Tc magnetocardiography system involving two first-derivative SQUID gradiometers and three reference SQUIDs. Each planar gradiometer consists of a directly coupled SQUID magnetometer inductively coupled to the smaller coil of an asymmetric, two-loop flux transformer. The reference SQUIDs are patterned into 4 μm lines. The outputs of the five channels were subtracted in software to form a second-derivative gradiometer. Its

  15. Beyond the Required LISA Free-Fall Performance: New LISA Pathfinder Results down to 20 μ Hz

    Science.gov (United States)

    Armano, M.; Audley, H.; Baird, J.; Binetruy, P.; Born, M.; Bortoluzzi, D.; Castelli, E.; Cavalleri, A.; Cesarini, A.; Cruise, A. M.; Danzmann, K.; de Deus Silva, M.; Diepholz, I.; Dixon, G.; Dolesi, R.; Ferraioli, L.; Ferroni, V.; Fitzsimons, E. D.; Freschi, M.; Gesa, L.; Gibert, F.; Giardini, D.; Giusteri, R.; Grimani, C.; Grzymisch, J.; Harrison, I.; Heinzel, G.; Hewitson, M.; Hollington, D.; Hoyland, D.; Hueller, M.; Inchauspé, H.; Jennrich, O.; Jetzer, P.; Karnesis, N.; Kaune, B.; Korsakova, N.; Killow, C. J.; Lobo, J. A.; Lloro, I.; Liu, L.; López-Zaragoza, J. P.; Maarschalkerweerd, R.; Mance, D.; Meshksar, N.; Martín, V.; Martin-Polo, L.; Martino, J.; Martin-Porqueras, F.; Mateos, I.; McNamara, P. W.; Mendes, J.; Mendes, L.; Nofrarias, M.; Paczkowski, S.; Perreur-Lloyd, M.; Petiteau, A.; Pivato, P.; Plagnol, E.; Ramos-Castro, J.; Reiche, J.; Robertson, D. I.; Rivas, F.; Russano, G.; Slutsky, J.; Sopuerta, C. F.; Sumner, T.; Texier, D.; Thorpe, J. I.; Vetrugno, D.; Vitale, S.; Wanner, G.; Ward, H.; Wass, P. J.; Weber, W. J.; Wissel, L.; Wittchen, A.; Zweifel, P.

    2018-02-01

    In the months since the publication of the first results, the noise performance of LISA Pathfinder has improved because of reduced Brownian noise due to the continued decrease in pressure around the test masses, from a better correction of noninertial effects, and from a better calibration of the electrostatic force actuation. In addition, the availability of numerous long noise measurement runs, during which no perturbation is purposely applied to the test masses, has allowed the measurement of noise with good statistics down to 20 μ Hz . The Letter presents the measured differential acceleration noise figure, which is at (1.74 ±0.01 ) fm s-2/√{Hz } above 2 mHz and (6 ±1 ) ×10 fm s-2/√{Hz } at 20 μ Hz , and discusses the physical sources for the measured noise. This performance provides an experimental benchmark demonstrating the ability to realize the low-frequency science potential of the LISA mission, recently selected by the European Space Agency.

  16. SQUIDs De-fluxing Using a Decaying AC Magnetic Field

    Energy Technology Data Exchange (ETDEWEB)

    Matlashov, Andrei Nikolaevich [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Semenov, Vasili Kirilovich [State Univ. of New York (SUNY), Plattsburgh, NY (United States); Anderson, Bill [Senior Scientific, LLC, Albuquerque, NM (United States)

    2016-06-08

    Flux trapping is the Achilles’ heel of all superconductor electronics. The most direct way to avoid flux trapping is a prevention of superconductor circuits from exposure to magnetic fields. Unfortunately this is not feasible if the circuits must be exposed to a strong DC magnetic field even for a short period of time. For example, such unavoidable exposures take place in superparamagnetic relaxation measurements (SPMR) and ultra-low field magnetic resonance imaging (ULF MRI) using unshielded thin-film SQUID-based gradiometers. Unshielded SQUIDs stop working after being exposed to DC magnetic fields of only a few Gauss in strength. In this paper we present experimental results with de-fluxing of planar thin-film LTS SQUID-based gradiometers using a strong decaying AC magnetic field. We used four commercial G136 gradiometers for SPMR measurements with up to a 10 mT magnetizing field. Strong 12.9 kHz decaying magnetic field pulses reliably return SQUIDs to normal operation 50 ms after zeroing the DC magnetizing field. This new AC de-fluxing method was also successfully tested with seven other different types of LTS SQUID sensors and has been shown to dissipate extremely low energy.

  17. Probing the Universe with Gravitational Waves: the Laser Interferometer Space Antenna (LISA)

    NARCIS (Netherlands)

    Prince, T.A.; Binetruy, P.; Centrella, J.; Finn, L.; Hogan, C.; Nelemans, G.A.; Phinney, S.

    2007-01-01

    - For the LISA International Science Team: LISA is a joint NASA/ESA space mission designed to measure gravitational waves in the band from 0.1 mHz to 0.1 Hz, a band that is richly populated by strong sources of gravitational waves. Signals will come from a wider range of sources: massive black holes

  18. Control system design for the constellation acquisition phase of the LISA mission

    Energy Technology Data Exchange (ETDEWEB)

    Cirillo, Francesca; Gath, Peter F, E-mail: francesca.cirillo@astrium.eads.ne, E-mail: peter.gath@astrium.eads.ne [Astrium GmbH Satellites, 88039 Friedrichshafen (Germany)

    2009-03-01

    The objective of the constellation acquisition phase for the LISA mission is to establish the three laser links between the three spacecraft of the LISA constellation so that the interferometric measurements for the science experiment can commence. The laser beam acquisition for LISA is extremely challenging given the 5 million km distance between the spacecraft, the inherent limits of the attitude sensors accuracy, the orbit determination accuracy issues and the time required to phase-lock the incoming and outgoing laser signals. This paper presents the design of the control system for the acquisition phase of the LISA constellation: the acquisition operational procedure is outlined, guidance laws are defined together with the Gyro Mode attitude control principle, which implements a Kalman filter for disturbances rejection purposes. Constellation-wide non-linear simulations demonstrate that the LISA constellation acquisition phase is feasible by means of the proposed control strategy.

  19. Control system design for the constellation acquisition phase of the LISA mission

    International Nuclear Information System (INIS)

    Cirillo, Francesca; Gath, Peter F

    2009-01-01

    The objective of the constellation acquisition phase for the LISA mission is to establish the three laser links between the three spacecraft of the LISA constellation so that the interferometric measurements for the science experiment can commence. The laser beam acquisition for LISA is extremely challenging given the 5 million km distance between the spacecraft, the inherent limits of the attitude sensors accuracy, the orbit determination accuracy issues and the time required to phase-lock the incoming and outgoing laser signals. This paper presents the design of the control system for the acquisition phase of the LISA constellation: the acquisition operational procedure is outlined, guidance laws are defined together with the Gyro Mode attitude control principle, which implements a Kalman filter for disturbances rejection purposes. Constellation-wide non-linear simulations demonstrate that the LISA constellation acquisition phase is feasible by means of the proposed control strategy.

  20. Fabrication and characterization of hybrid Nb-YBCO dc SQUIDs

    International Nuclear Information System (INIS)

    Frack, E.K.; Drake, R.E.; Patt, R.; Radparvar, M.

    1991-01-01

    This paper reports on the fabrication of hybrid low T c /high T c dc SQUIDs of two flavors. The first kind utilizes niobium tunnel junctions and a YBCO film strip as the most inductive portion of the SQUID loop. This configuration allows a direct measurement of the inductance of the YBCO microstrip from which the effective penetration depth can be calculated. The successful fabrication of these SQUIDs has required 1. superconducting Nb-to-YBCO contacts, 2. deposition and patterning of an SiO 2 insulation layer over YBCO, and 3. selective patterning of niobium and SiO 2 relative to YBCO. All these process steps are pertinent to the eventual use of YBCO thin films in electronic devices

  1. Relativistic analysis of the LISA long range optical links

    International Nuclear Information System (INIS)

    Chauvineau, Bertrand; Regimbau, Tania; Vinet, Jean-Yves; Pireaux, Sophie

    2005-01-01

    The joint ESA/NASA LISA mission consists of three spacecraft on heliocentric orbits, flying in a triangular formation of 5 Mkm each side, linked by infrared optical beams. The aim of the mission is to detect gravitational waves in a low frequency band. For properly processing the scientific data, the propagation delays between spacecraft must be accurately known. We thus analyze the propagation of light between spacecraft in order to systematically derive the relativistic effects due to the static curvature of the Schwarzschild space-time in which the spacecraft are orbiting with time-varying light distances. In particular, our analysis allows us to evaluate rigorously the Sagnac effect, and the gravitational (Einstein) redshift

  2. LISA Pathfinder drag-free control and system implications

    International Nuclear Information System (INIS)

    Fichter, Walter; Gath, Peter; Vitale, Stefano; Bortoluzzi, Daniele

    2005-01-01

    The top-level requirement of the LISA Pathfinder mission is the verification of pure relative free fall between two test masses with an accuracy of about 3 x 10 -14 m s -2 Hz -1/2 in a measurement bandwidth between 1 mHz and 30 mHz. The drag-free control system is one of the key technology elements that shall be verified. Its design is strongly connected to the overall system and experimental design, in particular, via the following issues: the differential test mass motion and thus the science measurements depend on the control system; design constraints, such as negative stiffness of test masses and electrostatic actuation cross-talk, have an impact on science and control system performance; derived requirements for control system components, in particular, the micro-propulsion system, must be within reasonable and feasible limits. In this paper, the control design approach is outlined and the system-related issues are addressed

  3. The LISA Pathfinder interferometry-hardware and system testing

    Energy Technology Data Exchange (ETDEWEB)

    Audley, H; Danzmann, K; MarIn, A Garcia; Heinzel, G; Monsky, A; Nofrarias, M; Steier, F; Bogenstahl, J [Albert-Einstein-Institut, Max-Planck-Institut fuer Gravitationsphysik und Universitaet Hannover, 30167 Hannover (Germany); Gerardi, D; Gerndt, R; Hechenblaikner, G; Johann, U; Luetzow-Wentzky, P; Wand, V [EADS Astrium GmbH, Friedrichshafen (Germany); Antonucci, F [Dipartimento di Fisica, Universita di Trento and INFN, Gruppo Collegato di Trento, 38050 Povo, Trento (Italy); Armano, M [European Space Astronomy Centre, European Space Agency, Villanueva de la Canada, 28692 Madrid (Spain); Auger, G; Binetruy, P [APC UMR7164, Universite Paris Diderot, Paris (France); Benedetti, M [Dipartimento di Ingegneria dei Materiali e Tecnologie Industriali, Universita di Trento and INFN, Gruppo Collegato di Trento, Mesiano, Trento (Italy); Boatella, C, E-mail: antonio.garcia@aei.mpg.de [CNES, DCT/AQ/EC, 18 Avenue Edouard Belin, 31401 Toulouse, Cedex 9 (France)

    2011-05-07

    Preparations for the LISA Pathfinder mission have reached an exciting stage. Tests of the engineering model (EM) of the optical metrology system have recently been completed at the Albert Einstein Institute, Hannover, and flight model tests are now underway. Significantly, they represent the first complete integration and testing of the space-qualified hardware and are the first tests on an optical system level. The results and test procedures of these campaigns will be utilized directly in the ground-based flight hardware tests, and subsequently during in-flight operations. In addition, they allow valuable testing of the data analysis methods using the MATLAB-based LTP data analysis toolbox. This paper presents an overview of the results from the EM test campaign that was successfully completed in December 2009.

  4. Commissioning and operating experience with the LISA superconducting accelerator

    International Nuclear Information System (INIS)

    Castellano, M.; Ferrario, M.; Minestrini, M.; Patteri, P.; Tazzioli, F.; Kulinski, S.

    1996-06-01

    The commissioning of the LISA superconducting (SC) RF electron linac at INFN Frascati Laboratories has been concluded although, due to a change in program priorities, the full possibilities of the machine have not been exploited. In this report the authors illustrate the results achieved so far and the difficulties encountered in commissioning, with the hope that this material might be some of help to those who intend to start the enterprise of building a SC linac in a non specialized environment. The part concerning the SC system is particularly stressed, but a relevant attention is also devoted to the traditional room temperature injector, the proper setting of which is fundamental to achieving the high beam quality that such a machine allows

  5. Detecting white dwarf binaries in Mock LISA Data Challenge 3

    International Nuclear Information System (INIS)

    Blaut, A; Krolak, A; Babak, S

    2009-01-01

    We present a strategy for detecting gravitational wave signals from the Galactic white dwarf binaries in the Mock LISA Data Challenge 3 (MLDC3) and estimate their parameters. Our method is based on the matched filtering in the form of the F-statistic. We perform the search on three-dimensional space (sky coordinate and frequency of gravitational wave) below 3 mHz and include the fourth parameter (frequency derivative) at high frequencies. A template bank is used to search for the strongest signal in the data, then we remove it and repeat the search until we do not have signals in the data above a preselected threshold. For the template bank, we construct an optimal grid that realizes the best lattice covering with a constraint such that the nodes of the grid coincide with the Fourier frequencies. This enables the use of the fast Fourier transform algorithm to calculate the F-statistic.

  6. Strong lensing of gravitational waves as seen by LISA.

    Science.gov (United States)

    Sereno, M; Sesana, A; Bleuler, A; Jetzer, Ph; Volonteri, M; Begelman, M C

    2010-12-17

    We discuss strong gravitational lensing of gravitational waves from the merging of massive black hole binaries in the context of the LISA mission. Detection of multiple events would provide invaluable information on competing theories of gravity, evolution and formation of structures and, possibly, constraints on H0 and other cosmological parameters. Most of the optical depth for lensing is provided by intervening massive galactic halos, for which wave optics effects are negligible. Probabilities to observe multiple events are sizable for a broad range of formation histories. For the most optimistic models, up to ≲ 4 multiple events with a signal to noise ratio ≳ 8 are expected in a 5-year mission. Chances are significant even for conservative models with either light (≲ 60%) or heavy (≲ 40%) seeds. Because of lensing amplification, some intrinsically too faint signals are brought over threshold (≲ 2 per year).

  7. Interferometry for the LISA technology package (LTP) aboard SMART-2

    International Nuclear Information System (INIS)

    Heinzel, G; Braxmaier, C; Schilling, R; Ruediger, A; Robertson, D; Plate, M te; Wand, V; Arai, K; Johann, U; Danzmann, K

    2003-01-01

    The interferometer of the LISA technology package (LTP) on SMART-2 is needed to verify the performance of the gravitational sensors by monitoring the distance between two test masses with a noise level of 10 pm Hz -1/2 between 3 mHz and 30 mHz. It must continuously track the motion of the test mass distance while that distance changes by many μm with a speed of up to 20 μm s -1 , without losing track of the sign of the motion and without exerting any influence on the test masses that might lead to a motion above that level. As a result of a detailed comparison study, a heterodyne Mach-Zehnder interferometer was selected as the baseline for the SMART-2 mission. Its design and expected performance are described in this paper

  8. The effects of orbital motion on LISA time delay interferometry

    International Nuclear Information System (INIS)

    Cornish, Neil J; Hellings, Ronald W

    2003-01-01

    In an effort to eliminate laser phase noise in laser interferometer spaceborne gravitational wave detectors, several combinations of signals have been found that allow the laser noise to be cancelled out while gravitational wave signals remain. This process is called time delay interferometry (TDI). In the papers that defined the TDI variables, their performance was evaluated in the limit that the gravitational wave detector is fixed in space. However, the performance depends on certain symmetries in the armlengths that are available if the detector is fixed in space, but that will be broken in the actual rotating and flexing configuration produced by the LISA orbits. In this paper we investigate the performance of these TDI variables for the real LISA orbits. First, addressing the effects of rotation, we verify Daniel Shaddock's result that the Sagnac variables α (t), β (t) and γ (t) will not cancel out the laser phase noise, and we also find the same result for the symmetric Sagnac variable ζ (t). The loss of the latter variable would be particularly unfortunate since this variable also cancels out gravitational wave signal, allowing instrument noise in the detector to be isolated and measured. Fortunately, we have found a set of more complicated TDI variables, which we call Δ Sagnac variables, one of which accomplishes the same goal as ζ (t) to good accuracy. Finally, however, as we investigate the effects of the flexing of the detector arms due to non-circular orbital motion, we show that all variables, including the interferometer variables, X(t), Y(t) and Z(t), which survive the rotation-induced loss of direction symmetry, will not completely cancel laser phase noise when the armlengths are changing with time. This unavoidable problem will place a stringent requirement on laser stability of ∼5 Hz Hz -1/2

  9. Dipole location using SQUID based measurements: Application to magnetocardiography

    Science.gov (United States)

    Mariyappa, N.; Parasakthi, C.; Sengottuvel, S.; Gireesan, K.; Patel, Rajesh; Janawadkar, M. P.; Sundar, C. S.; Radhakrishnan, T. S.

    2012-07-01

    We report a method of inferring the dipole location using iterative nonlinear least square optimization based on Levenberg-Marquardt algorithm, wherein, we use different sets of pseudo-random numbers as initial parameter values. The method has been applied to (i) the simulated data representing the calculated magnetic field distribution produced by a point dipole placed at a known position, (ii) the experimental data from SQUID based measurements of the magnetic field distribution produced by a source coil carrying current, and (iii) the actual experimentally measured magnetocardiograms of human subjects using a SQUID based system.

  10. Application of squids in the Iwate create project

    International Nuclear Information System (INIS)

    Yoshizawa, M.; He, D.F.; Nakai, K.; Kobayashi, K.; Nakamura, Y.; Yaegashi, M.; Ito, M.; Yashiro, H.; Daibo, M.; Simizu, T.; Uchikawa, Y.; Noto, K.

    2005-01-01

    We have developed a 64-channel magnetocardiograph (MCG) system for the diagnosis of heart disease. The MCG is characterized by its display of a unique three-dimensional image of bio-currents flowing inside the human body. The outline of the heart can be displayed without use of MRI. A mobile SQUID-based non-distractive evaluation apparatus was realized by the active shielding technique. The system can offer information from beneath the surface of the specimen by using a saw-wave excitation method. This mobile technology enables us to inspect ferromagnetic materials, whose high magnetic field rules out the use of a conventional SQUID apparatus near them

  11. Scanning high-Tc SQUID imaging system for magnetocardiography

    International Nuclear Information System (INIS)

    Yang, H-C; Wu, T-Y; Horng, H-E; Wu, C-C; Yang, S Y; Liao, S-H; Wu, C-H; Jeng, J T; Chen, J C; Chen, Kuen-Lin; Chen, M J

    2006-01-01

    A scanning magnetocardiography (MCG) system constructed from SQUID sensors offers potential to basic or clinical research in biomagnetism. In this work, we study a first order scanning electronic high-T c (HTS) SQUID MCG system for biomagnetic signals. The scanning MCG system was equipped with an x-y translation bed powered by step motors. Using noise cancellation and μ-metal shielding, we reduced the noise level substantially. The established scanning HTS MCG system was used to study the magnetophysiology of hypercholesterolaemic (HC) rabbits. The MCG data of HC rabbits were analysed. The MCG contour map of HC rabbits provides experimental models for the interpretation of human cardiac patterns

  12. THE LISA GRAVITATIONAL WAVE FOREGROUND: A STUDY OF DOUBLE WHITE DWARFS

    International Nuclear Information System (INIS)

    Ruiter, Ashley J.; Belczynski, Krzysztof; Benacquista, Matthew; Williams, Gabriel; Larson, Shane L.

    2010-01-01

    Double white dwarfs (WDs) are expected to be a source of confusion-limited noise for the future gravitational wave observatory LISA. In a specific frequency range, this 'foreground noise' is predicted to rise above the instrumental noise and hinder the detection of other types of signals, e.g., gravitational waves arising from stellar-mass objects inspiraling into massive black holes. In many previous studies, only detached populations of compact object binaries have been considered in estimating the LISA gravitational wave foreground signal. Here, we investigate the influence of compact object detached and Roche-Lobe overflow (RLOF) Galactic binaries on the shape and strength of the LISA signal. Since >99% of remnant binaries that have orbital periods within the LISA sensitivity range are WD binaries, we consider only these binaries when calculating the LISA signal. We find that the contribution of RLOF binaries to the foreground noise is negligible at low frequencies, but becomes significant at higher frequencies, pushing the frequency at which the foreground noise drops below the instrumental noise to >6 mHz. We find that it is important to consider the population of mass-transferring binaries in order to obtain an accurate assessment of the foreground noise on the LISA data stream. However, we estimate that there still exists a sizeable number (∼11,300) of Galactic double WD binaries that will have a signal-to-noise ratio >5, and thus will be potentially resolvable with LISA. We present the LISA gravitational wave signal from the Galactic population of WD binaries, show the most important formation channels contributing to the LISA disk and bulge populations, and discuss the implications of these new findings.

  13. Annual modulation of the galactic binary confusion noise background and LISA data analysis

    International Nuclear Information System (INIS)

    Seto, Naoki

    2004-01-01

    We study the anisotropies of the galactic confusion noise background and its effects on LISA data analysis. LISA has two data streams of gravitational wave signals relevant for the low frequency regime. Because of the anisotropies of the background, the matrix for their confusion noises has off-diagonal components and depends strongly on the orientation of the detector plane. We find that the sky-averaged confusion noise level √(S(f)) could change by a factor of 2 in 3 months and would be minimum when the orbital position of LISA is around either the spring or autumn equinox

  14. Science with the space-based interferometer LISA. IV: probing inflation with gravitational waves

    International Nuclear Information System (INIS)

    Bartolo, Nicola; Guzzetti, Maria Chiara; Liguori, Michele; Matarrese, Sabino

    2016-01-01

    We investigate the potential for the LISA space-based interferometer to detect the stochastic gravitational wave background produced from different mechanisms during inflation. Focusing on well-motivated scenarios, we study the resulting contributions from particle production during inflation, inflationary spectator fields with varying speed of sound, effective field theories of inflation with specific patterns of symmetry breaking and models leading to the formation of primordial black holes. The projected sensitivities of LISA are used in a model-independent way for various detector designs and configurations. We demonstrate that LISA is able to probe these well-motivated inflationary scenarios beyond the irreducible vacuum tensor modes expected from any inflationary background.

  15. Science with the space-based interferometer LISA. IV: Probing inflation with gravitational waves

    CERN Document Server

    Bartolo, Nicola; Domcke, Valerie; Figueroa, Daniel G.; Garcia-Bellido, Juan; Guzzetti, Maria Chiara; Liguori, Michele; Matarrese, Sabino; Peloso, Marco; Petiteau, Antoine; Ricciardone, Angelo; Sakellariadou, Mairi; Sorbo, Lorenzo; Tasinato, Gianmassimo

    2016-01-01

    We investigate the potential for the LISA space-based interferometer to detect the stochastic gravitational wave background produced from different mechanisms during inflation. Focusing on well-motivated scenarios, we study the resulting contributions from particle production during inflation, inflationary spectator fields with varying speed of sound, effective field theories of inflation with specific patterns of symmetry breaking and models leading to the formation of primordial black holes. The projected sensitivities of LISA are used in a model-independent way for various detector designs and configurations. We demonstrate that LISA is able to probe these well-motivated inflationary scenarios beyond the irreducible vacuum tensor modes expected from any inflationary background.

  16. Can understanding squid life-history strategies and recruitment ...

    African Journals Online (AJOL)

    Current views of the links between life-history strategies and recruitment processes in fish are contrasted with the pattern emerging for squid. A general perspective is that the roles of space and time are reversed in the two groups, suggesting that management strategies also should differ. The space/time reversal appears to ...

  17. Scanning SQUID susceptometers with sub-micron spatial resolution

    International Nuclear Information System (INIS)

    Kirtley, John R.; Rosenberg, Aaron J.; Palmstrom, Johanna C.; Holland, Connor M.; Moler, Kathryn A.; Paulius, Lisa; Spanton, Eric M.; Schiessl, Daniel; Jermain, Colin L.; Gibbons, Jonathan; Fung, Y.-K.K.; Gibson, Gerald W.; Huber, Martin E.; Ralph, Daniel C.; Ketchen, Mark B.

    2016-01-01

    Superconducting QUantum Interference Device (SQUID) microscopy has excellent magnetic field sensitivity, but suffers from modest spatial resolution when compared with other scanning probes. This spatial resolution is determined by both the size of the field sensitive area and the spacing between this area and the sample surface. In this paper we describe scanning SQUID susceptometers that achieve sub-micron spatial resolution while retaining a white noise floor flux sensitivity of ≈2μΦ_0/Hz"1"/"2. This high spatial resolution is accomplished by deep sub-micron feature sizes, well shielded pickup loops fabricated using a planarized process, and a deep etch step that minimizes the spacing between the sample surface and the SQUID pickup loop. We describe the design, modeling, fabrication, and testing of these sensors. Although sub-micron spatial resolution has been achieved previously in scanning SQUID sensors, our sensors not only achieve high spatial resolution but also have integrated modulation coils for flux feedback, integrated field coils for susceptibility measurements, and batch processing. They are therefore a generally applicable tool for imaging sample magnetization, currents, and susceptibilities with higher spatial resolution than previous susceptometers.

  18. The magnapinnidae, a newly discovered family of oceanic Squid ...

    African Journals Online (AJOL)

    A peculiar squid paralarva from Hawaiian waters was described by Young (1991, Bull. mar. Sci. 49(1–2): 162–185), but it could not be assigned to any known family. Two larger juvenile specimens have now been obtained, one collected near the surface in the eastern Pacific Ocean and the other rehydrated from a dried ...

  19. A mass stranding of the squid martialia hyadesi Rochebrune and ...

    African Journals Online (AJOL)

    1997-02-11

    Feb 11, 1997 ... All animals were immature, with females in lower stages of maturity than males. No predatory marine mammals were seen in the area during or after the stranding event. An interpretation of the stranding is presented with reference to historical reports of squid strandings worldwide. Evidence suggests some ...

  20. Review of Magneto cardiography Technology based on SQUID

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Y. H.; Kwon, H.; Kim, J. M.; Kim, K.; Yu, K. K.; Park, Y. K. [Brain and Cognition Measurement Lab, Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of)

    2012-04-15

    Electric activity of cardiac muscles generates magnetic fields. Magnetocardiography (or MCG) technology, measuring these magnetic signals, can provide useful information for the diagnosis of heart diseases. It is already about 40 years ago that the first measurement of MCG signals was done by D. Cohen using SQUID (superconducting quantum interference device) sensor inside a magnetically shielded room. In the early period of MCG history, bulky point-contact RF-SQUID was used as the magnetic sensor. Thanks to the development of Nb-based Josephson junction technology in mid 1980s and new design of tightly-coupled DC-SQUID, low-noise SQUID sensors could be developed in late 1980s. In around 1990, several groups developed multi-channel MCG systems and started clinical study. However, it is quite recent years that the true usefulness of MCG was verified in clinical practice, for example, in the diagnosis of coronary artery disease. For the practical MCG system, technical elements of MCG system should be optimized in terms of performance, fabrication cost and operation cost. In this review, development history, technical issue, and future development direction of MCG technology are described.

  1. Scanning SQUID susceptometers with sub-micron spatial resolution

    Energy Technology Data Exchange (ETDEWEB)

    Kirtley, John R., E-mail: jkirtley@stanford.edu; Rosenberg, Aaron J.; Palmstrom, Johanna C.; Holland, Connor M.; Moler, Kathryn A. [Department of Applied Physics, Stanford University, Stanford, California 94305-4045 (United States); Paulius, Lisa [Department of Physics, Western Michigan University, Kalamazoo, Michigan 49008-5252 (United States); Spanton, Eric M. [Department of Physics, Stanford University, Stanford, California 94305-4045 (United States); Schiessl, Daniel [Attocube Systems AG, Königinstraße 11A, 80539 Munich (Germany); Jermain, Colin L.; Gibbons, Jonathan [Department of Physics, Cornell University, Cornell, Ithaca, New York 14853 (United States); Fung, Y.-K.K.; Gibson, Gerald W. [IBM Research Division, T. J. Watson Research Center, Yorktown Heights, New York 10598 (United States); Huber, Martin E. [Department of Physics, University of Colorado Denver, Denver, Colorado 80217-3364 (United States); Ralph, Daniel C. [Department of Physics, Cornell University, Cornell, Ithaca, New York 14853 (United States); Kavli Institute at Cornell, Ithaca, New York 14853 (United States); Ketchen, Mark B. [OcteVue, Hadley, Massachusetts 01035 (United States)

    2016-09-15

    Superconducting QUantum Interference Device (SQUID) microscopy has excellent magnetic field sensitivity, but suffers from modest spatial resolution when compared with other scanning probes. This spatial resolution is determined by both the size of the field sensitive area and the spacing between this area and the sample surface. In this paper we describe scanning SQUID susceptometers that achieve sub-micron spatial resolution while retaining a white noise floor flux sensitivity of ≈2μΦ{sub 0}/Hz{sup 1/2}. This high spatial resolution is accomplished by deep sub-micron feature sizes, well shielded pickup loops fabricated using a planarized process, and a deep etch step that minimizes the spacing between the sample surface and the SQUID pickup loop. We describe the design, modeling, fabrication, and testing of these sensors. Although sub-micron spatial resolution has been achieved previously in scanning SQUID sensors, our sensors not only achieve high spatial resolution but also have integrated modulation coils for flux feedback, integrated field coils for susceptibility measurements, and batch processing. They are therefore a generally applicable tool for imaging sample magnetization, currents, and susceptibilities with higher spatial resolution than previous susceptometers.

  2. A contribution to the biology of the ommastrephid squid Martialia ...

    African Journals Online (AJOL)

    Updated knowledge on the distribution and biology of the ommastrephid squid Martialia hyadesi in the South-West Atlantic Ocean is presented. Although the species has an Antarctic circumpolar distribution, its most frequent area of appearance is in the South-West Atlantic, where commercial catches have been made.

  3. Reducing systematic errors in measurements made by a SQUID magnetometer

    International Nuclear Information System (INIS)

    Kiss, L.F.; Kaptás, D.; Balogh, J.

    2014-01-01

    A simple method is described which reduces those systematic errors of a superconducting quantum interference device (SQUID) magnetometer that arise from possible radial displacements of the sample in the second-order gradiometer superconducting pickup coil. By rotating the sample rod (and hence the sample) around its axis into a position where the best fit is obtained to the output voltage of the SQUID as the sample is moved through the pickup coil, the accuracy of measuring magnetic moments can be increased significantly. In the cases of an examined Co 1.9 Fe 1.1 Si Heusler alloy, pure iron and nickel samples, the accuracy could be increased over the value given in the specification of the device. The suggested method is only meaningful if the measurement uncertainty is dominated by systematic errors – radial displacement in particular – and not by instrumental or environmental noise. - Highlights: • A simple method is described which reduces systematic errors of a SQUID. • The errors arise from a radial displacement of the sample in the gradiometer coil. • The procedure is to rotate the sample rod (with the sample) around its axis. • The best fit to the SQUID voltage has to be attained moving the sample through the coil. • The accuracy of measuring magnetic moment can be increased significantly

  4. A method of background noise cancellation for SQUID applications

    International Nuclear Information System (INIS)

    He, D F; Yoshizawa, M

    2003-01-01

    When superconducting quantum inference devices (SQUIDs) operate in low-cost shielding or unshielded environments, the environmental background noise should be reduced to increase the signal-to-noise ratio. In this paper we present a background noise cancellation method based on a spectral subtraction algorithm. We first measure the background noise and estimate the noise spectrum using fast Fourier transform (FFT), then we subtract the spectrum of background noise from that of the observed noisy signal and the signal can be reconstructed by inverse FFT of the subtracted spectrum. With this method, the background noise, especially stationary inferences, can be suppressed well and the signal-to-noise ratio can be increased. Using high-T C radio-frequency SQUID gradiometer and magnetometer, we have measured the magnetic field produced by a watch, which was placed 35 cm under a SQUID. After noise cancellation, the signal-to-noise ratio could be greatly increased. We also used this method to eliminate the vibration noise of a cryocooler SQUID

  5. Flicker (1/f) noise in tunnel junction DC SQUIDS

    International Nuclear Information System (INIS)

    Koch, R.H.; Clarke, J.; Goubau, W.M.; Martinis, J.M.; Pegrum, C.M.; Van Harlingen, D.J.

    1983-01-01

    We have measured the spectral density of the 1/f voltage noise in current-biased resistively shunted Josephson tunnel junctions and dc SQUIDs. A theory in which fluctuations in the temperature give rise to fluctuations in the critical current and hence in the voltage predicts the magnitude of the noise quite accurately for junctions with areas of about 2 x 10 4 μm 2 , but significantly overestimates the noise for junctions with areas of about 6 μm 2 . DC SQUIDs fabricated from these two types of junctions exhibit substantially more 1/f voltage noise than would be predicted from a model in which the noise arises from critical current fluctuations in the junctions. This result was confirmed by an experiment involving two different bias current and flux modulation schemes, which demonstrated that the predominant 1/f voltage noise arises not from critical current fluctuations, but from some unknown source that can be regarded as an apparent 1/f flux noise. Measurements on five different configurations of dc SQUIDs fabricated with thin-film tunnel junctions and with widely varying areas, inductances, and junction capacitances show that the spectral density of the 1/f equivalent flux noise is roughtly constant, within a factor of three of (10 -10 /f)phi 2 0 Hz -1 . It is emphasized that 1/f flux noise may not be the predominant source of 1/f noise in SQUIDS fabricated with other technologies

  6. SQUID developments for the gravitational wave antenna MiniGRAIL

    NARCIS (Netherlands)

    Pleikies, J.; Usenko, O.; Kuit, K.H.; Flokstra, Jakob; de Waard, A.; de Waard, A.; Frossati, G.

    2007-01-01

    We designed two different sensor SQUIDs for the readout of the resonant mass gravitational wave detector MiniGRAIL. Both designs have integrated input inductors in the order of 1.5 muH and are planned for operation in the mK temperature range. Cooling fins were added to the shunt resistors. The

  7. The biomass and ecology of chokka squid Loligo vulgaris reynaudii ...

    African Journals Online (AJOL)

    Migration, stock size and ecology of chokka squid Loligo vulgaris reynaudii off the West Coast of South Africa were studied and their relationship to other regions compared by analysis of distributional, biomass, and size composition, and biological data collected from biannual research cruises from 1983-1987. Biomass ...

  8. spawning grounds for chokka squid Loligo vulgaris reynaudii, using

    African Journals Online (AJOL)

    denise

    Swimming movements in relation to egg beds have been studied using acoustic micro-electronic transmitters implanted in squid and tracked via 3-D radio-linked acoustic positioning telemetry (O'Dor et al. 1996, 1998, Sauer et al. 1997). Most of these methods are either impractical or would be severely limited on the deeper ...

  9. Radiation pressure calibration and test mass reflectivities for LISA Pathfinder

    International Nuclear Information System (INIS)

    Korsakova, Natalia; Kaune, Brigitte

    2017-01-01

    This paper describes a series of experiments which were carried out during the main operations of LISA Pathfinder. These experiments were performed by modulating the power of the measurement and reference beams. In one series of experiments the beams were sequentially switched on and off. In the other series of experiments the powers of the beams were modulated within 0.1% and 1% of the constant power. These experiments use recordings of the total power measured on the photodiodes to infer the properties of the Optical Metrology System (OMS), such as reflectivities of the test masses and change of the photodiode efficiencies with time. In the first case the powers are back propagated from the different photodiodes to the same place on the optical bench to express the unknown quantities in the measurement with the complimentary photodiode measurements. They are combined in the way that the only unknown left is the test mass reflectivities. The second experiment compared two estimates of the force applied to the test masses due to the radiation pressure that appears because of the beam modulations. One estimate of the force is inferred from the measurements of the powers on the photodiodes and propagation of this measurement to the test masses. The other estimation of the force is done by calculating it from the change in the main scientific output of the instrument – differential displacement of the two test masses. (paper)

  10. Analog phase lock between two lasers at LISA power levels

    International Nuclear Information System (INIS)

    Diekmann, Christian; Steier, Frank; Sheard, Benjamin; Heinzel, Gerhard; Danzmann, Karsten

    2009-01-01

    This paper presents the implementation of an analog optical phase-locked-loop with an offset frequency of about 20MHz between two lasers, where the detected light powers were of the order of 31 pW and 200 μW. The goal of this setup was the design and characterization of a photodiode transimpedance amplifier for application in LISA. By application of a transimpedance amplifier designed to have low noise and low power consumption, the phase noise between the two lasers was a factor of two above the shot noise limit down to 60mHz. The achievable phase sensitivity depends ultimately on the available power of the highly attenuated master laser and on the input current noise of the transimpedance amplifier of the photodetector. The limiting noise source below 60mHz was the analog phase measurement system that was used in this experiment. A digital phase measurement system that is currently under development at the AEI will be used in the near future. Its application should improve the sensitivity.

  11. Analog phase lock between two lasers at LISA power levels

    Energy Technology Data Exchange (ETDEWEB)

    Diekmann, Christian; Steier, Frank; Sheard, Benjamin; Heinzel, Gerhard; Danzmann, Karsten, E-mail: Christian.Diekmann@aei.mpg.d [Max-Planck-Institute for Gravitational Physics, Callinstr. 38, D-30167 Hannover (Germany)

    2009-03-01

    This paper presents the implementation of an analog optical phase-locked-loop with an offset frequency of about 20MHz between two lasers, where the detected light powers were of the order of 31 pW and 200 muW. The goal of this setup was the design and characterization of a photodiode transimpedance amplifier for application in LISA. By application of a transimpedance amplifier designed to have low noise and low power consumption, the phase noise between the two lasers was a factor of two above the shot noise limit down to 60mHz. The achievable phase sensitivity depends ultimately on the available power of the highly attenuated master laser and on the input current noise of the transimpedance amplifier of the photodetector. The limiting noise source below 60mHz was the analog phase measurement system that was used in this experiment. A digital phase measurement system that is currently under development at the AEI will be used in the near future. Its application should improve the sensitivity.

  12. Radiation pressure calibration and test mass reflectivities for LISA Pathfinder

    Science.gov (United States)

    Korsakova, Natalia; Kaune, Brigitte; LPF Collaboration

    2017-05-01

    This paper describes a series of experiments which were carried out during the main operations of LISA Pathfinder. These experiments were performed by modulating the power of the measurement and reference beams. In one series of experiments the beams were sequentially switched on and off. In the other series of experiments the powers of the beams were modulated within 0.1% and 1% of the constant power. These experiments use recordings of the total power measured on the photodiodes to infer the properties of the Optical Metrology System (OMS), such as reflectivities of the test masses and change of the photodiode efficiencies with time. In the first case the powers are back propagated from the different photodiodes to the same place on the optical bench to express the unknown quantities in the measurement with the complimentary photodiode measurements. They are combined in the way that the only unknown left is the test mass reflectivities. The second experiment compared two estimates of the force applied to the test masses due to the radiation pressure that appears because of the beam modulations. One estimate of the force is inferred from the measurements of the powers on the photodiodes and propagation of this measurement to the test masses. The other estimation of the force is done by calculating it from the change in the main scientific output of the instrument - differential displacement of the two test masses.

  13. Planning for chemical disasters at Point Lisas, Trinidad and Tobago

    International Nuclear Information System (INIS)

    Mathur, M.N.

    1995-01-01

    No major chemical disaster has taken place so far in Trinidad and Tobago. Even so, in view of the numerous hazards that the various chemical handling plants deal with at Point Lisas, the country has to be prepared to deal with chemical disasters. The country's emergency preparedness plan for chemical disasters aims to localize the emergency, if possible, eliminate it and minimize the effects of the accident on people and property. The hazards of ammonia, hydrogen, chlorine, hydrocarbons and methanol release can have devastating effects on the workers and the residents in the vicinity of the plants. The Emergency Plan identifies an Emergency Co-ordinating Officer who would take command of the off-site activities and coordinate the activities of Works Management, Local Authority, Police, Fire Services, Defence Force, Health Authority and Factory Inspectorate. Resources of fire fighting, medical treatment, telecommunications, waste management and public education have to be enhanced immediately. In the long term a new fire station and a new county hospital have to be built, some housing settlements have to be phased out and non-essential staff relocated

  14. LISA Pathfinder: An important first step towards a space-based gravitational wave observatory

    Science.gov (United States)

    Thorpe, James

    2017-08-01

    ESA's LISA Pathfinder mission was launched on Dec 3rd, 2015 and completed earlier this Summer. During this relatively short mission, Pathfinder at its two science payloads, Europe's LISA Technology Package and NASA's Disturbance Reduction System, demonstrated several techniques and technologies that enable development of a future space-based gravitational wave observatory. Most notably, Pathfinder demonstrated that the technique of drag-free flight could be utilized to place a test mass in near-perfect free-fall, with residual accelerations at the femto-g level in the milliHertz band. Additionally, technologies such as precision bonded optical structures for metrology, micropropulsion systems, and non-contact charge control, were successfully tested, retiring risk for LISA. In this talk, I will present an overview of Pathfinder's results to date and some perspective on how this success will be leveraged into realizing LISA.

  15. Report on the first round of the Mock LISA Data Challenges

    International Nuclear Information System (INIS)

    Arnaud, K A; Auger, G; Babak, S

    2007-01-01

    The Mock LISA Data Challenges (MLDCs) have the dual purpose of fostering the development of LISA data analysis tools and capabilities, and demonstrating the technical readiness already achieved by the gravitational-wave community in distilling a rich science payoff from the LISA data output. The first round of MLDCs has just been completed: nine challenges consisting of data sets containing simulated gravitational-wave signals produced either by galactic binaries or massive black hole binaries embedded in simulated LISA instrumental noise were released in June 2006 with deadline for submission of results at the beginning of December 2006. Ten groups have participated in this first round of challenges. All of the challenges had at least one entry which successfully characterized the signal to better than 95% when assessed via a correlation with phasing ambiguities accounted for. Here, we describe the challenges, summarize the results and provide a first critical assessment of the entries

  16. Far infrared through millimeter backshort-under-grid arrays

    Science.gov (United States)

    Allen, Christine A.; Abrahams, John; Benford, Dominic J.; Chervenak, James A.; Chuss, David T.; Staguhn, Johannes G.; Miller, Timothy M.; Moseley, S. Harvey; Wollack, Edward J.

    2006-06-01

    We are developing a large-format, versatile, bolometer array for a wide range of infrared through millimeter astronomical applications. The array design consists of three key components - superconducting transition edge sensor bolometer arrays, quarter-wave reflective backshort grids, and Superconducting Quantum Interference Device (SQUID) multiplexer readouts. The detector array is a filled, square grid of bolometers with superconducting sensors. The backshort arrays are fabricated separately and are positioned in the etch cavities behind the detector grid. The grids have unique three-dimensional interlocking features micromachined into the walls for positioning and mechanical stability. The ultimate goal of the program is to produce large-format arrays with background-limited sensitivity, suitable for a wide range of wavelengths and applications. Large-format (kilopixel) arrays will be directly indium bump bonded to a SQUID multiplexer circuit. We have produced and tested 8×8 arrays of 1 mm detectors to demonstrate proof of concept. 8×16 arrays of 2 mm detectors are being produced for a new Goddard Space Flight Center instrument. We have also produced models of a kilopixel detector grid and dummy multiplexer chip for bump bonding development. We present detector design overview, several unique fabrication highlights, and assembly technologies.

  17. Stellar binary black holes in the LISA band: a new class of standard sirens

    Science.gov (United States)

    Del Pozzo, Walter; Sesana, Alberto; Klein, Antoine

    2018-04-01

    The recent Advanced LIGO detections of coalescing black hole binaries (BHBs) imply a large population of such systems emitting at milli-Hz frequencies, accessible to the Laser Interferometer Space Antenna (LISA). We show that these systems provide a new class of cosmological standard sirens. Direct LISA luminosity distance - Dl - measurements, combined with the inhomogeneous redshift - z - distribution of possible host galaxies provide an effective way to populate the Dl-z diagram at z arm-length, respectively.

  18. LISA extreme-mass-ratio inspiral events as probes of the black hole mass function

    International Nuclear Information System (INIS)

    Gair, Jonathan R.; Tang, Christopher; Volonteri, Marta

    2010-01-01

    One of the sources of gravitational waves for the proposed space-based gravitational wave detector, the Laser Interferometer Space Antenna (LISA), are the inspirals of compact objects into supermassive black holes in the centers of galaxies--extreme-mass-ratio inspirals (EMRIs). Using LISA observations, we will be able to measure the parameters of each EMRI system detected to very high precision. However, the statistics of the set of EMRI events observed by LISA will be more important in constraining astrophysical models than extremely precise measurements for individual systems. The black holes to which LISA is most sensitive are in a mass range that is difficult to probe using other techniques, so LISA provides an almost unique window onto these objects. In this paper we explore, using Bayesian techniques, the constraints that LISA EMRI observations can place on the mass function of black holes at low redshift. We describe a general framework for approaching inference of this type--using multiple observations in combination to constrain a parametrized source population. Assuming that the scaling of the EMRI rate with the black-hole mass is known and taking a black-hole distribution given by a simple power law, dn/dlnM=A 0 (M/M * ) α 0 , we find that LISA could measure the parameters to a precision of Δ(lnA 0 )∼0.08, and Δ(α 0 )∼0.03 for a reference model that predicts ∼1000 events. Even with as few as 10 events, LISA should constrain the slope to a precision ∼0.3, which is the current level of observational uncertainty in the low-mass slope of the black-hole mass function. We also consider a model in which A 0 and α 0 evolve with redshift, but find that EMRI observations alone do not have much power to probe such an evolution.

  19. Constraining stellar binary black hole formation scenarios with eLISA eccentricity measurements

    OpenAIRE

    Nishizawa, Atsushi; Sesana, Alberto; Berti, Emanuele; Klein, Antoine

    2016-01-01

    A space-based interferometer such as eLISA could observe few to few thousands progenitors of black hole binaries (BHBs) similar to those recently detected by Advanced LIGO. Gravitational radiation circularizes the orbit during inspiral, but some BHBs retain a measurable eccentricity at the low frequencies where eLISA is most sensitive. The eccentricity of a BHB carries precious information about its formation channel: BHBs formed in the field, in globular clusters, or close to a massive black...

  20. Nuclear magnetic resonance with dc SQUID [Super-conducting QUantum Interference Device] preamplifiers

    International Nuclear Information System (INIS)

    Fan, N.Q.; Heaney, M.B.; Clark, J.; Newitt, D.; Wald, L.; Hahn, E.L.; Bierlecki, A.; Pines, A.

    1988-08-01

    Sensitive radio-frequency (rf) amplifiers based on dc Superconducting QUantum Interface Devices (SQUIDS) are available for frequencies up to 200 MHz. At 4.2 K, the gain and noise temperature of a typical tuned amplifier are 18.6 +- 0.5 dB and 1.7 +- 0.5 K at 93 MHz. These amplifiers are being applied to a series of novel experiments on nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR). The high sensitivity of these amplifiers was demonstrated in the observation of ''nuclear spin noise'', the emission of photons by 35 Cl nuclei in a state of zero polarization. In the more conventional experiments in which one applies a large rf pulse to the spins, a Q-spoiler, consisting of a series array of Josephson junctions, is used to reduce the Q of the input circuit to a very low value during the pulse. The Q-spoiler enables the circuit to recover quickly after the pulse, and has been used in an NQR experiment to achieve a sensitivity of about 2 /times/ 10 16 nuclear Bohr magnetons in a single free precession signal with a bandwidth of 10 kHz. In a third experiment, a sample containing 35 Cl nuclei was placed in a capacitor and the signal detected electrically using a tuned SQUID amplifier and Q-spoiler. In this way, the electrical polarization induced by the precessing Cl nuclear quadrupole moments was detected: this is the inverse of the Stark effect in NQR. Two experiments involving NMR have been carried out. In the first, the 30 MHz resonance in 119 Sn nuclei is detected with a tuned amplifier and Q-spoiler, and a single pulse resolution of 10 18 nuclear Bohr magnetons in a bandwidth of 25 kHz has been achieved. For the second, a low frequency NMR system has been developed that uses an untuned input circuit coupled to the SQUID. The resonance in 195 Pt nuclei has been observed at 55 kHz in a field of 60 gauss. 23 refs., 11 figs

  1. Magnetic shield effect simulation of superconducting film shield covering directly coupled HTS dc-SQUID magnetometer

    International Nuclear Information System (INIS)

    Terauchi, N.; Noguchi, S.; Igarashi, H.

    2011-01-01

    A superconducting film shield over a SQUID ring improves the robustness of the SQUID with respect to magnetic noise. Supercurrent in the SQUID magnetometer and the superconducting film shield were simulated. The superconducting film shield reduces the influence of the external magnetic field on the SQUID ring. An HTS SQUID is a high sensitive magnetic sensor. In recent years, the HTS SQUID is widely used in various applications. In some applications, high robustness with respect to magnetic noise is required to realize stable operation at outside of a magnetic shielding room. The target of this paper is a directly coupled HTS dc-SQUID magnetometer. To enhance the robustness of the SQUID magnetometer, use of a superconducting thin film shield has been proposed. The magnetic field directly penetrating the SQUID ring causes the change of the critical current of Josephson junction, and then the SQUID magnetometer transitions into inoperative state. In order to confirm the magnetic shield effect of the superconducting film shield, electromagnetic field simulation with 3D edge finite element method was performed. To simulate the high temperature superconductor, E-J characteristics and c-axis anisotropy are considered. To evaluate the effect of the superconducting film shield, an external magnetic field which is supposed to be a magnetic noise is applied. From the simulation results, the time transition of the magnetic flux penetrating the SQUID ring is investigated and the effect of the superconducting film shield is confirmed. The amplitude of the magnetic flux penetrating the SQUID ring can be reduced to about one-sixth since the superconducting film shield prevents the magnetic noise from directly penetrating the SQUID ring.

  2. Optimal statistic for detecting gravitational wave signals from binary inspirals with LISA

    CERN Document Server

    Rogan, A

    2004-01-01

    A binary compact object early in its inspiral phase will be picked up by its nearly monochromatic gravitational radiation by LISA. But even this innocuous appearing candidate poses interesting detection challenges. The data that will be scanned for such sources will be a set of three functions of LISA's twelve data streams obtained through time-delay interferometry, which is necessary to cancel the noise contributions from laser-frequency fluctuations and optical-bench motions to these data streams. We call these three functions pseudo-detectors. The sensitivity of any pseudo-detector to a given sky position is a function of LISA's orbital position. Moreover, at a given point in LISA's orbit, each pseudo-detector has a different sensitivity to the same sky position. In this work, we obtain the optimal statistic for detecting gravitational wave signals, such as from compact binaries early in their inspiral stage, in LISA data. We also present how the sensitivity of LISA, defined by this optimal statistic, vari...

  3. Constraining stellar binary black hole formation scenarios with eLISA eccentricity measurements

    Science.gov (United States)

    Nishizawa, Atsushi; Sesana, Alberto; Berti, Emanuele; Klein, Antoine

    2017-03-01

    A space-based interferometer such as the evolved Laser Interferometer Space Antenna (eLISA) could observe a few to a few thousands of progenitors of black hole binaries (BHBs) similar to those recently detected by Advanced LIGO. Gravitational radiation circularizes the orbit during inspiral, but some BHBs retain a measurable eccentricity at the low frequencies where eLISA is the most sensitive. The eccentricity of a BHB carries precious information about its formation channel: BHBs formed in the field, in globular clusters, or close to a massive black hole (MBH) have distinct eccentricity distributions in the eLISA band. We generate mock eLISA observations, folding in measurement errors, and using a Bayesian model selection, we study whether eLISA measurements can identify the BHB formation channel. We find that a handful of observations would suffice to tell whether BHBs were formed in the gravitational field of an MBH. Conversely, several tens of observations are needed to tell apart field formation from globular cluster formation. A 5-yr eLISA mission with the longest possible armlength is desirable to shed light on BHB formation scenarios.

  4. Robot-arm-based mobile HTS SQUID system for NDE of structures

    Energy Technology Data Exchange (ETDEWEB)

    Yotsugi, K; Hatsukade, Y; Tanaka, S [Department of Ecological Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka, Tenpaku-cho, Toyohashi, Aichi 441-8580 (Japan)], E-mail: hatukade@eco.tut.ac.jp

    2008-02-01

    A robot-arm-based mobile HTS SQUID system was developed for NDE of fixed targets. To realize the system, active magnetic shielding technique using fluxgate as reference sensor for ambient field was applied to a cryocooler-based HTS SQUID gradiometer that was mounted on commercial robot-arm. In this technique, ambient field noise and pulse noise of 550 nT from robot were measured by the fluxgate near the SQUID, and then the fluxgate output was negatively fed back to generate compensation field around the SQUID and fluxgate. The noise from robot was reduced by a factor of about 20 and the shielding technique enabled the HTS SQUID to move in unshielded environment by the robot-arm without flux-trapping or unlocking at 10 mm/s. System noise measurement and inspection of hidden cracks in multi-layer composite-metal structure were demonstrated using the mobile SQUID-NDE system.

  5. Design consideration for dc SQUIDs fabricated in deep sub-micron technology

    International Nuclear Information System (INIS)

    Ketchen, M.B.

    1991-01-01

    Design rules for scaling dc SQUID junctions to optimize SQUID performance have been well known for over a decade, and verified down to the sub-micron regime. Practical SQUIDs having well coupled input coils of usable inductance have generally been fabricated at the 2-5 μm level of lithography. Other technologies, silicon in particular, are now routinely practiced at the 0.5 μm level of lithography with impressive demonstrations at the 0.1-0.25 μm level not uncommon. In this paper the implications of applying such fabrication capability to advance dc SQUID technology are explored. In particular the issues of scaling practical dc SQUIDs down to the 0.1-0.25 μm regime are examined, using as a prototype design the basic washer SQUID with a spiral input coil

  6. Two-stage SQUID systems and transducers development for MiniGRAIL

    International Nuclear Information System (INIS)

    Gottardi, L; Podt, M; Bassan, M; Flokstra, J; Karbalai-Sadegh, A; Minenkov, Y; Reinke, W; Shumack, A; Srinivas, S; Waard, A de; Frossati, G

    2004-01-01

    We present measurements on a two-stage SQUID system based on a dc-SQUID as a sensor and a DROS as an amplifier. We measured the intrinsic noise of the dc-SQUID at 4.2 K. A new dc-SQUID has been fabricated. It was specially designed to be used with MiniGRAIL transducers. Cooling fins have been added in order to improve the cooling of the SQUID and the design is optimized to achieve the quantum limit of the sensor SQUID at temperatures above 100 mK. In this paper we also report the effect of the deposition of a Nb film on the quality factor of a small mass Al5056 resonator. Finally, the results of Q-factor measurements on a capacitive transducer for the current MiniGRAIL run are presented

  7. A SQUID gradiometer module with wire-wound pickup antenna and integrated voltage feedback circuit

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Guofeng [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences (CAS), Shanghai 200050 (China); Peter Gruenberg Institute (PGI-8), Forschungszentrum Juelich (FZJ), D-52425 Juelich (Germany); Joint Research Laboratory on Superconductivity and Bioelectronics, Collaboration between CAS-Shanghai and FZJ, Shanghai 200050 (China); Graduate University of the Chinese Academy of Sciences, Beijing 100049 (China); Zhang, Yi, E-mail: y.zhang@fz-juelich.de [Peter Gruenberg Institute (PGI-8), Forschungszentrum Juelich (FZJ), D-52425 Juelich (Germany); Joint Research Laboratory on Superconductivity and Bioelectronics, Collaboration between CAS-Shanghai and FZJ, Shanghai 200050 (China); Zhang Shulin [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences (CAS), Shanghai 200050 (China); Joint Research Laboratory on Superconductivity and Bioelectronics, Collaboration between CAS-Shanghai and FZJ, Shanghai 200050 (China); Krause, Hans-Joachim [Peter Gruenberg Institute (PGI-8), Forschungszentrum Juelich (FZJ), D-52425 Juelich (Germany); Joint Research Laboratory on Superconductivity and Bioelectronics, Collaboration between CAS-Shanghai and FZJ, Shanghai 200050 (China); and others

    2012-10-15

    The performance of the direct readout schemes for dc SQUID, Additional Positive Feedback (APF), noise cancellation (NC) and SQUID bootstrap circuit (SBC), have been studied in conjunction with planar SQUID magnetometers. In this paper, we examine the NC technique applied to a niobium SQUID gradiometer module with an Nb wire-wound antenna connecting to a dual-loop SQUID chip with an integrated voltage feedback circuit for suppression of the preamplifier noise contribution. The sensitivity of the SQUID gradiometer module is measured to be about 1 fT/(cm {radical}Hz) in the white noise range in a magnetically shielded room. Using such gradiometer, both MCG and MEG signals are recorded.

  8. A three-axis SQUID-based absolute vector magnetometer

    Energy Technology Data Exchange (ETDEWEB)

    Schönau, T.; Schmelz, M.; Stolz, R.; Anders, S.; Linzen, S.; Meyer, H.-G. [Department of Quantum Detection, Leibniz Institute of Photonic Technology, Jena 07745 (Germany); Zakosarenko, V.; Meyer, M. [Supracon AG, An der Lehmgrube 11, Jena 07751 (Germany)

    2015-10-15

    We report on the development of a three-axis absolute vector magnetometer suited for mobile operation in the Earth’s magnetic field. It is based on low critical temperature dc superconducting quantum interference devices (LTS dc SQUIDs) with sub-micrometer sized cross-type Josephson junctions and exhibits a white noise level of about 10 fT/Hz{sup 1/2}. The width of superconducting strip lines is restricted to less than 6 μm in order to avoid flux trapping during cool-down in magnetically unshielded environment. The long-term stability of the flux-to-voltage transfer coefficients of the SQUID electronics is investigated in detail and a method is presented to significantly increase their reproducibility. We further demonstrate the long-term operation of the setup in a magnetic field varying by about 200 μT amplitude without the need for recalibration.

  9. The squid-Vibrio symbioses: from demes to genes.

    Science.gov (United States)

    Kimbell, Jennifer R; McFall-Ngai, Margaret J

    2003-04-01

    The monospecific light organ association between the Hawaiian sepiolid squid Euprymna scolopes and the marine luminous bacterium Vibrio fischeri has been used as a model for the study of the most common type of coevolved animal-bacterial interaction; i.e., the association of Gram-negative bacteria with the extracellular apical surfaces of polarized epithelia. Analysis of the squid-vibrio symbiosis has ranged from characterizations of the harvesting mechanisms by which the host ensures colonization by the appropriate symbiont to identification of bacteria-induced changes in host gene expression that accompany the establishment and maintenance of the relationship. Studies of this model have been enhanced by extensive collaboration with microbiologists, who are able to manipulate the genetics of the bacterial symbiont. The results of our studies have indicated that initiation and persistence of the association requires a complex, reciprocal molecular dialogue between these two phylogenetically distant partners.

  10. On-site detection of packaged squid freshness

    Science.gov (United States)

    Ahmad, Noor Azizah; Heng, Lee Yook; Salam, Faridah; Hanifah, Sharina Abu

    2018-04-01

    The development of indicator label for detection of total volatile basic nitrogen (TVB-N) is described. Dye extract from edible plants containing anthocyanins was immobilized onto iota-carrageenan as polymer matrix. TVB-N detection worked based on pH increase as the basic deterioration volatile amines generated in the package headspace. Results showed that the indicator label has changed color from blue to green after 12 hours of storage at ambient conditions. The TVB-N value was 38.9648 mg /100 g which is exceeded of acceptability level for seafood products. The pH value of squid flesh has also increased during storage. The colour values of L * and a * negative increases while b* negative decrease with increasing storage time. The indicator label is potentially used as freshness indicator for squid at ambient conditions.

  11. Magnetic evaluation of a solar panel using HTS-SQUID

    Energy Technology Data Exchange (ETDEWEB)

    Kiwa, Toshihiko, E-mail: kiwa@okayama-u.ac.jp; Fukudome, Yohei; Miyazaki, Shingo; Saari, Mohd Mawardi; Sakai, Kenji; Tsukada, Keiji

    2013-11-15

    Highlights: •The magnetic evaluation system of a solar panel using HTS-SQUID has been developed. •The electric circuits made by the discrete devices on the circuit board were visualized. •The electric properties of the commercial solar panels were demonstrated. -- Abstract: The magnetic evaluation system of a solar panel using HTS-SQUID has been proposed and developed. A normal pick-up coil was applied to detect the tangential magnetic field to the panel surface. Since the detected field could be related to the currents of the solar panels, the electric properties of the solar panels could be evaluated. In this work, the evaluation of the electric properties of the commercial solar panels as well as the electric circuits made by the discrete devices on the circuit board was visualized.

  12. Magnetic evaluation of a solar panel using HTS-SQUID

    International Nuclear Information System (INIS)

    Kiwa, Toshihiko; Fukudome, Yohei; Miyazaki, Shingo; Saari, Mohd Mawardi; Sakai, Kenji; Tsukada, Keiji

    2013-01-01

    Highlights: •The magnetic evaluation system of a solar panel using HTS-SQUID has been developed. •The electric circuits made by the discrete devices on the circuit board were visualized. •The electric properties of the commercial solar panels were demonstrated. -- Abstract: The magnetic evaluation system of a solar panel using HTS-SQUID has been proposed and developed. A normal pick-up coil was applied to detect the tangential magnetic field to the panel surface. Since the detected field could be related to the currents of the solar panels, the electric properties of the solar panels could be evaluated. In this work, the evaluation of the electric properties of the commercial solar panels as well as the electric circuits made by the discrete devices on the circuit board was visualized

  13. Size increment of jumbo flying squid Dosidicus gigas mature females in Peruvian waters, 1989-2004

    Science.gov (United States)

    Argüelles, Juan; Tafur, Ricardo; Taipe, Anatolio; Villegas, Piero; Keyl, Friedeman; Dominguez, Noel; Salazar, Martín

    2008-10-01

    Changes in population structure of the jumbo flying squid Dosidicus gigas in Peruvian waters were studied based on size-at-maturity from 1989 to 2004. From 1989 to 1999, mature squid belonging to the medium-sized group prevailed, but from 2001 on, mature squids were larger. This change is not related to the changes in sea surface temperature and we hypothesized that it was caused by the population increase of mesopelagic fishes as prey.

  14. Absolute calibration and beam background of the Squid Polarimeter

    International Nuclear Information System (INIS)

    Blaskiewicz, M.M.; Cameron, P.R.; Shea, T.J.

    1996-01-01

    The problem of beam background in Squid Polarimetry is not without residual benefits. The authors may deliberately generate beam background by gently kicking the beam at the spin tune frequency. This signal may be used to accomplish a simple and accurate absolute calibration of the polarimeter. The authors present details of beam background calculations and their application to polarimeter calibration, and suggest a simple proof-of-principle accelerator experiment

  15. Symplectin evolved from multiple duplications in bioluminescent squid

    DEFF Research Database (Denmark)

    Francis, Warren R.; Christianson, Lynne M.; Haddock, Steven H.D.

    2017-01-01

    The squid Sthenoteuthis oualaniensis, formerly Symplectoteuthis oualaniensis, generates light using the luciferin coelenterazine and a unique enzyme, symplectin. Genetic information is limited for bioluminescent cephalopod species, so many proteins, including symplectin, occur in public databases...... functioning is conserved across essentially all members of the protein family, even those unlikely to be used for bioluminescence. Conversely, active site residues involved in pantetheinase catalysis are also conserved across essentially all of these proteins, suggesting that symplectin may have multiple...

  16. Antibacterial Activity of Melanin from Cuttlefish and Squid Ink

    OpenAIRE

    Yuspihana Fitrial; Iin Khusnul Khotimah

    2017-01-01

    Marine environment comprises of many organism which are known to posses bioactive compound as a common means of self-defense or for the protection of eggs and embryos. Class Cephalopods (such as squidand cuttlefish) are notable for their defences, such as jetting escape movements, changes in colouration, toxic venom and inking.This study aims to compare the antibacterial activity of melanin from cuttlefish ink (Sepia sp.) with squid ink (Loligo sp.) against E. coli. Extraction and purificatio...

  17. Detecting damage in steel with scanning SQUID microscopy

    International Nuclear Information System (INIS)

    Lee, Tae-Kyu; Clatterbuck, D.M.; Morris, J.W. Jr.; Shaw, T.J.; Lee, Seungkyun; Clarke, John

    2002-01-01

    A 'Holy Grail' of NDE research is a non-destructive method for measuring fatigue damage prior to crack initiation. High-Tc scanning SQUID microscopy may be a useful tool. Because of the exceptional magnetic sensitivity of this technique, fatigue damage can be detected well before microcrack initiation, and in the absence of other obvious microstructure or property changes. Given the spatial resolution of the technique, undamaged material can be located and used to set internal standards

  18. Detecting damage in steel with scanning SQUID microscopy

    International Nuclear Information System (INIS)

    Lee, Tae-Kyu; Clatterbuck, David; Morris Jr., J.W.; Shaw, T.J.; McDermott R.; Clarke, John

    2001-01-01

    A ''Holy Grail'' of NDE research is a non-destructive method for measuring fatigue damage prior to crack initiation. High-Tc scanning SQUID microscopy may be a useful tool. Because of the exceptional magnetic sensitivity of this technique, fatigue damage can be detected well before microcrack initiation, and in the absence of other obvious microstructure or property changes. Given the spatial resolution of the technique, undamaged material can be located and used to set internal standards

  19. SQUID sensor application for small metallic particle detection

    International Nuclear Information System (INIS)

    Tanaka, Saburo; Hatsukade, Yoshimi; Ohtani, Takeyoshi; Suzuki, Shuichi

    2009-01-01

    High-Tc superconducting quantum interference device (SQUID) is an ultra-sensitive magnetic sensor. Since the performance of the SQUID is improved and stabilized, now it is ready for application. One strong candidate for application is a detection system of magnetic foreign matters in industrial products or beverages. There is a possibility that ultra-small metallic foreign matter has been accidentally mixed with industrial products such as lithium ion batteries. If this happens, the manufacturer of the product suffers a great loss recalling products. The outer dimension of metallic particles less than 100 μm cannot be detected by an X-ray imaging, which is commonly used for the inspection. Ionization of the material is also a big issue for beverages in the case of the X-ray imaging. Therefore a highly sensitive and safety detection system for small foreign matters is required. We developed detection systems based on high-Tc SQUID with a high-performance magnetic shield. We could successfully measure small iron particles of 100 μm on a belt conveyer and stainless steel balls of 300 μm in water. These detection levels were hard to be achieved by a conventional X-ray detection or other methods

  20. Simulation and optimization of a dc SQUID with finite capacitance

    Energy Technology Data Exchange (ETDEWEB)

    de Waal, V.J.; Schrijner, P.; Llurba, R.

    1984-02-01

    This paper deals with the calculations of the noise an the optimization of the energy resolution of a dc SQUID with finite junction capacitance. Up to now noise calculations of dc SQUIDs were performed using a model without parasitic capacitances across the Josephson junctions. As the capacitances limit the performance of the SQUID, for a good optimization one must take them into account. The model consists of two coupled nonlinear second-order differential equations. The equations are very suitable for simulation with an analog circuit. We implemented the model on a hybrid computer. The noise spectrum from the model is calculated with a fast Fourier transform. A calculation of the energy resolution for one set of parameters takes about 6 min of computer time. Detailed results of the optimization are given for products of inductance and temperature of LT = 1.2 and 5 nHK. Within a range of ..beta.. and ..beta../sub c/ between 1 and 2, which is optimum, the energy resolution is nearly independent of these variables. In this region the energy resolution is near the value calculated without parasitic capacitances. Results of the optimized energy resolution are given as a function of LT between 1.2 and 10 nHK.

  1. Simulation and optimization of a dc SQUID with finite capacitance

    Science.gov (United States)

    de Waal, V. J.; Schrijner, P.; Llurba, R.

    1984-02-01

    This paper deals with the calculations of the noise and the optimization of the energy resolution of a dc SQUID with finite junction capacitance. Up to now noise calculations of dc SQUIDs were performed using a model without parasitic capacitances across the Josephson junctions. As the capacitances limit the performance of the SQUID, for a good optimization one must take them into account. The model consists of two coupled nonlinear second-order differential equations. The equations are very suitable for simulation with an analog circuit. We implemented the model on a hybrid computer. The noise spectrum from the model is calculated with a fast Fourier transform. A calculation of the energy resolution for one set of parameters takes about 6 min of computer time. Detailed results of the optimization are given for products of inductance and temperature of LT=1.2 and 5 nH K. Within a range of β and β c between 1 and 2, which is optimum, the energy resolution is nearly independent of these variables. In this region the energy resolution is near the value calculated without parasitic capacitances. Results of the optimized energy resolution are given as a function of LT between 1.2 and 10 mH K.

  2. Transfer of 60Co from midwater squid to sperm whales

    International Nuclear Information System (INIS)

    Umezu, Takeshi; Minamisako, Yoko; Ebihara, Hiroshi; Watanabe, Hiroshi.

    1984-01-01

    Sperm whales are notable squid-eaters. They feed mainly on medium to large-sized cephalopods at midwater levels and defecate near the surface. This suggests the existence of an upward transport of 60 Co by sperm whales from the mesopelagic zone (150-1,200m). To elucidate this squid-whale route for this artificial radionuclide, 60 Co content was determined in squid and in predator whales captured by commercial whaling. In the Cephalopoda livers 60 Co levels of 30-500 mBq kg -1 wet were found and in the viscera of Odontoceti (toothed whales) 15-40 mBq kg -1 wet. About 0.3% of 60 Co ingested was estimated to be retained in a 23-year-old male sperm whale. In the livers of Bryde's whales, 60 Co levels of 40-80 mBq kg -1 wet were detected, but not in euphausiids and sardines, their possible prey. The level of Co in sperm whales was nearly the same as in Bryde's whales. Specific radioactivity 60 Co/ 59 Co in mBq μg -1 was several times higher in sperm whale (1.1-1.6) than in cephalopods (0.19-0.77). Eating prey with a high content of 60 Co in the 1960's may have contributed to the present body burden in sperm whales with a long-life span. However, the origin of 60 Co in Bryde's whales is unknown. (author)

  3. Thermoelectric SQUID method for the detection of segregations

    Science.gov (United States)

    Hinken, Johann H.; Tavrin, Yury

    2000-05-01

    Aero engine turbine discs are most critical parts. Material inhomogeneities can cause disc fractures during the flight with fatal air disasters. Nondestructive testing (NDT) of the discs in various machining steps is necessary and performed as well as possible. Conventional NDT methods, however, like eddy current testing and ultrasonic testing have unacceptable limits. For example, subsurface segregations often cannot be detected directly but only indirectly in such cases when cracks already have developed from them. This may be too late. A new NDT method, which we call the Thermoelectric SQUID Method, has been developed. It allows for the detection of metallic inclusions within non-ferromagnetic metallic base material. This paper describes the results of a feasibility study on aero engine turbine discs made from Inconel® 718. These contained segregations that had been detected before by anodic etching. With the Thermoelectric SQUID Method, these segregations were detected again, and further segregations below the surfaces have been found, which had not been detected before. For this new NDT method the disc material is quasi-transparent. The Thermoelectric SQUID Method is also useful to detect distributed and localized inhomogeneities in pure metals like niobium sheets for particle accelerators.

  4. Low-frequency nuclear quadrupole resonance with a dc SQUID

    International Nuclear Information System (INIS)

    Chang, J.W.

    1991-07-01

    Conventional pure nuclear quadrupole resonance (NQR) is a technique well suited for the study of very large quadrupolar interactions. Numerous nuclear magnetic resonance (NMR) techniques have been developed for the study of smaller quadrupolar interactions. However, there are many nuclei which have quadrupolar interactions of intermediate strength. Quadrupolar interactions in this region have traditionally been difficult or unfeasible to detect. This work describes the development and application of a SQUID NQR technique which is capable of measuring intermediate strength quadrupolar interactions, in the range of a few hundred kilohertz to several megahertz. In this technique, a dc SQUID (Superconducting QUantum Interference Device) is used to monitor the longitudinal sample magnetization, as opposed to the transverse magnetization, as a rf field is swept in frequency. This allows the detection of low-frequency nuclear quadrupole resonances over a very wide frequency range with high sensitivity. The theory of this NQR technique is discussed and a description of the dc SQUID system is given. In the following chapters, the spectrometer is discussed along with its application to the study of samples containing half-odd-integer spin quadrupolar nuclei, in particular boron-11 and aluminum-27. The feasibility of applying this NQR technique in the study of samples containing integer spin nuclei is discussed in the last chapter. 140 refs., 46 figs., 6 tabs

  5. SQUID-based noise thermometer for sub-Millikelvin refrigerators

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Marco; Beyer, Joern; Klemm, Monique [Physikalisch-Technische Bundesanstalt, Abbestrasse 2-12, 10587 Berlin (Germany); Alivaliollahi, Sassan; Barthelmess, Henry [Magnicon GmbH, Barkhausenweg 11, 22339 Hamburg (Germany)

    2015-07-01

    The magnetic field fluctuation thermometer (MFFT) is a high-accuracy SQUID-based noise thermometer suitable for sub-Kelvin thermometry. A highly sensitive low-Tc SQUID magnetometer detects inductively the magnetic field fluctuation above a metal surface. The fluctuations are generated by the thermal activated noise currents inside the metal body that is thermally anchored to the temperature stage to be measured. The spectral shape is independent of temperature as the electrical conductivity is constant and the geometry is fixed. The magnetic noise power spectral amplitudes at any frequencies are directly proportional to temperature. Hence, only one reference measurement at a known temperature is required for calibration. A complete MFFT thermometer system for the temperature range of ca. 4 K down to <10 mK is commercially available. We have now developed an integrated MFFT with an extended range of operation down to <1 mK. For this purpose the sensitivity of the SQUID sensor has been increased, the metal body geometry modified and the magnetic shielding of the MFFT module improved. These modifications make it possible to obtain a thermometer noise temperature of <10 μK. We discuss the rationale for our MFFT configuration and present numerical simulations and experimental results.

  6. Trophic niche of squids: Insights from isotopic data in marine systems worldwide

    Science.gov (United States)

    Navarro, Joan; Coll, Marta; Somes, Christoper J.; Olson, Robert J.

    2013-10-01

    Cephalopods are an important prey resource for fishes, seabirds, and marine mammals, and are also voracious predators on crustaceans, fishes, squid and zooplankton. Because of their high feeding rates and abundance, squids have the potential to exert control on the recruitment of commercially important fishes. In this review, we synthesize the available information for two intrinsic markers (δ15N and δ13C isotopic values) in squids for all oceans and several types of ecosystems to obtain a global view of the trophic niches of squids in marine ecosystems. In particular, we aimed to examine whether the trophic positions and trophic widths of squid species vary among oceans and ecosystem types. To correctly compare across systems, we adjusted squid δ15N values for the isotopic variability of phytoplankton at the base of the food web provided by an ocean circulation-biogeochemistry-isotope model. Studies that focused on the trophic ecology of squids using isotopic techniques were few, and most of the information on squids was from studies on their predators. Our results showed that squids occupy a large range of trophic positions and exploit a large range of trophic resources, reflecting the versatility of their feeding behavior and confirming conclusions from food-web models. Clear differences in both trophic position and trophic width were found among oceans and ecosystem types. The study also reinforces the importance of considering the natural variation in isotopic values when comparing the isotopic values of consumers inhabiting different ecosystems.

  7. Quantitative analysis of LISA pathfinder test-mass noise

    International Nuclear Information System (INIS)

    Ferraioli, Luigi; Congedo, Giuseppe; Hueller, Mauro; Vitale, Stefano; Hewitson, Martin; Nofrarias, Miquel; Armano, Michele

    2011-01-01

    LISA Pathfinder (LPF) is a mission aiming to test the critical technology for the forthcoming space-based gravitational-wave detectors. The main scientific objective of the LPF mission is to demonstrate test masses free falling with residual accelerations below 3x10 -14 m s -2 /√(Hz) at 1 mHz. Reaching such an ambitious target will require a significant amount of system optimization and characterization, which will in turn require accurate and quantitative noise analysis procedures. In this paper, we discuss two main problems associated with the analysis of the data from LPF: i) excess noise detection and ii) noise parameter identification. The mission is focused on the low-frequency region ([0.1, 10] mHz) of the available signal spectrum. In such a region, the signal is dominated by the force noise acting on test masses. At the same time, the mission duration is limited to 90 days and typical data segments will be 24 hours in length. Considering those constraints, noise analysis is expected to deal with a limited amount of non-Gaussian data, since the spectrum statistics will be far from Gaussian and the lowest available frequency is limited by the data length. In this paper, we analyze the details of the expected statistics for spectral data and develop two suitable excess noise estimators. One is based on the statistical properties of the integrated spectrum, the other is based on the Kolmogorov-Smirnov test. The sensitivity of the estimators is discussed theoretically for independent data, then the algorithms are tested on LPF synthetic data. The test on realistic LPF data allows the effect of spectral data correlations on the efficiency of the different noise excess estimators to be highlighted. It also reveals the versatility of the Kolmogorov-Smirnov approach, which can be adapted to provide reasonable results on correlated data from a modified version of the standard equations for the inversion of the test statistic. Closely related to excess noise

  8. Nanobridge SQUIDs as calorimetric inductive particle detectors

    International Nuclear Information System (INIS)

    Gallop, John; Cox, David; Hao, Ling

    2015-01-01

    Superconducting transition edge sensors (TESs) have made dramatic progress since their invention some 65 years ago (Andrews et al 1949 Phys. Rev. 76 154–155; Irwin and Hilton 2005 Topics Appl. Phys. 99 63–149) until now there are major imaging arrays of TESs with as many as 7588 separate sensors. These are extensively used by astronomers for some ground-breaking observations (Hattori et al 2013 Nucl. Instrum. Methods Phys. Res. A 732 299–302). The great success of TES systems has tended to overshadow other superconducting sensor developments. However there are other types (Sobolewski et al 2003 IEEE Trans. Appl. Supercond. 13 1151–7; Hadfield 2009 Nat. Photonics 3 696–705) which are discussed in papers within this special edition of the journal. Here we describe a quite different type of detector, also applicable to single photon detection but possessing possible advantages (higher sensitivity, higher operating temperature) over the conventional TES, at least for single detectors. (paper)

  9. Verification of time-delay interferometry techniques using the University of Florida LISA interferometry simulator

    Energy Technology Data Exchange (ETDEWEB)

    Mitryk, Shawn J; Wand, Vinzenz; Mueller, Guido, E-mail: smitryk@phys.ufl.ed, E-mail: mueller@phys.ufl.ed [Department of Physics, University of Florida, PO Box 118440, Gainesville, FL 32611-8440 (United States)

    2010-04-21

    Laser Interferometer Space Antenna (LISA) is a cooperative NASA/ESA mission proposed to directly measure gravitational waves (GW) in the frequency range from 30 muHz to 1 Hz with an optimal strain sensitivity of 10{sup -21}/sq root(Hz) at 3 mHz. LISA will utilize a modified Michelson interferometer to measure length changes of 40 pm/sq root(Hz) between drag-free proof masses located on three separate spacecraft (SC) separated by a distance of 5 Gm. The University of Florida has developed a hardware-in-the-loop simulator of the LISA constellation to verify the laser noise cancellation technique known as time-delay interferometry (TDI). We replicate the frequency stabilization of the laser on the local SC and the phase-locking of the lasers on the far SC. The laser photodetector beatnotes are electronically delayed, Doppler shifted and applied with a mock GW signal to simulate the laser link between the SC. The beatnotes are also measured with a LISA-like phasemeter and the data are used to extract the laser phase and residual phase-lock loop noise in post-processing through TDI. This uncovers the GW modulation signal buried under the laser noise. The results are then compared to the requirements defined by the LISA science collaboration.

  10. LISA Pathfinder test-mass charging during galactic cosmic-ray flux short-term variations

    Science.gov (United States)

    Grimani, C.; Fabi, M.; Lobo, A.; Mateos, I.; Telloni, D.

    2015-02-01

    Metal free-floating test masses aboard the future interferometers devoted to gravitational wave detection in space are charged by galactic and solar cosmic rays with energies \\gt 100 MeV/n. This process represents one of the main sources of noise in the lowest frequency band (\\lt 10-3 Hz) of these experiments. We study here the charging of the LISA Pathfinder (LISA-PF) gold-platinum test masses due to galactic cosmic-ray (GCR) protons and helium nuclei with the Fluka Monte Carlo toolkit. Projections of the energy spectra of GCRs during the LISA-PF operations in 2015 are considered. This work was carried out on the basis of the solar activity level and solar polarity epoch expected for LISA-PF. The effects of GCR short-term variations are evaluated here for the first time. Classical Forbush decreases, GCR variations induced by the Sun rotation, and fluctuations in the LISA-PF frequency bandwidth are discussed.

  11. Sensing and actuation system for the University of Florida Torsion Pendulum for LISA

    Science.gov (United States)

    Chilton, Andrew; Shelley, Ryan; Olatunde, Taiwo; Ciani, Giacomo; Conklin, John; Mueller, Guido

    2014-03-01

    Space-based gravitational wave detectors like LISA are a necessity for understanding the low-frequency portion of the gravitational universe. They use test masses (TMs) which are separated by Gm and are in free fall inside their respective spacecraft. Their relative distance is monitored with laser interferometry at the pm/rtHz level in the LISA band, ranging from 0.1 to 100 mHz. Each TM is enclosed in a housing that provides isolation, capacitive sensing, and electrostatic actuation capabilities. The electronics must both be sensitive at the 1 nm/rtHz level and not induce residual acceleration noise above the requirement for LISA Pathfinder (3*10-15 m/sec2Hz1/2at 3 mHz). Testing and developing this technology is one of the roles of the University of Florida Torsion Pendulum, the only US testbed for LISA-like gravitational reference sensor technology. Our implementation of the sensing system functions by biasing our hollow LISA-like TMs with a 100 kHz sine wave and coupling a pair surrounding electrodes as capacitors to a pair of preamps and a differential amplifier; all other processing is done digitally. Here we report on the design of, implementation of, and preliminary results from the UF Torsion Pendulum.

  12. Reducing tilt-to-length coupling for the LISA test mass interferometer

    Science.gov (United States)

    Tröbs, M.; Schuster, S.; Lieser, M.; Zwetz, M.; Chwalla, M.; Danzmann, K.; Fernández Barránco, G.; Fitzsimons, E. D.; Gerberding, O.; Heinzel, G.; Killow, C. J.; Perreur-Lloyd, M.; Robertson, D. I.; Schwarze, T. S.; Wanner, G.; Ward, H.

    2018-05-01

    Objects sensed by laser interferometers are usually not stable in position or orientation. This angular instability can lead to a coupling of angular tilt to apparent longitudinal displacement—tilt-to-length coupling (TTL). In LISA this is a potential noise source for both the test mass interferometer and the long-arm interferometer. We have experimentally investigated TTL coupling in a setup representative for the LISA test mass interferometer and used this system to characterise two different imaging systems (a two-lens design and a four-lens design) both designed to minimise TTL coupling. We show that both imaging systems meet the LISA requirement of  ±25 μm rad‑1 for interfering beams with relative angles of up to  ±300 μrad. Furthermore, we found a dependency of the TTL coupling on beam properties such as the waist size and location, which we characterised both theoretically and experimentally.

  13. In-flight thermal experiments for LISA Pathfinder: Simulating temperature noise at the Inertial Sensors

    International Nuclear Information System (INIS)

    Armano, M; Audley, H; Born, M; Danzmann, K; Diepholz, I; Auger, G; Binetruy, P; Baird, J; Bortoluzzi, D; Brandt, N; Fitzsimons, E; Bursi, A; Caleno, M; Cavalleri, A; Cesarini, A; Dolesi, R; Ferroni, V; Cruise, M; Dunbar, N; Ferraioli, L

    2015-01-01

    Thermal Diagnostics experiments to be carried out on board LISA Pathfinder (LPF) will yield a detailed characterisation of how temperature fluctuations affect the LTP (LISA Technology Package) instrument performance, a crucial information for future space based gravitational wave detectors as the proposed eLISA. Amongst them, the study of temperature gradient fluctuations around the test masses of the Inertial Sensors will provide as well information regarding the contribution of the Brownian noise, which is expected to limit the LTP sensitivity at frequencies close to 1 mHz during some LTP experiments. In this paper we report on how these kind of Thermal Diagnostics experiments were simulated in the last LPF Simulation Campaign (November, 2013) involving all the LPF Data Analysis team and using an end-to-end simulator of the whole spacecraft. Such simulation campaign was conducted under the framework of the preparation for LPF operations. (paper)

  14. The Mock LISA Data Challenges: from challenge 3 to challenge 4

    International Nuclear Information System (INIS)

    Babak, Stanislav; Petiteau, Antoine; Robinson, Emma L; Baker, John G; McWilliams, Sean T; Arnaud, Keith A; Benacquista, Matthew J; Cornish, Neil J; Adams, Matt; Larson, Shane L; Mandel, Ilya; Porter, Edward K; Vallisneri, Michele; Cutler, Curt; Vecchio, Alberto; Blaut, Arkadiusz; Bridges, Michael; Feroz, Farhan; Cohen, Michael; Gair, Jonathan R.

    2010-01-01

    The Mock LISA Data Challenges are a program to demonstrate LISA data-analysis capabilities and to encourage their development. Each round of challenges consists of one or more datasets containing simulated instrument noise and gravitational waves from sources of undisclosed parameters. Participants analyze the datasets and report best-fit solutions for the source parameters. Here we present the results of the third challenge, issued in April 2008, which demonstrated the positive recovery of signals from chirping galactic binaries, from spinning supermassive-black-hole binaries (with optimal SNRs between ∼10 and 2000), from simultaneous extreme-mass-ratio inspirals (SNRs of 10-50), from cosmic-string-cusp bursts (SNRs of 10-100), and from a relatively loud isotropic background with Ω gw (f) ∼ 10 -11 , slightly below the LISA instrument noise.

  15. The Mock LISA Data Challenges: from challenge 3 to challenge 4

    Energy Technology Data Exchange (ETDEWEB)

    Babak, Stanislav; Petiteau, Antoine; Robinson, Emma L [Max-Planck-Institut fuer Gravitationsphysik (Albert-Einstein-Institut), Am Muehlenberg 1, D-14476 Golm bei Potsdam (Germany); Baker, John G; McWilliams, Sean T; Arnaud, Keith A [Gravitational Astrophysics Laboratory, NASA Goddard Space Flight Center, 8800 Greenbelt Rd, Greenbelt, MD 20771 (United States); Benacquista, Matthew J [Center for Gravitational Wave Astronomy, University of Texas at Brownsville, Brownsville, TX 78520 (United States); Cornish, Neil J; Adams, Matt [Department of Physics, Montana State University, Bozeman, MT 59717 (United States); Larson, Shane L [Department of Physics, Utah State University, Logan, UT 84322 (United States); Mandel, Ilya [Department of Physics and Astronomy, Northwestern University, Evanston, IL (United States); Porter, Edward K [APC, UMR 7164, University Paris 7 Denis Diderot, 10, rue Alice Domon et Leonie Duquet, 75025 Paris Cedex 13 (France); Vallisneri, Michele; Cutler, Curt [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Vecchio, Alberto [School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B152TT (United Kingdom); Blaut, Arkadiusz [Institute of Theoretical Physics, University of Wroclaw, Wroclaw (Poland); Bridges, Michael; Feroz, Farhan [Astrophysics Group, Cavendish Laboratory, University of Cambridge, Cambridge CB30HE (United Kingdom); Cohen, Michael [Theoretical Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Gair, Jonathan R., E-mail: Michele.Vallisneri@jpl.nasa.go [Institute of Astronomy, University of Cambridge, Cambridge CB30HA (United Kingdom)

    2010-04-21

    The Mock LISA Data Challenges are a program to demonstrate LISA data-analysis capabilities and to encourage their development. Each round of challenges consists of one or more datasets containing simulated instrument noise and gravitational waves from sources of undisclosed parameters. Participants analyze the datasets and report best-fit solutions for the source parameters. Here we present the results of the third challenge, issued in April 2008, which demonstrated the positive recovery of signals from chirping galactic binaries, from spinning supermassive-black-hole binaries (with optimal SNRs between approx10 and 2000), from simultaneous extreme-mass-ratio inspirals (SNRs of 10-50), from cosmic-string-cusp bursts (SNRs of 10-100), and from a relatively loud isotropic background with OMEGA{sub gw}(f) approx 10{sup -11}, slightly below the LISA instrument noise.

  16. LISA technologies in new light: exploring alternatives for charge management and optical bench construction

    Science.gov (United States)

    Ciani, Giacomo; Chilton, Andrew; Olatunde, Taiwo; Apple, Stephen; Conklin, John W.; Mueller, Guido

    2015-08-01

    A LISA-like gravitational wave observatory is the choice candidate for ESA's L3 large mission scheduled to launch in 2034. The LISA Test Package (LTP) mission will launch later this year and test many critical technologies needed for such an observatory, among which are picometer interferometry in space and UV charge management of the Test Mass (TM). The design of these subsystems has been frozen many years ago during the final formulation of the LTP mission; since then, the LISA mission concept has evolved and new technologies have become available, making it possible to re-think the way these subsystem are implemented. With the final formulation of the L3 mission still years in the future and the LTP results expected in about one year, now is an ideal time look for areas of possible improvement and explore alternative implementations that can enhance performance, reduce costs or mitigate risks.Recently developed UV LED are lighter, cheaper and more powerful than traditional mercury lamps; in addition, their fast response time can be used to implement AC discharge techniques that can save even more space and power, and provide a more precise control of the charge.The most recent iteration of the mission baseline design allows for eliminating some of the optical components initially deemed essential; paired with the use of polarization multiplexing, this permits a redesign of the optical bench that simplifies the layout and enables a modular approach to machining and assembly, thus reducing the risks and costs associated with the current monolithic design without compromising the picometer stability of the optical path.Leveraging on extensive previous experience with LISA interferometry and the availability of a torsion pendulum-based LISA test-bed, the University of Florida LISA group is working at developing, demonstrating and optimizing both these technologies. I will describe the most recent advancements and results.

  17. 76 FR 68642 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Science.gov (United States)

    2011-11-07

    ... update to essential fish habitat designations for all life stages of mackerel, longfin squid, Illex squid... issued a mackerel permit may not fish for, possess, or land more than 20,000 lb (9.08 mt) of mackerel per trip, and that, during any closure that occurs after June 1, vessels may not fish for, possess, or land...

  18. LTP - LISA technology package: Development challenges of a spaceborne fundamental physics experiment

    International Nuclear Information System (INIS)

    Gerndt, R

    2009-01-01

    The LISA Technology Package (LTP) is the main payload onboard the LISA Pathfinder Spacecraft. The LTP Instrument together with the Drag-Free Attitude Control System (DFACS) and the respective LTP and DFACS operational software forms the LTP Experiment. It is completed by the FEEPs of the LPF spacecraft that are controlled by DFACS in order to control the spacecraft's attitude along with the experiment's needs. This article concentrates on aspects of the Industrial development of the LTP Instrument items and on essential performance issues of LTP. Examples of investigations on specific issue will highlight the kind of special problems to be solved for LTP in close cooperation with the Scientific Community.

  19. Acoustic waves and the detectability of first-order phase transitions by eLISA

    Science.gov (United States)

    Weir, David J.

    2017-05-01

    In various extensions of the Standard Model it is possible that the electroweak phase transition was first order. This would have been a violent process, involving the formation of bubbles and associated shock waves. Not only would the collision of these bubbles and shock waves be a detectable source of gravitational waves, but persistent acoustic waves could enhance the signal and improve prospects of detection by eLISA. I summarise the results of a recent campaign to model such a phase transition based on large-scale hydrodynamical simulations, and its implications for the eLISA mission.

  20. From LPF to eLISA: new approach in payload software

    Science.gov (United States)

    Gesa, Ll.; Martin, V.; Conchillo, A.; Ortega, J. A.; Mateos, I.; Torrents, A.; Lopez-Zaragoza, J. P.; Rivas, F.; Lloro, I.; Nofrarias, M.; Sopuerta, CF.

    2017-05-01

    eLISA will be the first observatory in space to explore the Gravitational Universe. It will gather revolutionary information about the dark universe. This implies a robust and reliable embedded control software and hardware working together. With the lessons learnt with the LISA Pathfinder payload software as baseline, we will introduce in this short article the key concepts and new approaches that our group is working on in terms of software: multiprocessor, self-modifying-code strategies, 100% hardware and software monitoring, embedded scripting, Time and Space Partition among others.

  1. Doing Science with eLISA: Astrophysics and Cosmology in the Millihertz Regime

    Science.gov (United States)

    Amaro, Seoane, Pau; Aoudia, Sofiane; Babak, Stanislav; Binetruy, Pierre; Berti, Amanuele; Bohe, Alejandro; Caprini, Chiara; Colpi, Monica; Cornish, Neil J.; Danzmann, Karsten; hide

    2012-01-01

    This document introduces the exciting and fundamentally new science and astronomy that the European New Gravitational Wave Observatory (NGO) mission (derived from the previous LISA proposal) will deliver. The mission (which we will refer to by its informal name eLISA ) will survey for the first time the low-frequency gravitational wave band (about 0.1 mHz to 1 Hz), with sufficient sensitivity to detect interesting individual astrophysical sources out to z = 15. The measurements described here will address the basic scientific goals that have been captured in ESA s New Gravitational Wave Observatory Science Requirements Document ; they are presented here so that the wider scientific community can have access to them. The eLISA mission will discover and study a variety of cosmic events and systems with high sensitivity: coalescences of massive black holes binaries, brought together by galaxy mergers; mergers of earlier, less-massive black holes during the epoch of hierarchical galaxy and black-hole growth; stellar-mass black holes and compact stars in orbits just skimming the horizons of massive black holes in galactic nuclei of the present era; extremely compact white dwarf binaries in our Galaxy, a rich source of information about binary evolution and about future Type Ia supernovae; and possibly most interesting of all, the uncertain and unpredicted sources, for example relics of inflation and of the symmetry-breaking epoch directly after the Big Bang. eLISA s measurements will allow detailed studies of these signals with high signal-to-noise ratio, addressing most of the key scientific questions raised by ESA s Cosmic Vision programme in the areas of astrophysics and cosmology. They will also provide stringent tests of general relativity in the strong-field dynamical regime, which cannot be probed in any other way. This document not only describes the science but also gives an overview on the mission design and orbits. LISA s heritage in the eLISA design will be

  2. eLISA eccentricity measurements as tracers of binary black hole formation

    OpenAIRE

    Nishizawa, Atsushi; Berti, Emanuele; Klein, Antoine; Sesana, Alberto

    2016-01-01

    Up to hundreds of black hole binaries individually resolvable by eLISA will coalesce in the Advanced LIGO/Virgo band within ten years, allowing for multi-band gravitational wave observations. Binaries formed via dynamical interactions in dense star clusters are expected to have eccentricities $e_0\\sim 10^{-3}$-$10^{-1}$ at the frequencies $f_0=10^{-2}$ Hz where eLISA is most sensitive, while binaries formed in the field should have negligible eccentricity in both frequency bands. We estimate ...

  3. Noise characteristics of a dc SQUID with a resistively shunted inductance

    International Nuclear Information System (INIS)

    Enpuku, K.; Muta, T.; Yoshida, K.; Irie, F.

    1985-01-01

    Noise characteristics of a dc SQUID with an inductance shunted by a damping resistance are studied numerically. It is shown that the damping resistance improves considerably the resolution of the SQUID in the case of large β, where β = 2LI 0 /Phi 0 , I 0 is a critical current, L is a loop inductance and Phi 0 is the flux quantum. The energy resolutions for β = 4 and β = 10 are only about 2 and 4 times larger than that for β = 1, respectively. Furthermore, the ranges of both the bias current and the external flux, where good resolution is obtained, become very wide compared with the conventional SQUID. Therefore, the SQUID with the damping resistance can be used for large β (or L) without the significant degradation of the resolution, and will much improve the coupling properties between the SQUID and the input circuitry. The numerical simulation results are also compared with analytical ones, and a reasonable agreement is obtained

  4. Correlation between fluxgate and SQUID magnetometer data sets for geomagnetic storms

    Directory of Open Access Journals (Sweden)

    Matladi Thabang

    2014-01-01

    Full Text Available There has always been a need to monitor the near Earth's magnetic field, as this monitoring provides understanding and possible predictions of Space Weather events such as geomagnetic storms. Conventional magnetometers such as fluxgates have been used for decades for Space Weather research. The use of highly sensitive magnetometers such as Superconducting QUantum Interference Devices (SQUIDs, promise to give more insight into Space Weather. SQUIDs are relatively recent types of magnetometers that exploit the superconductive effects of flux quantization and Josephson tunneling to measure magnetic flux. SQUIDs have a very broad bandwidth compared to most conventional magnetometers and can measure magnetic flux as low as a few femtotesla. Since SQUIDs have never been used in Space Weather research, unshielded, it is necessary to investigate if they can be reliable Space Weather instruments. The validation is performed by comparing the frequency content of the SQUID and fluxgate magnetometers, as reported by Phiri.

  5. Low-frequency flux noise in YBCO dc SQUIDs cooled in static magnetic fields

    International Nuclear Information System (INIS)

    Sager, M.P.; Bindslev Hansen, J.; Petersen, P.R.E.; Holst, T.; Shen, Y.Q.

    1999-01-01

    The low-frequency flux noise in bicrystal and step-edge YBa 2 Cu 3 O x dc SQUIDs has been investigated. The width, w, of the superconducting strips forming the SQUID frame was varied from 4 to 42 μm. The SQUIDs were cooled in static magnetic fields up to 150 μT. Two types of low-frequency noise dominated, namely 1/f-like noise and random telegraph noise giving a Lorentzian frequency spectrum. The 1/f noise performance of the w = 4, 6 and 7 μm SQUIDs was almost identical, while the SQUIDs with w = 22 and 42 μm showed an order of magnitude higher noise level. Our analysis of the data suggests an exponential increase of the 1/f noise versus the cooling field, exhibiting a characteristic magnetic field around 40 μT. (author)

  6. Robotic 3D SQUID imaging system for practical nondestructive evaluation applications

    International Nuclear Information System (INIS)

    Isawa, K.; Nakayama, S.; Ikeda, M.; Takagi, S.; Tosaka, S.; Kasai, N.

    2005-01-01

    A robotic three-dimensional (3D) scanning superconducting quantum interference device (SQUID) imaging system was developed for practical nondestructive evaluation (NDE) applications. The major feature of this SQUID-NDE system is that the SQUID sensor itself scans in 3D by traveling over the surface of an object during testing without the need for magnetic shielding. This imaging system consists of (i) DC-SQUID gradiometer for effective movement of the sensor, (ii) SQUID sensor manipulator utilizing an articulated-type robot used in industry, (iii) laser charge-coupled-device (CCD) displacement sensor to measure the 3D coordinates of points on the surface of the object, and (iv) computer-aided numerical interpolation scheme for 3D surface reconstruction of the object. The applicability of this system for NDE was demonstrated by successfully detecting artificial damage of cylindrical-shaped steel tubes

  7. Temperature dependence of the effective sensing area of high-Tc dc SQUIDs

    International Nuclear Information System (INIS)

    Brake, H.J.M. ter; Aarnink, W.A.M.; Bosch, P.J. van den; Hilgenkamp, J.W.M.; Flokstra, J.; Rogalla, H.

    1997-01-01

    The effective sensing area of a high-T c dc SQUID depends on temperature. As a consequence, fluctuations in the operating temperature result in apparent magnetic field noise if the SQUID is placed in a background magnetic field. An analysis of this effect for two SQUID types, the square-washer 'Ketchen' type and the inductively shunted type, is performed. For magnetocardiography, the temperature fluctuations (peak to peak) of the latter SQUID type should be below w 0.3 mK at 77 K, and below 2 mK at 55 K, with an earth's field suppression of 40 dB. For the square-washer SQUID the requirements are about 8 times less stringent. (author)

  8. Issues relating to airborne applications of HTS SQUIDs

    CERN Document Server

    Foley, C P; Binks, R A; Lam, S H K; Du, J; Tilbrook, D L; Mitchell, E E; MacFarlane, J C; Lee, J B; Turner, R; Downey, M; Maddever, A

    2002-01-01

    Airborne application of HTS SQUIDs is the most difficult environment for their successful deployment. In order to operate with the sensitivity required for a particular application, there are many issues to be addressed such as the need for very wide dynamic range electronics, motion noise elimination, immunity to large changing magnetic fields and cultural noise sources. This paper reviews what is necessary to achieve an airborne system giving examples in geophysical mineral exploration. It will consider issues relating to device design and fabrication, electronics, dewar design, suspension system requirements and noise elimination methods.

  9. Quantum versus thermally excited fluxoid transitions in a SQUID ring

    International Nuclear Information System (INIS)

    Kurkijaervi, J.

    1980-01-01

    The possibility of quantum tunneling as a mechanism for fluxoid transitions in a SQUID ring is carefully considered neglecting, however, dissipation arising from the quasiparticle current. The tunneling rates are compared with the thermally excited transition rates. The type of experiment Jackel et al. carried out in order to observe the thermal process is analyzed for observing the quantum tunneling. We find the expected result that the temperature at which the quantum process should begin to dominate depends essentially on ω 0 = 1/√LC of the ring. If an underdamped junction with C -13 F can be made the quantum tunneling temperature range should be easy to attain. (orig.)

  10. 3D Inversion of SQUID Magnetic Tensor Data

    DEFF Research Database (Denmark)

    Zhdanov, Michael; Cai, Hongzhu; Wilson, Glenn

    2012-01-01

    Developments in SQUID-based technology have enabled direct measurement of magnetic tensor data for geophysical exploration. For quantitative interpretation, we introduce 3D regularized inversion for magnetic tensor data. For mineral exploration-scale targets, our model studies show that magnetic...... tensor data have significantly improved resolution compared to magnetic vector data for the same model. We present a case study for the 3D regularized inversion of magnetic tensor data acquired over a magnetite skarn at Tallawang, Australia. The results obtained from our 3D regularized inversion agree...

  11. Issues relating to airborne applications of HTS SQUIDs

    International Nuclear Information System (INIS)

    Foley, C P; Leslie, K E; Binks, R A; Lam, S H K; Du, J; Tilbrook, D L; Mitchell, E E; Macfarlane, J C; Lee, J B; Turner, R; Downey, M; Maddever, A

    2002-01-01

    Airborne application of HTS SQUIDs is the most difficult environment for their successful deployment. In order to operate with the sensitivity required for a particular application, there are many issues to be addressed such as the need for very wide dynamic range electronics, motion noise elimination, immunity to large changing magnetic fields and cultural noise sources. This paper reviews what is necessary to achieve an airborne system giving examples in geophysical mineral exploration. It will consider issues relating to device design and fabrication, electronics, dewar design, suspension system requirements and noise elimination methods

  12. Thermal activation and macroscopic quantum tunneling in a DC SQUID

    International Nuclear Information System (INIS)

    Sharifi, F.; Gavilano, J.L.; VanHarlingen, D.J.

    1989-01-01

    The authors report measurements of the transition rate from metastable minima in the two-dimensional 1 of a dc SQUID as a function of applied flux temperature. The authors observe a crossover from energy-activated escape to macroscopic quantum tunneling at a critical temperature. The macroscopic quantum tunneling rate is substantially reduced by damping, and also broadens the crossover region. Most interestingly, the authors observe thermal rates that are suppressed from those predicted by the two-dimensional thermal activation model. The authors discuss possible explanations for this based on the interaction of the macroscopic degree of freedom in the device and energy level effects

  13. Front-end multiplexing—applied to SQUID multiplexing: Athena X-IFU and QUBIC experiments

    Science.gov (United States)

    Prele, D.

    2015-08-01

    As we have seen for digital camera market and a sensor resolution increasing to "megapixels", all the scientific and high-tech imagers (whatever the wave length - from radio to X-ray range) tends also to always increases the pixels number. So the constraints on front-end signals transmission increase too. An almost unavoidable solution to simplify integration of large arrays of pixels is front-end multiplexing. Moreover, "simple" and "efficient" techniques allow integration of read-out multiplexers in the focal plane itself. For instance, CCD (Charge Coupled Device) technology has boost number of pixels in digital camera. Indeed, this is exactly a planar technology which integrates both the sensors and a front-end multiplexed readout. In this context, front-end multiplexing techniques will be discussed for a better understanding of their advantages and their limits. Finally, the cases of astronomical instruments in the millimeter and in the X-ray ranges using SQUID (Superconducting QUantum Interference Device) will be described.

  14. Front-end multiplexing—applied to SQUID multiplexing: Athena X-IFU and QUBIC experiments

    International Nuclear Information System (INIS)

    Prele, D.

    2015-01-01

    As we have seen for digital camera market and a sensor resolution increasing to 'megapixels', all the scientific and high-tech imagers (whatever the wave length - from radio to X-ray range) tends also to always increases the pixels number. So the constraints on front-end signals transmission increase too. An almost unavoidable solution to simplify integration of large arrays of pixels is front-end multiplexing. Moreover, 'simple' and 'efficient' techniques allow integration of read-out multiplexers in the focal plane itself. For instance, CCD (Charge Coupled Device) technology has boost number of pixels in digital camera. Indeed, this is exactly a planar technology which integrates both the sensors and a front-end multiplexed readout. In this context, front-end multiplexing techniques will be discussed for a better understanding of their advantages and their limits. Finally, the cases of astronomical instruments in the millimeter and in the X-ray ranges using SQUID (Superconducting QUantum Interference Device) will be described

  15. Sky Localization of Complete Inspiral-Merger-Ringdown Signals for Nonspinning Black Hole Binaries with LISA

    Science.gov (United States)

    McWilliams, Sean T.; Lang, Ryan N.; Baker, John G.; Thorpe, James Ira

    2011-01-01

    We investigate the capability of LISA to measure the sky position of equal-mass, nonspinning black hole binaries, including for the first time the entire inspiral-merger-ringdown signal, the effect of the LISA orbits, and the complete three-channel LISA response. For an ensemble of systems near the peak of LISA's sensitivity band, with total rest mass of 2 x l0(exp 6) Stellar Mass at a redshift of z = 1 with random orientations and sky positions, we find median sky localization errors of approximately approx. 3 arcminutes. This is comparable to the field of view of powerful electromagnetic telescopes, such as the James Webb Space Telescope, that could be used to search for electromagnetic signals associated with merging black holes. We investigate the way in which parameter errors decrease with measurement time, focusing specifically on the additional information provided during the merger-ringdown segment of the signal. We find that this information improves all parameter estimates directly, rather than through diminishing correlations with any subset of well-determined parameters.

  16. Estudo bibliométrico do descritor “Ergonomia” na base LISA

    Directory of Open Access Journals (Sweden)

    Eliana Maria dos Santos Bahia

    2011-03-01

    Full Text Available Objetivo: O estudo analisa a produção científica sobre ergonomia utilizando a base de dados Library and Information Science Abstracts (LISA. A base de dados LISA, iniciada em 1969, mantém sua cobertura temática na área de Biblioteconomia e Ciência da Informação.Método: No estudo utilizou-se o método da bibliometria aplicada para verificar a produção científica indexada.Resultados: Entre os resultados da busca de termos indexados na base de dados LISA, encontraram-se 503 artigos com o termo “Ergonomic”; 352 artigos, com a expressão “Design”; 111 artigos com o descritor “Systems”; 110 artigos com o termo “Work”; e , 98 artigos com o termo “Evaluation”. Dentre os 34 títulos de periódicos, 4 títulos cobrem 79% dos artigos que tratam sobre Ergonomia na base LISA. Os demais 30 títulos de periódicos cobrem 21% dos artigos indexados sob essa temática.Conclusões: O presente estudo bibliométrico oferece possibilita um panorama de como a ergonomia é percebida na área da Biblioteconomia e Ciência da Informação.

  17. LISA detection of massive black hole binaries: imprint of seed populations and extreme recoils

    International Nuclear Information System (INIS)

    Sesana, A; Volonteri, M; Haardt, F

    2009-01-01

    All the physical processes involved in the formation, merging and accretion history of massive black holes along the hierarchical build-up of cosmic structures are likely to leave an imprint on the gravitational waves detectable by future space-borne missions, such as LISA. We report here the results of recent studies, carried out by means of dedicated simulations of black hole build-up, aiming at understanding the impact on LISA observations of two ingredients that are crucial in every massive black hole formation scenario, namely: (i) the nature and abundance of the first black hole seeds and (ii) the large gravitational recoils following the merger of highly spinning black holes. We predict LISA detection rates spanning two orders of magnitude, in the range 3-300 events per year, depending on the detail of the assumed massive black hole seed model. On the other hand, large recoil velocities do not dramatically compromise the efficiency of LISA observations. The number of detections may drop substantially (by ∼60%), in scenarios characterized by abundant light seeds, but if seeds are already massive and/or relatively rare, the detection rate is basically unaffected.

  18. Numerical code to determine the particle trapping region in the LISA machine

    International Nuclear Information System (INIS)

    Azevedo, M.T. de; Raposo, C.C. de; Tomimura, A.

    1984-01-01

    A numerical code is constructed to determine the trapping region in machine like LISA. The variable magnetic field is two deimensional and is coupled to the Runge-Kutta through the Tchebichev polynomial. Various particle orbits including particle interactions were analysed. Beside this, a strong electric field is introduced to see the possible effects happening inside the plasma. (Author) [pt

  19. Interpolation of the magnetic field at the test masses in eLISA

    International Nuclear Information System (INIS)

    Mateos, I; Díaz-Aguiló, M; Ramos-Castro, J; García-Berro, E; Lobo, A

    2015-01-01

    A feasible design for a magnetic diagnostics subsystem for eLISA will be based on that of its precursor mission, LISA Pathfinder. Previous experience indicates that magnetic field estimation at the positions of the test masses has certain complications. This is due to two reasons. The first is that magnetometers usually back-act due to their measurement principles (i.e., they also create their own magnetic fields), while the second is that the sensors selected for LISA Pathfinder have a large size, which conflicts with space resolution and with the possibility of having a sufficient number of them to properly map the magnetic field around the test masses. However, high-sensitivity and small-sized sensors that significantly mitigate the two aforementioned limitations exist, and have been proposed to overcome these problems. Thus, these sensors will be likely selected for the magnetic diagnostics subsystem of eLISA. Here we perform a quantitative analysis of the new magnetic subsystem, as it is currently conceived, and assess the feasibility of selecting these sensors in the final configuration of the magnetic diagnostic subsystem. (paper)

  20. Modulation of LISA free-fall orbits due to the Earth-Moon system

    Energy Technology Data Exchange (ETDEWEB)

    Cerdonio, Massimo; Marzari, Francesco [Department of Physics, University of Padova and INFN Padova, via Marzolo 8, I-35131 Padova (Italy); De Marchi, Fabrizio [Department of Physics, University of Trento and INFN Trento, I-38100 Povo (Trento) (Italy); De Pietri, Roberto [Department of Physics, University of Parma and INFN Parma I-43100 Parma (Italy); Jetzer, Philippe [Institute of Theoretical Physics, University of Zuerich, Winterhurerstrasse 190, 8057 Zuerich (Switzerland); Mazzolo, Giulio [Max Planck Institut fuer Gravitationsphysik, Callinstrasse 38, 30167 Hannover (Germany); Ortolan, Antonello [INFN Laboratori Nazionali di Legnaro, Viale dell' Universita 35020 Legnaro (Padova) (Italy); Sereno, Mauro, E-mail: fdemarchi@science.unitn.i [Dipartimento di Fisica, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy)

    2010-08-21

    We calculate the effect of the Earth-Moon (EM) system on the free-fall motion of LISA test masses. We show that the periodic gravitational pulling of the EM system induces a resonance with fundamental frequency 1 yr{sup -1} and a series of periodic perturbations with frequencies equal to integer harmonics of the synodic month ({approx_equal} 3.92 x 10{sup -7} Hz). We then evaluate the effects of these perturbations (up to the 6th harmonics) on the relative motions between each test mass couple, finding that they range between 3 mm and 10 pm for the 2nd and 6th harmonic, respectively. If we take the LISA sensitivity curve, as extrapolated down to 10{sup -6} Hz in Bender (2003 Class. Quantum Grav. 20 301-10), we obtain that a few harmonics of the EM system can be detected in the Doppler data collected by the LISA space mission. This suggests that the EM system gravitational near field could provide an additional crosscheck to the calibration of LISA, as extended to such low frequencies.

  1. Modulation of LISA free-fall orbits due to the Earth-Moon system

    International Nuclear Information System (INIS)

    Cerdonio, Massimo; Marzari, Francesco; De Marchi, Fabrizio; De Pietri, Roberto; Jetzer, Philippe; Mazzolo, Giulio; Ortolan, Antonello; Sereno, Mauro

    2010-01-01

    We calculate the effect of the Earth-Moon (EM) system on the free-fall motion of LISA test masses. We show that the periodic gravitational pulling of the EM system induces a resonance with fundamental frequency 1 yr -1 and a series of periodic perturbations with frequencies equal to integer harmonics of the synodic month (≅ 3.92 x 10 -7 Hz). We then evaluate the effects of these perturbations (up to the 6th harmonics) on the relative motions between each test mass couple, finding that they range between 3 mm and 10 pm for the 2nd and 6th harmonic, respectively. If we take the LISA sensitivity curve, as extrapolated down to 10 -6 Hz in Bender (2003 Class. Quantum Grav. 20 301-10), we obtain that a few harmonics of the EM system can be detected in the Doppler data collected by the LISA space mission. This suggests that the EM system gravitational near field could provide an additional crosscheck to the calibration of LISA, as extended to such low frequencies.

  2. Playing Harry Potter: Essays and interviews on fandom and performance, edited by Lisa S. Brenner

    Directory of Open Access Journals (Sweden)

    Abigail De Kosnik

    2016-09-01

    Full Text Available Lisa S. Brenner, editor. Playing Harry Potter: Essays and interviews on fandom and performance. Jefferson, NC: McFarland, 2015, paperback, $29.95 (238p ISBN 978-0-7864-9657-0; e-book $14.43 (5374 KB ISBN 978-1-4766-2136-4, ASIN B012E9G0R6.

  3. PREFACE: Proceedings of the 7th International LISA Symposium, Barcelona, Spain, 16-20 June 2008

    Science.gov (United States)

    Lobo, Alberto; Sopuerta, Carlos F.

    2009-07-01

    In June 2006 the LISA International Science Team (LIST) accepted the bid presented by the Institut d'Estudis Espacials de Catalunya (IEEC) to host the 7th International LISA Symposium. This was during its 11th meeting at the University of Maryland, just before the 6th edition of the Symposium started in NASA's Goddard Space Flight Center. The 7th International LISA Symposium took place at the city of Barcelona, Spain, from 16-20 June 2008, in the premises of CosmoCaixa, a modern Science Museum located in the hills near Tibidabo. Almost 240 delegates registered for the event, a record breaking figure compared to previous editions of the Symposium. Many of the most renowned world experts in LISA, Gravitational Wave Science, and Astronomy, as well as Engineers, attended LISA 7 and produced state-of-the-art presentations, while everybody benefited from the opportunity to have live discussions during the week in a friendly environment. The programme included 31 invited plenary lectures in the mornings, and 8 parallel sessions in the afternoons. These were classified into 7 major areas of research: LISA Technology, LISA PathFinder, LISA PathFinder Data Analysis, LISA Data Analysis, Gravitational Wave sources, Cosmology and Fundamental Physics with LISA and Other Gravitational Wave Detectors. 138 abstracts for communications were received, of which a selection was made by the session convenors which would fit time constraints. Up to 63 posters completed the scientific programme. More details on the programme, including some of the talks, can be found at the Symposium website: http://www.ice.cat/research/LISA_Symposium. There was however a remarkable add-on: Professor Clifford Will delivered a startling presentation to the general public, who completely filled the Auditori—the main Conference Room, 320 seats—and were invited to ask questions to the speaker who had boldly guided them through the daunting world of Black Holes, Waves of Gravity, and other Warped Ideas of

  4. Massive black-hole binary inspirals: results from the LISA parameter estimation taskforce

    International Nuclear Information System (INIS)

    Arun, K G; Babak, Stas; Porter, Edward K; Sintes, Alicia M; Berti, Emanuele; Cutler, Curt; Cornish, Neil; Gair, Jonathan; Hughes, Scott A; Lang, Ryan N; Iyer, Bala R; Sinha, Siddhartha; Mandel, Ilya; Sathyaprakash, Bangalore S; Van Den Broeck, Chris; Trias, Miquel; Volonteri, Marta

    2009-01-01

    The LISA Parameter Estimation Taskforce was formed in September 2007 to provide the LISA Project with vetted codes, source distribution models and results related to parameter estimation. The Taskforce's goal is to be able to quickly calculate the impact of any mission design changes on LISA's science capabilities, based on reasonable estimates of the distribution of astrophysical sources in the universe. This paper describes our Taskforce's work on massive black-hole binaries (MBHBs). Given present uncertainties in the formation history of MBHBs, we adopt four different population models, based on (i) whether the initial black-hole seeds are small or large and (ii) whether accretion is efficient or inefficient at spinning up the holes. We compare four largely independent codes for calculating LISA's parameter-estimation capabilities. All codes are based on the Fisher-matrix approximation, but in the past they used somewhat different signal models, source parametrizations and noise curves. We show that once these differences are removed, the four codes give results in extremely close agreement with each other. Using a code that includes both spin precession and higher harmonics in the gravitational-wave signal, we carry out Monte Carlo simulations and determine the number of events that can be detected and accurately localized in our four population models.

  5. Antibacterial Activity of Melanin from Cuttlefish and Squid Ink

    Directory of Open Access Journals (Sweden)

    Yuspihana Fitrial

    2017-08-01

    Full Text Available Marine environment comprises of many organism which are known to posses bioactive compound as a common means of self-defense or for the protection of eggs and embryos. Class Cephalopods (such as squidand cuttlefish are notable for their defences, such as jetting escape movements, changes in colouration, toxic venom and inking.This study aims to compare the antibacterial activity of melanin from cuttlefish ink (Sepia sp. with squid ink (Loligo sp. against E. coli. Extraction and purification studies were carried out on Sepia and Loligo melanin using a hydrochloric acid 0,5M treatment under mechanical.The melanins were obtained and further evaluated their activity by direct contact methods between melanin and E. coli in nutrient broth.Total microbes was counted by total plate count.Both inks also was tested their activity against E. coli. The results showed that melanin from cuttlefish and squid inks had inhibitory activity at concentrations of 10 mg / ml and 20 mg / mL, respectively reaching 99.99% against E. coli.The inks of both Cephalopods at the same concentration as melanin, did not show any inhibitory activity against E. coli.  The melanin of Sepia sp. have a higher antibacterial activity than the melanin of Loligo sp.

  6. Reduction of environmental MHz noise for SQUID application

    Energy Technology Data Exchange (ETDEWEB)

    Araya, T. [Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 (Japan)]. E-mail: araya@sup.ee.es.osaka-u.ac.jp; Kitamura, Y. [Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 (Japan); Kamishiro, M. [Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 (Japan); Sakuta, K. [Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 (Japan); Itozaki, H. [Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 (Japan)]. E-mail: itozaki@ee.es.osaka-u.ac.jp

    2006-10-01

    It is important to remove large environmental noise in measurement using SQUIDs without magnetic shielding. Active noise control (ANC) is an effective method to remove the environmental noise. The environmental noise has been reduced by the ANC system in the radio frequency region around MHz. The anti-phase waves of the environmental noise should be generated by this system. The ANC system including the phase and amplitude control circuit was developed to make the anti-phase waves in the MHz region. In this paper, sinusoidal waves with a MHz frequency were used as the environmental noise. When a coil antenna was used for a receiver antenna, this ANC system suppressed these sinusoidal waves to the white noise level about 40 dB. When we used a SQUID as a receiver antenna, we also cancelled sinusoidal waves to the white noise level by this system. This shows that the ANC system is useful to reduce an environmental noise when this ANC system is developed to cancel multi-frequency noise.

  7. Reduction of environmental MHz noise for SQUID application

    International Nuclear Information System (INIS)

    Araya, T.; Kitamura, Y.; Kamishiro, M.; Sakuta, K.; Itozaki, H.

    2006-01-01

    It is important to remove large environmental noise in measurement using SQUIDs without magnetic shielding. Active noise control (ANC) is an effective method to remove the environmental noise. The environmental noise has been reduced by the ANC system in the radio frequency region around MHz. The anti-phase waves of the environmental noise should be generated by this system. The ANC system including the phase and amplitude control circuit was developed to make the anti-phase waves in the MHz region. In this paper, sinusoidal waves with a MHz frequency were used as the environmental noise. When a coil antenna was used for a receiver antenna, this ANC system suppressed these sinusoidal waves to the white noise level about 40 dB. When we used a SQUID as a receiver antenna, we also cancelled sinusoidal waves to the white noise level by this system. This shows that the ANC system is useful to reduce an environmental noise when this ANC system is developed to cancel multi-frequency noise

  8. Impact of SQUIDs on functional imaging in neuroscience

    International Nuclear Information System (INIS)

    Penna, Stefania Della; Pizzella, Vittorio; Romani, Gian Luca

    2014-01-01

    This paper provides an overview on the basic principles and applications of magnetoencephalography (MEG), a technique that requires the use of many SQUIDs and thus represents one of the most important applications of superconducting electronics. Since the development of the first SQUID magnetometers, it was clear that these devices could be used to measure the ultra-low magnetic signals associated with the bioelectric activity of the neurons of the human brain. Forty years on from the first measurement of magnetic alpha rhythm by David Cohen, MEG has become a fundamental tool for the investigation of brain functions. The simple localization of cerebral sources activated by sensory stimulation performed in the early years has been successively expanded to the identification of the sequence of neuronal pool activations, thus decrypting information of the hierarchy underlying cerebral processing. This goal has been achieved thanks to the development of complex instrumentation, namely whole head MEG systems, allowing simultaneous measurement of magnetic fields all over the scalp with an exquisite time resolution. The latest trends in MEG, such as the study of brain networks, i.e. how the brain organizes itself in a coherent and stable way, are discussed. These sound applications together with the latest technological developments aimed at implementing systems able to record MEG signals and magnetic resonance imaging (MRI) of the head with the same set-up pave the way to high performance systems for brain functional investigation in the healthy and the sick population. (paper)

  9. Equilibrium vortex motion in two- and three-dimensional superconductors studied with a dc SQUID

    International Nuclear Information System (INIS)

    Shaw, T.J.; Lawrence Berkeley National Lab., CA

    1997-10-01

    The equilibrium motion of vortices in two- and three-dimensional superconductors has been studied with a dc Superconducting QUantum Interference Device (SQUID). This technique has the advantage of probing the system in a non-invasive manner as well as providing dynamic information over many decades in frequency. Through measurements of the spectral density of magnetic flux noise, S Φ (ω), as a function of temperature and applied magnetic field, the effects of proton and heavy ion irradiation on flux noise in crystals of YBa 2 Cu 3 O 7-δ have been measured and compared with the effects on the critical current, J c . Both proton and heavy ion irradiation proved effective at reducing S Φ (ω), with proton irradiation having a larger effect. Measurement of S Φ (ω) due to the equilibrium Kosterlitz-Thouless-Berezinskii transition in two-dimensional Josephson Junction Arrays (JJAs) was studied as a function of temperature for three different arrays and using three different sensors. S Φ is shown to obey dynamic scaling over as many as five decades in frequency, and estimates are made for the dynamic critical exponent z. An analytic theory for the high- and low-frequency behavior of S Φ (ω) is presented and compared to the measured data, with the result that the low-frequency behavior is well described by the theory but the high-frequency behavior is not. Other theories and numerical simulations are described and compared with the data, but none are completely satisfactory. Lastly, suggestions for necessary further theoretical work and possible future experimental work are suggested

  10. The end-to-end testbed of the optical metrology system on-board LISA Pathfinder

    Energy Technology Data Exchange (ETDEWEB)

    Steier, F; Cervantes, F Guzman; Marin, A F GarcIa; Heinzel, G; Danzmann, K [Max-Planck-Institut fuer Gravitationsphysik (Albert-Einstein-Institut) and Universitaet Hannover (Germany); Gerardi, D, E-mail: frank.steier@aei.mpg.d [EADS Astrium Satellites GmbH, Friedrichshafen (Germany)

    2009-05-07

    LISA Pathfinder is a technology demonstration mission for the Laser Interferometer Space Antenna (LISA). The main experiment on-board LISA Pathfinder is the so-called LISA Technology Package (LTP) which has the aim to measure the differential acceleration between two free-falling test masses with an accuracy of 3 x 10{sup -14} ms{sup -2} Hz{sup -1/2} between 1 mHz and 30 mHz. This measurement is performed interferometrically by the optical metrology system (OMS) on-board LISA Pathfinder. In this paper, we present the development of an experimental end-to-end testbed of the entire OMS. It includes the interferometer and its sub-units, the interferometer backend which is a phasemeter and the processing of the phasemeter output data. Furthermore, three-axes piezo-actuated mirrors are used instead of the free-falling test masses for the characterization of the dynamic behaviour of the system and some parts of the drag-free and attitude control system (DFACS) which controls the test masses and the satellite. The end-to-end testbed includes all parts of the LTP that can reasonably be tested on earth without free-falling test masses. At its present status it consists mainly of breadboard components. Some of those have already been replaced by engineering models of the LTP experiment. In the next steps, further engineering and flight models will also be inserted in this testbed and tested against well-characterized breadboard components. The presented testbed is an important reference for the unit tests and can also be used for validation of the on-board experiment during the mission.

  11. Temperature-dependent performance of all-NbN DC-SQUID magnetometers

    Science.gov (United States)

    Liu, Quansheng; Wang, Huiwu; Zhang, Qiyu; Wang, Hai; Peng, Wei; Wang, Zhen

    2017-05-01

    Integrated NbN direct current superconducting quantum interference device (DC-SQUID) magnetometers were developed based on high-quality epitaxial NbN/AlN/NbN Josephson junctions for SQUID applications operating at high temperatures. We report the current-voltage and voltage-flux characteristics and the noise performance of the NbN DC-SQUIDs for temperatures ranging from 4.2 to 9 K. The critical current and voltage swing of the DC-SQUIDs decreased by 15% and 25%, respectively, as the temperature was increased from 4.2 to 9 K. The white flux noise of the DC-SQUID magnetometer at 1 kHz increased from 3.9 μΦ0/Hz1/2 at 4.2 K to 4.8 μΦ0/Hz1/2 at 9 K with 23% increase, corresponding to the magnetic field noise of 6.6 and 8.1 fT/Hz1/2, respectively. The results show that NbN DC-SQUIDs improve the tolerance of the operating temperatures and temperature fluctuations in SQUID applications.

  12. Development of an image processing system in splendid squid quality classification

    Science.gov (United States)

    Masunee, Niyada; Chaiprapat, Supapan; Waiyagan, Kriangkrai

    2013-07-01

    Agricultural products typically exhibit high variance in quality characteristics. To assure customer satisfaction and control manufacturing productivity, quality classification is necessary to screen off defective items and to grade the products. This article presents an application of image processing techniques on squid grading and defect discrimination. A preliminary study indicated that surface color was an efficient determinant to justify quality of splendid squids. In this study, a computer vision system (CVS) was developed to examine the characteristics of splendid squids. Using image processing techniques, squids could be classified into three different quality grades as in accordance with an industry standard. The developed system first sifted through squid images to reject ones with black marks. Qualified squids were graded on a proportion of white, pink, and red regions appearing on their bodies by using fuzzy logic. The system was evaluated on 100 images of squids at different quality levels. It was found that accuracy obtained by the proposed technique was 95% compared with sensory evaluation of an expert.

  13. Sensitive YBCO nanoSQUIDs for the investigation of small spin systems

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Benedikt; Schwarz, Tobias; Woelbing, Roman; Martinez-Perez, Maria Jose; Kleiner, Reinhold; Koelle, Dieter [Tuebingen Univ. (Germany). Physikalisches Inst. and Center for Collective Quantum Phenomena in LISA+; Reiche, Christopher F.; Muehl, Thomas; Buechner, Bernd [Leibniz Institute for Solid State and Materials Research IFW Dresden (Germany)

    2015-07-01

    We report on advances in the realization of dc YBCO nanoSQUIDs for continuous measurement of magnetic nanoparticle magnetization loops in strong magnetic fields up to the Tesla range, applied in the plane of the SQUID loop at temperatures of 4 K and below. Our grain boundary junction based YBCO SQUIDs are patterned by focused ion beam milling and feature a constriction next to the SQUID loop, allowing for on-chip SQUID modulation and bias reversal readout schemes. Using numerical simulations based on London theory, the spin sensitivity S{sub μ}{sup 1/2} = S{sub Φ}{sup 1/2} / φ{sub μ} was improved by optimizing both the flux noise S{sub Φ}{sup 1/2} and the coupling factor φ{sub μ} = Φ / μ (Φ is the magnetic flux coupled into the SQUID loop by a particle with magnetic moment μ). For optimized experimental devices, flux noise levels down to 50 nΦ{sub 0} / Hz{sup 1/2} in the white noise limit have been achieved, corresponding to a calculated spin sensitivity of only a few μ{sub B} / Hz{sup 1/2}. Further, the magnetization reversal of a Fe filled carbon nanotube attached to a YBCO nanoSQUID was traced out.

  14. Characteristics of an HTS-SQUID gradiometer with ramp-edge Josephson junctions and its application on robot-based 3D-mobile compact SQUID NDE system

    Energy Technology Data Exchange (ETDEWEB)

    Hatsukade, Y., E-mail: hatukade@ens.tut.ac.jp [Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan); Hayashi, K.; Shinyama, Y.; Kobayashi, Y. [Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan); Adachi, S.; Tanabe, K. [International Superconductivity Technology Center/Superconductivity Research Laboratory, 10-13, Shinonome 1-chome, Koto-ku, Tokyo 135-0062 (Japan); Tanaka, S. [Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan)

    2011-11-15

    We investigated behavior of HTS-dc-SQUID gradiometers with ramp-edge Josephson junctions (JJs) in ac and dc magnetic fields. In the both fields, the gradiometers show higher durability against entry of flux vortices than SQUIDs with bicrystal JJs. A robot-based SQUID NDE system utilizing the gradiometer was developed in an unshielded environment. Detectability of the system to detect non-through cracks in double-layer structures was demonstrated. A new excitation coil was applied to detect cracks that oriented vertical and parallel to the baseline of the gradiometer. In this paper, we investigated detailed behavior of novel HTS-dc-SQUID gradiometers with ramp-edge Josephson junctions (JJs) in both an ac magnetic field and a dc magnetic field. In the both fields, the novel gradiometers shows the superior performance to the conventional YBa{sub 2}Cu{sub 3}O{sub 7-x} (YBCO) HTS-dc-SQUID gradiometer and a bare HTS-dc-SQUID ring with bicrystal JJs concerning durability against entry and hopping of flux vortices, probably due to their differential pickup coils without a grain boundary and multilayer structure of the ramp-edge JJs. A robot-based compact HTS-SQUID NDE system utilizing the novel gradiometer was reviewed, and detectability of the system to detect non-through cracks in a carbon fiber reinforced plastic (CFRP)/Al double-layer structure was demonstrated. A new excitation coil in which the supplied currents flowed in the orthogonal directions was applied to detect cracks that oriented vertical and parallel to the baseline of the gradiometer.

  15. Prospects on the application of HTS SQUID magnetometry to nondestructive evaluation (NDE)

    Science.gov (United States)

    Weinstock, H.

    1993-04-01

    In light of recent advances in the fabrication of low-noise HTS SQUIDs, a review is presented on the use of LTS SQUID magnetometry for nondestructive evaluation (NDE). Examples are given on applications relating to defects in steel, subsurface cracks in aircraft frames, and voids in non-metallic structures. HTS SQUIDs may make a significant difference in the acceptance of these applications because sensing coils will be closer to a sample under test, there will be greater instrument portability and the problem of bringing liquid helium to remote locations will be eliminated.

  16. Mismatch between the eye and the optic lobe in the giant squid.

    Science.gov (United States)

    Liu, Yung-Chieh; Liu, Tsung-Han; Yu, Chun-Chieh; Su, Chia-Hao; Chiao, Chuan-Chin

    2017-07-01

    Giant squids ( Architeuthis ) are a legendary species among the cephalopods. They live in the deep sea and are well known for their enormous body and giant eyes. It has been suggested that their giant eyes are not adapted for the detection of either mates or prey at distance, but rather are best suited for monitoring very large predators, such as sperm whales, at distances exceeding 120 m and at a depth below 600 m (Nilsson et al. 2012 Curr. Biol. 22 , 683-688. (doi:10.1016/j.cub.2012.02.031)). However, it is not clear how the brain of giant squids processes visual information. In this study, the optic lobe of a giant squid ( Architeuthis dux , male, mantle length 89 cm), which was caught by local fishermen off the northeastern coast of Taiwan, was scanned using high-resolution magnetic resonance imaging in order to examine its internal structure. It was evident that the volume ratio of the optic lobe to the eye in the giant squid is much smaller than that in the oval squid ( Sepioteuthis lessoniana ) and the cuttlefish ( Sepia pharaonis ). Furthermore, the cell density in the cortex of the optic lobe is significantly higher in the giant squid than in oval squids and cuttlefish, with the relative thickness of the cortex being much larger in Architeuthis optic lobe than in cuttlefish. This indicates that the relative size of the medulla of the optic lobe in the giant squid is disproportionally smaller compared with these two cephalopod species. This morphological study of the giant squid brain, though limited only to the optic lobe, provides the first evidence to support that the optic lobe cortex, the visual information processing area in cephalopods, is well developed in the giant squid. In comparison, the optic lobe medulla, the visuomotor integration centre in cephalopods, is much less developed in the giant squid than other species. This finding suggests that, despite the giant eye and a full-fledged cortex within the optic lobe, the brain of giant

  17. jSquid: a Java applet for graphical on-line network exploration.

    Science.gov (United States)

    Klammer, Martin; Roopra, Sanjit; Sonnhammer, Erik L L

    2008-06-15

    jSquid is a graph visualization tool for exploring graphs from protein-protein interaction or functional coupling networks. The tool was designed for the FunCoup web site, but can be used for any similar network exploring purpose. The program offers various visualization and graph manipulation techniques to increase the utility for the user. jSquid is available for direct usage and download at http://jSquid.sbc.su.se including source code under the GPLv3 license, and input examples. It requires Java version 5 or higher to run properly. erik.sonnhammer@sbc.su.se Supplementary data are available at Bioinformatics online.

  18. Frequency-domain multiplex with eight-input SQUID and readout electronics over 1MHz

    International Nuclear Information System (INIS)

    Masui, K.; Takei, Y.; Ikeda, H.; Kimura, S.; Mitsuda, K.; Yamasaki, N.Y.

    2006-01-01

    In a magnetic summation method, TES and SQUID driving circuits are isolated and thus small crosstalk and stray impedance are expected. Since a FLL circuit with a large bandwidth and a small noise level is required for a SQUID, we designed and produced an electronics to meet our design of multiplexing with an 8-input SQUID. The FLL circuit achieved an open loop-gain bandwidth product of 8MHz with 1m wire length, which is enough for a TES to be operated with a bias current of 70μA, and a noise level of 30pA/Hz

  19. Step edge Josephson junctions and high temperature superconducting quantum interference device (SQUID) gradiometers

    International Nuclear Information System (INIS)

    Millar, Alasdair J.

    2002-01-01

    This thesis is concerned with the development of Superconducting Quantum Interference Device (SQUID) gradiometers based on the high temperature superconductor YBa 2 Cu 3 O 7-δ (YBCO). A step-edge Josephson junction fabrication process was developed to produce sufficiently steep (>60 deg) step-edges such that junctions exhibited RSJ-like current-voltage characteristics. The mean I C R N product of a sample of twenty step-edge junctions was 130μV. Step-edge dc SQUIDs with inductances between 67pH and 114pH were fabricated. Generally the SQUIDs had an intrinsic white flux noise in the 10-30μΦ 0 /√Hz range, with the best device, a 70pH SQUID, exhibiting a white flux noise of 5μΦ 0 /√Hz. Different first-order SQUID gradiometer designs were fabricated from single layers of YBCO. Two single-layer gradiometer (SLG) designs were fabricated on 10x10mm 2 substrates. The best balance and lowest gradient sensitivity measured for these devices were 1/300 and 308fT/cm√Hz (at 1 kHz) respectively. The larger baseline and larger flux capture area of the pick-up loops in a large area SLG design, fabricated on 30x10mm 2 substrates, resulted in significant improvements in the balance and gradient field sensitivity with 1/1000 and 50fT/cm√Hz (at 1kHz) measured respectively. To reduce the uniform field effective area of SLOs and therefore reduce the direct pick-up of environmental field noise when operated unshielded, a novel gradiometric SQUID (G-SQUID) device was developed. Fabricated from a single layer of YBCO, the G-SQUIDs with inductances of 67pH, had small uniform field effective areas of approximately 2μm 2 - more than two orders of magnitude smaller than the uniform field effective areas of conventional narrow linewidth SQUIDs of similar inductance. Two designs of G-SQUID were fabricated on 10x10mm 2 substrates. Due to their small effective areas, when cooled unshielded these devices showed no increase in their white flux noise. The best balance achieved for a G-SQUID

  20. Study of test-mass charging process in the LISA missions due to diffuse γ-rays

    International Nuclear Information System (INIS)

    Finetti, N; Scrimaglio, R; Grimani, C; Fabi, M

    2009-01-01

    Gravitational inertial sensors will be placed on board the Laser Interferometer Space Antenna (LISA) and aboard its precursor mission LISA Pathfinder (LISA-PF) in order to detect low frequency gravitational waves in space. Free-floating test-masses (Au 7 Pt 3 cubes) will be housed in inertial sensors for detecting possible laser signal variations induced by gravitational waves. Charging of the LISA test-masses due to exposure of the spacecraft to cosmic radiation and energetic solar particles will affect operation of gravitational inertial sensors. In this paper we report on the role of diffuse γ-rays in charging the LISA and LISA-PF test-masses with respect to protons and helium nuclei. The diffuse γ-ray flux in the Galaxy has been interpolated taking into account the outcomes of recent calculations. A comparison with γ-ray observations gathered by different experiments (COMPTEL and EGRET, Milagro, Whipple, HEGRA, TIBET) has been carried out. Simulations of the test-mass charging process have been performed by means of the FLUKA2006.3b package. Monte Carlo simulations of the interaction of cosmic particles with the LISA spacecraft indicate that the diffuse γ-ray contribution to the average steady-state test-mass charging rate and to the single-sided power spectrum of the charge rate noise is marginal with respect to that due to galactic cosmic-rays.

  1. Magnetic imaging of unconventional superconductors by scanning SQUID microscopy

    International Nuclear Information System (INIS)

    Hykel, D.

    2011-01-01

    We present the development of a scanning SQUID/AFM microscope and measurements performed on different samples. The microscope can take topographic and magnetic images simultaneously. The magnetic resolution is of the order of 10 -4 Φ 0 √Hz and the spatial resolution of the SQUIDs used in this thesis goes up to 600 nm. The scanning range is 70 μm * 85 μm. The temperature range accessible is between 200 mK and 10 K at the time of writing. Measurements on a thin rhenium film (80 nm) give an estimate of the minimal pinning force of a vortex of about 3.9 * 10 -16 N. Furthermore, the penetration depth λ on this sample was determined as a function of temperature. For T → 0, λ →79 nm. We have for the first time shown local measurements of the domain structure of the superconducting ferromagnet UCoGe and determined the average domain size in the virgin state (10 μm). By magnetic imaging we were capable of determining the magnetic field difference above opposite domains along the c-axis to be 45 G and 16 G along the b-axis. Due to these magnetic field measurements we were able to give an upper limit for the domain wall width (∼ 1μm) and domain reconstruction depth (100 nm). This is supported by simple calculations leading to a domain wall width of several angstroms. Thus UCoGe can be considered an ideal Ising ferromagnet. Different possible domain structures for an Ising ferromagnet have been discussed. The complicated domain structure found in the zero field cooled virgin state corresponds to up domains embedded in larger down domains and vice versa. We have shown evidence for coexistence of superconductivity and ferromagnetism. The weak Meissner effect can be explained by a spontaneous vortex state, put forward by other groups. Numerical simulations suggest that the strong magnetic background signal and the limited spatial and magnetic resolution of the used SQUID made it difficult to resolve the expected spontaneous vortex state. The relaxation of the

  2. The SPICA-SAFARI Detector System : TES Detector Arrays With Frequency-Division Multiplexed SQUID Readout

    NARCIS (Netherlands)

    Jackson, B. D.; de Korte, P. A. J.; van der Kuur, J.; Mauskopf, P. D.; Beyer, J.; Bruijn, M. P.; Cros, A.; Gao, J. -R.; Griffin, D.; den Hartog, R.; Kiviranta, M.; de Lange, G.; van Leeuwen, B. -J.; Macculi, C.; Ravera, L.; Trappe, N.; van Weers, H.; Withington, S.

    The SAFARI instrument is a far-infrared imaging Fourier transform spectrometer for JAXA's SPICA mission. Taking advantage of the low emission of SPICA's 5 K telescope, SAFARI will provide sky background-limited, Nyquist-sampled spectroscopic imaging of a 2' x 2' field-of-view over 34-210 mu m,

  3. In-orbit performance of the LISA Pathfinder drag-free and attitude control system

    Science.gov (United States)

    Schleicher, A.; Ziegler, T.; Schubert, R.; Brandt, N.; Bergner, P.; Johann, U.; Fichter, W.; Grzymisch, J.

    2018-04-01

    LISA Pathfinder is a technology demonstrator mission that was funded by the European Space Agency and that was launched on December 3, 2015. LISA Pathfinder has been conducting experiments to demonstrate key technologies for the gravitational wave observatory LISA in its operational orbit at the L1 Lagrange point of the Earth-Sun system until final switch off on July 18, 2017. These key technologies include the inertial sensors, the optical metrology system, a set of µ-propulsion cold gas thrusters and in particular the high performance drag-free and attitude control system (DFACS) that controls the spacecraft in 15 degrees of freedom during its science phase. The main goal of the DFACS is to shield the two test masses inside the inertial sensors from all external disturbances to achieve a residual differential acceleration between the two test masses of less than 3 × 10-14 m/s2/√Hz over the frequency bandwidth of 1-30 mHz. This paper focuses on two important aspects of the DFACS that has been in use on LISA Pathfinder: the DFACS Accelerometer mode and the main DFACS Science mode. The Accelerometer mode is used to capture the test masses after release into free flight from the mechanical grabbing mechanism. The main DFACS Science Mode is used for the actual drag-free science operation. The DFACS control system has very strong interfaces with the LISA Technology Package payload which is a key aspect to master the design, development, and analysis of the DFACS. Linear as well as non-linear control methods are applied. The paper provides pre-flight predictions for the performance of both control modes and compares these predictions to the performance that is currently achieved in-orbit. Some results are also discussed for the mode transitions up to science mode, but the focus of the paper is on the Accelerometer mode performance and on the performance of the Science mode in steady state. Based on the achieved results, some lessons learnt are formulated to extend

  4. Detection of Rapid Atrial Arrhythmias in SQUID Magnetocardiography

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ki Woong; Kwon, Hyuk Chan; Kim, Ki Dam; Lee, Yong Ho; Kim, Jin Mok; Kim, In Seon; Lim, Hyun Kyoon; Park, Yong Ki [Biomagnetism Research, Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of); Kim, Doo Sang [Seoul Veterans Hospital, Seoul (Korea, Republic of); Lim, Seung Pyung [Chungnam National University Hospital, Daejeon (Korea, Republic of)

    2005-10-15

    We propose a method to measure atrial arrhythmias (AA) such as atrial fibrillation (Afb) and atrial flutter (Afl) with a SQUID magnetocardiograph (MCG) system. To detect AA is one of challenging topics in MCG. As the AA generally have irregular rhythm and atrio-ventricular conduction, the MCG signal cannot be improved by QRS averaging; therefore a SQUID MCG system having a high SNR is required to measure informative atrial excitation with a single scan. In the case of Afb, diminished f waves are much smaller than normal P waves because the sources are usually located on the posterior wall of the heart. In this study, we utilize an MCG system measuring tangential field components, which is known to be more sensitive to a deeper current source. The average noise spectral density of the whole system in a magnetic shielded room was 10 fT/Hz(a) 1 Hz and 5 fT/Hz(a) 100 Hz. We measured the MCG signals of patients with chronic Afb and Afl. Before the AA measurement, the comparison between the measurements in supine and prone positions for P waves has been conducted and the experiment gave a result that the supine position is more suitable to measure the atrial excitation. Therefore, the AA was measured in subject's supine position. Clinical potential of AA measurement in MCG is to find an aspect of a reentry circuit and to localize the abnormal stimulation noninvasively. To give useful information about the abnormal excitation, we have developed a method, separative synthetic aperture magnetometry (sSAM). The basic idea of sSAM is to visualize current source distribution corresponding to the atrial excitation, which are separated from the ventricular excitation and the Gaussian sensor noises. By using sSAM, we localized the source of an Afl successfully.

  5. SQUID-detected magnetic resonance imaging in microtesla magnetic fields

    International Nuclear Information System (INIS)

    McDermott, Robert; Kelso, Nathan; Lee, SeungKyun; Moessle, Michael; Mueck, Michael; Myers, Whittier; Haken, Bernard ten; Seton, H.C.; Trabesinger, Andreas H.; Pines, Alex; Clarke, John

    2003-01-01

    We describe studies of nuclear magnetic resonance (NMR) spectroscopy and magnetic resonance imaging (MRI) of liquid samples at room temperature in microtesla magnetic fields. The nuclear spins are prepolarized in a strong transient field. The magnetic signals generated by the precessing spins, which range in frequency from tens of Hz to several kHz, are detected by a low-transition temperature dc SQUID (Superconducting QUantum Interference Device) coupled to an untuned, superconducting flux transformer configured as an axial gradiometer. The combination of prepolarization and frequency-independent detector sensitivity results in a high signal-to-noise ratio and high spectral resolution (∼1 Hz) even in grossly inhomogeneous magnetic fields. In the NMR experiments, the high spectral resolution enables us to detect the 10-Hz splitting of the spectrum of protons due to their scalar coupling to a 31P nucleus. Furthermore, the broadband detection scheme combined with a non-resonant field-reversal spin echo allows the simultaneous observation of signals from protons and 31P nuclei, even though their NMR resonance frequencies differ by a factor of 2.5. We extend our methodology to MRI in microtesla fields, where the high spectral resolution translates into high spatial resolution. We demonstrate two-dimensional images of a mineral oil phantom and slices of peppers, with a spatial resolution of about 1 mm. We also image an intact pepper using slice selection, again with 1-mm resolution. In further experiments we demonstrate T1-contrast imaging of a water phantom, some parts of which were doped with a paramagnetic salt to reduce the longitudinal relaxation time T1. Possible applications of this MRI technique include screening for tumors and integration with existing multichannel SQUID systems for brain imaging

  6. SQUID-Detected Magnetic Resonance Imaging in MicroteslaFields

    Energy Technology Data Exchange (ETDEWEB)

    Moessle, Michael; Hatridge, Michael; Clarke, John

    2006-08-14

    amplitude in MRI using laser polarized noble gases such as {sup 3}He or {sup 129}Xe (10-12). Hyperpolarized gases were used successfully to image the human lung in fields on the order of several mT (13-15). To overcome the sensitivity loss of Faraday detection at low frequencies, ultrasensitive magnetometers based on the Superconducting QUantum Interference Device (SQUID) (16) are used to detect NMR and MRI signals (17-24). Recently, SQUID-based MRI systems capable of acquiring in vivo images have appeared. For example, in the 10-mT system of Seton et al. (18) signals are coupled to a SQUID via a superconducting tuned circuit, while Clarke and coworkers (22, 25, 26) developed a system at 132 {micro}T with an untuned input circuit coupled to a SQUID. In a quite different approach, atomic magnetometers have been used recently to detect the magnetization (27) and NMR signal (28) of hyperpolarized gases. This technique could potentially be used for low-field MRI in the future. The goal of this review is to summarize the current state-of-the-art of MRI in microtesla fields detected with SQUIDs. The principles of SQUIDs and NMR are briefly reviewed. We show that very narrow NMR linewidths can be achieved in low magnetic fields that are quite inhomogeneous, with illustrative examples from spectroscopy. After describing our ultralow-field MRI system, we present a variety of images. We demonstrate that in microtesla fields the longitudinal relaxation T{sub 1} is much more material dependent than is the case in high fields; this results in a substantial improvement in 'T{sub 1}-weighted contrast imaging'. After outlining the first attempts to combine microtesla NMR with magnetoencephalography (MEG) (29), we conclude with a discussion of future directions.

  7. Imaging of current density distributions with a Nb weak-link scanning nano-SQUID microscope

    Science.gov (United States)

    Shibata, Yusuke; Nomura, Shintaro; Kashiwaya, Hiromi; Kashiwaya, Satoshi; Ishiguro, Ryosuke; Takayanagi, Hideaki

    2015-10-01

    Superconducting quantum interference devices (SQUIDs) are accepted as one of the highest magnetic field sensitive probes. There are increasing demands to image local magnetic fields to explore spin properties and current density distributions in a two-dimensional layer of semiconductors or superconductors. Nano-SQUIDs have recently attracting much interest for high spatial resolution measurements in nanometer-scale samples. Whereas weak-link Dayem Josephson junction nano-SQUIDs are suitable to miniaturization, hysteresis in current-voltage (I-V) characteristics that is often observed in Dayem Josephson junction is not desirable for a scanning microscope. Here we report on our development of a weak-link nano-SQUIDs scanning microscope with small hysteresis in I-V curve and on reconstructions of two-dimensional current density vector in two-dimensional electron gas from measured magnetic field.

  8. Technology for SQUID systems for the application in magnetically disturbed environment. Final report

    International Nuclear Information System (INIS)

    Schultze, V.; Fritzsch, L.; Thrum, F.; Stolz, R.; Chwala, A.

    1996-06-01

    International available SQUID systems, as used for example in biomagnetic research, obtain high sensitivities for magnetic fields or magnetic fieldgradients. However, these systems were optimised for operation in magnetically shielded rooms. Goal of this project was to develop SQUIDs suppressing the external noise and therefore are able to operate without external shielding in normal environments. As a consequence, the required Nb/AlO x /Nb technology has also been developed. The resulting planar SQUID gradiometers as produced at the IPHT, reached a suppression of homogeneous fields up to 5 x 10 4 for a magnetic field sensitivity c , project. SQUID gradiometers, produced using YBCO technology, were successfully operated in non shielded eddy current NDE measurements in the lab. (orig.) [de

  9. Growth of juvenile shrimp Metapenaeus monoceros fed with squid and mussel

    Digital Repository Service at National Institute of Oceanography (India)

    Achuthankutty, C.T.; Nair, S.R.S.; Krishnakumari, L.

    Small juveniles of both sexes and females of large juveniles of Metapenaeus monoceros attained faster growth with squid diet. Males of large juveniles registered better growth with mussel diet. No significant difference was observed in moult weights...

  10. High-T /SUB c/ Superconducting integrated circuit: a dc SQUID with input coil

    International Nuclear Information System (INIS)

    Di Iorio, M.S.; Beasley, M.R.

    1985-01-01

    We have fabricated a high transition temperature superconducting integrated circuit consisting of a dc SQUID and an input coupling coil. The purpose is to ascertain the generic problems associated with constructing a high-T /SUB c/ circuit as well as to fabricate a high performance dc SQUID. The superconductor used for both the SQUID and the input coil is Nb 3 Sn which must be deposited at 800 0 C. Importantly, the insulator separating SQUID and input coil maintains its integrity at this elevated temperature. A hole in the insulator permits contact to the innermost winding of the coil. This contact has been achieved without significant degradation of the superconductivity. Consequently, the device operates over a wide temperature range, from below 4.2 K to near T /SUB c/

  11. Development of a Flow-Through SQUID System for Non-Destructive Evaluation of MRI Wire

    National Research Council Canada - National Science Library

    Wellstood, Frederick C

    2007-01-01

    ...) superconducting quantum interference device (SQUID) system. The ability to detect small defects in km-long sections of NbTi magnet wire could improve the production yield of high-field magnets for power and medical applications...

  12. Analysis of the ac SQUID with low inductance and low critical current

    DEFF Research Database (Denmark)

    Sørensen, O. H.

    1976-01-01

    The properties of the ac SQUID magnetometer has been analyzed. The results are valid in the low-inductance low-critical-current regime, where the Lri0 producted is belowthe value at which the relation between the enclosed and externally applied magnetic dc flux becomes reentrant. The effects...... of the screening current circulating in the SQUID ring as well as of the SQUID-ring time constant, tau-Lr/R9 are taken into account. Here LR IS THE SQUID-ring inductance, and R is the shunt resistance in the shunted junction model assumed to describe the weak link. It is shown that for finite values of omegatau...... constriuctively with the result that the optimal response occurs at a definite and finite value of omegatau. If omegatau is increased beyond this optimal value the weak link behavior is dominated by the Ohmic current channel implying that only if the shunt conductance contains a term depending...

  13. 76 FR 66260 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Science.gov (United States)

    2011-10-26

    ...) of scup, 184,280 lb (83,588 kg) of black sea bass, and 200,000 lb (90,718 kg) of bluefish. Project... summer flounder, scup, black sea bass, longfin squid, butterfish, and Atlantic bluefish, and assessment...

  14. Review: Lisa Mackenrodt, Swahili Spirit Possession and Islamic Healing in Contemporary Tanzania: The Jinn Fly on Friday (2011 Buchbesprechung: Lisa Mackenrodt, Swahili Spirit Possession and Islamic Healing in Contemporary Tanzania: The Jinn Fly on Friday (2011

    Directory of Open Access Journals (Sweden)

    Jigal Beez

    2013-01-01

    Full Text Available Review of the monograph:Lisa Mackenrodt, Swahili Spirit Possession and Islamic Healing in Contemporary Tanzania: The Jinn Fly on Friday, Hamburg: Verlag Dr. Kovač, 2011, ISBN 978-3-8300-5806-9, 216 pagesBesprechung der Monographie:Lisa Mackenrodt, Swahili Spirit Possession and Islamic Healing in Contemporary Tanzania: The Jinn Fly on Friday, Hamburg: Verlag Dr. Kovač, 2011, ISBN 978-3-8300-5806-9, 216 Seiten

  15. LISA Pathfinder E2E performance simulation: optical and self-gravity stability analysis

    Science.gov (United States)

    Brandt, N.; Fichter, W.; Kersten, M.; Lucarelli, S.; Montemurro, F.

    2005-05-01

    End-to-end (E2E) modelling and simulation, i.e. verifying the science performance of LISA Pathfinder (spacecraft and payload), is mandatory in order to minimize mission risks. In this paper, focus is on two particular applications of the E2E performance simulator currently being developed at EADS Astrium GmbH: the opto-dynamical stability and the self-gravity disturbance stability analysis. The E2E models applied here comprise the opto-dynamical modelling of the optical metrology systems (OMS) laser interferometry, the thermo-elastic distortion modelling of the OMS optical elements and the self-gravity disturbance model accounting for structural distortions. Preliminary analysis results are presented in detail, identifying shortcomings of the current LISA technology package (LTP) mounting baseline. As a consequence, the design is now being revised.

  16. LISA Pathfinder E2E performance simulation: optical and self-gravity stability analysis

    International Nuclear Information System (INIS)

    Brandt, N; Fichter, W; Kersten, M; Lucarelli, S; Montemurro, F

    2005-01-01

    End-to-end (E2E) modelling and simulation, i.e. verifying the science performance of LISA Pathfinder (spacecraft and payload), is mandatory in order to minimize mission risks. In this paper, focus is on two particular applications of the E2E performance simulator currently being developed at EADS Astrium GmbH: the opto-dynamical stability and the self-gravity disturbance stability analysis. The E2E models applied here comprise the opto-dynamical modelling of the optical metrology systems (OMS) laser interferometry, the thermo-elastic distortion modelling of the OMS optical elements and the self-gravity disturbance model accounting for structural distortions. Preliminary analysis results are presented in detail, identifying shortcomings of the current LISA technology package (LTP) mounting baseline. As a consequence, the design is now being revised

  17. Lifetime testing UV LEDs for use in the LISA charge management system

    Science.gov (United States)

    Hollington, D.; Baird, J. T.; Sumner, T. J.; Wass, P. J.

    2017-10-01

    As a future charge management light source, UV light-emitting diodes (UV LEDs) offer far superior performance in a range of metrics compared to the mercury lamps used in the past. As part of a qualification program a number of short wavelength UV LEDs have been subjected to a series of lifetime tests for potential use on the laser interferometer space antenna (LISA) mission. These tests were performed at realistic output levels for both fast and continuous discharging in either a DC or pulsed mode of operation and included a DC fast discharge test spanning 50 days, a temperature dependent pulsed fast discharge test spanning 21 days and a pulsed continuous discharge test spanning 507 days. Two types of UV LED have demonstrated lifetimes equivalent to over 25 years of realistic mission usage with one type providing a baseline for LISA and the other offering a backup solution.

  18. Lifetime testing UV LEDs for use in the LISA charge management system

    International Nuclear Information System (INIS)

    Hollington, D; Baird, J T; Sumner, T J; Wass, P J

    2017-01-01

    As a future charge management light source, UV light-emitting diodes (UV LEDs) offer far superior performance in a range of metrics compared to the mercury lamps used in the past. As part of a qualification program a number of short wavelength UV LEDs have been subjected to a series of lifetime tests for potential use on the laser interferometer space antenna (LISA) mission. These tests were performed at realistic output levels for both fast and continuous discharging in either a DC or pulsed mode of operation and included a DC fast discharge test spanning 50 days, a temperature dependent pulsed fast discharge test spanning 21 days and a pulsed continuous discharge test spanning 507 days. Two types of UV LED have demonstrated lifetimes equivalent to over 25 years of realistic mission usage with one type providing a baseline for LISA and the other offering a backup solution. (paper)

  19. LISA: A performance assessment code for geological repositories of radioactive waste

    International Nuclear Information System (INIS)

    Bertozzi, G.; Saltelli, A.

    1985-01-01

    LISA, developed at JRC-Ispra, is a statistical code, which calculates the radiation exposures and risks associated with radionuclide releases from geological repositories of nuclear waste. The assessment methodology is described briefly. It requires that a number of probabilistic components be quantified and introduced in the analysis; the results are thus expressed in terms of risk. The subjective judgment of experts may be necessary to quantify the probabilities of occurrence of rare geological events. Because of large uncertainties in input data, statistical treatment of the Monte Carlo type is utilized for the analysis; thus, the output from LISA is obtained in the form of distributions. A few results of an application to a probabilistic scenario for a repository mined in a clay bed are illustrated

  20. Construction of an optical test-bed for eLISA

    International Nuclear Information System (INIS)

    Lieser, Maike; Isleif, K-S; Schuster, S; Tröbs, M; Veith, S; Heinzel, G; Danzmann, K; Fitzsimons, E; Killow, C; Perreur-Lloyd, M; Robertson, D; Ward, H

    2016-01-01

    In the planned eLISA mission a key part of the system is the optical bench that holds the interferometers for reading out the inter-spacecraft distance and the test mass position. We report on ongoing technology development for the eLISA optical system like the back-link between the optical benches and the science interferometer where the local beam is interfered with the received beam from the distant spacecraft. The focus will be on a setup to investigate the tilt-to-pathlength coupling in the science interferometer. To test the science interferometer in the lab a second bench providing a laser beam and a reference interferometer is needed. We present a setup with two ultra-stable low expansion glass benches and bonded optics. To suppress the tilt-to-pathlength coupling to the required level (few μm/rad) imaging optics are placed in front of the interferometer photo diodes. (paper)

  1. The Mock LISA Data Challenges: from Challenge 1B to Challenge 3

    International Nuclear Information System (INIS)

    Babak, Stanislav; Porter, Edward K; Gair, Jonathan; Baker, John G; Arnaud, Keith; Benacquista, Matthew J; Cornish, Neil J; Crowder, Jeff; Vallisneri, Michele; Cutler, Curt; Larson, Shane L; Plagnol, Eric; Vecchio, Alberto; Barack, Leor; Blaut, Arkadiusz; Fairhurst, Stephen; Harry, Ian; Gong Xuefei; Khurana, Deepak; Krolak, Andrzej

    2008-01-01

    The Mock LISA Data Challenges are a programme to demonstrate and encourage the development of LISA data-analysis capabilities, tools and techniques. At the time of this workshop, three rounds of challenges had been completed, and the next was about to start. In this paper we provide a critical analysis of the entries to the latest completed round, Challenge 1B. The entries confirm the consolidation of a range of data-analysis techniques for galactic and massive-black-hole binaries, and they include the first convincing examples of detection and parameter estimation of extreme-mass-ratio inspiral sources. In this paper we also introduce the next round, Challenge 3. Its data sets feature more realistic waveform models (e.g., galactic binaries may now chirp, and massive-black-hole binaries may precess due to spin interactions), as well as new source classes (bursts from cosmic strings, isotropic stochastic backgrounds) and more complicated nonsymmetric instrument noise

  2. arXiv Probing non-Gaussian Stochastic Gravitational Wave Backgrounds with LISA

    CERN Document Server

    Bartolo, Nicola; Figueroa, Daniel G.; Garcia-Bellido, Juan; Peloso, Marco; Pieroni, Mauro; Ricciardone, Angelo; Sakellariadou, Mairi; Sorbo, Lorenzo; Tasinato, Gianmassimo

    The stochastic gravitational wave background (SGWB) contains a wealth of information on astrophysical and cosmological processes. A major challenge of upcoming years will be to extract the information contained in this background and to disentangle the contributions of different sources. In this paper we provide the formalism to extract, from the correlation of three signals in the Laser Interferometer Space Antenna (LISA), information about the tensor three-point function, which characterizes the non-Gaussian properties of the SGWB. Compared to the two-point function, the SGWB three-point function has a richer dependence on the gravitational wave momenta and chiralities, and a larger number of signal channels. It can be used therefore as a powerful discriminator between different models. We provide LISA's response functions to a general SGWB three-point function. As examples, we study in full detail the cases of an equilateral and squeezed SGWB bispectra, and provide the explicit form of the response functio...

  3. LTP - LISA technology package: Development challenges of a spaceborne fundamental physics experiment

    Energy Technology Data Exchange (ETDEWEB)

    Gerndt, R, E-mail: ruediger.gerndt@astrium.eads.ne [Astrium Satellites GmbH, Claude-Dornier-Str., 88090 Immenstaad (Germany)

    2009-03-01

    The LISA Technology Package (LTP) is the main payload onboard the LISA Pathfinder Spacecraft. The LTP Instrument together with the Drag-Free Attitude Control System (DFACS) and the respective LTP and DFACS operational software forms the LTP Experiment. It is completed by the FEEPs of the LPF spacecraft that are controlled by DFACS in order to control the spacecraft's attitude along with the experiment's needs. This article concentrates on aspects of the Industrial development of the LTP Instrument items and on essential performance issues of LTP. Examples of investigations on specific issue will highlight the kind of special problems to be solved for LTP in close cooperation with the Scientific Community.

  4. Detection of Double White Dwarf Binaries with Gaia, LSST and eLISA

    Science.gov (United States)

    Korol, V.; Rossi, E. M.; Groot, P. J.

    2017-03-01

    According to simulations around 108 double degenerate white dwarf binaries are expected to be present in the Milky Way. Due to their intrinsic faintness, the detection of these systems is a challenge, and the total number of detected sources so far amounts only to a few tens. This will change in the next two decades with the advent of Gaia, the LSST and eLISA. We present an estimation of how many compact DWDs with orbital periods less than a few hours we will be able to detect 1) through electromagnetic radiation with Gaia and LSST and 2) through gravitational wave radiation with eLISA. We find that the sample of simultaneous electromagnetic and gravitational waves detections is expected to be substantial, and will provide us a powerful tool for probing the white dwarf astrophysics and the structure of the Milky Way, letting us into the era of multi-messenger astronomy for these sources.

  5. Possible Periodic Orbit Control Maneuvers for an eLISA Mission

    Science.gov (United States)

    Bender, Peter L.; Welter, Gary L.

    2012-01-01

    This paper investigates the possible application of periodic orbit control maneuvers for so-called evolved-LISA (eLISA) missions, i.e., missions for which the constellation arm lengths and mean distance from the Earth are substantially reduced. We find that for missions with arm lengths of 106 km and Earth-trailing distance ranging from approx. 12deg to 20deg over the science lifetime, the occasional use of the spacecraft micro-Newton thrusters for constellation configuration maintenance should be able to essentially eliminate constellation distortion caused by Earth-induced tidal forces at a cost to science time of only a few percent. With interior angle variation kept to approx. +/-0:1deg, the required changes in the angles between the laser beam pointing directions for the two arms from any spacecraft could be kept quite small. This would considerably simplify the apparatus necessary for changing the transmitted beam directions.

  6. Searching for massive black hole binaries in the first Mock LISA Data Challenge

    International Nuclear Information System (INIS)

    Cornish, Neil J; Porter, Edward K

    2007-01-01

    The Mock LISA Data Challenge is a worldwide effort to solve the LISA data analysis problem. We present here our results for the massive black hole binary (BBH) section of round 1. Our results cover challenge 1.2.1, where the coalescence of the binary is seen, and challenge 1.2.2, where the coalescence occurs after the simulated observational period. The data stream is composed of Gaussian instrumental noise plus an unknown BBH waveform. Our search algorithm is based on a variant of the Markov chain Monte Carlo method that uses Metropolis-Hastings sampling and thermostated frequency annealing. We present results from the training data sets where we know the parameter values a priori and the blind data sets where we were informed of the parameter values after the challenge had finished. We demonstrate that our algorithm is able to rapidly locate the sources, accurately recover the source parameters and provide error estimates for the recovered parameters

  7. Supermassive Black Holes as Revealed by LISA: How Gravitational Wave Astronomy Will be a Game Changer

    Science.gov (United States)

    Holley-Bockelmann, Kelly

    2018-04-01

    Astronomers now know that supermassive black holes are in nearly every galaxy.Though these black holes are an observational certainty, nearly every aspect of their evolution -- from their birth, to their fuel source, to their basic dynamics -- is a matter of lively debate. Fortunately, LISA, a space-based gravitational wave observatory set to launch in 2034, will revolutionize this field by providing data that is complementary to electromagnetic observations as well as data in regimes that are electromagnetically dark. This talk will touch on our current understanding of how SMBHs form, evolve, and alter their galaxy host, and will outline the theoretical, computational and observational work needed to make the most of LISA observations.

  8. The bases for the development of high-temperature integrated SQUID-systems

    International Nuclear Information System (INIS)

    Polushkin, V.N.

    1992-01-01

    The current state of high-T c superconducting thin-film Josephson junctions and SQUIDs developing is reviewed. The prospects of application of new devices in supersensitive measurement apparatus are analyzed. It is shown that high T c SQUIDs are able seriously to influence further development of information and measurement engineering as on their base the series of microelectronic elements and devices of new generation can be built. 55 refs.; 7 figs.; 2 tabs

  9. The bases for the development of high-temperature integrated squid-systems

    International Nuclear Information System (INIS)

    Polushkin, V.N.

    1992-01-01

    The current state of high-Tc superconducting thinfilm Josepson junctions and SQUIDs developing is reviewed. The prospects of application of new devices in supersensitive measurement apparatus are analyzed. It is shown that high T c SQUIDs are able seriously to influence further development of information and measurement engineering as on their base the series of microelectronic elements and devices of new generation can be built. 84 refs.; 16 figs.; 3 tabs

  10. Lisa B Signorello, ScD, ScM | Division of Cancer Prevention

    Science.gov (United States)

    Lisa Signorello is the Director and Chief of the Cancer Prevention Fellowship Program (CPFP) Branch in the National Cancer Institute's Division of Cancer Prevention. Dr. Signorello served as Deputy Director of the CPFP from August 2014 to November 2017 and came to the NCI after having held academic positions at the Harvard School of Public Health, Harvard Medical School, and Vanderbilt University, as well as having had significant private sector research experience. |

  11. Laser frequency stabilization and stray light issues for LISA and other future multi-spacecraft missions Project

    Data.gov (United States)

    National Aeronautics and Space Administration — "The Laser Interferometer Space Antenna (LISA) is a joint NASA/ESA project which will use laser interferometry between drag-free proof masses to measure...

  12. Identification of four squid species by quantitative real-time polymerase chain reaction.

    Science.gov (United States)

    Ye, Jian; Feng, Junli; Liu, Shasha; Zhang, Yanping; Jiang, Xiaona; Dai, Zhiyuan

    2016-02-01

    Squids are distributed worldwide, including many species of commercial importance, and they are often made into varieties of flavor foods. The rapid identification methods for squid species especially their processed products, however, have not been well developed. In this study, quantitative real-time PCR (qPCR) systems based on specific primers and TaqMan probes have been established for rapid and accurate identification of four common squid species (Ommastrephes bartramii, Dosidicus gigas, Illex argentinus, Todarodes pacificus) in Chinese domestic market. After analyzing mitochondrial genes reported in GenBank, the mitochondrial cytochrome b (Cytb) gene was selected for O. bartramii detection, cytochrome c oxidase subunit I (COI) gene for D. gigas and T. Pacificus detection, ATPase subunit 6 (ATPase 6) gene for I. Argentinus detection, and 12S ribosomal RNA (12S rDNA) gene for designing Ommastrephidae-specific primers and probe. As a result, all the TaqMan systems are of good performance, and efficiency of each reaction was calculated by making standard curves. This method could detect target species either in single or mixed squid specimen, and it was applied to identify 12 squid processed products successfully. Thus, it would play an important role in fulfilling labeling regulations and squid fishery control. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Squid-derived chitin oligosaccharides are a chemotactic signal during colonization by Vibrio fischeri.

    Science.gov (United States)

    Mandel, Mark J; Schaefer, Amy L; Brennan, Caitlin A; Heath-Heckman, Elizabeth A C; Deloney-Marino, Cindy R; McFall-Ngai, Margaret J; Ruby, Edward G

    2012-07-01

    Chitin, a polymer of N-acetylglucosamine (GlcNAc), is noted as the second most abundant biopolymer in nature. Chitin serves many functions for marine bacteria in the family Vibrionaceae ("vibrios"), in some instances providing a physical attachment site, inducing natural genetic competence, and serving as an attractant for chemotaxis. The marine luminous bacterium Vibrio fischeri is the specific symbiont in the light-emitting organ of the Hawaiian bobtail squid, Euprymna scolopes. The bacterium provides the squid with luminescence that the animal uses in an antipredatory defense, while the squid supports the symbiont's nutritional requirements. V. fischeri cells are harvested from seawater during each host generation, and V. fischeri is the only species that can complete this process in nature. Furthermore, chitin is located in squid hemocytes and plays a nutritional role in the symbiosis. We demonstrate here that chitin oligosaccharides produced by the squid host serve as a chemotactic signal for colonizing bacteria. V. fischeri uses the gradient of host chitin to enter the squid light organ duct and colonize the animal. We provide evidence that chitin serves a novel function in an animal-bacterial mutualism, as an animal-produced bacterium-attracting synomone.

  14. Demonstration of AC and DC charge control for the LISA test masses

    Science.gov (United States)

    Olatunde, Taiwo Janet

    2018-01-01

    Taiwo Olatunde, Stephen Apple, Andrew Chilton, Samantha Parry, Peter Wass, Guido Mueller, John W. Conklin The residual test mass acceleration in LISA must be below 3 fm/s2/√Hz at all frequencies between 0.1 and 3 mHz. Test mass charge coupled with stray electrical potentials and external electromagnetic fields is a well-known source of acceleration noise. LISA Pathfinder uses Hg lamps emitting mostly around 254 nm to discharge the test masses via photoemission, but a future LISA mission launched around 2030 will likely replace the lamps with newer UV LEDs with lower mass, better power efficiency, smaller size and higher bandwidth. This presentation will discuss charge control demonstrated on the torsion pendulum in AC and DC modes at the University of Florida using latest generation UV LEDs producing light at 240 nm with energy above the work function of pure Au. Initial results of Au quantum efficiency measurements (number of emitted electrons per incident photons) which is critical for bi-polar charge control will also be presented.

  15. Renormalized second post-Newtonian spin contributions to the accumulated orbital phase for LISA sources

    International Nuclear Information System (INIS)

    Gergely, Laszlo Arpad; Mikoczi, Balazs

    2009-01-01

    We give here a new third post-Newtonian (3PN) spin-spin contribution (in the PN parameter ε) to the accumulated orbital phase of a compact binary, arising from the spin-orbit precessional motion of the spins. In the equal mass case, this contribution vanishes, but Laser Interferometer Space Antenna (LISA) sources of merging supermassive binary black holes have typically a mass ratio of 1:10. For such nonequal masses, this 3PN correction is periodic in time, with a period approximately ε -1 times larger than the period of gravitational waves. We derive a renormalized and simpler expression of the spin-spin coefficient at 2PN, as an average over the time scale of this period of the combined 2PN and 3PN contribution. We also find that for LISA sources the quadrupole-monopole contribution to the phase dominates over the spin-spin contribution, while the self-spin contribution is negligible even for the dominant spin. Finally, we define a renormalized total spin coefficient σ to be employed in the search for gravitational waves emitted by LISA sources.

  16. Low-Frequency Gravitational-Wave Science with eLISA/ NGO

    Science.gov (United States)

    Amaro-Seoane, Pau; Aoudia, Sofiane; Babak, Stanislav; Binetruy, Pierre; Berti, Emanuele; Bohe, Alejandro; Caprini, Chiara; Colpi, Monica; Cornish, Neil J.; Danzmann, Karsten; hide

    2011-01-01

    We review the expected science performance of the New Gravitational-Wave Observatory (NGO, a.k.a. eLISA), a mission under study by the European Space Agency for launch in the early 2020s. eLISA will survey the low-frequency gravitational-wave sky (from 0.1 mHz to 1 Hz), detecting and characterizing a broad variety of systems and events throughout the Universe, including the coalescences of massive black holes brought together by galaxy mergers; the inspirals of stellar-mass black holes and compact stars into central galactic black holes; several millions of ultracompact binaries, both detached and mass transferring, in the Galaxy; and possibly unforeseen sources such as the relic gravitational-wave radiation from the early Universe. eLISA's high signal-to-noise measurements will provide new insight into the structure and history of the Universe, and they will test general relativity in its strong-field dynamical regime.

  17. Sub-pm{{\\sqrt{Hz}^{-1}}} non-reciprocal noise in the LISA backlink fiber

    Science.gov (United States)

    Fleddermann, Roland; Diekmann, Christian; Steier, Frank; Tröbs, Michael; Heinzel, Gerhard; Danzmann, Karsten

    2018-04-01

    The future space-based gravitational wave detector laser interferometer space antenna (LISA) requires bidirectional exchange of light between its two optical benches on board of each of its three satellites. The current baseline foresees a polarization-maintaining single-mode fiber for this backlink connection. Phase changes which are common in both directions do not enter the science measurement, but differential (‘non-reciprocal’) phase fluctuations directly do and must thus be guaranteed to be small enough. We have built a setup consisting of a Zerodur baseplate with fused silica components attached to it using hydroxide-catalysis bonding and demonstrated the reciprocity of a polarization-maintaining single-mode fiber at the 1 pm \\sqrt{Hz}-1 level as is required for LISA. We used balanced detection to reduce the influence of parasitic optical beams on the reciprocity measurement and a fiber length stabilization to avoid nonlinear effects in our phase measurement system (phase meter). For LISA, a different phase meter is planned to be used that does not show this nonlinearity. We corrected the influence of beam angle changes and temperature changes on the reciprocity measurement in post-processing.

  18. Common Bias Readout for TES Array on Scanning Transmission Electron Microscope

    Science.gov (United States)

    Yamamoto, R.; Sakai, K.; Maehisa, K.; Nagayoshi, K.; Hayashi, T.; Muramatsu, H.; Nakashima, Y.; Mitsuda, K.; Yamasaki, N. Y.; Takei, Y.; Hidaka, M.; Nagasawa, S.; Maehata, K.; Hara, T.

    2016-07-01

    A transition edge sensor (TES) microcalorimeter array as an X-ray sensor for a scanning transmission electron microscope system is being developed. The technical challenge of this system is a high count rate of ˜ 5000 counts/second/array. We adopted a 64 pixel array with a parallel readout. Common SQUID bias, and common TES bias are planned to reduce the number of wires and the resources of a room temperature circuit. The reduction rate of wires is 44 % when a 64 pixel array is read out by a common bias of 8 channels. The possible degradation of the energy resolution has been investigated by simulations and experiments. The bias fluctuation effects of a series connection are less than those of a parallel connection. Simple calculations expect that the fluctuations of the common SQUID bias and common TES bias in a series connection are 10^{-7} and 10^{-3}, respectively. We constructed 8 SQUIDs which are connected to 8 TES outputs and a room temperature circuit for common bias readout and evaluated experimentally. Our simulation of crosstalk indicates that at an X-ray event rate of 500 cps/pixel, crosstalk will broaden a monochromatic line by about 0.01 %, or about 1.5 eV at 15 keV. Thus, our design goal of 10 eV energy resolution across the 0.5-15 keV band should be achievable.

  19. Magnetic behavior of arrays of nickel nanowires

    International Nuclear Information System (INIS)

    Karim, S.; Maaz, K.; Ahmed, M.; Nisar, A.

    2012-01-01

    Recently, there is an increasing interest in magnetic nano wires because of their unusual properties compared to the bulk materials. To understand the complexity of nano wire arrays and to improve their potential in various applications more studies are still needed, for example, to understand completely the effect of geometrical factors, i.e. aspect ratio, areal density etc., on magnetic properties of these arrays. In this work, arrays of nickel nano wires with aspect ratio is proportional to 1200 and diameter ranging between 25-100 nm were fabricated by electrodeposition in etched ion track templates. Samples with areal density from 1 X 10/sup 6/ cm/sup -2/ to 1 X 10/ sup 8/ cm/sup -2/ were prepared. Measurements of magnetic hysteresis loops were performed at room temperature with SQUID magnetometer and magnetic properties of arrays of different diameters and aspect ratios were compared. Coercivity of the wires showed strong dependence on aspect ratio, diameter and microstructure. Room temperature coercivity of the wires showed a maximum at is proportional to 40 nm diameter and arrays with high density of nano wires showed lower coercivity. The results were discussed by taking into account anisotropies originating from the shape, crystalline structure and magnetostatic interactions among the wires and by previous experimental observations in literature. (Orig./A.B.)

  20. Influence of inductance induced noise in an YBa2Cu3O7 dc-SQUID at high operation temperatures

    DEFF Research Database (Denmark)

    Nilsson, P. Å.; Claeson, T.; Hansen, J. B.

    1994-01-01

    The voltage modulation depth of a high T(c) dc-SQUID was measured at temperatures close to T(c) and compared to a model by Enpuku et al. where the flux noise from the SQUID inductance is taken into account. The device was an YBa2Cu3O7 dc-SQUID made on a bicrystal substrate of SrTiO3. The design w...

  1. Apparatus and method for detecting a magnetic anomaly contiguous to remote location by SQUID gradiometer and magnetometer systems

    Science.gov (United States)

    Overton, W.C. Jr.; Steyert, W.A. Jr.

    1981-05-22

    A superconducting quantum interference device (SQUID) magnetic detection apparatus detects magnetic fields, signals, and anomalies at remote locations. Two remotely rotatable SQUID gradiometers may be housed in a cryogenic environment to search for and locate unambiguously magnetic anomalies. The SQUID magnetic detection apparatus can be used to determine the azimuth of a hydrofracture by first flooding the hydrofracture with a ferrofluid to create an artificial magnetic anomaly therein.

  2. Array capabilities and future arrays

    International Nuclear Information System (INIS)

    Radford, D.

    1993-01-01

    Early results from the new third-generation instruments GAMMASPHERE and EUROGAM are confirming the expectation that such arrays will have a revolutionary effect on the field of high-spin nuclear structure. When completed, GAMMASHPERE will have a resolving power am order of magnitude greater that of the best second-generation arrays. When combined with other instruments such as particle-detector arrays and fragment mass analysers, the capabilites of the arrays for the study of more exotic nuclei will be further enhanced. In order to better understand the limitations of these instruments, and to design improved future detector systems, it is important to have some intelligible and reliable calculation for the relative resolving power of different instrument designs. The derivation of such a figure of merit will be briefly presented, and the relative sensitivities of arrays currently proposed or under construction presented. The design of TRIGAM, a new third-generation array proposed for Chalk River, will also be discussed. It is instructive to consider how far arrays of Compton-suppressed Ge detectors could be taken. For example, it will be shown that an idealised open-quote perfectclose quotes third-generation array of 1000 detectors has a sensitivity an order of magnitude higher again than that of GAMMASPHERE. Less conventional options for new arrays will also be explored

  3. Optical parameters of the tunable Bragg reflectors in squid.

    Science.gov (United States)

    Ghoshal, Amitabh; Demartini, Daniel G; Eck, Elizabeth; Morse, Daniel E

    2013-08-06

    Cephalopods (e.g. octopus, squid and cuttlefish) dynamically tune the colour and brightness of their skin for camouflage and communication using specialized skin cells called iridocytes. We use high-resolution microspectrophotometry to investigate individual tunable Bragg structures (consisting of alternating reflectin protein-containing, high-refractive index lamellae and low-refractive index inter-lamellar spaces) in live and chemically fixed iridocytes of the California market squid, Doryteuthis opalescens. This subcellular, single-stack microspectrophotometry allows for spectral normalization, permitting use of a transfer-matrix model of Bragg reflectance to calculate all the parameters of the Bragg stack-the refractive indices, dimensions and numbers of the lamellae and inter-lamellar spaces. Results of the fitting analyses show that eight or nine pairs of low- and high-index layers typically contribute to the observed reflectivity in live cells, whereas six or seven pairs of low- and high-index layers typically contribute to the reflectivity in chemically fixed cells. The reflectin-containing, high-index lamellae of live cells have a refractive index proportional to the peak reflectivity, with an average of 1.405 ± 0.012 and a maximum around 1.44, while the reflectin-containing lamellae in fixed tissue have a refractive index of 1.413 ± 0.015 suggesting a slight increase of refractive index in the process of fixation. As expected, incremental changes in refractive index contribute to the greatest incremental changes in reflectivity for those Bragg stacks with the most layers. The excursions in dimensions required to tune the measured reflected wavelength from 675 (red) to 425 nm (blue) are a decrease from ca 150 to 80 nm for the high-index lamellae and from ca 120 to 50 nm for the low-index inter-lamellar spaces. Fixation-induced dimensional changes also are quantified, leading us to suggest that further microspectrophotometric analyses of this iridocyte

  4. SNP Arrays

    Directory of Open Access Journals (Sweden)

    Jari Louhelainen

    2016-10-01

    Full Text Available The papers published in this Special Issue “SNP arrays” (Single Nucleotide Polymorphism Arrays focus on several perspectives associated with arrays of this type. The range of papers vary from a case report to reviews, thereby targeting wider audiences working in this field. The research focus of SNP arrays is often human cancers but this Issue expands that focus to include areas such as rare conditions, animal breeding and bioinformatics tools. Given the limited scope, the spectrum of papers is nothing short of remarkable and even from a technical point of view these papers will contribute to the field at a general level. Three of the papers published in this Special Issue focus on the use of various SNP array approaches in the analysis of three different cancer types. Two of the papers concentrate on two very different rare conditions, applying the SNP arrays slightly differently. Finally, two other papers evaluate the use of the SNP arrays in the context of genetic analysis of livestock. The findings reported in these papers help to close gaps in the current literature and also to give guidelines for future applications of SNP arrays.

  5. Microwave SQUID multiplexer demonstration for cosmic microwave background imagers

    Science.gov (United States)

    Dober, B.; Becker, D. T.; Bennett, D. A.; Bryan, S. A.; Duff, S. M.; Gard, J. D.; Hays-Wehle, J. P.; Hilton, G. C.; Hubmayr, J.; Mates, J. A. B.; Reintsema, C. D.; Vale, L. R.; Ullom, J. N.

    2017-12-01

    Key performance characteristics are demonstrated for the microwave superconducting quantum interference device (SQUID) multiplexer (μmux) coupled to transition edge sensor (TES) bolometers that have been optimized for cosmic microwave background (CMB) observations. In a 64-channel demonstration, we show that the μmux produces a white, input referred current noise level of 29 pA/ √{H z } at a microwave probe tone power of -77 dB, which is well below the expected fundamental detector and photon noise sources for a ground-based CMB-optimized bolometer. Operated with negligible photon loading, we measure 98 pA/ √{H z } in the TES-coupled channels biased at 65% of the sensor normal resistance. This noise level is consistent with that predicted from bolometer thermal fluctuation (i.e., phonon) noise. Furthermore, the power spectral density is white over a range of frequencies down to ˜100 mHz, which enables CMB mapping on large angular scales that constrain the physics of inflation. Additionally, we report cross-talk measurements that indicate a level below 0.3%, which is less than the level of cross-talk from multiplexed readout systems in deployed CMB imagers. These measurements demonstrate the μmux as a viable readout technique for future CMB imaging instruments.

  6. Development of improved superconductive axial gradiometers for biomagnetic SQUID applications

    Science.gov (United States)

    Budnyk, M. M.; Minov, Yu. D.; Lyakhno, V. Yu.; Desnenko, V. A.; Linnik, A. S.; Shopen, O. B.

    2018-03-01

    SQUID magnetometers for biomagnetic measurements are equipped with superconductive gradiometers which are required to provide a high signal-to-noise ratio at low frequencies, sufficient mechanical strength and sustained performance under repeated thermal cycles, as well as a low level of intrinsic magnetic noise. This paper describes the design of a gradiometer made with a carbon-fiber reinforced composite material for magnetic cardiography measurements. The thermal coefficient of linear expansion (TCLE) of the carbon fiber composite can be precisely adjusted to match that of the superconducting detector coil wire. This is achieved thanks to the difference in the TCLE of carbon fibers in the longitudinal and transverse directions and is realized by varying the laying directions of the fiber in the composite. The data of magnetic susceptibility measurements on carbon fiber composite are reported, showing the magnetic susceptibility about six times smaller than that of graphite. The presented gradiometer design provides a high degree of balancing and is patented along side other specific techniques.

  7. An interchangeable scanning Hall probe/scanning SQUID microscope

    International Nuclear Information System (INIS)

    Tang, Chiu-Chun; Lin, Hui-Ting; Wu, Sing-Lin; Chen, Tse-Jun; Wang, M. J.; Ling, D. C.; Chi, C. C.; Chen, Jeng-Chung

    2014-01-01

    We have constructed a scanning probe microscope for magnetic imaging, which can function as a scanning Hall probe microscope (SHPM) and as a scanning SQUID microscope (SSM). The scanning scheme, applicable to SHPM and SSM, consists of a mechanical positioning (sub) micron-XY stage and a flexible direct contact to the sample without a feedback control system for the Z-axis. With the interchangeable capability of operating two distinct scanning modes, our microscope can incorporate the advantageous functionalities of the SHPM and SSM with large scan range up to millimeter, high spatial resolution (⩽4 μm), and high field sensitivity in a wide range of temperature (4.2 K-300 K) and magnetic field (10 −7 T-1 T). To demonstrate the capabilities of the system, we present magnetic images scanned with SHPM and SSM, including a RbFeB magnet and a nickel grid pattern at room temperature, surface magnetic domain structures of a La 2/3 Ca 1/3 MnO 3 thin film at 77 K, and superconducting vortices in a striped niobium film at 4.2 K

  8. Development of Contaminant Detection System using HTS SQUIDs

    International Nuclear Information System (INIS)

    Ohtani, T.; Tanaka, S.; Narita, Y.; Ariyoshi, S.; Suzuki, S.

    2015-01-01

    In terms of food safety, mixture of contaminants in food is a serious problem for not only consumers but also manufacturers. In general, the target size of the metallic contaminant to be removed is 0.5 mm. However, it is a difficult task for manufacturers to achieve this target, because of lower system sensitivity. Therefore, we developed a food contaminant detection system based on high-Tc RF superconducting quantum interference devices (SQUIDs), which are highly sensitive magnetic sensors. This study aims to improve the signal to noise ratio (SNR) of the system and detect a 0.5 mm diameter steel ball. Using a real time digital signal processing technique along with analog band-pass filters, we improved the SNR of the system. Owing to the improved SNR, a steel ball with a diameter as small as 0.3 mm, with stand-off distance of 117 mm was successfully detected. These results suggest that the proposed system is a promising candidate for the detection of metallic contaminants in food products

  9. An interchangeable scanning Hall probe/scanning SQUID microscope

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Chiu-Chun; Lin, Hui-Ting; Wu, Sing-Lin [Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Chen, Tse-Jun; Wang, M. J. [Institute of Astronomy and Astrophysics, Academia Sinica, Taipei 10617, Taiwan (China); Ling, D. C. [Department of Physics, Tamkang University, Tamsui Dist., New Taipei City 25137, Taiwan (China); Chi, C. C.; Chen, Jeng-Chung [Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, Hsinchu 30013, Taiwan (China)

    2014-08-15

    We have constructed a scanning probe microscope for magnetic imaging, which can function as a scanning Hall probe microscope (SHPM) and as a scanning SQUID microscope (SSM). The scanning scheme, applicable to SHPM and SSM, consists of a mechanical positioning (sub) micron-XY stage and a flexible direct contact to the sample without a feedback control system for the Z-axis. With the interchangeable capability of operating two distinct scanning modes, our microscope can incorporate the advantageous functionalities of the SHPM and SSM with large scan range up to millimeter, high spatial resolution (⩽4 μm), and high field sensitivity in a wide range of temperature (4.2 K-300 K) and magnetic field (10{sup −7} T-1 T). To demonstrate the capabilities of the system, we present magnetic images scanned with SHPM and SSM, including a RbFeB magnet and a nickel grid pattern at room temperature, surface magnetic domain structures of a La{sub 2/3}Ca{sub 1/3}MnO{sub 3} thin film at 77 K, and superconducting vortices in a striped niobium film at 4.2 K.

  10. Dynamic Characteristics of S-band DC SQUID Amplifier

    DEFF Research Database (Denmark)

    Prokopenko, G. V.; Shitov, S. V.; Koshelets, I. L. L. V. P.

    2003-01-01

    A low-noise rf amplifier based on a de SQUID (SQA) has been tested in the frequency range 3.0-4.6 GHz in the open-loop configuration. The following parameters have been measured for the single-stage balanced type SQA at 4.0 GHz: gain (12 +/- 1) dB, 3 dB bandwidth of 500 MHz and noise temperature (1.......0 +/- 0.25) K. For the nonbalanced type SQA at 4.0 GHz gain was (15 +/-1) dB, 3 dB bandwidth 200 MHz and noise temperature (0.5 +/- 0.25) K. The improved performance is obtained due to the increased characteristic voltage (approximate to 420 muV) of the small-area (down to 0.7-0.9 mum(2)) high-quality Nb......-AlOx-Nb SIS junctions. The saturation power (normalized to 1 GHz) referred to the input at 1 dB gain compression is estimated as approximate to55 K*GHz at a bias voltage of 60 muV. The reasons for saturation of the SQA are discussed....

  11. Sperm from sneaker male squids exhibit chemotactic swarming to CO₂.

    Science.gov (United States)

    Hirohashi, Noritaka; Alvarez, Luis; Shiba, Kogiku; Fujiwara, Eiji; Iwata, Yoko; Mohri, Tatsuma; Inaba, Kazuo; Chiba, Kazuyoshi; Ochi, Hiroe; Supuran, Claudiu T; Kotzur, Nico; Kakiuchi, Yasutaka; Kaupp, U Benjamin; Baba, Shoji A

    2013-05-06

    Behavioral traits of sperm are adapted to the reproductive strategy that each species employs. In polyandrous species, spermatozoa often form motile clusters, which might be advantageous for competing with sperm from other males. Despite this presumed advantage for reproductive success, little is known about how sperm form such functional assemblies. Previously, we reported that males of the coastal squid Loligo bleekeri produce two morphologically different euspermatozoa that are linked to distinctly different mating behaviors. Consort and sneaker males use two distinct insemination sites, one inside and one outside the female's body, respectively. Here, we show that sperm release a self-attracting molecule that causes only sneaker sperm to swarm. We identified CO2 as the sperm chemoattractant and membrane-bound flagellar carbonic anhydrase as its sensor. Downstream signaling results from the generation of extracellular H(+), intracellular acidosis, and recovery from acidosis. These signaling events elicit Ca(2+)-dependent turning behavior, resulting in chemotactic swarming. These results illuminate the bifurcating evolution of sperm underlying the distinct fertilization strategies of this species. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. EFFECT OF DETERGENT ON ELECTRICAL PROPERTIES OF SQUID AXON MEMBRANE.

    Science.gov (United States)

    KISHIMOTO, U; ADELMAN, W J

    1964-05-01

    The effects of detergents on squid giant axon action and resting potentials as well as membrane conductances in the voltage clamp have been studied. Anionic detergents (sodium lauryl sulfate, 0.1 to 1.0 mM; dimethyl benzene sulfonate, 1 to 20 mM, pH 7.6) cause a temporary increase and a later decrease of action potential height and the value of the resting potential. Cationic detergent (cetyl trimethyl ammonium chloride, 6 x 10(-5)M or more, pH 7.6) generally brings about immediate and irreversible decreases in the action and resting potentials. Non-ionic detergent (tween 80, 0.1 M, pH 7.6) causes a slight reversible reduction of action potential height without affecting the value of the resting potential. Both anionic and cationic detergents generally decrease the sodium and potassium conductances irreversibly. The effect of non-ionic detergent is to decrease the sodium conductance reversibly, leaving the potassium conductance almost unchanged.

  13. Microwave SQUID Multiplexer Demonstration for Cosmic Microwave Background Imagers.

    Science.gov (United States)

    Dober, B; Becker, D T; Bennett, D A; Bryan, S A; Duff, S M; Gard, J D; Hays-Wehle, J P; Hilton, G C; Hubmayr, J; Mates, J A B; Reintsema, C D; Vale, L R; Ullom, J N

    2017-12-01

    Key performance characteristics are demonstrated for the microwave SQUID multiplexer (µmux) coupled to transition edge sensor (TES) bolometers that have been optimized for cosmic microwave background (CMB) observations. In a 64-channel demonstration, we show that the µmux produces a white, input referred current noise level of [Formula: see text] at -77 dB microwave probe tone power, which is well below expected fundamental detector and photon noise sources for a ground-based CMB-optimized bolometer. Operated with negligible photon loading, we measure [Formula: see text] in the TES-coupled channels biased at 65% of the sensor normal resistance. This noise level is consistent with that predicted from bolometer thermal fluctuation (i.e. phonon) noise. Furthermore, the power spectral density is white over a range of frequencies down to ~ 100 mHz, which enables CMB mapping on large angular scales that constrain the physics of inflation. Additionally, we report cross-talk measurements that indicate a level below 0.3%, which is less than the level of cross-talk from multiplexed readout systems in deployed CMB imagers. These measurements demonstrate the µmux as a viable readout technique for future CMB imaging instruments.

  14. SQUID biosusceptometry in the measurement of hepatic iron

    International Nuclear Information System (INIS)

    Sheth, Sujit

    2003-01-01

    Individuals with primary or secondary abnormalities of iron metabolism, such as hereditary hemochromatosis and transfusional iron loading, may develop potentially lethal systemic iron overload. Over time, this excess iron is progressively deposited in the liver, heart, pancreas, and other organs, resulting in cirrhosis, heart disease, diabetes and other disorders. Unless treated, death usually results from cardiac failure. The amount of iron in the liver is the best indicator of the amount of iron in the whole body. At present, the only sure way to measure the amount of iron in the liver is to remove a sample of the liver by biopsy. Iron stored in the liver can be magnetized to a small degree when placed in a magnetic field. The amount of magnetization is measured by our instrument, called a superconducting quantum interference device (SQUID) susceptometer. In patients with iron overload, our previous studies have shown that magnetic measurements of liver iron in patients with iron overload are quantitatively equivalent to biochemical determinations on tissue obtained by biopsy. The safety, ease, rapidity, and comfort of magnetic measurements make frequent, serial studies technically feasible and practically acceptable to patients. (orig.)

  15. Automatic system for quantification and visualization of lung aeration on chest computed tomography images: the Lung Image System Analysis - LISA

    Energy Technology Data Exchange (ETDEWEB)

    Felix, John Hebert da Silva; Cortez, Paulo Cesar, E-mail: jhsfelix@gmail.co [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil). Dept. de Engenharia de Teleinformatica; Holanda, Marcelo Alcantara [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil). Hospital Universitario Walter Cantidio. Dept. de Medicina Clinica

    2010-12-15

    High Resolution Computed Tomography (HRCT) is the exam of choice for the diagnostic evaluation of lung parenchyma diseases. There is an increasing interest for computational systems able to automatically analyze the radiological densities of the lungs in CT images. The main objective of this study is to present a system for the automatic quantification and visualization of the lung aeration in HRCT images of different degrees of aeration, called Lung Image System Analysis (LISA). The secondary objective is to compare LISA to the Osiris system and also to specific algorithm lung segmentation (ALS), on the accuracy of the lungs segmentation. The LISA system automatically extracts the following image attributes: lungs perimeter, cross sectional area, volume, the radiological densities histograms, the mean lung density (MLD) in Hounsfield units (HU), the relative area of the lungs with voxels with density values lower than -950 HU (RA950) and the 15th percentile of the least density voxels (PERC15). Furthermore, LISA has a colored mask algorithm that applies pseudo-colors to the lung parenchyma according to the pre-defined radiological density chosen by the system user. The lungs segmentations of 102 images of 8 healthy volunteers and 141 images of 11 patients with Chronic Obstructive Pulmonary Disease (COPD) were compared on the accuracy and concordance among the three methods. The LISA was more effective on lungs segmentation than the other two methods. LISA's color mask tool improves the spatial visualization of the degrees of lung aeration and the various attributes of the image that can be extracted may help physicians and researchers to better assess lung aeration both quantitatively and qualitatively. LISA may have important clinical and research applications on the assessment of global and regional lung aeration and therefore deserves further developments and validation studies. (author)

  16. Automatic system for quantification and visualization of lung aeration on chest computed tomography images: the Lung Image System Analysis - LISA

    International Nuclear Information System (INIS)

    Felix, John Hebert da Silva; Cortez, Paulo Cesar; Holanda, Marcelo Alcantara

    2010-01-01

    High Resolution Computed Tomography (HRCT) is the exam of choice for the diagnostic evaluation of lung parenchyma diseases. There is an increasing interest for computational systems able to automatically analyze the radiological densities of the lungs in CT images. The main objective of this study is to present a system for the automatic quantification and visualization of the lung aeration in HRCT images of different degrees of aeration, called Lung Image System Analysis (LISA). The secondary objective is to compare LISA to the Osiris system and also to specific algorithm lung segmentation (ALS), on the accuracy of the lungs segmentation. The LISA system automatically extracts the following image attributes: lungs perimeter, cross sectional area, volume, the radiological densities histograms, the mean lung density (MLD) in Hounsfield units (HU), the relative area of the lungs with voxels with density values lower than -950 HU (RA950) and the 15th percentile of the least density voxels (PERC15). Furthermore, LISA has a colored mask algorithm that applies pseudo-colors to the lung parenchyma according to the pre-defined radiological density chosen by the system user. The lungs segmentations of 102 images of 8 healthy volunteers and 141 images of 11 patients with Chronic Obstructive Pulmonary Disease (COPD) were compared on the accuracy and concordance among the three methods. The LISA was more effective on lungs segmentation than the other two methods. LISA's color mask tool improves the spatial visualization of the degrees of lung aeration and the various attributes of the image that can be extracted may help physicians and researchers to better assess lung aeration both quantitatively and qualitatively. LISA may have important clinical and research applications on the assessment of global and regional lung aeration and therefore deserves further developments and validation studies. (author)

  17. High-resolution photon spectroscopy with a microwave-multiplexed 4-pixel transition edge sensor array

    Science.gov (United States)

    Guss, Paul; Rabin, Michael; Croce, Mark; Hoteling, Nathan; Schwellenbach, David; Kruschwitz, Craig; Mocko, Veronika; Mukhopadhyay, Sanjoy

    2017-09-01

    We demonstrate very high-resolution photon spectroscopy with a microwave-multiplexed 4-pixel transition edge sensor (TES) array. The readout circuit consists of superconducting microwave resonators coupled to radio frequency superconducting-quantum-interference devices (RF-SQUIDs) and transduces changes in input current to changes in phase of a microwave signal. We used a flux-ramp modulation to linearize the response and avoid low-frequency noise. The result is a very high-resolution photon spectroscopy with a microwave-multiplexed 4-pixel transition edge sensor array. We performed and validated a small-scale demonstration and test of all the components of our concept system, which encompassed microcalorimetry, microwave multiplexing, RF-SQUIDs, and software-defined radio (SDR). We shall display data we acquired in the first simultaneous combination of all key innovations in a 4-pixel demonstration, including microcalorimetry, microwave multiplexing, RF-SQUIDs, and SDR. We present the energy spectrum of a gadolinium-153 (153Gd) source we measured using our 4-pixel TES array and the RF-SQUID multiplexer. For each pixel, one can observe the two 97.4 and 103.2 keV photopeaks. We measured the 153Gd photon source with an achieved energy resolution of 70 eV, full width half maximum (FWHM) at 100 keV, and an equivalent readout system noise of 90 pA/pHz at the TES. This demonstration establishes a path for the readout of cryogenic x-ray and gamma ray sensor arrays with more elements and spectral resolving powers. We believe this project has improved capabilities and substantively advanced the science useful for missions such as nuclear forensics, emergency response, and treaty verification through the explored TES developments.

  18. Identifying Pelagic Habitat Hotspots of Neon Flying Squid in the Temperate Waters of the Central North Pacific.

    Science.gov (United States)

    Alabia, Irene D; Saitoh, Sei-Ichi; Mugo, Robinson; Igarashi, Hiromichi; Ishikawa, Yoichi; Usui, Norihisa; Kamachi, Masafumi; Awaji, Toshiyuki; Seito, Masaki

    2015-01-01

    We identified the pelagic habitat hotspots of the neon flying squid (Ommastrephes bartramii) in the central North Pacific from May to July and characterized the spatial patterns of squid aggregations in relation to oceanographic features such as mesoscale oceanic eddies and the Transition Zone Chlorophyll-a Front (TZCF). The data used for the habitat model construction and analyses were squid fishery information, remotely-sensed and numerical model-derived environmental data from May to July 1999-2010. Squid habitat hotspots were deduced from the monthly Maximum Entropy (MaxEnt) models and were identified as regions of persistent high suitable habitat across the 12-year period. The distribution of predicted squid habitat hotspots in central North Pacific revealed interesting spatial and temporal patterns likely linked with the presence and dynamics of oceanographic features in squid's putative foraging grounds from late spring to summer. From May to June, the inferred patches of squid habitat hotspots developed within the Kuroshio-Oyashio transition zone (KOTZ; 37-40°N) and further expanded north towards the subarctic frontal zone (SAFZ; 40-44°N) in July. The squid habitat hotspots within the KOTZ and areas west of the dateline (160°W-180°) were likely influenced and associated with the highly dynamic and transient oceanic eddies and could possibly account for lower squid suitable habitat persistence obtained from these regions. However, predicted squid habitat hotspots located in regions east of the dateline (180°-160°W) from June to July, showed predominantly higher squid habitat persistence presumably due to their proximity to the mean position of the seasonally-shifting TZCF and consequent utilization of the highly productive waters of the SAFZ.

  19. electrode array

    African Journals Online (AJOL)

    PROF EKWUEME

    A geoelectric investigation employing vertical electrical soundings (VES) using the Ajayi - Makinde Two-Electrode array and the ... arrangements used in electrical D.C. resistivity survey. These include ..... Refraction Tomography to Study the.

  20. Opportunistic acoustic recordings of (potential) orangeback flying squid Sthenoteuthis pteropus in the Central Eastern Atlantic

    Science.gov (United States)

    Peña, Marian; Villanueva, Roger; Escánez, Alejandro; Ariza, Alejandro

    2018-03-01

    Squids are fast swimmers that are difficult to catch by nets and to record with echosounders in the open ocean. A rare detection of orangeback flying squid Sthenoteuthis pteropus in the Central Eastern Atlantic Ocean off the coast of Senegal was accomplished during the MAFIA oceanographic survey carried out between Brazil and the Canary Islands in April 2015. Although net sampling did not yield any subadult or adult individuals, dozens were visually detected from the vessel jumping out of the water at night and displaying their characteristic dorsal photophore patch. A few squids were caught with fishing lines and identified at the species level. The acoustic echograms revealed distinctive previously unobserved acoustic echotraces that seemed to be caused by those squids, which were the only new species detected at that station (over a bottom depth ranging from 4010 to 5215 m, between 10° 45‧ N 22° 41‧ W and 10° 53‧ N 22° 40‧ W). The acoustic response and swimming behaviour shown by those echotraces reinforced this hypothesis. The (potentially) squid recordings dove rapidly (0.19 m/s to 0.48 m/s) from around 10 m below the mesopelagic fish layer, which had migrated to the subsurface at night (35 m depth), to depths of 70-95 m, and swam upward, apparently attacking fish from below. The morning squid migration to deeper waters (250-300 m) was also recorded acoustically. Downward movements of squid swimming at speeds of 0.22 m/s were calculated from the echogram, while the mesopelagic migrating fish swam at 0.27 m/s reaching 250 m depth. Sv120 - Sv38 averaged 2.7 ± 3.2 dB for the squid echotraces while the mesopelagic layer showed values of -8.8 ± 0.9 dB. These ranges agreed with values in the literature and from theoretical models. This study provides more insight into the migrating behaviour of oceanic squids, a species group that is poorly represented in the acoustic literature due to challenges in studying them.

  1. Mobile HTS-SQUID NDE system with robot arm and active shielding using fluxgate

    Energy Technology Data Exchange (ETDEWEB)

    Hatsukade, Y. [Department of Ecological Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan)], E-mail: hatukade@eco.tut.ac.jp; Yotsugi, K.; Tanaka, S. [Department of Ecological Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan)

    2008-09-15

    A robot-arm-based mobile HTS-SQUID NDE system was developed for inspection of advanced structures such as hydrogen fuel cell tanks. In order to realize stable operation of HTS-SQUID exposed in Earth's field and robot arm's noise without flux trapping, flux jumping and unlocking during motion, a new active magnetic shielding (AMS) technique using fluxgate was introduced. The high sensitive fluxgate, which could measure magnetic field of up to several 10 {mu}T, was mounted near an HTS-SQUID gradiometer on the robot arm to measure the ambient noise and feed back its output to a compensation coil, which surrounded both SQUID and fluxgate to cancel the ambient noise around them. The AMS technique successfully enabled the HTS-SQUID gradiometer to be moved at 10 mm/s by the robot arm in unshielded environment without flux trapping, jumping and unlocking. Detection of hidden slots in multi-layer composite-metal structures imitating the fuel cell tank was demonstrated.

  2. Vestigial phragmocone in the gladius points to a deepwater origin of squid (Mollusca: Cephalopoda)

    Science.gov (United States)

    Arkhipkin, Alexander I.; Bizikov, Vyacheslav A.; Fuchs, Dirk

    2012-03-01

    The microstructure of the gladius cone was investigated in six species of nektonic squid: shallow-water Loligo gahi (Loliginidae), pelagic eurybathic Illex argentinus, Todarodes pacificus, Dosidicus gigas (Ommastrephidae), and deepwater Onykia ingens (Onychoteuthidae) and Gonatus antarcticus (Gonatidae) using state-of-the-art microscopy. Apart from L. gahi, all other species had septa-like layers in the gladius cone, which for the first time were investigated in detail and compared with those in extinct Cretaceous belemnites Hibolithes sp. and Pachyteuthis sp., and spirulid Cyrtobelus sp. It was found that the organic layers of the gladius cone in recent squid can be homologized with the organic components of the shell in fossil phragmocone-bearing coleoids. The septa-like layers in modern gladius cones therefore represent a vestigial phragmocone composed of organic septal rudiments of the ancestral phragmocone that has lost the siphuncle and gas-filled chambers. The well-developed rostrum in onychoteuthids and small rostrum of the gladius in ommastrephids and gonatids can be seen as homologous with the belemnoid rostrum, which may indicate a close phylogenetic relationship between belemnites and at least some squid. Possible evolutionary pathways of the reduction of the functional phragmocone in squid ancestors are discussed. Several features such as the loss of shell calcification, deep water speciation, and the structure of the equilibrium organ point to a deep-water origin of squids.

  3. Development of Nb nanoSQUIDs based on SNS junctions for operation in high magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Morosh, Viacheslav; Kieler, Oliver; Weimann, Thomas; Zorin, Alexander [Physikalisch-Technische Bundesanstalt (PTB), Braunschweig (Germany); Mueller, Benedikt; Martinez-Perez, Maria Jose; Kleiner, Reinhold; Koelle, Dieter [Physikalisches Institut and Center for Quantum Science in LISA+, Universitaet Tuebingen (Germany)

    2016-07-01

    Investigation of the magnetization reversal of single magnetic nanoparticles requires SQUIDs with high spatial resolution, high spin sensitivity (a few Bohr magneton μ{sub B}) and at the same time sufficient stability in high magnetic fields. We fabricated dc nanoSQUIDs comprising overdamped SNS sandwich-type (Nb/HfTi/Nb) Josephson junctions using optimized technology based on combination of electron beam lithography and chemical-mechanical polishing. Our nanoSQUIDs have Josephson junctions with lateral dimensions ≤ 150 nm x 150 nm, effective loop areas < 0.05 μm{sup 2} and the distance between the Josephson junctions ≤ 100 nm. The feeding strip lines of the width ≤ 200 nm have been realized. The nanoSQUIDs have shown stable operation in external magnetic fields at least up to 250 mT. Sufficiently low level of flux noise resulting in spin sensitivity of few tens μ{sub B}/Hz{sup 1/2} has been demonstrated. A further reduction of the nanoSQUID size using our technology is possible.

  4. SQUID magnetometer using sensitivity correction signal for non-magnetic metal contaminants detection

    Energy Technology Data Exchange (ETDEWEB)

    Yagi, Toshifumi, E-mail: sakuta.k@usp.ac.jp; Ohashi, Masaharu; Sakuta, Ken

    2016-11-15

    Highlights: • A high-frequency excitation is necessary to detect nonmagnetic metals using SQUID. • It is possible to detect a high-frequency magnetic field using the open loop technique. • Open loop operation leads to a change in the conversion factor. • Conversion between voltage and magnetic field for open loop operation are examined. - Abstract: Measurement methods with SQUID can accurately detect small magnetic metal contaminants based on their magnetic remanence. But, a high-frequency excitation is necessary to detect nonmagnetic metals, on the base of contrasts in electric conductivity. In this work, an open loop technique is introduced to facilitate this. The SQUID is negative feedback controlled (flux locked loop (FLL) operation) for the low frequency range, which includes significant noise due to the movement of the magnetic body or the change of the ambient magnetic field composed of the geomagnetic field and technical signals, and it operates in an open loop configuration for the high frequency range. When using the open loop technique, negative feedback is not applied to the high frequency range. Consequently, the V–Φ characteristic changes due to various causes, which leads to variations in the conversion factor between the SQUID output voltage and the magnetic field. In this study, conversion techniques for the magnetic field for open loop operation of SQUID in the high frequency range are examined.

  5. NANO-SQUIDs based on niobium Dayem bridges for nanoscale applications

    Energy Technology Data Exchange (ETDEWEB)

    Granata, C; Esposito, E; Nappi, C; Ruggiero, B; Russo, M [Istituto di Cibernetica ' E. Caianiello' del Consiglio Nazionale delle Ricerche, 80078 Pozzuoli (Napoli) (Italy); Vettoliere, A; Walke, P [Also Universita degli Studi di Napoli ' Federico II' , Napoli (Italy); Silvestrini, P, E-mail: c.granata@cib.na.cnr.i [Dipartimento di Ingegneria dell' Informazione, Seconda Universita degli Studi di Napoli, Aversa(Caserta) (Italy)

    2010-06-01

    We report on the design, the fabrication and the performance of an integrated magnetic nano-sensor based on niobium dc-SQUID (Superconducting QUantum Interference Device) for nanoscale applications is presented. The nano-sensors are based on nanometric niobium constrictions (Dayem bridges) inserted in a square loop having a side length of 200 nm. Measurements of voltage-flux characteristic, flux to voltage transfer factor and noise performances are reported. In small signal mode, the sensors have shown a magnetic flux noise spectral density of 1.5 {mu}{Phi}{sub 0}/Hz{sup 1/2} corresponding to a spin sensitivity in unit of Bohr magneton of 60 spin/Hz{sup 1/2}. Supercurrent decay measurements of these devices are also reported. Such measurements provide useful information for applications which employ the SQUID as a trigger where the sensor works on the zero voltage state. The experimental data, have shown an intrinsic current fluctuation less than 0.2% of the critical current at liquid helium temperature, corresponding to an intrinsic sensor magnetic flux resolution of a few m{Phi}{sub 0}. In view of the nano-SQUID employments in the detection of small spin populations, the authors calculated the spin sensitivity and the magnetic response relative to the single spin, as a function of its position within the SQUID hole. The results show that the SQUID response depends strongly on the spin position.

  6. RF SQUID in the nonhysteretic regime with k2Ql>1

    International Nuclear Information System (INIS)

    Dmitrenko, I.M.; Tsoi, G.M.; Shnyrkov, V.I.; Kartsovnik, V.V.

    1982-01-01

    Experimental measurements of current-voltage, current-phase, amplitude-frequency, phase-frequency, and signal characteristics of an rf SQUID operating at a frequency of 30 MHz in the nonhysteretic regime (1 = 2πL 0 I 0 /phi/sub o/ 2 Ql>1. Here I 0 is the critical current of the weak link, L 0 is the SQUID ring inductance, k is the coefficient of coupling of the SQUID ring to a resonant tank circuit of quality Q, and phi 0 is the magnetic flux quantum. A numerical analysis of the above characteristics for all relevant parameter values close to those occurring under experimental conditions was performed for qualitative comparison with theory. The main difference from the traditional nonhysteretic regime of SQUID operation (k 2 Q1 12 V/Wb for the single-valued region of the signal characteristics. The results suggest that considerable improvement of rf SQUID resolution is possible in the regime k 2 Ql>1

  7. SQUID magnetometer using sensitivity correction signal for non-magnetic metal contaminants detection

    International Nuclear Information System (INIS)

    Yagi, Toshifumi; Ohashi, Masaharu; Sakuta, Ken

    2016-01-01

    Highlights: • A high-frequency excitation is necessary to detect nonmagnetic metals using SQUID. • It is possible to detect a high-frequency magnetic field using the open loop technique. • Open loop operation leads to a change in the conversion factor. • Conversion between voltage and magnetic field for open loop operation are examined. - Abstract: Measurement methods with SQUID can accurately detect small magnetic metal contaminants based on their magnetic remanence. But, a high-frequency excitation is necessary to detect nonmagnetic metals, on the base of contrasts in electric conductivity. In this work, an open loop technique is introduced to facilitate this. The SQUID is negative feedback controlled (flux locked loop (FLL) operation) for the low frequency range, which includes significant noise due to the movement of the magnetic body or the change of the ambient magnetic field composed of the geomagnetic field and technical signals, and it operates in an open loop configuration for the high frequency range. When using the open loop technique, negative feedback is not applied to the high frequency range. Consequently, the V–Φ characteristic changes due to various causes, which leads to variations in the conversion factor between the SQUID output voltage and the magnetic field. In this study, conversion techniques for the magnetic field for open loop operation of SQUID in the high frequency range are examined.

  8. Non-destructive inspection using HTS-SQUID on aluminum liner covered by CFRP

    International Nuclear Information System (INIS)

    Hatsukade, Y.; Yotsugi, K.; Sakaguchi, Y.; Tanaka, S.

    2007-01-01

    An eddy-current-based SQUID non-destructive inspection (NDI) system to detect deep-lying cracks in multi-layer composite-Al vessels was developed taking advantage of the uncontested sensitivity of HTS-SQUID in low-frequency range. An HTS-SQUID gradiometer was mounted in a pulse tube cryocooler. A pair of differential coils with C-shaped ferrite cores was employed to induce an enhanced eddy current in an Al vessel wrapped in a carbon fiber reinforced plastic (CFRP) cover. Ellipsoidal dome-shaped Al liners containing through cracks, which were made by pressure cycle tests, in the CFRP covers with total thickness of 6 mm (CFPR 3 mm, and Al 3 mm) were inspected by the system. While inducing eddy currents in the vessels with excitation fields at 100 Hz or 7 kHz, the vessels were rotated under the HTS-SQUID. Above the cracks, anomalous signals due to the cracks were clearly detected at both frequencies. These results suggested the SQUID-NDI technique would be a possible candidate for inspection of high-pressure multi-layer composite-Al vessels

  9. Non-destructive inspection using HTS-SQUID on aluminum liner covered by CFRP

    Energy Technology Data Exchange (ETDEWEB)

    Hatsukade, Y. [Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan)], E-mail: hatukade@eco.tut.ac.jp; Yotsugi, K. [Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan); Sakaguchi, Y. [SAMTECH Corporation, 1000-18 Enmyo-cho, Kashiwara City, Osaka 582-0027 (Japan); Tanaka, S. [Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan)

    2007-10-01

    An eddy-current-based SQUID non-destructive inspection (NDI) system to detect deep-lying cracks in multi-layer composite-Al vessels was developed taking advantage of the uncontested sensitivity of HTS-SQUID in low-frequency range. An HTS-SQUID gradiometer was mounted in a pulse tube cryocooler. A pair of differential coils with C-shaped ferrite cores was employed to induce an enhanced eddy current in an Al vessel wrapped in a carbon fiber reinforced plastic (CFRP) cover. Ellipsoidal dome-shaped Al liners containing through cracks, which were made by pressure cycle tests, in the CFRP covers with total thickness of 6 mm (CFPR 3 mm, and Al 3 mm) were inspected by the system. While inducing eddy currents in the vessels with excitation fields at 100 Hz or 7 kHz, the vessels were rotated under the HTS-SQUID. Above the cracks, anomalous signals due to the cracks were clearly detected at both frequencies. These results suggested the SQUID-NDI technique would be a possible candidate for inspection of high-pressure multi-layer composite-Al vessels.

  10. Non-linear quantization error reduction for the temperature measurement subsystem on-board LISA Pathfinder

    Science.gov (United States)

    Sanjuan, J.; Nofrarias, M.

    2018-04-01

    Laser Interferometer Space Antenna (LISA) Pathfinder is a mission to test the technology enabling gravitational wave detection in space and to demonstrate that sub-femto-g free fall levels are possible. To do so, the distance between two free falling test masses is measured to unprecedented sensitivity by means of laser interferometry. Temperature fluctuations are one of the noise sources limiting the free fall accuracy and the interferometer performance and need to be known at the ˜10 μK Hz-1/2 level in the sub-millihertz frequency range in order to validate the noise models for the future space-based gravitational wave detector LISA. The temperature measurement subsystem on LISA Pathfinder is in charge of monitoring the thermal environment at key locations with noise levels of 7.5 μK Hz-1/2 at the sub-millihertz. However, its performance worsens by one to two orders of magnitude when slowly changing temperatures are measured due to errors introduced by analog-to-digital converter non-linearities. In this paper, we present a method to reduce this effect by data post-processing. The method is applied to experimental data available from on-ground validation tests to demonstrate its performance and the potential benefit for in-flight data. The analog-to-digital converter effects are reduced by a factor between three and six in the frequencies where the errors play an important role. An average 2.7 fold noise reduction is demonstrated in the 0.3 mHz-2 mHz band.

  11. Modulator noise suppression in the LISA time-delay interferometric combinations

    International Nuclear Information System (INIS)

    Tinto, Massimo; Armstrong, J W; Estabrook, Frank B

    2008-01-01

    Laser Interferometer Space Antenna (LISA) is a mission to detect and study low-frequency cosmic gravitational radiation through its influence on the phases of six modulated laser beams exchanged between three remote spacecraft. We previously showed how the measurements of some 18 time series of relative frequency or phase shifts could be combined (1) to cancel the phase noise of the lasers, (2) to cancel the Doppler fluctuations due to non-inertial motions of the six optical benches and (3) to remove the phase noise of the onboard reference oscillators required to track the photodetector fringes, all the while preserving signals from passing gravitational waves. Here we analyze the effect of the additional noise due to the optical modulators used for removing the phase fluctuations of the onboard reference oscillators. We use the recently measured noise spectrum of an individual modulator (Klipstein et al 2006 Proc. 6th Int. LISA Symp. (Greenbelt, MA) (AIP Conf. Proc. vol 873) ed S M Merkowitz and J C Livas pp 19-23) to quantify the contribution of modulator noise to the first and second-generation time-delay interferometric (TDI) combinations as a function of the modulation frequency. We show that modulator noise can be made smaller than the expected proof-mass acceleration and optical-path noises if the modulation frequencies are larger than ∼682 MHz in the case of the unequal-arm Michelson TDI combination X 1 , ∼ 1.08 GHz for the Sagnac TDI combination α 1 , and ∼706 MHz for the symmetrical Sagnac TDI combination ζ 1 . These modulation frequencies are substantially smaller than previously estimated and may lead to less stringent requirements on the LISA's oscillator noise calibration subsystem. The measurements in Klipstein et al were performed in a laboratory experiment for a range of modulation frequencies, but we emphasize that, for the reference oscillator noise calibration algorithm to work, the modulation frequencies must be equal to the

  12. Fabrication of prototype imaging arrays for SCUBA-2

    International Nuclear Information System (INIS)

    Hilton, G.C.; Beall, J.A.; Doriese, W.B.; Duncan, W.D.; Ferreira, L.S.; Irwin, K.D.; Reintsema, C.D.; Ullom, J.N.; Vale, L.R.; Xu, Y.; Zink, B.L.; Parkes, W.; Bunting, A.S.; Dunare, C.C.; Gundlach, A.M.; Stevenson, J.T.M.; Walton, A.J.; Schulte, E.; Corrales, E.; Sienicki, J.P.; Bintley, Dan; Ade, P.A.R.; Sudiwala, Rashmi V.; Woodcraft, Adam L.; Halpern, Mark; Holland, W.; Audley, M.D.; MacIntosh, M.

    2006-01-01

    Prototype imaging subarrays for SCUBA-2 (the Submillimeter Common-User Bolometer Array) have been fabricated and tested. The pixel count (1280) of these wafer-scale imagers is significantly larger than any other low-temperature detectors produced to date, and represents a major step forward for the low-temperature detector community. These transition-edge-sensor (TES) based imagers utilize several innovations including in-focal-plane superconducting quantum intereference device (SQUID) multiplexers, micromachined Si block absorbers, and superconducting wafer hybridization. In this paper, we review the fabrication processes developed for these imagers and present recent optical data from a prototype imaging subarray

  13. Massive Black Hole Mergers: Can We "See" what LISA will "Hear"?

    Science.gov (United States)

    Centrella, Joan

    2010-01-01

    The final merger of massive black holes produces strong gravitational radiation that can be detected by the space-borne LISA. If the black hole merger takes place in the presence of gas and magnetic fields, various types of electromagnetic signals may also be produced. Modeling such electromagnetic counterparts of the final merger requires evolving the behavior of both gas and fields in the strong-field regions around the black holes. We will review current efforts to simulate these systems, and discuss possibilities for observing the electromagnetic signals they produce.

  14. LISA - a powerful program package for LIstmode and Spectral data Analysis

    International Nuclear Information System (INIS)

    Oberstedt, A.; Hambsch, F.J.

    1994-01-01

    LISA is a graphical program package which enables both off-line listmode and spectral data evaluation as well as on-line monitoring while multi-parameter experiments are running. It can be executed on every computer with a UNIX operating system and an X-WINDOW environment, running PV-WAVE from Visual Numerics Incorporation. This package is basically written in the language PV-WAVE CL, but integration of procedures written in the C-language and execution of UNIX shell commands lead to an additional increase of performance. (orig.)

  15. On-orbit alignment and diagnostics for the LISA Technology Package

    International Nuclear Information System (INIS)

    MarIn, A F GarcIa; Wand, V; Steier, F; Cervantes, F Guzman; Bogenstahl, J; Jennrich, O; Heinzel, G; Danzmann, K

    2006-01-01

    This paper presents a procedure to perform fully autonomous on-orbit alignment of the interferometer on board the LISA Technology Package (LTP). LTP comprises two free-floating test masses as inertial sensors that additionally serve as end mirrors of a set of interferometers. From the output signals of the interferometers, a subset has been selected to obtain alignment information of the test masses. Based on these signals, an alignment procedure was developed and successfully tested on the engineering model of the optical bench. Furthermore, operation procedures for the characterization of critical on-orbit properties of the optical metrology system (e.g. fibre noise) have been established

  16. After-dinner speech: the path of LISA to become ‘L3’

    Science.gov (United States)

    Huber, M. C. E.

    2017-05-01

    We describe the state of fundamental-physics experiments in space in the mid 1980s on both sides of the Atlantic, and then follow the development of this field within ESA’s Scientific Programme. The special case of LISA — a fundamental physics experiment in space also supported by astronomers, and now, following the ground-based detection of gravitational waves, the means to extend the observable spectrum of such waves towards lower frequencies and long-lasting signals — is then followed in its rise to become the ‘Large Project L3’ of ESA.

  17. Observing extreme-mass-ratio inspirals with eLISA/NGO

    OpenAIRE

    Gair, Jonathan R; Porter, Edward K

    2012-01-01

    The extreme-mass-ratio inspirals (EMRIs) of stellar mass compact objects into massive black holes in the centres of galaxies are an important source of low-frequency gravitational waves for space-based detectors. We discuss the prospects for detecting these sources with the evolved Laser Interferometer Space Antenna (eLISA), recently proposed as an ESA mission candidate under the name NGO. We show that NGO could observe a few tens of EMRIs over its two year mission lifetime at redshifts z < 0...

  18. LISA. A code for safety assessment in nuclear waste disposals program description and user guide

    International Nuclear Information System (INIS)

    Saltelli, A.; Bertozzi, G.; Stanners, D.A.

    1984-01-01

    The code LISA (Long term Isolation Safety Assessment), developed at the Joint Research Centre, Ispra is a useful tool in the analysis of the hazard due to the disposal of nuclear waste in geological formations. The risk linked to preestablished release scenarios is assessed by the code in terms of dose rate to a maximum exposed individual. The various submodels in the code simulate the system of barriers -both natural and man made- which are interposed between the contaminants and man. After a description of the code features a guide for the user is supplied and then a test case is presented

  19. Effects of different eLISA-like configurations on massive black hole parameter estimation

    Science.gov (United States)

    Porter, Edward K.

    2015-09-01

    As the theme for the future L3 Cosmic Vision mission, ESA has recently chosen the "Gravitational Wave Universe." Within this program, a mission concept called eLISA has been proposed. This observatory has a current initial configuration consisting of four laser links between the three satellites, which are separated by a distance of one million kilometers, constructing a single-channel Michelson interferometer. However, the final configuration for the observatory will not be fixed until the end of this decade. With this in mind, we investigate the effect of different eLISA-like configurations on massive black hole detections. This work compares the results of a Bayesian inference study of 120 massive black hole binaries out to a redshift of z ˜13 for a 106 km arm length eLISA with four and six links, as well as a 2 ×106 km arm length observatory with four links. We demonstrate that the original eLISA configuration should allow us to recover the luminosity distance of the source with an error of less than 10% out to a redshift of z ˜4 , and a sky error box of Δ Ω ≤102 deg2 out to z ˜0.1 . In contrast, both alternative configurations suggest that we should be able to conduct the same parameter recovery with errors of less than 10% in luminosity distance out to z ˜12 and Δ Ω ≤102 deg2 out to z ˜0.4 . Using the information from these studies, we also infer that if we were able to construct a 2 Gm, six-link detector, the above values would shift to z ˜20 for luminosity distance and z ˜0.9 for sky error. While the final configuration will also be dependent on both technological and financial considerations, our study suggests that increasing the size of a two-arm detector is a viable alternative to the inclusion of a third arm in a smaller detector. More importantly, this work further suggests no clear scientific loss between either choice.

  20. Constraining early and interacting dark energy with gravitational wave standard sirens: the potential of the eLISA mission

    International Nuclear Information System (INIS)

    Caprini, Chiara; Tamanini, Nicola

    2016-01-01

    We perform a forecast analysis of the capability of the eLISA space-based interferometer to constrain models of early and interacting dark energy using gravitational wave standard sirens. We employ simulated catalogues of standard sirens given by merging massive black hole binaries visible by eLISA, with an electromagnetic counterpart detectable by future telescopes. We consider three-arms mission designs with arm length of 1, 2 and 5 million km, 5 years of mission duration and the best-level low frequency noise as recently tested by the LISA Pathfinder. Standard sirens with eLISA give access to an intermediate range of redshift 1 ∼< z ∼< 8, and can therefore provide competitive constraints on models where the onset of the deviation from ΛCDM (i.e. the epoch when early dark energy starts to be non-negligible, or when the interaction with dark matter begins) occurs relatively late, at z ∼< 6. If instead early or interacting dark energy is relevant already in the pre-recombination era, current cosmological probes (especially the cosmic microwave background) are more efficient than eLISA in constraining these models, except possibly in the interacting dark energy model if the energy exchange is proportional to the energy density of dark energy.

  1. Thermodynamics of a closed-cycle gas flow system for cooling a HTc dc-SQUID magnetometer

    NARCIS (Netherlands)

    van den Bosch, P.J.; van den Bosch, P.J.; ter Brake, Hermanus J.M.; van den Eijkel, G.C.; Boelens, J.P.; Holland, Herman J.; Verberne, J.F.C.; Rogalla, Horst

    1994-01-01

    A multichannel high-Tc dc-SQUID based heart-magnetometer is currently under development in our laboratory. The system is cooled by a cooler that, due to its magnetic interference, has to be separated from the SQUID unit. In the present prototype system a closed-cycle gas flow was chosen as the

  2. 76 FR 3044 - Fisheries of the Exclusive Economic Zone Off Alaska; Sculpins, Sharks, Squid, and Octopus in the...

    Science.gov (United States)

    2011-01-19

    ..., Squid, and Octopus in the Gulf of Alaska AGENCY: National Marine Fisheries Service (NMFS), National... prohibiting directed fishing for sculpins, sharks, squid, and octopus in the Gulf of Alaska (GOA). This action..., and octopus in the GOA. DATES: Effective 1200 hrs, Alaska local time (A.l.t.), January 13, 2011...

  3. The male reproductive strategy of a deep-sea squid : sperm allocation, continuous production, and long-term storage of spermatophores in Histioteuthis miranda

    NARCIS (Netherlands)

    Hoving, Hendrik Jan T.; Lipinski, Marek R.; Dam, Lammertjan

    2010-01-01

    Squid are semelparous organisms. Much of what we know about squid reproduction relates to females, because few studies have addressed males and, although males are similarly challenged by semelparity, it remains virtually unknown what tactics squid have evolved to allocate sperm to spermatophores.

  4. Research on Intelligent Control System of DC SQUID Magnetometer Parameters for Multi-channel System

    Science.gov (United States)

    Chen, Hua; Yang, Kang; Lu, Li; Kong, Xiangyan; Wang, Hai; Wu, Jun; Wang, Yongliang

    2018-03-01

    In a multi-channel SQUID measurement system, adjusting device parameters to optimal condition for all channels is time-consuming. In this paper, an intelligent control system is presented to determine the optimal working point of devices which is automatic and more efficient comparing to the manual one. An optimal working point searching algorithm is introduced as the core component of the control system. In this algorithm, the bias voltage V_bias is step scanned to obtain the maximal value of the peak-to-peak current value I_pp of the SQUID magnetometer modulation curve. We choose this point as the optimal one. Using the above control system, more than 30 weakly damped SQUID magnetometers with area of 5 × 5 mm^2 or 10 × 10 mm^2 are adjusted and a 36-channel magnetocardiography system perfectly worked in a magnetically shielded room. The average white flux noise is 15 μΦ_0/Hz^{1/2}.

  5. Second order gradiometer and dc SQUID integrated on a planar substrate

    Science.gov (United States)

    van Nieuwenhuyzen, G. J.; de Waal, V. J.

    1985-02-01

    An integrated system of a thin-film niobium dc superconducting quantum interference device (SQUID) and a second order gradiometer on a planar substrate is described. The system consists of a dc SQUID with eight loops in parallel, each sensitive to the second derivative ∂2Bz/∂x2 of the magnetic field. The calculated SQUID inductance is 1.3 nH. With an overall size of 16×16.5 mm2 a sensitivity of 1.5×10-9 Tm-2 Hz-1/2 is obtained. The measured transfer function for uniform fields perpendicular to the plane of the gradiometer is 2.1×10-7 T Φ-10.

  6. Second order gradiometer and dc SQUID integrated on a planar substrate

    Energy Technology Data Exchange (ETDEWEB)

    van Nieuwenhuyzen, G.J.; de Waal, V.J.

    1985-02-15

    An integrated system of a thin-film niobium dc superconducting quantum interference device (SQUID) and a second order gradiometer on a planar substrate is described. The system consists of a dc SQUID with eight loops in parallel, each sensitive to the second derivative partial/sup 2/B/sub z//partialx/sup 2/ of the magnetic field. The calculated SQUID inductance is 1.3 nH. With an overall size of 16 x 16.5 mm/sup 2/ a sensitivity of 1.5 x 10/sup -9/ Tm/sup -2/ Hz/sup -1//sup ///sup 2/ is obtained. The measured transfer function for uniform fields perpendicular to the plane of the gradiometer is 2.1 x 10/sup -7/ T Phi/sup -1//sub 0/.

  7. Routine clinical heart examinations using SQUID magnetocardiography at University of Tsukuba Hospital

    Science.gov (United States)

    Inaba, T.; Nakazawa, Y.; Yoshida, K.; Kato, Y.; Hattori, A.; Kimura, T.; Hoshi, T.; Ishizu, T.; Seo, Y.; Sato, A.; Sekiguchi, Y.; Nogami, A.; Watanabe, S.; Horigome, H.; Kawakami, Y.; Aonuma, K.

    2017-11-01

    A 64-channel Nb-based DC-SQUID magnetocardiography (MCG) system was installed at the University of Tsukuba Hospital (UTH) in March 2007 after obtaining Japanese pharmaceutical approval and insurance reimbursement approval. In the period between 2008 and 2016, the total number of patients was 10 085. The heart diseases diagnosed in fetuses as well as adults are mainly atrial arrhythmia, abnormal repolarization, ventricular arrhythmia, and fetal arrhythmia. In most cases of insufficient diagnostic accuracy with electrocardiography, SQUID MCG precisely revealed these heart diseases as an abnormal electrical current distribution. Based on success in routine examinations, SQUID MCG is now an indispensable clinical instrument with diagnostic software tuned up during routine use at UTH.

  8. A SQUID magnetometry system for a cryogenic neutron electric dipole moment experiment

    Energy Technology Data Exchange (ETDEWEB)

    Henry, S., E-mail: s.henry@physics.ox.ac.uk; Clarke, C.; Cottle, A.; Lynch, A.; Pipe, M.

    2014-11-01

    Precision magnetometry is an essential component of any neutron electric dipole moment experiment in order to correct shifts in the neutron precession frequency due to changes in the magnetic field. We have developed a magnetometry system using 12 SQUID sensors, designed to operate in 0.5 K superfluid helium. The pick-up loops located near the neutron cell are connected to the SQUID sensors by ∼2 m twisted wire pairs. The SQUID readout cables are run via an intermediate stage at 4.2 K. The system has been installed and tested in the cryoEDM apparatus at the ILL, Grenoble, and used to characterise the magnetic environment. Further tests in a suitable low noise environment confirm it meets our requirements.

  9. Squid measurement of the Verwey transition on epitaxial (1 0 0) magnetite thin films

    International Nuclear Information System (INIS)

    Dediu, V.; Arisi, E.; Bergenti, I.; Riminucci, A.; Solzi, M.; Pernechele, C.; Natali, M.

    2007-01-01

    We report results on epitaxial magnetite (Fe 3 O 4 ) thin films grown by electron beam ablation on (1 0 0) MgAl 2 O 4 substrates. At 120 K magnetite undergoes a structural and electronic transition, the so-called Verwey transition, at which magnetic and conducting properties of the material change. We observed the Verwey transition on epitaxial films with a thickness of 50 nm by comparing zero-field cooling (ZFC) and field cooling (FC) curves measured with a superconducting quantum interference device (SQUID) magnetometer. Observation of the Verwey transition by SQUID measurements in the films is sign of their high crystalline quality. Room temperature ferromagnetism has also been found by magneto-optical Kerr rotation (MOKE) and confirmed by SQUID measurements, with a hysteresis loop showing a coercive field of hundreds of Oe

  10. Direct readout flux locked loop circuit with automatic tuning of bias current and bias flux for high-Tc SQUID

    International Nuclear Information System (INIS)

    Hirano, T.; Nagaishi, T.; Itozaki, H.

    1999-01-01

    Measurement of high-frequency magnetic signals has been required from some SQUID applications. We fabricated a high-T c SQUID magnetic sensor system that can treat high-frequency signals. This system is composed of a SQUID, a preamplifier circuit, a flux locked loop (FLL) circuit with I/O and a personal computer and a PC card. We used the FLL circuit with no modulation to treat the high-frequency signal and to simplify the circuit. This system can treat a signal from dc to 1 MHz. All the sequence from tuning the SQUID to data acquisition can be done by a personal computer. This system successfully realized easy operation of SQUID measurement. (author)

  11. Effect of thermal processing and canning on cadmium and lead levels in California market squid: the role of metallothioneins.

    Science.gov (United States)

    Galitsopoulou, A; Georgantelis, D; Kontominas, M G

    2013-01-01

    The effects of two common seafood preparation practices (roasting and industrial canning) on the heavy metal content--cadmium (Cd) and lead (Pb)--of various tissues of California market squid were studied. Emphasis was placed on the role of metallothioneins (MT) in Cd and Pb behaviour during processing. Cd and Pb analysis was conducted by a Zeeman GTA-AAS atomic absorption spectrometry system; MT analysis was performed by a mercury saturation assay. Results showed that Cd levels in the mantle and whole squid were considerably affected by both processing practices, reaching a 240% increase in mantle and a 40% increase in whole squid. Interestingly, Cd behaviour was associated with MT changes during squid processing. On the other hand, Pb content was not affected from either processing or associated with MT content in the raw or processed squid. Therefore, processing operations may affect Cd and Pb content differently due to the specific metal bioaccumulation and chemical features of each heavy metal type.

  12. Non-destructive testing (NDT) of metal cracks using a high Tc rf-SQUID and eddy current method

    Energy Technology Data Exchange (ETDEWEB)

    Lu, D.F.; Fan, C.; Ruan, J.Z. [Midwest Superconductivity Inc., Lawrence, KS (United States)] [and others

    1994-12-31

    A SQUID is the most sensitive device to detect change in magnetic field. A non-destructive testing (NDT) device using high temperature SQUIDs and eddy current method will be much more sensitive than those currently used eddy current systems, yet much cheaper than one with low temperature SQUIDs. In this paper, we present our study of such a NDT device using a high temperature superconducting rf-SQUID as a gradiometer sensor. The result clearly demonstrates the expected sensitivity of the system, and indicates the feasibility of building a portable HTS SQUID NDT device with the help from cryocooler industry. Such a NDT device will have a significant impact on metal corrosion or crack detection technology.

  13. Trophic relationships between the jumbo squid (Dosidicus gigas and the lightfish (Vinciguerria lucetia in the Humboldt Current System off Peru

    Directory of Open Access Journals (Sweden)

    Rigoberto Rosas-Luis

    2011-04-01

    Full Text Available Acoustic surveys for assessing the biomass and distribution of the jumbo squid (Dosidicus gigas and the lightfish (Vinciguerria lucetia were carried out in the Humboldt Current System of Peru in 2007 and 2008. At the same time, 937 jumbo squid were caught and their stomach contents analyzed. The diet of the jumbo squid was dominated by mesopelagic fish. The first component of their fish diet was V. lucetia and the second component was the myctophid fish Diogenichthys laternatus. Acoustic biomass estimates of these species show that V. lucetia is an important component in aggregative structures in the Humboldt Current System of Peru and its distribution and movements are closely related to the migratory movements of the jumbo squid. The trophic relationship observed between D. gigas and V. lucetia promotes an increase in jumbo squid biomass and, has a positive trophic effect on the ocean ecosystem.

  14. Non-destructive testing (NDT) of metal cracks using a high Tc rf-SQUID and eddy current method

    International Nuclear Information System (INIS)

    Lu, D.F.; Fan, C.; Ruan, J.Z.

    1994-01-01

    A SQUID is the most sensitive device to detect change in magnetic field. A non-destructive testing (NDT) device using high temperature SQUIDs and eddy current method will be much more sensitive than those currently used eddy current systems, yet much cheaper than one with low temperature SQUIDs. In this paper, we present our study of such a NDT device using a high temperature superconducting rf-SQUID as a gradiometer sensor. The result clearly demonstrates the expected sensitivity of the system, and indicates the feasibility of building a portable HTS SQUID NDT device with the help from cryocooler industry. Such a NDT device will have a significant impact on metal corrosion or crack detection technology

  15. Axon-Schwann cell interaction in the squid nerve fibre.

    Science.gov (United States)

    Villegas, J

    1972-09-01

    The electrical properties of Schwann cells and the effects of neuronal impulses on their membrane potential have been studied in the giant nerve fibre of the squid.1. The behaviour of the Schwann cell membrane to current injection into the cell was ohmic. No impulse-like responses were observed with displacements of 35 mV in the membrane potential. The resistance of the Schwann cell membrane was found to be approximately 10(3) Omega cm(2).2. A long-lasting hyperpolarization is observed in the Schwann cells following the conduction of impulse trains by the axon. Whereas the propagation of a single impulse had little effect, prolonged stimulation of the fibre at 250 impulses/sec was followed by a hyperpolarization of the Schwann cell that gradually declined over a period of several minutes.3. The prolonged effects of nerve impulse trains on the Schwann cell were similar to those produced by depolarizing current pulses applied to the axon by the voltage-clamp technique. Thus, a series of depolarizing pulses in the axon was followed by a long-lasting hyperpolarization of the Schwann cells. In contrast, the application of a series of hyperpolarizing 100 mV pulses at a frequency of 1/sec had no apparent effects.4. Changes in the external potassium concentration did not reproduce the long-lasting effects of nerve excitation.5. The hyperpolarizing effects of impulse trains were abolished by the incubation of the nerve fibre in a sea-water solution containing trypsin.6. These findings are discussed in relation to the possible mechanisms that might be responsible for the long-lasting hyperpolarizations of the Schwann cells.

  16. Quantum decay of metastable current states in rf squids

    International Nuclear Information System (INIS)

    Dmitrenko, I.M.; Khlus, V.A.; Tsoj, C.M.; Shnyrkov, V.I.

    1985-01-01

    Quantum decay of metastable current states in a rf SQUID superconducting ring of a hysteresis mode are considered. Point contacts are used as a Josephson weak link. The first derivative of rf IVC, dVsub(T)/dIsub(RF), is measured which gives the dependence of the density of decay probability on the amplitude of magnetic flux oscillations in the ring. The temperature dependence of probability distribution width between 4.2 and 0.5 K suggests that for most of high-ohmic contacts Nb-Nb, Nb-Ag-Nb the quantum mechanisms of decay become dominant beginning with the temperature of about 2 K. The experimental parameters of distribution of decay probability in the quantum limit are compared to those calculated by the theory of macroscopic quantum tunneling in the limit of high and low dissipation. The experimental values of probability density distribution width and characteristic quantum temperature are higher than the theoretical ones, the fact can be attributed to the deviation of current-phase relation of contact from a sinusoidal one. Besides, some contacts seem to correspond to the case of an intermediate value of dissipation. As the frequency of rf oscillations varies from 30 to 6 MHz, the distribution width remains unchanged in accordance with the theory of quantum tunneling decay of metastable current state in the ring in the limit of high damping. At low temperatures (T approximately 0.5 K), and rather small damping coefficient, the density of probability displays anomalous peaks when the amplitude of rf oscillations is lower considerably than the critical vaiue of magnetic flux in the ring

  17. Rapid prototyping and evaluation of programmable SIMD SDR processors in LISA

    Science.gov (United States)

    Chen, Ting; Liu, Hengzhu; Zhang, Botao; Liu, Dongpei

    2013-03-01

    With the development of international wireless communication standards, there is an increase in computational requirement for baseband signal processors. Time-to-market pressure makes it impossible to completely redesign new processors for the evolving standards. Due to its high flexibility and low power, software defined radio (SDR) digital signal processors have been proposed as promising technology to replace traditional ASIC and FPGA fashions. In addition, there are large numbers of parallel data processed in computation-intensive functions, which fosters the development of single instruction multiple data (SIMD) architecture in SDR platform. So a new way must be found to prototype the SDR processors efficiently. In this paper we present a bit-and-cycle accurate model of programmable SIMD SDR processors in a machine description language LISA. LISA is a language for instruction set architecture which can gain rapid model at architectural level. In order to evaluate the availability of our proposed processor, three common baseband functions, FFT, FIR digital filter and matrix multiplication have been mapped on the SDR platform. Analytical results showed that the SDR processor achieved the maximum of 47.1% performance boost relative to the opponent processor.

  18. Compact laser interferometer for translation and tilt measurement as optical readout for the LISA inertial sensor

    Science.gov (United States)

    Schuldt, Thilo; Gohlke, Martin; Weise, Dennis; Johann, Ulrich; Peters, Achim; Braxmaier, Claus

    2007-10-01

    The space mission LISA (Laser Interferometer Space Antenna) aims at detecting gravitational waves in the frequency range 30 μ Hz to 1Hz. Free flying proof masses inside the satellites act as inertial sensors and represent the end mirrors of the interferometer. In the current baseline design, LISA utilizes an optical readout of the position and tilt of the proof mass with respect to the satellite housing. This readout must have ~ 5pm/√Hz sensitivity for the translation measurement (for frequencies above 2.8mHz with an ƒ -2 relaxation down to 30 μHz) and ~ 10 nrad/√Hz sensitivity for the tilt measurement (for frequencies above 0.1mHz with an ƒ -1 relaxation down to 30 μHz). The University of Applied Sciences Konstanz (HTWG) - in collaboration with Astrium GmbH, Friedrichshafen, and the Humboldt-University Berlin - therefore develops a highly symmetric heterodyne interferometer implementing differential wavefront sensing for the tilt measurement. We realized a mechanically highly stable and compact setup. In a second, improved setup we measured initial noise levels below 5 pm/√Hz and 10 nrad/√Hz, respectively, for frequencies above 10mHz.

  19. Principles, operations, and expected performance of the LISA Pathfinder charge management system

    Energy Technology Data Exchange (ETDEWEB)

    Ziegler, T [Astrium GmbH, 88039 Friedrichshafen (Germany); Fichter, W [iFR, Universitaet Stuttgart, Pfaffenwaldring 7a, 70569 Stuttgart (Germany); Schulte, M [Blackett Laboratory, Imperial College, Prince Consort Road, London SW7 2BZ (United Kingdom); Vitale, S, E-mail: tobias.ziegler@astrium.eads.ne [Department of Physics, University of Trento, 38050 Povo, Trento (Italy)

    2009-03-01

    The test masses of LISA Pathfinder are free flying and therefore not grounded to the spacecraft by a wire. Because of galactic cosmic rays, solar energetic particles, and unknown microscopic surface effects during initial test mass release, an unacceptable level of absolute charge might be present on the test masses. A charged test mass can endanger transition to high accuracy control modes which are required for science experiments. Furthermore, charged test masses introduce unwanted disturbance accelerations for example due to Coulomb interactions with surrounding conducting surfaces. The charge management system is designed to discharge the test masses up to a tolerable level of absolute charge such that the mission goal can be achieved. It is therefore an essential part of the experiments to be performed with the LISA Technology Package. The paper describes charge management tasks to be performed on board the spacecraft and summarizes the principles of charge measurement and discharge control. An overview of the experiment operations is given where the interconnection of operational charge management system modes and operational modes of the drag-free, suspension and attitude control system is considered. Simulated performance results are presented.

  20. LISA time-delay interferometry zero-signal solution: Geometrical properties

    International Nuclear Information System (INIS)

    Tinto, Massimo; Larson, Shane L.

    2004-01-01

    Time-delay interferometry (TDI) is the data processing technique needed for generating interferometric combinations of data measured by the multiple Doppler readouts available onboard the three Laser Interferometer Space Antenna (LISA) spacecraft. Within the space of all possible interferometric combinations TDI can generate, we have derived a specific combination that has zero response to the gravitational wave signal, and called it the zero-signal solution (ZSS). This is a two-parameter family of linear combinations of the generators of the TDI space, and its response to a gravitational wave becomes null when these two parameters coincide with the values of the angles of the source location in the sky. Remarkably, the ZSS does not rely on any assumptions about the gravitational waveform, and in fact it works for waveforms of any kind. Our approach is analogous to the data analysis method introduced by Guersel and Tinto in the context of networks of Earth-based, wideband, interferometric gravitational wave detectors observing in coincidence a gravitational wave burst. The ZSS should be regarded as an application of the Guersel and Tinto method to the LISA data

  1. Metal-amplified Density Assays, (MADAs), including a Density-Linked Immunosorbent Assay (DeLISA).

    Science.gov (United States)

    Subramaniam, Anand Bala; Gonidec, Mathieu; Shapiro, Nathan D; Kresse, Kayleigh M; Whitesides, George M

    2015-02-21

    This paper reports the development of Metal-amplified Density Assays, or MADAs - a method of conducting quantitative or multiplexed assays, including immunoassays, by using Magnetic Levitation (MagLev) to measure metal-amplified changes in the density of beads labeled with biomolecules. The binding of target analytes (i.e. proteins, antibodies, antigens) to complementary ligands immobilized on the surface of the beads, followed by a chemical amplification of the binding in a form that results in a change in the density of the beads (achieved by using gold nanoparticle-labeled biomolecules, and electroless deposition of gold or silver), translates analyte binding events into changes in density measureable using MagLev. A minimal model based on diffusion-limited growth of hemispherical nuclei on a surface reproduces the dynamics of the assay. A MADA - when performed with antigens and antibodies - is called a Density-Linked Immunosorbent Assay, or DeLISA. Two immunoassays provided a proof of principle: a competitive quantification of the concentration of neomycin in whole milk, and a multiplexed detection of antibodies against Hepatitis C virus NS3 protein and syphilis T. pallidum p47 protein in serum. MADAs, including DeLISAs, require, besides the requisite biomolecules and amplification reagents, minimal specialized equipment (two permanent magnets, a ruler or a capillary with calibrated length markings) and no electrical power to obtain a quantitative readout of analyte concentration. With further development, the method may be useful in resource-limited or point-of-care settings.

  2. Parasites and hepatic histopathological lesions in lisa (Mugil incilis from Totumo mash, North of Colombia

    Directory of Open Access Journals (Sweden)

    Jesús Olivero V.

    2013-03-01

    Full Text Available Objective. To assess the levels of parasitism by nematodes and trematodes, as well as the hepatic histopathological alterations present in Mugil incilis (Lisa from Totumo marsh, North of Colombia. Materials and methods. Between July 2004 and June 2005, 500 fish were collected at Totumo Marsh (75°16’W and 10°44´N, North of Colombia. Morphometric and parasitic parameters were determined for each specimen, and the hepatic histopathological status of the liver was assessed by analyzing liver slides stained with hematoxylin and eosin. Results. Nematode larvae isolated from Mugil incilis corresponded to Contracaecum spp. Parasite prevalence was 60.49%. Parasitic mean abundance and mean intensity were 4.8±1.05 and 7.02±1.49, nematodes per fish, respectively. The correlation between nematode mean abundance and fish length was significant and positive (r=0.525, p<0.0001, but negative for condition factor (r=-0.109, p=0.014. Hepatic histopathological analysis revealed the presence of encapsulated trematode larvae as the main finding. However, the presence of inflammation, granulomas, steatosis and necrosis, were also registered as secondary alterations. Conclusions. Lisas collected at Totumo Marsh are parasitized with nematodes and trematodes. These fish have different histopathological lesions in the liver tissue, being the most important the presence of trematode encapsulated cyst that generate inflammatory reactions, and negatively correlate with morphometric markers of fish health.

  3. Constraints on LISA Pathfinder's Self-Gravity: Design Requirements, Estimates and Testing Procedures

    Science.gov (United States)

    Armano, M.; Audley, H.; Auger, G.; Baird, J.; Binetruy, P.; Born, M.; Bortoluzzi, M.; Brandt, Nico; Bursi, Alessandro; Slutsky. J.; hide

    2016-01-01

    LISA Pathfinder satellite was launched on 3 December 2015 toward the Sun Earth first Lagrangian point (L1) where the LISA Technology Package (LTP), which is the main science payload, will be tested. LTP achieves measurements of differential acceleration of free-falling test masses (TMs) with sensitivity below 3 x 10(exp -14) m s(exp -2) Hz(exp - 1/2) within the 130 mHz frequency band in one dimension. The spacecraft itself is responsible for the dominant differential gravitational field acting on the two TMs. Such a force interaction could contribute a significant amount of noise and thus threaten the achievement of the targeted free-fall level. We prevented this by balancing the gravitational forces to the sub nm s(exp -2) level, guided by a protocol based on measurements of the position and the mass of all parts that constitute the satellite, via finite element calculation tool estimates. In this paper, we will introduce the gravitational balance requirements and design, and then discuss our predictions for the balance that will be achieved in flight.

  4. Simulation of the charging process of the LISA test masses due to solar flares

    International Nuclear Information System (INIS)

    Vocca, H; Grimani, C; Amico, P; Bosi, L; Marchesoni, F; Punturo, M; Travasso, F; Barone, M; Stanga, R; Vetrano, F; Vicere, A

    2004-01-01

    Cosmic-ray and solar high energy particles penetrate the LISA experiment test masses. Consequently, an electric charge accumulates in the bodies of the masses, generating spurious Coulomb forces between the masses and the surrounding electrodes. This process increases the noise level of the experiment. We have estimated the amount of charge deposited per second on the LISA test masses by solar flares and primary cosmic-ray protons at solar minimum. The simulation has been carried out with the Fluka Monte Carlo program. A simplified geometry for the experiment has been considered. We have found a net charging rate of 37 ± 1 e + /s for primary protons at solar minimum between 0.1 and 1000 GeV/n. The amount of charge released by a medium-strong solar flare, like that of 16 February 1984, is 10 732 ± 30 e + /s in the energy range 0.1-10 GeV/n. This value increases or decreases by approximately one order of magnitude for strong (weak) solar flares

  5. Filter arrays

    Science.gov (United States)

    Page, Ralph H.; Doty, Patrick F.

    2017-08-01

    The various technologies presented herein relate to a tiled filter array that can be used in connection with performance of spatial sampling of optical signals. The filter array comprises filter tiles, wherein a first plurality of filter tiles are formed from a first material, the first material being configured such that only photons having wavelengths in a first wavelength band pass therethrough. A second plurality of filter tiles is formed from a second material, the second material being configured such that only photons having wavelengths in a second wavelength band pass therethrough. The first plurality of filter tiles and the second plurality of filter tiles can be interspersed to form the filter array comprising an alternating arrangement of first filter tiles and second filter tiles.

  6. Science with the space-based interferometer eLISA. II. Gravitational waves from cosmological phase transitions

    International Nuclear Information System (INIS)

    Caprini, Chiara; Hindmarsh, Mark; Helsinki Univ.; Huber, Stephan

    2016-04-01

    We investigate the potential for the eLISA space-based interferometer to detect the stochastic gravitational wave background produced by strong first-order cosmological phase transitions. We discuss the resulting contributions from bubble collisions, magnetohydrodynamic turbulence, and sound waves to the stochastic background, and estimate the total corresponding signal predicted in gravitational waves. The projected sensitivity of eLISA to cosmological phase transitions is computed in a model-independent way for various detector designs and configurations. By applying these results to several specific models, we demonstrate that eLISA is able to probe many well-motivated scenarios beyond the Standard Model of particle physics predicting strong first-order cosmological phase transitions in the early Universe.

  7. Detection of thermal aging degradation and plastic strain damage for duplex stainless steel using SQUID sensor

    International Nuclear Information System (INIS)

    Otaka, M.; Evanson, S.; Hesegawa, K.; Takaku, K.

    1991-01-01

    An apparatus using a SQUID sensor is developed for nondestructive inspection. The measurements are obtained with the SQUID sensor located approximately 150 mm from the specimen. The degradation of thermal aging and plastic strain for duplex stainless steel is successfully detected independently from the magnetic characterization measurements. The magnetic flux density under high polarizing field is found to be independent of thermal aging. Coercive force increases with thermal aging time. On the other hand, the magnetic flux density under high field increases with the plastic strain. Coercive force is found to be independent of the plastic strain. (author)

  8. Verification of the weak equivalence principle of supports and heavy masses using SQUIDs; Ueberpruefung des schwachen Aequivalenzprinzips von Traegern und schwerer Masse mittels Squids

    Energy Technology Data Exchange (ETDEWEB)

    Vodel, W.; Nietzsche, S.; Neubert, R. [Friedrich-Schiller-Universitaet Jena (Germany). Inst. fuer Festkoerperphysik; Dittus, H. [Univ. Bremen (Germany). Zentrum fuer angewandte Raumfahrttechnologie und Mikrogravitation

    2003-07-01

    The weak equivalence principle is one of the fundamental hypotheses of general relativity and one of the key elements of our physical picture of the world, but since Galileo there has been no satisfactory way of verifying it. The new SQUID technology may offer a solution. The contribution presents the experiments of Jena University. Applications are envisaged, e.g., in the STEP space mission of the NASA/ESA. [German] Das Schwache Aequivalenzprinzip ist eine der grundlegenden Hypothesen der Allgemeinen Relativitaetstheorie und damit einer der Grundpfeiler unseres physikalischen Weltbildes. Obwohl es seit den ersten Experimenten von Galileo Galilei am Schiefen Turm zu Pisa im Jahre 1638 bis heute schon zahlreiche und immer praeziser werdende Messungen zur Ueberpruefung der Aequivalenz von schwerer und traeger Masse gegeben hat, ist die strenge Gueltigkeit dieses fundamentalen Prinzips experimentell vergleichsweise unzureichend bestimmt. Neuere Methoden, wie der Einsatz SQUID-basierter Messtechnik und die Durchfuehrung von Experimenten auf Satelliten, lassen Verbesserungen schon in naher Zukunft erwarten, so dass theoretische Ueberlegungen zur Vereinigung aller uns bekannten physikalischen Wechselwirkungen, die eine Verletzung des Schwachen Aequivalenzprinzips voraussagen, experimentell eingegrenzt werden koennten. Der Beitrag gibt einen Ueberblick ueber die an der Universitaet Jena entwickelte SQUID-basierte Messtechnik zum Test des Aequivalenzprinzips und fasst die bisher bei Freifallversuchen am Fallturm Bremen erzielten experimentellen Ergebnisse zusammen. Ein Ausblick auf die geplante Raumfahrtmission STEP der NASA/ESA zum Praezisionstest des Schwachen Aequivalenzprinzips schliesst den Beitrag ab. (orig.)

  9. EDITORIAL: Proceedings of the 7th International LISA Symposium, Barcelona, Spain, 16-20 June 2008 Proceedings of the 7th International LISA Symposium, Barcelona, Spain, 16-20 June 2008

    Science.gov (United States)

    Lobo, Alberto; Sopuerta, Carlos F.

    2009-05-01

    In June 2006 the LISA International Science Team (LIST) accepted the bid presented by the Institut d'Estudis Espacials de Catalunya (IEEC) to host the 7th International LISA Symposium. This was during its 11th meeting at the University of Maryland, just before the 6th edition of the symposium started at NASA's Goddard Space Flight Center. The 7th International LISA Symposium took place in the city of Barcelona, Spain, 16-20 June, 2008, in the premises of CosmoCaixa, a modern science museum located in the hills near Tibidabo. Almost 240 delegates registered for the event, a record breaking figure compared to previous editions of the symposium. Many of the most renowned world experts in LISA, gravitational wave science, and astronomy, as well as engineers, attended LISA #7 and produced state of the art presentations, while everybody benefited from the opportunity to have live discussions during the week in a friendly environment. The programme included 31 invited plenary lectures in the mornings, and eight parallel sessions in the afternoons. These were classified into seven major areas of research: LISA Technology, LISA PathFinder, LISA PathFinder Data Analysis, LISA Data Analysis, Gravitational Wave Sources, Cosmology and Fundamental Physics with LISA and Other Gravitational Wave Detectors. Abstracts for 138 communications were received, from which a selection was made by the session convenors which would fit time constraints. Up to 63 posters completed the scientific programme. More details on the programme, including some of the talks, can be found at the symposium website:http://www.ice.cat/research/LISA_Symposium. There was, however, a remarkable add-on: Professor Clifford Will delivered a startling presentation to the general public, who completely filled the Auditori—the main conference room, 320 seats—and were invited to ask questions to the speaker who boldly guided them through the daunting world of Black Holes, Waves of Gravity, and other Warped Ideas

  10. Cadmium content in fresh and canned squid (Loligo opalescens) from the Pacific coastal waters of California (USA).

    Science.gov (United States)

    Galitsopoulou, A; Georgantelis, D; Kontominas, M G

    2009-01-01

    Cadmium (Cd) levels were determined in 70 samples of mantle tissue and 70 whole individual squid (Loligo opalescens; commercially known as California squid). Samples were collected from the coastal zones of California (USA) during the period 2007/2008. To further investigate consumer exposure to processed fishery products, cadmium concentration was also determined in 200 canned samples of squid. Cd concentrations in raw mantle were low, between 0.01 and 0.29 mg kg(-1) and below the tolerance limit of current regulations (1 mg kg(-1)). Respective concentrations in whole individuals were significantly higher, ranging from 0.51 to 1.18 mg kg(-1), attributed to the presence of the visceral portion in whole squid samples. Cd concentrations varied in relation to age and sex of squid, indicating that several physiological factors may influence accumulation. Furthermore, canning of squid substantially enhanced Cd levels. Cd concentration ranged 0.17-0.67 mg kg(-1) in canned mantle tissue and 0.86-2.07 mg kg(-1) in canned whole squid samples, due to both concentration after canning and movement of the metal between different tissues. Several biological compounds, including metallothioneins, nucleic acids and enzymes, may affect Cd concentrations in commercial fishery products.

  11. Effects of Gamma Irradiation on Shelf-Life and Sensory Scores of Squid Sundae under Accelerated Storage Conditions

    International Nuclear Information System (INIS)

    Kim, H.J.; Kim, K.B.W.R.; Kim, D.H.; Sunwoo, C.; Jung, S.A.; Jeong, D.H.; Jung, H.Y.; Ahn, D.H.; Kim, J.H.; Lee, J.W.; Do, S.R.; Byun, M.W.

    2012-01-01

    This study was conducted to examine the effects of gamma irradiation on the shelf-life and sensory scores of squid Sundae under accelerated storage conditions. Squid Sundae was stored at 37°C for 35 days following gamma irradiation at doses of 0, 10, and 20 kGy. For total viable cell counts, control and gamma-irradiated (GI) (10 kGy) squid Sundae were already spoiled in 4 days, whereas GI (20 kGy) squid Sundae showed complete suppression of bacterial growth during storage. There were no significant changes in pH values compared to the control. The VBN and TBARS (thiobarbituric acid reactive substance) values of GI (20 kGy) squid Sundae were significantly lower than those of the control. In addition, the induction period of GI (20 kGy) squid Sundae as measured by a Rancimat showed a higher level compared to that of the control. In the sensory evaluation, there were no significant changes between the control and GI samples. These results suggest that a dose of 20 kGy is the optimum and effective dose for preservation of squid Sundae. (author)

  12. Potential use of stable isotope and fatty acid analyses for traceability of geographic origins of jumbo squid (Dosidicus gigas).

    Science.gov (United States)

    Gong, Yi; Li, Yunkai; Chen, Xinjun; Chen, Ling

    2018-04-15

    Squid is an important seafood resource for Asian and European countries. With the continuous development of processed squid products, an effective traceability system has become increasingly prominent. Here, we attempt to trace the fishery products of the main target species, jumbo squid (Dosidicus gigas), by using biochemical tracers. Carbon and nitrogen isotope ratios (δ 13 C and δ 15 N values) and fatty acid profiles were identified in squid from three harvest locations in the eastern Pacific Ocean by isotope ratio mass spectrometry and gas chromatography/mass spectrometry, respectively. Comparative analysis was used to evaluate the geographic variations in tracers and to identify the suitable discriminatory variables among origins. Significant spatial variations were found in isotopic values and fatty acid profiles in squid muscle tissues, possibly because of different food availability and/or oceanographic conditions that each group experiences at a given location. The stepwise discriminant analysis indicated that δ 15 N, C16:1n7, C17:1n7, C18:2n6, C20:1 and C20:4n6 were effective variables at differentiating origin. Combined use of stable isotope ratios and fatty acid analyses could trace geographic origins of jumbo squid. This study provides an alternative approach for improving authenticity evaluation of commercial squid products. Copyright © 2018 John Wiley & Sons, Ltd.

  13. Expression of squid iridescence depends on environmental luminance and peripheral ganglion control.

    Science.gov (United States)

    Gonzalez-Bellido, P T; Wardill, T J; Buresch, K C; Ulmer, K M; Hanlon, R T

    2014-03-15

    Squid display impressive changes in body coloration that are afforded by two types of dynamic skin elements: structural iridophores (which produce iridescence) and pigmented chromatophores. Both color elements are neurally controlled, but nothing is known about the iridescence circuit, or the environmental cues, that elicit iridescence expression. To tackle this knowledge gap, we performed denervation, electrical stimulation and behavioral experiments using the long-fin squid, Doryteuthis pealeii. We show that while the pigmentary and iridescence circuits originate in the brain, they are wired differently in the periphery: (1) the iridescence signals are routed through a peripheral center called the stellate ganglion and (2) the iridescence motor neurons likely originate within this ganglion (as revealed by nerve fluorescence dye fills). Cutting the inputs to the stellate ganglion that descend from the brain shifts highly reflective iridophores into a transparent state. Taken together, these findings suggest that although brain commands are necessary for expression of iridescence, integration with peripheral information in the stellate ganglion could modulate the final output. We also demonstrate that squid change their iridescence brightness in response to environmental luminance; such changes are robust but slow (minutes to hours). The squid's ability to alter its iridescence levels may improve camouflage under different lighting intensities.

  14. Effect of electron beam on the microbiological and sensory characteristics of squid jeotkal and its ingredients

    International Nuclear Information System (INIS)

    Liu Xiande; Piao Linghua

    2012-01-01

    A seasoned squid Jeotkal, Koran traditional fermented seafood, and its ingredients for manufacturing, including red hot pepper powder and ground garlic were irradiated by 0, 0.5, 1, 2 and 5 kGy electron beam and stored at 4 ℃ for 4 weeks to determine the changes of microorganisms and sensory characteristics. The initial contamination of squid Jeotkal such as total aerobic bacteria, yeast and mold, and coliform bacterial were at the levels of 2.88, 3.04 and 4.20 logCFU/g, respectively. However, 5 kGy electron beam irradiation reduced the total aerobic bacteria about 1 logCFU/g. Yeast and mold and coliform bacterial were reduced 1 ∼ 2 logCFU/g after 2 kGy irradiation and reached to undetected level when the sample was irradiated at 5 kGy and following storage at 4 ℃ for 4 weeks. Sensory characteristics showed that 5 kGy electron beam irradiation did not adversely affect overall acceptability of squid Jeotkal and its ingredients during 4 ℃ storage. Therefore, electron beam irradiation is one of the possible methods to improve storage stability of seasoned squid Jeotkal. (authors)

  15. Highly balanced gradiometer systems based on HTS-SQUIDs for the use in magnetically unshielded environment

    NARCIS (Netherlands)

    Borgmann, H.J.R.; Rijpma, A.P.; ter Brake, Hermanus J.M.; Rogalla, Horst; David, P.

    1999-01-01

    Two different concepts for gradiometer formation were tested applying high-temperature rf SQUIDs operated at 77 K in liquid nitrogen. All gradiometer systems are fully based on magnetometers. The first concept applies a compensating magnetometer at different positions to actively cancel the magnetic

  16. Integrated de SQUID magnetometer with high dV/dB

    International Nuclear Information System (INIS)

    Drung, D.; Cantor, R.; Peters, M.; Ryhanen, T.; Kochi, H.

    1991-01-01

    This paper presents a directly coupled dc SQUID magnetometer with very simple feedback electronics. The magnetometer has been integrated on a 7.2 x 7.2 mm 2 chip and fabricated using a four-level Nb/Si x N v /Nb process. Eight pick-up loops are connected in parallel to directly form the SQUID inductance of about 0.4 nH which leads to a high sensitivity B/Φ = 0.47 nT/Φ. An Additional Positive Feedback (APF) circuit on the magnetometer chip has been used to increase the gradient of the V-μ characteristic to dV/dΦ ≅ 300 μV/Φ 0 at the SQUID operating point. The resulting gradient of the transfer function of dV/dB ≅ 640 μV/nT makes it possible to directly read out the SQUID without helium temperature impedance matching circuits or flux modulation techniques

  17. Magnetic properties of thin Ni films measured by a dc SQUID-based magnetic microscope

    DEFF Research Database (Denmark)

    Snigirev, O.V.; Andreev, K.E.; Tishin, A.M.

    1997-01-01

    We have applied a scanning HTS (high-temperature superconductor) de SQUID (superconducting quantum interference device) -based magnetic microscope to study the magnetic properties of Au/Ni/Si(100) films in the thickness range from 8 to 200 Angstrom at T = 77 K. A one-domain structure with in...

  18. The effects of jig color and lunar bright on coastal squid jigging ...

    African Journals Online (AJOL)

    Squid jigging experiments were carried out to determine whether differences occurred between different colors and lunar brightness in Middle Eastern coast of Aegean Sea. Five different colors of jigs (red, blue, green, orange and white) were used together in same angle. According to one-way analysis of variance results, ...

  19. Rotational population patterns and searches for the nuclear SQUID (Superconducting Quantum Interference Device)

    International Nuclear Information System (INIS)

    Canto, L.F.; Donangelo, R.J.; Farhan, A.R.; Guidry, M.W.; Rasmussen, J.O.; Ring, P.; Stoyer, M.A.

    1989-11-01

    This paper presents new theoretical results for rotational population patterns in the nuclear SQUID effect. (The term nuclear SQUID is in analogy to the solid-state Superconducting Quantum Interference Devices.) The SQUID effect is an interesting new twist to an old quest to understand Coriolis anti-pairing (CAP) effects in nuclear rotational bands. Two-neutron transfer reaction cross sections among high-spin states have long been touted as more specific CAP probes than other nuclear properties. Heavy projectiles like Sn or Pb generally are recommended to pump the deformed nucleus to as high spin as possible for transfer. The interference and sign reversal of 2n transfer amplitudes at high spin, as predicted in the early SQUID work imposes the difficult requirement of Coulomb pumping to near back-bending spins at closest approach. For Pb on rare earths we find a dramatic departure from sudden-approximation, so that the population depression occurs as low as final spin 10h. 14 refs., 8 figs

  20. High-Tc SQUID Application for Roll to Roll Metallic Contaminant Detector

    International Nuclear Information System (INIS)

    Tanaka, S.; Kitamura, Y.; Uchida, Y.; Hatsukade, Y.; Ohtani, T.; Suzuki, S.

    2012-01-01

    A sensitive eight-channel high-Tc Superconducting Interference Device (SQUID) detection system for magnetic contaminant in a lithium ion battery anode was developed. Finding ultra-small metallic foreign matter is an important issue for a manufacturer because metallic contaminants carry the risk of an internal short. When contamination occurs, the manufacturer of the product suffers a great loss from recalling the tainted product. Metallic particles with outer dimensions smaller than 100 microns cannot be detected using a conventional X-ray imaging system. Therefore, a highly sensitive detection system for small foreign matter is required. We have already developed a detection system based on a single-channel SQUID gradiometer and horizontal magnetization. For practical use, the detection width of the system should be increased to at least 65 mm by employing multiple sensors. In this paper, we present an 8-ch high-Tc SQUID roll-to-roll system for inspecting a lithium-ion battery anode with a width of 65 mm. A special microscopic type of a cryostat was developed upon which eight SQUID gradiometers were mounted. As a result, small iron particles of 35 microns on a real lithium-ion battery anode with a width of 70 mm were successfully detected. This system is practical for the detection of contaminants in a lithium ion battery anode sheet.

  1. Comparison live adult Artemia and squid meat on the growth of Penaeid shrimp Metapenaeus dobsoni (Miers)

    Digital Repository Service at National Institute of Oceanography (India)

    Nair, S.R.S.; Achuthankutty, C.T.; Royan, J.P.

    An experiment lasting 14 weeks was conducted to compare the efficiency of live adult Artemia with fresh squid meat on growth of penaeid shrimp Metapenaeus dobsoni. The shrimps were found actively feeding on live Artemia and grew 84% more than those...

  2. A simple method for checking the balance of gradiometers used with squids

    International Nuclear Information System (INIS)

    Eghrari, I.R.; Ribeiro, P.C.

    1978-11-01

    A simple technique for detecting the degree of balance of first order gradiometers before connecting them to the SQUID is described. The effect of thermal cycling on this balance is given for different materials used in the construction of the gradiometers [pt

  3. Ocean acidification responses in paralarval squid swimming behavior using a novel 3D tracking system

    KAUST Repository

    Zakroff, Casey J.; Mooney, T. Aran; Wirth, Colin

    2017-01-01

    . pealeii from eggs reared under chronic OA demonstrated measurable impairments to swimming activity and control. This required the development of a novel, cost-effective, and robust method for 3D motion tracking and analysis. Squid eggs were reared in pCO2

  4. Rapid Associative Learning and Stable Long-Term Memory in the Squid Euprymna scolopes.

    Science.gov (United States)

    Zepeda, Emily A; Veline, Robert J; Crook, Robyn J

    2017-06-01

    Learning and memory in cephalopod molluscs have received intensive study because of cephalopods' complex behavioral repertoire and relatively accessible nervous systems. While most of this research has been conducted using octopus and cuttlefish species, there has been relatively little work on squid. Euprymna scolopes Berry, 1913, a sepiolid squid, is a promising model for further exploration of cephalopod cognition. These small squid have been studied in detail for their symbiotic relationship with bioluminescent bacteria, and their short generation time and successful captive breeding through multiple generations make them appealing models for neurobiological research. However, little is known about their behavior or cognitive ability. Using the well-established "prawn-in-the-tube" assay of learning and memory, we show that within a single 10-min trial E. scolopes learns to inhibit its predatory behavior, and after three trials it can retain this memory for at least 12 d. Rapid learning and very long-term retention were apparent under two different training schedules. To our knowledge, this study is the first demonstration of learning and memory in this species as well as the first demonstration of associative learning in any squid.

  5. A nitrogen triple-point thermal storage unit for cooling a SQUID magnetometer

    NARCIS (Netherlands)

    Rijpma, A.P.; Meenderink, D.J.; Reincke, H.A.; Venhorst, G.C.F.; Holland, H.J.; Brake, ter H.J.M.

    2005-01-01

    In order to achieve turnkey operation, the use is planned of cryocoolers to cool a SQUID magnetometer system. To minimize the magnetical and mech. interference from the coolers, they are switched off during the actual measurements. Consequently, a thermal storage unit (TSU) is required with

  6. A nitrogen triple-point thermal storage unit for cooling a SQUID magnetometer

    NARCIS (Netherlands)

    Rijpma, A.P.; Meenderink, D.J.; Reincke, H.A.; Venhorst, G.C.F.; Venhorst, G.C.F.; Holland, Herman J.; ter Brake, Hermanus J.M.

    2005-01-01

    In order to achieve turnkey operation, we plan to use cryocoolers to cool a SQUID magnetometer system. To minimize the magnetical and mechanical interference from the coolers, we intend to switch them off during the actual measurements. Consequently, a thermal storage unit (TSU) is required with

  7. Closed-cycle gas flow system for cooling a HTc dc-SQUID magnetometer

    NARCIS (Netherlands)

    Bosch, van den P.J.; Holland, H.J.; Brake, ter H.J.M.; Rogalla, H.

    1994-01-01

    A closed-cycle gas flow system for cooling a high-crit. temp. d.c.-superconducting quantum interference device (SQUID) magnetometer by means of a cryocooler has been designed, constructed and tested. The magnetometer is aimed to measure heart signals with a sensitivity of 0.1 pT/Hz1/2. The required

  8. Analysis of metal catalyst content in magnetically filtered SWCNTs by SQUID magnetometry

    Czech Academy of Sciences Publication Activity Database

    Pacáková, Barbara; Komínková, Zuzana; Vejpravová, Jana; Kalbáč, Martin

    2015-01-01

    Roč. 50, č. 6 (2015), s. 2544-2553 ISSN 0022-2461 R&D Projects: GA ČR GAP204/10/1677 Institutional support: RVO:68378271 ; RVO:61388955 Keywords : single-wall carbon nanotubes * nanoparticles * magnetic filtration * SQUID Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.302, year: 2015

  9. Characterization of single-core magnetite nanoparticles for magnetic imaging by SQUID relaxometry

    International Nuclear Information System (INIS)

    Adolphi, Natalie L; Huber, Dale L; Monson, Todd C; Provencio, Paula P; Bryant, Howard C; Fegan, Danielle L; Tessier, Trace E; Flynn, Edward R; Lim, JitKang; Majetich, Sara A; Trujillo, Jason E; Lovato, Debbie M; Butler, Kimberly S; Larson, Richard S; Hathaway, Helen J

    2010-01-01

    Optimizing the sensitivity of SQUID (superconducting quantum interference device) relaxometry for detecting cell-targeted magnetic nanoparticles for in vivo diagnostics requires nanoparticles with a narrow particle size distribution to ensure that the Neel relaxation times fall within the measurement timescale (50 ms-2 s, in this work). To determine the optimum particle size, single-core magnetite nanoparticles (with nominal average diameters 20, 25, 30 and 35 nm) were characterized by SQUID relaxometry, transmission electron microscopy, SQUID susceptometry, dynamic light scattering and zeta potential analysis. The SQUID relaxometry signal (detected magnetic moment/kg) from both the 25 nm and 30 nm particles was an improvement over previously studied multi-core particles. However, the detected moments were an order of magnitude lower than predicted based on a simple model that takes into account the measured size distributions (but neglects dipolar interactions and polydispersity of the anisotropy energy density), indicating that improved control of several different nanoparticle properties (size, shape and coating thickness) will be required to achieve the highest detection sensitivity. Antibody conjugation and cell incubation experiments show that single-core particles enable a higher detected moment per cell, but also demonstrate the need for improved surface treatments to mitigate aggregation and improve specificity.

  10. Characterization of single-core magnetite nanoparticles for magnetic imaging by SQUID relaxometry

    Energy Technology Data Exchange (ETDEWEB)

    Adolphi, Natalie L [Department of Biochemistry and Molecular Biology, University of New Mexico, Albuquerque, NM 87131 (United States); Huber, Dale L; Monson, Todd C; Provencio, Paula P [Sandia National Laboratories, P. O. Box 5800, Albuquerque, NM 87185 (United States); Bryant, Howard C; Fegan, Danielle L; Tessier, Trace E; Flynn, Edward R [Senior Scientific, LLC, 11109 Country Club NE, Albuquerque, NM 87111 (United States); Lim, JitKang; Majetich, Sara A [Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213 (United States); Trujillo, Jason E; Lovato, Debbie M; Butler, Kimberly S; Larson, Richard S [Department of Pathology, Cancer Research and Treatment Center, University of New Mexico, Albuquerque, NM 87131 (United States); Hathaway, Helen J, E-mail: NAdolphi@salud.unm.ed [Department of Cell Biology and Physiology, University of New Mexico, Albuquerque, NM 87131 (United States)

    2010-10-07

    Optimizing the sensitivity of SQUID (superconducting quantum interference device) relaxometry for detecting cell-targeted magnetic nanoparticles for in vivo diagnostics requires nanoparticles with a narrow particle size distribution to ensure that the Neel relaxation times fall within the measurement timescale (50 ms-2 s, in this work). To determine the optimum particle size, single-core magnetite nanoparticles (with nominal average diameters 20, 25, 30 and 35 nm) were characterized by SQUID relaxometry, transmission electron microscopy, SQUID susceptometry, dynamic light scattering and zeta potential analysis. The SQUID relaxometry signal (detected magnetic moment/kg) from both the 25 nm and 30 nm particles was an improvement over previously studied multi-core particles. However, the detected moments were an order of magnitude lower than predicted based on a simple model that takes into account the measured size distributions (but neglects dipolar interactions and polydispersity of the anisotropy energy density), indicating that improved control of several different nanoparticle properties (size, shape and coating thickness) will be required to achieve the highest detection sensitivity. Antibody conjugation and cell incubation experiments show that single-core particles enable a higher detected moment per cell, but also demonstrate the need for improved surface treatments to mitigate aggregation and improve specificity.

  11. Conversion of Squid Pens to Chitosanases and Proteases via Paenibacillus sp. TKU042

    Directory of Open Access Journals (Sweden)

    Chien Thang Doan

    2018-03-01

    Full Text Available Chitosanases and proteases have received much attention due to their wide range of applications. Four kinds of chitinous materials, squid pens, shrimp heads, demineralized shrimp shells and demineralized crab shells, were used as the sole carbon and nitrogen (C/N source to produce chitosanases, proteases and α-glucosidase inhibitors (αGI by four different strains of Paenibacillus. Chitosanase productivity was highest in the culture supernatants using squid pens as the sole C/N source. The maximum chitosanase activity of fermented squid pens (0.759 U/mL was compared to that of fermented shrimp heads (0.397 U/mL, demineralized shrimp shells (0.201 U/mL and demineralized crab shells (0.216 U/mL. A squid pen concentration of 0.5% was suitable for chitosanase, protease and αGI production via Paenibacillus sp. TKU042. Multi-purification, including ethanol precipitation and column chromatography of Macro-Prep High S as well as Macro-Prep DEAE (diethylaminoethyl, led to the isolation of Paenibacillus sp. TKU042 chitosanase and protease with molecular weights of 70 and 35 kDa, respectively. For comparison, 16 chitinolytic bacteria, including strains of Paenibacillus, were investigated for the production of chitinase, exochitinase, chitosanase, protease and αGI using two kinds of chitinous sources.

  12. Characterization and demonstration results of a SQUID magnetometer system developed for geomagnetic field measurements

    Science.gov (United States)

    Kawai, J.; Miyamoto, M.; Kawabata, M.; Nosé, M.; Haruta, Y.; Uehara, G.

    2017-08-01

    We characterized a low temperature superconducting quantum interference device (SQUID) magnetometer system developed for high-sensitivity geomagnetic field measurement, and demonstrated the detection of weak geomagnetic signals. The SQUID magnetometer system is comprised of three-axis SQUID magnetometers housed in a glass fiber reinforced plastic cryostat, readout electronics with flux locked loop (FLL), a 24-bit data logger with a global positioning system and batteries. The system noise was approximately 0.2 pT √Hz- 1/2 in the 1-50 Hz frequency range. This performance was determined by including the thermal noise and the shielding effect of the copper shield, which covered the SQUID magnetometers to eliminate high-frequency interference. The temperature drift of the system was ˜0.8 pT °C- 1 in an FLL operation. The system operated for a month using 33 l liquid helium. Using this system, we performed the measurements of geomagnetic field in the open-air, far away from the city. The system could detect weak geomagnetic signals such as the Schumann resonance with sixth harmonics, and the ionospheric Alfvén resonance appearing at night, for the north-south and east-west components of the geomagnetic field. We confirm that the system was capable of high-sensitivity measurement of the weak geomagnetic activities.

  13. SQUIDs as detectors in a new experiment to measure the neutron electric dipole moment

    International Nuclear Information System (INIS)

    Espy, M.A.; Cooper, M.; Lamoreaux, S.; Kraus, R.H. Jr.; Matlachov, A.; Ruminer, P.

    1998-01-01

    A new experiment has been proposed at Los Alamos National Laboratory to measure the neutron electric dipole moment (EDM) to 4x10 -28 ecm, a factor of 250 times better than the current experimental limit. Such a measure of the neutron EDM would challenge the theories of supersymmetry and time reversal violation as the origin of the observed cosmological asymmetry in the ratio of baryons to antibaryons. One possible design for this new experiment includes the use of LTC SQUIDs coupled to large (∼100 cm 2 ) pick-up coils to measure the precision frequency of the spin-polarized 3 He atoms that act as polarizer, spin analyzer, detector, and magnetometer for the ultra-cold neutrons used in the experiment. The method of directly measuring the 3 He precession signal eliminates the need for very uniform magnetic fields (a major source of systematic error in these types of experiments). It is estimated that a flux of ∼2x10 -16 Tm 2 (0.1 Φ 0 ) will be coupled into the pick-up coils. To achieve the required signal-to-noise ratio one must have a flux resolution of dΦ SQ = 2x10 -6 Φ 0 /√Hz at 10 Hz. While this is close to the sensitivity available in commercial devices, the effects of coupling to such a large pick-up coil and flux noise from other sources in the experiment still need to be understood. To determine the feasibility of using SQUIDs in such an application the authors designed and built a superconducting test cell, which simulates major features of the proposed EDM experiment, and they developed a two-SQUID readout system that will reduce SQUID noise in the experiment. They present an overview of the EDM experiment with SQUIDs, estimations of required SQUID parameters and experimental considerations. The authors also present the measured performance of a single magnetometer in the test cell as well as the performance of the two SQUID readout technique

  14. Low-frequency noise in high-(Tc) superconductor Josephson junctions, SQUIDs, and magnetometers

    Science.gov (United States)

    Miklich, A. H.

    1994-05-01

    Design and performance of high-T(sub c) dc superconducting quantum interference devices (SQUID's), junctions that comprise them, and magnetometers made from them are described, with attention to sources of 1/f noise. Biepitaxial junctions are found to have large levels of critical current fluctuations which make them unsuitable for low-noise SQUID's; this suggests a poorly connected interface at the grain boundary junction. SQUID's from bicrystal junctions have levels of critical current noise controllable using bias current reversal techniques which leave the noise white down to frequencies of a few Hz. A SQUID with an energy resolution of 1.5 x 10(exp -30) J Hz(exp -1) at 1 Hz is reported. Magnetometers in which a (9 mm)(exp 2) pickup loop is directly coupled to a SQUID body have achieved field resolutions of 93 fT Hz(exp -1/2) down to frequencies below 1 Hz, improving to 39 fT Hz(exp -1/2) at 1 Hz with the addition of a 50mm-diameter single-turn flux transformer. Poor coupling to pickup loop makes it difficult to satisfy competing goals of high field resolution and small detector size necessary for multichannel biomagnetic imaging. Improved coupling is demonstrated by the use of multiturn-input-coil flux transformers, and a resolution of 35 fT Hz(exp -1/2) in the white noise region is reported with a (10 mm)(exp 2) pickup loop. However, additional 1/f noise from processed multilayer structures in the transformer limits the resolution at 1 Hz to 114 fT Hz(exp -1/2). High-T(sub c) SQUID's exhibit additional 1/f noise when cooled in a nonzero static magnetic field because of additional flux vortices trapped in the film, with the noise power at 1 Hz typically increasing by a factor of 10-20 in a field of 0.05mT (0.5 G). Finally, a SQUID-based voltmeter with a resolution of 9.2 pV Hz(exp -1/2) at 10 Hz (24 pV Hz(exp -1/2) at 1 Hz) is described.

  15. Low-Frequency Noise in High-T Superconductor Josephson Junctions, Squids, and Magnetometers.

    Science.gov (United States)

    Miklich, Andrew Hostetler

    The design and performance of high-T_ {rm c} dc superconducting quantum interference devices (SQUIDs), the junctions that comprise them, and magnetometers made from them are described, with special attention paid to sources of 1/f noise. Biepitaxial junctions are found to have large levels of critical current fluctuations which make them unsuitable for low-noise SQUIDs. This noise suggests a poorly connected interface at the grain boundary junction. SQUIDs from bicrystal junctions, in contrast, have levels of critical current noise that are controllable using bias current reversal techniques which leave the noise white down to frequencies of a few Hz. A SQUID with an energy resolution of 1.5times 10^{-30} J Hz^ {-1} at 1 Hz is reported. Magnetometers in which a (9 mm)^2 pickup loop is directly coupled to a SQUID body have achieved field resolutions of 93 fT Hz^{-1/2} down to frequencies below 1 Hz, improving to 39 fT Hz^{-1/2} at 1 Hz with the addition of a 50 mm-diameter single-turn flux transformer. Although the performance of these devices is sufficient for single -channel biomagnetometry or geophysical studies, their relatively poor coupling to the pickup loop makes it difficult to satisfy the competing goals of high field resolution and small detector size necessary for multichannel biomagnetic imaging. Improved coupling is demonstrated by the use of multiturn-input-coil flux transformers, and a resolution of 35 fT Hz^{-1/2} in the white noise region is reported with a (10 mm) ^2 pickup loop. However, additional 1/f noise from the processed multilayer structures in the transformer limits the resolution at 1 Hz to 114 fT Hz^ {-1/2}. High-T_{ rm c} SQUIDs are shown to exhibit additional 1/f noise when they are cooled in a nonzero static magnetic field because of the additional flux vortices trapped in the film, with the noise power at 1 Hz typically increasing by a factor of 10-20 in a field of 0.05 mT (0.5 G). Finally, a SQUID-based voltmeter with a resolution

  16. The low emittance 2.5 GeV synchrotron light source LISA

    International Nuclear Information System (INIS)

    Einfeld, D.; Hormes, J.; Husmann, D.

    1992-01-01

    LISA, a Light source for Industrial and Scientific Applications, has been proposed. Due to the intention to use the source above all for the LIGA (Lithographie, Galvanik, Abformtechnik) method to produce micromechanical structures, the critical wavelength of the synchrotron radiation spectrum is foreseen to be 0.2 nm. Therefore, the electron energy and the field strength of the ring dipoles have been chosen to be 2.5 GeV and 1.5 T, respectively. It is proposed to make use of a modified 'quadrupole ben achromat' (QBA) lattice. The novel feature of this lattice is the application of two types of bending magnets of different lengths, i.e. different bending angels. (author) 9 refs.; 6 figs.; 1 tab

  17. Metaphors Expressing Emotions in Lisa Kleypas’s Rainshadow Road Novel

    Directory of Open Access Journals (Sweden)

    Novi Liana Ko

    2014-05-01

    Full Text Available Metaphors have been always interesting to explore since they are able to represent many things, one of which is feelings. Article examined the metaphorical sentences which expressed emotions found in Lisa Kleypas’s the Rainshadow Road. Library research was conducted to find the kinds of emotions which were expressed by the metaphorical sentences. It was also done to figure out what the metaphors refered to. Another objective was to reveal the most dominant emotion which appeared through the metaphors expressed in the novel. The analysis used metaphor theory to compare the dictionary meaning and the metaphorical one. The result shows that there are various emotions which are expressed through the metaphorical sentences. Happiness is found as the most dominant emotion which appears in the novel.

  18. Actuation stability test of the LISA pathfinder inertial sensor front-end electronics

    Science.gov (United States)

    Mance, Davor; Gan, Li; Weber, Bill; Weber, Franz; Zweifel, Peter

    In order to limit the residual stray forces on the inertial sensor test mass in LISA pathfinder, √ it is required that the fluctuation of the test mass actuation voltage is within 2ppm/ Hz. The actuation voltage stability test on the flight hardware of the inertial sensor front-end electronics (IS FEE) is presented in this paper. This test is completed during the inertial sensor integration at EADS Astrium Friedrichshafen, Germany. The standard measurement method using voltmeter is not sufficient for verification, since the instrument low frequency √ fluctuation is higher than the 2ppm/ Hz requirement. In this test, by using the differential measurement method and the lock-in amplifier, the actuation stability performance is verified and the quality of the IS FEE hardware is confirmed by the test results.

  19. Inference on white dwarf binary systems using the first round Mock LISA Data Challenges data sets

    International Nuclear Information System (INIS)

    Stroeer, Alexander; Veitch, John; Roever, Christian; Bloomer, Ed; Clark, James; Christensen, Nelson; Hendry, Martin; Messenger, Chris; Meyer, Renate; Pitkin, Matthew; Toher, Jennifer; Umstaetter, Richard; Vecchio, Alberto; Woan, Graham

    2007-01-01

    We report on the analysis of selected single source data sets from the first round of the mock LISA data challenges (MLDC) for white dwarf binaries. We implemented an end-to-end pipeline consisting of a grid-based coherent pre-processing unit for signal detection and an automatic Markov Chain Monte Carlo (MCMC) post-processing unit for signal evaluation. We demonstrate that signal detection with our coherent approach is secure and accurate, and is increased in accuracy and supplemented with additional information on the signal parameters by our Markov Chain Monte Carlo approach. We also demonstrate that the Markov Chain Monte Carlo routine is additionally able to determine accurately the noise level in the frequency window of interest

  20. Auxiliary functions of the LISA laser link: ranging, clock noise transfer and data communication

    International Nuclear Information System (INIS)

    Heinzel, Gerhard; Esteban, Juan Jose; Barke, Simon; Otto, Markus; Wang Yan; Garcia, Antonio F; Danzmann, Karsten

    2011-01-01

    The Laser Interferometer Space Antenna (LISA) is required to reduce two important noise sources by post-processing on the ground using time-delay interferometry (TDI): phase noise of the on-board reference clocks and laser frequency noise. To achieve the desired suppression, the TDI algorithm needs measurements of the differential clock noise between any two spacecraft and inter-spacecraft ranging measurements with at least 1 m accuracy, which is beyond the precision of ground-based measurements for deep space missions. Therefore, we need on-board measurements by transmitting clock noise and ranging information between the spacecraft as auxiliary functions of the laser link. This paper reports our current experimental results in clock noise transfer and ranging for noise subtraction via post-processing as well as additional data transfer.

  1. Massive Black Hole Mergers: Can we see what LISA will hear?

    Science.gov (United States)

    Centrella, Joan

    2009-01-01

    Coalescing massive black hole binaries are formed when galaxies merge. The final stages of this coalescence produce strong gravitational wave signals that can be detected by the space-borne LISA. When the black holes merge in the presence of gas and magnetic fields, various types of electromagnetic signals may also be produced. Modeling such electromagnetic counterparts requires evolving the behavior of both gas and fields in the strong-field regions around the black holes. We have taken a first step towards this problem by mapping the flow of pressureless matter in the dynamic, 3-D general relativistic spacetime around the merging black holes. We report on the results of these initial simulations and discuss their likely importance for future hydrodynamical simulations.

  2. eLISA Telescope In-field Pointing and Scattered Light Study

    Science.gov (United States)

    Livas, J.; Sankar, S.; West, G.; Seals, L.; Howard, J.; Fitzsimons, E.

    2017-05-01

    The orbital motion of the three spacecraft that make up the eLISA Observatory constellation causes long-arm line of sight variations of approximately ± one degree over the course of a year. The baseline solution is to package the telescope, the optical bench, and the gravitational reference sensor (GRS) into an optical assembly at each end of the measurement arm, and then to articulate the assembly. An optical phase reference is exchanged between the moving optical benches with a single mode optical fiber (“backlink” fiber). An alternative solution, referred to as in-field pointing, embeds a steering mirror into the optical design, fixing the optical benches and eliminating the backlink fiber, but requiring the additional complication of a two-stage optical design for the telescope. We examine the impact of an in-field pointing design on the scattered light performance.

  3. A constrained Metropolis-Hastings search for EMRIs in the Mock LISA Data Challenge 1B

    International Nuclear Information System (INIS)

    Gair, Jonathan R; Porter, Edward; Babak, Stanislav; Barack, Leor

    2008-01-01

    We describe a search for the extreme-mass-ratio inspiral sources in the Round 1B Mock LISA Data Challenge data sets. The search algorithm is a Monte Carlo search based on the Metropolis-Hastings algorithm, but also incorporates simulated, thermostated and time annealing, plus a harmonic identification stage designed to reduce the chance of the chain locking onto secondary maxima. In this paper, we focus on describing the algorithm that we have been developing. We give the results of the search of the Round 1B data, although parameter recovery has improved since that deadline. Finally, we describe several modifications to the search pipeline that we are currently investigating for incorporation in future searches

  4. Bell's palsy: the answer to the riddle of Leonardo da Vinci's 'Mona Lisa'.

    Science.gov (United States)

    Maloney, W J

    2011-05-01

    The smile of the famed portrait 'The Mona Lisa' has perplexed both art historians and researchers for the past 500 years. There has been a multitude of theories expounded to explain the nature of the model's enigmatic smile. The origin of the model's wry smile can be demonstrated through a careful analysis of both documented facts concerning the portrait--some gathered only recently through the use of modern technology--and a knowledge of the clinical presentation of Bell's palsy. Bell's palsy is more prevalent in women who are either pregnant or who have recently given birth. This paper postulates that the smile of the portrait's model was due to Leonardo da Vinci's anatomically precise representation of a new mother affected by Bell's palsy subsequent to her recent pregnancy.

  5. Tomographic array

    International Nuclear Information System (INIS)

    1976-01-01

    The configuration of a tomographic array in which the object can rotate about its axis is described. The X-ray detector is a cylindrical screen perpendicular to the axis of rotation. The X-ray source has a line-shaped focus coinciding with the axis of rotation. The beam is fan-shaped with one side of this fan lying along the axis of rotation. The detector screen is placed inside an X-ray image multiplier tube

  6. Tomographic array

    International Nuclear Information System (INIS)

    1976-01-01

    A tomographic array with the following characteristics is described. An X-ray screen serving as detector is placed before a photomultiplier tube which itself is placed in front of a television camera connected to a set of image processors. The detector is concave towards the source and is replacable. Different images of the object are obtained simultaneously. Optical fibers and lenses are used for transmission within the system

  7. Selective metallization of polymers using laser induced surface activation (LISA)—characterization and optimization of porous surface topography

    DEFF Research Database (Denmark)

    Zhang, Yang; Hansen, Hans Nørgaard; De Grave, Arnaud

    2011-01-01

    Laser induced selective activation (LISA) is a molded interconnected devices technique for selective metallization of polymers. On the working piece, only the laser-machined area can be metalized in the subsequent plating. The principle of the technology is introduced. Surface analysis was perfor...

  8. Simple Enough--Even for Web Virgins: Lisa Mitten's Access to Native American Web Sites. Web Site Review Essay.

    Science.gov (United States)

    Belgarde, Mary Jiron

    1998-01-01

    A mixed-blood Mohawk urban Indian and university librarian, Lisa Mitten provides access to Web sites with solid information about American Indians. Links are provided to 10 categories--Native nations, Native organizations, Indian education, Native media, powwows and festivals, Indian music, Native arts, Native businesses, and Indian-oriented home…

  9. Search for a stochastic gravitational-wave signal in the second round of the Mock LISA Data Challenges

    International Nuclear Information System (INIS)

    Robinson, E L; Vecchio, A; Romano, J D

    2008-01-01

    The analysis method currently proposed to search for isotropic stochastic radiation with the Laser Interferometer Space Antenna (LISA) relies on the combined use of two LISA channels, one of which is insensitive to gravitational waves, such as the symmetrized Sagnac. For this method to work, it is essential to know how the instrumental noise power in the two channels are related to one another; however, no quantitative estimates of this key information are available to date. The purpose of our study is to assess the performance of the symmetrized Sagnac method for different levels of prior information regarding the instrumental noise. We develop a general approach in the framework of Bayesian inference and an end-to-end analysis algorithm based on Markov chain Monte Carlo methods to compute the posterior probability density functions of the relevant model parameters. We apply this method to data released as part of the second round of the Mock LISA Data Challenges. For the selected (and somewhat idealized) example cases considered here, we find that for a signal whose amplitude dominates the instrumental noise by a factor ∼25, a prior uncertainty of a factor ∼2 in the ratio between the power of the instrumental noise contributions in the two channels allows for the detection of isotropic stochastic radiation. More importantly, we provide a framework for more realistic studies of LISA's performance and development of analysis techniques in the context of searches for stochastic signals

  10. Playing Harry Potter: Essays and interviews on fandom and performance, edited by Lisa S. Brenner [book review

    Directory of Open Access Journals (Sweden)

    Abigail De Kosnik

    2016-09-01

    Full Text Available Review of Lisa S. Brenner, editor. Playing Harry Potter: Essays and interviews on fandom and performance. Jefferson, NC: McFarland, 2015, paperback, $29.95 (238p ISBN 978-0-7864-9657-0, e-book $14.43 (5374 KB ISBN 978-1-4766-2136-4, ASIN B012E9G0R6.

  11. Theory and modelling of the magnetic field measurement in LISA PathFinder

    Energy Technology Data Exchange (ETDEWEB)

    Diaz-Aguilo, M; Garcia-Berro, E [Departament de Fisica Aplicada, Universitat Politecnica de Catalunya, c/Esteve Terrades, 5, 08860 Castelldefels (Spain); Lobo, A, E-mail: marc.diaz.aguilo@fa.upc.ed [Institut d' Estudis Espacials de Catalunya, c/Gran Capita 2-4, Edif. Nexus 104, 08034 Barcelona (Spain)

    2010-02-07

    The magnetic diagnostics subsystem of the LISA Technology Package (LTP) on board the LISA PathFinder (LPF) spacecraft includes a set of four tri-axial fluxgate magnetometers, intended to measure with high precision the magnetic field at their respective positions. However, their readouts do not provide a direct measurement of the magnetic field at the positions of the test masses, and hence an interpolation method must be designed and implemented to obtain the values of the magnetic field at these positions. However, such an interpolation process faces serious difficulties. Indeed, the size of the interpolation region is excessive for a linear interpolation to be reliable while, on the other hand, the number of magnetometer channels do not provide sufficient data to go beyond the linear approximation. We describe an alternative method to address this issue, by means of neural network algorithms. The key point in this approach is the ability of neural networks to learn from suitable training data representing the behaviour of the magnetic field. Despite the relatively large distance between the test masses and the magnetometers, and the insufficient number of data channels, we find that our artificial neural network algorithm is able to reduce the estimation errors of the field and gradient down to levels below 10%, a quite satisfactory result. Learning efficiency can be best improved by making use of data obtained in on-ground measurements prior to mission launch in all relevant satellite locations and in real operation conditions. Reliable information on that appears to be essential for a meaningful assessment of magnetic noise in the LTP.

  12. Theory and modelling of the magnetic field measurement in LISA PathFinder

    International Nuclear Information System (INIS)

    Diaz-Aguilo, M; Garcia-Berro, E; Lobo, A

    2010-01-01

    The magnetic diagnostics subsystem of the LISA Technology Package (LTP) on board the LISA PathFinder (LPF) spacecraft includes a set of four tri-axial fluxgate magnetometers, intended to measure with high precision the magnetic field at their respective positions. However, their readouts do not provide a direct measurement of the magnetic field at the positions of the test masses, and hence an interpolation method must be designed and implemented to obtain the values of the magnetic field at these positions. However, such an interpolation process faces serious difficulties. Indeed, the size of the interpolation region is excessive for a linear interpolation to be reliable while, on the other hand, the number of magnetometer channels do not provide sufficient data to go beyond the linear approximation. We describe an alternative method to address this issue, by means of neural network algorithms. The key point in this approach is the ability of neural networks to learn from suitable training data representing the behaviour of the magnetic field. Despite the relatively large distance between the test masses and the magnetometers, and the insufficient number of data channels, we find that our artificial neural network algorithm is able to reduce the estimation errors of the field and gradient down to levels below 10%, a quite satisfactory result. Learning efficiency can be best improved by making use of data obtained in on-ground measurements prior to mission launch in all relevant satellite locations and in real operation conditions. Reliable information on that appears to be essential for a meaningful assessment of magnetic noise in the LTP.

  13. Elimination of vibrio cholerae in lisa fillets (Mugil cephalus) by gamma radiation

    International Nuclear Information System (INIS)

    Torres, Z.

    1999-03-01

    The elimination of Vibrio cholerae 01 biotype El Tor (1,87 8 cuf/g) in fresh lisa fillets (Mugil cephalus) with radiation doses of 0 and 0,5 kGy was investigated. Furthermore, in order to evaluate physical, chemical and sensory changes, doses of 1,2,3 and 4 kGy were applied to non inoculated fillets of lisa. Finally, D 10 for Vibrio cholerae was determined in a saline suspension (5,2x10 8 cfu/ml) based on the Most Probable Number (MPN) method and radiation doses of 0,5, 0,75, 1,0, 1,25 and 1,5 kGy. D value found in a 1,87 8 cfu/g concentration of fillet was 0,13 kGy. Humidity, protein, fat and ash contents were not affected significantly and remained around 73 to 75,5, 3,8 to 4,2 and 1% respectively. Control samples showed a 'drip' variation ranging between 0,82 and 0,88% and a N-BVT variation between 1,77 and 1,56, 0,89 and 1,99, 2,13 and 2,47, 1,86 and 2,10%, and a N-BVT variation between 17,79 and 30,16, 16,37 and 26,88 16,33 and 25,12, 15,31 and 33,54 mg N/100 g, respectively. The highest life span for the appearance characteristic was obtained by control samples (23 days) and the lowest by samples radiated at 3 and 4 kGy (28 days). 4 kGy dose resulted in organoleptic changes perceived by panelists during tasting of cooked fish. D 10 found in a saline suspension was 0,13 kGy

  14. The biology and ecology of the jumbo squid Dosidicus gigas (Cephalopoda in Chilean waters: a review

    Directory of Open Access Journals (Sweden)

    Christian M Ibáñez

    2015-07-01

    Full Text Available ABSTRACT. The jumbo squid Dosidicus gigas is the most abundant cephalopod species in the southeastern Pacific Ocean, which supports the biggest cephalopod fishery in the world. Due to its growing economic importance, the population growth and distributional expansion of this squid is being increasingly studied. Nevertheless, some basic features of the biology of D. gigas are still unknown or have been poorly investigated. In this review we summarize the known information regarding the biology and ecology of this species in the southeastern Pacific Ocean; we focus on the Chilean region in order to propose hypotheses and research lines for a better understanding the life history of this organism. Available data on the size structure, reproduction and genetics of D. gigas allows us to propose hypotheses related to the squid's life history traits. Based on the current literature and publications of colleagues, we propose two hypotheses regarding the effect of spatial variation on the life history of D. gigas. Hypothesis 1: Squids mature at large sizes and spawn in oceanic waters with warm temperatures where paralarvae and juveniles develop. Immature squids migrate near shore to feed, grow and mature, and then return to the offshore sites to spawn. Hypothesis 2: Alternatively, juvenile D. gigas in the oceanic zone do not migrate to coastal waters and mature at small sizes compared to individuals living near the coast that mature at larger size and migrate to oceanic waters to spawn. We provide background information about the feeding behavior and parasitism of this species, suggesting that D. gigas is an important trophic link in the southeastern Pacific marine ecosystem. However, more studies on the feeding habits, reproduction and parasite load are needed not only to test hypotheses proposed in this study, but also to advance the overall knowledge of this species.

  15. Preparation and characterisation of irradiated crab chitosan and New Zealand Arrow squid pen chitosan

    International Nuclear Information System (INIS)

    Shavandi, Amin; Bekhit, Adnan A.; Bekhit, Alaa El-Din A.; Sun, Zhifa; Ali, M. Azam

    2015-01-01

    The properties of chitosan from Arrow squid (Nototodarus sloanii) pen (CHS) and commercial crab shell (CHC) were investigated using FTIR, DSC, SEM and XRD before and after irradiation at the dose of 28 kGy in the presence or absence of 5% water. Also, the viscosity, deacetylation degree, water and oil holding capacities, colour and antimicrobial activities of the chitosan samples were determined. Irradiation decreased (P < 0.05) the viscosity of CHC from 0.21 to 0.03 Pa s and of CHS from 1.71 to 0.23 Pa s. The inclusion of water had no effect on the viscosity of irradiated chitosan. Irradiation did not affect the degree of deacetylation of CHC, but increased the deacetylation degree of CHS from 72.78 to 82.29% in samples with 5% water. Water and oil holding capacities of CHS (1197.30% and 873.3%, respectively) were higher (P < 0.05) than those found in CHC (340.70% and 264.40%, respectively). The water and oil holding capacities were decreased for both types of chitosan irradiation, but were not affected by the addition of water. Squid pen chitosan was whiter in colour (White Index = 90.06%) compared to CHC (White Index = 83.70%). Generally, the CHC samples (control and irradiated) exhibited better antibacterial activity compared to CHS, but the opposite was observed with antifungal activity. - Highlights: • Chitosan prepared from Arrow squid pens (Nototodarus sloanii). • Chitosan samples were gamma irradiated at 28 kGy. • Squid pen chitosan showed high fat and water uptake capacities compared to crab shell chitosan. • Gamma irradiation enhanced the DDA of squid pen chitosan but not crab shell chitosan.

  16. Fishery biology of jumbo flying squid Dosidicus gigas off Costa Rica Dome

    Science.gov (United States)

    Chen, Xinjun; Li, Jianghua; Liu, Bilin; Li, Gang; Lu, Huajie

    2014-06-01

    The jumbo flying squid ( Dosidicus gigas) population was surveyed with the help of Chinese squid jigging vessels off the Costa Rica Dome (4°-11°N, 90°-100°W) in 2009 and 2010. The daily catch of D. gigas in the two survey cruises ranged from 0 to 5.5 t and was mostly obtained from the areas bounded by 6°-9°N and 91°-94°W and by 6°30'-7°30'N and 96°-97°W. The sea surface temperature in the areas yielding the most catch ranged from 27.5 to 29°C. The sex ratio of the total catch was 3.75:1 (female: male). The mantle length of the squid ranged from 211 to 355 mm (male) and from 204 to 429 mm (female) with an average of 297.9 and 306.7 mm, respectively. In the relationship of the mantle length (mm) and body weight (g) of the squid, there was no significant difference between sexes. The female and male were at a similar maturity, and most individuals are maturing or have matured with a few females being spent. The size (mantle length) and age at the first sexual maturity were 297 mm and 195 d in females, and less than 211 mm and 130 d in males, respectively. Most of the sampled stomachs (70.6%) had no food remains. The major preys of the squids were fish, cephalopods and crustaceans, with the most abundant Myctophum orientale and D. gigas. The preys in more than 65% of the non-empty sampled stomachs evidenced the cannibalism of D. gigas. The results improved current understanding of the fishery biology of D. gigas off the Costa Rica Dome, which may facilitate the assessment and management of relative fishery resources.

  17. Editorial. Special issue of Classical and Quantum Gravity on the proceedings of the 4th international LISA symposium

    International Nuclear Information System (INIS)

    Finn, Lee Samuel

    2003-01-01

    The 4th International LISA Symposium was held at the National Science Foundation Physics Frontier Center for Gravitational Wave Physics at The Pennsylvania State University on 19-24 July 2002. This special issue of Classical and Quantum Gravity is the proceedings of this meeting. LISA - the Laser Interferometer Space Antenna - is part of an international effort to open a new window on the universe. Not all things radiate light, but everything gravitates. Observations of the gravitational waves radiated by black holes and compact binary star systems, in our galaxy and beyond, can reveal details about these systems and their environments that are otherwise inaccessible. The international effort, of which LISA is a part, includes ground-based detectors, and the relationship between LISA and its ground-based detector 'cousins' was an important theme for this Symposium. LISA will observe gravitational waves in the 0.1 mHz to 0.1 Hz band, complementing observations made by ground-based detectors in the 10 Hz to several KHz band. Together they will explore nearly six decades of bandwidth in the gravitational-wave sky. LISA in particular will observe the gravitational waves radiated by the coalescence of black holes at the centres of colliding galaxies, and the inspiral of compact neutron stars or stellar-mass black holes onto these black holes, virtually anywhere in the universe. It will take a census of neutron star or close white dwarf binaries in our own galaxy and observe the formation of large black holes from the very first structures to form and collapse in our universe. In doing all these things, it will shed new 'light' on the first structures to form in the universe, explore the evolution of galaxies and the roles that black holes play in their structure, test relativity near the 'edges' of a black hole, and deepen our understanding of stellar and binary system evolution. A successful conference - and this LISA Symposium, like its predecessors, was very

  18. The mechanics of locomotion in the squid Loligo pealei: locomotory function and unsteady hydrodynamics of the jet and intramantle pressure.

    Science.gov (United States)

    Anderson, E J; DeMont, M E

    2000-09-01

    High-speed, high-resolution digital video recordings of swimming squid (Loligo pealei) were acquired. These recordings were used to determine very accurate swimming kinematics, body deformations and mantle cavity volume. The time-varying squid profile was digitized automatically from the acquired swimming sequences. Mantle cavity volume flow rates were determined under the assumption of axisymmetry and the condition of incompressibility. The data were then used to calculate jet velocity, jet thrust and intramantle pressure, including unsteady effects. Because of the accurate measurements of volume flow rate, the standard use of estimated discharge coefficients was avoided. Equations for jet and whole-cycle propulsive efficiency were developed, including a general equation incorporating unsteady effects. Squid were observed to eject up to 94 % of their intramantle working fluid at relatively high swimming speeds. As a result, the standard use of the so-called large-reservoir approximation in the determination of intramantle pressure by the Bernoulli equation leads to significant errors in calculating intramantle pressure from jet velocity and vice versa. The failure of this approximation in squid locomotion also implies that pressure variation throughout the mantle cannot be ignored. In addition, the unsteady terms of the Bernoulli equation and the momentum equation proved to be significant to the determination of intramantle pressure and jet thrust. Equations of propulsive efficiency derived for squid did not resemble Froude efficiency. Instead, they resembled the equation of rocket motor propulsive efficiency. The Froude equation was found to underestimate the propulsive efficiency of the jet period of the squid locomotory cycle and to overestimate whole-cycle propulsive efficiency when compared with efficiencies calculated from equations derived with the squid locomotory apparatus in mind. The equations for squid propulsive efficiency reveal that the refill

  19. Ferromagnetic resonance response of electron-beam patterned arrays of ferromagnetic nanoparticles

    Science.gov (United States)

    Jung, Sukkoo; Watkins, Byron; Feller, Jeffrey; Ketterson, John; Chandrasekhar, Venkat

    2001-03-01

    We report on the fabrication and the dynamic magnetic properties of periodic permalloy dot arrays. Electron-beam lithography and e-gun evaporation have been used to make the arrays with the aspect ratio of 2 (dot diameter : 40 nm, height : 80 nm) and periods of 100 - 200 nm. The magnetic properties of the arrays and their interactions have been investigated by ferromagnetic resonance (FMR), magnetic force microscopy (MFM), and SQUID magnetometry. The measured FMR data show that the position and magnitude of resonant absorption peaks strongly depend on the angle between magnetic field and the lattice structure. The results of dot arrays with various kinds of structural parameters will be presented. Supported by Army Research Office, DAAD19-99-1-0334/P001

  20. Influence of gamma irradiation and low temperature storage on the quality and shelf life of squid (Doryteuthis sibogae

    Directory of Open Access Journals (Sweden)

    Manjanaik, B.

    2017-08-01

    Full Text Available Irradiation is considered as an efficient method for the reduction of microorganisms in food. It has been used to improve the safety and shelf life of food products. The present investigation is aimed at studying the influence of gamma irradiation (3 and 5 kGy and subsequent storage at refrigeration temperature (4oC on the chemical, microbial qualities and extended shelf life of squid (Doryteuthis sibogae. The total volatile base nitrogen (TVB-N and trimethyl amine nitrogen values (TMA-N of the irradiated squid samples significantly decreased in comparison with the control (non-irradiated stored at 4oC. The thiobarbituric acid values for the irradiated squid was significantly lower than of the non-irradiated samples stored at 4oC (p<0.05. The pH value of the squid was affected significantly by both, irradiation dose and storage temperature (p<0.05. The total microbial load for the non-irradiated squid samples was higher than those of irradiated samples at 4oC temperature. The results revealed that the combination of irradiation and refrigerated storage resulted in a significant reduction of microbial growth and stabilized the biochemical characteristics of squid.