The Experts below are selected from a list of 258 Experts worldwide ranked by ideXlab platform
T Kiyoshi - One of the best experts on this subject based on the ideXlab platform.
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improving the properties of gdbco Magnetic Lenses by adopting a new design and resin impregnation
Superconductor Science and Technology, 2013Co-Authors: Z Y Zhang, S Matsumoto, T Kiyoshi, Ryo TeranishiAbstract:High field concentration and magnetothermal stability are critical considerations when designing and fabricating Magnetic Lenses made from a stack of bulk high-temperature superconducting (HTS) material. In a previous study, we investigated a GdBCO Magnetic lens for use as a compact high-field superconducting magnet, but it cracked due to a high flux jump. In the present study, we investigate the Magnetic performance of an improved GdBCO lens. This new lens had almost the same dimensions as the previous one, but it was impregnated with epoxy resin to prevent it breaking. The impregnated lens exhibited superior stability and Magnetic properties, making it promising for use in a compact magnet system. A maximum field of 13 T was obtained at 20 K with no flux jump.
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Magnetic field, temperature and mechanical crack performance of a GdBCO Magnetic lens
Superconductor Science and Technology, 2012Co-Authors: Z Y Zhang, Ryo Teranishi, Shinji Matsumoto, T KiyoshiAbstract:Magnetic field concentration by using the diamagnetism of a superconductor is a novel technique that has been experimentally demonstrated in Magnetic Lenses. A Magnetic lens consists of a hollow superconductor cylinder with a tapered inner diameter within which the Magnetic flux is concentrated by diamagnetism. Magnetic Lenses are very promising for use in compact high Magnetic field systems. However, Magnetic Lenses with large inner diameters are required to facilitate sample access during use. In this study, an optimized GdBaCuO Magnetic lens with large inner and outer diameters was designed and its performance was investigated in liquid nitrogen, liquid helium, and a cryocooler-cooled cryostat. A lens with an inner diameter of 12 mm was constructed by stacking three specially machined GdBaCuO bulk pieces. This Magnetic lens cracked due to the large flux jump that occurred when the concentrated field of the Magnetic lens exceeded 10 T at 4.2 K. The cracked lens was subsequently impregnated with epoxy resin. A concentrated field of 12.42 T was realized when the background field was 8 T at 20 K and no flux jumps occurred. This result demonstrates that this GdBCO Magnetic lens is promising for use in compact superconducting magnet systems.
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Magnetic Lenses using different mgb 2 bulk superconductors
Superconductor Science and Technology, 2012Co-Authors: Z Y Zhang, S Choi, S Matsumoto, R Teranishi, G Giunchi, Figini A Albisetti, T KiyoshiAbstract:A Magnetic lens allows the concentration of Magnetic fields using the diamagnetism of superconductors. The important features of the Magnetic lens are a tapered inner diameter from which the Magnetic flux is extruded and a slit to suppress the circumference current that shields the Magnetic flux. This concept was experimentally confirmed through the use of GdBaCuO bulks and a stack of NbTi/Nb/Cu sheets. We refer to this arrangement as a Magnetic lens.The Mg-reactive liquid infiltration (Mg-RLI) process developed by Edison SpA is suitable for the production of large and high-density MgB2 bulks. Three MgB2 bulk Magnetic Lenses, each with a different microstructure, were fabricated following the Mg-RLI process. The properties of the MgB2 Magnetic Lenses were measured in a cryocooler system as well as in liquid helium. The results confirmed that the MgB2 bulk Magnetic Lenses could concentrate a Magnetic field and that their field concentration properties were greatly affected by the temperature and the external field. In addition, the microstructure of the MgB2 bulk also had an influence on the Magnetic properties at different external fields. The results indicated that the MgB2 lens might be utilized as a field amplifier in intermediate fields.
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comparison of different configurations of nbti Magnetic Lenses
Superconductor Science and Technology, 2011Co-Authors: Z Y Zhang, S Choi, S Matsumoto, T Kiyoshi, Ryo TeranishiAbstract:Magnetic Lenses are new devices that concentrate Magnetic flux by using the diamagnetism of superconductors. Magnetic Lenses of two types made from NbTi sheets were constructed; measurements were made on them and they were systematically studied. Type A was constructed by stacking NbTi rings that had identical outer diameters and increasing inner diameters to form a hollow cone. Each ring had a slit to suppress the circumference current. Three construction methods for type A were tested: the rings were stacked with their slits aligned but with no insulation between the rings (A-1), with their slits aligned and with insulation between the rings (A-2), and with their slits in different positions and with insulation between the rings (A-3). For type B, sheets were rolled into hollow cones. Three identical cones were stacked to form a lens (B-1) and a single cone was used as a reference lens (B-2). The Lenses were assembled in a cryocooler-cooled cryostat with a NbTi magnet. The quenching behavior, concentration ratio, hysteresis, and decay behavior were measured. Because of its larger dimensions, type B had a larger concentration ratio (2.49 for B-1) than type A (1.87 for A-1). Both Lenses (types A and B-1) were quenched when the concentrated flux density reached about 0.64 T. The results suggest that quenching was caused by the NbTi sheet itself.
A S A Alamir - One of the best experts on this subject based on the ideXlab platform.
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radial and spiral distortion of Magnetic Lenses with fields of the form b z αzn
Optik, 2009Co-Authors: A S A AlamirAbstract:Abstract Both radial and spiral distortion of Magnetic lens with the field distribution in the form B(z)αzn are analyzed by means of Scherzer's formula. To estimate the performance of the image in electron microscope the dimensionless quality factors (F.Z. Marai, T. Mulvey, Sherzer's formula and the correction of spiral distortion in the electron microscope, Ultramicroscopy 2 (1977) 187–192.), for both radial and spiral distortion is calculated. The results have been compared with different projector Lenses.
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Magnetic Lenses performance with fields of the form B(Z)∝Zn
Optik, 2009Co-Authors: A S A AlamirAbstract:Abstract Performance of Magnetic Lenses with fields of the form B ( z )∝ Z n was studied. To compare the performance of different objective Lenses the results are presented in W. Tretner's [Existenzbereiche rotations symmetrischer Elektronenlinsen, Optik 16 (1959) 155–184] form.
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on the optical properties of monopole multipole Magnetic Lenses
Optik, 2005Co-Authors: A S A AlamirAbstract:Abstract In this paper the spherical and chromatic aberration coefficients for the theoretical model B ( Z ) = B 0 ( a / Z ) n , which represented the multipole Magnetic Lenses, were calculated to express the magnitude analytically. The results are presented in a Tretner's (Optik 16 (1959) 155) form, which is particularly suited to the determination of Lenses of optimum performance.
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on the chromatic aberration of Magnetic Lenses with a field distribution in the form of an inverse power low b z z n
Optik, 2004Co-Authors: A S A AlamirAbstract:Summary The chromatic aberration of Magnetic Lenses with the field distribution in the forms of inverse law have been studied by analytical and digital methods. These aberrations can be expressed in terms of Bessel function of fraction order. Analytical expressions for chromatic aberration coefficients of the spherical field model, which is useful for the study of single-pole Magnetic Lenses, are given.
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On the chromatic aberration of Magnetic Lenses with a field distribution in the form of an inverse power low (B(z) ∝ z–n)
Optik, 2004Co-Authors: A S A AlamirAbstract:Summary The chromatic aberration of Magnetic Lenses with the field distribution in the forms of inverse law have been studied by analytical and digital methods. These aberrations can be expressed in terms of Bessel function of fraction order. Analytical expressions for chromatic aberration coefficients of the spherical field model, which is useful for the study of single-pole Magnetic Lenses, are given.
Jan G Korvink - One of the best experts on this subject based on the ideXlab platform.
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Magnetic lenz Lenses improve the limit of detection in nuclear Magnetic resonance
PLOS ONE, 2017Co-Authors: Jan G Korvink, Nils Spengler, Peter T While, Markus Meissner, Ulrike WallrabeAbstract:A high NMR detection sensitivity is indispensable when dealing with mass and volume-limited samples, or whenever a high spatial resolution is required. The use of miniaturised RF coils is a proven way to increase sensitivity, but situations may arise where space restrictions could prevent the use of a small resonant coil, e.g., in the interior of the smallest practicable micro-coils. We present the use of Magnetic Lenses, denoted as Lenz Lenses due to their working principle, to focus the Magnetic flux of an RF coil into a smaller volume and thereby locally enhance the sensitivity of the NMR experiment—at the expense of the total sensitive volume. Besides focusing, such Lenses facilitate re-guiding or re-shaping of Magnetic fields much like optical Lenses do with light beams. For the first time we experimentally demonstrate the use of Lenz Lenses in Magnetic resonance and provide a compact mathematical description of the working principle. Through simulations we show that optimal arrangements can be found.
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Magnetic flux tailoring through lenz Lenses in toroidal diamond indenter cells a new pathway to high pressure nuclear Magnetic resonance
arXiv: Instrumentation and Detectors, 2017Co-Authors: Thomas Meier, Nan Wang, Dario Mager, Jan G Korvink, Sylvain Petigirard, Leonid DubrovinskyAbstract:A new pathway to nuclear Magnetic resonance spectroscopy in high pressure diamond anvil cells is introduced, using inductively coupled broadband passive electro-Magnetic Lenses to locally amplify the Magnetic flux at the isolated sample, leading to an increase in sensitivity. The Lenses are adopted for the geometrical restrictions imposed by a toroidal diamond indenter cell, and yield high signal-to-noise ratios at pressures as high as 72 GPa, at initial sample volumes of only 230 pl. The corresponding levels of detection, LODt, are found to be up to four orders of magnitude lower compared to formerly used solenoidal micro-coils in diamond anvil cells, as shown by Proton-NMR measurements on paraffin oil. This approach opens up the field of ultra-high pressure sciences for one of the most versatile spectroscopic methods available in a pressure range unprecedended up to now.
Z Y Zhang - One of the best experts on this subject based on the ideXlab platform.
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improving the properties of gdbco Magnetic Lenses by adopting a new design and resin impregnation
Superconductor Science and Technology, 2013Co-Authors: Z Y Zhang, S Matsumoto, T Kiyoshi, Ryo TeranishiAbstract:High field concentration and magnetothermal stability are critical considerations when designing and fabricating Magnetic Lenses made from a stack of bulk high-temperature superconducting (HTS) material. In a previous study, we investigated a GdBCO Magnetic lens for use as a compact high-field superconducting magnet, but it cracked due to a high flux jump. In the present study, we investigate the Magnetic performance of an improved GdBCO lens. This new lens had almost the same dimensions as the previous one, but it was impregnated with epoxy resin to prevent it breaking. The impregnated lens exhibited superior stability and Magnetic properties, making it promising for use in a compact magnet system. A maximum field of 13 T was obtained at 20 K with no flux jump.
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Magnetic field, temperature and mechanical crack performance of a GdBCO Magnetic lens
Superconductor Science and Technology, 2012Co-Authors: Z Y Zhang, Ryo Teranishi, Shinji Matsumoto, T KiyoshiAbstract:Magnetic field concentration by using the diamagnetism of a superconductor is a novel technique that has been experimentally demonstrated in Magnetic Lenses. A Magnetic lens consists of a hollow superconductor cylinder with a tapered inner diameter within which the Magnetic flux is concentrated by diamagnetism. Magnetic Lenses are very promising for use in compact high Magnetic field systems. However, Magnetic Lenses with large inner diameters are required to facilitate sample access during use. In this study, an optimized GdBaCuO Magnetic lens with large inner and outer diameters was designed and its performance was investigated in liquid nitrogen, liquid helium, and a cryocooler-cooled cryostat. A lens with an inner diameter of 12 mm was constructed by stacking three specially machined GdBaCuO bulk pieces. This Magnetic lens cracked due to the large flux jump that occurred when the concentrated field of the Magnetic lens exceeded 10 T at 4.2 K. The cracked lens was subsequently impregnated with epoxy resin. A concentrated field of 12.42 T was realized when the background field was 8 T at 20 K and no flux jumps occurred. This result demonstrates that this GdBCO Magnetic lens is promising for use in compact superconducting magnet systems.
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Magnetic Lenses using different mgb 2 bulk superconductors
Superconductor Science and Technology, 2012Co-Authors: Z Y Zhang, S Choi, S Matsumoto, R Teranishi, G Giunchi, Figini A Albisetti, T KiyoshiAbstract:A Magnetic lens allows the concentration of Magnetic fields using the diamagnetism of superconductors. The important features of the Magnetic lens are a tapered inner diameter from which the Magnetic flux is extruded and a slit to suppress the circumference current that shields the Magnetic flux. This concept was experimentally confirmed through the use of GdBaCuO bulks and a stack of NbTi/Nb/Cu sheets. We refer to this arrangement as a Magnetic lens.The Mg-reactive liquid infiltration (Mg-RLI) process developed by Edison SpA is suitable for the production of large and high-density MgB2 bulks. Three MgB2 bulk Magnetic Lenses, each with a different microstructure, were fabricated following the Mg-RLI process. The properties of the MgB2 Magnetic Lenses were measured in a cryocooler system as well as in liquid helium. The results confirmed that the MgB2 bulk Magnetic Lenses could concentrate a Magnetic field and that their field concentration properties were greatly affected by the temperature and the external field. In addition, the microstructure of the MgB2 bulk also had an influence on the Magnetic properties at different external fields. The results indicated that the MgB2 lens might be utilized as a field amplifier in intermediate fields.
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comparison of different configurations of nbti Magnetic Lenses
Superconductor Science and Technology, 2011Co-Authors: Z Y Zhang, S Choi, S Matsumoto, T Kiyoshi, Ryo TeranishiAbstract:Magnetic Lenses are new devices that concentrate Magnetic flux by using the diamagnetism of superconductors. Magnetic Lenses of two types made from NbTi sheets were constructed; measurements were made on them and they were systematically studied. Type A was constructed by stacking NbTi rings that had identical outer diameters and increasing inner diameters to form a hollow cone. Each ring had a slit to suppress the circumference current. Three construction methods for type A were tested: the rings were stacked with their slits aligned but with no insulation between the rings (A-1), with their slits aligned and with insulation between the rings (A-2), and with their slits in different positions and with insulation between the rings (A-3). For type B, sheets were rolled into hollow cones. Three identical cones were stacked to form a lens (B-1) and a single cone was used as a reference lens (B-2). The Lenses were assembled in a cryocooler-cooled cryostat with a NbTi magnet. The quenching behavior, concentration ratio, hysteresis, and decay behavior were measured. Because of its larger dimensions, type B had a larger concentration ratio (2.49 for B-1) than type A (1.87 for A-1). Both Lenses (types A and B-1) were quenched when the concentrated flux density reached about 0.64 T. The results suggest that quenching was caused by the NbTi sheet itself.
Nils Spengler - One of the best experts on this subject based on the ideXlab platform.
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Magnetic lenz Lenses improve the limit of detection in nuclear Magnetic resonance
PLOS ONE, 2017Co-Authors: Jan G Korvink, Nils Spengler, Peter T While, Markus Meissner, Ulrike WallrabeAbstract:A high NMR detection sensitivity is indispensable when dealing with mass and volume-limited samples, or whenever a high spatial resolution is required. The use of miniaturised RF coils is a proven way to increase sensitivity, but situations may arise where space restrictions could prevent the use of a small resonant coil, e.g., in the interior of the smallest practicable micro-coils. We present the use of Magnetic Lenses, denoted as Lenz Lenses due to their working principle, to focus the Magnetic flux of an RF coil into a smaller volume and thereby locally enhance the sensitivity of the NMR experiment—at the expense of the total sensitive volume. Besides focusing, such Lenses facilitate re-guiding or re-shaping of Magnetic fields much like optical Lenses do with light beams. For the first time we experimentally demonstrate the use of Lenz Lenses in Magnetic resonance and provide a compact mathematical description of the working principle. Through simulations we show that optimal arrangements can be found.