DC current distribution mapping system of the solar panels using a HTS-SQUID gradiometer

NASA Astrophysics Data System (ADS)

Miyazaki, Shingo; Kasuya, Syohei; Mawardi Saari, Mohd; Sakai, Kenji; Kiwa, Toshihiko; Tsukamoto, Akira; Adachi, Seiji; Tanabe, Keiichi; Tsukada, Keiji

2014-05-01

Solar panels are expected to play a major role as a source of sustainable energy. In order to evaluate solar panels, non-destructive tests, such as defect inspections and response property evaluations, are necessary. We developed a DC current distribution mapping system of the solar panels using a High Critical Temperature Superconductor Superconducting Quantum Interference Device (HTS-SQUID) gradiometer with ramp edge type Josephson junctions. Two independent components of the magnetic fields perpendicular to the panel surface (∂Bz/∂x, ∂Bz/∂y) were detected. The direct current of the solar panel is visualized by calculating the composition of the two signal components, the phase angle, and mapping the DC current vector. The developed system can evaluate the uniformity of DC current distributions precisely and may be applicable for defect detection of solar panels.

Superconducting gravity gradiometer for sensitive gravity measurements. I. Theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chan, H.A.; Paik, H.J.

1987-06-15

Because of the equivalence principle, a global measurement is necessary to distinguish gravity from acceleration of the reference frame. A gravity gradiometer is therefore an essential instrument needed for precision tests of gravity laws and for applications in gravity survey and inertial navigation. Superconductivity and SQUID (superconducting quantum interference device) technology can be used to obtain a gravity gradiometer with very high sensitivity and stability. A superconducting gravity gradiometer has been developed for a null test of the gravitational inverse-square law and space-borne geodesy. Here we present a complete theoretical model of this instrument. Starting from dynamical equations for themore » device, we derive transfer functions, a common mode rejection characteristic, and an error model of the superconducting instrument. Since a gradiometer must detect a very weak differential gravity signal in the midst of large platform accelerations and other environmental disturbances, the scale factor and common mode rejection stability of the instrument are extremely important in addition to its immunity to temperature and electromagnetic fluctuations. We show how flux quantization, the Meissner effect, and properties of liquid helium can be utilized to meet these challenges.« less

High-performance dc SQUIDs with submicrometer niobium Josephson junctions

NASA Astrophysics Data System (ADS)

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

1983-11-01

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

SQUIDs De-fluxing Using a Decaying AC Magnetic Field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matlashov, Andrei Nikolaevich; Semenov, Vasili Kirilovich; Anderson, Bill

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

Metallic Contaminant Detection using a High-Temperature Superconducting Quantum Interference Devices Gradiometer

NASA Astrophysics Data System (ADS)

Saburo, Tanaka; Tomohiro, Akai; Makoto, Takemoto; Yoshimi, Hatsukade; Takeyoshi, Ohtani; Yoshio, Ikeda; Shuichi, Suzuki

2010-08-01

We develop magnetic metallic contaminant detectors using high-temperature superconducting quantum interference devices (HTS-SQUIDs) for industrial products. Finding ultra-small metallic contaminants is an important issue for manufacturers producing commercial products such as lithium ion batteries. If such contaminants cause damages, the manufacturer of the product suffers a big financial loss due to having to recall the faulty products. Previously, we described a system for finding such ultra-small particles in food. In this study, we describe further developments of the system, for the reduction of the effect of the remnant field of the products, and we test the parallel magnetization of the products to generate the remnant field only at both ends of the products. In addition, we use an SQUID gradiometer in place of the magnetometer to reduce the edge effect by measuring the magnetic field gradient. We test the performances of the system and find that tiny iron particles as small as 50 × 50 μm2 on the electrode of a lithium ion battery could be clearly detected. This detection level is difficult to achieve when using other methods.

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.

Detection of buried magnetic objects by a SQUID gradiometer system

NASA Astrophysics Data System (ADS)

Meyer, Hans-Georg; Hartung, Konrad; Linzen, Sven; Schneider, Michael; Stolz, Ronny; Fried, Wolfgang; Hauspurg, Sebastian

2009-05-01

We present a magnetic detection system based on superconducting gradiometric sensors (SQUID gradiometers). The system provides a unique fast mapping of large areas with a high resolution of the magnetic field gradient as well as the local position. A main part of this work is the localization and classification of magnetic objects in the ground by automatic interpretation of geomagnetic field gradients, measured by the SQUID system. In accordance with specific features the field is decomposed into segments, which allow inferences to possible objects in the ground. The global consideration of object describing properties and their optimization using error minimization methods allows the reconstruction of superimposed features and detection of buried objects. The analysis system of measured geomagnetic fields works fully automatically. By a given surface of area-measured gradients the algorithm determines within numerical limits the absolute position of objects including depth with sub-pixel accuracy and allows an arbitrary position and attitude of sources. Several SQUID gradiometer data sets were used to show the applicability of the analysis algorithm.

Development of non-destructive evaluation system using an HTS-SQUID gradiometer for magnetized materials

NASA Astrophysics Data System (ADS)

Kawano, J.; Tsukamoto, A.; Adachi, S.; Oshikubo, Y.; Hato, T.; Tanabe, K.; Okamura, T.

We have developed a new eddy-current non-destructive evaluation (NDE) system using an HTS SQUID gradiometer with the aim of applying it to practical materials with magnetization. The new NDE system employs a LN2-cooled external Cu pickup coil and an HTS SQUID chip placed in a magnetic shield made of HTS material. The HTS SQUID chip consists of an HTS planar gradiometer manufactured by using a ramp-edge junction technology and a multi-turn HTS thin film input coil coupled with the flip-chip configuration. The first-order coaxial gradiometric Cu pickup coil with a diameter of 16 mm and the baseline of 5.6 mm was used in the present NDE experiments. By using this NDE system, we could observe defect-induced magnetic signals without an appreciable influence of magnetization up to 10 mT. We also examined the ability of detecting deep-lying defects and compared with the results obtained using our previous NDE system.

Sensors and detectors based on superconducting devices. (Latest citations from the NTIS Bibliographic database). Published Search

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1993-10-01

The bibliography contains citations concerning gradiometers, magnetometers, and infrared detectors which use superconductors to improve sensitivity. Applications include biomagnetic measurements for medical studies, gravity wave experiments, geomagnetism, galvanometers, voltmeters, bolometers and radiometers. Some articles refer to design considerations for cooling systems for the sensors and detectors, and fabrication techniques for SQUIDS (superconducting quantum interference devices). (Contains 250 citations and includes a subject term index and title list.)

Eddy-Current-Based Nondestructive Inspection System Using Superconducting Quantum Interference Device for Thin Copper Tubes

NASA Astrophysics Data System (ADS)

Hatsukade, Yoshimi; Kosugi, Akifumi; Mori, Kazuaki; Tanaka, Saburo

2004-11-01

An eddy-current-based nondestructive inspection (NDI) system using superconducting quantum interference device (SQUID) cooled using a coaxial pulse tube cryocooler was constructed for the inspection of microflaws on copper tubes employing a high-Tc SQUID gradiometer and a Helmholtz-like coil inducer. The detection of artificial flaws several tens of μm in depth on copper tubes 6.35 mm in outer diameter and 0.825 mm in thickness was demonstrated using the SQUID-NDI system. With an excitation field of 1.6 μT at 5 kHz, a 30-μm-depth flaw was successfully detected by the system at an SN ratio of at least 20. The magnetic signal amplitude due to the flaw was proportional to both excitation frequency and the square of flaw depth. With consideration of the system’s sensitivity, the results indicate that sub-10-μm-depth flaws are detectable by the SQUID-NDI system.

SQUID-Detected MRI in the Limit of Zero Static Field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kelso, Nathan Dean

2009-12-14

This thesis describes an implementation of the so-called"zero-field MRI" (ZFMRI) pulse sequence, which allows for imaging in an arbitrarily low B 0 field. The ZFMRI sequence created an effective unidirectional gradient field by using a train of pi pulses to average out the concomitant gradient components during encoding. The signals were acquired using a low-transition temperature dc Superconducting QUantum Interference Device (low-Tc dc SQUID) coupled to a first-order axial gradiometer. The experiments were carried out in a liquid helium dewar which was magnetically shielded with a single-layer mu-metal can around the outside and a superconducting Pb can contained within themore » helium space. We increased the filling factor of the custom-made, double-walled Pyrex insert by placing the liquid alcohol sample, at a temperature of approximately -50 degrees C, at the center of one loop of the superconducting gradiometer, which was immersed in the helium bath.« less

Squids in the Study of Cerebral Magnetic Field

NASA Astrophysics Data System (ADS)

Romani, G. L.; Narici, L.

The following sections are included: * INTRODUCTION * HISTORICAL OVERVIEW * NEUROMAGNETIC FIELDS AND AMBIENT NOISE * DETECTORS * Room temperature sensors * SQUIDs * DETECTION COILS * Magnetometers * Gradiometers * Balancing * Planar gradiometers * Choice of the gradiometer parameters * MODELING * Current pattern due to neural excitations * Action potentials and postsynaptic currents * The current dipole model * Neural population and detected fields * Spherically bounded medium * SPATIAL CONFIGURATION OF THE SENSORS * SOURCE LOCALIZATION * Localization procedure * Experimental accuracy and reproducibility * SIGNAL PROCESSING * Analog Filtering * Bandpass filters * Line rejection filters * DATA ANALYSIS * Analysis of evoked/event-related responses * Simple average * Selected average * Recursive techniques * Similarity analysis * Analysis of spontaneous activity * Mapping and localization * EXAMPLES OF NEUROMAGNETIC STUDIES * Neuromagnetic measurements * Studies on the normal brain * Clinical applications * Epilepsy * Tinnitus * CONCLUSIONS * ACKNOWLEDGEMENTS * REFERENCES

Sensors and detectors based on superconducting devices. (Latest citations from the Compendex database). Published Search

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1993-02-01

The bibliography contains citations concerning gradiometers, magnetometers, and infrared detectors which use superconductors to improve sensitivity. Applications include biomagnetic measurements for medical studies, gravity wave experiments, geomagnetism and ocean bottom magnetic exploration, galvanometers and voltmeters, and bolometers and radiometers. Some articles refer to design considerations for cooling systems for the sensors and detectors, and fabrication techniques for SQUIDS (superconducting quantum interference devices.) (Contains 250 citations and includes a subject term index and title list.)

Development of improved superconductive axial gradiometers for biomagnetic SQUID applications

NASA Astrophysics Data System (ADS)

Budnyk, M. M.; Minov, Yu. D.; Lyakhno, V. Yu.; Desnenko, V. A.; Linnik, A. S.; Shopen, O. B.

2018-03-01

SQUID magnetometers for biomagnetic measurements are equipped with superconductive gradiometers which are required to provide a high signal-to-noise ratio at low frequencies, sufficient mechanical strength and sustained performance under repeated thermal cycles, as well as a low level of intrinsic magnetic noise. This paper describes the design of a gradiometer made with a carbon-fiber reinforced composite material for magnetic cardiography measurements. The thermal coefficient of linear expansion (TCLE) of the carbon fiber composite can be precisely adjusted to match that of the superconducting detector coil wire. This is achieved thanks to the difference in the TCLE of carbon fibers in the longitudinal and transverse directions and is realized by varying the laying directions of the fiber in the composite. The data of magnetic susceptibility measurements on carbon fiber composite are reported, showing the magnetic susceptibility about six times smaller than that of graphite. The presented gradiometer design provides a high degree of balancing and is patented along side other specific techniques.

Sensors and detectors based on superconducting devices. July 1988-June 1989 (Citations from the COMPENDEX data base). Report for July 1988-June 1989

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1989-07-01

This bibliography contains citations concerning gradiometers, magnetometers, and infrared detectors which use superconductors to improve sensitivity. Applications include biomagnetic measurements for medical studies, gravity-wave experiments, geomagnetism and ocean-bottom magnetic exploration, galvanometers and voltmeters, and bolometers and radiometers. Some articles refer to design considerations for cooling systems for the sensors and detectors, and fabrication techniques for SQUIDs (superconducting quantum interference devices.) (This updated bibliography contains 74 citations, all of which are new entries to the previous edition.)

Sensors and detectors based on superconducting devices. January 1970-June 1988 (Citations from the COMPENDEX data base). Report for January 1970-June 1988

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1989-07-01

This bibliography contains citations concerning gradiometers, magnetometers, and infrared detectors which use superconductors to improve sensitivity. Applications include biomagnetic measurements for medical studies, gravity-wave experiments, geomagnetism and ocean-bottom magnetic exploration, galvanometers and voltmeters, and bolometers and radiometers. Some articles refer to design considerations for cooling systems for the sensors and detectors, and fabrication techniques for SQUIDs (superconducting quantum interference devices.) (This updated bibliography contains 394 citations, none of which are new entries to the previous edition.)

Sensors and detectors based on superconducting devices. July 1982-February 1989 (Citations from the EI Engineering Meetings data base). Report for July 1982-February 1989

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1989-04-01

This bibliography contains citations from conference proceedings concerning gradiometers, magnetometers, and infrared detectors which use superconductors to improve sensitivity. Applications include biomagnetic measurements for medical studies, gravity-wave experiments, geomagnetism and ocean bottom magnetic exploration, galvanometers and voltmeters, and bolometers and radiometers. Some articles refer to design considerations for cooling systems for the sensors and detectors, and fabrication techniques for SQUIDS (superconducting quantum interference devices.) (Contains 115 citations fully indexed and including a title list.)

Sensors and detectors based on superconducting devices. January 1970-June 1988 (Citations from the Engineering Index data base). Report for January 1970-June 1988

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1988-07-01

This bibliography contains citations concerning gradiometers, magnetometers, and infrared detectors which use superconductors to improve sensitivity. Applications include biomagnetic measurements for medical studies, gravity-wave experiments, geomagnetism, and ocean-bottom magnetic exploration, galvanometers and voltmeters, and bolometers, and radiometers. Some articles refer to design considerations for cooling systems for the sensors and detectors, and fabrication techniques for squids (superconducting quantum interference devices.) (This updated bibliography contains 394 citations, 71 of which are new entries to the previous edition.)

MCG measurement in the environment of active magnetic shield.

PubMed

Yamazaki, K; Kato, K; Kobayashi, K; Igarashi, A; Sato, T; Haga, A; Kasai, N

2004-11-30

MCG (Magnetocardiography) measurement by a SQUID gradiometer was attempted with only active magnetic shielding (active shielding). A three-axis-canceling-coil active shielding system, where three 16-10-16 turns-coil sets were put in the orthogonal directions, produces a homogeneous magnetic field in a considerable volume surrounding the center. Fluxgate sensors were used as the reference sensors of the system. The system can reduce environmental magnetic noise at low frequencies of less than a few Hz, at 50 Hz and at 150 Hz. Reducing such disturbances stabilizes biomagnetic measurement conditions for SQUIDs in the absence of magnetically shielded rooms (MSR). After filtering and averaging the measured MCG data by a first-order SQUID gradiometer with only the active shielding during the daytime, the QRS complex and T wave was clearly presented.

Potential applications of microtesla magnetic resonance imaging detected using a superconducting quantum interference device

NASA Astrophysics Data System (ADS)

Myers, Whittier Ryan

This dissertation describes magnetic resonance imaging (MRI) of protons performed in a precession field of 132 muT. In order to increase the signal-to-noise ratio (SNR), a pulsed 40-300 mT magnetic field prepolarizes the sample spins and an untuned second-order superconducting gradiometer coupled to a low transition temperature superconducting quantum interference device (SQUID) detects the subsequent 5.6-kHz spin precession. Imaging sequences including multiple echoes and partial Fourier reconstruction are developed. Calculating the SNR of prepolarized SQUID-detected MRI shows that three-dimensional Fourier imaging yields higher SNR than slice-selection imaging. An experimentally demonstrated field-cycling pulse sequence and post-processing algorithm mitigate image artifacts caused by concomitant gradients in low-field MRI. The magnetic field noise of SQUID untuned detection is compared to the noise of SQUID tuned detection, conventional Faraday detection, and the Nyquist noise generated by conducting biological samples. A second-generation microtesla MRI system employing a low-noise SQUID is constructed to increase SNR. A 2.4-m cubic, eddy-current shield with 6-mm thick aluminum walls encloses the experiment to attenuate external noise. The measured noise is 0.75 fT Hz 1/2 referred to the bottom gradiometer loop. Solenoids wound from 30-strand braided wire to decrease Nyquist noise and cooled by either liquid nitrogen or water polarize the spins. Copper wire coils wound on wooden supports produce the imaging magnetic fields and field gradients. Water phantom images with 0.8 x 0.8 x 10 mm3 resolution have a SNR of 6. Three-dimensional 1.6 x 1.9 x 14 mm3 images of bell peppers and 3 x 3 x 26 mm3 in vivo images of the human arm are presented. Since contrast based on the transverse spin relaxation rate (T1 ) is enhanced at low magnetic fields, microtesla MRI could potentially be used for tumor imaging. The measured T1 of ex vivo normal and cancerous prostate tissue differ significantly at 132 muT. A single-sided MRI system designed for prostate imaging could achieve 3 x 3 x 5 mm3 resolution in 8 minutes. Existing SQUID-based magnetoencephalography (MEG) systems could be used as microtesla MRI detectors. A commercial 275-channel MEG system could acquire 6-minute brain images with (4 mm)3 resolution and SNR 16.

Sensors and detectors based on superconducting devices. July 1982-May 1990 (A Bibliography from the EI Engineering Meetings data base). Report for July 1982-May 1990

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1990-06-01

This bibliography contains citations from conference proceedings concerning gradiometers, magnetometers, and infrared detectors which use superconductors to improve sensitivity. Applications include biomagnetic measurements for medical studies, gravity wave experiments, geomagnetism and ocean bottom magnetic exploration, galvanometers and voltmeters, and bolometers and radiometers. Some articles refer to design considerations for cooling systems for the sensors and detectors, and fabrication techniques for squids (superconducting quantum interference devices.) (This updated bibliography contains 189 citations, 74 of which are new entries to the previous edition.)

Low-Tc direct current superconducting quantum interference device magnetometer-based 36-channel magnetocardiography system in a magnetically shielded room

NASA Astrophysics Data System (ADS)

Qiu, Yang; Li, Hua; Zhang, Shu-Lin; Wang, Yong-Liang; Kong, Xiang-Yan; Zhang, Chao-Xiang; Zhang, Yong-Sheng; Xu, Xiao-Feng; Yang, Kang; Xie, Xiao-Ming

2015-07-01

We constructed a 36-channel magnetocardiography (MCG) system based on low-Tc direct current (DC) superconducting quantum interference device (SQUID) magnetometers operated inside a magnetically shielded room (MSR). Weakly damped SQUID magnetometers with large Steward-McCumber parameter βc (βc ≈ 5), which could directly connect to the operational amplifier without any additional feedback circuit, were used to simplify the readout electronics. With a flux-to-voltage transfer coefficient ∂ V/∂ Φ larger than 420 μV/Φ 0, the SQUID magnetometers had a white noise level of about 5.5 fT·Hz-1/2 when operated in MSR. 36 sensing magnetometers and 15 reference magnetometers were employed to realize software gradiometer configurations. The coverage area of the 36 sensing magnetometers is 210×210 mm2. MCG measurements with a high signal-to-noise ratio of 40 dB were done successfully using the developed system. Project supported by “One Hundred Persons Project” of the Chinese Academy of Sciences and the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (Grant No. XDB04020200).

Basic and Applied Magnetism with a Squid Gradiometer.

DTIC Science & Technology

1985-12-01

r , , WV w- =v- -V,; . r Zr! I , : r -. : r , : s : i . : I , C CI SQUID ta) 0 7 - .- 4 , 4 4 4 - .44* . . 2 Te 1 I T ...... 2zt 14 tbt’faceewient...incheS) iuSteed D~ISPLACE4ENT ’ . • •. . , I t ( pi A, , I phud.I’ t h bh r . /Os ,7/,/( ds I DR8 _ I Is i it r V( ttw( lt hd ,h r % I I VS94 SQUID...magnetization. Barkhausen Reversible Missing

A high-temperature rf SQUID system for magnetocardiography

NASA Astrophysics Data System (ADS)

Zeng, X. H.; Soltner, H.; Selbig, D.; Bode, M.; Bick, M.; Rüders, F.; Schubert, J.; Zander, W.; Banzet, M.; Zhang, Y.; Bousack, H.; Braginski, A. I.

1998-09-01

A first-order axial electronic gradiometer having a baseline of 10 cm was constructed by assembling two 0957-0233/9/9/033/img15 rf SQUID magnetometers with coplanar tank resonators, each having a white magnetic field resolution of about 0957-0233/9/9/033/img16 at 77 K. The gradiometer's near-field resolution was about 0957-0233/9/9/033/img17, including the Dewar flask's noise. A peak-to-peak noise level of 3 pT was obtained in the bandwidth 0.016-250 Hz. Magnetocardiographic (MCG) measurements were performed using this bandwidth. Measurements on human subjects have been conducted in a magnetically shielded room of moderate shielding factor. Using the signal either of the lower magnetometer or of the gradiometer, high-quality heart signal traces could be collected, which were suitable for diagnostic use. A team of physicians, assisted by two of the authors, used the equipment over 10 months to perform MCG measurements in a medical study of about 80 clinical patients with cardiac arrhythmia problems and healthy persons. The system's performance was stable over that whole period.

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.

Obituary: Gordon Donaldson Obituary: Gordon Donaldson

NASA Astrophysics Data System (ADS)

Pegrum, Colin; Campbell, Archie; Hampshire, Damian

2013-07-01

Gordon Donaldson died in Glasgow on 28 November 2012 at the age of 71. He was born in Edinburgh and brought up and educated in Glasgow, which was his home city for much of his life. He was educated first at Glasgow Academy, and then with a scholarship at Christ's College Cambridge. Here he read Natural Sciences, finishing with first class honors in Physics. He then did a PhD on tunneling in superconductors in the Mond Laboratory, supervised by John Adkins. These were interesting times, since type II superconductors had only recently been identified, and the Mond was a leading player in the physics of vortices and other quantum effects. It was headed by Pippard and Shoenberg, and colleagues around that time were Brian Josephson, John Clarke, Colin Gough and John Waldram. On finishing his PhD in 1966 Gordon went straight to a lectureship at the University of Lancaster. In 1975 during a sabbatical at the University of California, Berkeley, with John Clarke's group, Gordon co-invented thin-film gradiometers with integrated DC SQUIDs. He then moved back to Glasgow, to the Department of Applied Physics at Strathclyde University, where he founded a new research group to make and use superconducting devices, especially SQUIDs and gradiometers. From modest beginnings the group grew steadily, acquiring new facilities and members, until in the 1990s it had over 20 members and a host of collaborators from elsewhere in Glasgow and abroad. With funding from the Wellcome Trust, Gordon and colleagues at Glasgow University and the Southern General Hospital in Glasgow set up a new biomagnetism facility in 1998 on the hospital campus to use SQUID gradiometers made at Strathclyde for measurements on patients and volunteers. Another of his main research interests was the use of SQUIDs for nondestructive evaluation (NDE). This started in the days before high temperature superconductors (HTS) with wire-wound gradiometers and niobium SQUIDs, soon moving on to miniature thin-film niobium integrated SQUID gradiometers. This was followed by major programs to develop and demonstrate HTS gradiometers for NDE. Gordon was appointed to a personal professorship in 1985 and became Professor of Applied Physics two years later. He was also head of department from 1984 to 1986 and again from 1993 to 1998. He was a Fellow of the Royal Society of Edinburgh and became Convener of their Physics Panel. He was also a Trustee of the James Clerk Maxwell Foundation. Gordon was much involved in teaching and in many university matters. He was particularly fond of the course How Things Work, which he developed and taught for fifteen years, that was so much in keeping with his passion for useful practical physics and science. After the explosion in HTS research, Gordon became the Coordinator for the National Committee for Superconductivity in the UK for three years from 1990. One of his important tasks was to coordinate the distribution of EPSRC funds to university groups and to support industrial activity. He did this with tact and good judgment. He knew everybody, understood what they were doing, and made sure that while the large groups were well supported, nobody was left out completely. This exercise could have led to resentment, but under his guidance it was a great success and it is a pity that similar exercises have not been tried since. He was a key member of the Low Temperature Group of the Institute of Physics in London, and became its Chairman for the last three years of his tenure. In 1998, he was invited to become editor of Superconductor Science and Technology (SuST). He was a referee for every paper in the journal during this period, which was an enormous task and very widely appreciated by the superconductivity community. He was particularly active during the discovery and commercialization of MgB2. He oversaw a smooth handover to his successor as Editor-in-Chief in 2007. Gordon's long list of publications and contributions to books attest to his advancement of superconducting technology. He will be especially remembered as an independent originator of nondestructive evaluation (NDE) of materials and structures using SQUIDs, and for the advancement and use of the gradiometers developed at Berkeley for biomagnetic use. He organized and chaired two key conferences, the International Superconductive Electronics Conference in Glasgow in 1991 and then the 1995 European Conference on Applied Superconductivity in Edinburgh, together with many smaller specialist meetings. Since he retired he was afflicted with severe back problems, and unfortunately operations were not successful. He was confined to a wheelchair and later to the house, which was a great trial to him. Gordon was universally respected and liked both as a scientist and a person. He was sharp, humorous and excellent company on social occasions. He will be much missed by his many colleagues and friends at SuST and throughout science, as well as by his family.

SQUID use for Geophysics: finding billions of dollars

NASA Astrophysics Data System (ADS)

Foley, Catherine

2014-03-01

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

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.

A high- Tc SQUID-based sensor head cooled by a Joule-Thomson cryocooler

NASA Astrophysics Data System (ADS)

Rijpma, A. P.; ter Brake, H. J. M.; de Vries, E.; Nijhof, N.; Holland, H. J.; Rogalla, H.

2002-08-01

The goal of the so-called FHARMON project is to develop a high- Tc SQUID-based magnetometer system for the measurement of fetal heart activity in standard clinical environments. To lower the threshold for the application of this fetal heart monitor, it should be simple to operate. It is, therefore, advantageous to replace the liquid cryogen bath by a closed-cycle refrigerator. For this purpose, we selected a mixed-gas Joule-Thomson cooler; the APD Cryotiger ©. Because of its magnetic interference, the compressor of this closed-cycle cooler will be placed at a distance of ≈2 m from the actual sensor, which is an axial second order gradiometer. The gradiometer is formed by three magnetometers placed on an alumina cylinder, which is connected to the cold head of the cooler. This paper describes the sensor head in detail and reports on test experiments.

Measuring MEG closer to the brain: Performance of on-scalp sensor arrays

PubMed Central

Iivanainen, Joonas; Stenroos, Matti; Parkkonen, Lauri

2017-01-01

Optically-pumped magnetometers (OPMs) have recently reached sensitivity levels required for magnetoencephalography (MEG). OPMs do not need cryogenics and can thus be placed within millimetres from the scalp into an array that adapts to the invidual head size and shape, thereby reducing the distance from cortical sources to the sensors. Here, we quantified the improvement in recording MEG with hypothetical on-scalp OPM arrays compared to a 306-channel state-of-the-art SQUID array (102 magnetometers and 204 planar gradiometers). We simulated OPM arrays that measured either normal (nOPM; 102 sensors), tangential (tOPM; 204 sensors), or all components (aOPM; 306 sensors) of the magnetic field. We built forward models based on magnetic resonance images of 10 adult heads; we employed a three-compartment boundary element model and distributed current dipoles evenly across the cortical mantle. Compared to the SQUID magnetometers, nOPM and tOPM yielded 7.5 and 5.3 times higher signal power, while the correlations between the field patterns of source dipoles were reduced by factors of 2.8 and 3.6, respectively. Values of the field-pattern correlations were similar across nOPM, tOPM and SQUID gradiometers. Volume currents reduced the signals of primary currents on average by 10%, 72% and 15% in nOPM, tOPM and SQUID magnetometers, respectively. The information capacities of the OPM arrays were clearly higher than that of the SQUID array. The dipole-localization accuracies of the arrays were similar while the minimum-norm-based point-spread functions were on average 2.4 and 2.5 times more spread for the SQUID array compared to nOPM and tOPM arrays, respectively. PMID:28007515

Optimization of pick-up coils for weakly damped SQUID gradiometers

NASA Astrophysics Data System (ADS)

Yang, Kang; Wang, Jialei; Kong, Xiangyan; Yang, Ruihu; Chen, Hua

2018-05-01

Not Available Project supported by the Key Project of Shanghai Zhangjiang National Innovation Demonstration Zone of the Special Development Fund, China (Grant No. 2015-JD-C104-060) and the National Natural Science Foundation of China (Grant No. 61741122).

Application of the double relaxation oscillation superconducting quantum interference device sensor to micro-tesla 1H nuclear magnetic resonance experiments

NASA Astrophysics Data System (ADS)

Kang, Chan Seok; Kim, Kiwoong; Lee, Seong-Joo; Hwang, Seong-min; Kim, Jin-Mok; Yu, Kwon Kyu; Kwon, Hyukchan; Lee, Sang Kil; Lee, Yong-Ho

2011-09-01

We developed an ultra-low field (ULF)-nuclear magnetic resonance (NMR) measurement system capable of working with a measurement field (Bm) of several micro-tesla and performed basic NMR studies with a double relaxation oscillation superconducting quantum interference device (DROS) instead of conventional dc-SQUIDs. DROS is a SQUID sensor utilizing a relaxation oscillation between a dc-SQUID and a relaxation circuit; the new unit consists of an inductor and a resistor, and is connected in parallel with the SQUID. DROS has a 10 times larger flux-to-voltage transfer coefficient (˜mV/ϕ0) than that of the dc-SQUID, and this large transfer coefficient enables the acquisition of the SQUID signal with a simple flux-locked-loop (FLL) circuit using room temperature pre-amplifiers. The DROS second-order gradiometer showed average field noise of 9.2 μϕ0/√Hz in a magnetically shielded room (MSR). In addition, a current limiter formed of a Josephson junction array was put in a flux-transformer of DROS to prevent excessive currents that can be generated from the high pre-polarization field (Bp). Using this system, we measured an 1H NMR signal in water under 2.8 μT Bm field and reconstructed a one-dimensional MR image from the 1H NMR signal under a gradient field BG of 4.09 nT/mm. In addition, we confirmed that the ULF-NMR system can measure the NMR signal in the presence of metal without any distortion by measuring the NMR signal of a sample wrapped with metal. Lastly, we have measured the scalar J-coupling of trimethylphosphate and were able to confirm a clear doublet NMR signal with the coupling strength J3[P,H] = 10.4 ± 0.8 Hz. Finally, because the existing ULF-NMR/MRI studies were almost all performed with dc-SQUID based systems, we constructed a dc-SQUID-based ULF-NMR system in addition to the DROS based system and compared the characteristics of the two different systems by operating the two systems under identical experimental conditions.

Magnetic cooling for microkelvin nanoelectronics on a cryofree platform.

PubMed

Palma, M; Maradan, D; Casparis, L; Liu, T-M; Froning, F N M; Zumbühl, D M

2017-04-01

We present a parallel network of 16 demagnetization refrigerators mounted on a cryofree dilution refrigerator aimed to cool nanoelectronic devices to sub-millikelvin temperatures. To measure the refrigerator temperature, the thermal motion of electrons in a Ag wire-thermalized by a spot-weld to one of the Cu nuclear refrigerators-is inductively picked-up by a superconducting gradiometer and amplified by a SQUID mounted at 4 K. The noise thermometer as well as other thermometers are used to characterize the performance of the system, finding magnetic field independent heat-leaks of a few nW/mol, cold times of several days below 1 mK, and a lowest temperature of 150 μK of one of the nuclear stages in a final field of 80 mT, close to the intrinsic SQUID noise of about 100 μK. A simple thermal model of the system capturing the nuclear refrigerator, heat leaks, and thermal and Korringa links describes the main features very well, including rather high refrigerator efficiencies typically above 80%.

Recent advancements in the SQUID magnetospinogram system

NASA Astrophysics Data System (ADS)

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

2017-06-01

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

Study on nondestructive inspection using HTS-SQUID for friction stir welding between dissimilar metals

NASA Astrophysics Data System (ADS)

Hatsukade, Y.; Takahashi, T.; Yasui, T.; Tsubaki, M.; Fukumono, M.; Tanaka, S.

2007-10-01

We have developed an SQUID-NDI technique for evaluation of friction stir welding (FSW) between aluminum alloy A6063 and stainless steel SUS304 from the electric conductivities in board specimens bonded by FSW. A SQUID-NDI system employing an HTS-SQUID gradiometer was constructed to measure current distribution in the FSW specimens by applying voltage to the specimen. By measuring field gradients dBz/dy and dBz/dx above the FSW specimens made with various FSW conditions and then converting them to current vector Jx and Jy, conductivities of FSW areas were estimated. Due to the difference in the FSW conditions, the conductivity distributions varied dramatically. From these results, it was suggested that the conductivities in FSW areas should be varied due to the temperature heated by the friction between the milling tool and the materials.

Correcting Concomitant Gradient Distortion in Microtesla Magnetic Resonance Imaging

NASA Astrophysics Data System (ADS)

Myers, Whittier

2005-03-01

Progress in ultra-low field magnetic resonance imaging (MRI) using an untuned gradiometer coupled to a Superconducting Quantum Interference Device (SQUID) has resulted in three-dimensional images with an in-plane resolution of 2 mm. Protons in samples up to 80 mm in size were prepolarized in a 100 mT field, manipulated by ˜100 μT/m gradients for image encoding, and detected by the SQUID in the ˜65 μT precession field. Maxwell's equations prohibit a unidirectional magnetic field gradient. While the additional concomitant gradients can be neglected in high-field MRI, they distort high-resolution images of large samples taken in microtesla precession fields. We propose two methods to mitigate such distortion: raising the precession field during image encoding, and software post-processing. Both approaches are demonstrated using computer simulations and MRI images. Simulations show that the combination of these techniques can correct the concomitant gradient distortion present in a 4-mm resolution image of an object the size of a human brain with a precession field of 50 μT. Supported by USDOE.

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.

Magnetic biosensor using a high transition temperature SQUID

NASA Astrophysics Data System (ADS)

Grossman, Helene Lila

A high transition temperature (Tc) Superconducting QUantum Interference Device (SQUID) is used to detect magnetically-labeled microorganisms. The targets are identified and quantified by means of magnetic relaxation measurements, with no need for unbound magnetic labels to be washed away. The binding rate between antibody-linked magnetic particles and targets can be measured with this technique. Installed in a "SQUID microscope," a YBa2Cu 3O7-delta SQUID is mounted on a sapphire rod thermally linked to a liquid nitrogen can; these components are enclosed in a fiberglass vacuum chamber. A thin window separates the vacuum chamber from the sample, which is at room temperature and atmospheric pressure. In one mode of the experiment, targets are immobilized on a substrate and immersed a suspension of ˜50 nm diameter superparamagnetic particles, coated with antibodies. A pulsed magnetic field aligns the magnetic dipole moments, and the SQUID measures the magnetic relaxation signal each time the field is turned off. Unbound particles relax within ˜50 mus by Brownian rotation, too fast for the SQUID system to measure. In contrast, particles bound to targets have their Brownian motion inhibited. These particles relax in ˜1 s by rotation of the internal dipole moment, and this Neel relaxation process is detected by the SQUID. This assay is demonstrated with a model system of liposomes carrying the FLAG epitope; the detection limit is (2.7 +/- 0.2) x 105 particles. The replacement of the SQUID with a gradiometer improves the detection limit to (7.0 +/- 0.7) x 103 particles. In an alternate mode of the experiment, freely suspended targets (larger than ˜1 mum diameter) are detected. Since the Brownian relaxation time of the targets is longer than the measurement time, particles bound to targets are effectively immobilized and exhibit Neel relaxation. Listeria monocytogenes are detected using this method; the sensitivity is (1.1 +/- 0.2) x 105 bacteria in 20 muL. For a 1 nL sample volume, the detection limit is expected to be 230 +/- 40 bacteria. Time-resolved measurements, which yield the binding rate between particles and bacteria, are reported. Also, potential improvements to the system and possible applications are discussed.

Statistical characterization of voltage-biased SQUIDs with weakly damped junctions

NASA Astrophysics Data System (ADS)

Liu, Chao; Zhang, Yi; Mück, Michael; Zhang, Shulin; Krause, Hans-Joachim; Braginski, Alex I.; Zhang, Guofeng; Wang, Yongliang; Kong, Xiangyan; Xie, Xiaoming; Offenhäusser, Andreas; Jiang, Mianheng

2013-06-01

Recently, it has been shown that voltage-biased readout of SQUIDs with weakly damped junctions (large Stewart-McCumber parameter βc, due to high shunt resistance) is useful for suppression of preamplifier noise. We experimentally studied the characteristics of 53 planar niobium-SQUID magnetometers with junction shunt resistors RJ nominally of 30 Ω fabricated on 5 × 5 mm2 chips. The field-to-flux transfer coefficient ∂B/∂Φ of the magnetometers was 1.5 nT/Φ0, with a SQUID loop inductance Ls of about 350 pH. The distributions of important SQUID parameters, such as the current swing Iswing, the dynamic resistance Rd, and the flux-to-voltage transfer coefficient ∂V/∂Φ, are given. Nearly all the SQUIDs could be stably operated in the voltage bias mode and their ∂V/∂Φ reached a large mean value of 380 μV/Φ0. In this case, the SQUIDs can be read out directly by a commercial operational amplifier without any additional means to suppress preamplifier noise. The mean flux noise of the SQUIDs was found to be 4.5 μΦ0 Hz-1/2, corresponding to a field resolution of 7 fT Hz-1/2. To demonstrate the applicability of these SQUIDs in the direct readout scheme, a simple four-channel SQUID gradiometer system was set up to perform magnetocardiography and magnetoencephalography measurements in a magnetically shielded room.

Superconducting gravity gradiometer and a test of inverse square law

NASA Technical Reports Server (NTRS)

Moody, M. V.; Paik, Ho Jung

1989-01-01

The equivalence principle prohibits the distinction of gravity from acceleration by a local measurement. However, by making a differential measurement of acceleration over a baseline, platform accelerations can be cancelled and gravity gradients detected. In an in-line superconducting gravity gradiometer, this differencing is accomplished with two spring-mass accelerometers in which the proof masses are confined to motion in a single degree of freedom and are coupled together by superconducting circuits. Platform motions appear as common mode accelerations and are cancelled by adjusting the ratio of two persistent currents in the sensing circuit. The sensing circuit is connected to a commercial SQUID amplifier to sense changes in the persistent currents generated by differential accelerations, i.e., gravity gradients. A three-axis gravity gradiometer is formed by mounting six accelerometers on the faces of a precision cube, with the accelerometers on opposite faces of the cube forming one of three in-line gradiometers. A dedicated satellite mission for mapping the earth's gravity field is an important one. Additional scientific goals are a test of the inverse square law to a part in 10(exp 10) at 100 km, and a test of the Lense-Thirring effect by detecting the relativistic gravity magnetic terms in the gravity gradient tensor for the earth.

Joint geophysical investigation of a small scale magnetic anomaly near Gotha, Germany

NASA Astrophysics Data System (ADS)

Queitsch, Matthias; Schiffler, Markus; Goepel, Andreas; Stolz, Ronny; Guenther, Thomas; Malz, Alexander; Meyer, Matthias; Meyer, Hans-Georg; Kukowski, Nina

2014-05-01

In the framework of the multidisciplinary project INFLUINS (INtegrated FLUid Dynamics IN Sedimentary Basins) several airborne surveys using a full tensor magnetic gradiometer (FTMG) system were conducted in and around the Thuringian basin (central Germany). These sensors are based on highly sensitive superconducting quantum interference devices (SQUIDs) with a planar-type gradiometer setup. One of the main goals was to map magnetic anomalies along major fault zones in this sedimentary basin. In most survey areas low signal amplitudes were observed caused by very low magnetization of subsurface rocks. Due to the high lateral resolution of a magnetic gradiometer system and a flight line spacing of only 50m, however, we were able to detect even small magnetic lineaments. Especially close to Gotha a NW-SE striking strong magnetic anomaly with a length of 1.5 km was detected, which cannot be explained by the structure of the Eichenberg-Gotha-Saalfeld (EGS) fault zone and the rock-physical properties (low susceptibilities). Therefore, we hypothesize that the source of the anomaly must be related to an anomalous magnetization in the fault plane. To test this hypothesis, here we focus on the results of the 3D inversion of the airborne magnetic data set and compare them with existing structural geological models. In addition, we conducted several ground based measurements such as electrical resistivity tomography (ERT) and frequency domain electromagnetics (FDEM) to locate the fault. Especially, the geoelectrical measurements were able to image the fault zone. The result of the 2D electrical resistivity tomography shows a lower resistivity in the fault zone. Joint interpretation of airborne magnetics, geoelectrical and geological information let us propose that the source of the magnetization may be a fluid-flow induced impregnation with iron-oxide bearing minerals in the vicinity of the EGS fault plane.

Airborne full tensor magnetic gradiometry surveys in the Thuringian basin, Germany

NASA Astrophysics Data System (ADS)

Queitsch, M.; Schiffler, M.; Goepel, A.; Stolz, R.; Meyer, M.; Meyer, H.; Kukowski, N.

2013-12-01

In this contribution we introduce a newly developed fully operational full tensor magnetic gradiometer (FTMG) instrument based on Superconducting Quantum Interference Devices (SQUIDs) and show example data acquired in 2012 within the framework of the INFLUINS (Integrated Fluid Dynamics in Sedimentary basins) project. This multidisciplinary project aims for a better understanding of movements and interaction between shallow and deep fluids in the Thuringian Basin in the center of Germany. In contrast to mapping total magnetic field intensity (TMI) in conventional airborne magnetic surveys for industrial exploration of mineral deposits and sedimentary basins, our instrument measures all components of the magnetic field gradient tensor using highly sensitive SQUID gradiometers. This significantly constrains the solutions of the inverse problem. Furthermore, information on the ratio between induced and remanent magnetization is obtained. Special care has been taken to reduce motion noise while acquiring data in airborne operation. Therefore, the sensors are mounted in a nonmagnetic and aerodynamically shaped bird made of fiberglas with a high drag tail which stabilizes the bird even at low velocities. The system is towed by a helicopter and kept at 30m above ground during data acquisition. Additionally, the system in the bird incorporates an inertial unit for geo-referencing and enhanced motion noise compensation, a radar altimeter for topographic correction and a GPS system for high precision positioning. Advanced data processing techniques using reference magnetometer and inertial unit data result in a very low system noise of less than 60 pT/m peak to peak in airborne operation. To show the performance of the system we present example results from survey areas within the Thuringian basin and along its bordering highlands. The mapped gradient tensor components show a high correlation to existing geologic maps. Furthermore, the measured gradient components indicate that some of the observed magnetic anomalies have a strong remanent magnetization. One example of interpretation of the acquired data of a magnetic anomaly related to a larger gabbro formation is presented.

Magnetoencephalographic accuracy profiles for the detection of auditory pathway sources.

PubMed

Bauer, Martin; Trahms, Lutz; Sander, Tilmann

2015-04-01

The detection limits for cortical and brain stem sources associated with the auditory pathway are examined in order to analyse brain responses at the limits of the audible frequency range. The results obtained from this study are also relevant to other issues of auditory brain research. A complementary approach consisting of recordings of magnetoencephalographic (MEG) data and simulations of magnetic field distributions is presented in this work. A biomagnetic phantom consisting of a spherical volume filled with a saline solution and four current dipoles is built. The magnetic fields outside of the phantom generated by the current dipoles are then measured for a range of applied electric dipole moments with a planar multichannel SQUID magnetometer device and a helmet MEG gradiometer device. The inclusion of a magnetometer system is expected to be more sensitive to brain stem sources compared with a gradiometer system. The same electrical and geometrical configuration is simulated in a forward calculation. From both the measured and the simulated data, the dipole positions are estimated using an inverse calculation. Results are obtained for the reconstruction accuracy as a function of applied electric dipole moment and depth of the current dipole. We found that both systems can localize cortical and subcortical sources at physiological dipole strength even for brain stem sources. Further, we found that a planar magnetometer system is more suitable if the position of the brain source can be restricted in a limited region of the brain. If this is not the case, a helmet-shaped sensor system offers more accurate source estimation.

Induced electric currents in the Alaska oil pipeline measured by gradient, fluxgate, and SQUID magnetometers

NASA Technical Reports Server (NTRS)

Campbell, W. H.; Zimmerman, J. E.

1979-01-01

The field gradient method for observing the electric currents in the Alaska pipeline provided consistent values for both the fluxgate and SQUID method of observation. These currents were linearly related to the regularly measured electric and magnetic field changes. Determinations of pipeline current were consistent with values obtained by a direct connection, current shunt technique at a pipeline site about 9.6 km away. The gradient method has the distinct advantage of portability and buried- pipe capability. Field gradients due to the pipe magnetization, geological features, or ionospheric source currents do not seem to contribute a measurable error to such pipe current determination. The SQUID gradiometer is inherently sensitive enough to detect very small currents in a linear conductor at 10 meters, or conversely, to detect small currents of one amphere or more at relatively great distances. It is fairly straightforward to achieve imbalance less than one part in ten thousand, and with extreme care, one part in one million or better.

Three-Axis Superconducting Gravity Gradiometer

NASA Technical Reports Server (NTRS)

Paik, Ho Jung

1987-01-01

Gravity gradients measured even on accelerating platforms. Three-axis superconducting gravity gradiometer based on flux quantization and Meissner effect in superconductors and employs superconducting quantum interference device as amplifier. Incorporates several magnetically levitated proof masses. Gradiometer design integrates accelerometers for operation in differential mode. Principal use in commercial instruments for measurement of Earth-gravity gradients in geo-physical surveying and exploration for oil.

Superconducting tensor gravity gradiometer for satellite geodesy and inertial navigation

NASA Technical Reports Server (NTRS)

Paik, H. J.

1981-01-01

A sensitive gravity gradiometer can provide much needed gravity data of the earth and improve the accuracy of inertial navigation. Superconductivity and other properties of materials at low temperatures can be used to obtain a sensitive, low-drift gravity gradiometer; by differencing the outputs of accelerometer pairs using superconducting circuits, it is possible to construct a tensor gravity gradiometer which measures all the in-line and cross components of the tensor simultaneously. Additional superconducting circuits can be provided to determine the linear and angular acceleration vectors. A tensor gravity gradiometer with these features is being developed for satellite geodesy. The device constitutes a complete package of inertial navigation instruments with angular and linear acceleration readouts as well as gravity signals.

Choice of Magnetometers and Gradiometers after Signal Space Separation.

PubMed

Garcés, Pilar; López-Sanz, David; Maestú, Fernando; Pereda, Ernesto

2017-12-16

Modern Elekta Neuromag MEG devices include 102 sensor triplets containing one magnetometer and two planar gradiometers. The first processing step is often a signal space separation (SSS), which provides a powerful noise reduction. A question commonly raised by researchers and reviewers relates to which data should be employed in analyses: (1) magnetometers only, (2) gradiometers only, (3) magnetometers and gradiometers together. The MEG community is currently divided with regard to the proper answer. First, we provide theoretical evidence that both gradiometers and magnetometers result from the backprojection of the same SSS components. Then, we compare resting state and task-related sensor and source estimations from magnetometers and gradiometers in real MEG recordings before and after SSS. SSS introduced a strong increase in the similarity between source time series derived from magnetometers and gradiometers (r² = 0.3-0.8 before SSS and r² > 0.80 after SSS). After SSS, resting state power spectrum and functional connectivity, as well as visual evoked responses, derived from both magnetometers and gradiometers were highly similar (Intraclass Correlation Coefficient > 0.8, r² > 0.8). After SSS, magnetometer and gradiometer data are estimated from a single set of SSS components (usually ≤ 80). Equivalent results can be obtained with both sensor types in typical MEG experiments.

Unshielded fetal magnetocardiography system using two-dimensional gradiometers

NASA Astrophysics Data System (ADS)

Seki, Yusuke; Kandori, Akihiko; Kumagai, Yukio; Ohnuma, Mitsuru; Ishiyama, Akihiko; Ishii, Tetsuko; Nakamura, Yoshiyuki; Horigome, Hitoshi; Chiba, Toshio

2008-03-01

We developed a fetal magnetocardiography (fMCG) system that uses a pair of two-dimensional gradiometers to achieve high signal-to-noise ratio. The gradiometer, which is based on a low-Tc superconducting quantum interference device, detects the gradient of a magnetic field in two orthogonal directions. Gradiometer position is easy to adjust by operating the gantry to drive the cryostat in both the swinging and axial directions. As a result, a fMCG waveform for 25weeks' gestation was measured under an unshielded environment in real time. Moreover, the P and T waves for 25 and 34weeks' gestation, respectively, were obtained by averaging. These results indicate that this two-dimensional gradiometer is one of the most promising techniques for measuring fetal heart rate and diagnosing fetal arrhythmia.

Adaptive suppression of power line interference in ultra-low field magnetic resonance imaging in an unshielded environment

NASA Astrophysics Data System (ADS)

Huang, Xiaolei; Dong, Hui; Qiu, Yang; Li, Bo; Tao, Quan; Zhang, Yi; Krause, Hans-Joachim; Offenhäusser, Andreas; Xie, Xiaoming

2018-01-01

Power-line harmonic interference and fixed-frequency noise peaks may cause stripe-artifacts in ultra-low field (ULF) magnetic resonance imaging (MRI) in an unshielded environment and in a conductively shielded room. In this paper we describe an adaptive suppression method to eliminate these artifacts in MRI images. This technique utilizes spatial correlation of the interference from different positions, and is realized by subtracting the outputs of the reference channel(s) from those of the signal channel(s) using wavelet analysis and the least squares method. The adaptive suppression method is first implemented to remove the image artifacts in simulation. We then experimentally demonstrate the feasibility of this technique by adding three orthogonal superconducting quantum interference device (SQUID) magnetometers as reference channels to compensate the output of one 2nd-order gradiometer. The experimental results show great improvement in the imaging quality in both 1D and 2D MRI images at two common imaging frequencies, 1.3 kHz and 4.8 kHz. At both frequencies, the effective compensation bandwidth is as high as 2 kHz. Furthermore, we examine the longitudinal relaxation times of the same sample before and after compensation, and show that the MRI properties of the sample did not change after applying adaptive suppression. This technique can effectively increase the imaging bandwidth and be applied to ULF MRI detected by either SQUIDs or Faraday coil in both an unshielded environment and a conductively shielded room.

Using unmanned aerial vehicle-borne magnetic sensors to detect and locate improvised explosive devices and unexploded ordnance

NASA Astrophysics Data System (ADS)

Trammell, Hoke S., III; Perry, Alexander R.; Kumar, Sankaran; Czipott, Peter V.; Whitecotton, Brian R.; McManus, Tobin J.; Walsh, David O.

2005-05-01

Magnetic sensors configured as a tensor magnetic gradiometer not only detect magnetic targets, but also determine their location and their magnetic moment. Magnetic moment information can be used to characterize and classify objects. Unexploded ordnance (UXO) and thus many types of improvised explosive device (IED) contain steel, and thus can be detected magnetically. Suitable unmanned aerial vehicle (UAV) platforms, both gliders and powered craft, can enable coverage of a search area much more rapidly than surveys using, for instance, total-field magnetometers. We present data from gradiometer passes over different shells using a gradiometer mounted on a moving cart. We also provide detection range and speed estimates for aerial detection by a UAV.

CONFERENCE SUMMARY: Summary and comment on superconducting analogue electronics research, including materials and fabrication, as presented at ISEC 07

NASA Astrophysics Data System (ADS)

Foley, C. P.

2007-11-01

The main theme at ISEC 2007 for superconducting materials, fabrication and analogue electronics was the description of incremental developments, including a few new directions that indicate breakthroughs in this area of research. The work on applications focused on their cost-benefit analysis (in order to improve their appeal), the development of simpler systems, making more of the data collected, improving packaging and being responsive to the power handling requirements for commercial systems. All papers presenting this level of research highlighted the importance of obtaining all the necessary details in order to investigate analogue devices and the effectiveness and commercial viability of their systems. This stage of development is important if we are to achieve the transition of superconducting electronics from the laboratory to commercial use. There were some exciting disruptive breakthroughs reported. These were in the areas of nano-SQUIDs, rotating gradiometers, superconducting scanning tunnelling microscopy (Hayashi et al) and the potential of superconducting photonics using optical interfaces with superconducting vortex flow transistors, for example. The materials research in low (LTS), high (HTS) and medium (MTS) critical temperature superconductors was reported. In LTS, nitrides emerged as important materials for use as new tunnel barriers, either insulating or semiconducting. Papers on BaN, NbN, TaN, GaN and Nb-Si superconducting materials were also presented. The MTS material of MgB2 is still under development (Zhao et al). There were also new research groups from South Africa and Turkey attending the conference. The fabrication research presented covered the areas of critical current Ic spread, which is still an issue in reducing the reproducibility of Josephson junctions, a 150 mm process for Nb/Al-AlOx/Nb and methods to improve barrier layers using both new materials and smooth surfaces at thin film interfaces (Du et al). New methods to make sub-micron Josephson junctions using laser etching (Büttner et al) and the development of passivation layers using amorphous YBCO and SiO2 (Seidel et al) were also presented. Characterization methods using Raman and photo-emission spectroscopy (Kikunaga et al) emerged as fresh approaches. Josephson junction (JJ) research covered the areas of critical current fluctuations where results on Tl-based junctions suggested a 40 times lower δI/Ic, and LTS junctions for voltage standards using a Nb-Si barrier for improved SNS junctions (Kieler et al). Development of MTS junctions based on MgB2 are yet to be realized with the interface barrier appearing to be the limiting factor. HTS Josephson junctions were reviewed by asking the question: `Are all HTS JJs the same?' with a clear `no' as the answer. Research on intrinsic stacked junctions, sub-micron junctions, the manipulation of electronic band structure to increase energy gap and mid-gap states was also presented. Developments in packaging and cooling were not as dominant at this conference as in previous years. However, there was research reported on the importance of non-magnetic structures in packaging, the design of magnetic shielding improvement by using finite element analysis to optimize design (Tanaka et al) and the use of cryocoolers (Vernik et al). SQUID research reported some breakthrough developments with new ideas presented on nano-SQUIDs with the possible detection of a ferritin spin-flip, a successful airborne trial using a rotating gradiometer and the development of a new 4 cm long baseline planar gradiometer, achieving a sensitivity of 35 fT cm-1 Hz-½. Applications in non-destructive evaluation (NDE) covered the use of SQUIDs in the detection of stainless steel foreign objects in food, defects in wire and circuit boards and surface imaging with most developments focusing on potential customer requirements. Biomagnetic applications have continued to be embraced in the use of SQUIDs in MRI (Zotev et al), NMR, MEG (including one paper that did not use SQUIDs), immunoassays (close to single cell detection—30 cells to date) and in spinal cord injury detection using quadrapoles. Instrumentation using various devices for thermometers (fast response), micro-susceptometers, current comparators and spin-flip measurements were reported. There were few papers on the use of SQUIDs for geophysical prospecting. This area of application is now commercially mature with research in the field being presented at mineral exploration conferences. However, one paper reported the development of an HTS transient electromagnetic (TEM) system with similar sensitivities to those demonstrated by LTS systems due to improved electronics. The application of nuclear quadrupole resonance for explosives using gate arrays for noise reduction was also reported. There were some novel devices presented with an excellent overview on SQUIFs which were first suggested by Richard Feynman in his well-known university lecture series in physics. This work continues with the aim of achieving the measurement of the absolute value (or true field) of magnetic fields with the question being asked: `Can you really create a zero magnetic field environment?'. Detector research presented at the conference considered the exciting applications in THz imaging. Superconducting bolometers with anti-reflection coatings and using MgB2 (Portesi et al) were reported suggesting improved performance. The application for the improvedr discrimination of radioactive materials by spectroscopy will be very important in the implementation of the Nuclear Non-proliferation Treaty. Single-photon detectors were reported using Nb nanowires (NbN), ferromagnets in nanolayers and SiN transition edge absorbers. Resonators based on SQUID arrays (He et al) and frequency adjustable Josephson junctions were also reported, along with receivers for radio astronomy. Filters have been found to be improved using MgB2, which showed increased Q factors using a split-ring element design (68000 at 5 GHz). This author also used the summing-up session to talk about the need for cooperation leading up to the setting of international standards for superconducting devices. For instance, in the standardization of connections to coolers to enable black box operation, in order to achieve the long-term vision that one day anyone could source a superconducting component from a standard electronics catalogue! Finally, some general comments on the conference. There were not many students (or females) as attendees, which suggests we need to consider more closely the future generation to take the current research to fruition. Nevertheless there was a clear movement forward with some exciting new developments and some new research groups participating, but some important superconducting electronics research groups did not attend. This calls into question the status of the funding of research into superconducting electronics. However, some clear applications, where superconducting electronics provides the only solution, are clearly achieving maturity in their development and adoption. Our research community needs to make sure these developments are recognized to ensure a healthy future for superconducting electronics research, development and commercialization.

Detection of magnetic nanoparticles with a large scale AC superconducting susceptometer

NASA Astrophysics Data System (ADS)

Hincapie Ladino, E. A.; Zufelato, N.; Bakuzis, A. F.; Oliveira Carneiro, A. A.; Covas, D. T.; Baffa, O.

2017-08-01

Magnetic nanoparticles (MNPs) are being used in several applications in medicine such as hyperthermia, magnetic particle imaging, in vitro and in vivo bioassay, and still there are many other possibilities for use of these particles to come as research progress in this field. One crucial step of its use is the detection of these particles when present in a certain tissue. For in vitro bioassay, the sample can be harvested and placed inside the detector in optimal conditions to favor sensitivity. However, for in vivo human measurements the system must be noninvasive and conform to the anatomic restrictions requiring sensitive detectors and dedicated setups. In this study, we detect nanoparticles with an AC biosusceptometer having an excitation homogeneous magnetic field with 145 μT, provided by a set of rectangular large Rubens coils driven at 10 Hz. The magnetization induced in the sample was detected by a second-order axial gradiometer (20 mm in diameter and 40 mm of baseline) coupled to an RF Superconducting Quantum Interference Device (SQUID) model 330X (BTi). The MNPs used were manganese ferrite-based surface-coated with citric acid ({{M}}{{n}}{{F}}{{{e}}}2{{{O}}}4-{{C}}{{i}}{{t}}{{r}}{{a}}{{t}}{{e}}), dissolved in water at various concentrations. The colloid is stable at physiological conditions. X-ray diffraction confirmed the spinel structure and using Scherrer’s relation revealed a particle size of 17.3 nm. The magnetization curve showed a typical superparamagnetic behavior with a specific saturation magnetization of 51.2 emu g-1. The stock solution of nanoparticles had a concentration of 23.17 mg ml-1, corresponding to 1.7 × 1015 NPs ml-1. Measurements were made in a volume of 30 ml with 20 × 103-100 × 103 dilutions of the stock solution of nanoparticles and performed at distances of 1.1, 1.5 and 2.5 cm from the top of the sample vial to the closest coil of the gradiometer. The limits of detection were 8.1 × 109 NP ml-1, 9.5 × 109 NP ml-1 and 11.0 × 109 NP ml-1 for the distances above. These values suggest that the technique might have interesting applications in the real-time in vivo detection of nanoparticles after systemic injections. The present setup can be improved by using more sensitive SQUID sensors and less noisy cryostats.

Superconducting tensor gravity gradiometer

NASA Technical Reports Server (NTRS)

Paik, H. J.

1981-01-01

The employment of superconductivity and other material properties at cryogenic temperatures to fabricate sensitive, low-drift, gravity gradiometer is described. The device yields a reduction of noise of four orders of magnitude over room temperature gradiometers, and direct summation and subtraction of signals from accelerometers in varying orientations are possible with superconducting circuitry. Additional circuits permit determination of the linear and angular acceleration vectors independent of the measurement of the gravity gradient tensor. A dewar flask capable of maintaining helium in a liquid state for a year's duration is under development by NASA, and a superconducting tensor gravity gradiometer for the NASA Geodynamics Program is intended for a LEO polar trajectory to measure the harmonic expansion coefficients of the earth's gravity field up to order 300.

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.

Adaptive suppression of power line interference in ultra-low field magnetic resonance imaging in an unshielded environment.

PubMed

Huang, Xiaolei; Dong, Hui; Qiu, Yang; Li, Bo; Tao, Quan; Zhang, Yi; Krause, Hans-Joachim; Offenhäusser, Andreas; Xie, Xiaoming

2018-01-01

Power-line harmonic interference and fixed-frequency noise peaks may cause stripe-artifacts in ultra-low field (ULF) magnetic resonance imaging (MRI) in an unshielded environment and in a conductively shielded room. In this paper we describe an adaptive suppression method to eliminate these artifacts in MRI images. This technique utilizes spatial correlation of the interference from different positions, and is realized by subtracting the outputs of the reference channel(s) from those of the signal channel(s) using wavelet analysis and the least squares method. The adaptive suppression method is first implemented to remove the image artifacts in simulation. We then experimentally demonstrate the feasibility of this technique by adding three orthogonal superconducting quantum interference device (SQUID) magnetometers as reference channels to compensate the output of one 2nd-order gradiometer. The experimental results show great improvement in the imaging quality in both 1D and 2D MRI images at two common imaging frequencies, 1.3 kHz and 4.8 kHz. At both frequencies, the effective compensation bandwidth is as high as 2 kHz. Furthermore, we examine the longitudinal relaxation times of the same sample before and after compensation, and show that the MRI properties of the sample did not change after applying adaptive suppression. This technique can effectively increase the imaging bandwidth and be applied to ULF MRI detected by either SQUIDs or Faraday coil in both an unshielded environment and a conductively shielded room. Copyright © 2017 Elsevier Inc. All rights reserved.

The DC-SQUID-based Magnetocardiographic Systems for Clinical Use

NASA Astrophysics Data System (ADS)

Maslennikov, Yu. V.; Primin, M. A.; Slobodchikov, V. Yu.; Khanin, V. V.; Nedayvoda, I. V.; Krymov, V. A.; Okunev, A. V.; Moiseenko, E. A.; Beljaev, A. V.; Rybkin, V. S.; Tolcheev, A. V.; Gapelyuk, A. V.

The new line of dc-SQUID-based magnetocardiographic (MCG) systems (named as the "MAG-SCAN"-family) is designed, fabricated and tested. These systems are intended for routine MCG investigations of patients at conditions of real clinical electrophysiological labs. The "MAG-SCAN"-family includes the line of MCG devices compatible in terms of hardware and software with number of measuring channels from 1 to 36. Experimental prototypes of 7- and 9-channel MCG-systems (the models "MAG-SCAN-07" and "MAG-SCAN-09" fabricated at CRYOTON Co. Ltd.) were installed in a few hospitals of Moscow city and operated in an unshielded environment of usual clinical labs. Well balanced second-order gradiometers have been used for MCG data recording. They demonstrated an intrinsic noise level better than 5 fT/√Hz. The total noise level of about 20-40 fT/√Hz was measured at urban conditions of Moscow city. The package of special software (named as the "SOFTMAG") was developed as two autonomous subsystems that allow the preprocessing of the heart magnetic signals and the spatio-temporal analysis of the field characteristics and the field sources. The software employs the algorithms for the analysis and estimation of the spatio-temporal characteristics of the heart magnetic field and the correspondent electrical currents distributions. More than 2000 investigations of different volunteers including healthy persons, patients with high blood-pressure, ischemic disease (IHD), chronic obstructive pulmonary disease (COPD) and bronchial asthma (BA) were carried out and sets of MCG-parameters specific for each group were found.

Development of a Transportable Gravity Gradiometer Based on Atom Interferometry

NASA Astrophysics Data System (ADS)

Yu, N.; Kohel, J. M.; Aveline, D. C.; Kellogg, J. R.; Thompson, R. J.; Maleki, L.

2007-12-01

JPL is developing a transportable gravity gradiometer based on light-pulse atom interferometers for NASA's Earth Science Technology Office's Instrument Incubator Program. The inertial sensors in this instrument employ a quantum interference measurement technique, analogous to the precise phase measurements in atomic clocks, which offers increased sensitivity and improved long-term stability over traditional mechanical devices. We report on the implementation of this technique in JPL's gravity gradiometer, and on the current performance of the mobile instrument. We also discuss the prospects for satellite-based gravity field mapping, including high-resolution monitoring of time-varying fields from a single satellite platform and multi-component measurements of the gravitational gradient tensor, using atom interferometer-based instruments.

Principle and experimental investigation of current-driven negative-inductance superconducting quantum interference device

NASA Astrophysics Data System (ADS)

Li, Hao; Liu, Jianshe; Zhang, Yingshan; Cai, Han; Li, Gang; Liu, Qichun; Han, Siyuan; Chen, Wei

2017-03-01

A negative-inductance superconducting quantum interference device (nSQUID) is an adiabatic superconducting logic device with high energy efficiency, and therefore a promising building block for large-scale low-power superconducting computing. However, the principle of the nSQUID is not that straightforward and an nSQUID driven by voltage is vulnerable to common mode noise. We investigate a single nSQUID driven by current instead of voltage, and clarify the principle of the adiabatic transition of the current-driven nSQUID between different states. The basic logic operations of the current-driven nSQUID with proper parameters are simulated by WRspice. The corresponding circuit is fabricated with a 100 A cm-2 Nb-based lift-off process, and the experimental results at low temperature confirm the basic logic operations as a gated buffer.

Quantum information transfer and entanglement with SQUID qubits in cavity QED: a dark-state scheme with tolerance for nonuniform device parameter.

PubMed

Yang, Chui-Ping; Chu, Shih-I; Han, Siyuan

2004-03-19

We investigate the experimental feasibility of realizing quantum information transfer (QIT) and entanglement with SQUID qubits in a microwave cavity via dark states. Realistic system parameters are presented. Our results show that QIT and entanglement with two-SQUID qubits can be achieved with a high fidelity. The present scheme is tolerant to device parameter nonuniformity. We also show that the strong coupling limit can be achieved with SQUID qubits in a microwave cavity. Thus, cavity-SQUID systems provide a new way for production of nonclassical microwave source and quantum communication.

Scanning SQUID sampler with 40-ps time resolution

NASA Astrophysics Data System (ADS)

Cui, Zheng; Kirtley, John R.; Wang, Yihua; Kratz, Philip A.; Rosenberg, Aaron J.; Watson, Christopher A.; Gibson, Gerald W.; Ketchen, Mark B.; Moler, Kathryn. A.

2017-08-01

Scanning Superconducting QUantum Interference Device (SQUID) microscopy provides valuable information about magnetic properties of materials and devices. The magnetic flux response of the SQUID is often linearized with a flux-locked feedback loop, which limits the response time to microseconds or longer. In this work, we present the design, fabrication, and characterization of a novel scanning SQUID sampler with a 40-ps time resolution and linearized response to periodically triggered signals. Other design features include a micron-scale pickup loop for the detection of local magnetic flux, a field coil to apply a local magnetic field to the sample, and a modulation coil to operate the SQUID sampler in a flux-locked loop to linearize the flux response. The entire sampler device is fabricated on a 2 mm × 2 mm chip and can be scanned over macroscopic planar samples. The flux noise at 4.2 K with 100 kHz repetition rate and 1 s of averaging is of order 1 mΦ0. This SQUID sampler will be useful for imaging dynamics in magnetic and superconducting materials and devices.

Scanning SQUID sampler with 40-ps time resolution.

PubMed

Cui, Zheng; Kirtley, John R; Wang, Yihua; Kratz, Philip A; Rosenberg, Aaron J; Watson, Christopher A; Gibson, Gerald W; Ketchen, Mark B; Moler, Kathryn A

2017-08-01

Scanning Superconducting QUantum Interference Device (SQUID) microscopy provides valuable information about magnetic properties of materials and devices. The magnetic flux response of the SQUID is often linearized with a flux-locked feedback loop, which limits the response time to microseconds or longer. In this work, we present the design, fabrication, and characterization of a novel scanning SQUID sampler with a 40-ps time resolution and linearized response to periodically triggered signals. Other design features include a micron-scale pickup loop for the detection of local magnetic flux, a field coil to apply a local magnetic field to the sample, and a modulation coil to operate the SQUID sampler in a flux-locked loop to linearize the flux response. The entire sampler device is fabricated on a 2 mm × 2 mm chip and can be scanned over macroscopic planar samples. The flux noise at 4.2 K with 100 kHz repetition rate and 1 s of averaging is of order 1 mΦ 0 . This SQUID sampler will be useful for imaging dynamics in magnetic and superconducting materials and devices.

NanoSQUIDs: Basics & recent advances

NASA Astrophysics Data System (ADS)

José Martínez-Pérez, Maria; Koelle, Dieter

2017-08-01

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

Inductance analysis of superconducting quantum interference devices with 3D nano-bridge junctions

NASA Astrophysics Data System (ADS)

Wang, Hao; Yang, Ruoting; Li, Guanqun; Wu, Long; Liu, Xiaoyu; Chen, Lei; Ren, Jie; Wang, Zhen

2018-05-01

Superconducting quantum interference devices (SQUIDs) with 3D nano-bridge junctions can be miniaturized into nano-SQUIDs that are able to sense a few spins in a large magnetic field. Among all device parameters, the inductance is key to the performance of SQUIDs with 3D nano-bridge junctions. Here, we measured the critical-current magnetic flux modulation curves of 12 devices with three design types using a current strip-line directly coupled to the SQUID loop. A best flux modulation depth of 71% was achieved for our 3D Nb SQUID. From the modulation curves, we extracted the inductance values of the current stripe-line in each design and compared them with the corresponding simulation results of InductEX. In this way, London penetration depths of 110 and 420 nm were determined for our Nb (niobium) and NbN (niobium nitride) films, respectively. Furthermore, we showed that inductances of 11 and 119 pH for Nb and NbN 3D nano-bridge junctions, respectively, dominated the total inductance of our SQUID loops which are 23 pH for Nb and 255 pH for NbN. A screening parameter being equal to one suggests optimal critical currents of 89.6 and 8.1 μA for Nb and NbN SQUIDs, respectively. Additionally, intrinsic flux noise of 110 ± 40 nΦ0/(Hz)1/2 is calculated for the Nb SQUIDs with 3D nano-bridge junctions by Langevin simulation.

A YBCO RF-squid variable temperature susceptometer and its applications

NASA Technical Reports Server (NTRS)

Zhou, Luwei; Qiu, Jinwu; Zhang, Xianfeng; Tang, Zhimin; Cai, Yimin; Qian, Yongjia

1991-01-01

The Superconducting QUantum Interference Device (SQUID) susceptibility using a high-temperature radio-frequency (rf) SQUID and a normal metal pick-up coil is employed in testing weak magnetization of the sample. The magnetic moment resolution of the device is 1 x 10(exp -6) emu, and that of the susceptibility is 5 x 10(exp -6) emu/cu cm.

SQUID magnetometers for low-frequency applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ryhaenen, T.; Seppae, H.; Ilmoniemi, R.

1989-09-01

The authors present a novel formulation for SQUID operation, which enables them to evaluate and compare the sensitivity and applicability of different devices. SQUID magnetometers for low-frequency applications are analyzed, taking into account the coupling circuits and electronics. They discuss nonhysteretic and hysteretic single-junction rf SQUIDs, but the main emphasis is on the dynamics, sensitivity, and coupling considerations of dc-SQUID magnetometers. A short review of current ideas on thin-film, dc-SQUID design presents the problems in coupling and the basic limits of sensitivity. The fabrication technology of tunnel-junction devices is discussed with emphasis on how it limits critical current densities, specificmore » capacitances of junctions, minimum linewidths, conductor separations, etc. Properties of high-temperature superconductors are evaluated on the basis of recently published results on increased flux creep, low density of current carriers, and problems in fabricating reliable junctions. The optimization of electronics for different types of SQUIDs is presented. Finally, the most important low-frequency applications of SQUIDs in biomagnetism, metrology, geomagnetism, and some physics experiments demonstrate the various possibilities that state-of-the-art SQUIDs can provide.« less

Magnetoencephalography with a Cs-based high-sensitivity compact atomic magnetometer

NASA Astrophysics Data System (ADS)

Sheng, Jingwei; Wan, Shuangai; Sun, Yifan; Dou, Rongshe; Guo, Yuhao; Wei, Kequan; He, Kaiyan; Qin, Jie; Gao, Jia-Hong

2017-09-01

In recent years, substantial progress has been made in developing a new generation of magnetoencephalography (MEG) with a spin-exchange relaxation free (SERF)-based atomic magnetometer (AM). An AM employs alkali atoms to detect weak magnetic fields. A compact AM array with high sensitivity is crucial to the design; however, most proposed compact AMs are potassium (K)- or rubidium (Rb)-based with single beam configurations. In the present study, a pump-probe two beam configuration with a Cesium (Cs)-based AM (Cs-AM) is introduced to detect human neuronal magnetic fields. The length of the vapor cell is 4 mm, which can fully satisfy the need of designing a compact sensor array. Compared with state-of-the-art compact AMs, our new Cs-AM has two advantages. First, it can be operated in a SERF regime, requiring much lower heating temperature, which benefits the sensor with a closer distance to scalp due to ease of thermal insulation and less electric heating noise interference. Second, the two-beam configuration in the design can achieve higher sensitivity. It is free of magnetic modulation, which is necessary in one-beam AMs; however, such modulation may cause other interference in multi-channel circumstances. In the frequency band between 10 Hz and 30 Hz, the noise level of the proposed Cs-AM is approximately 10 f T/Hz1/2, which is comparable with state-of-the-art K- or Rb-based compact AMs. The performance of the Cs-AM was verified by measuring human auditory evoked fields (AEFs) in reference to commercial superconducting quantum interference device (SQUID) channels. By using a Cs-AM, we observed a clear peak in AEFs around 100 ms (M100) with a much larger amplitude compared with that of a SQUID, and the temporal profiles of the two devices were in good agreement. The results indicate the possibility of using the compact Cs-AM for MEG recordings, and the current Cs-AM has the potential to be designed for multi-sensor arrays and gradiometers for future neuroscience studies.

Non-invasive detection of language-related prefrontal high gamma band activity with beamforming MEG.

PubMed

Hashimoto, Hiroaki; Hasegawa, Yuka; Araki, Toshihiko; Sugata, Hisato; Yanagisawa, Takufumi; Yorifuji, Shiro; Hirata, Masayuki

2017-10-27

High gamma band (>50 Hz) activity is a key oscillatory phenomenon of brain activation. However, there has not been a non-invasive method established to detect language-related high gamma band activity. We used a 160-channel whole-head magnetoencephalography (MEG) system equipped with superconducting quantum interference device (SQUID) gradiometers to non-invasively investigate neuromagnetic activities during silent reading and verb generation tasks in 15 healthy participants. Individual data were divided into alpha (8-13 Hz), beta (13-25 Hz), low gamma (25-50 Hz), and high gamma (50-100 Hz) bands and analysed with the beamformer method. The time window was consecutively moved. Group analysis was performed to delineate common areas of brain activation. In the verb generation task, transient power increases in the high gamma band appeared in the left middle frontal gyrus (MFG) at the 550-750 ms post-stimulus window. We set a virtual sensor on the left MFG for time-frequency analysis, and high gamma event-related synchronization (ERS) induced by a verb generation task was demonstrated at 650 ms. In contrast, ERS in the high gamma band was not detected in the silent reading task. Thus, our study successfully non-invasively measured language-related prefrontal high gamma band activity.

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.

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.

Charge dissipative dielectric for cryogenic devices

NASA Technical Reports Server (NTRS)

Cantor, Robin Harold (Inventor); Hall, John Addison (Inventor)

2007-01-01

A Superconducting Quantum Interference Device (SQUID) is disclosed comprising a pair of resistively shunted Josephson junctions connected in parallel within a superconducting loop and biased by an external direct current (dc) source. The SQUID comprises a semiconductor substrate and at least one superconducting layer. The metal layer(s) are separated by or covered with a semiconductor material layer having the properties of a conductor at room temperature and the properties of an insulator at operating temperatures (generally less than 100 Kelvins). The properties of the semiconductor material layer greatly reduces the risk of electrostatic discharge that can damage the device during normal handling of the device at room temperature, while still providing the insulating properties desired to allow normal functioning of the device at its operating temperature. A method of manufacturing the SQUID device is also disclosed.

Transport characteristics of μ-SQUIDs for probing magnetism

NASA Astrophysics Data System (ADS)

Biswas, Sourav; Paul, Sagar; Parashari, Harsh; Winkelmann, Clemens B.; Courtois, Hervé; Gupta, Anjan K.

2018-04-01

We study the transport properties of niobium (Nb) based micron sized superconducting quantum interference devices (μ-SQUID), which are designed to eliminate thermal hysteresis down to 1.3 K. Current-voltage characteristics are non-hysterestic at the lowest temperature. Large voltage oscillations with magnetic field are observed for a wide range of bias currents with good flux sensitivity and reduced flux noise. However, devices with fins and devices on sapphire substrate show hysteresis for wide range of bath temperature. We have also been able to see the sign of magnetic response from a single micron size ferromagnetic permalloy ellipse using the μ-SQUID.

Fabrication of Superconducting Quantum Interference Device Magnetometers on a Glass Epoxy Polyimide Resin Substrate with Copper Terminals

NASA Astrophysics Data System (ADS)

Kawai, Jun; Kawabata, Miki; Oyama, Daisuke; Uehara, Gen

We have developed fabrication technique of superconducting quantum interference device (SQUID) magnetometers based on Nb/AlAlOx/Nb junctions directly on a glass epoxy polyimide resin substrate, which has copper terminals embedded in advance. The advantage of this method is that no additional substrate and wirebonds are needed for assembly. Compared to conventional SQUID magnetometers, which are assembled with a SQUID chip fabricated on a Si substrate and wirebonding technique, low risk of disconnection can be expected. A directly-coupled multi-loop SQUID magnetometer fabricated with this method has as good noise performance as a SQUID magnetometer with the same design fabricated on a Si wafer. The magnetometer sustained its performance through thermal cycle test 13 times so far.

A microfabricated optically-pumped magnetic gradiometer

NASA Astrophysics Data System (ADS)

Sheng, D.; Perry, A. R.; Krzyzewski, S. P.; Geller, S.; Kitching, J.; Knappe, S.

2017-01-01

We report on the development of a microfabricated atomic magnetic gradiometer based on optical spectroscopy of alkali atoms in the vapor phase. The gradiometer, which operates in the spin-exchange relaxation free regime, has a length of 60 mm and cross sectional diameter of 12 mm, and consists of two chip-scale atomic magnetometers which are interrogated by a common laser light. The sensor can measure differences in magnetic fields, over a 20 mm baseline, of 10 fT/ Hz1 /2 at frequencies above 20 Hz. The maximum rejection of magnetic field noise is 1000 at 10 Hz. By use of a set of compensation coils wrapped around the sensor, we also measure the sensor sensitivity at several external bias field strengths up to 150 mG. This device is useful for applications that require both sensitive gradient field information and high common-mode noise cancellation.

Measurement of the dynamic input impedance of a dc superconducting quantum interference device at audio frequencies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Falferi, P.; Mezzena, R.; Vitale, S.

1997-08-01

The coupling effects of a commercial dc superconducting quantum interference device (SQUID) to an electrical LC resonator which operates at audio frequencies ({approx}1kHz) with quality factors Q{approx}10{sup 6} are presented. The variations of the resonance frequency of the resonator as functions of the flux applied to the SQUID are due to the SQUID dynamic inductance in good agreement with the predictions of a model. The variations of the quality factor point to a feedback mechanism between the output of the SQUID and the input circuit. {copyright} {ital 1997 American Institute of Physics.}

Radiofrequency amplifier based on a dc superconducting quantum interference device

DOEpatents

Hilbert, C.; Martinis, J.M.; Clarke, J.

1984-04-27

A low noise radiofrequency amplifer, using a dc SQUID (superconducting quantum interference device) as the input amplifying element. The dc SQUID and an input coil are maintained at superconductivity temperatures in a superconducting shield, with the input coil inductively coupled to the superconducting ring of the dc SQUID. A radiofrequency signal from outside the shield is applied to the input coil, and an amplified radiofrequency signal is developed across the dc SQUID ring and transmitted to exteriorly of the shield. A power gain of 19.5 +- 0.5 dB has been achieved with a noise temperature of 1.0 +- 0.4 K at a frequency of 100 MHz.

BabyMEG: A whole-head pediatric magnetoencephalography system for human brain development research

NASA Astrophysics Data System (ADS)

Okada, Yoshio; Hämäläinen, Matti; Pratt, Kevin; Mascarenas, Anthony; Miller, Paul; Han, Menglai; Robles, Jose; Cavallini, Anders; Power, Bill; Sieng, Kosal; Sun, Limin; Lew, Seok; Doshi, Chiran; Ahtam, Banu; Dinh, Christoph; Esch, Lorenz; Grant, Ellen; Nummenmaa, Aapo; Paulson, Douglas

2016-09-01

We developed a 375-channel, whole-head magnetoencephalography (MEG) system ("BabyMEG") for studying the electrophysiological development of human brain during the first years of life. The helmet accommodates heads up to 95% of 36-month old boys in the USA. The unique two-layer sensor array consists of: (1) 270 magnetometers (10 mm diameter, ˜15 mm coil-to-coil spacing) in the inner layer, (2) thirty-five three-axis magnetometers (20 mm × 20 mm) in the outer layer 4 cm away from the inner layer. Additionally, there are three three-axis reference magnetometers. With the help of a remotely operated position adjustment mechanism, the sensor array can be positioned to provide a uniform short spacing (mean 8.5 mm) between the sensor array and room temperature surface of the dewar. The sensors are connected to superconducting quantum interference devices (SQUIDs) operating at 4.2 K with median sensitivity levels of 7.5 fT/√Hz for the inner and 4 fT/√Hz for the outer layer sensors. SQUID outputs are digitized by a 24-bit acquisition system. A closed-cycle helium recycler provides maintenance-free continuous operation, eliminating the need for helium, with no interruption needed during MEG measurements. BabyMEG with the recycler has been fully operational from March, 2015. Ongoing spontaneous brain activity can be monitored in real time without interference from external magnetic noise sources including the recycler, using a combination of a lightly shielded two-layer magnetically shielded room, an external active shielding, a signal-space projection method, and a synthetic gradiometer approach. Evoked responses in the cortex can be clearly detected without averaging. These new design features and capabilities represent several advances in MEG, increasing the utility of this technique in basic neuroscience as well as in clinical research and patient studies.

BabyMEG: A whole-head pediatric magnetoencephalography system for human brain development research.

PubMed

Okada, Yoshio; Hämäläinen, Matti; Pratt, Kevin; Mascarenas, Anthony; Miller, Paul; Han, Menglai; Robles, Jose; Cavallini, Anders; Power, Bill; Sieng, Kosal; Sun, Limin; Lew, Seok; Doshi, Chiran; Ahtam, Banu; Dinh, Christoph; Esch, Lorenz; Grant, Ellen; Nummenmaa, Aapo; Paulson, Douglas

2016-09-01

We developed a 375-channel, whole-head magnetoencephalography (MEG) system ("BabyMEG") for studying the electrophysiological development of human brain during the first years of life. The helmet accommodates heads up to 95% of 36-month old boys in the USA. The unique two-layer sensor array consists of: (1) 270 magnetometers (10 mm diameter, ∼15 mm coil-to-coil spacing) in the inner layer, (2) thirty-five three-axis magnetometers (20 mm × 20 mm) in the outer layer 4 cm away from the inner layer. Additionally, there are three three-axis reference magnetometers. With the help of a remotely operated position adjustment mechanism, the sensor array can be positioned to provide a uniform short spacing (mean 8.5 mm) between the sensor array and room temperature surface of the dewar. The sensors are connected to superconducting quantum interference devices (SQUIDs) operating at 4.2 K with median sensitivity levels of 7.5 fT/√Hz for the inner and 4 fT/√Hz for the outer layer sensors. SQUID outputs are digitized by a 24-bit acquisition system. A closed-cycle helium recycler provides maintenance-free continuous operation, eliminating the need for helium, with no interruption needed during MEG measurements. BabyMEG with the recycler has been fully operational from March, 2015. Ongoing spontaneous brain activity can be monitored in real time without interference from external magnetic noise sources including the recycler, using a combination of a lightly shielded two-layer magnetically shielded room, an external active shielding, a signal-space projection method, and a synthetic gradiometer approach. Evoked responses in the cortex can be clearly detected without averaging. These new design features and capabilities represent several advances in MEG, increasing the utility of this technique in basic neuroscience as well as in clinical research and patient studies.

Low noise niobium dc SQUID with a planar input coil

NASA Astrophysics Data System (ADS)

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

1983-02-01

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

Mathematical modeling of fluxgate magnetic gradiometers

NASA Astrophysics Data System (ADS)

Milovzorov, D. G.; Yasoveev, V. Kh.

2017-07-01

Issues of designing fluxgate magnetic gradiometers are considered. The areas of application of fluxgate magnetic gradiometers are determined. The structure and layout of a two-component fluxgate magnetic gradiometer are presented. It is assumed that the fluxgates are strictly coaxial in the gradiometer body. Elements of the classical approach to the mathematical modeling of the spatial arrangement of solids are considered. The bases of the gradiometer body and their transformations during spatial displacement of the gradiometer are given. The problems of mathematical modeling of gradiometers are formulated, basic mathematical models of a two-component fluxgate gradiometer are developed, and the mathematical models are analyzed. A computer experiment was performed. Difference signals from the gradiometer fluxgates for the vertical and horizontal position of the gradiometer body are shown graphically as functions of the magnitude and direction of the geomagnetic field strength vector.

Flux Noise due to Spins in SQUIDs

NASA Astrophysics Data System (ADS)

LaForest, Stephanie

Superconducting Quantum Interference Devices (SQUIDs) are currently being used as flux qubits and read-out detectors in a variety of solid-state quantum computer architectures. The main limitation of SQUID qubits is that they have a coherence time of the order of 10 micros, due to the presence of intrinsic flux noise that is not yet fully understood. The origin of flux noise is currently believed to be related to spin impurities present in the materials and interfaces that form the device. Here we present a novel numerical method that enables calculations of the flux produced by spin impurities even when they are located quite close to the SQUID wire. We show that the SQUID will be particularly sensitive to spins located at its wire edges, generating flux shifts of up to 4 nano flux quanta, much higher than previous calculations based on the software package FastHenry. This shows that spin impurities in a particular region along the wire's surface play a much more important role in producing flux noise than other spin impurities located elsewhere in the device.

NASA Tech Briefs, April 2009

NASA Technical Reports Server (NTRS)

2009-01-01

Topics covered include: Direct-Solve Image-Based Wavefront Sensing; Use of UV Sources for Detection and Identification of Explosives; Using Fluorescent Viruses for Detecting Bacteria in Water; Gradiometer Using Middle Loops as Sensing Elements in a Low-Field SQUID MRI System; Volcano Monitor: Autonomous Triggering of In-Situ Sensors; Wireless Fluid-Level Sensors for Harsh Environments; Interference-Detection Module in a Digital Radar Receiver; Modal Vibration Analysis of Large Castings; Structural/Radiation-Shielding Epoxies; Integrated Multilayer Insulation; Apparatus for Screening Multiple Oxygen-Reduction Catalysts; Determining Aliasing in Isolated Signal Conditioning Modules; Composite Bipolar Plate for Unitized Fuel Cell/Electrolyzer Systems; Spectrum Analyzers Incorporating Tunable WGM Resonators; Quantum-Well Thermophotovoltaic Cells; Bounded-Angle Iterative Decoding of LDPC Codes; Conversion from Tree to Graph Representation of Requirements; Parallel Hybrid Vehicle Optimal Storage System; and Anaerobic Digestion in a Flooded Densified Leachbed.

Fabrication of sapphire-based high performance step-edge HTS Josephson junctions and SQUIDs and their application to scanning SQUID microscopy

NASA Astrophysics Data System (ADS)

Ming, Bin

Josephson junctions are at the heart of any superconductor device applications. A SQUID (Superconducting Quantum Interference Device), which consists of two Josephson junctions, is by far the most important example. Unfortunately, in the case of high-Tc superconductors (HTS), the quest for a robust, flexible, and high performance junction technology is yet far from the end. Currently, the only proven method to make HTS junctions is the SrTiO3(STO)-based bicrystal technology. In this thesis we concentrate on the fabrication of YBCO step-edge junctions and SQUIDs on sapphire. The step-edge method provides complete control of device locations and facilitates sophisticated, high-density layout. We select CeO2 as the buffer layer, as the key step to make device quality YBCO thin films on sapphire. With an "overhang" shadow mask produced by a novel photolithography technique, a steep step edge was fabricated on the CeO2 buffer layer by Ar+ ion milling with optimized parameters for minimum ion beam divergence. The step angle was determined to be in excess of 80° by atomic force microscopy (AFM). Josephson junctions patterned from those step edges exhibited resistively shunted junction (RSJ) like current-voltage characteristics. IcR n values in the 200--500 mV range were measured at 77K. Shapiro steps were observed under microwave irradiation, reflecting the true Josephson nature of those junctions. The magnetic field dependence of the junction Ic indicates a uniform current distribution. These results suggest that all fabrication processes are well controlled and the step edge is relatively straight and free of microstructural defects. The SQUIDs made from the same process exhibit large voltage modulation in a varying magnetic field. At 77K, our sapphire-based step-edge SQUID has a low white noise level at 3muphi0/ Hz , as compared to typically >10muphi0/ Hz from the best bicrystal STO SQUIDS. Our effort at device fabrication is chiefly motivated by the scanning SQUID microscopy (SSM) application. A scanning SQUID microscope is a non-contact, non-destructive imaging tool that can resolve weak currents beneath the sample surface by detecting their magnetic fields. Our low-noise sapphire-based step-edge SQUIDs should be particularly suitable for such an application. An earlier effort to make SNS trench junctions using focused ion beam (FIB) is reviewed in a separate chapter. (Abstract shortened by UMI.)

Radiofrequency amplifier based on a dc superconducting quantum interference device

DOEpatents

Hilbert, Claude; Martinis, John M.; Clarke, John

1986-01-01

A low noise radiofrequency amplifier (10), using a dc SQUID (superconducting quantum interference device) as the input amplifying element. The dc SQUID (11) and an input coil (12) are maintained at superconductivity temperatures in a superconducting shield (13), with the input coil (12) inductively coupled to the superconducting ring (17) of the dc SQUID (11). A radiofrequency signal from outside the shield (13) is applied to the input coil (12), and an amplified radiofrequency signal is developed across the dc SQUID ring (17) and transmitted to exteriorly of the shield (13). A power gain of 19.5.+-.0.5 dB has been achieved with a noise temperature of 1.0.+-.0.4 K. at a frequency of 100 MHz.

Cosmological flux noise and measured noise power spectra in SQUIDs

PubMed Central

Beck, Christian

2016-01-01

The understanding of the origin of 1/f magnetic flux noise commonly observed in superconducting devices such as SQUIDs and qubits is still a major unsolved puzzle. Here we discuss the possibility that a significant part of the observed low-frequency flux noise measured in these devices is ultimately seeded by cosmological fluctuations. We consider a theory where a primordial flux noise field left over in unchanged form from an early inflationary or quantum gravity epoch of the universe intrinsically influences the phase difference in SQUIDs and qubits. The perturbation seeds generated by this field can explain in a quantitatively correct way the form and amplitude of measured low-frequency flux noise spectra in SQUID devices if one takes as a source of fluctuations the primordial power spectrum of curvature fluctuations as measured by the Planck collaboration. Our theoretical predictions are in excellent agreement with recent low-frequency flux noise measurements of various experimental groups. Magnetic flux noise, so far mainly considered as a nuisance for electronic devices, may thus contain valuable information about fluctuation spectra in the very early universe. PMID:27320418

Cosmological flux noise and measured noise power spectra in SQUIDs.

PubMed

Beck, Christian

2016-06-20

The understanding of the origin of 1/f magnetic flux noise commonly observed in superconducting devices such as SQUIDs and qubits is still a major unsolved puzzle. Here we discuss the possibility that a significant part of the observed low-frequency flux noise measured in these devices is ultimately seeded by cosmological fluctuations. We consider a theory where a primordial flux noise field left over in unchanged form from an early inflationary or quantum gravity epoch of the universe intrinsically influences the phase difference in SQUIDs and qubits. The perturbation seeds generated by this field can explain in a quantitatively correct way the form and amplitude of measured low-frequency flux noise spectra in SQUID devices if one takes as a source of fluctuations the primordial power spectrum of curvature fluctuations as measured by the Planck collaboration. Our theoretical predictions are in excellent agreement with recent low-frequency flux noise measurements of various experimental groups. Magnetic flux noise, so far mainly considered as a nuisance for electronic devices, may thus contain valuable information about fluctuation spectra in the very early universe.

Analytical approximations to the dynamics of an array of coupled DC SQUIDs

NASA Astrophysics Data System (ADS)

Berggren, Susan; Palacios, Antonio

2014-04-01

Coupled dynamical systems that operate near the onset of a bifurcation can lead, under certain conditions, to strong signal amplification effects. Over the past years we have studied this generic feature on a wide range of systems, including: magnetic and electric fields sensors, gyroscopic devices, and arrays of loops of superconducting quantum interference devices, also known as SQUIDs. In this work, we consider an array of SQUID loops connected in series as a case study to derive asymptotic analytical approximations to the exact solutions through perturbation analysis. Two approaches are considered. First, a straightforward expansion in which the non-linear parameter related to the inductance of the DC SQUID is treated as the small perturbation parameter. Second, a more accurate procedure that considers the SQUID phase dynamics as non-uniform motion on a circle. This second procedure is readily extended to the series array and it could serve as a mathematical framework to find approximate solutions to related complex systems with high-dimensionality. To the best of our knowledge, an approximate analytical solutions to an array of SQUIDs has not been reported yet in the literature.

Computational and Mathematical Modeling of Coupled Superconducting Quantum Interference Devices

NASA Astrophysics Data System (ADS)

Berggren, Susan Anne Elizabeth

This research focuses on conducting an extensive computational investigation and mathematical analysis into the average voltage response of arrays of Superconducting Quantum Interference Devices (SQUIDs). These arrays will serve as the basis for the development of a sensitive, low noise, significantly lower Size, Weight and Power (SWaP) antenna integrated with Low-Noise Amplifier (LNA) using the SQUID technology. The goal for this antenna is to be capable of meeting all requirements for Guided Missile Destroyers (DDG) 1000 class ships for Information Operations/Signals Intelligence (IO/SIGINT) applications in Very High Frequency/Ultra High Frequency (V/UHF) bands. The device will increase the listening capability of receivers by moving technology into a new regime of energy detection allowing wider band, smaller size, more sensitive, stealthier systems. The smaller size and greater sensitivity will allow for ships to be “de-cluttered” of their current large dishes and devices, replacing everything with fewer and smaller SQUID antenna devices. The fewer devices present on the deck of a ship, the more invisible the ship will be to enemy forces. We invent new arrays of SQUIDs, optimized for signal detection with very high dynamic range and excellent spur-free dynamic range, while maintaining extreme small size (and low radar cross section), wide bandwidth, and environmentally noise limited sensitivity, effectively shifting the bottle neck of receiver systems forever away from the antenna itself deeper into the receiver chain. To accomplish these goals we develop and validate mathematical models for different designs of SQUID arrays and use them to invent a new device and systems design. This design is capable of significantly exceeding, per size weight and power, state-of-the-art receiver system measures of performance, such as bandwidth, sensitivity, dynamic range, and spurious-free dynamic range.

Characterization of a low frequency magnetic noise from a two-stage pulse tube cryocooler

NASA Astrophysics Data System (ADS)

Eshraghi, M. J.; Sasada, I.; Kim, J. M.; Lee, Y. H.

2009-07-01

Magnetic noise of a two-stage pulse tube cryocooler (PT) was measured by a fundamental mode orthogonal fluxgate magnetometer and by a LTS Double Relaxation Oscillation SQUID (DROS) first-order planar gradiometer. The magnetometer was installed in a dewar made of aluminum at 12 cm distance from a section containing magnetic regenerative materials of the second pulse tube. The magnetic noise spectrum showed a clear peak at 1.8 Hz, which is the fundamental frequency of the He gas pumping rate. The 1.8 Hz magnetic noise registered a peak, during the cooling down process, when the second cold-stage temperature was around 12 K, which is well correlated with the 1.8 Hz variation of the temperature of the second cold stage. Hence, we attributed the main source of this magnetic noise to the temperature variation of the magnetic moments resulting from magnetic regenerative materials, Er 3Ni and HoCu 2, in the presence of background static magnetic fields. We have also pointed out that the superconducting magnetic shield of lead sheets reduced the low frequency magnetic noise generated from the magnetic regenerative materials. With this arrangement, the magnetic noise amplitude measured with the LTS DROS gradiometer, mounted at 7 cm horizontal distance from the magnetic regenerative materials, in the optimum condition, was lower than 500 pT peak-to-peak, whereas the noise level without lead shielding was higher than the dynamic range of DROS instrumentations which was around ±10nT.

Note: Low temperature superconductor superconducting quantum interference device system with wide pickup coil for detecting small metallic particles

NASA Astrophysics Data System (ADS)

Kandori, Akihiko; Ogata, Kuniomi; Kawabata, Ryuzo; Tanimoto, Sayaka; Seki, Yusuke

2012-07-01

A one-channel low temperature superconductor superconducting quantum interference device system comprising a second-order axial gradiometer with a sensing area of 10 mm × 190 mm was developed. The gradiometer was mounted in a liquid-helium dewar (450-mm diameter; 975-mm length), with a gap of 12 mm between the pickup coil and the dewar-tail surface. The magnetic field sensitivity was measured to be 16 fT/Hz1/2 in the white noise regime above 2 Hz. The system was used to measure stainless steel particles of different sizes passing through the sensing area. A 100-μm diameter SUS304 particle was readily detected passing at different positions underneath the large pickup coil by measuring its 1.3-pT magnetic field. Thus, the system was shown to be applicable to quality control of lamination sheet products such as lithium ion batteries.

Development of a Cryostat to Characterize Nano-scale Superconducting Quantum Interference Devices

NASA Astrophysics Data System (ADS)

Longo, Mathew; Matheny, Matthew; Knudsen, Jasmine

2016-03-01

We have designed and constructed a low-noise vacuum cryostat to be used for the characterization of nano-scale superconducting quantum interference devices (SQUIDs). Such devices are very sensitive to magnetic fields and can measure changes in flux on the order of a single electron magnetic moment. As a part of the design process, we calculated the separation required between the cryogenic preamplifier and superconducting magnet, including a high-permeability magnetic shield, using a finite-element model of the apparatus. The cryostat comprises a vacuum cross at room temperature for filtered DC and shielded RF electrical connections, a thin-wall stainless steel support tube, a taper-sealed cryogenic vacuum can, and internal mechanical support and wiring for the nanoSQUID. The Dewar is modified with a room-temperature flange with a sliding seal for the cryostat. The flange supports the superconducting 3 Tesla magnet and thermometry wiring. Upon completion of the cryostat fabrication and Dewar modifications, operation of the nanoSQUIDs as transported from our collaborator's laboratory in Israel will be confirmed, as the lead forming the SQUID is sensitive to oxidation and the SQUIDs must be shipped in a vacuum container. After operation of the nanoSQUIDs is confirmed, the primary work of characterizing their high-speed properties will begin. This will include looking at the measurement of relaxation oscillations at high bandwidth in comparison to the theoretical predictions of the current model.

Note: Increasing dynamic range of digital-to-analog converter using a superconducting quantum interference device

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nakanishi, Masakazu, E-mail: m.nakanishi@aist.go.jp

Responses of a superconducting quantum interference device (SQUID) are periodically dependent on magnetic flux coupling to its superconducting ring and the period is a flux quantum (Φ{sub o} = h/2e, where h and e, respectively, express Planck's constant and elementary charge). Using this periodicity, we had proposed a digital to analog converter using a SQUID (SQUID DAC) of first generation with linear current output, interval of which corresponded to Φ{sub o}. Modification for increasing dynamic range by interpolating within each interval is reported. Linearity of the interpolation was also based on the quantum periodicity. A SQUID DAC with dynamic rangemore » of about 1.4 × 10{sup 7} was created as a demonstration.« less

Superconducting quantum interference device with frequency-dependent damping: Readout of flux qubits

NASA Astrophysics Data System (ADS)

Robertson, T. L.; Plourde, B. L. T.; Hime, T.; Linzen, S.; Reichardt, P. A.; Wilhelm, F. K.; Clarke, John

2005-07-01

Recent experiments on superconducting flux qubits, consisting of a superconducting loop interrupted by Josephson junctions, have demonstrated quantum coherence between two different quantum states. The state of the qubit is measured with a superconducting quantum interference device (SQUID). Such measurements require the SQUID to have high resolution while exerting minimal backaction on the qubit. By designing shunts across the SQUID junctions appropriately, one can improve the measurement resolution without increasing the backaction significantly. Using a path-integral approach to analyze the Caldeira-Leggett model, we calculate the narrowing of the distribution of the switching events from the zero-voltage state of the SQUID for arbitrary shunt admittances, focusing on shunts consisting of a capacitance Cs and resistance Rs in series. To test this model, we fabricated a dc SQUID in which each junction is shunted with a thin-film interdigitated capacitor in series with a resistor, and measured the switching distribution as a function of temperature and applied magnetic flux. After accounting for the damping due to the SQUID leads, we found good agreement between the measured escape rates and the predictions of our model. We analyze the backaction of a shunted symmetric SQUID on a flux qubit. For the given parameters of our SQUID and realistic parameters for a flux qubit, at the degeneracy point we find a relaxation time of 113μs , which limits the decoherence time to 226μs . Based on our analysis of the escape process, we determine that a SQUID with purely capacitive shunts should have narrow switching distributions and no dissipation.

Technical and commerical challenges in high Tc SQUIDs and their industrial applications

NASA Technical Reports Server (NTRS)

Lu, D. F.

1995-01-01

A SQUID is the most sensitive device for measuring changes in magnetic flux. Since its discovery in the sixties, scientists have made consistent efforts to apply SQUID's to various applications. Instruments that are the most sensitive in their respective categories have been built, such as SQUID DC susceptometer that is now manufactured by Quantum Design, pico-voltmeter which could measure 10(exp -14) volts, and gravitational wave detectors. One of the most successful applications of SQUID's is in magnetoencephalography, a non-invasive technique for investigating neuronal activity in the living human brain. This technique employs a multi-channel SQUID magnetometer that maps the weak magnetic field generated by small current when information is processed in brain, and its performance is marvelous.

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.

Magnetoelectric gradiometer with enhanced vibration rejection efficiency under H-field modulation

NASA Astrophysics Data System (ADS)

Xu, Junran; Zhuang, Xin; Leung, Chung Ming; Staruch, Margo; Finkel, Peter; Li, Jiefang; Viehland, D.

2018-03-01

A magnetoelectric (ME) gradiometer consisting of two Metglas/Pb(Zr,Ti)O3 fiber-based sensors has been developed. The equivalent magnetic noise of both sensors was first determined to be about 60 pT/√Hz while using an H-field modulation technique. The common mode rejection ratio of a gradiometer based on these two sensors was determined to be 74. The gradiometer response curve was then measured, which provided the dependence of the gradiometer output as a function of the source-gradiometer-normalized distance. Investigations in the presence of vibration noise revealed that a ME gradiometer consisting of two ME magnetometers working under H-field modulation was capable of significant vibration rejection. The results were compared to similar studies of ME gradiometers operated in a passive working mode. Our findings demonstrate that this active gradiometer has a good vibration rejection capability in the presence of both magnetic signals and vibration noise/interferences by using two magnetoelectric sensors operated under H-field modulation.

Low-noise magnetoencephalography system cooled by a continuously operating reliquefier

NASA Astrophysics Data System (ADS)

Lee, Y. H.; Kwon, H.; Yu, K. K.; Kim, J. M.; Lee, S. K.; Kim, M.-Y.; Kim, K.

2017-08-01

We fabricated a low-noise magnetoencephalography (MEG) system based on a continuously operating reliquefier for cooling of low-temperature superconducting quantum interference device gradiometers. In order to reduce the vibration transmission, the gradiometers are mounted in the vacuum space of the helmet dewar with direct thermal contact with the liquid helium helmet. The reliquefier uses a 1.4 W pulse tube cryocooler with a remote motor, and a horizontal transfer tube with a downslope angle of 1°. The white noise of the system is 3.5 fTrms/√Hz (at 100 Hz). The vibration-induced peak at 1.4 Hz is 18 fTrms/√Hz averaged over the whole helmet array of 150 channels, which is the lowest among the reported values using reliquefier cooling and comparable to the noise peak cooled by conventional direct liquid helium cooling with axial gradiometers of the same baseline. The spontaneous brain activity signal showed nearly identical signal quality with the reliquefier turned on and off, and the reliquefier-based MEG system noise is well below the brain noise level.

High temperature superconductor dc-SQUID microscope with a soft magnetic flux guide

NASA Astrophysics Data System (ADS)

Poppe, U.; Faley, M. I.; Zimmermann, E.; Glaas, W.; Breunig, I.; Speen, R.; Jungbluth, B.; Soltner, H.; Halling, H.; Urban, K.

2004-05-01

A scanning SQUID microscope based on high-temperature superconductor (HTS) dc-SQUIDs was developed. An extremely soft magnetic amorphous foil was used to guide the flux from room temperature samples to the liquid-nitrogen-cooled SQUID sensor and back. The flux guide passes through the pick-up loop of the HTS SQUID, providing an improved coupling of magnetic flux of the object to the SQUID. The device measures the z component (direction perpendicular to the sample surface) of the stray field of the sample, which is rastered with submicron precision in the x-y direction by a motorized computer-controlled scanning stage. A lateral resolution better than 10 µm, with a field resolution of about 0.6 nT Hz-1/2 was achieved for the determination of the position of the current carrying thin wires. The presence of the soft magnetic foil did not significantly increase the flux noise of the SQUID.

Subranging technique using superconducting technology

DOEpatents

Gupta, Deepnarayan

2003-01-01

Subranging techniques using "digital SQUIDs" are used to design systems with large dynamic range, high resolution and large bandwidth. Analog-to-digital converters (ADCs) embodying the invention include a first SQUID based "coarse" resolution circuit and a second SQUID based "fine" resolution circuit to convert an analog input signal into "coarse" and "fine" digital signals for subsequent processing. In one embodiment, an ADC includes circuitry for supplying an analog input signal to an input coil having at least a first inductive section and a second inductive section. A first superconducting quantum interference device (SQUID) is coupled to the first inductive section and a second SQUID is coupled to the second inductive section. The first SQUID is designed to produce "coarse" (large amplitude, low resolution) output signals and the second SQUID is designed to produce "fine" (low amplitude, high resolution) output signals in response to the analog input signals.

Microwave SQUID Multiplexer for the Readout of Metallic Magnetic Calorimeters

NASA Astrophysics Data System (ADS)

Kempf, S.; Gastaldo, L.; Fleischmann, A.; Enss, C.

2014-06-01

We have realized a frequency-domain multiplexing technique for the readout of large metallic magnetic calorimeter detector arrays. It is based on non-hysteretic single-junction SQUIDs and allows for a simultaneous readout of hundreds or thousands of detectors by using a single cryogenic high electron mobility transistor amplifier and two coaxial cables that are routed from room-temperature to the detector array. We discuss the working principle of the multiplexer and present details about our prototype multiplexer design. We show that fabricated devices are fully operational and that characteristic SQUID parameters such as the input sensitivity of the SQUID or the resonance frequency of the readout circuit can be predicted with confidence. Our best device so far has shown a magnetic flux white noise level of 1.4 m which can in future be reduced by an optimization of the fabrication processes as well as an improved microwave readout system.

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.

Optical transmission modules for multi-channel superconducting quantum interference device readouts.

PubMed

Kim, Jin-Mok; Kwon, Hyukchan; Yu, Kwon-kyu; Lee, Yong-Ho; Kim, Kiwoong

2013-12-01

We developed an optical transmission module consisting of 16-channel analog-to-digital converter (ADC), digital-noise filter, and one-line serial transmitter, which transferred Superconducting Quantum Interference Device (SQUID) readout data to a computer by a single optical cable. A 16-channel ADC sent out SQUID readouts data with 32-bit serial data of 8-bit channel and 24-bit voltage data at a sample rate of 1.5 kSample/s. A digital-noise filter suppressed digital noises generated by digital clocks to obtain SQUID modulation as large as possible. One-line serial transmitter reformed 32-bit serial data to the modulated data that contained data and clock, and sent them through a single optical cable. When the optical transmission modules were applied to 152-channel SQUID magnetoencephalography system, this system maintained a field noise level of 3 fT/√Hz @ 100 Hz.

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

NASA Astrophysics Data System (ADS)

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

2017-05-01

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

Y1Ba2Cu3O(7-delta) thin film dc SQUIDs (superconducting quantum interference device)

NASA Astrophysics Data System (ADS)

Racah, Daniel

1991-03-01

Direct current superconducting quantum interferometers (SQUIDs) based on HTSC thin films have been measured and characterized. The thin films used were of different quality: (1) Granular films on Sapphire substrates, prepared either by e-gun evaporation, by laser ablation or by MOCVD (metal oxide chemical vapor deposition), (2) Epitaxial films on MgO substrates. Modulations of the voltage on the SQUIDs as a function of the applied flux have been observed in a wide range of temperatures. The nature of the modulation was found to be strongly dependent on the morphology of the film and on its critical current. The SQUIDs based on granular films were relatively noisy, hysteretic and with a complicated V-phi shape. Those devices based on low quality (lowIc) granular films could be measured only at low temperatures (much lower than 77 K). While those of higher quality (granular films with high Ic) could be measured near to the superconductive transition. The SQUID based on high quality epitaxial film was measured near Tc and showed an anomalous, time dependent behavior.

Spaceborne Gravity Gradiometers. Part 3: Instrument status and prospects

NASA Technical Reports Server (NTRS)

1984-01-01

Various technologies incorporated in the development of gravity gradiometers are demonstrated through descriptions of specific instruments. Concepts covered include: rotating, spherical, cryogenic, and superconducting gravity gradiometers with and without accelerometers. The application of superconducting cavity oscillators to mass-spring gradiometers, and cooperation of Italy's Piano Spaziale Nazionale with the Smithsonian Astrophysics Observatory in the design and development of a high sensitivity gradiometer are described. Schematics are provided for each instrument.

Implementing an ancilla-free 1→M economical phase-covariant quantum cloning machine with superconducting quantum-interference devices in cavity QED

NASA Astrophysics Data System (ADS)

Yu, Long-Bao; Zhang, Wen-Hai; Ye, Liu

2007-09-01

We propose a simple scheme to realize 1→M economical phase-covariant quantum cloning machine (EPQCM) with superconducting quantum interference device (SQUID) qubits. In our scheme, multi-SQUIDs are fixed into a microwave cavity by adiabatic passage for their manipulation. Based on this model, we can realize the EPQCM with high fidelity via adiabatic quantum computation.

Negative inductance SQUID qubit operating in a quantum regime

NASA Astrophysics Data System (ADS)

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

2018-04-01

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

Josephson Thermal Memory

NASA Astrophysics Data System (ADS)

Guarcello, Claudio; Solinas, Paolo; Braggio, Alessandro; Di Ventra, Massimiliano; Giazotto, Francesco

2018-01-01

We propose a superconducting thermal memory device that exploits the thermal hysteresis in a flux-controlled temperature-biased superconducting quantum-interference device (SQUID). This system reveals a flux-controllable temperature bistability, which can be used to define two well-distinguishable thermal logic states. We discuss a suitable writing-reading procedure for these memory states. The time of the memory writing operation is expected to be on the order of approximately 0.2 ns for a Nb-based SQUID in thermal contact with a phonon bath at 4.2 K. We suggest a noninvasive readout scheme for the memory states based on the measurement of the effective resonance frequency of a tank circuit inductively coupled to the SQUID. The proposed device paves the way for a practical implementation of thermal logic and computation. The advantage of this proposal is that it represents also an example of harvesting thermal energy in superconducting circuits.

Cold SQUIDs and hot samples

DOE Office of Scientific and Technical Information (OSTI.GOV)

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 magneticmore » 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.« less

Non-resonant interactions between superconducting circuits coupled through a dc-SQUID

NASA Astrophysics Data System (ADS)

Jin, X. Y.; Lecocq, F.; Cicak, K.; Kotler, S. S.; Peterson, G. A.; Teufel, J. D.; Aumentado, J.; Simmonds, R. W.

We use a flux-biased direct current superconducting quantum interference device (dc-SQUID) to generate non-resonant tunable interactions between transmon qubits and resonators modes. By modulating the flux to the dc-SQUID, we can create an interaction with variable coupling rates from zero to greater than 100 MHz. We explore this system experimentally and describe its operation. Parametric coupling is important for constructing larger coupled systems, useful for both quantum information architectures and quantum simulators.

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 approximately half with a gain in SNR of about four. Thus, we conclude from the performance of the prototype that it should be feasible to improve the babySQUID to detect cortical activity in infants in real time with high spatial resolution.

Investigation and optimization of low-frequency noise performance in readout electronics of dc superconducting quantum interference device

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Jing; Peter Grünberg Institute; Zhang, Yi

2014-05-15

We investigated and optimized the low-frequency noise characteristics of a preamplifier used for readout of direct current superconducting quantum interference devices (SQUIDs). When the SQUID output was detected directly using a room-temperature low-voltage-noise preamplifier, the low-frequency noise of a SQUID system was found to be dominated by the input current noise of the preamplifiers in case of a large dynamic resistance of the SQUID. To reduce the current noise of the preamplifier in the low-frequency range, we investigated the dependence of total preamplifier noise on the collector current and source resistance. When the collector current was decreased from 8.4 mAmore » to 3 mA in the preamplifier made of 3 parallel SSM2220 transistor pairs, the low-frequency total voltage noise of the preamplifier (at 0.1 Hz) decreased by about 3 times for a source resistance of 30 Ω whereas the white noise level remained nearly unchanged. Since the relative contribution of preamplifier's input voltage and current noise is different depending on the dynamic resistance or flux-to-voltage transfer of the SQUID, the results showed that the total noise of a SQUID system at low-frequency range can be improved significantly by optimizing the preamplifier circuit parameters, mainly the collector current in case of low-noise bipolar transistor pairs.« less

Investigation and optimization of low-frequency noise performance in readout electronics of dc superconducting quantum interference device

NASA Astrophysics Data System (ADS)

Zhao, Jing; Zhang, Yi; Lee, Yong-Ho; Krause, Hans-Joachim

2014-05-01

We investigated and optimized the low-frequency noise characteristics of a preamplifier used for readout of direct current superconducting quantum interference devices (SQUIDs). When the SQUID output was detected directly using a room-temperature low-voltage-noise preamplifier, the low-frequency noise of a SQUID system was found to be dominated by the input current noise of the preamplifiers in case of a large dynamic resistance of the SQUID. To reduce the current noise of the preamplifier in the low-frequency range, we investigated the dependence of total preamplifier noise on the collector current and source resistance. When the collector current was decreased from 8.4 mA to 3 mA in the preamplifier made of 3 parallel SSM2220 transistor pairs, the low-frequency total voltage noise of the preamplifier (at 0.1 Hz) decreased by about 3 times for a source resistance of 30 Ω whereas the white noise level remained nearly unchanged. Since the relative contribution of preamplifier's input voltage and current noise is different depending on the dynamic resistance or flux-to-voltage transfer of the SQUID, the results showed that the total noise of a SQUID system at low-frequency range can be improved significantly by optimizing the preamplifier circuit parameters, mainly the collector current in case of low-noise bipolar transistor pairs.

Research on Intelligent Control System of DC SQUID Magnetometer Parameters for Multi-channel System

NASA Astrophysics Data System (ADS)

Chen, Hua; Yang, Kang; Lu, Li; Kong, Xiangyan; Wang, Hai; Wu, Jun; Wang, Yongliang

2018-07-01

In a multi-channel SQUID measurement system, adjusting device parameters to optimal condition for all channels is time-consuming. In this paper, an intelligent control system is presented to determine the optimal working point of devices which is automatic and more efficient comparing to the manual one. An optimal working point searching algorithm is introduced as the core component of the control system. In this algorithm, the bias voltage V_bias is step scanned to obtain the maximal value of the peak-to-peak current value I_pp of the SQUID magnetometer modulation curve. We choose this point as the optimal one. Using the above control system, more than 30 weakly damped SQUID magnetometers with area of 5 × 5 mm^2 or 10 × 10 mm^2 are adjusted and a 36-channel magnetocardiography system perfectly worked in a magnetically shielded room. The average white flux noise is 15 {μ Φ }_0/Hz^{1/2}.

Direct current superconducting quantum interference device spectrometer for pulsed nuclear magnetic resonance and nuclear quadrupole resonance at frequencies up to 5 MHz

DOE Office of Scientific and Technical Information (OSTI.GOV)

TonThat, D.M.; Clarke, J.

1996-08-01

A spectrometer based on a dc superconducting quantum interference device (SQUID) has been developed for the direct detection of nuclear magnetic resonance (NMR) or nuclear quadrupole resonance (NQR) at frequencies up to 5 MHz. The sample is coupled to the input coil of the niobium-based SQUID via a nonresonant superconducting circuit. The flux locked loop involves the direct offset integration technique with additional positive feedback in which the output of the SQUID is coupled directly to a low-noise preamplifier. Precession of the nuclear quadrupole spins is induced by a magnetic field pulse with the feedback circuit disabled; subsequently, flux lockedmore » operation is restored and the SQUID amplifies the signal produced by the nuclear free induction signal. The spectrometer has been used to detect {sup 27}Al NQR signals in ruby (Al{sub 2}O{sub 3}[Cr{sup 3+}]) at 359 and 714 kHz. {copyright} {ital 1996 American Institute of Physics.}« less

Research on Intelligent Control System of DC SQUID Magnetometer Parameters for Multi-channel System

NASA Astrophysics Data System (ADS)

Chen, Hua; Yang, Kang; Lu, Li; Kong, Xiangyan; Wang, Hai; Wu, Jun; Wang, Yongliang

2018-03-01

In a multi-channel SQUID measurement system, adjusting device parameters to optimal condition for all channels is time-consuming. In this paper, an intelligent control system is presented to determine the optimal working point of devices which is automatic and more efficient comparing to the manual one. An optimal working point searching algorithm is introduced as the core component of the control system. In this algorithm, the bias voltage V_bias is step scanned to obtain the maximal value of the peak-to-peak current value I_pp of the SQUID magnetometer modulation curve. We choose this point as the optimal one. Using the above control system, more than 30 weakly damped SQUID magnetometers with area of 5 × 5 mm^2 or 10 × 10 mm^2 are adjusted and a 36-channel magnetocardiography system perfectly worked in a magnetically shielded room. The average white flux noise is 15 μΦ_0/Hz^{1/2}.

Development of a sensitive superconducting gravity gradiometer for geological and navigational applications

NASA Technical Reports Server (NTRS)

Paik, H. J.; Richard, J. P.

1986-01-01

A sensitive and stable gravity gradiometer would provide high resolution gravity measurements from space. The instrument could also provide precision tests of fundamental laws of physics and be applied to inertial guidance systems of the future. This report describes research on the superconducting gravity gradiometer program at the University of Maryland from July 1980 to July 1985. The report describes the theoretical and experimental work on a prototype superconducting gravity gradiometer. The design of an advanced three-axis superconducting gravity gradiometer is also discussed.

Nano Superconducting Quantum Interference device: A powerful tool for nanoscale investigations

NASA Astrophysics Data System (ADS)

Granata, Carmine; Vettoliere, Antonio

2016-02-01

The magnetic sensing at nanoscale level is a promising and interesting research topic of nanoscience. Indeed, magnetic imaging is a powerful tool for probing biological, chemical and physical systems. The study of small spin cluster, like magnetic molecules and nanoparticles, single electron, cold atom clouds, is one of the most stimulating challenges of applied and basic research of the next years. In particular, the magnetic nanoparticle investigation plays a fundamental role for the modern material science and its relative technological applications like ferrofluids, magnetic refrigeration and biomedical applications, including drug delivery, hyper-thermia cancer treatment and magnetic resonance imaging contrast-agent. Actually, one of the most ambitious goals of the high sensitivity magnetometry is the detection of elementary magnetic moment or spin. In this framework, several efforts have been devoted to the development of a high sensitivity magnetic nanosensor pushing sensing capability to the individual spin level. Among the different magnetic sensors, Superconducting QUantum Interference Devices (SQUIDs) exhibit an ultra high sensitivity and are widely employed in numerous applications. Basically, a SQUID consists of a superconducting ring (sensitive area) interrupted by two Josephson junctions. In the recent years, it has been proved that the magnetic response of nano-objects can be effectively measured by using a SQUID with a very small sensitive area (nanoSQUID). In fact, the sensor noise, expressed in terms of the elementary magnetic moment (spin or Bohr magneton), is linearly dependent on the SQUID loop side length. For this reason, SQUIDs have been progressively miniaturized in order to improve the sensitivity up to few spin per unit of bandwidth. With respect to other techniques, nanoSQUIDs offer the advantage of direct measurement of magnetization changes in small spin systems. In this review, we focus on nanoSQUIDs and its applications. In particular, we will discuss the motivations, the theoretical aspects, the fabrication techniques, the different nanoSQUIDs and the relative nanoscale applications.

Potential aerospace applications of high temperature superconductors

NASA Technical Reports Server (NTRS)

Selim, Raouf

1994-01-01

The recent discovery of High Temperature Superconductors (HTS) with superconducting transition temperature, T(sub c), above the boiling point of liquid nitrogen has opened the door for using these materials in new and practical applications. These materials have zero resistance to electric current, have the capability of carrying large currents and as such have the potential to be used in high magnetic field applications. One of the space applications that can use superconductors is electromagnetic launch of payloads to low-earth-orbit. An electromagnetic gun-type launcher can be used in small payload systems that are launched at very high velocity, while sled-type magnetically levitated launcher can be used to launch larger payloads at smaller velocities. Both types of launchers are being studied by NASA and the aerospace industry. The use of superconductors will be essential in any of these types of launchers in order to produce the large magnetic fields required to obtain large thrust forces. Low Temperature Superconductor (LTS) technology is mature enough and can be easily integrated in such systems. As for the HTS, many leading companies are currently producing HTS coils and magnets that potentially can be mass-produced for these launchers. It seems that designing and building a small-scale electromagnetic launcher is the next logical step toward seriously considering this method for launching payloads into low-earth-orbit. A second potential application is the use of HTS to build sensitive portable devices for the use in Non Destructive Evaluation (NDE). Superconducting Quantum Interference Devices (SQUID's) are the most sensitive instruments for measuring changes in magnetic flux. By using HTS in SQUID's, one will be able to design a portable unit that uses liquid nitrogen or a cryocooler pump to explore the use of gradiometers or magnetometers to detect deep cracks or corrosion in structures. A third use is the replacement of Infra-Red (IR) sensor leads on Earth Orbit Systems (EOS) with HTS leads. IR detectors on these EOS missions are cooled to a 4.2K to improve their signal to noise ratio. They are connected to data acquisitions systems using manganin wires (low thermal conductors) to reduce the heat load on the cryogen. Replacing these wires with HTS leads will increase the lifetime of these missions by about 50 percent. This is a promising application that is ready for actual implementation on such systems. The analysis also show that an the number of IR detectors increase in larger EOS systems, substantial increase in the lifetime of each mission will be realized by using HTS leads instead of the manganin ones.

Gravity gradiometry developments at Lockheed Martin

NASA Astrophysics Data System (ADS)

Difrancesco, D.

2003-04-01

Lockheed Martin has developed and fielded multiple configurations of the rotating accelerometer gravity gradiometer instrument. Applications for both static and moving-base measurements have been demonstrated for a variety of scenarios, including vehicle navigation, hydrocarbon exploration, mineral exploration, reservoir monitoring, underground void detection and treaty monitoring and compliance. The most recent systems built by Lockheed Martin extend the performance range of the early 4-accelerometer gradiometers by adding a second complement of four accelerometers. This achieves the benefit of lower instrument noise and improved frequency response (wider bandwidth) for stringent application scenarios. A summary of the gradiometer development history, functional concepts, instrument and system operation, and demonstrated performance will be presented. Development Background The U. S. Air Force Geophysics Laboratory (AFGL; now AFRL) instituted a program in 1982 to develop and field a moving base gradiometer system that could be used both on land and in the air. The result was the Gravity Gradiometer Survey System (GGSS) which first demonstrated the ability to make airborne gravity gradient measurements in 1987 (Jekeli, 1988). At the same time, the U.S. Navy began development of the Gravity Sensors System (GSS) for use on the Fleet Ballistic Submarine Trident II navigation subsystem. This military background paved the way for commercial uses of gravity gradiometry. Both the GSS and GGSS employed a first generation gravity gradiometer instrument (GGI), which was comprised of four accelerometers mounted on a rotating disk. The details of the GGI operation are further described in the work by Gerber and Hofmeyer (Gerber, 1978 and Hofmeyer, 1994). Recent Advancements in Gradiometer Instrumentation With the instrumentation experience gained through such programs as GSS and GGSS, Lockheed Martin embarked upon an ambitious effort in the early 1990's to further improve the performance of the rotating accelerometer gradiometer design. Under funding from the Defense Threat Reduction Agency (DTRA), a "next generation" gradiometer was developed for the specific purpose of identifying treaty-limited items in arms control inspection scenarios. The result was the Arms Control Verification Gravity Gradiometer (ACVGG), which comprised two complements of four accelerometers to provide for lower noise and improved frequency response. Following the advancements made with the ACVGG, Lockheed Martin began development of an airborne gradiometer to be used for mineral exploration. The Airborne Gravity Gradiometer (AGG) is installed into an inertially stabilized platform for use in a geophysical survey aircraft. The AGG has been successfully deployed in the BHP Billiton Falcon™ system (van Leeuwen, 2000) for detection and identification of mineral targets. The most recent gradiometer development by Lockheed Martin is the Land Gradiometer System for time-lapse measurement (4D), designed and tested in 2000. In this configuration, the gradiometer is employed in a static mode, without a stabilized platform. The system positions the gradiometer at unique heading and tilt combinations to reduce the influence of bias drift and the coupling of horizontal gradients into the measurement (Feldman, 2000). The gradiometer is used to make measurements at discrete points in time (typically months apart) to monitor the time-varying signal associated with such processes as steam flooding, water flooding or gas injection for enhanced oil recovery (Talwani, 2001). The system also has been deployed to make 3D surveys over targets of interest. Conclusions Significant advancements in gradiometer instrumentation have been realized in recent years. Instrument and system performance has improved by nearly two orders of magnitude and new applications have emerged that span a broad range of geophysical interest. References (1)Jekeli, C., 1988, "The Gravity Gradiometer Survey System (GGSS)", EOS, 69, 105 and 116-117 (2)Gerber, M.A., 1978, "Gravity gradiometry - something new in inertial navigation", Astronautics &Aeronautics, 18-26. (3)Hofmeyer, G.M. and Affleck, C.A., 1994, "Rotating Accelerometer Gradiometer", US Patent 5,357,802. (4)Van Leeuwen, E.H., 2000, "BHP develops world's first airborne gravity gradiometer for mineral exploration", Preview 86, 28-30. (5)Feldman, W.K., et al, 2000, "System and Process for Optimizing Gravity Gradiometer Measurements", US Patent 6,125,698. (6)Talwani, M., et al, 2001, "System enables time lapse gradiometry", American Oil &Gas Reporter 44, 101-108

Parasitic effects in superconducting quantum interference device-based radiation comb generators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bosisio, R., E-mail: riccardo.bosisio@nano.cnr.it; NEST, Instituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa; Giazotto, F., E-mail: giazotto@sns.it

2015-12-07

We study several parasitic effects on the implementation of a Josephson radiation comb generator based on a dc superconducting quantum interference device (SQUID) driven by an external magnetic field. This system can be used as a radiation generator similarly to what is done in optics and metrology, and allows one to generate up to several hundreds of harmonics of the driving frequency. First we take into account how the assumption of a finite loop geometrical inductance and junction capacitance in each SQUID may alter the operation of the devices. Then, we estimate the effect of imperfections in the fabrication ofmore » an array of SQUIDs, which is an unavoidable source of errors in practical situations. We show that the role of the junction capacitance is, in general, negligible, whereas the geometrical inductance has a beneficial effect on the performance of the device. The errors on the areas and junction resistance asymmetries may deteriorate the performance, but their effect can be limited to a large extent by a suitable choice of fabrication parameters.« less

Implementing two optimal economical quantum cloning with superconducting quantum interference devices in a cavity

NASA Astrophysics Data System (ADS)

Ye, Liu; Hu, GuiYu; Li, AiXia

2011-01-01

We propose a unified scheme to implement the optimal 1 → 3 economical phase-covariant quantum cloning and optimal 1 → 3 economical real state cloning with superconducting quantum interference devices (SQUIDs) in a cavity. During this process, no transfer of quantum information between the SQUIDs and cavity is required. The cavity field is only virtually excited. The scheme is insensitive to cavity decay. Therefore, the scheme can be experimentally realized in the range of current cavity QED techniques.

Novel Approaches to Quantum Computation Using Solid State Qubits

DTIC Science & Technology

2007-12-31

hysteretic DC-SQUIDs, Phys. Rev. B 71, 220509(R) (2005). 18. C.-P. Yang and S. Han, Generation of Greenberger-Horne- Zeilinger entangled states with three SQUID...Horne- Zeilinger entangled states with multiple superconducting quantum interference device qubits/atoms in cavity QED, Phys. Rev. A 70, 062323 (2004

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

PubMed Central

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

2015-01-01

Superconducting quantum interference devices (SQUIDs) are accepted as one of the highest magnetic field sensitive probes. There are increasing demands to image local magnetic fields to explore spin properties and current density distributions in a two-dimensional layer of semiconductors or superconductors. Nano-SQUIDs have recently attracting much interest for high spatial resolution measurements in nanometer-scale samples. Whereas weak-link Dayem Josephson junction nano-SQUIDs are suitable to miniaturization, hysteresis in current-voltage (I-V) characteristics that is often observed in Dayem Josephson junction is not desirable for a scanning microscope. Here we report on our development of a weak-link nano-SQUIDs scanning microscope with small hysteresis in I-V curve and on reconstructions of two-dimensional current density vector in two-dimensional electron gas from measured magnetic field. PMID:26459874

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

NASA Astrophysics Data System (ADS)

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

2015-10-01

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

An EM System With Dramatic Multi-Axis Transmitter and Tensor Gradiometer Receiver

DTIC Science & Technology

2011-06-01

Thus, the main difference between the spatial behavior of target anomalies measured with a magnetometer and those we measured with an EM system is in...current efforts include the development of tensor magnetic gradiometers based on triaxial fluxgate technology by the USGS (Snyder & Bracken, Development...Superconducting gradiometer/ Magnetometer Arrays and a Novel Signal Processing Technique. IEEE Trans. on Magnetics, MAG-11(2), 701-707. EM Tensor Gradiometer

Magnetic Sensitivity of AlMn TESes and Shielding Considerations for Next-Generation CMB Surveys

NASA Astrophysics Data System (ADS)

Vavagiakis, E. M.; Henderson, S. W.; Zheng, K.; Cho, H.-M.; Cothard, N. F.; Dober, B.; Duff, S. M.; Gallardo, P. A.; Hilton, G.; Hubmayr, J.; Irwin, K. D.; Koopman, B. J.; Li, D.; Nati, F.; Niemack, M. D.; Reintsema, C. D.; Simon, S.; Stevens, J. R.; Suzuki, A.; Westbrook, B.

2018-05-01

In the next decade, new ground-based cosmic microwave background (CMB) experiments such as Simons Observatory, CCAT-prime, and CMB-S4 will increase the number of detectors observing the CMB by an order of magnitude or more, dramatically improving our understanding of cosmology and astrophysics. These projects will deploy receivers with as many as hundreds of thousands of transition edge sensor (TES) bolometers coupled to superconducting quantum interference device (SQUID)-based readout systems. It is well known that superconducting devices such as TESes and SQUIDs are sensitive to magnetic fields. However, the effects of magnetic fields on TESes are not easily predicted due to the complex behavior of the superconducting transition, which motivates direct measurements of the magnetic sensitivity of these devices. We present comparative four-lead measurements of the critical temperature versus applied magnetic field of AlMn TESes varying in geometry, doping, and leg length, including Advanced ACT and POLARBEAR-2/Simons Array bolometers. MoCu ACTPol TESes are also tested and are found to be more sensitive to magnetic fields than the AlMn devices. We present an observation of weak-link-like behavior in AlMn TESes at low critical currents. We also compare measurements of magnetic sensitivity for time division multiplexing SQUIDs and frequency division multiplexing microwave (μ MUX) rf-SQUIDs. We discuss the implications of our measurements on the magnetic shielding required for future experiments that aim to map the CMB to near-fundamental limits.

Sensitive Superconducting Gravity Gradiometer Constructed with Levitated Test Masses

NASA Astrophysics Data System (ADS)

Griggs, C. E.; Moody, M. V.; Norton, R. S.; Paik, H. J.; Venkateswara, K.

2017-12-01

We demonstrate basic operations of a two-component superconducting gravity gradiometer (SGG) that is constructed with a pair of magnetically levitated test masses coupled to superconducting quantum-interference devices. A design that gives a potential sensitivity of 1.4 ×10-4 E Hz-1 /2 (1 E ≡10-9 s-2 ) in the frequency band of 1 to 50 mHz and better than 2 ×10-5 E Hz-1 /2 between 0.1 and 1 mHz for a compact tensor SGG that fits within a 22-cm-diameter sphere. The SGG has the capability of rejecting the platform acceleration and jitter in all 6 degrees of freedom to one part in 109 . Such an instrument has applications in precision tests of fundamental laws of physics, earthquake early warning, and gravity mapping of Earth and the planets.

Research relative to the development of a cryogenic microwave cavity gradiometer for orbital use

NASA Technical Reports Server (NTRS)

Grossi, M. D.

1984-01-01

The noncryogenic, single axis, gravity gradiometer which is characterized by a sensitivity of the order of 10 to the minus 2 power Eovos Units in a few sec integration time was investigated. The prototype of testing gradiometer on the earth surface by the free fall in vacuo method was expanded. An existing free fall tower facility and the possibility of adding inside the falling elevator cabin an air tight, sealed, cylindrical container with inside pressure or = -0.001 Torr were examined to test the gradiometer in free fall conditions inside this evacuated container. Earth's gravity anomalies are simulated with masses of suitable shape, weight, and location. The attitude of the falling gradiometer is monitored by a three axis gyro package mounted on the instrument package. It is concluded that the free fall testing of the gradiometer is both feasible and practical.

RAPID COMMUNICATION: DC superconducting quantum interference devices fabricated using bicrystal grain boundary junctions in Co-doped BaFe2As2 epitaxial films

NASA Astrophysics Data System (ADS)

Katase, Takayoshi; Ishimaru, Yoshihiro; Tsukamoto, Akira; Hiramatsu, Hidenori; Kamiya, Toshio; Tanabe, Keiichi; Hosono, Hideo

2010-08-01

DC superconducting quantum interference devices (dc-SQUIDs) were fabricated in Co-doped BaFe2As2 epitaxial films on (La, Sr)(Al, Ta)O3 bicrystal substrates with 30° misorientation angles. The 18 × 8 µm2 SQUID loop with an estimated inductance of 13 pH contained two 3 µm wide grain boundary junctions. The voltage-flux characteristics clearly exhibited periodic modulations with ΔV = 1.4 µV at 14 K, while the intrinsic flux noise of dc-SQUIDs was 7.8 × 10 - 5 Φ0 Hz - 1/2 above 20 Hz. The rather high flux noise is mainly attributed to the small voltage modulation depth which results from the superconductor-normal-metal-superconductor junction nature of the bicrystal grain boundary.

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.

New Matching Method for Accelerometers in Gravity Gradiometer

PubMed Central

Wei, Hongwei; Wu, Meiping; Cao, Juliang

2017-01-01

The gravity gradiometer is widely used in mineral prospecting, including in the exploration of mineral, oil and gas deposits. The mismatch of accelerometers adversely affects the measuring precision of rotating accelerometer-based gravity gradiometers. Several strategies have been investigated to address the imbalance of accelerometers in gradiometers. These strategies, however, complicate gradiometer structures because feedback loops and re-designed accelerometers are needed in these strategies. In this paper, we present a novel matching method, which is based on a new configuration of accelerometers in a gravity gradiometer. In the new configuration, an angle was introduced between the measurement direction of the accelerometer and the spin direction. With the introduced angle, accelerometers could measure the centrifugal acceleration generated by the rotating disc. Matching was realized by updating the scale factors of the accelerometers with the help of centrifugal acceleration. Further simulation computations showed that after adopting the new matching method, signal-to-noise ratio improved from −41 dB to 22 dB. Compared with other matching methods, our method is more flexible and costs less. The matching accuracy of this new method is similar to that of other methods. Our method provides a new idea for matching methods in gravity gradiometer measurement. PMID:28757584

Sensitive Spin Detection Using An On-Chip Squid-Waveguide Resonator

NASA Astrophysics Data System (ADS)

Yue, Guang

Quantum computing gives novel way of computing using quantum mechanics, which furthers human knowledge and has exciting applications. Quantum systems with diluted spins such as rare earth ions hosted in single crystal, molecule-based magnets etc. are promising qubits candidates to form the basis of a quantum computer. High sensitivity measurement and coherent control of these spin systems are crucial for their practical usage as qubits. The micro-SQUID (direct-current micrometer-sized Superconducting QUantum Interference Device) is capable to measure magnetization of spin system with high sensitivity. For example, the micro-SQUID technique can measure magnetic moments as small as several thousand muB as shown by the study of [W. Wernsdorfer, Supercond. Sci. Technol. 22, 064013 (2009)]. Here we develop a novel on-chip setup that combines the micro-SQUID sensitivity with microwave excitation. Such setup can be used for electron spin resonance measurements or coherent control of spins utilizing the high sensitivity of micro-SQUID for signal detection. To build the setup, we studied the fabrication process of the micro-SQUID, which is made of weak-linked Josephson junctions. The SQUID as a detector is integrated on the same chip with a shorted coplanar waveguide, so that the microwave pulses can be applied through the waveguide to excite the sample for resonance measurements. The whole device is plasma etched from a thin (˜ 20nm) niobium film, so that the SQUID can work at in large in-plane magnetic fields of several tesla. In addition, computer simulations are done to find the best design of the waveguide such that the microwave excitation field is sufficiently strong and uniformly applied to the sample. The magnetization curve of Mn12 molecule-based magnet sample is measured to prove the proper working of the micro-SQUID. Electron spin resonance measurement is done on the setup for gadolinium ions diluted in a CaWO4 single crystal. The measurement shows clear evidence of the resonance signal from the 1st transition of the gadolinium ions' energy levels, which shows the setup is successfully built. Due to the high sensitivity of micro-SQUID and the ability to concentrate microwave energy in small areas of the chip, this setup can detect signals from a small number of spins (107) in a small volume (several mum 3).

Ultra low noise YBa{sub 2}Cu{sub 3}O{sub 7−δ} nano superconducting quantum interference devices implementing nanowires

DOE Office of Scientific and Technical Information (OSTI.GOV)

Arpaia, R.; CNR-SPIN, Dipartimento di Scienze Fisiche, Università degli Studi di Napoli “Federico II,” I-80125 Napoli; Arzeo, M.

2014-02-17

We present results on ultra low noise YBa{sub 2}Cu{sub 3}O{sub 7–δ} (YBCO) nano Superconducting QUantum Interference Devices (nanoSQUIDs). To realize such devices, we implemented high quality YBCO nanowires, working as weak links between two electrodes. We observe critical current modulation as a function of an externally applied magnetic field in the full temperature range below the transition temperature T{sub C}. The white flux noise below 1μΦ{sub 0}/√(Hz) at T=8 K makes our nanoSQUIDs very attractive for the detection of small spin systems.

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.

Active Tensor Magnetic Gradiometer System

DTIC Science & Technology

2007-11-01

Modify Forward Computer Models .............................................................................................2 Modify TMGS Simulator...active magnetic gradient measurement system are based upon the existing tensor magnetic gradiometer system ( TMGS ) developed under project MM-1328...Magnetic Gradiometer System ( TMGS ) for UXO Detection, Imaging, and Discrimination.” The TMGS developed under MM-1328 was successfully tested at the

Squid detected NMR and MRI at ultralow fields

DOEpatents

Clarke, John [Berkeley, CA; McDermott, Robert [Louisville, CO; Pines, Alexander [Berkeley, CA; Trabesinger, Andreas Heinz [CH-8006 Zurich, CH

2007-05-15

Nuclear magnetic resonance (NMR) signals are detected in microtesla fields. Prepolarization in millitesla fields is followed by detection with an untuned dc superconducting quantum interference device (SQUID) magnetometer. Because the sensitivity of the SQUID is frequency independent, both signal-to-noise ratio (SNR) and spectral resolution are enhanced by detecting the NMR signal in extremely low magnetic fields, where the NMR lines become very narrow even for grossly inhomogeneous measurement fields. MRI in ultralow magnetic field is based on the NMR at ultralow fields. Gradient magnetic fields are applied, and images are constructed from the detected NMR signals.

Squid detected NMR and MRI at ultralow fields

DOEpatents

Clarke, John; McDermott, Robert; Pines, Alexander; Trabesinger, Andreas Heinz

2006-05-30

Nuclear magnetic resonance (NMR) signals are detected in microtesla fields. Prepolarization in millitesla fields is followed by detection with an untuned dc superconducting quantum interference device (SQUID) magnetometer. Because the sensitivity of the SQUID is frequency independent, both signal-to-noise ratio (SNR) and spectral resolution are enhanced by detecting the NMR signal in extremely low magnetic fields, where the NMR lines become very narrow even for grossly inhomogeneous measurement fields. MRI in ultralow magnetic field is based on the NMR at ultralow fields. Gradient magnetic fields are applied, and images are constructed from the detected NMR signals.

Squid detected NMR and MRI at ultralow fields

DOEpatents

Clarke, John [Berkeley, CA; Pines, Alexander [Berkeley, CA; McDermott, Robert F [Monona, WI; Trabesinger, Andreas H [London, GB

2008-12-16

Nuclear magnetic resonance (NMR) signals are detected in microtesla fields. Prepolarization in millitesla fields is followed by detection with an untuned dc superconducting quantum interference device (SQUID) magnetometer. Because the sensitivity of the SQUID is frequency independent, both signal-to-noise ratio (SNR) and spectral resolution are enhanced by detecting the NMR signal in extremely low magnetic fields, where the NMR lines become very narrow even for grossly inhomogeneous measurement fields. MRI in ultralow magnetic field is based on the NMR at ultralow fields. Gradient magnetic fields are applied, and images are constructed from the detected NMR signals.

SQUID detected NMR and MRI at ultralow fields

DOEpatents

Clarke, John; McDermott, Robert; Pines, Alexander; Trabesinger, Andreas Heinz

2006-10-03

Nuclear magnetic resonance (NMR) signals are detected in microtesla fields. Prepolarization in millitesla fields is followed by detection with an untuned dc superconducting quantum interference device (SQUID) magnetometer. Because the sensitivity of the SQUID is frequency independent, both signal-to-noise ratio (SNR) and spectral resolution are enhanced by detecting the NMR signal in extremely low magnetic fields, where the NMR lines become very narrow even for grossly inhomogeneous measurement fields. MRI in ultralow magnetic field is based on the NMR at ultralow fields. Gradient magnetic fields are applied, and images are constructed from the detected NMR signals.

NMR/MRI with hyperpolarized gas and high Tc SQUID

DOEpatents

Schlenga, Klaus; de Souza, Ricardo E.; Wong-Foy, Annjoe; Clarke, John; Pines, Alexander

2000-01-01

A method and apparatus for the detection of nuclear magnetic resonance (NMR) signals and production of magnetic resonance imaging (MRI) from samples combines the use of hyperpolarized inert gases to enhance the NMR signals from target nuclei in a sample and a high critical temperature (Tc) superconducting quantum interference device (SQUID) to detect the NMR signals. The system operates in static magnetic fields of 3 mT or less (down to 0.1 mT), and at temperatures from liquid nitrogen (77K) to room temperature. Sample size is limited only by the size of the magnetic field coils and not by the detector. The detector is a high Tc SQUID magnetometer designed so that the SQUID detector can be very close to the sample, which can be at room temperature.

Fabrication and characterization of hybrid Nb-YBCO dc SQUIDs

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

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

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

NASA Astrophysics Data System (ADS)

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

2015-10-01

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

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 performance required for the future development of a large-scale astronomical instrument.

Current-induced SQUID behavior of superconducting Nb nano-rings

NASA Astrophysics Data System (ADS)

Sharon, Omri J.; Shaulov, Avner; Berger, Jorge; Sharoni, Amos; Yeshurun, Yosef

2016-06-01

The critical temperature in a superconducting ring changes periodically with the magnetic flux threading it, giving rise to the well-known Little-Parks magnetoresistance oscillations. Periodic changes of the critical current in a superconducting quantum interference device (SQUID), consisting of two Josephson junctions in a ring, lead to a different type of magnetoresistance oscillations utilized in detecting extremely small changes in magnetic fields. Here we demonstrate current-induced switching between Little-Parks and SQUID magnetoresistance oscillations in a superconducting nano-ring without Josephson junctions. Our measurements in Nb nano-rings show that as the bias current increases, the parabolic Little-Parks magnetoresistance oscillations become sinusoidal and eventually transform into oscillations typical of a SQUID. We associate this phenomenon with the flux-induced non-uniformity of the order parameter along a superconducting nano-ring, arising from the superconducting leads (‘arms’) attached to it. Current enhanced phase slip rates at the points with minimal order parameter create effective Josephson junctions in the ring, switching it into a SQUID.

Superconducting Quantum Interferometers for Nondestructive Evaluation

PubMed Central

Kostyurina, E. A.; Kalashnikov, K. V.; Maslennikov, Yu. V.; Koshelets, V. P.

2017-01-01

We review stationary and mobile systems that are used for the nondestructive evaluation of room temperature objects and are based on superconducting quantum interference devices (SQUIDs). The systems are optimized for samples whose dimensions are between 10 micrometers and several meters. Stray magnetic fields from small samples (10 µm–10 cm) are studied using a SQUID microscope equipped with a magnetic flux antenna, which is fed through the walls of liquid nitrogen cryostat and a hole in the SQUID’s pick-up loop and returned sidewards from the SQUID back to the sample. The SQUID microscope does not disturb the magnetization of the sample during image recording due to the decoupling of the magnetic flux antenna from the modulation and feedback coil. For larger samples, we use a hand-held mobile liquid nitrogen minicryostat with a first order planar gradiometric SQUID sensor. Low-Tc DC SQUID systems that are designed for NDE measurements of bio-objects are able to operate with sufficient resolution in a magnetically unshielded environment. High-Tc DC SQUID magnetometers that are operated in a magnetic shield demonstrate a magnetic field resolution of ~4 fT/√Hz at 77 K. This sensitivity is improved to ~2 fT/√Hz at 77 K by using a soft magnetic flux antenna. PMID:29210980

Simultaneous readout of 128 X-ray and gamma-ray transition-edge microcalorimeters using microwave SQUID multiplexing

NASA Astrophysics Data System (ADS)

Mates, J. A. B.; Becker, D. T.; Bennett, D. A.; Dober, B. J.; Gard, J. D.; Hays-Wehle, J. P.; Fowler, J. W.; Hilton, G. C.; Reintsema, C. D.; Schmidt, D. R.; Swetz, D. S.; Vale, L. R.; Ullom, J. N.

2017-08-01

The number of elements in most cryogenic sensor arrays is limited by the technology available to multiplex signals from the arrays into a smaller number of wires and readout amplifiers. The largest demonstrated arrays of transition-edge sensor (TES) microcalorimeters contain roughly 250 detectors and use time-division multiplexing with Superconducting Quantum Interference Devices (SQUIDs). The bandwidth limits of this technology constrain the number of sensors per amplifier chain, a quantity known as the multiplexing factor, to several 10s. With microwave SQUID multiplexing, we can expand the readout bandwidth and enable much larger multiplexing factors. While microwave SQUID multiplexing of TES microcalorimeters has been previously demonstrated with small numbers of detectors, we now present a fully scalable demonstration in which 128 TES detectors are read out on a single pair of coaxial cables.

Large voltage modulation in superconducting quantum interference devices with submicron-scale step-edge junctions

NASA Astrophysics Data System (ADS)

Lam, Simon K. H.

2017-09-01

A promising direction to improve the sensitivity of a SQUID is to increase its junction's normal resistance value, Rn, as the SQUID modulation voltage scales linearly with Rn. As a first step to develop highly sensitive single layer SQUID, submicron scale YBCO grain boundary step edge junctions and SQUIDs with large Rn were fabricated and studied. The step-edge junctions were reduced to submicron scale to increase their Rn values using focus ion beam, FIB and the measurement of transport properties were performed from 4.3 to 77 K. The FIB induced deposition layer proves to be effective to minimize the Ga ion contamination during the FIB milling process. The critical current-normal resistance value of submicron junction at 4.3 K was found to be 1-3 mV, comparable to the value of the same type of junction in micron scale. The submicron junction Rn value is in the range of 35-100 Ω, resulting a large SQUID modulation voltage in a wide temperature range. This performance promotes further investigation of cryogen-free, high field sensitivity SQUID applications at medium low temperature, e.g. at 40-60 K.

SQUIDs in biomagnetism: a roadmap towards improved healthcare

NASA Astrophysics Data System (ADS)

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

2016-11-01

Globally, the demand for improved health care delivery while managing escalating costs is a major challenge. Measuring the biomagnetic fields that emanate from the human brain already impacts the treatment of epilepsy, brain tumours and other brain disorders. This roadmap explores how superconducting technologies are poised to impact health care. Biomagnetism is the study of magnetic fields of biological origin. Biomagnetic fields are typically very weak, often in the femtotesla range, making their measurement challenging. The earliest in vivo human measurements were made with room-temperature coils. In 1963, Baule and McFee (1963 Am. Heart J. 55 95-6) reported the magnetic field produced by electric currents in the heart (‘magnetocardiography’), and in 1968, Cohen (1968 Science 161 784-6) described the magnetic field generated by alpha-rhythm currents in the brain (‘magnetoencephalography’). Subsequently, in 1970, Cohen et al (1970 Appl. Phys. Lett. 16 278-80) reported the recording of a magnetocardiogram using a Superconducting QUantum Interference Device (SQUID). Just two years later, in 1972, Cohen (1972 Science 175 664-6) described the use of a SQUID in magnetoencephalography. These last two papers set the scene for applications of SQUIDs in biomagnetism, the subject of this roadmap. The SQUID is a combination of two fundamental properties of superconductors. The first is flux quantization—the fact that the magnetic flux Φ in a closed superconducting loop is quantized in units of the magnetic flux quantum, Φ0 ≡ h/2e, ≈ 2.07 × 10-15 Tm2 (Deaver and Fairbank 1961 Phys. Rev. Lett. 7 43-6, Doll R and Näbauer M 1961 Phys. Rev. Lett. 7 51-2). Here, h is the Planck constant and e the elementary charge. The second property is the Josephson effect, predicted in 1962 by Josephson (1962 Phys. Lett. 1 251-3) and observed by Anderson and Rowell (1963 Phys. Rev. Lett. 10 230-2) in 1963. The Josephson junction consists of two weakly coupled superconductors separated by a tunnel barrier or other weak link. A tiny electric current is able to flow between the superconductors as a supercurrent, without developing a voltage across them. At currents above the ‘critical current’ (maximum supercurrent), however, a voltage is developed. In 1964, Jaklevic et al (1964 Phys. Rev. Lett. 12 159-60) observed quantum interference between two Josephson junctions connected in series on a superconducting loop, giving birth to the dc SQUID. The essential property of the SQUID is that a steady increase in the magnetic flux threading the loop causes the critical current to oscillate with a period of one flux quantum. In today’s SQUIDs, using conventional semiconductor readout electronics, one can typically detect a change in Φ corresponding to 10-6 Φ0 in one second. Although early practical SQUIDs were usually made from bulk superconductors, for example, niobium or Pb-Sn solder blobs, today’s devices are invariably made from thin superconducting films patterned with photolithography or even electron lithography. An extensive description of SQUIDs and their applications can be found in the SQUID Handbooks (Clarke and Braginski 2004 Fundamentals and Technology of SQUIDs and SQUID Systems vol I (Weinheim, Germany: Wiley-VCH), Clarke and Braginski 2006 Applications of SQUIDs and SQUID Systems vol II (Weinheim, Germany: Wiley-VCH)). The roadmap begins (chapter 1) with a brief review of the state-of-the-art of SQUID-based magnetometers and gradiometers for biomagnetic measurements. The magnetic field noise referred to the pick-up loop is typically a few fT Hz-1/2, often limited by noise in the metallized thermal insulation of the dewar rather than by intrinsic SQUID noise. The authors describe a pathway to achieve an intrinsic magnetic field noise as low as 0.1 fT Hz-1/2, approximately the Nyquist noise of the human body. They also descibe a technology to defeat dewar noise. Chapter 2 reviews the neuroscientific and clinical use of magnetoencephalography (MEG), by far the most widespread application of biomagnetism with systems containing typically 300 sensors cooled to liquid-helium temperature, 4.2 K. Two important clinical applications are presurgical mapping of focal epilepsy and of eloquent cortex in brain-tumor patients. Reducing the sensor-to-brain separation and the system noise level would both improve spatial resolution. The very recent commercial innovation that replaces the need for frequent manual transfer of liquid helium with an automated system that collects and liquefies the gas and transfers the liquid to the dewar will make MEG systems more accessible. A highly promising means of placing the sensors substantially closer to the scalp for MEG is to use high-transition-temperature (high-T c) SQUID sensors and flux transformers (chapter 3). Operation of these devices at liquid-nitrogen temperature, 77 K, enables one to minimize or even omit metallic thermal insulation between the sensors and the dewar. Noise levels of a few fT Hz-1/2 have already been achieved, and lower values are likely. The dewars can be made relatively flexible, and thus able to be placed close to the skull irrespective of the size of the head, potentially providing higher spatial resolution than liquid-helium based systems. The successful realization of a commercial high-T c MEG system would have a major commercial impact. Chapter 4 introduces the concept of SQUID-based ultra-low-field magnetic resonance imaging (ULF MRI) operating at typically several kHz, some four orders of magnitude lower than conventional, clinical MRI machines. Potential advantages of ULF MRI include higher image contrast than for conventional MRI, enabling methodologies not currently available. Examples include screening for cancer without a contrast agent, imaging traumatic brain injury (TBI) and degenerative diseases such as Alzheimer’s, and determining the elapsed time since a stroke. The major current problem with ULF MRI is that its signal-to-noise ratio (SNR) is low compared with high-field MRI. Realistic solutions to this problem are proposed, including implementing sensors with a noise level of 0.1 fT Hz-1/2. A logical and exciting prospect (chapter 5) is to combine MEG and ULF MRI into a single system in which both signal sources are detected with the same array of SQUIDs. A prototype system is described. The combination of MEG and ULF MRI allows one to obtain structural images of the head concurrently with the recording of brain activity. Since all MEG images require an MRI to determine source locations underlying the MEG signal, the combined modality would give a precise registration of the two images; the combination of MEG with high-field MRI can produce registration errors as large as 5 mm. The use of multiple sensors for ULF MRI increases both the SNR and the field of view. Chapter 6 describes another potentially far-reaching application of ULF MRI, namely neuronal current imaging (NCI) of the brain. Currently available neuronal imaging techniques include MEG, which is fast but has relatively poor spatial resolution, perhaps 10 mm, and functional MRI (fMRI) which has a millimeter resolution but is slow, on the order of seconds, and furthermore does not directly measure neuronal signals. NCI combines the ability of direct measurement of MEG with the spatial precision of MRI. In essence, the magnetic fields generated by neural currents shift the frequency of the magnetic resonance signal at a location that is imaged by the three-dimensional magnetic field gradients that form the basis of MRI. The currently achieved sensitivity of NCI is not quite sufficient to realize its goal, but it is close. The realization of NCI would represent a revolution in functional brain imaging. Improved techniques for immunoassay are always being sought, and chapter 7 introduces an entirely new topic, magnetic nanoparticles for immunoassay. These particles are bio-funtionalized, for example with a specific antibody which binds to its corresponding antigen, if it is present. Any resulting changes in the properties of the nanoparticles are detected with a SQUID. For liquid-phase detection, there are three basic methods: AC susceptibility, magnetic relaxation and remanence measurement. These methods, which have been successfully implemented for both in vivo and ex vivo applications, are highly sensitive and, although further development is required, it appears highly likely that at least some of them will be commercialized. Chapter 8 concludes the roadmap with an assessment of the commercial market for MEG systems. Despite the huge advances that have been realized since MEG was first introduced, the number of commercial systems deployed around the world remains small, around 250 units employing about 50 000 SQUIDs. The slow adoption of this technology is undoubtedly in part due to the high cost, not least because of the need to surround the entire system in an expensive magnetically shielded room. Nonetheless, the recent introduction of automatically refilling liquid-helium systems, the ongoing reduction in sensor noise, the potential availability of high-T c SQUID systems, the availability of new and better software and the combination of MEG with ULF MRI all have the potential to increase the market size in the not-so-distant future. In particular, there is a great and growing need for better noninvasive technologies to measure brain function. There are hundreds of millions of people in the world who suffer from brain disorders such as epilepsy, stroke, dementia or depression. The enormous cost to society of these diseases can be reduced by earlier and more accurate detection and diagnosis. Once the challenges outlined in this roadmap have been met and the outstanding problems have been solved, the potential demand for SQUID-based health technology can be expected to increase by ten- if not hundred-fold.

Geodesy and gravity experiment in earth orbit using a superconducting gravity gradiometer

NASA Technical Reports Server (NTRS)

Paik, H. J.

1985-01-01

A superconducting gravity gradiometer is under development with NASA support for space application. It is planned that a sensitive three-axis gravity gradiometer will be flown in a low-altitude (about 160 km) polar orbit in the 1990's for the purpose of obtaining a high-resolution gravity map of the earth. The large twice-an-orbit term in the harmonic expansion of gravity coming from the oblateness of the earth can be analyzed to obtain a precision test of the inverse square law at a distance of 100-1000 km. In this paper, the design, operating principle, and performance of the superconducting gravity gradiometer are described. The concept of a gravity-gradiometer mission (GGM), which is in an initial stage of development is discussed. In particular, requirements that such a mission imposes on the design of the cryogenic spacecraft will be addressed.

A Josephson radiation comb generator.

PubMed

Solinas, P; Gasparinetti, S; Golubev, D; Giazotto, F

2015-07-20

We propose the implementation of a Josephson Radiation Comb Generator (JRCG) based on a dc superconducting quantum interference device (SQUID) driven by an external magnetic field. When the magnetic flux crosses a diffraction node of the critical current interference pattern, the superconducting phase undergoes a jump of π and a voltage pulse is generated at the extremes of the SQUID. Under periodic drive this allows one to generate a sequence of sharp, evenly spaced voltage pulses. In the frequency domain, this corresponds to a comb-like structure similar to the one exploited in optics and metrology. With this device it is possible to generate up to several hundreds of harmonics of the driving frequency. For example, a chain of 50 identical high-critical-temperature SQUIDs driven at 1 GHz can deliver up to a 0.5 nW at 200 GHz. The availability of a fully solid-state radiation comb generator such as the JRCG, easily integrable on chip, may pave the way to a number of technological applications, from metrology to sub-millimeter wave generation.

Scanning SQUID microscope with an in-situ magnetization/demagnetization field for geological samples

NASA Astrophysics Data System (ADS)

Du, Junwei; Liu, Xiaohong; Qin, Huafeng; Wei, Zhao; Kong, Xiangyang; Liu, Qingsong; Song, Tao

2018-04-01

Magnetic properties of rocks are crucial for paleo-, rock-, environmental-magnetism, and magnetic material sciences. Conventional rock magnetometers deal with bulk properties of samples, whereas scanning microscope can map the distribution of remanent magnetization. In this study, a new scanning microscope based on a low-temperature DC superconducting quantum interference device (SQUID) equipped with an in-situ magnetization/demagnetization device was developed. To realize the combination of sensitive instrument as SQUID with high magnetizing/demagnetizing fields, the pick-up coil, the magnetization/demagnetization coils and the measurement mode of the system were optimized. The new microscope has a field sensitivity of 250 pT/√Hz at a coil-to-sample spacing of ∼350 μm, and high magnetization (0-1 T)/ demagnetization (0-300 mT, 400 Hz) functions. With this microscope, isothermal remanent magnetization (IRM) acquisition and the according alternating field (AF) demagnetization curves can be obtained for each point without transferring samples between different procedures, which could result in position deviation, waste of time, and other interferences. The newly-designed SQUID microscope, thus, can be used to investigate the rock magnetic properties of samples at a micro-area scale, and has a great potential to be an efficient tool in paleomagnetism, rock magnetism, and magnetic material studies.

TEM measurement in a low resistivity overburden performed by using low temperature SQUID

NASA Astrophysics Data System (ADS)

Ji, Yanju; Du, Shangyu; Xie, Lijun; Chang, Kai; Liu, Yang; Zhang, Yi; Xie, Xiaoming; Wang, Yuan; Lin, Jun; Rong, Liangliang

2016-12-01

Exploration of areas with thick low resistivity overburden is still a challenge for time domain transient electromagnetic method (TEM). We report modeling of a sandwich-layered earth by simulating the B field response with different conductive target layer thicknesses, thus obtaining a relationship between the resolution of the B field and the exploration depth. A low temperature Superconducting Quantum Interference Device (SQUID) is an ideal sensor for measuring the secondary magnetic field B in TEM measurements, because its sensitivity of several fT/√Hz is independent of frequency. In our TEM experiments, we utilized two different coils as receivers, a simple SQUID system, and a large transmitter loop of 200 × 200 m2 to compare the detected decay curves. At some measurement points, a decay signal of more than 300 ms duration was obtained by using the SQUID. Apparent resistivity profiles of about 9 km length are presented.

Intermodulation in nonlinear SQUID metamaterials: Experiment and theory

NASA Astrophysics Data System (ADS)

Zhang, Daimeng; Trepanier, Melissa; Antonsen, Thomas; Ott, Edward; Anlage, Steven M.

2016-11-01

The response of nonlinear metamaterials and superconducting electronics to two-tone excitation is critical for understanding their use as low-noise amplifiers and tunable filters. A new setting for such studies is that of metamaterials made of radio frequency superconducting quantum interference devices (rf-SQUIDs). The two-tone response of self-resonant rf-SQUID meta-atoms and metamaterials is studied here via intermodulation (IM) measurement over a broad range of tone frequencies and tone powers. A sharp onset followed by a surprising strongly suppressed IM region near the resonance is observed. Using a two time scale analysis technique, we present an analytical theory that successfully explains our experimental observations. The theory predicts that the IM can be manipulated with tone power, center frequency, frequency difference between the two tones, and temperature. This quantitative understanding potentially allows for the design of rf-SQUID metamaterials with either very low or very high IM response.

SQUID amplifiers for axion search experiments

NASA Astrophysics Data System (ADS)

Matlashov, Andrei; Schmelz, Matthias; Zakosarenko, Vyacheslav; Stolz, Ronny; Semertzidis, Yannis K.

2018-04-01

In the experiments for dark-matter QCD-axion searches, very weak microwave signals from a low-temperature High-Q resonant cavity should be detected using the highest sensitivity. The best commercial low-noise cryogenic semiconductor amplifiers based on high electron mobility transistors have a lowest noise temperature above 1.0 K, even if they are cooled well below 1 K. Superconducting quantum interference devices can work as microwave amplifiers with temperature noise close to the standard quantum limit. Previous SQUID-based RF amplifiers designed for axion search experiments have a microstrip resonant input coil and are thus called micro-strip SQUID amplifiers or MSAs. Due to the resonant input coupling they usually have narrow bandwidth. In this paper we report on a SQUID-based wideband microwave amplifier fabricated using sub-micron size Josephson junctions with very low capacitance. A single amplifier can be used in a frequency range of approximately 1-5 GHz.

Source localization of brain activity using helium-free interferometer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dammers, Jürgen, E-mail: J.Dammers@fz-juelich.de; Chocholacs, Harald; Eich, Eberhard

2014-05-26

To detect extremely small magnetic fields generated by the human brain, currently all commercial magnetoencephalography (MEG) systems are equipped with low-temperature (low-T{sub c}) superconducting quantum interference device (SQUID) sensors that use liquid helium for cooling. The limited and increasingly expensive supply of helium, which has seen dramatic price increases recently, has become a real problem for such systems and the situation shows no signs of abating. MEG research in the long run is now endangered. In this study, we report a MEG source localization utilizing a single, highly sensitive SQUID cooled with liquid nitrogen only. Our findings confirm that localizationmore » of neuromagnetic activity is indeed possible using high-T{sub c} SQUIDs. We believe that our findings secure the future of this exquisitely sensitive technique and have major implications for brain research and the developments of cost-effective multi-channel, high-T{sub c} SQUID-based MEG systems.« less

On estimating gravity anomalies from gradiometer data. [by numerical analysis

NASA Technical Reports Server (NTRS)

Argentiero, P.; Garza-Robles, R.

1976-01-01

The Gravsat-gradiometer mission involves flying a gradiometer on a gravity satellite (Gravsat) which is in a low, polar, and circular orbit. Results are presented of a numerical simulation of the mission which demonstrates that, if the satellite is in a 250-km orbit, 3- and 5-degree gravity anomalies may be estimated with accuracies of 0.03 and 0.01 mm/square second (3 and 1 mgal), respectively. At an altitude of 350 km, the results are 0.07 and 0.025 mm.square second (7 and 2.5 mgal), respectively. These results assume a rotating type gradiometer with a 0.1 -etvos unit accuracy. The results can readily be scaled to reflect another accuracy level.

Geopotential Error Analysis from Satellite Gradiometer and Global Positioning System Observables on Parallel Architecture

NASA Technical Reports Server (NTRS)

Schutz, Bob E.; Baker, Gregory A.

1997-01-01

The recovery of a high resolution geopotential from satellite gradiometer observations motivates the examination of high performance computational techniques. The primary subject matter addresses specifically the use of satellite gradiometer and GPS observations to form and invert the normal matrix associated with a large degree and order geopotential solution. Memory resident and out-of-core parallel linear algebra techniques along with data parallel batch algorithms form the foundation of the least squares application structure. A secondary topic includes the adoption of object oriented programming techniques to enhance modularity and reusability of code. Applications implementing the parallel and object oriented methods successfully calculate the degree variance for a degree and order 110 geopotential solution on 32 processors of the Cray T3E. The memory resident gradiometer application exhibits an overall application performance of 5.4 Gflops, and the out-of-core linear solver exhibits an overall performance of 2.4 Gflops. The combination solution derived from a sun synchronous gradiometer orbit produce average geoid height variances of 17 millimeters.

Satellite borne gravity gradiometer study

NASA Technical Reports Server (NTRS)

Metzger, E.; Jircitano, A.; Affleck, C.

1976-01-01

Gravity gradiometry is recognized to be a very difficult instrumentation problem because extremely small differential acceleration levels have to be measured, 0.1 EU corresponds to an acceleration of 10 to the minus 11th power g at two points 1 meter apart. A feasibility model of a gravity gradiometer is being developed for airborne applications using four modified versions of the proven Model VII accelerometers mounted on a slowly rotating fixture. Gravity gradients are being measured to 1.07 EU in a vertical rotation axis orientation. Equally significant are the outstanding operational characteristics such as fast reaction time, low temperature coefficients and high degree of bias stability over long periods of time. The rotating accelerometer gravity gradiometer approach and its present status is discussed and it is the foundation for the orbital gravity gradiometer analyzed. The performance levels achieved in a 1 g environment of the earth and under relatively high seismic disturbances, lend the orbital gravity gradiometer a high confidence level of success.

Geopotential error analysis from satellite gradiometer and global positioning system observables on parallel architectures

NASA Astrophysics Data System (ADS)

Baker, Gregory Allen

The recovery of a high resolution geopotential from satellite gradiometer observations motivates the examination of high performance computational techniques. The primary subject matter addresses specifically the use of satellite gradiometer and GPS observations to form and invert the normal matrix associated with a large degree and order geopotential solution. Memory resident and out-of-core parallel linear algebra techniques along with data parallel batch algorithms form the foundation of the least squares application structure. A secondary topic includes the adoption of object oriented programming techniques to enhance modularity and reusability of code. Applications implementing the parallel and object oriented methods successfully calculate the degree variance for a degree and order 110 geopotential solution on 32 processors of the Cray T3E. The memory resident gradiometer application exhibits an overall application performance of 5.4 Gflops, and the out-of-core linear solver exhibits an overall performance of 2.4 Gflops. The combination solution derived from a sun synchronous gradiometer orbit produce average geoid height variances of 17 millimeters.

White noise of Nb-based microwave superconducting quantum interference device multiplexers with NbN coplanar resonators for readout of transition edge sensors

NASA Astrophysics Data System (ADS)

Kohjiro, Satoshi; Hirayama, Fuminori; Yamamori, Hirotake; Nagasawa, Shuichi; Fukuda, Daiji; Hidaka, Mutsuo

2014-06-01

White noise of dissipationless microwave radio frequency superconducting quantum interference device (RF-SQUID) multiplexers has been experimentally studied to evaluate their readout performance for transition edge sensor (TES) photon counters ranging from near infrared to gamma ray. The characterization has been carried out at 4 K, first to avoid the low-frequency fluctuations present at around 0.1 K, and second, for a feasibility study of readout operation at 4 K for extended applications. To increase the resonant Q at 4 K and maintain low noise SQUID operation, multiplexer chips consisting of niobium nitride (NbN)-based coplanar-waveguide resonators and niobium (Nb)-based RF-SQUIDs have been developed. This hybrid multiplexer exhibited 1 × 104 ≤ Q ≤ 2 × 104 and the square root of spectral density of current noise referred to the SQUID input √SI = 31 pA/√Hz. The former and the latter are factor-of-five and seven improvements from our previous results on Nb-based resonators, respectively. Two-directional readout on the complex plane of the transmission component of scattering matrix S21 enables us to distinguish the flux noise from noise originating from other sources, such as the cryogenic high electron mobility transistor (HEMT) amplifier. Systematic noise measurements with various microwave readout powers PMR make it possible to distinguish the contribution of noise sources within the system as follows: (1) The achieved √SI is dominated by the Nyquist noise from a resistor at 4 K in parallel to the SQUID input coil which is present to prevent microwave leakage to the TES. (2) The next dominant source is either the HEMT-amplifier noise (for small values of PMR) or the quantization noise due to the resolution of 300-K electronics (for large values of PMR). By a decrease of these noise levels to a degree that is achievable by current technology, we predict that the microwave RF-SQUID multiplexer can exhibit √SI ≤ 5 pA/√Hz, i.e., close to √SI of state-of-the-art DC-SQUID-based multiplexers.

Hunting Sea Mines with UUV-Based Magnetic and Electro-Optic Sensors

DTIC Science & Technology

2010-06-01

assembly of four 3-axis fluxgate magnetometers and (c) magnetometer package for underwater deployment in flooded body section. data are automatically...features the Real-time Tracking Gradiometer (RTG), which is a multi-channel tensor gradiometer using conventional fluxgate technology. Also in this...integrated together into a Bluefin12 AUV [5]. A. RTG Sensor Technology The RTG is a multi-channel tensor gradiometer using conventional fluxgate

An EM System with Dynamic Multi-Axis Transmitter and Tensor Gradiometer Receiver

DTIC Science & Technology

2011-06-01

main difference between the spatial behavior of target anomalies measured with a magnetometer and those we measured with an EM system is in the nature...environmental and UXO applications, current efforts include the development of tensor magnetic gradiometers based on triaxial fluxgate technology by the USGS...Superconducting gradiometer/ Magnetometer Arrays and a Novel Signal Processing Technique. IEEE Trans. on Magnetics, MAG-11(2), 701-707. EM Tensor

Standardized UXO Technology Demonstration Site Blind Grid Scoring Record Number 891

DTIC Science & Technology

2008-08-01

magnetometers (Foerster CON650 gradiometers) and RTK-DGPS georeferencing will be used. The spacing between the individual fluxgate sensors will be 25 cm...used for data acquisition usually ranges from 8 to 32. b. For the demonstration at Aberdeen Proving Ground, a system with eight fluxgate ...up to 32 fluxgate gradiometers (for the APG demonstration: eight fluxgate gradiometers), a robust, all-terrain trailer, the MonMX data acquisition

Study on signal intensity of low field nuclear magnetic resonance via an indirect coupling measurement

NASA Astrophysics Data System (ADS)

Jiang, Feng-Ying; Wang, Ning; Jin, Yi-Rong; Deng, Hui; Tian, Ye; Lang, Pei-Lin; Li, Jie; Chen, Ying-Fei; Zheng, Dong-Ning

2013-04-01

We carry out an ultra-low-field nuclear magnetic resonance (NMR) experiment based on high-Tc superconducting quantum interference devices (SQUIDs). The measurement field is in a micro-tesla range (~10 μT-100 μT) and the experiment is conducted in a home-made magnetically-shielded-room (MSR). The measurements are performed by the indirect coupling method in which the signal of nuclei precession is indirectly coupled to the SQUID through a tuned copper coil transformer. In such an arrangement, the interferences of applied measurement and polarization field to the SQUID sensor are avoided and the performance of the SQUID is not destroyed. In order to compare the detection sensitivity obtained by using the SQUID with that achieved using a conventional low-noise-amplifier, we perform the measurements using a commercial room temperature amplifier. The results show that in a wide frequency range (~1 kHz-10 kHz) the measurements with the SQUID sensor exhibit a higher signal-to-noise ratio. Further, we discuss the dependence of NMR peak magnitude on measurement frequency. We attribute the reduction of the peak magnitude at high frequency to the increased field inhomogeneity as the measurement field increases. This is verified by compensating the field gradient using three sets of gradient coils.

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.

High-resolution imaging of magnetic fields using scanning superconducting quantum interference device (SQUID) microscopy

NASA Astrophysics Data System (ADS)

Fong de Los Santos, Luis E.

Development of a scanning superconducting quantum interference device (SQUID) microscope system with interchangeable sensor configurations for imaging magnetic fields of room-temperature (RT) samples with sub-millimeter resolution. The low-critical-temperature (Tc) niobium-based monolithic SQUID sensor is mounted in the tip of a sapphire rod and thermally anchored to the cryostat helium reservoir. A 25 mum sapphire window separates the vacuum space from the RT sample. A positioning mechanism allows adjusting the sample-to-sensor spacing from the top of the Dewar. I have achieved a sensor-to-sample spacing of 100 mum, which could be maintained for periods of up to 4 weeks. Different SQUID sensor configurations are necessary to achieve the best combination of spatial resolution and field sensitivity for a given magnetic source. For imaging thin sections of geological samples, I used a custom-designed monolithic low-Tc niobium bare SQUID sensor, with an effective diameter of 80 mum, and achieved a field sensitivity of 1.5 pT/Hz1/2 and a magnetic moment sensitivity of 5.4 x 10-18 Am2/Hz1/2 at a sensor-to-sample spacing of 100 mum in the white noise region for frequencies above 100 Hz. Imaging action currents in cardiac tissue requires higher field sensitivity, which can only be achieved by compromising spatial resolution. I developed a monolithic low-Tc niobium multiloop SQUID sensor, with sensor sizes ranging from 250 mum to 1 mm, and achieved sensitivities of 480 - 180 fT/Hz1/2 in the white noise region for frequencies above 100 Hz, respectively. For all sensor configurations, the spatial resolution was comparable to the effective diameter and limited by the sensor-to-sample spacing. Spatial registration allowed us to compare high-resolution images of magnetic fields associated with action currents and optical recordings of transmembrane potentials to study the bidomain nature of cardiac tissue or to match petrography to magnetic field maps in thin sections of geological samples.

Proximity-Induced Superconductivity and Quantum Interference in Topological Crystalline Insulator SnTe Thin-Film Devices.

PubMed

Klett, Robin; Schönle, Joachim; Becker, Andreas; Dyck, Denis; Borisov, Kiril; Rott, Karsten; Ramermann, Daniela; Büker, Björn; Haskenhoff, Jan; Krieft, Jan; Hübner, Torsten; Reimer, Oliver; Shekhar, Chandra; Schmalhorst, Jan-Michael; Hütten, Andreas; Felser, Claudia; Wernsdorfer, Wolfgang; Reiss, Günter

2018-02-14

Topological crystalline insulators represent a new state of matter, in which the electronic transport is governed by mirror-symmetry protected Dirac surface states. Due to the helical spin-polarization of these surface states, the proximity of topological crystalline matter to a nearby superconductor is predicted to induce unconventional superconductivity and, thus, to host Majorana physics. We report on the preparation and characterization of Nb-based superconducting quantum interference devices patterned on top of topological crystalline insulator SnTe thin films. The SnTe films show weak anti-localization, and the weak links of the superconducting quantum interference devices (SQUID) exhibit fully gapped proximity-induced superconductivity. Both properties give a coinciding coherence length of 120 nm. The SQUID oscillations induced by a magnetic field show 2π periodicity, possibly dominated by the bulk conductivity.

Multichannel System Based on a High Sensitivity Superconductive Sensor for Magnetoencephalography

PubMed Central

Rombetto, Sara; Granata, Carmine; Vettoliere, Antonio; Russo, Maurizio

2014-01-01

We developed a multichannel system based on superconducting quantum interference devices (SQUIDs) for magnetoencephalography measurements. Our system consists of 163 fully-integrated SQUID magnetometers, 154 channels and 9 references, and all of the operations are performed inside a magnetically-shielded room. The system exhibits a magnetic field noise spectral density of approximatively 5 fT/Hz1/2. The presented magnetoencephalography is the first system working in a clinical environment in Italy. PMID:25006995

Active cooling of an audio-frequency electrical resonator to microkelvin temperatures

NASA Astrophysics Data System (ADS)

Vinante, A.; Bonaldi, M.; Mezzena, R.; Falferi, P.

2010-11-01

We have cooled a macroscopic LC electrical resonator using feedback-cooling combined with an ultrasensitive dc Superconducting Quantum Interference Device (SQUID) current amplifier. The resonator, with resonance frequency of 11.5 kHz and bath temperature of 135 mK, is operated in the high coupling limit so that the SQUID back-action noise overcomes the intrinsic resonator thermal noise. The effect of correlations between the amplifier noise sources clearly show up in the experimental data, as well as the interplay of the amplifier noise with the resonator thermal noise. The lowest temperature achieved by feedback is 14 μK, corresponding to 26 resonator photons, and approaches the limit imposed by the noise energy of the SQUID amplifier.

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.

SiGe Integrated Circuit Developments for SQUID/TES Readout

NASA Astrophysics Data System (ADS)

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

2018-03-01

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

Construction of an Overhauser magnetic gradiometer and the applications in geomagnetic observation and ferromagnetic target localization

NASA Astrophysics Data System (ADS)

Liu, H.; Dong, H.; Liu, Z.; Ge, J.; Bai, B.; Zhang, C.

2017-10-01

The proton precession magnetometer with single sensor is commonly used in geomagnetic observation and magnetic anomaly detection. Due to technological limitations, the measurement accuracy is restricted by several factors such as the sensor performance, frequency measurement precision, instability of polarization module, etc. Aimed to improve the anti-interference ability, an Overhauser magnetic gradiometer with dual sensor structure was designed. An alternative design of a geomagnetic sensor with differential dual-coil structure was presented. A multi-channel frequency measurement algorithm was proposed to increase the measurement accuracy. A silicon oscillator was adopted to resolve the instability of polarization system. This paper briefly discusses the design and development of the gradiometer and compares the data recorded by this instrument with a commonly used commercially Overhauser magnetometer in the world market. The proposed gradiometer records the earth magnetic field in 24 hours with measurement accuracy of ± 0.3 nT and a sampling rate of 3 seconds per sample. The quality of data recorded is excellent and consistent with the commercial instrument. In addition, experiments of ferromagnetic target localization were conducted. This gradiometer shows a strong ability in magnetic anomaly detection and localization. To sum up, it has the advantages of convenient operation, high precision, strong anti-interference, etc., which proves the effectiveness of the dual sensor structure Overhauser magnetic gradiometer.

A spaceborne superconducting gravity gradiometer for mapping the earth's gravity field

NASA Technical Reports Server (NTRS)

Paik, H. J.

1981-01-01

The principles of a satellite gravity gradiometer system which measures all five independent components of the gravity gradient tensor with a sensitivity of 0.001 E/Hz to the 1/2 power or better, are analyzed, and the status of development of the system is reviewed. The superconducting gravity gradiometer uses sensitive superconducting accelerometers, each of which are composed of a weakly suspended superconducting proof mass, a superconducting magnetic transducer, and a low-noise superconducting magnetometer. The magnetic field produced by the transducer coils is modulated by the motion of the proof mass and detected by the magnetometer. A combination of two or four of such accelerometers with proper relative orientation of sensitive axes results in an in-line or a cross component gravity gradiometer.

SQUIDs vs. Induction Coils for Ultra-Low Field Nuclear Magnetic Resonance: Experimental and Simulation Comparison

PubMed Central

Matlashov, Andrei N.; Schultz, Larry J.; Espy, Michelle A.; Kraus, Robert H.; Savukov, Igor M.; Volegov, Petr L.; Wurden, Caroline J.

2011-01-01

Nuclear magnetic resonance (NMR) is widely used in medicine, chemistry and industry. One application area is magnetic resonance imaging (MRI). Recently it has become possible to perform NMR and MRI in the ultra-low field (ULF) regime requiring measurement field strengths of the order of only 1 Gauss. This technique exploits the advantages offered by superconducting quantum interference devices or SQUIDs. Our group has built SQUID based MRI systems for brain imaging and for liquid explosives detection at airport security checkpoints. The requirement for liquid helium cooling limits potential applications of ULF MRI for liquid identification and security purposes. Our experimental comparative investigation shows that room temperature inductive magnetometers may provide enough sensitivity in the 3–10 kHz range and can be used for fast liquid explosives detection based on ULF NMR technique. We describe experimental and computer-simulation results comparing multichannel SQUID based and induction coils based instruments that are capable of performing ULF MRI for liquid identification. PMID:21747638

Design, fabrication and characterization of a 64 pixel metallic magnetic calorimeter array with integrated, on-chip microwave SQUID multiplexer

NASA Astrophysics Data System (ADS)

Kempf, S.; Wegner, M.; Deeg, L.; Fleischmann, A.; Gastaldo, L.; Herrmann, F.; Richter, D.; Enss, C.

2017-06-01

We report on the design, fabrication and characterization of a 64 pixel metallic magnetic calorimeter array that is read out by an integrated, on-chip microwave SQUID multiplexer. Based on the results of our comprehensive device characterization we refined the state-of-the-art multiplexer model which assumes each associated non-hysteretic rf-SQUID to purely behave as a flux-dependent inductor. In particular, we include the capacitance and the subgap resistance of the Josephson junction as well as screening effects and parasitic mutual couplings between different coils that show up only when a superconducting flux transformer is attached to the SQUID input. Thanks to these modifications, we are able to explain the occurrence of a magnetic flux dependence of the internal quality factor of the microwave resonators as well as to accurately calculate the characteristic multiplexer parameters. When combining the refined multiplexer model with the thermodynamical description of a metallic magnetic calorimeter, we find a reasonable agreement between our measurements and predictions.

Microwave photon generation in a doubly tunable superconducting resonator

NASA Astrophysics Data System (ADS)

Svensson, I.-M.; Pierre, M.; Simoen, M.; Wustmann, W.; Krantz, P.; Bengtsson, A.; Johansson, G.; Bylander, J.; Shumeiko, V.; Delsing, P.

2018-03-01

We have created a doubly tunable resonator, with the intention to simulate relativistic motion of the resonator boundaries in real space. Our device is a superconducting coplanar-waveguide microwave resonator, with fundamental resonant frequency ω 1 /(2π) ~ 5 GHz. Both of its ends are terminated to ground via dc-SQUIDs, which serve as magnetic-flux-controlled inductances. Applying a flux to either SQUID allows the tuning of ω 1 /(2π) by approximately 700 MHz. Using two separate on-chip magnetic-flux lines, we modulate the SQUIDs with two tones of equal frequency, close to 2ω 1. We observe photon generation, at ω 1, above a certain pump amplitude threshold. By varying the relative phase of the two pumps we are able to control this threshold, in good agreement with a theoretical model. At the same time, some of our observations deviate from the theoretical predictions, which we attribute to parasitic couplings resulting in current driving of the SQUIDs.

Sensors and detectors based on superconducting devices. (Latest citations from the Aerospace database). Published Search

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1993-09-01

The bibliography contains citations concerning gradiometers, magnetometers, and infrared detectors which use superconductors to improve sensitivity. Applications include biomagnetic measurements for medical studies, gravity wave experiments, geomagnetism and ocean bottom magnetic exploration, galvanometers and voltmeters, astronomical telescopes, and bolometers and radiometers. Some articles refer to design considerations for cooling systems for the sensors and detectors. (Contains a minimum of 97 citations and includes a subject term index and title list.)

Sensors and detectors based on superconducting devices. January 1980-December 1991 (Citations from the NTIS Data Base). Rept. for Jan 80-Dec 91

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1991-11-01

The bibliography contains citations concerning gradiometers, magnetometers, and infrared detectors which use superconductors to improve sensitivity. Applications include biomagnetic measurements for medical studies, gravity wave experiments, geomagnetism and ocean bottom magnetic exploration. Also covered are galvanometers and voltameters, bolometers, and radiometers. References to design considerations for cooling systems for the sensors and detectors are included. (Contains 73 citations with title list and subject index.)

Note: Unshielded bilateral magnetoencephalography system using two-dimensional gradiometers

NASA Astrophysics Data System (ADS)

Seki, Yusuke; Kandori, Akihiko; Ogata, Kuniomi; Miyashita, Tsuyoshi; Kumagai, Yukio; Ohnuma, Mitsuru; Konaka, Kuni; Naritomi, Hiroaki

2010-09-01

Magnetoencephalography (MEG) noninvasively measures neuronal activity with high temporal resolution. The aim of this study was to develop a new type of MEG system that can measure bilateral MEG waveforms without a magnetically shielded room, which is an obstacle to reducing both the cost and size of an MEG system. An unshielded bilateral MEG system was developed using four two-dimensional (2D) gradiometers and two symmetric cryostats. The 2D gradiometer, which is based on a low-Tc superconducting quantum interference device and wire-wound pickup coil detects a magnetic-field gradient in two orthogonal directions, or ∂/∂x(∂2Bz/∂z2), and reduces environmental magnetic-field noise by more than 50 dB. The cryostats can be symmetrically positioned in three directions: vertical, horizontal, and rotational. This makes it possible to detect bilateral neuronal activity in the cerebral cortex simultaneously. Bilateral auditory-evoked fields (AEF) of 18 elderly subjects were measured in an unshielded hospital environment using the MEG system. As a result, both the ipsilateral and the contralateral AEF component N100m, which is the magnetic counterpart of electric N100 in electroencephalography and appears about 100 ms after the onset of an auditory stimulus, were successfully detected for all the subjects. Moreover, the ipsilateral P50m and the contralateral P50m were also detected for 12 (67%) and 16 (89%) subjects, respectively. Experimental results demonstrate that the unshielded bilateral MEG system can detect MEG waveforms, which are associated with brain dysfunction such as epilepsy, Alzheimer's disease, and Down syndrome.

Tunable resonant and non-resonant interactions between a phase qubit and LC resonator

NASA Astrophysics Data System (ADS)

Allman, Michael Shane; Whittaker, Jed D.; Castellanos-Beltran, Manuel; Cicak, Katarina; da Silva, Fabio; Defeo, Michael; Lecocq, Florent; Sirois, Adam; Teufel, John; Aumentado, Jose; Simmonds, Raymond W.

2014-03-01

We use a flux-biased radio frequency superconducting quantum interference device (rf SQUID) with an embedded flux-biased direct current (dc) SQUID to generate strong resonant and non-resonant tunable interactions between a phase qubit and a lumped-element resonator. The rf-SQUID creates a tunable magnetic susceptibility between the qubit and resonator providing resonant coupling rates from zero to near the ultra-strong coupling regime. By modulating the magnetic susceptibility, non-resonant parametric coupling achieves rates > 100 MHz . Nonlinearity of the magnetic susceptibility also leads to parametric coupling at subharmonics of the qubit-resonator detuning. Controllable coupling is generically important for constructing coupled-mode systems ubiquitous in physics, useful for both, quantum information architectures and quantum simulators. This work supported by NIST and NSA grant EAO140639.

Generation of three-qubit Greenberger-Horne-Zeilinger states of superconducting qubits by using dressed states

NASA Astrophysics Data System (ADS)

Zhang, Xu; Chen, Ye-Hong; Shi, Zhi-Cheng; Shan, Wu-Jiang; Song, Jie; Xia, Yan

2017-12-01

Combining the advantages of the dressed states and superconducting quantum interference device (SQUID) qubits, we propose an efficient scheme to generate Greenberger-Horne-Zeilinger (GHZ) states for three SQUID qubits. Firstly, we elaborate how to generate GHZ states of three SQUID qubits by choosing a set of dressed states suitably. Then, we compare the scheme by using dressed states with that via the adiabatic passage. Lastly, the influence of various decoherence factors, such as cavity decay, spontaneous emission and dephasing, is analyzed numerically. All of the results show that the GHZ state can be obtained fast and with high fidelity and that the present scheme is robust against the cavity decay and spontaneous emission. In addition, our scheme is more stable against the dephasing than the adiabatic scheme.

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.

Gravity field error analysis: Applications of GPS receivers and gradiometers on low orbiting platforms

NASA Technical Reports Server (NTRS)

Schrama, E.

1990-01-01

The concept of a Global Positioning System (GPS) receiver as a tracking facility and a gradiometer as a separate instrument on a low orbiting platform offers a unique tool to map the Earth's gravitational field with unprecedented accuracies. The former technique allows determination of the spacecraft's ephemeris at any epoch to within 3 to 10 cm, the latter permits the measurement of the tensor of second order derivatives of the gravity field to within 0.01 to 0.0001 Eotvos units depending on the type of gradiometer. First, a variety of error sources in gradiometry where emphasis is placed on the rotational problem pursuing as well a static as a dynamic approach is described. Next, an analytical technique is described and applied for an error analysis of gravity field parameters from gradiometer and GPS observation types. Results are discussed for various configurations proposed on Topex/Poseidon, Gravity Probe-B, and Aristoteles, indicating that GPS only solutions may be computed up to degree and order 35, 55, and 85 respectively, whereas a combined GPS/gradiometer experiment on Aristoteles may result in an acceptable solution up to degree and order 240.

Status of the planar electrostatic gradiometer GREMLIT for airborne geodesy

NASA Astrophysics Data System (ADS)

Boulanger, D.; Foulon, B.; Lebat, V.; Bresson, A.; Christophe, B.

2016-12-01

Taking advantage of technologies, developed by ONERA for the GRACE and GOCE space missions, the GREMLIT airborne gravity gradiometer is based of a planar electrostatic gradiometer configuration. The feasibility of the instrument and of its performance was proved by realistic simulations, based on actual data and recorded environmental aircraft perturbations, with performance of about one Eötvös along the two horizontal components of the gravity gradient. In order to assess the operation of the electrostatic gradiometer on its associated stabilized platform, a one axis prototype has also been built. The next step is the realization of the stabilization platform, controlled by the common mode outputs of the instrument itself, in order to reject the perturbations induced by the airborne environment in the horizontal directions. One of the interests of the GREMLIT instrument is the possibility of an easy hybrid configuration with a vertical one axis Cold Atoms Interferometer gravity gradiometer called GIBON and also under development at ONERA. In such hybrid instrument, The CAI instrument takes also advantage of the platform stabilized by the electrostatic one. The poster will emphasize the status of realization of the instrument and of its stabilized platform.

Fabrication of high T(sub c) superconductor thin film devices: Center director's discretionary fund

NASA Technical Reports Server (NTRS)

Sisk, R. C.

1992-01-01

This report describes a technique for fabricating superconducting weak link devices with micron-sized geometries etched in laser ablated Y1Ba2Cu3O(x) (YBCO) thin films. Careful placement of the weak link over naturally occurring grain boundaries exhibited in some YBCO thin films produces Superconducting Quantum Interference Devices (SQUID's) operating at 77 K.

Tunable Superconducting Gravity Gradiometer for Mars Climate, Atmosphere, and Gravity Field Investigation

NASA Technical Reports Server (NTRS)

Griggs, C. E.; Paik, H. J.; Moody, M. V.; Han, S.-C.; Rowlands, D. D.; Lemoine, F. G.; Shirron, P. J.

2015-01-01

We are developing a compact tensor superconducting gravity gradiometer (SGG) for obtaining gravimetric measurements from planetary orbits. A new and innovative design gives a potential sensitivity of approximately 10(sup -4) E Hz(sup - 1/2)( 1 E = 10(sup -9 S(sup -2) in the measurement band up to 0.1 Hz (suitale for short wavelength static gravity) and of approximately 10(sup -4) E Hz(sup - 1/2) in the frequency band less than 1 mHz (for long wavelength time-variable gravity) from the same device with a baseline just over 10 cm. The measurement band and sensitiy can be optimally tuned in-flight during the mission by changing resonance frequencies, which allows meaurements of both static and time-variable gravity fields from the same mission. Significant advances in the technologies needed for space-based cryogenic instruments have been made in the last decade. In particular, the use of cryocoolers will alleviate the previously severe constraint on mission lifetime imposed by the use of liquid helium, enabling mission durations in the 5 - 10 year range.

Exploring the Moon and Mars Using an Orbiting Superconducting Gravity Gradiometer

NASA Technical Reports Server (NTRS)

Paik, Ho Jung; Strayer, Donald M.

2004-01-01

Gravity measurement is fundamental to understanding the interior structure, dynamics, and evolution of planets. High-resolution gravity maps will also help locating natural resources, including subsurface water, and underground cavities for astronaut habitation on the Moon and Mars. Detecting the second spatial derivative of the potential, a gravity gradiometer mission tends to give the highest spatial resolution and has the advantage of requiring only a single satellite. We discuss gravity missions to the Moon and Mars using an orbiting Superconducting Gravity Gradiometer and discuss the instrument and spacecraft control requirements.

Towards a space-borne quantum gravity gradiometer: progress in laboratory demonstration

NASA Technical Reports Server (NTRS)

Yu, Nan; Kohel, James M.; Kellogg, James R.; Maleki, Lute

2005-01-01

This paper describes the working principles and technical benefits of atom-wave interferometer-based inertial sensors, and gives a progress report on the development of a quantum gravity gradiometer for space applications at JPL.

Magnetocardiography with sensors based on giant magnetoresistance

NASA Astrophysics Data System (ADS)

Pannetier-Lecoeur, M.; Parkkonen, L.; Sergeeva-Chollet, N.; Polovy, H.; Fermon, C.; Fowley, C.

2011-04-01

Biomagnetic signals, mostly due to the electrical activity in the body, are very weak and they can only be detected by the most sensitive magnetometers, such as Superconducting Quantum Interference Devices (SQUIDs). We report here biomagnetic recordings with hybrid sensors based on Giant MagnetoResistance (GMR). We recorded magnetic signatures of the electric activity of the human heart (magnetocardiography) in healthy volunteers. The P-wave and QRS complex, known from the corresponding electric recordings, are clearly visible in the recordings after an averaging time of about 1 min. Multiple recordings at different locations over the chest yielded a dipolar magnetic field map and allowed localizing the underlying current sources. The sensitivity of the GMR-based sensors is now approaching that of SQUIDs and paves way for spin electronics devices for functional imaging of the body.

Characterization and demonstration results of a SQUID magnetometer system developed for geomagnetic field measurements

NASA Astrophysics Data System (ADS)

Kawai, J.; Miyamoto, M.; Kawabata, M.; Nosé, M.; Haruta, Y.; Uehara, G.

2017-08-01

We characterized a low temperature superconducting quantum interference device (SQUID) magnetometer system developed for high-sensitivity geomagnetic field measurement, and demonstrated the detection of weak geomagnetic signals. The SQUID magnetometer system is comprised of three-axis SQUID magnetometers housed in a glass fiber reinforced plastic cryostat, readout electronics with flux locked loop (FLL), a 24-bit data logger with a global positioning system and batteries. The system noise was approximately 0.2 pT √Hz- 1/2 in the 1-50 Hz frequency range. This performance was determined by including the thermal noise and the shielding effect of the copper shield, which covered the SQUID magnetometers to eliminate high-frequency interference. The temperature drift of the system was ˜0.8 pT °C- 1 in an FLL operation. The system operated for a month using 33 l liquid helium. Using this system, we performed the measurements of geomagnetic field in the open-air, far away from the city. The system could detect weak geomagnetic signals such as the Schumann resonance with sixth harmonics, and the ionospheric Alfvén resonance appearing at night, for the north-south and east-west components of the geomagnetic field. We confirm that the system was capable of high-sensitivity measurement of the weak geomagnetic activities.

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.

Biomagnetic instrumentation and measurement

NASA Technical Reports Server (NTRS)

Iufer, E. J.

1978-01-01

The instruments and techniques of biomagnetic measurement have progressed greatly in the past 15 years and are now of a quality appropriate to clinical applications. The paper reports on recent developments in the design and application of SQUID (Superconducting Quantum Interference Device) magnetometers to biomagnetic measurement. The discussion covers biomagnetic field levels, magnetocardiography, magnetic susceptibility plethysmography, ambient noise and sensor types, principles of operation of a SQUID magnetometer, and laboratory techniques. Of the many promising applications of noninvasive biomagnetic measurement, magnetocardiography is the most advanced and the most likely to find clinical application in the near future.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kirtley, John R., E-mail: jkirtley@stanford.edu; Rosenberg, Aaron J.; Palmstrom, Johanna C.

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

SQUIDs vs. Faraday coils for ultlra-low field nuclear magnetic resonance: experimental and simulation comparison

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matlashov, Andrei N; Espy, Michelle A; Kraus, Robert H

2010-01-01

Nuclear magnetic resonance (NMR) methods are widely used in medicine, chemistry and industry. One application area is magnetic resonance imaging or MRI. Recently it has become possible to perform NMR and MRI in ultra-low field (ULF) regime that requires measurement field strengths only of the order of 1 Gauss. These techniques exploit the advantages offered by superconducting quantum interference devices or SQUIDs. Our group at LANL has built SQUID based MRI systems for brain imaging and for liquid explosives detection at airports security checkpoints. The requirement for liquid helium cooling limits potential applications of ULF MRI for liquid identification andmore » security purposes. Our experimental comparative investigation shows that room temperature inductive magnetometers provide enough sensitivity in the 3-10 kHz range and can be used for fast liquid explosives detection based on ULF NMR/MRI technique. We describe an experimental and computer simulation comparison of the world's first multichannel SQUID based and Faraday coils based instruments that are capable of performing ULF MRI for liquids identification.« less

Scanning-SQUID investigation of spin-orbit torque acting on yttrium iron garnet devices

NASA Astrophysics Data System (ADS)

Rosenberg, Aaron J.; Jermain, Colin L.; Aradhya, Sriharsha V.; Brangham, Jack T.; Nowack, Katja C.; Kirtley, John R.; Yang, Fengyuan; Ralph, Daniel C.; Moler, Kathryn A.

Successful manipulation of electrically insulating magnets, such as yttrium iron garnet, by by current-driven spin-orbit torques could provide a highly efficient platform for spintronic memory. Compared to devices fabricated using magnetic metals, magnetic insulators have the advantage of the ultra-low magnetic damping and the elimination of shunting currents in the magnet that reduce the torque efficiency. Here, we apply current in the spin Hall metal β-Ta to manipulate the magnetic orientation of micron-sized, electrically-insulating yttrium iron garnet devices. We do not observe spin-torque switching even for applied currents well above the critical current expected in a macrospin switching model. This suggests either inefficient transfer of spin torque at our Ta/YIG interface or a breakdown of the macrospin approximation. This work is supported by FAME, one of six centers of STARnet sponsored by MARCO and DARPA. The SQUID microscope and sensors were developed with support from the NSF-sponsored Center NSF-NSEC 0830228, and from NSF IMR-MIP 0957616.

Spaceborne Gravity Gradiometers

NASA Technical Reports Server (NTRS)

Wells, W. C. (Editor)

1984-01-01

The current status of gravity gradiometers and technology that could be available in the 1990's for the GRAVSAT-B mission are assessed. Problems associated with sensors, testing, spacecraft, and data processing are explored as well as critical steps, schedule, and cost factors in the development plan.

White noise of Nb-based microwave superconducting quantum interference device multiplexers with NbN coplanar resonators for readout of transition edge sensors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kohjiro, Satoshi; Hirayama, Fuminori; Yamamori, Hirotake

2014-06-14

White noise of dissipationless microwave radio frequency superconducting quantum interference device (RF-SQUID) multiplexers has been experimentally studied to evaluate their readout performance for transition edge sensor (TES) photon counters ranging from near infrared to gamma ray. The characterization has been carried out at 4 K, first to avoid the low-frequency fluctuations present at around 0.1 K, and second, for a feasibility study of readout operation at 4 K for extended applications. To increase the resonant Q at 4 K and maintain low noise SQUID operation, multiplexer chips consisting of niobium nitride (NbN)-based coplanar-waveguide resonators and niobium (Nb)-based RF-SQUIDs have been developed. This hybrid multiplexermore » exhibited 1 × 10{sup 4} ≤ Q ≤ 2 × 10{sup 4} and the square root of spectral density of current noise referred to the SQUID input √S{sub I} = 31 pA/√Hz. The former and the latter are factor-of-five and seven improvements from our previous results on Nb-based resonators, respectively. Two-directional readout on the complex plane of the transmission component of scattering matrix S{sub 21} enables us to distinguish the flux noise from noise originating from other sources, such as the cryogenic high electron mobility transistor (HEMT) amplifier. Systematic noise measurements with various microwave readout powers P{sub MR} make it possible to distinguish the contribution of noise sources within the system as follows: (1) The achieved √S{sub I} is dominated by the Nyquist noise from a resistor at 4 K in parallel to the SQUID input coil which is present to prevent microwave leakage to the TES. (2) The next dominant source is either the HEMT-amplifier noise (for small values of P{sub MR}) or the quantization noise due to the resolution of 300-K electronics (for large values of P{sub MR}). By a decrease of these noise levels to a degree that is achievable by current technology, we predict that the microwave RF-SQUID multiplexer can exhibit √S{sub I} ≤ 5 pA/√Hz, i.e., close to √S{sub I} of state-of-the-art DC-SQUID-based multiplexers.« less

Extraction of remanent magnetization from magnetization vector inversions of airborne full tensor magnetic gradiometry data

NASA Astrophysics Data System (ADS)

Queitsch, M.; Schiffler, M.; Stolz, R.; Meyer, M.; Kukowski, N.

2017-12-01

Measurements of the Earth's magnetic field are one of the most used methods in geophysical exploration. The ambiguity of the method, especially during modeling and inversion of magnetic field data sets, is one of its biggest challenges. Additional directional information, e.g. gathered by gradiometer systems based on Superconducting Quantum Interference Devices (SQUIDs), will positively influence the inversion results and will thus lead to better subsurface magnetization models. This is especially beneficial, regarding the shape and direction of magnetized structures, especially when a significant remanent magnetization of the underlying sources is present. The possibility to separate induced and remanent contributions to the total magnetization may in future also open up advanced ways for geological interpretation of the data, e.g. a first estimation of diagenesis processes. In this study we present the results of airborne full tensor magnetic gradiometry (FTMG) surveys conducted over a dolerite intrusion in central Germany and the results of two magnetization vector inversions (MVI) of the FTMG and a conventional total field anomaly data set. A separation of the two main contributions of the acquired total magnetization will be compared with information of the rock magnetization measured on orientated rock samples. The FTMG inversion results show a much better agreement in direction and strength of both total and remanent magnetization compared to the inversion using only total field anomaly data. To enhance the separation process, the application of additional geophysical methods, i.e. frequency domain electromagnetics (FDEM), in order to gather spatial information of subsurface rock susceptibility will also be discussed. In this approach, we try to extract not only information on subsurface conductivity but also the induced magnetization. Using the total magnetization from the FTMG data and the induced magnetization from the FDEM data, the full separation of induced and remanent magnetization should be enabled. First results this approach will be shown and discussed.

Magnetic induction spectroscopy (MIS)-probe design for cervical tissue measurements.

PubMed

Wang, Jau-Yi; Healey, Timothy; Barker, Anthony; Brown, Brian; Monk, Chris; Anumba, Dilly

2017-05-01

Gradiometers have the advantage of increasing measuring sensitivity, which is particularly useful in magnetic induction spectroscopy (MIS) for bio-impedance measurements. Traditional gradiometers use a pair of field sensing coils equally distant and on opposite sides of a drive coil, which provides high immunity to interference. In this paper, a ferrite-cored coaxial gradiometer probe of 29 mm diameter has been developed for measuring the impedance spectra of cervical tissues in vivo. It consists of a ferrite rod with outer ferrite confinement screening in order to eliminate the signals from surrounding tissue. The magnetic screening efficiency was compared with an air-cored gradiometer probe. For both gradiometer probes, a drive coil and two sensing coils were wound on a borosilicate glass former aligned coaxially with two sensing coils equidistant from the drive coil. The signal sensitivity of those two MIS gradiometers has been measured using saline samples with a conductivity range between 0.1 and 1.1 S m -1 . Finite element methods using COMSOL Multiphysics have been used to simulate the distribution of sensitivity to conductivity over the face of each probe and with depth. The ferrite-cored probe has a sensitivity confined to the volume defined by the gap between the ferrite core and outer tube of ferrite while the air-cored probe without any magnetic shielding had a wide sensitivity over the face and the side of the probe. Four saline samples and one of distilled water with conductivities from 0.1 to 1.1 S m -1 have been used to make conductivity measurements at frequencies of 50 kHz, 100 kHz, and 300 kHz. The measurement accuracy of the air-cored MIS probe was 0.09 S m -1 at 50 kHz, improving to 0.05 S m -1 at 300 kHz. For the ferrite-cored MIS probe, the measurement accuracy was 0.28 S m -1 at 50 kHz, improving to 0.04 S m -1 at 300 kHz. In vivo measurements on human hand have been performed using both types of gradiometers and the conductivity is consistent with reported data.

SQUID-based current sensing noise thermometry for quantum resistors at dilution refrigerator temperatures

NASA Astrophysics Data System (ADS)

Kleinbaum, Ethan; Shingla, Vidhi; Csáthy, G. A.

2017-03-01

We present a dc Superconducting QUantum Interference Device (SQUID)-based current amplifier with an estimated input referred noise of only 2.3 fA/√{Hz}. Because of such a low amplifier noise, the circuit is useful for Johnson noise thermometry of quantum resistors in the kΩ range down to mK temperatures. In particular, we demonstrate that our circuit does not contribute appreciable noise to the Johnson noise of a 3.25 kΩ resistor down to 16 mK. Our circuit is a useful alternative to the commonly used High Electron Mobility Transistor-based amplifiers, but in contrast to the latter, it offers a much reduced 1/f noise. In comparison to SQUIDs interfaced with cryogenic current comparators, our circuit has similar low noise levels, but it is easier to build and to shield from magnetic pickup.

Investigation of properties of nanobridge Josephson junctions and superconducting tracks fabricated by FIB

NASA Astrophysics Data System (ADS)

Li, B.; Godfrey, T.; Cox, D.; Li, T.; Gallop, J.; Galer, S.; Nisbet, A.; Romans, Ed; Hao, L.

2018-02-01

An important requirement across a range of sensitive detectors is to determine accurately the energy deposited by the impact of a particle in a small volume. The particle may be anything from a visible photon through to an X-ray or massive charged particle. We have been developing nanobridge Josephson junctions based SQUIDs and nanoSQUID devices covering the entire range of particle detection energies from 1eV to MeV. In this paper we discuss some developments in nanobridge Josephson junctions fabrication using focussed ion beam (FIB) and how these developments impact future applications. We focus on tuning of the transition temperature of a superconducting thin-film absorber, with the aim to match the absorber Tc to the working temperature range of the SQUID and also on using a new Xe FIB to improve Josephson junction and superconducting film quality.

A 20-channel magnetoencephalography system based on optically pumped magnetometers

NASA Astrophysics Data System (ADS)

Borna, Amir; Carter, Tony R.; Goldberg, Josh D.; Colombo, Anthony P.; Jau, Yuan-Yu; Berry, Christopher; McKay, Jim; Stephen, Julia; Weisend, Michael; Schwindt, Peter D. D.

2017-12-01

We describe a multichannel magnetoencephalography (MEG) system that uses optically pumped magnetometers (OPMs) to sense the magnetic fields of the human brain. The system consists of an array of 20 OPM channels conforming to the human subject’s head, a person-sized magnetic shield containing the array and the human subject, a laser system to drive the OPM array, and various control and data acquisition systems. We conducted two MEG experiments: auditory evoked magnetic field and somatosensory evoked magnetic field, on three healthy male subjects, using both our OPM array and a 306-channel Elekta-Neuromag superconducting quantum interference device (SQUID) MEG system. The described OPM array measures the tangential components of the magnetic field as opposed to the radial component measured by most SQUID-based MEG systems. Herein, we compare the results of the OPM- and SQUID-based MEG systems on the auditory and somatosensory data recorded in the same individuals on both systems.

Quantum Gravity Gradiometer Development for Space

NASA Technical Reports Server (NTRS)

Kohel, James M.; Yu, Nan; Kellogg, James R.; Thompson, Robert J.; Aveline, David C.; Maleki, Lute

2006-01-01

Funded by the Advanced Technology Component Program, we have completed the development of a laboratory-based quantum gravity gradiometer based on atom interferometer technology. This is our first step towards a new spaceborne gradiometer instrument, which can significantly contribute to global gravity mapping and monitoring important in the understanding of the solid earth, ice and oceans, and dynamic processes. In this paper, we will briefly review the principles and technical benefits of atom-wave interferometer-based inertial sensors in space. We will then describe the technical implementation of the laboratory setup and report its status. We will also discuss our implementation plan for the next generation instrument.

Underwater magnetic gradiometer for magnetic anomaly detection, localization, and tracking

NASA Astrophysics Data System (ADS)

Kumar, S.; Sulzberger, G.; Bono, J.; Skvoretz, D.; Allen, G. I.; Clem, T. R.; Ebbert, M.; Bennett, S. L.; Ostrom, R. K.; Tzouris, A.

2007-04-01

GE Security and the Naval Surface Warfare Center, Panama City (NSWC-PC) have collaborated to develop a magnetic gradiometer, called the Real-time Tracking Gradiometer or RTG that is mounted inside an unmanned underwater vehicle (UUV). The RTG is part of a buried mine hunting platform being developed by the United States Navy. The RTG has been successfully used to make test runs on mine-like targets buried off the coast of Florida. We will present a general description of the system and latest results describing system performance. This system can be also potentially used for other applications including those in the area of Homeland Security.

Superconducting resonators as beam splitters for linear-optics quantum computation.

PubMed

Chirolli, Luca; Burkard, Guido; Kumar, Shwetank; Divincenzo, David P

2010-06-11

We propose and analyze a technique for producing a beam-splitting quantum gate between two modes of a ring-resonator superconducting cavity. The cavity has two integrated superconducting quantum interference devices (SQUIDs) that are modulated by applying an external magnetic field. The gate is accomplished by applying a radio frequency pulse to one of the SQUIDs at the difference of the two mode frequencies. Departures from perfect beam splitting only arise from corrections to the rotating wave approximation; an exact calculation gives a fidelity of >0.9992. Our construction completes the toolkit for linear-optics quantum computing in circuit quantum electrodynamics.

Applications of Josephson Junction SQUIDs (Superconducting Quantum Interference Device) and Arrays.

DTIC Science & Technology

1982-11-01

Research, Cntract 7he transient respose is doinated by o NO. 00014-61-C-0615. and Wj. Figure 2 shows the time evolution of e a:d e M for owI, 0-1 and 5...connect a dc S 0UID "Shunted Josephson Tunel Junctions- if gh transmitter with another dc SQU D receiver by a Frequency, Self -Pvmd L Nise lifiers...resistive SQUID WVO incidentally to their self -puVzed Josepson perametric2 mplifier. Using a SQJID with 6 -2. ZmpHi, r-3xlO . and a in matching

Superconducting gravity gradiometer for space and terrestrial applications

NASA Technical Reports Server (NTRS)

Moody, M. V.; Chan, H. A.; Paik, H. J.

1986-01-01

A three-axis superconducting gravity gradiometer with a potential sensitivity better than Eotvos per sq root Hz is currently under development for applications in space. Although such a high sensitivity may be needed for only a limited number of terrestrial applications, superconductivity offers many extraordinary effects which can be used to obtain a gravity gradiometer with other characteristics necessary for operation in a hostile moving-base environment. Utilizing a number of recently devised techniques which rely on certain properties of superconductors, a design for a sensitive yet rugged gravity gradiometer with a high degree of stability and a common-mode rejection ratio greater than 10 to the 9th is produced. With a base line of 0.11 m, a sensitivity of 0.1 Eotvos per sq root Hz is expected in an environment monitored to a level of 0.01 m/sq sec sq root Hz for linear vibration and 7 x 10 to the -6th rad/s sq root Hz for angular vibration. A conventional stabilized platform can be used at this level. The intrinsic noise level, which is two orders of magnitude lower, could be achieved by monitoring the attitude with a superconducting angular accelerometer which is under development. In addition, the new gradiometer design has the versatility of adapting the instrument to different gravity biases by adjusting stored dc currents.

Meissner effect measurement of single indium particle using a customized on-chip nano-scale superconducting quantum interference device system

NASA Astrophysics Data System (ADS)

Wu, Long; Chen, Lei; Wang, Hao; Liu, Xiaoyu; Wang, Zhen

2017-04-01

As many emergent phenomena of superconductivity appear on a smaller scale and at lower dimension, commercial magnetic property measurement systems (MPMSs) no longer provide the sensitivity necessary to study the Meissner effect of small superconductors. The nano-scale superconducting quantum interference device (nano-SQUID) is considered one of the most sensitive magnetic sensors for the magnetic characterization of mesoscopic or microscopic samples. Here, we develop a customized on-chip nano-SQUID measurement system based on a pulsed current biasing method. The noise performance of our system is approximately 4.6 × 10-17 emu/Hz1/2, representing an improvement of 9 orders of magnitude compared with that of a commercial MPMS (~10-8 emu/Hz1/2). Furthermore, we demonstrate the measurement of the Meissner effect of a single indium (In) particle (of 47 μm in diameter) using our on-chip nano-SQUID system. The system enables the observation of the prompt superconducting transition of the Meissner effect of a single In particle, thereby providing more accurate characterization of the critical field Hc and temperature Tc. In addition, the retrapping field Hre as a function of temperature T of single In particle shows disparate behavior from that of a large ensemble.

Quantum interference in an interfacial superconductor.

PubMed

Goswami, Srijit; Mulazimoglu, Emre; Monteiro, Ana M R V L; Wölbing, Roman; Koelle, Dieter; Kleiner, Reinhold; Blanter, Ya M; Vandersypen, Lieven M K; Caviglia, Andrea D

2016-10-01

The two-dimensional superconductor that forms at the interface between the complex oxides lanthanum aluminate (LAO) and strontium titanate (STO) has several intriguing properties that set it apart from conventional superconductors. Most notably, an electric field can be used to tune its critical temperature (T c ; ref. 7), revealing a dome-shaped phase diagram reminiscent of high-T c superconductors. So far, experiments with oxide interfaces have measured quantities that probe only the magnitude of the superconducting order parameter and are not sensitive to its phase. Here, we perform phase-sensitive measurements by realizing the first superconducting quantum interference devices (SQUIDs) at the LAO/STO interface. Furthermore, we develop a new paradigm for the creation of superconducting circuit elements, where local gates enable the in situ creation and control of Josephson junctions. These gate-defined SQUIDs are unique in that the entire device is made from a single superconductor with purely electrostatic interfaces between the superconducting reservoir and the weak link. We complement our experiments with numerical simulations and show that the low superfluid density of this interfacial superconductor results in a large, gate-controllable kinetic inductance of the SQUID. Our observation of robust quantum interference opens up a new pathway to understanding the nature of superconductivity at oxide interfaces.

Source analysis of MEG activities during sleep (abstract)

NASA Astrophysics Data System (ADS)

Ueno, S.; Iramina, K.

1991-04-01

The present study focuses on magnetic fields of the brain activities during sleep, in particular on K-complexes, vertex waves, and sleep spindles in human subjects. We analyzed these waveforms based on both topographic EEG (electroencephalographic) maps and magnetic fields measurements, called MEGs (magnetoencephalograms). The components of magnetic fields perpendicular to the surface of the head were measured using a dc SQUID magnetometer with a second derivative gradiometer. In our computer simulation, the head is assumed to be a homogeneous spherical volume conductor, with electric sources of brain activity modeled as current dipoles. Comparison of computer simulations with the measured data, particularly the MEG, suggests that the source of K-complexes can be modeled by two current dipoles. A source for the vertex wave is modeled by a single current dipole which orients along the body axis out of the head. By again measuring the simultaneous MEG and EEG signals, it is possible to uniquely determine the orientation of this dipole, particularly when it is tilted slightly off-axis. In sleep stage 2, fast waves of magnetic fields consistently appeared, but EEG spindles appeared intermittently. The results suggest that there exist sources which are undetectable by electrical measurement but are detectable by magnetic-field measurement. Such source can be described by a pair of opposing dipoles of which directions are oppositely oriented.

UXO Forum 1996

DTIC Science & Technology

1996-01-01

used to locate and characterize a magnetic dipole source, and this finding accelerated the development of superconducting tensor gradiometers for... superconducting magnetic field gradiometer, two-color infrared camera, synthetic aperture radar, and a visible spectrum camera. The combination of these...Pieter Hoekstra, Blackhawk GeoSciences ......................................... 68 Prediction for UXO Shape and Orientation Effects on Magnetic

Compatibility of photomultiplier tube operation with SQUIDs for a neutron EDM experiment

NASA Astrophysics Data System (ADS)

Libersky, Matthew; nEDM Collaboration

2013-10-01

An experiment at the Spallation Neutron Source at Oak Ridge National Laboratory with the goal of reducing the experimental limit on the electric dipole moment (EDM) of the neutron will measure the precession frequencies of neutrons when a strong electric field is applied parallel and anti-parallel to a weak magnetic field. A difference in these frequencies would indicate a nonzero neutron EDM. To correct for drifts of the magnetic field in the measurement volume, polarized 3He will be used as a co-magnetometer. In one of the two methods built into the apparatus, superconducting quantum interference devices (SQUIDs) will be used to read out the 3He magnetization. Photomultiplier tubes will be used concurrently to measure scintillation light from neutron capture by 3He. However, the simultaneous noise-sensitive magnetic field measurement by the SQUIDs makes conventional PMT operation problematic due to the alternating current involved in generating the high voltages needed. Tests were carried out at Los Alamos National Laboratory to study the compatibility of simultaneous SQUID and PMT operation, using a custom battery-powered high-voltage power supply developed by Meyer and Smith (NIM A 647.1) to operate the PMT. The results of these tests will be presented.

The front-end electronics of the LSPE-SWIPE experiment

NASA Astrophysics Data System (ADS)

Fontanelli, F.; Biasotti, M.; Bevilacqua, A.; Siccardi, F.

2016-07-01

The SWIPE detector of the Ballon Borne Mission LSPE (see e.g. the contribution of P. de Bernardis et al. in this conference) intends to measure the primordial 'B-mode' polarization of the Cosmic Microwave Background (CMB). For this scope microwave telescopes need sensitive cryogenic bolometers with an overall equivalent noise temperature in the nK range. The detector is a spiderweb bolometer based on transition edge sensor and followed by a SQUID to perform the signal readout. This contribution will concentrate on the design, description and first tests on the front-end electronics which processes the squid output (and controls it). The squid output is first amplified by a very low noise preamplifier based on a discrete JFET input differential architecture followed by a low noise CMOS operational amplifier. Equivalent input noise density is 0.6 nV/Hz and bandwidth extends up to at least 2 MHz. Both devices (JFET and CMOS amplifier) have been tested at liquid nitrogen. The second part of the contribution will discuss design and results of the control electronics, both the flux locked loop for the squid and the slow control chain to monitor and set up the system will be reviewed.

Cross-correlation limit of a SQUID-based noise thermometer of the pMFFT type

NASA Astrophysics Data System (ADS)

Kirste, A.; Engert, J.

2018-03-01

The primary magnetic field fluctuation thermometer (pMFFT) is a SQUID-based noise thermometer for temperatures below 1 K, which complies with metrological requirements. It combines two signal channels in order to apply the cross-correlation technique, but it requires statistically independent noise signals for proper operation. In order to check the limit of the cross-correlation readout, we have performed zero measurements in the millikelvin range in a setup that is identical to the pMFFT, except for the removed temperature sensor. We examined the influence of different parameters such as SQUID working point or flux-lock loop parameters on the minimum cross-correlation signal down to 24 mK and below 100 kHz. Depending on the configuration, typical minimum SQUID-referred cross-power spectral densities of 1.5 × 10‑15 Φ _0^2/Hz or even smaller values were observed. For the pMFFT, considering its thermal noise spectrum, these flux densities correspond to a device noise temperature of ≤2.5 µK, thereby ensuring a negligible uncertainty contribution at the lower end of the PLTS-2000 (0.9 mK).

SQUID sensor application for small metallic particle detection

NASA Astrophysics Data System (ADS)

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

2009-04-01

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

Gradio: Project proposal for satellite gradiometry

NASA Technical Reports Server (NTRS)

Balmino, G.; Barilier, F.; Bernard, A.; Bouzat, C.; Riviera, G.; Runavot, J.

1981-01-01

A gradiometric approach, rather than the more complicated satellite to satellite tracking, is proposed for studying anomalies in the gravitational fields of the Earth and, possibly, other telluric bodies. The first analyses of a gradiometer based on four of ONERA's CACTUS or SUPERCACTUS accelerometers are summarized. it is shown that the obstacles to achieving the required accuracy are not insuperable. The device will be carried in a 1000 kg lens shaped satellite in a heliosynchronous orbit 200 to 300 km in altitude. The first launching is planned for the end of 1987.

Microfabricated optically pumped magnetometer arrays for biomedical imaging

NASA Astrophysics Data System (ADS)

Perry, A. R.; Sheng, D.; Krzyzewski, S. P.; Geller, S.; Knappe, S.

2017-02-01

Optically-pumped magnetometers have demonstrated magnetic field measurements as precise as the best superconducting quantum interference device magnetometers. Our group develops miniature alkali atom-based magnetic sensors using microfabrication technology. Our sensors do not require cryogenic cooling, and can be positioned very close to the sample, making these sensors an attractive option for development in the medical community. We will present our latest chip-scale optically-pumped gradiometer developed for array applications to image magnetic fields from the brain noninvasively. These developments should lead to improved spatial resolution, and potentially sensitive measurements in unshielded environments.

Superconductive imaging surface magnetometer

DOEpatents

Overton, Jr., William C.; van Hulsteyn, David B.; Flynn, Edward R.

1991-01-01

An improved pick-up coil system for use with Superconducting Quantum Interference Device gradiometers and magnetometers involving the use of superconducting plates near conventional pick-up coil arrangements to provide imaging of nearby dipole sources and to deflect environmental magnetic noise away from the pick-up coils. This allows the practice of gradiometry and magnetometry in magnetically unshielded environments. One embodiment uses a hemispherically shaped superconducting plate with interior pick-up coils, allowing brain wave measurements to be made on human patients. another embodiment using flat superconducting plates could be used in non-destructive evaluation of materials.

Non-invasive and high-sensitivity scanning detection of magnetic nanoparticles in animals using high-Tc scanning superconducting-quantum-interference-device biosusceptometry.

PubMed

Chieh, J J; Hong, C Y

2011-08-01

Although magnetic nanoparticles (MNPs) have been widely applied to animals in biomedicine, MNPs within animals should be examined in real time, in vivo, and without bio-damaged possibility to evaluate whether the bio-function of MNPs is valid or to further controls the biomedicinal process because of accompanying complex problems such as MNPs distribution and MNPs biodegradation. The non-invasive and high-sensitivity scanning detection of MNPs in animals using ac susceptometry based on a high-T(c) superconducting quantum interference device (SQUID) is presented. The non-invasive results and biopsy results show good agreement, and two gold-standard biomedicine methods, Prussian blue stain and inductively coupled plasma, prove the magnetic results. This confirms that the future clinical diagnosis of bio-functional MNPs could be operated by using scanning SQUID biosusceptometry as conveniently as an ultrasonic probe.

Proceedings of an ESA-NASA Workshop on a Joint Solid Earth Program

NASA Technical Reports Server (NTRS)

Guyenne, T. Duc (Editor); Hunt, James J. (Editor)

1987-01-01

The NASA geodynamics program; spaceborne magnetometry; spaceborne gravity gradiometry (characterizing the data type); terrestrial gravity data and comparisons with satellite data; GRADIO three-axis electrostatic accelerometers; gradiometer accommodation on board a drag-free satellite; gradiometer mission spectral analysis and simulation studies; and an opto-electronic accelerometer system were discussed.

Bragg gravity-gradiometer using the 1S0–3P1 intercombination transition of 88Sr

NASA Astrophysics Data System (ADS)

del Aguila, R. P.; Mazzoni, T.; Hu, L.; Salvi, L.; Tino, G. M.; Poli, N.

2018-04-01

We present a gradiometer based on matter-wave interference of alkaline-earth-metal atoms, namely 88Sr. The coherent manipulation of the atomic external degrees of freedom is obtained by large-momentum-transfer Bragg diffraction, driven by laser fields detuned away from the narrow 1S0–3P1 intercombination transition. We use a well-controlled artificial gradient, realized by changing the relative frequencies of the Bragg pulses during the interferometer sequence, in order to characterize the sensitivity of the gradiometer. The sensitivity reaches 1.5 × 10‑5 s‑2 for an interferometer time of 20 ms, limited only by geometrical constraints. We observed extremely low sensitivity of the gradiometric phase to magnetic field gradients, approaching a value 104 times lower than the sensitivity of alkali-atom based gradiometers, limited by the interferometer sensitivity. An efficient double-launch technique employing accelerated red vertical lattices from a single magneto-optical trap cloud is also demonstrated. These results highlight strontium as an ideal candidate for precision measurements of gravity gradients, with potential application in future precision tests of fundamental physics.

Summary Report of the Summer Conference of the DARPA-Materials Research Council Held in La Jolla, California on 6-30 July 1987

DTIC Science & Technology

1987-07-01

that any array detector have very broad dynamic range. iv.) Analytical methods used in extracting structural data from experimental observations from...important influence on magnet design and on specialized magnetic devices ( SQUID devices) and forms the basis for promising electronic devices ’Josephson...printable inks using 123 powders. (2) Control of interfacial reactions between the superconductors and the dielectric. (3) Development of suitable

Superconducting inductive displacement detection of a microcantilever

NASA Astrophysics Data System (ADS)

Vinante, A.

2014-07-01

We demonstrate a superconducting inductive technique to measure the displacement of a micromechanical resonator. In our scheme, a type I superconducting microsphere is attached to the free end of a microcantilever and approached to the loop of a dc Superconducting Quantum Interference Device (SQUID) microsusceptometer. A local magnetic field as low as 100 μT, generated by a field coil concentric to the SQUID, enables detection of the cantilever thermomechanical noise at 4.2 K. The magnetomechanical coupling and the magnetic spring are in good agreement with image method calculations assuming pure Meissner effect. These measurements are relevant to recent proposals of quantum magnetomechanics experiments based on levitating superconducting microparticles.

Spin-1 models in the ultrastrong-coupling regime of circuit QED

NASA Astrophysics Data System (ADS)

Albarrán-Arriagada, F.; Lamata, L.; Solano, E.; Romero, G.; Retamal, J. C.

2018-02-01

We propose a superconducting circuit platform for simulating spin-1 models. To this purpose we consider a chain of N ultrastrongly coupled qubit-resonator systems interacting through a grounded superconducting quantum interference device (SQUID). The anharmonic spectrum of the qubit-resonator system and the selection rules imposed by the global parity symmetry allow us to activate well controlled two-body quantum gates via ac pulses applied to the SQUID. We show that our proposal has the same simulation time for any number of spin-1 interacting particles. This scheme may be implemented within the state-of-the-art circuit QED in the ultrastrong coupling regime.

High-resolution room-temperature sample scanning superconducting quantum interference device microscope configurable for geological and biomagnetic applications

NASA Astrophysics Data System (ADS)

Fong, L. E.; Holzer, J. R.; McBride, K. K.; Lima, E. A.; Baudenbacher, F.; Radparvar, M.

2005-05-01

We have developed a scanning superconducting quantum interference device (SQUID) microscope system with interchangeable sensor configurations for imaging magnetic fields of room-temperature (RT) samples with submillimeter resolution. The low-critical-temperature (Tc) niobium-based monolithic SQUID sensors are mounted on the tip of a sapphire and thermally anchored to the helium reservoir. A 25μm sapphire window separates the vacuum space from the RT sample. A positioning mechanism allows us to adjust the sample-to-sensor spacing from the top of the Dewar. We achieved a sensor-to-sample spacing of 100μm, which could be maintained for periods of up to four weeks. Different SQUID sensor designs are necessary to achieve the best combination of spatial resolution and field sensitivity for a given source configuration. For imaging thin sections of geological samples, we used a custom-designed monolithic low-Tc niobium bare SQUID sensor, with an effective diameter of 80μm, and achieved a field sensitivity of 1.5pT/Hz1/2 and a magnetic moment sensitivity of 5.4×10-18Am2/Hz1/2 at a sensor-to-sample spacing of 100μm in the white noise region for frequencies above 100Hz. Imaging action currents in cardiac tissue requires a higher field sensitivity, which can only be achieved by compromising spatial resolution. We developed a monolithic low-Tc niobium multiloop SQUID sensor, with sensor sizes ranging from 250μm to 1mm, and achieved sensitivities of 480-180fT /Hz1/2 in the white noise region for frequencies above 100Hz, respectively. For all sensor configurations, the spatial resolution was comparable to the effective diameter and limited by the sensor-to-sample spacing. Spatial registration allowed us to compare high-resolution images of magnetic fields associated with action currents and optical recordings of transmembrane potentials to study the bidomain nature of cardiac tissue or to match petrography to magnetic field maps in thin sections of geological samples.

JPRS Report Science & Technology Japan

DTIC Science & Technology

1989-06-02

Electronics •Superconducting Wiring in LSI •One Wafer Computer •Josephson Devices •SQUID Devices Infrared Sensor Magnetic Sensor •Superconducting...Guinier- de Wolff monochromatic focusing camera (CoK* radiation) and with Philips APD-10 auto-powder diffractometer (CuKÄ radiation). Pure Si was used as...crystallized and smooth surface. The values indicated in Fig. 2 were the thickness monitored by a quartz oscillating sensor located near the

Algorithm for Automatic Detection, Localization and Characterization of Magnetic Dipole Targets Using the Laser Scalar Gradiometer

DTIC Science & Technology

2016-06-01

TECHNICAL REPORT Algorithm for Automatic Detection, Localization and Characterization of Magnetic Dipole Targets Using the Laser Scalar...Automatic Detection, Localization and Characterization of Magnetic Dipole Targets Using the Laser Scalar Gradiometer Leon Vaizer, Jesse Angle, Neil...of Magnetic Dipole Targets Using LSG i June 2016 TABLE OF CONTENTS INTRODUCTION

Magnetic gradiometer for underwater detection applications

NASA Astrophysics Data System (ADS)

Kumar, S.; Skvoretz, D. C.; Moeller, C. R.; Ebbert, M. J.; Perry, A. R.; Ostrom, R. K.; Tzouris, A.; Bennett, S. L.; Czipott, P. V.; Sulzberger, G.; Allen, G. I.; Bono, J.; Clem, T. R.

2006-05-01

We have designed and constructed a magnetic gradiometer for underwater mine detection, location and tracking. The United States Naval Surface Warfare Center (NSWC PC) in Panama City, FL has conducted sea tests of the system using an unmanned underwater vehicle (UUV). The Real-Time Tracking Gradiometer (RTG) measures the magnetic field gradients caused by the presence of a mine in the Earth's magnetic field. These magnetic gradients can then be used to detect and locate a target with the UUV in motion. Such a platform can also be used for other applications, including the detection and tracking of vessels and divers for homeland (e.g., port) security and the detection of underwater pipelines. Data acquired by the RTG in sea tests is presented in this paper.

Research relative to the development of a cryogenic microwave cavity gradiometer for orbital use

NASA Technical Reports Server (NTRS)

Grossi, M. D.

1985-01-01

Technical approaches to increase the sensitivity of a non-cryogenic gradiometer toward the goal of 0.001 EU/square root of Hz, with solutions that have the potential of achieving an even more ambitious threshold, such as 0.0001 EU/square root of Hz are discussed. This goal can be achieved with a gradiometer design in which the proof masses are each suspended from two small arms, the torsion of which is directly related to the displacement of the sensing element. A negative-spring action, aimed at reducing the resonance frequency, is provided in this design by means of an external electrostatic field. This configuration of the instrument is also suitable for use in a tensorial arrangement.

A 20-channel magnetoencephalography system based on optically pumped magnetometers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Borna, Amir; Carter, Tony R.; Goldberg, Josh D.

In this paper, we describe a multichannel magnetoencephalography (MEG) system that uses optically pumped magnetometers (OPMs) to sense the magnetic fields of the human brain. The system consists of an array of 20 OPM channels conforming to the human subject's head, a person-sized magnetic shield containing the array and the human subject, a laser system to drive the OPM array, and various control and data acquisition systems. We conducted two MEG experiments: auditory evoked magnetic field and somatosensory evoked magnetic field, on three healthy male subjects, using both our OPM array and a 306-channel Elekta-Neuromag superconducting quantum interference device (SQUID)more » MEG system. The described OPM array measures the tangential components of the magnetic field as opposed to the radial component measured by most SQUID-based MEG systems. Finally, herein, we compare the results of the OPM- and SQUID-based MEG systems on the auditory and somatosensory data recorded in the same individuals on both systems.« less

A 20-channel magnetoencephalography system based on optically pumped magnetometers

DOE PAGES

Borna, Amir; Carter, Tony R.; Goldberg, Josh D.; ...

2017-10-16

In this paper, we describe a multichannel magnetoencephalography (MEG) system that uses optically pumped magnetometers (OPMs) to sense the magnetic fields of the human brain. The system consists of an array of 20 OPM channels conforming to the human subject's head, a person-sized magnetic shield containing the array and the human subject, a laser system to drive the OPM array, and various control and data acquisition systems. We conducted two MEG experiments: auditory evoked magnetic field and somatosensory evoked magnetic field, on three healthy male subjects, using both our OPM array and a 306-channel Elekta-Neuromag superconducting quantum interference device (SQUID)more » MEG system. The described OPM array measures the tangential components of the magnetic field as opposed to the radial component measured by most SQUID-based MEG systems. Finally, herein, we compare the results of the OPM- and SQUID-based MEG systems on the auditory and somatosensory data recorded in the same individuals on both systems.« less

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.

Beam current sensor

DOEpatents

Kuchnir, M.; Mills, F.E.

1984-09-28

A current sensor for measuring the dc component of a beam of charged particles employs a superconducting pick-up loop probe, with twisted superconducting leads in combination with a Superconducting Quantum Interference Device (SQUID) detector. The pick-up probe is in the form of a single-turn loop, or a cylindrical toroid, through which the beam is directed and within which a first magnetic flux is excluded by the Meisner effect. The SQUID detector acts as a flux-to-voltage converter in providing a current to the pick-up loop so as to establish a second magnetic flux within the electrode which nulls out the first magnetic flux. A feedback voltage within the SQUID detector represents the beam current of the particles which transit the pick-up loop. Meisner effect currents prevent changes in the magnetic field within the toroidal pick-up loop and produce a current signal independent of the beam's cross-section and its position within the toroid, while the combination of superconducting elements provides current measurement sensitivities in the nano-ampere range.

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.

Beam current sensor

DOEpatents

Kuchnir, Moyses; Mills, Frederick E.

1987-01-01

A current sensor for measuring the DC component of a beam of charged particles employs a superconducting pick-up loop probe, with twisted superconducting leads in combination with a Superconducting Quantum Interference Device (SQUID) detector. The pick-up probe is in the form of a single-turn loop, or a cylindrical toroid, through which the beam is directed and within which a first magnetic flux is excluded by the Meisner effect. The SQUID detector acts as a flux-to-voltage converter in providing a current to the pick-up loop so as to establish a second magnetic flux within the electrode which nulls out the first magnetic flux. A feedback voltage within the SQUID detector represents the beam current of the particles which transit the pick-up loop. Meisner effect currents prevent changes in the magnetic field within the toroidal pick-up loop and produce a current signal independent of the beam's cross-section and its position within the toroid, while the combination of superconducting elements provides current measurement sensitivites in the nano-ampere range.

Developments in Time-Division Multiplexing of X-ray Transition-Edge Sensors

NASA Astrophysics Data System (ADS)

Doriese, W. B.; Morgan, K. M.; Bennett, D. A.; Denison, E. V.; Fitzgerald, C. P.; Fowler, J. W.; Gard, J. D.; Hays-Wehle, J. P.; Hilton, G. C.; Irwin, K. D.; Joe, Y. I.; Mates, J. A. B.; O'Neil, G. C.; Reintsema, C. D.; Robbins, N. O.; Schmidt, D. R.; Swetz, D. S.; Tatsuno, H.; Vale, L. R.; Ullom, J. N.

2016-07-01

Time-division multiplexing (TDM) is a mature scheme for the readout of arrays of transition-edge sensors (TESs). TDM is based on superconducting-quantum-interference-device (SQUID) current amplifiers. Multiple spectrometers based on gamma-ray and X-ray microcalorimeters have been operated with TDM readout, each at the scale of 200 sensors per spectrometer, as have several astronomical cameras with thousands of sub-mm or microwave bolometers. Here we present the details of two different versions of our TDM system designed to read out X-ray TESs. The first has been field-deployed in two 160-sensor (8 columns × 20 rows) spectrometers and four 240-sensor (8 columns × 30 rows) spectrometers. It has a three-SQUID-stage architecture, switches rows every 320 ns, and has total readout noise of 0.41 μ Φ 0 / surd Hz. The second, which is presently under development, has a two-SQUID-stage architecture, switches rows every 160 ns, and has total readout noise of 0.19 μ Φ 0 / surd Hz. Both quoted noise values are non-multiplexed and referred to the first-stage SQUID. In a demonstration of this new architecture, a multiplexed 1-column × 32-row array of NIST TESs achieved average energy resolution of 2.55± 0.01 eV at 6 keV.

Code-division-multiplexed readout of large arrays of TES microcalorimeters

NASA Astrophysics Data System (ADS)

Morgan, K. M.; Alpert, B. K.; Bennett, D. A.; Denison, E. V.; Doriese, W. B.; Fowler, J. W.; Gard, J. D.; Hilton, G. C.; Irwin, K. D.; Joe, Y. I.; O'Neil, G. C.; Reintsema, C. D.; Schmidt, D. R.; Ullom, J. N.; Swetz, D. S.

2016-09-01

Code-division multiplexing (CDM) offers a path to reading out large arrays of transition edge sensor (TES) X-ray microcalorimeters with excellent energy and timing resolution. We demonstrate the readout of X-ray TESs with a 32-channel flux-summed code-division multiplexing circuit based on superconducting quantum interference device (SQUID) amplifiers. The best detector has energy resolution of 2.28 ± 0.12 eV FWHM at 5.9 keV and the array has mean energy resolution of 2.77 ± 0.02 eV over 30 working sensors. The readout channels are sampled sequentially at 160 ns/row, for an effective sampling rate of 5.12 μs/channel. The SQUID amplifiers have a measured flux noise of 0.17 μΦ0/√Hz (non-multiplexed, referred to the first stage SQUID). The multiplexed noise level and signal slew rate are sufficient to allow readout of more than 40 pixels per column, making CDM compatible with requirements outlined for future space missions. Additionally, because the modulated data from the 32 SQUID readout channels provide information on each X-ray event at the row rate, our CDM architecture allows determination of the arrival time of an X-ray event to within 275 ns FWHM with potential benefits in experiments that require detection of near-coincident events.

The Gravity Probe B `Niobium bird' experiment: Verifying the data reduction scheme for estimating the relativistic precession of Earth-orbiting gyroscopes

NASA Technical Reports Server (NTRS)

Uemaatsu, Hirohiko; Parkinson, Bradford W.; Lockhart, James M.; Muhlfelder, Barry

1993-01-01

Gravity Probe B (GP-B) is a relatively gyroscope experiment begun at Stanford University in 1960 and supported by NASA since 1963. This experiment will check, for the first time, the relativistic precession of an Earth-orbiting gyroscope that was predicted by Einstein's General Theory of Relativity, to an accuracy of 1 milliarcsecond per year or better. A drag-free satellite will carry four gyroscopes in a polar orbit to observe their relativistic precession. The primary sensor for measuring the direction of gyroscope spin axis is the SQUID (superconducting quantum interference device) magnetometer. The data reduction scheme designed for the GP-B program processes the signal from the SQUID magnetometer and estimates the relativistic precession rates. We formulated the data reduction scheme and designed the Niobium bird experiment to verify the performance of the data reduction scheme experimentally with an actual SQUID magnetometer within the test loop. This paper reports the results from the first phase of the Niobium bird experiment, which used a commercially available SQUID magnetometer as its primary sensor, and adresses the issues they raised. The first phase resulted in a large, temperature-dependent bias drift in the insensitive design and a temperature regulation scheme.

Effects of space weather on GOCE electrostatic gravity gradiometer measurements

NASA Astrophysics Data System (ADS)

Ince, E. Sinem; Pagiatakis, Spiros D.

2016-12-01

We examine the presence of residual nongravitational signatures in gravitational gradients measured by GOCE electrostatic gravity gradiometer. These signatures are observed over the magnetic poles during geomagnetically active days and can contaminate the trace of the gravitational gradient tensor by up to three to five times the expected noise level of the instrument (˜ 11 mE). We investigate these anomalies in the gradiometer measurements along many satellite tracks and examine possible causes using external datasets, such as interplanetary electric field measurements from the ACE (advanced composition explorer) and WIND spacecraft, and Poynting vector (flux) estimated from equivalent ionospheric currents derived from spherical elementary current systems over North America and Greenland. We show that the variations in the east-west and vertical electrical currents and Poynting vector components at the satellite position are highly correlated with the disturbances observed in the gradiometer measurements. The results presented in this paper reveal that the disturbances are due to intense ionospheric current variations that are enhanced by increased solar activity that causes a very dynamic drag environment. Moreover, successful modelling and removal of a high percentage of these disturbances are possible using external geomagnetic field observations.

Noise thermometry at ultra-low temperatures.

PubMed

Rothfuss, D; Reiser, A; Fleischmann, A; Enss, C

2016-03-28

The options for primary thermometry at ultra-low temperatures are rather limited. In practice, most laboratories are using (195)Pt NMR thermometers in the microkelvin range. In recent years, current sensing direct current superconducting quantum interference devices (DC-SQUIDs) have enabled the use of noise thermometry in this temperature range. Such devices have also demonstrated the potential for primary thermometry. One major advantage of noise thermometry is the fact that no driving current is needed to operate the device and thus the heat dissipation within the thermometer can be reduced to a minimum. Ultimately, the intrinsic power dissipation is given by the negligible back action of the readout SQUID. For thermometry in low-temperature experiments, current noise thermometers and magnetic flux fluctuation thermometers have proved to be most suitable. To make use of such thermometers at ultra-low temperatures, we have developed a cross-correlation technique that reduces the amplifier noise contribution to a negligible value. For this, the magnetic flux fluctuations caused by the Brownian motion of the electrons in our noise source are measured inductively by two DC-SQUID magnetometers simultaneously and the signals from these two channels are cross-correlated. Experimentally, we have characterized a thermometer made of a cold-worked high-purity copper cylinder with a diameter of 5 mm and a length of 20 mm for temperatures between 42 μK and 0.8 K. For a given temperature, a measuring time below 1 min is sufficient to reach a precision of better than 1%. The extremely low power dissipation in the thermometer allows continuous operation without heating effects. © 2016 The Author(s).

Global gravity survey by an orbiting gravity gradiometer

NASA Technical Reports Server (NTRS)

Paik, Ho Jung; Leung, Jurn-Sun; Morgan, Samuel H.; Parker, Joseph

1988-01-01

The scientific aims, design, and mission profile of the Superconducting Gravity Gradiometer Mission (SGGM), a NASA spacecraft mission proposed for the late 1990s, are discussed and illustrated with drawings and diagrams. SGGM would complement the two other planned gravimetry missions, GRM and Aristoteles, and would provide gravitational-field measurements with accuracy 2-3 mGal in 55 x 55-km blocks. The principal instruments are a (1) three-axis superconducting gravity gradiometer with intrinsic sensitivity 100 microeotvos/sq rt Hz, (2) a six-axis superconducting accelerometer with sensitivity 100 fg(E)/sq rt Hz linear and 10 prad/sec squared sq rt Hz angular, and (3) a six-axis shaker for active control of the platform. Consideration is given to the error budget and platform requirements, the orbit selection criteria, and the spacecraft design.

Active tensor magnetic gradiometer system final report for Project MM–1514

USGS Publications Warehouse

Smith, David V.; Phillips, Jeffrey D.; Hutton, S. Raymond

2014-01-01

An interactive computer simulation program, based on physical models of system sensors, platform geometry, Earth environment, and spheroidal magnetically-permeable targets, was developed to generate synthetic magnetic field data from a conceptual tensor magnetic gradiometer system equipped with an active primary field generator. The system sensors emulate the prototype tensor magnetic gradiometer system (TMGS) developed under a separate contract for unexploded ordnance (UXO) detection and classification. Time-series data from different simulation scenarios were analyzed to recover physical dimensions of the target source. Helbig-Euler simulations were run with rectangular and rod-like source bodies to determine whether such a system could separate the induced component of the magnetization from the remanent component for each target. This report concludes with an engineering assessment of a practical system design.

Ultra-Low Field SQUID-NMR using LN2 Cooled Cu Polarizing Field coil

NASA Astrophysics Data System (ADS)

Demachi, K.; Kawagoe, S.; Ariyoshi, S.; Tanaka, S.

2017-07-01

We are developing an Ultra-Low Field (ULF) Magnetic Resonance Imaging (MRI) system using a High-Temperature Superconductor superconducting quantum interference device (HTS rf-SQUID) for food inspection. The advantages of the ULF-NMR (Nuclear Magnetic Resonance) / MRI as compared with a conventional high field MRI are that they are compact and of low cost. In this study, we developed a ULF SQUID-NMR system using a polarizing coil to measure fat of which relaxation time T1 is shorter. The handmade polarizing coil was cooled by liquid nitrogen to reduce the resistance and accordingly increase the allowable current. The measured decay time of the polarizing field was 40 ms. The measurement system consisted of the liquid nitrogen cooled polarizing coil, a SQUID, a Cu wound flux transformer, a measurement field coil for the field of 47 μT, and an AC pulse coil for a 90°pulse field. The NMR measurements were performed in a magnetically shielded room to reduce the environmental magnetic field. The size of the sample was ϕ35 mm × L80 mm. After applying a polarizing field and a 90°pulse, an NMR signal was detected by the SQUID through the flux transformer. As a result, the NMR spectra of fat samples were obtained at 2.0 kHz corresponding to the measurement field Bm of 47 μT. The T1 relaxation time of the mineral oil measured in Bm was 45 ms. These results suggested that the ULF-NMR/MRI system has potential for food inspection.

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

NASA Astrophysics Data System (ADS)

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

2018-01-01

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

Advanced superconducting gradiometers for mine detection

NASA Astrophysics Data System (ADS)

Clem, Ted R.

1996-05-01

Sensors incorporating superconducting quantum interference devices provide the greatest sensitivity for magnetic anomaly detection available with current technology. During the 1980s, the Coastal Systems Station (CSS) developed a superconducting magnetic gradiometer capable of operation outside of the laboratory environment. With this sensor, the CSS was able to demonstrate buried mine detection for the U.S. Navy. Subsequently, the sensor was incorporated into a multisensor suite onboard an underwater towed vehicle to provide a robust mine hunting capability for the Magnetic and Acoustic Detection of Mines Project. This sensor using thin film niobium and a new liquid helium cooling concept was developed to provide significant increases in sensitivity and detection range. In the late 1980s, a new class of `high- Tc' superconductor were discovered with critical temperatures above the boiling point of liquid nitrogen (77 K). This advance has opened up new opportunities for mine reconnaissance and hunting, especially for operation onboard small unmanned underwater vehicles. A high-Tc sensor concept using liquid nitrogen refrigeration has been developed and a test article of that concept is currently being evaluated for its applicability to mobile operation. The design principles for the two new sensor approaches and the results of their evaluations will be described. Finally, the implications of these advances to mine reconnaissance and hunting will be discussed.

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.

NMR and MRI apparatus and method

DOEpatents

Clarke, John; Kelso, Nathan; Lee, SeungKyun; Moessle, Michael; Myers, Whittier; McDermott, Robert; ten Haken, Bernard; Pines, Alexander; Trabesinger, Andreas

2007-03-06

Nuclear magnetic resonance (NMR) signals are detected in microtesla fields. Prepolarization in millitesla fields is followed by detection with an untuned dc superconducting quantum interference device (SQUID) magnetometer. Because the sensitivity of the SQUID is frequency independent, both signal-to-noise ratio (SNR) and spectral resolution are enhanced by detecting the NMR signal in extremely low magnetic fields, where the NMR lines become very narrow even for grossly inhomogeneous measurement fields. Additional signal to noise benefits are obtained by use of a low noise polarization coil, comprising litz wire or superconducting materials. MRI in ultralow magnetic field is based on the NMR at ultralow fields. Gradient magnetic fields are applied, and images are constructed from the detected NMR signals.

Imaging the Working Brain.

ERIC Educational Resources Information Center

Swithenby, S. J.

1996-01-01

Very sensitive SQUID (superconducting quantum interference device) detectors are used in the technique known as magnetoencephalography to provide dynamic images of the brain. This can help our fundamental understanding of the way the brain works and may be of particular use in treating disorders such as epilepsy. (Author/MKR)

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

NASA Astrophysics Data System (ADS)

Prele, D.

2015-08-01

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

An ultra-sensitive and wideband magnetometer based on a superconducting quantum interference device

NASA Astrophysics Data System (ADS)

Storm, Jan-Hendrik; Hömmen, Peter; Drung, Dietmar; Körber, Rainer

2017-02-01

The magnetic field noise in superconducting quantum interference devices (SQUIDs) used for biomagnetic research such as magnetoencephalography or ultra-low-field nuclear magnetic resonance is usually limited by instrumental dewar noise. We constructed a wideband, ultra-low noise system with a 45 mm diameter superconducting pick-up coil inductively coupled to a current sensor SQUID. Thermal noise in the liquid helium dewar is minimized by using aluminized polyester fabric as superinsulation and aluminum oxide strips as heat shields. With a magnetometer pick-up coil in the center of the Berlin magnetically shielded room 2 (BMSR2), a noise level of around 150 aT Hz-1/2 is achieved in the white noise regime between about 20 kHz and the system bandwidth of about 2.5 MHz. At lower frequencies, the resolution is limited by magnetic field noise arising from the walls of the shielded room. Modeling the BMSR2 as a closed cube with continuous μ-metal walls, we can quantitatively reproduce its measured field noise.

Quasi-molecular bosonic complexes-a pathway to SQUID with controlled sensitivity

NASA Astrophysics Data System (ADS)

Safavi-Naini, Arghavan; Capogrosso-Sansone, Barbara; Kuklov, Anatoly; Penna, Vittorio

2016-02-01

Recent experimental advances in realizing degenerate quantum dipolar gases in optical lattices and the flexibility of experimental setups in attaining various geometries offer the opportunity to explore exotic quantum many-body phases stabilized by anisotropic, long-range dipolar interaction. Moreover, the unprecedented control over the various physical properties of these systems, ranging from the quantum statistics of the particles, to the inter-particle interactions, allow one to engineer novel devices. In this paper, we consider dipolar bosons trapped in a stack of one-dimensional optical lattice layers, previously studied in (Safavi-Naini et al 2014 Phys. Rev. A 90 043604). Building on our prior results, we provide a description of the quantum phases stabilized in this system which include composite superfluids (CSFs), solids, and supercounterfluids, most of which are found to be threshold-less with respect to the dipolar interaction strength. We also demonstrate the effect of enhanced sensitivity to rotations of a SQUID-type device made of two CSF trapped in a ring-shaped optical lattice layer with weak links.

Modeling and Error Analysis of a Superconducting Gravity Gradiometer.

DTIC Science & Technology

1979-08-01

fundamental limit to instrument - -1- sensitivity is the thermal noise of the sensor . For the gradiometer design outlined above, the best sensitivity...Mapoles at Stanford. Chapter IV determines the relation between dynamic range, the sensor Q, and the thermal noise of the cryogenic accelerometer. An...C.1 Accelerometer Optimization (1) Development and optimization of the loaded diaphragm sensor . (2) Determination of the optimal values of the

ALLTEM Multi-Axis Electromagnetic Induction System Demonstration and Validation

DTIC Science & Technology

2012-08-01

threshold T-high higher threshold TMGS Tensor Magnetic Gradiometer System TOI target of interest Tx ALLTEM transmitter USGS U.S. Geological...the Tensor Magnetic Gradiometer System ( TMGS ) and two prototype EMI instruments, the Very Early Time-domain ElectroMagnetic (VETEM) system and the...project one prototype magnetic system, the TMGS , and two prototype EMI instruments, VETEM and the High Frequency Sounder, were evaluated. Subsequent

Accuracy of mapping the Earth's gravity field fine structure with a spaceborne gravity gradiometer mission

NASA Technical Reports Server (NTRS)

Kahn, W. D.

1984-01-01

The spaceborne gravity gradiometer is a potential sensor for mapping the fine structure of the Earth's gravity field. Error analyses were performed to investigate the accuracy of the determination of the Earth's gravity field from a gravity field satellite mission. The orbital height of the spacecraft is the dominating parameter as far as gravity field resolution and accuracies are concerned.

Simulation-based evaluation of a cold atom interferometry gradiometer concept for gravity field recovery

NASA Astrophysics Data System (ADS)

Douch, Karim; Wu, Hu; Schubert, Christian; Müller, Jürgen; Pereira dos Santos, Franck

2018-03-01

The prospects of future satellite gravimetry missions to sustain a continuous and improved observation of the gravitational field have stimulated studies of new concepts of space inertial sensors with potentially improved precision and stability. This is in particular the case for cold-atom interferometry (CAI) gradiometry which is the object of this paper. The performance of a specific CAI gradiometer design is studied here in terms of quality of the recovered gravity field through a closed-loop numerical simulation of the measurement and processing workflow. First we show that mapping the time-variable field on a monthly basis would require a noise level below 5mE /√{Hz } . The mission scenarios are therefore focused on the static field, like GOCE. Second, the stringent requirement on the angular velocity of a one-arm gradiometer, which must not exceed 10-6 rad/s, leads to two possible modes of operation of the CAI gradiometer: the nadir and the quasi-inertial mode. In the nadir mode, which corresponds to the usual Earth-pointing satellite attitude, only the gradient Vyy , along the cross-track direction, is measured. In the quasi-inertial mode, the satellite attitude is approximately constant in the inertial reference frame and the 3 diagonal gradients Vxx,Vyy and Vzz are measured. Both modes are successively simulated for a 239 km altitude orbit and the error on the recovered gravity models eventually compared to GOCE solutions. We conclude that for the specific CAI gradiometer design assumed in this paper, only the quasi-inertial mode scenario would be able to significantly outperform GOCE results at the cost of technically challenging requirements on the orbit and attitude control.

Progress towards a space-borne quantum gravity gradiometer

NASA Technical Reports Server (NTRS)

Yu, Nan; Kohel, James M.; Ramerez-Serrano, Jaime; Kellogg, James R.; Lim, Lawrence; Maleki, Lute

2004-01-01

Quantum interferometer gravity gradiometer for 3D mapping is a project for developing the technology of atom interferometer-based gravity sensor in space. The atom interferometer utilizes atomic particles as free fall test masses to measure inertial forces with unprecedented sensitivity and precision. It also allows measurements of the gravity gradient tensor components for 3D mapping of subsurface mass distribution. The overall approach is based on recent advances of laser cooling and manipulation of atoms in atomic and optical physics. Atom interferometers have been demonstrated in research laboratories for gravity and gravity gradient measurements. In this approach, atoms are first laser cooled to micro-kelvin temperatures. Then they are allowed to freefall in vacuum as true drag-free test masses. During the free fall, a sequence of laser pulses is used to split and recombine the atom waves to realize the interferometric measurements. We have demonstrated atom interferometer operation in the Phase I period, and we are implementing the second generation for a complete gradiometer demonstration unit in the laboratory. Along with this development, we are developing technologies at component levels that will be more suited for realization of a space instrument. We will present an update of these developments and discuss the future directions of the quantum gravity gradiometer project.

High Resolution Imaging with MUSTANG-2 on the GBT

NASA Astrophysics Data System (ADS)

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

2018-01-01

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

Material Structure of a Graded Refractive Index Lens in Decapod Squid

NASA Astrophysics Data System (ADS)

Cai, Jing; Heiney, Paul; Sweeney, Alison

2013-03-01

Underwater vision with a camera-type eye that is simultaneously acute and sensitive requires a spherical lens with a graded distribution of refractive index. Squids have this type of lens, and our previous work has shown that its optical properties are likely achieved with radially variable densities of a single protein with multiple isoforms. Here we measure the spatial organization of this novel protein material in concentric layers of the lens and use these data to suggest possible mechanisms of self-assembly of the proteins into a graded refractive index structure. First, we performed small angle x-ray scattering (SAXS) to study how the protein is spatially organized. Then, molecular dynamic simulation allowed us to correlate structure to the possible dynamics of the system in different regions of the lens. The combination of simulation and SAXS data in this system revealed the likely protein-protein interactions, resulting material structure and its relationship to the observed and variable optical properties of this graded index system. We believe insights into the material properties of the squid lens system will inform the invention of self-assembling graded index devices.

Noninvasive liver iron measurements with a room-temperature susceptometer

PubMed Central

Avrin, W F; Kumar, S

2011-01-01

Magnetic susceptibility measurements on the liver can quantify iron overload accurately and noninvasively. However, established susceptometer designs, using Superconducting QUantum Interference Devices (SQUIDs) that work in liquid helium, have been too expensive for widespread use. This paper presents a less expensive liver susceptometer that works at room temperature. This system uses oscillating magnetic fields, which are produced and detected by copper coils. The coil design cancels the signal from the applied field, eliminating noise from fluctuations of the source-coil current and sensor gain. The coil unit moves toward and away from the patient at 1 Hz, cancelling drifts due to thermal expansion of the coils. Measurements on a water phantom indicated instrumental errors less than 30 μg of iron per gram of wet liver tissue, which is small compared with other errors due to the response of the patient’s body. Liver iron measurements on eight thalassemia patients yielded a correlation coefficient r=0.98 between the room-temperature susceptometer and an existing SQUID. These results indicate that the fundamental accuracy limits of the room-temperature susceptometer are similar to those of the SQUID. PMID:17395991

High Tc SQUIDs and eddy-current NDE: a comprehensive investigation from real data to modelling

NASA Astrophysics Data System (ADS)

Ruosi, A.; Valentino, M.; Pepe, G.; Monebhurrun, V.; Lesselier, D.; Duchêne, B.

2000-11-01

The interest in magnetometry for eddy-current non-destructive testing, e.g. of planar conductive structures encountered in the aircraft industry, using high-temperature superconducting quantum interference devices (SQUIDs) is primarily due to their high sensitivity to magnetic flux even at very low frequencies. Here it is shown how theoretical, numerical and measurement machineries are combined to get reasonable synthetic and experimental data and to reach a good understanding of the interaction of diffusive wavefields with a damaged non-magnetic metal plate (as a first step towards the retrieval of pertinent features of the defects). The measurement modalities are considered first. It is illustrated in some detail how laboratory-controlled experiments are performed by a SQUID-based probe displaced above artificially damaged plates. Experimental data are then confronted with simulation results in order to evaluate the accuracy and reliability of this measurement system. Simulations are carried out by a computationally fast vector volume integral method dedicated to a planar layering affected by a volumetric defect, which involves the construction of the dyadic Green system of the layering.

The State of the Industry and Research in Airborne Geophysics

NASA Astrophysics Data System (ADS)

Hodges, G.

2007-12-01

Development of airborne geophysical methods has tended to proceed in rushes of energy, when many new systems are developed for the same application simultaneously along many pathways. The tremendous growth of airborne EM through the '50s to '70s was followed by natural selection in the '80s and '90s down to two styles: fixed-wing aircraft with high-powered time domain systems (FTEM) offering depth of exploration but poor spatial resolution, and helicopter-borne frequency-domain systems (HFEM) offering the best resolution but poor depth of exploration. At the end of the '90s there was an incredible spurt of energy toward helicopter time domain development, spurred technological advances in electronics and materials. By 2007 there were 8 systems operational. Perhaps the most daring current research is toward airborne EM systems utilizing ambient EM fields as sources. Magnetic sensors are almost universally cesium-vapor total field sensors (0.01nT sampled at 0.1s). Because the limitation on target detection is ambient, in-band noise, there is little to gain from producing higher-sensitivity meters. Data quality improvements are being sought by measuring horizontal and vertical gradients more accurately. The new wave of research for magnetic surveys is the measurement of vector or tensor magnetic data with directional sensors, generally either fluxgates or SQUIDS. Magnetometers on autonomous aircraft are newly available. Gamma Ray Spectrometry surveys with sodium-iodide crystal detectors give good performance, and the low cost allows for large volumes to make up for the relatively low sensitivity. The last few years have seen development of new systems in which each crystal in the detector array is monitored, calibrated and stabilized individually using natural radiation. Airborne gravity systems available use the LaCoste zero-length pendulum, or orthogonal accelerometers. Separation of gravity from acceleration is generally done with platforms stabilized for both rotation and translation, and measurement of acceleration. Generally, solutions must be a trade-off between sensitivity and spatial resolution, restricting their application to the large structures of oil exploration. Airborne gravity gradiometry (AGG) achieves higher resolution and sensitivity with meters based on the system of accelerometers on spinning disks, implemented as horizontal gradiometers and as full tensor gradiometers. Putting the sensor on a helicopter improved the data S/N. An airship implementation promises to be a near-ideal platform, restricted by the payload limits. Many projects are on-going to develop new gravity gradiometers toward a goal of 1Eotvös sensitivity at 100m wavelength. Hyperspectral imaging measures the reflected light from the surface across a broad spectrum, originally from near-infrared through visible, but now often including thermal infrared. The research challenges for systems have been to stabilize the system sensitivities, correct for varying ambient light levels reflectance, and improve resolution without degrading signal strength. Data processing requires the determination of the mineral reflectance spectra that best fit the spectrum of each pixel, when each pixel will probably contain many minerals, or be partly covered by vegetation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shao Xiaoqiang; Wang Hongfu; Zhang Shou

We present an approach for implementation of a 1->3 orbital state quantum cloning machine based on the quantum Zeno dynamics via manipulating three rf superconducting quantum interference device (SQUID) qubits to resonantly interact with a superconducting cavity assisted by classical fields. Through appropriate modulation of the coupling constants between rf SQUIDs and classical fields, the quantum cloning machine can be realized within one step. We also discuss the effects of decoherence such as spontaneous emission and the loss of cavity in virtue of master equation. The numerical simulation result reveals that the quantum cloning machine is especially robust against themore » cavity decay, since all qubits evolve in the decoherence-free subspace with respect to cavity decay due to the quantum Zeno dynamics.« less

Standardized UXO Technology Demonstration Site Open Field Scoring Record No. 908

DTIC Science & Technology

2008-08-01

demonstration at Aberdeen Proving Ground, a system with eight fluxgate magnetometers (Foerster CON650 gradiometers) and RTK-DGPS georeferencing will...be used. The spacing between the individual fluxgate sensors will be 25 cm (ca. 10 inches), totaling to a swath width of 2 m. c. The MAGNETO...MX system consists of: the MX-compact hardware multiplexer electronic module, up to 32 fluxgate gradiometers (for the APG demonstration: 8 fluxgate

Portable Magnetic Gradiometer for Real-Time Localization and Classification of Unexploded Ordnance

DTIC Science & Technology

2006-09-01

classification (DLC) of Unexploded Ordnance (UXO). The portable gradiometer processes data from triaxial fluxgate magnetometers to develop sets of...low-noise (ង pTrms/√Hz) fluxgate -type Triaxial Magnetometers (TM). Paired sets of TMs comprise magnetic gradient sensor “axes” of the array that...channels of analog B-field data. The digitizers can be locked to the Global Positioning System to provide; a) Precise sensor channel timing, and b

Measuring attitude with a gradiometer

NASA Technical Reports Server (NTRS)

Sonnabend, David; Gardner, Thomas G.

1994-01-01

This paper explores using a gravity gradiometer to measure the attitude of a satellite, given that the gravity field is accurately known. Since gradiometers actually measure a combination of the gradient and attitude rate and acceleration terms, the answer is far from obvious. The paper demonstrates that it can be done and at microradian accuracy. The technique employed is dynamic estimation, based on the momentum biased Euler equations. The satellite is assumed nominally planet pointed, and subject to control, gravity gradient, and partly radom drag torques. The attitude estimator is unusual. While the standard method of feeding back measurement residuals is used, the feedback gain matrix isn't derived from Kalman theory. instead, it's chosen to minimize a measure of the terminal covariance of the error in the estimate. This depends on the gain matrix and the power spectra of all the process and measurement noises. An integration is required over multiple solutions of Lyapunov equations.

Analogue Hawking radiation in a dc-SQUID array transmission line.

PubMed

Nation, P D; Blencowe, M P; Rimberg, A J; Buks, E

2009-08-21

We propose the use of a superconducting transmission line formed from an array of direct-current superconducting quantum interference devices for investigating analogue Hawking radiation. Biasing the array with a space-time varying flux modifies the propagation velocity of the transmission line, leading to an effective metric with a horizon. Being a fundamentally quantum mechanical device, this setup allows for investigations of quantum effects such as backreaction and analogue space-time fluctuations on the Hawking process.

Development of device for quantifying magnetic nanoparticle tracers accumulating in sentinel lymph nodes

NASA Astrophysics Data System (ADS)

Kuwahata, Akihiro; Kaneko, Miki; Chikaki, Shinichi; Kusakabe, Moriaki; Sekino, Masaki

2018-05-01

The developed device with electromagnetic coils and small permanent magnets quantifies the iron contents of superparamagnetic iron oxide nanoparticles for sentinel lymph node (SLN) biopsy. To remove diamagnetic and paramagnetic components and detect only superparamagnetic components, a 2nd harmonics signal is detected by a gradiometer under a moderate AC magnetic field (1-2 mT) with the fundamental frequency (2.944 kHz) of the coils and DC magnetic field (1-2 mT) of the magnets. The detection limit with a signal-to-noise ratio of 5 is approximately 0.28 μg of iron, and the device has a wide dynamic range of 104, 0.28 μg-2.8 mg. Additional coils and permanent magnets play an important role producing the optimum distribution of AC/DC magnetic fields for an iron distribution-independent and SLN size-independent quantification. We demonstrated the quantification of the iron in phantoms, which have a size of 3-20 mm with varied iron distributions and contain magnetic nanoparticles numerically. These results indicate that the developed device is useful for quantifying the magnetic nanoparticles accumulating in SLNs.

Prototyping a new, high-temperature SQUID magnetometer system

NASA Astrophysics Data System (ADS)

Grappone, J. Michael; Shaw, John; Biggin, Andrew J.

2017-04-01

High-sensitivity Superconducting Quantum Inference Devices (SQUIDs) and μ-metal shielding have largely solved paleomagnetic noise problems. Combing the two allows successful measurements of previously unusable samples, generally sediments with very weak (<10 pAm2) magnetizations. The improved sensitivity increases the fidelity of magnetic field variation surveys, but surveys continue to be somewhat slow. SQUIDs have historically been expensive to buy and operate, but technological advances now allow them to operate at liquid nitrogen temperatures (77 K), drastically reducing their costs. Step-wise thermal paleomagnetics studies cause large lag times during later steps as a result of heating from and cooling to room temperature for measurements. If the cooling step is removed entirely, however, the lag time drops by at least half. Available magnetometers currently provide either SQUID-level (0.1 - 1 pAm2) sensitivity or continuous heating. Combining a SQUID magnetometer with a high temperature oven is the logical next step to uncover the mysteries of the paleofield. However, the few that currently offer high temperature capabilities with noise levels approaching 10 pAm2 require either spinning or vibrating the sample, necessitating additional handling and potentially causing damage to the sample. Two primary factors have plagued previous developments: noise levels and temperature gradients. Our entire system is shielded from the environment using 4 layers of μ-metal. Our sample oven (designed for 7 mm diameter samples) sits inside a copper pipe and operates at high-frequency AC voltages. High frequency (10 kHz) AC current reduces the skin depth of radio frequency (RF) electromagnetic noise, which allows the 2 mm-thick copper shielding to reduce RF noise by ˜94%, leaving a residual field of ˜1.5 nT at the SQUID's location, 14.9 mm from the oven. A computer-controlled Eurotherm 3216 thermal controller regulates the temperature within ± 0.5 ˚ C. To reach 700 ˚ C, just above the Curie temperature of Hematite, a temperature difference of nearly 900 ˚ C between the sample and the SQUID is required. Since dipole fields decay rapidly with distance (∝ r -3 ), the equipment is designed to handle temperature gradients above 500 ˚ C cm-1 for maximum sensitivity using a passive double-vacuum separation system. All the parts used are commercially available to help reduce the operating costs and increase versatility.

High temperature superconductor micro-superconducting-quantum-interference-device magnetometer for magnetization measurement of a microscale magnet.

PubMed

Takeda, Keiji; Mori, Hatsumi; Yamaguchi, Akira; Ishimoto, Hidehiko; Nakamura, Takayoshi; Kuriki, Shinya; Hozumi, Toshiya; Ohkoshi, Shin-ichi

2008-03-01

We have developed a high temperature superconductor (HTS) micrometer-sized dc superconducting quantum interference device (SQUID) magnetometer for high field and high temperature operation. It was fabricated from YBa2Cu3O7-delta of 92 nm in thickness with photolithography techniques to have a hole of 4x9 microm2 and 2 microm wide grain boundary Josephson junctions. Combined with a three dimensional magnetic field coil system, the modulation patterns of critical current Ic were observed for three different field directions. They were successfully used to measure the magnetic properties of a molecular ferrimagnetic microcrystal (23x17x13 microm3), [Mn2(H2O)2(CH3COO)][W(CN)8]2H2O. The magnetization curve was obtained in magnetic field up to 0.12 T between 30 and 70 K. This is the first to measure the anisotropy of hysteresis curve in the field above 0.1 T with an accuracy of 10(-12) J T(-1) (10(-9) emu) with a HTS micro-SQUID magnetometer.

Performance of an on-chip superconducting circulator for quantum microwave systems

NASA Astrophysics Data System (ADS)

Chapman, Benjamin; Rosenthal, Eric; Moores, Bradley; Kerckhoff, Joseph; Mates, J. A. B.; Hilton, G. C.; Vale, L. R.; Ullom, J. N.; LalumíEre, Kevin; Blais, Alexandre; Lehnert, K. W.

Microwave circulators enforce a single propagation direction for signals in an electrical network. Unfortunately, commercial circulators are bulky, lossy, and cannot be integrated close to superconducting circuits because they require strong ( kOe) magnetic fields produced by permanent magnets. Here we report on the performance of an on-chip, active circulator for superconducting microwave circuits, which uses no permanent magnets. Non-reciprocity is achieved by actively modulating reactive elements around 100 MHz, giving roughly a factor of 50 in the separation between signal and control frequencies, which facilitates filtering. The circulator's active components are dynamically tunable inductors constructed with arrays of dc-SQUIDs in series. Array inductance is tuned by varying the magnetic flux through the SQUIDs with fields weaker than 1 Oe. Although the instantaneous bandwidth of the device is narrow, the operation frequency is tunable between 4 and 8 GHz. This presentation will describe the device's theory of operation and compare its measured performance to design goals. This work is supported by the ARO under contract W911NF-14-1-0079 and the National Science Foundation under Grant Number 1125844.

Proceedings of the Annual Conference on Magnetism and Magnetic Materials (38th) Held at Minneapolis, Minnesota on 15-18 November 1993. (Journal of Applied Physics. Volume 75, Number 10, Part 28

DTIC Science & Technology

1994-05-15

Nogues superconducting quantum interference device magnetometry and small-angle neutron-scattering techniques 5829 Thermodynamical properties of a...sa’nple magnetometer (VSM) and superconducting Coey et al.1 have been extensively studied during the past quantum interference device (SQUID) were used to...were measured in a superconducting quantum- interference 30 device magnetometer at 273 K. 20 e 10 U1 Y3 U RESULTS - C0 20 40 60 80 100 Phase relations

The DCU: the detector control unit of the SAFARI instrument onboard SPICA

NASA Astrophysics Data System (ADS)

Clénet, A.; Ravera, L.; Bertrand, B.; Cros, A.; Hou, R.; Jackson, B. D.; van Leeuwen, B. J.; Van Loon, D.; Parot, Y.; Pointecouteau, E.; Sournac, A.; Ta, N.

2012-09-01

The SpicA FAR infrared Instrument (SAFARI) is a European instrument for the infrared domain telescope SPICA, a JAXA space mission. The SAFARI detectors are Transistor Edge Sensors (TES) arranged in 3 matrixes. The TES front end electronic is based on Superconducting Quantum Interference Devices (SQUIDs) and it does the readout of the 3500 detectors with Frequency Division Multiplexing (FDM) type architecture. The Detector Control Unit (DCU), contributed by IRAP, manages the readout of the TES by computing and providing the AC-bias signals (1 - 3 MHz) to the TES and by computing the demodulation of the returning signals. The SQUID being highly non-linear, the DCU has also to provide a feedback signal to increase the SQUID dynamic. Because of the propagation delay in the cables and the processing time, a classic feedback will not be stable for AC-bias frequencies up to 3 MHz. The DCU uses a specific technique to compensate for those delays: the BaseBand FeedBack (BBFB). This digital data processing is done for the 3500 pixels in parallel. Thus, to keep the DCU power budget within its allocation we have to specifically optimize the architecture of the digital circuit with respect to the power consumption. In this paper we will mainly present the DCU architecture. We will particularly focus on the BBFB technique used to linearize the SQUID and on the optimization done to reduce the power consumption of the digital processing circuit.

Magnetic tracking for TomoTherapy systems: gradiometer based methods to filter eddy-current magnetic fields.

PubMed

McGary, John E; Xiong, Zubiao; Chen, Ji

2013-07-01

TomoTherapy systems lack real-time, tumor tracking. A possible solution is to use electromagnetic markers; however, eddy-current magnetic fields generated in response to a magnetic source can be comparable to the signal, thus degrading the localization accuracy. Therefore, the tracking system must be designed to account for the eddy fields created along the inner bore conducting surfaces. The aim of this work is to investigate localization accuracy using magnetic field gradients to determine feasibility toward TomoTherapy applications. Electromagnetic models are used to simulate magnetic fields created by a source and its simultaneous generation of eddy currents within a conducting cylinder. The source position is calculated using a least-squares fit of simulated sensor data using the dipole equation as the model equation. To account for field gradients across the sensor area (≈ 25 cm(2)), an iterative method is used to estimate the magnetic field at the sensor center. Spatial gradients are calculated with two arrays of uniaxial, paired sensors that form a gradiometer array, where the sensors are considered ideal. Experimental measurements of magnetic fields within the TomoTherapy bore are shown to be 1%-10% less than calculated with the electromagnetic model. Localization results using a 5 × 5 array of gradiometers are, in general, 2-4 times more accurate than a planar array of sensors, depending on the solenoid orientation and position. Simulation results show that the localization accuracy using a gradiometer array is within 1.3 mm over a distance of 20 cm from the array plane. In comparison, localization errors using single array are within 5 mm. The results indicate that the gradiometer method merits further studies and work due to the accuracy achieved with ideal sensors. Future studies should include realistic sensor models and extensive numerical studies to estimate the expected magnetic tracking accuracy within a TomoTherapy system before proceeding with prototype development.

Test Evaluation and Modification of Prototype Rotating Gravity Gradiometer

DTIC Science & Technology

1975-07-01

RECOMMENEATIONS 3 4.0 BEARINGS 6 4.1 Design 6 4.2 Metrology 6 4.3 Preassembly 14 5.0 TEST RIG 17 5.1 Design 17 5.2 Metrology 21 5.3 Assembly and...print requirements of 5 \\i inches TIR max. However, because of available (stare-of-the-art) metrology equipment limitations, no conclusion as to...gravity gradiometer are contained in Shaker Research Corporation drawing series 101 (see Appendix I), 4.2 Metrology The production of the

Tests of general relativity in earth orbit using a superconducting gravity gradiometer

NASA Technical Reports Server (NTRS)

Paik, H. J.

1989-01-01

Interesting new tests of general relativity could be performed in earth orbit using a sensitive superconducting gravity gradiometer under development. Two such experiments are discussed here: a null test of the tracelessness of the Riemann tensor and detection of the Lense-Thirring term in the earth's gravity field. The gravity gradient signals in various spacecraft orientations are derived, and dominant error sources in each experimental setting are discussed. The instrument, spacecraft, and orbit requirements imposed by the experiments are derived.

Measuring attitude with a gradiometer

NASA Technical Reports Server (NTRS)

Sonnabend, David; Born, George H.

1994-01-01

Static attitude estimation and dynamic attitude estimation are used to describe a gradiometer composed of a number of accelerometers that are used to measure a combination of the local gravity gradient and instrument rotation effects. After a series of measures to isolate the gradient, a global mesh of measurements can be obtained that determine the planetary external gravity potential. Orbital and spacecraft models are developed to determine if, when the gravity potential is known, the same measurements, unsupported by any other information can be used to infer the spacecraft attitude.

SQUID readout and ultra-low magnetic fields for Gravity Probe-B (GP-B)

NASA Technical Reports Server (NTRS)

Lockhart, James M.

1986-01-01

The superconducting readout system to be used for resolving 0.001 arcsec changes in the gyroscope spin direction in the Relativity Gyroscope (GP-B) experiment is described. This system couples the London magnetic moment flux of the spinning gyro to a low noise superconducting quantum interference device (SQUID) detector. Resolution limits and noise performance of the detection system are discussed, and improvements obtained and expected with advanced SQUIDs are presented. Also described is the novel use of superconducting magnetic shielding techniques to obtain a 250 dB attenuation of the earth's magnetic field at the location of the gyroscopes. In this approach, expanded superconducting foil shields are coupled with fixed cylindrical superconducting shields and special geometric considerations to obtain the extremely high attenuation factor required. With these shielding techniques, it appears that the 0.5-Gauss earth field (which appears to the gyroscopes as an ac field at the satellite roll rate) can be reduced to the 10 to the -13th G level required by the experiment. Recent results concerning improvements in the performance of the superconducting foil techniques obtained with the use of a new computer-controlled cooling system are presented.

High-sensitivity cooled coil system for nuclear magnetic resonance in kHz range

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Tingting; Zhao, Jing, E-mail: zhaojing-8239@jlu.edu.cn; Peter Grünberg Institute

2014-11-15

In several low-field Nuclear Magnetic Resonance (LF-NMR) and surface nuclear magnetic resonance applications, i.e., in the frequency range of kHz, high sensitivity magnetic field detectors are needed. Usually, low-T{sub c} superconducting quantum interference devices (SQUIDs) with a high field sensitivity of about 1 fT/Hz{sup 1/2} are employed as detectors. Considering the flux trapping and operational difficulties associated with low-T{sub c} SQUIDs, we designed and fabricated liquid-nitrogen-cooled Cu coils for NMR detection in the kHz range. A cooled coil system consisting of a 9-cm diameter Cu coil and a low noise preamplifier was systematically investigated and reached a sensitivity of 2more » fT/Hz{sup 1/2} at 77 K, which is 3 times better compared to the sensitivity at 300 K. A Q-switch circuit as an essential element for damping the ringing effects of the pickup coil was developed to acquire free induction decay signals of a water sample with minimum loss of signal. Our studies demonstrate that cooled Cu coils, if designed properly, can provide a comparable sensitivity to low-T{sub c} SQUIDs.« less

Development of an Atom Interferometer Gravity Gradiometer for Earth Sciences

NASA Technical Reports Server (NTRS)

Rakholia, A.; Sugarbaker, A.; Black, A.; Kasecivh, M.; Saif, B.; Luthcke, S.; Callahan, L.; Seery, B.; Feinberg, L.; Mather, J.;

Fabrication and Evaluation of Superconducting and Semiconducting Materials

DTIC Science & Technology

1993-09-01

Laboratory Material Physics Branch by conducting investigations into the properties of superconducting , magnetic , and other solid state materials. Studies...Physics Branch in conducting research into applied problems such as the design of magnetic shielding and superconducting quantum interference device...SQUID) magnetometry detection of magnetic anomalies. SFA provided research assistance in the areas of bulk ceramic sample preparation. conversion

Superconducting Quantum Interference Device Array Based High Frequency Direction Finding on an Airborne Platform

DTIC Science & Technology

is performed using the MUSIC algorithm on the signals received on the non-uniform phased array, and the ESPRIT algorithm is used on the signals...received on the non-colocated vector sensor. The simulation results show that the MUSIC algorithm using 2D Bi-SQUIDs is able to differentiate two signals

Assessing the trophic position and ecological role of squids in marine ecosystems by means of food-web models

NASA Astrophysics Data System (ADS)

Coll, Marta; Navarro, Joan; Olson, Robert J.; Christensen, Villy

2013-10-01

We synthesized available information from ecological models at local and regional scales to obtain a global picture of the trophic position and ecological role of squids in marine ecosystems. First, static food-web models were used to analyze basic ecological parameters and indicators of squids: biomass, production, consumption, trophic level, omnivory index, predation mortality diet, and the ecological role. In addition, we developed various dynamic temporal simulations using two food-web models that included squids in their parameterization, and we investigated potential impacts of fishing pressure and environmental conditions for squid populations and, consequently, for marine food webs. Our results showed that squids occupy a large range of trophic levels in marine food webs and show a large trophic width, reflecting the versatility in their feeding behaviors and dietary habits. Models illustrated that squids are abundant organisms in marine ecosystems, and have high growth and consumption rates, but these parameters are highly variable because squids are adapted to a large variety of environmental conditions. Results also show that squids can have a large trophic impact on other elements of the food web, and top-down control from squids to their prey can be high. In addition, some squid species are important prey of apical predators and may be keystone species in marine food webs. In fact, we found strong interrelationships between neritic squids and the populations of their prey and predators in coastal and shelf areas, while the role of squids in open ocean and upwelling ecosystems appeared more constrained to a bottom-up impact on their predators. Therefore, large removals of squids will likely have large-scale effects on marine ecosystems. In addition, simulations confirm that squids are able to benefit from a general increase in fishing pressure, mainly due to predation release, and quickly respond to changes triggered by the environment. Squids may thus be very sensitive to the effects of fishing and climate change.

Performance of Large Format Transition Edge Sensor Microcalorimeter Arrays

NASA Technical Reports Server (NTRS)

Chervenak, J. A.; Adams, J. A.; Bandler, S. B.; Busch, S. E.; Eckart, M. E.; Ewin, A. E.; Finkbeiner, F. M.; Kilbourne, C. A.; Kelley, R. L.; Porst, J. P.;

Magnetic susceptibility characterisation of superparamagnetic microspheres

NASA Astrophysics Data System (ADS)

Grob, David Tim; Wise, Naomi; Oduwole, Olayinka; Sheard, Steve

2018-04-01

The separation of magnetic materials in microsystems using magnetophoresis has increased in popularity. The wide variety and availability of magnetic beads has fuelled this drive. It is important to know the magnetic characteristics of the microspheres in order to accurately use them in separation processes integrated on a lab-on-a-chip device. To investigate the magnetic susceptibility of magnetic microspheres, the magnetic responsiveness of three types of Dynabeads microspheres were tested using two different approaches. The magnetophoretic mobility of individual microspheres is studied using a particle tracking system and the magnetization of each type of Dynabeads microsphere is measured using SQUID relaxometry. The magnetic beads' susceptibility is obtained at four different applied magnetic fields in the range of 38-70 mT for both the mobility and SQUID measurements. The susceptibility values in both approaches show a consistent magnetic field dependence.

Variable temperature superconducting microscope

NASA Astrophysics Data System (ADS)

Cheng, Bo; Yeh, W. J.

2000-03-01

We have developed and tested a promising type of superconducting quantum interference device (SQUID) microscope, which can be used to detect vortex motion and can operate in magnetic fields over a large temperature range. The system utilizes a single-loop coupling transformer, consisting of a patterned high Tc superconducting thin film. At one end of the transformer, a 20 μm diam detecting loop is placed close to the sample. At the other end, a large loop is coupled to a NbTi coil, which is connected to a low Tc SQUID sensor. Transformers in a variety of sizes have been tested and calibrated. The results show that the system is capable of detecting the motion of a single vortex. We have used the microscope to study the behavior of moving vortices at various positions in a YBa2Cu3O7 thin film bridge.

Compact and Easy-Operation Magnetocardiograph With Four-Channel Planar Gradiometers

DTIC Science & Technology

2001-10-25

AND EASY-OPERATION MAGNETOCARDIOGRAPH WITH FOUR-CHANNEL PLANAR GRADIOMETERS K. Yokosawa1, D. Suzuki1, A. Tsukamoto2, T . Miyashita1, A. Kandori1, K...gradient direction was selected by rotating each rod individually. The QRS-complex and T -wave were traced clearly. The peak-to-peak noise, nB p-p, is...outside (b) the shielding cylinder. The environmental noise is also shown (c). M ag ne tic fi el d no is e (p T / H z 1/ 2 ) 80 fT/Hz1/2 Proceedings

Development of transition edge sensors with rf-SQUID based multiplexing system for the HOLMES experiment

NASA Astrophysics Data System (ADS)

Puiu, A.; Becker, D.; Bennett, D.; Faverzani, M.; Ferri, E.; Fowler, J.; Gard, J.; Hays-Wehle, J.; Hilton, G.; Giachero, A.; Maino, M.; Mates, J.; Nucciotti, A.; Schmidt, D.; Swetz, D.; Ullom, J.; Vale, L.

2017-09-01

Measuring the neutrino mass is one the most compelling issue in particle physics. HOLMES is an experiment funded by the European Research Council for a direct measurement of neutrino mass. HOLMES will perform a precise measurement of the end point of the Electron Capture decay spectrum of 163Ho in order to extract information on neutrino mass with a sensitivity as low as 1 eV. HOLMES, in its final configuration will deploy a 1000 pixel array of low temperature microcalorimeters: each calorimeter consists of an absorber, where the Ho atoms will be implanted, coupled to a Transition Edge Sensor thermometer. The detectors will be kept at the working temperature of ˜70 mK using a dilution refrigerator. In order to gather the required 3 × 1013 events in a three year long data taking with a pile up fraction as low as 10-4, detectors must fulfill rather high speed and resolution requirements, i.e. 10 µs rise time and 4 eV resolution. To ensure such performances with an efficient read out technique for very large detectors array kept at low temperature inside a cryostat is no trivial matter: at the moment, the most appealing read out technique applicable to large arrays of Transition Edge Sensors is rf-SQUID multiplexing. It is based on the use of rf-SQUIDs as input devices with flux ramp modulation for linearisation purposes; the rf-SQUID is then coupled to a super-conductive λ/4-wave resonator in the GHz range, and the modulated signal is finally read out using the homodyne technique.

Digitally controlled high-performance dc SQUID readout electronics for a 304-channel vector magnetometer

NASA Astrophysics Data System (ADS)

Bechstein, S.; Petsche, F.; Scheiner, M.; Drung, D.; Thiel, F.; Schnabel, A.; Schurig, Th

2006-06-01

Recently, we have developed a family of dc superconducting quantum interference device (SQUID) readout electronics for several applications. These electronics comprise a low-noise preamplifier followed by an integrator, and an analog SQUID bias circuit. A highly-compact low-power version with a flux-locked loop bandwidth of 0.3 MHz and a white noise level of 1 nV/√Hz was specially designed for a 304-channel low-Tc dc SQUID vector magnetometer, intended to operate in the new Berlin Magnetically Shielded Room (BMSR-2). In order to minimize the space needed to mount the electronics on top of the dewar and to minimize the power consumption, we have integrated four electronics channels on one 3 cm × 10 cm sized board. Furthermore we embedded the analog components of these four channels into a digitally controlled system including an in-system programmable microcontroller. Four of these integrated boards were combined to one module with a size of 4 cm × 4 cm × 16 cm. 19 of these modules were implemented, resulting in a total power consumption of about 61 W. To initialize the 304 channels and to service the system we have developed software tools running on a laptop computer. By means of these software tools the microcontrollers are fed with all required data such as the working points, the characteristic parameters of the sensors (noise, voltage swing), or the sensor position inside of the vector magnetometer system. In this paper, the developed electronics including the software tools are described, and first results are presented.

Structure and magnetic properties of SiO{sub 2}/PCL novel sol–gel organic–inorganic hybrid materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Catauro, Michelina, E-mail: michelina.catauro@unina2.it; Bollino, Flavia; Cristina Mozzati, Maria

2013-07-15

Organic–inorganic nanocomposite materials have been synthesized via sol–gel. They consist of an inorganic SiO{sub 2} matrix, in which different percentages of poly(ε-caprolactone) (PCL) have been incorporated. The formation of H-bonds among the carbonyl groups of the polymer chains and Si–OH group of the inorganic matrix has been proved by means of Fourier transform infrared spectroscopy (FT-IR) analysis and has been confirmed by solid-state nuclear magnetic resonance (NMR). X-Ray diffraction (XRD) analysis highlighted the amorphous nature of the synthesized materials. Scanning electron microscope (SEM) micrograph and atomic force microscope (AFM) topography showed their homogeneous morphology and nanostructure nature. Considering the opportunitymore » to synthesize these hybrid materials under microgravity conditions by means of magnetic levitation, superconducting quantum interference device (SQUID) magnetometry has been used to quantify their magnetic susceptibility. This measure has shown that the SiO{sub 2}/PCL hybrid materials are diamagnetic and that their diamagnetic susceptibility is independent of temperature and increases with the PCL amount. - Graphical abstract: Characterization and magnetic properties of SiO{sub 2}/PCL organic–inorganic hybrid materials synthesized via sol–gel. FT-IR, Fourier transform infrared spectroscopy; solid-state NMR: solid-state nuclear magnetic resonance; SQUID: superconducting quantum interference device. - Highlights: • Sol–gel synthesis of SiO{sub 2}/PCL amorphous class I organic–inorganic hybrid materials. • FT-IR and NMR analyses show the hydrogen bonds formation between SiO{sub 2} and PCL. • AFM and SEM analyses confirm that the SiO{sub 2}/PCL are homogenous hybrid materials. • The SQUID measures show that the simples are diamagnetic. • Diamagnetic susceptibility of SiO{sub 2}/PCL materials increases with the PCL amount.« less

Be together, not the same: Spatiotemporal organization of different cilia types generates distinct transport functions

NASA Astrophysics Data System (ADS)

Nawroth, Janna; Guo, Hanliang; Ruby, Edward; Dabiri, John; McFall-Ngai, Margaret; Kanso, Eva

2016-11-01

Motile cilia are microscopic, hair-like structures on the cell surface that can sense and propel the extracellular fluid environment. Cilia are often thought to be limited to stereotypic morphologies, beat kinematics and non-discriminatory clearance functions, but we find that the spatiotemporal organization of different cilia types and beat behaviors can generate complex flow patterns and transport functions. Here, we present a case study in the Hawaiian bobtail squid where collective ciliary activity and resulting flow fields help recruit symbiont bacteria to the animal host. In particular, we demonstrate empirically and computationally how the squid's internal cilia act like a microfluidic device that actively filters the water for potential bacterial candidates and also provides a sheltered zone allowing for accumulation of mucus and bacteria into a biofilm. Moreover, in this sheltered zone, different cilia-driven flows enhance diffusion of biochemical signals, which could accelerate specific bacteria-host recognition. These results suggest that studying cilia activity on the population level might reveal a diverse range of biological transport and sensing functions. Moreover, understanding cilia as functional building blocks could inspire the design of ciliated robots and devices.

Atom interferometric gravity gradiometer: Disturbance compensation and mobile gradiometry

NASA Astrophysics Data System (ADS)

Mahadeswaraswamy, Chetan

First ever mobile gravity gradient measurement based on Atom Interferometric sensors has been demonstrated. Mobile gravity gradiometers play a significant role in high accuracy inertial navigation systems in order to distinguish inertial acceleration and acceleration due to gravity. The gravity gradiometer consists of two atom interferometric accelerometers. In each of the accelerometer an ensemble of laser cooled Cesium atoms is dropped and using counter propagating Raman pulses (pi/2-pi-pi/2) the ensemble is split into two states for carrying out atom interferometry. The interferometer phase is proportional to the specific force experienced by the atoms which is a combination of inertial acceleration and acceleration due to gravity. The difference in phase between the two atom interferometric sensors is proportional to gravity gradient if the platform does not undergo any rotational motion. However, any rotational motion of the platform induces spurious gravity gradient measurements. This apparent gravity gradient due to platform rotation is considerably different for an atom interferometric sensor compared to a conventional force rebalance type sensor. The atoms are in free fall and are not influenced by the motion of the case except at the instants of Raman pulses. A model for determining apparent gravity gradient due to rotation of platform was developed and experimentally verified for different frequencies. This transfer function measurement also lead to the development of a new technique for aligning the Raman laser beams with the atom clusters to within 20 mu rad. This gravity gradiometer is situated in a truck for the purpose of undertaking mobile surveys. A disturbance compensation system was designed and built in order to compensate for the rotational disturbances experienced on the floor of a truck. An electric drive system was also designed specifically to be able to move the truck in a uniform motion at very low speeds of about 1cm/s. A 250 x10-9 s-2 gravity gradient signature due to an underground void at Hansen Experimental Physics Building at Stanford was successfully measured using this mobile gradiometer.

Hybrid gravity survey to search for submarine ore deposit

NASA Astrophysics Data System (ADS)

Araya, A.; Kanazawa, T.; Fujimoto, H.; Shinohara, M.; Yamada, T.; Mochizuki, K.; Iizasa, K.; Ishihara, T.; Omika, S.

2011-12-01

Along with seismic surveys, gravity survey is a useful method to profile the underground density structure. We propose a hybrid gravity survey using gravimeters and gravity gradiometers to detect submarine ore deposits as density anomalies by towing the instruments using an AUV (Autonomous Underwater Vehicle) or an ROV (Remotely Operated Vehicle). Gravimeters measure the regional density structure below the seafloor, whereas gravity gradiometers are sensitive to localized mass distribution. A gravity gradiometer comprises two accelerometers arranged with a vertical separation, and a gravity gradient can be obtained from the acceleration difference. Compared to gravimeters, gravity gradiometers are insensitive to common disturbances such as parallel acceleration, thermal drift, and apparent gravity effect (Eötvös effect). We made two accelerometers using astatic pendulums, and obtained common acceleration reduction more than two orders of magnitude. With these pendulums of 500-mm separation, resolution of 7E (=7x10^{-9}(1/s^2)), enough to detect a typical ore deposit buried 50m below the seafloor, was evaluated. During measurements using a submersible mobile object, instrument orientation is required to be controlled to keep verticality and to reduce centrifugal force associated with rotation of the instrument. Using a gyro and a tiltmeter, angular rotation was shown to be controlled within 0.001deg/s which corresponds to 0.3E in effective gravity gradient due to the centrifugal force. In this paper, target of this research, details of the instruments and their performance, and development for the submarine gravity survey using an AUV will be presented.

Development of a rotating gravity gradiometer for earth orbit applications (AAFE)

NASA Technical Reports Server (NTRS)

Forward, R. L.; Bell, C. C.; Lahue, P. M.; Mallove, E. F.; Rouse, D. W.

1973-01-01

Some preliminary mission studies are described along with the design, fabrication, and test of a breadboard model of an earth orbital, rotating gravity gradiometer with a design goal of 10 to the minus 11th power/sec sq (0.01 EU) in a 35-sec integration time. The proposed mission uses a Scout vehicle to launch one (or two orthogonally oriented) spin-stabilized satellites into a 330-km circular polar orbit some 20 days before an equinox. During the short orbital lifetime, the experiment would obtain two complete maps of the gravity gradient field with a resolution approaching 270 km (degree 75). The breadboard model of the gradiometer demonstrated a combined thermal and electronic noise threshold of 0.015 EU per data channel. The design changes needed to reduce the noise to less than 0.01 EU were identified. Variations of the sensor output signal with temperature were experimentally determined and a suitable method of temperature compensation was developed and tested. Other possible error sources, such as sensor interaction with satellite dynamics and magnetic fields, were studied analytically and shown to be small.

Optimized Geometry for Superconducting Sensing Coils

NASA Technical Reports Server (NTRS)

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

2008-01-01

An optimized geometry has been proposed for superconducting sensing coils that are used in conjunction with superconducting quantum interference devices (SQUIDs) in magnetic resonance imaging (MRI), magnetoencephalography (MEG), and related applications in which magnetic fields of small dipoles are detected. In designing a coil of this type, as in designing other sensing coils, one seeks to maximize the sensitivity of the detector of which the coil is a part, subject to geometric constraints arising from the proximity of other required equipment. In MRI or MEG, the main benefit of maximizing the sensitivity would be to enable minimization of measurement time. In general, to maximize the sensitivity of a detector based on a sensing coil coupled with a SQUID sensor, it is necessary to maximize the magnetic flux enclosed by the sensing coil while minimizing the self-inductance of this coil. Simply making the coil larger may increase its self-inductance and does not necessarily increase sensitivity because it also effectively increases the distance from the sample that contains the source of the signal that one seeks to detect. Additional constraints on the size and shape of the coil and on the distance from the sample arise from the fact that the sample is at room temperature but the coil and the SQUID sensor must be enclosed within a cryogenic shield to maintain superconductivity.

Lowering effect of firefly squid powder on triacylglycerol content and glucose-6-phosphate dehydrogenase activity in rat liver.

PubMed

Takeuchi, Hiroyuki; Morita, Ritsuko; Shirai, Yoko; Nakagawa, Yoshihisa; Terashima, Teruya; Ushikubo, Shun; Matsuo, Tatsuhiro

2014-01-01

Effects of dietary firefly squid on serum and liver lipid levels were investigated. Male Wistar rats were fed a diet containing 5% freeze-dried firefly squid or Japanese flying squid for 2 weeks. There was no significant difference in the liver triacylglycerol level between the control and Japanese flying squid groups, but the rats fed the firefly squid diet had a significantly lower liver triacylglycerol content than those fed the control diet. No significant difference was observed in serum triacylglycerol levels between the control and firefly squid groups. The rats fed the firefly squid had a significantly lower activity of liver glucose-6-phosphate dehydrogenase compared to the rats fed the control diet. There was no significant difference in liver fatty acid synthetase activity among the three groups. Hepatic gene expression and lipogenic enzyme activity were investigated; a DNA microarray showed that the significantly enriched gene ontology category of down-regulated genes in the firefly squid group was "lipid metabolic process". The firefly squid group had lower mRNA level of glucose-6-phosphate dehydrogenase compared to the controls. These results suggest that an intake of firefly squid decreases hepatic triacylglycerol in rats, and the reduction of mRNA level and enzyme activity of glucose-6-phosphate dehydrogenase might be related to the mechanisms.

Spaceborne gravity gradiometry characterizing the data type

NASA Technical Reports Server (NTRS)

Sonnabend, D.

1987-01-01

Satellite gravity gradiometers, particularly the two stage drag free carrier vehicle are discussed. An inner stage, carrying the tracking antenna(s), measures the relative position of the internal free proof mass, and feeds this to a set of magnetic forcers, acting against the outer or main vehicle. As the external forces on the inner stage are low, and as the position relative to the proof mass is tightly controlled, carrier phase disturbances are greatly reduced. The arrangement lowers instantaneous accelerations. It is stressed that gravity gradiometers do not measure gradients, they measure components of an intrinsic tensor.

Earth's gravity field mapping requirements and concept. [using a supercooled gravity gradiometer

NASA Technical Reports Server (NTRS)

Vonbun, F. O.; Kahn, W. D.

1981-01-01

A future sensor is considered for mapping the Earth's gravity field to meet future scientific and practical requirements for earth and oceanic dynamics. These are approximately + or - 0.1 to 10 mgal over a block size of about 50 km and over land and an ocean geoid to 1 to 2 cm over a distance of about 50 km. To achieve these values requires a gravity gradiometer with a sensitivity of approximately 10 to the -4 power EU in a circular polar orbiting spacecraft with an orbital altitude ranging 160 km to 180 km.

Analysing magnetism using scanning SQUID microscopy.

PubMed

Reith, P; Renshaw Wang, X; Hilgenkamp, H

2017-12-01

Scanning superconducting quantum interference device microscopy (SSM) is a scanning probe technique that images local magnetic flux, which allows for mapping of magnetic fields with high field and spatial accuracy. Many studies involving SSM have been published in the last few decades, using SSM to make qualitative statements about magnetism. However, quantitative analysis using SSM has received less attention. In this work, we discuss several aspects of interpreting SSM images and methods to improve quantitative analysis. First, we analyse the spatial resolution and how it depends on several factors. Second, we discuss the analysis of SSM scans and the information obtained from the SSM data. Using simulations, we show how signals evolve as a function of changing scan height, SQUID loop size, magnetization strength, and orientation. We also investigated 2-dimensional autocorrelation analysis to extract information about the size, shape, and symmetry of magnetic features. Finally, we provide an outlook on possible future applications and improvements.

Analysing magnetism using scanning SQUID microscopy

NASA Astrophysics Data System (ADS)

Reith, P.; Renshaw Wang, X.; Hilgenkamp, H.

2017-12-01

Scanning superconducting quantum interference device microscopy (SSM) is a scanning probe technique that images local magnetic flux, which allows for mapping of magnetic fields with high field and spatial accuracy. Many studies involving SSM have been published in the last few decades, using SSM to make qualitative statements about magnetism. However, quantitative analysis using SSM has received less attention. In this work, we discuss several aspects of interpreting SSM images and methods to improve quantitative analysis. First, we analyse the spatial resolution and how it depends on several factors. Second, we discuss the analysis of SSM scans and the information obtained from the SSM data. Using simulations, we show how signals evolve as a function of changing scan height, SQUID loop size, magnetization strength, and orientation. We also investigated 2-dimensional autocorrelation analysis to extract information about the size, shape, and symmetry of magnetic features. Finally, we provide an outlook on possible future applications and improvements.

Development of a vector-tensor system to measure the absolute magnetic flux density and its gradient in magnetically shielded rooms.

PubMed

Voigt, J; Knappe-Grüneberg, S; Gutkelch, D; Haueisen, J; Neuber, S; Schnabel, A; Burghoff, M

2015-05-01

Several experiments in fundamental physics demand an environment of very low, homogeneous, and stable magnetic fields. For the magnetic characterization of such environments, we present a portable SQUID system that measures the absolute magnetic flux density vector and the gradient tensor. This vector-tensor system contains 13 integrated low-critical temperature (LTc) superconducting quantum interference devices (SQUIDs) inside a small cylindrical liquid helium Dewar with a height of 31 cm and 37 cm in diameter. The achievable resolution depends on the flux density of the field under investigation and its temporal drift. Inside a seven-layer mu-metal shield, an accuracy better than ±23 pT for the components of the static magnetic field vector and ±2 pT/cm for each of the nine components of the gradient tensor is reached by using the shifting method.

Development of a vector-tensor system to measure the absolute magnetic flux density and its gradient in magnetically shielded rooms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Voigt, J.; Knappe-Grüneberg, S.; Gutkelch, D.

2015-05-15

Several experiments in fundamental physics demand an environment of very low, homogeneous, and stable magnetic fields. For the magnetic characterization of such environments, we present a portable SQUID system that measures the absolute magnetic flux density vector and the gradient tensor. This vector-tensor system contains 13 integrated low-critical temperature (LTc) superconducting quantum interference devices (SQUIDs) inside a small cylindrical liquid helium Dewar with a height of 31 cm and 37 cm in diameter. The achievable resolution depends on the flux density of the field under investigation and its temporal drift. Inside a seven-layer mu-metal shield, an accuracy better than ±23more » pT for the components of the static magnetic field vector and ±2 pT/cm for each of the nine components of the gradient tensor is reached by using the shifting method.« less

XANES study of Fe-implanted strontium titanate

NASA Astrophysics Data System (ADS)

Lobacheva, O.; Goncharova, L. V.; Chavarha, M.; Sham, T. K.

2014-03-01

Properties of strontium titanate SrTiO3 (STO) depend to a great extent on the substitutional dopants and defects of crystal structure. The ion beam implantation method was used for doping STO (001) crystals with Fe at different doses. Implanted samples were then annealed at 350°C in oxygen to induce recrystallization and remove oxygen vacancies produced during ion implantation process. The effect of Fe doping and post-implantation annealing was studied by X-ray Absorption Near Edge Spectroscopy (XANES) method and Superconducting Quantum Interference Device (SQUID). XANES allowed to monitor the change in structure of STO crystals and in the local environment of Fe following the implantation and annealing steps. SQUID measurements revealed correlation between magnetic moment and Fe implantation dose. Ferromagnetic hysteresis was observed on selected Fe-implanted STO at 5 K. The observed magnetic properties can be correlated with the several Fe oxide phases in addition to the presence of O/Ti vacancies.

Magnetic resonance force microscopy of paramagnetic electron spins at millikelvin temperatures.

PubMed

Vinante, A; Wijts, G; Usenko, O; Schinkelshoek, L; Oosterkamp, T H

2011-12-06

Magnetic resonance force microscopy (MRFM) is a powerful technique to detect a small number of spins that relies on force detection by an ultrasoft magnetically tipped cantilever and selective magnetic resonance manipulation of the spins. MRFM would greatly benefit from ultralow temperature operation, because of lower thermomechanical noise and increased thermal spin polarization. Here we demonstrate MRFM operation at temperatures as low as 30 mK, thanks to a recently developed superconducting quantum interference device (SQUID)-based cantilever detection technique, which avoids cantilever overheating. In our experiment, we detect dangling bond paramagnetic centres on a silicon surface down to millikelvin temperatures. Fluctuations of such defects are supposedly linked to 1/f magnetic noise and decoherence in SQUIDs, as well as in several superconducting and single spin qubits. We find evidence that spin diffusion has a key role in the low-temperature spin dynamics.

Quantum state transfer and controlled-phase gate on one-dimensional superconducting resonators assisted by a quantum bus.

PubMed

Hua, Ming; Tao, Ming-Jie; Deng, Fu-Guo

2016-02-24

We propose a quantum processor for the scalable quantum computation on microwave photons in distant one-dimensional superconducting resonators. It is composed of a common resonator R acting as a quantum bus and some distant resonators rj coupled to the bus in different positions assisted by superconducting quantum interferometer devices (SQUID), different from previous processors. R is coupled to one transmon qutrit, and the coupling strengths between rj and R can be fully tuned by the external flux through the SQUID. To show the processor can be used to achieve universal quantum computation effectively, we present a scheme to complete the high-fidelity quantum state transfer between two distant microwave-photon resonators and another one for the high-fidelity controlled-phase gate on them. By using the technique for catching and releasing the microwave photons from resonators, our processor may play an important role in quantum communication as well.

Local tuning of the order parameter in superconducting weak links: A zero-inductance nanodevice

NASA Astrophysics Data System (ADS)

Winik, Roni; Holzman, Itamar; Dalla Torre, Emanuele G.; Buks, Eyal; Ivry, Yachin

2018-03-01

Controlling both the amplitude and the phase of the superconducting quantum order parameter (" separators="|ψ ) in nanostructures is important for next-generation information and communication technologies. The lack of electric resistance in superconductors, which may be advantageous for some technologies, hinders convenient voltage-bias tuning and hence limits the tunability of ψ at the microscopic scale. Here, we demonstrate the local tunability of the phase and amplitude of ψ, obtained by patterning with a single lithography step a Nb nano-superconducting quantum interference device (nano-SQUID) that is biased at its nanobridges. We accompany our experimental results by a semi-classical linearized model that is valid for generic nano-SQUIDs with multiple ports and helps simplify the modelling of non-linear couplings among the Josephson junctions. Our design helped us reveal unusual electric characteristics with effective zero inductance, which is promising for nanoscale magnetic sensing and quantum technologies.

Low-frequency nondestructive analysis of cracks in multilayer structures using a scanning magnetic microscope

NASA Astrophysics Data System (ADS)

Adamo, M.; Nappi, C.; Sarnelli, E.

2010-09-01

The use of a scanning magnetic microscope (SMM) with a high temperature superconducting quantum interference device (SQUID) for quantitative measurements in eddy current nondestructive analysis (NDA) is presented. The SQUID has been used to detect the weak magnetic field variations around a small defect, close to a structural part generating an intensive magnetic field. The experimental data for a deep crack close to a rivet in a multilayer conducting plate have been taken in a RF-shielded environment and discussed in the light of the theoretical predictions. The results show that eddy current NDA can distinguish subsurface crack signals from wider structural signals, with defects located 10 mm below the surface. Moreover, in order to visualize the structure of the probing current when a circular induction coil is used, the simulation of eddy currents in a thick unflawed conducting plate has been carried out.

Properties of Josephson Junction Fabricated on Bicrystal Substrate with Different Misorientation Angles

NASA Astrophysics Data System (ADS)

Minotani, Tadashi; Kawakami, Satoru; Kuroki, Yukinori; Enpuku, Keiji

1998-06-01

In order to develop YBa2Cu3O7-δ bicrystal junctions suitable for high-performance superconducting quantum interference device (SQUID), the relationship between the junction properties and the misorientation angle of the bicrystal substrate is studied experimentally. Misorientation angles of 24°, 27°, 30°, 33° and 36.8° are used, and the angular dependencies of junction resistance Rs and critical current Io are investigated. It is shown that values of Rs and Io approximately follow the relation IoRs1.5=const. in these junctions. The obtained results are analyzed in terms of the direct and resonant tunneling mechanisms. It is also shown that values of Rs≈10 Ω and Io≈20 µA can be obtained rather reproducibly when we use the 30° junctions. The properties of this junction are very promising for the development of high-performance SQUID.

Iron overload in patients receiving allogeneic hematopoietic stem cell transplantation: quantification of iron burden by a superconducting quantum interference device (SQUID) and therapeutic effectiveness of phlebotomy.

PubMed

Busca, Alessandro; Falda, Michele; Manzini, Paola; D'Antico, Sergio; Valfrè, Adriano; Locatelli, Franco; Calabrese, Roberto; Chiappella, Annalisa; D'Ardia, Stefano; Longo, Filomena; Piga, Antonio

2010-01-01

Iron overload (IO) is a known adverse prognostic factor in patients who undergo allogeneic hematopoietic stem cell transplantation (HSCT) for thalassemia and appears to play a similar role in patients with other hematologic disorders. The estimation of IO is based primarily on serum ferritin level; however, many confounding factors can result in ferritin overestimation, especially in HSCT recipients. The aim of the present study was to quantify IO after HSCT using a superconducting quantum interference device (SQUID), and to evaluate the impact of IO on hepatic function and infections. In addition, the feasibility of iron depletion was investigated. A total of 102 consecutive allogeneic HSCT recipients admitted to our outpatient department between December 2005, and December 2007, were analyzed. Primary diagnosis included acute leukemia/myelodysplastic syndrome in 61% of cases. Assessment of IO after HSCT included serum ferritin; in those with hyperferritinemia (ferritin>1000 ng/mL), liver iron concentration (LIC) was evaluated by SQUID magnetic susceptometry. Iron removal therapy was offered to patients with moderate IO (LIC 1000-2000 microg Fe/g wet weight [ww]) or severe IO (LIC >2,000 microg Fe/g ww). Fifty-seven patients had a ferritin level <1000 ng/mL: the median time between HSCT and assessment of ferritin level was 1006 days (range, 93-5239 days), significantly different from the median time of 183 days (range, 78-2957 days) in the 45 patients with a ferritin level >1000 ng/mL. Out of 42 patients evaluated by SQUID, 29 had moderate to severe IO (median LIC value, 1493 microg Fe/g ww [range, 1030-3253]). In a multivariate analysis, a significant correlation was found between a ferritin level >1000 ng/mL and the presence of at least one abnormal liver function test (LFT) ORo=6.8; 95% CI=2.2-20.6). In addition, the rate of proven/probable invasive fungal disease was significantly higher in the patients with hyperferritinemia (13% vs 0%; P=.006). Nineteen of the 24 patients considered eligible for iron-depletion therapy underwent regular phlebotomy; 13 completed the program in a median of 287 days (range, 92-779 days), reaching the target of a ferritin level<500 ng/mL; LIC was significantly reduced (median, 1419 microg Fe/g ww to 625 microg Fe/g ww; P < .001) in 8 of the 9 patients who were revaluated by SQUID at the end of the iron-depletion program. In conclusion, the measurement of LIC obtained by SQUID documented the presence of moderate/severe IO in 69% of the patients with a high ferritin level. Our data showed that in HSCT recipients, high ferritin level is an independent risk factor for abnormal LFTs, and IO may be considered a potential risk factor for fungal infections. A phlebotomy program may be feasible in two-thirds of the patients who might benefit from iron depletion. Copyright (c) 2010 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.

High-resolution photon spectroscopy with a microwave-multiplexed 4-pixel transition edge sensor array

NASA Astrophysics Data System (ADS)

Guss, Paul; Rabin, Michael; Croce, Mark; Hoteling, Nathan; Schwellenbach, David; Kruschwitz, Craig; Mocko, Veronika; Mukhopadhyay, Sanjoy

2017-09-01

We demonstrate very high-resolution photon spectroscopy with a microwave-multiplexed 4-pixel transition edge sensor (TES) array. The readout circuit consists of superconducting microwave resonators coupled to radio frequency superconducting-quantum-interference devices (RF-SQUIDs) and transduces changes in input current to changes in phase of a microwave signal. We used a flux-ramp modulation to linearize the response and avoid low-frequency noise. The result is a very high-resolution photon spectroscopy with a microwave-multiplexed 4-pixel transition edge sensor array. We performed and validated a small-scale demonstration and test of all the components of our concept system, which encompassed microcalorimetry, microwave multiplexing, RF-SQUIDs, and software-defined radio (SDR). We shall display data we acquired in the first simultaneous combination of all key innovations in a 4-pixel demonstration, including microcalorimetry, microwave multiplexing, RF-SQUIDs, and SDR. We present the energy spectrum of a gadolinium-153 (153Gd) source we measured using our 4-pixel TES array and the RF-SQUID multiplexer. For each pixel, one can observe the two 97.4 and 103.2 keV photopeaks. We measured the 153Gd photon source with an achieved energy resolution of 70 eV, full width half maximum (FWHM) at 100 keV, and an equivalent readout system noise of 90 pA/pHz at the TES. This demonstration establishes a path for the readout of cryogenic x-ray and gamma ray sensor arrays with more elements and spectral resolving powers. We believe this project has improved capabilities and substantively advanced the science useful for missions such as nuclear forensics, emergency response, and treaty verification through the explored TES developments.

Flux trapping in multi-loop SQUIDs and its impact on SQUID-based absolute magnetometry

NASA Astrophysics Data System (ADS)

Schönau, T.; Zakosarenko, V.; Schmelz, M.; Anders, S.; Meyer, H.-G.; Stolz, R.

2018-07-01

The effect of flux trapping on the flux-voltage characteristics of multi-loop SQUID magnetometers was investigated by means of repeated cool-down cycles in a stepwise increased magnetic background field. For a SQUID with N parallel loops, N different flux offsets, each separated by {{{Φ }}}0/N, were observed even in zero magnetic field. These flux offsets further split into a so called fine structure, which can be explained by minor asymmetries in the SQUID design. The observed results are discussed with particular regard to their impact on the previously presented absolute SQUID cascade vector magnetometer.

Controlled and in situ target strengths of the jumbo squid Dosidicus gigas and identification of potential acoustic scattering sources.

PubMed

Benoit-Bird, Kelly J; Gilly, William F; Au, Whitlow W L; Mate, Bruce

2008-03-01

This study presents the first target strength measurements of Dosidicus gigas, a large squid that is a key predator, a significant prey, and the target of an important fishery. Target strength of live, tethered squid was related to mantle length with values standardized to the length squared of -62.0, -67.4, -67.9, and -67.6 dB at 38, 70, 120, and 200 kHz, respectively. There were relatively small differences in target strength between dorsal and anterior aspects and none between live and freshly dead squid. Potential scattering mechanisms in squid have been long debated. Here, the reproductive organs had little effect on squid target strength. These data support the hypothesis that the pen may be an important source of squid acoustic scattering. The beak, eyes, and arms, probably via the sucker rings, also play a role in acoustic scattering though their effects were small and frequency specific. An unexpected source of scattering was the cranium of the squid which provided a target strength nearly as high as that of the entire squid though the mechanism remains unclear. Our in situ measurements of the target strength of free-swimming squid support the use of the values presented here in D. gigas assessment studies.

Effects of thermal processing and various chemical substances on formaldehyde and dimethylamine formation in squid Dosidicus gigas.

PubMed

Zhu, Junli; Li, Jianrong; Jia, Jia

2012-09-01

Trimethylamine oxide (TMAO) in squid is demethylated to dimethylamine (DMA) and formaldehyde (FA) during storage and processing. This study examined the effects of thermal processing and various chemical substances on FA and DMA formation in squid. The thermal conversion of TMAO was assessed by analysing four squid and four gadoid fish species, which revealed that FA, DMA and trimethylamine (TMA) were gradually produced in squid, whereas TMA increased and FA decreased in gadoid fish. A significant increase in both FA and DMA levels was observed in the supernatant of jumbo squid with increased heating temperature and extended heating time at pH 6-7. Ferrous chloride combined with cysteine and/or ascorbate had a significantly positive effect on FA formation in the heated supernatant of jumbo squid. No significant difference was observed in the levels of Cu and Fe in squid and gadoid fish. The capability of Fe(2+) to promote the formation of FA and DMA was not completely attributable to its reducing power in squid. Non-enzymatic decomposition of TMAO was a key pathway during the thermal processing of jumbo squid, and Fe(2+) was a crucial activator in the formation of FA and DMA. Copyright © 2012 Society of Chemical Industry.

Scanning SQUID Microscope and its Application in Detecting Weak Currents

NASA Astrophysics Data System (ADS)

Zhong, Chaorong; Li, Fei; Zhang, Fenghui; Ding, Hongsheng; Luo, Sheng; Lin, Dehua; He, Yusheng

A scanning SQUID microscope based on HTS dc SQUID has been developed. One of the applications of this microscope is to detect weak currents inside the sample. Considering that what being detected by the SQUID is the vertical component of the magnetic field on a plan where the SQUID lies, whereas the current which produces the magnetic field is actually located in a plan below the SQUID, a TWO PLAN model has been established. In this model Biot-Savart force laws and Fourier transformation were used to inverse the detected magnetic field into the underneath weak current. It has been shown that the distance between the current and the SQUID and the noise ratio of the experimental data have significant effects on the quality of the inverse process.

Identifying Pelagic Habitat Hotspots of Neon Flying Squid in the Temperate Waters of the Central North Pacific.

PubMed

Alabia, Irene D; Saitoh, Sei-Ichi; Mugo, Robinson; Igarashi, Hiromichi; Ishikawa, Yoichi; Usui, Norihisa; Kamachi, Masafumi; Awaji, Toshiyuki; Seito, Masaki

2015-01-01

We identified the pelagic habitat hotspots of the neon flying squid (Ommastrephes bartramii) in the central North Pacific from May to July and characterized the spatial patterns of squid aggregations in relation to oceanographic features such as mesoscale oceanic eddies and the Transition Zone Chlorophyll-a Front (TZCF). The data used for the habitat model construction and analyses were squid fishery information, remotely-sensed and numerical model-derived environmental data from May to July 1999-2010. Squid habitat hotspots were deduced from the monthly Maximum Entropy (MaxEnt) models and were identified as regions of persistent high suitable habitat across the 12-year period. The distribution of predicted squid habitat hotspots in central North Pacific revealed interesting spatial and temporal patterns likely linked with the presence and dynamics of oceanographic features in squid's putative foraging grounds from late spring to summer. From May to June, the inferred patches of squid habitat hotspots developed within the Kuroshio-Oyashio transition zone (KOTZ; 37-40°N) and further expanded north towards the subarctic frontal zone (SAFZ; 40-44°N) in July. The squid habitat hotspots within the KOTZ and areas west of the dateline (160°W-180°) were likely influenced and associated with the highly dynamic and transient oceanic eddies and could possibly account for lower squid suitable habitat persistence obtained from these regions. However, predicted squid habitat hotspots located in regions east of the dateline (180°-160°W) from June to July, showed predominantly higher squid habitat persistence presumably due to their proximity to the mean position of the seasonally-shifting TZCF and consequent utilization of the highly productive waters of the SAFZ.

Design of Cryocoolers for Microwatt Superconducting Devices

NASA Technical Reports Server (NTRS)

Zimmerman, J. E.

1985-01-01

The primary applications of the cryocoolers are for cooling various Josephson devices such as SQUID magnetometers and amplifiers, voltage standards, and microwave mixers and detectors. The common feature of these devices is their extremely low inherent bias power requirement, of the order of 10/1 W per junction. This provides the possibility of designing compact, low-power cryocoolers for these applications. Several concepts were explored and a number of laboratory model cryocoolers were built. These include low-power nonmagnetic regenerative machines of the Stirling or Gifford-McMahon type, three or four-stage Joule-Thomson machines, liquid-helium dewars with integral small cryocoolers to reduce the evaporation rate, and liquid-helium dewars with integral continuously or intermittently operated small helium liquefiers to permit operation of cryogenic devices for indefinite time periods.

Allometry indicates giant eyes of giant squid are not exceptional.

PubMed

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

2013-02-18

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

Theory and application of high temperature superconducting eddy current probes for nondestructive evaluation

NASA Astrophysics Data System (ADS)

Claycomb, James Ronald

1998-10-01

Several High-T c Superconducting (HTS) eddy current probes have been developed for applications in electromagnetic nondestructive evaluation (NDE) of conducting materials. The probes utilize high-T c SUperconducting Quantum Interference Device (SQUID) magnetometers to detect the fields produced by the perturbation of induced eddy currents resulting from subsurface flaws. Localized HTS shields are incorporated to selectively screen out environmental electromagnetic interference and enable movement of the instrument in the Earth's magnetic field. High permeability magnetic shields are employed to focus flux into, and thereby increase the eddy current density in the metallic test samples. NDE test results are presented, in which machined flaws in aluminum alloy are detected by probes of different design. A novel current injection technique performing NDE of wires using SQUIDs is also discussed. The HTS and high permeability shields are designed based on analytical and numerical finite element method (FEM) calculations presented here. Superconducting and high permeability magnetic shields are modeled in uniform noise fields and in the presence of dipole fields characteristic of flaw signals. Several shield designs are characterized in terms of (1) their ability to screen out uniform background noise fields; (2) the resultant improvement in signal-to-noise ratio and (3) the extent to which dipole source fields are distorted. An analysis of eddy current induction is then presented for low frequency SQUID NDE. Analytical expressions are developed for the induced eddy currents and resulting magnetic fields produced by excitation sources above conducting plates of varying thickness. The expressions derived here are used to model the SQUID's response to material thinning. An analytical defect model is also developed, taking into account the attenuation of the defect field through the conducting material, as well as the current flow around the edges of the flaw. Time harmonic FEM calculations are then used to model the electromagnetic response of eight probe designs, consisting of an eddy current drive coil coupled to a SQUID surrounded by superconducting and/or high permeability magnetic shielding. Simulations are carried out with the eddy current probes located a finite distance above a conducting surface. Results are quantified in terms of shielding and focus factors for each probe design.

Impact of infrasound atmospheric noise on gravity detectors used for astrophysical and geophysical applications

NASA Astrophysics Data System (ADS)

Fiorucci, Donatella; Harms, Jan; Barsuglia, Matteo; Fiori, Irene; Paoletti, Federico

2018-03-01

Density changes in the atmosphere produce a fluctuating gravity field that affects gravity strainmeters or gravity gradiometers used for the detection of gravitational waves and for geophysical applications. This work addresses the impact of the atmospheric local gravity noise on such detectors, extending previous analyses. In particular we present the effect introduced by the building housing the detectors, and we analyze local gravity-noise suppression by constructing the detector underground. We present also new sound spectra and correlation measurements. The results obtained are important for the design of future gravitational-wave detectors and gravity gradiometers used to detect prompt gravity perturbations from earthquakes.

Optical multichannel room temperature magnetic field imaging system for clinical application

PubMed Central

Lembke, G.; Erné, S. N.; Nowak, H.; Menhorn, B.; Pasquarelli, A.

2014-01-01

Optically pumped magnetometers (OPM) are a very promising alternative to the superconducting quantum interference devices (SQUIDs) used nowadays for Magnetic Field Imaging (MFI), a new method of diagnosis based on the measurement of the magnetic field of the human heart. We present a first measurement combining a multichannel OPM-sensor with an existing MFI-system resulting in a fully functional room temperature MFI-system. PMID:24688820

Germanium Resistance Thermometer For Subkelvin Temperatures

NASA Technical Reports Server (NTRS)

Castles, Stephen H.

1993-01-01

Improved germanium resistance thermometer measures temperatures as small as 0.01 K accurately. Design provides large area for electrical connections (to reduce electrical gradients and increase sensitivity to changes in temperatures) and large heat sink (to minimize resistance heating). Gold pads on top and bottom of germanium crystal distribute electrical current and flow of heat nearly uniformly across crystal. Less expensive than magnetic thermometers or superconducting quantum interference devices (SQUID's) otherwise used.

New technologies for the detection of millimeter and submillimeter waves

NASA Technical Reports Server (NTRS)

Richards, P. L.; Clarke, J.; Gildemeister, J. M.; Lanting, T.; Lee, A. T.

2001-01-01

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

Non-perturbative measurement of low-intensity charged particle beams

NASA Astrophysics Data System (ADS)

Fernandes, M.; Geithner, R.; Golm, J.; Neubert, R.; Schwickert, M.; Stöhlker, T.; Tan, J.; Welsch, C. P.

2017-01-01

Non-perturbative measurements of low-intensity charged particle beams are particularly challenging to beam diagnostics due to the low amplitude of the induced electromagnetic fields. In the low-energy antiproton decelerator (AD) and the future extra low energy antiproton rings at CERN, an absolute measurement of the beam intensity is essential to monitor the operation efficiency. Superconducting quantum interference device (SQUID) based cryogenic current comparators (CCC) have been used for measuring slow charged beams in the nA range, showing a very good current resolution. But these were unable to measure fast bunched beams, due to the slew-rate limitation of SQUID devices and presented a strong susceptibility to external perturbations. Here, we present a CCC system developed for the AD machine, which was optimised in terms of its current resolution, system stability, ability to cope with short bunched beams, and immunity to mechanical vibrations. This paper presents the monitor design and the first results from measurements with a low energy antiproton beam obtained in the AD in 2015. These are the first CCC beam current measurements ever performed in a synchrotron machine with both coasting and short bunched beams. It is shown that the system is able to stably measure the AD beam throughout the entire cycle, with a current resolution of 30 {nA}.

Open quantum systems, effective Hamiltonians, and device characterization

NASA Astrophysics Data System (ADS)

Duffus, S. N. A.; Dwyer, V. M.; Everitt, M. J.

2017-10-01

High fidelity models, which are able to both support accurate device characterization and correctly account for environmental effects, are crucial to the engineering of scalable quantum technologies. As it ensures positivity of the density matrix, one preferred model of open systems describes the dynamics with a master equation in Lindblad form. In practice, Linblad operators are rarely derived from first principles, and often a particular form of annihilator is assumed. This results in dynamical models that miss those additional terms which must generally be added for the master equation to assume the Lindblad form, together with the other concomitant terms that must be assimilated into an effective Hamiltonian to produce the correct free evolution. In first principles derivations, such additional terms are often canceled (or countered), frequently in a somewhat ad hoc manner, leading to a number of competing models. Whilst the implications of this paper are quite general, to illustrate the point we focus here on an example anharmonic system; specifically that of a superconducting quantum interference device (SQUID) coupled to an Ohmic bath. The resulting master equation implies that the environment has a significant impact on the system's energy; we discuss the prospect of keeping or canceling this impact and note that, for the SQUID, monitoring the magnetic susceptibility under control of the capacitive coupling strength and the externally applied flux results in experimentally measurable differences between a number of these models. In particular, one should be able to determine whether a squeezing term of the form X ̂P ̂+P ̂X ̂ should be present in the effective Hamiltonian or not. If model generation is not performed correctly, device characterization will be prone to systemic errors.

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

NASA Astrophysics Data System (ADS)

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

2013-10-01

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

Identifying Pelagic Habitat Hotspots of Neon Flying Squid in the Temperate Waters of the Central North Pacific

PubMed Central

Alabia, Irene D.; Saitoh, Sei-Ichi; Mugo, Robinson; Igarashi, Hiromichi; Ishikawa, Yoichi; Usui, Norihisa; Kamachi, Masafumi; Awaji, Toshiyuki; Seito, Masaki

2015-01-01

We identified the pelagic habitat hotspots of the neon flying squid (Ommastrephes bartramii) in the central North Pacific from May to July and characterized the spatial patterns of squid aggregations in relation to oceanographic features such as mesoscale oceanic eddies and the Transition Zone Chlorophyll-a Front (TZCF). The data used for the habitat model construction and analyses were squid fishery information, remotely-sensed and numerical model-derived environmental data from May to July 1999–2010. Squid habitat hotspots were deduced from the monthly Maximum Entropy (MaxEnt) models and were identified as regions of persistent high suitable habitat across the 12-year period. The distribution of predicted squid habitat hotspots in central North Pacific revealed interesting spatial and temporal patterns likely linked with the presence and dynamics of oceanographic features in squid’s putative foraging grounds from late spring to summer. From May to June, the inferred patches of squid habitat hotspots developed within the Kuroshio-Oyashio transition zone (KOTZ; 37–40°N) and further expanded north towards the subarctic frontal zone (SAFZ; 40–44°N) in July. The squid habitat hotspots within the KOTZ and areas west of the dateline (160°W-180°) were likely influenced and associated with the highly dynamic and transient oceanic eddies and could possibly account for lower squid suitable habitat persistence obtained from these regions. However, predicted squid habitat hotspots located in regions east of the dateline (180°-160°W) from June to July, showed predominantly higher squid habitat persistence presumably due to their proximity to the mean position of the seasonally-shifting TZCF and consequent utilization of the highly productive waters of the SAFZ. PMID:26571118

An efficient calibration method for SQUID measurement system using three orthogonal Helmholtz coils

NASA Astrophysics Data System (ADS)

Hua, Li; Shu-Lin, Zhang; Chao-Xiang, Zhang; Xiang-Yan, Kong; Xiao-Ming, Xie

2016-06-01

For a practical superconducting quantum interference device (SQUID) based measurement system, the Tesla/volt coefficient must be accurately calibrated. In this paper, we propose a highly efficient method of calibrating a SQUID magnetometer system using three orthogonal Helmholtz coils. The Tesla/volt coefficient is regarded as the magnitude of a vector pointing to the normal direction of the pickup coil. By applying magnetic fields through a three-dimensional Helmholtz coil, the Tesla/volt coefficient can be directly calculated from magnetometer responses to the three orthogonally applied magnetic fields. Calibration with alternating current (AC) field is normally used for better signal-to-noise ratio in noisy urban environments and the results are compared with the direct current (DC) calibration to avoid possible effects due to eddy current. In our experiment, a calibration relative error of about 6.89 × 10-4 is obtained, and the error is mainly caused by the non-orthogonality of three axes of the Helmholtz coils. The method does not need precise alignment of the magnetometer inside the Helmholtz coil. It can be used for the multichannel magnetometer system calibration effectively and accurately. Project supported by the “Strategic Priority Research Program (B)” of the Chinese Academy of Sciences (Grant No. XDB04020200) and the Shanghai Municipal Science and Technology Commission Project, China (Grant No. 15DZ1940902).

Ultra-high sensitivity moment magnetometry of geological samples using magnetic microscopy

NASA Astrophysics Data System (ADS)

Lima, Eduardo A.; Weiss, Benjamin P.

2016-09-01

Useful paleomagnetic information is expected to be recorded by samples with moments up to three orders of magnitude below the detection limit of standard superconducting rock magnetometers. Such samples are now detectable using recently developed magnetic microscopes, which map the magnetic fields above room-temperature samples with unprecedented spatial resolutions and field sensitivities. However, realizing this potential requires the development of techniques for retrieving sample moments from magnetic microscopy data. With this goal, we developed a technique for uniquely obtaining the net magnetic moment of geological samples from magnetic microscopy maps of unresolved or nearly unresolved magnetization. This technique is particularly powerful for analyzing small, weakly magnetized samples such as meteoritic chondrules and terrestrial silicate crystals like zircons. We validated this technique by applying it to field maps generated from synthetic sources and also to field maps measured using a superconducting quantum interference device (SQUID) microscope above geological samples with moments down to 10-15 Am2. For the most magnetic rock samples, the net moments estimated from the SQUID microscope data are within error of independent moment measurements acquired using lower sensitivity standard rock magnetometers. In addition to its superior moment sensitivity, SQUID microscope net moment magnetometry also enables the identification and isolation of magnetic contamination and background sources, which is critical for improving accuracy in paleomagnetic studies of weakly magnetic samples.

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

PubMed

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

2017-07-01

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

SQUID magnetometry from nanometer to centimeter length scales

NASA Astrophysics Data System (ADS)

Hatridge, Michael Jonathan

Information stored in magnetic fields plays an important role in everyday life. This information exists over a remarkably wide range of sizes, so that magnetometry at a variety of length scales can extract useful information. Examples at centimeter to millimeter length scales include measurement of spatial and temporal character of fields generated in the human brain and heart, and active manipulation of spins in the human body for non-invasive magnetic resonance imaging (MRI). At micron length scales, magnetometry can be used to measure magnetic objects such as flux qubits; at nanometer length scales it can be used to study individual magnetic domains, and even individual spins. The development of Superconducting QUantum Interference Device (SQUID) based magnetometer for two such applications, in vivo prepolarized, ultra-low field MRI of humans and dispersive readout of SQUIDs for micro- and nanoscale magnetometry, are the focus of this thesis. Conventional MRI has developed into a powerful clinical tool for imaging the human body. This technique is based on nuclear magnetic resonance of protons with the addition application of three-dimensional magnetic field gradients to encode spatial information. Most clinical MRI systems involve magnetic fields generated by superconducting magnets, and the current trend is to higher magnetic fields than the widely used 1.5-T systems. Nonetheless, there is ongoing interest in the development of less expensive imagers operating at lower fields. The prepolarized, SQUID detected ultra-low field MRI (ULF MRI) developed by the Clarke group allows imaging in very weak fields (typically 132 muT, corresponding to a resonant frequency of 5.6 kHz). At these low field strengths, there is enhanced contrast in the longitudinal relaxation time of various tissue types, enabling imaging of objects which are not visible to conventional MRI, for instance prostate cancer. We are currently investigating the contrast between normal and cancerous prostate tissue in ex vivo prostate specimens in collaboration with the UCSF Genitourinary Oncology/Prostate SPORE Tissue Core. In characterizing pairs of nominally normal and cancerous tissue, we measure a marked difference in the longitudinal relaxation times, with an average value of cancerous tissue 0.66 times shorter than normal prostate tissue. However, in vivo imaging is required to definitively demonstrate the feasibility of ULF MR imaging of prostate cancer. To that end, we have worked to improve the performance of the system to facilitate human imaging. This is accomplished by increasing the prepolarizing field amplitude, and minimizing magnetic noise in the SQUID detector. We have achieved polarizing fields as high as 150 mT and SQUID effective field noise below 1 fT Hz-1/2, enabling us to demonstrate proof-of-principle in vivo images of the human forearm with 2 x 2 x 10 mm3 resolution in 6 minutes. On a much smaller spatial scale, there is currently fundamental and technological interest in measuring and manipulating nanoscale magnets, particularly in the quantum coherent regime. The observation of the dynamics of such systems requires a magnetometer with not only exceptional sensitivity but also high gain, wide bandwidth and low backaction. We demonstrate a dispersive magnetometer consisting of a two-junction SQUID in parallel with an integrated, lumped-element capacitor. Input flux signals are encoded as a phase modulation of the microwave drive tone applied to the magnetometer, resulting in a single quadrature voltage signal. For strong drive power, the nonlinearity of the resonator results in quantum limited, phase sensitive parametric amplification of this signal. We have achieved a bandwidth of 20 MHz---approximately two orders of magnitude higher than dispersive devices of comparable sensitivity---with an effective flux noise of 0.29 muphi0 Hz-12 . This performance is in excellent agreement with our theoretical model.

Effect of Melanin Free Ink Extracted From Squid (Loligo sp.) on Proximate and Sensory Characteristics of Soft-Bone Milkfish (Chanos chanos) During Storage

NASA Astrophysics Data System (ADS)

Winarni Agustini, Tri; Hadiyanto; Wijayanti, Ima; Amalia, Ulfah; Benjakul, Soottawat

2018-02-01

Antioxidant could be extracted and isolated from squid inks. Squid ink in the form of melanin free ink (MFI) could be act as an electron donor which can stabilize free radicals in lipid oxidation. This study was carried out to assess the antioxidant activity of squid inks converted into MFI in different dilution and to optimize the extraction conditions for the application of MFI as an antioxidative agent on fish product. Three different types of MFI extracts i.e : pure squid ink, squid ink with 5 times dilution and squid ink with 10 times dilutions by using cooled ionized water (4°C). The ink was then centrifuged at 18.000 x g for 30 minutes at cooled centrifuge (4°C) followed by DPPH analysis. The results showed that the IC50 of MFI extracts were 2.84 ppm; 1.11 ppm and 0.34 ppm, respectively (p < 0.05). The results indicated that squid ink with 10 times dilution in extraction of MFI had the highest value in free radical inhibitory. Although the IC50 of three different dilutions are equally low, and are considered as very strong antioxidative agent, however, it showed that the MFI extracted from squid ink had the ability to prevent free radical

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.

Proposal for a transmon-based quantum router.

PubMed

Sala, Arnau; Blaauboer, M

2016-07-13

We propose an implementation of a quantum router for microwave photons in a superconducting qubit architecture consisting of a transmon qubit, SQUIDs and a nonlinear capacitor. We model and analyze the dynamics of operation of the quantum switch using quantum Langevin equations in a scattering approach and compute the photon reflection and transmission probabilities. For parameters corresponding to up-to-date experimental devices we predict successful operation of the router with probabilities above 94%.

Superconducting techniques for gravity survey and inertial navigation

NASA Technical Reports Server (NTRS)

Chan, H. A.; Moody, M. V.; Paik, H. J.; Parke, J. W.

1985-01-01

A three-axis gravity gradiometer is developed, in which the magnetic fields produced by persistent currents are modulated by motions of superconducting proof masses. The common-acceleration-induced errors are compensated for by a six-axis superconducting accelerometer with a single magnetically levitated proof mass, linear acceleration resolution of 4 x 10 to the -12th m/(s exp 2 Hz exp 1/2), and angular acceleration resolution of 3 x 10 to the -11th rad/(s exp 2 Hz exp 1/2). The testing of a prototype gradiometer revealed that the environment-induced noise limits the noise floor to 7 x 10 to the -10th/(s exp 2 Hz exp 1/2).

Initial Results from SQUID Sensor: Analysis and Modeling for the ELF/VLF Atmospheric Noise.

PubMed

Hao, Huan; Wang, Huali; Chen, Liang; Wu, Jun; Qiu, Longqing; Rong, Liangliang

2017-02-14

In this paper, the amplitude probability density (APD) of the wideband extremely low frequency (ELF) and very low frequency (VLF) atmospheric noise is studied. The electromagnetic signals from the atmosphere, referred to herein as atmospheric noise, was recorded by a mobile low-temperature superconducting quantum interference device (SQUID) receiver under magnetically unshielded conditions. In order to eliminate the adverse effect brought by the geomagnetic activities and powerline, the measured field data was preprocessed to suppress the baseline wandering and harmonics by symmetric wavelet transform and least square methods firstly. Then statistical analysis was performed for the atmospheric noise on different time and frequency scales. Finally, the wideband ELF/VLF atmospheric noise was analyzed and modeled separately. Experimental results show that, Gaussian model is appropriate to depict preprocessed ELF atmospheric noise by a hole puncher operator. While for VLF atmospheric noise, symmetric α -stable (S α S) distribution is more accurate to fit the heavy-tail of the envelope probability density function (pdf).

High electrochemical capacitor performance of oxygen and nitrogen enriched activated carbon derived from the pyrolysis and activation of squid gladius chitin

NASA Astrophysics Data System (ADS)

Raj, C. Justin; Rajesh, Murugesan; Manikandan, Ramu; Yu, Kook Hyun; Anusha, J. R.; Ahn, Jun Hwan; Kim, Dong-Won; Park, Sang Yeup; Kim, Byung Chul

2018-05-01

Activated carbon containing nitrogen functionalities exhibits excellent electrochemical property which is more interesting for several renewable energy storage and catalytic applications. Here, we report the synthesis of microporous oxygen and nitrogen doped activated carbon utilizing chitin from the gladius of squid fish. The activated carbon has large surface area of 1129 m2 g-1 with microporous network and possess ∼4.04% of nitrogen content in the form of pyridinic/pyrrolic-N, graphitic-N and N-oxide groups along with oxygen and carbon species. The microporous oxygen/nitrogen doped activated carbon is utilize for the fabrication of aqueous and flexible supercapacitor electrodes, which presents excellent electrochemical performance with maximum specific capacitance of 204 Fg-1 in 1 M H2SO4 electrolyte and 197 Fg-1 as a flexible supercapacitor. Moreover, the device displays 100% of specific capacitance retention after 25,000 subsequent charge/discharge cycles in 1 M H2SO4 electrolyte.

Linear arrangements of nano-scale ferromagnetic particles spontaneously formed in a copper-base Cu-Ni-Co alloy

NASA Astrophysics Data System (ADS)

Sakakura, Hibiki; Kim, Jun-Seop; Takeda, Mahoto

2018-03-01

We have investigated the influence of magnetic interactions on the microstructural evolution of nano-scale granular precipitates formed spontaneously in an annealed Cu-20at%Ni-5at%Co alloy and the associated changes of magnetic properties. The techniques used included transmission electron microscopy, superconducting quantum interference device (SQUID) magnetometry, magneto-thermogravimetry (MTG), and first-principles calculations based on the method of Koster-Korringa-Rostker with the coherent potential approximation. Our work has revealed that the nano-scale spherical and cubic precipitates which formed on annealing at 873 K and 973 K comprise mainly cobalt and nickel with a small amount of copper, and are arranged in the 〈1 0 0〉 direction of the copper matrix. The SQUID and MTG measurements suggest that magnetic properties such as coercivity and Curie temperature are closely correlated with the microstructure. The combination of results suggests that magnetic interactions between precipitates during annealing can explain consistently the observed precipitation phenomena.

Initial Results from SQUID Sensor: Analysis and Modeling for the ELF/VLF Atmospheric Noise

PubMed Central

Hao, Huan; Wang, Huali; Chen, Liang; Wu, Jun; Qiu, Longqing; Rong, Liangliang

2017-01-01

In this paper, the amplitude probability density (APD) of the wideband extremely low frequency (ELF) and very low frequency (VLF) atmospheric noise is studied. The electromagnetic signals from the atmosphere, referred to herein as atmospheric noise, was recorded by a mobile low-temperature superconducting quantum interference device (SQUID) receiver under magnetically unshielded conditions. In order to eliminate the adverse effect brought by the geomagnetic activities and powerline, the measured field data was preprocessed to suppress the baseline wandering and harmonics by symmetric wavelet transform and least square methods firstly. Then statistical analysis was performed for the atmospheric noise on different time and frequency scales. Finally, the wideband ELF/VLF atmospheric noise was analyzed and modeled separately. Experimental results show that, Gaussian model is appropriate to depict preprocessed ELF atmospheric noise by a hole puncher operator. While for VLF atmospheric noise, symmetric α-stable (SαS) distribution is more accurate to fit the heavy-tail of the envelope probability density function (pdf). PMID:28216590

Analytical balance-based Faraday magnetometer

NASA Astrophysics Data System (ADS)

Riminucci, Alberto; Uhlarz, Marc; De Santis, Roberto; Herrmannsdörfer, Thomas

2017-03-01

We introduce a Faraday magnetometer based on an analytical balance in which we were able to apply magnetic fields up to 0.14 T. We calibrated it with a 1 mm Ni sphere previously characterized in a superconducting quantum interference device (SQUID) magnetometer. The proposed magnetometer reached a theoretical sensitivity of 3 × 10-8 A m2. We demonstrated its operation on magnetic composite scaffolds made of poly(ɛ-caprolactone)/iron-doped hydroxyapatite. To confirm the validity of the method, we measured the same scaffold properties in a SQUID magnetometer. The agreement between the two measurements was within 5% at 0.127 T and 12% at 24 mT. With the addition, for a small cost, of a permanent magnet and computer controlled linear translators, we were thus able to assemble a Faraday magnetometer based on an analytical balance, which is a virtually ubiquitous instrument. This will make simple but effective magnetometry easily accessible to most laboratories, in particular, to life sciences ones, which are increasingly interested in magnetic materials.

Nondegenerate parametric oscillations in a tunable superconducting resonator

NASA Astrophysics Data System (ADS)

Bengtsson, Andreas; Krantz, Philip; Simoen, Michaël; Svensson, Ida-Maria; Schneider, Ben; Shumeiko, Vitaly; Delsing, Per; Bylander, Jonas

2018-04-01

We investigate nondegenerate parametric oscillations in a superconducting microwave multimode resonator that is terminated by a superconducting quantum interference device (SQUID). The parametric effect is achieved by modulating magnetic flux through the SQUID at a frequency close to the sum of two resonator-mode frequencies. For modulation amplitudes exceeding an instability threshold, self-sustained oscillations are observed in both modes. The amplitudes of these oscillations show good quantitative agreement with a theoretical model. The oscillation phases are found to be correlated and exhibit strong fluctuations which broaden the oscillation spectral linewidths. These linewidths are significantly reduced by applying a weak on-resonant tone, which also suppresses the phase fluctuations. When the weak tone is detuned, we observe synchronization of the oscillation frequency with the frequency of the input. For the detuned input, we also observe an emergence of three idlers in the output. This observation is in agreement with theory indicating four-mode amplification and squeezing of a coherent input.

Atomic magnetometer for human magnetoencephalograpy.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schwindt, Peter; Johnson, Cort N.

2010-12-01

We have developed a high sensitivity (<5 fTesla/{radical}Hz), fiber-optically coupled magnetometer to detect magnetic fields produced by the human brain. This is the first demonstration of a noncryogenic sensor that could replace cryogenic superconducting quantum interference device (SQUID) magnetometers in magnetoencephalography (MEG) and is an important advance in realizing cost-effective MEG. Within the sensor, a rubidium vapor is optically pumped with 795 laser light while field-induced optical rotations are measured with 780 nm laser light. Both beams share a single optical axis to maximize simplicity and compactness. In collaboration with neuroscientists at The Mind Research Network in Albuquerque, NM, themore » evoked responses resulting from median nerve and auditory stimulation were recorded with the atomic magnetometer and a commercial SQUID-based MEG system with signals comparing favorably. Multi-sensor operation has been demonstrated with two AMs placed on opposite sides of the head. Straightforward miniaturization would enable high-density sensor arrays for whole-head magnetoencephalography.« less

Design and optimisation of low heat load liquid helium cryostat to house cryogenic current comparator in antiproton decelerator at CERN

NASA Astrophysics Data System (ADS)

Lees, A.; Koettig, T.; Fernandes, M.; Tan, J.

2017-02-01

The Cryogenic Current Comparator (CCC) is installed in the low-energy Antiproton Decelerator (AD) at CERN to make an absolute measurement of the beam intensity. Operating below 4.2 K, it is based on a superconducting quantum interference device (SQUID) and employs a superconducting niobium shield to supress magnetic field components not linked to the beam current. The AD contains no permanent cryogenic infrastructure so the local continuous liquefaction of helium using a pulse-tube is required; limiting the available cooling power to 0.69 W at 4.2K. Due to the sensitivity of the SQUID to variations in magnetic fields, the CCC is highly sensitive to mechanical vibration which is limited to a minimum by the support systems of the cryostat. This article presents the cooling system of the cryostat and discusses the design challenges overcome to minimise the transmission of vibration to the CCC while operating within the cryogenic limits imposed by the cooling system.

Chip-Scale Atomic Magnetometers

NASA Astrophysics Data System (ADS)

Knappe, Svenja

2010-03-01

Atomic magnetometers have reached sensitivities rivaling those of superconducting quantum interference devices (SQUIDs) in some frequency ranges [1]. A major advancement in atomic magnetometry was made possible by implementing interrogation schemes that suppress spin-exchange collisions between the alkali atoms [2]. Good signal-to-noise can be achieved by operation at very high alkali densities. At the same time, it introduces the challenge to create uniform spin-polarization and monitor the atomic precession about the magnetic field in atomic vapors with large optical densities. Off-resonant detection of the polarization rotation rather than the absorption is essential to operate in this regime. By use of microfabrication methods, we are miniaturizing such atomic magnetometers. They consist of miniature vapor cells with volumes of a few cubic millimeters integrated with micro-optical components. We present the advancement in sensitivities of such devices over nearly four orders of magnitude [3]. This allows for small low-power room-temperature devices with sensitivities that get close to those of SQUIDs in the frequency range around 100 Hz. We outline the current performance of chip-scale atomic magnetometers and the major challenges. Apart from efficient pumping and probing at high optical densities, these include magnetic noise caused by several sensor components and environmental factors, noise on the light fields, as well as magnetic fields from current-carrying parts, such as heaters, lasers, and photodetectors.[4pt] [1] Allred et al., Phys. Rev. Lett. 89, 130801 (2002) [0pt] [2] Happer and Tam, Phys. Rev. A 16, 1877 (1977) [0pt] [3] Griffith et al., Appl. Phys. Lett 94, 023502 (2009)

The mechanics of locomotion in the squid Loligo pealei: locomotory function and unsteady hydrodynamics of the jet and intramantle pressure.

PubMed

Anderson, E J; DeMont, M E

2000-09-01

High-speed, high-resolution digital video recordings of swimming squid (Loligo pealei) were acquired. These recordings were used to determine very accurate swimming kinematics, body deformations and mantle cavity volume. The time-varying squid profile was digitized automatically from the acquired swimming sequences. Mantle cavity volume flow rates were determined under the assumption of axisymmetry and the condition of incompressibility. The data were then used to calculate jet velocity, jet thrust and intramantle pressure, including unsteady effects. Because of the accurate measurements of volume flow rate, the standard use of estimated discharge coefficients was avoided. Equations for jet and whole-cycle propulsive efficiency were developed, including a general equation incorporating unsteady effects. Squid were observed to eject up to 94 % of their intramantle working fluid at relatively high swimming speeds. As a result, the standard use of the so-called large-reservoir approximation in the determination of intramantle pressure by the Bernoulli equation leads to significant errors in calculating intramantle pressure from jet velocity and vice versa. The failure of this approximation in squid locomotion also implies that pressure variation throughout the mantle cannot be ignored. In addition, the unsteady terms of the Bernoulli equation and the momentum equation proved to be significant to the determination of intramantle pressure and jet thrust. Equations of propulsive efficiency derived for squid did not resemble Froude efficiency. Instead, they resembled the equation of rocket motor propulsive efficiency. The Froude equation was found to underestimate the propulsive efficiency of the jet period of the squid locomotory cycle and to overestimate whole-cycle propulsive efficiency when compared with efficiencies calculated from equations derived with the squid locomotory apparatus in mind. The equations for squid propulsive efficiency reveal that the refill period of squid plays a greater role, and the jet period a lesser role, in the low whole-cycle efficiencies predicted in squid and similar jet-propelled organisms. These findings offer new perspectives on locomotory hydrodynamics, intramantle pressure measurements and functional morphology with regard to squid and other jet-propelled organisms.

Prolonged Decline of Jumbo Squid (Dosidicus gigas) Landings in the Gulf of California is Associated with Chronically low wind Stress and Decreased Chlorophyll a after El Niño 2009-2010

NASA Astrophysics Data System (ADS)

Robinson, C. J.; Gomez-Gutierrez, J.

2016-02-01

Dosidicus gigas (jumbo squid) is an ecologically relevant predator in the Gulf of California, Mexico, where it supports an economically valuable fishery. The commercial jumbo squid fishery in the Gulf declined steeply after an El Niño event in 2009-2010, and subsequent landings have remained at historically low levels in the relevant squid fishing centers (Guaymas, Sonora, and Santa Rosalia, Baja California Sur). In this paper, we examined wind speed and satellite chlorophyll a concentrations on the jumbo squid fishing grounds as factors that would be expected to be relevant to this prolonged period of low landings. Analysis from local weather stations, remote sensing and fishery data showed that low jumbo squid landings from 2010 to 2015 occurred during a period abnormally weak winter/spring winds and extremely low chlorophyll a concentrations off the East Guaymas Basin. Results indicate that the squid fishing area in the Guaymas region has been chronically impoverished during this period, and that this area may no longer be a productive habitat for jumbo squid. In response to this decreased productivity, size-at-maturity of jumbo squid showed a drastic decrease over the same period. Results are compared with the effect of El Niño 1997-1998 on the jumbo squid fishery and size-at-maturity of this species in the Gulf of California. The key difference between the recovery phases for El Niño 1997-1998 versus El Niño2009-2010 was the wind intensity as measured in the Guaymas fishing area.

Calibrating a tensor magnetic gradiometer using spin data

USGS Publications Warehouse

Bracken, Robert E.; Smith, David V.; Brown, Philip J.

2005-01-01

Scalar magnetic data are often acquired to discern characteristics of geologic source materials and buried objects. It is evident that a great deal can be done with scalar data, but there are significant advantages to direct measurement of the magnetic gradient tensor in applications with nearby sources, such as unexploded ordnance (UXO). To explore these advantages, we adapted a prototype tensor magnetic gradiometer system (TMGS) and successfully implemented a data-reduction procedure. One of several critical reduction issues is the precise determination of a large group of calibration coefficients for the sensors and sensor array. To resolve these coefficients, we devised a spin calibration method, after similar methods of calibrating space-based magnetometers (Snare, 2001). The spin calibration procedure consists of three parts: (1) collecting data by slowly revolving the sensor array in the Earth?s magnetic field, (2) deriving a comprehensive set of coefficients from the spin data, and (3) applying the coefficients to the survey data. To show that the TMGS functions as a tensor gradiometer, we conducted an experimental survey that verified that the reduction procedure was effective (Bracken and Brown, in press). Therefore, because it was an integral part of the reduction, it can be concluded that the spin calibration was correctly formulated with acceptably small errors.

Cadmium content in fresh and canned squid (Loligo opalescens) from the Pacific coastal waters of California (USA).

PubMed

Galitsopoulou, A; Georgantelis, D; Kontominas, M G

2009-01-01

Cadmium (Cd) levels were determined in 70 samples of mantle tissue and 70 whole individual squid (Loligo opalescens; commercially known as California squid). Samples were collected from the coastal zones of California (USA) during the period 2007/2008. To further investigate consumer exposure to processed fishery products, cadmium concentration was also determined in 200 canned samples of squid. Cd concentrations in raw mantle were low, between 0.01 and 0.29 mg kg(-1) and below the tolerance limit of current regulations (1 mg kg(-1)). Respective concentrations in whole individuals were significantly higher, ranging from 0.51 to 1.18 mg kg(-1), attributed to the presence of the visceral portion in whole squid samples. Cd concentrations varied in relation to age and sex of squid, indicating that several physiological factors may influence accumulation. Furthermore, canning of squid substantially enhanced Cd levels. Cd concentration ranged 0.17-0.67 mg kg(-1) in canned mantle tissue and 0.86-2.07 mg kg(-1) in canned whole squid samples, due to both concentration after canning and movement of the metal between different tissues. Several biological compounds, including metallothioneins, nucleic acids and enzymes, may affect Cd concentrations in commercial fishery products.

A Transportable Gravity Gradiometer Based on Atom Interferometry

NASA Technical Reports Server (NTRS)

Yu, Nan; Thompson, Robert J.; Kellogg, James R.; Aveline, David C.; Maleki, Lute; Kohel, James M.

2010-01-01

A transportable atom interferometer-based gravity gradiometer has been developed at JPL to carry out measurements of Earth's gravity field at ever finer spatial resolutions, and to facilitate high-resolution monitoring of temporal variations in the gravity field from ground- and flight-based platforms. Existing satellite-based gravity missions such as CHAMP and GRACE measure the gravity field via precise monitoring of the motion of the satellites; i.e. the satellites themselves function as test masses. JPL's quantum gravity gradiometer employs a quantum phase measurement technique, similar to that employed in atomic clocks, made possible by recent advances in laser cooling and manipulation of atoms. This measurement technique is based on atomwave interferometry, and individual laser-cooled atoms are used as drag-free test masses. The quantum gravity gradiometer employs two identical atom interferometers as precision accelerometers to measure the difference in gravitational acceleration between two points (Figure 1). By using the same lasers for the manipulation of atoms in both interferometers, the accelerometers have a common reference frame and non-inertial accelerations are effectively rejected as common mode noise in the differential measurement of the gravity gradient. As a result, the dual atom interferometer-based gravity gradiometer allows gravity measurements on a moving platform, while achieving the same long-term stability of the best atomic clocks. In the laboratory-based prototype (Figure 2), the cesium atoms used in each atom interferometer are initially collected and cooled in two separate magneto-optic traps (MOTs). Each MOT, consisting of three orthogonal pairs of counter-propagating laser beams centered on a quadrupole magnetic field, collects up to 10(exp 9) atoms. These atoms are then launched vertically as in an atom fountain by switching off the magnetic field and introducing a slight frequency shift between pairs of lasers to create a moving rest frame for the trapped atoms. While still in this moving-frame molasses, the laser frequencies are further detuned from the atomic resonance (while maintaining this relative frequency shift) to cool the atom cloud's temperature to 2 K or below, corresponding to an rms velocity of less than 2 cm/s. After launch, the cold atoms undergo further state and velocity selection to prepare for atom interferometry. The atom interferometers are then realized using laser-induced stimulated Raman transitions to perform the necessary manipulations of each atom, and the resulting interferometer phase is measured using laser-induced fluorescence for state-normalized detection. More than 20 laser beams with independent controls of frequency, phase, and intensity are required for this measurement sequence. This instrument can facilitate the study of Earth's gravitational field from surface and air vehicles, as well as from space by allowing gravity mapping from a low-cost, single spacecraft mission. In addition, the operation of atom interferometer-based instruments in space offers greater sensitivity than is possible in terrestrial instruments due to the much longer interrogation times available in the microgravity environment. A space-based quantum gravity gradiometer has the potential to achieve sensitivities similar to the GRACE mission at long spatial wavelengths, and will also have resolution similar to GOCE for measurement at shorter length scales.

Self powered sensing by combining novel sensor architectures with energy harvesting

NASA Astrophysics Data System (ADS)

Bedekar, Vishwas Narayan

The sensing techniques investigated in this thesis utilize piezoelectric materials, piezoresistive materials, and magnetoelectric composites. Prior studies on structural health monitoring have demonstrated the use and promise of piezoelectric sensors. In this research, impedance spectroscopy based sensing technique was investigated with respect to two parameters (i) effect of the piezoelectric vibration mode on damage index metric, and (ii) selection of frequency band through manipulation of the electrode size and shape. These results were then used to determine sensor geometry and dimensions for detecting surface defects, fatigue and corrosion. Based upon these results, power requirement for structural health monitoring sensors was determined. Next, piezoelectric materials were coupled with magnetostrictive material for novel magnetic field gradient sensing. The ceramic -- ceramic (CC) gradiometer resembles in functionality a magnetoelectric transformer. It measures the magnetic field gradient and sensitivity with respect to a reference value. The CC gradiometer designed in this study was based upon the magnetoelectric (ME) composites and utilizes the ring-dot piezoelectric transformer structure working near resonance as the basis. This study investigated the gradiometer design and characterized the performance of gradiometer based upon Terfenol--D -- PZT composites. Based upon these results, next a metal -- ceramic gradiometer consisting of PZT and nickel was designed and characterized. In this thesis, two different designs of gradiometer with nickel and PZT laminate composites were fabricated. Nickel was chosen over other materials considering its co-firing ability with PZT. It can give a better control over dimensional parameters of the gradiometer sample and further size reduction is possible with tape casting technique. Detailed theoretical analysis was conducted in order to understand the experimental results. In order to significantly reduce the power consumption of health monitoring and magnetic field sensors, bottom -- up design of structural health monitoring and magnetic field sensors was investigated. A MWCNT/SiCN nanotube template was developed that exhibits piezoresistive effect. Next, a novel nanotube morphology "nanoNecklace" was synthesized that consists of BaTiO 3 (BTO) nanoparticles decorated along the surface of SiCN. Monolayer coating of SiCN on MWCNT serves two purposes: (i) modifies the surface wetting characteristics, and (ii) enhances the piezoresistive effect. Investigation of the mechanisms that provide periodic arrangement of BTO on nanotube surface was conducted using HRTEM and contact angle measurements. Next, we tried to modify the surface wetting characteristics of MWCNTs in order to get a full coating of BTO nanoparticles. The SiCN/MWCNT approach was further extended to fabricate magnetoelectric nanowire based sensors designs. In this approach a SiCN-NT template was coated with BTO and CoFe2O4 (CFO) nanoparticles. Microstructural studies indicated the presence of piezoelectric (BTO) as well as magnetic (CFO) material on the nanotube surface. In order to power the sensors from mechanical vibrations, we investigated two different techniques, (i) piezoelectric and (ii) inductive. An analytical model for energy harvesting from bimorph transducer was developed which was confirmed by experimental measurements. The results show that power density of bimorph transducer can be enhanced by increasing the magnitude of product (d.g), where d is the piezoelectric strain constant and g is the piezoelectric voltage constant. Under inductive energy harvesting, we designed and fabricated a small scale harvester that was integrated inside a pen commonly carried by humans to harvest vibration energy. Inductive energy harvesting was selected in order to achieve high power at lower frequencies. The prototype cylindrical harvester was found to generate 3mW at 5 Hz and 1mW at 3.5 Hz operating under displacement amplitude of 16mm (corresponding to an acceleration of approximately 1.14 grms at 5Hz and 0.56 grms at 3.5 Hz, respectively). (Abstract shortened by UMI.)

SETA Support for the DARPA Microelectronics Technology Insertion Program of the Microelectronics Technology Office

DTIC Science & Technology

1992-08-17

Conclusions. Key personnel planned and administered the 193-nm lithography SBIR workshop on May 7, 1992 as well as planned the GaAs Insertion...converters can use Josephson junctions (JJ) to improve performance. Superconductive quantum interference devices (SQUIDs), such as JJs, are used to form...forward control of a lithography stepper. Mark Conner at Booz-Allen has copies of the charts. You should take a few minutes to review them. I asked Costos

Detection of bacteria in suspension using a superconducting Quantum interference device

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grossman, H.L.; Myers, W.R.; Vreeland, V.J.

2003-06-09

We demonstrate a technique for detecting magnetically-labeled Listeria monocytogenes and for measuring the binding rate between antibody-linked magnetic particles and bacteria. This assay, which is both sensitive and straightforward to perform, can quantify specific bacteria in a sample without the need to immobilize the bacteria or wash away unbound magnetic particles. In the measurement, we add 50 nm diameter superparamagnetic particles, coated with antibodies, to a liquid sample containing L. monocytogenes. We apply a pulsed magnetic field to align the magnetic dipole moments and use a high transition temperature Superconducting Quantum Interference Device (SQUID), an extremely sensitive detector of magneticmore » flux, to measure the magnetic relaxation signal when the field is turned off. Unbound particles randomize direction by Brownian rotation too quickly to be detected. In contrast, particles bound to L. monocytogenes are effectively immobilized and relax in about 1 s by rotation of the internal dipole moment. This Neel relaxation process is detected by the SQUID. The measurements indicate a detection limit of (5.6 {+-} 1.1) x 10{sup 6} L. monocytogenes for a 20 {micro}L sample volume. If the sample volume were reduced to 1 nL, we estimate that the detection limit could be improved to 230 {+-} 40 L. monocytogenes cells. Time-resolved measurements yield the binding rate between the particles and bacteria.« less

Biosensing utilizing magnetic markers and superconducting quantum interference devices

NASA Astrophysics Data System (ADS)

Enpuku, Keiji; Tsujita, Yuya; Nakamura, Kota; Sasayama, Teruyoshi; Yoshida, Takashi

2017-05-01

Magnetic biosensing techniques that are based on the use of bio-functionalized magnetic nanoparticles (magnetic markers) and superconducting quantum interference devices (SQUIDs) are expected to have various advantages when compared with conventional biosensing methods. In this paper, we review the recent progress made in magnetic biosensing techniques. First, we describe the most important parameters of magnetic markers that are intended for use in biosensing, i.e., the magnetic signal and the relaxation time that are determined by the Brownian and/or Néel relaxation mechanisms. We note that these parameters are significantly dependent on the marker size, and as a result, commercial markers exhibit a wide variety of values for these key parameters. Next, we describe three measurement methods that have been developed based on the magnetic properties of these markers, i.e., AC susceptibility, relaxation and remanence-based measurement methods. The weak (picotesla-range) signals emitted by the markers can be measured precisely with a SQUID system using these methods. Finally, we give examples of biosensing for in vitro and in vivo medical diagnosis applications. For in vitro diagnosis, high-sensitivity detection of various biological targets has been demonstrated without use of any washing process to separate the bound and free markers. For in vivo applications, detection of the quantities and the three-dimensional positions of the markers that have been injected into the test subject are demonstrated. These results confirm the effectiveness of magnetic biosensing techniques.

Multilayer MgB{sub 2} superconducting quantum interference filter magnetometers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Galan, Elias; Melbourne, Thomas; Davidson, Bruce A.

2016-04-25

We report two types of all-MgB{sub 2} superconductive quantum interference filter (SQIF) magnetometers that can measure absolute magnetic fields with high sensitivity. In one configuration, the SQIFs were made of 20 multilayer nonplanar all-MgB{sub 2} superconducting quantum interference devices (SQUIDs) connected in parallel with loop areas ranging in size from 0.4 to 3.6 μm{sup 2}. These devices are sensitive to magnetic fields parallel to the substrate and show a single antipeak from 3 to 16 K with a maximum transfer function of ∼16 V/T at 3 K and a field noise of ∼110 pT/Hz{sup 1/2} above 100 Hz at 10 K. In a second configuration, themore » SQIFs were made with 16 planar SQUIDs connected in parallel with loop areas ranging in size from 4 μm{sup 2} to 25 μm{sup 2} and are sensitive to the magnetic fields perpendicular to the substrate. The planar SQIF shows a single antipeak from 10 to 22 K with a maximum transfer function of 7800 V/T at 10 K and a field noise of ∼70 pT/Hz{sup 1/2} above 100 Hz at 20 K.« less

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

A tunable microstrip SQUID amplifier for the Axion Dark Matter eXperiment (ADMX)

NASA Astrophysics Data System (ADS)

O'Kelley, Sean; Hansen, Jorn; Weingarten, Elan; Mueck, Michael; Hilton, Gene; Clarke, John

2014-03-01

We describe a microstrip SQUID (Superconducting QUantum Interference Device) amplifier (MSA) used as the photon detector in the Axion Dark Matter eXperiment (ADMX). Cooled to 100 mK or lower, an optimized MSA approaches the quantum limit of detection. The axion dark matter is detected via Primakoff conversion to a microwave photon in a high-Q (~ 105) tunable microwave cavity, currently cooled to about 1.6 K, in the presence of a 7-tesla magnetic field. The MSA consists of a square loop of thin Nb film, incorporating two Josephson tunnel junctions with resistive shunts to prevent hysteresis in the current-voltage characteristic. The microstrip is a square Nb coil deposited over an intervening insulating layer. Since the photon frequency is determined by the unknown axion mass, the cavity and amplifier must be tunable over a broad frequency range. Tunability is achieved by terminating the microstrip with a GaAs varactor diode with a voltage-controlled capacitance that enables us to vary the resonance from nearly 1/2 to 1/4 of a wavelength. With the SQUID current-biased in the voltage state, we demonstrate a gain of typically 20 dB over nearly one octave, 415 MHz to 800 MHz. Supported by DOE Grants DE-FG02-97ER41029, DE-FG02-96ER40956, DE-AC52-07NA27344, DE-AC03-76SF00098, NSF grants PHY-1067242 and PHY-1306729, and the Livermore LDRD program.

Impact of SQUIDs on functional imaging in neuroscience

NASA Astrophysics Data System (ADS)

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

2014-04-01

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

Whole-head SQUID system in a superconducting magnetic shield.

PubMed

Ohta, H; Matsui, T; Uchikawa, Y

2004-11-30

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.

Potential use of stable isotope and fatty acid analyses for traceability of geographic origins of jumbo squid (Dosidicus gigas).

PubMed

Gong, Yi; Li, Yunkai; Chen, Xinjun; Chen, Ling

2018-04-15

Squid is an important seafood resource for Asian and European countries. With the continuous development of processed squid products, an effective traceability system has become increasingly prominent. Here, we attempt to trace the fishery products of the main target species, jumbo squid (Dosidicus gigas), by using biochemical tracers. Carbon and nitrogen isotope ratios (δ 13 C and δ 15 N values) and fatty acid profiles were identified in squid from three harvest locations in the eastern Pacific Ocean by isotope ratio mass spectrometry and gas chromatography/mass spectrometry, respectively. Comparative analysis was used to evaluate the geographic variations in tracers and to identify the suitable discriminatory variables among origins. Significant spatial variations were found in isotopic values and fatty acid profiles in squid muscle tissues, possibly because of different food availability and/or oceanographic conditions that each group experiences at a given location. The stepwise discriminant analysis indicated that δ 15 N, C16:1n7, C17:1n7, C18:2n6, C20:1 and C20:4n6 were effective variables at differentiating origin. Combined use of stable isotope ratios and fatty acid analyses could trace geographic origins of jumbo squid. This study provides an alternative approach for improving authenticity evaluation of commercial squid products. Copyright © 2018 John Wiley & Sons, Ltd.

Timing of squid migration reflects North Atlantic climate variability.

PubMed

Sims, D W; Genner, M J; Southward, A J; Hawkins, S J

2001-12-22

The environmental and biotic conditions affecting fisheries for cephalopods are only partially understood. A problem central to this is how climate change may influence population movements by altering the availability of thermal resources. In this study we investigate the links between climate and sea-temperature changes and squid arrival time off southwestern England over a 20-year period. We show that veined squid (Loligo forbesi) migrate eastward in the English Channel earlier when water in the preceding months is warmer, and that higher temperatures and early arrival correspond with warm (positive) phases of the North Atlantic oscillation (NAO). The timing of squid peak abundance advanced by 120-150 days in the warmest years ('early' years) compared with the coldest ('late' years). Furthermore, sea-bottom temperature was closely linked to the extent of squid movement. Temperature increases over the five months prior to and during the month of peak squid abundance did not differ between early and late years, indicating squid responded to temperature changes independently of time of year. We conclude that the temporal variation in peak abundance of squid seen off Plymouth represents temperature-dependent movement, which is in turn mediated by climatic changes associated with the NAO. Such climate-mediated movement may be a widespread characteristic of cephalopod populations worldwide, and may have implications for future fisheries management because global warming may alter both the timing and location of peak population abundance.

Therapeutic Significance of Loligo vulgaris (Lamarck, 1798) ink Extract: A Biomedical Approach.

PubMed

Nadarajah, Sri Kumaran; Vijayaraj, Radha; Mani, Jayaprakashvel

2017-12-01

The squid ink extract is well known for its biomedical properties. In this study, squid Loligo vulgaris was collected from Tuticorin costal water, Bay of Bengal, India. Proximate composition of the crude squid ink was studied and found to have protein as the major component over lipid and carbohydrates. Further, bioactive fractions of squid ink were extracted with ethanol, and therapeutic applications such as hemolytic, antioxidant, antimicrobial, and in vitro anti-inflammatory properties were analyzed using standard methods. In hemolytic assay, the squid ink extract exhibited a maximum hemolytic activity of 128 hemolytic unit against tested erythrocytes. In DPPH assay, the ethanolic extract of squid ink has exhibited an antioxidant activity of 83.5%. The squid ink was found to be potent antibacterial agent against the pathogens tested. 200 μL of L. vulgaris ink extract showed remarkable antibacterial activity as zone of inhibition against Escherichia coli (28 mm), Klebsiella pneumoniae (22 mm), Pseudomonas aeruginosa (21 mm), and Staphylococcus aureus (24 mm). The 68.9% inhibition of protein denaturation by the squid ink extract indicated that it has very good in vitro anti-inflammatory properties. The Fourier transform infrared spectroscopy analysis of the ethanolic extracts of the squid ink indicated the presence of functional groups such as 1° and 2° amines, amides, alkynes (terminal), alkenes, aldehydes, nitriles, alkanes, aliphatic amines, carboxylic acids, and alkyl halides, which complements the biochemical background of therapeutic applications. Hence, results of this study concluded that the ethanolic extract of L. vulgaris has many therapeutic applications such as antimicrobial, antioxidant, and anti-inflammatory activities. Squid ink is very high in a number of important nutrients. It's particularly high in antioxidants for instance, which as well all know help to protect the cells and the heart against damage from free radicals. In the present study, the squid ink have antioxidant, anti-inflammatory and cytotoxic properties and can be considered as promising the developing the drugs. Abbreviations Used: DPPH: 2,2-diphenyl-1-picrylhydrazyl, FTIR: Fourier-transform infrared spectroscopy, BSA: Bovine Serum Albumin.

Therapeutic Significance of Loligo vulgaris (Lamarck, 1798) ink Extract: A Biomedical Approach

PubMed Central

Nadarajah, Sri Kumaran; Vijayaraj, Radha; Mani, Jayaprakashvel

2017-01-01

Background: The squid ink extract is well known for its biomedical properties. Objective: In this study, squid Loligo vulgaris was collected from Tuticorin costal water, Bay of Bengal, India. Materials and Methods: Proximate composition of the crude squid ink was studied and found to have protein as the major component over lipid and carbohydrates. Further, bioactive fractions of squid ink were extracted with ethanol, and therapeutic applications such as hemolytic, antioxidant, antimicrobial, and in vitro anti-inflammatory properties were analyzed using standard methods. Results: In hemolytic assay, the squid ink extract exhibited a maximum hemolytic activity of 128 hemolytic unit against tested erythrocytes. In DPPH assay, the ethanolic extract of squid ink has exhibited an antioxidant activity of 83.5%. The squid ink was found to be potent antibacterial agent against the pathogens tested. 200 μL of L. vulgaris ink extract showed remarkable antibacterial activity as zone of inhibition against Escherichia coli (28 mm), Klebsiella pneumoniae (22 mm), Pseudomonas aeruginosa (21 mm), and Staphylococcus aureus (24 mm). The 68.9% inhibition of protein denaturation by the squid ink extract indicated that it has very good in vitro anti-inflammatory properties. The Fourier transform infrared spectroscopy analysis of the ethanolic extracts of the squid ink indicated the presence of functional groups such as 1° and 2° amines, amides, alkynes (terminal), alkenes, aldehydes, nitriles, alkanes, aliphatic amines, carboxylic acids, and alkyl halides, which complements the biochemical background of therapeutic applications. Conclusion: Hence, results of this study concluded that the ethanolic extract of L. vulgaris has many therapeutic applications such as antimicrobial, antioxidant, and anti-inflammatory activities. SUMMARY Squid ink is very high in a number of important nutrients. It’s particularly high in antioxidants for instance, which as well all know help to protect the cells and the heart against damage from free radicals. In the present study, the squid ink have antioxidant, anti-inflammatory and cytotoxic properties and can be considered as promising the developing the drugs. Abbreviations Used: DPPH: 2,2-diphenyl-1-picrylhydrazyl, FTIR: Fourier-transform infrared spectroscopy, BSA: Bovine Serum Albumin PMID:29333051

Squid-derived chitin oligosaccharides are a chemotactic signal during colonization by Vibrio fischeri.

PubMed

Mandel, Mark J; Schaefer, Amy L; Brennan, Caitlin A; Heath-Heckman, Elizabeth A C; Deloney-Marino, Cindy R; McFall-Ngai, Margaret J; Ruby, Edward G

2012-07-01

Chitin, a polymer of N-acetylglucosamine (GlcNAc), is noted as the second most abundant biopolymer in nature. Chitin serves many functions for marine bacteria in the family Vibrionaceae ("vibrios"), in some instances providing a physical attachment site, inducing natural genetic competence, and serving as an attractant for chemotaxis. The marine luminous bacterium Vibrio fischeri is the specific symbiont in the light-emitting organ of the Hawaiian bobtail squid, Euprymna scolopes. The bacterium provides the squid with luminescence that the animal uses in an antipredatory defense, while the squid supports the symbiont's nutritional requirements. V. fischeri cells are harvested from seawater during each host generation, and V. fischeri is the only species that can complete this process in nature. Furthermore, chitin is located in squid hemocytes and plays a nutritional role in the symbiosis. We demonstrate here that chitin oligosaccharides produced by the squid host serve as a chemotactic signal for colonizing bacteria. V. fischeri uses the gradient of host chitin to enter the squid light organ duct and colonize the animal. We provide evidence that chitin serves a novel function in an animal-bacterial mutualism, as an animal-produced bacterium-attracting synomone.

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

NASA Astrophysics Data System (ADS)

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

2008-10-01

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

Modeling the Effects of Varying the Capacitance, Resistance, Temperature, and Frequency Dependence for HTS Josephson Junctions, DC SQUIDs and DC bi-SQUIDS

DTIC Science & Technology

2014-09-01

junction is a thin layer of insulating material sep- arating two superconductors that is thin enough for electrons to tunnel through. Two Josephson...can sense minute magnetic fields approaching 1015 Tesla. These SQUIDs can be arranged in arrays with different coupling schemes and parameter values to...different material and/or method on the bisecting Josephson junction for high temperature superconductor (HTS) YBa2Cu3O7 (YBCO) bi-SQUIDs. This

Controlling Hysteresis in Superconducting Weak Links and μ-Superconducting Quantum Interference Devices

NASA Astrophysics Data System (ADS)

Kumar, Nikhil; Winkelmann, C. B.; Biswas, Sourav; Courtois, H.; Gupta, Anjan K.

We have fabricated and studied the current-voltage characteristics of a number of niobium film based weak-link devices and μ-SQUIDs showing a critical current and two re-trapping currents. We have proposed a new understanding for the re-trapping currents in terms of thermal instabilities in different portions of the device. We also find that the superconducting proximity effect and the phase-slip processes play an important role in dictating the temperature dependence of the critical current in the non-hysteretic regime. The proximity effect helps in widening the temperature range of hysteresis-free characteristics. Finally we demonstrate control on temperature-range with hysteresis-free characteristics in two ways: 1) By using a parallel shunt resistor in close vicinity of the device, and 2) by reducing the weak-link width. Thus we get non-hysteretic behavior down to 1.3 K temperature in some of the studied devices. We acknowledge the financial support from CSIR, India as well as CNRS-Institute Neel, Grenoble, France.

Molecular identification of anisakid nematodes third stage larvae isolated from common squid ( Todarodes pacificus) in Korea

NASA Astrophysics Data System (ADS)

Setyobudi, Eko; Jeon, Chan-Hyeok; Choi, Kwangho; Lee, Sung Il; Lee, Chung Il; Kim, Jeong-Ho

2013-06-01

The occurrence of Genus Anisakis nematode larvae in marine fishes and cephalopods is epidemiologically important because Anisakis simplex larval stage can cause a clinical disease in humans when infected hosts are consumed raw. Common squid ( Todarodes pacificus) from Korean waters were investigated for anisakid nematodes infection during 2009˜2011. In total, 1,556 larvae were collected from 615 common squids and 732 of them were subsequently identified by PCR-RFLP analysis of ITS rDNA. Depending on the sampling locations, the nematode larvae from common squid showed different prevalence, intensity and species distribution. A high prevalence (P) and mean intensity (MI) of infection were observed in the Yellow Sea (n = 250, P = 86.0%, MI = 5.99 larvae/host) and the southern sea of Korea (n = 126, P = 57.1%, MI = 3.36 larvae/host). Anisakis pegreffii was dominantly found in common squid from the southern sea (127/ 140, 90.7%) and the Yellow Sea (561/565, 98.9%). In contrast, the P and MI of infection were relatively low in the East Sea (n = 239, P = 8.37%, MI = 1.25 larvae/host). A. pegreffii was not found from the East Sea and 52.0% (13/25) of the nematodes were identified as A. simplex. Most of them were found in the body cavity or digestive tract of common squid, which are rarely consumed raw by humans. Considering the differenences in anisakid nematode species distribution and their microhabitat in common squid, it remains unclear whether common squid plays an important role in the epidemiology of human anisakis infection in Korea. Further extensive identification of anisakid nematodes in common squid, with geographical and seasonal information will be necessary.

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.

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

NASA Technical Reports Server (NTRS)

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

1990-01-01

In the Laboratory a high-T(sub c) 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 10 x 10 x 2 mm ceramics pellet a 0.8 mm hole was drilled in which 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.

Food web and fish stock changes in central Chile: comparing the roles of jumbo squid (Dosidicus gigas) predation, the environment, and fisheries

NASA Astrophysics Data System (ADS)

Neira, Sergio; Arancibia, Hugo

2013-10-01

We analyzed recent food web and fish stock changes in the central Chile marine ecosystem, comparing the roles of jumbo squid (Dosidicus gigas) as predator, the environment, and fishing. To accomplish this we used food web modeling and the Ecopath with Ecosim software (EwE). The principal fish stocks have experienced wide decadal fluctuations in the past 30 years, including stock collapses of horse mackerel (Trachurus murphyi) and hake (Merluccius gayi), and there was a large influx of jumbo squid during the mid-2000s. We used two EwE models representing the food web off central Chile to test the hypothesis that predation by jumbo squid has been significant in explaining the dynamics of the main fishing resources and other species in the study area. Results indicate that predation by jumbo squid on fish stocks is lower than that of other predators (e.g. hake) and the fishery. Long-term fluctuations (1978-2004) in the biomass of the main fish stocks (as well as other components of the food web) seem to be related to fishing and to variation in primary production, rather than to predation by jumbo squid alone. Jumbo squid seems to play a role as predator rather than prey in the system, but its impacts are low when compared with the impacts of other predators and fishing. Therefore, we conclude that jumbo squid predation on its prey was not the primary force behind the collapse of important fish stocks off central Chile. Future efforts should be directed to better understanding factors that trigger sudden increases in jumbo squid abundance off central Chile, as well as modeling its trophic impacts.

Characterization of the Bacterial Diversity in Indo-West Pacific Loliginid and Sepiolid Squid Light Organs

PubMed Central

Guerrero-Ferreira, Ricardo; Gorman, Clayton; Chavez, Alba A.; Willie, Shantell

2013-01-01

Loliginid and sepiolid squid light organs are known to host a variety of bacterial species from the family Vibrionaceae, yet little is known about the species diversity and characteristics among different host squids. Here we present a broad-ranging molecular and physiological analysis of the bacteria colonizing light organs in loliginid and sepiolid squids from various field locations of the Indo-West Pacific (Australia and Thailand). Our PCR-RFLP analysis, physiological characterization, carbon utilization profiling, and electron microscopy data indicate that loliginid squid in the Indo-West Pacific carry a consortium of bacterial species from the families Vibrionaceae and Photobacteriaceae. This research also confirms our previous report of the presence of Vibrio harveyi as a member of the bacterial population colonizing light organs in loliginid squid. pyrH sequence data were used to confirm isolate identity, and indicates that Vibrio and Photobacterium comprise most of the light organ colonizers of squids from Australia, confirming previous reports for Australian loliginid and sepiolid squids. In addition, combined phylogenetic analysis of PCR-RFLP and 16S rDNA data from Australian and Thai isolates associated both Photobacterium and Vibrio clades with both loliginid and sepiolid strains, providing support that geographical origin does not correlate with their relatedness. These results indicate that both loliginid and sepiolid squids demonstrate symbiont specificity (Vibrionaceae), but their distribution is more likely due to environmental factors that are present during the infection process. This study adds significantly to the growing evidence for complex and dynamic associations in nature and highlights the importance of exploring symbiotic relationships in which non-virulent strains of pathogenic Vibrio species could establish associations with marine invertebrates. PMID:22885637

Effect of thermal processing and canning on cadmium and lead levels in California market squid: the role of metallothioneins.

PubMed

Galitsopoulou, A; Georgantelis, D; Kontominas, M G

2013-01-01

The effects of two common seafood preparation practices (roasting and industrial canning) on the heavy metal content--cadmium (Cd) and lead (Pb)--of various tissues of California market squid were studied. Emphasis was placed on the role of metallothioneins (MT) in Cd and Pb behaviour during processing. Cd and Pb analysis was conducted by a Zeeman GTA-AAS atomic absorption spectrometry system; MT analysis was performed by a mercury saturation assay. Results showed that Cd levels in the mantle and whole squid were considerably affected by both processing practices, reaching a 240% increase in mantle and a 40% increase in whole squid. Interestingly, Cd behaviour was associated with MT changes during squid processing. On the other hand, Pb content was not affected from either processing or associated with MT content in the raw or processed squid. Therefore, processing operations may affect Cd and Pb content differently due to the specific metal bioaccumulation and chemical features of each heavy metal type.

System having unmodulated flux locked loop for measuring magnetic fields

DOEpatents

Ganther, Jr., Kenneth R.; Snapp, Lowell D [Blue Springs, MO

2006-08-15

A system (10) for measuring magnetic fields, wherein the system (10) comprises an unmodulated or direct-feedback flux locked loop (12) connected by first and second unbalanced RF coaxial transmission lines (16a, 16b) to a superconducting quantum interference device (14). The FLL (12) operates for the most part in a room-temperature or non-cryogenic environment, while the SQUID (14) operates in a cryogenic environment, with the first and second lines (16a, 16b) extending between these two operating environments.

Effect of Selective Co Addition on Magnetic Properties of Nd2(FeCo)14B/alpha-Fe Nanocomposite Magnets

DTIC Science & Technology

2012-12-13

pressure of ∼2.5 GPa. The final bulk magnets having dimensions Ø6 mm × 1.5 mm were characterized for morphology and the crystalline structure using scanning... Magnetic properties were measured with a superconducting quantum interference device (SQUID) magnetometer with a maximum applied field of 70 kOe. To...calculate the true energy product (BH)max of the bulk sample, we determined the demagnetization factor experimentally as described in [9]. Figure 1 shows

Prospects for small cryocoolers. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Radebaugh, R.

1982-01-01

Small cryocoolers are commonly used in the areas of infrared detection, satellite communication, and cryopumps. Some emerging application areas deal with SQUID and Josephson junction devices, which require temperatures of about 8 K or below. The need for high reliability in these small cryocoolers has dictated the use of regenerative-cycle machines, but such machines are presently limited to temperatures above about 8 K. This paper discusses some of the research being done to improve reliability, decrease noise, and reduce the low-temperature limit of small cryocoolers.

Novel Polymers Containing Metal Ligands in the Side Chain

DTIC Science & Technology

2012-10-01

10 2011): 0. doi: 10.1021/bm2010142 2012/10/01 15:35:02 10 Jun Cui, Melissa A. Lackey, Ahmad E. Madkour , Erika M. Saffer, David M. Griffin, Surita R...values for the linear fits are around 0.98. [M] denotes the monomer concentration. M- H measurement. If the RTF behavior of the previously...magnetization as a function of the applied field (M- H ) was measured at room temperature by a superconducting quantum interference device (SQUID) for all of

Realizing various approximate quantum cloning with XY-type exchange interactions of flux qubits

NASA Astrophysics Data System (ADS)

Li, Na; Ye, Liu

2014-03-01

In this paper, we realize all kinds of 1 → 2 approximate quantum cloning, including optimal 1 → 2 symmetric (or asymmetric) universal quantum cloning (UQC) and phase-covariant cloning (PCC), symmetric economical phase-covariant cloning (EPCC) and real state quantum cloning, with the XY-type exchange interactions of the flux qubits which are coupled by dc superconducting quantum interference devices (SQUIDs). It is shown that our schemes can be realized with the current experimental technology.

Experimental formation of a fractional vortex in a superconducting bi-layer

NASA Astrophysics Data System (ADS)

Tanaka, Y.; Yamamori, H.; Yanagisawa, T.; Nishio, T.; Arisawa, S.

2018-05-01

We report the experimental formation of a fractional vortex generated by using a thin superconducting bi-layer in the form of a niobium bi-layer, observed as a magnetic flux distribution image taken by a scanning superconducting quantum interference device (SQUID) microscope. Thus, we demonstrated that multi-component superconductivity can be realized by an s-wave conventional superconductor, because, in these superconductors, the magnetic flux is no longer quantized as it is destroyed by the existence of an inter-component phase soliton (i-soliton).

Analog cosmological particle generation in a superconducting circuit

NASA Astrophysics Data System (ADS)

Tian, Zehua; Jing, Jiliang; Dragan, Andrzej

2017-06-01

We propose the use of a waveguidelike transmission line based on direct-current superconducting quantum interference devices (dc-SQUID) and demonstrate that the node flux in this transmission line behaves in the same way as quantum fields in an expanding (or contracting) universe. We show how to detect the analog cosmological particle generation and analyze its feasibility with current circuit quantum electrodynamics (cQED) technology. Our setup in principle paves a new way for the exploration of analog quantum gravitational effects.

Ultrasensitive Superconducting Transition Edge Sensors Based On Electron-Phonon Decoupling

NASA Technical Reports Server (NTRS)

Jethava, Nikhil; Chervenak, James; Brown, Ari-David; Benford, Dominic; Kletetschka, Gunther; Mikula, Vilem; U-yen, Kongpop

2011-01-01

We have successfully fabricated the superconducting transition edge sensor (TES), bolometer technology that centers on the use of electron-phonon decoupling (EPD) to thermally isolate the bolometer. Along with material characterization for large format antenna coupled bolometer arrays, we present the initial test results of bolometer based on EPD designed for THz detection. We have selected a design approach that separates the two functions of photon absorption and temperature measurement, allowing separate optimization of the performance of each element. We have integrated Molybdenum/Gold (Mo/Au) bilayer TES and ion assisted thermally evaporated (IAE) Bismuth (Bi) films as radiation absorber coupled to a low-loss microstripline from Niobium (Nb) ground plane to a twin-slot antenna structure. The thermal conductance and the time constant of these devices have been measured, and are consistent with our calculations. The device exhibits a single time constant at 0.1 K of approx.160 IlS, which is compatible with readout by a high-bandwidth single SQUID or a time domain SQUID multiplexer. The effects of thermal conductance and electrothermal feedback are major determinants of the time constant, but the electronic heat capacity also plays a major role. The NEP achieved in the device described above is 2.5x10(exp -17)W(gamma)Hz. Our plan is to demonstrate a reduction of the volume in the superconducting element to 5 microns x 5 microns in films of half the thickness at Tc = 60mK. By calculation, this new geometry corresponds to an NEP reduction of two orders of magnitude to 2.5x10(exp -19)W/(gamma)Hz, with a time constant of 130/ls.

NIS tunnel junction as an x-ray photon sensor

NASA Astrophysics Data System (ADS)

Azgui, Fatma; Mears, Carl A.; Labov, Simon E.; Frank, Matthias A.; Sadoulet, Bernard; Brunet, E.; Hiller, Lawrence J.; Lindeman, Mark A.; Netel, Harrie

1995-09-01

This work presents the first results of our development of normal-insulating-superconducting tunnel junctions used as energy dispersive detectors for low energy particles. The device described here is a Ag/Al(subscript 2)O(subscript 3)/Al tunnel junction of area 1.5 multiplied by 10(superscript 4) micrometer squared with thicknesses of 200 nm for the normal Ag strip and 100 nm for the superconducting Al film. Two different high-speed SQUID systems manufactured by quantum magnetics and HYPRES, respectively, were used for the readout of this device. At 80 mK bath temperature we obtained an energy resolution DeltaE(subscript FWHM) equals 250 eV for 5.89 keV x rays absorbed directly in the normal metal. This energy resolution appears to be limited in large part by the observed strong position dependence of the device response.

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.

MEMS-based gradiometer for the complete characterization of Martian magnetic environment

NASA Astrophysics Data System (ADS)

Mesa, Jose Luis; Ciudad, David; McHenry, Michael E.; Aroca, Claudio; Díaz-Michelena, Marina

2013-04-01

The in-situ determination of the Martian magnetic field is one of the most important and ambitious objectives in Mars exploration, because its implications in paleomagnetism, tectonics and mineral determination. To place sensors on Mars is a complicated task, due to the extreme conditions of the planet surface and also because of the relative low budget devoted to this kind of instrument: low power, mass, volume and the need to operate in a magnetically noise environment. A complete and accurate measurement of the magnetic environment includes the determination of both magnitude and gradient of the magnetic field (B). There are many developments of magnetometers with the characteristics mentioned before [2], but the question about gradient is not that well solved and most gradient sensors are based on a couple of magnetometers separated a certain distance [2, 3]. The aim of this abstract is to introduce a new MEMS based robust gradiometer for the point measurement of the field gradient with the ultimate goal to perform in situ measurement on Mars and shed some light in the magnetic anomalies explanation of the Red Planet. Since in some conditions ?ׯB = 0, we assume knowing six of the nine components is sufficient to reconstruct entirely the magnetic field gradient. The device proposed consists of a set of six cantilevers to measure these six components (with resolution in the order of 1 nT/mm) combined either with another miniaturized and more accurate magnetometer (with resolution below the nT) for the measurement of the field vector. Every component system consists of a cantilever with an appropriate geometry, an excitation coil and a mechanism to generate a field gradient. The cantilevers are made of piezoelectric material (bimorph, with two piezoelectric layers) covered by a soft ferromagnetic material (of Iron-Nickel base). Is explained below the working principle for one component. When the excitation system generates an alternating magnetic field (enough to saturate) along the width of the cantilever, the ferromagnetic material is alternatively saturated in both directions along the cantilever's width. Under the presence of a magnetic field gradient in the normal direction to the plane of the cantilever, the ferromagnetic material experiments a force, making the cantilever vibrate. This vibration generates an electric signal, given that when the cantilever vibrates, the piezoelectric layers stretches and contracts, so it sets a voltage difference. The current system with dimensions in the order of mm is run at its resonant frequency. In the presence of an external magnetic field gradient, the vibration frequency changes. The external gradient can be easily measured by means of the measurement of the frequency shift. References: [1] Acuña, M.H.: Space-based magnetometers, Rev. Sci. Instrum., 73, 3717-3736, doi: 10.1063/1.1510570, Nov 2002. [2] Merayo, J.M.G.; Brauer, P.; Primdahl, F.: Triaxial fluxgate gradiometer of high stability and linearity, Sensor Actuat A-Phys., 120, 71-77, doi: 10.1016/j.sna.2004.11.014, Apr 2005. [3] Lucas, I.; Michelena, M.D.;del Real, R.P.; de Manuel, V.; Plaza, J.A. 2; Duch, M.; Esteve, J; Guerrero, H.: A New Single-Sensor Magnetic Field Gradiometer, Sens. Lett., 7, 563-570, doi: 10.1166/sl.2009.1110, Aug 2009.

Tuning the Stiffness Balance Using Characteristic Frequencies as a Criterion for a Superconducting Gravity Gradiometer.

PubMed

Liu, Xikai; Ma, Dong; Chen, Liang; Liu, Xiangdong

2018-02-08

Tuning the stiffness balance is crucial to full-band common-mode rejection for a superconducting gravity gradiometer (SGG). A reliable method to do so has been proposed and experimentally tested. In the tuning scheme, the frequency response functions of the displacement of individual test mass upon common-mode accelerations were measured and thus determined a characteristic frequency for each test mass. A reduced difference in characteristic frequencies between the two test masses was utilized as the criterion for an effective tuning. Since the measurement of the characteristic frequencies does not depend on the scale factors of displacement detection, stiffness tuning can be done independently. We have tested this new method on a single-component SGG and obtained a reduction of two orders of magnitude in stiffness mismatch.

77 FR 22678 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-17

.... 110707371-2136-02] RIN 0648- XB145 Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Closure of the Trimester 1 Longfin Squid Fishery AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), Commerce. ACTION...

Natural mortality estimation and rational exploitation of purpleback flying squid Sthenoteuthis oualaniensis in the southern South China Sea

NASA Astrophysics Data System (ADS)

Wang, Xuehui; Qiu, Yongsong; Zhang, Peng; Du, Feiyan

2017-07-01

Based on the biological data of purpleback flying squid ( Sthenoteuthis oualaniensis) collected by light falling-net in the southern South China Sea (SCS) during September to October 2012 and March to April 2013, growth and mortality of `Medium' and `Dwarf' forms of squid are derived using the Powell-Wetherall, ELEFAN methods and length-converted catch curves (FiSAT package). Given a lack of commercial exploitation, we assume total mortality to be due entirely to natural mortality. We estimate these squid have fast growth, with growth coefficients ( k) ranging from 1.42 to 2.39, and high natural mortality ( M), with estimates ranging from 1.61 to 2.92. To sustainably exploit these squid stocks, yield per recruitment based on growth and natural mortality was determined using the Beverton-Holt dynamic pool model. We demonstrate squid stocks could sustain high fishing mortality and low ages at first capture, with an optimal fishing mortality >3.0, with the optimal age at first capture increased to 0.4-0.6 years when fishing mortality approached optimal levels. On the basis of our analyses and estimates of stock biomass, we believe considerable potential exists to expand the squid fishery into the open SCS, relieving fishing pressure on coastal waters.

Material properties of Pacific hake, Humboldt squid, and two species of myctophids in the California Current.

PubMed

Becker, Kaylyn N; Warren, Joseph D

2015-05-01

Material properties of the flesh from three fish species (Merluccius productus, Symbolophorus californiensis, and Diaphus theta), and several body parts of the Humboldt squid (Dosidicus gigas) collected from the California Current ecosystem were measured. The density contrast relative to seawater varied within and among taxa for fish flesh (0.9919-1.036), squid soft body parts (mantle, arms, tentacle, braincase, eyes; 1.009-1.057), and squid hard body parts (beak and pen; 1.085-1.459). Effects of animal length and environmental conditions on nekton density contrast were investigated. The sound speed contrast relative to seawater varied within and among taxa for fish flesh (0.986-1.027) and Humboldt squid mantle and braincase (0.937-1.028). Material properties in this study are similar to values from previous studies on species with similar life histories. In general, the sound speed and density of soft body parts of fish and squid were 1%-3% and 1%-6%, respectively, greater than the surrounding seawater. Hard parts of the squid were significantly more dense (6%-46%) than seawater. The material properties reported here can be used to improve target strength estimates from acoustic scattering models, which could increase the accuracy of biomass estimates from acoustic surveys for these nekton.

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.

Identification of four squid species by quantitative real-time polymerase chain reaction.

PubMed

Ye, Jian; Feng, Junli; Liu, Shasha; Zhang, Yanping; Jiang, Xiaona; Dai, Zhiyuan

2016-02-01

Squids are distributed worldwide, including many species of commercial importance, and they are often made into varieties of flavor foods. The rapid identification methods for squid species especially their processed products, however, have not been well developed. In this study, quantitative real-time PCR (qPCR) systems based on specific primers and TaqMan probes have been established for rapid and accurate identification of four common squid species (Ommastrephes bartramii, Dosidicus gigas, Illex argentinus, Todarodes pacificus) in Chinese domestic market. After analyzing mitochondrial genes reported in GenBank, the mitochondrial cytochrome b (Cytb) gene was selected for O. bartramii detection, cytochrome c oxidase subunit I (COI) gene for D. gigas and T. Pacificus detection, ATPase subunit 6 (ATPase 6) gene for I. Argentinus detection, and 12S ribosomal RNA (12S rDNA) gene for designing Ommastrephidae-specific primers and probe. As a result, all the TaqMan systems are of good performance, and efficiency of each reaction was calculated by making standard curves. This method could detect target species either in single or mixed squid specimen, and it was applied to identify 12 squid processed products successfully. Thus, it would play an important role in fulfilling labeling regulations and squid fishery control. Copyright © 2016 Elsevier Ltd. All rights reserved.

Investigation of the Vortex States of Sr2RuO4-Ru Eutectic Microplates Using DC-SQUIDs

NASA Astrophysics Data System (ADS)

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

2017-11-01

We investigated the magnetic properties of a Sr2RuO4-Ru eutectic microplate containing a single Ru-inclusion using micrometer-sized DC-SQUIDs (direct-current superconducting quantum interference devices). A phase frustration at the interface between chiral p-wave superconducting Sr2RuO4 and s-wave superconducting Ru is expected to cause novel magnetic vortex states such as the spontaneous Ru-center vortex under zero magnetic field [as reported by H. Kaneyasu and M. Sigrist, J. Phys. Soc. Jpn. 79, 053706 (2010)]. Our experimental results show no positive evidence for such a spontaneous vortex state. However, in an applied field, an abrupt change in the magnetic flux distribution was observed at a superconducting transition of Ru. The flux distribution is clarified by comparing our experimental results with electromagnetic field simulations in our sample geometry. We discuss the transition of the vortex states and the superconducting coupling at the Sr2RuO4/Ru interface.

Synthesis, characterization, and growth mechanism of motifs of ultrathin cobalt-substituted NaFeSi 2O 6 nanowires

DOE PAGES

Lewis, Crystal S.; Moronta, Dominic; Terban, Maxwell W.; ...

2017-12-12

In this report, we have synthesized and structurally characterized nanowire bundles of cobalt-substituted pyroxenes, similar to the crystal structure of aegirine (i.e. Co-substituted XYSi 2O 6 with X and Y referring to metallic elements such as but not limited to Co, Na, and Fe), using a readily scalable hydrothermal technique. We then propose a growth mechanism for these bundles, based on detailed time and temperature dependent studies as well as complementary control experiments, particularly reactions in the absence of either 3-aminopropyltriethoxysilane (APTES) or sodium hydroxide (NaOH), via a transmission electron microscopy visualization study. Moreover, these nanowire bundles were probed formore » their magnetic properties and chemical composition using superconducting quantum interference device (SQUID) measurements, X-ray diffraction, and pair distribution function analysis, respectively. Specifically, SQUID measurement observations highlighted that these bundles evince (i) unique and interesting super-paramagnetic properties at 5 K that are consistent with that of our previously published ~2 nm ultra-small nanoparticles as well as (ii) paramagnetic behavior at 300 K.« less

Experiments with d-wave Superconductors

NASA Astrophysics Data System (ADS)

Mannhart, J.; Hilgenkamp, H.; Hammerl, G.; Schneider, C. W.

2003-10-01

The predominant dx2-y2-wave pairing-symmetry of most high-Tc, superconductors provides the opportunity to fabricate Josephson junction circuits in which part of the junctions are biased by a phase difference of the superconducting order parameter of π. To explore the road to such π-electronics, we have fabricated and studied all-high-Tc dc superconducting quantum interference devices (dc SQUIDs) realized with thin film technology, of which the Josephson junctions consist of one standard junction and one junction with a π-phase shift. These π-SQUIDs provide clear evidence of the dx2-y2-wave symmetry of the order parameter, the amount of complex admixtures of other symmetry components being undetectably small. This seems to contradict other experiments, the results of which have been presented as evidence for an s-wave order parameter or for complex admixtures. Possible solutions to resolve this apparent contradiction are presented. In particular it is pointed out that even in the bulk of a superconductor the order parameter symmetry (the admixture of various symmetry components) may be spatially dependent.

Functional Description of Read-out Electronics for Time-Domain Multiplexed Bolometers for Millimeter and Sub-millimeter Astronomy

NASA Astrophysics Data System (ADS)

Battistelli, E. S.; Amiri, M.; Burger, B.; Halpern, M.; Knotek, S.; Ellis, M.; Gao, X.; Kelly, D.; Macintosh, M.; Irwin, K.; Reintsema, C.

2008-05-01

We have developed multi-channel electronics (MCE) which work in concert with time-domain multiplexors developed at NIST, to control and read signals from large format bolometer arrays of superconducting transition edge sensors (TESs). These electronics were developed as part of the Submillimeter Common-User Bolometer Array-2 (SCUBA2 ) camera, but are now used in several other instruments. The main advantages of these electronics compared to earlier versions is that they are multi-channel, fully programmable, suited for remote operations and provide a clean geometry, with no electrical cabling outside of the Faraday cage formed by the cryostat and the electronics chassis. The MCE is used to determine the optimal operating points for the TES and the superconducting quantum interference device (SQUID) amplifiers autonomously. During observation, the MCE execute a running PID-servo and apply to each first stage SQUID a feedback signal necessary to keep the system in a linear regime at optimal gain. The feedback and error signals from a ˜1000-pixel array can be written to hard drive at up to 2 kHz.

Scanning SQUID microscopy of a ferromanganese crust from the northwestern Pacific: Submillimeter scale magnetostratigraphy as a new tool for age determination and mapping of environmental magnetic parameters

NASA Astrophysics Data System (ADS)

Noguchi, A.; Oda, H.; Yamamoto, Y.; Usui, A.; Sato, M.; Kawai, J.

2017-06-01

Ferromanganese crusts record long-term deep-sea environmental changes. Thus, providing their reliable high-resolution age models is important. We applied a magnetostratigraphic technique to estimate the growth rate of a ferromanganese crust using scanning SQUID (superconducting quantum interference device) microscope (SSM). SSM is designed to map the magnetic field across thin sections with submillimeter resolution. The crust sample was taken from the Takuyo-Daigo Seamount, northwestern Pacific, and recorded a limited supply of dust and sediment from continents. After drift correction and removal of spike noises, the magnetic field values were stacked within the areas of high signal-to-noise ratios. By correlating the obtained profiles with a standard geomagnetic polarity timescale, we obtained an average growth rate of 3.37 ± 0.06 mm/Ma, which is consistent with that obtained by 10Be/9Be geochronology (2.93 ± 0.15 mm/Ma). S ratio mapping shows low values after 3 Ma, associated with voids between columnar structures.

Synthesis, characterization, and growth mechanism of motifs of ultrathin cobalt-substituted NaFeSi 2O 6 nanowires

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lewis, Crystal S.; Moronta, Dominic; Terban, Maxwell W.

In this report, we have synthesized and structurally characterized nanowire bundles of cobalt-substituted pyroxenes, similar to the crystal structure of aegirine (i.e. Co-substituted XYSi 2O 6 with X and Y referring to metallic elements such as but not limited to Co, Na, and Fe), using a readily scalable hydrothermal technique. We then propose a growth mechanism for these bundles, based on detailed time and temperature dependent studies as well as complementary control experiments, particularly reactions in the absence of either 3-aminopropyltriethoxysilane (APTES) or sodium hydroxide (NaOH), via a transmission electron microscopy visualization study. Moreover, these nanowire bundles were probed formore » their magnetic properties and chemical composition using superconducting quantum interference device (SQUID) measurements, X-ray diffraction, and pair distribution function analysis, respectively. Specifically, SQUID measurement observations highlighted that these bundles evince (i) unique and interesting super-paramagnetic properties at 5 K that are consistent with that of our previously published ~2 nm ultra-small nanoparticles as well as (ii) paramagnetic behavior at 300 K.« less

Opportunistic acoustic recordings of (potential) orangeback flying squid Sthenoteuthis pteropus in the Central Eastern Atlantic

NASA Astrophysics Data System (ADS)

Peña, Marian; Villanueva, Roger; Escánez, Alejandro; Ariza, Alejandro

2018-03-01

Squids are fast swimmers that are difficult to catch by nets and to record with echosounders in the open ocean. A rare detection of orangeback flying squid Sthenoteuthis pteropus in the Central Eastern Atlantic Ocean off the coast of Senegal was accomplished during the MAFIA oceanographic survey carried out between Brazil and the Canary Islands in April 2015. Although net sampling did not yield any subadult or adult individuals, dozens were visually detected from the vessel jumping out of the water at night and displaying their characteristic dorsal photophore patch. A few squids were caught with fishing lines and identified at the species level. The acoustic echograms revealed distinctive previously unobserved acoustic echotraces that seemed to be caused by those squids, which were the only new species detected at that station (over a bottom depth ranging from 4010 to 5215 m, between 10° 45‧ N 22° 41‧ W and 10° 53‧ N 22° 40‧ W). The acoustic response and swimming behaviour shown by those echotraces reinforced this hypothesis. The (potentially) squid recordings dove rapidly (0.19 m/s to 0.48 m/s) from around 10 m below the mesopelagic fish layer, which had migrated to the subsurface at night (35 m depth), to depths of 70-95 m, and swam upward, apparently attacking fish from below. The morning squid migration to deeper waters (250-300 m) was also recorded acoustically. Downward movements of squid swimming at speeds of 0.22 m/s were calculated from the echogram, while the mesopelagic migrating fish swam at 0.27 m/s reaching 250 m depth. Sv120 - Sv38 averaged 2.7 ± 3.2 dB for the squid echotraces while the mesopelagic layer showed values of -8.8 ± 0.9 dB. These ranges agreed with values in the literature and from theoretical models. This study provides more insight into the migrating behaviour of oceanic squids, a species group that is poorly represented in the acoustic literature due to challenges in studying them.

Extreme plasticity in life-history strategy allows a migratory predator (jumbo squid) to cope with a changing climate.

PubMed

Hoving, Henk-Jan T; Gilly, William F; Markaida, Unai; Benoit-Bird, Kelly J; -Brown, Zachary W; Daniel, Patrick; Field, John C; Parassenti, Liz; Liu, Bilin; Campos, Bernardita

2013-07-01

Dosidicus gigas (jumbo or Humboldt squid) is a semelparous, major predator of the eastern Pacific that is ecologically and commercially important. In the Gulf of California, these animals mature at large size (>55 cm mantle length) in 1-1.5 years and have supported a major commercial fishery in the Guaymas Basin during the last 20 years. An El Niño event in 2009-2010, was accompanied by a collapse of this fishery, and squid in the region showed major changes in the distribution and life-history strategy. Large squid abandoned seasonal coastal-shelf habitats in 2010 and instead were found in the Salsipuedes Basin to the north, an area buffered from the effects of El Niño by tidal upwelling and a well-mixed water column. The commercial fishery also relocated to this region. Although large squid were not found in the Guaymas Basin from 2010 to 2012, small squid were abundant and matured at an unusually small mantle-length (<30 cm) and young age (approximately 6 months). Juvenile squid thus appeared to respond to El Niño with an alternative life-history trajectory in which gigantism and high fecundity in normally productive coastal-shelf habitats were traded for accelerated reproduction at small size in an offshore environment. Both small and large mature squid, were present in the Salsipuedes Basin during 2011, indicating that both life- history strategies can coexist. Hydro-acoustic data, reveal that squid biomass in this study area nearly doubled between 2010 and 2011, primarily due to a large increase in small squid that were not susceptible to the fishery. Such a climate-driven switch in size-at-maturity may allow D. gigas to rapidly adapt to and cope with El Niño. This ability is likely to be an important factor in conjunction with longerterm climate-change and the potential ecological impacts of this invasive predator on marine ecosystems. © 2013 Blackwell Publishing Ltd.

Relationships between morphometrical properties and the texture of an extrusion-expanded snack made from squid mantle (Dosidicus gigas).

PubMed

Valenzuela-Lagarda, José Luis; García-Armenta, Evangelina; Pacheco-Aguilar, Ramón; Gutiérrez-Dorado, Roberto; Mazorra-Manzano, Miguel Ángel; Lugo-Sánchez, María Elena; Muy-Rangel, María Dolores

2018-01-24

The giant squid (Dosidicus gigas) is a species of commercial interest as a source of protein, and it can be developed into ready-to-eat food products, including expanded extrusion snacks (EES). EES are prepared primarily from starch; however, adding animal protein increases the nutritional contents. The objective of this study was to evaluate the effect of the protein-carbohydrate interactions on the physical and morphological characteristics of an EES made of squid mantle and potato-corn flour. The independent variable was the squid mantle content (40, 60, 80, and 100%) and two controls (0 1  = 100% potato, 0 2  = 100% corn). The expansion rate (ER) of the sample is significantly minor (p < .5) when the squid mantle content increases ER = 2.0, 1.8 1.4 to 40, 60, and 80%, respectively. In samples with more protein, crispness and crunchiness were reduced, whereas the hardness increased. Digital imaging analysis indicated that the interaction between protein and starch causes significant morphometric changes to the fractal dimension (2.665-2.739) and lacunarity (0.61-1.29). The results showed that it is possible to incorporate up to 60% squid mantle to prepare EES that possess texture and morphometric characteristics competitive in reported studies with snacks usually incorporating flours, corn, and wheat in the formulations. The giant squid is a very attractive species because its meat has low caloric intake, high protein content, and is an important source of omega 3 fatty acids. Despite the desirable qualities of the squid meat its consumption is very low due to the low diffusion of the properties of its meat, acid, and ammoniacal flavor, rigid texture that requires prolonged cooking times and lack of alternatives of consumption. In Mexico, this type of squid is mainly destined for export as frozen mantle and products with little added value, which generates little economic benefit. Therefore, the results of this research may be of interest to the squid processing industry, which demands new forms of consumption of this marine species to increase their commercialization and added value. © 2018 Wiley Periodicals, Inc.

Multiple sensory modalities used by squid in successful predator evasion throughout ontogeny.

PubMed

York, Carly A; Bartol, Ian K; Krueger, Paul S

2016-09-15

Squid rely on multiple sensory systems for predator detection. In this study we examine the role of two sensory systems, the lateral line analogue and vision, in successful predator evasion throughout ontogeny. Squid Doryteuthis pealeii and Lolliguncula brevis were recorded using high-speed videography in the presence of natural predators under light and dark conditions with their lateral line analogue intact or ablated via a pharmacological technique. Paralarval squid showed reduced escape responses when ablated; however, no differences were found between light and dark conditions in non-ablated paralarvae, as was previously shown in juveniles and adults, indicating that the lateral line analogue is integral for predator detection early in life. However, vision does play a role in survival because ablated squid in dark conditions had lower levels of survival than all other treatments. Throughout ontogeny, squid oriented themselves anteriorly towards the oncoming predator, maximizing sensory input to the lateral line analogue system and providing better positioning for tail-first escape jetting, the preferred escape mode. Ablated juveniles and adults had lower response times, escape velocities and peak acceleration than non-ablated individuals, indicating that the lateral line analogue enables squid to respond quicker and with more powerful jets to a predator and maximize escape success. Our findings reveal that the lateral line analogue plays a role in predator detection and successful escape response at the earliest life stages, and continues to contribute to successful evasion by aiding visual cues in juvenile and adult squid. © 2016. Published by The Company of Biologists Ltd.

Interannual and seasonal variability of winter-spring cohort of neon flying squid abundance in the Northwest Pacific Ocean during 1995-2011

NASA Astrophysics Data System (ADS)

Yu, Wei; Chen, Xinjun; Yi, Qian

2016-06-01

The neon flying squid, Ommastrephes bartramii, is a species of economically important cephalopod in the Northwest Pacific Ocean. Its short lifespan increases the susceptibility of the distribution and abundance to the direct impact of the environmental conditions. Based on the generalized linear model (GLM) and generalized additive model (GAM), the commercial fishery data from the Chinese squid-jigging fleets during 1995 to 2011 were used to examine the interannual and seasonal variability in the abundance of O. bartramii, and to evaluate the influences of variables on the abundance (catch per unit effort, CPUE). The results from GLM suggested that year, month, latitude, sea surface temperature (SST), mixed layer depth (MLD), and the interaction term ( SST×MLD) were significant factors. The optimal model based on GAM included all the six significant variables and could explain 42.43% of the variance in nominal CPUE. The importance of the six variables was ranked by decreasing magnitude: year, month, latitude, SST, MLD and SST×MLD. The squid was mainly distributed in the waters between 40°N and 44°N in the Northwest Pacific Ocean. The optimal ranges of SST and MLD were from 14 to 20°C and from 10 to 30 m, respectively. The squid abundance greatly fluctuated from 1995 to 2011. The CPUE was low during 1995-2002 and high during 2003-2008. Furthermore, the squid abundance was typically high in August. The interannual and seasonal variabilities in the squid abundance were associated with the variations of marine environmental conditions and the life history characteristics of squid.

Recent achievements in MgB 2 physics and applications: A large-area SQUID magnetometer and point-contact spectroscopy measurements

NASA Astrophysics Data System (ADS)

Gonnelli, R. S.; Daghero, D.; Calzolari, A.; Ummarino, G. A.; Tortello, M.; Stepanov, V. A.; Zhigadlo, N. D.; Rogacki, K.; Karpinski, J.; Portesi, C.; Monticone, E.; Mijatovic, D.; Veldhuis, D.; Brinkman, A.

2006-03-01

In the first part of the present paper we discuss the fabrication and the characterization of an MgB2-based SQUID magnetometer with a directly coupled large-area pick-up loop, made on an MgB2 film deposited by an all in situ technique. The coarse structure of the SQUID was defined by optical lithography and Ar-ion milling, while the two nanobridges acting as weak links in the superconducting loop were made by focused ion beam (FIB) milling. The device was characterized at different temperatures and showed Josephson quantum interference up to 20 K as well as a noise level already compatible with the recording of an adult magnetocardiogram. In the second part, concerning the fundamental physics of MgB2, we present the results of very recent point-contact measurements on Mg1-xMnxB2 single crystals with 34.1 ⩾ Tc ⩾ 13.3 K (i.e. 0.37% ⩽ x ⩽ 1.5%). The experimental conductance curves were fitted with the generalized two-band BTK model and their behaviour in magnetic fields was studied to check if both the order parameters (OPs) of the σ and π bands were present in the whole doping range. The dependence of the OPs (evaluated through the fit) on the Andreev critical temperature of the junctions is analyzed in the framework of the two-band Eliashberg theory by including the effects of magnetic impurities. The results give an evidence of a dominant effect of the magnetic impurities on the σ-band channel.

Demonstration of a scalable frequency-domain readout of metallic magnetic calorimeters by means of a microwave SQUID multiplexer

NASA Astrophysics Data System (ADS)

Kempf, Sebastian; Wegner, Mathias; Fleischmann, Andreas; Gastaldo, Loredana; Herrmann, Felix; Papst, Maximilian; Richter, Daniel; Enss, Christian

2017-01-01

We report on the first demonstration of a scalable GHz frequency-domain readout of metallic magnetic calorimeters (MMCs) using a 64 pixel detector array that is read out by an integrated, on-chip microwave SQUID multiplexer. The detector array is optimized for detecting soft X-ray photons and the multiplexer is designed to provide a signal rise time τrise<400 ns and an intrinsic energy sensitivity ɛ <30 h . This results in an expected energy resolution Δ EFWHM <10 eV . We measured a signal rise time τrise as low as 90 ns and an energy resolution Δ EFWHM as low as 50 eV for 5.9 keV photons. The rise time is about an order of magnitude faster compared to other multiplexed low-temperature microcalorimeters and close to the intrinsic value set by the coupling between electron and spins. The energy resolution is degraded with respect to our design value due to a rather low intrinsic quality factor of the microwave resonators that is caused by the quality of the Josephson junction of the associated rf-SQUID as well as an elevated chip temperature as compared to the heat bath. Though the achieved energy resolution is not yet compatible with state-of-the-art single-channel MMCs, this demonstration of a scalable readout approach for MMCs in combination with the full understanding of the device performance showing ways how to improve represents an important milestone for the development of future large-scale MMC detector arrays.

Asymmetric nanowire SQUID: Linear current-phase relation, stochastic switching, and symmetries

NASA Astrophysics Data System (ADS)

Murphy, A.; Bezryadin, A.

2017-09-01

We study nanostructures based on two ultrathin superconducting nanowires connected in parallel to form a superconducting quantum interference device (SQUID). The measured function of the critical current versus magnetic field, IC(B ) , is multivalued, asymmetric, and its maxima and minima are shifted from the usual integer and half integer flux quantum points. We also propose a low-temperature-limit model which generates accurate fits to the IC(B ) functions and provides verifiable predictions. The key assumption of our model is that each wire is characterized by a sample-specific critical phase ϕC defined as the phase difference at which the supercurrent in the wire is the maximum. For our nanowires ϕC is much greater than the usual π /2 , which makes a qualitative difference in the behavior of the SQUID. The nanowire current-phase relation is assumed linear, since the wires are much longer than the coherence length. The model explains single-valuedness regions where only one vorticity value nv is stable. Also, it predicts regions where multiple vorticity values are stable because the Little-Parks (LP) diamonds, which describe the region of stability for each winding number nv in the current-field diagram, can overlap. We also observe and explain regions in which the standard deviation of the switching current is independent of the magnetic field. We develop a technique that allows a reliable detection of hidden phase slips and use it to determine the boundaries of the LP diamonds even at low currents where IC(B ) is not directly measurable.

50 CFR 648.124 - Scup commercial season and commercial fishery area restrictions.

Code of Federal Regulations, 2012 CFR

2012-10-01

... vessels in the Southern Gear Restricted Area that are fishing for or in possession of the following non-exempt species: Longfin squid; black sea bass; and silver hake (whiting). (b) Northern Gear Restricted... are fishing for, or in possession of, the following non-exempt species: Longfin squid squid; black sea...

50 CFR 648.124 - Scup commercial season and commercial fishery area restrictions.

Code of Federal Regulations, 2013 CFR

2013-10-01

... vessels in the Southern Gear Restricted Area that are fishing for or in possession of the following non-exempt species: Longfin squid; black sea bass; and silver hake (whiting). (b) Northern Gear Restricted... are fishing for, or in possession of, the following non-exempt species: Longfin squid squid; black sea...

50 CFR 648.124 - Scup commercial season and commercial fishery area restrictions.

Code of Federal Regulations, 2014 CFR

2014-10-01

... vessels in the Southern Gear Restricted Area that are fishing for or in possession of the following non-exempt species: Longfin squid; black sea bass; and silver hake (whiting). (b) Northern Gear Restricted... are fishing for, or in possession of, the following non-exempt species: Longfin squid squid; black sea...

Partial characterization of an effluent produced by cooking of Jumbo squid (Dosidicus gigas) mantle muscle.

PubMed

Rosas-Romero, Zaidy G; Ramirez-Suarez, Juan C; Pacheco-Aguilar, Ramón; Lugo-Sánchez, Maria E; Carvallo-Ruiz, Gisela; García-Sánchez, Guillermina

2010-01-01

Jumbo squid (Dosidicus gigas) mantle muscle was cooked simulating industrial procedures (95 degrees C x 25 min, 1.2:5 muscle:water ratio). The effluent produced was analyzed for chemical and biochemical oxygen demands (COD and BOD(5), respectively), proximate analysis, flavor-related compounds (free amino acids, nucleotides and carbohydrates) and SDS-PAGE. The COD and BOD(5) exhibited variation among samplings (N=3) (27.4-118.5 g O(2)/L for COD and 11.3-26.7 g O(2)/L for BOD(5)). The effluent consisted of 1% total solids, 75% of which represented crude protein. Sixty percent of the total free amino acid content, which imparts flavor in squid species, corresponded to glutamic acid, serine, glycine, arginine, alanine, leucine and lysine. The nucleotide concentration followed this order, Hx>ADP>AMP>ATP>IMP>HxR. The variation observed in the present work was probably due to physiological maturity differences among the squid specimens (i.e., juvenile versus mature). Solids present in squid cooking effluent could be recovered and potentially used as flavor ingredients in squid-analog production by the food industry.

Integration of a Cryocooler into a SQUID Magnetospinography System for Reduction of Liquid Helium Consumption

NASA Astrophysics Data System (ADS)

Adachi, Yoshiaki; Oyama, Daisuke; Kawai, Jun; Ogata, Hisanao; Uehara, Gen

We are currently developing a magnetospinography (MSG) system for noninvasive functional imaging of the spinal cord. The MSG system is a device for observing a weak magnetic field accompanied by the neural activity of the spinal cord by using an array of low-temperature superconducting quantum interference device (SQUID) magnetic flux sensors. As in the case of other biomagnetic measurement systems such as the magnetoencephalography (MEG) system, the running cost of the MSG system is mainly dependent on the liquid helium (LHe) consumption of a dewar vessel. We integrated a cryocooler into the MSG system to reduce LHe consumption. A pulse tube cryocooler with a cooling power of 0.5Wat 4 K was placed adjacent to a magnetically shielded room and was directly connected to the thermal radiation shield of the dewar by an electrically isolated transfer tube. Cold helium gas was circulated between the cryocooler and the radiation shield. Consequently, the temperature of the radiation shield decreased below 40 K. Previous studies have shown that the detection of a weak magnetic field is often hindered by severe low-frequency band noise from the cryocooler. However, the band of the MSG signals is much higher than that of the cryocooler noise. Therefore, the noise can be filtered out and has a less detrimental effect on MSG measurement than on other biomagnetic field measurements such as MEG measurement. As a result, LHe consumption was reduced by 46%, with no increase in the noise floor.

Cryogenic High-Sensitivity Magnetometer

NASA Technical Reports Server (NTRS)

Day, Peter; Chui, Talso; Goodstein, David

2005-01-01

A proposed magnetometer for use in a cryogenic environment would be sensitive enough to measure a magnetic-flux density as small as a picogauss (10(exp -16) Tesla). In contrast, a typical conventional flux-gate magnetometer cannot measure a magnetic-flux density smaller that about 1 microgauss (10(exp -10) Tesla). One version of this device, for operation near the low end of the cryogenic temperature range, would include a piece of a paramagnetic material on a platform, the temperature of which would be controlled with a periodic variation. The variation in temperature would be measured by use of a conventional germanium resistance thermometer. A superconducting coil would be wound around the paramagnetic material and coupled to a superconducting quantum interference device (SQUID) magnetometer.

Large resistance change on magnetic tunnel junction based molecular spintronics devices

NASA Astrophysics Data System (ADS)

Tyagi, Pawan; Friebe, Edward

2018-05-01

Molecular bridges covalently bonded to two ferromagnetic electrodes can transform ferromagnetic materials and produce intriguing spin transport characteristics. This paper discusses the impact of molecule induced strong coupling on the spin transport. To study molecular coupling effect the octametallic molecular cluster (OMC) was bridged between two ferromagnetic electrodes of a magnetic tunnel junction (Ta/Co/NiFe/AlOx/NiFe/Ta) along the exposed side edges. OMCs induced strong inter-ferromagnetic electrode coupling to yield drastic changes in transport properties of the magnetic tunnel junction testbed at the room temperature. These OMCs also transformed the magnetic properties of magnetic tunnel junctions. SQUID and ferromagnetic resonance studies provided insightful data to explain transport studies on the magnetic tunnel junction based molecular spintronics devices.

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.

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

NASA Astrophysics Data System (ADS)

Weinstock, H.

1993-04-01

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

OpenSQUID: A Flexible Open-Source Software Framework for the Control of SQUID Electronics

DOE PAGES

Jaeckel, Felix T.; Lafler, Randy J.; Boyd, S. T. P.

2013-02-06

We report commercially available computer-controlled SQUID electronics are usually delivered with software providing a basic user interface for adjustment of SQUID tuning parameters, such as bias current, flux offset, and feedback loop settings. However, in a research context it would often be useful to be able to modify this code and/or to have full control over all these parameters from researcher-written software. In the case of the STAR Cryoelectronics PCI/PFL family of SQUID control electronics, the supplied software contains modules for automatic tuning and noise characterization, but does not provide an interface for user code. On the other hand, themore » Magnicon SQUIDViewer software package includes a public application programming interface (API), but lacks auto-tuning and noise characterization features. To overcome these and other limitations, we are developing an "open-source" framework for controlling SQUID electronics which should provide maximal interoperability with user software, a unified user interface for electronics from different manufacturers, and a flexible platform for the rapid development of customized SQUID auto-tuning and other advanced features. Finally, we have completed a first implementation for the STAR Cryoelectronics hardware and have made the source code for this ongoing project available to the research community on SourceForge (http://opensquid.sourceforge.net) under the GNU public license.« less

[Biochemistry and functional characterization of squid mantle meat (Dosidicus gigas)].

PubMed

Abugoch, L; Guarda, A; María Pérez, L; Isabel Donghi, M

2000-12-01

A study for the characterization of frozen giant squid mantle (meat) protein stored at -25 degrees C for 8 month was started. In the present research, the following functional properties were investigate: emulsifying, water holding and gel forming capacities. Optimal conditions for the separation and differentiation of miofibrillar and sarcoplasmatic proteins were also studied. It was found that the unfrozen giant squid mantle meat es capable of emulifying 2.817,4 g of oil/g of protein and holding capacity was 3.64 g of water/g of protein. Related to the gel forming capacity, it was not obtain, probably due to excessive storage of the meat. With regard to miofibrilar protein obtention of the squid mantle meat, it was found that two low ionic strength washings (I = 0.05), the sarcoplasmic proteins were practically eliminated from the protein matrix. The differentiation of miofibrilar and sarcoplasmatic proteins was obtained by PAGE-SDS of the squid mantle meat extracted at two different ionic strength (I = 0.05 and I = 0.5). This work demonstrates that the giant squid mantle protein has a high emulsifying and water holding capacity, and it can be used, as a raw material, for the improvement of sausage products. About the gelling products, more studies will be necessary with fresh squid mantle meat to conclude about this functional property.

Structural elements of the signal propagation pathway in squid rhodopsin and bovine rhodopsin.

PubMed

Sugihara, Minoru; Fujibuchi, Wataru; Suwa, Makiko

2011-05-19

Squid and bovine rhodopsins are G-protein coupled receptors (GPCRs) that activate Gq- and Gt-type G-proteins, respectively. To understand the structural elements of the signal propagation pathway, we performed molecular dynamics (MD) simulations of squid and bovine rhodopsins plus a detailed sequence analysis of class A GPCRs. The computations indicate that although the geometry of the retinal is similar in bovine and squid rhodopsins, the important interhelical hydrogen bond networks are different. In squid rhodopsin, an extended hydrogen bond network that spans ∼13 Å to Tyr315 on the cytoplasmic site is present regardless of the protonation state of Asp80. In contrast, the extended hydrogen bond network is interrupted at Tyr306 in bovine rhodopsin. Those differences in the hydrogen bond network may play significant functional roles in the signal propagation from the retinal binding site to the cytoplasmic site, including transmembrane helix (TM) 6 to which the G-protein binds. The MD calculations demonstrate that the elongated conformation of TM6 in squid rhodopsin is stabilized by salt bridges formed with helix (H) 9. Together with the interhelical hydrogen bonds, the salt bridges between TM6 and H9 stabilize the protein conformation of squid rhodopsin and may hinder the occurrence of large conformational changes that are observed upon activation of bovine rhodopsin. © 2011 American Chemical Society

Portable MRI developed at Los Alamos

ScienceCinema

Espy, Michelle

2018-02-14

Scientists at Los Alamos National Laboratory are developing an ultra-low-field Magnetic Resonance Imaging (MRI) system that could be low-power and lightweight enough for forward deployment on the battlefield and to field hospitals in the World's poorest regions. "MRI technology is a powerful medical diagnostic tool," said Michelle Espy, the Battlefield MRI (bMRI) project leader, "ideally suited for imaging soft-tissue injury, particularly to the brain." But hospital-based MRI devices are big and expensive, and require considerable infrastructure, such as large quantities of cryogens like liquid nitrogen and helium, and they typically use a large amount of energy. "Standard MRI machines just can't go everywhere," said Espy. "Soldiers wounded in battle usually have to be flown to a large hospital and people in emerging nations just don't have access to MRI at all. We've been in contact with doctors who routinely work in the Third World and report that MRI would be extremely valuable in treating pediatric encephalopathy, and other serious diseases in children." So the Los Alamos team started thinking about a way to make an MRI device that could be relatively easy to transport, set up, and use in an unconventional setting. Conventional MRI machines use very large magnetic fields that align the protons in water molecules to then create magnetic resonance signals, which are detected by the machine and turned into images. The large magnetic fields create exceptionally detailed images, but they are difficult and expensive to make. Espy and her team wanted to see if images of sufficient quality could be made with ultra-low-magnetic fields, similar in strength to the Earth's magnetic field. To achieve images at such low fields they use exquisitely sensitive detectors called Superconducting Quantum Interference Devices, or SQUIDs. SQUIDs are among the most sensitive magnetic field detectors available, so interference with the signal is the primary stumbling block. "SQUIDs are so sensitive they'll respond to a truck driving by outside or a radio signal 50 miles away," said Al Urbaitis, a bMRI engineer. The team's first generation bMRI had to be built in a large metal housing in order to shield it from interference. Now the Los Alamos team is working in the open environment without the large metal housing using a lightweight series of wire coils that surround the bMRI system to compensate the Earth’s magnetic field. In the future, the field compensation system will also function similar to noise-cancelling headphones to eradicate invading magnetic field signals on-the-fly.

Portable MRI developed at Los Alamos

DOE Office of Scientific and Technical Information (OSTI.GOV)

Espy, Michelle

Scientists at Los Alamos National Laboratory are developing an ultra-low-field Magnetic Resonance Imaging (MRI) system that could be low-power and lightweight enough for forward deployment on the battlefield and to field hospitals in the World's poorest regions. "MRI technology is a powerful medical diagnostic tool," said Michelle Espy, the Battlefield MRI (bMRI) project leader, "ideally suited for imaging soft-tissue injury, particularly to the brain." But hospital-based MRI devices are big and expensive, and require considerable infrastructure, such as large quantities of cryogens like liquid nitrogen and helium, and they typically use a large amount of energy. "Standard MRI machines justmore » can't go everywhere," said Espy. "Soldiers wounded in battle usually have to be flown to a large hospital and people in emerging nations just don't have access to MRI at all. We've been in contact with doctors who routinely work in the Third World and report that MRI would be extremely valuable in treating pediatric encephalopathy, and other serious diseases in children." So the Los Alamos team started thinking about a way to make an MRI device that could be relatively easy to transport, set up, and use in an unconventional setting. Conventional MRI machines use very large magnetic fields that align the protons in water molecules to then create magnetic resonance signals, which are detected by the machine and turned into images. The large magnetic fields create exceptionally detailed images, but they are difficult and expensive to make. Espy and her team wanted to see if images of sufficient quality could be made with ultra-low-magnetic fields, similar in strength to the Earth's magnetic field. To achieve images at such low fields they use exquisitely sensitive detectors called Superconducting Quantum Interference Devices, or SQUIDs. SQUIDs are among the most sensitive magnetic field detectors available, so interference with the signal is the primary stumbling block. "SQUIDs are so sensitive they'll respond to a truck driving by outside or a radio signal 50 miles away," said Al Urbaitis, a bMRI engineer. The team's first generation bMRI had to be built in a large metal housing in order to shield it from interference. Now the Los Alamos team is working in the open environment without the large metal housing using a lightweight series of wire coils that surround the bMRI system to compensate the Earth’s magnetic field. In the future, the field compensation system will also function similar to noise-cancelling headphones to eradicate invading magnetic field signals on-the-fly.« less

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.

75 FR 61639 - Fisheries of the Exclusive Economic Zone Off Alaska; Skate Management in the Groundfish Fisheries...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-06

... and GOA sharks, sculpins, and octopuses, and GOA squids as a group for purposes of prohibited species.../npfmc/default.htm . One alternative previously adopted for a Tier 6 stock (squid and octopus in the GOA... groups (sharks, skates, sculpins, octopus, or squid) approaches overfishing. Response: See the response...

77 FR 74159 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-13

.... SUMMARY: NMFS proposes changing the butterfish mortality cap on the longfin squid fishery from a catch cap to a discard cap in Framework Adjustment 7 to the Atlantic Mackerel, Squid, and Butterfish Fishery Management Plan,. This action also proposes reducing the butterfish mortality cap for the 2013 fishing year...

Is there a relationship between curvature and inductance in the Josephson junction?

NASA Astrophysics Data System (ADS)

Dobrowolski, T.; Jarmoliński, A.

2018-03-01

A Josephson junction is a device made of two superconducting electrodes separated by a very thin layer of isolator or normal metal. This relatively simple device has found a variety of technical applications in the form of Superconducting Quantum Interference Devices (SQUIDs) and Single Electron Transistors (SETs). One can expect that in the near future the Josephson junction will find applications in digital electronics technology RSFQ (Rapid Single Flux Quantum) and in the more distant future in construction of quantum computers. Here we concentrate on the relation of the curvature of the Josephson junction with its inductance. We apply a simple Capacitively Shunted Junction (CSJ) model in order to find condition which guarantees consistency of this model with prediction based on the Maxwell and London equations with Landau-Ginzburg current of Cooper pairs. This condition can find direct experimental verification.

US Navy superconductivity program

NASA Technical Reports Server (NTRS)

Gubser, Donald U.

1991-01-01

Both the new high temperature superconductors (HTS) and the low temperature superconductors (LTS) are important components of the Navy's total plan to integrate superconductivity into field operational systems. Fundamental research is an important component of the total Navy program and focuses on the HTS materials. Power applications (ship propulsion) use LTS materials while space applications (millimeter wave electronics) use HTS materials. The Space Experiment to be conducted at NRL will involve space flight testing of HTS devices built by industry and will demonstrate the ability to engineer and space qualify these devices for systems use. Another important component of the Navy's effort is the development of Superconducting Quantum Interference Device (SQUID) magnetometers. This program will use LTS materials initially, but plans to implement HTS materials as soon as possible. Hybrid HTS/LTS systems are probable in many applications. A review of the status of the Navy's HTS materials research is given as well as an update on the Navy's development efforts in superconductivity.

Effect of single- and two-cycle high hydrostatic pressure treatments on water properties, physicochemical and microbial qualities of minimally processed squids (todarodes pacificus).

PubMed

Zhang, Yifeng; Jiao, Shunshan; Lian, Zixuan; Deng, Yun; Zhao, Yanyun

2015-05-01

This study investigated the effect of single- and two-cycle high hydrostatic pressure (HHP) treatments on water properties, physicochemical, and microbial qualities of squids (Todarodes pacificus) during 4 °C storage for up to 10 d. Single-cycle treatments were applied at 200, 400, or 600 MPa for 20 min (S-200, S-400, and S-600), and two-cycle treatments consisted of two 10 min cycles at 200, 400, or 600 MPa, respectively (T-200, T-400, and T-600). HHP-treated samples had higher (P < 0.05) content of P2b (immobilized water) and P21 (myofibril water), but lower P22 (free water) than those of control. The single- and two-cycle HHP treatments at the same pressure level caused no significant difference in water state of squids. The two-cycle HHP treatment was more effective in controlling total volatile basic nitrogen, pH, and total plate counts (TPC) of squids during storage, in which TPC of S-600 and T-600 was 2.9 and 1.8 log CFU/g at 10 d, respectively, compared with 7.5 log CFU/g in control. HHP treatments delayed browning discoloration of the squids during storage, and the higher pressure level and two-cycle HHP were more effective. Water properties highly corresponded with color and texture indices of squids. This study demonstrated that the two-cycle HHP treatment was more effective in controlling microbial growth and quality deterioration while having similar impact on the physicochemical and water properties of squids in comparison with the single-cycle treatment, thus more desirable for extending shelf-life of fresh squids. © 2015 Institute of Food Technologists®

A shot in the dark: same-sex sexual behaviour in a deep-sea squid.

PubMed

Hoving, Hendrik J T; Bush, Stephanie L; Robison, Bruce H

2012-04-23

Little is known about the reproductive habits of deep-living squids. Using remotely operated vehicles in the deep waters of the Monterey Submarine Canyon, we have found evidence of mating, i.e. implanted sperm packages, on similar body locations in males and females of the rarely seen mesopelagic squid Octopoteuthis deletron. Equivalent numbers of both sexes were found to have mated, indicating that male squid routinely and indiscriminately mate with both males and females. Most squid species are short-lived, semelparous (i.e. with a single, brief reproductive period) and promiscuous. In the deep, dark habitat where O. deletron lives, potential mates are few and far between. We suggest that same-sex mating behaviour by O. deletron is part of a reproductive strategy that maximizes success by inducing males to indiscriminately and swiftly inseminate every conspecific that they encounter.

77 FR 16472 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-21

...NMFS is implementing final 2012 specifications and management measures for Atlantic mackerel (mackerel), and 2012-2014 specifications for Illex and longfin squid, and interim final 2012 specifications and management measures for butterfish. This is the first year that the specifications are being set for Atlantic mackerel and butterfish under the provisions of the Mid-Atlantic Fishery Management Council's (Council) Annual Catch Limit and Accountability Measure Omnibus Amendment. This action also adjusts the closure threshold for the commercial mackerel fishery to 95 percent (from 90 percent), and allows the use of jigging gear to target longfin squid if the longfin squid fishery is closed due to the butterfish mortality cap. Finally, this rule makes minor corrections in existing regulatory text to clarify the intent of the regulations. These specifications and management measures promote the utilization and conservation of the Atlantic Mackerel, Squid, and Butterfish (MSB) resource.

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.

Feasibility Study of the Superconducting Gravity Gradiometer (SGG) Flight Test on the European Retrievable Carrier (EURECA)

NASA Technical Reports Server (NTRS)

1991-01-01

A study was performed to determine the feasibility of conducting a flight test of the Superconducting Gravity Gradiometer (SGG) Experiment Module on one of the reflights of the European Retrievable Carrier (EURECA). EURECA was developed expressly to accommodate space science experimentation, while providing a high quality microgravity environment. As a retrievable carrier, it offers the ability to recover science experiments after a nominal six months of operations in orbit. The study concluded that the SGG Experiment Module can be accommodated and operated in a EURECA reflight mission. It was determined that such a flight test would enable the verification of the SGG Instrument flight performance and validate the design and operation of the Experiment Module. It was also concluded that a limited amount of scientific data could be obtained on this mission.

Reducing tensor magnetic gradiometer data for unexploded ordnance detection

USGS Publications Warehouse

Bracken, Robert E.; Brown, Philip J.

2005-01-01

We performed a survey to demonstrate the effectiveness of a prototype tensor magnetic gradiometer system (TMGS) for detection of buried unexploded ordnance (UXO). In order to achieve a useful result, we designed a data-reduction procedure that resulted in a realistic magnetic gradient tensor and devised a simple way of viewing complicated tensor data, not only to assess the validity of the final resulting tensor, but also to preview the data at interim stages of processing. The final processed map of the surveyed area clearly shows a sharp anomaly that peaks almost directly over the target UXO. This map agrees well with a modeled map derived from dipolar sources near the known target locations. From this agreement, it can be deduced that the reduction process is valid, making the prototype TMGS a foundation for development of future systems and processes.

Tuning the Stiffness Balance Using Characteristic Frequencies as a Criterion for a Superconducting Gravity Gradiometer

PubMed Central

Liu, Xikai; Ma, Dong; Chen, Liang; Liu, Xiangdong

2018-01-01

Tuning the stiffness balance is crucial to full-band common-mode rejection for a superconducting gravity gradiometer (SGG). A reliable method to do so has been proposed and experimentally tested. In the tuning scheme, the frequency response functions of the displacement of individual test mass upon common-mode accelerations were measured and thus determined a characteristic frequency for each test mass. A reduced difference in characteristic frequencies between the two test masses was utilized as the criterion for an effective tuning. Since the measurement of the characteristic frequencies does not depend on the scale factors of displacement detection, stiffness tuning can be done independently. We have tested this new method on a single-component SGG and obtained a reduction of two orders of magnitude in stiffness mismatch. PMID:29419796

A superconducting gravity gradiometer for measurements from a moving vehicle.

PubMed

Moody, M V

2011-09-01

A gravity gradiometer designed for operation on an aircraft or ship has been tested in the laboratory. A noise level of 0.53 E (E ≡ 10(-9) s(-2)) rms over a 0.001 to 1 Hz bandwidth has been measured, and the primary error mechanisms have been analyzed and quantified. The design is a continuation in the development of superconducting accelerometer technology at the University of Maryland over more than three decades. A cryogenic instrument presents not only the benefit of reduced thermal noise, but also, the extraordinary stability of superconducting circuits and material properties at very low temperatures. This stability allows precise matching of scale factors and accurate rejection of dynamic errors. The design of the instrument incorporates a number of additional features that further enhance performance in a dynamically noisy environment. © 2011 American Institute of Physics

Archaeogeophysical Surveys on Mersin, Silifke, Uzuncaburç (Diokaisareia) Zeus Olbios Temple

NASA Astrophysics Data System (ADS)

Ahmet Yüksel, Fethi; Deniz, Hazel; Şahin, Hamdi

2017-04-01

The ancient city of Diocaesarea (Uzuncaburç), located 30 km north Silifke in Mersin, was a temple centre subjected to Olba in the Hellenistic period. It was declared as free city by Tiberius in the Early Imperial period and it flourished until the 5th century AD. During this period, a Thykhaion to the west of the city was built in the 1st century AD by Obrimos and his son Oppius from his wife Kyria, daughter of Leonidas. A theater was also erected in the co-reign of Marcus Aurelius and Lucius Verus and the city gate in the west of Diocaesarea was repaired under Arcadius and Honorius (396-408 AD). It was financed by the dux ad comes of Isauria, Leontios. In July 2011, archaeogeophysical measurements were made on the columns of the town of Zeus Olbios and on the peripteral Street of the city by magnetic methods. The purpose of these investigations is to determine the presence of architectural remains under the ground at the points specified. G-858 Cesium Gradiometer (G-858 Cesium Gradiometer) was used for magnetic measurement. These measurements were made on 38 pitches of 20 m length in Zeus Olbios temple on 13 creeks of 160 m length on the city's columned street. obtained sub-sensor, top sensor and gradient magnetic maps are created. Linear, angular locations with high susceptibilty were identified on magnetic maps. Keywords: Magnetic, Diokaisareia (Uzuncahurç), Archaeogeophysics, Archaeology, Cesium Gradiometer

A SQUID-Based RF Cavity Search for Dark Matter Axions

NASA Astrophysics Data System (ADS)

Hotz, Michael T.

The axion is a hypothetical elementary particle resulting from a solution to the "Strong-CP" problem. This serious problem in the standard model of particle physics is manifested as a 1010 discrepancy between the measured upper limit and the calculated value of the neutron's electric dipole moment. Furthermore, a light (~mueV) axion is an ideal dark matter candidate: axions would have been copiously produced during the Big Bang and would be the primary component of the dark matter in the universe. The resolution of the Strong-CP problem and the discovery of the composition of dark matter are two of the most pressing problems in physics. The observation of a light, dark-matter axion would resolve both of these problems. The Axion Dark Matter eXperiment (ADMX) is the most sensitive search for dark-matter axions. Axions in our Milky Way Galaxy may scatter off a magnetic field and convert into microwave photons. ADMX consists of a tunable high-Q RF cavity within the bore of a large, 8.5 Tesla superconducting solenoidal magnet. When the cavity's resonant frequency matches the axion's total energy, the probability of axion-to-photon conversion is enhanced. The cavity's narrow bandwidth requires ADMX to slowly scan possible axion masses. A receiver amplifies, mixes, and digitizes the power developed in the cavity from possible axion-to-photon conversions. This is the most sensitive spectral receiver of microwave radiation in the world. The resulting data is scrutinized for an axion signal above the thermal background. ADMX first operated from 1995-2005 and produced exclusion limits on the energy of dark-matter axions from 1.9 mueV to 3.3 mueV. In order to improve on these limits and continue the search for plausible dark-matter axions, the system was considerably upgraded from 2005 until 2008. In the upgrade, the key technical advance was the use of a dc Superconducting QUantum Interference Device (SQUID) as a microwave amplifier. The SQUID amplifier's noise level is near the allowed minimum from quantum mechanics, allowing ADMX to reduce its thermal noise background by up to 100x. However, SQUIDs are extremely sensitive to magnetic fields, such as those within in ADMX. Integrating a SQUID amplifier into ADMX presented a serious technical challenge. Commissioning the SQUID amplifier was a major focus of my thesis work. This work demonstrates the successful use of a SQUID amplifier in ADMX during operations from 2008-2010. Compared to other dark-matter candidates, the axion's mass and the axion's coupling strength to normal matter and radiation are rather tightly constrained. This allows for the near-definitive elimination or detection of dark-matter axions. A successful detection in ADMX would immediately lead to a determination of the axion's spectral line shape. This shape encodes the history of the Milky Way's formation and is therefore of high scientific importance. The imperfectly-constrained Milky Way dark-matter halo, however, produces remnant uncertainties of the axion signal in both its spectral line-shape and its total intensity, complicating the ADMX search. This work investigates proposed features of dark-matter halo models which enhance ADMX's sensitivity. From these models, this work presents the corresponding exclusion limits for both the local axion density and axion-to-photon coupling strength for axions with mass in the 3.36 mueV to 3.69 mueV region.

Fabrication and Performance of Large Format Transition Edge Sensor Microcalorimeter Arrays

NASA Technical Reports Server (NTRS)

Chervenak, James A.; Adams, James S.; Bandler, Simon R.; Busch, Sara E.; Eckart, M. E.; Ewin, A. E.; Finkbeiner, F. M.; Kilbourne, C. A.; Kelley, R. L.; Porst, Jan-Patrick;

76 FR 3044 - Fisheries of the Exclusive Economic Zone Off Alaska; Sculpins, Sharks, Squid, and Octopus in the...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-19

..., Squid, and Octopus in the Gulf of Alaska AGENCY: National Marine Fisheries Service (NMFS), National... prohibiting directed fishing for sculpins, sharks, squid, and octopus in the Gulf of Alaska (GOA). This action..., and octopus in the GOA. DATES: Effective 1200 hrs, Alaska local time (A.l.t.), January 13, 2011...

Macroscale and Microscale Structural Characterization of Cephalopod Chromatophores

DTIC Science & Technology

2011-04-01

ABSTRACT Cephalopods, the class of mollusks that include squid, cuttlefish, and octopus , possess skin with dynamic adaptable appearance. Their unique...Cephalopods, the class of mollusks that include squid, cuttlefish, and octopus , possess skin with dynamic adaptable appearance. Their unique ability to...Cephalopoda including cuttlefish, octopus , and squid (Hanlon, 2007; Hanlon and Messenger, 1996; Hanlon, 1982; Hanlon and Messenger, 1988). These

Designing a Microhydraulically driven Mini robotic Squid

DTIC Science & Technology

2016-05-20

applications for microrobots include remote monitoring, surveillance, search and rescue, nanoassembly, medicine, and in-vivo surgery . Robotics platforms...Secretary of Defense for Research and Engineering. Designing a Microhydraulically-driven Mini- robotic Squid by Kevin Dehan Meng B.S., U.S. Air...Committee on Graduate Students 2 Designing a Microhydraulically-driven Mini- robotic Squid by Kevin Dehan Meng Submitted to the Department

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

PubMed

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

2008-06-15

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

[A study on feeding ecology and migration patterns of Dosidicus gigas off Peru using stable isotope analysis].

PubMed

Gong, Yi; Chen, Xin-jun; Li, Yun-kai; Han, Meng-jie

2015-09-01

As a pelagic cephalopod and one of the main target species of Chinese distant water fishery, jumbo squids (Dosidicus gigas) play a major role in the marine ecosystems of the eastern Pacific. Understanding the feeding ecology and migration patterns of jumbo squids is of importance for better utilizing the resources. The isotopic signatures of gladius, have been proved to be a powerful tool to reveal high resolution and ontogenic variations in individual foraging strategies of squids; which is an archival tissue with no elemental turnover after formation. In this study, the growth equation of gladius proostracum was established based on the age information determined by statolith. Gladius was cut successionally by the growth curve of gladius proostracum, the stable isotopic values of the gladius profiles were determined, and the feeding ecology and migration patterns of jumbo squids during its growth process were investigated. Results showed that the jumbo squids began to migrate after 180 days of postnatal, and their trophic levels tended to decrease throughout the life span. These results demonstrated the feasibility of using continuous sampling hard tissue to study the feeding ecology and habitat transfer of jumbo squids.

ESR studies on the thermal decomposition of trimethylamine oxide to formaldehyde and dimethylamine in jumbo squid (Dosidicus gigas) extract.

PubMed

Zhu, Junli; Jia, Jia; Li, Xuepeng; Dong, Liangliang; Li, Jianrong

2013-12-15

The effects of ferrous iron, heating temperature and different additives on the decomposition of trimethylamine oxide (TMAO) to formaldehyde (FA) and dimethylamine (DMA) and generation of free radicals in jumbo squid (Dosidicus gigas) extract during heating were evaluated by electron spin resonance (ESR). The thermal decomposition of TMAO to TMA, DMA and FA and free radical signals was observed in squid extract, whereas no DMA, FA and free radical signals were detected in cod extract or in aqueous TMAO solution in vitro at high temperatures. Significant increase in levels of DMA, FA and radicals intensity were observed in squid extract and TMAO solution in the presence of ferrous iron with increasing temperature. Hydrogen peroxide stimulated the production of DMA, FA and ESR signals in squid extract, while citric acid, trisodium citrate, calcium chloride, tea polyphenols and resveratrol had the opposite effect. Similar ESR spectra of six peaks regarded as amminium radical were detected in the squid extract and TMAO-iron(II) solution, suggesting that the amminium radical was involved in the decomposition of TMAO. Copyright © 2013 Elsevier Ltd. All rights reserved.

Deep-sea in situ observations of gonatid squid and their prey reveal high occurrence of cannibalism

NASA Astrophysics Data System (ADS)

Hoving, H. J. T.; Robison, B. H.

2016-10-01

In situ observations are rarely applied in food web studies of deep-sea organisms. Using deep-sea observations obtained by remotely operated vehicles in the Monterey Submarine Canyon, we examined the prey choices of more than 100 individual squids of the genus Gonatus. Off the California coast, these squids are abundant, semelparous (one reproductive cycle) oceanic predators but their diet has remained virtually unknown. Gonatus onyx and Gonatus berryi were observed to feed on mesopelagic fishes (in particular the myctophid Stenobrachius leucopsarus) as often as on squids but inter-specific differences in feeding were apparent. Gonatids were the most common squid prey and while cannibalism occurred in both species it was particularly high in Gonatus onyx (42% of all prey items). Typically, the size of prey was similar to the size of the predator but the squids were also seen to take much larger prey. Postjuvenile gonatids are opportunistic predators that consume nektonic members of the meso-and bathypelagic communities, including their own species. Such voracious feeding is likely necessary to support the high energetic demands associated with the single reproductive event; and for females the long brooding period during which they must depend on stored resources.

The giant eyes of giant squid are indeed unexpectedly large, but not if used for spotting sperm whales.

PubMed

Nilsson, Dan-E; Warrant, Eric J; Johnsen, Sönke; Hanlon, Roger T; Shashar, Nadav

2013-09-08

We recently reported (Curr Biol 22:683-688, 2012) that the eyes of giant and colossal squid can grow to three times the diameter of the eyes of any other animal, including large fishes and whales. As an explanation to this extreme absolute eye size, we developed a theory for visual performance in aquatic habitats, leading to the conclusion that the huge eyes of giant and colossal squid are uniquely suited for detection of sperm whales, which are important squid-predators in the depths where these squid live. A paper in this journal by Schmitz et al. (BMC Evol Biol 13:45, 2013) refutes our conclusions on the basis of two claims: (1) using allometric data they argue that the eyes of giant and colossal squid are not unexpectedly large for the size of the squid, and (2) a revision of the values used for modelling indicates that large eyes are not better for detection of approaching sperm whales than they are for any other task. We agree with Schmitz et al. that their revised values for intensity and abundance of planktonic bioluminescence may be more realistic, or at least more appropriately conservative, but argue that their conclusions are incorrect because they have not considered some of the main arguments put forward in our paper. We also present new modelling to demonstrate that our conclusions remain robust, even with the revised input values suggested by Schmitz et al.

75 FR 1024 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-08

... rulemaking (ANPR); notice to reaffirm the control date for the Loligo squid (Loligo) and Illex squid (Illex...: Public comments on the ANPR must be received no later than 5 p.m., eastern standard time, on February 8... fisheries since 2003. On May 20, 2003 (68 FR 27516), NMFS published, at the request of the Council, an ANPR...

The GOCE end-to-end system simulator

NASA Astrophysics Data System (ADS)

Catastini, G.; Cesare, S.; de Sanctis, S.; Detoma, E.; Dumontel, M.; Floberghagen, R.; Parisch, M.; Sechi, G.; Anselmi, A.

2003-04-01

The idea of an end-to-end simulator was conceived in the early stages of the GOCE programme, as an essential tool for assessing the satellite system performance, that cannot be fully tested on the ground. The simulator in its present form is under development at Alenia Spazio for ESA since the beginning of Phase B and is being used for checking the consistency of the spacecraft and of the payload specifications with the overall system requirements, supporting trade-off, sensitivity and worst-case analyses, and preparing and testing the on-ground and in-flight calibration concepts. The software simulates the GOCE flight along an orbit resulting from the application of Earth's gravity field, non-conservative environmental disturbances (atmospheric drag, coupling with Earth's magnetic field, etc.) and control forces/torques. The drag free control forces as well as the attitude control torques are generated by the current design of the dedicated algorithms. Realistic sensor models (star tracker, GPS receiver and gravity gradiometer) feed the control algorithms and the commanded forces are applied through realistic thruster models. The output of this stage of the simulator is a time series of Level-0 data, namely the gradiometer raw measurements and spacecraft ancillary data. The next stage of the simulator transforms Level-0 data into Level-1b (gravity gradient tensor) data, by implementing the following steps: - transformation of raw measurements of each pair of accelerometers into common and differential accelerations - calibration of the common and differential accelerations - application of the post-facto algorithm to rectify the phase of the accelerations and to estimate the GOCE angular velocity and attitude - computation of the Level-1b gravity gradient tensor from calibrated accelerations and estimated angular velocity in different reference frames (orbital, inertial, earth-fixed); computation of the spectral density of the error of the tensor diagonal components (measured gravity gradient minus input gravity gradient) in order to verify the requirement on the error of gravity gradient of 4 mE/sqrt(Hz) within the gradiometer measurement bandwidth (5 to 100 mHz); computation of the spectral density of the tensor trace in order to verify the requirement of 4 sqrt(3) mE/sqrt(Hz) within the measurement bandwidth - processing of GPS observations for orbit reconstruction within the required 10m accuracy and for gradiometer measurement geolocation. The current version of the end-to-end simulator, essentially focusing on the gradiometer payload, is undergoing detailed testing based on a time span of 10 days of simulated flight. This testing phase, ending in January 2003, will verify the current implementation and conclude the assessment of numerical stability and precision. Following that, the exercise will be repeated on a longer-duration simulated flight and the lesson learnt so far will be exploited to further improve the simulator's fidelity. The paper will describe the simulator's current status and will illustrate its capabilities for supporting the assessment of the quality of the scientific products resulting from the current spacecraft and payload design.

A Spread-Spectrum SQUID Multiplexer

NASA Astrophysics Data System (ADS)

Irwin, K. D.; Chaudhuri, S.; Cho, H.-M.; Dawson, C.; Kuenstner, S.; Li, D.; Titus, C. J.; Young, B. A.

2018-06-01

The transition-edge sensor (TES) is a mature, high-resolution x-ray spectrometer technology that provides a much higher efficiency than dispersive spectrometers such as gratings and crystal spectrometers. As larger arrays are developed, time-division multiplexing schemes operating at MHz frequencies are being replaced by microwave SQUID multiplexers using frequency-division multiplexing at GHz frequencies. However, the multiplexing factor achievable with microwave SQUIDs is limited by the high slew rate on the leading edge of x-ray pulses. In this paper, we propose a new multiplexing scheme for high-slew-rate TES x-ray calorimeters: the spread-spectrum SQUID multiplexer, which has the potential to enable higher multiplexing factors, especially in applications with lower photon-arrival rates.

Routine clinical heart examinations using SQUID magnetocardiography at University of Tsukuba Hospital

NASA Astrophysics Data System (ADS)

Inaba, T.; Nakazawa, Y.; Yoshida, K.; Kato, Y.; Hattori, A.; Kimura, T.; Hoshi, T.; Ishizu, T.; Seo, Y.; Sato, A.; Sekiguchi, Y.; Nogami, A.; Watanabe, S.; Horigome, H.; Kawakami, Y.; Aonuma, K.

2017-11-01

A 64-channel Nb-based DC-SQUID magnetocardiography (MCG) system was installed at the University of Tsukuba Hospital (UTH) in March 2007 after obtaining Japanese pharmaceutical approval and insurance reimbursement approval. In the period between 2008 and 2016, the total number of patients was 10 085. The heart diseases diagnosed in fetuses as well as adults are mainly atrial arrhythmia, abnormal repolarization, ventricular arrhythmia, and fetal arrhythmia. In most cases of insufficient diagnostic accuracy with electrocardiography, SQUID MCG precisely revealed these heart diseases as an abnormal electrical current distribution. Based on success in routine examinations, SQUID MCG is now an indispensable clinical instrument with diagnostic software tuned up during routine use at UTH.

Sub-millimeter scale magnetostratigraphy and environmental magnetism of ferromanganese crusts using a scanning SQUID microscope

NASA Astrophysics Data System (ADS)

Oda, H.; Noguchi, A.; Yamamoto, Y.; Usui, A.; Ito, T.; Kawai, J.; Takahashi, H.

2017-12-01

Ferromanganese crusts are chemical sedimentary rock composed mainly of iron-manganese oxide. Because the ferromanganese crusts grow very slowly on the sea floor at rates of 3-10 mm/Ma, long-term deep-sea environmental changes can be reconstructed from the ferromanganese crusts. Thus, it is important to provide reliable age model for the crusts. For the past decades 10Be/9Be dating method has been used extensively to give age models for crusts younger than 15 Ma. Alternatively, sub-millimeter scale magnetostratigraphic study on a ferromanganese crust sample using a scanning SQUID (superconducting quantum interference device) microscope (Kawai et al., 2016; Oda et al., 2016) has been applied successfully (e.g. Oda et al., 2011; Noguchi et al. 2017). Also, environmental magnetic mapping was successful for the ferromanganese crust from the Takuyo Daigo Seamount (Noguchi et al., 2017). The ferromanganese crust used in this study was sampled from the Hanzawa Seamount, Ryukyu trench and the Shotoku Seamount. The vertical component of the magnetic field above thin section samples of the ferromanganese crust was measured using the scanning SQUID microscope on 100 μm grids. Magnetic mapping of the Hanzawa Seamount shows sub-millimeter scale magnetic stripes parallel to lamina. By correlating the boundaries of magnetic stripes with known geomagnetic reversals, we estimated that average growth rate of the Hanzawa Seamount is 2.67 +/- 0.04 mm/Ma , which is consistent with that deduced from the 10Be/9Be dating method (2.56 +/- 0.04 mm/Ma). The crust sample from the Shotoku Seamount used by Oda et al. (2011) shows prominent periodical lamination. Further details are going to be discussed together with the environmental magnetic mapping.

Large resistance change on magnetic tunnel junction based molecular spintronics devices

DOE PAGES

Tyagi, Pawan; Friebe, Edward

2018-01-12

Here, molecular bridges covalently bonded to two ferromagnetic electrodes can transform ferromagnetic materials and produce intriguing spin transport characteristics. This paper discusses the impact of molecule induced strong coupling on the spin transport. To study molecular coupling effect the octametallic molecular cluster (OMC) was bridged between two ferromagnetic electrodes of a magnetic tunnel junction (Ta/Co/NiFe/AlOx/NiFe/Ta) along the exposed side edges. OMCs induced strong inter-ferromagnetic electrode coupling to yield drastic changes in transport properties of the magnetic tunnel junction testbed at the room temperature. These OMCs also transformed the magnetic properties of magnetic tunnel junctions. SQUID and ferromagnetic resonance studies providedmore » insightful data to explain transport studies on the magnetic tunnel junction based molecular spintronics devices.« less

Large resistance change on magnetic tunnel junction based molecular spintronics devices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tyagi, Pawan; Friebe, Edward

Here, molecular bridges covalently bonded to two ferromagnetic electrodes can transform ferromagnetic materials and produce intriguing spin transport characteristics. This paper discusses the impact of molecule induced strong coupling on the spin transport. To study molecular coupling effect the octametallic molecular cluster (OMC) was bridged between two ferromagnetic electrodes of a magnetic tunnel junction (Ta/Co/NiFe/AlOx/NiFe/Ta) along the exposed side edges. OMCs induced strong inter-ferromagnetic electrode coupling to yield drastic changes in transport properties of the magnetic tunnel junction testbed at the room temperature. These OMCs also transformed the magnetic properties of magnetic tunnel junctions. SQUID and ferromagnetic resonance studies providedmore » insightful data to explain transport studies on the magnetic tunnel junction based molecular spintronics devices.« less

Combined climate- and prey-mediated range expansion of Humboldt squid (Dosidicus gigas), a large marine predator in the California Current System.

PubMed

Stewart, Julia S; Hazen, Elliott L; Bograd, Steven J; Byrnes, Jarrett E K; Foley, David G; Gilly, William F; Robison, Bruce H; Field, John C

2014-06-01

Climate-driven range shifts are ongoing in pelagic marine environments, and ecosystems must respond to combined effects of altered species distributions and environmental drivers. Hypoxic oxygen minimum zones (OMZs) in midwater environments are shoaling globally; this can affect distributions of species both geographically and vertically along with predator-prey dynamics. Humboldt (jumbo) squid (Dosidicus gigas) are highly migratory predators adapted to hypoxic conditions that may be deleterious to their competitors and predators. Consequently, OMZ shoaling may preferentially facilitate foraging opportunities for Humboldt squid. With two separate modeling approaches using unique, long-term data based on in situ observations of predator, prey, and environmental variables, our analyses suggest that Humboldt squid are indirectly affected by OMZ shoaling through effects on a primary food source, myctophid fishes. Our results suggest that this indirect linkage between hypoxia and foraging is an important driver of the ongoing range expansion of Humboldt squid in the northeastern Pacific Ocean. © 2014 John Wiley & Sons Ltd.

Superconducting gravity gradiometer mission. Volume 1: Study team executive summary

NASA Technical Reports Server (NTRS)

Morgan, Samuel H. (Editor); Paik, Ho Jung (Editor)

1989-01-01

An executive summary is presented based upon the scientific and engineering studies and developments performed or directed by a Study Team composed of various Federal and University activities involved with the development of a three-axis Superconducting Gravity Gradiometer integrated with a six-axis superconducting accelerometer. This instrument is being developed for a future orbital mission to make precise global gravity measurements. The scientific justification and requirements for such a mission are discussed. This includes geophysics, the primary mission objective, as well as secondary objectives, such as navigation and tests of fundamental laws of physics, i.e., a null test of the inverse square law of gravitation and tests of general relativity. The instrument design and status along with mission analysis, engineering assessments, and preliminary spacecraft concepts are discussed. In addition, critical spacecraft systems and required technology advancements are examined. The mission requirements and an engineering assessment of a precursor flight test of the instrument are discussed.

Superconducting gravity gradiometer mission. Volume 2: Study team technical report

NASA Technical Reports Server (NTRS)

Morgan, Samuel H. (Editor); Paik, Ho Jung (Editor)

1988-01-01

Scientific and engineering studies and developments performed or directed by a Study Team composed of various Federal and University activities involved with the development of a three-axis superconducting gravity gradiometer integrated with a six-axis superconducting accelerometer are examined. This instrument is being developed for a future orbital mission to make precise global gravity measurements. The scientific justification and requirements for such a mission are discussed. This includes geophysics, the primary mission objective, as well as secondary objective, such as navigation and feats of fundamental laws of physics, i.e., a null test of the inverse square law of gravitation and tests of general relativity. The instrument design and status along with mission analysis, engineering assessments, and preliminary spacecraft concepts are discussed. In addition, critical spacecraft systems and required technology advancements are examined. The mission requirements and an engineering assessment of a precursor flight test of the instrument are discussed.

The IfE Global Gravity Field Model Recovered from GOCE Orbit and Gradiometer Data

NASA Astrophysics Data System (ADS)

Wu, Hu; Muiller, Jurgen; Brieden, Phillip

2015-03-01

An independent global gravity field model is computed from the GOCE orbit and gradiometer data using our own IfE software. We analysed the same data period that were considered for the first released GOCE models. The Acceleration Approach is applied to process the orbit data. The gravity gradients are processed in the framework of the remove-restore technique by which the low-frequency noise of the original gradients are removed. For the combined solution, the normal equations are summed by the Variance Component Estimation Approach. The result in terms of accumulated geoid height error calculated from the coefficient difference w.r.t. EGM2008 is about 11 cm at D/O 200, which corresponds to the accuracy level of the first released TIM and DIR solutions. This indicates that our IfE model has a comparable performance as the other official GOCE models.

ELECTROPHORETIC AND IMMUNOLOGICAL STUDIES OF SQUID AXOPLASM PROTEINS.

PubMed

HUNEEUS-COX, F

1964-03-06

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.

Squid - a simple bioinformatics grid.

PubMed

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

2005-08-03

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. 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. 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.

A new spinner magnetometer using high sensitivity magneto-impedance sensor

NASA Astrophysics Data System (ADS)

Kodama, Kazuto

2016-04-01

A sensitive spinner magnetometer was developed using a pair of high-resolution Magneto-Impedance sensors. The MI sensor generally utilizes the MI effect of amorphous wire whose impedance changes by the application of a small magnetic field. Various kinds of MI sensors are currently used in many electric devices, for example, a magnetic compass chip built-in smart phones and car navigations. The MI sensor employed in this study is a pico-Tesla MI sensor, an especially sensitive MI sensor originally manufactured for industrial use to detect contamination of small magnetic particles in industrial materials such as fabrics. To detect weak magnetic signals from natural samples and avoid DC drift, a gradiometer system was employed that consists of a pair of the MI sensors and the electronics with analog filter and pre-amplification circuit. This MI gradiometer system was equipped to a commercial spinner magnetometer (SMD-88, Natsuhara Giken, Osaka) with the spinning rate of 5 Hz. It is demonstrated that this new spinner magnetometer is capable of measuring weak magnetic samples of 10-6 mAm2, with the highest resolution being 10-8 mAm2, approximately two orders of magnitude better than the previous one using a ring-core flux-gate sensor. One of the advantages of the MI spinner magnetometer is that it can be easily modified to accommodate samples of any shape and size. Moreover the slow-rotating speed (5 Hz) allows to measure samples for archeomagnetic studies that are usually irregular and fragile. Because the irregularity of shape increases errors in measuring the dipole component of the total magnetization, it is necessary to increase the distance between the sample and sensor, resulting in poorer sensitivity. The high-sensitivity MI sensor enables to measure the NRM of such irregular-shaped samples from an appropriate distance to the sample, with no significant loss of sensitivity.

Horizontal movements, vertical-habitat utilization and diet of the jumbo squid ( Dosidicus gigas) in the Pacific Ocean off Baja California Sur, Mexico

NASA Astrophysics Data System (ADS)

Bazzino, Gastón; Gilly, William F.; Markaida, Unai; Salinas-Zavala, César A.; Ramos-Castillejos, Jorge

2010-07-01

We deployed four pop-up archival-transmitting (PAT) tags on jumbo squid ( Dosidicus gigas) collected in the Pacific Ocean off the main entrance to Magdalena Bay on the Baja California peninsula in June 2005. This is the first successful deployment of PAT tags on jumbo squid in an area outside the Gulf of California. Summary data were obtained through the ARGOS satellite system for three of the tags; the fourth tag was physically recovered. All of the tagged squid tended to remain on the shallow continental shelf for several days after tagging and then moved offshore into deeper water. Three of the four squid appeared to migrate in a general southerly direction while the fourth remained offshore of Magdalena Bay. All of the squid spent most daylight hours at depths that were associated with the hypoxic oxygen minimum layer, and at night they spent a majority of time in the upper 50 m of the water column. Stomach content analysis and tag temperature-depth data during the first days after tagging revealed that the squid were feeding on pelagic red crabs ( Pleuroncodes planipes) and several larger, neritic fishes over the continental shelf off Magdalena Bay during a seasonal nearshore upwelling. Comparison of our results with those previously collected in the Gulf of California reveal that Dosidicus gigas can vary its behavior and diet to suit local environmental conditions. This adaptability is likely to be an important factor in the ability of D. gigas to invade and colonize new areas.

Tunable microstrip SQUID amplifiers for the Gen 2 Axion Dark Matter eXperiment (ADMX)

NASA Astrophysics Data System (ADS)

O'Kelley, Sean; Hilton, Gene; Clarke, John; ADMX Collaboration

2016-03-01

We present a series of tunable microstrip SQUID (Superconducting Quantum Interference Device) amplifiers (MSAs) for installation in ADMX. The axion dark matter candidate is detected via Primakoff conversion to a microwave photon in a high-Q (~100,000) tunable microwave cavity cooled with a dilution refrigerator in a 7-tesla magnetic field. The microwave photon frequency ν is a function of the unknown axion mass, so both the cavity and amplifier must be scanned over a wide frequency range. An MSA is a linear, phase-preserving amplifier consisting of a square washer loop, fabricated from a thin Nb film, incorporating two Josephson tunnel junctions with resistive shunts to prevent hysteresis. The input is coupled via a microstrip made from a square Nb coil deposited over the washer with an intervening insulating layer. Tunability is achieved by terminating the microstrip with GaAs varactors that operate below 100 mK. By varying the varactor capacitance with a bias voltage, the resonant frequency is varied by up to a factor of 2. We demonstrate several devices operating below 100 mK, matched to the discrete operating bands of ADMX at frequencies ranging from 560 MHz to 1 GHz. The MSAs exhibit gains exceeding 20 dB and the associated noise temperatures, measured with a hot/cold load, approach the standard quantum limit (hν/kB) . Supported by DOE Grants DE - FG02 - 97ER41029, DE - FG02 - 96ER40956, DE - AC52 - 07NA27344, DE - AC03 - 76SF00098, and the Livermore LDRD program.

Therapy of myeloma in vivo using marine phospholipid in combination with Agaricus blazei Murill as an immune respond activator.

PubMed

Murakawa, Kentaro; Fukunaga, Kenji; Tanouchi, Masatoshi; Hosokawa, Masashi; Hossain, Zakir; Takahashi, Koretaro

2007-01-01

Mushroom (Agaricus blazei Murill) extract has been reported to possess antitumor effects through immune activation. Here, we investigated the beneficial effects of combining A. blazei extract with marine phospholipids in comparison to A. blazei extract alone on myeloma sp2 tumor suppression when orally administrated. The experimental groups designed for sp2 tumor bearing BALB/c nu/nu mice were drinks of: (1)control; (2)1.0 mg/mL squid phospholipid liposome alone; (3)0.5 mg/mL A. blazei Murill water extract alone; (4)1.0 mg/mL squid phospholipid liposome with 0.5 mg/mL A. blazei Murill water extract in the form of those simple mixture; and (5)1.0 mg/mL squid phospholipid liposome with 0.5 mg/mL A. blazei Murill water extract partially encapsulated. Orally administrated volumes amounted to approximately 5 mL per day per mouse for all groups. A. blazei Murill water extract alone and squid phospholipid alone served groups show moderate tumor suppression with total administrations of approximately 105 mg/mouse for squid phospholipid through out the experimental term. When both A. blazei Murill water extract and squid phospholipid were administrated simultaneously in a simple mixture form, promotional effect on cancer tumor suppression was observed. And when A. blazei Murill water extract was partially encapsulated in the squid phospholipid liposomes with total administrations being 105 mg/mouse for squid phospholipid, effect on cancer tumor suppression was more pronounced. Though there was no statistically significant difference in tumor sizes between the simple mixture form administrated group i.e. group (4) and the partially encapsulated form administrated group i.e. group (5), the tumor vanished mouse was seen in the partially encapsulated form administrated group. Thus it was concluded that combinational administration of the A. blazei Murill water extract and the marine phospholipid may be useful in myeloma sp2 therapy.

Superconducting Detector Arrays for Astrophysics

NASA Technical Reports Server (NTRS)

Chervenak, James

2008-01-01

The next generation of astrophysics instruments will feature an order of magnitude more photon sensors or sensors that have an order of magnitude greater sensitivity. Since detector noise scales with temperature, a number of candidate technologies have been developed that use the intrinsic advantages of detector systems that operate below 1 Kelvin. Many of these systems employ of the superconducting phenomena that occur in metals at these temperatures to build ultrasensitive detectors and low-noise, low-power readout architectures. I will present one such system in use today to meet the needs of the astrophysics community at millimeter and x-ray wavelengths. Our group at NASA in collaboration with Princeton, NIST, Boulder and a number of other groups is building large format arrays of superconducting transition edge sensors (TES) read out with multiplexed superconducting quantum interference devices (SQUID). I will present the high sensitivity we have achieved in multiplexed x-ray sensors with the TES technology and describe the construction of a 1000-sensor TES/SQUID array for microwave measurements. With our collaboration's deployment of a kilopixel TES array for 2 mm radiation at the Atacarna Cosmology Telescope in November 2007, we have first images of the lensed Cosmic Microwave Background at fine angular scales.

The magnetic field of gastrointestinal smooth muscle activity

NASA Astrophysics Data System (ADS)

Bradshaw, Alan; Ladipo, Jk; Richards, William; Wikswo, John

1997-11-01

The gastrointestinal (GI) tract controls the absorption and transport of ingested materials. Its function is determined largely by the electrical activity of the smooth muscle that lines the GI tract. GI electrical activity consists of an omnipresent slowly oscillating wave known as the basic electrical rhythm (BER) that modulates a higher-frequency spiking activity associated with muscle contraction. The BER has been shown to be a reliable indicator of intestinal viability, and thus, recording of smooth muscle activity may have clinical value. The BER is difficult to measure with cutaneous electrodes because layers of low-conductivity fat between the GI tract and the abdominal surface attenuate the potential. On the other hand, the magnetic field associated with GI electrical activity is mostly unaffected by intervening fat layers. We recorded the magnetic fields from GI activity in 12 volunteers using a multichannel Superconducting QUantum Interference Device (SQUID) magnetometer. Characteristics typical of gastric and intestinal BER were apparent in the data. Channels near the epigastrium recorded gastric BER, and channels in intestinal areas recorded small bowel BER. These results suggest that a single multichannel SQUID magnetometer is able to measure gastrointestinal electrical activity from multiple locations around the abdomen simultaneously.

Multi-frequency modes in superconducting resonators: Bridging frequency gaps in off-resonant couplings

NASA Astrophysics Data System (ADS)

Andersen, Christian Kraglund; Mølmer, Klaus

2015-03-01

A SQUID inserted in a superconducting waveguide resonator imposes current and voltage boundary conditions that makes it suitable as a tuning element for the resonator modes. If such a SQUID element is subject to a periodically varying magnetic flux, the resonator modes acquire frequency side bands. We calculate the multi-frequency eigenmodes and these can couple resonantly to physical systems with different transition frequencies and this makes the resonator an efficient quantum bus for state transfer and coherent quantum operations in hybrid quantum systems. As an example of the application, we determine their coupling to transmon qubits with different frequencies and we present a bi-chromatic scheme for entanglement and gate operations. In this calculation, we obtain a maximally entangled state with a fidelity F = 95 % . Our proposal is competitive with the achievements of other entanglement-gates with superconducting devices and it may offer some advantages: (i) There is no need for additional control lines and dephasing associated with the conventional frequency tuning of qubits. (ii) When our qubits are idle, they are far detuned with respect to each other and to the resonator, and hence they are immune to cross talk and Purcell-enhanced decay.

Ultra-low field MRI food inspection system prototype

NASA Astrophysics Data System (ADS)

Kawagoe, Satoshi; Toyota, Hirotomo; Hatta, Junichi; Ariyoshi, Seiichiro; Tanaka, Saburo

2016-11-01

We develop an ultra-low field (ULF) magnetic resonance imaging (MRI) system using a high-temperature superconducting quantum interference device (HTS-SQUID) for food inspection. A two-dimensional (2D)-MR image is reconstructed from the grid processing raw data using the 2D fast Fourier transform method. In a previous study, we combined an LC resonator with the ULF-MRI system to improve the detection area of the HTS-SQUID. The sensitivity was improved, but since the experiments were performed in a semi-open magnetically shielded room (MSR), external noise was a problem. In this study, we develop a compact magnetically shielded box (CMSB), which has a small open window for transfer of a pre-polarized sample. Experiments were performed in the CMSB and 2D-MR images were compared with images taken in the semi-open MSR. A clear image of a disk-shaped water sample is obtained, with an outer dimension closer to that of the real sample than in the image taken in the semi-open MSR. Furthermore, the 2D-MR image of a multiple cell water sample is clearly reconstructed. These results show the applicability of the ULF-MRI system in food inspection.

Far infrared through millimeter backshort-under-grid arrays

NASA Astrophysics Data System (ADS)

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

2006-06-01

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

Superconducting six-axis accelerometer

NASA Technical Reports Server (NTRS)

Paik, H. J.

1990-01-01

A new superconducting accelerometer, capable of measuring both linear and angular accelerations, is under development at the University of Maryland. A single superconducting proof mass is magnetically levitated against gravity or any other proof force. Its relative positions and orientations with respect to the platform are monitored by six superconducting inductance bridges sharing a single amplifier, called the Superconducting Quantum Interference Device (SQUID). The six degrees of freedom, the three linear acceleration components and the three angular acceleration components, of the platform are measured simultaneously. In order to improve the linearity and the dynamic range of the instrument, the demodulated outputs of the SQUID are fed back to appropriate levitation coils so that the proof mass remains at the null position for all six inductance bridges. The expected intrinsic noise of the instrument is 4 x 10(exp -12)m s(exp -2) Hz(exp -1/2) for linear acceleration and 3 x 10(exp -11) rad s(exp -2) Hz(exp -1/2) for angular acceleration in 1-g environment. In 0-g, the linear acceleration sensitivity of the superconducting accelerometer could be improved by two orders of magnitude. The design and the operating principle of a laboratory prototype of the new instrument is discussed.

Realizing and characterizing chiral photon flow in a circuit quantum electrodynamics necklace.

PubMed

Wang, Yan-Pu; Wang, Wei; Xue, Zheng-Yuan; Yang, Wan-Li; Hu, Yong; Wu, Ying

2015-02-10

Gauge theory plays the central role in modern physics. Here we propose a scheme of implementing artificial Abelian gauge fields via the parametric conversion method in a necklace of superconducting transmission line resonators (TLRs) coupled by superconducting quantum interference devices (SQUIDs). The motivation is to synthesize an extremely strong effective magnetic field for charge-neutral bosons which can hardly be achieved in conventional solid-state systems. The dynamic modulations of the SQUIDs can induce effective magnetic fields for the microwave photons in the TLR necklace through the generation of the nontrivial hopping phases of the photon hopping between neighboring TLRs. To demonstrate the synthetic magnetic field, we study the realization and detection of the chiral photon flow dynamics in this architecture under the influence of decoherence. Taking the advantages of its simplicity and flexibility, this parametric scheme is feasible with state-of-the-art technology and may pave an alternative way for investigating the gauge theories with superconducting quantum circuits. We further propose a quantitative measure for the chiral property of the photon flow. Beyond the level of qualitative description, the dependence of the chiral flow on external pumping parameters and cavity decay is characterized.

Benchmarking for On-Scalp MEG Sensors.

PubMed

Xie, Minshu; Schneiderman, Justin F; Chukharkin, Maxim L; Kalabukhov, Alexei; Riaz, Bushra; Lundqvist, Daniel; Whitmarsh, Stephen; Hamalainen, Matti; Jousmaki, Veikko; Oostenveld, Robert; Winkler, Dag

2017-06-01

We present a benchmarking protocol for quantitatively comparing emerging on-scalp magnetoencephalography (MEG) sensor technologies to their counterparts in state-of-the-art MEG systems. As a means of validation, we compare a high-critical-temperature superconducting quantum interference device (high T c SQUID) with the low- T c SQUIDs of an Elekta Neuromag TRIUX system in MEG recordings of auditory and somatosensory evoked fields (SEFs) on one human subject. We measure the expected signal gain for the auditory-evoked fields (deeper sources) and notice some unfamiliar features in the on-scalp sensor-based recordings of SEFs (shallower sources). The experimental results serve as a proof of principle for the benchmarking protocol. This approach is straightforward, general to various on-scalp MEG sensors, and convenient to use on human subjects. The unexpected features in the SEFs suggest on-scalp MEG sensors may reveal information about neuromagnetic sources that is otherwise difficult to extract from state-of-the-art MEG recordings. As the first systematically established on-scalp MEG benchmarking protocol, magnetic sensor developers can employ this method to prove the utility of their technology in MEG recordings. Further exploration of the SEFs with on-scalp MEG sensors may reveal unique information about their sources.

A Practical HTS SQUID Magnetometer System for NDI of Aircraft

DTIC Science & Technology

1994-01-10

based on present-day high Tc SQUIDs is feasible, and present a portable design cooled by a miniature cryocooler . In addition, a reevaluation of the basic...integration of this cryocooler with SQUIDs, is that there is no available electromagnetic field emission information. We did not find any for other types ...background signals. Third, there are several other types of cryocoolers , integrated or split, made of plastics available on the market. They will

Parametric Phase-Sensitive Detector Using Two-cell SQUID

DTIC Science & Technology

2010-08-01

an attenuator of -20 dB. The microwave was fed into the coplanar resonator by a coplanar capacitance of 9 fF, and corresponding response was coupled...transmission line between the two coupled coplanar capacitances . With a network analyzer, the resonant frequency was confirmed to be 8.985 GHz and the...microwave directional sensors based on two-cell SQUIDs. Two SQUID circuits with different values of McCumber parameter βc have been tested. Observed

[Determination of proximal chemical composition of squid (dosidicus gigas) and development of gel products].

PubMed

Abugoch, L; Guarda, A; Pérez, L M; Paredes, M P

1999-06-01

The good nutritional properties of meat from big squid (Dosidicus gigas) living on the Chilean coast, was determined through its proximal composition 70 cal/100 g fresh meat; 82.23 +/- 0.98% moisture; 15.32 +/- 0.93% protein; 1.31 +/- 0.12% ashes; 0.87 +/- 0.18% fat and 0.27% NNE (non-nitrogen extract). The big squid meat was used to develop a gel product which contained NaCl and TPP. It was necessary to use additives for gel preparation, such as carragenin or alginate or egg albumin, due to the lack of gelation properties of squid meat. Formulations containing egg albumin showed the highest gel force measured by penetration as compared to those that contained carragenin or alginate.

Conformational changes in proteins recovered from jumbo squid (Dosidicus gigas) muscle through pH shift washing treatments.

PubMed

Cortés-Ruiz, Juan A; Pacheco-Aguilar, Ramón; Ramírez-Suárez, Juan C; Lugo-Sánchez, Maria E; García-Orozco, Karina D; Sotelo-Mundo, Rogerio R; Peña-Ramos, Aida

2016-04-01

Conformational and thermal-rheological properties of acidic (APC) and neutral (NPC) protein concentrates were evaluated and compared to those of squid (Dosidicus gigas) muscle proteins (SM). Surface hydrophobicity, sulfhydryl status, secondary structure profile, differential scanning calorimetry and oscillatory dynamic rheology were used to evaluate the effect of treatments on protein properties. Acidic condition during the washing process (APC) promoted structural and conformational changes in the protein present in the concentrate produced. These changes were enhanced during the heat setting of the corresponding sol. Results demonstrate that washing squid muscle under the proposed acidic conditions is a feasible technological alternative for squid-based surimi production improving its yield and gel-forming ability. Copyright © 2015. Published by Elsevier Ltd.

Electrical NEP in hot-electron titanium superconducting bolometers

NASA Astrophysics Data System (ADS)

Karasik, Boris S.; Pereverzev, Sergey V.; Olaya, David; Wei, Jian; Gershenson, Michael E.; Sergeev, Andrei V.

2008-07-01

We are presenting the current progress on the titanium (Ti) hot-electron transition-edge devices. The ultimate goal of this work is to develop a submillimeter Hot-Electron Direct Detector (HEDD) with the noise equivalent power NEP = 10-18-10-20 W/Hz1/2 for the moderate resolution spectroscopy and Cosmic Microwave Background (CMB) studies on future space telescope (e.g., SPICA, SAFIR, SPECS, CMBPol) with cryogenically cooled (~ 4-5 K) mirrors. Recentlyi, we have achieved the extremely low thermal conductance (~ 20 fW/K at 300 mK and ~ 0.1 fW/K at 40 mK) due to the electron-phonon decoupling in Ti nanodevices with niobium (Nb) Andreev contacts. This thermal conductance translates into the "phonon-noise" NEP ~ 3×10-21 W/Hz1/2 at 40 mK and NEP ~ 3×10-19 W/Hz1/2 at 300 mK. These record data indicate the great potential of the hot-electron detector for meeting many application needs. Beside the extremely low phonon-noise NEP, the nanobolometers have a very low electron heat capacitance that makes them promising as detectors of single THz photonsii. As the next step towards the practical demonstration of the HEDD, we fabricated and tested somewhat larger than in Ref.1 devices (~ 6 μm × 0.35 μm × 40 nm) whose critical temperature is well reproduced in the range 300-350 mK. The output electrical noise measured in these devices with a low-noise dc SQUID is dominated by the thermal energy fluctuations (ETF) aka "phonon noise". This indicates the high electrothermal loop gain that effectively suppresses the contributions of the Johnson noise and the amplifier (SQUID) noise. The electrical NEP = 6.7×10-18 W/Hz1/2 derived from these measurements is in good agreement with the predictions based on the thermal conductance data. The very low NEP and the high speed (~ μs) are a unique combination not found in other detectors.

Comprehensive Model of Jumbo Squid Dosidicus gigas Trophic Ecology in the Northern Humboldt Current System

PubMed Central

Alegre, Ana; Ménard, Frédéric; Tafur, Ricardo; Espinoza, Pepe; Argüelles, Juan; Maehara, Víctor; Flores, Oswaldo; Simier, Monique; Bertrand, Arnaud

2014-01-01

The jumbo squid Dosidicus gigas plays an important role in marine food webs both as predator and prey. We investigated the ontogenetic and spatiotemporal variability of the diet composition of jumbo squid in the northern Humboldt Current system. For that purpose we applied several statistical methods to an extensive dataset of 3,618 jumbo squid non empty stomachs collected off Peru from 2004 to 2011. A total of 55 prey taxa was identified that we aggregated into eleven groups. Our results evidenced a large variability in prey composition as already observed in other systems. However, our data do not support the hypothesis that jumbo squids select the most abundant or energetic taxon in a prey assemblage, neglecting the other available prey. Indeed, multinomial model predictions showed that stomach fullness increased with the number of prey taxa, while most stomachs with low contents contained one or two prey taxa only. Our results therefore question the common hypothesis that predators seek locally dense aggregations of monospecific prey. In addition D. gigas consumes very few anchovy Engraulis ringens in Peru, whereas a tremendous biomass of anchovy is potentially available. It seems that D. gigas cannot reach the oxygen unsaturated waters very close to the coast, where the bulk of anchovy occurs. Indeed, even if jumbo squid can forage in hypoxic deep waters during the day, surface normoxic waters are then required to recover its maintenance respiration (or energy?). Oxygen concentration could thus limit the co-occurrence of both species and then preclude predator-prey interactions. Finally we propose a conceptual model illustrating the opportunistic foraging behaviour of jumbo squid impacted by ontogenetic migration and potentially constrained by oxygen saturation in surface waters. PMID:24465788

Comprehensive model of Jumbo squid Dosidicus gigas trophic ecology in the Northern Humboldt current system.

PubMed

Alegre, Ana; Ménard, Frédéric; Tafur, Ricardo; Espinoza, Pepe; Argüelles, Juan; Maehara, Víctor; Flores, Oswaldo; Simier, Monique; Bertrand, Arnaud

2014-01-01

The jumbo squid Dosidicus gigas plays an important role in marine food webs both as predator and prey. We investigated the ontogenetic and spatiotemporal variability of the diet composition of jumbo squid in the northern Humboldt Current system. For that purpose we applied several statistical methods to an extensive dataset of 3,618 jumbo squid non empty stomachs collected off Peru from 2004 to 2011. A total of 55 prey taxa was identified that we aggregated into eleven groups. Our results evidenced a large variability in prey composition as already observed in other systems. However, our data do not support the hypothesis that jumbo squids select the most abundant or energetic taxon in a prey assemblage, neglecting the other available prey. Indeed, multinomial model predictions showed that stomach fullness increased with the number of prey taxa, while most stomachs with low contents contained one or two prey taxa only. Our results therefore question the common hypothesis that predators seek locally dense aggregations of monospecific prey. In addition D. gigas consumes very few anchovy Engraulis ringens in Peru, whereas a tremendous biomass of anchovy is potentially available. It seems that D. gigas cannot reach the oxygen unsaturated waters very close to the coast, where the bulk of anchovy occurs. Indeed, even if jumbo squid can forage in hypoxic deep waters during the day, surface normoxic waters are then required to recover its maintenance respiration (or energy?). Oxygen concentration could thus limit the co-occurrence of both species and then preclude predator-prey interactions. Finally we propose a conceptual model illustrating the opportunistic foraging behaviour of jumbo squid impacted by ontogenetic migration and potentially constrained by oxygen saturation in surface waters.

Complex Visual Adaptations in Squid for Specific Tasks in Different Environments

PubMed Central

Chung, Wen-Sung; Marshall, N. Justin

2017-01-01

In common with their major competitors, the fish, squid are fast moving visual predators that live over a great range of depths in the ocean. Both squid and fish show a variety of adaptations with respect to optical properties, receptors and their underlying neural circuits, and these adaptations are often linked to the light conditions of their specific niche. In contrast to the extensive investigations of adaptive strategies in fish, vision in response to the varying quantity and quality of available light, our knowledge of visual adaptations in squid remains sparse. This study therefore undertook a comparative study of visual adaptations and capabilities in a number of squid species collected between 0 and 1,200 m. Histology, magnetic resonance imagery (MRI), and depth distributions were used to compare brains, eyes, and visual capabilities, revealing that the squid eye designs reflect the lifestyle and the versatility of neural architecture in its visual system. Tubular eyes and two types of regional retinal deformation were identified and these eye modifications are strongly associated with specific directional visual tasks. In addition, a combination of conventional and immuno-histology demonstrated a new form of a complex retina possessing two inner segment layers in two mid-water squid species which they rhythmically move across a broad range of depths (50–1,000 m). In contrast to their relatives with the regular single-layered inner segment retina live in the upper mesopelagic layer (50–400 m), the new form of retinal interneuronal layers suggests that the visual sensitivity of these two long distance vertical migrants may increase in response to dimmer environments. PMID:28286484

Behavioral ecology of jumbo squid (Dosidicus gigas) in relation to oxygen minimum zones

NASA Astrophysics Data System (ADS)

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

2013-10-01

Habitat utilization, behavior and food habits of the jumbo or Humboldt squid, Dosidicus gigas, were compared between an area recently inhabited in the northern California Current System (CCS) and a historically established area of residence in the Gulf of California (GOC). Low dissolved oxygen concentrations at midwater depths define the oxygen minimum zone (OMZ), an important environmental feature in both areas. We analyzed vertical diving behavior and diet of D. gigas and hydrographic properties of the water column to ascertain the extent to which squid utilized the OMZ in the two areas. The upper boundary of the OMZ has been shoaling in recent decades in the CCS, and this phenomenon has been proposed to vertically compress the pelagic environment inhabited by aerobic predators. A shoaling OMZ will also bring mesopelagic communities into a depth range with more illumination during daytime, making these organisms more vulnerable to predation by visual predators (i.e. jumbo squid). Because the OMZ in the GOC is considerably shallower than in the CCS, our study provides insight into the behavioral plasticity of jumbo squid and how they may respond to a shoaling OMZ in the CCS. We propose that shoaling OMZs are likely to be favorable to jumbo squid and could be a key indirect factor behind the recent range expansion of this highly migratory predator.

Vestigial phragmocone in the gladius points to a deepwater origin of squid (Mollusca: Cephalopoda)

NASA Astrophysics Data System (ADS)

Arkhipkin, Alexander I.; Bizikov, Vyacheslav A.; Fuchs, Dirk

2012-03-01

The microstructure of the gladius cone was investigated in six species of nektonic squid: shallow-water Loligo gahi (Loliginidae), pelagic eurybathic Illex argentinus, Todarodes pacificus, Dosidicus gigas (Ommastrephidae), and deepwater Onykia ingens (Onychoteuthidae) and Gonatus antarcticus (Gonatidae) using state-of-the-art microscopy. Apart from L. gahi, all other species had septa-like layers in the gladius cone, which for the first time were investigated in detail and compared with those in extinct Cretaceous belemnites Hibolithes sp. and Pachyteuthis sp., and spirulid Cyrtobelus sp. It was found that the organic layers of the gladius cone in recent squid can be homologized with the organic components of the shell in fossil phragmocone-bearing coleoids. The septa-like layers in modern gladius cones therefore represent a vestigial phragmocone composed of organic septal rudiments of the ancestral phragmocone that has lost the siphuncle and gas-filled chambers. The well-developed rostrum in onychoteuthids and small rostrum of the gladius in ommastrephids and gonatids can be seen as homologous with the belemnoid rostrum, which may indicate a close phylogenetic relationship between belemnites and at least some squid. Possible evolutionary pathways of the reduction of the functional phragmocone in squid ancestors are discussed. Several features such as the loss of shell calcification, deep water speciation, and the structure of the equilibrium organ point to a deep-water origin of squids.

Measurement of SQUID noise levels for SuperCDMS SNOLAB detectors - Final Paper

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Maxwell

SuperCDMS SNOLAB is a second generation direct dark matter search. In the SuperCDMS SNOLAB experiment, detectors are able to pick up from signals from dark matter nuclear recoil interactions which occur inside the bulk of the detectors. These interactions produce both phonon and charge signals. HEMTs read out charge signals whereas TES are used to detect phonon signals which are then read out by SQUID amplifiers. SQUID amplifiers must add negligible noise to the TES intrinsic noise which has been previously measured and is approximately 50pA/√Hz down to 100Hz for ease of signal distinguishability in dark matter nuclear interactions. Themore » intrinsic noise level of the SQUID was tested in the SLAC 300mK fridge and determined to provide adequately low levels of noise with a floor of approximately 3pA/√Hz. Furthermore, a 10x amplifier was tested for addition of extraneous noise. This noise was investigated with and without this amplifier, and it was found that it did not add a significant amount of noise to the intrinsic SQUID noise.« less

Synthesis of BiFeO3 thin films by chemical solution deposition - Structural and magnetic studies

NASA Astrophysics Data System (ADS)

Angappane, S.; Kambhala, Nagaiah

2012-06-01

BiFeO3 thin films were deposited on Si (100) substrates by chemical solution deposition. A precursor solution of bismuth acetate and iron acetylacetonate dissolved in distilled water and acetic acid was spin coated on to silicon substrates at ambient conditions, followed by drying and annealing at 650 °C. The films were characterized by XRD and FESEM to study structural properties and morphology. The magnetic properties studied by SQUID magnetometer shows the ferromagnetic nature of the chemical solution deposited BiFeO3 films which are crucial for low cost device applications.

The Hawaiian bobtail squid as a model system for selective particle capture in microfluidic systems.

NASA Astrophysics Data System (ADS)

Nawroth, Janna; McFall-Ngai, Margaret; Dabiri, John

2013-11-01

Juvenile Hawaiian bobtail squids reliably capture and isolate a single species of bacteria, Vibrio fischeri, from inhaled coastal water containing a huge background of living and non-living particles of comparable size. Biochemical mechanisms orchestrate a chain of specific interactions as soon as V.fischeri attach to the squid's internal light organ. It remains unclear, however, how the bacteria carried by the squid's ventilation currents are initially attracted to the light organ's surface. Here we present preliminary experimental data showing how arrangement and coordination of the cilia covering the light organ create a 3D flow field that facilitates advection, sieving and selective retention of flow-borne particles. These studies may inspire novel microfluidic tools for detection and capture of specific cells and particles.

Development of scanning graphene Hall probes for magnetic microscopy

NASA Astrophysics Data System (ADS)

Schaefer, Brian T.; Wang, Lei; McEuen, Paul L.; Nowack, Katja C.

We discuss our progress on developing scanning Hall probes fabricated from hexagonal boron nitride (hBN)-encapsulated graphene, with the goal to image magnetic fields with submicron resolution. In contrast to scanning superconducting quantum interference device (SQUID) microscopy, this technique is compatible with a large applied magnetic field and not limited to cryogenic temperatures. The field sensitivity of a Hall probe depends inversely on carrier density, while the primary source of noise in the measurement is Johnson noise originating from the device resistance. hBN-encapsulated graphene demonstrates high carrier mobility at low carrier densities, therefore making it an ideal material for sensitive Hall probes. Furthermore, engineering the dielectric environment of graphene by encapsulating in hBN reduces low-frequency charge noise and disorder from the substrate. We outline our plans for adapting these devices for scanning, including characterization of the point spread function with a scanned current loop and fabrication of a deep-etched structure that enables positioning the sensitive area within 100 nanometers of the sample surface.

Single-crystalline FeCo nanoparticle-filled carbon nanotubes: synthesis, structural characterization and magnetic properties.

PubMed

Ghunaim, Rasha; Scholz, Maik; Damm, Christine; Rellinghaus, Bernd; Klingeler, Rüdiger; Büchner, Bernd; Mertig, Michael; Hampel, Silke

2018-01-01

In the present work, we demonstrate different synthesis procedures for filling carbon nanotubes (CNTs) with equimolar binary nanoparticles of the type Fe-Co. The CNTs act as templates for the encapsulation of magnetic nanoparticles and provide a protective shield against oxidation as well as prevent nanoparticle agglomeration. By variation of the reaction parameters, we were able to tailor the sample purity, degree of filling, the composition and size of the filling particles, and therefore, the magnetic properties. The samples were analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), superconducting quantum interference device (SQUID) and thermogravimetric analysis (TGA). The Fe-Co-filled CNTs show significant enhancement in the coercive field as compared to the corresponding bulk material, which make them excellent candidates for several applications such as magnetic storage devices.

Development of RF Sensor Based on Two-Cell Squid

DTIC Science & Technology

2011-07-15

to (8) is proportional to the reduced drive detuning, ωp0 is the resonant frequency for small oscillations, i.e. the plasma frequency of the combined...2 Φ= cnc IRπω (16) where Rn is the normal resistance of the Josephson junction in the SQUID, and L the inductance of the...were about 9 fF. The critical current I0 of each junction in the SQUID was 17.7 μA, normal resistance 110.9 Ω, plasma frequency ωp 124 GHz and