Superconductivity最新文献

{"title":"32 × 32 NbN SNSPD array based on thermally coupled row-column multiplexing architecture","authors":"TianZhu Zhang ,&nbsp;You Xiao ,&nbsp;HuiQin Yu ,&nbsp;Jia Huang ,&nbsp;ChaoLin Lv ,&nbsp;LingDong Kong ,&nbsp;XiaoYu Liu ,&nbsp;Hao Li ,&nbsp;LiXing You ,&nbsp;Zhen Wang","doi":"10.1016/j.supcon.2023.100056","DOIUrl":"https://doi.org/10.1016/j.supcon.2023.100056","url":null,"abstract":"<div><p>We report a superconducting nanowire single-photon detector (SNSPD) array aiming for a near-infrared 1550-nm wavelength that consists of 32 × 32 nanowire pixels and an area of 0.96 mm × 0.96 mm. Unlike most reported large-scale SNSPD arrays with amorphous films, NbN superconducting nanowires are employed in our array, which allows the detector operation at 2.3 K provided by a compact two-stage Gifford–McMahon cryocooler. Thermally coupled row–column multiplexing is employed in our arrays to avoid current redistribution and loss of electrical signal occurring in the electrically coupled row–column architecture. The fabricated detector array shows a pixel yield of 94% and maximal intrinsic efficiencies of 77% and 96% at 1550 nm and 405 nm, respectively. The timing jitter and the thermal coupling probability are also investigated.</p></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"7 ","pages":"Article 100056"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49699019","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}

{"title":"Bending performance analysis on YBCO cable with high flexibility","authors":"Huan Jin ,&nbsp;Qiong Wu ,&nbsp;Guanyu Xiao ,&nbsp;Chao Zhou ,&nbsp;Haihong Liu ,&nbsp;Yunfei Tan ,&nbsp;Fang Liu ,&nbsp;Jinggang Qin","doi":"10.1016/j.supcon.2023.100054","DOIUrl":"https://doi.org/10.1016/j.supcon.2023.100054","url":null,"abstract":"<div><p>In order to utilize high-temperature superconducting Yttrium Barium Copper Oxide (YBCO) tapes to develop superconducting cables for high magnet field applications, it is critical to ensure the stable operation of the YBCO cable under challenging mechanical and thermal conditions. A new type of cable featuring the winding of YBCO and copper tapes around a spiral stainless steel tube has been proposed to increase flexibility and cooling. Experiments are performed to confirm that its critical current varies with the bending diameter. The cables wound with nine YBCO tapes in three layers show a critical current degradation of less than 5% for a bending diameter of 30 mm. The performance of the cable degrades as the number of wound layers increases. The critical current degradation of cable specimens wound from 15 tapes in five layers reached approximately 12% for a bending diameter of 30 mm. In addition, when compared to traditional CORC cable specimens, the developed cable specimens show better-bending flexibility and achieve a lower critical bending diameter. The finite element models show that the higher elasticity coefficient and lower plasticity of the stainless steel spiral tube results in a lower strain on the YBCO tapes of the HFRC cable than that of the CORC cable, and the maximum strain on the YBCO tapes of the HFRC cable was only about 10% of that of the CORC cable. Therefore, it is less likely that the YBCO tape in this type of cable will reach the irreversible strain limit during bending, resulting in a degradation in current carrying performance. Furthermore, the cooling efficiency can be improved by flowing the cooling medium inside the central core, which can significantly improve its thermal stability. These advantages indicate the possibility of using it in future high-field magnets with high current carrying capacity at fields greater than 15 T.</p></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"7 ","pages":"Article 100054"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49699005","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}

{"title":"Magnetic bearings with double crossed loops modelled with T-A formulation and electric circuits","authors":"Bárbara Maria Oliveira Santos ,&nbsp;Gabriel dos Santos ,&nbsp;Flávio Goulart dos Reis Martins ,&nbsp;Felipe Sass ,&nbsp;Guilherme Gonçalves Sotelo ,&nbsp;Rubens de Andrade Junior ,&nbsp;Francesco Grilli","doi":"10.1016/j.supcon.2023.100058","DOIUrl":"https://doi.org/10.1016/j.supcon.2023.100058","url":null,"abstract":"<div><p>The application of High-Temperature Superconductor (HTS) coils made of coated conductors has been investigated for many years. A possible configuration for such coils is the jointless loop, also known as the ring coil. The double crossed loop coil (DCLC) has been successfully applied in superconducting magnetic bearings (SMBs). The design of SMBs with DCLCs requires flexible modelling to allow all parts of the device to be represented. This work proposes the T-A formulation with a thin-film approximation for modelling SMB with DCLCs in the finite element analysis framework. A 2D representation of the system is coupled with an external electric circuit to model the continuity of the lines that represent the parts of each jointless loop. To couple the T-A formulation and the circuit, an average of the total electric field, with both resistive and inductive components, is applied to the circuit. The total current computed by the circuit is applied to the T-A formulation. The proposed methodology was validated by comparison with levitation force experimental data. Two types of tests were simulated: five levitation force tests and three guidance force tests. It is shown that there is a limit to the behaviour of the levitation force related to the high-loss state. Below this limit, the stack of DCLCs behaves as an equivalent bulk. Beyond this limit, a high-loss state appears as a linear growth of the levitation force. It is also shown that this high-loss state in vertical displacement influences the lateral force.</p></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"7 ","pages":"Article 100058"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49698731","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}

{"title":"Characterizations of the electrothermal parameters of a transition edge sensor microcalorimeter and its energy resolution","authors":"Yue Zhao,&nbsp;Hubing Wang,&nbsp;Bo Gao,&nbsp;Zhen Wang","doi":"10.1016/j.supcon.2023.100051","DOIUrl":"https://doi.org/10.1016/j.supcon.2023.100051","url":null,"abstract":"<div><p>We developed a transition-edge sensor microcalorimeter (μ-calorimeter) using Mo/Au/Au thin films. We report the detector fabrication, the measurements of the electrothermal parameters and the noise characterizations of the transition-edge sensor μ-calorimeters. We estimated the energy resolution of the μ-calorimeter using the measured noise spectrum and the calculated power-to-current responsivity. Using a ⁵⁵Fe radioactive X-ray source, we characterized the detector responses to incident photons at various working points. The best instrumental energy resolution achieved was 4.13 eV @ 5.9 keV, which agrees qualitatively with the resolution of 4.01 eV estimated from the noise spectrum.</p></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"7 ","pages":"Article 100051"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49698988","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}

{"title":"Estimation of critical current density of bulk superconductor with artificial neural network","authors":"Gangling Wu,&nbsp;Huadong Yong","doi":"10.1016/j.supcon.2023.100055","DOIUrl":"https://doi.org/10.1016/j.supcon.2023.100055","url":null,"abstract":"<div><p>In the applications of superconducting materials, the critical current density <span><math><mrow><msub><mi>J</mi><mi>c</mi></msub><mrow><mfenced><mrow><mi>B</mi></mrow></mfenced></mrow></mrow></math></span> is a crucial performance parameter. The conventional method of measuring <span><math><mrow><msub><mi>J</mi><mi>c</mi></msub><mrow><mfenced><mrow><mi>B</mi></mrow></mfenced></mrow></mrow></math></span> of bulk superconductor is magnetization method. However, there are errors in the estimation of <span><math><mrow><msub><mi>J</mi><mi>c</mi></msub><mrow><mfenced><mrow><mi>B</mi></mrow></mfenced></mrow></mrow></math></span> in the lower field, and the estimation is not applicable in the region where the magnetic field reverses. In this paper, <span><math><mrow><msub><mi>J</mi><mi>c</mi></msub><mrow><mfenced><mrow><mi>B</mi></mrow></mfenced></mrow></mrow></math></span> of the bulk superconductor is determined by the hysteresis and magnetostriction loops with artificial neural network (ANN), respectively. Compared with double-output ANN, the critical current density obtained by single-output ANN is more accurate. Finally, the prediction results given by the hysteresis and magnetostriction loops are discussed.</p></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"7 ","pages":"Article 100055"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49699009","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}

{"title":"The event and skepticism for the electrical conductor LK-99 at ambient temperature and pressure","authors":"Zili Zhang","doi":"10.1016/j.supcon.2023.100059","DOIUrl":"https://doi.org/10.1016/j.supcon.2023.100059","url":null,"abstract":"","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"7 ","pages":"Article 100059"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49698720","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}

{"title":"A full-wave HTS flux pump using a feedback control system","authors":"James H.P. Rice ,&nbsp;Ben P.P. Mallett ,&nbsp;Dominic A. Moseley ,&nbsp;Alexander Petrov ,&nbsp;Heng Zhang ,&nbsp;Steven Wray ,&nbsp;Rodney A. Badcock","doi":"10.1016/j.supcon.2023.100064","DOIUrl":"https://doi.org/10.1016/j.supcon.2023.100064","url":null,"abstract":"<div><p>Transformer-rectifier flux pumps are DC superconducting power supplies capable of charging superconducting magnets to high currents and stored magnetic energies. Here, we demonstrate a full-wave superconducting flux pump assembled from high-temperature superconducting (HTS) wire that utilizes superconducting switches controlled by applied magnetic field. A negative DC offset occurs in the superconducting secondary of the circuit during operation which is related to the output load current. A feedback control system is proposed and demonstrated to account for the negative DC offset. Increasing the primary current proportional to the load current during operation allowed for the maximum output of the flux pump to be increased from 35 A to more than 275 A. These results are reproduced using a coupled electrical- and magnetic–circuit model formulated in the MATLAB Simulink® package.</p></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"8 ","pages":"Article 100064"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49698993","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}

{"title":"Electrical, magnetic and thermal circuit modelling of a superconducting half-wave transformer rectifier flux pump using Simulink","authors":"A.C. Francis ,&nbsp;S. Venuturumilli ,&nbsp;D.A. Moseley ,&nbsp;S. Claridge ,&nbsp;B. Leuw ,&nbsp;R.A. Badcock ,&nbsp;C.W. Bumby","doi":"10.1016/j.supcon.2023.100053","DOIUrl":"https://doi.org/10.1016/j.supcon.2023.100053","url":null,"abstract":"<div><p>Superconducting flux pumps (FP) are capable of supplying superconducting circuits with high currents by additively supplying current over a number of cycles without introducing large amounts of heat into the cryogenic environment. Superconducting FPs can be broadly classified into two types: dynamo and transformer rectifier. Modelling the behaviour of these systems is an emerging field. In this work a model of a half wave magnetically switched transformer rectifier FP created in MATLAB/Simulink/Simscape is presented. Unlike existing models, the characteristics of all circuit elements are fully integrated allowing all superconducting elements to be accurately incorporated. The presented method uses pre-calculated look-up tables, populated with experimentally derived material qualities to simulate these superconducting elements. The thermal evolution of the switches, calculated simultaneously to the magnetic field switching interaction has also been included. This model is compared to the performance of a real world FP during the pumping of a load coil and is found to be accurate. Furthermore, the presented model illustrates how small amounts of heating at a magnetic switch can profoundly affect a FPs performance over many cycles.</p></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"7 ","pages":"Article 100053"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49698995","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}

{"title":"Charging process simulation of a coil by a self-regulating high-Tc superconducting flux pump","authors":"Pengbo Zhou ,&nbsp;Yanyu Zhou ,&nbsp;Mark Ainslie ,&nbsp;Asef Ghabeli ,&nbsp;Francesco Grilli ,&nbsp;Guangtong Ma","doi":"10.1016/j.supcon.2023.100061","DOIUrl":"https://doi.org/10.1016/j.supcon.2023.100061","url":null,"abstract":"<div><p>Self-regulating high-temperature superconducting (HTS) flux pumps enable direct current injection into a closed-loop superconducting coil without any electrical contact. In this work, the process of charging a coil by a self-regulating HTS flux pump is examined in detail by numerical modeling. The proposed model combines an <span><math><mrow><mi>H</mi></mrow></math></span>-formulation finite element method (FEM) model with an electrical circuit, enabling a comprehensive evaluation of the overall performance of self-regulating HTS flux pumps while accurately capturing local effects. The results indicate that the proposed model can capture all the critical features of a self-regulating HTS flux pump, including superconducting properties and the impact of the secondary resistance. When the numerical results are compared to the experimental data, the presented model is found to be acceptable both qualitatively and quantitatively. Based on this model, we have demonstrated how the addition of a milliohm range, normal-conducting secondary resistance in series with the charging loop can improve the charging process. In addition, its impact on the charging performance is revealed, including the maximum achievable current, charging speed, and the generated losses. The modeling approach employed in this study can be generalized to the optimization and design of various types of flux pumps, potentially expediting their practical application.</p></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"7 ","pages":"Article 100061"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49698793","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}

{"title":"Field and current driven versions of Brandt method for calculating transport ac loss of superconducting cylinder and strip","authors":"Xiao-Fen Li ,&nbsp;Shuo Li ,&nbsp;Du-Xing Chen","doi":"10.1016/j.supcon.2023.100052","DOIUrl":"https://doi.org/10.1016/j.supcon.2023.100052","url":null,"abstract":"<div><p>As an elegant and fast numerical tool for solving time-dependent electromagnetic field problems in hard superconductors, Brandt’s method has played an important role in understading the magnetic behavior of superconducting strips, discs, bars and cylinders in various aspect ratios. However, the application of this convenient method was mainly in magnetization processes. Traditionally, the solution of current transport problem needs to introduce a driving electric field <span><math><mrow><msub><mrow><mi>E</mi></mrow><mrow><mi>a</mi></mrow></msub></mrow></math></span>, which requires a low efficiency iterative process and <span><math><mrow><msub><mrow><mi>E</mi></mrow><mrow><mi>a</mi></mrow></msub></mrow></math></span> itself was not clearly explained. In this work, three integral algorithms based on the Brandt’s method are developed to deal with current transport problems, which directly adopt the applied current as a boundary condition. Namely the current (<em>I</em>)-driven version and two current-field-driven versions A and B. Moreover, the arbitrary applied magnetic field can also be included in the <em>I</em>-driven version. The derivation with all necessary formulas for the methods are given in this work. As an example, the new methods, as well as the traditional method are used for calculating transport ac loss <em>Q</em> of a superconducting cylinder or strip obeying a power-law relation of <span><math><mrow><mi>E</mi><mo>∝</mo><msup><mrow><mi>J</mi></mrow><mrow><mi>n</mi></mrow></msup></mrow></math></span> as a function of a given <span><math><mrow><mi>I</mi><mo>(</mo><mi>t</mi><mo>)</mo></mrow></math></span>. Derived from the Ampère law and the differential rather than the integral expression of the Faraday law, the current-driven version can be used for more accurate and much quicker computation. Being an intermediate quantity, <span><math><mrow><msub><mrow><mi>E</mi></mrow><mrow><mi>a</mi></mrow></msub><mo>(</mo><mi>t</mi><mo>)</mo></mrow></math></span> in the two current-field-driven versions is accurately calculated under the given <span><math><mrow><mi>I</mi><mo>(</mo><mi>t</mi><mo>)</mo></mrow></math></span>, but version B is much quicker than A. Problems relating to <span><math><mrow><msub><mrow><mi>E</mi></mrow><mrow><mi>a</mi></mrow></msub><mo>(</mo><mi>t</mi><mo>)</mo></mrow></math></span> and <em>Q</em> stabilization process are discussed.</p></div>","PeriodicalId":101185,"journal":{"name":"Superconductivity","volume":"7 ","pages":"Article 100052"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49698989","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}