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Sample records for hts squid array

  1. Multiplexed HTS rf SQUID magnetometer array for eddy current testing of aircraft rivet joints

    NASA Astrophysics Data System (ADS)

    Gärtner, S.; Krause, H.-J.; Wolters, N.; Lomparski, D.; Wolf, W.; Schubert, J.; Kreutzbruck, M. v.; Allweins, K.

    2002-05-01

    Using three rf SQUID magnetometers, a multiplexed SQUID array was implemented. The SQUIDs are positioned in line with 7 mm spacing and operated using one feedback electronics with sequential read out demodulation at different radio frequencies (rf). The cross-talk between SQUID channels was determined to be negligible. To show the performance of the SQUID array, eddy current (EC) measurements of aluminum aircraft samples in conjunction with a differential (double-D) EC excitation and lock-in readout were carried out. With computer-controlled continuous switching of the SQUIDs during the scan, three EC signal traces of the sample are obtained simultaneously. We performed measurements with an EC excitation frequency of 135 Hz to localize an artificial crack (sawcut flaw) of 20 mm length in an aluminum sheet with 0.6 mm thickness. The flaw was still detected when covered with aluminum of up to 10 mm thickness. In addition, measurements with varying angles between scanning direction and flaw orientation are presented.

  2. Development of HTS-SQUID Gradiometer with an External HTS Multiturn Thin Film Pickup Coil

    NASA Astrophysics Data System (ADS)

    Teraoka, M.; Tsukamoto, A.; Adachi, S.; Takai, H.; Tanabe, K.

    Highly-sensitive HTS-SQUIDs are applied to various systems such as eddy-current non-destructive evaluation (NDE) and compact magnetometer systems. To avoid unstable operation of the SQUID due to an excitation field, a flux transformer made of normal Cu wire is used to separate the pickup coil and SQUID. However, the resistance of the flux transformer generates thermal noise and reduces the signal bandwidth at low frequencies. In this study, we investigate use of a superconducting flux transformer with resistive connections (SFTR). The SFTR consists of pickup and input coils made of HTS thin films. The two coils are connected by using an HTS coated conductor. The input coil is stacked on an HTS thin film gradiometer. From the measured results of resistances of the connections between each coil and the coated conductor, it was found that the resistance of bonding wire was a dominant component. The estimated resistance of the SFTR was 7.2 mΩ, corresponding to a lower cut-off frequency of 11.7 Hz.

  3. Mobile HTS SQUID System for Nondestructive Evaluation of Aircraft Structures

    NASA Astrophysics Data System (ADS)

    Krause, Hans-Joachim; Hohmann, Rainer; Grueneklee, Michael; Zhang, Yi; Braginski, Alex I.

    1997-03-01

    For the detection of deep-lying flaws in aircraft structures, a mobile eddy-current system is being developed in conjunction with a high-temperature superconductor (Yba_2Cu_3O_7) thin-film HTS SQUID gradiometer. The challenge is to operate the SQUID sensor during movement in strong ambient fields, independent of orientation. A planar rf double hole gradiometer with a gradient sensitivity of 500 fT/(cm √Hz) was designed for that purpose. Two different cooling concepts were successfully implemented: the SQUID operation in the vacuum region of a lightweight nitrogen cryostat, constructed for operation in any orientation, and the use of a commercial Joule-Thomson cryocooler for liquid-nitrogen-free SQUID cooling. With a SQUID integration scheme using a sapphire cold finger, motion-related additional noise is nearly eliminated. Using a system equipped with a differential eddy current excitation, two-dimensional scans were performed to find fatigue cracks and corrosion pits hidden below several layers of aluminum. For demonstration in the Lufthansa maintenance facility at Frankfurt Airport, the system was used to detect flaws in aircraft wheels. Work in progress includes developing longer base gradiometers for detection of deep flaws.

  4. Eddy current nondestructive material evaluation based on HTS SQUIDs

    NASA Astrophysics Data System (ADS)

    Mück, M.; Kreutzbruck, M. v.; Baby, U.; Tröll, J.; Heiden, C.

    1997-08-01

    High Temperature Superconductor (HTS) Superconducting Quantum Interference Devices (SQUIDs) are promising sensors for applications in eddy current nondestructive evaluation (NDE). Due to their high field sensitivity at low frequencies, they are especially suitable for applications, where a large penetration depth is required. We have investigated two different SQUID-based NDE systems, one of which is optimised for testing felloes of aircraft wheels. The second system allows for testing planar structures using a motorised x-y-stage, which moves the cryostat above the planar samples. As sensors 3 GHz rf SQUIDs made from YBCO were used, having a field noise of about 1 pT/√Hz. This results in a dynamic range of our SQUID system of about 155 dB/√Hz. In most cases, the SQUIDs have been cooled by immersing them in liquid nitrogen. We have however also developed a cryosystem, which allows for cooling the sensors by a Ne-gas flow. In planar test structures we could detect flaws with lengths of 10 mm, having a height of 0.6 mm in a depth of 13 mm. In aircraft felloes, flaws located at the inner surface of the felloe (thickness 8 mm) were easily detectable despite a high static background field of up to 0.5 G caused by ferromagnetic structures inside the felloe. For flaws in a depth of 5 mm, the spatial resolution of both systems was about 8 mm without applying image postprocessing.

  5. Two Methods for a First Order Hardware Gradiometer Using Two HTS SQUID's

    SciTech Connect

    Espy, M.A.; Flynn, E.R.; Kraus, R.H., Jr.; Matlachov, A.

    1998-09-15

    Two different systems for noise cancellation (first order gradiometers) have been developed using two similar high temperature superconducting (HTS) SQUIDs. ''Analog'' gradiometry is accomplished in hardware by either (1) subtracting the signals from the sensor and background SQUIDs at a summing amplifier (parallel technique) or (2) converting the inverted background SQUID signal to a magnetic field at the sensor SQUID (series technique). Balance levels achieved are 2000 and 1000 at 20 Hz for the parallel and series methods respectively. The balance level as a function of frequency is also presented. The effect which time delays in the two sets of SQUID electronics have on this balance level is presented and discussed.

  6. Two methods for a first order hardware gradiometer using two HTS SQUIDs

    SciTech Connect

    Espy, M.A.; Flynn, E.R.; Kraus, R.H. Jr.; Matlachov, A.

    1998-12-31

    Two different systems for noise cancellation (first order gradiometers) have been developed using two similar high temperature superconducting (HTS) SQUIDs. Analog gradiometry is accomplished in hardware by either (1) subtracting the signals from the sensor and background SQUIDs at a summing amplifier (parallel technique) or (2) converting the inverted background SQUID signal to a magnetic field at the sensor SQUID (series technique). Balance levels achieved are 2000 and 1000 at 20 Hz for the parallel and series methods respectively. The balance level as a function of frequency is also presented. The effect which time delays in the two sets of SQUID electronics have on this balance level is presented and discussed.

  7. Electronic gradiometry for NDE in an unshielded environment with stationary and moving HTS SQUIDs

    NASA Astrophysics Data System (ADS)

    Carr, C.; Cochran, A.; Kuznik, J.; McKirdy, D. McA.; Donaldson, G. B.

    Difficulties in the fabrication of multilayer high-temperature superconductor (HTS) devices have led to recent interest in the use of simpler HTS SQUID magnetometers in electronic gradiometers. One application of such systems is electromagnetic non-destructive evaluation. We have developed a prototype two-SQUID system and we present recent results in this paper. We first demonstrate the level of interference suppression by comparing magnetometer and gradiometer signals. Then we present several results taken conventionally with the HTS SQUIDs stationary above moving specimens and, for the first time, with the SQUIDs unshielded in motion above stationary specimens. The specimens comprise a pair of wires in a return current loop as a calibration source, and an aircraft-grade aluminium plate with fine slits mimicking fatigue cracks, first exposed and then covered with an additional aluminium sheet to simulate internal flaws. These results are an important, though by no means final, step towards practical non-destructive evaluation of real test subjects with HTS SQUIDs.

  8. SQUID Multiplexers for Cryogenic Detector Arrays

    NASA Technical Reports Server (NTRS)

    Irwin, Kent; Beall, James; Deiker, Steve; Doriese, Randy; Duncan, William; Hilton, Gene; Moseley, S. Harvey; Reintsema, Carl; Stahle, Caroline; Ullom, Joel; Vale, Leila

    2004-01-01

    SQUID multiplexers make it possible to build arrays of thousands of cryogenic detectors with a manageable number of readout channels. We are developing time-division SQUID multiplexers based on Nb trilayer SQUIDs to read arrays of superconducting transition-edge sensors. Our first-generation, 8-channel SQUID multiplexer was used in FIBRE, a one-dimensional TES array for submillimeter astronomy. Our second-generation 32-pixel multiplexer, based on an improved architecture, has been developed for instruments including Constellation-X, SCUBA-2, and solar x-ray astronomy missions. SCUBA-2, which is being developed for the James Clerk Maxwell Telescope, will have more than 10,000 pixels. We are now developing a third-generation architecture based on superconducting hot-electron switches. The use of SQUID multiplexers in instruments operating at above 2 K will also be discussed.

  9. Non-destructive inspection using HTS SQUID on aluminum liner covered by CFRP

    NASA Astrophysics Data System (ADS)

    Hatsukade, Y.; Yotsugi, K.; Sakaguchi, Y.; Tanaka, S.

    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. An investigation of pinch welds using HTS SQUIDs

    NASA Astrophysics Data System (ADS)

    Carr, Chris; Espy, Michelle A.; Urbaitis, Algis V.; Kraus, Robert H., Jr.

    2006-05-01

    To contain high-pressure gases inside a pressure vessel a seal is often made in a thin-walled tube, known as the stem tube, that connects the gas reservoir and the vessel. This seal can be achieved through the use of a resistance pinch weld that forms with only a limited amount of melting occurring. The lack of melting makes applying traditional post-weld nondestructive evaluation (NDE) techniques extremely difficult. The welds of interest here are made from 304L stainless steel (typically 3.8 mm diameter and 38 mm long) and have a non-uniform geometry that does not inherently lend itself to either eddy current or static field SQUID-based measurement techniques. We perform these NDE measurements with both the sample and the SQUID located inside local electromagnetic shielding. SQUID data are presented as individual time series traces for a set of welds that were fabricated using a broad range of fabrication parameters, and a comparison is made between the SQUID-based results and the known parameters. With the limited spatial resolution offered by our present SQUID system, it is not clear if weld quality can be evaluated from purely SQUID-based results.

  11. SQUID array for magnetic inspection of prestressed concrete bridges

    NASA Astrophysics Data System (ADS)

    Krause, H.-J.; Wolf, W.; Glaas, W.; Zimmermann, E.; Faley, M. I.; Sawade, G.; Mattheus, R.; Neudert, G.; Gampe, U.; Krieger, J.

    2002-03-01

    For detection of tendon ruptures in prestressed members of bridges, a four-channel SQUID system was developed. The tendons are magnetized by scanning a yoke electromagnet over the concrete surface along the hidden member. Four HTS dc-SQUID magnetometers with ramp-type junctions, optimized for high-field performance, are mounted in an orientation-independent liquid nitrogen cryostat. The SQUIDs are integrated as a linear array within the yoke and operated in magnetic fields up to 15 mT, recording the stray field during magnetization as well as the remanent field after switching off the excitation. Unwanted signals from stirrups of the mild steel reinforcement are suppressed with two types of techniques: either the comparison of remanent field signals after changing the magnetization direction of the stirrups, or a best fit of typical stirrup signals to the stray field signal and their subtraction. Subsequent correlation analysis with the dipolar signal of a typical void yields rupture signal amplitudes. A finite element program was written to simulate stray field and remanent field traces of typical steel configurations. Excellent agreement with measured data was found. Results of measurements on a prestressed highway bridge are presented. Signal amplitudes above the threshold values were verified as originating from ruptures of the steel tendon by opening the bridge deck.

  12. Development of Non-destructive Evaluation System Using an HTS-SQUID Gradiometer with an External Pickup Coil

    NASA Astrophysics Data System (ADS)

    Kawano, J.; Kawauchi, S.; Ishikawa, F.; Tanabe, K.

    We are developing a new eddy-current non-destructive evaluation (NDE) system using a high-temperature superconducting quantum interference device (HTS-SQUID) gradiometer with the aim of applying it to power plants. Electric power facilities such as ducts and vessels are generally untransportable because of their size, and thus it is difficult to apply a conventional SQUID NDE system. The new NDE system employs an external Cu pickup coil which is supposed to be driven flexibly by a robot arm at room temperature and an HTS-SQUID chip which is placed in a magnetically shielded vessel. In the present research, we investigated the performance of an HTS-SQUID sensor connected with external pickup coils before mounting them to a robot arm. By varying the Cu coil conditions such as their sizes, the number of turns, and the diameter of wire, we qualitatively evaluated the frequency dependence of the effective area and the cutoff frequency.

  13. Development of HTS-SQUID magnetometer system with high slew rate for exploration of mineral resources

    NASA Astrophysics Data System (ADS)

    Hato, T.; Tsukamoto, A.; Adachi, S.; Oshikubo, Y.; Watanabe, H.; Ishikawa, H.; Sugisaki, M.; Arai, E.; Tanabe, K.

    2013-11-01

    For the transient electromagnetic (TEM) method using a high-temperature superconducting interference device (HTS-SQUID), we have developed a magnetometer system with a wide dynamic range, a high slew rate, and superior transportability. To achieve high tolerance to a higher excitation magnetic field, we utilized a SQUID magnetometer containing ramp-edge junctions with La0.1Er0.95Ba1.95Cu3Oy and SmBa2Cu3Oy electrode layers, which was fabricated by using an HTS multi-layer fabrication technique. To operate the magnetometer stably in a rapidly changing magnetic field, we chose the proper materials for the RF shield of liquid nitrogen (LN2) glass Dewar and cables. The white noise level and the slew rate of the system were measured to be 30 fT Hz-1/2 and 10.5 mT s-1, respectively. The resultant signal-to-noise ratio was higher than that of the previous system and improved the exploration depth, which was successfully demonstrated in field tests. The weight of the Dewar, which retains the LN2 for 17 h, is 2.5 kg. The total weight of our system including the LN2 Dewar, a probe with a flux-locked loop (FLL) circuit, a battery, a receiver, and a 30 m-long cable between the FLL and the receiver is as low as 25.6 kg.

  14. Performance of multiplexed SQUID readout for Cryogenic Sensor Arrays

    NASA Astrophysics Data System (ADS)

    Chervenak, J. A.; Grossman, E. N.; Irwin, K. D.; Martinis, John M.; Reintsema, C. D.; Allen, C. A.; Bergman, D. I.; Moseley, S. H.; Shafer, R.

    2000-04-01

    We report on the implementation of a multiplexer that uses superconducting quantum interference devices (SQUIDs) to read out low-impedance cryogenic detectors. Using prototype chips, a circuit was built which interfaces eight input SQUID channels with a close-packed array of eight transition-edge sensor (TES) infrared bolometers. Circuit elements were measured and crosstalk specifications are reported. Digital feedback is employed to flux-lock a single element in the array of SQUIDs.

  15. A HTS dc SQUID-NMR: fabrication of the SQUID and application to low-field NMR for fruit quality detection

    NASA Astrophysics Data System (ADS)

    Isingizwe Nturambirwe, J. Frédéric; Perold, Willem J.; Opara, Linus U.

    2014-06-01

    Superconducting Quantum Interference Devices (SQUIDs) have made the detection of low-field (LF) and ultra-low field nuclear magnetic resonance (ULF-NMR) a reality. The latter has been proven to be a potential tool for non-destructive quality testing of horticultural products, amongst many other applications. High-Temperature Superconductor (HTS) dc SQUIDS are likely to allow for the development of not only low-cost NMR systems but also prototypes that are mobile and easily maintainable. A HTS dc SQUID was manufactured on an YBCO thin film, using a novel laser based lithography method. The lithography was implemented by a new laser system developed in-house, as a model of low-cost lithography systems. The junctions of the dc SQUID were tested and displayed normal I-V characteristics in the acceptable range for the application. In order to determine the viability of low-field NMR for non-destructive quality measurement of horticultural products, a commercial HTS dc SQUID-NMR system was used to measure quality parameters of banana during ripening. The trend of color change and sugar increase of the banana during ripening were the most highly correlated attributes to the SQUID-NMR measured parameter, average T1 (spin-lattice relaxation time). Further studies were done, that involved processing of the NMR signal into relaxation time resolved spectra. A spectral signature of banana was obtained, where each peak is a T1 value corresponding to a proton pool, and is reported here. These results will potentially lead to deeper understanding of the quality of the samples under study.

  16. Nondestructive evaluation of braided carbon fiber composites with artificial defect using HTS-SQUID gradiometer

    NASA Astrophysics Data System (ADS)

    Shinyama, Y.; Yamaji, T.; Hatsukade, Y.; Takai, Y.; Aly-Hassan, M. S.; Nakai, A.; Hamada, H.; Tanaka, S.

    2011-11-01

    Braided carbon fiber reinforced plastics (CFRPs) are one of multifunctional materials with superior properties such as mechanical strength to normal CFRPs since the braided CFRPs have continuous fiber bundles. In this paper, we applied the current-injection-based nondestructive evaluation (NDE) method using a HTS-SQUID gradiometer to the braided CFRP for the detection of the breakage of the bundles. We prepared planar braided CFRP samples with and without artificial cracks of 1 and 2 mm lengths, and measured the current density distribution above the samples using the NDE method. In the measurement results, not only a few completely-cut bundles but also the additional partially-cut bundles were detected from decrease in the measured current density along the cut bundle around the cracks. From these results, we showed that it is possible to inspect a few partially-cut bundles in the braided CFRPs by the NDE method.

  17. Foetal magnetocardiography with a multi-channel HTS rf SQUID gradiometer

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Wolters, N.; Lomparski, D.; Zander, W.; Banzet, M.; Schubert, J.; Krause, H.-J.; Geue, D.; van Leeuwen, P.

    2006-05-01

    Foetal magnetocardiography (fMCG) is a promising technique for prenatal cardiac diagnosis. In this paper, we discuss the special requirements of a system for fMCG measurements. A SQUID system incorporating five HTS rf SQUID magnetometers has been developed and constructed. Four magnetometers are arranged at the bottom of the cryostat in a 4 cm × 4 cm square configuration. One reference magnetometer is located 20 cm above the plane to form four first-order axial gradiometers with the four bottom magnetometers. The magnetometer with a 18 mm diameter flux focuser, which reaches a field sensitivity of 20-30 fT Hz-1/2, proved sufficient for recording foetal magnetocardiograms in a magnetically shielded room. The cardiac activities of two foetuses (31st and 33rd weeks of gestation) were recorded in 90 Hz bandwidth. The foetal QRS peak signals ranged from 4 to 7 pT and could easily be identified in the real-time gradiometer outputs with a signal-to-noise ratio of up to five. Furthermore, the averaged fMCG data enabled the determination of de- and repolarization time intervals. Overall, the fMCG signals proved of sufficient quality to perform foetal heart diagnostics.

  18. ULF-NMR system using HTS-SQUID and permanent magnet

    NASA Astrophysics Data System (ADS)

    Fukumoto, Shohei; Tsunaki, Shingo; Chigasaki, Takumi; Hatsukade, Yoshimi; Tanaka, Saburo

    2013-01-01

    We have constructed an ultra-low field (ULF) nuclear magnetic resonance (NMR)/magnetic resonance imaging (MRI) system using an HTS-rf-SQUID and room-temperature electromagnets in a magnetically shielded room (MSR). In this study, in order to improve the signal to noise ratio (S/N) of the system, we introduced a permanent magnet instead of the electromagnet for pre-polarizing the sample to enhance the pre-polarizing field (Bp). The cylindrical permanent magnet of 270 mT was used to magnetize a water sample for several seconds outside the MSR and about 1.5 m away from the SQUID. We constructed an instrument to transfer the magnetized sample from the permanent magnet to under the SQUID in 0.5 s. Since the non-adiabatic condition cannot be kept in such sample transfer scheme, an AC pulse coil to apply an AC pulse field BAC to rotate the magnetization moments for π/2 was introduced to measure a free induction decay (FID) signal from the sample. By this system, we obtained an NMR signal from the water sample of 10 ml while applying a static field of 45 μT and π/2 pulse after the transfer. The S/N of the NMR spectrum was about 100 by a single shot, which was 10 times larger than that obtained with the electromagnet of 32 mT. In addition, we demonstrated the measurements of the longitudinal relaxation time (T1) and the spin echo signal of the water sample by the system.

  19. Development of a colorimetric sensor array for squid spoilage assessment.

    PubMed

    Zaragozá, Patricia; Fuentes, Ana; Ruiz-Rico, María; Vivancos, José-Luis; Fernández-Segovia, Isabel; Ros-Lis, José V; Barat, José M; Martínez-Máñez, Ramón

    2015-05-15

    The aim of this work was to develop and evaluate a rapid, easy-to-use optoelectronic system for the shelf-life assessment of squid in cold storage. For this purpose, an optoelectronic nose was designed, which consisted of an array containing six sensing materials prepared by combining different dyes and two inorganic supports (aluminium oxide and silica gel). Samples were packaged with the colorimetric array and kept in cold storage for 12 days. Squid spoilage was monitored simultaneously by the colorimetric array and by the physico-chemical and microbial analyses during storage. Samples exceeded the acceptability limits for microbial counts on the third day. PCA analysis carried out with CIELab showed that the colorimetric array was able to discriminate between fresh squid fit for consumption and spoiled squid. The statistical models obtained by PLS, with the optoelectronic nose, successfully predicted CO2 and O2 content in the headspace as well as microbial growth. PMID:25577086

  20. Robot-arm-based NDE of hydrogen fuel tank using a 3D-movable HTS-SQUID gradiometer

    NASA Astrophysics Data System (ADS)

    Hatsukade, Y.; Hayashi, K.; Tanaka, S.; Tanabe, K.

    2010-06-01

    In this study, we constructed a robot-arm-based SQUID-NDE system utilizing a novel HTS-SQUID gradiometer with ramp-edge Josephson junctions for hydrogen fuel tank inspection, and developed an automatic 3D-scanning program. A cylindrical hydrogen fuel tank with a double-layer structure, in which a 3mm-thick Al liner was reinforced by a 3mm-thick carbon-fibre reinforced plastic (CFRP) cover, was prepared. The tank had a 10-mm-long through crack in the Al liner made by pressure cycle test. To inspect the tank using the SQUID-NDE system, we adopted a low-frequency eddy current technique that enables to excite deep part in the Al liner. By applying an excitation field of 7.5 μT at 0.4 to 10 kHz to the tank from a double-D coil, the tank was scanned by the system while moving the HTS-SQUID gradiometer along curved surface of the tank in magnetically unshielded environment. Magnetic responses from the deep-lying crack in the tank were successfully detected by the system.

  1. Two-stage series array SQUID amplifier for space applications

    NASA Astrophysics Data System (ADS)

    Tuttle, J. G.; DiPirro, M. J.; Shirron, P. J.; Welty, R. P.; Radparvar, M.

    We present test results for a two-stage integrated SQUID amplifier which uses a series array of d.c. SQUIDS to amplify the signal from a single input SQUID. The device was developed by Welty and Martinis at NIST and recent versions have been manufactured by HYPRES, Inc. Shielding and filtering techniques were employed during the testing to minimize the external noise. Energy resolution of 300 h was demonstrated using a d.c. excitation at frequencies above 1 kHz, and better than 500 h resolution was typical down to 300 Hz.

  2. Prediction of Initiation Site of Destruction of Flat Braided Carbon Fiber Composites Using HTS-SQUID Gradiometer

    NASA Astrophysics Data System (ADS)

    Shinyama, Y.; Hatsukade, Y.; Tanaka, S.; Takai, Y.; Aly-Hassan, M. S.; Nakai, A.; Hamada, H.

    Carbon fiber reinforced polymers (CFRPs) are composite materials with lightweight and high specific strength. As the braided CFRPs have continuous carbon-fiber bundles in their longitudinal direction, they are stronger than conventional CFRPs. In this study, we applied a current-injection-based NDE method using a HTS-SQUID gradiometer to the flat braided CFRPs with and without carbon nanotubes (CNTs), and estimated conditions of the carbon fibers while applying a step-by-step tensile load to the CFRPs. From the results, a possibility to predict an initiation site of the destruction in the braided CFRPs was demonstrated.

  3. nSQUID arrays as conveyers of quantum information

    SciTech Connect

    Deng, Qiang; Averin, D. V.

    2014-12-15

    We have considered the quantum dynamics of an array of nSQUIDs—two-junction SQUIDs with negative mutual inductance between their two arms. Effective dual-rail structure of the array creates additional internal degree of freedom for the fluxons in the array, which can be used to encode and transport quantum information. Physically, this degree of freedom is represented by electromagnetic excitations localized on the fluxon. We have calculated the spatial profile and frequency spectrum of these excitations. Their dynamics can be reduced to two quantum states, so that each fluxon moving through the array carries with it a qubit of information. Coherence properties of such a propagating qubit in the nSQUID array are characterized by the dynamic suppression of the low-frequency decoherence due to the motion-induced spreading of the noise spectral density to a larger frequency interval.

  4. nSQUID arrays as conveyers of quantum information

    NASA Astrophysics Data System (ADS)

    Deng, Qiang; Averin, D. V.

    2014-12-01

    We have considered the quantum dynamics of an array of nSQUIDs—two-junction SQUIDs with negative mutual inductance between their two arms. Effective dual-rail structure of the array creates additional internal degree of freedom for the fluxons in the array, which can be used to encode and transport quantum information. Physically, this degree of freedom is represented by electromagnetic excitations localized on the fluxon. We have calculated the spatial profile and frequency spectrum of these excitations. Their dynamics can be reduced to two quantum states, so that each fluxon moving through the array carries with it a qubit of information. Coherence properties of such a propagating qubit in the nSQUID array are characterized by the dynamic suppression of the low-frequency decoherence due to the motion-induced spreading of the noise spectral density to a larger frequency interval.

  5. Development of a Two-Dimensional Micro-SQUID Array for Investigation of Magnetization Spatial Distribution

    NASA Astrophysics Data System (ADS)

    Sakuma, Daisuke; Shinozaki, Tomoya; Nago, Yusuke; Ishiguro, Ryosuke; Kashiwaya, Satoshi; Nomura, Shintaro; Kono, Kimitoshi; Takayanagi, Hideaki

    2016-05-01

    We developed a two-dimensional array of superconducting quantum interference devices (SQUIDs) for investigation of fine spatial distribution of magnetization in superconducting Sr2RuO4. Micrometer-sized SQUIDs based on homogeneously formed Al/AlOx/Al tunnel-type Josephson junctions were fabricated using shadow evaporation technique. Unnecessary electrodes formed by the shadow evaporation were removed by inductively coupled plasma reactive ion etching, in order to realize a dense array of SQUIDs. We measured the magnetic modulation of the maximum Josephson current of each SQUID in the array and evaluated the interaction among the SQUIDs.

  6. High-Resolution Displacement Sensor Using a SQUID Array Amplifier

    NASA Technical Reports Server (NTRS)

    Chui, Talso; Penanen, Konstantin; Barmatz, M.; Paik, Ho Jung

    2004-01-01

    Improvement in the measurement of displacement has profound implications for both exploration technologies and fundamental physics. For planetary exploration, the new SQUID-based capacitive displacement sensor will enable a more sensitive gravity gradiometer for mapping the interior of planets and moons. A new concept of a superfluid clock to be reported by Penanen and Chui at this workshop is also based on a high-resolution displacement sensor. Examples of high-impact physics projects that can benefit from a better displacement sensor are: detection of gravitational waves, test of the equivalence principle, search for the postulated "axion" particle, and test of the inverse square law of gravity. We describe the concept of a new displacement sensor that makes use of a recent development in the Superconducting Quantum Interference Device (SQUID) technology. The SQUID array amplifier, invented by Welty and Martinis (IEEE Trans. Appl. Superconductivity 3, 2605, 1993), has about the same noise as a conventional SQUID; however, it can work at a much higher frequency of up to 5 MHz. We explain how the higher bandwidth can be translated into higher resolution using a bridge-balancing scheme that can simultaneously balance out both the carrier signal at the bridge output and the electrostatic force acting on the test mass.

  7. Scanning SQUID microscopy of SFS π-Josephson junction arrays

    NASA Astrophysics Data System (ADS)

    Stoutimore, M. J. A.; Oboznov, V. A.

    2005-03-01

    We use a Scanning SQUID Microscope to image the magnetic flux distribution in arrays of SFS (superconductor-ferromagnet-superconductor) Josephson junctions. The junctions are fabricated with barrier thickness such that they undergo a transition to a π-junction state at a temperature Tπ 2-4 K. In arrays with cells that have an odd number of π-junctions, we observe spontaneously generated magnetic flux in zero applied magnetic field. We image both fully-frustrated arrays and arrays with non-uniform frustration created by varying the number of π-junctions in the cells. By monitoring the onset of spontaneous flux as a function of temperature near Tπ,^ we estimate the uniformity of the junction critical currents.

  8. Superconductive combinational logic circuit using magnetically coupled SQUID array

    NASA Astrophysics Data System (ADS)

    Yamanashi, Y.; Umeda, K.; Sai, K.

    2010-11-01

    In this paper, we propose the development of superconductive combinational logic circuits. One of the difficulties in designing superconductive single-flux-quantum (SFQ) digital circuits can be attributed to the fundamental nature of the SFQ circuits, in which all logic gates have latching functions and are based on sequential logic. The design of ultralow-power superconductive digital circuits can be facilitated by the development of superconductive combinational logic circuits in which the output is a function of only the present input. This is because superconductive combinational logic circuits do not require determination of the timing adjustment and clocking scheme. Moreover, semiconductor design tools can be used to design digital circuits because CMOS logic gates are based on combinational logic. The proposed superconductive combinational logic circuits comprise a magnetically coupled SQUID array. By adjusting the circuit parameters and coupling strengths between neighboring SQUIDs, fundamental combinational logic gates, including the AND, OR, and NOT gates, can be built. We have verified the accuracy of the operations of the fundamental logic gates by analog circuit simulations.

  9. Multichannel DC SQUID sensor array for biomagnetic applications

    SciTech Connect

    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. )

    1991-03-01

    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{sup 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).

  10. Single SQUID frequency-domain multiplexer for large bolometer arrays

    SciTech Connect

    Yoon, Jongsoo; Clarke, John; Gildemeister, J.M.; Lee, Adrian T.; Myers, M.J.; Skidmore, J.T.; Richards, P.L.; Spieler, H.G.

    2001-08-20

    We describe the development of a frequency-domain superconducting quantum interference device (SQUID) multiplexer which monitors a row of low-temperature sensors simultaneously with a single SQUID. Each sensor is ac biased with a unique frequency and all the sensor currents are added in a superconducting summing loop. A single SQUID measures the current in the summing loop, and the individual signals are lock-in detected after the room temperature SQUID electronics. The current in the summing loop is nulled by feedback to eliminate direct crosstalk. We have built an eight-channel prototype and demonstrated channel separation and signal recovery.

  11. Monolithic HTS microwave phase shifter and other devices

    NASA Astrophysics Data System (ADS)

    Jackson, Charles M.; Kobayashi, June H.; Guillory, Emery B.; Pettiette-Hall, Claire; Burch, John F.

    1992-08-01

    We describe a monolithic high-temperature superconductor (HTS) phase shifter based on the distributed Josephson inductance (DJI) design integrated monolithically into a 10-GHz microstrip line. This microwave circuit incorporates greater than 1000 HTS RF SQUIDS. Recent data demonstrate the performance of this broadband HTS circuit. We observed phase shifts greater than 150 deg in resonant structures, and 20 deg in broadband circuits. The nonlinear inductance of the superconducting transmission line can be used for other novel applications, including parametric amplification. A comparison of the DJI circuit to a series array of Josephson elements (used for pulse sharpening) will contrast these two new and exciting nonlinear transmission line circuits.

  12. SiGe Integrated Circuit/SQUID Hybrid Cryogenic Multiplexer for Superconducting Bolometer Array

    NASA Astrophysics Data System (ADS)

    Prêle, D.; Voisin, F.; Oger, R.; Chapron, C.; Bréelle, E.; Piat, M.

    2009-12-01

    The development of large superconducting bolometer (Transition Edge Sensor: TES) arrays requires ultra low noise amplification and multiplexing electronics. The use of a first transducer stage such as a SQUID (Superconducting QUantum Interference Device) allows ultimate performance in terms of noise. However, the linearization of the SQUID characteristic requires low noise amplification. Furthermore, to realize a time domain multiplexer with SQUIDs, switched biasing is also needed. We have designed an Integrated Circuit (IC) in standard BiCMOS SiGe technology for the readout and the control of a SQUID multiplexer. It includes a low noise amplifier with multiplexed inputs, switched current sources for SQUIDs, and digital circuit for the addressing with only one room temperature clock signal. We have successfully tested this integrated circuit down to 2 K. To validate the operation of a SQUID multiplexer controlled by this SiGe cryogenic IC, we have developed a 2×2 SQUID hybrid demonstrator. It consists of four commercial SQUIDs connected to a SiGe IC.

  13. Characterization of large two-dimensional YBa2Cu3O7–δ SQUID arrays

    NASA Astrophysics Data System (ADS)

    Taylor, B. J.; Berggren, S. A. E.; O’Brien, M. C.; deAndrade, M. C.; Higa, B. A.; Leese de Escobar, A. M.

    2016-08-01

    Large two-dimensional SQUID arrays were made using the step-edge Josephson junction process. The performance of the arrays is analyzed with respect to determining the conditions under which the optimal performance is achieved. We find that optimization of the field-voltage transfer function V B is reached at a specific temperature and device current bias point, and arrive at an empirical expression describing the dependence of V B on the critical current and dynamic resistance of the SQUID array and as a function of temperature. The empirical expression for V B of the SQUID arrays is similar to that given by well known theoretical models for a single SQUID.

  14. Cryogenic time-domain multiplexer based on SQUID arrays and superconducting/normal conducting switches

    NASA Astrophysics Data System (ADS)

    Beev, N.; Kiviranta, M.; van der Kuur, J.; Bruijn, M.; Brandel, O.; Linzen, S.; Fritzsch, L.; Ahoranta, J.; Penttilä, J.; Roschier, L.

    2014-05-01

    We have demonstrated the operation of a 12-channel Beyer-style SQUID-based time domain multiplexer. It was manufactured using a fabrication process that is cross-compatible between VTT and IPHT-Jena. The multiplexer consists of twelve 12-SQUID series arrays, each shunted by a Zappe-style interferometer array acting as a flux-controlled superconducting/normal conducting switch. By keeping all switches but one in the superconducting state, it is possible to select one active readout channel at a time. A flux feedback coil common to all SQUID arrays allows realization of a flux-locked loop. We present characteristics of the multiplexer and measurement data from experiments with a 25-pixel X-ray calorimeter array operated at T < 100 mK in a dilution refrigerator.

  15. The Multiplexed SQUID TES array at Ninety Gigahertz (MUSTANG)

    NASA Astrophysics Data System (ADS)

    Korngut, Phillip M.

    The Multiplexed SQUID/TES Array at Ninety Gigahertz (MUSTANG) is a bolometric continuum imaging camera designed to operate at the Gregorian focus of the 100 m Green Bank Telescope (GBT) in Pocahontas county, West Virginia. The combination of the GBT's large collecting area and the 8 x 8 array of transition edge sensors at the heart of MUSTANG allows for deep imaging at 10'' resolution at 90 GHz. The MUSTANG receiver is now a facility instrument of the National Radio Astronomy Observatory available to the general astronomical community. The 3.3 mm continuum passband is useful to access a large range of Galactic and extra-Galactic astrophysics. Sources with synchrotron, free-free and thermal blackbody emission can be detected at 3.3 mm. Of particular interest is the Sunyaev Zel'dovich effect in clusters of galaxies, which arises from the inverse Compton scattering of CMB photons off hot electrons in the intra-cluster medium. In the MUSTANG band, the effect is observationally manifested as an artificial decrement in power on the sky in the direction of the cluster. There have been many experiments in the past two decades dedicated to measurements of the SZE, however, nearly all of them were accomplished with angular resolution larger than ˜ 1'. The massive primary of the GBT enables measurements of the SZE on 10'' scales. This provides a new technique to map pressure substructure in the plasma atmospheres of merging clusters of galaxies. By analyzing MUSTANG data along side X-ray data, spatially resolved measurements of the temperature, density and pressure of the ICM can be performed which can be used to infer the physics governing major mergers. This thesis details the design, commissioning and operation of the various components which comprise the MUSTANG receiver. This includes the sub-kelvin cryogenic cooling, the time domain multiplexed readout electronics and the array of transition edge sensor bolometers. Laboratory characterization of the detector array is

  16. Development of multielement SQUID arrays for magnetic source imaging. Final report

    SciTech Connect

    Hassenzahl, W.V.; Casper, T.A.; Miller, D.E.

    1995-06-01

    Superconducting quantum interference devices (SQUIDs) were initially developed in the late 1960s as biomagnetic detectors to monitor electrical activity in the body. Research in this area has increased in recent years as electronics and computer diagnositcs have improved. The basis of this proposal was to asses: (1) the advantages of using this technique over other technologies and (2) the requirements for development of a complete system that would advance the state of the art. In our assessment of this technology, we collaborated with the Medical School at the University of California, San Francisco (UCSF), General Electric (GE), Biomagnetic Technologies (BTi), and Conductus, each of which has unqiue expertise in biomedical applications. UCSF is one of the foremost clinical institutions in the US developing imaging techniques. GE is the primary US supplier of medical imaging systems. Conductus is the major US supplier of SQUIDs and BTi is a developer of SQUID array systems.

  17. Time-division SQUID multiplexer for the readout of X-ray microcalorimeter arrays

    NASA Astrophysics Data System (ADS)

    Doriese, W. B.; Beall, J. A.; Beyer, J.; Deiker, S.; Ferreira, L.; Hilton, G. C.; Irwin, K. D.; Martinis, J. M.; Nam, S. W.; Reintsema, C. D.; Ullom, J. N.; Vale, L. R.; Xu, Y.

    2004-03-01

    Large-format (>1000 pixel) arrays of transition-edge sensors are being developed for applications ranging from X-ray materials analysis to submillimeter (SCUBA-2, ACT, SAFIRE) and X-ray (Constellation-X) astronomy. Cryogenic multiplexing allows instrumentation of these large detector arrays with a manageable number of wires and readout channels. We describe a SQUID-based, time-division multiplexer for X-ray microcalorimeter arrays, including a three-stage SQUID amplifier chain and room-temperature digital-feedback electronics. The prototype system has passed two milestone tests. First, energy resolution of 6.6 eV obtained from measuring 5.2 keV joule-heat pulses was not degraded by multiplexing 2, 4, or 8 biased detectors. Second, 55Fe spectra obtained with four multiplexed detectors showed essentially the same resolution as those obtained from the same detectors while not multiplexed.

  18. HTS magnetometers for fetal magnetocardiography.

    PubMed

    Li, Z; Wakai, R T; Paulson, D N; Schwartz, B

    2004-01-01

    High temperature superconducting (HTS) SQUID sensors have adequate magnetic field sensitivity for adult magnetocardiography (MCG) measurements, but it remains to be seen how well they perform for fetal MCG (fMCG), where the heart signals are typically ten times smaller than the adult signals. In this study, we assess the performance of a prototype HTS SQUID system; namely, a three-SQUID gradiometer formed from three vertically-aligned HTS dc-SQUID magnetometers integrated into a fiberglass liquid nitrogen dewar of diameter 12.5 cm and height 30 cm. Axial gradiometers with short or long baseline, as well as a second order gradiometer, can be formed out of these magnetometers via electronic subtraction. The calibrated magnetometer sensitivities at 1 kHz are 109 fT/square root of Hz, 155 fT/square root of Hz and 51 fT/square root of Hz. Direct comparison is made between the HTS SQUID system and a LTS SQUID system by making recordings with both systems during the same session on adult and fetal subjects. Although the fMCG could be resolved with the HTS SQUID system in most near-term subjects, the signal-to-noise ratio was relatively low and the system could not be operated outside of a shielded room. PMID:16012655

  19. Development of a Microwave SQUID-Multiplexed TES Array for MUSTANG-2

    NASA Astrophysics Data System (ADS)

    Stanchfield, S. M.; Ade, P. A. R.; Aguirre, J.; Brevik, J. A.; Cho, H. M.; Datta, R.; Devlin, M. J.; Dicker, S. R.; Dober, B.; Egan, D.; Ford, P.; Hilton, G.; Hubmayr, J.; Irwin, K. D.; Marganian, P.; Mason, B. S.; Mates, J. A. B.; McMahon, J.; Mello, M.; Mroczkowski, T.; Romero, C.; Tucker, C.; Vale, L.; White, S.; Whitehead, M.; Young, A. H.

    2016-07-01

    MUSTANG-2 is a 90 GHz feedhorn-coupled, microwave SQUID-multiplexed TES bolometer array in the final stages of development for operation on the 100-m Robert C. Byrd Green Bank Telescope. We present the camera design and report the performance during the first season of observation, in which 64 of the available 215 pixels in the focal plane were populated. We highlight the microwave multiplexing readout technology, which is envisioned as a path to read out the next generation of large pixel-count cryogenic focal planes. In this regard, MUSTANG2 is a pathfinder for this multiplexing technology. We present noise spectra which show no detector noise degradation when read out with microwave SQUID multiplexing, and we present first light images of Jupiter and M87, which demonstrate the end-to-end system performance.

  20. Development of a Microwave SQUID-Multiplexed TES Array for MUSTANG-2

    NASA Astrophysics Data System (ADS)

    Stanchfield, S. M.; Ade, P. A. R.; Aguirre, J.; Brevik, J. A.; Cho, H. M.; Datta, R.; Devlin, M. J.; Dicker, S. R.; Dober, B.; Egan, D.; Ford, P.; Hilton, G.; Hubmayr, J.; Irwin, K. D.; Marganian, P.; Mason, B. S.; Mates, J. A. B.; McMahon, J.; Mello, M.; Mroczkowski, T.; Romero, C.; Tucker, C.; Vale, L.; White, S.; Whitehead, M.; Young, A. H.

    2016-03-01

    MUSTANG-2 is a 90 GHz feedhorn-coupled, microwave SQUID-multiplexed TES bolometer array in the final stages of development for operation on the 100-m Robert C. Byrd Green Bank Telescope. We present the camera design and report the performance during the first season of observation, in which 64 of the available 215 pixels in the focal plane were populated. We highlight the microwave multiplexing readout technology, which is envisioned as a path to read out the next generation of large pixel-count cryogenic focal planes. In this regard, MUSTANG2 is a pathfinder for this multiplexing technology. We present noise spectra which show no detector noise degradation when read out with microwave SQUID multiplexing, and we present first light images of Jupiter and M87, which demonstrate the end-to-end system performance.

  1. Monolithic HTS microwave phase shifter and other devices

    SciTech Connect

    Jackson, C.M.; Kobayashi, J.H.; Guillory, E.B.; Pettiette-Hall, C.; Burch, J.F. )

    1992-08-01

    We describe a monolithic high-temperature superconductor (HTS) phase shifter based on the distributed Josephson inductance (DJI) design integrated monolithically into a 10-GHz microstrip line. This microwave circuit incorporates >1000 HTS rf SQUIDS. Recent data demonstrate the performance of this broadband HTS circuit. We observed phase shifts greater than 150[degrees] in resonant structures, and 20[degrees] in broadband circuits. The nonlinear inductance of the superconducting transmission line can be used for other novel applications, including parametric amplification. A comparison of the DJI circuit to a series array of Josephson elements (used for pulse sharpening) will contrast these two new and exciting nonlinear transmission line circuits. 19 refs., 4 figs., 2 tabs.

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

    NASA Astrophysics Data System (ADS)

    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.

  3. Frequency multiplexed flux locked loop architecture providing an array of DC SQUIDS having both shared and unshared components

    DOEpatents

    Ganther, Jr., Kenneth R.; Snapp, Lowell D.

    2002-01-01

    Architecture for frequency multiplexing multiple flux locked loops in a system comprising an array of DC SQUID sensors. The architecture involves dividing the traditional flux locked loop into multiple unshared components and a single shared component which, in operation, form a complete flux locked loop relative to each DC SQUID sensor. Each unshared flux locked loop component operates on a different flux modulation frequency. The architecture of the present invention allows a reduction from 2N to N+1 in the number of connections between the cryogenic DC SQUID sensors and their associated room temperature flux locked loops. Furthermore, the 1.times.N architecture of the present invention can be paralleled to form an M.times.N array architecture without increasing the required number of flux modulation frequencies.

  4. Very-low-noise multiplexing with SQUIDs and SiGe HBTs for readout of large superconducting bolometer arrays

    NASA Astrophysics Data System (ADS)

    Prêle, D.; Klisnick, G.; Sou, G.; Redon, M.; Bréelle, E.; Voisin, F.; Piat, M.

    2007-08-01

    We present an ultra-low-noise instrumentation based on a standard BiCMOS SiGe 0.35 μm ASIC operating at cryogenic temperatures. The main functions of the electronic circuit are the readout and the multiplexing of SQUIDs/TES arrays. We report the cryogenic operation of the ASIC dedicated to the readout of a 2×4 pixel demonstrator array. We particularly emphasise on the development, and the test phases of an ultra-low-noise (0.2 nV/√Hz) cryogenic amplifier designed with two multiplexed input. The cryogenic SiGe amplifier coupled to a SQUID in a FLL operating at 4.2 K is also presented.

  5. Very Low Noise Multiplexing with SQUIDs and SiGe Heterojunction Bipolar Transistors for Readout of Large Superconducting Bolometer Arrays

    NASA Astrophysics Data System (ADS)

    Voisin, F.; Bréelle, E.; Piat, M.; Prêle, D.; Klisnick, G.; Sou, G.; Redon, M.

    2008-05-01

    This paper presents an ultra low noise instrumentation based on a standard BiCMOS SiGe 0.35 μm ASIC operating at cryogenic temperatures. The main functions of the electronic circuit are the readout and the multiplexing of SQUIDs/TES. We report the cryogenic operation of the ASIC dedicated to the readout of a 2×4 pixel demonstrator array. We particularly emphasize on the development and the test phases of an ultra low noise ( 0.2 nV/sqrt{Hz} ) cryogenic amplifier designed with two multiplexed inputs. The cryogenic SiGe amplifier coupled to a SQUID in a FLL operating at 4.2 K is also presented.

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

    SciTech Connect

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

    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.

  7. Single SQUID multiplexer for arrays of voltage-biased superconducting bolometers

    SciTech Connect

    Yoon, Jongsoo; Clarke, John; Gildemeister, J.M.; Lee, Adrian T.; Myers, M.J.; Richards, P.L.; Skidmore, J.T.; Spieler, H.G.

    2001-08-20

    We describe a frequency domain superconducting quantum interference device (SQUID) multiplexer which monitors a row of low-temperature sensors simultaneously with a single SQUID. Each sensor is ac biased with a unique frequency and all the sensor currents are added in a superconducting summing loop. A single SQUID measures the current in the summing loop, and the individual signals are lock-in detected after the room temperature SQUID electronics. The current in the summing loop is nulled by feedback to eliminate direct crosstalk. In order to avoid the accumulation of Johnson noise in the summing loop, a tuned bandpass filter is inserted in series with each sensor. For a 32-channel multiplexer for Voltage-biased Superconducting Bolometer (VSB) with a time constant {approx}1msec, we estimate that bias frequencies in the range from {approx}500kHz to {approx}600kHz are practical. The major limitation of our multiplexing scheme is in the slew rate of a readout SQUID. We discuss a ''carrier nulling'' technique which could be used to increase the number of sensors in a row or to multiplex faster bolometers by reducing the required slew rate for a readout SQUID.

  8. First implementation of TES bolometer arrays with SQUID-based multiplexed readout on a balloon-borne platform

    NASA Astrophysics Data System (ADS)

    Aubin, François; Aboobaker, Asad M.; Ade, Peter; Baccigalupi, Carlo; Bao, Chaoyun; Borrill, Julian; Cantalupo, Christopher; Chapman, Daniel; Didier, Joy; Dobbs, Matt; Grainger, Will; Hanany, Shaul; Hubmayr, Johannes; Hyland, Peter; Hillbrand, Seth; Jaffe, Andrew; Johnson, Bradley; Jones, Terry; Kisner, Theodore; Klein, Jeff; Korotkov, Andrei; Leach, Sam; Lee, Adrian; Limon, Michele; MacDermid, Kevin; Matsumura, Tomotake; Meng, Xiaofan; Miller, Amber; Milligan, Michael; Polsgrove, Daniel; Ponthieu, Nicolas; Raach, Kate; Reichborn-Kjennerud, Britt; Sagiv, Ilan; Smecher, Graeme; Tran, Huan; Tucker, Gregory S.; Vinokurov, Yury; Yadav, Amit; Zaldarriaga, Matias; Zilic, Kyle

    2010-07-01

    EBEX (the E and B EXperiment) is a balloon-borne telescope designed to measure the polarisation of the cosmic microwave background radiation. During a two week long duration science flight over Antarctica, EBEX will operate 768, 384 and 280 spider-web transition edge sensor (TES) bolometers at 150, 250 and 410 GHz, respectively. The 10-hour EBEX engineering flight in June 2009 over New Mexico and Arizona provided the first usage of both a large array of TES bolometers and a Superconducting QUantum Interference Device (SQUID) based multiplexed readout in a space-like environment. This successful demonstration increases the technology readiness level of these bolometers and the associated readout system for future space missions. A total of 82, 49 and 82 TES detectors were operated during the engineering flight at 150, 250 and 410 GHz. The sensors were read out with a new SQUID-based digital frequency domain multiplexed readout system that was designed to meet the low power consumption and robust autonomous operation requirements presented by a balloon experiment. Here we describe the system and the remote, automated tuning of the bolometers and SQUIDs. We compare results from tuning at float to ground, and discuss bolometer performance during flight.

  9. Subranging scheme for SQUID sensors

    NASA Technical Reports Server (NTRS)

    Penanen, Konstantin I. (Inventor)

    2008-01-01

    A readout scheme for measuring the output from a SQUID-based sensor-array using an improved subranging architecture that includes multiple resolution channels (such as a coarse resolution channel and a fine resolution channel). The scheme employs a flux sensing circuit with a sensing coil connected in series to multiple input coils, each input coil being coupled to a corresponding SQUID detection circuit having a high-resolution SQUID device with independent linearizing feedback. A two-resolution configuration (course and fine) is illustrated with a primary SQUID detection circuit for generating a fine readout, and a secondary SQUID detection circuit for generating a course readout, both having feedback current coupled to the respective SQUID devices via feedback/modulation coils. The primary and secondary SQUID detection circuits function and derive independent feedback. Thus, the SQUID devices may be monitored independently of each other (and read simultaneously) to dramatically increase slew rates and dynamic range.

  10. SQUIDs: microscopes and nondestructive evaluation

    NASA Astrophysics Data System (ADS)

    Mück, Michael

    2005-03-01

    SQUIDs (Superconducting Quantum Interference Devices) are magnetic field sensores with unsurpassed sensitivity. They are amazingly versatile, being able to measure all physical quantities which can be converted to magnetic flux. They are routinely fabricated in thin film technology from two classes of superconducting materials: high-temperature superconductors (HTS) which are usually cooled to 77 K, and low-temperature superconductors (LTS), which have to be cooled to 4.2 K. SQUIDs have many applications, two of which shall be discussed in this paper. In SQUID microscopy, a SQUID scans a sample, which preferrably is at room temperature, and measures the two-dimensional magnetic field distribution at the surface of the sample. In order to achieve a relatively high spatial resolution, the stand-off distance between the sample and the SQUID is made as small as possible. SQUIDs show also promising results in the field of nondestructive testing of various materials. For example, ferromagnetic impurities in stainless steel formed by aging processes in the material can be detected with high probability, and cracks in conducting materials, for example aircraft parts, can be located using eddy current methods. Especially for the case of thick, highly conductive, or ferromagnetic materials, as well as sintered materials, it can be shown that a SQUID-based NDE system exhibits a much higher sensitivity compared to conventional eddy current NDE and ultrasonic testing.

  11. Time-division SQUID multiplexers

    NASA Astrophysics Data System (ADS)

    Irwin, K. D.; Vale, L. R.; Bergren, N. E.; Deiker, S.; Grossman, E. N.; Hilton, G. C.; Nam, S. W.; Reintsema, C. D.; Rudman, D. A.; Huber, M. E.

    2002-02-01

    SQUID multiplexers make it possible to build arrays of thousands of low-temperature bolometers and microcalorimeters based on superconducting transition-edge sensors with a manageable number of readout channels. We discuss the technical tradeoffs between proposed time-division multiplexer and frequency-division multiplexer schemes and motivate our choice of time division. Our first-generation SQUID multiplexer is now in use in an astronomical instrument. We describe our second-generation SQUID multiplexer, which is based on a new architecture that significantly reduces the dissipation of power at the first stage, allowing thousands of SQUIDs to be operated at the base temperature of a cryostat. .

  12. Low field electron paramagnetic resonance imaging with SQUID detection

    NASA Technical Reports Server (NTRS)

    Hahn, Inseob (Inventor); Day, Peter K. (Inventor); Penanen, Konstantin I. (Inventor); Eom, Byeong H. (Inventor); Cohen, Mark S. (Inventor)

    2012-01-01

    In one embodiment, a flux transformer with a gradiometer pickup coil is magnetically coupled to a SQUID, and a SQUID array amplifier comprising a plurality of SQUIDs, connected in series, is magnetically coupled to the output of the SQUID. Other embodiments are described and claimed.

  13. Progress towards a double flux-locked-loop scheme for SQuID readout of TES detector arrays

    NASA Astrophysics Data System (ADS)

    Torrioli, Guido; Lombardo, Simona; Macculi, Claudio; Piro, Luigi; Colasanti, Luca

    2014-07-01

    Frequency Division Multiplexing technique for reading TES detectors with SQuID devices, requires high loop-gain up to MHz frequency range in the SQuID feedback loop. Such a requirement is difficult to achieve when the feedback loop has a physical length that makes the propagation times of signals not negligible, as in the case in which the readout electronics is placed at room temperature. A novel SQuID readout scheme, called Double Loop-Flux Locked loop (DLFLL), has been proposed earlier. According to this scheme it is possible to make use of a simplified cryogenic electronics, AC coupled, featuring low power dissipation, in order to obtain a cryogenic feedback loop that results in reduced propagation times of signals. The DC and low frequency signals are managed by a standard FLL electronics working at room temperature. Here we present the progress of the integrated Double Loop system.

  14. An X-band SQUID Multiplexer

    NASA Astrophysics Data System (ADS)

    Hahn, I.; Bumble, B.; LeDuc, H. G.; Weilert, M.; Day, P.

    2006-09-01

    We are developing a microwave readout multiplexer for arrays of superconducting quantum interference devices (SQUIDs). A series of microwave resonators with frequencies ˜10 GHz are each loaded by a dc SQUID to a degree that depends on the flux state of the SQUID. By using resonators with high quality factors and slightly different resonance frequencies, many of these resonator-coupled SQUIDs may be read out with a single excitation line and cryogenic amplifier. Our multiplexer is similar to the one demonstrated by Irwin and Lehnert except for the use of higher-frequency, fully-lithographed transmission line resonators. We discuss a technique for modulating the SQUID array in series that alleviates the need to individually flux-bias the SQUIDs. The multiplexer has applications to the readout of detector arrays for astronomy as well as medical magnetic imaging.

  15. A Double Flux Locked Loop Scheme For SQUID Readout Of TES Detector Arrays Using The FDM Technique

    NASA Astrophysics Data System (ADS)

    Torrioli, G.; Bastia, P.; Piro, L.; Macculi, C.; Colasanti, L.

    2009-12-01

    SQUIDs readout electronics for TES microcalorimeters are generally based on the standard Flux Locked Loop scheme in which the SQUID is inserted in a feedback circuit in order to increase its Dynamic Range. For those applications in which a high loop gain at high frequency is needed, such as FDM multiplexing of a large number of pixels, the distance between the SQUID and room temperature electronics limits the performances due to the finite propagation time of the signal. Here we present a solution in which the feedback electronics is located in the cryogenic environment as close as possible to the SQUID. In particular we adopt a scheme in which the feedback loop is split in two paths: a high frequency FLL loop in cryogenic environment and a low frequency loop which is closed at room temperature. With this approach it is not necessary to have a precision DC amplifier working at cryogenic temperatures, resulting in a substantial simplification of the cryogenic components of the electronics. This paper describes the theory behind and the experimental work which is currently carried out to prove this concept.

  16. The Microwave SQUID Multiplexer

    NASA Astrophysics Data System (ADS)

    Mates, John Arthur Benson

    2011-12-01

    This thesis describes a multiplexer of Superconducting Quantum Interference Devices (SQUIDs) with low-noise, ultra-low power dissipation, and great scalability. The multiplexer circuit measures the magnetic flux in a large number of unshunted rf SQUIDs by coupling each SQUID to a superconducting microwave resonator tuned to a unique resonance frequency and driving the resonators from a common feedline. A superposition of microwave tones measures each SQUID simultaneously using only two coaxial cables between the cryogenic device and room temperature. This multiplexer will enable the instrumentation of arrays with hundreds of thousands of low-temperature detectors for new applications in cosmology, materials analysis, and nuclear non-proliferation. The driving application of the Microwave SQUID Multiplexer is the readout of large arrays of superconducting transition-edge sensors, by some figures of merit the most sensitive detectors of electromagnetic signals over a span of more than nine orders of magnitude in energy, from 40 GHz microwaves to 200 keV gamma rays. Modern transition-edge sensors have noise-equivalent power as low as 10-20 W / Hz1/2 and energy resolution as good as 2 eV at 6 keV. These per-pixel sensitivities approach theoretical limits set by the underlying signals, motivating a rapid increase in pixel count to access new science. Compelling applications, like the non-destructive assay of nuclear material for treaty verification or the search for primordial gravity waves from inflation use arrays of these detectors to increase collection area or tile a focal plane. We developed three generations of SQUID multiplexers, optimizing the first for flux noise 0.17 muPhi0 / Hz1/2, the second for input current noise 19 pA / Hz1/2, and the last for practical multiplexing of large arrays of cosmic microwave background polarimeters based on transition-edge sensors. Using the last design we demonstrated multiplexed readout of prototype polarimeters with the

  17. YBa2Cu3O7-delta dc SQUID array for multichannel magnetometry and multichannel flip-chip current sensors

    NASA Astrophysics Data System (ADS)

    Ramos, J.; Zakosarenko, V.; IJsselsteijn, R.; Stolz, R.; Schultze, V.; Chwala, A.; Hoenig, H. E.; Meyer, H.-G.

    1999-09-01

    We have prepared arrays of single-layer washer-type dc superconducting quantum interference devices (SQUIDs) on 10 mm × 10 mm bicrystal substrates. Each SQUID in the array is equipped with its own modulation loop, which makes a separate operation of them possible. Arrays containing nine or 11 dc SQUIDs have been tested and the crosstalk between neighbouring channels has been found to be 5%. The field sensitivity of the SQUIDs is 85 nT icons/Journals/Common/Phi" ALT="Phi" ALIGN="TOP"/>0-1 and 105 nT icons/Journals/Common/Phi" ALT="Phi" ALIGN="TOP"/>0-1 for the nine- and 11-device array, respectively. The equivalent flux noise is typically icons/Journals/Common/le" ALT="le" ALIGN="TOP"/> 20 icons/Journals/Common/mu" ALT="mu" ALIGN="TOP"/>icons/Journals/Common/Phi" ALT="Phi" ALIGN="TOP"/>0 Hz-1/2 down to 1 Hz with ac bias reversal. A field resolution of less than 2.1 pT Hz-1/2 has been obtained for at least eight channels on a chip. By using multiturn YBa2Cu3O7-icons/Journals/Common/delta" ALT="delta" ALIGN="MIDDLE"/> input coils and mounting them in a flip-chip configuration together with the single-layer dc SQUIDs we have been able to build three-channel current sensors. The current sensitivity equals 3-3.5 icons/Journals/Common/mu" ALT="mu" ALIGN="TOP"/>A icons/Journals/Common/Phi" ALT="Phi" ALIGN="TOP"/>0-1 depending on the alignment of the flip-chip configuration. The current resolution of the devices is < 70 pA Hz-1/2. We show the possibility of building sensitive magnetometers by connecting the input coil of these current sensors to a normal-conducting pickup antenna.

  18. TOPICAL REVIEW: SQUID systems for biomagnetic imaging

    NASA Astrophysics Data System (ADS)

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

    2001-07-01

    This review paper illustrates the different SQUID based systems used for biomagnetic imaging. The review is divided into nine sections. The first three sections are introductory: section 1 is a short overview of the topic; section 2 summarizes how the biomagnetic fields are generated and what are the basic mathematical models for the field sources; section 3 illustrates the principles of operation of the SQUID device. Sections 4-8 are specifically devoted to the description of the different systems used for biomagnetic measurements: section 4 discusses the different types of detection coils; section 5 illustrates the SQUID sensors specifically designed for biomagnetic applications together with the necessary driving electronics, with special emphasis on high-temperature superconductivity (HTS) SQUIDs, since HTS devices are still in a developing stage; section 6 illustrates the different noise reduction techniques; section 7 describes the different multichannel sensors presently operating; and, finally, section 8 gives a hint of what kind of physiological and/or clinical information may be gathered by the biomagnetic technique. Section 9 suggests some future trends for the biomagnetic technique.

  19. Use of a SQUID array to detect T-cells with magnetic nanoparticles in determining transplant rejection

    NASA Astrophysics Data System (ADS)

    Flynn, Edward R.; Bryant, H. C.; Bergemann, Christian; Larson, Richard S.; Lovato, Debbie; Sergatskov, Dmitri A.

    2007-04-01

    Acute rejection in organ transplant is signaled by the proliferation of T-cells that target and kill the donor cells requiring painful biopsies to detect rejection onset. An alternative non-invasive technique is proposed using a multi-channel superconducting quantum interference device (SQUID) magnetometer to detect T-cell lymphocytes in the transplanted organ labeled with magnetic nanoparticles conjugated to antibodies specifically attached to lymphocytic ligand receptors. After a magnetic field pulse, the T-cells produce a decaying magnetic signal with a characteristic time of the order of a second. The extreme sensitivity of this technique, 10 5 cells, can provide early warning of impending transplant rejection and monitor immune-suppressive chemotherapy.

  20. Coupled Serial and Parallel Non-uniform SQUIDs

    SciTech Connect

    Longhini, Patrick; In, Visarath; Berggren, Susan; Palacios, Antonio; Leese de Escobar, Anna

    2011-04-19

    In this work we numerical model series and parallel non-uniform superconducting quantum interference device (SQUID) array. Previous work has shown that series SQUID array constructed with a random distribution of loop sizes, (i.e. different areas for each SQUID loop) there exists a unique 'anti-peak' at the zero magnetic field for the voltage versus applied magnetic field (V-B). Similar results extend to a parallel SQUID array where the difference lies in the arrangement of the Josephson junctions. Other system parameter such as bias current, the number of loops, and mutual inductances are varied to demonstrate the change in dynamic range and linearity of the V-B response. Application of the SQUID array as a low noise amplifier (LNA) would increase link margins and affect the entire communication system. For unmanned aerial vehicles (UAVs), size, weight and power are limited, the SQUID array would allow use of practical 'electrically small' antennas that provide acceptable gain.

  1. Reflective HTS switch

    DOEpatents

    Martens, Jon S.; Hietala, Vincent M.; Hohenwarter, Gert K. G.

    1994-01-01

    A HTS switch includes a HTS conductor for providing a superconducting path for an electrical signal and an serpentine wire actuator for controllably heating a portion of the conductor sufficiently to cause that portion to have normal, and not superconducting, resistivity. Mass of the portion is reduced to decrease switching time.

  2. Reflective HTS switch

    DOEpatents

    Martens, J.S.; Hietala, V.M.; Hohenwarter, G.K.G.

    1994-09-27

    A HTS (High Temperature Superconductor) switch includes a HTS conductor for providing a superconducting path for an electrical signal and an serpentine wire actuator for controllably heating a portion of the conductor sufficiently to cause that portion to have normal, and not superconducting, resistivity. Mass of the portion is reduced to decrease switching time. 6 figs.

  3. Recent developments in SQUID NDE

    NASA Astrophysics Data System (ADS)

    Krause, H.-J.; Kreutzbruck, M. v.

    2002-03-01

    By presenting brief summaries of recent application highlights, an overview of NDE methods using SQUIDs is given. Bridge inspection with a SQUID array integrated with a yoke magnet excitation was shown by scanning along the pre-stressed steel of bridges and verified by opening the bridge deck. As the construction of the megaliner Airbus aircraft progresses, testing procedures for extremely thick-walled structures are needed. Defects at a depth of up to 40 mm were measured in a bolted three-layer aluminum sample with a total thickness of 62 mm. For the investigation of aircraft wheels, a remote eddy current (EC) excitation scheme yields better depth selectivity. Defects with an inside penetration of only 10% could be detected. SQUID magnetometers are well suited for pulsed EC techniques which cover a broader depth range than standard single frequency EC. An inversion procedure is presented providing a tomographic-like conductivity image of stacked aluminum samples. A recent SQUID application is nondestructive testing of niobium sheets used for superconducting cavities of particle accelerators. The detection of tantalum inclusions and other impurities which lower the cavity performance is based on the measurement of local current inhomogeneities caused by EC excitation or thermal gradients. Alternate techniques using SQUID sensors, such as modulated excitation arrays, rotating field schemes, sensor multiplexing, magnetic moment detection, and microscopy setups, are discussed.

  4. High-temperature single-layer SQUID gradiometers with long baseline and parasitic effective area compensation

    NASA Astrophysics Data System (ADS)

    Pegrum, C. M.; Eulenburg, A.; Romans, E. J.; Carr, C.; Millar, A. J.; Donaldson, G. B.

    1999-11-01

    First-order HTS SQUID gradiometers were fabricated on 30 × 10 mm2 bicrystal substrates. These devices have a baseline of 13 mm, intrinsic balance levels of ~1/700 and a typical gradient sensitivity at 1 kHz of 79 fT cm-1 Hz-1/2. A two-SQUID coupling scheme is discussed that further enhances the device's ability to reject uniform fields.

  5. Application of shielding current in bulk HTS to control magnetic field distribution

    NASA Astrophysics Data System (ADS)

    Kii, T.

    2016-03-01

    Superconducting shielding current is excited when external field is applied to superconductor. In case for field cooling of bulk superconductor, shielding current is an origin of strong trapped field. When external field is changed to a properly arranged bulk HTS array, various magnetic field distribution can be formed by an excited shielding current in each bulk HTS. This paper presents a simple intuitively method to design magnetic field distribution using supercurrents in bulk high-temperature superconductor (HTS) array. In this method, an ideal current path for intended field distribution is represented by shielding currents in bulk HTS array. Expected performance can be roughly estimated by using Biot-Savart law. As examples, Maxwell coil pair and helical field generator are designed. This method can be applied to design various magnet devices using bulk HTS array.

  6. The Squid Challenge.

    ERIC Educational Resources Information Center

    Guillaume, Andrea M.

    1997-01-01

    Describes an approach to the study of squid that helps students of all ages develop richer ideas about the structure of living things, how living things are adapted to their habitats, and how they interact with other organisms. Highlights include the external and internal features of the squid, squid statements and statistics, and writing…

  7. High-Tc and low-Tc dc SQUID electronics

    NASA Astrophysics Data System (ADS)

    Drung, Dietmar

    2003-12-01

    Superconducting quantum interference devices (SQUIDs) are commonly operated in a flux-locked loop (FLL). The SQUID electronics amplifies the small SQUID signal to an acceptable level without adding noise, and it linearizes the transfer function of the SQUID in order to provide sufficient dynamic range. In this paper, the fundamentals of SQUID readout are reviewed including a discussion of preamplifier noise. The basic FLL concepts, direct readout and flux modulation readout, are discussed both with dc bias and bias reversal. Alternative readout concepts such as additional positive feedback (APF), two-stage SQUIDs, SQUID series arrays, relaxation oscillation SQUIDs and digital SQUIDs are briefly described. The FLL dynamics are discussed on the basis of a simple model with finite loop delay. It is shown that with optimized SQUID electronics a system bandwidth of ap18 MHz and a corresponding slew rate of ap8 PHgr0 µs-1 are possible. A novel FLL scheme involving a Smith predictor is presented which allows one to increase the FLL bandwidth to about 100 MHz. The theoretical predictions are experimentally checked using a high-speed SQUID electronics prototype with a small-signal bandwidth of 300 MHz. Methods for increasing the dynamic range of SQUID systems are described: flux-quanta counting and dynamic field compensation (DFC). With DFC, the residual magnetic field at the SQUID can be kept close to zero even if the device is moved in the Earth's field. Therefore, the noise level of a high-Tc magnetometer measured inside a magnetically shielded room (60 fT Hz-1/2 with a 1/f corner at 2 Hz) remained unchanged after moving the device in the magnetic field outside the room (60 µT dc plus 0.8 µT peak-to-peak power line interference).

  8. The set-up of a high temperature superconductor radio-frequency SQUID microscope for magnetic nanoparticle detection

    NASA Astrophysics Data System (ADS)

    Schmidt, M.; Krause, H.-J.; Banzet, M.; Lomparski, D.; Schubert, J.; Zander, W.; Zhang, Y.; Akram, R.; Fardmanesh, M.

    2006-05-01

    SQUID (superconducting quantum interference device) microscopes are versatile instruments for biosensing applications, in particular for magnetic nanoparticle detection in immunoassay experiments. We are developing a SQUID microscope based on an HTS rf SQUID magnetometer sensor with a substrate resonator. For the cryogenic set-up, a configuration was realized in which the cryostat is continuously refilled and kept at a constant liquid nitrogen level by an isolated tube connection to a large liquid nitrogen reservoir. The SQUID is mounted on top of a sapphire finger, connected to the inner vessel of the stainless steel cryostat. The vacuum gap between the cold SQUID and room temperature sample is adjusted by the precise approach of a 50 µm thin sapphire window using a single fine thread wheel. We investigated possible sensing tip configurations and different sensor integration techniques in order to achieve an optimized design. A new scheme of coupling the rf SQUID from its back to a SrTiO3 substrate resonator was adopted for the purpose of minimization of the sensor-to-sample spacing. By SQUID substrate thinning and washer size reduction, the optimum coupling conditions for back coupling were determined for different rf SQUID magnetometers prepared on LaAlO3 and SrTiO3 substrates. The SQUID microscope system is characterized with respect to its spatial resolution and its magnetic field noise. The SQUID microscope instrument will be used for magnetic nanoparticle marker detection.

  9. An HTS Machine Laboratory Prototype

    NASA Astrophysics Data System (ADS)

    Mijatovic, N.; Jensen, B. B.; Træholta, C.; Abrahamsen, A. B.; Zermeno, V. M. R.; Pedersen, N. F.

    This paper describes Superwind HTS machine laboratory setup which is a small scale HTS machine designed and build as a part of the efforts to identify and tackle some of the challenges the HTS machine design may face. One of the challenges of HTS machines is a Torque Transfer Element (TTE) which is in this design integral part of the cryostat. The discussion of the requirements for the TTE supported with a simple case study comparing a shaft and a cylinder as candidates for TTE are presented. The discussion resulted with a cylinder as a TTE design rated for a 250Nm and with more then 10 times lower heat conduction compared to a shaft. The HTS machine was successfully cooled to 77K and tests have been performed. The IV curves of the HTS field winding employing 6 HTS coils indicate that two of the coils had been damaged. The maximal value of the torque during experiments of 78Nm was recorded. Loaded with 33%, the TTE performed well and showed suffcient margin for future experiments.

  10. Calibration of a HTS Based LOX 400 mm Level Sensor

    NASA Astrophysics Data System (ADS)

    Karunanithi, R.; Jacob, S.; Nadig, D. S.; Prasad, M. V. N.; Gour, Abhay S.; Pankaj, S.; Gowthaman, M.; Sudharshan, H.

    The measurement of the cryogen level in a cryostage of space crafts is crucial. At the same time the weight of the sensor should be small as it affects the payload fraction of the space craft. An attempt to develop a HTS based level sensor of 400 mm for Liquid Oxygen (LOX) measurement was made. In the initial phase of testing, loss of superconductivity of HTS wire in LOX inside a cryostat was noticed. Thus, a new four wall cryostat was designed to have a stable LOX level to provide thermal stability to the HTS based LOX sensor. The calibration of the developed sensor was carried out against capacitance level sensor which was pre calibrated using diode array to verify its linearity and performance for different current excitation levels. The calibrations were carried out without heater wires. The automatic data logging was accomplished using a program developed in LabVIEW 11.0.

  11. Development of Ultra-low Field SQUID-MRI System with an LC Resonator

    NASA Astrophysics Data System (ADS)

    Yamamoto, M.; Toyota, H.; Kawagoe, S.; Hatta, J.; Tanaka, S.

    We are developing an Ultra-Low Field (ULF) magnetic resonance imaging (MRI) system using high temperature superconductor (HTS)-rf-superconducting quantum interference device (SQUID) for food inspection. The advantage of the ULF MRI system is that non-magnetic contaminants, which are difficult to be detected by a magnetic sensor, can be detected and localized. The system uses HTS-SQUID with high sensitivity that is independent of frequency, because the signal frequency is reduced in ULF. However the detection area of HTS-SQUID is difficult to be increased. Therefore, we studied to increase the detection area using an LC resonator. The LC resonator is composed of a coil (22.9 mH, Φ40 mm inner diameter) and a capacitor (the setting resonance frequency of 1890 Hz). The signal is detected by a copper wound coil of the resonator, and transferred to HTS-SQUID that inductively coupled to the coil immersed in liquid nitrogen at 77 K. We combined the LC resonator with the ULF MRI system, and obtained the 2D-MR images. The signal detector, with the SQUID and the LC resonator, provided a 1.5 times larger detection area. The size of 2D-MR image was near the size of the actual sample. Then we obtained 2D-MR images by a filtered back projection (FBP) method and a 2D-fast fourier transform (FFT) method. In the 2D-FFT method, the pixel size of the image was smaller than that of image by FBP method. As a result, the quality of the 2D-MR image by 2D-FFT method has been improved. There results suggested that the system we are proposing is feasible.

  12. Non-destructive testing (NDT) of metal cracks using a high Tc rf-SQUID and eddy current method

    SciTech Connect

    Lu, D.F.; Fan, C.; Ruan, J.Z.

    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. Non-destructive Testing (NDT) of metal cracks using a high Tc rf-SQUID and eddy current method

    NASA Technical Reports Server (NTRS)

    Lu, D. F.; Fan, Chang-Xin; Ruan, J. Z.; Han, S. G.; Wong, K. W.; Sun, G. F.

    1995-01-01

    A SQUID is the most sensitive device to detect change in magnetic field. A nondestructive testing (NDT) device using high temperature SQUID's and eddy current method will be much more sensitive than those currently used eddy current systems, yet much cheaper than one with low temperature SQUID's. 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.

  14. Optical fiber feedback SQUID magnetometer

    SciTech Connect

    Naito, S.; Sampei, Y.; Takahashi, T. )

    1989-04-01

    This paper describes an optical fiber feedback superconducting quantum interference device (SQUID) magnetometer which was developed to improve electromagnetic interference characteristics. The SQUID consists of an RF SQUID probe, an RF amplifier, two multimode fibers, and a SQUID control unit. Phase-locked pulse width modulation (PWM) was used to construct a flux locked loop (FLL) circuit in the SQUID control unit. The operation of the optical fiber feedback SQUID is stable when a common mode voltage of ac 100 V/50 Hz is applied. It has an energy resolution of 1 x 10/sup -28/ J/Hz. This paper also describes the measurement of an auditory evoked field from the human brain in a magnetically shielded room using the fiber feedback SQUID with a gradiometer type pickup coil.

  15. SQUIDs - ultimate magnetic sensors

    NASA Astrophysics Data System (ADS)

    Donaldson, Gordon B.

    2005-03-01

    SQUIDs (Superconducting Quantum Interference Devices) have extreme electromagnetic energy sensitivity, which can be applied in a wide variety of ways. Some of these are covered in the papers representing the rest of this symposium: in this brief introductory paper we indicate the wide extent of the full range of applications to which they have been put, from bioscience to tests of General Relativity.

  16. Low-noise SQUID

    DOEpatents

    Dantsker, Eugene; Clarke, John

    2000-01-01

    The present invention comprises a high-transition-temperature superconducting device having low-magnitude low-frequency noise-characteristics in magnetic fields comprising superconducting films wherein the films have a width that is less than or equal to a critical width, w.sub.C, which depends on an ambient magnetic field. For operation in the Earth's magnetic field, the critical width is about 6 micrometers (.mu.m). When made with film widths of about 4 .mu.m an inventive high transition-temperature, superconducting quantum interference device (SQUID) excluded magnetic flux vortices up to a threshold ambient magnetic field of about 100 microTesla (.mu.T). SQUIDs were fabricated having several different film strip patterns. When the film strip width was kept at about 4 .mu.m, the SQUIDs exhibited essentially no increase in low-frequency noise, even when cooled in static magnetic fields of magnitude up to 100 .mu.T. Furthermore, the mutual inductance between the inventive devices and a seven-turn spiral coil was at least 85% of that for inductive coupling to a conventional SQUID.

  17. Geophysical applications of squids

    SciTech Connect

    Clarke, J.

    1983-05-01

    Present and potential geophysical applications of Superconducting Quantum Interference Devices (SQUIDs) include remote reference magnetotellurics, controlledsource electromagnetic sounding, airborne gradiometry, gravity gradiometers, rock magnetism, paleomagnetism, piezomagnetism, tectonomagnetism, the location of hydrofractures for hot dry rock geothermal energy and enhanced oil and gas recovery, the detection of internal ocean waves, and underwater magnetotellurics.

  18. Low-noise SQUID

    SciTech Connect

    Dantsker, E.; Clarke, J.

    2000-02-08

    The present invention comprises a high-transition-temperature superconducting device having low-magnitude low-frequency noise-characteristics in magnetic fields comprising superconducting films wherein the films have a width that is less than or equal to a critical width, w(C), which depends on an ambient magnetic field. For operation in the Earth's magnetic field, the critical width is about 6 micrometers ({mu}m). When made with film widths of about 4 {mu}m an inventive high transition-temperature, superconducting quantum interference device (SQUID) excluded magnetic flux vortices up to a threshold ambient magnetic field of about 100 microTesla ({mu}T). SQUIDs were fabricated having several different film strip patterns. When the film strip width was kept at about 4 {mu}m, the SQUIDs exhibited essentially no increase in low-frequency noise, even when cooled in static magnetic fields of magnitude up to 100 {mu}T. Furthermore, the mutual inductance between the inventive devices and a seven-turn spiral coil was at least 85% of that for inductive coupling to a conventional SQUID.

  19. SQUIDs: Then and Now

    NASA Astrophysics Data System (ADS)

    Clarke, John

    2014-03-01

    In 1964, Jaklevic, Lambe, Silver and Mercereau demonstrated quantum interference in a superconducting ring containing two Josephson tunnel junctions. This observation marked the birth of the SQUID--Superconducting QUantum Interference Device. The following year saw the appearance of the SLUG (Superconducting Low-inductance Undulatory Galvanometer)--a blob of solder frozen around a length of niobium wire--that was used as a voltmeter with femtovolt resolution. Although extremely primitive by today's standards, the SLUG was used successfully in a number of ultrasensitive experiments. Today, the square washer dc SQUID, fabricated on a wafer-scale from thin films with an integrated input coil, finds a wide range of applications. One example is the use of a SQUID amplifier to read out ADMX--Axion Dark Matter eXperiment--at the University of Washington, Seattle. This experiment, which involves a cooled microwave cavity surrounded by a superconducting magnet, searches for the axion, a candidate for cold dark matter. In the presence of a magnetic field the axion is predicted to decay into a photon, which is detected by the SQUID. In another example, the combination of a SQUID with prepolarized proton spins enables one to perform magnetic resonance imaging (MRI) in magnetic fields of the order of 0.1 mT, four orders of magnitude lower than in conventional MRI systems. In vivo images of the human brain acquired at these ultralow fields are able distinguish brain tissue, blood, cerebrospinal fluid and scalp fat using a combination of inversion recovery and multiple echo sequences. Potential clinical applications are briefly discussed.

  20. Dissect Your Squid and Eat It Too!

    ERIC Educational Resources Information Center

    McGinnis, Patricia

    2001-01-01

    Introduces a science lab activity in which students dissect fresh squids in groups of four and observe the anatomy. Parent volunteers cook the squid mantle for kids to taste. Includes directions for squid dissection. (YDS)

  1. SQUID With Integral Flux Concentrator

    NASA Technical Reports Server (NTRS)

    Peters, Palmer N.; Sisk, Robert C.

    1989-01-01

    In improved superconducting quantum interference device (SQUID), change in size and shape of superconducting ring improves coupling to external signal coil and eases coil-positioning tolerances. More rugged and easier to manufacture than conventional SQUID's with comparable electrical characteristics. Thin-film superconducting flux concentrator utilizes Meissner effect to deflect magnetic field of signal coil into central hole of SQUID. Used in magnetometers, ammeters, analog-to-digital converters, and related electronic applications in which high signal-to-noise ratios required.

  2. HTS High Gradient Magnetic Separation system

    SciTech Connect

    Daugherty, M.A.; Coulter, J.Y.; Hults, W.L.

    1996-09-01

    We report on the assembly, characterization and operation of a high temperature superconducting (HTS) magnetic separator. The magnet is made of 624 m of Silver/BSCCO superconducting wire and has overall dimensions of 18 cm OD, 15.5 cm height and 5 cm ID. The HTS current leads are designed to operate with the warm end at 75 K and the cold end cooled by a two stage Gifford-McMahon cryocooler. The upper stage of the cryocooler cools the thermal shield and two heat pipe thermal intercepts. The lower stage of the cryocooler cools the HTS magnet and the bottom end of the HTS current leads. The HTS magnet was initially characterized in liquid cryogens. We report on the current- voltage (I-V) characteristics of the HTS magnet at temperatures ranging from 15 to 40 K. At 40 K the magnet can generate a central field of 2.0 T at a current of 120 A.

  3. Characteristics of the magnetic field distribution on compact NMR magnets using cryocooled HTS bulks

    NASA Astrophysics Data System (ADS)

    Kim, S. B.; Takano, R.; Nakano, T.; Imai, M.; Hahn, S. Y.

    2009-10-01

    Recently, the performance of high temperature superconducting (HTS) bulks such as critical current density, size, and mechanical strength has been improved rapidly. So, various applications using HTS bulks such as motors, bearings and flywheels have been investigated by many research groups. A compact nuclear magnetic resonance (NMR) magnet is one of the new applications after a technique to enhance maximum trapped field of the HTS bulk more than 11.7 T (500 MHz 1H NMR frequency) has been developed. This new compact NMR magnet out of HTS bulks is cost-effective compared with conventional NMR magnets and then expected to be widely used in food and drug industry. In design and manufacture of the compact NMR magnets, spatial field homogeneity of the large trapped magnetic field in HTS bulk annuli is a crucial issue because the behavior of a trapped field is highly non-linear and, as a result, a technique to improve the field homogeneity such as active/passive shimming now becomes more challenging compared with that of the conventional counterparts. This paper presents the magnetic field distributions in single and three assembled HTS bulk annuli measured by a 3-axis and multi-arrayed Hall sensor under two different cryogenic environments: (1) in a bath of liquid nitrogen (LN 2) and (2) dry cooling by a cryocooler. The spatial homogeneity changes with various operating temperatures were investigated and the effect of critical current density enhancement by lowering the operating temperature on the field homogeneity improvement was discussed in detail.

  4. Enhanced Dynamic Range in N-SQUID Lumped Josephson Parametric Amplifiers

    NASA Astrophysics Data System (ADS)

    Eddins, A.; Levenson-Falk, E. M.; Toyli, D. M.; Vijay, R.; Minev, Z.; Siddiqi, I.

    2014-03-01

    Simultaneously providing high gain and nearly quantum-limited noise performance, superconducting parametric amplifiers (paramps) have been used successfully for high fidelity qubit readout, quantum feedback, and microwave quantum optics experiments. The Lumped Josephson Parametric Amplifier (LJPA) consists of a capacitively shunted SQUID coupled to a transmission line to form a nonlinear resonator. Like other paramps employing a resonant circuit, the LJPA's dynamic range-a potentially key ingredient for multiplexing-is limited. Simple theory predicts that the dynamic range can be increased without any reduction in bandwidth or gain by distributing the resonator nonlinearity over a series array of SQUIDs. We fabricated such array devices with up to 5 SQUIDs and observed a clear increase in the critical power for bifurcation about which parametric gain occurs. We discuss in detail amplifier performance as a function of the number of SQUIDs in the array. This research was supported by the Army Research Office under a QCT grant.

  5. Metallic Magnetic Calorimeters with On-Chip dc-SQUID Readout

    NASA Astrophysics Data System (ADS)

    Kempf, S.; Ferring, A.; Fleischmann, A.; Wegner, M.; Enss, C.

    2016-07-01

    Metallic magnetic calorimeters (MMCs) are low-temperature particle detectors that are typically read out by using superconducting quantum interference devices (SQUIDs). But since MMCs are sensitive to the input circuitry and the noise performance of the SQUID, the energy resolution of MMCs have not yet reached their fundamental limit. A possible solution to overcome present limits is to maximize the flux coupling by minimizing parasitic inductance in the input circuit. To show the suitability of this approach, we realized a 64 pixel MMC detector array with integrated dc-SQUID readout, i.e., detector and SQUID are on the same chip. We observed an influence of the power dissipation of the SQUID on the detector temperature. We achieved a baseline energy resolution of Δ E_mathrm {FWHM} = 25 mathrm {eV} and Δ E_mathrm {FWHM} = 30 mathrm {eV} for X-rays with energies up to 6 mathrm {keV}.

  6. Metallic Magnetic Calorimeters with On-Chip dc-SQUID Readout

    NASA Astrophysics Data System (ADS)

    Kempf, S.; Ferring, A.; Fleischmann, A.; Wegner, M.; Enss, C.

    2016-07-01

    Metallic magnetic calorimeters (MMCs) are low-temperature particle detectors that are typically read out by using superconducting quantum interference devices (SQUIDs). But since MMCs are sensitive to the input circuitry and the noise performance of the SQUID, the energy resolution of MMCs have not yet reached their fundamental limit. A possible solution to overcome present limits is to maximize the flux coupling by minimizing parasitic inductance in the input circuit. To show the suitability of this approach, we realized a 64 pixel MMC detector array with integrated dc-SQUID readout, i.e., detector and SQUID are on the same chip. We observed an influence of the power dissipation of the SQUID on the detector temperature. We achieved a baseline energy resolution of Δ E_{FWHM} = 25 {eV} and Δ E_{FWHM} = 30 {eV} for X-rays with energies up to 6 {keV}.

  7. Cryogenic Integrated Offset Compensation for Time Domain SQUID Multiplexing

    NASA Astrophysics Data System (ADS)

    Prêle, D.; Voisin, F.; Martino, J.; Bréelle, E.; Bordier, G.; Piat, M.

    2012-06-01

    Superconducting QUantum Interference Device (SQUID) multiplexing is a common technique in the use of large arrays of Transition Edge Sensors (TES). A Time Domain Multiplexer (TDM) combines input TES signals into one output signal using several SQUIDs. Different TES, SQUID and amplifier characteristics induce unavoidable different offsets on the multiplexed signal. Additionally, given the periodicity of the SQUID characteristic, the Flux Locked Loop (FLL) operating point is only defined modulo Φ 0. This can lead to a large output offset. In multiplexed mode, the difference between offsets associated with different pixels can induce a parasitic signal which is often larger than that of the TES. These offset signals drastically constrain the readout dynamic range and thus the maximum gain allowed. They also limit the signal-to-noise ratio, the FLL stability and the multiplexing frequency. Offsets in SQUID readout are discussed and offset compensation for TDM is presented. The dynamic calibration and compensation on a simplified 4:1 TDM are demonstrated in simulation. Dynamic offset compensation is being implemented on a cryogenic SiGe integrated circuit operated at 4 K for 128:1 TDM.

  8. A SQUID-based metal detector—comparison to coil and x-ray systems

    NASA Astrophysics Data System (ADS)

    Bick, M.; Sullivan, P.; Tilbrook, D. L.; Du, J.; Gnanarajan, S.; Leslie, K. E.; Foley, C. P.

    2005-03-01

    The presence of foreign metal bodies and fragments in foodstuff and pharmaceutical products is of major concern to producers. Further, hidden metal objects can pose threats to security. In particular, stainless steel is difficult to detect by conventional coil metal detectors due to its low conductivity. We have employed an HTS SQUID magnetometer for the detection of stainless steel particles which is based on the measurement of the remanent magnetization of the particle. Our aim was to determine the detection limits of HTS SQUID-based remote magnetometry, especially for food inspection purposes, and to make a comparison of this technique to commonly used eddy current coil and x-ray inspection systems. We show that the SQUID system's sensitivity to stainless steel fragments is significantly higher than that of coil systems if the samples are magnetized in a 100 mT magnetic field prior to detection. Further, it has a higher sensitivity than x-ray systems, depending on the density distribution of the product under inspection. A 0.6 mg piece of grade-316 stainless steel (a fragment of a hypodermic needle 0.5 mm long and 0.65 mm diameter) represents the detection limit of our system with a 150 × 150 mm2 inspection orifice.

  9. A 128 Multiplexing Factor Time-Domain SQUID Multiplexer

    NASA Astrophysics Data System (ADS)

    Prêle, D.; Voisin, F.; Piat, M.; Decourcelle, T.; Perbost, C.; Chapron, C.; Rambaud, D.; Maestre, S.; Marty, W.; Montier, L.

    2016-07-01

    A cryogenic 128:1 Time-Domain Multiplexer (TDM) has been developed for the readout of kilo-pixel Transition Edge Sensor (TES) arrays dedicated to the Q&U Bolometric Interferometer for Cosmology (QUBIC) instrument which aims to measure the B-mode polarization of the Cosmic Microwave Background. Superconducting QUantum Interference Devices (SQUIDs) are usually used to read out TESs. Moreover, SQUIDs are used to build TDM by biasing sequentially the SQUIDs connected together—one for each TES. In addition to this common technique which allows a typical 32 multiplexing factor, a cryogenic integrated circuit provides a 4:1 second multiplexing stage. This cryogenic integrated circuit is one of the original part of our TDM achieving an unprecedented 128 multiplexing factor. We present these two dimension TDM stages: topology of the SQUID multiplexer, operation of the cryogenic integrated circuit, and integration of the full system to read out a TES array dedicated to the QUBIC instrument. Flux-locked loop operation in multiplexed mode is also discussed.

  10. A 128 Multiplexing Factor Time-Domain SQUID Multiplexer

    NASA Astrophysics Data System (ADS)

    Prêle, D.; Voisin, F.; Piat, M.; Decourcelle, T.; Perbost, C.; Chapron, C.; Rambaud, D.; Maestre, S.; Marty, W.; Montier, L.

    2016-01-01

    A cryogenic 128:1 Time-Domain Multiplexer (TDM) has been developed for the readout of kilo-pixel Transition Edge Sensor (TES) arrays dedicated to the Q&U Bolometric Interferometer for Cosmology (QUBIC) instrument which aims to measure the B-mode polarization of the Cosmic Microwave Background. Superconducting QUantum Interference Devices (SQUIDs) are usually used to read out TESs. Moreover, SQUIDs are used to build TDM by biasing sequentially the SQUIDs connected together—one for each TES. In addition to this common technique which allows a typical 32 multiplexing factor, a cryogenic integrated circuit provides a 4:1 second multiplexing stage. This cryogenic integrated circuit is one of the original part of our TDM achieving an unprecedented 128 multiplexing factor. We present these two dimension TDM stages: topology of the SQUID multiplexer, operation of the cryogenic integrated circuit, and integration of the full system to read out a TES array dedicated to the QUBIC instrument. Flux-locked loop operation in multiplexed mode is also discussed.

  11. Improved Readout Scheme for SQUID-Based Thermometry

    NASA Technical Reports Server (NTRS)

    Penanen, Konstantin

    2007-01-01

    An improved readout scheme has been proposed for high-resolution thermometers, (HRTs) based on the use of superconducting quantum interference devices (SQUIDs) to measure temperature- dependent magnetic susceptibilities. The proposed scheme would eliminate counting ambiguities that arise in the conventional scheme, while maintaining the superior magnetic-flux sensitivity of the conventional scheme. The proposed scheme is expected to be especially beneficial for HRT-based temperature control of multiplexed SQUIDbased bolometer sensor arrays. SQUID-based HRTs have become standard for measuring and controlling temperatures in the sub-nano-Kelvin temperature range in a broad range of low-temperature scientific and engineering applications. A typical SQUIDbased HRT that utilizes the conventional scheme includes a coil wound on a core made of a material that has temperature- dependent magnetic susceptibility in the temperature range of interest. The core and the coil are placed in a DC magnetic field provided either by a permanent magnet or as magnetic flux inside a superconducting outer wall. The aforementioned coil is connected to an input coil of a SQUID. Changes in temperature lead to changes in the susceptibility of the core and to changes in the magnetic flux detected by the SQUID. The SQUID readout instrumentation is capable of measuring magnetic-flux changes that correspond to temperature changes down to a noise limit .0.1 nK/Hz1/2. When the flux exceeds a few fundamental flux units, which typically corresponds to a temperature of .100 nK, the SQUID is reset. The temperature range can be greatly expanded if the reset events are carefully tracked and counted, either by a computer running appropriate software or by a dedicated piece of hardware.

  12. Noise properties of high-temperature superconducting dc-SQUID gradiometers

    NASA Astrophysics Data System (ADS)

    Seidel, P.; Becker, C.; Steppke, A.; Foerster, T.; Wunderlich, S.; Grosse, V.; Pietzcker, R.; Schmidl, F.

    2007-09-01

    We have developed different types of superconducting magnetic field sensors based on high temperature superconducting (HTS) thin films. Here, we describe the fabrication of single layer dc-SQUID gradiometers with bicrystal Josephson junctions for operation in a flip-chip configuration to improve sensor performance. High-quality thin films are known to be essential in achieving suitable electrical properties in these superconducting devices. The influence of sample processing on sensor performance is discussed. The most important parameter for practical applications is the field gradient resolution of the investigated dc-SQUID sensors. To determine this parameter for different gradiometer layouts we measured their noise properties in unshielded as well as magnetically or electrically shielded environments.

  13. Synchronous motor with HTS-2G wires

    NASA Astrophysics Data System (ADS)

    Dezhin, D.; Ilyasov, R.; Kozub, S.; Kovalev, K.; Verzhbitsky, L.

    2014-05-01

    One of the applications of new high-temperature superconductor materials (HTS) is field coils for synchronous electrical machines. The use of YBCO 2G HTS tapes (HTS-2G) allows increasing of magnetic flux density in the air gap, which will increase the output power and reduce the dimensions of the motor. Such motors with improved characteristics can be successfully used in transportation as traction motor. In MAI-based "Center of Superconducting machines and devices" with the support of "Rosatom" has been designed and tested a prototype of the 50 kW synchronous motor with radial magnetic flux from a field-coils based on HTS-2G tapes. The experimental and theoretical results are presented.

  14. TES Detector Noise Limited Readout Using SQUID Multiplexers

    NASA Technical Reports Server (NTRS)

    Staguhn, J. G.; Benford, D. J.; Chervenak, J. A.; Khan, S. A.; Moseley, S. H.; Shafer, R. A.; Deiker, S.; Grossman, E. N.; Hilton, G. C.; Irwin, K. D.

    2004-01-01

    The availability of superconducting Transition Edge Sensors (TES) with large numbers of individual detector pixels requires multiplexers for efficient readout. The use of multiplexers reduces the number of wires needed between the cryogenic electronics and the room temperature electronics and cuts the number of required cryogenic amplifiers. We are using an 8 channel SQUID multiplexer to read out one-dimensional TES arrays which are used for submillimeter astronomical observations. We present results from test measurements which show that the low noise level of the SQUID multiplexers allows accurate measurements of the TES Johnson noise, and that in operation, the readout noise is dominated by the detector noise. Multiplexers for large number of channels require a large bandwidth for the multiplexed readout signal. We discuss the resulting implications for the noise performance of these multiplexers which will be used for the readout of two dimensional TES arrays in next generation instruments.

  15. Development of HTS Magnet for Rotating Gantry

    NASA Astrophysics Data System (ADS)

    Tasaki, Kenji; Koyanagi, Kei; Takayama, S. Shigeki; Ishii, Yusuke; Kurusu, Tsutomu; Amemiya, Naoyuki; Ogitsu, Toru; iwata, Yoshiyuki; Noda, Koji

    The effectiveness of heavy-ion radiotherapy for cancer treatment has been recognized by medical experts and the public. However, due to the large size of the equipment, this therapy has not been widely adopted. In particular, the rotating gantries used to irradiate patients with the heavy-ion beams from any direction may be as heavy as 600 tons in our estimation. By employing high-temperature superconducting (HTS) wires in these rotating gantries and increasing the magnetic field generated by the deflecting coils, the total weight of the rotating gantry can be reduced to around the weight of those used for proton radiotherapy. A project for developing an HTS deflecting magnet for heavy-ion radiotherapy has been underway since 2013, supported by the Japanese Ministry of Economy, Trade and Industry (METI) and the Japan Agency for Medical Research and Development (AMED). The aim of this project is to develop fundamental technologies for designing and fabricating HTS deflecting magnets, such as irregular magnetic field estimating techniques, design technology for HTS magnets, high-precision HTS coil winding technology, AC loss estimating techniques, and thermal runaway estimating techniques and to fabricate a small model of an HTS deflecting magnet and evaluate its performance. In this paper, the project's progress will be described.

  16. Squid rocket science: How squid launch into air

    NASA Astrophysics Data System (ADS)

    O'Dor, Ron; Stewart, Julia; Gilly, William; Payne, John; Borges, Teresa Cerveira; Thys, Tierney

    2013-10-01

    Squid not only swim, they can also fly like rockets, accelerating through the air by forcefully expelling water out of their mantles. Using available lab and field data from four squid species, Sthenoteuthis pteropus, Dosidicus gigas, Illex illecebrosus and Loligo opalescens, including sixteen remarkable photographs of flying S. pteropus off the coast of Brazil, we compared the cost of transport in both water and air and discussed methods of maximizing power output through funnel and mantle constriction. Additionally we found that fin flaps develop at approximately the same size range as flight behaviors in these squids, consistent with previous hypotheses that flaps could function as ailerons whilst aloft. S. pteropus acceleration in air (265 body lengths [BL]/s2; 24.5m/s2) was found to exceed that in water (79BL/s2) three-fold based on estimated mantle length from still photos. Velocities in air (37BL/s; 3.4m/s) exceed those in water (11BL/s) almost four-fold. Given the obvious advantages of this extreme mode of transport, squid flight may in fact be more common than previously thought and potentially employed to reduce migration cost in addition to predation avoidance. Clearly squid flight, the role of fin flaps and funnel, and the energetic benefits are worthy of extended investigation.

  17. Paleomagnetic Analysis Using SQUID Microscopy

    NASA Technical Reports Server (NTRS)

    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.

  18. SQUID holder with high magnetic shielding

    NASA Technical Reports Server (NTRS)

    Rigby, K. W.; Marek, D.; Chui, T. C. P.

    1990-01-01

    A SQUID holder designed for high magnetic shielding is discussed. It is shown how to estimate the attenuation of the magnetic field from the normal magnetic modes for an approximate geometry. The estimate agrees satisfactorily with the attenuation measured with a commercial RF SQUID installed in the holder. The holder attenuates external magnetic fields by more than 10 to the 9th at the SQUID input. With the SQUID input shorted, the response to external fields is 0.00001 Phi(0)/G.

  19. Flux Compression in HTS Films

    NASA Astrophysics Data System (ADS)

    Mikheenko, P.; Colclough, M. S.; Chakalov, R.; Kawano, K.; Muirhead, C. M.

    We report on experimental investigation of the effect of flux compression in superconducting YBa2Cu3Ox (YBCO) films and YBCO/CMR (Colossal Magnetoresistive) multilayers. The flux compression produces positive magnetic moment (m) upon the cooling in a field from above to below the critical temperature. We found effect of compression in all measured films and multilayers. In accordance with theoretical calculations, m is proportional to applied magnetic field. The amplitude of the effect depends on the cooling rate, which suggests the inhomogeneous cooling as its origin. The positive moment is always very small, a fraction of a percent of the ideal diamagnetic response. A CMR layer in contact with HTS decreases the amplitude of the effect. The flux compression weakly depends on sample size, but sensitive to its form and topology. The positive magnetic moment does not appear in bulk samples at low rates of the cooling. Our results show that the main features of the flux compression are very different from those in Paramagnetic Meissner effect observed in bulk high temperature superconductors and Nb disks.

  20. HTS Wire Development Workshop: Proceedings

    SciTech Connect

    Not Available

    1994-07-01

    The 1994 High-Temperature Superconducting Wire Development Workshop was held on February 16--17 at the St. Petersburg Hilton and Towers in St. Petersburg, Florida. The meeting was hosted by Florida Power Corporation and sponsored by the US Department of Energy`s Superconductivity Program for Electric Power Systems. The meeting focused on recent high-temperature superconducting wire development activities in the Department of Energy`s Superconductivity Systems program. The meeting opened with a general discussion on the needs and benefits of superconductivity from a utility perspective, the US global competitiveness position, and an outlook on the overall prospects of wire development. The meeting then focused on four important technology areas: Wire characterization: issues and needs; technology for overcoming barriers: weak links and flux pinning; manufacturing issues for long wire lengths; and physical properties of HTS coils. Following in-depth presentations, working groups were formed in each technology area to discuss the most important current research and development issues. The working groups identified research areas that have the potential for greatly enhancing the wire development effort. These areas are discussed in the summary reports from each of the working groups. This document is a compilation of the workshop proceedings including all general session presentations and summary reports from the working groups.

  1. Tracking Electromagnetic Energy With SQUIDs

    NASA Technical Reports Server (NTRS)

    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.

  2. R&D ERL: HTS Solenoid

    SciTech Connect

    Gupta, R.; Muratore, J.; Plate, S.

    2010-01-01

    An innovative feature of the ERL project is the use of a solenoid made with High Temperature Superconductor (HTS) with the Superconducting RF cavity. The HTS solenoid design offers many advantages because of several unique design features. Typically the solenoid is placed outside the cryostat which means that the beam gets significantly defused before a focusing element starts. In the current design, the solenoid is placed inside the cryostat which provides an early focusing structure and thus a significant reduction in the emittance of the electron beam. In addition, taking full advantage of the high critical temperature of HTS, the solenoid has been designed to reach the required field at {approx}77 K, which can be obtained with liquid nitrogen. This significantly reduces the cost of testing and allows a variety of critical pre-tests which would have been prohibitively expensive at 4 K in liquid helium because of the additional requirements of cryostat and associated facilities.

  3. A planar second-order DC SQUID gradiometer.

    PubMed

    Carelli, P; Chiaventi, L; Leoni, R; Pullano, M; Schirripa Spagnolo, G

    1991-01-01

    In this work we describe a DC SQUID gradiometer, sensitive to the second spatial derivative of the magnetic field. The sensitive area of the gradiometer is the inductive body of the DC SQUID itself. The isoflux line distribution generated by a dipolar source, obtained by performing magnetic measurements with an array of such detectors, is relatively complicated, but its localisation capability is similar to that one usually achieves with axial detector arrays. Planar gradiometers also show a better resolution for near sources and a stronger rejection of far disturbances. The final device is expected to have an inductance of a few hundreds of pH in order to obtain performances typical of a low noise DC SQUID. The pick-up coils will be the combination of four square holes of 500 microns side with a 1.05 cm baseline. Due to the magnetic field concentration (in the final device it can be a factor 10) the gradiometer will have a sensitivity of 10(-11) T m-2 Hz-1/2 and a field sensitivity of about 2 fT Hz-1/2. Some preliminary results, obtained on detectors with an intermediate area between the prototype and final device, are reported here. The process used to fabricate this second-order gradiometer is based on Nb-NbO chi-PbAuIn Josephson tunnel junctions. Some possible improvements will also be described. PMID:1807874

  4. Cold SQUIDs and hot samples

    SciTech Connect

    Lee, T.S.C. |

    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.

  5. How the SQUID was born

    NASA Astrophysics Data System (ADS)

    Silver, Arnold H.

    2006-05-01

    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.

  6. Hybrid Current Lead Design of HTS SMES

    NASA Astrophysics Data System (ADS)

    Ge, T.; Ren, L.; He, Q.; Jiao, F.; Dong, H.; Jin, T.; Zhou, S.

    In application of Superconducting magnetic energy storage device (SMES), current lead represents a key development component. This paper will focus on parameters and structure design of hybrid high-temperature superconductor (HTS) current lead in a SMES with 100 kJ/100 kW class. Based on the theoretical analysis, finite element simulation (FEA) has been used. It studies the thermal influence of variable cross-sectional area, HTS material and the connection between current lead and cryocooler. Some improvements have been proposed to reduce heat losses. At the end of this paper, a whole procedure about hybrid current lead design is given.

  7. Improved Sensing Coils for SQUIDs

    NASA Technical Reports Server (NTRS)

    Penanen, Konstantin; Hahn, Inseob; Eom, Byeong Ho

    2007-01-01

    An improvement in the design and fabrication of sensing coils of superconducting quantum interference device (SQUID) magnetometers has been proposed to increase sensitivity. It has been estimated that, in some cases, it would be possible to increase sensitivity by about half or to reduce measurement time correspondingly. The pertinent aspects of the problems of design and fabrication can be summarized as follows: In general, to increase the sensitivity of a SQUID magnetometer, it is necessary to maximize the magnetic flux enclosed by the sensing coil while minimizing the self-inductance of this coil. It is often beneficial to fabricate the coil from a thicker wire to reduce its self-inductance. Moreover, to optimize the design of the coil with respect to sensitivity, it may be necessary to shape the wire to other than a commonly available circular or square cross-section. On the other hand, it is not practical to use thicker superconducting wire for the entire superconducting circuit, especially if the design of a specific device requires a persistent-current loop enclosing a remotely placed SQUID sensor. It may be possible to bond a thicker sensing-coil wire to thinner superconducting wires leading to a SQUID sensor, but it could be difficult to ensure reliable superconducting connections, especially if the bonded wires are made of different materials. The main idea is to mold the sensing coil in place, to more nearly optimum cross sectional shape, instead of making the coil by winding standard pre-fabricated wire. For this purpose, a thin superconducting wire loop that is an essential part of the SQUID magnetometer would be encapsulated in a form that would serve as a mold. A low-melting-temperature superconducting metal (e.g., indium, tin, or a lead/tin alloy) would be melted into the form, which would be sized and shaped to impart the required cross section to the coil thus formed.

  8. Meta-Atom Interactions and Coherent Response in rf SQUID Metamaterials

    NASA Astrophysics Data System (ADS)

    Trepanier, Melissa; Zhang, Daimeng; Mukhanov, Oleg; Jung, Philipp; Butz, Susanne; Koshelets, V. P.; Ustinov, Alexey; Anlage, Steven

    2015-03-01

    An rf SQUID (radio frequency superconducting quantum interference device) metamaterial can be modeled as an array of coupled nonlinear oscillators with resonant frequencies that are extremely tunable with temperature, dc magnetic field, and rf current. The metamaterial is driven by an external rf field and its response to that field defines its metamaterial characteristics. In the presence of disorder (nonuniform applied dc magnetic flux for instance) the SQUIDs may or may not oscillate coherently in response to the external rf field. Since we are interested in metamaterial applications, a strong coherent response is desirable. The coherence is affected by a variety of factors including flux uniformity, array size, degree of coupling, strength of the driving field, and uniformity in SQUID parameters. In this talk we will present experimental and simulation results exploring the effect of these parameters on coherence. This work is supported by the NSF-GOALI and OISE programs through Grant # ECCS-1158644, and CNAM.

  9. Total AC loss study of 2G HTS coils for fully HTS machine applications

    NASA Astrophysics Data System (ADS)

    Zhang, Min; Yuan, Weijia; Kvitkovic, Jozef; Pamidi, Sastry

    2015-11-01

    The application of HTS coils for fully HTS machines has become a new research focus. In the stator of an electrical machine, HTS coils are subjected to a combination of an AC applied current and AC external magnetic field. There is a phase shift between the AC current and AC magnetic field. In order to understand and estimate the total AC loss of HTS coils for electrical machines, we designed and performed a calorimetric measurement for a 2G HTS racetrack coil. Our measurement indicates that the total AC loss is greatly influenced by the phase shift between the applied current and the external magnetic field when the magnetic field is perpendicular to the tape surface. When the applied current and the external magnetic field are in phase, the total AC loss is the highest. When there is a 90 degree phase difference, the total AC loss is the lowest. In order to explain this phenomenon, we employ H formulation and finite element method to model the 2G HTS racetrack coil. Our calculation agrees well with experimental measurements. Two parameters are defined to describe the modulation of the total AC loss in terms of phase difference. The calculation further reveals that the influence of phase difference varies with magnetic field direction. The greatest influence of phase difference is in the perpendicular direction. The study provides key information for large-scale 2G HTS applications, e.g. fully HTS machines and superconducting magnetic energy storage, where the total AC loss subjected to both applied currents and external magnetic fields is a critical parameter for the design.

  10. Development of a brushless HTS exciter for a 10 kW HTS synchronous generator

    NASA Astrophysics Data System (ADS)

    Bumby, Chris W.; Badcock, Rodney A.; Sung, Hae-Jin; Kim, Kwang-Min; Jiang, Zhenan; Pantoja, Andres E.; Bernardo, Patrick; Park, Minwon; Buckley, Robert G.

    2016-02-01

    HTS synchronous generators, in which the rotor coils are wound from high-T c superconducting wire, are exciting attention due to their potential to deliver very high torque and power densities. However, injection of the large DC currents required by the HTS rotor coils presents a technical challenge. In this paper we discuss the development of a brushless HTS exciter which operates across the cryostat wall to inject a superconducting DC current into the rotor coil circuit. This approach fundamentally alters the thermal load upon the cryogenic system by removing the need for thermally inefficient normal-conducting current leads. We report results from an experimental laboratory device and show that it operates as a constant voltage source with an effective internal resistance. We then discuss the design of a prototype HTS-PM exciter based on our experimental device, and describe its integration with a demonstration HTS generator. This 200 RPM, 10 kW synchronous generator comprises eight double pancake HTS rotor coils which are operated at 30 K, and are energised to 1.5 T field through the injection of 85 A per pole. We show how this excitation can be achieved using an HTS-PM exciter consisting of 12 stator poles of 12 mm YBCO coated-conductor wire and an external permanent magnet rotor. We demonstrate that such an exciter can excite the rotor windings of this generator without forming a thermal-bridge across the cryostat wall. Finally, we provide estimates of the thermal load imposed by our prototype HTS-PM exciter on the rotor cryostat. We show that duty cycle operation of the device ensures that this heat load can be minimised, and that it is substantially lower than that of equivalently-rated conventional current leads.

  11. HTS axial flux induction motor with analytic and FEA modeling

    NASA Astrophysics Data System (ADS)

    Li, S.; Fan, Y.; Fang, J.; Qin, W.; Lv, G.; Li, J. H.

    2013-11-01

    This paper presents a high-temperature superconductor (HTS) axial-flux induction motor, which can output levitation force and torque simultaneously. In order to analyze the character of the force, analytic method and finite element method are adopted to model the motor. To make sure the HTS can carry sufficiently large current and work well, the magnetic field distribution in HTS coil is calculated. An effective method to improve the critical current of HTS coil is presented. Then, AC losses in HTS windings in the motor are estimated and tested.

  12. Phased-array components for the High-Temperature Superconducting Space Experiment (HTSSE). Final report

    SciTech Connect

    Not Available

    1991-06-07

    A new class of X-band phase shifters using the distributed Josephson inductance (DJI) effect were delivered to NRL for the HTS Space Experiment project. Phase shifts were observed above 77 K, and large phase shifts were observed at 65 K and below. This narrow-band device was developed as a first step to a broadband device. A total of 40 HTS SQUIDs were successfully integrated into a monolithic circuit. Measurement of the temperature dependance of the Q of a resonator in June 1990 and in February 1991 showed no significant change due to aging. A total of seven X-band phase shifters were fabricated, and five were delivered to Naval Research Laboratory. The HTS phase shifter consists of a low loss YBa2Cu3O7 microstrip resonator with 40 SQUID devices monolithically imbedded into the transmission line. This narrow-band device was developed as a first step to a broadband device.

  13. Phased array components for the High Temperature Superconducting Space Experiment (HTSSE)

    NASA Astrophysics Data System (ADS)

    1991-06-01

    A new class of X-band phase shifters using the distributed Josephson inductance (DJI) effect were delivered to NRL for the HTS Space Experiment project. Phase shifts were observed above 77 K, and large phase shifts were observed at 65 K and below. This narrow-band device was developed as a first step to a broadband device. A total of 40 HTS SQUIDs were successfully integrated into a monolithic circuit. Measurement of the temperature dependence of the Q of a resonator in June 1990 and in February 1991 showed no significant change due to aging. A total of seven X-band phase shifters were fabricated, and five were delivered to Naval Research Laboratory. The HTS phase shifter consists of a low loss YBa2Cu3O7 microstrip resonator with 40 SQUID devices monolithically imbedded into the transmission line. This narrow-band device was developed as a first step to a broadband device.

  14. Foraging ecology and movement patterns of jumbo squid (Dosidicus gigas) in the California Current System

    NASA Astrophysics Data System (ADS)

    Field, John C.; Elliger, Carl; Baltz, Ken; Gillespie, Graham E.; Gilly, William F.; Ruiz-Cooley, R. I.; Pearse, Devon; Stewart, Julia S.; Matsubu, William; Walker, William A.

    2013-10-01

    From 2002 to 2010, the jumbo squid (Dosidicus gigas) has been regularly encountered in large numbers throughout the California Current System (CCS). This species, usually found in subtropical waters, could affect coastal pelagic ecosystems and fisheries as both predator and prey. Neither the abundance of jumbo squid nor the optimal ocean conditions in which they flourish are well known. To understand better the potential impacts of this species on both commercial fisheries and on food-web structure we collected nearly 900 specimens from waters of the CCS, covering over 20° of latitude, over a range of depths and seasons. We used demographic information (size, sex, and maturity state) and analyzed stomach contents using morphological and molecular methods to best understand the foraging ecology of this species in different habitats of the CCS. Squid were found to consume a broad array of prey. Prey in offshore waters generally reflected the forage base reported in previous studies (mainly mesopelagic fishes and squids), whereas in more coastal waters (shelf, shelf break and slope habitats) squid foraged on a much broader mix that included substantial numbers of coastal pelagic fishes (Pacific herring and northern anchovy, as well as osmerids and salmonids in northern waters) and groundfish (Pacific hake, several species of rockfish and flatfish). We propose a seasonal movement pattern, based on size and maturity distributions along with qualitative patterns of presence or absence, and discuss the relevance of both the movement and distribution of jumbo squid over space and time. We find that jumbo squid are a generalist predator, which feeds primarily on small, pelagic or mesopelagic micronekton but also on larger fishes when they are available. We also conclude that interactions with and potential impacts on ecosystems likely vary over space and time, in response to both seasonal movement patterns and highly variable year-to-year abundance of the squid themselves.

  15. A study on the required performance of a 2G HTS wire for HTS wind power generators

    NASA Astrophysics Data System (ADS)

    Sung, Hae-Jin; Park, Minwon; Go, Byeong-Soo; Yu, In-Keun

    2016-05-01

    YBCO or REBCO coated conductor (2G) materials are developed for their superior performance at high magnetic field and temperature. Power system applications based on high temperature superconducting (HTS) 2G wire technology are attracting attention, including large-scale wind power generators. In particular, to solve problems associated with the foundations and mechanical structure of offshore wind turbines, due to the large diameter and heavy weight of the generator, an HTS generator is suggested as one of the key technologies. Many researchers have tried to develop feasible large-scale HTS wind power generator technologies. In this paper, a study on the required performance of a 2G HTS wire for large-scale wind power generators is discussed. A 12 MW class large-scale wind turbine and an HTS generator are designed using 2G HTS wire. The total length of the 2G HTS wire for the 12 MW HTS generator is estimated, and the essential prerequisites of the 2G HTS wire based generator are described. The magnetic field distributions of a pole module are illustrated, and the mechanical stress and strain of the pole module are analysed. Finally, a reasonable price for 2G HTS wire for commercialization of the HTS generator is suggested, reflecting the results of electromagnetic and mechanical analyses of the generator.

  16. RADIATION RESISTANT HTS QUADRUPOLES FOR RIA.

    SciTech Connect

    GUPTA,R.; ANERELLA,M.; HARRISON,M.; ET AL.

    2004-10-03

    Extremely high radiation, levels with accumulated doses comparable to those in nuclear reactors than in accelerators, and very high heat loads ({approx}15 kw) make the quadrupole magnets in the fragment separator one of the most challenging elements of the proposed Rare Isotope Accelerator (RIA). Removing large heat loads, protecting the superconducting coils against quenching, the long term survivability of magnet components, and in particular, insulation that can retain its functionality in such a harsh environment, are the major challenges associated with such magnets. A magnet design based on commercially available high temperature superconductor (HTS) and stainless steel tape insulation has been developed. HTS will efficiently remove these large heat loads and stainless steel can tolerate these large radiation doses. Construction of a model magnet has been started with several coils already built and tested. This paper presents the basic magnet design, results of the coil tests, the status and the future plans. In addition, preliminary results of radiation calculations are also presented.

  17. Mobile conduction-cooled HTS SMES

    NASA Astrophysics Data System (ADS)

    Ren, L.; Tang, Y.; Li, J.; Shi, J.; Chen, L.; Guo, F.; Fang, J.; Wen, J.

    2010-11-01

    An immovable 35 kJ/7 kW high- Tc superconducting magnetic energy storage (HTS SMES) system had been developed in the Electric Power System Dynamic Simulation Laboratory, Huazhong University of Science and Technology in 2005. In order to adapt for on-site experimental conditions, the mechanical configuration of the magnet is reinforced and the SMES system is assembled in a special container to be freighted to the actual power system for the feasibility study on different applications at different sites. The mobile HTS SMES system had withstood various kinds of poor road surfaces and then arrived at the experimental site on August 18, 2009. In this paper, the reconstructed configuration and the shock absorption of the magnet are presented. The field test results show that the mobile SMES system can operate on the power network at different locations and suppress effectively power fluctuation of the generator terminal.

  18. Cold storage characteristics of mobile HTS magnet

    NASA Astrophysics Data System (ADS)

    Mizuno, Katsutoshi; Miyazaki, Yoshiki; Nagashima, Ken; Kawano, Asumi; Okamura, Tetsuji

    2011-06-01

    A cold storage system specialized in mobile high-temperature superconducting (HTS) magnets (e.g. for magnetically levitated (maglev) vehicles) has been proposed. In this system, a cooling source is detachable and a HTS coil is capable of maintaining superconducting state with its heat capacity. This system allows a considerably lightweight HTS magnet. An apparatus was constructed to evaluate the possibility of using cold storage systems in maglev vehicles. The thermal characteristic of this apparatus was based on a magnet for previous maglev test vehicles [1]. The operational temperature range of the magnet was assumed from 20 K to 50 K. Some experiments indicated that heat conduction by residual gas was not negligible. Especially over 30 K, gas conduction took a large part of heat input. This phenomenon is attributable to reduction of cryopumping effect. However, activated carbon in the apparatus compensates cryopumping effect. A unique heat capacitor was also used to enhance the cold storage effect. Water ice was chosen as a heat capacitor because water ice has a higher heat capacity than metallic materials at cryogenic temperatures. A small amount of water ice also prolonged cryogenic temperature condition. These results indicate 1 day of cold storage is probable in a magnet for maglev vehicles.

  19. Designing HTS coils for magnetic circuits

    SciTech Connect

    Jenkins, R.G.; Jones, H.; Goodall, R.M.

    1996-07-01

    The authors discuss some of the main considerations involved in the design of HTS coils to operate in liquid nitrogen and provide ampere-turns for magnetic circuits in general, and then in particular for a small-scale electromagnetic (i.e, attractive) maglev demonstrator. The most important factor affecting design is the sensitive and strongly anisotropic dependence of HTS tape`s critical current on magnetic field. Any successful design must limit the field in the windings, especially components perpendicular to the tape`s surface (radial components in the case of solenoids), to acceptably low levels such that local critical currents nowhere fall below the operating current. This factor is relevant to the construction of HTS coils for all applications. A second important factor is that the presence of an iron magnetic circuit can greatly alter the flux distribution within the coils from that found when they are in free space. FE modelling has been used to calculate accurate field profiles in proposed designs for comparison with short sample I{sub c}(B) data. They present a design for a maglev demonstrator, illustrating how some of the problems, in particular the reduction of radial field components, may be addressed, and describe its predicted performance.

  20. Progress in development of high capacity magnetic HTS bearings

    NASA Astrophysics Data System (ADS)

    Kummeth, P.; Nick, W.; Neumueller, H.-W.

    2005-10-01

    HTS magnetic bearings are inherently stable without an active feedback system. They provide low frictional losses, no wear and allow operation at high rotational speed without lubrication. So they are very promising for use in motors, generators and turbines. We designed and constructed an HTS radial bearing for use with a 400 kW HTS motor. It consists of alternating axially magnetized permanent magnet rings on the rotor and a segmented YBCO stator. Stator cooling is performed by liquid nitrogen, the temperature of the stator can be adjusted by varying the pressure in the cryogenic vessel. At 68 K maximum radial forces of more than 3.7 kN were found. These results range within the highest radial bearing capacities reported worldwide. The encouraging results lead us to develop a large heavy load HTS radial bearing. Currently a high magnetic gradient HTS bearing for a 4 MVA synchronous HTS generator is under construction.

  1. Analytical derivation of DC SQUID response

    NASA Astrophysics Data System (ADS)

    Soloviev, I. I.; Klenov, N. V.; Schegolev, A. E.; Bakurskiy, S. V.; Kupriyanov, M. Yu

    2016-09-01

    We consider voltage and current response formation in DC superconducting quantum interference device (SQUID) with overdamped Josephson junctions in resistive and superconducting state in the context of a resistively shunted junction (RSJ) model. For simplicity we neglect the junction capacitance and the noise effect. Explicit expressions for the responses in resistive state were obtained for a SQUID which is symmetrical with respect to bias current injection point. Normalized SQUID inductance l=2{{eI}}{{c}}L/{\\hslash } (where I c is the critical current of Josephson junction, L is the SQUID inductance, e is the electron charge and ℏ is the Planck constant) was assumed to be within the range l ≤ 1, subsequently expanded up to l≈ 7 using two fitting parameters. SQUID current response in the superconducting state was considered for arbitrary value of the inductance. The impact of small technological spread of parameters relevant to low-temperature superconductor (LTS) technology was studied, using a generalization of the developed analytical approach, for the case of a small difference of critical currents and shunt resistances of the Josephson junctions, and inequality of SQUID inductive shoulders for both resistive and superconducting states. Comparison with numerical calculation results shows that developed analytical expressions can be used in practical LTS SQUIDs and SQUID-based circuits design, e.g. large serial SQIF, drastically decreasing the time of simulation.

  2. Biofunctional Properties of Enzymatic Squid Meat Hydrolysate

    PubMed Central

    Choi, Joon Hyuk; Kim, Kyung-Tae; Kim, Sang Moo

    2015-01-01

    Squid is one of the most important commercial fishes in the world and is mainly utilized or consumed as sliced raw fish or as processed products. The biofunctional activities of enzymatic squid meat hydrolysate were determined to develop value-added products. Enzymatic squid hydrolysate manufactured by Alcalase effectively quenched 1,1-diphenyl-2-picrylhydrazyl radical, hydroxyl radical, and hydrogen peroxide radical with IC50 values of 311, 3,410, and 111.5 μg/mL, respectively. Angiotensin I-converting enzyme inhibitory activity of squid hydrolysate was strong with an IC50 value of 145.1 μg/mL, while tyrosinase inhibitory activity with an IC50 value of 4.72 mg/mL was moderately low. Overall, squid meat hydrolysate can be used in food or cosmetic industries as a bioactive ingredient and possibly be used in the manufacture of seasoning, bread, noodle, or cosmetics. PMID:25866752

  3. Performance of a novel squid-based superconducting imaging-surface magnetoencephalography system

    SciTech Connect

    Matlochov, A.; Espy, M. A.; Volegov, P.; Maharajh, K.; Flynn, E. R.; Kraus, Robert H., Jr.

    2001-01-01

    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 helmetlike 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 8mm x 8mm SQUID magnetometers with 0.84nT/F sensitivity and <3fT/vHz noise. A series of phantom experiments to verify system efficacy have been completed. Simple dry-wire phantoms were used to eliminate model dependence from our results. Phantom coils were distributed throughout the volume encompassed by the array with a variety of orientations. Each phantom coil was precisely machined and located to better than 25{micro}m and 10mRad accuracy. Excellent agreement between model-calculated and measured magnetic field distributions of all phantom coil 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 0.5mm at all locations with a mean of better than 0.3mm.

  4. Reliable commercial HTS wire for power applications

    NASA Astrophysics Data System (ADS)

    Kellers, Jürgen; Masur, Lawrence J.

    2002-08-01

    The production of HTS wire for power applications is increasingly maturing into industrial dimensions. The most widely considered manufacturing method for this conductor is the BSCCO-2223-OPIT route, used internationally by many organizations, including American Superconductor. Significant advances in HTS wire technology have been made in the past years, with currently a guaranteed minimum critical current performance of 115 A at 77 K over commercial long length. For the HTS wire itself this is equivalent to an engineering current density of 13.5 kA/cm 2. During the past 18 months, American Superconductor increased its HTS wire manufacturing capacity in its Westborough operations from 250 to 500 km/year to meet the increased demand for development and demonstration purposes. While this level of quality and quantity is sufficient to demonstrate technical feasibility and reliability of prototype power applications, it cannot satisfy fully commercial requirements for economic viability. To address broader markets with a commercially viable product, a price level of $50/(kA m) is possible with BSCCO-2223-OPIT when manufactured in much larger quantities. Therefore, American Superconductor is currently siting a new facility dedicated solely to the manufacturing of BSCCO-OPIT-2223 wire in quantities of 10,000 km/year. Key initial applications for this wire are power transmission cables, industrial motors and electrical generators. This paper will report on the performance and reliability testing of BSCCO-2223 wires. We will discuss the electrical, bending, tensile, and fatigue testing results of wires manufactured for applications such as American Superconductor's 5000 hp ultra-compact motor. Due to their compactness, these motors will be less expensive to manufacture compared with conventional motors and will be more energy efficient. We will also review the stringent electrical, mechanical, and environmental testing developed jointly by American Superconductor and

  5. High output power electric motors with bulk HTS elements

    NASA Astrophysics Data System (ADS)

    Kovalev, L. K.; Ilushin, K. V.; Kovalev, K. L.; Penkin, V. T.; Poltavets, V. N.; Koneev, S. M.-A.; Akimov, I. I.; Gawalek, W.; Oswald, B.; Krabbes, G.

    2003-04-01

    New types of electric machines with the rotors containing bulk HTS (YBCO and Bi-Ag) elements are presented. Different schematics of hysteresis, reluctance, “trapped field” and composed synchronous HTS machines are discussed. The two-dimensional mathematical models describing the processes in such types of HTS machines were developed on the basis of the theoretical analysis of the electrodynamic and hysteresis processes in the single-domain and polycrystal YBCO ceramic samples and plate shape Bi-Ag elements. The test results of the series of hysteresis, reluctance, “trapped field” and composed with permanent magnets HTS motors with output power rating 0.1-18 kW and current frequency 50 and 400 Hz are given. These results show that in the media of liquid nitrogen the specific output power per one weight unit of HTS motors is 4-7 times better than for conventional electric machines. Comparison of the theoretical and experimental characteristics of the developed HTS motors show that they are in good agreement. The test results for liquid nitrogen cryogenic pump system with hysteresis 500 W HTS motor are discussed. The designs and first test results of HTS motor operating in the media of liquid nitrogen with output power 100 kW and power factor more than 0.8 are given. Future development and applications of new types of HTS motors for aerospace technology, on-land industry and transport systems are discussed.

  6. Failure Analysis of CCD Image Sensors Using SQUID and GMR Magnetic Current Imaging

    NASA Technical Reports Server (NTRS)

    Felt, Frederick S.

    2005-01-01

    During electrical testing of a Full Field CCD Image Senor, electrical shorts were detected on three of six devices. These failures occurred after the parts were soldered to the PCB. Failure analysis was performed to determine the cause and locations of these failures on the devices. After removing the fiber optic faceplate, optical inspection was performed on the CCDs to understand the design and package layout. Optical inspection revealed that the device had a light shield ringing the CCD array. This structure complicated the failure analysis. Alternate methods of analysis were considered, including liquid crystal, light and thermal emission, LT/A, TT/A SQUID, and MP. Of these, SQUID and MP techniques were pursued for further analysis. Also magnetoresistive current imaging technology is discussed and compared to SQUID.

  7. Multiplexing of Hot-Electron Nanobolometers Using Microwave SQUIDs

    NASA Astrophysics Data System (ADS)

    Karasik, Boris S.; Day, Peter K.; Kawamura, Jonathan H.; Bumble, Bruce; LeDuc, Henry G.

    2009-12-01

    We have obtained the first data on the multiplexed operation of titanium hot-electron bolometers (HEB). Because of their low thermal conductance and small electron heat capacity nanobolometers are particularly interesting as sensors for far-infrared spectroscopy and mid- and near-IR calorimetry. However, the short time constant of these devices (˜μs at 300-400 mK) makes time domain or audio-frequency domain multiplexing impractical. The Microwave SQUID (MSQUID) approach pursued in this work uses dc SQUIDs coupled to X-band microresonators which are, in turn, coupled to a transmission line. We used a 4-element array of Ti HEBs operated at 415 mK in a He3 dewar with an optical fiber access. The microwave signal exhibited 10-MHz wide resonances at individual MSQUD frequencies between 9 GHz and 10 GHz. The resonance depth is modulated by the current through the bolometer via a change of the SQUID flux state. The transmitted signal was amplified by a cryogenic amplifier and downconverted to baseband using an IQ mixer. A 1-dB per Ω0/2 responsivity was sufficient for keeping the system noise at the level of ˜2 pA/Hz1/2. This is more than an order of magnitude smaller than phonon noise in the HEB. The devices were able to detect single near-IR photons (1550 nm) with a time constant of 3.5 μs. Follow-on work will scale the array to larger size and will address the microwave frequency signal generation and processing using a digital transceiver.

  8. Multiplexing of Hot-Electron Nanobolometers Using Microwave SQUIDs

    NASA Technical Reports Server (NTRS)

    Karasik, Boris S.; Day, Peter K.; Kawamura, Jonathan H.; Bumble, Bruce; LeDuc, Henry G.

    2009-01-01

    We have obtained the first data on the multiplexed operation of titanium hot-electron bolometers (HEB). Because of their low thermal conductance and small electron heat capacity nanobolometers are particularly interesting as sensors for far-infrared spectroscopy and mid- and near-IR calorimetry. However, the short time constant of these devices (approximately microseconds at 300-400 mK) makes time domain or audio-frequency domain multiplexing impractical. The Microwave SQUID (MSQUID) approach pursued in this work uses dc SQUIDs coupled to X-band microresonators which are, in turn, coupled to a transmission line. We used a 4-element array of Ti HEBs operated at 415 mK in a He3 dewar with an optical fiber access. The microwave signal exhibited 10-MHz wide resonances at individual MSQUD frequencies between 9 GHz and 10 GHz. The resonance depth is modulated by the current through the bolometer via a change of the SQUID flux state. The transmitted signal was amplified by a cryogenic amplifier and downconverted to baseband using an IQ mixer. A 1-dB per ??/2 responsivity was sufficient for keeping the system noise at the level of 2 pA/Hz1/2. This is more than an order of magnitude smaller than phonon noise in the HEB. The devices were able to detect single near- IR photons (1550 nm) with a time constant of 3.5 ?s. Follow-on work will scale the array to larger size and will address the microwave frequency signal generation and processing using a digital transceiver.

  9. Study on Thrust Improvement and Ripple Suppression of HTS Linear Switched Reluctance Motor with Coreless HTS Excitation Windings

    NASA Astrophysics Data System (ADS)

    Oto, Satoshi; Hirayama, Tadashi; Kawabata, Shuma

    This paper describes a linear switched reluctance motor (LSRM) in which HTS tapes are used for coreless excitation windings in order to reduce the thrust ripple and normal force. This LSRM consists of a mover with saliency structure, coreless HTS coils and a stator back yoke. In this paper, we first describe the operating principle of the HTS-LSRM. Next, we calculate performances of the HTS-LSRM using 3-D FEM analysis. The effects of the motor structure on the thrust characteristic and normal force characteristics are clarified from the numerical results. Furthermore, we investigate the motor structure for thrust improvement, thrust ripple and normal force reduction.

  10. Commercialization of Medium Voltage HTS Triax TM Cable Systems

    SciTech Connect

    Knoll, David

    2012-12-31

    The original project scope that was established in 2007 aimed to install a 1,700 meter (1.1 mile) medium voltage HTS Triax{TM} cable system into the utility grid in New Orleans, LA. In 2010, however, the utility partner withdrew from the project, so the 1,700 meter cable installation was cancelled and the scope of work was reduced. The work then concentrated on the specific barriers to commercialization of HTS cable technology. The modified scope included long-length HTS cable design and testing, high voltage factory test development, optimized cooling system development, and HTS cable life-cycle analysis. In 2012, Southwire again analyzed the market for HTS cables and deemed the near term market acceptance to be low. The scope of work was further reduced to the completion of tasks already started and to testing of the existing HTS cable system in Columbus, OH. The work completed under the project included: • Long-length cable modeling and analysis • HTS wire evaluation and testing • Cable testing for AC losses • Optimized cooling system design • Life cycle testing of the HTS cable in Columbus, OH • Project management. The 200 meter long HTS Triax{TM} cable in Columbus, OH was incorporated into the project under the initial scope changes as a test bed for life cycle testing as well as the site for an optimized HTS cable cooling system. The Columbus cable utilizes the HTS TriaxTM design, so it provided an economical tool for these of the project tasks.

  11. Aperture effects in squid jet propulsion.

    PubMed

    Staaf, Danna J; Gilly, William F; Denny, Mark W

    2014-05-01

    Squid are the largest jet propellers in nature as adults, but as paralarvae they are some of the smallest, faced with the inherent inefficiency of jet propulsion at a low Reynolds number. In this study we describe the behavior and kinematics of locomotion in 1 mm paralarvae of Dosidicus gigas, the smallest squid yet studied. They swim with hop-and-sink behavior and can engage in fast jets by reducing the size of the mantle aperture during the contraction phase of a jetting cycle. We go on to explore the general effects of a variable mantle and funnel aperture in a theoretical model of jet propulsion scaled from the smallest (1 mm mantle length) to the largest (3 m) squid. Aperture reduction during mantle contraction increases propulsive efficiency at all squid sizes, although 1 mm squid still suffer from low efficiency (20%) because of a limited speed of contraction. Efficiency increases to a peak of 40% for 1 cm squid, then slowly declines. Squid larger than 6 cm must either reduce contraction speed or increase aperture size to maintain stress within maximal muscle tolerance. Ecological pressure to maintain maximum velocity may lead them to increase aperture size, which reduces efficiency. This effect might be ameliorated by nonaxial flow during the refill phase of the cycle. Our model's predictions highlight areas for future empirical work, and emphasize the existence of complex behavioral options for maximizing efficiency at both very small and large sizes. PMID:24501132

  12. First demonstration of transcontinental SQUID magnetometry (Invited)

    NASA Astrophysics Data System (ADS)

    Fourie, C.; Febvre, P.; Pozzo di Borgo, E.; Waysand, G.; Gouws, D.; Saunderson, E.; Henry, S.; Gaffet, S.; Janse van Vuuren, L.; Lochner, E. T.; Matladi, T.; Kwisanga, C.

    2013-12-01

    We present the first simultaneous measurements from an ultra-sensitive dual-node transcontinental SQUID magnetometer network, available in real time on the internet. A three-axis low temperature SQUID sensor at LSBB Underground Research Laboratory, Rustrel, France (43.841 N, 5.484 E) and a two-axis high temperature SQUID sensor at SANSA Space Science in Hermanus, South Africa (34.424 S, 19.223 E), form the sensitive nodes of the network. Data are measured and GPS time stamped continuously at 125 Hz. The low-Tc SQUID at LSBB URL (known as a [SQUID]2 system) is inside a shielded steel capsule underneath 500 meters of karstic rock, which allows a low magnetic noise floor. The less sensitive high-Tc SQUID at SANSA Space Science is completely unshielded, and housed only in a magnetically neutral hut, 50 metres from a calibrated fluxgate node of the INTERMAGNET network, to protect it against the weather. The network, which is more sensitive than observatory fluxgate magnetometers, detects Earth's magnetosphere pulsations, Schumann waves, mesopause resonance, breathing modes of the Earth and oceanic swell. Our goal is further to extract directional or polarization information if earthquake precursors are observed again, as with the Sichuan-Wenchuan earthquake on 12 May 2008. In the medium term, we are exploring the possibility to extend the network with more spatially distributed SQUID sensors, such as at the South African National Antarctic Expedition's SANAE IV base in Antarctica.

  13. Thermal analysis for the HTS stator consisting of HTS armature windings and an iron core for a 2.5 kW HTS generator

    NASA Astrophysics Data System (ADS)

    Song, P.; Qu, T.-M.; Lai, L.-F.; Wu, M.-S.; Yu, X.-Y.; Han, Z.

    2016-05-01

    Most present demonstrations of high-temperature superconducting (HTS) synchronous motors/generators are partially superconducting, only installing HTS coils on the rotor as excitation windings. The possible applicability of HTS armature windings is an interesting research topic because these windings can certainly increase the power density attributed to a potentially high armature loading capacity. In this study, we analysed the thermal behaviours of a developed 2.5 kW-300 rpm synchronous generator prototype that consists of an HTS stator with Bi-2223-Ag armature windings on an iron core and a permanent magnet (PM) rotor. The entire HTS stator, including the iron core, is cooled with liquid nitrogen through conduction cooling. The rated frequency is set at 10 Hz to reduce AC loss. The properties of the HTS windings and the iron core are characterized, and the temperatures in the HTS stator under different operation conditions are measured. The estimated iron loss is 11.5 W under operation in 10 Hz at liquid nitrogen temperature. Conduction cooling through the silicon iron core is sufficient to cool the iron core and to compensate for the temperature increment caused by iron loss. The stable running capacity is limited to 1.6 kW when the armature current is 12.6 A (effective values) due to the increasing temperature in the slots as a result of the AC loss in the HTS coils. The thermal contact between the HTS coils and the cooling media should be improved in the future to take away the heat generated by AC loss.

  14. Structural design of the toroidal configuration of the HTS SMES cooling system

    NASA Astrophysics Data System (ADS)

    Yeom, H. K.; Koh, D. Y.; Ko, J. S.; Kim, H. B.; Hong, Y. J.; Kim, S. H.; Seong, K. C.

    2011-11-01

    The superconducting magnetic energy storage (SMES) system is working on around 30 K, because the magnet is made of high temperature superconductor. To maintain the cryogenic temperature, the superconducting coil is cooled by cryogen, helium gas or liquid neon. But there are some weak points in the cryogen cooling system. For example periodic charge of the cryogen and size is big and so on. So, we have designed the conduction cooling system for toroidal configuration HTS SMES. The toroidal type HTS SMES has some merits, so it is very small magnetic field leakage, and magnetic field applied perpendicular to the tape surface can be reduced. Our system has 28 numbers of HTS double pancake coils and they are arrayed toroidal configuration. The toroidal inner radius is 162 mm, and outer radius is 599 mm, and height is about 162 mm. In this study, we have designed the cooling structure and analyzed temperature distribution of cooling path, thermal stress and deformation of the cooling structure.

  15. Numerical models for ac loss calculation in large-scale applications of HTS coated conductors

    NASA Astrophysics Data System (ADS)

    Quéval, Loïc; Zermeño, Víctor M. R.; Grilli, Francesco

    2016-02-01

    Numerical models are powerful tools to predict the electromagnetic behavior of superconductors. In recent years, a variety of models have been successfully developed to simulate high-temperature-superconducting (HTS) coated conductor tapes. While the models work well for the simulation of individual tapes or relatively small assemblies, their direct applicability to devices involving hundreds or thousands of tapes, e.g., coils used in electrical machines, is questionable. Indeed, the simulation time and memory requirement can quickly become prohibitive. In this paper, we develop and compare two different models for simulating realistic HTS devices composed of a large number of tapes: (1) the homogenized model simulates the coil using an equivalent anisotropic homogeneous bulk with specifically developed current constraints to account for the fact that each turn carries the same current; (2) the multi-scale model parallelizes and reduces the computational problem by simulating only several individual tapes at significant positions of the coil’s cross-section using appropriate boundary conditions to account for the field generated by the neighboring turns. Both methods are used to simulate a coil made of 2000 tapes, and compared against the widely used H-formulation finite-element model that includes all the tapes. Both approaches allow faster simulations of large number of HTS tapes by 1-3 orders of magnitudes, while maintaining good accuracy of the results. Both models can therefore be used to design and optimize large-scale HTS devices. This study provides key advancement with respect to previous versions of both models. The homogenized model is extended from simple stacks to large arrays of tapes. For the multi-scale model, the importance of the choice of the current distribution used to generate the background field is underlined; the error in ac loss estimation resulting from the most obvious choice of starting from a uniform current distribution is revealed.

  16. Superconducting Pathways Through Kilopixel Backshort-Under-Grid Arrays

    NASA Astrophysics Data System (ADS)

    Jhabvala, C. A.; Benford, D. J.; Brekosky, R. P.; Costen, N. P.; Datesman, A. M.; Hilton, G. C.; Irwin, K. D.; Maher, S. F.; Manos, G.; Miller, T. M.; Moseley, S. H.; Sharp, E. H.; Staguhn, J. G.; Wang, F.; Wollack, E. J.

    2016-08-01

    We have demonstrated in the laboratory multiple, fully functional, kilopixel, bolometer arrays for the upgraded instrument, the High-resolution airborne wideband camera plus (HAWC+), for the stratospheric observatory for infrared astronomy (SOFIA). Each kilopixel array consists of three individual components assembled into a single working unit: (1) a filled, Transition Edge Sensor (TES) bolometer array, (2) an infrared, back-termination, and (3) an integrated, two-dimensional superconducting quantum interference device (SQUID) multiplexer readout. Kilopixel TES arrays are directly indium-bump-bonded to a 32 × 40 SQUID multiplexer (MUX) circuit. In order to provide a fully superconducting pathway from the TES to the SQUID readout, numerous superconductor-to-superconductor interfaces must be made. This paper focuses on the fabrication techniques needed to create the superconducting path from the TES, out of the detector membrane, through the wafer, and to the SQUID readout.

  17. Superconducting Pathways Through Kilopixel Backshort-Under-Grid Arrays

    NASA Astrophysics Data System (ADS)

    Jhabvala, C. A.; Benford, D. J.; Brekosky, R. P.; Costen, N. P.; Datesman, A. M.; Hilton, G. C.; Irwin, K. D.; Maher, S. F.; Manos, G.; Miller, T. M.; Moseley, S. H.; Sharp, E. H.; Staguhn, J. G.; Wang, F.; Wollack, E. J.

    2016-01-01

    We have demonstrated in the laboratory multiple, fully functional, kilopixel, bolometer arrays for the upgraded instrument, the High-resolution airborne wideband camera plus (HAWC+), for the stratospheric observatory for infrared astronomy (SOFIA). Each kilopixel array consists of three individual components assembled into a single working unit: (1) a filled, Transition Edge Sensor (TES) bolometer array, (2) an infrared, back-termination, and (3) an integrated, two-dimensional superconducting quantum interference device (SQUID) multiplexer readout. Kilopixel TES arrays are directly indium-bump-bonded to a 32 × 40 SQUID multiplexer (MUX) circuit. In order to provide a fully superconducting pathway from the TES to the SQUID readout, numerous superconductor-to-superconductor interfaces must be made. This paper focuses on the fabrication techniques needed to create the superconducting path from the TES, out of the detector membrane, through the wafer, and to the SQUID readout.

  18. Baseband Feedback Frequency-Division Multiplexing with Low-Power dc-SQUIDs and Digital Electronics for TES X-Ray Microcalorimeters

    NASA Astrophysics Data System (ADS)

    Sakai, K.; Takei, Y.; Yamamoto, R.; Yamasaki, N. Y.; Mitsuda, K.; Hidaka, M.; Nagasawa, S.; Kohjiro, S.; Miyazaki, T.

    2014-08-01

    We are developing frequency-division multiplexing (FDM) systems with baseband feedback for TES X-ray microcalorimeter arrays for use with the DIOS mission. To meet the requirement of limited cooling capacity at cryogenic temperatures, we developed low-power and FDM-optmized dc-SQUIDs. To make maximum use of the SQUIDs, we also developed digital electronics using FPGA evaluation boards and ADC/DAC FMC daughter cards, and evaluated signal-to-noise ratios and gain-bandwidth products.

  19. Linearized superconducting quantum interference device array for high bandwidth frequency-domain readout multiplexing.

    PubMed

    Lanting, T; Dobbs, M; Spieler, H; Lee, A T; Yamamoto, Y

    2009-09-01

    We have designed and demonstrated a superconducting quantum interference device (SQUID) array linearized with cryogenic feedback. To achieve the necessary loop gain, a 300-element series array SQUID is constructed from three monolithic 100-element series arrays. A feedback resistor completes the loop from the SQUID output to the input coil. The short feedback path of this linearized SQUID array (LISA) allows for a substantially larger flux-locked loop bandwidth as compared to a SQUID flux-locked loop that includes a room temperature amplifier. The bandwidth, linearity, noise performance, and 3 Phi(0) dynamic range of the LISA are sufficient for its use in our target application: the multiplexed readout of transition-edge sensor bolometers. PMID:19791952

  20. Design and preliminary results from a high temperature superconducting SQUID milliscope used for non-destructive evaluation

    SciTech Connect

    Espy, M.A.; Atencio, L.; Flynn, E.R.; Kraus, R.H. Jr.; Matlashov, A.

    1998-12-31

    The authors present the design and preliminary results from a SQUID milliscope. The device was designed for nondestructive evaluation (NDE) as part of the Enhanced Surveillance Program at Los Alamos National Laboratory and uses a high temperature superconducting (HTS) SQUID sensor to map magnetic fields induced in the sample. Eddy currents are induced in the conducting sample by a wire coil designed to produce minimal magnetic field at the SQUID when no sample is present. The features of interest are characterized by anomalies in the induced magnetic field. The goal of the instrument is sensitivity to small features generally buried under several intervening layers ({approximately}1--10 mm) of conducting and/or non-conducting materials and robustness of design (i.e., the ability to operate in a noisy, unshielded environment). The device has primarily focused on specific NDE problems such as the ability to detect buried seams in conducting materials and quantify the width of these seams. The authors present the design of the instrument, and some data to demonstrate its capabilities.

  1. Waveform control pulse magnetization for HTS bulk magnet

    NASA Astrophysics Data System (ADS)

    Ida, Tetsuya; Shigeuchi, Koji; Okuda, Sayo; Watasaki, Masahiro; Izumi, Mitsuru

    2016-03-01

    For the past 10 years, we have studied high-temperature superconducting (HTS) bulk magnets for use in electromagnetic rotating machines. If the magnetic field effectively magnetizes the HTS bulk, then the size of the motor and generator can be reduced without a reduction in output. We showed that the melt-textured Gd-Ba-Cu-O HTS bulk effectively traps a high magnetic field using waveform control pulse magnetization (WCPM). WCPM makes it possible to generate any pulsed magnetic field waveform by appropriately changing the duty ratio of the pulse width modulation. By chopping so that the pulsed magnetic field has a period of about 1ms, the WCPM technology enables active control of the rise time and suppresses magnetic flux motion that decreases magnetization efficiency. This method is also useful for any HTS bulk magnet, and the high magnetic flux density is trapped in the HTS bulk by a single pulse magnetic field. We developed a magnetizer that has a feedback system from the penetrated magnetic flux density to realize WCPM. In this research, using only a single pulse magnetic field of WCPM method at 77K, an HTS bulk with a 45mm diameter and 19mm thickness trapped a maximum magnetic field of 1.63T, which is more than 90% of the trapped magnetic flux density by FC magnetization. This result suggests that the pulse magnetizing method can replace the conventional field-cooled method and promote the practical use of HTS magnets for electromagnetic power applications.

  2. Upgrade of SULTAN/EDIPO for HTS Cable Test

    NASA Astrophysics Data System (ADS)

    Wesche, R.; Bruzzone, P.; Uglietti, D.; Bykovsky, N.; Lewandowska, M.

    CRPP hosts two unique conductor test facilities SULTAN (SUpraLeiter TestANlage) and EDIPO (European DIPOle). They allow the test of high current superconductors in high magnetic fields (SULTAN 11 T, EDIPO 12.5 T). In both facilities sample currents up to 100 kA can be supplied by means of a NbTi transformer. Presently the facilities are upgraded for the test of high current high-temperature superconductor (HTS) samples. For HTS conductor testing at temperatures between 20 and 50 K, the heat flux between the HTS sample under test and the NbTi transformer needs to be limited to around 10 W per conductor leg by means of an HTS adapter connecting them. The second required upgrade is the supply of intermediate temperature helium (20-50 K) to the HTS test conductor. It is mandatory that the helium gas coming from the HTS conductor under test can be returned to the cryoplant as cold gas (T < 20 K). To reach this goal a tube-in-tube heat exchanger has been manufactured in which 4.5 K helium coming from the cryoplant is in counter flow with the warm gas leaving the HTS test conductor.

  3. Efficient growth of HTS films with volatile elements

    DOEpatents

    Siegal, M.P.; Overmyer, D.L.; Dominguez, F.

    1998-12-22

    A system is disclosed for applying a volatile element-HTS layer, such as Tl-HTS, to a substrate in a multiple zone furnace, said method includes heating at higher temperature, in one zone of the furnace, a substrate and adjacent first source of Tl-HTS material, to sublimate Tl-oxide from the source to the substrate; and heating at lower temperature, in a separate zone of the furnace, a second source of Tl-oxide to replenish the first source of Tl-oxide from the second source. 3 figs.

  4. Efficient growth of HTS films with volatile elements

    DOEpatents

    Siegal, Michael P.; Overmyer, Donald L.; Dominguez, Frank

    1998-01-01

    A system for applying a volatile element-HTS layer, such as Tl-HTS, to a substrate in a multiple zone furnace, said method includes heating at higher temperature, in one zone of the furnace, a substrate and adjacent first source of Tl-HTS material, to sublimate Tl-oxide from the source to the substrate; and heating at lower temperature, in a separate zone of the furnace, a second source of Tl-oxide to replenish the first source of Tl-oxide from the second source.

  5. Experimental Manufacture and Performance Evaluation of Linear Switched Reluctance Motor with HTS Excitation Windings

    NASA Astrophysics Data System (ADS)

    Hirayama, Tadashi; Oto, Satoshi; Higashijima, Atsushi; Kawabata, Shuma

    This paper presents an experimental manufacture and performance evaluation of prototype linear switched reluctance motor with HTS excitation windings (HTS-LSRM). The Ag-alloy sheathed Bi-2223 tapes are used for HTS coils. We first present a structure of the prototype HTS-LSRM. Next, current-carrying properties of the HTS coils are measured. Furthermore, current and voltage waveforms are measured and we evaluation a control performance of the current and voltage.

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

    SciTech Connect

    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.

    2009-12-16

    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.

  7. Visually guided eye growth in the squid.

    PubMed

    Turnbull, Philip R K; Backhouse, Simon; Phillips, John R

    2015-09-21

    Eyes with refractive error have reduced visual acuity and are rarely found in the wild. Vertebrate eyes possess a visually guided emmetropisation process within the retina which detects the sign of defocus, and regulates eye growth to align the retina at the focal plane of the eye's optical components to avoid the development of refractive error, such as myopia, an increasing problem in humans. However, the vertebrate retina is complex, and it is not known which of the many classes of retinal neurons are involved. We investigated whether the camera-type eye of an invertebrate, the squid, displays visually guided emmetropisation, despite squid eyes having a simple photoreceptor-only retina. We exploited inherent longitudinal chromatic aberration (LCA) to create disparate focal lengths within squid eyes. We found that squid raised under orange light had proportionately longer eyes and more myopic refractions than those raised under blue light, and when switched between wavelengths, eye size and refractive status changed appropriately within a few days. This demonstrates that squid eye growth is visually guided, and suggests that the complex retina seen in vertebrates may not be required for emmetropisation. PMID:26394098

  8. Squid – a simple bioinformatics grid

    PubMed Central

    Carvalho, Paulo C; Glória, Rafael V; de Miranda, Antonio B; Degrave, Wim M

    2005-01-01

    Background BLAST is a widely used genetic research tool for analysis of similarity between nucleotide and protein sequences. This paper presents a software application entitled "Squid" that makes use of grid technology. The current version, as an example, is configured for BLAST applications, but adaptation for other computing intensive repetitive tasks can be easily accomplished in the open source version. This enables the allocation of remote resources to perform distributed computing, making large BLAST queries viable without the need of high-end computers. Results Most distributed computing / grid solutions have complex installation procedures requiring a computer specialist, or have limitations regarding operating systems. Squid is a multi-platform, open-source program designed to "keep things simple" while offering high-end computing power for large scale applications. Squid also has an efficient fault tolerance and crash recovery system against data loss, being able to re-route jobs upon node failure and recover even if the master machine fails. Our results show that a Squid application, working with N nodes and proper network resources, can process BLAST queries almost N times faster than if working with only one computer. Conclusion Squid offers high-end computing, even for the non-specialist, and is freely available at the project web site. Its open-source and binary Windows distributions contain detailed instructions and a "plug-n-play" instalation containing a pre-configured example. PMID:16078998

  9. Flux modulation scheme for direct current SQUID readout revisited

    NASA Astrophysics Data System (ADS)

    Hong, Tao; Wang, Hai; Zhang, Yi; Krause, Hans-Joachim; Braginski, Alex I.; Xie, Xiaoming; Offenhäusser, Andreas; Jiang, Mianheng

    2016-02-01

    The flux modulation scheme (FMS) is the standard readout technique of dc SQUIDs, where a step-up transformer links the SQUID to the preamplifier. The transformer's primary winding shunts the SQUID via a large capacitor while the secondary winding connects it to the preamplifier. A modulation flux having a frequency of typically 100 kHz generates an ac voltage across the SQUID, stepped up by the transformer. The SQUID with FMS is customarily operated in the current bias mode, because a constant dc bias current flows only through the SQUID due to the capacitor isolation. With FMS, however, the transformer ac shunts the SQUID so that in reality the operating mode is neither purely current-biased nor voltage-biased but rather nominal current-biased or "mixed biased." Our objective is to experimentally investigate the consequences of ac shunting of the dc SQUID in FMS and the transformer's transfer characteristics. For different shunt values we measure the change in the SQUID bias current due to the ac shunt using another SQUID in the two-stage readout scheme, and simultaneously monitor the SQUID output voltage signal. We then explain our measurements by a simplified graphic analysis of SQUID intrinsic current-voltage (I-V) characteristics. Since the total current flowing through the SQUID is not constant due to the shunting effect of the transformer, the amplitude of SQUID flux-to-voltage characteristics V(Φ) is less as compared to the direct readout scheme (DRS). Furthermore, we analyze and compare V(Φ) obtained by DRS and FMS. We show that in FMS, the transfer characteristics of the SQUID circuit also depend on the isolation capacitance and the dynamic resistance of the SQUID.

  10. Prospects of long-distance HTS DC power transmission systems

    NASA Astrophysics Data System (ADS)

    Romashov, M. A.; Sytnikov, V. E.; Shakarian, Y. G.; Ivanov, Y. V.

    2014-05-01

    Continual improvement of technologies for the safe use of power resources is a key to sustainable development of a human society. In particular, high-temperature superconductivity (HTS) should be used to meet the growing needs of the electric-power industry. It is known that HTS power cables allow us to increase the level of transmitted energy to several GW at voltage of 66-110 kV. HTS power cables of a coaxial design are almost ideal non-polluting system shielding electromagnetic field. In the present work we have tried to analyze various configurations of HTS power transmission systems, estimate the cable transmission capacitance depending on distance, and characterize reliability and efficiency of the systems.

  11. Rotor compound concept for designing an industrial HTS synchronous motor

    NASA Astrophysics Data System (ADS)

    Kashani, M.; Hosseina, M.; Sarrafan, K.; Darabi, A.

    2013-06-01

    Recently, producing power with smaller amount of losses become as a goal in our daily life. Today, large amount of energy waste in power networks all around the world. The main reason is “resistive electric equipments” of power networks. Since early 1980s, simultaneous with the development of high temperature superconductive (HTS) technology, superconductors gently attracted the mankind attentions. Using superconductive equipments instead of conventional resistive ones are result in salient electric loss reduction in power systems. Especially to reduce losses in power networks superconductive industrial rotating machines can potentially perform a significant role. In early recent century, first generation of HTS rotating machines was born. But unfortunately they have long way to penetrate the commercial markets yet. In HTS rotating machines the conventional copper made windings are replaced with the HTS superconductors. In this paper an industrial HTS synchronous motor with YBCO coated conductor field windings was designed. As a new approach, model was equipped with a compound rotor that includes both magnetic and non-magnetic materials. So, large amount of heavy iron made part was replaced by light non-magnetic material such as G-10 fiberglass. Furthermore, in this structure iron loss in rotor could be reduced to its lowest value. Also less weight and more air gap energy density were the additional advantages. Regarding zero electric loss production in field windings and less iron loss in rotor construction, this model potentially is more effective than the other iron made HTS motors.

  12. HTS thin films: Passive microwave components and systems integration issues

    SciTech Connect

    Miranda, F.A.; Chorey, C.M.; Bhasin, K.B.

    1994-12-31

    The excellent microwave properties of the High-Temperature-Superconductors (HTS) have been amply demonstrated in the laboratory by techniques such as resonant cavity, power transmission and microstrip resonator measurements. The low loss and high Q passive structures made possible with HTS, present attractive options for applications in commercial, military and space-based systems. However, to readily insert HTS into these systems improvement is needed in such areas as repeatability in the deposition and processing of the HTS films, metal-contact formation, wire bonding, and overall film endurance to fabrication and assembly procedures. In this paper we present data compiled in our lab which illustrate many of the problems associated with these issues. Much of this data were obtained in the production of a space qualified hybrid receiver-downconverter module for the Naval Research Laboratory`s High Temperature Superconductivity Space Experiment II (HTSSE-II). Examples of variations observed in starting films and finished circuits will be presented. It is shown that under identical processing the properties of the HTS films can degrade to varying extents. Finally, we present data on ohmic contacts and factors affecting their adhesion to HTS films, strength of wire bonds made to such contacts, and aging effects.

  13. SQUID method of lung contamination testing

    NASA Astrophysics Data System (ADS)

    Martinická, F.; Šimáček, I.; Jurdák, P.; Cigáň, A.; Maňka, J.

    2006-03-01

    We are reporting on the development of a SQUID magnetometric method of ferromagnetic dust quantification in the human lungs. In order to solve this problem we utilize a forward method of magnetized ferromagnetic particle (dipole) distribution 3D modeling in human lung torso and in an arc welder's lungs. We also solve the inverse problem, by which the amount of dust in the lungs is estimated using the results of the remanent magnetic induction Br measurement upon the human chest. We state the formula for SQUID measured output voltage U to Br conversion for the second order gradiometer, which is in a highly dipole position and density dependent. We utilize a low-Tc second order rf SQUID gradiometer with the sensitivity of 10-14 T in the unit frequency range.

  14. A Three-Channel DC SQUID System Using Time-Domain Multiplexing

    NASA Astrophysics Data System (ADS)

    Korn, Matthias; Mueck, Michael; Mugford, Chas; Kycia, Jan

    2004-03-01

    Conventional multichannel SQUID systems require SQUID readout electronics for each channel, as well as many wires connecting the individual SQUIDs and feedback coils to the room temperature electronics. We have studied a time domain multiplexed readout scheme which requires only a single SQUID readout which is successively switched between all SQUIDs. By connecting all SQUIDs and all feedback coils in series, the system requires only a few wires between SQUIDs and room temperature readout.

  15. Development of HTS magnets for application

    NASA Astrophysics Data System (ADS)

    Hatanaka, Kichiji; Fukuda, Mitsuhiro; Yorita, Tetsuhiko; Ueda, Hiroshi; Yasuda, Yuusuke; Kamakura, Keita; Morita, Yoshiya; Yamane, Hiroyoshi; Kawaguchi, Takeo

    2014-09-01

    We have been developing magnets utilizing high-temperature superconducting (HTS) wires for this decade. We built three model magnets, a mirror coil for an ECR ion source, a set of coils for a scanning magnet and a super-ferric dipole magnet to generate magnetic field of 3 T. They were excited with AC/pulse currents as well as DC currents. Recently we fabricated a cylindrical magnet for a practical use which polarizes ultracold neutrons (UCN). It consists of 10 double pancakes and the field strength at the center is higher than 3.5 T which is required to fully polarize 210 neV neutrons. It was successfully cooled and excited. The magnet was used to polarized UCN generated by the RCNP-KEK superthermal UCN source, One dipole magnet has been manufactured which is used as a switching magnet after the RCNP ring cyclotron and is excited by pulse currents. It becomes possible to deliver beams to two experimental halls by time sharing. Their designs and performances are presented in the talk.

  16. Optimization of Our SC HTS Reluctance Motor

    NASA Astrophysics Data System (ADS)

    Oswald, B.; Best, K.-J.; Setzer, M.; Söll, M.; Gawalek, W.; Gutt, A.; Kovalev, L.; Fisher, L.; Krabbes, G.; Freyhardt, H. C.

    2004-06-01

    Since several years we have successfully designed, built and tested at 77K several reluctance motors. YBCO bulk material has been incorporated into the rotor. Our latest results, based on the old design, will be published within the proceedings of the 8th VDI-Status-Seminar. The range of mechanical output power achieved is up to about 200 kW. All these motors have shown that a significant step in performance is obtained by using HTS bulk elements in the rotor, compared to the data of these test motors without superconductors. However, by now the motor parameters have been limited to certain values. In order to optimize this type of motor and to achieve increased output power and power density we have modified the design with several respects. This includes properties of the superconductor (critical current density raised by about 20%), the use of special soft magnetic material in the stator (increased saturation polarization), modified cut of the laminations (optimized for application at 77 K), and new geometry of the motor dimensions aimed at extremely high dynamics in order to adapt this motor to some special applications. With our present paper we present the results of this optimization which have brought the expected improvements and which are in excellent accordance with theory.

  17. 4.2K Cryocooled Scanning SQUID Microscope

    NASA Astrophysics Data System (ADS)

    Kwon, S. P.; Knauss, L.; Lettsome, N.; Cawthorne, A.; Lobb, C. J.; Wellstood, F. C.

    2003-03-01

    We have assembled a scanning SQUID microscope using a Nb SQUID and a cryocooler. The Nb SQUID is contained within a vacuum jacket while material being scanned is at room temperature and normal atmospheric pressure. A 25 micron thick sapphire window separates the SQUID in vacuum from the scanned material. The Nb DC SQUID, fabricated by Hypres Inc., has an inner dimension of 10 microns by 10 microns and the Josephson Junctions are resistively shunted. Cooling is provided by a Pulse Tube Cryocooler from Cryomech Inc. Temperatures as low as 3.8 K have been obtained while operating the SQUID microscope. Due to radiation heating, the temperature of the SQUID has been estimated to be 1.0 K to 1.5 K higher than sensor values. Flux-Locked-Loop electronics are used to take magnetic field data. Preliminary measurements of the flux noise indicated resolution to better than 10 micro Flux Quantum for one second averaging time.

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

    NASA Astrophysics Data System (ADS)

    Tabatabaei, Mahdi; Bahadır Olcay, Ali; Gokçen, Gökhan; Heperkan, Hasan A.

    2015-05-01

    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.

  19. Onshore-offshore movement of jumbo squid (Dosidicus gigas) on the continental shelf

    NASA Astrophysics Data System (ADS)

    Stewart, Julia S.; Gilly, William F.; Field, John C.; Payne, John C.

    2013-10-01

    Jumbo squid (Dosidicus gigas) have greatly extended their range in the California Current System, where they forage on a variety of ecologically and economically important species that inhabit both coastal and offshore mesopelagic regions. Swimming abilities and behavior are important factors in assessing the impacts of this range expansion, particularly in regard to foraging in conjunction with onshore-offshore movement over the continental shelf. Here we describe a study of horizontal movements by jumbo squid along and across the continental shelf off Washington, USA, using acoustic tags in association with the Census of Marine Life's Pacific Ocean Shelf Tracking Program (POST) receiver arrays. We detected frequent movements along the shelf break, movement onto the shelf at night, and no evidence of movement as a cohesive school. Our results demonstrate feasibility of using acoustic tags and arrays to document horizontal movements of jumbo squid along and across the continental shelf. This is important in order to determine how those movements overlap with those of other ecologically and commercially important fish species.

  20. Multichannel SQUID systems for brain research

    SciTech Connect

    Ahonen, A.I.; Hamalainen, M.S.; Kajola, M.J.; Knuutila, J.E.F.; Lounasmaa, O.V.; Simola, J.T.; Vilkman, V.A. . Low Temperature Lab.); Tesche, C.D. . Thomas J. Watson Research Center)

    1991-03-01

    This paper reviews basis principles of magnetoencephalography (MEG) and neuromagnetic instrumentation. The authors' 24-channel system, based on planar gradiometer coils and dc-SQUIDs, is then described. Finally, recent MEG-experiments on human somatotopy and focal epilepsy, carried out in the authors' laboratory, are presented.

  1. One Period of Exploration with the Squid.

    ERIC Educational Resources Information Center

    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)

  2. Squid Dissection: From Pen to Ink.

    ERIC Educational Resources Information Center

    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)

  3. High Resolution LTS-SQUID Microscopes

    NASA Astrophysics Data System (ADS)

    Baudenbacher, Franz; Peters, Nicholas; Wikswo, John

    2000-03-01

    We have developed a scanning superconducting quantum interference device (SQUID) microscope for imaging magnetic fields of room-temperature samples with sub-millimeter resolution. In our design, hand wound niobium pickup coils were coupled to commercially available low-temperature SQUID sensors. The SQUID sensor and the pickup coil are in the vacuum space of the cryostat separated typically less than 50μm by a thin sapphire window from the room-temperature sample. A computerized non-magnetic scanning stage with sub-micron resolution in combination with a tripod leveling system allows samples to be scanned within 10μm of the sapphire window. For a 20-turn 500μm diameter pickup coil, we achieved a field sensitivity of 350fT\\cdotHz-1/2 for frequencies above 1 Hz, and 1pT\\cdotHz-1/2 for a 10-turn 250mm coil. The SQUID microscope was used to image the distribution of time-dependent stimulus and action currents in anisotropic cardiac tissue, the remanent magnetization of the Martian meteorite ALH84001 during thermal demagnetisation, and the magnetic susceptibility of biogenic magnetite in the beak of homing pigeons.

  4. Modelling ac ripple currents in HTS coated conductors

    NASA Astrophysics Data System (ADS)

    Xu, Zhihan; Grilli, Francesco

    2015-10-01

    Dc transmission using high temperature superconducting (HTS) coated conductors (CCs) offers a promising solution to the globally growing demand for effective, reliable and economic transmission of green energy up to the gigawatt level over very long distances. The credible estimation of the losses and thereby the heat dissipation involved, where ac ripples (introduced in rectification/ac-dc conversion) are viewed as a potential source of notable contribution, is highly essential for the rational design of practical HTS dc transmission cables and corresponding cryogenic systems to fulfil this demand. Here we report a targeted modelling study into the ac losses in a HTS CC subject to dc and ac ripple currents simultaneously, by solving Maxwell’s equations using the finite element method (FEM) in the commercial software package COMSOL. It is observed that the instantaneous loss exhibits only one peak per cycle in the HTS CC subject to sinusoidal ripples, given that the amplitude of the ac ripples is smaller than approximately 20% of that of the dc current. This is a distinct contrast to the usual observation of two peaks per cycle in a HTS CC subject to ac currents only. The unique mechanism is also revealed, which is directly associated with the finding that, around any local minima of the applied ac ripples, the critical state of -J c is never reached at the edges of the HTS CC, as it should be according to the Bean model. When running further into the longer term, it is discovered that the ac ripple loss of the HTS CC in full-wave rectification decays monotonically, at a speed which is found to be insensitive to the frequency of the applied ripples within our targeted situations, to a relatively low level of approximately 1.38 × 10-4 W m-1 in around 1.7 s. Comparison between this level and other typical loss contributions in a HTS dc cable implies that ac ripple currents in HTS CCs should only be considered as a minor source of dissipation in superconducting dc

  5. Superconducting Nanobridge SQUID Magnetometers for Spin Sensing

    NASA Astrophysics Data System (ADS)

    Antler, Natania

    As the cutting edge of science and technology pushes towards smaller length scales, sensing technologies with nanoscale precision become increasingly important. In this thesis I will discuss the optimization and application of a 3D nanobridge SQUID magnetometer for studying solid state spin systems, in particular for sensing impurity spins in diamond. Solid state spins have proposed applications in memory and computation for both classical and quantum computing. Isolated spins typically have longer coherence times, making them attractive qubit candidates, but necessitating the development of very sensitive detectors for readout. This 3D nanobridge SQUID combines the exquisite spatial sensitivity of a traditional nanoSQUID with a large non-linearity on par with a tunnel junction SQUID. This allows us to build a highly sensitive magnetometer which can act as both an efficient flux transducer as well as a nearly quantum limited lumped Josephson Parametric Amplifier. We show that the device has a minimum flux noise of 17 +/- 0.9 nphi0/Hz1/2 with only a factor of ˜2.5 increase in flux noise up to 61 mT. A second generation device with a smaller capacitor achieves field tolerance up to 75 mT. The maximal bandwidth values range from 25-40 MHz in the parametric amplification regime to 70 MHz in the linear regime. This combination of large bandwidth, low flux noise, large flux coupling and field tolerance make this sensor a promising candidate for near-single-spin dynamics measurements. In the last part of this thesis we begin to demonstrate the utility of a nanobridge SQUID magnetometer for characterizing spin systems in the solid state. We use the magnetometer to measure the decay characteristics of P1 centers in diamond. We find that the spin-lattice relaxation time varies with temperature, with an order of magnitude decrease in the decay time between 25 mK and 370 mK.

  6. Toward early cancer detection using superparamagnetic relaxometry in a SQUID-based ULF-MRI system

    NASA Astrophysics Data System (ADS)

    Magnelind, P. E.; Kim, Y. J.; Matlashov, A. N.; Newman, S. G.; Volegov, P. L.; Espy, M. A.

    2014-04-01

    To detect cancer at a very early state it is essential to detect a very small quantity of cancerous cells. One very sensitive method relies on targeting the cancer cells using antibody labeled single-core magnetic nanoparticles and detecting the relaxation of the magnetization using instruments based on superconducting quantum interference devices (SQUIDs). However, the localization suffers from inverse-problem issues similar to those found in magnetoencephalography. On the other hand, the same magnetic nanoparticles can also work as contrast agents for magnetic resonance imaging. Through the combination of superparamagnetic relaxometry and ultra-low field magnetic resonance imaging (ULF MRI), in one and the same instrument, the accuracy of the magnetic moment localization can be enhanced and anatomical information can also be obtained. Results on superparamagnetic relaxometry and the dipole localization accuracy in our seven-channel low-Tc SQUID-gradiometer array are reported.

  7. Low-noise ultra-high-speed dc SQUID readout electronics

    NASA Astrophysics Data System (ADS)

    Drung, Dietmar; Hinnrichs, Colmar; Barthelmess, Henry-Jobes

    2006-05-01

    User-friendly ultra-high-speed readout electronics for dc superconducting quantum interference devices (SQUIDs) are presented. To maximize the system bandwidth, the SQUID is directly read out without flux modulation. A composite preamplifier is used consisting of a slow dc amplifier in parallel with a fast ac amplifier. In this way, excellent dc precision and a high amplifier bandwidth of 50 MHz are achieved, simultaneously. A virtual 50 Ω amplifier input resistance with negligible excess noise is realized by active shunting, i.e., by applying feedback from preamplifier output to input via a high resistance. The white voltage and current noise levels are 0.33 nV Hz-1 and 2.6 pA Hz-1/2, respectively. The electronics is fully computer controlled via a microcontroller integrated into the flux-locked loop (FLL) board. Easy-to-use software makes the various electronic settings accessible. A wide bias voltage range of 1.3 mV enables the readout of series SQUID arrays. Furthermore, additional current sources allow the operation of two-stage SQUIDs or transition edge sensors. The electronics was tested using various SQUIDs with input inductances between 30 nH and 1.5 µH. Typically, the maximum FLL bandwidth was 20 MHz, which is close to the theoretical limit given by transmission line delay within the FLL. Slew rates of up to 4.6 Φ0 µs-1 were achieved with series SQUID arrays. Current noise levels as low as 0.47 pA Hz-1/2 and coupled energy sensitivities between 90 h and 500 h were measured at 4.2 K, where h is the Planck constant. The noise did not degrade when the system bandwidth was increased to the maximum value of about 20 MHz. With a two-stage set-up, intrinsic white energy sensitivities of 30 h and 2.3 h were measured at 4.2 and 0.3 K, respectively.

  8. Heat Transfer Experiments and Analysis of a Simulated HTS

    SciTech Connect

    Demko, Jonathan A; Duckworth, Robert C; Gouge, Michael J; Knoll, David

    2010-01-01

    Long-length high temperature superconducting (HTS) cable projects, over 1 km, are being designed that are cooled by flowing liquid nitrogen. The compact counter-flow cooling arrangement which has the supply and return stream in a single cryostat offers several advantages including smallest space requirement, least heat load, and reduced cost since a return cryostat is not required. One issue in long length HTS cable systems is the magnitude of the heat transfer radially through the cable. It is extremely difficult to instrument an HTS cable in service on the grid with the needed thermometry because of the issues associated with installing thermometers on high voltage components. A 5-meter long test system has been built that simulates a counter-flow cooled, HTS cable using a heated tube to simulate the cable. Measurements of the temperatures in the flow stream and on the tube wall are presented and compared to analysis. These data can be used to benchmark different HTS cable heat transfer and fluid flow analysis approaches.

  9. HTS power lead testing at the Fermilab magnet test facility

    SciTech Connect

    Rabehl, R.; Carcagno, R.; Feher, S.; Huang, Y.; Orris, D.; Pischalnikov, Y.; Sylvester, C.; Tartaglia, M.; /Fermilab

    2005-08-01

    The Fermilab Magnet Test Facility has tested high-temperature superconductor (HTS) power leads for cryogenic feed boxes to be placed at the Large Hadron Collider (LHC) interaction regions and at the new BTeV C0 interaction region of the Fermilab Tevatron. A new test facility was designed and operated, successfully testing 20 pairs of HTS power leads for the LHC and 2 pairs of HTS power leads for the BTeV experiment. This paper describes the design and operation of the cryogenics, process controls, data acquisition, and quench management systems. Results from the facility commissioning are included, as is the performance of a new insulation method to prevent frost accumulation on the warm ends of the power leads.

  10. Test Results for a 25 Meter Prototype Fault Current Limiting Hts Cable for Project Hydra

    NASA Astrophysics Data System (ADS)

    Rey, C. M.; Duckworth, R. C.; Demko, J. A.; Ellis, A.; James, D. R.; Gouge, M. J.; Tuncer, E.

    2010-04-01

    The Oak Ridge National Laboratory (ORNL) has tested a 25-m long prototype High Temperature Superconducting (HTS) cable with inherent Fault-Current Limiting (FCL) capability at its HTS cable test facility. The HTS-FCL cable and terminations were designed and fabricated by Ultera, which is a joint venture between Southwire and nkt cables. System integration and HTS wire were provided by American Superconductor Corporation who was the overall team leader of the project. The ultimate goal of the 25-m HTS-FCL cable test program was to verify the design and ensure the operational integrity for the eventual installation of a ˜200-m fully functional HTS-FCL cable in the Consolidated Edison electric grid located in downtown New York City. The 25-m HTS-FCL cable consisted of a three-phase (3-Φ) HTS Triax™ design with a cold dielectric between the phases. The HTS-FCL cable had an operational voltage of 13.8 kV phase-to-phase (7967 V phase-to-ground) and an operating current of 4000 Arms per phase, which is the highest operating current to date of any HTS cable. The 25-m HTS-FCL cable was subjected to a series of cryogenic and electrical tests. Test results from the 25-m HTS-FCL cable are presented and discussed.

  11. Study of HTS Wires at High Magnetic Fields

    SciTech Connect

    Turrioni, D.; Barzi, E.; Lamm, M.J.; Yamada, R.; Zlobin, A.V.; Kikuchi, A.; /Fermilab

    2009-01-01

    Fermilab is working on the development of high field magnet systems for ionization cooling of muon beams. The use of high temperature superconducting (HTS) materials is being considered for these magnets using Helium refrigeration. Critical current (I{sub c}) measurements of HTS conductors were performed at FNAL and at NIMS up to 28 T under magnetic fields at zero to 90 degree with respect to the sample face. A description of the test setups and results on a BSCCO-2223 tape and second generation (2G) coated conductors are presented.

  12. DEVELOPMENT OF HTS CONDUCTORS FOR ELECTRIC POWER APPLICATIONS

    SciTech Connect

    Goyal, A.; Rupich, M.

    2012-10-23

    Second generation (2G) technologies to fabricate high-performance superconducting wires developed at the Oak Ridge National Laboratory (ORNL) were transferred to American Superconductor via this CRADA. In addition, co-development of technologies for over a decade was done to enable fabrication of commercial high-temperature superconducting (HTS) wires with high performance. The massive success of this CRADA has allowed American Superconductor Corporation (AMSC) to become a global leader in the fabrication of HTS wire and the technology is fully based on the Rolling Assisted Biaxially Textured Substrates (RABiTS) technology invented and developed at ORNL.

  13. Review of activities in USA on HTS materials

    SciTech Connect

    Peterson, D.E.

    1995-02-01

    Rapid progress in attaining practical applications of High Temperature Superconductors (HTS) has been made since the discovery of these new materials. Many critical parameters influencing HTS powder synthesis and wire processing have been identified through a combination of fundamental exploration and applied research. The complexity of these novel materials with regard to phase behavior and physical properties has become evident as a result of these careful studies. Achieving optimal mechanical and superconducting properties in wires and tapes will require further understanding and synergy among several different technical disciplines. Highlights of efforts towards producing practical superconductors for electric power applications based on rare earth-, bismuth-, and thallium-based systems are reviewed.

  14. Quench detection system for twin coils HTS SMES

    NASA Astrophysics Data System (ADS)

    Badel, A.; Tixador, P.; Simiand, G.; Exchaw, O.

    2010-10-01

    The quench detection and protection system is a critical element in superconducting magnets. After a short summary of the quench detection and protection issues in HTS magnets, an original detection system is presented. The main feature of this system is an active protection of the detection electronics during the discharges, making it possible to use standard electronics even if the discharge voltage is very high. The design of the detection system is therefore easier and it can be made very sensitive. An implementation example is presented for a twin coil HTS SMES prototype, showing the improvements when compared to classical detection systems during operation.

  15. Development of a 600 kJ HTS SMES

    NASA Astrophysics Data System (ADS)

    Seong, K. C.; Kim, H. J.; Kim, S. H.; Sim, K. D.; Sohn, M. H.; Lee, E. Y.; Park, S. J.; Hahn, S. Y.; Park, M. W.

    2008-09-01

    This paper describes an overview of development on a 600 kJ high-temperature superconducting magnetic energy storage (HTS SMES). Our final goal will be the commercialization of MJ class HTS SMES system for the increase of power quality within 5 years. Hence, for this purpose, we have developed the research and development in 3 years. The purpose of this research is to develop a pilot system, which can protect the sensitivity loads from a momentary power interruption or a voltage sag.

  16. A method for simulating a flux-locked DC SQUID

    NASA Technical Reports Server (NTRS)

    Gutt, G. M.; Kasdin, N. J.; Condron, M. R., II; Muhlfelder, B.; Lockhart, J. M.; Cromar, M. W.

    1993-01-01

    The authors describe a computationally efficient and accurate method for simulating a dc SQUID's V-Phi (voltage-flux) and I-V characteristics which has proven valuable in evaluating and improving various SQUID readout methods. The simulation of the SQUID is based on fitting of previously acquired data from either a real or a modeled device using the Fourier transform of the V-Phi curve. This method does not predict SQUID behavior, but rather is a way of replicating a known behavior efficiently with portability into various simulation programs such as SPICE. The authors discuss the methods used to simulate the SQUID and the flux-locking control electronics, and present specific examples of this approach. Results include an estimate of the slew rate and linearity of a simple flux-locked loop using a characterized dc SQUID.

  17. Multichannel applications of double relaxation oscillation SQUIDs

    NASA Astrophysics Data System (ADS)

    Lee, Yong-Ho; Kwon, Hyukchan; Kim, Jin-Mok; Park, Yong-Ki

    2001-12-01

    Double relaxation oscillation SQUIDs (DROSs) provided high flux-to-voltage transfers of larger than 1 mV Φ0-1 and simple flux-locked loop circuits were used for SQUID operation. We constructed two multichannel systems based on DROSs. The first system is a 40-channel planar gradiometer system consisting of integrated first-order pickup coils. average noise level of the 40 channels is 1 fT cm-1 Hz-1/2 at 100 Hz, corresponding to a field noise of 4 fT Hz-1/2, operating inside a magnetically shielded room. The second one is a 37-channel magnetometer system with 37 integrated magnetometers distributed on a spherical surface and measures field component normal to the head surface. The average noise of the magnetometers is 3 fT Hz-1/2 at 100 Hz. The two systems were applied to measure neuromagnetic fields.

  18. Practical SQUID Instrument for Nondestructive Testing

    NASA Technical Reports Server (NTRS)

    Tralshawala, N.; Claycomb, J. R.; Miller, John H., Jr.

    1997-01-01

    We report on the development of a scanning eddy-current imaging system designed to detect deep subsurface flaws in conducting materials. A high transition temperature (high-T c) superconducting quantum interference device (SQUID) magnetometer is employed to provide the required sensitivity at low frequencies, while a combination of small cylindrical high-Tc superconducting and A-metal shields enable the instrument to be scanned in a magnetically noisy environment, rather than the object under test. The shields are arranged to prevent unwanted excitation and ambient noise fields from reaching the SQUID, and to enhance spatial resolution and minimize undesirable edge effects. Thus far, the instrument has successfully detected cracks and pits through 10 layers of aluminum, with a combined thickness of 5 cm at room temperature.

  19. Low Temperature SQUID for NDE Applications

    NASA Technical Reports Server (NTRS)

    Wincheski, Buzz (Technical Monitor); Selim, Raouf

    2003-01-01

    We have developed a low temperature SuperConducting Quantum Interference Device - SQUID measurement system for detection of defects deep under the surface of aluminum structures using eddy current techniques. The system uses a two dimensional planar inducer with two different excitation frequencies to induce a current in the sample. We have developed a data analysis software program that enabled us to distinguish between round defects (holes), straight defects (slots) and slots close to holes simulating cracks starting from rivets in aluminum structures. We were able to detect defects that are 8mm below the surface. We have also measured the change in phase of the detected signal as a function of depth of the defect. This relationship can be used to determine the depth of hidden flaws. Using this analysis software with the high temperature SQUID system at NASA Langley we were able to detect slots close to holes in layered aluminum sample.

  20. Supersensitive SQUID/magnetostrictor detecting system

    SciTech Connect

    Golovashkin, Aleksander I; Zherikhina, L N; Tskhovrebov, Andrei M; Izmailov, G N

    2012-12-31

    It is shown that using the state-of-the-art quantum interferometer (SQUID) with the resolution 10{sup -6} {Phi}{sub 0} Hz{sup -1/2} = 2.07 Multiplication-Sign 10{sup -21} Wb Hz{sup -1/2}, coupled to a magnetostrictor, playing the role of tensomagnetic transducer, it is possible to construct a system for detecting pressure variations with the ultimate sensitivity of 10{sup -13} Pa Hz{sup -1/2} and for measuring specific elongation with the sensitivity of 10{sup -24} Hz{sup -1/2}. The analysis of physical grounds of the inverse magnetostriction effect demonstrates concrete ways to essentially higher efficiency of tensomagnetic conversion. The estimates performed demonstrate the possibility of using the SQUID/magnetostrictor system as a detector of gravitational waves. Other possibilities of using this system for solving both fundamental and applied problems are also considered. (experimental techniques)

  1. Practical SQUID instrument for nondestructive testing

    SciTech Connect

    Tralshawala, N.; Claycomb, J.R.; Miller, J.H. Jr.

    1997-09-01

    We report on the development of a scanning eddy-current imaging system designed to detect deep subsurface flaws in conducting materials. A high transition temperature (high-T{sub c}) superconducting quantum interference device (SQUID) magnetometer is employed to provide the required sensitivity at low frequencies, while a combination of small cylindrical high-T{sub c} superconducting and {mu}-metal shields enable the instrument to be scanned in a magnetically noisy environment, rather than the object under test. The shields are arranged to prevent unwanted excitation and ambient noise fields from reaching the SQUID, and to enhance spatial resolution and minimize undesirable edge effects. Thus far, the instrument has successfully detected cracks and pits through 10 layers of aluminum, with a combined thickness of 5 cm at room temperature. {copyright} {ital 1997 American Institute of Physics.}

  2. Investigation of noise sources in SQUID electronics

    SciTech Connect

    Clem, T.R.; Goldstein, M.J.; Purpura, J.W.; Allen, L.H.; Claassen, J.H.; Gubser, D.U.; Wolf, S.A.

    1989-03-01

    The performance of SQUID-based electronics outside a laboratory-controlled environment may be degraded from that found in laboratory operation. Investigations on superconducting tubes, wires, and sheets have been conducted to identify contributions to such noise. Results have been obtained for bulk and thin film samples utilizing both the conventional low temperature materials, as well as the new high temperature oxide materials. Experiments have been conducted to quantify flux redistribution and flux motion in superconducting samples subjected to temperature changes, temperature gradients, and magnetic field gradients. These investigations have been conducted at magnetic fields typical of many SQUID applications, with field intensities much smaller than the critical values H/sub cl/. Penetration depth effects, flux pinning effects, and flux motion effects have been observed. The various types of experiments conducted along with specific results are described.

  3. Ceramic HTSC SQUID-based galvanometer

    SciTech Connect

    Uchaikin, S.V.; Hiep, L.H. )

    1992-06-01

    A highly sensitive galvanometer operating at liquid-nitrogen temperature for direct and low-frequency current measurements was developed on the basis of a HTSC SQUID. The direct-current sensitivity of the galvanometer is approximately 0.5 nA at an internal resistance of about 20 ohms. Its energy resolution in the white noise region is 2 x 10 exp 21 J/Hz. 11 refs.

  4. Digital filter design approach for SQUID gradiometers

    SciTech Connect

    Bruno, A.C.; Ribeiro, P.C.

    1988-04-15

    A review of the traditional method for designing gradiometers is made. A nonrecursive digital filter model for the gradiometer is presented, giving a new set of parameters for the gradiometer identification. Some designs are analyzed using the proposed set. As an example, a true differentiator is designed to be used as the SQUID input coil. It is shown that the differentiator has the same noise rejection as the conventional gradiometer but provides more signal sensitivity.

  5. Low Field Squid MRI Devices, Components and Methods

    NASA Technical Reports Server (NTRS)

    Penanen, Konstantin I. (Inventor); Eom, Byeong H. (Inventor); Hahn, Inseob (Inventor)

    2013-01-01

    Low field SQUID MRI devices, components and methods are disclosed. They include a portable low field (SQUID)-based MRI instrument and a portable low field SQUID-based MRI system to be operated under a bed where a subject is adapted to be located. Also disclosed is a method of distributing wires on an image encoding coil system adapted to be used with an NMR or MRI device for analyzing a sample or subject and a second order superconducting gradiometer adapted to be used with a low field SQUID-based MRI device as a sensing component for an MRI signal related to a subject or sample.

  6. Low field SQUID MRI devices, components and methods

    NASA Technical Reports Server (NTRS)

    Penanen, Konstantin I. (Inventor); Eom, Byeong H (Inventor); Hahn, Inseob (Inventor)

    2010-01-01

    Low field SQUID MRI devices, components and methods are disclosed. They include a portable low field (SQUID)-based MRI instrument and a portable low field SQUID-based MRI system to be operated under a bed where a subject is adapted to be located. Also disclosed is a method of distributing wires on an image encoding coil system adapted to be used with an NMR or MRI device for analyzing a sample or subject and a second order superconducting gradiometer adapted to be used with a low field SQUID-based MRI device as a sensing component for an MRI signal related to a subject or sample.

  7. Low Field Squid MRI Devices, Components and Methods

    NASA Technical Reports Server (NTRS)

    Penanen, Konstantin I. (Inventor); Eom, Byeong H. (Inventor); Hahn, Inseob (Inventor)

    2014-01-01

    Low field SQUID MRI devices, components and methods are disclosed. They include a portable low field (SQUID)-based MRI instrument and a portable low field SQUID-based MRI system to be operated under a bed where a subject is adapted to be located. Also disclosed is a method of distributing wires on an image encoding coil system adapted to be used with an NMR or MRI device for analyzing a sample or subject and a second order superconducting gradiometer adapted to be used with a low field SQUID-based MRI device as a sensing component for an MRI signal related to a subject or sample.

  8. Low field SQUID MRI devices, components and methods

    NASA Technical Reports Server (NTRS)

    Penanen, Konstantin I. (Inventor); Eom, Byeong H. (Inventor); Hahn, Inseob (Inventor)

    2011-01-01

    Low field SQUID MRI devices, components and methods are disclosed. They include a portable low field (SQUID)-based MRI instrument and a portable low field SQUID-based MRI system to be operated under a bed where a subject is adapted to be located. Also disclosed is a method of distributing wires on an image encoding coil system adapted to be used with an NMR or MRI device for analyzing a sample or subject and a second order superconducting gradiometer adapted to be used with a low field SQUID-based MRI device as a sensing component for an MRI signal related to a subject or sample.

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

    PubMed Central

    2013-01-01

    Background 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. Results 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. Conclusions 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. PMID:23418818

  10. A nanoscale SQUID operating at high magnetic fields

    SciTech Connect

    Lam, Simon K. H.; Clem, John R.; Yang, Wenrong

    2011-10-13

    A washer-free Nb nanoSQUID has been developed for measuring magnetization changes from nanoscale objects. The SQUID loop is etched into a 250 nm wide Au/Nb bilayer track and the diameter of the SQUID hole is {approx} 70 nm. In the presence of a magnetic field perpendicular to the plane of the SQUID, vortex penetration into the 250 nm wide track can be observed via the critical current-applied field characteristic and the value at which vortex first penetrates is consistent with the theoretical prediction. Upon removing the applied field, the penetrated vortices escape the track and the critical current at zero field is restored.

  11. A nanoscale SQUID operating at high magnetic fields

    SciTech Connect

    Lam, Simon K. H.; Clem, John R.; Yang, Wenrong

    2011-10-13

    A washer-free Nb nanoSQUID has been developed for measuring magnetization changes from nanoscale objects. The SQUID loop is etched into a 250 nm wide Au/Nb bilayer track and the diameter of the SQUID hole is ~ 70 nm. In the presence of a magnetic field perpendicular to the plane of the SQUID, vortex penetration into the 250 nm wide track can be observed via the critical current–applied field characteristic and the value at which vortex first penetrates is consistent with the theoretical prediction. Upon removing the applied field, the penetrated vortices escape the track and the critical current at zero field is restored.

  12. Transparency and Coherence in rf SQUID Metamaterials

    NASA Astrophysics Data System (ADS)

    Anlage, Steven; Trepanier, Melissa; Zhang, Daimeng

    We have developed active metamaterials capable of quickly tuning their electrical and magnetic responses over a wide frequency range. These metamaterials are based on superconducting elements to form low loss, physically and electrically small, highly tunable structures for fundamental studies of extraordinarily nonlinear media. The meta-atoms are rf superconducting quantum interference devices (SQUIDs) that incorporate the Josephson effect. RF SQUIDs have an inductance which is strongly tunable with dc and rf magnetic fields and currents. The rf SQUID metamaterial is a richly nonlinear effective medium introducing qualitatively new macroscopic quantum phenomena into the metamaterials community, namely magnetic flux quantization and the Josephson effect. The coherent oscillation of the meta-atoms is strongly sensitive to the environment and measurement conditions, and we have developed several strategies to improve the coherence experimentally by exploiting ideas from nonlinear dynamics. The metamaterials also display a unique form of transparency whose development can be manipulated through multiple parametric dependences. We discuss these qualitatively new metamaterial phenomena. This work is supported by the NSF-GOALI and OISE Programs through Grant No. ECCS-1158644 and the Center for Nanophysics and Advanced Materials (CNAM).

  13. Compartment-Specific Phosphorylation of Squid Neurofilaments.

    PubMed

    Grant, Philip; Pant, Harish C

    2016-01-01

    Studies of the giant axon and synapse of third-order neurons in the squid stellate ganglion have provided a vast literature on neuronal physiology and axon transport. Large neuronal size also lends itself to comparative biochemical studies of cell body versus axon. These have focused on the regulation of synthesis, assembly, posttranslational modification and function of neuronal cytoskeletal proteins (microtubules (MTs) and neurofilaments (NFs)), the predominant proteins in axoplasm. These contribute to axonal organization, stability, transport, and impulse transmission responsible for rapid contractions of mantle muscles underlying jet propulsion. Studies of vertebrate NFs have established an extensive literature on NF structure, organization, and function; studies of squid NFs, however, have made it possible to compare compartment-specific regulation of NF synthesis, assembly, and function in soma versus axoplasm. Since NFs contain over 100 eligible sites for phosphorylation by protein kinases, the compartment-specific patterns of phosphorylation have been a primary focus of biochemical studies. We have learned that NF phosphorylation is tightly compartmentalized; extensive phosphorylation occurs only in the axonal compartment in squid and in vertebrate neurons. This extensive phosphorylation plays a key role in organizing NFs, in association with microtubules (MTs), into a stable, dynamic functional lattice that supports axon growth, diameter, impulse transmission, and synaptic activity. To understand how cytoskeletal phosphorylation is topographically regulated, the kinases and phosphatases, bound to NFs isolated from cell bodies and axoplasm, have also been studied. PMID:26795486

  14. Numerical assessment of efficiency and control stability of an HTS synchronous motor

    NASA Astrophysics Data System (ADS)

    Xian, Wei; Yuan, Weijia; Coombs, T. A.

    2010-06-01

    A high temperature superconducting (HTS) permanent magnet synchronous motor (PMSM) is designed and developed in Cambridge University. It is expected to become cost competitive with the conventional PMSM owing to its high efficiency, high power density, high torque density, etc. The structure and parameters of HTS PMSM are detailed. Both AC losses by transport current and applied filed in stator armature winding of HTS PMSM are also analyzed. Computed and simulated results of the characteristics of the HTS PMSM and conventional PMSM are compared. The improvement on stability of direct torque control (DTC) on the HTS PMSM is estimated, and proved by simulation on Matlab/Simulink.

  15. A monolithic bolometer array suitable for FIRST

    NASA Technical Reports Server (NTRS)

    Bock, J. J.; LeDuc, H. G.; Lange, A. E.; Zmuidzinas, J.

    1997-01-01

    The development of arrays of infrared bolometers that are suitable for use in the Far Infrared and Submillimeter Telescope (FIRST) mission is reported. The array architecture is based on the silicon nitride micromesh bolometer currently baselined for use in the case of the Planck mission. This architecture allows each pixel to be efficiently coupled to one or both polarizations and to one or more spatial models of radiation. Micromesh structures are currently being developed, coupled with transistor-edge sensors and read out by a SQUID amplifier. If these devices are successful, then the relatively large cooling power available at 300 mK may enable a SQUID-based multiplexer to be integrated on the same wafer as the array, creating a monolithic, fully multiplexed, 2D array with relatively few connections to the sub-Kelvin stage.

  16. Large-scale HTS bulks for magnetic application

    NASA Astrophysics Data System (ADS)

    Werfel, Frank N.; Floegel-Delor, Uta; Riedel, Thomas; Goebel, Bernd; Rothfeld, Rolf; Schirrmeister, Peter; Wippich, Dieter

    2013-01-01

    ATZ Company has constructed about 130 HTS magnet systems using high-Tc bulk magnets. A key feature in scaling-up is the fabrication of YBCO melts textured multi-seeded large bulks with three to eight seeds. Except of levitation, magnetization, trapped field and hysteresis, we review system engineering parameters of HTS magnetic linear and rotational bearings like compactness, cryogenics, power density, efficiency and robust construction. We examine mobile compact YBCO bulk magnet platforms cooled with LN2 and Stirling cryo-cooler for demonstrator use. Compact cryostats for Maglev train operation contain 24 pieces of 3-seed bulks and can levitate 2500-3000 N at 10 mm above a permanent magnet (PM) track. The effective magnetic distance of the thermally insulated bulks is 2 mm only; the stored 2.5 l LN2 allows more than 24 h operation without refilling. 34 HTS Maglev vacuum cryostats are manufactured tested and operate in Germany, China and Brazil. The magnetic levitation load to weight ratio is more than 15, and by group assembling the HTS cryostats under vehicles up to 5 t total loads levitated above a magnetic track is achieved.

  17. Development of HTS Cable System for ALBANY Project

    NASA Astrophysics Data System (ADS)

    Watanabe, M.; Yumura, H.; Takigawa, H.; Ito, H.; Ashibe, Y.; Kato, T.; Suzawa, C.; Masuda, T.; Sato, K.; Isojima, S.

    2006-06-01

    High temperature superconducting (HTS) cable is anticipated to transmit a large amount of electricity with a compact size and can reduce the transmission loss and greenhouse gas emission. The Albany project is being undertaken to verify the practicability of a long HTS cable in the real grid by performing a long-term operation test. The cable is 350-meter long and carries 800 A at 34.5 kV between two electric power substations (Menands and Riverside) in Albany, N.Y. [1]. The project is scheduled to run from 2002 to 2007 and is proceeding as planned. The HTS cable and its apparatus were manufactured in Japan, and the cable was shipped to the USA in the middle of August. After it arrives at the site, the cable installation and the apparatus assembly will be carried out sequentially. This system is expected to begin operating early next year after initial cooling. This paper gives an overview and the current status of the development of the HTS cable system.

  18. HTS DC Transmission Line for Megalopolis Grid Development

    NASA Astrophysics Data System (ADS)

    Kopylov, S.; Sytnikov, V.; Bemert, S.; Ivanov, Yu; Krivetskiy, I.; Romashov, M.; Shakaryan, Yu; Keilin, V.; Shikov, A.; Patrikeev, V.; Lobyntsev, V.; Shcherbakov, V.

    2014-05-01

    Using of HTS AC and DC cables in electric power grids allows increasing of the transferred power, losses diminishing, decreasing of exclusion zone areas, the enhancement of the environmental conditions and fire/explosion safety of electric power systems. However, the use of DC superconducting cable lines together with converters brings additional advantages as reduction of losses in cables and suitable lowering of refrigerating plant capacity, as well as the realization of the function of short-circuit currents limitation by means of the appropriate setting of converter equipment. Russian Federal Grid Company and its R&D Center started the construction of the DC HTS power transmission line which includes the cable itself, cryogenic equipment, AC/DC converters, terminals and cable coupling boxes. This line will connect two substations in Saint-Petersburg - 330 kV "Centralnaya" and 220 kV "RP-9". The length of this HTS transmission line will be about 2500 meters. Nowadays are developed all the elements of the line and technologies of the cable manufacturing. Two HTS cable samples, each 30 m length, have been made. This paper describes the results of cables tests.

  19. Thermal management of long-length HTS cable systems

    SciTech Connect

    Demko, Jonathan A; Hassenzahl, William V

    2011-01-01

    Projections of electric power production suggest a major shift to renewables, such as wind and solar, which will be in remote locations where massive quantities of power are available. One solution for transmitting this power over long distances to load centers is direct current (dc), high temperature superconducting (HTS) cables. Electric transmission via dc cables promises to be effective because of the low-loss, highcurrent- carrying capability of HTS wire at cryogenic temperatures. However, the thermal management system for the cable must be carefully designed to achieve reliable and energyefficient operation. Here we extend the analysis of a superconducting dc cable concept proposed by the Electric Power Research Institute (EPRI), which has one stream of liquid nitrogen flowing in a cryogenic enclosure that includes the power cable, and a separate return tube for the nitrogen. Refrigeration stations positioned every 10 to 20 km cool both nitrogen streams. Both go and return lines are contained in a single vacuum/cryogenic envelope. Other coolants, including gaseous helium and gaseous hydrogen, could provide potential advantages, though they bring some technical challenges to the operation of long-length HTS dc cable systems. A discussion of the heat produced in superconducting cables and a system to remove the heat are discussed. Also, an analysis of the use of various cryogenic fluids in long-distance HTS power cables is presented.

  20. Characteristics on electodynamic suspension simulator with HTS levitation magnet

    NASA Astrophysics Data System (ADS)

    Lee, J.; Bae, D. K.; Sim, K.; Chung, Y. D.; Lee, Y.-S.

    2009-10-01

    High- Tc superconducting (HTSC) electrodynamic suspension (EDS) system basically consists of the HTSC levitation magnet and the ground conductor. The levitation force of EDS system is forms by the interaction between the moving magnetic field produced by the onboard levitation magnet and the induced magnetic field produced by eddy current in the ground conductor. This paper deals with the characteristics of the EDS simulators with high- Tc superconducting (HTS) levitation magnet. Two EDS simulator systems, rotating type EDS simulator and static type EDS simulator, were studied in this paper. The rotating type EDS simulator consists of a HTS levitation magnet and a 1.5 m diameter rotating ground conductor, a motor, the supporting structure and force measuring devices. In the static type EDS simulator, instead of moving magnetic field, AC current was applied to the fixed HTS levitation magnet to induce the eddy current. The static type EDS simulator consists of a HTS levitation magnet, a ground conductor, force measuring devices and supporting structure. The double-pancake type HTSC levitation magnet was designed, manufactured and tested in the EDS simulator.

  1. A numerical model for stability considerations in HTS magnets

    NASA Astrophysics Data System (ADS)

    Lehtonen, Jorma; Mikkonen, Risto; Paasi, Jaakko

    2000-03-01

    We propose that in an HTS application, stability is lost more likely because of a global increase in temperature caused by heat generation distributed over the whole coil than because of a local normal zone which starts to propagate. For consideration of stability in HTS magnets, we present a computational model based on the heat conduction equation coupled with Maxwell's equations, whereby analysis can be performed by using commercial software packages for computational electromagnetics and thermodynamics. For temperature distribution inside the magnet, we derive the magnetic field dependent effective values of thermal conductivity, specific heat, and heat generated by electromagnetic phenomena for the composite structure of the magnet, while cooling conditions and external heat sources are described as boundary conditions. Our model enables the magnet designer to estimate a safe level of the operation current before a thermal runaway. Finally, as examples, we present some calculations of the HTS magnet with ac to review the effects of slanted electric field-current density E (J ) characteristics and high critical temperature of HTS materials.

  2. Test Results For a 25-m Prototype Fault Current Limiting HTS Cable for Project Hydra

    SciTech Connect

    Rey, Christopher M; Duckworth, Robert C; Demko, Jonathan A; Ellis, Alvin R; Gouge, Michael J; James, David Randy; Tuncer, Enis

    2010-01-01

    The Oak Ridge National Laboratory (ORNL) has tested a 25-m long prototype High Temperature Superconducting (HTS) cable with inherent Fault-Current Limiting (FCL) capability at its recently upgraded HTS cable test facility in Oak Ridge, TN. The HTS-FCL cable and terminations were designed and fabricated by Ultera, which is a joint venture of Southwire and nkt cables with FCL features and HTS wire provided by American Superconductor Corporation. The overall project is sponsored by the U.S. Department of Homeland Security. The ultimate goal of the 25-m HTS-FCL cable test program was to verify the design and ensure the operational integrity for the eventual installation of a ~ 200-m fully functional HTS-FCL cable in the Consolidated Edison electric grid located in downtown New York City. The 25-m HTS-FCL cable consisted of a three-phase (3- ) Triax design with a cold dielectric between the phases. The HTS-FCL cable had an operational voltage of 13.8 kV phase-to-phase and an operating current of 4000 Arms per phase, which is the highest operating current to date of any HTS cable. The 25-m HTS-FCL cable was subjected to a series of cryogenic and electrical tests. Test results from the 25-m HTS-FCL cable are presented and discussed.

  3. Enhancements to a superconducting quantum interference device (SQUID) multiplexer readout and control system

    NASA Astrophysics Data System (ADS)

    Forgione, Joshua B.; Benford, Dominic J.; Buchanan, Ernest D.; Moseley, S. H., Jr.; Rebar, Joyce; Shafer, Richard A.

    2004-10-01

    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 III 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 III 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.

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

    NASA Technical Reports Server (NTRS)

    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.

  5. SQUID magnetometry from nanometer to centimeter length scales

    SciTech Connect

    Hatridge, Michael J.

    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.

  6. Peripheral injury alters schooling behavior in squid, Doryteuthis pealeii.

    PubMed

    Oshima, Megumi; di Pauli von Treuheim, Theodor; Carroll, Julia; Hanlon, Roger T; Walters, Edgar T; Crook, Robyn J

    2016-07-01

    Animals with detectable injuries are at escalated threat of predation. The anti-predation tactic of schooling reduces individual predation risk overall, but it is not known how schooling behavior affects injured animals, or whether risks are reduced equally for injured animals versus other school members. In this laboratory study we examined the effects of minor fin injury on schooling decisions made by squid. Schooling behavior of groups of squid, in which one member was injured, was monitored over 24h. Injured squid were more likely to be members of a school shortly after injury (0.5-2h), but there were no differences compared with sham-injured squid at longer time points (6-24h). Overall, the presence of an injured conspecific increased the probability that a school would form, irrespective of whether the injured squid was a member of the school. When groups containing one injured squid were exposed to a predator cue, injured squid were more likely to join the school, but their position depended on whether the threat was a proximate visual cue or olfactory cue. We found no evidence that injured squid oriented themselves to conceal their injury from salient threats. Overall we conclude that nociceptive sensitization after injury changes grouping behaviors in ways that are likely to be adaptive. PMID:27108689

  7. Read-out electronics for DC squid magnetic measurements

    DOEpatents

    Ganther, Jr., Kenneth R.; Snapp, Lowell D.

    2002-01-01

    Read-out electronics for DC SQUID sensor systems, the read-out electronics incorporating low Johnson noise radio-frequency flux-locked loop circuitry and digital signal processing algorithms in order to improve upon the prior art by a factor of at least ten, thereby alleviating problems caused by magnetic interference when operating DC SQUID sensor systems in magnetically unshielded environments.

  8. Planar thin film SQUID with integral flux concentrator

    NASA Technical Reports Server (NTRS)

    Peters, Palmer N. (Inventor); Sisk, Robert C. (Inventor)

    1988-01-01

    A thin film SQUID is disclosed having improved flux concentration combined with simplicity of design and fabrication. The SQUID starts with a wafer like substrate having simple planar geometry. A large area of superconducting film is coated on the substrate, with a small open or uncoated area remaining at its center to define a SQUID loop, and a gap in the film formed, beginning at the outer circumferential edge of the substrate and extending radially inward to the open area. A Josephson junction is formed across the gap near the open area to interrupt the electrical continuity of the SQUID loop. A coil is attached to the surface of the substrate, electrically insulated from the superconducting film, and is energized to induce flux within the SQUID which is concentrated within the open area.

  9. A SQUID gradiometer module with large junction shunt resistors

    NASA Astrophysics Data System (ADS)

    Qiu, Yang; Liu, Chao; Zhang, Shu-Lin; Zhang, Guo-Feng; Wang, Yong-Liang; Li, Hua; Zeng, Jia; Kong, Xiang-Yan; Xie, Xiao-Ming

    2014-08-01

    A dual-washer superconducting quantum interference device (SQUID) with a loop inductance of 350 pH and two on-washer integrated input coils is designed according to conventional niobium technology. In order to obtain a large SQUID flux-to-voltage transfer coefficient, the junction shunt resistance is selected to be 33 Ω. A vertical SQUID gradiometer module with a baseline of 100 mm is constructed by utilizing such a SQUID and a first-order niobium wire-wound antenna. The sensitivity of this module reaches about 0.2 fT/(cm·Hz1/2) in the white noise range using a direct readout scheme, i.e., the SQUID is directly connected to an operational amplifier, in a magnetically shielded room. Some magnetocardiography (MCG) measurements with a sufficiently high signal-to-noise ratio (SNR) are demonstrated.

  10. Presynaptic calcium currents in squid giant synapse.

    PubMed Central

    Llinás, R; Steinberg, I Z; Walton, K

    1981-01-01

    A voltage clamp study has been performed in the presynaptic terminal of the squid stellate ganglion. After blockage of the voltage-dependent sodium and potassium conductances, an inward calcium current is demonstrated. Given a step-depolarization pulse, this voltage- and time-dependent conductance has an S-shaped onset. At the "break" of the voltage step, a rapid tail current is observed. From these results a kinetic model is generated which accounts for the experimental results and predicts for the time course and amplitude a possible calcium entry during presynaptic action potentials. Images FIGURE 1 PMID:7225510

  11. Moderately shielded high-Tc SQUID system for rat MCG

    NASA Astrophysics Data System (ADS)

    Bechstein, S.; Kim, I.-S.; Drung, D.; Novikov, I.; Schurig, Th

    2010-06-01

    Recently, we have developed a 5-channel high-Tc SQUID system with one signal channel intended for rat magnetocardiography (MCG) in moderately shielded or "quiet" real environment. This system is an adapted version of a human MCG system which has been improved with respect to user-friendliness and stability. A dewar with a cold-warm distance of 7 mm and a refill cycle time of up to one week is utilized. The implemented high-Tc SQUIDs are single-layer devices with grain boundary junctions fabricated at KRISS with laser ablation on 10 mm × 10 mm STO substrates. In order to cancel environmental magnetic noise, three of the five SQUIDs are arranged to build an axial software first-order or second-order gradiometer with a base line of 35 mm. The other two SQUIDs are used for balancing. To overcome previous system instabilities, we have implemented an Earth field compensation for each SQUID. For this, the SQUIDs were mounted in capsules containing integrated field compensation coils. The three Earth field components are measured with an additional triaxial fluxgate, and compensated at the SQUID locations using the low-noise current source of the SQUID readout electronics. This way, the SQUIDs can be cooled and operated in a low residual field that improves system stability and reduces low-frequency SQUID noise. It is even possible to slowly move the dewar in the Earth field (dynamic field compensation). Different noise cancellation procedures were optimized and compared employing a periodic signal source.

  12. HTS Fabry-Perot resonators for the far infrared

    SciTech Connect

    Keller, P.; Prenninger, M.; Pechen, E.V.; Renk, K.F.

    1996-12-31

    The authors report on far infrared (FIR) Fabry-Perot resonators (FPR) with high temperature superconductor (HTS) thin films as mirrors. For the fabrication of FPR they use two parallel MgO plates covered with YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} thin films on adjacent sides. They have measured the far-infrared transmissivity at 10 K with a Fourier transform infrared spectrometer. Very sharp resonances can be observed for frequencies below 6 THz where the MgO is transparent. The finesse (width of the first order resonance) is comparable to the FPR with metallic meshes as reflectors that are applied in the FIR spectroscopy and astronomy. They have also shown that thin films of gold are not an adequate substitute to HTS thin films and not suitable for the fabrication of high-quality FPR due to the ohmic losses.

  13. Development of Prototype HTS Components for Magnetic Suspension Applications

    NASA Technical Reports Server (NTRS)

    Haldar, P.; Hoehn, J., Jr.; Selvamanickam, V.; Farrell, R. A.; Balachandran, U.; Iyer, A. N.; Peterson, E.; Salazar, K.

    1996-01-01

    We have concentrated on developing prototype lengths of bismuth and thallium based silver sheathed superconductors by the powder-in-tube approach to fabricate high temperature superconducting (HTS) components for magnetic suspension applications. Long lengths of mono and multi filament tapes are presently being fabricated with critical current densities useful for maglev and many other applications. We have recently demonstrated the prototype manufacture of lengths exceeding 1 km of Bi-2223 multi filament conductor. Long lengths of thallium based multi-filament conductor have also been fabricated with practical levels of critical current density and improved field dependence behavior. Test coils and magnets have been built from these lengths and characterized over a range of temperatures and background fields to determine their performance. Work is in progress to develop, fabricate and test HTS windings that will be suitable for magnetic suspension, levitation and other electric power related applications.

  14. High voltage insulation of bushing for HTS power equipment

    NASA Astrophysics Data System (ADS)

    Kim, Woo-Jin; Choi, Jae-Hyeong; Kim, Sang-Hyun

    2012-12-01

    For the operation of high temperature superconducting (HTS) power equipments, it is necessary to develop insulating materials and high voltage (HV) insulation technology at cryogenic temperature of bushing. Liquid nitrogen (LN2) is an attractive dielectric liquid. Also, the polymer insulating materials are expected to be used as solid materials such as glass fiber reinforced plastic (GFRP), polytetra-fluoroethylene (PTFE, Teflon), Silicon (Si) rubber, aromatic polyamide (Nomex), EPDM/Silicon alloy compound (EPDM/Si). In this paper, the surface flashover characteristics of various insulating materials in LN2 are studied. These results are studied at both AC and impulse voltage under a non-uniform field. The use of GFRP and Teflon as insulation body for HTS bushing should be much desirable. Especially, GFRP is excellent material not only surface flashover characteristics but also mechanical characteristics at cryogenic temperature. The surface flashover is most serious problem for the shed design in LN2 and operation of superconducting equipments.

  15. A Compact, Modular Superconducting Bolometer Array Package

    NASA Technical Reports Server (NTRS)

    Benford, Dominic J.

    2008-01-01

    We have designed a detector package to house a superconducting bolometer array, SQUID multiplexers, bias and integration circuitry, optical filtering, electrical connectors, and thermal/mechanical interfaces. This package has been used successfully in the GISMO 2mm camera, a 128-pixel camera operating at a base temperature of 270mK. Operation at lower temperatures is allowed by providing direct heat sinking to the SQUIDS and bias resistors, which generate the bulk of the dissipation in the package. Standard electrical connectors provide reliable contact while enabling quick installation and removal of the package. Careful design has gone into the compensation for differing thermal expansions, the need for heat sinking of the bolometer array, and the placement of magnetic shielding in critical areas. In this presentation, we detail the design and performance of this detector package and describe its scalability to 1280- pixel arrays in the near future.

  16. A simple three-channel dc SQUID system using time domain multiplexing

    NASA Astrophysics Data System (ADS)

    Mück, M.; Korn, M.; Mugford, C. G. A.; Kycia, J. B.

    2004-08-01

    Conventional multichannel superconducting quantum interference device (SQUID) systems require a SQUID read-out circuit for each channel, as well as many wires connecting each individual SQUID and feedback coil to the room temperature electronics. We present a simple time domain multiplexed read-out scheme which requires only a single SQUID read-out circuit that is successively switched between all the SQUIDs. By connecting all the SQUIDs and all the feedback coils in series, this time domain multiplexed system requires many fewer wires between the SQUIDs and the room temperature read-out circuit than other multichannel systems.

  17. Test results of HTS magnet for SMES application

    NASA Astrophysics Data System (ADS)

    Kozak, J.; Majka, M.; Jaroszynski, L.; Janowski, T.; Kozak, S.; Kondratowicz – Kucewicz, B.; Wojtasiewicz, G.

    2010-06-01

    The magnet for a superconducting magnetic energy storage system (SMES) conducting cooled by SRDK-408 cryocooler is described in this paper. The superconducting magnet consists of 7 double-pancake coils made of Bi-2223 HTS tape with the inner and outer diameters 210 mm, 315 mm respectively and height of 191 mm. The inductance of the magnet is approximately 1 H. In this paper we report the design improvements and the measurement results taken at the cooling of the magnet.

  18. Cross-linking Chemistry of Squid Beak*

    PubMed Central

    Miserez, Ali; Rubin, Daniel; Waite, J. Herbert

    2010-01-01

    In stark contrast to most aggressive predators, Dosidicus gigas (jumbo squids) do not use minerals in their powerful mouthparts known as beaks. Their beaks instead consist of a highly sclerotized chitinous composite with incremental hydration from the tip to the base. We previously reported l-3,4-dihydroxyphenylalanine (dopa)-histidine (dopa-His) as an important covalent cross-link providing mechanical strengthening to the beak material. Here, we present a more complete characterization of the sclerotization chemistry and describe additional cross-links from D. gigas beak. All cross-links presented in this report share common building blocks, a family of di-, tri-, and tetra-histidine-catecholic adducts, that were separated by affinity chromatography and high performance liquid chromatography (HPLC) and identified by tandem mass spectroscopy and proton nuclear magnetic resonance (1H NMR). The data provide additional insights into the unusually high cross-link density found in mature beaks. Furthermore, we propose both a low molecular weight catechol, and peptidyl-dopa, to be sclerotization agents of squid beak. This appears to represent a new strategy for forming hard tissue in animals. The interplay between covalent cross-linking and dehydration on the graded properties of the beaks is discussed. PMID:20870720

  19. Cross-linking chemistry of squid beak.

    PubMed

    Miserez, Ali; Rubin, Daniel; Waite, J Herbert

    2010-12-01

    In stark contrast to most aggressive predators, Dosidicus gigas (jumbo squids) do not use minerals in their powerful mouthparts known as beaks. Their beaks instead consist of a highly sclerotized chitinous composite with incremental hydration from the tip to the base. We previously reported l-3,4-dihydroxyphenylalanine (dopa)-histidine (dopa-His) as an important covalent cross-link providing mechanical strengthening to the beak material. Here, we present a more complete characterization of the sclerotization chemistry and describe additional cross-links from D. gigas beak. All cross-links presented in this report share common building blocks, a family of di-, tri-, and tetra-histidine-catecholic adducts, that were separated by affinity chromatography and high performance liquid chromatography (HPLC) and identified by tandem mass spectroscopy and proton nuclear magnetic resonance ((1)H NMR). The data provide additional insights into the unusually high cross-link density found in mature beaks. Furthermore, we propose both a low molecular weight catechol, and peptidyl-dopa, to be sclerotization agents of squid beak. This appears to represent a new strategy for forming hard tissue in animals. The interplay between covalent cross-linking and dehydration on the graded properties of the beaks is discussed. PMID:20870720

  20. The curvy photonics of squid camouflage

    NASA Astrophysics Data System (ADS)

    Sweeney, Alison; Holt, Amanda; Daniel, Morse; Stramski, Dariusz

    2013-03-01

    Cephalopods (squids and octopuses) ubiquitously possess reflective structures in their skin composed of ``reflectin'' proteins. Although a few simple laminar, Bragg-stack type optical structures have been known in a handful of common squid species for some time, our extensive survey of optically active tissues of exotic deep-sea species has revealed complex, extended curvatures and topologies in dermal reflectors of these rarely-studied animals. Molecular deep-sequencing has revealed these structures also to be composed of reflectin-like proteins. Here we show a survey of some of these deep-sea reflector structures, and present evidence that each novel structure may be a transform of the radiance in the optical niche in the ocean where each of these species live, such that light reflecting off the sides of these animals in their specific ocean habitat resembles the light that would be transmitted through the animals if they were transparent, from many different viewing angles and possible ocean depths.

  1. Crystallization and crystal properties of squid rhodopsin

    SciTech Connect

    Murakami, Midori; Kitahara, Rei; Gotoh, Toshiaki; Kouyama, Tsutomu

    2007-06-01

    Truncated rhodopsin from the retina of the squid Todarodes pacificus was extracted and crystallized by the sitting-drop vapour-diffusion method. Hexagonal crystals grown in the presence of octylglucoside and ammonium sulfate diffracted to 2.8 Å resolution. Rhodopsin, a photoreceptor membrane protein in the retina, is a prototypical member of the G-protein-coupled receptor family. In this study, rhodopsin from the retina of the squid Todarodes pacificus was treated with V8 protease to remove the C-terminal extension. Truncated rhodopsin was selectively extracted from the microvillar membranes using alkyl glucoside in the presence of zinc ions and was then crystallized by the sitting-drop vapour-diffusion method. Of the various crystals obtained, hexagonal crystals grown in the presence of octylglucoside and ammonium sulfate diffracted to 2.8 Å resolution. The diffraction data suggested that the crystal belongs to space group P6{sub 2}, with unit-cell parameters a = b = 122.1, c = 158.6 Å. Preliminary crystallographic analysis, together with linear dichroism results, suggested that the rhodopsin dimers are packed in such a manner that their transmembrane helices are aligned nearly parallel to the c axis.

  2. Base distance optimization for SQUID gradiometers

    SciTech Connect

    Garachtchenko, A.; Matlashov, A.; Kraus, R.

    1998-12-31

    The measurement of magnetic fields generated by weak nearby biomagnetic sources is affected by ambient noise generated by distant sources both internal and external to the subject under study. External ambient noise results from sources with numerous origins, many of which are unpredictable in nature. Internal noise sources are biomagnetic in nature and result from muscle activity (such as the heart, eye blinks, respiration, etc.), pulsation associated with blood flow, surgical implants, etc. Any magnetic noise will interfere with measurements of magnetic sources of interest, such as magnetoencephalography (MEG), in various ways. One of the most effective methods of reducing the magnetic noise measured by the SQUID sensor is to use properly designed superconducting gradiometers. Here, the authors optimized the baseline length of SQUID-based symmetric axial gradiometers using computer simulation. The signal-to-noise ratio (SNR) was used as the optimization criteria. They found that in most cases the optimal baseline is not equal to the depth of the primary source, rather it has a more complex dependence on the gradiometer balance and the ambient magnetic noise. They studied both first and second order gradiometers in simulated shielded environments and only second order gradiometers in a simulated unshielded environment. The noise source was simulated as a distant dipolar source for the shielded cases. They present optimal gradiometer baseline lengths for the various simulated situations below.

  3. Large Scale Applications of HTS in New Zealand

    NASA Astrophysics Data System (ADS)

    Wimbush, Stuart C.

    New Zealand has one of the longest-running and most consistently funded (relative to GDP) programmes in high temperature superconductor (HTS) development and application worldwide. As a consequence, it has a sustained breadth of involvement in HTS technology development stretching from the materials discovery right through to burgeoning commercial exploitation. This review paper outlines the present large scale projects of the research team at the newly-established Robinson Research Institute of Victoria University of Wellington. These include the construction and grid-based testing of a three-phase 1 MVA 2G HTS distribution transformer utilizing Roebel cable for its high-current secondary windings and the development of a cryogen-free conduction-cooled 1.5 T YBCO-based human extremity magnetic resonance imaging system. Ongoing activities supporting applications development such as low-temperature full-current characterization of commercial superconducting wires and the implementation of inductive flux-pump technologies for efficient brushless coil excitation in superconducting magnets and rotating machines are also described.

  4. Development of Substrate for RABiTS-based HTS Conductors

    SciTech Connect

    2009-06-05

    During its fifteen years of life, this CRADA has evolved in both scope and purpose. Early efforts to develop high performance bismuth-based powder-in-tube first generation high temperature superconductors (HTS) have shifted toward efforts to understand and develop technologies required to fabricate second generation HTS coated conductors. Since the two original longstanding principal investigators from UT-Battelle and Oxford Superconducting Technology (OST) are not presently employed by their respective organizations, this final report shall focus primarily on results of the more recent past involving research and development of the deformation and annealing processes required to fabricate metallic substrates for RABiTS-based second generation coated conductors. The specific objectives of this recent work involve the development of OST Ni/3%W tape for HTS coated conductors and include: (a) to improve uniformity of cube texture through control of deformation and annealing parameters, (b) to minimize delamination and other buffer deposition problems through understanding and control of key parameters related to the metal substrate, (c) to ensure that the textured metal substrate allows well textured buffers with no delamination, and (d) to prepared a final report.

  5. Testing of an HTS Power Cable Made from YBCO Tapes

    SciTech Connect

    Gouge, Michael J; Duckworth, Robert C; Demko, Jonathan A; Rey, Christopher M; Lindsay, David T; Roden, Mark L; Tolbert, Jerry Carlton

    2007-01-01

    Oak Ridge National Laboratory (ORNL) has designed, built, and tested a 1.25-m-long, prototype high temperature superconducting (HTS) power cable made from second-generation YBa2Cu3Ox (YBCO)-coated conductor tapes. Electrical tests of this cable were performed in liquid nitrogen at 77 K. DC testing of the HTS cable included determination of the V-I curve with a critical current of about 2100 A, which was consistent with the critical currents of the two layers of 4.4-mm wide YBCO tapes. AC testing of the cable was conducted at currents up to about 1500 Arms. The ac losses were determined calorimetrically by measuring the response of a calibrated temperature sensor placed on the former and electrically by use of a Rogowski coil with a lock-in amplifier. Over-current testing was conducted at peak current values up to 4.9 kA for pulse lengths of 0.3-0.5 s. Test results are compared to earlier data from a 1.25-m-long power cable made from 1-cm-wide YBCO tapes and also comparable BSCCO cables. This commercial-grade HTS cable demonstrated the feasibility of second-generation YBCO tapes in an ac cable application.

  6. Bi-2223/Ag HTS coil magnetic field properties for magnet and bias winding

    NASA Astrophysics Data System (ADS)

    Jin, J. X.; Grantham, C.; Liu, H. K.; Dou, S. X.

    1997-08-01

    Ag-clad (Bi,Pb)2Sr2Ca2Cu3O10+x high-Tc supercondicting (HTS) multifilament wire, is used to prepare a HTS coil. The magnetic field behaviour of the HTS coil is studied with respect to its critical current and magnetic field properties. The anisotropic HTS wire has strong magnetic field dependent critical current, which causes critical current degradation when used in the form of a coil. The HTS coil magnetic field is measured and its distribution is investigated. The experimental results and analysis provide basic information for the design of a magnet or bias winding with the Ag-clad (Bi,Pb)2Sr2Ca2Cu3O10+x HTS wire.

  7. The insulation design for transmission class HTS transformer with continuous disk winding

    NASA Astrophysics Data System (ADS)

    Cheon, H. G.; Kwag, D. S.; Choi, J. H.; Kim, S. H.

    2007-10-01

    In the response to the demands for electrical energy, much effort aimed to develop and commercialize HTS power equipments have been made around the world. Among them HTS transformer is one of very promising one. In Korea, companies and universities are developing a power distribution and transmission class HTS transformer that is one of the 21st century superconducting frontier projects. The composite continuous disk winding of transmission class HTS transformer is concentrically arranged H1-L-H2 from center. For the development of transmission HTS transformer with continuous disk winding, the cryogenic insulation technology should be established. We have been analyzed insulation composition and investigated electrical characteristics such as the breakdown of LN2, barrier, kapton films, flashover on FRP in LN2. We are going to compare with measured each value and apply the value to most suitable insulating design of the HTS transformer.

  8. Whole-head SQUID system in a superconducting magnetic shield.

    PubMed

    Ohta, H; Matsui, T; Uchikawa, Y

    2004-01-01

    We have constructed a mobile whole-head SQUID system in a superconducting magnetic shield - a cylinder of high Tc superconductor BSCCO of 65 cm in diameter and 160 cm in length. We compared the noise spectra of several SQUID sensors of SNS Josephson junctions in the superconducting magnetic shield with those of the same SQUID sensors in a magnetically shielded room of Permalloy. The SQUID sensors in the superconducting magnetic shield are more than 100 times more sensitive than those in a magnetically shielded room of Permalloy below 1 Hz. We tested the whole-head SQUID system in the superconducting magnetic shield observing somatosensory signals evoked by stimulating the median nerve in the right wrist of patients by current pulses. We present data of 64 and 128 traces versus the common time axis for comparison. Most sensory responses of human brains phase out near 250 ms. However monotonic rhythms still remain even at longer latencies than 250 ms. The nodes of these rhythm are very narrow even at these longer latencies just indicating low noise characteristics of the SQUID system at low-frequencies. The current dipoles at the secondary somatosensory area SII are evoked at longer latencies than 250 ms contributing to a higher-level brain function. The SQUID system in a superconducting magnetic shield will also have advantages when it is used as a DC MEG to study very slow activities and function of the brain. PMID:16012595

  9. High speed non-latching SQUID binary ripple counter

    NASA Astrophysics Data System (ADS)

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

    1985-03-01

    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/Nb2O5/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.

  10. High speed non-latching squid binary ripple counter

    SciTech Connect

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

    1985-03-01

    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/sub 2/O/sub 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.

  11. Recent Results of a New Microwave SQUID Multiplexer

    NASA Technical Reports Server (NTRS)

    Hahn, Inseob; Limketkai, B.; Bumble, B.; LeDuc, H. G.

    2007-01-01

    We are developing a proof-of-concept microwave SQUID multiplexer containing four SQUIDs coupled to GHz frequency resonant circuits and fed with a single microwave readout line. The resonators are half-wave coplanar waveguide sections and are similar to the structures used for the microwave kinetic inductance detectors developed in our group. Optimal values for the interdigital gap capacitors were determined to maximize the sensitivity of the transmitted and reflected microwave signal with respect to changes in the dynamic resistance of the SQUID. The dc current-bias line for the SQUID has an in-line inductive high frequency filter to minimize coupling between the bias line and resonator. A high frequency modulation scheme is proposed to eliminate the need for individual flux biasing of the SQUIDs, which extends the dynamic range of the readout. In this scheme a common modulation signal is imposed on each SQUID and the received signal is demodulated at one and two times the modulation frequency to maintain sensitivity at any flux state. We present the recent results of the microwave SQUID multiplexer system operating at a readout frequency range of 10 - 11GHz.

  12. Ginzburg-Landau modeling of Nano-SQUIDs

    NASA Astrophysics Data System (ADS)

    Kirtley, John; Hazra, Dibyendu; Hasselbach, Klaus; Buisson, Olivier

    2014-03-01

    NanoSQUIDs are micron-sized Superconducting Quantum Interference Devices with narrow (50 nm) sized constrictions as weak links. They are used for, e.g., studying switching dynamics in magnetic nanoparticles and high spatial resolution magnetic microscopy. When the constriction dimensions become comparable to or larger than the superconducting coherence length, the current-phase relations become non-sinusoidal, reducing the flux modulation depth and increasing the thermally activated flux noise. We have numerically solved the Ginzburg-Landau (GL) equations for the nanoSQUID geometry to obtain current-phase relations, the dependence of critical current on magnetic flux, and the thermally activated escape rates. We predict NanoSQUIDs with short coherence lengths to have critical current distribution widths, and therefore flux noises, proportional to T1/2, as opposed to tunnel junction SQUIDs, which are proportional to T2/3. Our GL simulations predict that the ultimate noise performance of Al nanoSQUIDs, with their longer coherence lengths, should be better than Nb nanoSQUIDs, with suspended bridge Al/Nb nanoSQUIDs intermediate between the two.

  13. Multichannel SQUID system for measurement of spinal cord evoked magnetic field for supine subjects

    NASA Astrophysics Data System (ADS)

    Adachi, Y.; Kawai, J.; Miyamoto, M.; Uehara, G.; Ogata, H.; Kawabata, S.

    2008-02-01

    A SQUID biomagnetometer system for cervical spinal cord evoked field (SCEF) was developed to investigate a non-invasive diagnosis of function of the spinal cord. The measurement system was characterized by a uniquely shaped cryostat designed for supine subjects. The cryostat has a vertical cylindrical main body whose dimensions are 500 mm in diameter and 940 mm in height and a horizontal protrusion from the side surface with 390 mm of length. The sensor array of 35 LTS-SQUID vector gradiometers directed vertically upward is installed in the end of the protruded part. Subjects lie on a bed in supine position with the head running off the edge of the bed and the back of the neck supported on the upper surface of the protruded part of the cryostat standing beside the bed. This structure readily enables the sensor array to approach close to the neck of the supine subject. The subjects can keep their posture stable during the measurement. We demonstrated the cervical SCEF was successfully detected from a healthy subject who was given electric stimulation to the median nerve at the wrist. The intensity of the evoked magnetic field was 40-70 fT in amplitude. The neural signal propagating along the spinal cord was magnetically observed from the investigation of the transition of the magnetic field distribution.

  14. Synchronous Generator with HTS-2G field coils for Windmills with output power 1 MW

    NASA Astrophysics Data System (ADS)

    Kovalev, K.; Kovalev, L.; Poltavets, V.; Samsonovich, S.; Ilyasov, R.; Levin, A.; Surin, M.

    2014-05-01

    Nowadays synchronous generators for wind-mills are developed worldwide. The cost of the generator is determined by its size and weight. In this deal the implementation of HTS-2G generators is very perspective. The application of HTS 2G field coils in the rotor allows to reduce the size of the generator is 1.75 times. In this work the design 1 MW HTS-2G generator is considered. The designed 1 MW HTS-2G generator has the following parameters: rotor diameter 800 mm, active length 400 mm, phase voltage 690V, rotor speed 600 min-1 rotor field coils with HTS-2G tapes. HTS-2G field coils located in the rotating cryostat and cooled by liquid nitrogen. The simulation and optimization of HTS-2G field coils geometry allowed to increase feed DC current up to 50A. Copper stator windings are water cooled. Magnetic and electrical losses in 1 MW HTS-2G generator do not exceed 1.6% of the nominal output power. In the construction of HTS-2G generator the wave multiplier with ratio 1:40 is used. The latter allows to reduce the total mass of HTS-2G generator down to 1.5 tons. The small-scale model of HTS-2G generator with output power 50 kW was designed, manufactured and tested. The test results showed good agreement with calculation results. The manufacturing of 1 MW HTS-2G generator is planned in 2014. This work is done under support of Rosatom within the frames of Russian Project "Superconducting Industry".

  15. Dynamics of a SQUID with topologically nontrivial barriers

    NASA Astrophysics Data System (ADS)

    Rahmonov, I. R.; Shukrinov, Yu. M.; Dawood, R.

    2016-03-01

    The phase dynamics of a SQUID consisting of Josephson junctions with topologically nontrivial barriers has been studied. Its comparative analysis with the dynamics of a conventional SQUID has been performed. The current-voltage characteristics have been calculated. The dependence of the return current on the magnetic field has been found. It has been shown that the branch of the current-voltage characteristic corresponding to the resonance frequency in the case of the SQUID with nontrivial barriers is displaced by √ 2 over voltage. This effect can be used for the detection of Majorana fermions.

  16. Resonance detection of dark matter axions using a DC SQUID

    NASA Astrophysics Data System (ADS)

    Popov, V. A.

    2016-02-01

    A method for detecting dark matter axions in which a dc SQUID serves as a detector is proposed. The SQUID is shown to be able to detect the magnetic field perturbations induced by its interaction with axions. The resonance signal appears as a current step in the SQUID current-voltage characteristic. The voltage of the step corresponds to the axion mass, while its height depends on the axion energy density in near-Earth space. The proposed method is aimed at detecting axions with masses m a ≲ 10-4 eV, which are of interest for both cosmology and particle physics.

  17. TEST RESULTS OF HTS COILS AND AN R AND D MAGNET FOR RIA.

    SciTech Connect

    GUPTA, R.; ANERELLA, M.; HARRISON, M.; SCHMALZLE, J.; SAMPSON, W.; ZELLER, A.

    2005-05-16

    This paper presents the successful construction and test results of a magnetic mirror model for the Rare Isotope Accelerator (RIA) that is based on High Temperature Superconductors (HTS). In addition, the performance of thirteen coils (each made with {approx}220 meters of commercially available HTS tape) is also presented. The proposed HTS magnet is a crucial part of the R&D for the Fragment Separator region where the magnets are subjected to several orders of magnitude more radiation and energy deposition than typical beam line and accelerator magnets receive during their entire lifetime. A preliminary design of an HTS dipole magnet for the Fragment Separator region is also presented.

  18. Hysteresis and reluctance electric machines with bulk HTS elements. Recent results and future development

    NASA Astrophysics Data System (ADS)

    Kovalev, L. K.; Ilushin, K. V.; Penkin, V. T.; Kovalev, K. L.; M-A Koneev, S.; Poltavets, V. N.; Larionoff, A. E.; Modestov, K. A.; Larionoff, S. A.; Gawalek, W.; Habisreuther, T.; Oswald, B.; Best, K.-J.; Strasser, T.

    2000-05-01

    Two new types of HTS electric machine are considered. The first type is hysteresis motors and generators with cylindrical and disc rotors containing bulk HTS elements. The second type is reluctance motors with compound HTS-ferromagnetic rotors. The compound HTS-ferromagnetic rotors, consisting of joined alternating bulk HTS (YBCO) and ferromagnetic (iron) plates, provide a new active material for electromechanical purposes. Such rotors have anisotropic properties (ferromagnetic in one direction and diamagnetic in the perpendicular one). Theoretical and experimental results for HTS hysteresis and reluctance motors are presented. A series of hysteresis HTS motors with output power rating from 1 kW (at 50 Hz) up to 4 kW (at 400 Hz) and a series of reluctance HTS motors with output power 2-18.5 kW (at 50 Hz) were constructed and successfully tested. It was shown that HTS reluctance motors could reach two to five times better overall dimensions and specific power than conventional asynchronous motors of the same size and will have higher values of power factor (cos ϕ≥0.7 to 0.8).

  19. Martian paleomagnetism with the SQUID microscope

    NASA Astrophysics Data System (ADS)

    Weiss, Benjamin Paul

    Rocks should preserve natural remanent magnetizations with stable directional and intensity information at levels ˜1000 times below that of the noise level on today's best moment magnetometers. The superconducting quantum interference device (SQUID) Microscope is a new, high-resolution magnetometer that can now detect such weak signals. It maps the magnetic fields above samples with a spatial resolution of <100 mum and a moment sensitivity of <10 -15 Am2. It therefore provides data with a resolution directly comparable with that of other common petrographic techniques. This thesis describes applications of SQUID microscopy to a variety of problems in the planetary sciences. A SQUID microscope paleomagnetic conglomerate test demonstrates that ALH84001 has been cooler than ˜40°C since before its ejection from the surface of Mars at 15 Ma. Because this temperature cannot sterilize most bacteria or eukarya, these data support the hypothesis that meteorites could transfer life between planets in the solar system. These and other data on panspermia demand a re-evaluation of the long-held assumption that terrestrial life evolved in isolation on Earth. Subsequent magnetic and textural studies of the meteorite show that 4 Ga ALH84001 carbonates containing magnetite and pyrrhotite carry a stable natural remanent magnetization. 40Ar/39Ar thermochronology demonstrates that this magnetization originated at 3.9--4.1 Ga on Mars. This magnetization is the oldest known for a planetary rock, and its strong intensity suggests that Mars had generated a geodynamo at or before 4 Ga. The intensity of the field that magnetized ALH84001 was roughly within an order of magnitude of that at the surface of the present-day Earth, sufficient for magnetotaxis by the bacteria whose magnetofossils have been reported in ALH84001 and possibly for the production of the strong crustal anomalies. 40Ar/39Ar thermochronology calculations also provide an explanation for why ALH84001 contains a sample of

  20. BabySQUID: A mobile, high-resolution multichannel magnetoencephalography system for neonatal brain assessment

    NASA Astrophysics Data System (ADS)

    Okada, Yoshio; Pratt, Kevin; Atwood, Christopher; Mascarenas, Anthony; Reineman, Richard; Nurminen, Jussi; Paulson, Douglas

    2006-02-01

    We developed a prototype of a mobile, high-resolution, multichannel magnetoencephalography (MEG) system, called babySQUID, for assessing brain functions in newborns and infants. Unlike electroencephalography, MEG signals are not distorted by the scalp or the fontanels and sutures in the skull. Thus, brain activity can be measured and localized with MEG as if the sensors were above an exposed brain. The babySQUID is housed in a moveable cart small enough to be transported from one room to another. To assess brain functions, one places the baby on the bed of the cart and the head on its headrest with MEG sensors just below. The sensor array consists of 76 first-order axial gradiometers, each with a pickup coil diameter of 6mm and a baseline of 30mm, in a high-density array with a spacing of 12-14mm center-to-center. The pickup coils are 6±1mm below the outer surface of the headrest. The short gap provides unprecedented sensitivity since the scalp and skull are thin (as little as 3-4mm altogether) in babies. In an electromagnetically unshielded room in a hospital, the field sensitivity at 1kHz was ˜17fT/√Hz. The noise was reduced from ˜400to200fT/√Hz at 1Hz using a reference cancellation technique and further to ˜40fT/√Hz using a gradient common mode rejection technique. Although the residual environmental magnetic noise interfered with the operation of the babySQUID, the instrument functioned sufficiently well to detect spontaneous brain signals from babies with a signal to noise ratio (SNR) of as much as 7.6:1. In a magnetically shielded room, the field sensitivity was 17fT/√Hz at 20Hz and 30fT/√Hz at 1Hz without implementation of reference or gradient cancellation. The sensitivity was sufficiently high to detect spontaneous brain activity from a 7month old baby with a SNR as much as 40:1 and evoked somatosensory responses with a 50Hz bandwidth after as little as four averages. We expect that both the noise and the sensor gap can be reduced further by

  1. Calibration of Hall sensor array for critical current measurement of YBCO tape with ferromagnetic substrate

    NASA Astrophysics Data System (ADS)

    Zhu, Yunpeng; Wang, Gang; Liu, Liyuan; Yang, Xinsheng; Zhao, Yong

    2015-12-01

    HAS (Hall sensor array) is a powerful tool to detect the uniformity of HTS (high temperature superconductor) tape through mapping the distribution of remanent or shielding field along the surface of the tape. However, measurement of HTS tape with ferromagnetic parts by HSA is still an issue because the ferromagnetic substrate has influence on the magnetic field around the HTS layer. In this work, a continuous HSA system has been designed to measure the critical current of the YBCO tape with ferromagnetic substrate. The relationship between the remanent field and critical current was calibrated by the finite element method. The result showed that the HSA is an effective method for evaluating the critical current of the HTS tape with ferromagnetic substrate.

  2. Realizing and optimizing an atomtronic SQUID

    NASA Astrophysics Data System (ADS)

    Mathey, Amy C.; Mathey, L.

    2016-05-01

    We demonstrate how a toroidal Bose–Einstein condensate with a movable barrier can be used to realize an atomtronic SQUID. The magnitude of the barrier height, which creates the analogue of an SNS junction, is of crucial importance, as well as its ramp-up and -down protocol. For too low of a barrier, the relaxation of the system is dynamically suppressed, due to the small rate of phase slips at the barrier. For a higher barrier, the phase coherence across the barrier is suppressed due to thermal fluctuations, which are included in our Truncated Wigner approach. Furthermore, we show that the ramp-up protocol of the barrier can be improved by ramping up its height first, and its velocity after that. This protocol can be further improved by optimizing the ramp-up and ramp-down time scales, which is of direct practical relevance for on-going experimental realizations.

  3. Squid as nutrient vectors linking Southwest Atlantic marine ecosystems

    NASA Astrophysics Data System (ADS)

    Arkhipkin, Alexander I.

    2013-10-01

    Long-term investigations of three abundant nektonic squid species from the Southwest Atlantic, Illex argentinus, Doryteuthis gahi and Onykia ingens, permitted to estimate important population parameters including individual growth rates, duration of ontogenetic phases and mortalities. Using production model, the productivity of squid populations at different phases of their life cycle was assessed and the amount of biomass they convey between marine ecosystems as a result of their ontogenetic migrations was quantified. It was found that squid are major nutrient vectors and play a key role as transient 'biological pumps' linking spatially distinct marine ecosystems. I. argentinus has the largest impact in all three ecosystems it encounters due to its high abundance and productivity. The variable nature of squid populations increases the vulnerability of these biological conveyers to overfishing and environmental change. Failure of these critical biological pathways may induce irreversible long-term consequences for biodiversity, resource abundance and spatial availability in the world ocean.

  4. Integrated SQUID sensors for low cross-talk multichannel systems

    NASA Astrophysics Data System (ADS)

    Granata, C.; Vettoliere, A.; Luiso, M.; Russo, M.

    2006-06-01

    We present a fully integrated dc-SQUID magnetometer based on niobium technology including a new feedback coil design. In respect to a standard SQUID design, such a feedback-coil design was optimized in order to reduce the mutual inductance with the neighbours and to increase the coupling with the pick-up coil of the SQUID itself. In such a way, it is possible to reduce cross-talks due to both feedback coil and wires. Experimental results about the characterization of the device and the crosstalk measurements are reported. The measurements have been performed in liquid helium using a low noise readout electronics specifically designed for large multichannel SQUID based instrumentations. The experimental data have shown a substantial reduction of cross-talk between neighbouring sensors.

  5. Magnetic Field Sampling using a Pulsed Hysteretic SQUID

    NASA Astrophysics Data System (ADS)

    Kwon, S. P.; Vlahacos, C. P.; Berkley, A. J.; Gubrud, M. A.; Wellstood, F. C.; Cawthorne, A.

    2004-03-01

    Weak magnetic field detection using a non-hysteretic DC SQUID with Flux-Locked-Loop electronics is typically limited to 1MHz bandwidth or less. However, there is demand for larger bandwidth magnetic field detection for use in the semiconductor industry. We have studied the possibility of using a 4.2K hysteretic trilayer Nb DC SQUID, fabricated by Hypres Inc., with pulsed bias current to increase the bandwidth by an order of magnitude or more. The technique is based on the fast switching of a hysteretic SQUID from the superconducting state to the normal conducting state. By observing the switching of the SQUID, the applied magnetic field at the time of a pulse can be followed. Experimental results show that the technique can be used to follow magnetic fields of up to 60MHz with 5ns pulses. With shorter pulses and better electronics, the technique could further increase the bandwidth by another order of magnitude.

  6. ELECTROPHORETIC AND IMMUNOLOGICAL STUDIES OF SQUID AXOPLASM PROTEINS.

    PubMed

    HUNEEUS-COX, F

    1964-03-01

    By disc electrophoresis of the axoplasm of Dosidicus gigas, 14 protein bands have been resolved. Anti-bodies to the intra-axonal proteins and to squid blood proteins were produced in rabbits. By Ouchterlony's technique, six antigenic components can be demonstrated in axoplasm; the combined use of disc electrophoresis and immune diflusion in agar resolves seven antigenic components in axoplasm; none of these components is detectable in squid blood. PMID:14107426

  7. SQUID magnetometry applied as non-invasive electroanalytic chemical technique

    SciTech Connect

    Jette, B.D.; MacVicar, M.L.A. )

    1991-03-01

    This paper reports on a SQUID magnetometer, employed as a highly sensitive ammeter, used to perform standard electroanalytic chemical measurements non- invasively. Specifically, the magnetic fields generated by the net ionic movement in the solution of a driven electrochemical system is detected by the gradiometer coils. The SQUID signal can then be compared to conventional current measurements. One such standard measurement investigated is Cyclic Voltametry (CV) which determines the I-V characteristics of an electrochemical system yielding critical kinetic parameters.

  8. High-T(c) squid application in medicine and geophysics

    NASA Technical Reports Server (NTRS)

    Polushkin, V. N.; Uchaikin, S. V.; Vasiliev, B. V.

    1991-01-01

    In our laboratory of high-T(sub c), a one-hole squid was built from Y1Ba2Cu3O(7-x) ceramics obtained by a standard procedure of solid state reaction. The ceramics with critical current density J(sub c) is greater than 100 A/sq cm was selected. In the middle of a 10 x 10 x 2 mm ceramics pellet, a 0.8 mm hole was drilled in which the superconducting loop of the squid was located. Between the hole and the edge of the pellet, a cut was mechanically filed out with a bridge inside it connecting the superconducting ring. A scheme of the magnetometer is presented. The resonant frequency shift of the tank circuit, the connection of the squid with this circuit, and the squid inductance are evaluated. One of the most interesting fields of the squid-based magnetometer application is biomagnetism, particularly, the human heart magnetocardiogram measuring. The low-temperature squids were used in this area and many interesting and important scientific results have been obtained. The observations have shown that the main noise contribution was not due to the squid but to the Earth's magnetic field variations, industrial inductions, and mainly to the vibrations caused by liquid nitrogen boiling and by vibrations of the box. Further attempts are needed to reduce the magnetic noise inductions. Nevertheless, the estimations promise the maximum signal/noise relation of the high-T(sub c) squid-magnetocardiometer to be not less than 10:1 in a bandwidth of 60 Hz. Apparently, such resolution would be enough not only for steady cardiogram reading but even for thin structure investigation at average technique application.

  9. High transition-temperature SQUID magnetometers and practical applications

    SciTech Connect

    Dantsker, E

    1997-05-01

    The design, fabrication and performance of SQUID magnetometers based on thin films of the high-transition temperature superconductor YBa{sub 2}Cu{sub 3}O{sub 7{minus}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{sub 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{sup {minus}1/2} at 1 Hz and 8.5 fT Hz{sup {minus}1/2} at 1 kHz. A multiloop multilayer SQUID magnetometer had a field noise of 37 fT Hz{sup {minus}1/2} at 1 Hz and 18 fT Hz{sup {minus}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.

  10. High-performance DC SQUID read-out electronics

    NASA Astrophysics Data System (ADS)

    Drung, Dietmar

    2002-03-01

    The dynamic behavior of superconducting quantum interference devices (SQUIDs) operated in a flux-locked loop (FLL) is discussed using a simple mathematical description. It is shown that the slew rate of any FLL is limited by the linear flux range of the SQUID Φlin and the effective loop delay td to approximately Φ˙f, max=Φ lin/(4t d) if a one-pole integrator is used. This allows one to estimate the dynamic limits of both analog SQUIDs with flux modulation or direct read-out and digital SQUIDs with on-chip read-out. In addition to theoretical limits, practically achievable performance is presented using our latest direct-coupled FLL electronics as an example of state-of-the-art SQUID read-out. This electronics is designed for both low-critical temperature (low- Tc) and high- Tc SQUIDs. It combines low noise with high bandwidth and slew rate. All functions are computer controlled using a LabVIEW ® program. An automatic bias voltage tuning circuit increases the system stability in case of large cryogenic temperature fluctuations. Furthermore, an ultra-low-noise current source is integrated into the FLL board which can be used to supply a coil system compensating the Earth's magnetic field of about 60 μT while producing only 17 fT/ Hz extra noise at 1 kHz and 41 fT/ Hz at 1 Hz, respectively.