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Sample records for bobtail squid euprymna

  1. Characterizing the host and symbiont proteomes in the association between the Bobtail squid, Euprymna scolopes, and the bacterium, Vibrio fischeri.

    Directory of Open Access Journals (Sweden)

    Tyler R Schleicher

    Full Text Available The beneficial symbiosis between the Hawaiian bobtail squid, Euprymna scolopes, and the bioluminescent bacterium, Vibrio fischeri, provides a unique opportunity to study host/microbe interactions within a natural microenvironment. Colonization of the squid light organ by V. fischeri begins a lifelong association with a regulated daily rhythm. Each morning the host expels an exudate from the light organ consisting of 95% of the symbiont population in addition to host hemocytes and shed epithelial cells. We analyzed the host and symbiont proteomes of adult squid exudate and surrounding light organ epithelial tissue using 1D- and 2D-polyacrylamide gel electrophoresis and multidimensional protein identification technology (MudPIT in an effort to understand the contribution of both partners to the maintenance of this association. These proteomic analyses putatively identified 1581 unique proteins, 870 proteins originating from the symbiont and 711 from the host. Identified host proteins indicate a role of the innate immune system and reactive oxygen species (ROS in regulating the symbiosis. Symbiont proteins detected enhance our understanding of the role of quorum sensing, two-component signaling, motility, and detoxification of ROS and reactive nitrogen species (RNS inside the light organ. This study offers the first proteomic analysis of the symbiotic microenvironment of the adult light organ and provides the identification of proteins important to the regulation of this beneficial association.

  2. The Hawaiian bobtail squid (Euprymna scolopes): a model to study the molecular basis of eukaryote-prokaryote mutualism and the development and evolution of morphological novelties in cephalopods.

    Science.gov (United States)

    Lee, Patricia N; McFall-Ngai, Margaret J; Callaerts, Patrick; de Couet, H Gert

    2009-11-01

    The Hawaiian bobtail squid, Euprymna scolopes, is a cephalopod whose small size, short lifespan, rapid growth, and year-round availability make it suitable as a model organism. E. scolopes is studied in three principal contexts: (1) as a model of cephalopod development; (2) as a model of animal-bacterial symbioses; and (3) as a system for studying adaptations of tissues that interact with light. E. scolopes embryos can be obtained continually and can be reared in the laboratory over an entire generation. The embryos and protective chorions are optically clear, facilitating in situ developmental observations, and can be manipulated experimentally. Many molecular protocols have been developed for studying E. scolopes development. This species is best known, however, for its symbiosis with the luminous marine bacterium Vibrio fischeri and has been used to study determinants of symbiont specificity, the influence of symbiosis on development of the squid light organ, and the mechanisms by which a stable association is achieved. Both partners can be grown independently under laboratory conditions, a feature that offers the unusual opportunity to manipulate the symbiosis experimentally. Molecular and genetic tools have been developed for V. fischeri, and a large expressed sequence tag (EST) database is available for the host symbiotic tissues. Additionally, comparisons between light organ form and function to those of the eye can be made. Both types of tissue interact with light, but have divergent embryonic development. As such, they offer an opportunity to study the molecular basis for the evolution of morphological novelties. PMID:20150047

  3. HOX genes in the sepiolid squid Euprymna scolopes: Implications for the evolution of complex body plans

    OpenAIRE

    Callaerts, Patrick; Lee, Patricia N.; Hartmann, Britta; Farfan, Claudia; Choy, Darrett W. Y.; Ikeo, Kazuho; Fischbach, Karl-Friedrich; Gehring, Walter J.; de Couet, H. Gert

    2002-01-01

    Molluscs display a rich diversity of body plans ranging from the wormlike appearance of aplacophorans to the complex body plan of the cephalopods with highly developed sensory organs, a complex central nervous system, and cognitive abilities unrivaled among the invertebrates. The aim of the current study is to define molecular parameters relevant to the developmental evolution of cephalopods by using the sepiolid squid Euprymna scolopes as a model system. Using PCR-based approaches, we identi...

  4. Does predation risk affect mating behavior? An experimental test in dumpling squid (Euprymna tasmanica.

    Directory of Open Access Journals (Sweden)

    Amanda M Franklin

    Full Text Available INTRODUCTION: One of the most important trade-offs for many animals is that between survival and reproduction. This is particularly apparent when mating increases the risk of predation, either by increasing conspicuousness, reducing mobility or inhibiting an individual's ability to detect predators. Individuals may mitigate the risk of predation by altering their reproductive behavior (e.g. increasing anti-predator responses to reduce conspicuousness. The degree to which individuals modulate their reproductive behavior in relation to predation risk is difficult to predict because both the optimal investment in current and future reproduction (due to life-history strategies and level of predation risk may differ between the sexes and among species. Here, we investigate the effect of increased predation risk on the reproductive behavior of dumpling squid (Euprymna tasmanica. RESULTS: Females, but not males, showed a substantial increase in the number of inks (an anti-predator behavior before mating commenced in the presence of a predator (sand flathead Platycephalus bassensis. However, predation risk did not affect copulation duration, the likelihood of mating, female anti-predator behavior during or after mating or male anti-predator behavior at any time. CONCLUSIONS: Inking is a common anti-predator defense in cephalopods, thought to act like a smokescreen, decoy or distraction. Female dumpling squid are probably using this form of defense in response to the increase in predation risk prior to mating. Conversely, males were undeterred by the increase in predation risk. A lack of change in these variables may occur if the benefit of completing mating outweighs the risk of predation. Prioritizing current reproduction, even under predation risk, can occur when the chance of future reproduction is low, there is substantial energetic investment into mating, or the potential fitness payoffs of mating are high.

  5. Transcriptome analysis of the white body of the squid Euprymna tasmanica with emphasis on immune and hematopoietic gene discovery.

    Directory of Open Access Journals (Sweden)

    Karla A Salazar

    Full Text Available In the mutualistic relationship between the squid Euprymna tasmanica and the bioluminescent bacterium Vibrio fischeri, several host factors, including immune-related proteins, are known to interact and respond specifically and exclusively to the presence of the symbiont. In squid and octopus, the white body is considered to be an immune organ mainly due to the fact that blood cells, or hemocytes, are known to be present in high numbers and in different developmental stages. Hence, the white body has been described as the site of hematopoiesis in cephalopods. However, to our knowledge, there are no studies showing any molecular evidence of such functions. In this study, we performed a transcriptomic analysis of white body tissue of the Southern dumpling squid, E. tasmanica. Our primary goal was to gain insights into the functions of this tissue and to test for the presence of gene transcripts associated with hematopoietic and immune processes. Several hematopoiesis genes including CPSF1, GATA 2, TFIID, and FGFR2 were found to be expressed in the white body. In addition, transcripts associated with immune-related signal transduction pathways, such as the toll-like receptor/NF-κβ, and MAPK pathways were also found, as well as other immune genes previously identified in E. tasmanica's sister species, E. scolopes. This study is the first to analyze an immune organ within cephalopods, and to provide gene expression data supporting the white body as a hematopoietic tissue.

  6. Biodiversity among luminescent symbionts from squid of the genera Uroteuthis, Loliolus and Euprymna (Mollusca: Cephalopoda)

    OpenAIRE

    GUERRERO-FERREIRA, R. C.; Nishiguchi, M. K.

    2007-01-01

    Luminescent bacteria in the family Vibrionaceae (Bacteria: γ-Proteobacteria) are commonly found in complex, bilobed light organs of sepiolid and loliginid squids. Although morphology of these organs in both families of squid is similar, the species of bacteria that inhabit each host has yet to be verified. We utilized sequences of 16S ribosomal RNA, luciferase α-subunit (luxA) and the glyceraldehyde-3-phosphate dehydrogenase (gapA) genes to determine phylogenetic relationships between 63 stra...

  7. Characterizing the role of a bacterial consortium in the reproduction of the model symbiotic squid, Euprymna scolopes

    Science.gov (United States)

    The Euprymna scolopes – Vibrio fischeri association has been a model for the elucidation of numerous beneficial host/microbe interactions, including quorum sensing, host immune response to beneficial and environmental microbes, and symbiont specificity. Recently, the bacterial consortium contained w...

  8. Quorum Sensing in the Squid-Vibrio Symbiosis

    Directory of Open Access Journals (Sweden)

    Tim Miyashiro

    2013-08-01

    Full Text Available Quorum sensing is an intercellular form of communication that bacteria use to coordinate group behaviors such as biofilm formation and the production of antibiotics and virulence factors. The term quorum sensing was originally coined to describe the mechanism underlying the onset of luminescence production in cultures of the marine bacterium Vibrio fischeri. Luminescence and, more generally, quorum sensing are important for V. fischeri to form a mutualistic symbiosis with the Hawaiian bobtail squid, Euprymna scolopes. The symbiosis is established when V. fischeri cells migrate via flagella-based motility from the surrounding seawater into a specialized structure injuvenile squid called the light organ. The cells grow to high cell densities within the light organ where the infection persists over the lifetime of the animal. A hallmark of a successful symbiosis is the luminescence produced by V. fischeri that camouflages the squid at night by eliminating its shadow within the water column. While the regulatory networks governing quorum sensing are critical for properly regulating V. fischeri luminescence within the squid light organ, they also regulate luminescence-independent processes during symbiosis. In this review, we discuss the quorum-sensing network of V. fischeri and highlight its impact at various stages during host colonization.

  9. Photoreceptor fine structure in the bobtail goanna (Tiliqua rugosa)

    OpenAIRE

    Braekevelt, Charlie R.

    1989-01-01

    The fine structure of the retinal photoreceptors has been studied by light and electron microscopy in the bobtail goanna (Tiliqua rugosa) an Australian diurna1 lizard. The photoreceptors in this species are readily divisible into rods or cones based on morphological criteria. Single cones are the dominate cell type with a cone:rod ratio of about 80: 1. No multiple photoreceptors were present nor was a photoreceptor mosiac observed. Cones are large cells with a ...

  10. An annotated cDNA library of juvenile Euprymna scolopes with and without colonization by the symbiont Vibrio fischeri

    Directory of Open Access Journals (Sweden)

    Tong Deyan

    2006-06-01

    Full Text Available Abstract Background Biologists are becoming increasingly aware that the interaction of animals, including humans, with their coevolved bacterial partners is essential for health. This growing awareness has been a driving force for the development of models for the study of beneficial animal-bacterial interactions. In the squid-vibrio model, symbiotic Vibrio fischeri induce dramatic developmental changes in the light organ of host Euprymna scolopes over the first hours to days of their partnership. We report here the creation of a juvenile light-organ specific EST database. Results We generated eleven cDNA libraries from the light organ of E. scolopes at developmentally significant time points with and without colonization by V. fischeri. Single pass 3' sequencing efforts generated 42,564 expressed sequence tags (ESTs of which 35,421 passed our quality criteria and were then clustered via the UIcluster program into 13,962 nonredundant sequences. The cDNA clones representing these nonredundant sequences were sequenced from the 5' end of the vector and 58% of these resulting sequences overlapped significantly with the associated 3' sequence to generate 8,067 contigs with an average sequence length of 1,065 bp. All sequences were annotated with BLASTX (E-value Conclusion Both the number of ESTs generated from each library and GO categorizations are reflective of the activity state of the light organ during these early stages of symbiosis. Future analyses of the sequences identified in these libraries promise to provide valuable information not only about pathways involved in colonization and early development of the squid light organ, but also about pathways conserved in response to bacterial colonization across the animal kingdom.

  11. Japanese Bobtail: vertebral morphology and genetic characterization of an established cat breed.

    Science.gov (United States)

    Pollard, Rachel E; Koehne, Amanda L; Peterson, Carlyn B; Lyons, Leslie A

    2015-08-01

    Several cat breeds are defined by morphological variation of the tail. The Japanese Bobtail is a breed that has been accepted for registration only within the past 50 years; however, the congenital kinked tail variants defining this breed were documented in the Far East centuries ago and the cats are considered 'good luck' in several Asian cultures. The recent discovery of the mutation for the tailless Manx phenotype has demonstrated that the Japanese Bobtail does not have a causative mutation in the same gene (T-Box). Here, a simple segregation analysis of cats bred from a pedigreed Japanese Bobtail demonstrated a simple autosomal dominant mode of inheritance with variable expression of the tail length and kink placement. Unexpectedly, radiological examinations of the entire vertebral column of kink-tailed cats indicated variation from the normal vertebral feline formula (C7, T13, L7, S3, Cd20-24), including cats with mostly one reduction of thoracic vertebrae (C7, T12, L7, S3), and an average of 15.8 caudal vertebrae. A few cats had variation in the number of cervical vertebrae. Several transitional vertebrae and anomalous ribs were noted. One cat had a bifid vertebra in the tail. Most cats had hemivertebrae that were usually included in the tail kink, one of which was demonstrated by gross pathology and histopathology. The abnormal vertebral formula or the placement of the kink in the tail did not coincide with morbidity or mortality. PMID:25488973

  12. Squid Rolls

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    Ingredients: 250 grams of squid, 100 grams of broccoli. a pinch of green tea, 50 grams of bamboo shoots, 100 grams of various kinds of mushroom, 50 grams of chicken broth, chopped green union, ginger, cooking wine, salt, pep per and MSG.

  13. Holographic SQUID

    CERN Document Server

    Takeuchi, Shingo

    2013-01-01

    We propose a holographic model of the SQUID (Superconducting QUantum Interference Device) composed of two Josephson junctions connected each other in a circle with the magnetic flux penetrating the circuit of the SQUID and the supercurrents flowing in both Josephson junction. The gravity in this paper is the Einstein-Maxwell-complex scalar field model on the four-dimensional Anti-de Sitter Schwarzschild black brane geometry in which one space direction is compactified into a circle, and we arrange the profile of the coefficient of the time component of the gauge field having the role for the chemical potential of the cooper pair. The magnetic flux is involved by the rewriting of the surface integral of the magnetic field to the contour integral of the gauge field.

  14. Squid The Definitive Guide

    CERN Document Server

    Wessels, Duane

    2009-01-01

    Squid is the most popular Web caching software in use today, and it works on a variety of platforms including Linux, FreeBSD, and Windows. Written by Duane Wessels, the creator of Squid, Squid: The Definitive Guide will help you configure and tune Squid for your particular situation. Newcomers to Squid will learn how to download, compile, and install code. Seasoned users of Squid will be interested in the later chapters, which tackle advanced topics such as high-performance storage options, rewriting requests, HTTP server acceleration, monitoring, debugging, and troubleshooting Squid.

  15. The risks of Bobtail truck LPG (Liquefied Petroleum Gases) distribution in urban areas

    Energy Technology Data Exchange (ETDEWEB)

    Leal, Cesar A. [Det Norske Veritas (DNV), Oslo (Norway)], e-mail: cesar.leal@dnv.com

    2008-07-01

    The use of 'Bobtail' trucks (6 and 9 ton) for distribution of Liquefied Petroleum Gas (LPG) in Brazilian cities represents a new and mobile source of risk. In this paper, it will be presented a discussion about some of the possible accident scenarios that can occur with this kind of vehicle, with emphasis on the possible consequences (BLEVE/fireball). The goal is to spread information and call attention of Government Authorities and gas distribution companies, as well as the general public, about this source of risk. In the case of a 9 ton fireball, fatalities could be expected up to 176 m, according to TNO models. Collapse of the tank engulfed in fire is expected in 10 to 20 minutes, a too short time interval for the arrival of a fire brigade and control of the situation. Suggestions are presented for the use of insulating coating in the tanks capable of withstanding an external fire for two hours without collapsing and the realization of a risk study for estimation of the impact of the use of insulation in terms of risk reduction for the population and a comparison of risks associated to the two forms of LPG distribution. (author)

  16. The Squid Challenge.

    Science.gov (United States)

    Guillaume, Andrea M.

    1997-01-01

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

  17. Low noise SQUIDS

    International Nuclear Information System (INIS)

    The design, fabrication and limitations of very sensitive SQUID magnetometers are described. The SQUID magnetometer is based on the Josephson effect. A very low-noise niobium SQUID is described. It is fabricated with ultra-small niobium junctions with an overlapping area smaller than 1 μm2. The photolithographic technique developed for its fabrication, is described. Also an integrated system with a SQUID and a first-order gradiometer on a single substrate is presented. Calculations of the resolution of a dc SQUID containing ideal Josephson junctions according to the RSJ model are presented including a parasitic capacitance. The usefulness of the fabricated SQUIDS as well as some remarks on their performance is considered. (Auth.)

  18. The SQUID Handbook

    CERN Document Server

    Braginski, Alex I

    2006-01-01

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

  19. Vortex electronis and squids

    CERN Document Server

    2003-01-01

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

  20. Market Squid Ecology Dataset

    Data.gov (United States)

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

  1. Market Squid Population Dynamics

    Data.gov (United States)

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

  2. Subranging scheme for SQUID sensors

    Science.gov (United States)

    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.

  3. Geophysical applications of squids

    International Nuclear Information System (INIS)

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

  4. Low-noise SQUID

    Science.gov (United States)

    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.

  5. Dissect Your Squid and Eat It Too!

    Science.gov (United States)

    McGinnis, Patricia

    2001-01-01

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

  6. SQUID-based measuring systems

    International Nuclear Information System (INIS)

    A program has been developed and initiated at the Indira Gandhi Centre for Atomic Research (IGCAR) for the utilization of SQUID sensors in various application areas. DC SQUID sensors based on Nb-AlOx-Nb Josephson junctions have been designed and developed in house along with associated flux-locked loop (FLL) electronics. A compact low field SQUID magnetometer insertible in a liquid helium storage dewar has also been developed in house and is in use. Efforts to build a high field SQUID magnetometer, SQUID-DAC system, are in progress. A planar gradiometric DC SQUID sensor for non-destructive evaluation (NDE) application to be used in relatively unshielded environment has been designed and developed. An easily portable NDE cryostat with a small lift-off distance, to be used in external locations has been designed and tested. The magnetic field produced by a given two-dimensional current density distribution is inverted using the Fourier transform technique. (author)

  7. SQUID With Integral Flux Concentrator

    Science.gov (United States)

    Peters, Palmer N.; Sisk, Robert C.

    1989-01-01

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

  8. SQUIDs - ultimate magnetic sensors

    International Nuclear Information System (INIS)

    SQUIDs (Superconducting Quantum Interference Devices) have extreme electromagnetic energy sensitivity, which can be applied in a wide variety of ways. Some of these are covered in the papers representing the rest of this symposium: in this brief introductory paper we indicate the wide extent of the full range of applications to which they have been put, from bioscience to tests of General Relativity. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  9. Cryostats for SQUID magnetometers

    International Nuclear Information System (INIS)

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

  10. Principles and applications of SQUIDs

    International Nuclear Information System (INIS)

    Superconducting quantum interference devices (SQUIDs) combine flux quantization and Josephson tunneling to produce an output voltage that is periodic in the applied magnetic flux with a period of one flux quantum Phio. SQUIDs are thus flux-to-voltage transducers, and are able to detect changes in flux much smaller that Phio. Using Nb-based thin-film technology, a number of groups can now routinely fabricate dc SQUIDs with input circuits integrated on the same chip. At 4.2 Κ the dc SQUID, which operates with a constant bias current, can detect signals with an equivalent energy per unit bandwidth of a few hundred h-bar. At low frequencies, the SQUID exhibits l/f noise that originates in fluctuations in the critical current of the junctions and in the motion of magnetic flux trapped in the thin films. RF SQUIDs, which operate with an RF flux bias, are usually machined from bulk Nb, and have a typical energy sensitivity per unit bandwidth of 105 to 106 h-bar. Both types of SQUID can be used in a wide variety of applications, including magnetometers, gradiometers, susceptometers, voltmeters, RF amplifiers, gravity wave antennas, and gravity gradiometers

  11. Graphoepitaxial high-Tc SQUIDs

    International Nuclear Information System (INIS)

    The fabrication process and physical properties of graphoepitaxially engineered high-Tc direct current superconducting quantum interferometer devices (DC SQUIDs) are studied. Double buffer layers, each comprising a graphoepitaxial seed layer of YBa2Cu3O7−x and an epitaxial blocking layer of SrTiO3, were deposited over textured step edges on (001) surfaces of MgO substrates. Scanning electron microscopy and high-resolution transmission electron microscopy were used to investigate the microstructural properties of DC SQUIDs with graphoepitaxial Josephson junctions. Both direct coupled and inductively coupled high-Tc DC SQUIDs with graphoepitaxial step edge junctions and flux transformers were studied.

  12. Understanding the Role of Host Hemocytes in a Squid/Vibrio Symbiosis Using Transcriptomics and Proteomics

    Directory of Open Access Journals (Sweden)

    Andrew J. Collins

    2012-05-01

    Full Text Available The symbiosis between the squid, Euprymna scolopes, and the bacterium, Vibrio fischeri, serves as a model for understanding interactions between beneficial bacteria and animal hosts. The establishment and maintenance of the association is highly specific and depends on the selection of V. fischeri and exclusion of non-symbiotic bacteria from the environment. Current evidence suggests that the host’s cellular innate immune system, in the form of macrophage-like hemocytes, helps to mediate host tolerance of V. fischeri. To begin to understand the role of hemocytes in this association, we analyzed these cells by high-throughput 454 transcriptomic and liquid chromatography/ tandem mass spectrometry (LC-MS/MS proteomic analyses. 454 high-throughput sequencing produced 650,686 reads totaling 279.9 Mb while LC-MS/MS analyses of circulating hemocytes putatively identified 702 unique proteins. Several receptors involved with the recognition of microbial associated molecular patterns (MAMPs were identified. Among these was a complete open reading frame (ORF to a putative peptidoglycan recognition protein (EsPGRP5 that has conserved residues for amidase activity. Assembly of the hemocyte transcriptome showed EsPGRP5 had high coverage, suggesting it is among the 5% most abundant transcripts in circulating hemocytes. Other transcripts and proteins identified included members of the conserved NFκB signaling pathway, putative members of the complement pathway, the carbohydrate binding protein galectin, and cephalotoxin. Quantitative PCR of complement-related genes, cephalotoxin, EsPGRP5, and a nitric oxide synthase showed differential expression in circulating hemocytes isolated from adult squid with colonized light organs compared to those for which the symbionts were removed. These data suggest that the presence of the symbiont influences gene expression of the cellular innate immune system of the host.

  13. SQUID-based measuring systems

    Indian Academy of Sciences (India)

    M P Janawadkar; R Baskaran; R Nagendran; K Gireesan; N Harishkumar; Rita Saha; L S Vaidhyanathan; J Jayapandian; Y Hariharan; T S Radhakrishnan

    2002-05-01

    A program has been developed and initiated at the Indira Gandhi Centre for Atomic Research (IGCAR) for the utilization of SQUID sensors in various application areas. DC SQUID sensors based on Nb–AlO–Nb Josephson junctions have been designed and developed inhouse along with associated flux-locked loop (FLL) electronics. A compact low field SQUID magnetometer insertible in a liquid helium storage dewar has also been developed inhouse and is in use. Efforts to build a high field SQUID magnetometer, SQUID-DAC system, are in progress. A planar gradiometric DC SQUID sensor for non-destructive evaluation (NDE) application to be used in relatively unshielded environment has been designed and developed. An easily portable NDE cryostat with a small lift-off distance, to be used in external locations has been designed and tested. The magnetic field produced by a given two-dimensional current density distribution is inverted using the Fourier transform technique.

  14. Squid rocket science: How squid launch into air

    Science.gov (United States)

    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.

  15. Paleomagnetic Analysis Using SQUID Microscopy

    Science.gov (United States)

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

    2007-01-01

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

  16. Recent developments in SQUID NDE

    Science.gov (United States)

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

    2002-03-01

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

  17. SQUID holder with high magnetic shielding

    Science.gov (United States)

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

    1990-01-01

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

  18. A holographic model of SQUID

    CERN Document Server

    Cai, Rong-Gen; Zhang, Hai-Qing

    2013-01-01

    We construct a holographic model of superconducting quantum interference device (SQUID) in the Einstein-Maxwell-complex scalar theory with a negative cosmological constant. The SQUID ring consists of two Josephson junctions which sit on two sides of a compactified spatial direction of a Schwarzschild-AdS black brane. These two junctions interfere with each other and then result in a total current depending on the magnetic flux, which can be deduced from the phase differences of the two Josephson junctions. The relation between the total current and the magnetic flux is obtained numerically.

  19. High-resoution SQUID magnetometer

    Czech Academy of Sciences Publication Activity Database

    Tsoy, G. M.; Janů, Zdeněk; Novák, Miloslav; Soukup, František; Tichý, Rudolf

    284-288, - (2000), s. 2122-2123. ISSN 0921-4526 R&D Projects: GA AV ČR IAA1010832 Institutional research plan: CEZ:AV0Z1010914 Keywords : magnetic susceptibility * SQUID * magnetometer Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.893, year: 2000

  20. Cold SQUIDs and hot samples

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-05-01

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

  1. Cold SQUIDs and hot samples

    International Nuclear Information System (INIS)

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

  2. Improved Sensing Coils for SQUIDs

    Science.gov (United States)

    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.

  3. Mobile high-Tc DC SQUID magnetometer

    International Nuclear Information System (INIS)

    By optimizing the designing, we made a small size and low noise high-Tc DC SQUID readout electronics with the modulation frequency of 80 kHz. The white flux noise was about 30 μPHI0/√Hz when Sumitomo high-Tc DC SQUID sensor was used. We also proved mobile high-Tc DC SQUID magnetometer was feasible. By using a special compensation method, the SQUID magnetometer could keep locking when it swung about 20 degree sign in the earth field. Using this system and eddy-current nondestructive evaluation method, we successfully detected the defect in ferromagnetic material

  4. Biofunctional Properties of Enzymatic Squid Meat Hydrolysate

    Science.gov (United States)

    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

  5. HTS SQUID gradiometer for application without shielding

    International Nuclear Information System (INIS)

    An HTS SQUID gradiometer consisting of a series gradiometer pickup loop in flip-chip configuration with a small washer SQUID is presented. The series gradiometer configuration is advantageous for applications without shielding because of the avoidance of circulating shielding currents in the pickup loop. With a 20 mm x 10 mm substrate for the pickup loop a large effective area of 1.25 mm2 and a gradiometer baseline of 9.6 mm are achieved. The balance of the gradiometer impaired by the washer read-out SQUID can significantly be enhanced by the weighted subtraction of a reference SQUID's signal. With this a balance of 5x104 is reached. The noise-limited magnetic field gradient resolution of the balanced SQUID gradiometer is 38 fT cm-1 Hz-1/2. (author)

  6. SQUID Multiplexers for Cryogenic Detector Arrays

    Science.gov (United States)

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

    2004-01-01

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

  7. Dc SQUIDs with asymmetric shunt resistors

    International Nuclear Information System (INIS)

    We have investigated asymmetrically shunted Nb/Al-AlOx/Nb dc SQUIDs. Simulations based on the coupled Langevin equations predict that the optimum energy resolution ε, and thus also the noise performance of such an asymmetric SQUID, can be 3-4 times better than that of its symmetric counterpart. While keeping the total resistance R identical to a comparable symmetric SQUID with R-1 = R1-1 + R2-1, we shunted only one of the two Josephson junctions with R = R1,2/2. Both types of SQUIDs were characterized with respect to their transport and noise properties at temperature T = 4.2 K, and we compared the experimental results with numerical simulations. Experiments yielded ε ∼ 32 ℎ for an asymmetric SQUID with an inductance L = 22 pH, whereas a comparable symmetric device achieved ε = 110 ℎ.

  8. Low field electron paramagnetic resonance imaging with SQUID detection

    Science.gov (United States)

    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.

  9. HTS SQUID gradiometry for magnetocardiography

    International Nuclear Information System (INIS)

    Full text: Measurements of the magnetic signal of the human heart (magnetocardiography, MCG) are generally performed inside magnetically shielded rooms. This is the best known method to suppress environmental noise mainly caused by power line disturbances. As these rooms are expensive and immobile it is desirable to record MCGs outside shielding. Therefore, HTS SQUID gradiometers with additional filter techniques have been developed. Low-pass filters with cut-off frequencies of less than 130 Hz and additional notch filters are commonly employed. Since notch filters destroy signal information, and standards for data-acquisition and analysis of high resolution ECG and MCG measurements recommend a bandwidth of 250 Hz without the use of notch filters, improved noise cancellation techniques are required . We have applied a software gradiometry method to analyse the MCG data recorded with a signal and a reference HTS SQUID magnetometer outside magnetic shielding. The method uses adaptive frequency dependent gradiometer coefficients determined in the Fourier domain to subtract the reference from the signal data. The analysed MCG data sets showed improved signal to noise ratios as compared to the data recorded with an electronic gradiometer. In this way, it is possible to increase the bandwidth from 130 Hz for our electronic gradiometer to 250 Hz without using any additional filtering

  10. First demonstration of transcontinental SQUID magnetometry (Invited)

    Science.gov (United States)

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

    2013-12-01

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

  11. Aperture effects in squid jet propulsion.

    Science.gov (United States)

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

    2014-05-01

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

  12. Low-Tc, ramp-type Josephson junctions for SQUIDS

    OpenAIRE

    Podt, M.; Rolink, B.G.A.; Flokstra, J.; Rogalla, H.

    2002-01-01

    The Josephson tunnel junction is the basic element of a superconducting quantum interference device (SQUID). Amongst other parameters, the junction capacitance determines the characteristics of a (digital) SQUID. In a conventional dc SQUID, reducing the junction capacitance decreases the flux noise of the sensor, whereas in digital SQUIDs, the operating frequency can be increased when reducing the junction capacitance. For digital SQUIDs, this means that not only the flux noise decreases, but...

  13. Review of SQUID Sensors for Measuring Magnetocardiography

    International Nuclear Information System (INIS)

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

  14. Review of SQUID Sensors for Measuring Magnetocardiography

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-08-15

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

  15. Noise studies of uncoupled dc-SQUIDs

    International Nuclear Information System (INIS)

    We have performed noise measurements of uncoupled dc SQUIDs with similar square washer geometries. Mappings consisting of hundreds of flux noise measurements at different points of operation have been carried out using a dc SQUID preamplifier and a computer controlled measurement system. The white and low frequency noise, dynamic resistance, and the flux-to-voltage transfer function have been measured. The dc SQUID noise performance is described using equivalent current noise sources, and the voltage noise is observed to be linearly proportional to dynamic resistance Rdyn. (orig.)

  16. Biofunctional Properties of Enzymatic Squid Meat Hydrolysate

    OpenAIRE

    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...

  17. North Pacific High Seas Squid Jig Logbook

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This is a federally mandated logbook program high seas squid jig fishing, and it is required to be mailed in to PIFSC after a fishing trip. Fishing occurs in the...

  18. NB weak links for SQUID applications

    International Nuclear Information System (INIS)

    Ultra low noise thin film DC SQUIDs have been constructed with Josephson elements consisting of either all-Nb tunnel junctions or very narrow variable thickness bridges (nanobridges). Tunnel junctions consisting of a Nb base electrode with a Pb-alloy counter electrode have also been studied. These SQUIDs are very small in size with tunnel junctions typically 1 μm by 1 μm and nanobridges 0.25 μm long, 50 nm wide and 30 nm thick. Junctions as small as 0.3 μm x 0.3 μm and bridges as short as 0.12 μm have also been fabricated. The use of Nb thin films, particularly in the case of the tunnel junction SQUID, has led to increased ruggedness and resistance to failure during temperature cycling. Special substrates designed for transmission electron microscopy (TEM) are used for the bridge SQUIDs. (orig.)

  19. Epitaxial thick film high-Tc SQUIDs

    International Nuclear Information System (INIS)

    Low-noise operation of superconducting quantum interference devices (SQUIDs) in magnetic fields requires high critical current and strong pinning of vortices in the superconducting electrodes and in the flux transformer. Crack-free epitaxial high-Tc dc-SQUID structures with a total thickness ?5 μm and a surface roughness determined by 30 nm high growth spirals were prepared with YBa2Cu3O7-x (YBCO) films on MgO substrates buffered by a SrTiO3/BaZrO3-bilayer. HRTEM demonstrated a high quality epitaxial growth of the films. The YBCO films and SQUID structures deposited on the buffered MgO substrates had a superconducting transition temperature Tc exceeding 91 K and critical current densities Jc > 3 MA/cm2 at 77 K up to a thickness ∼5 μm. The application of thicker superconducting and insulator films helped us to increase the critical current and dynamic range of the multilayer high-Tc flux transformer and improve the insulation between the superconducting layers. An optimization of SQUID inductance allowed us to fabricate 8 mm SQUID magnetometers with SQUID voltage swings of ∼60 μV and a field resolution of ∼30 fT/√Hz at 77 K

  20. Development of Biomimetic Squid-Inspired Suckers

    Institute of Scientific and Technical Information of China (English)

    Jinping Hou; Edward Wright; Richard H. C. Bonser; George Jeronimidis

    2012-01-01

    Biomechanical properties of squid suckers were studied to provide inspiration for the development of sucker artefacts for a robotic octopus.Mechanical support of the rings found inside squid suckers was studied by bending tests.Tensile tests were carried out to study the maximum possible sucking force produced by squid suckers based on the strength of sucker stalks,normalized by the sucking areas.The squid suckers were also directly tested to obtain sucking forces by a special testing arrangement.Inspired by the squid suckers,three types of sucker artefacts were developed for the arm skin of an octopus inspired robot.The first sucker artefact made of knitted nylon sheet reinforced silicone rubber has the same shape as the squid suckers.Like real squid suckers,this type of artefact also has a stalk that is connected to the arm skin and a ring to give radial support.The second design is a straight cylindrical structure with uniform wall thickness made of silicone rubber.One end of the cylinder is directly connected to the arm skin and the other end is open.The final design of the sucker has a cylindrical base and a concave meniscus top.The meniscus was formed naturally using the surface tension of silicone gel,which leads to a higher level of the liquid around the edge of a container.The wall thickness decreases towards the tip of the sucker opening.Sucking forces of all three types of sucker artefacts were measured.Advantages and disadvantages of each sucker type were discussed.The final design of suckers has been implemented to the arm skin prototypes.

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

    DEFF Research Database (Denmark)

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

    1993-01-01

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

  2. Squid – a simple bioinformatics grid

    Directory of Open Access Journals (Sweden)

    de Miranda Antonio B

    2005-08-01

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

  3. Suppression of the critical current of a balanced SQUID

    OpenAIRE

    Kemppinen, Antti; Manninen, Antti J.; Möttönen, Mikko; Vartiainen, Juha J.; Peltonen, Joonas T.; Pekola, Jukka P.

    2007-01-01

    We present an experimental study of the magnetic flux dependence of the critical current of a balanced SQUID with three Josephson junctions in parallel. Unlike for ordinary dc SQUIDs, the suppression of the critical current does not depend on the exact parameters of the Josephson junctions. The suppression is essentially limited only by the inductances of the SQUID loops. We demonstrate a critical current suppression ratio of higher than 300 in a balanced SQUID with a maximum critical current...

  4. Flux modulation scheme for direct current SQUID readout revisited

    Science.gov (United States)

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

    2016-02-01

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

  5. Squids: principles and basic applications in experimental physics

    International Nuclear Information System (INIS)

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

  6. SQUID method of lung contamination testing

    Science.gov (United States)

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

    2006-03-01

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

  7. SQUID method of lung contamination testing

    International Nuclear Information System (INIS)

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

  8. High Tc Josephson Junctions, SQUIDs and magnetometers

    International Nuclear Information System (INIS)

    There has recently been considerable progress in the state-of-the-art of high-Tc magnetometers based on dc SQUIDs (Superconducting Quantum Interference Devices). This progress is due partly to the development of more manufacturable Josephson junctions, making SQUIDs easier to fabricate, and partly to the development of multiturn flux transformers that convert the high sensitivity of SQUIDs to magnetic flux to a correspondingly high sensitivity to magnetic field. Needless to say, today's high-Tc SQUIDs are still considerably less sensitive than their low-Tc counterparts, particularly at low frequencies (f) where their level of 1/f noise remains high. Nonetheless, the performance of the high-Tc devices has now reached the point where they are adequate for a number of the less demanding applications; furthermore, as we shall see, at least modest improvements in performance are expected in the near future. In this article, the author outlines these various developments. This is far from a comprehensive review of the field, however, and, apart from Sec. 2, he describes largely his own work. He begins in Sec. 2 with an overview of the various types of Josephson junctions that have been investigated, and in Sec. 3, he describes some of the SQUIDs that have been tested, and assess their performance. Section 4 discuss the development of the multilayer structures essential for an interconnect technology, and, in particular, for crossovers and vias. Section 5 shows how this technology enables one to fabricate multiturn flux transformers which, in turn, can be coupled to SQUIDs to make magnetometers. The performance and possible future improvements in these magnetometers are assessed, and some applications mentioned

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

    Science.gov (United States)

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

    2004-03-01

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

  10. Measuring the absolute magnetic field using high-Tc SQUID

    International Nuclear Information System (INIS)

    SQUID normally can only measure the change of magnetic field instead of the absolute value of magnetic field. Using a compensation method, a mobile SQUID, which could keep locked when moving in the earth's magnetic field, was developed. Using the mobile SQUID, it was possible to measure the absolute magnetic field. The absolute value of magnetic field could be calculated from the change of the compensation output when changing the direction of the SQUID in a magnetic field. Using this method and the mobile SQUID, we successfully measured the earth's magnetic field in our laboratory

  11. Crystallization and crystal properties of squid rhodopsin

    OpenAIRE

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

    2007-01-01

    Truncated rhodopsin from the retina of the squid Todarodes pacificus was extracted and crystallized by the sitting-drop vapour-diffusion method. Hexagonal crystals grown in the presence of octylglucoside and ammonium sulfate diffracted to 2.8 Å resolution.

  12. An automatic frequency-sweeping SQUID susceptometer

    NARCIS (Netherlands)

    Overweg, J.A.; Brake, ter H.J.M.; Flokstra, J.; Gerritsma, G.J.

    1983-01-01

    A new, SQUID-based, measuring system has been developed for the investigation of the dynamic properties of magnetic materials. Its main advantages, compared to conventional mutual inductance systems, are its high sensitivity and its nearly frequency independent response, down to extremely low freque

  13. SQUID systems for bio magnetic imaging

    International Nuclear Information System (INIS)

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

  14. One Period of Exploration with the Squid.

    Science.gov (United States)

    Bradley, James V.; Ng, Andrew

    1997-01-01

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

  15. Squid Dissection: From Pen to Ink.

    Science.gov (United States)

    Brown, Cindy; Kisiel, Jim

    2003-01-01

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

  16. TOPICAL REVIEW: SQUID systems for biomagnetic imaging

    Science.gov (United States)

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

    2001-07-01

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

  17. SQUIDs for the characterization of magnetic nanoparticles; SQUIDs fuer die Charakterisierung magnetischer Nanoteilchen

    Energy Technology Data Exchange (ETDEWEB)

    Guillaume, Alexander

    2015-07-01

    Magnetic nanoparticles (MNP) are superparamagnetic particles with a core diameter in the nm-range. The MNPs have manifold properties which make them an interesting tool for various applications. Certain parameters, such as size or size distribution and structural properties, must be well known for these applications. In this work, the dynamic behavior of MNPs was investigated by magnetorelaxometry (MRX) at a temperature of 77 K. MRX is based on the alignment of the moment of individual MNPs in parallel to a large enough magnetization field. After switching of the field, the magnetization decays with a characteristic time constant. The measurement of the relaxation can e.g. be used to calculate the size distribution of a given MNP sample. Superconducting quantum interference devices (SQUID) based on the high-T{sub c} superconductor yttrium barium copper oxide (YBCO) were employed in this work as sensors for the magnetic field. The fabrication of the superconducting and isolating thin films was carried out by pulsed laser deposition (PLD) and optimized by methods of experimental design. Several types of directly coupled SQUIDs were fabricated from the thin films by optical lithography and argon ion etching. An existing MRX setup with fluxgates was modified to allow measurements with the directly coupled SQUIDs at 77 K. After the characterization of the system, MRX measurements were performed. The relaxation of an amount of approximately 100 billion MNPs was detected at a distance of 5 mm to the SQUID. In order to reduce the minimum detectable amount of MNPs and to minimize disturbances, a novel type of SQUID was developed, fabricated and characterized. A compensation factor of up to 195 was experimentally demonstrated with this self-compensating SQUID. MNP samples were prepared directly on the SQUID by electron beam lithography. Thereby, an amount of 167 MNPs could be detected. The limit for the measurement setup was evaluated as 58 MNPs. Finite element method (FEM

  18. Quantum logic gates operation using SQUID qubits in bimodal cavity

    Institute of Scientific and Technical Information of China (English)

    Song Ke-Hui

    2006-01-01

    We present a scheme to realize the basic two-qubit logic gates such as the quantum phase gate and SWAP gate using a detuned microwave cavity interacting with three-level superconducting-quantum-interference-device (SQUID) qubit(s), by placing SQUID(s) in a two-mode microwave cavity and using adiabatic passage methods. In this scheme, the two logical states of the qubit are represented by the two lowest levels of the SQUID, and the cavity fields are treated as quantized. Compared with the previous method, the complex procedures of adjusting the level spacing of the SQUID and applying the resonant microwave pulse to the SQUID to create transformation are not required. Based on superconducting device with relatively long decoherence time and simplified operation procedure, the gates operate at a high speed, which is important in view of decoherence.

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

    Science.gov (United States)

    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.

  20. Coupled Serial and Parallel Non-uniform SQUIDs

    International Nuclear Information System (INIS)

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

  1. Multichannel applications of double relaxation oscillation Squids

    International Nuclear Information System (INIS)

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

  2. SQUID-based multichannel system for Magnetoencephalography

    CERN Document Server

    Rombetto, S; Vettoliere, A; Trebeschi, A; Rossi, R; Russo, M

    2013-01-01

    Here we present a multichannel system based on superconducting quantum interference devices (SQUIDs) for magnetoencephalography (MEG) measurements, developed and installed at Istituto di Cibernetica (ICIB) in Naples. This MEG system, consists of 163 full integrated SQUID magnetometers, 154 channels and 9 references, and has been designed to meet specifications concerning noise, dynamic range, slew rate and linearity through optimized design. The control electronics is located at room temperature and all the operations are performed inside a Magnetically Shielded Room (MSR). The system exhibits a magnetic white noise level of approximatively 5 fT/Hz1=2. This MEG system will be employed for both clinical and routine use. PACS numbers: 74.81.Fa, 85.25.Hv, 07.20.Mc, 85.25.Dq, 87.19.le, 87.85.Ng

  3. Practical SQUID Instrument for Nondestructive Testing

    Science.gov (United States)

    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.

  4. In-focal-plane SQUID multiplexer

    International Nuclear Information System (INIS)

    Superconducting quantum interference device (SQUID) multiplexers make it possible to build arrays of thousands of microcalorimeters and bolometers based on superconducting transition-edge sensors (TES) with a manageable number of readout channels. Previous to this work, TES arrays were multiplexed by extracting leads from each pixel to multiplexer filter and switching elements outside of the focal plane. As the number of pixels is increased in a close-packed array, it becomes difficult to route the leads to the multiplexer. We report on the development of an in-focal-plane SQUID multiplexer to solve this problem. In this circuit, the filter and switching elements associated with each pixel fit within the pixel area so that signals are multiplexed before being extracted from the focal plane. This in-focal-plane architecture will first be used in the SCUBA-2 instrument at the James Clerk Maxwell Telescope in 2006

  5. Biomagnetism using SQUIDs: status and perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Sternickel, Karsten [CardioMag Imaging, Inc., 450 Duane Avenue, Schenectady, NY 12304 (United States); Braginski, Alex I [Research Center Juelich, ISG-2, D-52425 Juelich (Germany)

    2006-03-15

    Biomagnetism involves the measurement and analysis of very weak local magnetic fields of living organisms and various organs in humans. Such fields can be of physiological origin or due to magnetic impurities or markers. This paper reviews existing and prospective applications of biomagnetism in clinical research and medical diagnostics. Currently, such applications require sensitive magnetic SQUID sensors and amplifiers. The practicality of biomagnetic methods depends especially on techniques for suppressing the dominant environmental electromagnetic noise, and on suitable nearly real-time data processing and interpretation methods. Of the many biomagnetic methods and applications, only the functional studies of the human brain (magnetoencephalography) and liver susceptometry are in clinical use, while functional diagnostics of the human heart (magnetocardiography) approaches the threshold of clinical acceptance. Particularly promising for the future is the ongoing research into low-field magnetic resonance anatomical imaging using SQUIDs.

  6. Multichannel applications of double relaxation oscillation SQUIDs

    Science.gov (United States)

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

    2001-12-01

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

  7. Arbitrary rotation and entanglement of flux SQUID qubits

    CERN Document Server

    Kis, Z

    2003-01-01

    We propose a new approach for the arbitrary rotation of a three-level SQUID qubit and describe a new strategy for the creation of coherence transfer and entangled states between two three-level SQUID qubits. The former is succeeded by exploring the coupled-uncoupled states of the system when irradiated with two microwave pulses, and the latter is succeeded by placing the SQUID qubits into a microwave cavity and used adiabatic passage methods for their manipulation.

  8. SQUID based multichannel system for brain functional imaging

    OpenAIRE

    Vettoliere, Antonio

    2012-01-01

    A multichannel system for brain imaging containing 163 SQUID magnetometers arranged in a helmet shaped multisensorial array has been developed. To this aim, a previous investigation of a several SQUID configurations has been performed in order to choose a SQUID sensor having best performance for brain imaging on the basis of system working conditions. In particular, magnetometer and planar gradiometer have been designed, fabricated and characterized. Furthermore, a small magnetometer has b...

  9. Performance of multiplexed SQUID readout for Cryogenic Sensor Arrays

    Science.gov (United States)

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

    2000-04-01

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

  10. Superconducting Nanobridge SQUID Magnetometer for Spin Sensing

    OpenAIRE

    Antler, Natania

    2014-01-01

    As the cutting edge of science and technology pushes towards smaller length scales, sensing technologies with nanoscale precision become increasingly important. In this thesis I will discuss the optimization and application of a 3D nanobridge SQUID magnetometer for studying solid state spin systems, in particular for sensing impurity spins in diamond. Solid state spins have proposed applications in memory and computation for both classical and quantum computing. Isolated spins typically have ...

  11. Multimodal Optimization by Sparkling Squid Populations

    OpenAIRE

    Seksaria, Videh

    2014-01-01

    The swarm intelligence of animals is a natural paradigm to apply to optimization problems. Ant colony, bee colony, firefly and bat algorithms are amongst those that have been demonstrated to efficiently to optimize complex constraints. This paper proposes the new Sparkling Squid Algorithm (SSA) for multimodal optimization, inspired by the intelligent swarm behavior of its namesake. After an introduction, formulation and discussion of its implementation, it will be compared to other popular me...

  12. Cross-linking Chemistry of Squid Beak*

    OpenAIRE

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

    2010-01-01

    In stark contrast to most aggressive predators, Dosidicus gigas (jumbo squids) do not use minerals in their powerful mouthparts known as beaks. Their beaks instead consist of a highly sclerotized chitinous composite with incremental hydration from the tip to the base. We previously reported l-3,4-dihydroxyphenylalanine (dopa)-histidine (dopa-His) as an important covalent cross-link providing mechanical strengthening to the beak material. Here, we present a more complete characterization of th...

  13. Optimized SQUID sensors for low frequency measurements

    International Nuclear Information System (INIS)

    We have fabricated and measured optimized SQUID sensors (superconducting quantum interference device) for low frequency measurements of magnetic field. We have also investigated the dependence of flux trapping field on the position of Josephson junctions with respect to the Ketchen-type washer. The sensors are measured using direct room temperature readout utilizing noise cancellation techniques based on negative and positive feedback. A superconducting magnesium diboride can is used to shield the sample in pulse-tube cryocooler measurements.

  14. Directly coupled YBCO dc SQUID magnetometers

    International Nuclear Information System (INIS)

    YBa2Cu3O7-x magnetometers have been made on 10mmx10mm MgO substrates by directly coupling the magnetometer pick-up loop to a dc SQUID with narrow strip lines. The dc SQUIDs were made with YBa2Cu3O7-x step-edge Josephson junctions. The layout of the magnetometer pick-up loop was chosen as a compromise between maximizing the loop effective area and minimizing the loop inductance. The SQUID was designed to have LS∼100 pH in order to obtain βL=2I0LS/Φ0 approx.= 1 with the single-junction critical current I0∼10 μA. We have made magnetometers with white noise levels down to 55 fT Hz-1/2 and a 1/f knee at 1 Hz (ac biased). Noise measurements were made on a field-cooled magnetometer. The noise measured at 1 Hz when cooled in 'zero field' was 175 fT Hz-1/2. When cooled in magnetic fields of B = 50 μT and B = 100 μT we measured the noise at 1 Hz to be 430 fT Hz-12 and 1.3 pT Hz-1/2, respectively. (author)

  15. Transparency and Coherence in rf SQUID Metamaterials

    Science.gov (United States)

    Anlage, Steven; Trepanier, Melissa; Zhang, Daimeng

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

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

    International Nuclear Information System (INIS)

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

  17. Low Field Squid MRI Devices, Components and Methods

    Science.gov (United States)

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

    2014-01-01

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

  18. SQUID '80: Superconducting quantum interference devices and their applications

    International Nuclear Information System (INIS)

    The nine invited lectures and 64 contributed papers collected in this volume provide an overview on the last four years of research and development work in the field of Josephson junctions. The main chapters are: Josephson junction physics, junctions and circuit noise, junction and circuit fabrication, cryogenic techniques, SQUID applications in low frequency devices, SQUID applications in geophysics, junctions and SQUID applications in microwave devices, and summary and conclusions. Lectures and papers on SQUID applications in biomagnetism have been excluded here and will be published in a separat volume. (WRI)

  19. DC SQUID amplifier for NMR experiments on small samples

    International Nuclear Information System (INIS)

    Low noise preamplifiers are required for the detection of the magnetic resonance of small size samples or at low magnetic fields. According to calculations based on the en, in model. SQUID based amplifiers are more suitable to NMR experiments on small samples than semiconductor amplifiers. We propose an amplification method by frequency transposition using a DC SQUID. Such a system can be run over a broad range of frequency as the noise impedance of the stages subsequent to the SQUID is continually optimised. The measurements are in good agreement with our theoretical model, based on a simplified voltage to flux SQUID characteristic. (orig.)

  20. Effect of parasitic capacitance on dc SQUID performance

    International Nuclear Information System (INIS)

    This paper reports on the effect of parasitic capacitance Cp on dc SQUID characteristics and noise performance studied using a test structure consisting of 11 identical SQUID washers with Nb films of various widths covering the slit. The measured IV characteristics are in good agreement with simulations based on a simple lumped circuit model

  1. SQUID magnetometry from nanometer to centimeter length scales

    International Nuclear Information System (INIS)

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

  2. SQUID magnetometry from nanometer to centimeter length scales

    Energy Technology Data Exchange (ETDEWEB)

    Hatridge, Michael J.

    2010-06-28

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

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

    International Nuclear Information System (INIS)

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

  4. SQUID magnetometry from nanometer to centimeter length scales

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-06-01

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

  5. A SQUID gradiometer module with large junction shunt resistors

    International Nuclear Information System (INIS)

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

  6. Application of SQUID for NDE and biomagnetism measurement

    International Nuclear Information System (INIS)

    SQUID is the most sensitive magnetic sensor known. It is able to detect the magnetic field as small as few femto Tesla (fT), which is equivalent to one of 10 billionth of earth magnetic field (about 50μT). SQUID can be applied in the various fields and its need will be increased greatly in the future. If SQUID is applied in the medical technology, there will be improvement in accurate diagnosis of brain and heart by supplying more information about the functions of such human organs. The nondestructive evaluation (NDE) of deep-lying flaws in the inner layer of lab jointed structures of aircraft, which is very difficult with the existing method became possible using high Tc. SQUID. In this paper, the current status of SQUID applications in both medical and NDE fields will be reviewed.

  7. Multichannel SQUID systems for particle physics experiments

    Energy Technology Data Exchange (ETDEWEB)

    Henry, S. [University of Oxford, Department of Physics, Keble Road, Oxford, OX1 3RH (United Kingdom)]. E-mail: s.henryl@physics.ox.ac.uk; Divakar, U. [University of Oxford, Department of Physics, Keble Road, Oxford, OX1 3RH (United Kingdom); Kraus, H. [University of Oxford, Department of Physics, Keble Road, Oxford, OX1 3RH (United Kingdom); Majorovits, B. [University of Oxford, Department of Physics, Keble Road, Oxford, OX1 3RH (United Kingdom)

    2006-04-15

    We have developed multichannel SQUID systems for two particle physics experiments: a 66-channel system for detector readout in the CRESST dark matter search, and a 12-channel magnetometry system for the CryoEDM neutron electric dipole moment experiment. These different applications have different requirements, for example in the CRESST system it is important to minimise crosstalk, while the CryoEDM system must be shielded from magnetic noise. Future experiments such as the EURECA dark matter project may require systems with a much higher number of channels.

  8. Development and applications of the tunnel junction dc SQUID

    International Nuclear Information System (INIS)

    The development of a cylindrical dc SQUID made with shunted Nb-NbOx-Pb Josephson tunnel junctions is described. The SQUID is current biased at a non-zero voltage, and modulated with a 100 KHz flux. The 100 KHz signal across the SQUID drives a cooled tank circuit that optimally matches the SQUID impedance to the input of a room-temperature FET preamplifier. The SQUID is operated in a flux-locked loop with a dynamic range of +- 3 x 106 (in a 1-Hz bandwidth), a bandwidth of 0 to 2 KHz, and a slewing rate of 2 x 104 phi/sub o/sec-1. A flux noise power spectrum for a SQUID in a superconducting shield at 4.2 K is shown. Above 2 x 10-2 Hz the spectrum is white with an rms value of 10-5 phi/sub o/Hz/sup -1/2/. At lower frequencies the spectrum is approximately 10-10 (1 Hz/f) phi/sub o/2Hz-1, where f is the frequency. Factors contributing to the long term drift of the SQUID are discussed. A drift rate of 2 x 10-5 phi/sub o/h-1 over a 20-h period is achieved by regulating the temperature of the helium bath. A detailed description is given of the coupling of various input coils to the SQUID. The energy resolution of the SQUID with respect to a current in a 24-turn input coil is 7 x 10-30 J Hz-1 in the white noise region. The energy resolution in the l/f noise region and the long term drift performance are better than for any other SQUID

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2010-06-01

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

  11. 77 FR 69426 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Science.gov (United States)

    2012-11-19

    ... United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Specifications and Management Measures... squid and Illex squid were set for 3 years in 2012 (2012-2014) and therefore will not be included in... longfin squid fishery, as well as the butterfish mortality cap to avoid 1-2 week closures at the end of...

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

    Science.gov (United States)

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

    2004-08-01

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

  13. Cross-linking chemistry of squid beak.

    Science.gov (United States)

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

    2010-12-01

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

  14. Cross-linking Chemistry of Squid Beak*

    Science.gov (United States)

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

    2010-01-01

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

  15. Base distance optimization for SQUID gradiometers

    Energy Technology Data Exchange (ETDEWEB)

    Garachtchenko, A. [Applied Materials, Santa Clara, CA (United States); Matlashov, A.; Kraus, R. [Los Alamos National Lab., NM (United States)

    1998-12-31

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

  16. Feasibility of a stationary micro-SQUID

    CERN Document Server

    Berger, Jorge

    2016-01-01

    The standard operation of a dc SQUID leads to oscillatory electric fields that emit electromagnetic radiation and can change the state of the measured sample. A stationary SQUID could be advantageous when back action on the measured sample has to be avoided. We study a superconducting loop that encloses a magnetic flux, connected to a superconducting and to a normal electrode, when a fixed electric current between the electrodes flows through the loop. The considered circuit does not contain Josephson junctions. We find that in a very broad range of parameters the current flow converges to a stationary regime. The potential difference between the electrodes depends on the magnetic flux, so that measuring this voltage would provide information on the enclosed flux. The influence of thermal noise was estimated. The sizes of the voltage and of the power dissipation could be appropriate for the design of a practical fluxmeter. We found narrow ranges of flux at which the voltage varies sharply with the flux.

  17. Application of SQUID to magnetic contaminant detection

    International Nuclear Information System (INIS)

    We have developed a magnetic metallic contaminant detector using a high-temperature superconducting quantum interference device (HTS-SQUID) gradiometer for industrial products such as lithium ion batteries. Finding ultrasmall metallic contaminants is a critical issue for manufacturers producing commercial products such as lithium ion batteries. When contamination occurs, the manufacturer incurs a great loss in recalling the tainted products. We employed a permanent ring magnet for magnetizing the products in order to generate remnant fields only at the ends of the products, thereby reducing their impact in masking the field from a contaminant. For practical applications, the detection width of a sensor must be sufficiently large to identify an inclusion from above the product during inspection. Here, we made a large SQUID gradiometer 8 mm in width and compared its detection width with that of a conventional small sensor 3 mm wide. We found that the effective detection width of the 8 mm sensor was 11.6 mm. It was 1.8 times larger than that of the small sensor. Finally, a test of the system's performance revealed that iron particles as small as 50 μm x 50 μm on the electrode of a lithium ion battery could be detected clearly.

  18. High speed non-latching squid binary ripple counter

    International Nuclear Information System (INIS)

    High speed, single flux quantum (SFQ) binary scalers are important components in superconducting analog-to-digital converters (ADC). This paper reviews the concept for a SQUID ADC and the design of an SFQ binary ripple counter, and reports the simulation of key components, and fabrication and performance of non-latching SQUID scalers and SFQ binary ripple counters. The SQUIDs were fabricated with Nb/Nb2O5/PbIn junctions and interconnected by monolithic superconducting transmission lines and isolation resistors. Each SQUID functioned as a bistable flip-flop with the input connected to the center of the device and the output across one junction. All junctions were critically damped to optimize the pulse response. Operation was verified by observing the dc I-V curves of successive SQUIDs driven by a cw pulse train generated on the same chip. Each SQUID exhibited constant-voltage current steps at 1/2 the voltage of the preceding device as expected from the Josephson voltage-to-frequency relation. Steps were observed only for the same voltage polarity of successive devices and for proper phase bias of the SQUID. Binary frequency division was recorded up to 40GHz for devices designed to operate to 28GHz

  19. Recent Results of a New Microwave SQUID Multiplexer

    Science.gov (United States)

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

    2007-01-01

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

  20. Multistability and self-organization in disordered SQUID metamaterials

    International Nuclear Information System (INIS)

    Planar arrays of magnetoinductively coupled rf SQUIDs (Superconducting QUantum Interference Devices) belong to the emergent class of superconducting metamaterials that encompass the Josephson effect. These SQUID-based metamaterials acquire their electromagnetic properties from the resonant characteristics of their constitutive elements, i.e., the individual rf SQUIDs. In its simplest version, an rf SQUID consists of a superconducting ring interrupted by a Josephson junction. We investigate numerically the response of a two-dimensional rf SQUID metamaterial with respect to the driving frequency of an externally applied alternating magnetic field in the presence of disorder arising from critical current fluctuations of the Josephson elements; in effect, the resonance frequencies of individual SQUIDs are distributed randomly around a mean value. Bistability is observed in the current amplitude–frequency curves both in ordered and disordered SQUID metamaterials; moreover, bistability is favored by disorder through the improvement of synchronization between SQUID oscillators. Relatively weak disorder widens significantly the bistability region by helping the system to self-organize and leads to nearly homogeneous states that change smoothly with varying driving frequency. Also, the total current of the metamaterial is enhanced, compared with that of uncoupled SQUIDs, through the synergetic action of coupling and synchronization. The existence of simultaneously stable states that provide either high or low total current, allows the metamaterial to exhibit different magnetic responses that correspond to different values of the effective magnetic permeability. At low power of the incident field, high current amplitude states exhibit extreme diamagnetic properties corresponding to negative magnetic permeability in a narrow frequency interval. (paper)

  1. An automated and versatile ultra-low temperature SQUID magnetometer

    OpenAIRE

    Morello, A.; Angenent, W. G. J.; Frossati, G.; de Jongh, L.J.

    2004-01-01

    We present the design and construction of a SQUID-based magnetometer for operation down to temperatures T = 10 mK, while retaining the compatibility with the sample holders typically used in commercial SQUID magnetometers. The system is based on a dc-SQUID coupled to a second-order gradiometer. The sample is placed inside the plastic mixing chamber of a dilution refrigerator and is thermalized directly by the 3He flow. The movement though the pickup coils is obtained by lifting the whole dilu...

  2. An automated and versatile ultra-low temperature SQUID magnetometer

    CERN Document Server

    Morello, A; Frossati, G; De Jongh, L J

    2004-01-01

    We present the design and construction of a SQUID-based magnetometer for operation down to temperatures T = 10 mK, while retaining the compatibility with the sample holders typically used in commercial SQUID magnetometers. The system is based on a dc-SQUID coupled to a second-order gradiometer. The sample is placed inside the plastic mixing chamber of a dilution refrigerator and is thermalized directly by the 3He flow. The movement though the pickup coils is obtained by lifting the whole dilution refrigerator insert. A home-developed software provides full automation and an easy user interface.

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

    Science.gov (United States)

    Popov, V. A.

    2016-02-01

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

  4. HTS ion damage Josephson junction technology for SQUID arrays

    International Nuclear Information System (INIS)

    The high temperature superconducting (HTS) Josephson Junction (JJ) ion damage technology we are developing is well suited for making large SQUID arrays. We have studied arrays of similar SQUIDs together with large SQIFs (Superconducting Quantum Interference Filter) with 2000 SQUIDs of different loop areas. Magnetic field sensitivity has been measured in both types of devices as a function of bias current and temperature. The effects of the barrier thickness (from 20 to 80 nm) and JJ length (2 or 5 μm) on characteristics have been investigated.

  5. SQUID-based instrumentation for ultra-low-field MRI

    OpenAIRE

    Zotev, V. S.; Matlashov, A. N.; Volegov, P. L.; Urbaitis, A. V.; Espy, M. A.; Kraus Jr, R. H.

    2007-01-01

    Magnetic resonance imaging at ultra-low fields (ULF MRI) is a promising new imaging method that uses SQUID sensors to measure the spatially encoded precession of pre-polarized nuclear spin populations at a microtesla-range measurement field. In this work, a seven-channel SQUID system designed for simultaneous 3D ULF MRI and magnetoencephalography (MEG) is described. The system includes seven second-order SQUID gradiometers, characterized by magnetic field resolutions of 1.2 - 2.8 fT/rtHz. It ...

  6. High-Tc SQUIDs fabricated by inhibiting ion implantation

    International Nuclear Information System (INIS)

    We have fabricated YBaCuO superconducting quantum interference devices (SQUIDs) using an inhibiting ion implantation method. The devices were patterned by implanting silicon or boron ions through photoresist masks to locally inhibit the conductivity. The implantation was performed at energies of 40-120 keV and doses of 1015-1016 cm-2. The DC SQUIDs consist of step-edge junctions on SrTiO3 substrates. Operational SQUIDs fabricated with this new patterning method were demonstrated at 77 K. Line widths of 2 μm have been achieved and sharp superconducting-normal boundaries were observed. The surface of the patterned device remained planar. (author)

  7. SQUIDs in thermal detectors of weakly interacting particles

    International Nuclear Information System (INIS)

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

  8. The hysteric of SQUID as reactance and the possibility of a phase-sensitive detection of the rf SQUID

    International Nuclear Information System (INIS)

    It is shown theoretically that a switch process in the hysteretic SQUID leads to a phase shift between the tank circuit voltage and the dricing generator current. Considering only a pure switch model the influence of the parametric SQUID inductance will not be taken into account. In the hysteretic mode of the SQUID the tank circuit is not only damped, bus also detuned. On the time average the rf SQUID appears as a reactance. Its amplitude and phase depend on the magnetic field applied to the SQUID. In order to simulate the possibility of phase-sensitive detection the spiral description developed by the authors will be brought up. The practical case of a 30-MHz SQUID was simulated on a digital computer whereby the frequency was varied from the resonance to the - 3 dB bandlimits of the tank circuit. An experiment which detects simultaneously the amplitude of the tank circuit voltage as well as its phase as a function of the magnetic field in the SQUID is described. (orig.)

  9. Realizing and optimizing an atomtronic SQUID

    Science.gov (United States)

    Mathey, Amy C.; Mathey, L.

    2016-05-01

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

  10. rf SQUID system as tunable flux qubit

    International Nuclear Information System (INIS)

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

  11. The Unharmonic dc SQUID Energy Level Splitting

    International Nuclear Information System (INIS)

    A DC SQUID with Josephson junctions characterized by nonsinusoidal current-phase relation is being considered as a basis for a phase qubit. It has been shown that the second and third harmonic components in the current-phase relation are able to provide a double-well potential and the energy level splitting. The threshold condition for the double-well formation has been determined taking into account the impact of both harmonics. The splitting of the ground state energy level has been calculated as a function of the harmonic amplitudes for different ratio s of characteristic Josephson energy EC to the Coulomb energy EQ0. It has been shown that the gap value comes to about 7EQ0 with increase of the ratio s. No external field needed, no bias current required and no circular currents are the major advantages of such a qubit

  12. Vortices in superconducting bulk, films and SQUIDs

    Indian Academy of Sciences (India)

    Ernst Helmut Brandt

    2006-01-01

    The properties of the ideal periodic vortex lattice in bulk superconductors and in films of any thickness can be calculated from Ginzburg-Landau theory by an iteration method using Fourier series. The London theory yields general analytic expressions for the magnetic field and energy of arbitrary arrangements of straight or curved vortex lines. The elasticity of the vortex lattice is highly nonlocal. The magnetic response of superconductors of realistic shapes like thin and thick strips and disks or thin rectangular plates or films, containing pinned vortices, can be computed within continuum theory by solving an integral equation. A useful example is a thin square with a central hole and a radial slit, used as superconducting quantum interference device (SQUID).

  13. Signal and noise characteristics of bi-SQUID

    International Nuclear Information System (INIS)

    We present an improved analytic theory, numerical simulation, and analysis of noise characteristics of a bi-SQUID in comparison with those of a dc SQUID in an open loop configuration. The analytic theory which had been developed earlier, neglecting a pulse component of the difference of the phases of Josephson junctions, is now completed taking into account the pulse component. In the bi-SQUID, the additional Josephson junction introduces another source of fluctuations and changes its transfer function, nonlinear dynamics, and the noise spectrum transformation. Some increase in the reduced-to-input noise at low values of applied magnetic flux comes from the nonlinear flux to phase difference transformation that was introduced in bi-SQUID as a way to linearize its voltage response. (paper)

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

    International Nuclear Information System (INIS)

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

  15. HTS SQUIDs for the nondestructive evaluation of composite structures

    Energy Technology Data Exchange (ETDEWEB)

    Carr, Chris; Graham, David; Macfarlane, John C; Donaldson, Gordon B [Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom)

    2003-12-01

    While LTS and HTS SQUIDs have successfully been applied in the detection of flaws in aircraft grade aluminium structures for well over a decade, interest has recently spread to a type of new material, namely composites. One example, carbon fibre reinforced polymer (CFRP), is increasingly being favoured by the aircraft industry because of its strength to weight ratio and the fact that it is corrosion-resistant. Material and defect characterization using SQUIDs is still at an early stage, but due to expected rapid expansion in the use of such materials, there is ample scope for the application of HTS SQUIDs. Here we have applied HTS SQUID single-layer gradiometers to investigate artificially created defects in CFRP samples.

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

    Science.gov (United States)

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

    2015-05-15

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

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

    Science.gov (United States)

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

    2006-06-01

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

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

    International Nuclear Information System (INIS)

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

  19. Gear Selectivity of a Longfin Squid Bottom Trawl

    Data.gov (United States)

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

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

    Science.gov (United States)

    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.

  1. High transition-temperature SQUID magnetometers and practical applications

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-05-01

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

  2. High transition-temperature SQUID magnetometers and practical applications

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  4. Nb nanoSQUIDs for detection of small spin systems

    International Nuclear Information System (INIS)

    We report on the realization of highly sensitive dc nanoSQUIDs for the investigation of small spin systems in moderate magnetic fields. The Nb SQUIDs are based on normal metal Josephson junctions made of HfTi and patterned by e-beam lithography. We demonstrate stable operation up to B = ± 50 mT without degradation of rms flux noise (SΦ1/2 ≤ 280 nΦ0/√(Hz)). We also present a multifunctional system combining a Nb nanoSQUID and a low-temperature magnetic force microscope (LTMFM) with a Ni nanotube as a scanning tip. This system allows for magnetization measurements of the Ni tube by using both, LTMFM and SQUID readout. Furthermore, the measurement of magnetic flux Φ vs. position of the particle provides an experimental determination of the coupling factor φμ = Φ/μ between SQUID and Ni tube with magnetic moment μ. The results confirm our predictions from numerical simulations, taking into account the SQUID geometry.

  5. Nb nanoSQUIDs for detection of small spin systems

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-07-01

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

  6. [Biochemistry and functional characterization of squid mantle meat (Dosidicus gigas)].

    Science.gov (United States)

    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. PMID:11464670

  7. A scanning SQUID microscope with 200 MHz bandwidth

    International Nuclear Information System (INIS)

    We developed a scanning DC SQUID microscope with novel readout electronics capable of wideband sensing of RF magnetic fields from 50 to 200 MHz and simultaneously providing closed-loop response at kHz frequencies. To overcome the 20 MHz bandwidth limitation of traditional closed-loop SQUIDs, a flux-modulated closed-loop simultaneously locks the SQUID quasi-static flux and flux-biases the SQUID for amplification of the RF flux up to Φ0/4 in amplitude. Demodulating the SQUID voltage with a double lock-in technique yields a signal representative of both the amplitude and phase of the RF flux. This provides 80 dB of a linear dynamic range with a flux noise density of 4 μΦ0 Hz−1/2 at 200 MHz for a Y Ba2Cu3O7 bi-crystal SQUID at 77 K. We describe the electronics’ performance and present images for RF magnetic field of the travelling wave in a coplanar waveguide, the standing wave in an open-circuited microstrip, and a surface mounted device antenna. (paper)

  8. DC and RF Measurements of Serial Bi-SQUID Arrays

    CERN Document Server

    Prokopenko, G V; de Escobar, A Leese; Taylor, B; de Andrade, M C; Berggren, S; Longhini, P; Palacios, A; Nisenoff, M; Fagaly, R L

    2012-01-01

    SQUID arrays are promising candidates for low profile antennas and low noise amplifier applications. We present the integrated circuit designs and results of DC and RF measurements of the wideband serial arrays based on integration of linear bi-SQUID cells forming a Superconducting Quantum Interference Filter (bi-SQUID SQIF). Various configurations of serial arrays designs are described. The measured linearity, power gain, and noise temperature are analyzed and compared. The experimental results are matched to results of mathematical modeling. A serial bi-SQUID SQIF arrays are mounted into a coplanar waveguide (CPW) and symmetrically grounded to corresponding sides of CPW. The RF output comes out from the central common line, which is also used for DC biasing and forms a symmetrical balanced output. The signal and DC flux biasing line is designed as coplanar lines passed in parallel over each bi-SQUID cell in a bidirectional fashion concentrating magnetic flux inside of each cell. Serial bi-SQUID SQIF arrays ...

  9. Readout of TESs and MCCs with SQUID current sensors

    International Nuclear Information System (INIS)

    Transition-Edge Sensors (TESs) and Magnetically Coupled Calorimeters (MCCs) are two categories of low-temperature, low-impedance radiation detectors, that have the potential to significantly improve a variety of photon-sensing applications. For example, TES and MCC detectors and systems are under development to detect single THz photons, to enable the measurement of photon number states at telecom wavelengths with very high quantum efficiency or for high-resolution X-ray and gamma ray spectrometers. Owing to their excellent sensitivity and dynamic performance as well as their compatibility with the low operating temperatures, current sensors based upon Superconducting Quantum Interference Devices (SQUIDs) are ubiquitously used to read out TESs and MCCs. The required SQUID performance in terms of input referred current noise, dynamic range, bandwidth, acceptable power dissipation and potential back-action can vary substantially for different TES or MCC detectors. Consequently, suitable SQUID current sensors need to be adapted to the readout configuration at hand. Ground- and satellite-based astronomy instruments that use thousands of TES pixels set particularly stringent requirements on the detector readout and require SQUID-based multiplexers. This contribution reviews concepts and performance of state-of-the-art SQUID current sensors for single TES and MCC readout as well as SQUID multiplexing techniques.

  10. Noise analysis of DC SQUIDs with damped superconducting flux transformers

    International Nuclear Information System (INIS)

    An analysis was performed of intrinsic noise for high-Tc DC SQUID with superconducting flux transformer (FT) containing resistive elements. For a SQUID with a loop inductance of about 40 pH we observed voltage swings of ∼55 μV and a flux noise of ∼4 μΦ0/√Hz at 77 K. Inductive coupling of an 8-mm multilayer superconducting FT to the SQUID increased voltage swings to ∼70 μV due to effective reduction of the SQUID loop inductance. This also increased the flux noise to ∼6μΦ0/√Hz, corresponding to a field resolution of ∼18 fT/√Hz at 77 K with a white noise spectrum down to frequency ∼10 Hz. The main sources of white flux noise were the Nyquist noise in the Josephson junctions and the FT, as well as the suppression of the DC SQUID voltage swings caused by parasitic capacitance between the FT and the SQUID. An ultra-low-ohmic resistor with resistance value between the flux-creep-induced resistances of superconductors (below ∼0.1 nΩ) and resistances of conventional resistors (above ∼0.1 mΩ) was developed. An RL-circuit based high-pass filter (HPF) with time constant ∼7 sec was realized and integrated in the superconducting FT. The contribution of the HPF to the noise of the sensors was measured and compared with calculated values.

  11. An investigation of pinch welds using HTS SQUIDs

    International Nuclear Information System (INIS)

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

  12. An investigation of pinch welds using HTS SQUIDs

    Science.gov (United States)

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

    2006-05-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-03-01

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

  14. Nuclear magnetic resonance experiments with dc SQUID amplifiers

    International Nuclear Information System (INIS)

    The development and fabrication of dc SQUIDs (Superconducting QUantum Interference Devices) with Nb/Al2O3/Nb Josephson junctions is described. A theory of the dc SQUID as a radio-frequency amplifier is presented, with an optimization strategy that accounts for the loading and noise contributions of the postamplifier and maximizes the signal-to-noise ratio of the total system. The high sensitivity of the dc SQUID is extended to high field NMR. A dc SQUID is used as a tuned radio-frequency amplifier to detect pulsed nuclear magnetic resonance at 32 MHz from a metal film in a 3.5 Tesla static field. A total system noise temperature of 11 K has been achieved, at a bath temperature of 4.2 K. The minimum number of nuclear Bohr magnetons observable from a free precession signal after a single pulse is about 2 x 1017 in a bandwidth of 25 kHz. In a separate experiment, a dc SQUID is used as a rf amplifier in a NQR experiment to observe a new resonance response mechanism. The net electric polarization of a NaClO3 crystal due to the precessing electric quadrupole moments of the Cl nuclei is detected at 30 MHz. The sensitivity of NMR and NQR spectrometers using dc SQUID amplifiers is compared to the sensitivity of spectrometers using conventional rf amplifiers. A SQUID-based spectrometer has a voltage sensitivity which is comparable to the best achieved by a FET-based spectrometer, at these temperatures and operating frequencies

  15. SQUID detected NMR in microtesla magnetic fields

    Science.gov (United States)

    Matlachov, Andrei N.; Volegov, Petr L.; Espy, Michelle A.; George, John S.; Kraus, Robert H.

    2004-09-01

    We have built an NMR system that employs a superconducting quantum interference device (SQUID) detector and operates in measurement fields of 2-25 μT. The system uses a pre-polarizing field from 4 to 30 mT generated by simple room-temperature wire-wound coils that are turned off during measurements. The instrument has an open geometry with samples located outside the cryostat at room-temperature. This removes constraints on sample size and allows us to obtain signals from living tissue. We have obtained 1H NMR spectra from a variety of samples including water, mineral oil, and a live frog. We also acquired gradient encoded free induction decay (FID) data from a water-plastic phantom in the μT regime, from which simple projection images were reconstructed. NMR signals from samples inside metallic containers have also been acquired. This is possible because the penetration skin depth is much greater at the low operating frequencies of this system than for conventional systems. Advantages to ultra-low field NMR measurements include lower susceptibility artifacts caused by high strength polarizing and measurement fields, and negligible line width broadening due to measurement field inhomogeneity, reducing the burden of producing highly homogeneous fields.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-06-08

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

  17. Gamma-ray irradiation tests of High-Tc SQUID

    International Nuclear Information System (INIS)

    Gamma-ray irradiation tests of High-Tc SQUIDs were carried out to examine their workability in nuclear reactor environments. The SQUIDs were made of a HoBa2Cu3O7-x superconductive thin film on SrTiO3 substrates. Some were encapsulated in separate cases of glass-fiber-rein-forced epoxy resin. Gamma-ray irradiation was performed with a Co-60 gamma-ray source. Irradiation dose rates were (8.1 to 12.2) x 103 Gy/h (i.e., (1.0 to 1.5) x 106 R/h), and the maximum absorption dose was about 10.4 MGy. During and after irradiation, noises of SQUIDs were measured with a power spectrum analyzer. Changes in modulation voltage were also investigated. No gamma-ray induced noise was observed during irradiation. The noise level and modulation voltage did not change until a total irradiation dose of about 3 MGy, and after that it decreased slightly. We concluded that the tested high-Tc SQUIDs are very resistant to gamma-ray irradiation, and thus the application of high-Tc SQUIDs in inspection of reactor components seems promising. (author)

  18. Practical application High-Tc SQUID beam current monitor

    International Nuclear Information System (INIS)

    To measure the DC current of heavy-ion beams non-destructively at high resolution, we have developed a high critical temperature (HTc) superconducting quantum interference device (SQUID) beam current monitor for use in the radioactive isotope beam factory (RIBF) at RIKEN. Unlike at other existing facilities, a low vibration, pulse-tube refrigerator cools the HTc fabrications including the SQUID in such a way that the size of the system is reduced and the running costs are lowered. Last year, the magnetic shielding system has been greatly reinforced. The new strong magnetic shielding system can attenuate the external magnetic noise to 10-10. Aiming at its practical use for acceleration operation, the prototype HTc SQUID monitor was disassembled, exchange the improved parts and re-assembled. Beginning this year, we have installed the HTc SQUID monitor in the beam transport line in the RIBF. Here we report the present details of the developed HTc SQUID monitor system and the results of the beam measurement. (author)

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

    Science.gov (United States)

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

    1997-03-01

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

  20. Eddy current nondestructive material evaluation based on HTS SQUIDs

    Science.gov (United States)

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

    1997-08-01

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

  1. Calibration of SQUID vector magnetometers in full tensor gradiometry systems

    Science.gov (United States)

    Schiffler, M.; Queitsch, M.; Stolz, R.; Chwala, A.; Krech, W.; Meyer, H.-G.; Kukowski, N.

    2014-08-01

    Measurement of magnetic vector or tensor quantities, namely of field or field gradient, delivers more details of the underlying geological setting in geomagnetic prospection than a scalar measurement of a single component or of the scalar total magnetic intensity. Currently, highest measurement resolutions are achievable with superconducting quantum interference device (SQUID)-based systems. Due to technological limitations, it is necessary to suppress the parasitic magnetic field response from the SQUID gradiometer signals, which are a superposition of one tensor component and all three orthogonal magnetic field components. This in turn requires an accurate estimation of the local magnetic field. Such a measurement can itself be achieved via three additional orthogonal SQUID reference magnetometers. It is the calibration of such a SQUID reference vector magnetometer system that is the subject of this paper. A number of vector magnetometer calibration methods are described in the literature. We present two methods that we have implemented and compared, for their suitability of rapid data processing and integration into a full tensor magnetic gradiometry, SQUID-based, system. We conclude that the calibration routines must necessarily model fabrication misalignments, field offset and scale factors, and include comparison with a reference magnetic field. In order to enable fast processing on site, the software must be able to function as a stand-alone toolbox.

  2. Characterization of the Vibrio fischeri Fatty Acid Chemoreceptors, VfcB and VfcB2.

    Science.gov (United States)

    Nikolakakis, K; Monfils, K; Moriano-Gutierrez, S; Brennan, C A; Ruby, E G

    2016-01-01

    Bacteria use a wide variety of methyl-accepting chemotaxis proteins (MCPs) to mediate their attraction to or repulsion from different chemical signals in their environment. The bioluminescent marine bacterium Vibrio fischeri is the monospecific symbiont of the Hawaiian bobtail squid, Euprymna scolopes, and encodes a large repertoire of MCPs that are hypothesized to be used during different parts of its complex, multistage lifestyle. Here, we report the initial characterization of two such MCPs from V. fischeri that are responsible for mediating migration toward short- and medium-chain aliphatic (or fatty) acids. These receptors appear to be distributed among only members of the family Vibrionaceae and are likely descended from a receptor that has been lost by the majority of the members of this family. While chemotaxis greatly enhances the efficiency of host colonization by V. fischeri, fatty acids do not appear to be used as a chemical cue during this stage of the symbiosis. This study presents an example of straight-chain fatty acid chemoattraction and contributes to the growing body of characterized MCP-ligand interactions. PMID:26567312

  3. 77 FR 74159 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Science.gov (United States)

    2012-12-13

    ... Mackerel, Squid, and Butterfish (MSB) Fishery Management Plan (FMP) (75 FR 11441, March 11, 2010) as a... United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Framework Adjustment 7 AGENCY... on the longfin squid fishery from a catch cap to a discard cap in Framework Adjustment 7 to...

  4. DC-SQUID with enhanced magnetic field sensitivity

    International Nuclear Information System (INIS)

    When designing a thinfilm DC-SQUID for insertion into a multichannel sensor circuit for biomagnetic applications, a minimum number of fabrication steps (e.g. mask layers) and simple thinfilm patterns are desirable. For measurements in a well shielded environment like the Berlin magnetically shielded room /1/ this requirement is met advantageously when flux transformers are omitted and the SQUID-loops themselves serve as magnetometer pick-up coils. In this case the DC-SQUIDs are designed for optimized magnetic field sensitivity instead of flux response. In this paper a single layer all-Nb thinfilm design that displays I-V- characteristics without resonant structures and the merits of a resistively shunted double loop circuit are presented

  5. NMR/MRI with hyperpolarized gas and high Tc SQUID

    Science.gov (United States)

    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.

  6. Chimeras in locally coupled SQUIDs: Lions, goats and snakes

    CERN Document Server

    Hizanidis, J; Tsironis, G P

    2016-01-01

    We report on the emergence of robust multi-clustered chimera states in a dissipative-driven system of symmetrically and locally coupled identical SQUID oscillators. The "snake-like" resonance curve of the single SQUID (Superconducting QUantum Interference Device) is the key to the formation of the chimera states and is responsible for the extreme multistability exhibited by the coupled system that leads to attractor crowding at the geometrical resonance frequency. Until now, chimera states were mostly believed to exist for nonlocal coupling. Our findings provide theoretical evidence that nearest neighbor interactions is indeed capable of supporting such states in a wide parameter range. SQUID metamaterials are the subject of intense experimental investigations and we are highly confident that the complex dynamics demonstrated in this manuscript can be confirmed in the laboratory.

  7. Improved Readout Scheme for SQUID-Based Thermometry

    Science.gov (United States)

    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.

  8. Polarization rotation by an rf-SQUID metasurface

    CERN Document Server

    Caputo, J -G; Maimistov, A I

    2015-01-01

    We study the transmission and reflection of a plane electromagnetic wave through a two dimensional array of rf-SQUIDs. The basic equations describing the amplitudes of the magnetic field and current in the split-ring resonators are developed. These yield in the linear approximation the reflection and transmission coefficients. The polarization of the reflected wave is independent of the frequency of the incident wave and of its polarization; it is defined only by the orientation of the split-ring. The reflection and transmission coefficients have a strong resonance that is determined by the parameters of the rf-SQUID; its strength depends essentially on the incident angle.

  9. SQUID-based Resonant Detection of Axion Dark Matter

    CERN Document Server

    Popov, Vladimir

    2014-01-01

    A new method for searching for Dark Matter axions is proposed. It is shown that a two-contact SQUID can detect oscillating magnetic perturbations induced by the axions in a strong inhomogeneous magnetic field. A resonant signal is a steplike response in the SQUID current-voltage characteristic at a voltage corresponding to the axion mass with a height depending on the axion energy density near the Earth. The proposed experimental technique appears to be sensitive to the axions with masses $m_a\\lesssim 10^{-4}$ eV, which is well-motivated by current researches both in cosmology and in particle physics.

  10. Squid detected NMR and MRI at ultralow fields

    Science.gov (United States)

    Clarke, John; Pines, Alexander; McDermott, Robert F.; Trabesinger, Andreas H.

    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.

  11. A Simple Quantum Integro-Differential Solver (SQuIDS)

    CERN Document Server

    Delgado, Carlos Alberto Arguelles; Weaver, Christopher N

    2014-01-01

    Simple Quantum Integro-Differential Solver (SQuIDS) is a C++ code designed to solve semi-analytically the evolution of a set of density matrices and scalar functions. This is done efficiently by expressing all operators in an SU(N) basis. SQuIDS provides a base class from which users can derive new classes to include new non-trivial terms from the right hand sides of density matrix equations. The code was designed in the context of solving neutrino oscillation problems, but can be applied to any problem that involves solving the quantum evolution of a collection of particles with Hilbert space of dimension up to six.

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

    Energy Technology Data Exchange (ETDEWEB)

    Mariyappa, N., E-mail: mariyappa@igcar.gov.in [Condensed Matter Physics Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India); Parasakthi, C.; Sengottuvel, S.; Gireesan, K.; Patel, Rajesh; Janawadkar, M.P.; Sundar, C.S.; Radhakrishnan, T.S. [Condensed Matter Physics Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India)

    2012-07-15

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

  13. Low-noise FET amplifier for dc SQUID

    International Nuclear Information System (INIS)

    We report on the design, characterization, and operation of a low-noise FET-input differential amplifier, which is used as second stage for a dc SQUID in the electronic instrumentation of the gravitational wave detector of the Rome group at CERN. The 3-dB bandwidth of the amplifier is from 10 kHz to 1.5 MHz. At the SQUID modulation frequency of 70 kHz the voltage noise is 0.5 nV/(Hz)1/2, the current noise is 35 fA/(Hz)1/2

  14. High-T{sub c} SQUID microscope with sample chamber

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Saburo; Yamazaki, Osamu; Shimizu, Ryoji; Saito, Yusuke [Ecological Engineering, Toyohashi University of Technology, Hibarigaoka Tempaku-cho Toyohashi Aichi 441-8580 (Japan)

    1999-11-01

    We have designed and constructed a high-T{sub c} superconducting quantum interference device (SQUID) microscope with a sample chamber isolated by a shutter. It can image magnetic distributions of samples at both room temperature and 77 K. According to our scheme, the separation of the sample from the SQUID can be less than a few micrometres, in principle. We have successfully imaged a trapped flux in a YBa{sub 2}Cu{sub 3}O{sub 7-y} thin-film ring at 77 K and a printout of a laser printer at room temperature. (author)

  15. Scanning high-Tc SQUID imaging system for magnetocardiography

    International Nuclear Information System (INIS)

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

  16. An Economical Magnetocardiogram System Based on High-Tc SQUIDs

    Institute of Scientific and Technical Information of China (English)

    LI Zhuo; ZHU Xue-Min; ZHANG Li-Hua; HUANG Xu-Guang; REN Yu-Feng; CHEN Geng-Hua; YANG Qian-Sheng; FENG Ji

    2006-01-01

    @@ An economical magnetocardiogram (MCG) system is built in our laboratory. It mainly consists of a MCG data acquisition stage equipped with two high-Tc superconducting quantum interference device (SQUID) magnetometers,a data processing stage with digital filtering and a one-layer μ-metal magnetically shielded room in conjunction with a high-Tc SQUID based active compensation. Experimental results show that a noise level of pico-tesla in MCG profiles, which is necessary for clinical applications, may be achieved with the system. Moreover, stable and convenient operations of the system are demonstrated with simulating MCG measurements.

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

    Science.gov (United States)

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

    2016-05-01

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

  18. SQUID magnetometer with YBa2Cu3O7 grain boundary step contacts

    International Nuclear Information System (INIS)

    The report describes the assembly and characterisation of SQUID magnetometers consisting of a SQUID and a coupled superconducting flux antenna. Two concepts for coupling of the antenna were implemented: First, a directly coupled magnetometer in which the flux antenna is produced parallel to the SQUID, i.e. only a single YBCO layer is required; secondly, a flip-chip magnetometer where the flux antenna is produced on a different substrate and is coupled to the SQUID inductively. The SQUIDs were produced on the basis of grain boundary step contacts

  19. Development of low-power dc-SQUIDs for future X-ray satellite missions

    International Nuclear Information System (INIS)

    Requirements and implementations of low-power dc-SQUIDs used with TES microcalorimeters for one of future X-ray satellite missions, Diffuse Intergalactic Oxygen Surveyor (DIOS), are discussed. The current DIOS design as to a refrigerator limits the maximum power dissipation of a single SQUID to 20 nW or less, which is far below a SQUID we have been using. The SQUID also has to be capable of high-frequency inputs as it is AC-biased to multiplex TES signals. We designed and developed low-power dc-SQUIDs usable on the orbit, as well as a multi-input current-summing SQUID chip ready for frequency-division multiplexing. We finally tested radiation tolerance of the developed SQUIDs using cobalt-60 radioisotope. (author)

  20. Development of nano and micro SQUIDs based on Al tunnel junctions

    International Nuclear Information System (INIS)

    Superconducting quantum interference devices (SQUIDs) with nano (micro)-meter dimensions are called nano (micro)-SQUIDs. The high sensitivity for flux and position of nano (micro)-SQUIDs can be applied to detect local magnetic fields induced by vortices and the magnetization of mesoscopic superconductors. Nano-SQUIDs based on carbon-nanotube junctions and niobium weak junctions are well known. However, such nano-SQUIDs are not suitable for large-scale integrated circuits and mass production. Therefore, we employ a combination of lithography using the Niemeyer-Dolan technique and the inductively coupled plasma reactive-ion etching technique to fabricate nano-SQUIDs. Here, we report the fabrication of nano (micro)-SQUIDs based on superconducting aluminum tunnel junctions and their application for vortex formation into mesoscopic chiral superconducting Sr2RuO4[1-3

  1. Towards automated remote SQUID stations for geomagnetic measurements

    Directory of Open Access Journals (Sweden)

    Lochner Emile

    2014-01-01

    Full Text Available SQUID magnetometers for geomagnetic research can only be used optimally if they are moved away from man-made interference. This leads to several problems related to infrastructure. This article briefly discusses current research involving issues with site selection, liquid nitrogen monitoring and transfer, and the use of Helmholtz coils for zero-field cooling and orientation.

  2. Review of Magneto cardiography Technology based on SQUID

    International Nuclear Information System (INIS)

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

  3. Vampire squid: detritivores in the oxygen minimum zone.

    Science.gov (United States)

    Hoving, Hendrik J T; Robison, Bruce H

    2012-11-22

    Vampire squid (Vampyroteuthis infernalis) are considered phylogenetic relics with cephalopod features of both octopods and squids. They lack feeding tentacles, but in addition to their eight arms, they have two retractile filaments, the exact functions of which have puzzled scientists for years. We present the results of investigations on the feeding ecology and behaviour of Vampyroteuthis, which include extensive in situ, deep-sea video recordings from MBARI's remotely operated vehicles (ROVs), laboratory feeding experiments, diet studies and morphological examinations of the retractile filaments, the arm suckers and cirri. Vampire squid were found to feed on detrital matter of various sizes, from small particles to larger marine aggregates. Ingested items included the remains of gelatinous zooplankton, discarded larvacean houses, crustacean remains, diatoms and faecal pellets. Both ROV observations and laboratory experiments led to the conclusion that vampire squid use their retractile filaments for the capture of food, supporting the hypothesis that the filaments are homologous to cephalopod arms. Vampyroteuthis' feeding behaviour is unlike any other cephalopod, and reveals a unique adaptation that allows these animals to spend most of their life at depths where oxygen concentrations are very low, but where predators are few and typical cephalopod food is scarce. PMID:23015627

  4. A unique advantage for giant eyes in giant squid.

    Science.gov (United States)

    Nilsson, Dan-Eric; Warrant, Eric J; Johnsen, Sönke; Hanlon, Roger; Shashar, Nadav

    2012-04-24

    Giant and colossal deep-sea squid (Architeuthis and Mesonychoteuthis) have the largest eyes in the animal kingdom [1, 2], but there is no explanation for why they would need eyes that are nearly three times the diameter of those of any other extant animal. Here we develop a theory for visual detection in pelagic habitats, which predicts that such giant eyes are unlikely to evolve for detecting mates or prey at long distance but are instead uniquely suited for detecting very large predators, such as sperm whales. We also provide photographic documentation of an eyeball of about 27 cm with a 9 cm pupil in a giant squid, and we predict that, below 600 m depth, it would allow detection of sperm whales at distances exceeding 120 m. With this long range of vision, giant squid get an early warning of approaching sperm whales. Because the sonar range of sperm whales exceeds 120 m [3-5], we hypothesize that a well-prepared and powerful evasive response to hunting sperm whales may have driven the evolution of huge dimensions in both eyes and bodies of giant and colossal squid. Our theory also provides insights into the vision of Mesozoic ichthyosaurs with unusually large eyes. PMID:22425154

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

    International Nuclear Information System (INIS)

    A simple method is described which reduces those systematic errors of a superconducting quantum interference device (SQUID) magnetometer that arise from possible radial displacements of the sample in the second-order gradiometer superconducting pickup coil. By rotating the sample rod (and hence the sample) around its axis into a position where the best fit is obtained to the output voltage of the SQUID as the sample is moved through the pickup coil, the accuracy of measuring magnetic moments can be increased significantly. In the cases of an examined Co1.9Fe1.1Si Heusler alloy, pure iron and nickel samples, the accuracy could be increased over the value given in the specification of the device. The suggested method is only meaningful if the measurement uncertainty is dominated by systematic errors – radial displacement in particular – and not by instrumental or environmental noise. - Highlights: • A simple method is described which reduces systematic errors of a SQUID. • The errors arise from a radial displacement of the sample in the gradiometer coil. • The procedure is to rotate the sample rod (with the sample) around its axis. • The best fit to the SQUID voltage has to be attained moving the sample through the coil. • The accuracy of measuring magnetic moment can be increased significantly

  6. SQUID and magneto-optic investigations of flux turbulence

    DEFF Research Database (Denmark)

    Koblischka, M.R.; Johansen, T.H.; Baziljevich, M.; Murakami, M.; Wolf, T.

    Instabilities of the critical state ("turbulence") are observed in various high-T-c, single crystals by means of magneto-optic (MO) imaging. Using the same samples as in the MO investigations, we observe for the first time characteristic steps in the magnetic moment measured by means of a SQUID...

  7. A 128 Multiplexing Factor Time-Domain SQUID Multiplexer

    Science.gov (United States)

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

    2016-01-01

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

  8. HTS dc SQUID based rf amplifier: development concept

    DEFF Research Database (Denmark)

    Prokopenko, G.V.; Shitov, S.V.; Borisenko, I.V.; Mygind, Jesper

    We present a concept of a rf amplifier based on a directly coupled dc SQUID with bicrystal junctions, which have high saturation power and can be used with SIS mixers or possibly for satellite and cellular phone communications. A novel input resonant circuit is proposed using single layer of HTS...

  9. A YBCO RF-SQUID magnetometer and its applications

    Science.gov (United States)

    Luwei, Zhou; Jingwu, Qiu; Xienfeng, Zhang; Zhiming, Tank; Yongjia, Qian

    1990-01-01

    An applicable RF-superconducting quantum interference detector (SQUID) magnetometer was made using a bulk sintered yttrium barium copper oxide (YBCO). The temperature range of the magnetometer is 77 to 300 K and the field range 0 to 0.1T. At 77 K, the equivalent flux noise of the SQUID is 5 x 10 to minus 4 power theta sub o/square root of Hz at the frequency range of 20 to 200 Hz. The experiments show that the SQUID noise at low-frequency end is mainly from 1/f noise. A coil test shows that the magnetic moment sensitivity delta m is 10 to the minus 6th power emu. The RF-SQUID is shielded in a YBCO cylinder with a shielding ability B sub in/B sub ex of about 10 to the minus 6th power when external dc magnetic field is about a few Oe. The magnetometer is successfully used in characterizing superconducting thin films.

  10. Review of Magneto cardiography Technology based on SQUID

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-04-15

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

  11. A high-resolution, SQUID-based vibrating coil susceptometer

    International Nuclear Information System (INIS)

    A superconducting quantum interference device (SQUID) plays an important role in the development of ultrasensitive electric and magnetic measurement systems. SQUID instrumentation offers diversified applications with its ability to make measurements where other methodologies could not be applied. A high sensitivity magnetic measurement technique to measure the magnetic susceptibility of extremely small volume samples using a SQUID vibrating coil magnetometer (SVCM) has been developed. In this setup, position differentiating detection (PDD) of magnetic flux from the sample has been coupled with the SQUID magnetometer. The sensitivity of the setup depends on the vibrating amplitude of the pick-up coil. The pick-up coil of the SVCM has been steadily vibrated with a maximum amplitude of 75 µm close to the sample at the resonant frequency using bimorph piezoelectric bender type actuators. An equivalent circuit model for the piezoelectric actuator has been constructed, and its resonance frequency has also been cross-checked by simulation software. The vibration of actuators for a wide range of temperatures (4.2 K–300 K) has been controlled by a negative feedback circuit. The detailed design, construction and performance of the SVCM have been described

  12. High-Tc SQUID magnetometer system with active cancellation

    Science.gov (United States)

    Kuriki, S.; Oyama, H.; Hayashi, A.; Washio, T.; Fujita, M.; Hirata, Y.

    2002-05-01

    Recent developments of high-Tc SQUIDs have enabled high sensitivity magnetometers to be used in wide range of places, such as laboratory and outdoor fields. At the early stage of developing multichannel system for measurement of magnetocardiogram (MCG) in clinical application, we have fabricated a single channel high-Tc SQUID magnetometer system. The system includes a direct-coupled SQUID with slot structure, a simple magnetically shielded room (MSR), and some active compensation electronics for the purpose of reducing various environmental field noises. A novel active noise cancellation was made by using a combination of a normal conducting detection coil that was horizontally wound in the middle height of the MSR, and two compensation coils that were wound at the top and bottom of the MSR. In addition, adaptive noise cancellation was supplemented by means of adaptive digital filter that was implemented in a digital signal processor. A total noise field attenuation of 50-60 dB was attained at 0.5-100 Hz. Low noise signals from the human heart were measured with a high-Tc SQUID in the noise reduced space in the MSR.

  13. HTS dc SQUID based rf amplifier: development concept

    DEFF Research Database (Denmark)

    Prokopenko, G.V.; Shitov, S.V.; Borisenko, I.V.;

    2002-01-01

    We present a concept of a rf amplifier based on a directly coupled dc SQUID with bicrystal junctions, which have high saturation power and can be used with SIS mixers or possibly for satellite and cellular phone communications. A novel input resonant circuit is proposed using single layer of HTS...

  14. SQUID-based instrumentation for ultra-low-field MRI

    CERN Document Server

    Zotev, V S; Matlashov, A N; Urbaitis, A V; Kraus, R H

    2007-01-01

    Magnetic resonance imaging at ultra-low fields (ULF MRI) is a promising new imaging method that uses SQUID sensors to measure the spatially encoded precession of pre-polarized nuclear spin populations at a microtesla-range measurement field. In this work, design and performance of a seven-channel SQUID system for simultaneous 3D ULF MRI and MEG are described. The system consists of seven axial second-order SQUID gradiometers, characterized by magnetic field resolutions of 1.2 - 2.8 fT/rtHz. It also includes five sets of coils for 3D Fourier imaging with pre-polarization. Design components used for rapid switching of the pre-polarizing field and for protecting the SQUIDs from the pre-polarizing pulses are discussed. The system's performance is demonstrated by multi-channel 3D images of a preserved sheep brain acquired at 46 microtesla measurement field with 2.5 mm x 2.5 mm x 5 mm imaging resolution. The ULF MRI images exhibit greater contrast than images of the same brain obtained using conventional high-field...

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

    International Nuclear Information System (INIS)

    We have measured the spectral density of the 1/f voltage noise in current-biased resistively shunted Josephson tunnel junctions and dc SQUIDs. A theory in which fluctuations in the temperature give rise to fluctuations in the critical current and hence in the voltage predicts the magnitude of the noise quite accurately for junctions with areas of about 2 x 104 μm2, but significantly overestimates the noise for junctions with areas of about 6 μm2. DC SQUIDs fabricated from these two types of junctions exhibit substantially more 1/f voltage noise than would be predicted from a model in which the noise arises from critical current fluctuations in the junctions. This result was confirmed by an experiment involving two different bias current and flux modulation schemes, which demonstrated that the predominant 1/f voltage noise arises not from critical current fluctuations, but from some unknown source that can be regarded as an apparent 1/f flux noise. Measurements on five different configurations of dc SQUIDs fabricated with thin-film tunnel junctions and with widely varying areas, inductances, and junction capacitances show that the spectral density of the 1/f equivalent flux noise is roughtly constant, within a factor of three of (10-10/f)phi20Hz-1. It is emphasized that 1/f flux noise may not be the predominant source of 1/f noise in SQUIDS fabricated with other technologies

  16. Spatial Fourier transform method for evaluating SQUID gradiometers

    International Nuclear Information System (INIS)

    A simple method of measuring the spatial transfer function of a gradiometer, consisting of a flux transformer coupled to a SQUID, is presented and it is compared with theoretical predictions. Based, on this approach, a new method of reporting a gradiometer's performance is proposed; the rejection factor is expressed in decibels obtained directly from the transfer function plot

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

    Energy Technology Data Exchange (ETDEWEB)

    Kiss, L.F., E-mail: kissl@szfki.hu; Kaptás, D.; Balogh, J.

    2014-11-15

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

  18. Optimization of dc SQUID voltmeter and magnetometer circuits

    International Nuclear Information System (INIS)

    We calculate the signal-to-noise ratio in a dc SQUID system as a function of source impedance, taking into account the effects of current and voltage noise sources in the SQUID. The optimization of both tuned and untuned volmeters and magnetometers is discussed and typical sensitivities are predicted using calculated noise spectra. The calculations are based on an ideal symmetric dc SQUID with β=2LI0/Phi0=1 and moderate noise rounding (GAMMA=2k/sub B/T/I0Phi0=0.05), where Phi0 is the flux quantum, T is the temperature, L is the SQUID inductance, and I0 is the critical current of each junction. The optimum noise temperatures of tuned and untuned voltmeters are found to be 2.8(ωL/R) T and 8(ωL/R) T (1+1.5α2 +0.7α4)/sup 1/2//α2 respectively, where ω/2π is the signal frequency, assumed to be much less than the Josephson frequency, and α is the coupling coefficient between the SQUID and its input coil. It is found that tuned and untuned magnetometers can be characterized by optimum effective signal energies given by (16k/sub B/TLB/α2R)[1+1l5α2 +0.7α2)/sup 1/2/+0.75α2] and 2k/sub B/T/sub i/R/sub i/B/ω2L/sub p/ respectively, where B is the bandwidth, R/sub i/ is the resistance representing the losses in the tuned circuit at temperture T/sub i/, and L/sub p/ is the inductance of the pickup coil

  19. A study of 3He films using SQUID NMR

    International Nuclear Information System (INIS)

    Confinement of superfluid 3He to a geometry of order the coherence length is predicted to produce interesting size effects and modify the superfluid phase diagram. This thesis describes the development of an experiment to measure these effects using NMR as a probe of the spin dynamics. A pulsed NMR spectrometer was developed with a low Tc SQUID as the first stage amplifier. The sample was located in a receiver coil that formed part of a tuned circuit with the SQUID input coil. The first spectrometer was operated in an open-loop configuration but was later converted to use feedback to stabilize the SQUID gain. This later version used a DC SQUID with APF operating in flux-locked loop using the Direct Offset Integration Technique. The noise was limited by the Johnson noise in the tuned circuit in tests down to 1.5 K and the estimated noise temperature was ∼100 mK. NMR signals were observed at ∼1 MHz from low-density 3He samples adsorbed on a Mylar substrate which were in reasonable agreement with the estimated signal sizes. A cell was constructed with a highly polished silver substrate to study a 100 nm thick 3He film adsorbed on an area of ∼1 cm2. This was mounted on a newly installed demagnetization cryostat. A dipper probe was constructed for the SQUID spectrometer which demonstrated an overall coupled energy sensitivity of 327 h before being mounted on the cryostat. NMR signals were observed from samples equivalent to films of thickness 100, 400, and 800 nm on the substrate surface at temperatures ranging from 60 mK down to 415 μK. No superfluid transition was detected. With each sample a time dependence of the signal was observed which may be attributable to a thermomechanical effect in normal liquid 3He. Based on the measured signals, it is predicted that ∼1016 spins should be detectable in a single-shot. (author)

  20. Development of robust HTS-SQUID for non-destructive inspection system in unshielded environment

    International Nuclear Information System (INIS)

    Cross-shaped YBa2Cu3O7−x (YBCO) film was overlapped on directly-coupled multi-pickup-coil HTS-dc-SQUID magnetometer in flip-chip configuration as a superconducting shield, and the characterestics of the SQUID were examined in DC and AC magnetic fields. We created slots in the YBCO film and pickup-coil of HTS-SQUID magnetometer for suppression of flux trapping. In low magnetic field environment, we measured the characteristics of the SQUID without and with HTS film. The most of the parameters were same with and without the HTS films, while S1/2φ with the HTS film was a bit smaller than that of the bare SQUID. In the DC field, Ic of the HTS-SQUID covered with the HTS film did not change until a DC field over 140 μT was applied to the SQUID, while the bare SQUID's Ic decreased with the increase of the applied DC field. In the AC fields at 10 MHz, the SQUID with the HTS film showed degradation of the parameters such as Vpp and S12φ at lower field amplitude than the bare SQUID.

  1. First-order Wire-wound SQUID Gradiometer System Having Compact Superconductive Connection Structure between SQUID and Pickup Coil

    International Nuclear Information System (INIS)

    In order to have a superconductive connection between the wire-wound pickup coil and input coil, typically Nb terminal blocks with screw holes are used. Since this connection structure occupies large volume, large stray pickup area can be generated which can pickup external noise fields. Thus, SQUID and connection block are shielded inside a superconducting tube, and this SQUID module is located at some distance from the distal coil of the gradiometer to minimize the distortion or imbalance of uniform background field due to the superconducting module. To operate this conventional SQUID module, we need a higher liquid He level, resulting in shorter refill interval. To make the fabrication of gradiometers simpler and refill interval longer, we developed a novel method of connecting the pickup coil into the input coil. Gradiometer coil wound of 0.125-mm diameter NbTi wires were glued close to the input coil pads of SQUID. The superconductive connection was made using an ultrasonic bonding of annealed 0.025-mm diameter Nb wires, bonded directly on the surface of NbTi wires where insulation layer was stripped out. The reliability of the superconductive bonding was good enough to sustain several thermal cycling. The stray pickup area due to this connection structure is about 0.1 mm2 , much smaller than the typical stray pickup area using the conventional screw block method. By using this compact connection structure, the position of the SQUID sensor is only about 20-30 mm from the distal coil of the gradiometer. Based on this compact module, we fabricated a magnetocardiography system having 61 first-order axial gradiometers, and measured MCG signals. The gradiometers have a coil diameter of 20 mm, and the baseline is 70 mm. The 61 axial gradiometer bobbins were distributed in a hexagonal lattice structure with a sensor interval of 26 mm, measuring dBz/dz component of magnetocardiography signals.

  2. First-order Wire-wound SQUID Gradiometer System Having Compact Superconductive Connection Structure between SQUID and Pickup Coil

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-10-15

    In order to have a superconductive connection between the wire-wound pickup coil and input coil, typically Nb terminal blocks with screw holes are used. Since this connection structure occupies large volume, large stray pickup area can be generated which can pickup external noise fields. Thus, SQUID and connection block are shielded inside a superconducting tube, and this SQUID module is located at some distance from the distal coil of the gradiometer to minimize the distortion or imbalance of uniform background field due to the superconducting module. To operate this conventional SQUID module, we need a higher liquid He level, resulting in shorter refill interval. To make the fabrication of gradiometers simpler and refill interval longer, we developed a novel method of connecting the pickup coil into the input coil. Gradiometer coil wound of 0.125-mm diameter NbTi wires were glued close to the input coil pads of SQUID. The superconductive connection was made using an ultrasonic bonding of annealed 0.025-mm diameter Nb wires, bonded directly on the surface of NbTi wires where insulation layer was stripped out. The reliability of the superconductive bonding was good enough to sustain several thermal cycling. The stray pickup area due to this connection structure is about 0.1 mm{sup 2} , much smaller than the typical stray pickup area using the conventional screw block method. By using this compact connection structure, the position of the SQUID sensor is only about 20-30 mm from the distal coil of the gradiometer. Based on this compact module, we fabricated a magnetocardiography system having 61 first-order axial gradiometers, and measured MCG signals. The gradiometers have a coil diameter of 20 mm, and the baseline is 70 mm. The 61 axial gradiometer bobbins were distributed in a hexagonal lattice structure with a sensor interval of 26 mm, measuring dB{sub z}/dz component of magnetocardiography signals.

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  5. Magneto-cardiogram measurement using a high-Tc SQUID magnetometer

    International Nuclear Information System (INIS)

    We made Superconducting Quantum Interference Devices (SQUIDs) coupled with large pick-up loops (directly coupled SQUIDs) by using single-layer YBCO thin films on SrTiO3 bicrystal substrates. The I-V characteristics of the SQUIDs showed Resistively Shunted Junction type (RSJ-type) behavior, and the measured IcRn values were in the 100∼300 μV range. The rms field resolution of a directly coupled SQUID measured in liquid nitrogen was 0.9 pT/Hz at 1 Hz and 0.1 pT/Hz at 1 kHz. Using this directly coupled SQUID, we have developed a SQUID magnetometer system operating in liquid nitroge, and we used that system in a magnetically shielded environment to measure biomagnetic signals from human heart

  6. Planar SQUID magnetometer integrated with bootstrap circuitry under different bias modes

    International Nuclear Information System (INIS)

    A planar superconducting quantum interference device (SQUID) magnetometer consisting of a parallel gradiometer SQUID with integrated input coils connected to an on-chip pickup loop was designed and fabricated in conventional niobium technology. SQUID bootstrap circuitry (SBC) incorporating suitable current and voltage feedbacks was also integrated into the design. For a SQUID inductance of Ls = 350 pH and a chip size of 5 × 5 mm2, the field resolution of the voltage-biased SQUID magnetometer reached −1/2 with the bootstrap circuit and an ordinary preamplifier. We also observed that the effective McCumber parameter βc of the junctions is influenced by the bias mode. Indeed, when the nominal junction βc was larger than unity, our SQUID magnetometer operated stably in the voltage bias mode. The device exhibited low noise even without SBC. (paper)

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

    International Nuclear Information System (INIS)

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

  8. nanoSQUID operation using kinetic rather than magnetic induction

    Science.gov (United States)

    McCaughan, Adam N.; Zhao, Qingyuan; Berggren, Karl K.

    2016-06-01

    We report on a method of nanoSQUID modulation which uses kinetic inductance rather than magnetic inductance to manip-ulate the internal fluxoid state. We produced modulation using injected current rather than an applied magnetic field. Using this injected current, we were able to observe the triangle-wave shaped modulation of the device critical current which was periodic according to the London fluxoid quantization condition. The measurement results also confirmed that the fluxoid state inside a superconducting loop can be manipulated using primarily kinetic inductance. By using primarily kinetic inductance rather than magnetic inductance, the size of the coupling inductor was reduced by a factor of 10. As a result, this approach may provide a means to reduce the size of SQUID-based superconducting electronics. Additionally, this method provides a convenient way to perform kinetic inductance characterizations of superconducting thin films.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-10-15

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

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

    Science.gov (United States)

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

    2015-10-01

    We report on the development of a three-axis absolute vector magnetometer suited for mobile operation in the Earth's magnetic field. It is based on low critical temperature dc superconducting quantum interference devices (LTS dc SQUIDs) with sub-micrometer sized cross-type Josephson junctions and exhibits a white noise level of about 10 fT/Hz1/2. The width of superconducting strip lines is restricted to less than 6 μm in order to avoid flux trapping during cool-down in magnetically unshielded environment. The long-term stability of the flux-to-voltage transfer coefficients of the SQUID electronics is investigated in detail and a method is presented to significantly increase their reproducibility. We further demonstrate the long-term operation of the setup in a magnetic field varying by about 200 μT amplitude without the need for recalibration.

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

    International Nuclear Information System (INIS)

    We report on the development of a three-axis absolute vector magnetometer suited for mobile operation in the Earth’s magnetic field. It is based on low critical temperature dc superconducting quantum interference devices (LTS dc SQUIDs) with sub-micrometer sized cross-type Josephson junctions and exhibits a white noise level of about 10 fT/Hz1/2. The width of superconducting strip lines is restricted to less than 6 μm in order to avoid flux trapping during cool-down in magnetically unshielded environment. The long-term stability of the flux-to-voltage transfer coefficients of the SQUID electronics is investigated in detail and a method is presented to significantly increase their reproducibility. We further demonstrate the long-term operation of the setup in a magnetic field varying by about 200 μT amplitude without the need for recalibration

  12. Scanning SQUID microscopy in a cryogen-free refrigerator

    Science.gov (United States)

    Schaefer, Brian T.; Low, David; Prawiroatmodjo, Guenevere E. D. K.; Nangoi, J. Kevin; Kim, Jihoon; Nowack, Katja C.

    With helium prices rising and supply becoming increasingly uncertain, it has become attractive to use dry cryostats with cryocoolers rather than liquid helium to reach low temperatures. However, a cryocooler introduces vibrations at the sample stage, making scanning probe experiments more challenging. Here, we report our progress on a superconducting quantum interference device (SQUID) microscope implemented for the first time in a compact, cryogen-free 5 K system. Our microscope is designed to reach submicron spatial resolution and a flux sensitivity of approximately 1 μΦ0 /√{ Hz} , where Φ0 is the magnetic flux quantum. To enable height feedback while approaching and scanning samples, we mount the SQUID on a quartz tuning fork. Our system promises to meet the capabilities of similar systems implemented in helium cryostats.

  13. SQUID Magnetometry for Cancer Screening a Feasibility Study

    CERN Document Server

    Kenning, G G; Zotev, V S; Moslemi, A; Wilson, S; Hawel, L; Byus, C; Kovach, J S

    2003-01-01

    The recent demonstration that nanoparticles associated with various biological molecules and pharmacological agents can be administered systemically to humans, without toxicity from the particles, has opened a new era in the targeting of such particles to specific tissues in the body for the imaging and therapy of disease. The majority of particles used for this purpose contain iron and are detected in the body by magnetic resonance imaging. We believe a superconducting quantum interference device (SQUID) could provide quantitative and spatial information relevant to localization of superparamagnetic nanoparticles directed to a specific cell target in vivo. We envision a scanning system consisting of a DC induction field, a transport device, and an array of planar first order gradiometer coils coupled to DC SQUID amplifiers. We performed a set of computer simulations using experimentally determined values for concentrations of paramagnetic particles achievable in specific tissues of the mouse in vivo and conc...

  14. Multi-tone response of Nonlinear rf-SQUID metamaterials

    Science.gov (United States)

    Zhang, Daimeng; Trepanier, Melissa; Mukhanov, Oleg; Antonsen, Thomas; Ott, Edward; Anlage, Steven

    We study the multi-tone response over a broad microwave frequency range of a nonlinear superconducting meta-atom and a metamaterial composed of Radio Frequency Superconducting QUantum Interference Devices (rf-SQUIDs). Nonlinearity in the SQUID metamaterial gives rise to large-range tunable resonance via dc/rf magnetic field and temperature, it also results in signal mixing through intermodulation distortion (IMD). Our metamaterial responds to multi-frequency signals and generates strong higher order intermodulation signals in a certain range of applied rf power. However, our meta-atom and metamaterial show a reduced third-order IMD generation around the resonance, which is unusual for typical nonlinear systems. The numerical simulation predicts the same IMD gap feature as in experiment. A comprehensive analytical model is applied to explain the phenomena, and methods to enhance, or reduce, intermodulation levels are explored. This work is supported by the NSF-GOALI and OISE programs through Grant # ECCS-1158644, and CNAM.

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

    International Nuclear Information System (INIS)

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

  16. nSQUID arrays as conveyers of quantum information

    International Nuclear Information System (INIS)

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

  17. nSQUID arrays as conveyers of quantum information

    Science.gov (United States)

    Deng, Qiang; Averin, D. V.

    2014-12-01

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

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

    Science.gov (United States)

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

    2014-11-01

    A simple method is described which reduces those systematic errors of a superconducting quantum interference device (SQUID) magnetometer that arise from possible radial displacements of the sample in the second-order gradiometer superconducting pickup coil. By rotating the sample rod (and hence the sample) around its axis into a position where the best fit is obtained to the output voltage of the SQUID as the sample is moved through the pickup coil, the accuracy of measuring magnetic moments can be increased significantly. In the cases of an examined Co1.9Fe1.1Si Heusler alloy, pure iron and nickel samples, the accuracy could be increased over the value given in the specification of the device. The suggested method is only meaningful if the measurement uncertainty is dominated by systematic errors - radial displacement in particular - and not by instrumental or environmental noise.

  19. Squid rhodopsin and GTP-binding protein crossreact with vertebrate photoreceptor enzymes.

    OpenAIRE

    Saibil, H R; Michel-Villaz, M

    1984-01-01

    The activation of photoreceptor GTP-binding protein by rhodopsin was studied in squid photoreceptors and in crossreactions between the squid and bovine proteins. Turbidity changes were observed in the far-red after photoexcitation of rhodopsin with brief flashes and were used to probe interactions between photoreceptor membrane suspensions and soluble protein extracts. Our findings are squid photoreceptors contain a GTP-binding protein detectable by light- and GTP-sensitive turbidity changes ...

  20. In vitro antioxidant, antimutagenic and antiproliferative activities of collagen hydrolysates of jumbo squid (Dosidicus gigas) byproducts

    OpenAIRE

    Guadalupe Miroslava Suárez-Jiménez; Rosario Maribel Robles-Sánches; Glória Yépiz-Plascencia; Armando Burgos-Hernández; Josafat Marina Ezquerra-Brauer

    2015-01-01

    AbstractHydrolysates from two different jumbo squid byproducts (fins and arms), produced by trypsin and protease type XIV were compared on the basis of their antioxidant (DPPH and ABTS radical scavenging assays), antimutagenic (Ames test) and antiproliferative (Transformation cell proliferation in M12.C3F6 murine cells) activities. Jumbo squid arms had higher content of collagen than fins, and their hydrolysates had the highest antioxidant activity. Also, jumbo squid arm-derived collagen hydr...

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

    Science.gov (United States)

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

    2008-10-01

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

  2. Comprehensive Model of Jumbo Squid Dosidicus gigas Trophic Ecology in the Northern Humboldt Current System

    OpenAIRE

    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 evi...

  3. Modified SQUID Operator Equation for a Single-Qubit Structure Coupled to a Quantum Resonator

    International Nuclear Information System (INIS)

    Role of self-inductance in superconducting quantum interference device (SQUID) charge qubit is considered. It is found that when an SQUID charge qubit is coupled to a quantum LC resonator, the SQUID voltage operator equation is modified in accompanying with the modification of operator Faraday equation describing the inductance. It is shown that when the extra energy is applied to the junction, the mean phase will be squeezed according to a damping factor

  4. Measurement of forward and reverse signal transfer coefficients for an rf-biased SQUID

    International Nuclear Information System (INIS)

    Comprehensive measurements of the parameters characterizing an rf-biased SQUID as a linear twoport are described. The behavior of the device corresponds in detail to the predictions of a recently published model of SQUID operation and is unexpectedly similar to that of a conventional reactive parametric amplifier. The measurements have been used to make the first reliable predictions of the noise temperature and optimum source impedance of an rf-biased SQUID

  5. Polarization rotation by an rf-SQUID metasurface

    OpenAIRE

    Caputo, J. -G.; Gabitov, I.; Maimistov, A. I.

    2015-01-01

    We study the transmission and reflection of a plane electromagnetic wave through a two dimensional array of rf-SQUIDs. The basic equations describing the amplitudes of the magnetic field and current in the split-ring resonators are developed. These yield in the linear approximation the reflection and transmission coefficients. The polarization of the reflected wave is independent of the frequency of the incident wave and of its polarization; it is defined only by the orientation of the split-...

  6. Frontiers in Squid Reproduction: Prospecting for New Antibiotics

    OpenAIRE

    Epel, David

    2002-01-01

    Many strains of disease-causing bacteria have become resistant to antibiotics, leading those in the medical profession to search for new sources of drugs. Although most antibiotics have been derived from terrestrial life, it is the marine world that may provide the pharmaceutical industry with the next generation of medicines. The biochemistries of seemingly simple marine organisms such as blue-green algae, sponges and squid are inspiring new ideas for drug development.

  7. Cosmological flux noise and measured noise power spectra in SQUIDs

    OpenAIRE

    Beck, Christian

    2014-01-01

    The understanding of the origin of $1/f$ magnetic flux noise commonly observed in superconducting devices such as SQUIDS and $q$-bits 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 in...

  8. The Transition from Stiff to Compliant Materials in Squid Beaks

    OpenAIRE

    Miserez, Ali; Schneberk, Todd; Sun, Chengjun; Zok, Frank W.; Waite, J. Herbert

    2008-01-01

    The beak of the Humboldt squid Dosidicus gigas represents one of the hardest and stiffest wholly organic materials known. As it is deeply embedded within the soft buccal envelope, the manner in which impact forces are transmitted between beak and envelope is a matter of considerable scientific interest. Here, we show that the hydrated beak exhibits a large stiffness gradient, spanning two orders of magnitude from the tip to the base. This gradient is correlated with a chemical gradient involv...

  9. Absolute calibration and beam background of the Squid Polarimeter

    International Nuclear Information System (INIS)

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

  10. Critical state analysis using continuous reading SQUID magnetometer

    Czech Academy of Sciences Publication Activity Database

    Janů, Zdeněk; Švindrych, Zdeněk; Youssef, A.; Baničová, L.

    Rijeka : Intech, 2011 - (Luiz, A.), s. 261-276 ISBN 978-953-307-151-0 R&D Projects: GA ČR GA202/08/0722 Institutional research plan: CEZ:AV0Z10100520 Keywords : thin superconducting films * critical state * critical current density Subject RIV: BM - Solid Matter Physics ; Magnetism http://www.intechopen.com/articles/show/title/critical-state-analysis-using-continuous-reading- squid -magnetometer

  11. Dynamic Characteristics of S-band DC SQUID Amplifier

    DEFF Research Database (Denmark)

    Prokopenko, G. V.; Shitov, S. V.; Koshelets, I. L. L. V. P.; Mygind, Jesper

    2003-01-01

    A low-noise rf amplifier based on a de SQUID (SQA) has been tested in the frequency range 3.0-4.6 GHz in the open-loop configuration. The following parameters have been measured for the single-stage balanced type SQA at 4.0 GHz: gain (12 +/- 1) dB, 3 dB bandwidth of 500 MHz and noise temperature (1...

  12. Elimination of flux-transformer crosstalk in multichannel SQUID magnetometers

    OpenAIRE

    Brake, ter, O.; Fleuren, F.H.; Ulfman, J.A.; Flokstra, J.

    1986-01-01

    Multichannel SQUID magnetometers are being developed for signal-field mapping in biomagnetic experiments. A problem that becomes more serious as the number of channels is increased is the crosstalk caused by the mutual inductances between the individual sensing coils. A simple and effective method for eliminating this crosstalk is presented in this Paper. The method is based on a rearrangement of the feedback loops which causes the flux-transformer circuits to become currentless. The feasibil...

  13. Elimination of flux-transformer crosstalk in multichannel SQUID magnetometers

    Science.gov (United States)

    ter Brake, H. J. M.; Fleuren, F. H.; Ulfrnan, J. A.; Flokstra, J.

    Multichannel SQUID magnetometers are being developed for signal-field mapping in biomagnetic experiments. A problem that becomes more serious as the number of channels is increased is the crosstalk caused by the mutual inductances between the individual sensing coils. A simple and effective method for eliminating this crosstalk is presented in this Paper. The method is based on a rearrangement of the feedback loops which causes the flux-transformer circuits to become currentless. The feasibility of the method is verified experimentally.

  14. A survey of calibration procedures for SQUID gradiometers

    CERN Document Server

    Ornelas, P H; Barbosa, C H; Lima, E A; Ribeiro, P C

    2003-01-01

    The accuracy of three distinct experimental procedures for calibrating axial SQUID gradiometers has been compared, for the same gradiometer design and experimental setup. Each procedure employs a different field source, and a nonlinear least-squares optimization is used to fit the measured voltage to the theoretical field, thus determining Tesla/Volt calibration factors. We also studied the effect of noise and gradiometer imbalance on the accuracy of each procedure.

  15. Superconducting bolometer array with SQUID readout for submillimetre wavelength detection

    International Nuclear Information System (INIS)

    We have tested a fully microfabricated superconducting bolometer array for astrophysical observations at submillimetre wavelengths. The system is cooled by a 3He sorption refrigerator operating in a pumped 4He cryostat. The transition edge bolometer uses a bilayer of molybdenum and a gold-palladium alloy with a transition temperature of around 500 mK as the thermometer. The bolometer is voltage biased, and the current is measured by a superconducting quantum interference device (SQUID) ammeter

  16. Simple differential thermometer using a thermocouple with a SQUID detector

    International Nuclear Information System (INIS)

    Details of design and construction of a simple and rugged thermocouple differential thermometer are presented. Gold + 0.03 at. % iron wire is used, with niobium leads connected to a SQUID. It is demonstrated that at 1 K the response time is about 15 ms and that the temperature sensitivity of 10-7 K with a 10 Hz filter is Johnson-noise limited. 3 references

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

    International Nuclear Information System (INIS)

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

  18. SQUID microscope read-out on a Josephson junction array

    International Nuclear Information System (INIS)

    LTC Josephson junction arrays (JJA) have recently gained interest as a model for the study of magnetization in superconductor materials. The presence of paramagnetic Meissner effect in such devices when field-cooled makes them an excellent candidate to discriminate between the different explanations given for such phenomenon. On the other hand, the understanding of the JJA physics is not simple due to the interplay between the non-linear behaviour of Josephson devices and the mutual induction effects in large JJA. The use of a SQUID microscope (SSM) to catch the magnetic image of the array is a distinctive feature of the experiment. So a study of SQUID read-out based on the actual JJA magnetic behaviour is needed in order to have a correct picture of what is going on. In this paper, using a simple way to reconstruct the complex array far-field viewed by the SQUID, we study how the flux read-out is dependent on array resolution, distance, tilting and noise for the typical situations in which arrays are found. (author)

  19. Fabrication and characterization of shunted μ-SQUID

    International Nuclear Information System (INIS)

    In order to eliminate hysteresis, we have fabricated and characterized niobium based shunted micron size superconducting quantum interference devices (μ-SQUIDs). We find a wide temperature range where these μ-SQUIDs are non-hysteretic in nature and show a very good Ic vs. B oscillations in hysteretic regime and V vs. B oscillations in non-hysteretic regime. Here we report the characteristics of a shunted- μ-SQUID (Wf38LS72D5). In this device we have achieved a large voltage modulation, in non-hysteretic regime, at various temperatures including such as 1.1 mV at 6.62 K with a transfer function VΦ = 7.2mV/Φ0. The figures within the original article PDF file, as supplied to AIP Publishing, were affected by a PDF-processing error. Consequently, the article re-flowed and pagination increased from 3 to 4 pages. This article was updated on 14 May 2014 to correct the PDF-processing error, with the scientific content remaining unchanged. Readers are advised that the replacement article PDF file contains an additional blank page to preserve the original pagination

  20. Tunable Anomalous Supercurrent in a topological tri-junction SQUID

    Science.gov (United States)

    Kurter, C.; Finck, A. D. K.; Ghaemi, P.; Hor, Y. S.; van Harlingen, D. J.

    2014-03-01

    There has been intense interest in realizing Majorana fermions (MFs) in solid-state systems. Circuits of Josephson junctions (JJs) made of closely spaced s-wave superconductors on 3D topological insulators have been proposed to host zero energy Andreev bound states (ABSs) that act like MFs. Here, we present signatures of an anomalous supercurrent carried by topologically non-trivial low energy ABSs in a Nb/Bi2Se3/Nb tri-junction SQUID where two of the three superconducting leads are connected by a loop. An electrostatic top gate allows strong modulation of the supercurrent despite a high bulk contribution to the normal state conductance. In response to a magnetic field threading flux within the superconducting loop, we find unconventional SQUID oscillations enclosed by an envelope associated with a clear diffraction pattern, indicating spatially uniform and symmetric JJs. At a critical gate voltage, when the trivial 2DEG at the surface is nearly depleted, we observe a sharp drop in the critical current, signaling a topological phase transition in which the nature of the supercurrent-carrying states is transformed. This transition is accompanied by qualitative changes in the SQUID oscillations, magnetic diffraction pattern, and temperature dependence of the critical current. We acknowledge funding from Microsoft Station-Q.

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

    International Nuclear Information System (INIS)

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

  2. SQUID array for magnetic inspection of prestressed concrete bridges

    Science.gov (United States)

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

    2002-03-01

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

  3. Cosmological flux noise and measured noise power spectra in SQUIDs.

    Science.gov (United States)

    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

  4. Cosmological flux noise and measured noise power spectra in SQUIDs

    Science.gov (United States)

    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

  5. A planar second-order DC SQUID gradiometer.

    Science.gov (United States)

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

    1991-01-01

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

  6. Magnetic flux in a mesoscopic SQUID controlled by nonclassical electromagnetic fields

    Science.gov (United States)

    Dajka, Jerzy; Łuczka, Jerzy

    2009-11-01

    We analyze SQUID coupled to a nonclassical electromagnetic field (NEM) and show that properties of the SQUID can be manipulated by a choice of a state of NEM. In particular, energy or fluctuations of magnetic flux threading the loop of the SQUID can be resolved into separate lines for each photon number state of one-mode NEM. The impact of two-mode NEM prepared in entangled Bell states is discussed. The findings suggest an experimental method of detection of photon states: the SQUID response is dependent on the number of photons in one-mode NEM and on the Bell states of a two-mode NEM.

  7. Tagging studies on the jumbo squid (Dosidicus gigas) in the Gulf of California, Mexico

    OpenAIRE

    Markaida, Unai; Rosenthal, Joshua J. C.; Gilly, William F

    2005-01-01

    Dosidicus gigas, the only species in the genus Dosidicus, is commonly known as the jumbo squid, jumbo flying squid (FAO, see Roper et al., 1984), or Humboldt squid. It is the largest ommastrephid squid and is endemic to the Eastern Pacific, ranging from northern California to southern Chile and to 140oW at the equator (Nesis, 1983; Nigmatullin, et al., 2001). During the last two decades it has become an extremely important fisheries resource in the Gulf of California (Ehrhardt et al., 1983; M...

  8. Three-qubit quantum-gate operation with an SQUID in a cavity

    International Nuclear Information System (INIS)

    We propose a method of realizing a three-qubit quantum gate with a superconducting quantum interference device (SQUID) in a cavity. In this proposal, the gate operation involves the SQUID ground-states and the Fock states of cavity modes b and ĉ. The two field-modes act as the controlling qubits, and the two SQUID states form the target qubit. Since only the metastable lower levels are involved in the gate operation, the gate is not affected by the SQUID decay rates. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  9. Tuning an rf-SQUID flux qubit system's potential with magnetic flux bias

    International Nuclear Information System (INIS)

    At an extremely low temperature of 20 mK, we measured the loop current in a tunable rf superconducting quantum interference device (SQUID) with a dc-SQUID. By adjusting the magnetic flux applied to the rf-SQUID loop (Φf) and the small dc-SQUID (Φfcjj), respectively, the potential shape of the system can be fully controlled in situ. Variation in the transition step and overlap size in the switching current with a barrier flux bias are analyzed, from which we can obtain some relevant device parameters and build a model to explain the experimental phenomenon

  10. 78 FR 3401 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Science.gov (United States)

    2013-01-16

    ...; Atlantic Mackerel, Squid, and Butterfish Fisheries; Scoping Process; Mid-Atlantic Fishery Management... support for an amendment (Amendment 16) to the Fishery Management Plan (FMP) for Atlantic Mackerel,...

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

    Science.gov (United States)

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

    2013-10-01

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

  12. SQUID detected NMR and NQR. Superconducting Quantum Interference Device.

    Science.gov (United States)

    Augustine, M P; TonThat, D M; Clarke, J

    1998-03-01

    The dc Superconducting QUantum Interference Device (SQUID) is a sensitive detector of magnetic flux, with a typical flux noise of the order 1 muphi0 Hz(-1/2) at liquid helium temperatures. Here phi0 = h/2e is the flux quantum. In our NMR or NQR spectrometer, a niobium wire coil wrapped around the sample is coupled to a thin film superconducting coil deposited on the SQUID to form a flux transformer. With this untuned input circuit the SQUID measures the flux, rather than the rate of change of flux, and thus retains its high sensitivity down to arbitrarily low frequencies. This feature is exploited in a cw spectrometer that monitors the change in the static magnetization of a sample induced by radio frequency irradiation. Examples of this technique are the detection of NQR in 27Al in sapphire and 11B in boron nitride, and a level crossing technique to enhance the signal of 14N in peptides. Research is now focused on a SQUID-based spectrometer for pulsed NQR and NMR, which has a bandwidth of 0-5 MHz. This spectrometer is used with spin-echo techniques to measure the NQR longitudinal and transverse relaxation times of 14N in NH4ClO4, 63+/-6 ms and 22+/-2 ms, respectively. With the aid of two-frequency pulses to excite the 359 kHz and 714 kHz resonances in ruby simultaneously, it is possible to obtain a two-dimensional NQR spectrum. As a third example, the pulsed spectrometer is used to study NMR spectrum of 129Xe after polariza-tion with optically pumped Rb. The NMR line can be detected at frequencies as low as 200 Hz. At fields below about 2 mT the longitudinal relaxation time saturates at about 2000 s. Two recent experiments in other laboratories have extended these pulsed NMR techniques to higher temperatures and smaller samples. In the first, images were obtained of mineral oil floating on water at room temperature. In the second, a SQUID configured as a thin film gradiometer was used to detect NMR in a 50 microm particle of 195Pt at 6 mT and 4.2 K. PMID:9650797

  13. FORMED SEMI-FINISHED PRODUCTS FROM SQUID FORCEMEAT. INVESTIGATION OF THE FUNCTIONAL AND TECHNOLOGICAL PROPERTIES OF FORCEMEAT MIXTURE

    Directory of Open Access Journals (Sweden)

    Ivchenkova E. N.

    2014-09-01

    Full Text Available The influence of addition of boiled forcemeat of a squid to raw forcemeat on functional and technological properties of forcemeat is investigated. The formulation of forcemeat for formed semi-finished products of squid is presented. Periods of storage of formed semi-finished products of squid are substantiated

  14. The computer-aided system for the high resolution SQUID-magnetometer

    International Nuclear Information System (INIS)

    The described computer-aided system for the high resolution SQUID-magnetometer permits one to regulate the thermostat temperature, vary the working magnetic field, change the sample position and allow acquisition and processing of signal from a SQUID. A brief description of electronics and the principal program algorithms is proposed. 7 refs.; 6 figs

  15. 77 FR 67305 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Science.gov (United States)

    2012-11-09

    ... specifications (77 FR 16472; March 21, 2012). The total allowable level of foreign fishing (TALFF) for butterfish... United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Specifications and Management Measures... butterfish fishery, which is managed as part of the Atlantic Mackerel, Squid, and Butterfish...

  16. 76 FR 39313 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Science.gov (United States)

    2011-07-06

    ... butterfish is 495 mt (76 FR 8306, February 14, 2011). Section 648.22 requires NMFS to close the directed... Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Closure of the Directed... under the Atlantic Mackerel, Squid, and Butterfish Fishery Management Plan (FMP). The procedures...

  17. 77 FR 22678 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Science.gov (United States)

    2012-04-17

    ... percent of the quota (8,888 mt) (77 FR 16472, March 21, 2012). The regulations also require 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...

  18. 75 FR 51683 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Science.gov (United States)

    2010-08-23

    ... FR 5537, February 3, 2010). Section 648.22 requires NMFS to close the directed butterfish fishery in... United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Closure of the Directed Butterfish..., Squid, and Butterfish Fishery Management Plan (FMP). The procedures for setting the annual...

  19. 77 FR 40527 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Science.gov (United States)

    2012-07-10

    ... percent of the quota (8,888 mt) (77 FR 16472, March 21, 2012). Due to an underharvest of quota in... Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Closure of the 2012 Trimester 2 Directed Longfin Squid Fishery AGENCY: National Marine Fisheries Service (NMFS), National Oceanic...

  20. A YBCO RF-squid variable temperature susceptometer and its applications

    Science.gov (United States)

    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.

  1. 77 FR 23635 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Science.gov (United States)

    2012-04-20

    ..., 2011 (77 FR 16472). This action established catch levels for the 2012 fishing year for mackerel and... United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Specifications and Management Measures... regulatory text in the final rule for 2012 Specifications for the Atlantic Mackerel, Squid, and...

  2. 75 FR 32745 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Science.gov (United States)

    2010-06-09

    ... meeting dates in a separate Federal Register notice published on May 27, 2010 (75 FR 29725). If the...; Atlantic Mackerel, Squid, and Butterfish Fisheries; Scoping Process AGENCY: National Marine Fisheries...) for Atlantic Mackerel, Squid, and Butterfish (MSB) and to prepare an EIS to analyze the impacts of...

  3. 76 FR 74724 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Science.gov (United States)

    2011-12-01

    ... November 7, 2011 (76 FR 68642). Details regarding the measures in Amendment 11 are in the final rule and... United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Amendment 11 AGENCY: National Marine... implementing Amendment 11 to the Atlantic Mackerel, Squid, and Butterfish (MSB) Fishery Management Plan...

  4. 75 FR 37739 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Science.gov (United States)

    2010-06-30

    ... Butterfish Fisheries in the Federal Register on February 3, 2010 (75 FR 5537). The final rule modified... United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Adjustment to the Loligo Trimester 2... Fishing Year (FY) Trimester 2 and 3 Loligo squid quotas. This action complies with the 2010...

  5. 77 FR 58507 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Science.gov (United States)

    2012-09-21

    ...-9135. SUPPLEMENTARY INFORMATION: Background Amendment 11 to the MSB FMP (76 FR 68642, November 7, 2011... United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Framework Adjustment 5 AGENCY... Adjustment 5 to the Atlantic Mackerel, Squid, and Butterfish Fishery Management Plan (MSB FMP), which...

  6. 75 FR 1024 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Science.gov (United States)

    2010-01-08

    ..., 2003 (68 FR 27516), NMFS published, at the request of the Council, an ANPR indicating that the Council... United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Control Date for Loligo and Illex Squid AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric...

  7. 76 FR 51272 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Science.gov (United States)

    2011-08-18

    ... Loligo was set at 3,384 mt (76 FR 8306, February 14, 2011). Due to an under harvest of the Trimester 1... Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Closure of the 2011 Trimester 2 Directed Loligo Squid Fishery AGENCY: National Marine Fisheries Service (NMFS), National Oceanic...

  8. 76 FR 66260 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Science.gov (United States)

    2011-10-26

    ...), to allow the use of jigging gear to target longfin squid if the longfin squid fishery is closed due... measures (e.g., gear and/or possession restrictions) needed for the efficient management of the fishery... finalized regulations implementing the Omnibus Amendment (76 FR 60606, September 29, 2011),...

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

    Directory of Open Access Journals (Sweden)

    Matladi Thabang

    2014-01-01

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

  10. Temperature dependence of the effective sensing area of high-T{sub c} dc SQUIDs

    Energy Technology Data Exchange (ETDEWEB)

    Brake, H.J.M. ter; Aarnink, W.A.M.; Bosch, P.J. van den; Hilgenkamp, J.W.M.; Flokstra, J.; Rogalla, H. [Low Temperature Division, Faculty of Applied Physics, University of Twente, Enschede (Netherlands)

    1997-07-01

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

  11. Multiplexing of Hot-Electron Nanobolometers Using Microwave SQUIDs

    Science.gov (United States)

    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.

  12. Multiplexing of Hot-Electron Nanobolometers Using Microwave SQUIDs

    Science.gov (United States)

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

    2009-12-01

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

  13. Observation of sine modulated Bessel behavior in microwave biased SQUIDs

    International Nuclear Information System (INIS)

    The amplitudes of the signal lobes (Bessel Maxima) observed in several types of thin film SQUIDs excited at 9.2 GHz exhibit pronounced periodic intensity modulation. This behavior is consistent with the simplified flux entry model proposed by Mercereau in the limit of tau approximately T, where T is the shortest time between successive flux entry into loop and tau is the flux passage time. From the results, tau was deduced to be approximately 1012 seconds for both proximity effect and narrow constriction devices

  14. A compact very low noise dc-SQUID magnetometer

    International Nuclear Information System (INIS)

    We have designed and fabricated a very low noise integrated dc Superconducting QUantum Interference Device (SQUID) magnetometer on a 4x4 mm2 chip. The white flux noise at 1 kHz is 6x10-7Φ0/√Hz. This corresponds to a flux density noise of 3.4 fT/√Hz and a coupled energy resolution of 32 h. The 1/f noise corner frequency is 10 Hz and the 1/f flux noise at 1 Hz is 2x10-6Φ0/√Hz. (orig.)

  15. Sensitivity and spatial resolution of square loop SQUID magnetometers

    International Nuclear Information System (INIS)

    We calculate the flux threading the pick-up coil of a square SQUID magnetometer in the presence of a current dipole source. The result reproduces that of a circle coil magnetometer calculated by Wikswo [J.P. Wikswo, AIP Conf. Proc. 44 (1978) 145] with only small differences. However it has a simpler form so that it is possible to derive from it closed form expressions for the current dipole sensitivity and the spatial resolution. The results are useful to assess the overall performance of the device and allow the comparison of magnetometers with different detection coil size

  16. Electromagnetic Field Scattering on rf-SQUID Based Metasurfaces

    Directory of Open Access Journals (Sweden)

    Сaputo J.G

    2015-01-01

    Full Text Available Electromagnetic field scattering on a 2D array of rf-SQUIDs is considered. We show that the scattering changes for large amplitudes of the incident electromagnetic wave; above a critical amplitude, two different refraction states occur (bistability. In particular, for these two states, the transmitted wave polarization and angle of refraction are different. One could then switch the direction of propagation of the electromagnetic wave and its polarization with a “thin film”, whose thickness is much smaller than the wavelength.

  17. Moderately shielded high-T{sub c} SQUID system for rat MCG

    Energy Technology Data Exchange (ETDEWEB)

    Bechstein, S; Drung, D; Schurig, Th [Physikalisch-Technische Bundesanstalt (PTB), Abbestr. 2-12, 10587 Berlin (Germany); Kim, I-S [Korea Research Institute of Standards and Science (KRISS), Daejeon 305-340 (Korea, Republic of); Novikov, I, E-mail: sylke.bechstein@ptb.d [Novosibirsk State Technical University, K. Marx Avenue 20, Novosibirsk 630092 (Russian Federation)

    2010-06-01

    Recently, we have developed a 5-channel high-T{sub c} SQUID system with one signal channel intended for rat magnetocardiography (MCG) in moderately shielded or 'quiet' real environment. This system is an adapted version of a human MCG system which has been improved with respect to user-friendliness and stability. A dewar with a cold-warm distance of 7 mm and a refill cycle time of up to one week is utilized. The implemented high-T{sub c} SQUIDs are single-layer devices with grain boundary junctions fabricated at KRISS with laser ablation on 10 mm x 10 mm STO substrates. In order to cancel environmental magnetic noise, three of the five SQUIDs are arranged to build an axial software first-order or second-order gradiometer with a base line of 35 mm. The other two SQUIDs are used for balancing. To overcome previous system instabilities, we have implemented an Earth field compensation for each SQUID. For this, the SQUIDs were mounted in capsules containing integrated field compensation coils. The three Earth field components are measured with an additional triaxial fluxgate, and compensated at the SQUID locations using the low-noise current source of the SQUID readout electronics. This way, the SQUIDs can be cooled and operated in a low residual field that improves system stability and reduces low-frequency SQUID noise. It is even possible to slowly move the dewar in the Earth field (dynamic field compensation). Different noise cancellation procedures were optimized and compared employing a periodic signal source.

  18. Analysis of a dc SQUID readout scheme with voltage feedback circuit and low-noise preamplifier

    International Nuclear Information System (INIS)

    We analyzed the dc SQUID with voltage feedback circuit (VFC) and a low-noise room-temperature preamplifier to evaluate the feasibility of a low-noise SQUID direct-coupled readout scheme (DRS), possibly eliminating the need for a two-stage scheme employing a SQUID preamplifier. The passive VFC, connected in parallel to the SQUID, consists of a resistor Rs in series with an inductor L s. This inductor is coupled to the SQUID by a mutual inductance Ms. The purpose of the VFC is to increase the SQUID’s flux-to-voltage transfer coefficient ∂V/∂Φ, thus reducing the preamplifier noise contribution δΦpreamp. However, at the same time, VFC introduces the thermal noise of Rs, δΦR, which may not be negligible. Generally, the noise of the readout scheme, δΦreadout, may thus include both δΦpreamp and δΦR, i.e., δΦreadout2 = δΦpreamp2 + δΦR2. To characterize the SQUID operation with VFC we introduced two dimensionless parameters, r = Rs/Rd and Δ = (M s/Mdyn) − (Rs/R d), where Rd and Mdyn = 1/(∂i/∂Φ) are dynamic properties of the SQUID itself. For assumed intrinsic SQUID parameters, we then numerically analyzed the dependence of δΦreadout noise components on r and Δ to determine their suitable ranges and the minimum of δΦreadout. To verify our analysis, we experimentally characterized, in liquid helium, three niobium SQUIDs with VFC, having suitably chosen r and Δ. The measured SQUID system flux noise was on the order of 1 μΦ0/√Hz, comparable to the intrinsic noise of the SQUID itself. The deduced equivalent voltage noise was comparable to that of a SQUID preamplifier in the two-stage readout. Simple single-stage ultra-low-noise SQUID DRS readout was thus demonstrated. (paper)

  19. Model of Auctioneer Estimation of Swordtip Squid (Loligo edulis) Quality

    Science.gov (United States)

    Nakamura, Makoto; Matsumoto, Keisuke; Morimoto, Eiji; Ezoe, Satoru; Maeda, Toshimichi; Hirano, Takayuki

    The knowledge of experienced auctioneers regarding the circulation of marine products is an essential skill and is necessary for evaluating product quality and managing aspects such as freshness. In the present study, the ability of an auctioneer to quickly evaluate the freshness of swordtip squid (Loligo edulis) at fish markets was analyzed. Evaluation characteristics used by an auctioneer were analyzed and developed using a fuzzy logic model. Forty boxes containing 247 swordtip squid with mantles measuring 220 mm that had been evaluated and assigned to one of five quality categories by an auctioneer were used for the analysis and the modeling. The relationships between the evaluations of appearance, body color, and muscle freshness were statistically analyzed. It was found that a total of four indexes of the epidermis color strongly reflected evaluations of appearance: dispersion ratio of the head, chroma on the head-end mantle and the difference in the chroma and brightness of the mantle. The fuzzy logic model used these indexes for the antecedent-part of the linguistic rules. The results of both simulation and evaluations demonstrate that the model is robust, with the predicted results corresponding with more than 96% of the quality assignments of the auctioneers.

  20. Impact of SQUIDs on functional imaging in neuroscience

    International Nuclear Information System (INIS)

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

  1. Conductivity tomography based on pulsed eddy current with SQUID magnetometer

    International Nuclear Information System (INIS)

    Pulsed eddy current (EC) techniques have the advantage of potentially covering a broader depth range than standard single frequency EC testing. We developed a novel pulsed EC technique using a liquid-nitrogen cooled SQUID magnetometer. For two reasons, SQUID magnetometers are particularly well suited as sensors: first they constitute an extremely sensitive magnetic field sensor, second they measure the field directly which decays more slowly than its time derivative picked up by induction coils. A square waveform transmitter signal was used, with alternating slopes in order to eliminate drift effect, and stacking synchronous to the power line frequency in order to improve signal-to-noise. The early time (high frequency) data of the recorded transient correspond to the upper layers of the conducting medium, while late time data or low frequencies deliver information on deep layers. Measurements of cracks at different depths in a stacked aluminum sample are presented. From the measured data, the apparent conductivity of the sample was calculated for each position and depth by applying a technique known from geophysical data interpretation. Thus, the position and depth of the crack was determined from the tomographic conductivity image of the sample

  2. SQUID-Detected In Vivo MRI at Microtesla Magnetic Fields

    Energy Technology Data Exchange (ETDEWEB)

    Moble, Michael; Myers, Whittier R; Lee, SeungKyun; Kelso, Nathan; Hatridge, Michael; Pines, Alexander; Clarke, John

    2005-06-01

    We use a low transition temperature (T{sub c}) Super-conducting Quantum Interference Device (SQUID) to perform in vivo magnetic resonance imaging (MRI) at magnetic fields around 100 microtesla, corresponding to proton Larmor frequencies of about 5 kHz. In such low fields, broadening of the nuclear magnetic resonance lines due to inhomogeneous magnetic fields and susceptibility variations of the sample are minimized, enabling us to obtain high quality images. To reduce environmental noise the signal is detected by a second-order gradiometer, coupled to the SQUID, and the experiment is surrounded by a 3-mm thick Al shield. To increase the signal-to-noise ratio (SNR), we prepolarize the samples in a field up to 100 mT. Three-dimensional images are acquired in less than 6 minutes with a standard spin-echo phase-encoding sequence. Using encoding gradients of {approx}100 {micro}T/m we obtain three-dimensional images of bell peppers with a resolution of 2 x 2 x 8 mm{sup 3}. Our system is ideally suited to acquiring images of small, peripheral parts of the human body such as hands and arms. In vivo images of an arm, acquired at 132 {micro}T, show 24-mm sections of the forearm with a resolution of 3 x 3 mm{sup 2} and a SNR of 10. We discuss possible applications of MRI at these low magnetic fields.

  3. SQUID-based beam position monitoring for proton EDM experiment

    Science.gov (United States)

    Haciomeroglu, Selcuk

    2014-09-01

    One of the major systematic errors in the proton EDM experiment is the radial B-field, since it couples the magnetic dipole moment and causes a vertical spin precession. For a proton with EDM at the level of 10-29 e.cm, 0.22 pG of B-field and 10.5 MV/m of E-field cause same vertical spin precession. On the other hand, the radial B-field splits the counter-rotating beams depending on the vertical focusing strength in the ring The magnetic field due to this split modulated at a few kHz can be measured by a SQUID-magnetometer. This measurement requires the B-field to be kept less than 1 nT everywhere around the ring using shields of mu-metal and aluminum layers. Then, the SQUID measurements involve noise from three sources: outside the shields, the shields themselves and the beam. We study these three sources of noise using an electric circuit (mimicking the beam) inside a magnetic shielding room which consists two-layers of mu-metal and an aluminum layer.

  4. Impact of SQUIDs on functional imaging in neuroscience

    Science.gov (United States)

    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.

  5. The fabrication and characterization of nano-SQUIDs based on Nb thin films

    International Nuclear Information System (INIS)

    Highlights: • We developed a nano-SQUID fabrication process starting from a high-quality thin film. • The fabricated nano-SQUIDs exhibited flux modulation depth up to 10.3% at 4.6 K. • The measured data agreed with the Ginzburg–Landau simulation. • We found that a small critical current <50 μA is important for a deep flux modulation. • The suggestions in improving the nano-SQUID’s performance were discussed. - Abstract: SQUIDs with nano-junctions (or nano-SQUIDs) are able to be miniaturized into nanoscale to measure a single Bohr magneton. Here, we reported the development of a fabrication process for Nb (niobium) nano-SQUIDs using the thin film deposition and the electron-beam lithography technology. The developed process started from a high-quality superconducting thin film so that it is compatible with a variety of film growing techniques. The as-fabricated nano-SQUIDs exhibited functional flux modulation depth up to 10.3% at 4.6 K, in agreement with the numerical simulation based on the Ginzburg–Landau equation. By further comparing the results from both experiments and simulations, we found that a small critical current below ∼50 μA played a leading role in order to obtain a decent flux-modulation depth for Nb nano-SQUIDs

  6. Development and investigation of novel single-layer gradiometers using highly balanced gradiometric SQUIDs

    International Nuclear Information System (INIS)

    The sensitivity of galvanically coupled single-layer gradiometers on bicrystal substrates for homogeneous magnetic fields can be minimized by an increase of the balance, which is the ratio of the effective area of the antennas and the effective area of the SQUID. In this paper, we describe possible realizations of new gradiometric SQUIDs (G-SQUIDs) on 10x10 mm2 STO-bicrystal substrates, which minimize the effective area of the SQUID, and therefore the parasitic area of the gradiometer, to 34 μm2. We integrate these gradiometric SQUIDs in well-defined gradiometer antennas. The G-SQUID layouts with coupling inductances between 20 pH and 100 pH do not show any dependence of the parasitic area from the SQUID inductance. With a gradient field resolution of 1.6 pT(cm√Hz)-1 (white, unshielded) at 24 pH and 1.8 pT(cm√Hz)-1 at 55 pH, these gradiometers possess outstanding noise characteristics. So the balance of comparable conventional gradiometers, which show values of about 100, can be increased by more than an order of magnitude to 1070 with the new layouts. (author)

  7. The fabrication and characterization of nano-SQUIDs based on Nb thin films

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xixi; Liu, Xiaoyu; Wang, Hao; Chen, Lei, E-mail: leichen@mail.sim.ac.cn; Wang, Zhen

    2015-08-15

    Highlights: • We developed a nano-SQUID fabrication process starting from a high-quality thin film. • The fabricated nano-SQUIDs exhibited flux modulation depth up to 10.3% at 4.6 K. • The measured data agreed with the Ginzburg–Landau simulation. • We found that a small critical current <50 μA is important for a deep flux modulation. • The suggestions in improving the nano-SQUID’s performance were discussed. - Abstract: SQUIDs with nano-junctions (or nano-SQUIDs) are able to be miniaturized into nanoscale to measure a single Bohr magneton. Here, we reported the development of a fabrication process for Nb (niobium) nano-SQUIDs using the thin film deposition and the electron-beam lithography technology. The developed process started from a high-quality superconducting thin film so that it is compatible with a variety of film growing techniques. The as-fabricated nano-SQUIDs exhibited functional flux modulation depth up to 10.3% at 4.6 K, in agreement with the numerical simulation based on the Ginzburg–Landau equation. By further comparing the results from both experiments and simulations, we found that a small critical current below ∼50 μA played a leading role in order to obtain a decent flux-modulation depth for Nb nano-SQUIDs.

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

    Science.gov (United States)

    Masunee, Niyada; Chaiprapat, Supapan; Waiyagan, Kriangkrai

    2013-07-01

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

  9. Statistical characterization of voltage-biased SQUIDs with weakly damped junctions

    International Nuclear Information System (INIS)

    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. (paper)

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

    International Nuclear Information System (INIS)

    We investigated behavior of HTS-dc-SQUID gradiometers with ramp-edge Josephson junctions (JJs) in ac and dc magnetic fields. In the both fields, the gradiometers show higher durability against entry of flux vortices than SQUIDs with bicrystal JJs. A robot-based SQUID NDE system utilizing the gradiometer was developed in an unshielded environment. Detectability of the system to detect non-through cracks in double-layer structures was demonstrated. A new excitation coil was applied to detect cracks that oriented vertical and parallel to the baseline of the gradiometer. In this paper, we investigated detailed behavior of novel HTS-dc-SQUID gradiometers with ramp-edge Josephson junctions (JJs) in both an ac magnetic field and a dc magnetic field. In the both fields, the novel gradiometers shows the superior performance to the conventional YBa2Cu3O7-x (YBCO) HTS-dc-SQUID gradiometer and a bare HTS-dc-SQUID ring with bicrystal JJs concerning durability against entry and hopping of flux vortices, probably due to their differential pickup coils without a grain boundary and multilayer structure of the ramp-edge JJs. A robot-based compact HTS-SQUID NDE system utilizing the novel gradiometer was reviewed, and detectability of the system to detect non-through cracks in a carbon fiber reinforced plastic (CFRP)/Al double-layer structure was demonstrated. A new excitation coil in which the supplied currents flowed in the orthogonal directions was applied to detect cracks that oriented vertical and parallel to the baseline of the gradiometer.

  11. In vitro antioxidant, antimutagenic and antiproliferative activities of collagen hydrolysates of jumbo squid (Dosidicus gigas byproducts

    Directory of Open Access Journals (Sweden)

    Guadalupe Miroslava Suárez-Jiménez

    2015-09-01

    Full Text Available AbstractHydrolysates from two different jumbo squid byproducts (fins and arms, produced by trypsin and protease type XIV were compared on the basis of their antioxidant (DPPH and ABTS radical scavenging assays, antimutagenic (Ames test and antiproliferative (Transformation cell proliferation in M12.C3F6 murine cells activities. Jumbo squid arms had higher content of collagen than fins, and their hydrolysates had the highest antioxidant activity. Also, jumbo squid arm-derived collagen hydrolyzed with protease XIV showed the highest antimutagenic activity. The four hydrolysates obtained showed low antiproliferative activity, however they are susceptible for further studies to be applied as food additives.

  12. Sensory, chemical and bacteriological changes during storage of iced squid ( Todaropsis eblanae )

    DEFF Research Database (Denmark)

    Paarup, T.; Sanchez, J.A.; Moral, A.;

    2002-01-01

    Aims: To relate sensory shelf-life of iced whole and gutted squid to bacterial growth and chemical changes. Methods and Results: Cooked mantles from whole and gutted individuals were rejected after 10 and 12 days of storage, respectively, due to ammoniacal off-odours. Rate of production of both...... recently-captured squid showed that the main flora consisted of Photobacterium phosphoreum. Conclusions: Spoilage of iced squid is likely to result from a combination of autolytic and bacterial changes. Agmatine seems to be an excellent freshness indicator. Photobacterium phosphoreum may contribute to...

  13. A low noise dc-SQUID based on Nb/Al-AlOx/Nb Josephson junctions

    International Nuclear Information System (INIS)

    Low noise dc SQUIDs based on a Nb/Al-AlOx/Nb Josephson junction technology have been developed. The design has been optimized for improved control of the resonances. An eight-level process has been used for device fabrication. Flux noise levels of 2.8x10-7Φ0/√Hz at 1 kHz and 1.5x10-6Φ0/√Hz at 1 Hz have been measured for an integrated SQUID magnetometer having 3 μm2 junctions, a 12-turn input coil, and a dc SQUID inductance Ldc = 11 pH. (orig.)

  14. Generation of N-qubit W state with rf-SQUID qubits by adiabatic passage

    CERN Document Server

    Deng, Z J; Gao, K L

    2006-01-01

    A simple scheme is presented to generate n-qubit W state with rf-superconducting quantum interference devices (rf-SQUIDs) in cavity QED through adiabatic passage. Because of the achievable strong coupling for rf-SQUID qubits embedded in cavity QED, we can get the desired state with high success probability. Furthermore, the scheme is insensitive to position inaccuracy of the rf-SQUIDs. The numerical simulation shows that, by using present experimental techniques, we can achieve our scheme with very high success probability, and the fidelity could be eventually unity with the help of dissipation.

  15. An analysis theory of symmetric dc SQUID driven by thermal noises

    International Nuclear Information System (INIS)

    An analysis expression for the stationary probability distribution of the symmetric superconducting quantum interference device with two Josephson junctions (dc SQUID) driven by thermal noise is derived from two-dimensional Fokker-Planck equations where the potential condition is satisfied. The analytical formulae for SQUID characteristics, e.g. the circulating current, the current-voltage relationship and the transfer function, are obtained by using the probability distribution. The 'ripple' phenomenon of the circulating current versus the applied flux, the effects of thermal fluctuations on current-voltage relationship and the optimum operating condition of dc SQUID system are represented

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

    International Nuclear Information System (INIS)

    This thesis is concerned with the development of Superconducting Quantum Interference Device (SQUID) gradiometers based on the high temperature superconductor YBa2Cu3O7-δ (YBCO). A step-edge Josephson junction fabrication process was developed to produce sufficiently steep (>60 deg) step-edges such that junctions exhibited RSJ-like current-voltage characteristics. The mean ICRN product of a sample of twenty step-edge junctions was 130μV. Step-edge dc SQUIDs with inductances between 67pH and 114pH were fabricated. Generally the SQUIDs had an intrinsic white flux noise in the 10-30μΦ0/√Hz range, with the best device, a 70pH SQUID, exhibiting a white flux noise of 5μΦ0/√Hz. Different first-order SQUID gradiometer designs were fabricated from single layers of YBCO. Two single-layer gradiometer (SLG) designs were fabricated on 10x10mm2 substrates. The best balance and lowest gradient sensitivity measured for these devices were 1/300 and 308fT/cm√Hz (at 1 kHz) respectively. The larger baseline and larger flux capture area of the pick-up loops in a large area SLG design, fabricated on 30x10mm2 substrates, resulted in significant improvements in the balance and gradient field sensitivity with 1/1000 and 50fT/cm√Hz (at 1kHz) measured respectively. To reduce the uniform field effective area of SLOs and therefore reduce the direct pick-up of environmental field noise when operated unshielded, a novel gradiometric SQUID (G-SQUID) device was developed. Fabricated from a single layer of YBCO, the G-SQUIDs with inductances of 67pH, had small uniform field effective areas of approximately 2μm2 - more than two orders of magnitude smaller than the uniform field effective areas of conventional narrow linewidth SQUIDs of similar inductance. Two designs of G-SQUID were fabricated on 10x10mm2 substrates. Due to their small effective areas, when cooled unshielded these devices showed no increase in their white flux noise. The best balance achieved for a G-SQUID was

  17. A SQUID readout system for a superconducting gyroscope. [superconducting quantum interference device

    Science.gov (United States)

    Hendricks, J. B.

    1975-01-01

    A design of a read out system for a superconducting gyroscope to be used in an orbiting gyroscope relativity experiment is discussed. The 'London Moment' of the superconducting rotor, which lies along the spin axis of the rotor, will be measured with a SQUID-type magnetometer. The SQUID will be built around the gyro rotor, with a very close spacing to give an inductance between 10 millionths and 1 millionth Hy. A SQUID of this design should resolve 2.07 times 10 to the minus 19th weber. The angular resolution of the gyroscope will then be 0.0035 arc-second, which is sufficient for the intended experiment.

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

    International Nuclear Information System (INIS)

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

  19. A SQUID-based microwave cavity search for dark-matter axions

    Energy Technology Data Exchange (ETDEWEB)

    Asztalos, S J; Carosi, G; Hagmann, C; Kinion, D; van Bibber, K; Hotz, M; Rosenberg, L; Rybka, G; Hoskins, J; Hwang, J; Sikivie, P; Tanner, D B; Bradley, R; Clarke, J

    2009-10-21

    Axions in the {mu}eV mass range are a plausible cold dark matter candidate and may be detected by their conversion into microwave photons in a resonant cavity immersed in a static magnetic field. The first result from such an axion search using a superconducting first-stage amplifier (SQUID) is reported. The SQUID amplifier, replacing a conventional GaAs field-effect transistor amplifier, successfully reached axion-photon coupling sensitivity in the band set by present axion models and sets the stage for a definitive axion search utilizing near quantum-limited SQUID amplifiers.

  20. Hysteretic behaviour of nanoSQUIDs-prospective application as trapped-vortex memory

    International Nuclear Information System (INIS)

    We have studied the critical current-magnetic field dependence, Ic(B), of nanoSQUIDs. The vortex penetration field of a Nb/Au bilayer film was determined from the hysteretic behaviour of the nanoSQUID's Ic(B) pattern. The current-voltage characteristics of Nb/Au bilayer microbridges were also studied. The vortex penetration field was found to be much lower than the Nb single-layer counterpart. These properties suggest that a nanoSQUID may be a potential trapped-vortex memory device, which is discussed.

  1. Magnetic imaging of unconventional superconductors by scanning SQUID microscopy

    International Nuclear Information System (INIS)

    We present the development of a scanning SQUID/AFM microscope and measurements performed on different samples. The microscope can take topographic and magnetic images simultaneously. The magnetic resolution is of the order of 10-4Φ0√Hz and the spatial resolution of the SQUIDs used in this thesis goes up to 600 nm. The scanning range is 70 μm * 85 μm. The temperature range accessible is between 200 mK and 10 K at the time of writing. Measurements on a thin rhenium film (80 nm) give an estimate of the minimal pinning force of a vortex of about 3.9 * 10-16 N. Furthermore, the penetration depth λ on this sample was determined as a function of temperature. For T → 0, λ →79 nm. We have for the first time shown local measurements of the domain structure of the superconducting ferromagnet UCoGe and determined the average domain size in the virgin state (10 μm). By magnetic imaging we were capable of determining the magnetic field difference above opposite domains along the c-axis to be 45 G and 16 G along the b-axis. Due to these magnetic field measurements we were able to give an upper limit for the domain wall width (∼ 1μm) and domain reconstruction depth (100 nm). This is supported by simple calculations leading to a domain wall width of several angstroms. Thus UCoGe can be considered an ideal Ising ferromagnet. Different possible domain structures for an Ising ferromagnet have been discussed. The complicated domain structure found in the zero field cooled virgin state corresponds to up domains embedded in larger down domains and vice versa. We have shown evidence for coexistence of superconductivity and ferromagnetism. The weak Meissner effect can be explained by a spontaneous vortex state, put forward by other groups. Numerical simulations suggest that the strong magnetic background signal and the limited spatial and magnetic resolution of the used SQUID made it difficult to resolve the expected spontaneous vortex state. The relaxation of the domain

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2006-05-01

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

  4. Macroscopic quantum tunneling in a dc SQUID: Instanton splitting

    International Nuclear Information System (INIS)

    The theory of macroscopic quantum tunneling is applied to a current-biased dc SQUID which constitutes a system of two interacting quantum degrees of freedom coupled to the environment. The decay probability is obtained in the exponential approximation for the overdamped case. Close to the critical driving force of the system, the decay of the metastable state is determined by a unique instanton solution describing the symmetric decay of the phases in each of the two Josephson juctions. Upon reducing the external driving force a new regime is reached where the instanton splits. The doubling of the decay channels reduces the decreasing of the decay rate in the quantum regime. A current-temperature phase diagram is constructed based on the Landau theory of phase transitions. Depending on the external parameters the system develops either a first- or a second-order transition to the split-instanton regime

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

    Science.gov (United States)

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

    2005-03-01

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

  6. The Transition from Stiff to Compliant Materials in Squid Beaks

    Science.gov (United States)

    Miserez, Ali; Schneberk, Todd; Sun, Chengjun; Zok, Frank W.; Waite, J. Herbert

    2008-03-01

    The beak of the Humboldt squid Dosidicus gigas represents one of the hardest and stiffest wholly organic materials known. As it is deeply embedded within the soft buccal envelope, the manner in which impact forces are transmitted between beak and envelope is a matter of considerable scientific interest. Here, we show that the hydrated beak exhibits a large stiffness gradient, spanning two orders of magnitude from the tip to the base. This gradient is correlated with a chemical gradient involving mixtures of chitin, water, and His-rich proteins that contain 3,4-dihydroxyphenyl-L-alanine (dopa) and undergo extensive stabilization by histidyl-dopa cross-link formation. These findings may serve as a foundation for identifying design principles for attaching mechanically mismatched materials in engineering and biological applications.

  7. SQUID-Detected Microtesla MRI in the presence of Metal

    Energy Technology Data Exchange (ETDEWEB)

    Moessle, Michael; Han, Song-I.; Myers, Whittier; Lee, Seung-Kyun; Kelso, Nathan; Hatridge, Michael; Pines, Alexander; Clarke, John

    2006-09-06

    In magnetic resonance imaging (MRI) performed at fields of 1 T and above, the presence of a metal insert can distort the image because of susceptibility differences within the sample and modification of the radiofrequency fields by screening currents. Furthermore, it is not feasible to perform nuclear magnetic resonance (NMR) spectroscopy or acquire a magnetic resonance image if the sample is enclosed in a metal container. Both problems can be overcome by substantially lowering the NMR frequency. Using a microtesla imaging system operating at 2.8 kHz, with a superconducting quantum interference device (SQUID) as the signal detector, we have obtained distortion-free images of a phantom containing a titanium bar and three-dimensional images of an object enclosed in an aluminum can; in both cases high-field images are inaccessible.

  8. The transition from stiff to compliant materials in squid beaks.

    Science.gov (United States)

    Miserez, Ali; Schneberk, Todd; Sun, Chengjun; Zok, Frank W; Waite, J Herbert

    2008-03-28

    The beak of the Humboldt squid Dosidicus gigas represents one of the hardest and stiffest wholly organic materials known. As it is deeply embedded within the soft buccal envelope, the manner in which impact forces are transmitted between beak and envelope is a matter of considerable scientific interest. Here, we show that the hydrated beak exhibits a large stiffness gradient, spanning two orders of magnitude from the tip to the base. This gradient is correlated with a chemical gradient involving mixtures of chitin, water, and His-rich proteins that contain 3,4-dihydroxyphenyl-L-alanine (dopa) and undergo extensive stabilization by histidyl-dopa cross-link formation. These findings may serve as a foundation for identifying design principles for attaching mechanically mismatched materials in engineering and biological applications. PMID:18369144

  9. Braking Performance of a Biomimetic Squid-Like Underwater Robot

    Institute of Scientific and Technical Information of China (English)

    Md.Mahbubar Rahman; Sinpei Sugimori; Hiroshi Miki; Risa Yamamoto; Yugo Sanada; Yasuyuki Toda

    2013-01-01

    In this study,the braking performance of the undulating fin propulsion system ofa biomimetic squid-like underwater robot was investigated through free run experiment and simulation of the quasi-steady mathematical model.The quasi-steady equations of motion were solved using the measured and calculated hydrodynamic forces and compared with free-run test results.Various braking strategies were tested and discussed in terms of stopping ability and the forces acting on the stopping stage.The stopping performance of the undulating fin propulsion system tured out to be excellent considering the short stopping time and short stopping distance.This is because of the large negative thrust produced by progressive wave in opposite direction.It was confirmed that the undulating fin propulsion system can effectively perform braking even in complex underwater explorations.

  10. An integrated DC SQUID magnetometer with variable additional positive feedback

    International Nuclear Information System (INIS)

    An easily adjustable direct-coupled magnetometer is presented. A typical usable voltage swing of 30 mu V and noise levels of down to 1.13 fT Hz-1/2 at 1 kHz have been achieved with additional positive feedback (APF). A compensation circuit integrated into the magnetometer chip allows the reduction of APF gain in three steps within a factor of 1.8, by simply adding one or two bond connections on the magnetometer chip. In this way the tolerance of the critical current I0 is enlarged from ±10% to ±27% at the traditional SQUID working point. If additionally the shunt resistors are trimmed by plasma etching the tolerance of I0 can be increased further to about ±55%. (author)

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

    International Nuclear Information System (INIS)

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

  12. Detection of Rapid Atrial Arrhythmias in SQUID Magnetocardiography

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-10-15

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

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

    Science.gov (United States)

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

    2014-03-01

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

  14. Some new aspects concerning the X-band SQUID for the measurement of RF attenuation

    International Nuclear Information System (INIS)

    The performance of a microwave-pumped SQUID with niobium, tantalum, and vanadium point-contact junctions is evaluated. The SQUIDs were developed for measuring RF attenuation in the frequency range 0-1 GHz. The equipment described here is controlled by a desktop computer and can be used for measuring attenuation up to 60 dB. Also described is a simple analytical theory for the operation of the X-band SQUID. The experiments support the conclusion that the most important limitations on RF measurements at high frequencies and high signal levels are the voltage and the power dependence of the quasi-particle conductance of the Josephson junction. This source of error is treated in some detail. It is shown that a SQUID can be used successfully for RF measurements at very high signal frequencies if a junction material with a sufficiently low critical temperature is chosen

  15. Relativistic dynamics of domain wall in one-dimensional SQUID array

    International Nuclear Information System (INIS)

    We investigate the dynamics of a domain wall in a one-dimensional array of superconducting quantum interference device (SQUID) composed of three conventional Josephson junctions and a π-junction. The domain wall is formed between two domains with oppositely circulating current through the SQUID loop. It is shown that the SQUIDs in this array can be approximately described by a double sine-Gordon (DSG) model which obeys Einstein's special theory of relativity. We conduct numerical simulations of a discrete DSG equation and show that the domain wall propagates solitonically through the SQUID array and exhibits quasi-relativistic behavior, such as the Lorentz contraction and the relativistic time dilation, which agrees reasonably well with the predictions from a relativistic equation of motion of a particle, whose rest mass is extremely small compared to that of a single electron.

  16. Time-Resolved SQUID Sensor with a Nyquist Frequency up to 25 GHz

    Science.gov (United States)

    Cui, Z.; Wang, Y. H.; Kratz, P.; Rosenberg, A. J.; Watson, C. A.; Sochnikov, I.; Fung, Y.-K.-K.; Gibson, G.; Kirtley, J. R.; Ketchen, M. B.; Moler, K. A.

    We demonstrate a time-resolved scanning Superconducting QUantum Interference Device (SQUID) sensor with an expected maximum sampling rate of 50 GHz. The time-resolved SQUID sampler is operated by a pump-probe pulse sequence and will be particularly useful in studying high-frequency magnetic devices and the transient behavior of magnetic materials. The high sampling rate is achieved through a Josephson-interferometry technique developed at IBM. We tested our sampler with flux signals of order 10 mΦ0 (where Φ0 is the magnetic flux quantum), which corresponds to 25 million Bohr magnetons located 1 micron directly below the pickup loop. Operating in this regime, our sampler will have much higher sensitivity than bulk sensors like conventional SQUIDs and much larger spatial scanning range than single-spin sensors like NV centers. The SQUID sampler will thus be well-suited to characterize individual mesoscopic samples as well as bulk samples with mesoscopic features.

  17. Sensory, chemical and bacteriological changes during storage of iced squid ( Todaropsis eblanae )

    DEFF Research Database (Denmark)

    Paarup, T.; Sanchez, J.A.; Moral, A.; Christensen, H.; Bisgaard, M.; Gram, Lone

    2002-01-01

    Aims: To relate sensory shelf-life of iced whole and gutted squid to bacterial growth and chemical changes. Methods and Results: Cooked mantles from whole and gutted individuals were rejected after 10 and 12 days of storage, respectively, due to ammoniacal off-odours. Rate of production of both...... ammonia and trimethylamine was highest in the whole lot. Agmatine, which was only present in trace amounts in freshly-caught squid, increased rapidly in both lots. The main microflora at the time of sensory rejection of iced whole squid included Gram- negative, motile and non-fermentative rods, which were...... psychrophilic and had a requirement for NaCl. 16S rDNA sequence analyses identified the strains as belonging to the genus Pseudoalteromonas . Shewanella putrefaciens , Pseudoalteromonas sp. and Pseudomonas sp. dominated in spoiled gutted squid. Identification of strains from the stomach and digestive gland of...

  18. 78 FR 3346 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Science.gov (United States)

    2013-01-16

    ... rule for 2013 MSB specifications and management measures was published on November 19, 2012 (77 FR... United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Specifications and Management Measures... measures for Atlantic mackerel, and 2013 specifications for butterfish. Specifications for longfin...

  19. Fabrication of SQUIDs with Nb/Ru/Sr2RuO4 junctions

    International Nuclear Information System (INIS)

    We have fabricated superconducting quantum interference devices (SQUIDs) using Nb/Ru/Sr2RuO4 junctions. The superconducting loop of a Nb-Sr2RuO4 hybrid dc SQUID is composed of Nb, Sr2RuO4 and two Nb/Ru/Sr2RuO4 junctions, and made by building a Nb bridge between two individual Ru micro inclusions on the ab-plane surface of the Ru-Sr2RuO4 eutectic system. We measure the critical current between Nb and Sr2RuO4 parts of such dc-SQUIDs, which oscillates with every flux quantum through the SQUID loop.

  20. Multiplexed readout of MMC detector arrays using non-hysteretic rf-SQUIDs

    CERN Document Server

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

    2013-01-01

    Metallic magnetic calorimeters (MMCs) are widely used for various experiments in fields ranging from atomic and nuclear physics to x-ray spectroscopy, laboratory astrophysics or material science. Whereas in previous experiments single pixel detectors or small arrays have been used, for future applications large arrays are needed. Therefore, suitable multiplexing techniques for MMC arrays are currently under development. A promising approach for the readout of large arrays is the microwave SQUID multiplexer that operates in the frequency domain and that employs non-hysteretic rf-SQUIDs to transduce the detector signals into a frequency shift of high $Q$ resonators which can be monitored by using standard microwave measurement techniques. In this paper we discuss the design and the expected performance of a recently developed and fabricated 64 pixel detector array with integrated microwave SQUID multiplexer. First experimental data were obtained characterizing dc-SQUIDs with virtually identical washer design.

  1. Multi-pixel readout of transition-edge sensors using a multi-input SQUID

    International Nuclear Information System (INIS)

    We propose a new method to read out signals from a TES (superconducting Transition-Edge Sensor) calorimeter array with a single or a small number of SQUIDs. Since phonon noise and Johnson noise of a calorimeter can be made very small in these calorimeters, an increase in noise, thus a degradation of energy resolution by adding signals from plural pixels together at some stage of signal processing may be acceptable for some applications of TES calorimeters. We propose to use a SQUID with multi-input coils which will sense signals from different pixels. The input coils of a SQUID are electrically well-isolated from each other. The pixel that generates a signal can be identified by utilizing additional information, such as the pulse shape. We studied the feasibility of this method with analysis and simulations, and show for example, that a 16x16 pixel array can be read out with 16 SQUIDs

  2. A 200 h-bar two-stage dc SQUID amplifier for resonant gravitational wave detectors

    International Nuclear Information System (INIS)

    Starting from commercial chips, a two-stage dc superconducting quantum interference device (SQUID) was developed in order to use it as a low-noise amplifier on the resonant gravitational wave detector AURIGA. The SQUID was coupled to a high-Q electrical resonator, operating in the kilohertz frequency range, which was employed to simulate the real detector. The resonator was successfully stabilized by means of a capacitive damping network. SQUID additive noise and back-action noise were measured as functions of temperature. The best noise temperature of the SQUID amplifier, measured at 1.5 K, was better than 16 μK, and corresponds to a minimum detectable energy of 200 resonator quanta

  3. Multichannel SQUID system detecting tangential components of the cardiac magnetic field

    Science.gov (United States)

    Tsukada, Keiji; Haruta, Yasuhiro; Adachi, Akira; Ogata, Hisanao; Komuro, Takanori; Ito, Tsuyoshi; Takada, Youichi; Kandori, Akihiko; Noda, Yasunaga; Terada, Yasushi; Mitsui, Toshio

    1995-10-01

    The 32-channel SQUID system described here is used for diagnosing heart disease by measuring the x and y components of the cardiac magnetic field. To detect a magnetic field parallel to the body surface, it uses a compact hybrid superconducting quantum interference device (SQUID) gradiometer consisting of a planar pickup coil (fabricated using thin-film techniques) and a square double-washer dc-SQUID having large voltage-flux transfer function. The SQUIDs are operated in a flux-locked mode using simple readout circuits connected directly to the preamplifier without additional positive feedback. The system is installed in a magnetically shielded room in a hospital. A low noise characteristics lower than 10 ft/√ Hz in a white noise is obtained in the hospital. Examples of tangential magnetocardiogram (MCG) measurements presented here show that the MCG obtained using this gradiometer makes it easy to visually estimate the electrophysiological behavior of the heart.

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

    International Nuclear Information System (INIS)

    International available SQUID systems, as used for example in biomagnetic research, obtain high sensitivities for magnetic fields or magnetic fieldgradients. However, these systems were optimised for operation in magnetically shielded rooms. Goal of this project was to develop SQUIDs suppressing the external noise and therefore are able to operate without external shielding in normal environments. As a consequence, the required Nb/AlOx/Nb technology has also been developed. The resulting planar SQUID gradiometers as produced at the IPHT, reached a suppression of homogeneous fields up to 5 x 104 for a magnetic field sensitivity c, project. SQUID gradiometers, produced using YBCO technology, were successfully operated in non shielded eddy current NDE measurements in the lab. (orig.)

  5. Low noise dc SQUIDs fabricated in Nb-Al2O3-Nb trilayer technology

    International Nuclear Information System (INIS)

    This paper reports on the design, fabrication, and testing of all-refractory dc SQUIDs in Nb---Al2O3---Nb trilayer technology that have noise performance. A variety of SQUID designs were incorporated as part of a trilayer process development test vehicle. SQUID inductance, junction area, and resistive shunt geometry were varied in matrix fashion to give SQUIDs with near optimum parameter values for a factor of five range in Josephson current density and shunt sheet resistance. The devices were fabricated using a selective niobium anodization process (SNAP) with a minimum feature size of 2 μm. The base electrode and Nb wiring were patterned with dry etching and the junction areas were defined by anodization; the Ti resistors were patterned with a lift-off process. Current density on different wafers was varied from 400 to 1000 A/cm2 with junction Vm s typically 60 mV

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

    Digital Repository Service at National Institute of Oceanography (India)

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

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

  7. SQUID-Detected Magnetic Resonance Imaging in MicroteslaFields

    Energy Technology Data Exchange (ETDEWEB)

    Moessle, Michael; Hatridge, Michael; Clarke, John

    2006-08-14

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

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

    Science.gov (United States)

    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.

  9. A SQUID biomagnetometer system for measurement of spinal cord evoked magnetic fields

    International Nuclear Information System (INIS)

    We developed a 24-channel superconducting quantum interference devices (SQUIDs) biomagnetometer system for the measurement of the evoked magnetic field from stimulated spinal cords. The system uses composite LTc SQUID gradiometers and can observe the three-dimensional components of the magnetic field. With the system, we could successfully record the evoked magnetic fields corresponding to neuronal signals transmitting in the spinal cord of a cat. (author)

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

    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.

  12. Trophic relationships between sperm whales and the jumbo squid using stable isotopes of C and N

    OpenAIRE

    Ruiz Cooley, R.I.; Gendron, Diane; Aguíñiga García, Sergio; Mesnick, S.L.; Carriquiry, L.D.

    2004-01-01

    The trophic position and the predator–prey relationship between the sperm whale Physeter macrocephalus and the jumbo squid Dosidicus gigas were examined by measuring stable isotope ratios of carbon and nitrogen. Skin samples of sperm whales and muscle samples of small and large jumbo squid were collected between 1996 and 1999 in the Gulf of California. Gender determination through molecular analysis and field identification of size were used to identify adult male, female and immature male sp...

  13. The biology and ecology of the jumbo squid Dosidicus gigas (Cephalopoda) in Chilean waters: a review

    OpenAIRE

    Christian M Ibáñez; Roger D Sepúlveda; Patricio Ulloa; Friedemann Keyl; M. CECILIA PARDO-GANDARILLAS

    2015-01-01

    ABSTRACT. The jumbo squid Dosidicus gigas is the most abundant cephalopod species in the southeastern Pacific Ocean, which supports the biggest cephalopod fishery in the world. Due to its growing economic importance, the population growth and distributional expansion of this squid is being increasingly studied. Nevertheless, some basic features of the biology of D. gigas are still unknown or have been poorly investigated. In this review we summarize the known information regarding the biology...

  14. Revealing the potential of squid chitosan-based structures for biomedical applications

    OpenAIRE

    Reys, L. L.; S.S. Silva; Oliveira, Joaquim M.; Caridade, S. G.; Mano, J. F.; Silva, Tiago H.; Reis, R. L.

    2013-01-01

    In recent years, much attention has been given to different marine organisms, namely as potential sources of valuable materials with a vast range of properties and characteristics. In this work, β-chitin was isolated from the endoskeleton of the giant squid Dosidicus gigas and further deacetylated to produce chitosan. Then, the squid chitosan was processed into membranes and scaffolds using solvent casting and freeze-drying, respectively, to assess their potential biomedical application. The ...

  15. A widely tunable parametric amplifier based on a SQUID array resonator

    OpenAIRE

    Castellanos-Beltran, M. A.; Lehnert, K. W.

    2007-01-01

    We create a Josephson parametric amplifier from a transmission line resonator whose inner conductor is made from a series SQUID array. By changing the magnetic flux through the SQUID loops, we are able to adjust the circuit's resonance frequency and, consenquently, the center of the amplified band, between 4 and 7.8 GHz. We observe that the amplifier has gains as large as 28 dB and infer that it adds less than twice the input vacuum noise.

  16. Gradiometer Using Middle Loops as Sensing Elements in a Low-Field SQUID MRI System

    Science.gov (United States)

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

    2009-01-01

    A new gradiometer scheme uses middle loops as sensing elements in lowfield superconducting quantum interference device (SQUID) magnetic resonance imaging (MRI). This design of a second order gradiometer increases its sensitivity and makes it more uniform, compared to the conventional side loop sensing scheme with a comparable matching SQUID. The space between the two middle loops becomes the imaging volume with the enclosing cryostat built accordingly.

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

    OpenAIRE

    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 d...

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

    International Nuclear Information System (INIS)

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

  19. Gain, directionality and noise in microwave SQUID amplifiers: Input-output approach

    OpenAIRE

    Kamal, Archana; Clarke, John; Devoret, Michel

    2012-01-01

    We present a new theoretical framework to analyze microwave amplifiers based on the dc SQUID. Our analysis applies input-output theory generalized for Josephson junction devices biased in the running state. Using this approach we express the high frequency dynamics of the SQUID as a scattering between the participating modes. This enables us to elucidate the inherently nonreciprocal nature of gain as a function of bias current and input frequency. This method can, in principle, accommodate an...

  20. Quantum Down Conversion and Multipartite Entanglement via a Mesoscopic SQUID Ring

    OpenAIRE

    Stiffell, P. B.; Everitt, M. J.; Clark, T. D.; Harland, C J; Ralph, J. F.

    2005-01-01

    In this paper we study, by analogy with quantum optics, the superconducting quantum interference device (SQUID) ring mediated quantum mechanical interaction of an input electromagnetic field oscillator mode with two or more output oscillator modes at subintegers of the input frequency. We show that through the nonlinearity of the SQUID ring multiphoton downconversion can take place between the input and output modes with the resultant output photons being created in an entangled state. We als...

  1. Noise characterization of highly sensitive SQUID magnetometer systems in unshielded environments

    International Nuclear Information System (INIS)

    To measure the noise performance of highly sensitive SQUID magnetometer systems directly is nearly impossible due to superimposed external noise. In magnetically unshielded environments in particular one needs sophisticated methods in order to get an estimate of the intrinsic noise. We compare different approaches to estimate the noise of our latest SQUID magnetometer systems in the Earth’s magnetic field and compare the results with measurements in magnetic (and superconductive) shielding. (paper)

  2. Redistribution and Transformation in the South African Fishing Industry: The Case of the Squid Fishery

    OpenAIRE

    Sauer, W.; Britz, P.; Mather, D

    2000-01-01

    Political normalisation in South Africa during 1994, and the drafting of the Marine Living Resources Act 1998, led to the imperative to transform the fishing sector to more equitably reflect the racial demographics of the country. The squid fishery, like most other South African fisheries, has historically been dominated by white ownership of access rights and vessels. The squid fishery is an effort limited hand-jig fishery with each operator possessing permits for a certain numbe...

  3. HTSC-RF-SQUID sensors in magnetic fields: Characterisation and noise reduction; HTSL-rf-SQUID-Sensoren in Magnetfeldern: Charakterisierung und Stoersignalunterdrueckung

    Energy Technology Data Exchange (ETDEWEB)

    Bick, M.

    2001-07-01

    Due to their excellent sensitivity to magnetic fields, HTS SQUID sensors are widely used in many applications outside magnetic shielding, e.g. for geophysical exploration of ore and hydrocarbon deposits, for nondestructive evaluation of aircraft and bridge components and for the measurement of biomagnetic signals for diagnostic purposes. In this work, two main subjects are investigated which are essential for the realisation of highly sensitive SQUID systems for operation in a magnetically strongly disturbed environment, for example for application in magnetocardiography: the influence of magnetic fields on the operation of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}}-rf-washer-SQUIDs with step-edge Josephson junctions is investigated (section 3) and a method for the reduction of environmental magnetic noise is presented and characterised (section 4). (orig.)

  4. Identification of four squid species by quantitative real-time polymerase chain reaction.

    Science.gov (United States)

    Ye, Jian; Feng, Junli; Liu, Shasha; Zhang, Yanping; Jiang, Xiaona; Dai, Zhiyuan

    2016-02-01

    Squids are distributed worldwide, including many species of commercial importance, and they are often made into varieties of flavor foods. The rapid identification methods for squid species especially their processed products, however, have not been well developed. In this study, quantitative real-time PCR (qPCR) systems based on specific primers and TaqMan probes have been established for rapid and accurate identification of four common squid species (Ommastrephes bartramii, Dosidicus gigas, Illex argentinus, Todarodes pacificus) in Chinese domestic market. After analyzing mitochondrial genes reported in GenBank, the mitochondrial cytochrome b (Cytb) gene was selected for O. bartramii detection, cytochrome c oxidase subunit I (COI) gene for D. gigas and T. Pacificus detection, ATPase subunit 6 (ATPase 6) gene for I. Argentinus detection, and 12S ribosomal RNA (12S rDNA) gene for designing Ommastrephidae-specific primers and probe. As a result, all the TaqMan systems are of good performance, and efficiency of each reaction was calculated by making standard curves. This method could detect target species either in single or mixed squid specimen, and it was applied to identify 12 squid processed products successfully. Thus, it would play an important role in fulfilling labeling regulations and squid fishery control. PMID:26772407

  5. Material properties of Pacific hake, Humboldt squid, and two species of myctophids in the California Current.

    Science.gov (United States)

    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. PMID:25994685

  6. Making SQUIDs a practical tool for quantum detection and material characterization in the micro- and nanoscale

    International Nuclear Information System (INIS)

    The investigation of quantum effects and materials at low and ultra-low temperature often requires very sensitive measurements of weak magnetic signals, small electric currents or voltages. Superconducting Quantum Interference Devices (SQUIDs) have been proven as very attractive tools in this field. However, well established fabrication technology and readout techniques usually fail, particularly, when going to nanoscale magnetic detection where off- the-shelf devices can rarely be used. As an alternative to elaborate nanoSQUID technology, SQUID concepts for nanoscale magnetic detection which are employing conventional, and hence, reliable technology are discussed. Magnetic coupling of nano-sized samples to conventional SQUIDs, e.g. simple gradiometers or more complex devices as fully integrated susceptometers, can be improved significantly by integrating nanoscale detection loops into these devices. Furthermore, appropriate SQUID current sensors are a prerequisite for the readout of micro- and nanoSQUIDs and small-area detection coils. The conventionally made devices are intended for fabrication in moderate numbers to make them available for a broader community

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

    International Nuclear Information System (INIS)

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

  8. Progress in the development of non-hysteretic rf-SQUIDs for a multiplexed MMC readout

    International Nuclear Information System (INIS)

    Recently it was shown that the performance of single channel Metallic Magnetic Calorimeters (MMCs) meets the requirements of many applications like, for example, high resolution X-ray spectroscopy. Presently, a number of cryogenic multiplexing schemes are investigated to increase the channel count of MMC detector arrays significantly. A quite promising approach employs a so-called microwave SQUID multiplexer. Here, non-hysteretic unshunted rf-SQUIDs transduce the detector signals into a frequency shift of related superconducting microwave resonators with unique resonance frequencies. By injecting a microwave frequency comb and monitoring either phase or amplitude of each resonator, it is thus possible to infer the initial detector signals. Based on experimental results obtained with our first prototype SQUID multiplexer and numerical simulations we optimized our current multiplexer design concerning rf-SQUID layout, SQUID-to-resonator coupling and fabrication of the Nb/Al-AlOx/Nb Josephson junctions. We discuss advantages of the modified fabrication process, differences between both multiplexer designs, the expected performance improvements and present first measurements of this second generation SQUID multiplexer.

  9. Development of a HTS SQUID module for use with an external pickup coil

    International Nuclear Information System (INIS)

    We have developed HTS SQUID modules applicable to various systems, such as nondestructive evaluation and low-field NMR/MRI systems. The SQUID module consists of a directly coupled HTS planar gradiometer and a HTS multi-turn input coil, which are fabricated on separate substrates and stacked with a flip-chip configuration. Two types of input coils, 26-turns and 59-turns, are fabricated. The SQUID module is mounted on a printed circuit board with large electrodes for soldering to the external pickup coil. The mutual inductances between the input coil and SQUID varied from 0.5 to 2.3 nH, depending on the number of turns of the input coil and the inductance of the SQUID. The SQUID modules with an external pickup coil made of normal metal showed a lower cut-off frequency of 45 Hz and a field noise as low as 35 fT Hz−1/2 (>4 kHz). (paper)

  10. Nano-sized SQUID-on-tip for scanning probe microscopy

    International Nuclear Information System (INIS)

    We present a SQUID of novel design, which is fabricated on the tip of a pulled quartz tube in a simple 3-step evaporation process without need for any additional processing, patterning, or lithography. The resulting devices have SQUID loops with typical diameters in the range 75–300 nm. They operate in magnetic fields up to 0.6 T and have flux sensitivity of 1.8 μΦ0/Hz1/2 and magnetic field sensitivity of 10−7 T/Hz1/2, which corresponds to a spin sensitivity of 65 μB/Hz1/2 for aluminum SQUIDs. The shape of the tip and the small area of the SQUID loop, together with its high sensitivity, make our device an excellent tool for scanning SQUID microscopy: With the SQUID-on-tip glued to a tine of a quartz tuning fork, we have succeeded in obtaining magnetic images of a patterned niobium film and of vortices in a superconducting film in a magnetic field.

  11. Some phenomena due to SQUID input properties when local feedback is present

    International Nuclear Information System (INIS)

    We have constructed a two-stage SQUID amplifier, in which series-mixing local feedback has been used to screen the SQUID input inductances and hence to boost the power gain of the amplifier. 2.9 pA/Hz1/2 current noise and 2.9 nH input inductance of the lower SQUID stage imply energy resolution of 18 times Planck constant at 4.2 K, which, arguably, can be further improved by input inductance screening. The upper stage consists of a 184-series 4-parallel SQUID array, which, when used alone, shows lower than 0.03 μΦ0/Hz2 flux noise, but which as a part of the two-stage amplifier is operated at a higher flux noise level to provide robust, EMI-tolerant output signal. The series-mixing feedback also facilitates negative SQUID input impedance, which would allow self-oscillating SQUID-based frequency domain multiplexing.

  12. Development of 2D Bi-SQUID Arrays with High Linearity

    CERN Document Server

    Berggren, S; Longhini, P; Palacios, A; Mukhanov, O A; de Escobar, A Leese; Taylor, B J; de Andrade, M C; Nisenoff, M; Fagaly, R L; Wong, T; Cho, E; Wong, E; In, V

    2013-01-01

    We develop a two-dimensional (2D) Superconducting Quantum Interference Filter (SQIF) array based on recently introduced high-linearity tri-junction bi-SQUIDs. Our bi-SQUID SQIF array design is based on a tight integration of individual bi- SQUID cells sharing inductances with adjacent cells. We provide extensive computer simulations, analysis and experimental measurements, in which we explore the phase dynamics and linearity of the array voltage response. The non-uniformity in inductances of the bi-SQUIDs produces a pronounced zero-field single antipeak in the voltage response. The anti-peak linearity and size can be optimized by varying the critical current of the additional junction of each bi-SQUID. The layout implementation of the tight 2D array integration leads to a distinct geometrical diamond shape formed by the merged dual bi-SQUID cells. Different size 2D arrays are fabricated using standard HYPRES niobium 4.5 kA/cm2 fabrication process. The measured linearity, power gain, and noise properties will ...

  13. Development of integrated SQUID measuring systems for application in magnetically unshielded environment. Final report; Entwicklung von stoerfeldunempfindlichen SQUID-Messanordnungen fuer den Einsatz in magnetisch gestoerter Umgebung. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Weber, P.; Warzemann, L.; Schambach, J.

    1998-01-27

    The development of SQUID measuring systems for using in magnetically unshielded environment is an important aim of cryoelectronics to find out new fields of application. The aim of this project was the development of suitable LTS-gradiometer structures which may be transferred also to HTS materials. Four different versions of LTS-SQUID-gradiometers with different requirements to the HTS technology have been developed and successfully tested in magnetically unshielded environment. The SQUID-sensors work stable in magnetic fields up to some mT and show a field gradient sensitivity of about 30 fT cm{sup -1} Hz{sup -1/2}. The balance of the gradiometer is some 10{sup -5}. Using the LTS-sensors measuring systems for susceptibility distributions and magnetrelaxometry (MRX) of magnetic nanoparticles have been tested. On the basis of these results an in-vivo measuring method for the application of MRX in medicine and biology will be developed. HTS-gradiometer-SQUIDs using results of this project have been produced. (orig.) [Deutsch] Ein wichtiges Ziel der Kryoelektronik ist die Entwicklung von SQUID-Messanordnungen fuer den Einsatz in magnetisch gestoerter Umgebung, um damit neue Anwendungsfelder zu erschliessen. Im Rahmen des Projektes waren hierfuer geeignete LTS-Gradiometer-SQUIDs zu entwickeln, die auch fuer die Umsetzung in HTS-Materialien geeignet sind. Dazu wurden die messtechnischen und technologischen Voraussetzungen geschaffen. Vier verschiedene Varianten von LTS-SQUID-Gradiometern mit unterschiedlichen Anforderungen an die spaetere Umsetzung in HTS-Technologie wurden realisiert und erfolgreich in magnetisch gestoerter Umgebung erprobt. Bei einer Empfindlichkeit von

  14. Influence of the tank circuit on the low frequency impedance of an rf-biased R-SQUID

    International Nuclear Information System (INIS)

    The dc -impedance of an rf-biased R-SQUID is studied analytically for the nonhysteretic regime. A mathematical analysis of the intrinsic behavior of an R-SQUID, including the mutual interaction between the tank circuit and the SQUID loop, is presented. The results obtained give good agreement with some experimentally observed features. Although the main aim of the present paper was to find an analytic solution for the dc -impedance of an R-SQUID, the results given here can also be used to estimate the R-SQUID parameters and to optimize the performance of a R-SQUID noise thermometer. The theory presented here also provides a good basis for modelling the noise properties of a Josephson junction noise thermometer

  15. Development of Magnetization Measurement Devices Using Micro-dc-SQUIDs and a Sr_2RuO_4 Microplate

    Science.gov (United States)

    Nago, Y.; Shinozaki, T.; Tsuchiya, S.; Ishiguro, R.; Kashiwaya, H.; Kashiwaya, S.; Nomura, S.; Kono, K.; Takayanagi, H.; Maeno, Y.

    2016-05-01

    We developed high-sensitivity magnetization measurement devices composed of micro-dc-SQUIDs and a superconducting Sr_2RuO_4 microplate, aiming to investigate novel magnetic properties related to a spin-triplet chiral p-wave superconductor with a mesoscopic size. Micron-sized dc-SQUID was fabricated by thin Al electrodes, and the SQUID structure was improved to prevent magnetic fluxes from intruding into SQUID electrodes. A Sr_2RuO_4 superconducting microplate was fabricated into the size as small as the SQUID loop using a focused ion beam and directly mounted on the SQUID with precise positioning for high-sensitivity magnetization measurements. In the preliminary magnetization measurements of this device, we observed vortices trapped into the plate and thus the lower critical field. The improved magnetization measurement device developed to exclude undesirable flux intrusion successfully enabled high-sensitivity detection of quantized vortex.

  16. Trophic relationships between the jumbo squid (Dosidicus gigas) and the lightfish (Vinciguerria lucetia) in the Humboldt Current System off Peru

    OpenAIRE

    Rosas-Luis, Rigoberto; Tafur-Jimenez, Ricardo; Alegre-Norza, Ana R.; Castillo-Valderrama, Pedro R.; Cornejo-Urbina, Rodolfo M.; Salinas-Zavala, Cesar A.; Sánchez, Pilar

    2011-01-01

    [EN] Acoustic surveys for assessing the biomass and distribution of the jumbo squid (Dosidicus gigas) and the lightfish (Vinciguerria lucetia) were carried out in the Humboldt Current System of Peru in 2007 and 2008. At the same time, 937 jumbo squid were caught and their stomach contents analyzed. The diet of the jumbo squid was dominated by mesopelagic fish. The first component of their fish diet was V. lucetia and the second component was the myctophid fish Diogenichthys laternatus. Acoust...

  17. Valorization of chitosan from squid pens and further use on the development of scaffolds for biomedical applications

    OpenAIRE

    Reys, L. L.; S.S. Silva; Oliveira, Joaquim M.; Frias, A. M.; Mano, J. F.; Silva, Tiago H.; Reis, R. L.

    2012-01-01

    Objectives: The aim of the present work is the valorization of squid pens through the production of chitosan that can be used for the development of biomedical applications. The present work is focused on !-chitin extraction from squid pens of the species Dosidicus gigas and its further conversion into chitosan. The biomedical potential of the isolated squid chitosan was assessed by processing this polymer as scaffolds for tissue engineering strategies. Methods: Alkali solut...

  18. Influence of inductance induced noise in an YBa2Cu3O7 dc-SQUID at high operation temperatures

    DEFF Research Database (Denmark)

    Nilsson, P. Å.; Claeson, T.; Hansen, J. B.; Kyhle, Anders

    1994-01-01

    The voltage modulation depth of a high T(c) dc-SQUID was measured at temperatures close to T(c) and compared to a model by Enpuku et al. where the flux noise from the SQUID inductance is taken into account. The device was an YBa2Cu3O7 dc-SQUID made on a bicrystal substrate of SrTiO3. The design was...

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

    Science.gov (United States)

    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. PMID:18345820

  20. Investigation of dc-SQUID dynamics by multiple flux entry

    International Nuclear Information System (INIS)

    Digital Josephson circuits that do not switch into the voltage state provide an opportunity for high speed signal processing. Fast SFQ (Single Flux Quantum) logic devices must record and process small fast pulses generated by single fluxoid events. An useful application in cryoelectronics is an analog-to-digital converter using the intrinsic flux quantization of closed superconducting structures. The analog signal is quantized and converted into a pulse train resulting from fluxoid transitions. The dynamics of multiple flux entry from these transitions was analyzed for a dc-SQUID structure as quantizer proposed by Phillips in view of high-Tc applications(1,2). The device performance of a incremental quantizer depending on various circuit parameters was explored by numerical simulations based on the Stewart-McCumber model of the Josephson junction. We found several conditions which must be satisfied for an unambiguously pulse train, from which the analog signal can be faithfully reconstructed. The results of the simulations are presented illustrating the various ways in which the pulse trains are affected. (orig.)

  1. Sodium movements in perfused squid giant axons. Passive fluxes.

    Science.gov (United States)

    Rojas, E; Canessa-Fischer, M

    1968-08-01

    Sodium movements in internally perfused giant axons from the squid Dosidicus gigas were studied with varying internal sodium concentrations and with fluoride as the internal anion. It was found that as the internal concentration of sodium was increased from 2 to 200 mM the resting sodium efflux increased from 0.09 to 34.0 pmoles/cm(2)sec and the average resting sodium influx increased from 42.9 to 64.5 pmoles/cm(2)sec but this last change was not statistically significant. When perfusing with a mixture of 500 mM K glutamate and 100 mM Na glutamate the resting efflux was 10 +/- 3 pmoles/cm(2)sec and 41 +/- 10 pmoles/cm(2)sec for sodium influx. Increasing the internal sodium concentration also increased both the extra influx and the extra efflux of sodium due to impulse propagation. At any given internal sodium concentration the net extra influx was about 5 pmoles/cm(2)impulse. This finding supports the notion that the inward current generated in a propagated action potential can be completely accounted for by movements of sodium. PMID:5672003

  2. Jumbo squid beaks: inspiration for design of robust organic composites.

    Science.gov (United States)

    Miserez, Ali; Li, Youli; Waite, J Herbert; Zok, Frank

    2007-01-01

    The hard tissues found in some invertebrate marine organisms represent intriguing paradigms for robust, lightweight materials. The present study focuses on one such tissue: that comprising the beak of the jumbo squid (Dosidicus gigas). Its main constituents are chitin fibers (15-20wt.%) and histidine- and glycine-rich proteins (40-45%). Notably absent are mineral phases, metals and halogens. Despite being fully organic, beak hardness and stiffness are at least twice those of the most competitive synthetic organic materials (notably engineering polymers) and comparable to those of Glycera and Nereis jaws. Furthermore, the combination of hardness and stiffness makes the beaks more resistant to plastic deformation when in contact with blunt abrasives than virtually all metals and polymers. The 3,4-dihydroxy-l-phenylalanine and abundant histidine content in the beak proteins as well as the pigmented hydrolysis-resistant residue are suggestive of aromatic cross-linking. A high cross-linking density between the proteins and chitin may be the single most important determinant of hardness and stiffness in the beak. Beak microstructure is characterized by a lamellar arrangement of the constituents, with a weak interface that promotes crack deflection and endows the structure with high fracture toughness. The susceptibility of this microstructure to cracking along these interfaces from contact stresses at the external surface is mitigated by the presence of a protective coating. PMID:17113369

  3. Optimization of the R-SQUID noise thermometer

    International Nuclear Information System (INIS)

    The Josephson junction can be used to convert voltage into frequency and thus it can be used to convert voltage fluctuations generated by Johnson noise in a resistor into frequency fluctuations. As a consequence, the temperature of the resistor can be defined by measuring the variance of the frequency fluctuations. Unfortunately, the absolute determination of temperature by this approach is disturbed by several undesirable effects: a rolloff introduced by the bandwidth of the postdetection filter, additional noise caused by rf amplifiers, and a mixed noise effect caused by the nonlinearity of the Josephson junction together with rf noise in the tank circuit. Furthermore, the variance is a statistical quantity and therefore the limited number of frequency counts produces inaccuracy in a temperature measurement. In this work the total inaccuracy of the noise thermometer is analyzed and the optimal choice of the parameters is derived. A practical way to find the optimal conditions for the Josephson junction noise thermometer is discussed. The inspection shows that under the optimal conditions the total error is dependent only on the temperature under determination, the equivalent noise temperature of the preamplifier, the bias frequency of the SQUID, and the total time used for the measurement

  4. Metabolic efficiency with fast spiking in the squid axon

    Directory of Open Access Journals (Sweden)

    Abdelmalik Moujahid

    2012-11-01

    Full Text Available Fundamentally, action potentials in the squid axon are consequence of the entrance of sodium ions during the depolarization of the rising phase of the spike mediated by the outflow of potassium ions during the hyperpolarization of the falling phase. Perfect metabolic efficiency with a minimum charge needed for the change in voltage during the action potential would confine sodium entry to the rising phase and potassium efflux to the falling phase. However, because sodium channels remain open to a significant extent during the falling phase, a certain overlap of inward and outward currents is observed. In this work we investigate the impact of ion overlap on the number of the adenosine triphosphate (ATP molecules and energy cost required per action potential as a function of the temperature in a Hodgkin-Huxley model. Based on a recent approach to computing the energy cost of neuronal AP generation not based on ion counting, we show that increased firing frequencies induced by higher temperatures imply more efficient use of sodium entry, and then a decrease in the metabolic energy cost required to restore the concentration gradients after an action potential. Also, we determine values of sodium conductance at which the hydrolysis efficiency presents a clear minimum.

  5. Squid pen chitin chitooligomers as food colorants absorbers.

    Science.gov (United States)

    Liang, Tzu-Wen; Huang, Chih-Ting; Dzung, Nguyen Anh; Wang, San-Lang

    2015-01-01

    One of the most promising applications of chitosanase is the conversion of chitinous biowaste into bioactive chitooligomers (COS). TKU033 chitosanase was induced from squid pen powder (SPP)-containing Bacillus cereus TKU033 medium and purified by ammonium sulfate precipitation and column chromatography. The enzyme was relatively more thermostable in the presence of the substrate and had an activity of 93% at 50 °C in a pH 5 buffer solution for 60 min. Furthermore, the enzyme used for the COS preparation was also studied. The enzyme products revealed various mixtures of COS that with different degrees of polymerization (DP), ranging from three to nine. In the culture medium, the fermented SPP was recovered, and it displayed a better adsorption rate (up to 96%) for the disperse dyes than the water-soluble food colorants, Allura Red AC (R40) and Tartrazne (Y4). Fourier transform-infrared spectroscopic (FT-IR) analysis proved that the adsorption of the dyes onto fermented SPP was a physical adsorption. Results also showed that fermented SPP was a favorable adsorber and could be employed as low-cost alternative for dye removal in wastewater treatment. PMID:25608726

  6. Six steps in quality intervention development (6SQuID).

    Science.gov (United States)

    Wight, Daniel; Wimbush, Erica; Jepson, Ruth; Doi, Lawrence

    2016-05-01

    Improving the effectiveness of public health interventions relies as much on the attention paid to their design and feasibility as to their evaluation. Yet, compared to the vast literature on how to evaluate interventions, there is little to guide researchers or practitioners on how best to develop such interventions in practical, logical, evidence based ways to maximise likely effectiveness. Existing models for the development of public health interventions tend to have a strong social-psychological, individual behaviour change orientation and some take years to implement. This paper presents a pragmatic guide to six essential Steps for Quality Intervention Development (6SQuID). The focus is on public health interventions but the model should have wider applicability. Once a problem has been identified as needing intervention, the process of designing an intervention can be broken down into six crucial steps: (1) defining and understanding the problem and its causes; (2) identifying which causal or contextual factors are modifiable: which have the greatest scope for change and who would benefit most; (3) deciding on the mechanisms of change; (4) clarifying how these will be delivered; (5) testing and adapting the intervention; and (6) collecting sufficient evidence of effectiveness to proceed to a rigorous evaluation. If each of these steps is carefully addressed, better use will be made of scarce public resources by avoiding the costly evaluation, or implementation, of unpromising interventions. PMID:26573236

  7. Squid Pen Chitin Chitooligomers as Food Colorants Absorbers

    Directory of Open Access Journals (Sweden)

    Tzu-Wen Liang

    2015-01-01

    Full Text Available One of the most promising applications of chitosanase is the conversion of chitinous biowaste into bioactive chitooligomers (COS. TKU033 chitosanase was induced from squid pen powder (SPP-containing Bacillus cereus TKU033 medium and purified by ammonium sulfate precipitation and column chromatography. The enzyme was relatively more thermostable in the presence of the substrate and had an activity of 93% at 50 °C in a pH 5 buffer solution for 60 min. Furthermore, the enzyme used for the COS preparation was also studied. The enzyme products revealed various mixtures of COS that with different degrees of polymerization (DP, ranging from three to nine. In the culture medium, the fermented SPP was recovered, and it displayed a better adsorption rate (up to 96% for the disperse dyes than the water-soluble food colorants, Allura Red AC (R40 and Tartrazne (Y4. Fourier transform-infrared spectroscopic (FT-IR analysis proved that the adsorption of the dyes onto fermented SPP was a physical adsorption. Results also showed that fermented SPP was a favorable adsorber and could be employed as low-cost alternative for dye removal in wastewater treatment.

  8. Mobile HTS-SQUID NDE system with robot arm and active shielding using fluxgate

    International Nuclear Information System (INIS)

    A robot-arm-based mobile HTS-SQUID NDE system was developed for inspection of advanced structures such as hydrogen fuel cell tanks. In order to realize stable operation of HTS-SQUID exposed in Earth's field and robot arm's noise without flux trapping, flux jumping and unlocking during motion, a new active magnetic shielding (AMS) technique using fluxgate was introduced. The high sensitive fluxgate, which could measure magnetic field of up to several 10 μT, was mounted near an HTS-SQUID gradiometer on the robot arm to measure the ambient noise and feed back its output to a compensation coil, which surrounded both SQUID and fluxgate to cancel the ambient noise around them. The AMS technique successfully enabled the HTS-SQUID gradiometer to be moved at 10 mm/s by the robot arm in unshielded environment without flux trapping, jumping and unlocking. Detection of hidden slots in multi-layer composite-metal structures imitating the fuel cell tank was demonstrated

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

    Science.gov (United States)

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

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

  10. Partial characterization of an effluent produced by cooking of Jumbo squid (Dosidicus gigas) mantle muscle.

    Science.gov (United States)

    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. PMID:19748263

  11. Vestigial phragmocone in the gladius points to a deepwater origin of squid (Mollusca: Cephalopoda)

    Science.gov (United States)

    Arkhipkin, Alexander I.; Bizikov, Vyacheslav A.; Fuchs, Dirk

    2012-03-01

    The microstructure of the gladius cone was investigated in six species of nektonic squid: shallow-water Loligo gahi (Loliginidae), pelagic eurybathic Illex argentinus, Todarodes pacificus, Dosidicus gigas (Ommastrephidae), and deepwater Onykia ingens (Onychoteuthidae) and Gonatus antarcticus (Gonatidae) using state-of-the-art microscopy. Apart from L. gahi, all other species had septa-like layers in the gladius cone, which for the first time were investigated in detail and compared with those in extinct Cretaceous belemnites Hibolithes sp. and Pachyteuthis sp., and spirulid Cyrtobelus sp. It was found that the organic layers of the gladius cone in recent squid can be homologized with the organic components of the shell in fossil phragmocone-bearing coleoids. The septa-like layers in modern gladius cones therefore represent a vestigial phragmocone composed of organic septal rudiments of the ancestral phragmocone that has lost the siphuncle and gas-filled chambers. The well-developed rostrum in onychoteuthids and small rostrum of the gladius in ommastrephids and gonatids can be seen as homologous with the belemnoid rostrum, which may indicate a close phylogenetic relationship between belemnites and at least some squid. Possible evolutionary pathways of the reduction of the functional phragmocone in squid ancestors are discussed. Several features such as the loss of shell calcification, deep water speciation, and the structure of the equilibrium organ point to a deep-water origin of squids.

  12. Behavioral ecology of jumbo squid (Dosidicus gigas) in relation to oxygen minimum zones

    Science.gov (United States)

    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.

  13. Closed-cycle cryocooled SQUID system with superconductive shield for biomagnetism

    International Nuclear Information System (INIS)

    We developed a cryocooled SQUID system with which human magnetocardiogram (MCG) and possibly magnetoenceparogram (MEG) can be measured. To reduce cyclic magnetic noises originating from the regenerator of the cold heads of the cryocooler, a superconductive shield (99.5% Pb) was used to protect the SQUID sensors, and a ferromagnetic shield (78% Ni alloy) was used to screen the cold head. In addition, the SQUID sensors’ chamber was placed at a distance of 1.8 m from the cold head chamber to install the cold-head chamber outside the magnetically shielded room (MSR) for future development. The loss in cooling power due to the increased distance was compensated by increasing the number of thermal rods, and thus the SQUID sensor and superconductive shield could be refrigerated to 4.8 K and 5 K, respectively. The superconductive shield successfully rejected thermal noise emitted from metallic blocks used to improve thermal conduction. The noise of the SQUID system was 3 fT/Hz1/2, and the cyclic magnetic noise could be reduced to 1.7 pT. We could obtain a clear MCG signal while the entire cryogenics was in operation without any special digital processing. (paper)

  14. MRX measurement setup employing a directly-coupled high-Tc SQUID with slotted pickup loop

    International Nuclear Information System (INIS)

    Magnetic nanoparticles (MNP) are employed in a wide range of medical and industrial applications. Besides other characterization techniques, magnetorelaxometry (MRX) is well established. In our MRX setup, we employ a directly-coupled high-Tc SQUID with a slotted pickup loop as magnetic field sensor. The whole setup is installed in a magnetically shielded room. The MNP sample, which is attached to a glass dipstick containing the SQUID, is magnetized by a pair of Helmholtz-coils. In order to prevent flux vortices from entering the SQUID, the sensor is aligned parallel to the magnetizing field so that only the stray field of the MNP is measured. The aligning process is accomplished by using three alignment screws. Hence, the SQUID only measures 1 ppm of the magnetizing field which is in the order of several mT. Since the magnetic nanoparticles are placed in liquid nitrogen, the relaxation time constant increases in comparison to a measurement of the particles at room temperature allowing to investigate particle sizes down to 10 nm. Here, we present our MRX setup and the employed SQUID design. We evaluate its performance by carrying out MRX measurements on immobilized MNPs.

  15. SQUID-based setup for the absolute measurement of the Earth’s magnetic field

    International Nuclear Information System (INIS)

    We present a configuration of LTS dc SQUID magnetometers that is suited for an absolute measurement of the vector components of the Earth’s magnetic field with a white noise level of about 6 fT Hz−1/2. Due to its periodic voltage–flux characteristic, a SQUID’s output voltage generally corresponds to a set of equidistant fluxes or magnetic field strengths. To resolve this ambiguity, we introduce a configuration of coplanar SQUIDs integrated on a single chip, which exhibit effective areas differing by several orders of magnitude. The set of possible magnetic field strengths matching the output voltages of these SQUIDs is thereby significantly reduced and especially unique for magnetic field strengths less than a certain threshold value of about 10 μT in our current implementation. The SQUIDs are realized with 0.8 μm cross-type Josephson junctions that withstand high background fields of up to 3.9 mT during cool down and operation. A first one-dimensional experimental implementation successfully measured the modulation of the magnetic field component perpendicular to the sensor surface with amplitudes exceeding 50 μT. The overall dynamic range of the SQUID magnetometer system achieves 190 dB. (paper)

  16. Dynamic behavior of dc SQUIDs in time-division multiplexing readout schemes

    International Nuclear Information System (INIS)

    We have investigated the transient response of superconducting quantum interference devices (SQUIDs) used in time-division multiplexing schemes for the readout from arrays of superconducting transition-edge sensors (TES). In time-division multiplexing the per channel settling time is an important parameter since it limits the multiplexing frequency as well as the signal-to-noise ratio. Although SQUIDs in general are fast cryoelectronic devices operating at a nanosecond scale, experimental evidence shows that the settling time in bias-switched SQUID multiplexers can, in the case of a low impedance input circuit, reach several microseconds. We have confirmed this behavior through numerical transient analysis using a Josephson circuit simulator. Within the simulation we have found that the transient response can be reduced using an extra inductor in series with the input coil of the dc SQUID. This result in turn has been confirmed experimentally. We furthermore discuss the conflicting constraints that a desired high signal bandwidth places on the parameters of the multiplexer, the readout SQUIDs, and the TES. (paper)

  17. 76 FR 3044 - Fisheries of the Exclusive Economic Zone Off Alaska; Sculpins, Sharks, Squid, and Octopus in the...

    Science.gov (United States)

    2011-01-19

    ... harvest specifications for groundfish of the GOA (75 FR 11749, March 12, 2010). In accordance with Sec... Economic Zone Off Alaska; Sculpins, Sharks, Squid, and Octopus in the Gulf of Alaska AGENCY: National...: Temporary rule; closure. SUMMARY: NMFS is prohibiting directed fishing for sculpins, sharks, squid,...

  18. Nb-based integrated SQUID gradiometer without flux transformer as a prototype for high-Tc device

    International Nuclear Information System (INIS)

    It is well known, that the devices based on Josephson junctions (i.e. SQUIDs) are most sensitive for magnetic measurements. The application of high-Tc superconductors for SQUID magnetometers is connected with some problems, while the main problems are the large thermal fluctuations due to a high operating temperature and technological difficulties of fabrication of multilayer thin film structures. (orig.)

  19. A SQUID biomagnetometer system for measurement of a human cervical spinal cord evoked field

    International Nuclear Information System (INIS)

    We developed a SQUID biomagnetometer system for detecting the magnetic signals evoked from the human cervix within the scope of non-invasive diagnosis of the function of the cervical spinal cord. The system has two main particular features. One is vector SQUID gradiometers and the other is a cryostat optimized for a reclining subject. The vector SQUID gradiometers can maximize the magnetic information acquired from the limited observation area around the neck and the shape of the new cryostat enables a subject to keep his/her position stably in a relaxed manner during the measurement. As a result, we successfully recorded the evoked magnetic fields corresponding to the neural signal travelling along the spinal cords from the necks of human subjects who were given electric stimuli to their thoracic spinal cords

  20. A high-Tc flip-chip SQUID gradiometer for mobile underwater magnetic sensing

    International Nuclear Information System (INIS)

    We report on the development of a magnetic gradient tensor sensor based on high- Tc SQUIDs for marine surveying applications. The proposed system uses six planar gradiometers incorporated into a hexagonal pyramid structure where the combined output will provide a measure of the gradient tensor. This report focuses on the development and characterization of long baseline high- Tc SQUID gradiometers for this purpose. We compare the performance of two separate fabricated gradiometer designs. These devices both consist of a large 40 mm x 20 mm gradiometric pickup loop antenna flip-chip coupled to a small readout SQUID gradiometer. We have thus far demonstrated an unshielded gradient sensitivity of ∼29 fT cm-1 Hz-1/2 at 1 kHz and ∼170 fT cm-1 Hz-1/2 at 10 Hz through optimizing the coupling inductances of our device.

  1. A SQUID biomagnetometer system for measurement of a human cervical spinal cord evoked field

    Energy Technology Data Exchange (ETDEWEB)

    Adachi, Y [Applied Electronics Laboratory, Kanazawa Institute of Technology, 3 Amaike, Kanazawa, Ishikawa 920-1331 (Japan); Kawai, J [Applied Electronics Laboratory, Kanazawa Institute of Technology, 3 Amaike, Kanazawa, Ishikawa 920-1331 (Japan); Uehara, G [Applied Electronics Laboratory, Kanazawa Institute of Technology, 3 Amaike, Kanazawa, Ishikawa 920-1331 (Japan); Ogata, H [Applied Electronics Laboratory, Kanazawa Institute of Technology, 3 Amaike, Kanazawa, Ishikawa 920-1331 (Japan); Miyamoto, M [Applied Electronics Laboratory, Kanazawa Institute of Technology, 3 Amaike, Kanazawa, Ishikawa 920-1331 (Japan); Kawabata, S [Department of Orthopaedic Surgery, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8519 (Japan); Tomizawa, S [Department of Orthopaedic Surgery, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8519 (Japan)

    2005-12-15

    We developed a SQUID biomagnetometer system for detecting the magnetic signals evoked from the human cervix within the scope of non-invasive diagnosis of the function of the cervical spinal cord. The system has two main particular features. One is vector SQUID gradiometers and the other is a cryostat optimized for a reclining subject. The vector SQUID gradiometers can maximize the magnetic information acquired from the limited observation area around the neck and the shape of the new cryostat enables a subject to keep his/her position stably in a relaxed manner during the measurement. As a result, we successfully recorded the evoked magnetic fields corresponding to the neural signal travelling along the spinal cords from the necks of human subjects who were given electric stimuli to their thoracic spinal cords.

  2. Slow swimming, fast strikes: effects of feeding behavior on scaling of anaerobic metabolism in epipelagic squid.

    Science.gov (United States)

    Trueblood, Lloyd A; Seibel, Brad A

    2014-08-01

    Many pelagic fishes engage prey at high speeds supported by high metabolic rates and anaerobic metabolic capacity. Epipelagic squids are reported to have among the highest metabolic rates in the oceans as a result of demanding foraging strategies and the use of jet propulsion, which is inherently inefficient. This study examined enzymatic proxies of anaerobic metabolism in two species of pelagic squid, Dosidicus gigas and Doryteuthis pealeii (Lesueur 1821), over a size range of six orders of magnitude. We hypothesized that activity of the anaerobically poised enzymes would be high and increase with size as in ecologically similar fishes. In contrast, we demonstrate that anaerobic metabolic capacity in these organisms scales negatively with body mass. We explored several cephalopod-specific traits, such as the use of tentacles to capture prey, body morphology and reduced relative prey size of adult squids, that may create a diminished reliance on anaerobically fueled burst activity during prey capture in large animals. PMID:25079893

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

    Science.gov (United States)

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

    2014-05-01

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

  4. The jumbo squid, Dosidicus gigas (Ommastrephidae), living in oxygen minimum zones II: Blood-oxygen binding

    Science.gov (United States)

    Seibel, Brad A.

    2013-10-01

    Dosidicus gigas is a large, metabolically active squid that migrates across a strong oxygen and temperature gradient in the Eastern Pacific. Here we analyze the oxygen-binding properties of the squid's respiratory protein (hemocyanin, Hc) that facilitate such activity. A high Hc-oxygen affinity, strong temperature dependence, and pronounced pH sensitivity (P50=0.009T2.03, pH 7.4; Bohr coefficient=ΔlogP50/ΔpH=-1.55+0.034T) of oxygen binding facilitate night-time foraging in the upper water column, and support suppressed oxygen demand in hypoxic waters at greater depths. Expanding hypoxia may act to alter the species habitable depth range. This analysis supports the contention that ocean acidification could limit oxygen carrying capacity in squids at warmer temperature leading to reduced activity levels or altered distribution.

  5. [Determination of proximal chemical composition of squid (dosidicus gigas) and development of gel products].

    Science.gov (United States)

    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. PMID:10488395

  6. A post-SQUID ac amplifier aimed for multiplexed detector readouts

    International Nuclear Information System (INIS)

    We have built a room temperature amplifier based on Si JFETs (junction field effect transistors) intended for ac-coupled SQUID (superconducting quantum interference device) readouts, such as in frequency-domain multiplexed transition-edge sensor systems. The amplifier operates at 5 MHz centre frequency where it has the measured noise temperature of 27 K for a 60 Ω load, which includes the noise from the active termination and the room temperature transformer. When it was driven from a SQUID with an on-chip matching transformer, flux noise of 0.45 μΦ0 Hz-1/2 was obtained. Additionally, we consider the potential of the recently introduced SiGe bipolar transistors for the same application. The dynamic range considerations for SQUID multiplexers, which require the use of an amplifier with a low noise temperature, are briefly discussed

  7. Properties of the microwave SQUID with an YBaCuO point contact junction

    International Nuclear Information System (INIS)

    A high sensitivity microwave SQUID, suitable for rf attenuation measurements, is constructed by taking advantage of the low density of states of current carriers in high-T/sub c/ materials. In this article the dynamics, the noise properties and the sensitivity of the microwave SQUID are theoretically analyzed. The ultimate energy resolution of the waveguide SQUID is inversely proportional to the characteristic frequency ω/sub c/ = R/sub q//L of the loop. ω/sub c/ is high for YBaCuO junctions at 4.2 K because of small leakage. A flux sensitivity of 4 x 10/sup -6/ PHI/sub o//√Hz has been achieved, which is in good agreement with the theoretical predictions

  8. A signal-to-noise chart for designing planar high-Tc SQUID gradiometers for magnetocardiographs

    International Nuclear Information System (INIS)

    To design practical planar high-Tc SQUID gradiometers for magnetocardiographs, a signal-to-noise (S/N) chart that will enable the gradiometers to detect P-waves was developed. The signal was estimated as the gradient field generated by the mean current dipole of P-waves of 20 healthy volunteers. The current dipoles were obtained by using a conventional magnetocardiograph comprising low-Tc SQUID gradiometers. On the other hand, the noise was estimated from studies on previously reported gradiometers based on the limit of intrinsic gradient field noise. The obtained S/N chart indicates that a gradiometer with a baseline longer than 12 mm is necessary for detecting P-waves without averaging. The reliability of the S/N chart was confirmed by detecting actual P-waves with 100-beat averaging by using a fabricated planar high-Tc SQUID gradiometer with a baseline of 6.75 mm. (author)

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

    International Nuclear Information System (INIS)

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

  10. A SQUID magnetometry system for a cryogenic neutron electric dipole moment experiment

    International Nuclear Information System (INIS)

    Precision magnetometry is an essential component of any neutron electric dipole moment experiment in order to correct shifts in the neutron precession frequency due to changes in the magnetic field. We have developed a magnetometry system using 12 SQUID sensors, designed to operate in 0.5 K superfluid helium. The pick-up loops located near the neutron cell are connected to the SQUID sensors by ∼2 m twisted wire pairs. The SQUID readout cables are run via an intermediate stage at 4.2 K. The system has been installed and tested in the cryoEDM apparatus at the ILL, Grenoble, and used to characterise the magnetic environment. Further tests in a suitable low noise environment confirm it meets our requirements

  11. A simple SQUID system with one operational amplifier as readout electronics

    International Nuclear Information System (INIS)

    We describe a dc Superconducting Quantum Interference Device (SQUID) readout electronics in Flux Locked Loop (FLL) mode without integrator and with only one operational amplifier, which is called Single Chip Readout Electronics (SCRE). A weakly damped niobium-SQUID magnetometer with a large flux-to-voltage transfer coefficient of about ∂V/∂Φ ≈ 380 μV/Φ0 and SCRE results in a very simple SQUID system. We characterize the system and demonstrate its applicability to Magnetocardiography (MCG) and measurements using the Transient ElectroMagnetic (TEM) method. SCRE not only simplifies the readout scheme, but also improves the system stability, the bandwidth and the slew rate. The difference between SCRE and a conventional readout scheme (preamplifier + amplifier + integrator) is also discussed. (paper)

  12. HTSC-RF-SQUID sensors in magnetic fields: Characterisation and noise reduction

    International Nuclear Information System (INIS)

    Due to their excellent sensitivity to magnetic fields, HTS SQUID sensors are widely used in many applications outside magnetic shielding, e.g. for geophysical exploration of ore and hydrocarbon deposits, for nondestructive evaluation of aircraft and bridge components and for the measurement of biomagnetic signals for diagnostic purposes. In this work, two main subjects are investigated which are essential for the realisation of highly sensitive SQUID systems for operation in a magnetically strongly disturbed environment, for example for application in magnetocardiography: the influence of magnetic fields on the operation of YBa2Cu3O7-δ-rf-washer-SQUIDs with step-edge Josephson junctions is investigated (section 3) and a method for the reduction of environmental magnetic noise is presented and characterised (section 4). (orig.)

  13. Detection of small cracks using high-Tc SQUIDs in an unshielded environment

    International Nuclear Information System (INIS)

    In this study, we utilized high-Tc rf SQUIDs to detect microcracks in metallic samples in an unshielded environment. The environmental noise in the SQUID was suppressed by using a first-order electronic gradiometer. The samples under investigation were excited by ac magnetic fields applied by a differential excitation coil. A technique utilizing the differential defect field was adopted to analyse the defect field from the crack. It was found that the crack is detectable for the crack width down to micrometres. In addition, the defect field is not a function of the crack width when it is much less than the size of the excitation coil. Finally, the SQUID nondestructive evaluation (NDE) system that was built was also applied to detect small cracks due to fatigue. (author)

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

    Science.gov (United States)

    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.

  15. Grain boundary high-Tc dc-SQUIDs with self-organized nanocrystals

    International Nuclear Information System (INIS)

    We fabricated and investigated direct current superconducting quantum interference devices (dc-SQUIDs) based on YBa2Cu3O7-x (YBCO) grain boundary Josephson junctions. Directed embedding of gold nanoparticles different sizes can modify the crystalline structure and thus the superconducting properties of the YBCO thin films and grain boundaries. We investigated the growth conditions of these particles as well as their influence on the properties of the YBCO thin films. The variation of the size and distribution of the gold nanoparticles changes the electrical properties of the dc-SQUIDs. For this kind of device the normal resistance, critical current density, the resulting IcRN-product, the London penetration depth and transfer function are analyzed. Furthermore we show noise properties for such modified dc-SQUIDs.

  16. Quantum State Engineering with the rf-SQUID: A Brief Introduction

    CERN Document Server

    Altman, C

    2003-01-01

    Quantum computers take advantage of the superpositional logic of quantum mechanics to allow for dramatic increases in computational efficiency. rf-SQUIDs show potential for quantum computing applications by forming the qubit component of a quantum computer, through simply treating the direction of current - clockwise or counterclockwise - as the value of the bit. rf-SQUIDs present a major advantage over atomic-scale qubit systems - they are sensitive to parameters that can be engineered. Flux qubits are linked through controlled inductive coupling: the magnetic field of each junction affects the others. The strength of this coupling can be 'tuned,' allowing for refined control over the behaviour of the system. rf-SQUIDs can also be mass produced on-chip, making large-scale production feasible.

  17. Superconducting Analogues of Quantum Optical Phenomena: Schrodinger Cat States and Squeezing in a SQUID Ring

    CERN Document Server

    Everitt, M J; Stiffell, P B; Prance, R J; Prance, H; Vourdas, A; Ralph, J F

    2004-01-01

    In this paper we explore the quantum behaviour of a SQUID ring which has a very strong Josephson coupling energy. We show that that the eigenfunctions of the Hamiltonian for the ring can be used to create Schrodinger cat states. We also show that the ring potential may be utilised to squeeze coherent states. With the SQUID ring as a strong contender as a device for manipulating quantum information, such properties may be of great utility in the future. However, as with all candidate systems for quantum technologies, decoherence is a fundamental problem. In this paper we apply an open systems approach to model the effect of coupling a quantum mechanical SQUID ring to a thermal bath. We use this model to demonstrate the manner in which decoherence affects the quantum states of the ring.

  18. A 64-channel whole-head SQUID system in a superconducting magnetic shield

    International Nuclear Information System (INIS)

    A superconducting magnetic shield of high-Tc superconductor Bi(Pb)-Sr-Ca-Cu-Ox has been constructed whose diameter is 65 cm and length is 160 cm. We have successfully observed magnetic fields from somatosensory-evoked human brains in the superconducting magnetic shield by stimulating the median nerves of patients by current pulses. We made a 64-channel whole-head SQUID magnetometer of superconductor/normal metal/superconductor (SNS) junctions which do not show low-frequency telegraph noise. The sensitivities of the dc SQUID mesoscopic SNS junctions are around 5 fT Hz-1/2 even in rather unfavourable surroundings. The magnetic shield can reduce a magnetic field by around -80 dB or a factor of 10-4 even at as low a frequency as 0.05 Hz. Therefore SQUIDs of SNS junctions and a superconducting magnetic shield are a good combination. (author)

  19. Monitoring geomagnetic signals of groundwater movement using multiple underground SQUID magnetometers

    Directory of Open Access Journals (Sweden)

    Henry S.

    2014-01-01

    Full Text Available Groundwater can influence the geomagnetic field measured underground in at least two key ways. The water levels in rock will determine its electrical conductivity, and thus change the magnitude of the telluric currents induced in the rock by changing magnetic fields generated in the ionosphere. This can be studied by using multiple magnetometers at different underground locations. Secondly the flow of water through rock will generate a small magnetic signal, of unknown magnitude, through the electrokinetic effect. SQUID magnetometry has the potential to allow passive studies of groundwater changes in complex systems such as karst. We have monitored geomagnetic signals using two SQUID magnetometers at the LSBB underground laboratory, and set an initial limit on the magnitude of the electrokinetic signal. We now plan to carry out a longer term measurement using three SQUID systems as well as fluxgate sensors to track changes in the gradient of the magnetic field across the underground complex.

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

    Science.gov (United States)

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

    1995-01-01

    A SQUID is the most sensitive device to detect change in magnetic field. A nondestructive testing (NDT) device using high temperature SQUID's and eddy current method will be much more sensitive than those currently used eddy current systems, yet much cheaper than one with low temperature SQUID's. In this paper, we present our study of such a NDT device using a high temperature superconducting rf-SQUID as a gradiometer sensor. The result clearly demonstrates the expected sensitivity of the system, and indicates the feasibility of building a portable HTS SQUID NDT device with the help from cryocooler industry. Such a NDT device will have a significant impact on metal corrosion or crack detection technology.

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

    Energy Technology Data Exchange (ETDEWEB)

    Lu, D.F.; Fan, C.; Ruan, J.Z. [Midwest Superconductivity Inc., Lawrence, KS (United States)] [and others

    1994-12-31

    A SQUID is the most sensitive device to detect change in magnetic field. A non-destructive testing (NDT) device using high temperature SQUIDs and eddy current method will be much more sensitive than those currently used eddy current systems, yet much cheaper than one with low temperature SQUIDs. In this paper, we present our study of such a NDT device using a high temperature superconducting rf-SQUID as a gradiometer sensor. The result clearly demonstrates the expected sensitivity of the system, and indicates the feasibility of building a portable HTS SQUID NDT device with the help from cryocooler industry. Such a NDT device will have a significant impact on metal corrosion or crack detection technology.

  2. Comprehensive model of Jumbo squid Dosidicus gigas trophic ecology in the Northern Humboldt current system.

    Science.gov (United States)

    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

  3. Comprehensive model of Jumbo squid Dosidicus gigas trophic ecology in the Northern Humboldt current system.

    Directory of Open Access Journals (Sweden)

    Ana Alegre

    Full Text Available 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.

  4. Development of a highly sensitive beam current monitor with a SQUID and superconducting magnetic shield

    International Nuclear Information System (INIS)

    Beam diagnostics are an essential constituent of any accelerator. There are a large variety of beam parameters, and total current is one of the most important parameters for accelerators. A current monitor is used to operate an accelerator efficiently and to improve the performance of the machine. A Faraday cup is the most fundamental current detection process, in which charged particles are stopped in the cup. However, this destructive method cannot be applied for high-current or high-energy beams because the total energy carried by the beam can destroy and activate the intercepting material. Therefore, non-destructive beam current measurement requires the use of current transformers that detect the magnetic field produced by the pulsed or DC beam. On the other hand, a new type of beam current monitor using a low-temperature superconducting (LTS) magnetic shield and an LTS SQUID was developed to measure the faint ion beams that are below the lowest measurable limit of the DC current transformer (DCCT) for atomic-physics studies. Recently, a prototype of a highly sensitive SQUID current monitor for measuring the intensity of faint beams, such as radioisotope beams, was completed for the RIKEN RI beam factory. This monitor is composed of a high-temperature superconducting (HTS) magnetic shield and an HTS SQUID. The first measurements using ion beams were carried out in the CNS experimental hall and RIKEN Ring Cyclotron (RRC). This paper first describes the principle of the conventional current monitor such as the Faraday cup and current transformers. Second, the progress of the LTS SQUID current monitor is discussed, and finally, the present status of the prototype of the LTS SQUID current monitor is discussed, and finally, the present status of the prototype of the HTS SQUID current monitor at RIKEN and the results of the first beam measurement are given. (author)

  5. Phase dependent impedance and temperature dependent response of microwave SQUID

    International Nuclear Information System (INIS)

    We report measurements of the microwave impedance of superconducting point contacts as a function of the quantum mechanical phase difference phi. They yield a conductance of the form G(phi) = G/sub o/(1+alpha cos phi) where alpha is a dimensionless parameter reflecting an interference between the Cooper pairs and the quasiparticles. Experimental results agree with a negative alpha approximately equal to -.5 which can be interpreted in terms of a phenomenological model that follows essentially the Time Dependent Landau Ginzburg theory (TDLG). In the second part we report measurements of the response of a microwave SQUID using a Ta point contact at various temperatures. They give a progression of operating conditions from the non-hysteretic to the hysteretic mode. The responses calculated by Soerensen and by Burhman and Jackel are in qualitative agreement with the measurements. We also present a theory based on a calculation of the reflection coefficient from the point contact. This theory reproduces the results of Bunhman and Jackel and Soerensen and is directly adaptable to our microwave geometry. In the last chapter we present a calculation that exhibits explicitly the dependence of the response on OMEGA = PHI/sub o/nu/I/sub X sub/R where nu is the microwave frequency, I/sub c/ and R the critical current and resistance of the junction and PHI/sub o/ fluxoid quantum, and that agrees with their data and their interpretation of it in terms of a limiting time tau for the supercurrent response with tau varies as DELTA(T)/sup -1/ where DELTA (T) is the BCS gap parameter

  6. High-Tc SQUID magnetometers for use in moderatemagnetically-shielded room

    OpenAIRE

    MATSUDA, Mizushi; Ono, S.; Kato, K.; Matsuura, T.; Oyama, H; Hayashi, A; Hirano, S.; Kuriki, S; YOKOSAWA, K.

    2001-01-01

    We have fabricated and characterized high-Tc planar SQUID magnetometers and first derivative gradiometers with directly-coupled pickup loops. The devices were made from single layer of YBa2Cu3O7-δ thin film on LSAT bicrystal substrate with 30° or 24° misorientation angle. Magnetic properties were investigated by applying a magnetic field B0 for the SQUID magnetometer patterned with holes to reduce the maximum structural width. We found an increasing low frequency noise with cooling fields B0 ...

  7. Investigation of helium-cooled planar transformer-coupled SQUID magnetometer

    International Nuclear Information System (INIS)

    We investigated helium-cooled planar transformer-coupled SQUID magnetometers with regard to their field resolution δB by varying the SQUID loop inductance Ls, input coils and the pick-up loop Lp. It was found that the pick-up-loop area Ap is the most important parameter for δB of transformer-coupled magnetometers. δB with Ap = 10 × 10 mm2 reached about 3 fTA/□Hz, even using direct readout scheme without any feedback circuitries.

  8. Thin film high-temperature superconducting flux transformers coupled to SQUIDs

    International Nuclear Information System (INIS)

    Using photolithographic patterning and laser deposition, we have constructed a sensitive thin-film SQUID magnetometer from YBa2Cu3O7-x (YBCO). The device consists of a flux transformer, deposited on one substrate, which is coupled to a thin-film YBCO SQUID, made with bi-epitaxial junctions, deposited on another substrate. At 77K, the magnetometer has attained a sensitivity of 1.8pTHz-1/2 at 1Hz, and has been used to measure the magnetic signal from the human heart. (orig.)

  9. Sensing of chemical substances using SQUID-based nuclear quadrupole resonance

    International Nuclear Information System (INIS)

    Using a high-Tc radio frequency superconducting quantum interference device (rf SQUID) with a normal metal transformer, we successfully detected the nuclear quadrupole resonance (NQR) at about 888 kHz of 14N in p-nitrotoluene (PNT) at room temperature. Only one coil was used as the resonator coil for the transmission and the pickup coil of the transformer. To reduce the influence of the strong excitation field, cross diodes and switches were inserted in the transformer. The signal-to-noise ratio of the NQR spectrum using high-Tc rf SQUID system was comparable to that of using a low noise preamplifier

  10. Role of squid in the Southern Ocean pelagic ecosystem and the possible consequences of climate change

    Science.gov (United States)

    Rodhouse, Paul G. K.

    2013-10-01

    Southern Ocean squid are important predators and prey and are a potential fishery resource. Their future under climate change is analysed from predictions of change by 2100 and assessments of the effects on squid biology. There are ˜18 Antarctic species of squid. Young feed primarily on crustaceans and switch later to fishes. They are preyed on by odontocetes, seals and seabirds - which together consume ˜34×106tyr-1 - and fish. As predators, squid are second to fish as biomass producers but recent evidence suggests predator consumption of squid needs to be reassessed. Fatty acid composition and stable nitrogen isotope ratios indicate some predators consume less squid in their diet than gut contents data suggest. Southern Ocean oceanography is unique in having circumpolar circulation and frontal systems and at high latitudes it is heavily influenced by sea ice. The Antarctic Peninsula is among the fastest warming regions worldwide but elsewhere the Southern Ocean is warming more slowly and the Ross Sea is probably cooling. Sea ice is receding in the Peninsula region and increasing elsewhere. Modelled predictions for 2100 suggest although the Southern Ocean will warm less than other oceans and sea ice will reduce. The Antarctic Circumpolar Current may shift slightly southwards with intensification of westerly winds but resolution of the models is insufficient to predict mesoscale change. Globally, pH of seawater has decreased by 0.1 units since the mid-1900s and is predicted to decrease by another 0.5 units by 2100. Impact on calcifying organisms will be high in the cold Southern Ocean where solubility of calcium carbonate is high. Predicted temperature increases are unlikely to have major effects on squid other than changes in distribution near the limits of their range; acidification may have greater impact. Small changes in large scale circulation are unlikely to affect squid but changes in mesoscale oceanography may have high impact. Change in sea ice extent

  11. Scanning high-T{sub c} SQUID imaging system for magnetocardiography

    Energy Technology Data Exchange (ETDEWEB)

    Yang, H-C [Department of Physics, National Taiwan University, Taipei 106, Taiwan (China); Wu, T-Y [Institute of Electro-Optical Science and Technology, National Normal Taiwan University 116, Taipei, Taiwan (China); Horng, H-E [Institute of Electro-Optical Science and Technology, National Normal Taiwan University 116, Taipei, Taiwan (China); Wu, C-C [Division of Cardiology, Department of Internal Medicine, National Taiwan University Hospital and National Taiwan University School of Medicine, Taipei 106, Taiwan (China); Yang, S Y [Institute of Electro-Optical Science and Technology, National Normal Taiwan University 116, Taipei, Taiwan (China); Liao, S-H [Department of Physics, National Normal Taiwan University, Taipei 116, Taiwan (China); Wu, C-H [Department of Physics, National Taiwan University, Taipei 106, Taiwan (China); Jeng, J T [Department of Mechanical Engineering, National Taipei University of Technology, Taipei, 105, Taiwan (China); Chen, J C [Department of Physics, National Taiwan University, Taipei 106, Taiwan (China); Chen, Kuen-Lin [Department of Physics, National Taiwan University, Taipei 106, Taiwan (China); Chen, M J [Department of Physics, National Taiwan University, Taipei 106, Taiwan (China)

    2006-05-15

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

  12. Research on high-T{sub c} rf SQUID and its applications

    Energy Technology Data Exchange (ETDEWEB)

    Wang, F; Ma, P; Xie, F X; Yang, T; Nie, R J; Liu, L Y; Wang, S Z; Dai, Y D [Department of Physics and State Key Laboratory for Mesoscopic Physics, Peking University, Beijing 100871 (China)

    2002-12-01

    We report on the research work at Peking University on optimizing high-temperature superconductor (HTS) rf superconducting quantum interference device (SQUID) systems and applying them in geophysical survey and magnetocardiography (MCG). Emphasis is placed on the design of comb-shape resonators for HTS rf SQUID systems and the experimental results of two applications: transient electromagnetics and MCG. The magnetic-field sensitivity of HTS magnetometers is now adequate for MCG applications. However, in order to be commercially used, the system still needs some improvements: development of suitable gradiometers and multi-channel systems.

  13. Isolation and Characterization of Collagen from Squid(Ommastreoges bartrami) Skin

    Institute of Scientific and Technical Information of China (English)

    YAN Mingyan; LI Bafang; ZHAO Xue

    2009-01-01

    Collagen of squid (Ommastrephes bartrami) skin was examined in the present study. Histology showed that collagen fiber in the skin was partially cross-linked with muscle fiber. Acid-solubilized collagen (ASC) and pepsin-solubilized collagen (PSC) were extracted from the skin and characterized. The results of amino acid composition and electrophoretic patterns revealed that ASC and PSC were both type Ⅰ collagen, containing α1 and α2 chains. FTIR (fourier transform infrared spectroscopy) investigations con-firmed the existence of helical arrangements in PSC of squid skin. The denaturation temperature (Td) and shrinkage temperature (Ts)of PSC were 29.4℃ and 52.8℃, respectively.

  14. Fabrication of Hg(Tl)-Ba-Ca-Cu-O high-Tc thin film RF-SQUID and its operation up to 121 K

    International Nuclear Information System (INIS)

    The development of high-Tc SQUID operating at temperatures higher than 77 K is very much desirable for reducing the cost of cryocoolers so that widespread field application of SQUID may become a reality. YBCO SQUID has been operated up to 87 K where as Bi (Pb) SrCaCuO and TlBaCaCuO high-Tc SQUID have shown SQUID modulation characteristics up to 101 K. The discovery of superconductivity in Hg-based high-Tc with maximum Tc ≅ 133 K at ambient pressure has generated hopes to develop high-Tc SQUID which can be operated at further higher temperatures. This paper reports fabrication of Hg(Tl)-Ba-Ca-Cu-O high-Tc thin film rf- SQUID using natural grain boundary junction and its operation; up to 121 K which is the highest temperature reported so far

  15. Effects of Gamma Irradiation on Shelf-Life and Sensory Scores of Squid Sundae under Accelerated Storage Conditions

    International Nuclear Information System (INIS)

    This study was conducted to examine the effects of gamma irradiation on the shelf-life and sensory scores of squid Sundae under accelerated storage conditions. Squid Sundae was stored at 37°C for 35 days following gamma irradiation at doses of 0, 10, and 20 kGy. For total viable cell counts, control and gamma-irradiated (GI) (10 kGy) squid Sundae were already spoiled in 4 days, whereas GI (20 kGy) squid Sundae showed complete suppression of bacterial growth during storage. There were no significant changes in pH values compared to the control. The VBN and TBARS (thiobarbituric acid reactive substance) values of GI (20 kGy) squid Sundae were significantly lower than those of the control. In addition, the induction period of GI (20 kGy) squid Sundae as measured by a Rancimat showed a higher level compared to that of the control. In the sensory evaluation, there were no significant changes between the control and GI samples. These results suggest that a dose of 20 kGy is the optimum and effective dose for preservation of squid Sundae. (author)

  16. Rotational population patterns and searches for the nuclear SQUID (Superconducting Quantum Interference Device)

    International Nuclear Information System (INIS)

    This paper presents new theoretical results for rotational population patterns in the nuclear SQUID effect. (The term nuclear SQUID is in analogy to the solid-state Superconducting Quantum Interference Devices.) The SQUID effect is an interesting new twist to an old quest to understand Coriolis anti-pairing (CAP) effects in nuclear rotational bands. Two-neutron transfer reaction cross sections among high-spin states have long been touted as more specific CAP probes than other nuclear properties. Heavy projectiles like Sn or Pb generally are recommended to pump the deformed nucleus to as high spin as possible for transfer. The interference and sign reversal of 2n transfer amplitudes at high spin, as predicted in the early SQUID work imposes the difficult requirement of Coulomb pumping to near back-bending spins at closest approach. For Pb on rare earths we find a dramatic departure from sudden-approximation, so that the population depression occurs as low as final spin 10h. 14 refs., 8 figs

  17. Measurement of SQUID noise levels for SuperCDMS SNOLAB detectors - Final Paper

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Maxwell [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-27

    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. The 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.

  18. SQUID sensor with additional compensation module for operation in an AC applied field

    International Nuclear Information System (INIS)

    A possible implementation of an in-vivo SQUID susceptometer able to estimate the liver iron concentration of humans uses a low frequency applied field together with a lock-in detection. The room-temperature magnetising coils and the detection coils are designed to minimize their mutual coupling. Nevertheless, deviation from ideal behaviour causes a residual signal in the detection coil, with an amplitude significantly larger than the patient's. In addition low frequency noise is added by any relative displacement of the magnetising and sensing coils. Thus, we designed a SQUID sensor using a compact compensating module to be used in a multichannel SQUID susceptometer. The sensor consists of two second order axial gradiometers, wounded one inside the other on the same support. The sensing channel is larger than the compensation channel which is only sensitive to the residual signal. Each gradiometer is coupled to a dc SQUID with parallel washer configuration. The output of the compensation channel is A/D converted and is processed by an adaptive algorithm running on a real time unit. The compensation signal is coupled to the sensing channel by an additional feedback loop. The performances of a prototype module will be presented

  19. Reversible stress softening of collagen based networks from the jumbo squid mantle (Dosidicus gigas)

    Energy Technology Data Exchange (ETDEWEB)

    Torres, F.G., E-mail: fgtorres@pucp.edu.pe [Department of Mechanical Engineering, Catholic University of Peru, Lima 32 (Peru); Troncoso, O.P.; Rivas, E.R. [Department of Mechanical Engineering, Catholic University of Peru, Lima 32 (Peru); Gomez, C.G. [Departament de Química Física and Institut de Ciencia dels Materials, Universitat de València, Dr. Moliner 50, Burjassot, E-46100 Valencia (Spain); Lopez, D. [Instituto de Ciencia y Tecnología de Polímeros, C.S.I.C., Calle Juan de la Cierva 3, 28006 Madrid (Spain)

    2014-04-01

    Dosidicus gigas is the largest and one of the most abundant jumbo squids in the eastern Pacific Ocean. In this paper we have studied the muscle of the mantle of D. gigas (DGM). Morphological, thermal and rheological properties were assessed by means of atomic force microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, differential scanning calorimetry, thermogravimetry and oscillatory rheometry. This study allowed us to assess the morphological and rheological properties of a collagen based network occurring in nature. The results showed that the DGM network displays a nonlinear effect called reversible stress softening (RSS) that has been previously described for other types of biological structures such as naturally occurring cellulose networks and actin networks. We propose that the RSS could play a key role on the way jumbo squids withstand hydrostatic pressure. The results presented here confirm that this phenomenon occurs in a wider number of materials than previously thought, all of them exhibiting different size scales as well as physical conformation. - Highlights: • We studied the structure property relationships of the jumbo squid mantle. • Rheological tests showed that such a mantle exhibits reversible stress softening (RSS). • RSS could also play a role on the way jumbo squids withstand hydrostatic pressure.

  20. Reversible stress softening of collagen based networks from the jumbo squid mantle (Dosidicus gigas)

    International Nuclear Information System (INIS)

    Dosidicus gigas is the largest and one of the most abundant jumbo squids in the eastern Pacific Ocean. In this paper we have studied the muscle of the mantle of D. gigas (DGM). Morphological, thermal and rheological properties were assessed by means of atomic force microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, differential scanning calorimetry, thermogravimetry and oscillatory rheometry. This study allowed us to assess the morphological and rheological properties of a collagen based network occurring in nature. The results showed that the DGM network displays a nonlinear effect called reversible stress softening (RSS) that has been previously described for other types of biological structures such as naturally occurring cellulose networks and actin networks. We propose that the RSS could play a key role on the way jumbo squids withstand hydrostatic pressure. The results presented here confirm that this phenomenon occurs in a wider number of materials than previously thought, all of them exhibiting different size scales as well as physical conformation. - Highlights: • We studied the structure property relationships of the jumbo squid mantle. • Rheological tests showed that such a mantle exhibits reversible stress softening (RSS). • RSS could also play a role on the way jumbo squids withstand hydrostatic pressure

  1. Loudness-dependent behavioral responses and habituation to sound by the longfin squid (Doryteuthis pealeii).

    Science.gov (United States)

    Mooney, T Aran; Samson, Julia E; Schlunk, Andrea D; Zacarias, Samantha

    2016-07-01

    Sound is an abundant cue in the marine environment, yet we know little regarding the frequency range and levels which induce behavioral responses in ecologically key marine invertebrates. Here we address the range of sounds that elicit unconditioned behavioral responses in squid Doryteuthis pealeii, the types of responses generated, and how responses change over multiple sound exposures. A variety of response types were evoked, from inking and jetting to body pattern changes and fin movements. Squid responded to sounds from 80 to 1000 Hz, with response rates diminishing at the higher and lower ends of this frequency range. Animals responded to the lowest sound levels in the 200-400 Hz range. Inking, an escape response, was confined to the lower frequencies and highest sound levels; jetting was more widespread. Response latencies were variable but typically occurred after 0.36 s (mean) for jetting and 0.14 s for body pattern changes; pattern changes occurred significantly faster. These results demonstrate that squid can exhibit a range of behavioral responses to sound include fleeing, deimatic and protean behaviors, all of which are associated with predator evasion. Response types were frequency and sound level dependent, reflecting a relative loudness concept to sound perception in squid. PMID:27236453

  2. Systematic value of the ultrastructure of the sucker surface in the squid family Mastigoteuthidae (Mollusca: Cephalopoda)

    NARCIS (Netherlands)

    Salcedo-Vargas, Mario Alejandro

    1995-01-01

    The ultrastructure of the sucker surface is described and its systematic value for mastigoteuthid squids, which bear minute suckers, is considered. An introduction to sucker terms is given and a redefinition of these terms is attempted. Using scanning electron microscopic data, two genera and four s

  3. Effect of electron beam on the microbiological and sensory characteristics of squid jeotkal and its ingredients

    International Nuclear Information System (INIS)

    A seasoned squid Jeotkal, Koran traditional fermented seafood, and its ingredients for manufacturing, including red hot pepper powder and ground garlic were irradiated by 0, 0.5, 1, 2 and 5 kGy electron beam and stored at 4 ℃ for 4 weeks to determine the changes of microorganisms and sensory characteristics. The initial contamination of squid Jeotkal such as total aerobic bacteria, yeast and mold, and coliform bacterial were at the levels of 2.88, 3.04 and 4.20 logCFU/g, respectively. However, 5 kGy electron beam irradiation reduced the total aerobic bacteria about 1 logCFU/g. Yeast and mold and coliform bacterial were reduced 1 ∼ 2 logCFU/g after 2 kGy irradiation and reached to undetected level when the sample was irradiated at 5 kGy and following storage at 4 ℃ for 4 weeks. Sensory characteristics showed that 5 kGy electron beam irradiation did not adversely affect overall acceptability of squid Jeotkal and its ingredients during 4 ℃ storage. Therefore, electron beam irradiation is one of the possible methods to improve storage stability of seasoned squid Jeotkal. (authors)

  4. 77 FR 38566 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Science.gov (United States)

    2012-06-28

    ... Omnibus Amendment to implement annual catch limits and accountability measures (76 FR 60606). Among other... the 2012 fishing year (2012 butterfish specifications; 77 FR 16472; March 21, 2012), the Council found... United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Framework Adjustment 6...

  5. 76 FR 13887 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish (MSB...

    Science.gov (United States)

    2011-03-15

    ... Plan (FMP) (76 FR 8306; February 14, 2011). Butterfish catches have been constrained to low levels... days. ] NMFS policy guidelines for the use of emergency rules (62 FR 44421; August 21, 1997) specify... United States; Atlantic Mackerel, Squid, and Butterfish (MSB) Fishery; Revision of 2011...

  6. 75 FR 5537 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Science.gov (United States)

    2010-02-03

    ... was published on November 12, 2009 (74 FR 58234), and the public comment period for the proposed rule... revised through Amendment 9 to the FMP (Amendment 9) (73 FR 37382, July 1, 2008) to reflect the analytical... United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Specifications and Management...

  7. Hydrolysates from scallop and squid processing byproducts as specialty aquafeed ingredients

    Science.gov (United States)

    Around 9,000 MT of squid (Loligo pealei) is landed annually in Rhode Island, USA, most of which is processed resulting in 40-50% unutilized byproducts (about 3,500 MT). On the other hand, the sea scallop (Placopecten magellanicus) resource off New England is currently at historic high levels of 22,7...

  8. Measurement of fMCG Signals using an Axial Type First-Order SQUID Gradiometer System

    International Nuclear Information System (INIS)

    We have fabricated a low-noise 61-channel axial-type first-order gradiometer system for measuring fetal magnetocardiography(MCG) signals. Superconducting quantum interference device(SQUID) sensor was based on double relaxation oscillation SQUID(DROS) for detecting biomagnetic signal, such as MCG, magnetoencphalogram(MEG) and fetal-MCG. The SQUID sensor detected axial component of fetal MCG signal. The pickup coil of SQUID sensor was wound with 120 μm NbTi wire on bobbin(20 mm diameter) and was a first-order gradiometer to reject the environment noise. The sensors have low white noise of 3 fT/Hz1/2 at 100 Hz on average. The fetal MCG was measured from 24 - 36 weeks fetus in a magnetically shielded room(MSR) with shielding factor of 35 dB at 0.1 Hz and 80 dB at 100 Hz(comparatively mild shielding). The MCG signal contained maternal and fetal MCG. Fetal MCG could be distinguished relatively easily from maternal MCG by using independent component analysis(ICA) filter. In addition, we could observe T peak as well as QRS wave, respectively. It will be useful in detecting fetal cardiac diseases.

  9. Magnetic properties of thin Ni films measured by a dc SQUID-based magnetic microscope

    DEFF Research Database (Denmark)

    Snigirev, O.V.; Andreev, K.E.; Tishin, A.M.; Gudoshnikov, S.A.; Bohr, Jakob

    1997-01-01

    We have applied a scanning HTS (high-temperature superconductor) de SQUID (superconducting quantum interference device) -based magnetic microscope to study the magnetic properties of Au/Ni/Si(100) films in the thickness range from 8 to 200 Angstrom at T = 77 K. A one-domain structure with in...

  10. A broadband dc SQUID based rf amplifier: experimental basics and development concept

    DEFF Research Database (Denmark)

    Prokopenko, G.V.; Shitov, S.V.; Mygind, Jesper

    2002-01-01

    We present a concept of a broadband IF amplifier based on experimental results obtained with a dc SQUID rf amplifier (SQA). The frequency range is broadened by using several SQAs, each one tuned to its own central frequency at both input and output; the numerical simulations are presented. A...

  11. 77 FR 7544 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Science.gov (United States)

    2012-02-13

    ... November 7, 2011 (76 FR ] 68642). The final measures in that action included: A tiered limited access... purposes of Executive Order 12866. Correction In the Federal Register of November 7, 2011, in FR Doc. 2011... United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Amendment 11; Correction...

  12. 75 FR 43090 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Science.gov (United States)

    2010-07-23

    ...-2179, fax (978) 281-9135. SUPPLEMENTARY INFORMATION: On June 30, 2010 (75 FR 37739), a temporary rule... equivalent is 10,770 mt. Correction In rule FR Doc. 2010-15933 published on June 30, 2010, (75 FR 37739) make... United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Adjustment to the Loligo Trimester...

  13. 77 FR 71720 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Science.gov (United States)

    2012-12-04

    ... on September 21, 2012 (77 FR 58507). Additional background information and detail on why and how... 11 to the MSB FMP (76 FR 68642, November 7, 2011) implemented a three-tiered mackerel limited access... United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Framework Adjustment 5...

  14. Measurement of fMCG Signals using an Axial Type First-Order SQUID Gradiometer System

    Energy Technology Data Exchange (ETDEWEB)

    Yu, K. K.; Kim, K.; Kang, C. S.; Kim, J. M.; Lee, Y. H. [Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of)

    2009-04-15

    We have fabricated a low-noise 61-channel axial-type first-order gradiometer system for measuring fetal magnetocardiography(MCG) signals. Superconducting quantum interference device(SQUID) sensor was based on double relaxation oscillation SQUID(DROS) for detecting biomagnetic signal, such as MCG, magnetoencphalogram(MEG) and fetal-MCG. The SQUID sensor detected axial component of fetal MCG signal. The pickup coil of SQUID sensor was wound with 120 {mu}m NbTi wire on bobbin(20 mm diameter) and was a first-order gradiometer to reject the environment noise. The sensors have low white noise of 3 fT/Hz{sup 1/2} at 100 Hz on average. The fetal MCG was measured from 24 - 36 weeks fetus in a magnetically shielded room(MSR) with shielding factor of 35 dB at 0.1 Hz and 80 dB at 100 Hz(comparatively mild shielding). The MCG signal contained maternal and fetal MCG. Fetal MCG could be distinguished relatively easily from maternal MCG by using independent component analysis(ICA) filter. In addition, we could observe T peak as well as QRS wave, respectively. It will be useful in detecting fetal cardiac diseases.

  15. SQUID sensor with additional compensation module for operation in an AC applied field

    Science.gov (United States)

    Della Penna, S.; Cianflone, F.; Del Gratta, C.; Erné, S. N.; Granata, C.; Pasquarelli, A.; Pentiricci, A.; Pizzella, V.; Russo, M.; Romani, G. L.

    2006-06-01

    A possible implementation of an in-vivo SQUID susceptometer able to estimate the liver iron concentration of humans uses a low frequency applied field together with a lock-in detection. The room-temperature magnetising coils and the detection coils are designed to minimize their mutual coupling. Nevertheless, deviation from ideal behaviour causes a residual signal in the detection coil, with an amplitude significantly larger than the patient's. In addition low frequency noise is added by any relative displacement of the magnetising and sensing coils. Thus, we designed a SQUID sensor using a compact compensating module to be used in a multichannel SQUID susceptometer. The sensor consists of two second order axial gradiometers, wounded one inside the other on the same support. The sensing channel is larger than the compensation channel which is only sensitive to the residual signal. Each gradiometer is coupled to a dc SQUID with parallel washer configuration. The output of the compensation channel is A/D converted and is processed by an adaptive algorithm running on a real time unit. The compensation signal is coupled to the sensing channel by an additional feedback loop. The performances of a prototype module will be presented.

  16. XRD studies of beta-chitin from squid pen with calcium solvent.

    Science.gov (United States)

    Nagahama, H; Higuchi, T; Jayakumar, R; Furuike, T; Tamura, H

    2008-05-01

    The crystalline structure of beta-chitin from squid pen was investigated by X-ray diffraction (XRD). The purified beta-chitin was prepared from bigfin reefsquid pen. beta-Chitin was treated with saturated calcium chloride dihydrate/alchohol (CaCl(2).2H(2)O/MeOH) solvent system at different conditions for XRD studies. The change of crystallinity of beta-chitin from squid pen was studied by using the fiber photographs on imaging plates. The results showed that the diffraction peak (010) was shifted. It means that the lattice plane (010) interplanarilly spreaded to 3.4A, when the squid pen was washed with water after treatment of Ca solvent. Furthermore, when the squid pen was dried after treatment of Ca solvent and washing with water, interplanar spacing of (010) inversely shrank to 1.1A. These results suggested that Ca solvent especially influences the plane (010) of beta-chitin structure. PMID:18036656

  17. Compensation electronics for larger dynamic range of a SQUID based nondestructive evaluation system

    Science.gov (United States)

    Kreutzbruck, M. v.; Theiss, A.; Mück, M.; Heiden, C.

    1999-09-01

    We have developed a compensation system for any given SQUID sensor which allows sensitive eddy current measurements above 100 Hz in the presence of strong and slowly varying background fields. High Tc SQUIDs have been used successfully in nondestructive evaluation (NDE) systems based on eddy current excitation when searching for defects in conductive samples such as aircraft parts. Due to their high and frequency independent field resolution and their excellent spatial resolution, SQUIDs provide in the case of deep lying defects—compared to other conventional electromagnetic NDE systems—a more reliable crack detection. Fast readout electronics having an unsurpassed dynamic range of up to eight orders of magnitude enabled us to perform measurements in an environment polluted with electromagnetic noise, e.g., an aircraft hangar. Nevertheless, test objects containing ferromagnetic structures with a high remanent magnetization, such as aircraft wheels or steel bolts in an aircraft wing, very often cause instabilities of the flux-locked loop operation of the SQUID. To prevent unlocking, we have developed a new background field compensation scheme. Special compensation electronics take care of slowly varying magnetic fields of up to 1 mT/s and allow us to perform eddy current measurements in the presence of slow (<30 Hz) background field variations of up to 5 mT.

  18. Relation between quantum NOT gate speed and asymmetry of the potential of RF-SQUID

    International Nuclear Information System (INIS)

    This paper investigates the relationship between the speed of a quantum not gate and the asymmetry of the potential in an interactive system formed by a two-level RF-SQUID qubit and a classical microwave pulse. The RF-SQUID is characterized by an asymmetric double well potential which gives rise to diagonal matrix elements that describe the interaction of the SQUID with the microwave pulse. And the diagonal matrix elements account for the interaction of the microwave pulse with the SQUID. The results indicate that, when the angular frequency of the microwave field is chosen as near resonate with the transition |0> ↔ |1>0, i.e. ω1 - ω0 ≈ ωm, (1) the gate speed is decided by three factors, the Rabi frequency, the difference of the diagonal matrix elements between the two levels, and the angular frequency of the applied microwave pulse ωm; (2) the gate speed descends when the asymmetry of the potential is considered

  19. Impact of high hydrostatic pressure on non-volatile and volatile compounds of squid muscles.

    Science.gov (United States)

    Yue, Jin; Zhang, Yifeng; Jin, Yafang; Deng, Yun; Zhao, Yanyun

    2016-03-01

    The effects of high hydrostatic pressure processing (HHP at 200, 400 or 600MPa) on non-volatile and volatile compounds of squid muscles during 10-day storage at 4°C were investigated. HHP increased the concentrations of Cl(-) and volatile compounds, reduced the level of PO4(3-), but did not affect the contents of 5'-uridine monophosphate (UMP), 5'-guanosine monophosphate (GMP), 5'-inosine monophosphate (IMP), Na(+) and Ca(2+) in squids on Day 0. At 600MPa, squids had the highest levels of 5'-adenosine monophosphate, Cl(-) and lactic acid, but the lowest contents of CMP and volatile compounds on Day 10. Essential free amino acids and succinic acids were lower on Day 0 than on Day 10. HHP at 200MPa caused higher equivalent umami concentration (EUC) on Day 0, and the EUC decreased with increasing pressure on Day 10. Generally, HHP at 200MPa was beneficial for improving EUC and volatile compounds of squids. PMID:26471521

  20. Sphingoid esters from the molecular distillation of squid oil: A preliminary bioactivity determination.

    Science.gov (United States)

    Saliu, Francesco; Longhin, Eleonora; Salanti, Anika; Degano, Ilaria; Della Pergola, Roberto

    2016-06-15

    A mixture of sphingoid esters was isolated (1.4% w/w) from the molecular distillation of crude squid visceral oil. A preliminary investigation on the bioactivity profile and toxic potential of this residue was carried out by in vitro experiments. No cytotoxicity and a moderate lipase inhibition activity were highlighted. PMID:26868543

  1. Squid 'ear bones' (statoliths) from the Jurassic succession of South-west England

    Science.gov (United States)

    Hart, Malcolm; Page, Kevin; Price, Gregory; Smart, Christopher

    2015-04-01

    Squid 'ear bones' - or statoliths - are a part of the balancing organs of modern and probably most fossil squids. Over the course of the last 10 years fossil statoliths have been discovered in the Jurassic sediments of the Wessex Basin (South-west England). They are probably all related to teuthids, such as Belemnotheutis antiquus Pearce, of Callovian-Oxfordian age. Thus far, we have identified four possible 'species' of statolith that are in the process of being formally described, named and their potential relationships determined. The sediments from which these statoliths have been recorded also contain squid hooklets (onycites), otoliths (fish 'ear bones') and other microfossils (including foraminifera). All are, therefore, of marine origin. In the case of the Christian Malford and Ashton Keynes lagerstätte (of late Callovian age), the statoliths are associated with exceptional, soft-bodied preservation of squid and it may be possible to determine the parent animal of the recorded statoliths. A number of museum collections (Natural History Museum [London], Natural History Museum [Paris], Senckenberg [Frankfurt], Smithsonian Institution [Washington], etc.) are being investigated in order to trace the possible host animals for all of the recorded statoliths. Despite many thousands of samples of Cretaceous sediments being investigated for foraminifera over the past 40+ years, no statoliths have been recorded and none are known from the literature.

  2. A broadband dc SQUID based rf amplifier: experimental basics and development concept

    DEFF Research Database (Denmark)

    Prokopenko, G.V.; Shitov, S.V.; Mygind, Jesper

    2002-01-01

    We present a concept of a broadband IF amplifier based on experimental results obtained with a dc SQUID rf amplifier (SQA). The frequency range is broadened by using several SQAs, each one tuned to its own central frequency at both input and output; the numerical simulations are presented. A.......(C) 2002 Elsevier Science B.V. All rights reserved....

  3. Metallic contaminant detection system using multi-channel high Tc SQUIDs

    Science.gov (United States)

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

    2012-10-01

    We have developed the magnetic metallic contaminant detectors using multiple high Tc SQUID gradiometers for industrial products. Finding ultra-small metallic contaminants is a big issue for manufacturers producing commercial products. The quality of industrial products such as lithium ion batteries can deteriorate by the inclusion of tiny metallic contaminants. When the contamination does occur, the manufacturer of the product suffers a great loss to recall the tainted products. Metallic particles with outer dimension less than 50 μm cannot be detected by a conventional X-ray imaging. Therefore a high sensitive detection system for small foreign matters is required. However, in most of the cases, the matrix of an active material coated sheet electrode is magnetized and the magnetic signal from the matrix is large enough to mask the signal from contaminants. Thus we have developed a detection system based on a SQUID gradiometer and a horizontal magnetization to date. For practical use, we should increase the detection width of the system by employing multiple sensors. We successfully realized an eight-channel high-Tc SQUID gradiometer system for inspection of sheet electrodes of a lithium ion battery with width of at least 60 to 70 mm. Eight planar SQUID gradiometers were mounted with a separation of 9.0 mm. As a result, small iron particles of less than 50 μm were successfully measured. This result suggests that the system is a promising tool for the detection of contaminants in a lithium ion battery.

  4. Compact noise thermometer for mK-temperatures based on integrated SQUID magnetometers

    International Nuclear Information System (INIS)

    We report on the development and optimization of very compact noise thermometers for the temperature range of the PLTS-2000. They are based on the detection of the magnetic field fluctuations above the surface of a metal body by means of thin film SQUID magnetometers. The thermally driven Johnson noise currents inside a metal body produce fluctuating magnetic fields, which can be detected by highly sensitive low-Tc dc-SQUID magnetometers or gradiometers placed close to the metal surface. The fundamental fluctuation-dissipation theorem provides a direct relation between temperature and noise currents or field fluctuations to be measured: The power spectral density of the thermal magnetic flux density noise is strictly proportional to the temperature, provided the electrical conductivity does not change. Thus, the temperature of the metal body can be determined from the spectrum of the magnetic flux detected by the SQUID, making up a semi-primary thermometer. Since the spectrum of these fluctuations depends significantly on the configuration of pick-up coil and metal body, it must be optimized to achieve the largest noise signal (power) for a limited chip area. This has been done resulting in thin film miniature multi-loop SQUID gradiometers. We present measurements of the integrated magnetic field fluctuation thermometer characterizing its sensitivity and speed. (orig.)

  5. Comparison live adult Artemia and squid meat on the growth of Penaeid shrimp Metapenaeus dobsoni (Miers)

    Digital Repository Service at National Institute of Oceanography (India)

    Nair, S.R.S.; Achuthankutty, C.T.; Royan, J.P.

    An experiment lasting 14 weeks was conducted to compare the efficiency of live adult Artemia with fresh squid meat on growth of penaeid shrimp Metapenaeus dobsoni. The shrimps were found actively feeding on live Artemia and grew 84% more than those...

  6. Metallic contaminant detection system using multi-channel high Tc SQUIDs

    International Nuclear Information System (INIS)

    We have developed the magnetic metallic contaminant detectors using multiple high Tc SQUID gradiometers for industrial products. Finding ultra-small metallic contaminants is a big issue for manufacturers producing commercial products. The quality of industrial products such as lithium ion batteries can deteriorate by the inclusion of tiny metallic contaminants. When the contamination does occur, the manufacturer of the product suffers a great loss to recall the tainted products. Metallic particles with outer dimension less than 50 μm cannot be detected by a conventional X-ray imaging. Therefore a high sensitive detection system for small foreign matters is required. However, in most of the cases, the matrix of an active material coated sheet electrode is magnetized and the magnetic signal from the matrix is large enough to mask the signal from contaminants. Thus we have developed a detection system based on a SQUID gradiometer and a horizontal magnetization to date. For practical use, we should increase the detection width of the system by employing multiple sensors. We successfully realized an eight-channel high-Tc SQUID gradiometer system for inspection of sheet electrodes of a lithium ion battery with width of at least 60 to 70 mm. Eight planar SQUID gradiometers were mounted with a separation of 9.0 mm. As a result, small iron particles of less than 50 μm were successfully measured. This result suggests that the system is a promising tool for the detection of contaminants in a lithium ion battery.

  7. High-Tc SQUID Application for Roll to Roll Metallic Contaminant Detector

    International Nuclear Information System (INIS)

    A sensitive eight-channel high-Tc Superconducting Interference Device (SQUID) detection system for magnetic contaminant in a lithium ion battery anode was developed. Finding ultra-small metallic foreign matter is an important issue for a manufacturer because metallic contaminants carry the risk of an internal short. When contamination occurs, the manufacturer of the product suffers a great loss from recalling the tainted product. Metallic particles with outer dimensions smaller than 100 microns cannot be detected using a conventional X-ray imaging system. Therefore, a highly sensitive detection system for small foreign matter is required. We have already developed a detection system based on a single-channel SQUID gradiometer and horizontal magnetization. For practical use, the detection width of the system should be increased to at least 65 mm by employing multiple sensors. In this paper, we present an 8-ch high-Tc SQUID roll-to-roll system for inspecting a lithium-ion battery anode with a width of 65 mm. A special microscopic type of a cryostat was developed upon which eight SQUID gradiometers were mounted. As a result, small iron particles of 35 microns on a real lithium-ion battery anode with a width of 70 mm were successfully detected. This system is practical for the detection of contaminants in a lithium ion battery anode sheet.

  8. SQUIDs as Detectors in a New Experiment to Measure the Neutron Electric Dipole Moment

    Energy Technology Data Exchange (ETDEWEB)

    Espy, M.A.; Cooper, M.; Lamoreaux, S.; Kraus, R.H., Jr.; Matlachov, A.; Ruminer, P.

    1998-09-13

    A new experiment has been proposed at Los Alamos National Laboratory to measure the neutron electric dipole moment (EDM) to 4x10{sup {minus}28} ecm, a factor of 250 times better than the current experimental limit. Such a measure of the neutron EDM would challenge the theories of supersymmetry and time reversal violation as the origin of the observed cosmological asymmetry in the ratio of baryons to antibaryons. One possible design for this new experiment includes the use of LTC SQUIDs coupled to large ({approximately}100 cm{sup 2}) pick-up coils to measure the precession frequency of the spin-polarized {sup 3}He atoms that act as polarizer, spin analyzer, detector, and magnetometer for the ultra-cold neutrons used in the experiment. The method of directly measuring the {sup 3}He precession signal eliminates the need for very uniform magnetic fields (a major source of systematic error in these types of experiments). It is estimated that a flux of {approximately}2x10{sup {minus}16} Tm{sup 2} (0.1 F{sub 0}) will be coupled into the pick-up coils. To achieve the required signal-to-noise ratio one must have a flux resolution of d F{sub SQ}=2x10{sup {minus}6} F{sub 0}/{radical}Hz at 10 Hz. While this is close to the sensitivity available in commercial devices, the effects of coupling to such a large pick-up coil and flux noise from other sources in the experiment still need to be understood. To determine the feasibility of using SQUIDs in such an application we designed and built a superconducting test cell, which simulates major features of the proposed EDM experiment, and we developed a two-SQUID readout system that will reduce SQUID noise in the experiment. We present an overview of the EDM experiment with SQUIDs, estimations of required SQUID parameters and experimental considerations. We also present the measured performance of a single magnetometer in the test cell as well as the performance of the two SQUID readout technique

  9. Low-Frequency Noise in High-T Superconductor Josephson Junctions, Squids, and Magnetometers.

    Science.gov (United States)

    Miklich, Andrew Hostetler

    The design and performance of high-T_ {rm c} dc superconducting quantum interference devices (SQUIDs), the junctions that comprise them, and magnetometers made from them are described, with special attention paid to sources of 1/f noise. Biepitaxial junctions are found to have large levels of critical current fluctuations which make them unsuitable for low-noise SQUIDs. This noise suggests a poorly connected interface at the grain boundary junction. SQUIDs from bicrystal junctions, in contrast, have levels of critical current noise that are controllable using bias current reversal techniques which leave the noise white down to frequencies of a few Hz. A SQUID with an energy resolution of 1.5times 10^{-30} J Hz^ {-1} at 1 Hz is reported. Magnetometers in which a (9 mm)^2 pickup loop is directly coupled to a SQUID body have achieved field resolutions of 93 fT Hz^{-1/2} down to frequencies below 1 Hz, improving to 39 fT Hz^{-1/2} at 1 Hz with the addition of a 50 mm-diameter single-turn flux transformer. Although the performance of these devices is sufficient for single -channel biomagnetometry or geophysical studies, their relatively poor coupling to the pickup loop makes it difficult to satisfy the competing goals of high field resolution and small detector size necessary for multichannel biomagnetic imaging. Improved coupling is demonstrated by the use of multiturn-input-coil flux transformers, and a resolution of 35 fT Hz^{-1/2} in the white noise region is reported with a (10 mm) ^2 pickup loop. However, additional 1/f noise from the processed multilayer structures in the transformer limits the resolution at 1 Hz to 114 fT Hz^ {-1/2}. High-T_{ rm c} SQUIDs are shown to exhibit additional 1/f noise when they are cooled in a nonzero static magnetic field because of the additional flux vortices trapped in the film, with the noise power at 1 Hz typically increasing by a factor of 10-20 in a field of 0.05 mT (0.5 G). Finally, a SQUID-based voltmeter with a resolution

  10. Low-frequency noise in high-(Tc) superconductor Josephson junctions, SQUIDs, and magnetometers

    Science.gov (United States)

    Miklich, A. H.

    1994-05-01

    Design and performance of high-T(sub c) dc superconducting quantum interference devices (SQUID's), junctions that comprise them, and magnetometers made from them are described, with attention to sources of 1/f noise. Biepitaxial junctions are found to have large levels of critical current fluctuations which make them unsuitable for low-noise SQUID's; this suggests a poorly connected interface at the grain boundary junction. SQUID's from bicrystal junctions have levels of critical current noise controllable using bias current reversal techniques which leave the noise white down to frequencies of a few Hz. A SQUID with an energy resolution of 1.5 x 10(exp -30) J Hz(exp -1) at 1 Hz is reported. Magnetometers in which a (9 mm)(exp 2) pickup loop is directly coupled to a SQUID body have achieved field resolutions of 93 fT Hz(exp -1/2) down to frequencies below 1 Hz, improving to 39 fT Hz(exp -1/2) at 1 Hz with the addition of a 50mm-diameter single-turn flux transformer. Poor coupling to pickup loop makes it difficult to satisfy competing goals of high field resolution and small detector size necessary for multichannel biomagnetic imaging. Improved coupling is demonstrated by the use of multiturn-input-coil flux transformers, and a resolution of 35 fT Hz(exp -1/2) in the white noise region is reported with a (10 mm)(exp 2) pickup loop. However, additional 1/f noise from processed multilayer structures in the transformer limits the resolution at 1 Hz to 114 fT Hz(exp -1/2). High-T(sub c) SQUID's exhibit additional 1/f noise when cooled in a nonzero static magnetic field because of additional flux vortices trapped in the film, with the noise power at 1 Hz typically increasing by a factor of 10-20 in a field of 0.05mT (0.5 G). Finally, a SQUID-based voltmeter with a resolution of 9.2 pV Hz(exp -1/2) at 10 Hz (24 pV Hz(exp -1/2) at 1 Hz) is described.

  11. Fishery biology of jumbo flying squid Dosidicus gigas off Costa Rica Dome

    Science.gov (United States)

    Chen, Xinjun; Li, Jianghua; Liu, Bilin; Li, Gang; Lu, Huajie

    2014-06-01

    The jumbo flying squid ( Dosidicus gigas) population was surveyed with the help of Chinese squid jigging vessels off the Costa Rica Dome (4°-11°N, 90°-100°W) in 2009 and 2010. The daily catch of D. gigas in the two survey cruises ranged from 0 to 5.5 t and was mostly obtained from the areas bounded by 6°-9°N and 91°-94°W and by 6°30'-7°30'N and 96°-97°W. The sea surface temperature in the areas yielding the most catch ranged from 27.5 to 29°C. The sex ratio of the total catch was 3.75:1 (female: male). The mantle length of the squid ranged from 211 to 355 mm (male) and from 204 to 429 mm (female) with an average of 297.9 and 306.7 mm, respectively. In the relationship of the mantle length (mm) and body weight (g) of the squid, there was no significant difference between sexes. The female and male were at a similar maturity, and most individuals are maturing or have matured with a few females being spent. The size (mantle length) and age at the first sexual maturity were 297 mm and 195 d in females, and less than 211 mm and 130 d in males, respectively. Most of the sampled stomachs (70.6%) had no food remains. The major preys of the squids were fish, cephalopods and crustaceans, with the most abundant Myctophum orientale and D. gigas. The preys in more than 65% of the non-empty sampled stomachs evidenced the cannibalism of D. gigas. The results improved current understanding of the fishery biology of D. gigas off the Costa Rica Dome, which may facilitate the assessment and management of relative fishery resources.

  12. Sequential isotopic signature along gladius highlights contrasted individual foraging strategies of jumbo squid (Dosidicus gigas.

    Directory of Open Access Journals (Sweden)

    Anne Lorrain

    Full Text Available BACKGROUND: Cephalopods play a major role in marine ecosystems, but knowledge of their feeding ecology is limited. In particular, intra- and inter-individual variations in their use of resources has not been adequatly explored, although there is growing evidence that individual organisms can vary considerably in the way they use their habitats and resources. METHODOLOGY/PRINCIPAL FINDINGS: Using δ(13C and δ(15N values of serially sampled gladius (an archival tissue, we examined high resolution variations in the trophic niche of five large (>60 cm mantle length jumbo squids (Dosidicus gigas that were collected off the coast of Peru. We report the first evidence of large inter-individual differences in jumbo squid foraging strategies with no systematic increase of trophic level with size. Overall, gladius δ(13C values indicated one or several migrations through the squid's lifetime (∼8-9 months, during which δ(15N values also fluctuated (range: 1 to 5‰. One individual showed an unexpected terminal 4.6‰ δ(15N decrease (more than one trophic level, thus indicating a shift from higher- to lower-trophic level prey at that time. The data illustrate the high diversity of prey types and foraging histories of this species at the individual level. CONCLUSIONS/SIGNIFICANCE: The isotopic signature of gladii proved to be a powerful tool to depict high resolution and ontogenic variations in individual foraging strategies of squids, thus complementing traditional information offered by stomach content analysis and stable isotopes on metabolically active tissues. The observed differences in life history strategies highlight the high degree of plasticity of the jumbo squid and its high potential to adapt to environmental changes.

  13. Magnetic relaxometry with an atomic magnetometer and SQUID sensors on targeted cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Cort [Sandia National Laboratories, P.O. Box 5800, Albuquerque, NM 87185 (United States); Adolphi, Natalie L. [Department of Biochemistry and Molecular Biology, University of New Mexico, Albuquerque, NM 87131 (United States); Butler, Kimberly L.; Lovato, Debbie M.; Larson, Richard [Department of Pathology, University of New Mexico, Cancer Research and Treatment Center, Albuquerque, NM 87131 (United States); Schwindt, Peter D.D. [Sandia National Laboratories, P.O. Box 5800, Albuquerque, NM 87185 (United States); Flynn, Edward R., E-mail: seniorsci@comcast.net [Senior Scientific, LLC, 11109 Country Club NE, Albuquerque, NM 87111 (United States)

    2012-08-15

    Magnetic relaxometry methods have been shown to be very sensitive in detecting cancer cells and other targeted diseases. Superconducting quantum interference device (SQUID) sensors are one of the primary sensor systems used in this methodology because of their high sensitivity with demonstrated capabilities of detecting fewer than 100,000 magnetically-labeled cancer cells. The emerging technology of atomic magnetometers (AMs) represents a new detection method for magnetic relaxometry with high sensitivity and without the requirement for cryogens. We report here on a study of magnetic relaxometry using both AM and SQUID sensors to detect cancer cells that are coated with superparamagnetic nanoparticles through antibody targeting. The AM studies conform closely to SQUID sensor results in the measurement of the magnetic decay characteristics following a magnetization pulse. The AM and SQUID sensor data are well described theoretically for superparamagnetic particles bound to cells and the results can be used to determine the number of cells in a cell culture or tumor. The observed fields and magnetic moments of cancer cells are linear with the number of cells over a very large range. The AM sensor demonstrates very high sensitivity for detecting magnetically labeled cells, does not require cryogenic cooling and is relatively inexpensive. - Highlights: Black-Right-Pointing-Pointer Magnetic relaxometry is used to study antibody targeted nanoparticles and cells. Black-Right-Pointing-Pointer Atomic magnetometer and SQUID sensor performances are compared. Black-Right-Pointing-Pointer High sensitivity of magnetic relaxometry for cancer cell detection is demonstrated. Black-Right-Pointing-Pointer Magnetic relaxometry decay curves from cancer cells are fit by a log function.

  14. Magnetic relaxometry with an atomic magnetometer and SQUID sensors on targeted cancer cells

    International Nuclear Information System (INIS)

    Magnetic relaxometry methods have been shown to be very sensitive in detecting cancer cells and other targeted diseases. Superconducting quantum interference device (SQUID) sensors are one of the primary sensor systems used in this methodology because of their high sensitivity with demonstrated capabilities of detecting fewer than 100,000 magnetically-labeled cancer cells. The emerging technology of atomic magnetometers (AMs) represents a new detection method for magnetic relaxometry with high sensitivity and without the requirement for cryogens. We report here on a study of magnetic relaxometry using both AM and SQUID sensors to detect cancer cells that are coated with superparamagnetic nanoparticles through antibody targeting. The AM studies conform closely to SQUID sensor results in the measurement of the magnetic decay characteristics following a magnetization pulse. The AM and SQUID sensor data are well described theoretically for superparamagnetic particles bound to cells and the results can be used to determine the number of cells in a cell culture or tumor. The observed fields and magnetic moments of cancer cells are linear with the number of cells over a very large range. The AM sensor demonstrates very high sensitivity for detecting magnetically labeled cells, does not require cryogenic cooling and is relatively inexpensive. - Highlights: ► Magnetic relaxometry is used to study antibody targeted nanoparticles and cells. ► Atomic magnetometer and SQUID sensor performances are compared. ► High sensitivity of magnetic relaxometry for cancer cell detection is demonstrated. ► Magnetic relaxometry decay curves from cancer cells are fit by a log function.

  15. The biology and ecology of the jumbo squid Dosidicus gigas (Cephalopoda in Chilean waters: a review

    Directory of Open Access Journals (Sweden)

    Christian M Ibáñez

    2015-07-01

    Full Text Available ABSTRACT. The jumbo squid Dosidicus gigas is the most abundant cephalopod species in the southeastern Pacific Ocean, which supports the biggest cephalopod fishery in the world. Due to its growing economic importance, the population growth and distributional expansion of this squid is being increasingly studied. Nevertheless, some basic features of the biology of D. gigas are still unknown or have been poorly investigated. In this review we summarize the known information regarding the biology and ecology of this species in the southeastern Pacific Ocean; we focus on the Chilean region in order to propose hypotheses and research lines for a better understanding the life history of this organism. Available data on the size structure, reproduction and genetics of D. gigas allows us to propose hypotheses related to the squid's life history traits. Based on the current literature and publications of colleagues, we propose two hypotheses regarding the effect of spatial variation on the life history of D. gigas. Hypothesis 1: Squids mature at large sizes and spawn in oceanic waters with warm temperatures where paralarvae and juveniles develop. Immature squids migrate near shore to feed, grow and mature, and then return to the offshore sites to spawn. Hypothesis 2: Alternatively, juvenile D. gigas in the oceanic zone do not migrate to coastal waters and mature at small sizes compared to individuals living near the coast that mature at larger size and migrate to oceanic waters to spawn. We provide background information about the feeding behavior and parasitism of this species, suggesting that D. gigas is an important trophic link in the southeastern Pacific marine ecosystem. However, more studies on the feeding habits, reproduction and parasite load are needed not only to test hypotheses proposed in this study, but also to advance the overall knowledge of this species.

  16. Fishery Biology of Jumbo Flying Squid Dosidicus gigas off Costa Rica Dome

    Institute of Scientific and Technical Information of China (English)

    CHEN Xinjun; LI Jianghua; LIU Bilin; LI Gang; LU Huajie

    2014-01-01

    The jumbo flying squid (Dosidicus gigas) population was surveyed with the help of Chinese squid jigging vessels off the Costa Rica Dome (4˚-11˚N, 90˚-100˚W) in 2009 and 2010. The daily catch of D. gigas in the two survey cruises ranged from 0 to 5.5 t and was mostly obtained from the areas bounded by 6˚-9˚N and 91˚-94˚W and by 6˚30´-7˚30´N and 96˚-97˚W. The sea surface temperature in the areas yielding the most catch ranged from 27.5 to 29℃. The sex ratio of the total catch was 3.75:1 (female:male). The mantle length of the squid ranged from 211 to 355 mm (male) and from 204 to 429 mm (female) with an average of 297.9 and 306.7 mm, respectively. In the relationship of the mantle length (mm) and body weight (g) of the squid, there was no significant dif-ference between sexes. The female and male were at a similar maturity, and most individuals are maturing or have matured with a few females being spent. The size (mantle length) and age at the first sexual maturity were 297 mm and 195 d in females, and less than 211 mm and 130 d in males, respectively. Most of the sampled stomachs (70.6%) had no food remains. The major preys of the squids were fish, cephalopods and crustaceans, with the most abundant Myctophum orientale and D. gigas. The preys in more than 65%of the non-empty sampled stomachs evidenced the cannibalism of D. gigas. The results improved current understanding of the fishery biology of D. gigas off the Costa Rica Dome, which may facilitate the assessment and management of relative fishery re-sources.

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

    Science.gov (United States)

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

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

  18. Fabrication of HTS SQUID Sensors for the Application to a High S/N Ratio Magnetocardiograph System

    International Nuclear Information System (INIS)

    YBCO do superconducting quantum interference device (SQUID) magnetometers based on bicrystal Josephson junctions on 10 mm x 10 mm SrTiO3 substrates have been fabricated. The pickup coil of the device was designed to have 16 parallel loops with 50-fm-wide lines. We could obtain optimised direct coupled YBCO SQUID magnetometer design with field sensitivity BNφ/ of 4.5 nT/φ0 and magnetic field noise BN of about 22 fT/Hz12/ with an I/f corner frequency of 2 Hz measured inside a magnetically shielded room. Preliminary results of magnetocardiograph measurement using the HTS SQUID magnetometers show signal to noise ratio of about 110, which is comparable to the quality of a commercial MCG system based on Nb-SQUIDs.

  19. A high-Tc SQUID micro-detector with a high performance magnetic shield for contaminant detection in industrial products

    International Nuclear Information System (INIS)

    A high-Tc superconducting quantum interference device (SQUID) system for the detection of magnetic foreign matter in industrial products was developed. There is a possibility that ultra-small metallic foreign matter has been accidentally mixed with industrial products such as lithium ion batteries. Metallic particles with outer dimensions less than 100 μm cannot be detected by conventional x-ray imaging. Therefore we developed a detection system based on a high-Tc SQUID microscope with a high performance magnetic shield. The use of SQUID microscopes with a 0.5 mm thick vacuum window was proposed. This design enables the SQUID to approach the object to be measured as close as 1 mm and enhances the sensitivity. A new magnetic shield with sleeves was carefully designed and built. As a result, we could successfully measure small particles sized 100 μm. This detection level was hard to achieve using a conventional x-ray detection method

  20. Baseline of organotin pollution in fishes, clams, shrimps, squids and crabs collected from the west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Jadhav, S.; Bhosale, D.; Bhosle, N.B.

    , crustaceans and molluscans are easily prone to organotins contamination. In view of this, a baseline monitoring study was conducted in order to establish the levels of organotins in edible marine fishes, bivalves, shrimps, squids and crabs collected from...

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

    International Nuclear Information System (INIS)

    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

  2. Stable isotopes on jumbo squid (Dosidicus gigas) beaks to esitmate its trophic positon: comparison between stomach contents and stable isotopes

    OpenAIRE

    Ruiz Cooley, R.I.; Markaida, U.; Gendron, Diane; Aguíñiga García, Sergio

    2006-01-01

    Stomach contents and carbon (C) and nitrogen (N) stable isotope analysis were used to evaluate trophic relationships of jumbo squid, Dosidicus gigas. Buccal masses, beaks and stomach contents of large and medium maturing-sized jumbo squid and muscle from its main prey, the myctophid Benthosema panamense, were collected in the Gulf of California, Mexico during 1996, 1997 and 1999. Both the quantified C and N-isotope ratios in muscle, and stomach content analysis revealed that larger-sized matu...

  3. Ultralow-field NMR on Room Temperature samples using a low TC Two-Stage DC SQUID

    OpenAIRE

    Piscitelli, Michele

    2010-01-01

    This thesis describes the development of low-field Nuclear Magnetic Resonance (NMR) systems based on Superconducting QUantum Interference Device (SQUID) detection for use on room temperature samples and presents initial test results using various liquid samples. The original proof of principle low-field SQUID NMR spectrometer consists of a cryogenic dipper probe designed for small liquid samples on the order of 100 μl, which is operated in a liquid-helium Dewar equipped with a simple μ-m...

  4. Scheme for the implementation of the optimal economical phase-covariant quantum cloning machine with SQUID qubits in cavity QED

    International Nuclear Information System (INIS)

    We propose a scheme to realize the optimal economical 1->2 phase-covariant quantum cloning machine (QCM) in 2 dimension with superconducting quantum interference device (SQUID) qubits in a microwave cavity. In our scheme, two-SQUID qubits are fixed into a microwave cavity by adiabatic passage method for their manipulation. Using this method, we can realize the optimal phase-covariant QCM only by one step

  5. Low-frequency noise in high-{Tc} superconductor Josephson junctions, SQUIDs, and magnetometers

    Energy Technology Data Exchange (ETDEWEB)

    Miklich, A.H.

    1994-05-01

    Design and performance of high-T{sub c} dc superconducting quantum interference devices (SQUEDs), junctions that comprise them, and magnetometers made from them are described, with attention to sources of 1/f noise. Biepitaxial junctions are found to have large levels of critical current fluctuations which make them unsuitable for low-noise SQUIDS; this suggests a poorly connected interface at the grain boundary junction. SQUIDs from bicrystal junctions have levels of critical current noise controllable using bias current reversal techniques which leave the noise white down to frequencies of a few Hz. A SQUID with an energy resolution of 1.5{times}10{sup {minus}30} J Hz{sup {minus}1} at 1 Hz is reported. Magnetometers in which a (9 mm){sup 2} pickup loop is directly coupled to a SQUID body have achieved field resolutions of 93 fT Hz{sup {minus}1/2} down to frequencies below I Hz, improving to 39 fT Hz{sup {minus}1/2} at 1 Hz with the addition of a 50mm-diameter single-turn flux transformer. Poor coupling to pickup loop makes it difficult to satisfy competing goals of high field resolution and small detector size necessary for multichannel biomagnetic imaging. Improved coupling is demonstrated by the use of multiturn-input-coil flux transformers, and a resolution of 35 fT Hz{sup {minus}1/2} in the white noise region is reported with a (10 mm){sup 2} pickup loop. However, additional 1/f noise from processed multilayer structures in the transformer limits the resolution at 1 Hz to 114 fT Hz{sup {minus}1/2}. High-T{sub c} SQUIDs exhibit additional 1/f noise when cooled in a nonzero static magnetic field because of additional flux vortices trapped in the film, with the noise power at 1 Hz typically increasing by a factor of 10--20 in a field of 0.05mT (0.5 G). Finally, a SQUID-based voltmeter with a resolution of 9.2 pV.Hz{sup {minus}1/2} at 10 Hz (24 pV Hz{sup {minus}1/2} at 1 Hz) is described.

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

    Energy Technology Data Exchange (ETDEWEB)

    Drung, Dietmar [Physikalisch-Technische Bundesanstalt (PTB), Abbestrasse 2-12, D-10587 Berlin (Germany); Hinnrichs, Colmar [Magnicon GbR, Wachtelweg 7, D-22869 Schenefeld (Germany); Barthelmess, Henry-Jobes [Magnicon GbR, Wachtelweg 7, D-22869 Schenefeld (Germany)

    2006-05-15

    User-friendly ultra-high-speed readout electronics for dc superconducting quantum interference devices (SQUIDs) are presented. To maximize the system bandwidth, the SQUID is directly read out without flux modulation. A composite preamplifier is used consisting of a slow dc amplifier in parallel with a fast ac amplifier. In this way, excellent dc precision and a high amplifier bandwidth of 50 MHz are achieved, simultaneously. A virtual 50 {omega} amplifier input resistance with negligible excess noise is realized by active shunting, i.e., by applying feedback from preamplifier output to input via a high resistance. The white voltage and current noise levels are 0.33 nV Hz{sup -1} and 2.6 pA Hz{sup -1/2}, respectively. The electronics is fully computer controlled via a microcontroller integrated into the flux-locked loop (FLL) board. Easy-to-use software makes the various electronic settings accessible. A wide bias voltage range of 1.3 mV enables the readout of series SQUID arrays. Furthermore, additional current sources allow the operation of two-stage SQUIDs or transition edge sensors. The electronics was tested using various SQUIDs with input inductances between 30 nH and 1.5 {mu}H. Typically, the maximum FLL bandwidth was 20 MHz, which is close to the theoretical limit given by transmission line delay within the FLL. Slew rates of up to 4.6 {phi}{sub 0} {mu}s{sup -1} were achieved with series SQUID arrays. Current noise levels as low as 0.47 pA Hz{sup -1/2} and coupled energy sensitivities between 90 h and 500 h were measured at 4.2 K, where h is the Planck constant. The noise did not degrade when the system bandwidth was increased to the maximum value of about 20 MHz. With a two-stage set-up, intrinsic white energy sensitivities of 30 h and 2.3 h were measured at 4.2 and 0.3 K, respectively.

  7. Studies on the effect of low dose gamma irradiation on the chemical, microbial quality and shelf life of squid

    International Nuclear Information System (INIS)

    The present investigation was carried out to study the combined effect of low dose gamma irradiation (1, 3 and 5 kGy) and storage at refrigeration (+4℃) and frozen (-18℃) temperatures, on the shelf life extension of fresh squid. The study was based on microbiological and physico-chemical changes occurring in the squid samples. The biochemical parameters such as total volatile base nitrogen and trimethyl amine nitrogen values for irradiated squid samples were significantly lower than non-irradiated samples at both storage temperatures and the rate of decrease was more pronounced in samples irradiated at the higher dose of 3 and 5 kGy (p<0.05). pH values of squid samples were affected by both irradiation dose and storage temperature (p<0.05). Total microbial load for non- irradiated (control) squid samples were higher than the respective irradiated samples at both storage temperatures. The results revealed that the combination of irradiation and low temperature storage resulted in a significant reduction of microbial growth and extend the shelf life of squid at refrigeration and frozen temperature to about 12 and 90 days respectively. (author)

  8. Plerocercoids of Nybelinia surmenicola (Cestoda: Tentacularidae) in Squids, Todarodes pacificus, from East Sea, the Republic of Korea.

    Science.gov (United States)

    Lee, Joon Yup; Kim, Ji Woon; Park, Gab Man

    2016-04-01

    A visceral helminth of the squid, Todarodes pacificus, is reported from the East Sea, the Republic of Korea. Total 39 squid samples were purchased from a fish market in Jumunjin-eup, Gangneung-si (City) from August 2014 to July 2015 and were examined for helminth parasites with naked eyes and under a stereomicroscope after opening the abdominal cavity with a pair of scissors. Whitish larval worms were mainly found in the stomach and abdominal cavity of the squid. They were detected in 25 (64.1%) out of 39 squids examined, and the infection density was 7 larvae per infected squid. Spatula-shaped larvae were 8.2×2.0 mm in average size, round to slightly flattened anteriorly, with round hatching posteriorly, and had characteristic 4 tentacles with numerous hooklets in the scolex. The larvae were identified as the plerocercoid stage of Nybelinia surmenicola by their morphological features. This finding represents a new host record and the first report of N. surmenicola infection in T. pacificus squids from the east coast of Korea. PMID:27180583

  9. Ultra-sensitive sensors for weak electromagnetic fields using high-Tc SQUIDS for biomagnetism, NDE, and corrosion currents

    International Nuclear Information System (INIS)

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The research has directly contributed to a new DOE supported project, three patents (one granted and two submitted), and several potential opportunities for new program funding at the Laboratory. The authors report significant developments extending from basic understanding of and fabrication techniques for high critical-temperature (high-Tc) SQUID devices to the development of high-level applications such as the SQUID Microscope. The development of ramp edge geometry and silver-doped YBa2Cu3O7-x (YBCO) electrodes has tremendously improved the performance of high-Tc SQUIDS. Recent experiments have proven and quantified the LANL-patented superconducting imaging plane gradiometry concept. A SQUID microscope, developed largely under this project, has recently acquired data that demonstrated exceptional sensitivity and resolution. New techniques for background noise suppression, needed to use the extraordinarily sensitive SQUID sensors in unshielded environments, have also been developed. Finally, initial investigations to use SQUIDs in a basic physics experiment to measure the electric dipole moment of the neutron were very successful

  10. Detection of ruptures in prestressed steel rods for concrete structures using HTc-SQUIDs

    International Nuclear Information System (INIS)

    Prestressed steel reinforcement is commonly used to enhance the stability of concrete structures like bridges and buildings because the concrete alone is not able to withstand large tensile stresses. Reinforced constructions can be lighter and may have longer spans. The reinforcement usually consists of jacketed steel bundles each of which is made of about 5 to 50 rods. The occurrence of cracks and ruptures in these rods especially due to hydrogen embrittlement may eventually lead to a failure of the structure with possibly disastrous consequences. Therefore, a method for nondestructively testing the state of rods imbedded in the concrete is needed. In this communication we present a method relying on the magnetic stray flux due to the rupture. As a first step the magnetic signal is detected by normal search coils which are inductively coupled to a rf SQUID. To enhance the sensitivity of this method, the SQUID itself will ultimately have to be used as a sensor. (orig.)

  11. Magnetic characterization by SQUID and FMR of a biocompatible ferrofluid based on Fe3O4

    International Nuclear Information System (INIS)

    Biocompatible superparamagnetic iron oxide nanoparticles of magnetite coated with dextran were magnetically characterized using the techniques of SQUID (superconducting quantum interference device) magnetometry and ferromagnetic resonance (FMR). The SQUID magnetometry characterization was performed by isothermal measurements under applied magnetic field using the methods of zero-field-cooling (ZFC) and field-cooling (FC). The magnetic behavior of the nanoparticles indicated their superparamagnetic nature and it was assumed that they consisted exclusively of monodomains. The transition to a blocked state was observed at the temperature TB = (43 ± 1) K for frozen ferrofluid and at (52 ± 1) K for the lyophilized ferrofluid samples. The FMR analysis showed that the derivative peak-to-peak linewidth (ΔHPP), gyromagnetic factor (g), number of spins (NS), and spin-spin relaxation time (T2) were strongly dependent on both temperature and super-exchange interaction. This information is important for possible nanotechnological applications, mainly those which are strongly dependent on the magnetic parameters.

  12. All-planar SQUIDs and pickup coils for combined MEG and MRI

    International Nuclear Information System (INIS)

    Flux trapping and random flux movement are common problems in superconducting thin-film devices. Ultrasensitive magnetic field sensors based on superconducting quantum interference devices (SQUIDs) coupled to large pickup coils are especially vulnerable to strong external fields. The issue has become particularly relevant with the introduction of SQUID-based ultra-low-field (ULF) nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) techniques. In this paper, we study the constraints of thin-film-based magnetometers and gradiometers as exposed to magnetic field sequences of ULF MRI. In particular, we address issues such as response recovery, transient noise, magnetization and behaviour under shielded room conditions after prepolarization. As a result, we demonstrate sensors that are suitable for a combined multi-channel magnetoencephalography (MEG) and MRI imaging system.

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

    DEFF Research Database (Denmark)

    Sørensen, O. H.

    1976-01-01

    omegatau. It is, however, also shown that it is nontrivial to ext ract its magnitude from experiments based on the behavior of the ac SQUID, and that the recently published observations using this technique must be reinterpreted. Journal of Applied Physics is copyrighted by The American Institute of......The properties of the ac SQUID magnetometer has been analyzed. The results are valid in the low-inductance low-critical-current regime, where the Lri0 producted is belowthe value at which the relation between the enclosed and externally applied magnetic dc flux becomes reentrant. The effects of the...... constriuctively with the result that the optimal response occurs at a definite and finite value of omegatau. If omegatau is increased beyond this optimal value the weak link behavior is dominated by the Ohmic current channel implying that only if the shunt conductance contains a term depending on the...

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

    Science.gov (United States)

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

    2014-04-01

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

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

    International Nuclear Information System (INIS)

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

  16. Chemical and Functional Characterization of Sarcoplasmic Proteins from Giant Squid (Dosidicus gigas Mantle

    Directory of Open Access Journals (Sweden)

    Rosa Linda Lopez-Enriquez

    2015-01-01

    Full Text Available Modification of pH and NaCl concentration changed the physicochemical properties of sarcoplasmic proteins (SP from jumbo squid mantle and consequently their functional properties. Better results of emulsifying activity index (EAI and foam capacity (FC were exhibited at pH 11 in NaCl absence due to higher solubility. But better emulsifying stability index (ESI was obtained at pH 11 in 0.5 M NaCl, while, foaming stability (FS was better at pH near to isoelectric point (pI. These results suggest that SP from jumbo squid may be a promising ingredient, whose functional properties can be manipulated by changing pH and NaCl concentration.

  17. Design and optimization of dc SQUIDs fabricated using a simplified four-level process

    International Nuclear Information System (INIS)

    This paper describes an optimization procedure which we have used to design two types of ultralow noise dc Superconducting Quantum Interference Devices (SQUIDs) with integrated flux coupling circuits, a magnetometer and a gradiometer. Essential to this design approach is the reduction of the parasitic capacitance, the choice of a layout which moves the input coil resonances well away from the desired operating frequency of the SQUID, and the proper damping of these resonances. We show that both the microwave and LC resonances can be damped in a nearly noise free manner by placing an RC shunt in parallel with the input coil. This leads to smooth voltage-flux modulation characteristics and significantly improved noise performance. A simple, four-level Nb/SixNy/Nb Josephson junction technology is described for device fabrication

  18. Analysis of a Josephson junction noise thermometer with a DC-SQUID preamplifier

    International Nuclear Information System (INIS)

    A Josephson junction noise thermometer directly coupled to a low noise preamplifier is analyzed. The absolute determination of temperature is disturbed by several effects: mixed down noise, additive noise, post-detection filter, etc. The analysis presented here takes these error sources into account, and the accuracy of the thermometer is estimated. The analysis shows that, exactly like an rf-biased R-SQUID noise thermometer, a directly coupled noise thermometer is ultimately limited by the noise temperature of the preamplifier. Since the noise temperature of a state-of-the-art dc SQUID amplifier is excellent, sufficiently low uncertainty (less than 1%) can be obtained, even below 1 mK. (orig.)

  19. All-planar SQUIDs and pickup coils for combined MEG and MRI

    Energy Technology Data Exchange (ETDEWEB)

    Luomahaara, J; Kiviranta, M; Groenberg, L; Hassel, J [VTT Technical Research Centre of Finland, PO BOX 1000, 02044 VTT (Finland); Vesanen, P T; Nieminen, J O; Dabek, J; Zevenhoven, C J; Ilmoniemi, R J [Department of Biomedical Engineering and Computational Science, Aalto University, PO BOX 12200, 00076 Aalto (Finland); Penttilae, J [Aivon Oy, Tietotie 3, 02150 Espoo (Finland); Simola, J, E-mail: juho.luomahaara@vtt.fi [Elekta Oy, PO Box 34, 00531 Helsinki (Finland)

    2011-07-15

    Flux trapping and random flux movement are common problems in superconducting thin-film devices. Ultrasensitive magnetic field sensors based on superconducting quantum interference devices (SQUIDs) coupled to large pickup coils are especially vulnerable to strong external fields. The issue has become particularly relevant with the introduction of SQUID-based ultra-low-field (ULF) nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) techniques. In this paper, we study the constraints of thin-film-based magnetometers and gradiometers as exposed to magnetic field sequences of ULF MRI. In particular, we address issues such as response recovery, transient noise, magnetization and behaviour under shielded room conditions after prepolarization. As a result, we demonstrate sensors that are suitable for a combined multi-channel magnetoencephalography (MEG) and MRI imaging system.

  20. High-T{sub c} SQUID gradiometer system for magnetocardiography in an unshielded environment

    Energy Technology Data Exchange (ETDEWEB)

    Liao, S H [Department of Physics, National Taiwan Normal University, Taipen 116, Taiwan (China); Hsu, S C [Institute of Electro-optical Science and Technology, National Taiwan Normal University, Taipei 116, Taiwan (China); Lin, C C [Institute of Electro-optical Science and Technology, National Taiwan Normal University, Taipei 116, Taiwan (China); Horng, H E [Department of Physics, National Taiwan Normal University, Taipen 116, Taiwan (China); Chen, J C [Department of Physics, National Taiwan University, Taipei 106, Taiwan (China); Chen, M J [Department of Physics, National Taiwan University, Taipei 106, Taiwan (China); Wu, C H [Department of Physics, National Taiwan University, Taipei 106, Taiwan (China); Yang, H C [Institute of Electro-optical Science and Technology, National Taiwan Normal University, Taipei 116, Taiwan (China)

    2003-12-01

    We set up an electronic gradiometer for magnetocardiography (MCG) in an unshielded environment. The electronically balanced gradiometer consists of high-temperature radio-frequency superconducting quantum interference device (rf SQUID) magnetometers. The rf SQUID magnetometers are arranged to form the electronic first-order, four-vector gradiometer, or second-order gradiometer. The output of the MCG signal was filtered by a band pass (1-30 Hz) and power line filters. We can reduce the noise to {approx}1 pT Hz{sup -1/2} at 1 Hz for second-order or four-vector gradiometers. Two-dimensional MCG imaging is demonstrated. The results are discussed with data measured in the moderate magnetically shielded environment.

  1. Complete genome sequence of the mitochondrial DNA of the sparkling enope squid, Watasenia scintillans.

    Science.gov (United States)

    Hayashi, Keiko; Kawai, Yuri L; Yura, Kei; Yoshida, Masa-Aki; Ogura, Atsushi; Hata, Kenichiro; Nakabayashi, Kazuhiko; Okamura, Kohji

    2016-05-01

    The sparkling enope squid, Watasenia scintillans, is a deep-sea mollusk inhabiting the western part of the Pacific Ocean. It has the peculiar ability to illuminate its body without the involvement of other organisms. In this study, we extracted the brain DNA from a single squid female caught in the Japan Sea and determined the complete genome sequence of its mitochondrial DNA using the Illumina sequencing platform. The circular sequence is 20,089 bp in length. Using the next-generation sequencing data, we also estimated the mean copy number of mitochondria per cell in the brain to be 108 by comparing the depths of the read data in the nuclear and mitochondrial genomes. The haploid genome size was calculated to be 4.78 Gb. Six heteroplasmy sites were also identified, together with their allele frequencies, in this individual. Our methodology is shown to be useful in mitochondrion-related studies. PMID:25329271

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

    Science.gov (United States)

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

    2016-03-01

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

  3. Low-frequency noise of dc SQUID magnetometers having slotted structure along the grain boundary junction

    International Nuclear Information System (INIS)

    In order to operate high-Tc SQUID magnetometers in an environment with no or weak magnetic shielding, we incorporated slots along the wide (3 mm) grain boundary junction in the pickup coil and the flux dam of direct-coupled SQUID magnetometers. It was confirmed that the slots formed along the wide grain boundary junction suppressed vortex motion and prevented a large increase in low-frequency noise. When we applied external fields above a threshold value of the flux dam after zero-field cooling, the flux-locked-loop output fluctuated, and the low-frequency field noise Bn increased but became stable after a time. The relaxation time after field application was longer for higher fields. A slight increase in the low-frequency noise remained, which was attributed to the fluctuation of the flux trapped in the slots having grain boundaries. (author)

  4. SQUID magnetometry for the cryoEDM experiment-Tests at LSBB

    International Nuclear Information System (INIS)

    High precision magnetometry is an essential requirement of the cryoEDM experiment at the Institut Laue-Langevin, Grenoble. We have developed a SQUID system for this purpose, however tests done in Oxford have been limited by the noisy electromagnetic environment inside our laboratory, therefore we have tested a smaller version of our prototype system in the very low noise environment at LSBB, Rustrel, France. We have studied the crosstalk between an array of parallel pick-up loops-where the field generated by a current in one loop is detected by the others. We monitored the magnetic field in the LSBB for over twelve hours; and after correcting these data for SQUID resets, and crosstalk, we compare it to the published values from nearby geomagnetic observatories. We have also measured the noise spectrum of our system and studied the effect that heating one of the pick-up loops into its conducting state has on the other, parallel loops.

  5. Multi-Channel Magnetocardiogardiography System Based on Low-Tc SQUIDs in an Unshielded Environment

    Science.gov (United States)

    Kong, Xiangyan; Zhang, Shulin; Wang, Yongliang; Zeng, Jia; Xie, Xiaoming

    Magnetocardiography (MCG) using superconducting quantum interference devices (SQUIDs) is a new medical diagnostic tool measuring biomagnetic signals that are generated by the electrical activity of the human heart. This technique is completely passive, contactless, and it has an advantage in the early diagnosis of heart diseases. We developed the first unshielded four-channel MCG system based on low-Tc DC SQUIDs in China. Instead of using a costly magnetically shielded room, the environmental noise suppression was realized by using second-order gradiometers and three-axis reference magnetometer. The measured magnetic field resolution of the system is better than 1 pT, and multi-cycle human heart signals can be recorded directly. Also, with the infrared positioning system, 48 points data collection can be realized by moving the non-magnetic bed nine times.

  6. Design and performance of the ADMX SQUID-based microwave receiver

    CERN Document Server

    Asztalos, S J; Hagmann, C; Kinion, D; van Bibber, K; Hotz, M; Rosenberg, L J; Rybka, G; Wagner, A; Hoskins, J; Martin, C; Sullivan, N S; Tanner, D B; Bradley, R; Clarke, John

    2011-01-01

    The Axion Dark Matter eXperiment (ADMX) was designed to detect ultra-weakly interacting relic axion particles by searching for their conversion to microwave photons in a resonant cavity positioned in a strong magnetic field. Given the extremely low expected axion-photon conversion power we have designed, built and operated a microwave receiver based on a Superconducting QUantum Interference Device (SQUID). We describe the ADMX receiver in detail as well as the analysis of narrow band microwave signals. We demonstrate the sustained use of a SQUID amplifier operating between 812 and 860 MHz with a noise temperature of 1 K. The receiver has a noise equivalent power of 1.1x10^-24 W/sqrt(Hz) in the band of operation for an integration time of 1.8x10^3 s.

  7. SQUID-based microtesla MRI for in vivo relaxometry of the human brain

    CERN Document Server

    Zotev, V S; Matlashov, A N; Savukov, I M; Owens, T; Espy, M A

    2008-01-01

    SQUID-based MRI (magnetic resonance imaging) at microtesla fields has developed significantly over the past few years. Here we describe application of this method for magnetic relaxation measurements in the living human brain. We report values of the longitudinal relaxation time T1 for brain tissues, measured in vivo for the first time at microtesla fields. The experiments were performed at 46 microtesla field using a seven-channel SQUID system designed for microtesla MRI and MEG. Values of T1, measured for different tissues at this field, are found to be close (within 5%) to the corresponding values of the transverse relaxation time T2 at the same field. Implications of this result for imaging contrast in microtesla MRI are discussed.

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

    Science.gov (United States)

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

    2016-07-01

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

  9. A thin-film second-order gradiometer with integrated dc-SQUID

    Science.gov (United States)

    Carelli, P.; Castellano, M. G.; Chiaventi, L.; Leoni, R.; Cirillo, M.; Modena, I.

    1993-09-01

    We have fabricated and characterized a superconducting planar gradiometer sensitive to the second-order spatial derivative of the magnetic field. Our device has been patterned on a 12.8×12.8 mm silicon chip on which the sensitive area of the gradiometer and the SQUID inductance are generated by the same four 0.5-mm-square holes. We measured the sensitivity both in flux-locked-loop (FLL) and in open-loop mode. With the second method we used another dc-SQUID as amplifier and in this case we obtained the best noise performance. The gradiometer sensitivity was 18 fT/cm2 √Hz. The magnetic isoflux line distribution generated by a dipolar source was measured by the gradiometer in FLL mode.

  10. Systematic value of the ultrastructure of the sucker surface in the squid family Mastigoteuthidae (Mollusca: Cephalopoda)

    OpenAIRE

    Salcedo-Vargas, Mario Alejandro

    1995-01-01

    The ultrastructure of the sucker surface is described and its systematic value for mastigoteuthid squids, which bear minute suckers, is considered. An introduction to sucker terms is given and a redefinition of these terms is attempted. Using scanning electron microscopic data, two genera and four subgenera of Mastigoteuthidae from the Northwest Pacific are distinguished. The presence of “cushions” in the sucker is discussed and considered as a character important for understanding adaptation...

  11. Artificial neural network based on SQUIDs: demonstration of network training and operation

    International Nuclear Information System (INIS)

    We propose a scheme for the realization of artificial neural networks based on superconducting quantum interference devices (SQUIDs). In order to demonstrate the operation of this scheme we designed and successfully tested a small network that implements an XOR gate and is trained by means of examples. The proposed scheme can be particularly convenient as support for superconducting applications such as detectors for astrophysics, high energy experiments, medicine imaging and so on. (paper)

  12. Infiltration of chitin by protein coacervates defines the squid beak mechanical gradient

    OpenAIRE

    Y. Tan; Hoon, S; Guerette, PA; Wei, W; Ghadban, A; Hao, C; Miserez, A; Waite, JH

    2015-01-01

    © 2015 Nature America, Inc. All rights reserved. The beak of the jumbo squid Dosidicus gigas is a fascinating example of how seamlessly nature builds with mechanically mismatched materials. A 200-fold stiffness gradient begins in the hydrated chitin of the soft beak base and gradually increases to maximum stiffness in the dehydrated distal rostrum. Here, we combined RNA-Seq and proteomics to show that the beak contains two protein families. One family consists of chitin-binding proteins (DgCB...

  13. Lack of genetic differentiation among size groups of jumbo squid (Dosidicus gigas)

    OpenAIRE

    E Sandoval-Castellanos; M Uribe-Alcocer; P Díaz-Jaimes

    2009-01-01

    The population structure of the jumbo squid (Dosidicus gigas) is complex, containing several cohorts and three groups defined by their size (small, medium, and large) and by differences in maturation, growth, and life span. Several authors have indicated the possibility of such groups representing discrete genetic units even at level subspecies or species in statu nascendi. Genetic divergence was tested in samples from the Gulf of California (Mexico) and Peruvian Sea by estimation of populati...

  14. Ecology and Trophic Interactions of Jumbo Squid (Dosidicus gigas) in the California Current Ecosystem

    OpenAIRE

    Gilly, William; Field, John

    2012-01-01

    Humboldt squid have recently demonstrated a range expansion into the waters off California from the previous northern extent of their range in Mexico. In this new environment, we expected the vertical and horizontal migratory behavior and the diet to be generally similar those previously documented in Mexico. However, we also expected significant differences in diet and reproductive activity, with potentially great impacts on ecosystems in the California Current System. In particular, consump...

  15. Physico-chemical and film forming properties of giant squid (Dosidicus gigas) gelatin

    OpenAIRE

    Giménez, B.; Gómez Estaca, Joaquín; Alemán, A.; Gómez Guillén, M. C.; Montero García, Pilar

    2009-01-01

    Giant squid (Dosidicus gigas) inner and outer tunics were subjected to hydrolysis with pepsin prior to gelatin extraction (G1 gelatin) by a mild-acid procedure. Furthermore, a second gelatin extraction (G2 gelatin) was done using the collagenous residues that remained from the first extraction. Pepsin allows the collagen solubilisation and the extraction yield to increase by yielding extracts high in α-chains. G1 exhibited good gel forming ability but G2 showed poor viscoelastic behaviour and...

  16. Invasive range expansion by the Humboldt squid, Dosidicus gigas, in the eastern North Pacific

    OpenAIRE

    Zeidberg, Louis D.; Robison, Bruce H.

    2007-01-01

    A unique 16-year time series of deep video surveys in Monterey Bay reveals that the Humboldt squid, Dosidicus gigas, has substantially expanded its perennial geographic range in the eastern North Pacific by invading the waters off central California. This sustained range expansion coincides with changes in climate-linked oceanographic conditions and a reduction in competing top predators. It is also coincident with a decline in the abundance of Pacific hake, the most important commercial grou...

  17. Jumbo Squid (Dosidicus gigas) in situ Target Strength measurements in Northwest Mexico

    OpenAIRE

    Villalobos, H.; Manini-Ramos, F.; Salinas-Zavala, C.; Brehmer, Patrice

    2013-01-01

    In order to convert acoustic abundance indexes into biomass is essential to establish the relationship between squid size dorsal mantle length (DML) and acoustic Target Strength (TS). We had carried out in situ measurement in 2012 off Baja California on Dosidicus gigas. For both frequencies, we found significant differences between modes of measured and predicted TS distributions, 6 and 11 dB for 120 and 38 kHz, respectively. It is known that TS varies with several factors, including echosoun...

  18. A noise feedback least-mean-square algorithm of data processing for SQUID-based magnetocardiography

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, X M [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China); Tian, Y [Department of Physics, University of Science and Technology of China, Hefei, Anhui Province 230026 (China); Zhao, S P [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China); Chen, G H [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China); Yang, Q S [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China)

    2005-08-01

    We present a modified normalized least-mean-square algorithm for SQUID-based magnetocardiography data processing with a new error function, in which the instantaneous signal component represented approximately by an average of near past error data has been eliminated. In this way, the rebounds of the weight vector W from its optimal value in parameter space due to the signal component can be well avoided.

  19. Analysis of metal catalyst content in magnetically filtered SWCNTs by SQUID magnetometry

    Czech Academy of Sciences Publication Activity Database

    Pacáková, Barbara; Komínková, Zuzana; Vejpravová, Jana; Kalbáč, Martin

    2015-01-01

    Roč. 50, č. 6 (2015), s. 2544-2553. ISSN 0022-2461 R&D Projects: GA ČR GAP204/10/1677 Institutional support: RVO:68378271 ; RVO:61388955 Keywords : single-wall carbon nanotubes * nanoparticles * magnetic filtration * SQUID Subject RIV: BM - Solid Matter Physics ; Magnetism; CF - Physical ; Theoretical Chemistry (UFCH-W) Impact factor: 2.371, year: 2014

  20. Chitinolytic Bacteria-Assisted Conversion of Squid Pen and Its Effect on Dyes and Pigments Adsorption

    Directory of Open Access Journals (Sweden)

    Tzu-Wen Liang

    2015-07-01

    Full Text Available The aim of this work was to produce chitosanase by fermenting from squid pen, and recover the fermented squid pen for dye removal by adsorption. One chitosanase induced from squid pen powder (SPP-containing medium by Bacillus cereus TKU034 was purified in high purification fold (441 and high yield of activity recovery (51% by ammonium sulfate precipitation and combined column chromatography. The SDS-PAGE results showed its molecular mass to be around 43 kDa. The TKU034 chitosanase used for the chitooligomers preparation was studied. The enzyme products revealed that the chitosanase could degrade chitosan with various degrees of polymerization, ranging from 3 to 9, as well as the chitosanase in an endolytic manner. Besides, the fermented SPP was recovered and displayed a better adsorption rate (up to 99.5% for the disperse dyes (red, yellow, blue, and black than the water-soluble food colorants, Allura Red AC (R40 and Tartrazine (Y4. The adsorbed R40 on the unfermented SPP and the fermented SPP was eluted by distilled water and 1 M NaOH to confirm the dye adsorption mechanism. The fermented SPP had a slightly higher adsorption capacity than the unfermented, and elution of the dye from the fermented SPP was easier than from the unfermented. The main dye adsorption mechanism of fermented SPP was physical adsorption, while the adsorption mechanism of unfermented SPP was chemical adsorption.