Pub Date : 2019-07-01DOI: 10.1109/ISEC46533.2019.8990944
Saburo Tanaka, M. Hayashi, T. Ohtani
We developed a metallic contaminant detector using a high-Tc (HTS) rf-SQUID for a lithium-ion battery slurry. For manufacturers producing industrial products, problems arising from metallic contaminants are critical issues requiring effective solutions. A detection system using a SQUID is a powerful tool for sensitive inspections on production lines. In this study, the slurry of a lithium-ion battery is the target of the inspection. Since slurry flows in a tube at the production lines, the SQUID sensor should be installed as close to the slurry as possible to obtain higher sensitivity. Therefore, we designed a micro scope type SQUID cryostat, in which the SQUID can approach the target as close as 1mm. We supposed the inner dimension of the slurry tube as 50 mm in diameter. The sample, a steel ball with diameter of 300 micrometers, was stuck on a thin fishing line and drawn by a motor in the tube. The signals scaled inversely well with the cube of the stand-off distance; it was found that the signal with a distance of 44 mm could be detected by extrapolating the slope line if the signal- to- noise ratio SNR > 3 was supposed as a threshold. The dependence on the sample diameter was also evaluated. After the systematic evaluation, the results suggested that a steel ball with a diameter of $33 mu mathrm{m}$ can be detected.
我们开发了一种用于锂离子电池浆料的高tc (HTS) rf-SQUID金属污染物探测器。对于生产工业产品的制造商来说，金属污染物产生的问题是需要有效解决的关键问题。使用SQUID的检测系统是对生产线进行敏感检测的强大工具。在本研究中，锂离子电池的浆液是检测的目标。由于浆液在生产线上的管道中流动，SQUID传感器应尽可能靠近浆液安装，以获得更高的灵敏度。因此，我们设计了一种显微镜型SQUID低温恒温器，其中SQUID可以接近目标1mm。我们假定浆管的内径为直径50mm。样品是一个直径为300微米的钢球，被粘在一根细鱼线上，由管子里的马达牵引。信号与隔离距离的立方成反比;结果表明，以信噪比SNR > 3为阈值，外推斜率线可以检测到距离为44 mm的信号。对样品直径的依赖性也进行了评价。经过系统评价，结果表明，可以检测到直径为$33 mu mathm {m}$的钢球。
{"title":"Development of Metallic Contaminant Detection System Using High-Tc RF SQUIDs for Li-ion Battery Slurry","authors":"Saburo Tanaka, M. Hayashi, T. Ohtani","doi":"10.1109/ISEC46533.2019.8990944","DOIUrl":"https://doi.org/10.1109/ISEC46533.2019.8990944","url":null,"abstract":"We developed a metallic contaminant detector using a high-Tc (HTS) rf-SQUID for a lithium-ion battery slurry. For manufacturers producing industrial products, problems arising from metallic contaminants are critical issues requiring effective solutions. A detection system using a SQUID is a powerful tool for sensitive inspections on production lines. In this study, the slurry of a lithium-ion battery is the target of the inspection. Since slurry flows in a tube at the production lines, the SQUID sensor should be installed as close to the slurry as possible to obtain higher sensitivity. Therefore, we designed a micro scope type SQUID cryostat, in which the SQUID can approach the target as close as 1mm. We supposed the inner dimension of the slurry tube as 50 mm in diameter. The sample, a steel ball with diameter of 300 micrometers, was stuck on a thin fishing line and drawn by a motor in the tube. The signals scaled inversely well with the cube of the stand-off distance; it was found that the signal with a distance of 44 mm could be detected by extrapolating the slope line if the signal- to- noise ratio SNR > 3 was supposed as a threshold. The dependence on the sample diameter was also evaluated. After the systematic evaluation, the results suggested that a steel ball with a diameter of $33 mu mathrm{m}$ can be detected.","PeriodicalId":250606,"journal":{"name":"2019 IEEE International Superconductive Electronics Conference (ISEC)","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128619954","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-01DOI: 10.1109/ISEC46533.2019.8990917
O. Kieler, L. Palafox, J. Ireland, J. Williams, B. Karlsen, H. Malmbekk, H. Tian, R. Gerdau, R. Wendisch, J. Kohlmann, P. Ohlckers, E. Bardalen, M. Akram, R. Behr
The pulse-driven Josephson Voltage Standard, also called Josephson Arbitrary Waveform Synthesizer (JAWS) is already well established for different applications in AC voltage metrology. To further increase the output voltage towards 10 V and to reduce the complexity of the JAWS systems we investigated two different approaches, which finally can be combined. One approach is to integrate an optimized on-chip power splitter to reduce the number of high-frequency (HF) channels from room temperature down to 4 K. A pulse pattern generator with less HF outputs will directly reduce the complexity and costs of a JAWS system. The second approach is to use an optical pulse-drive implementing cold photodiodes close to the JAWS chip. The use of optical fiber will have two main advantages: the optical fibers will reduce the high frequency noise and will enable an easy splitting into parallel optical channels. We will present first results with both approaches.
{"title":"Optical pulse-drive and on-chip power splitter for the pulse-driven AC Josephson Voltage Standard","authors":"O. Kieler, L. Palafox, J. Ireland, J. Williams, B. Karlsen, H. Malmbekk, H. Tian, R. Gerdau, R. Wendisch, J. Kohlmann, P. Ohlckers, E. Bardalen, M. Akram, R. Behr","doi":"10.1109/ISEC46533.2019.8990917","DOIUrl":"https://doi.org/10.1109/ISEC46533.2019.8990917","url":null,"abstract":"The pulse-driven Josephson Voltage Standard, also called Josephson Arbitrary Waveform Synthesizer (JAWS) is already well established for different applications in AC voltage metrology. To further increase the output voltage towards 10 V and to reduce the complexity of the JAWS systems we investigated two different approaches, which finally can be combined. One approach is to integrate an optimized on-chip power splitter to reduce the number of high-frequency (HF) channels from room temperature down to 4 K. A pulse pattern generator with less HF outputs will directly reduce the complexity and costs of a JAWS system. The second approach is to use an optical pulse-drive implementing cold photodiodes close to the JAWS chip. The use of optical fiber will have two main advantages: the optical fibers will reduce the high frequency noise and will enable an easy splitting into parallel optical channels. We will present first results with both approaches.","PeriodicalId":250606,"journal":{"name":"2019 IEEE International Superconductive Electronics Conference (ISEC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128721357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-01DOI: 10.1109/ISEC46533.2019.8990915
W. Xuan, Guangming Tang, Pei-Yao Qu, Zhi Tang, Xiao-Chun Ye, D. Fan, Zhimin Zhang, Ning-Hui Sun
Logic design of a 16-bit bit-slice shifter for 64-bit superconducting rapid single-flux-quantum (RSFQ) microprocessors is proposed. The shifter supports three types of shift operations including logic shift, arithmetic shift and rotating shift. Each of 64-bit shift input operands is divided into four slices of 16-bit each. In order to simulate the digital function and timing of the proposed 16-bit bit-slice shifter, we design a logic-level simulation model based on the Open Dataset of CONNECT Cell Library for AIST ADP2. As the results of simulation, the information of RSFQ circuits, such as the number of Josephson junctions, area and latency of the 16-bit bit slice shifter can be obtained. The simulation results show that the proposed 16-bit bit-slice shifter can work correctly.
{"title":"Logic Design of a 16-bit Bit-Slice Shifter for 64-bit RSFQ Microprocessors","authors":"W. Xuan, Guangming Tang, Pei-Yao Qu, Zhi Tang, Xiao-Chun Ye, D. Fan, Zhimin Zhang, Ning-Hui Sun","doi":"10.1109/ISEC46533.2019.8990915","DOIUrl":"https://doi.org/10.1109/ISEC46533.2019.8990915","url":null,"abstract":"Logic design of a 16-bit bit-slice shifter for 64-bit superconducting rapid single-flux-quantum (RSFQ) microprocessors is proposed. The shifter supports three types of shift operations including logic shift, arithmetic shift and rotating shift. Each of 64-bit shift input operands is divided into four slices of 16-bit each. In order to simulate the digital function and timing of the proposed 16-bit bit-slice shifter, we design a logic-level simulation model based on the Open Dataset of CONNECT Cell Library for AIST ADP2. As the results of simulation, the information of RSFQ circuits, such as the number of Josephson junctions, area and latency of the 16-bit bit slice shifter can be obtained. The simulation results show that the proposed 16-bit bit-slice shifter can work correctly.","PeriodicalId":250606,"journal":{"name":"2019 IEEE International Superconductive Electronics Conference (ISEC)","volume":"76 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126212914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-01DOI: 10.1109/ISEC46533.2019.8990928
B. Hampel, M. Tollkühn, I. Elenskiy, M. Schilling
Metamaterials are subwavelength structures that can be employed to modify properties of electromagnetic radiation. Their possible fields of application are very diverse and range from antennas to optical filter structures [1]. In this work, a THz microscope setup is employed to characterize additive manufactured metamaterial structures. These structures are optimized for a frequency of f = 24.05 GHz and are additive manufactured by the stereolithographic 3D printer Formlabs Form 2. A low-cost radar chip is used as a source of radiation with a frequency of f= 24.05 GHz and a power of up to 20 dBm. The manufactured structures are positioned between the source and the Josephson cantilever. Measurement results are presented for different metamaterial structures and are visualized in three dimensions. The presented method can be employed for rapid prototyping of metamaterial structures for microwave and terahertz radiation, which are subsequently characterized by THz microscopy.
超材料是一种亚波长结构，可以用来改变电磁辐射的特性。它们可能的应用领域非常广泛，从天线到光学滤波器结构[1]。在这项工作中，采用太赫兹显微镜装置来表征增材制造的超材料结构。这些结构的优化频率为f = 24.05 GHz，由立体光刻3D打印机Formlabs Form 2进行增材制造。采用低成本雷达芯片作为辐射源，频率为f= 24.05 GHz，功率高达20 dBm。制造的结构位于源和约瑟夫森悬臂之间。对不同的超材料结构给出了测量结果，并以三维形式显示。该方法可用于微波和太赫兹辐射下的超材料结构的快速成型，然后用太赫兹显微镜对其进行表征。
{"title":"THz Microscopy of Additive Manufactured Metamaterials at 24 GHz with Josephson Cantilevers","authors":"B. Hampel, M. Tollkühn, I. Elenskiy, M. Schilling","doi":"10.1109/ISEC46533.2019.8990928","DOIUrl":"https://doi.org/10.1109/ISEC46533.2019.8990928","url":null,"abstract":"Metamaterials are subwavelength structures that can be employed to modify properties of electromagnetic radiation. Their possible fields of application are very diverse and range from antennas to optical filter structures [1]. In this work, a THz microscope setup is employed to characterize additive manufactured metamaterial structures. These structures are optimized for a frequency of f = 24.05 GHz and are additive manufactured by the stereolithographic 3D printer Formlabs Form 2. A low-cost radar chip is used as a source of radiation with a frequency of f= 24.05 GHz and a power of up to 20 dBm. The manufactured structures are positioned between the source and the Josephson cantilever. Measurement results are presented for different metamaterial structures and are visualized in three dimensions. The presented method can be employed for rapid prototyping of metamaterial structures for microwave and terahertz radiation, which are subsequently characterized by THz microscopy.","PeriodicalId":250606,"journal":{"name":"2019 IEEE International Superconductive Electronics Conference (ISEC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124297750","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-01DOI: 10.1109/ISEC46533.2019.8990896
Yu Zhou, Zhihui Peng, Yuta Horiuchi, O. Astafiev, J. Tsai
Single-photon sources of high efficiency are of great interest because they are the key elements in many prospective quantum technologies and applications. Based on our previous work, here we demonstrate a high-quality tunable microwave single-photon source based on transmon qubit with intrinsic emission efficiency more than 99%. To further confirm the single-photon property of the source, we study the single-photon interference in a Hanbury-Brown-Twiss (HBT) type setup and measure the correlation functions of the emission field using linear detectors with GPU-enhanced signal processing technique. The antibunching in second-order correlation function is clearly observed. The theoretical calculations agree well with the experimental results. Such a high-quality single-photon source may be used as a building block for quantum communication, simulation and information processing in microwave regime.
{"title":"Efficient Tunable Microwave Single-photon Source Based on Transmon Qubit","authors":"Yu Zhou, Zhihui Peng, Yuta Horiuchi, O. Astafiev, J. Tsai","doi":"10.1109/ISEC46533.2019.8990896","DOIUrl":"https://doi.org/10.1109/ISEC46533.2019.8990896","url":null,"abstract":"Single-photon sources of high efficiency are of great interest because they are the key elements in many prospective quantum technologies and applications. Based on our previous work, here we demonstrate a high-quality tunable microwave single-photon source based on transmon qubit with intrinsic emission efficiency more than 99%. To further confirm the single-photon property of the source, we study the single-photon interference in a Hanbury-Brown-Twiss (HBT) type setup and measure the correlation functions of the emission field using linear detectors with GPU-enhanced signal processing technique. The antibunching in second-order correlation function is clearly observed. The theoretical calculations agree well with the experimental results. Such a high-quality single-photon source may be used as a building block for quantum communication, simulation and information processing in microwave regime.","PeriodicalId":250606,"journal":{"name":"2019 IEEE International Superconductive Electronics Conference (ISEC)","volume":"112 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122067328","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-01DOI: 10.1109/ISEC46533.2019.8990940
M. Tollkühn, I. Elenskiy, B. Hampel, M. Schilling
Josephson cantilevers, based on high temperature superconducting Josephson junctions, are versatile detectors for the measurement of frequency and power of microwave and terahertz radiation. A Josephson cantilever consists of at least one Josephson junction, which is equipped with an antenna structure for better coupling. The Josephson junctions, made from the high-temperature superconductor YBa2Cu3O7, are deployed on LaAIO3or MgO bicrystal substrates. Four feedlines are used to carry out four-terminal sensing. The THz microscope was developed, to allow three dimensional measurements [1]. In this measurement setup, the Josephson cantilever is mounted on a 15 × 15 × 15 mm3positioning system inside a vacuum chamber. The Josephson cantilever is cooled by a cryocooler that allows operating temperatures down to 30 K. A triangular current is injected into the junction and the current-voltage characteristic is recorded at each spatial point. The frequency and the power of the external radiation can be determined from the recorded data by evaluating the occurring Shapiro steps using Hilbert spectroscopy [2]. When the Josephson cantilever is irradiated with more than one frequency at a time, it behaves as a frequency mixer, due to its nonlinear current-voltage characteristic. In this work, we investigated the mixing of 40 GHz and 762 GHz signals with the THz microscope.
{"title":"Characterization of 40 GHz and 762 GHz sources with superconducting Josephson cantilevers in a THz microscope","authors":"M. Tollkühn, I. Elenskiy, B. Hampel, M. Schilling","doi":"10.1109/ISEC46533.2019.8990940","DOIUrl":"https://doi.org/10.1109/ISEC46533.2019.8990940","url":null,"abstract":"Josephson cantilevers, based on high temperature superconducting Josephson junctions, are versatile detectors for the measurement of frequency and power of microwave and terahertz radiation. A Josephson cantilever consists of at least one Josephson junction, which is equipped with an antenna structure for better coupling. The Josephson junctions, made from the high-temperature superconductor YBa2Cu3O7, are deployed on LaAIO3or MgO bicrystal substrates. Four feedlines are used to carry out four-terminal sensing. The THz microscope was developed, to allow three dimensional measurements [1]. In this measurement setup, the Josephson cantilever is mounted on a 15 × 15 × 15 mm3positioning system inside a vacuum chamber. The Josephson cantilever is cooled by a cryocooler that allows operating temperatures down to 30 K. A triangular current is injected into the junction and the current-voltage characteristic is recorded at each spatial point. The frequency and the power of the external radiation can be determined from the recorded data by evaluating the occurring Shapiro steps using Hilbert spectroscopy [2]. When the Josephson cantilever is irradiated with more than one frequency at a time, it behaves as a frequency mixer, due to its nonlinear current-voltage characteristic. In this work, we investigated the mixing of 40 GHz and 762 GHz signals with the THz microscope.","PeriodicalId":250606,"journal":{"name":"2019 IEEE International Superconductive Electronics Conference (ISEC)","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116817788","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-01DOI: 10.1109/ISEC46533.2019.8990945
S. Shahsavani, R. Tadros, P. Beerel, M. Pedram
Single Flux Quantum (SFQ) is a promising option for high performance and low power supercomputing platforms. Nevertheless, timing uncertainty represents an obstacle to the design of high-frequency clock distribution networks. The hierarchical chains of homogeneous clover-leaves clocking, $(mathrm{HC})^{2}mathrm{LC}$. was proposed as an innovative solution to this challenge. This paper presents a novel algorithm for the physical implementation of $(mathrm{HC})^{2}mathrm{LC}$ networks. The proposed method models the (HC)2LC network as a directed graph with multiple cycles representing the synchronizing feedback signals. This graph is then transformed to a directed acyclic graph (DAG) by eliminating feedback edges. The physical location of the nodes in the generated DAG (such as splitters and C-junctions) in the Manhattan plane is calculated using a zero-skew clock embedding algorithm. Additionally, a novel mixed integer linear programming (MILP) based approach minimizes the maximum clock skew among the sinks of the clock network and the sum of the delay of the edges in feedback loops, simultaneously. Experimental results show that using the proposed approach, the average clock skew for five benchmark circuits is 4.6ps.
{"title":"A Clock Synthesis Algorithm for Hierarchical Chains of Homogeneous Clover-Leaves Clock Networks for Single Flux Quantum Logic Circuits","authors":"S. Shahsavani, R. Tadros, P. Beerel, M. Pedram","doi":"10.1109/ISEC46533.2019.8990945","DOIUrl":"https://doi.org/10.1109/ISEC46533.2019.8990945","url":null,"abstract":"Single Flux Quantum (SFQ) is a promising option for high performance and low power supercomputing platforms. Nevertheless, timing uncertainty represents an obstacle to the design of high-frequency clock distribution networks. The hierarchical chains of homogeneous clover-leaves clocking, $(mathrm{HC})^{2}mathrm{LC}$. was proposed as an innovative solution to this challenge. This paper presents a novel algorithm for the physical implementation of $(mathrm{HC})^{2}mathrm{LC}$ networks. The proposed method models the (HC)2LC network as a directed graph with multiple cycles representing the synchronizing feedback signals. This graph is then transformed to a directed acyclic graph (DAG) by eliminating feedback edges. The physical location of the nodes in the generated DAG (such as splitters and C-junctions) in the Manhattan plane is calculated using a zero-skew clock embedding algorithm. Additionally, a novel mixed integer linear programming (MILP) based approach minimizes the maximum clock skew among the sinks of the clock network and the sum of the delay of the edges in feedback loops, simultaneously. Experimental results show that using the proposed approach, the average clock skew for five benchmark circuits is 4.6ps.","PeriodicalId":250606,"journal":{"name":"2019 IEEE International Superconductive Electronics Conference (ISEC)","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126413233","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-01DOI: 10.1109/ISEC46533.2019.8990960
Y. Yamanashi, Akiyoshi Sanada, N. Yoshikawa
We have been developing the floating-point unit (FPU) based on single-flux-quantum (SFQ) logic toward a highspeed and low-power superconducting graphical processing unit. The floating-point divider is the most complicated circuit element of the SFQ FPU. We designed the SFQ floating-point divider on the basis of Goldschmidt's algorithm, which is one of multiplicative hardware algorithms for division. Because the multiplies in the divider can be used for multiplication in the FPU by employing the multiplicative division algorithm, the FPU can be efficiently designed by using the designed floating-point divider. We show the circuit scale estimation of the FPU that uses the designed divider as a function on floating-point precision. We measured the 4-bit and 11-bit SFQ floating-point dividers implemented by the AIST 10 kA/cm2 Nb advanced process. The 11-bit SFQ floating- point divider is composed of 8091 Josephson junctions and can be applied to half-precision FPU. We confirmed correct operation of the 4-bit SFQ divider by low-frequency function test.
{"title":"Measurement of Single-Flux-Quantum Floating-Point Divider Based on Goldschmidt's Algorithm","authors":"Y. Yamanashi, Akiyoshi Sanada, N. Yoshikawa","doi":"10.1109/ISEC46533.2019.8990960","DOIUrl":"https://doi.org/10.1109/ISEC46533.2019.8990960","url":null,"abstract":"We have been developing the floating-point unit (FPU) based on single-flux-quantum (SFQ) logic toward a highspeed and low-power superconducting graphical processing unit. The floating-point divider is the most complicated circuit element of the SFQ FPU. We designed the SFQ floating-point divider on the basis of Goldschmidt's algorithm, which is one of multiplicative hardware algorithms for division. Because the multiplies in the divider can be used for multiplication in the FPU by employing the multiplicative division algorithm, the FPU can be efficiently designed by using the designed floating-point divider. We show the circuit scale estimation of the FPU that uses the designed divider as a function on floating-point precision. We measured the 4-bit and 11-bit SFQ floating-point dividers implemented by the AIST 10 kA/cm2 Nb advanced process. The 11-bit SFQ floating- point divider is composed of 8091 Josephson junctions and can be applied to half-precision FPU. We confirmed correct operation of the 4-bit SFQ divider by low-frequency function test.","PeriodicalId":250606,"journal":{"name":"2019 IEEE International Superconductive Electronics Conference (ISEC)","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126559994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-01DOI: 10.1109/ISEC46533.2019.8990912
R. Körber, O. Kieler, P. Hömmen, N. Höfner, J. Storm
We present the use of our ultra-sensitive SQUID system in the field of biomagnetism and ultra-low field (ULF) MRI. A current sensor configuration is used where a pickup coil is inductively coupled to the SQUID. A 1st-order axial gradiometer system, operated in a liquid He dewar with negligible noise, achieves a measured coupled energy sensitivity $epsilon_{c}$ of 40 $h$ and a white noise below 200 aT $mathrm{Hz}^{-1/2}$. As an example of its use in biomagnetism, we discuss single trial magnetoencephalography measurements of high frequency bursts at 600 Hz from the somatosensory cortex which are related to synchronized spiking activity of individual neurons. We also deploy this system for ultra-low field MRI where it is operated inside an MRI coil system with several fast-switchable field and gradient coils. This necessitates the use of a current limiter in the input circuit and a 2nd-order axial gradiometer leading to an increased noise of 380 aT $mathrm{Hz}^{-1/2}$. Here, we demonstrated full tensor current density imaging of impressed currents in phantoms. For further improvement of the noise, the fabrication process for the nanometer-sized Josephson junctions based on the HfTi self-shunted junction technology has been extended to a SIS process with AlOx as the insulating layer. We achieved noise levels of 330 $mathrm{n}Phi_{0}mathrm{Hz}^{-1/2}$ and 550 $mathrm{n}Phi_{0}mathrm{Hz}^{-1/2}$, corresponding to energy sensitivities of 5 $h$ and 20 $h$ for uncoupled and coupled SQUIDs, respectively.
我们介绍了我们的超灵敏SQUID系统在生物磁性和超低场(ULF) MRI领域的应用。电流传感器配置中，拾取线圈电感耦合到SQUID。一阶轴向梯度仪系统在噪声可忽略的液体He杜瓦瓶中工作，测量到的耦合能量灵敏度$epsilon_{c}$为40 $h$，白噪声低于200 aT $mathrm{Hz}^{-1/2}$。作为其在生物磁学中使用的一个例子，我们讨论了来自体感觉皮层的600 Hz高频脉冲的单次试验脑磁图测量，这与单个神经元的同步峰活动有关。我们还将该系统应用于超低场MRI，该系统在MRI线圈系统中运行，该系统具有几个快速切换的场和梯度线圈。这需要在输入电路中使用限流器和二阶轴向梯度仪，导致噪声增加380 aT $mathrm{Hz}^{-1/2}$。在这里，我们展示了在幻影中外加电流的全张量电流密度成像。为了进一步改善噪声，基于HfTi自分流结技术的纳米Josephson结的制造工艺已扩展到以AlOx为绝缘层的SIS工艺。我们获得了330 $mathrm{n}Phi_{0}mathrm{Hz}^{-1/2}$和550 $mathrm{n}Phi_{0}mathrm{Hz}^{-1/2}$的噪声水平，对应于未耦合和耦合squid的能量灵敏度分别为5 $h$和20 $h$。
{"title":"Ultra-sensitive SQUID systems for applications in biomagnetism and ultra-low field MRI","authors":"R. Körber, O. Kieler, P. Hömmen, N. Höfner, J. Storm","doi":"10.1109/ISEC46533.2019.8990912","DOIUrl":"https://doi.org/10.1109/ISEC46533.2019.8990912","url":null,"abstract":"We present the use of our ultra-sensitive SQUID system in the field of biomagnetism and ultra-low field (ULF) MRI. A current sensor configuration is used where a pickup coil is inductively coupled to the SQUID. A 1st-order axial gradiometer system, operated in a liquid He dewar with negligible noise, achieves a measured coupled energy sensitivity $epsilon_{c}$ of 40 $h$ and a white noise below 200 aT $mathrm{Hz}^{-1/2}$. As an example of its use in biomagnetism, we discuss single trial magnetoencephalography measurements of high frequency bursts at 600 Hz from the somatosensory cortex which are related to synchronized spiking activity of individual neurons. We also deploy this system for ultra-low field MRI where it is operated inside an MRI coil system with several fast-switchable field and gradient coils. This necessitates the use of a current limiter in the input circuit and a 2nd-order axial gradiometer leading to an increased noise of 380 aT $mathrm{Hz}^{-1/2}$. Here, we demonstrated full tensor current density imaging of impressed currents in phantoms. For further improvement of the noise, the fabrication process for the nanometer-sized Josephson junctions based on the HfTi self-shunted junction technology has been extended to a SIS process with AlOx as the insulating layer. We achieved noise levels of 330 $mathrm{n}Phi_{0}mathrm{Hz}^{-1/2}$ and 550 $mathrm{n}Phi_{0}mathrm{Hz}^{-1/2}$, corresponding to energy sensitivities of 5 $h$ and 20 $h$ for uncoupled and coupled SQUIDs, respectively.","PeriodicalId":250606,"journal":{"name":"2019 IEEE International Superconductive Electronics Conference (ISEC)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123692466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-01DOI: 10.1109/ISEC46533.2019.8990916
Stephen J. McCoy, E. Cho, Hao Li, S. Cybart
HoBa2Cu3O7-δ (HBCO) thin films were grown by reactive sputtering on SrTiO3 (STO), (LaAlO3)0.3(Sr2 TaAlO6)0.7 (LSAT), and NdGaO3 (NGO) substrates for optimization of electrical properties for superconductive electronics. By changing deposition temperature and oxygen partial pressures we were able to obtain films with critical temperatures of 92 K and critical current density of 3 MA/cm2. HBCO Josephson junctions were fabricated using focused helium ion beam irradiation that exhibited excellent properties.
{"title":"Ho-Ba-Cu-O Thin Films for Superconductive Electronics","authors":"Stephen J. McCoy, E. Cho, Hao Li, S. Cybart","doi":"10.1109/ISEC46533.2019.8990916","DOIUrl":"https://doi.org/10.1109/ISEC46533.2019.8990916","url":null,"abstract":"HoBa<inf>2</inf>Cu<inf>3</inf>O<inf>7-δ</inf> (HBCO) thin films were grown by reactive sputtering on SrTiO<inf>3</inf> (STO), (LaAlO<inf>3</inf>)<inf>0.3</inf>(Sr<inf>2</inf> TaAlO<inf>6</inf>)<inf>0.7</inf> (LSAT), and NdGaO<inf>3</inf> (NGO) substrates for optimization of electrical properties for superconductive electronics. By changing deposition temperature and oxygen partial pressures we were able to obtain films with critical temperatures of 92 K and critical current density of 3 MA/cm<sup>2</sup>. HBCO Josephson junctions were fabricated using focused helium ion beam irradiation that exhibited excellent properties.","PeriodicalId":250606,"journal":{"name":"2019 IEEE International Superconductive Electronics Conference (ISEC)","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125197562","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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