In this article, we report the electrical (dark) characterization of lumped-element kinetic inductance detectors (LEKIDs) fabricated from a titanium/aluminum bilayer and designed for broadband absorption in the $W$-band (75–110 GHz). These detectors are prototypes for future quantum chromodynamics axion search experiments within the Canfranc axion detection experiment (CADEx), which demand sub-$10^{-19} text{W}/sqrt{text{Hz}}$ sensitivities under low optical backgrounds. We combine a Mattis–Bardeen analysis to the temperature dependence of the detector parameters with noise spectroscopy to determine the electrical noise equivalent power (NEP). The minimum measured value for the electrical NEP is $sim 3 times 10^{-19} text{W}/sqrt{text{Hz}}$. Across the measured temperature range, we find that quasiparticle lifetime deviates from the expected BCS recombination law. Our analysis suggests that nonequilibrium relaxation is governed by spatial inhomogeneities in the superconducting gap and phonon diffusion effects. This work sets the road-map to achieve suitable and ultra-sensitive detectors in the $W$-band for dark matter axion search experiments.
在本文中，我们报告了由钛/铝双层制造的集总元素动态电感探测器（LEKIDs）的电（暗）特性，该探测器设计用于$W$波段（75-110 GHz）的宽带吸收。这些探测器是未来Canfranc轴子探测实验（CADEx）中量子色动力学轴子搜索实验的原型，该实验要求在低光学背景下的亚$10^{-19} text{W}/sqrt{text{Hz}}$灵敏度。我们将马蒂斯-巴丁分析与噪声光谱相结合，以确定探测器参数的温度依赖性，以确定电噪声等效功率（NEP）。电气NEP的最小测量值为$sim 3 times 10^{-19} text{W}/sqrt{text{Hz}}$。在测量的温度范围内，我们发现准粒子的寿命偏离了预期的BCS复合定律。我们的分析表明，非平衡弛豫是由超导间隙的空间不均匀性和声子扩散效应控制的。这项工作为在$W$波段实现适合暗物质轴子搜索实验的超灵敏探测器设定了路线图。
{"title":"Dark Characterization of Ti/Al LEKIDs for the Search of Axions in the $W$-Band","authors":"Victor Rollano;Alejandro Pascual Laguna;David Rodriguez;Martino Calvo;Maria Teresa Magaz;Daniel Granados;Alessandro Monfardini;Alicia Gomez","doi":"10.1109/TASC.2026.3664493","DOIUrl":"https://doi.org/10.1109/TASC.2026.3664493","url":null,"abstract":"In this article, we report the electrical (dark) characterization of lumped-element kinetic inductance detectors (LEKIDs) fabricated from a titanium/aluminum bilayer and designed for broadband absorption in the <inline-formula><tex-math>$W$</tex-math></inline-formula>-band (75–110 GHz). These detectors are prototypes for future quantum chromodynamics axion search experiments within the Canfranc axion detection experiment (CADEx), which demand sub-<inline-formula><tex-math>$10^{-19} text{W}/sqrt{text{Hz}}$</tex-math></inline-formula> sensitivities under low optical backgrounds. We combine a Mattis–Bardeen analysis to the temperature dependence of the detector parameters with noise spectroscopy to determine the electrical noise equivalent power (NEP). The minimum measured value for the electrical NEP is <inline-formula><tex-math>$sim 3 times 10^{-19} text{W}/sqrt{text{Hz}}$</tex-math></inline-formula>. Across the measured temperature range, we find that quasiparticle lifetime deviates from the expected BCS recombination law. Our analysis suggests that nonequilibrium relaxation is governed by spatial inhomogeneities in the superconducting gap and phonon diffusion effects. This work sets the road-map to achieve suitable and ultra-sensitive detectors in the <inline-formula><tex-math>$W$</tex-math></inline-formula>-band for dark matter axion search experiments.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 6","pages":"1-7"},"PeriodicalIF":1.8,"publicationDate":"2026-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11407985","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147362479","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, a high spatial resolution distributed fiber optic strain sensing system, OFDR (optical frequency domain reflectometry), was used to monitor the strain of a dipole superconducting magnet coil during the cooling, excitation, and quenching processes. We studied the strain detection of the magnet structure using fiber optic strain sensors installed at different positions inside and on the surface of the magnet. The study shows that the strain results of the distributed fiber optic sensor at liquid helium were consistent with those of strain gauges with bridges. The distributed fiber optic strain sensing system can optimize the structural design of dipole superconducting magnets by detecting the global mechanical performance of the system. It can also indicate a comprehensive understanding of their mechanical behavior. The distributed strain sensing system will become an intelligent solution for detecting the strain of dipole superconducting magnets for structural health monitoring.
{"title":"The Distributed Strain Measurement of Dipole Superconducting Magnet Coil Based on OFDR Distributed Fiber Optic Sensor","authors":"Yongjie Zhang;Canjie Xin;Zhengnan Han;Mingzhi Guan","doi":"10.1109/TASC.2026.3664365","DOIUrl":"https://doi.org/10.1109/TASC.2026.3664365","url":null,"abstract":"In this study, a high spatial resolution distributed fiber optic strain sensing system, OFDR (optical frequency domain reflectometry), was used to monitor the strain of a dipole superconducting magnet coil during the cooling, excitation, and quenching processes. We studied the strain detection of the magnet structure using fiber optic strain sensors installed at different positions inside and on the surface of the magnet. The study shows that the strain results of the distributed fiber optic sensor at liquid helium were consistent with those of strain gauges with bridges. The distributed fiber optic strain sensing system can optimize the structural design of dipole superconducting magnets by detecting the global mechanical performance of the system. It can also indicate a comprehensive understanding of their mechanical behavior. The distributed strain sensing system will become an intelligent solution for detecting the strain of dipole superconducting magnets for structural health monitoring.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 5","pages":"1-4"},"PeriodicalIF":1.8,"publicationDate":"2026-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147299606","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Following the publication of [1], the authors identified an error in the author list. Diego Perini has therefore been removed from the author list with agreement of all authors.
{"title":"Corrections to “Status on the Development of the Nb3Sn 12 T Falcon Dipole for the FCC-hh”","authors":"Riccardo Umberto Valente;Amalia Ballarino;Andrea Bersani;Michela Bracco;Sergio Burioli;Barbara Caiffi;Ernesto De Matteis;Stefania Farinon;Andrea Gagno;Filippo Levi;Samuele Mariotto;Riccardo Musenich;Daniel Novelli;Arsenio Palmisano;Alessandra Pampaloni;Marco Prioli;Nicola Sala;Massimo Sorbi;Stefano Sorti;Marco Statera;Gianluca Vernassa","doi":"10.1109/TASC.2025.3645888","DOIUrl":"https://doi.org/10.1109/TASC.2025.3645888","url":null,"abstract":"Following the publication of [1], the authors identified an error in the author list. Diego Perini has therefore been removed from the author list with agreement of all authors.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 2","pages":"1-1"},"PeriodicalIF":1.8,"publicationDate":"2026-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11407930","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147299712","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-17DOI: 10.1109/TASC.2026.3665667
Ebrahim Forati;Brandon W. Langley;Ani Nersisyan;Reza Molavi
The precise engineering of electromagnetic couplings is paramount for constructing scalable and high-fidelity superconducting quantum processors. While essential for orchestrating qubit operations, these couplings also present significant design challenges, including the mitigation of crosstalk and the management of environmental decoherence. A clear and unified theoretical framework is therefore crucial for the design, simulation, and analysis of these complex quantum circuits. This article presents a comprehensive theoretical treatment of the fundamental electromagnetic coupling mechanisms in superconducting devices. Starting from first principles, we formulate the equations of motion and derive the input–output relations for canonical systems, including a single resonator coupled to a multiport microwave network, interacting resonators, and coupled transmission lines. We review rigorous definitions for key parameters such as the energy decay rate ($kappa$) and the dimensionless coupling coefficient ($zeta$) and connect these formalisms to practical methods of parameter extraction from electromagnetic simulations. This work provides a rigorous and pedagogical foundation for understanding and modeling linear electromagnetic interactions, serving as a vital resource for the development of advanced superconducting quantum hardware.
{"title":"On the Electromagnetic Couplings in Superconducting Qubit Circuits","authors":"Ebrahim Forati;Brandon W. Langley;Ani Nersisyan;Reza Molavi","doi":"10.1109/TASC.2026.3665667","DOIUrl":"https://doi.org/10.1109/TASC.2026.3665667","url":null,"abstract":"The precise engineering of electromagnetic couplings is paramount for constructing scalable and high-fidelity superconducting quantum processors. While essential for orchestrating qubit operations, these couplings also present significant design challenges, including the mitigation of crosstalk and the management of environmental decoherence. A clear and unified theoretical framework is therefore crucial for the design, simulation, and analysis of these complex quantum circuits. This article presents a comprehensive theoretical treatment of the fundamental electromagnetic coupling mechanisms in superconducting devices. Starting from first principles, we formulate the equations of motion and derive the input–output relations for canonical systems, including a single resonator coupled to a multiport microwave network, interacting resonators, and coupled transmission lines. We review rigorous definitions for key parameters such as the energy decay rate (<inline-formula><tex-math>$kappa$</tex-math></inline-formula>) and the dimensionless coupling coefficient (<inline-formula><tex-math>$zeta$</tex-math></inline-formula>) and connect these formalisms to practical methods of parameter extraction from electromagnetic simulations. This work provides a rigorous and pedagogical foundation for understanding and modeling linear electromagnetic interactions, serving as a vital resource for the development of advanced superconducting quantum hardware.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 7","pages":"1-19"},"PeriodicalIF":1.8,"publicationDate":"2026-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147362567","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-17DOI: 10.1109/TASC.2026.3665923
Alejandro Pascual Laguna;Victor Rollano;Aimar Najarro-Fiandra;David Rodriguez;Maria T. Magaz;Daniel Granados;Alicia Gomez
This work presents Ti/Al bilayer microwave kinetic inductance detectors (MKIDs) based on lens-coupled spiral absorbers as the quasi-optical coupling mechanism for millimeter-wavelength radiation detection. From simulations, the lens-coupled absorbers provide a 70% lens aperture efficiency in both polarizations over an octave band with a spiral array absorber and over 10% relative bandwidth with a single spiral. We have fabricated and measured two devices with bare Ti/Al MKIDs: a $3times 3$$,mathrm{c}mathrm{m}$ chip with 9 pixels to characterize the optical response at $85 ,mathrm{G}mathrm{Hz}$ of the two variations of the absorber; and a large format demonstrator with 253 spiral-array pixels showing potential toward a large format millimeter-wavelength camera. We estimate a sensitivity of $1 ,mathrm{m}mathrm{K}mathrm{/}sqrt{mathrm{Hz}}$ and a 95% detector yield.
{"title":"Millimeter-Wavelength Lens-Absorber-Coupled Ti/Al Kinetic Inductance Detectors","authors":"Alejandro Pascual Laguna;Victor Rollano;Aimar Najarro-Fiandra;David Rodriguez;Maria T. Magaz;Daniel Granados;Alicia Gomez","doi":"10.1109/TASC.2026.3665923","DOIUrl":"https://doi.org/10.1109/TASC.2026.3665923","url":null,"abstract":"This work presents Ti/Al bilayer microwave kinetic inductance detectors (MKIDs) based on lens-coupled spiral absorbers as the quasi-optical coupling mechanism for millimeter-wavelength radiation detection. From simulations, the lens-coupled absorbers provide a 70% lens aperture efficiency in both polarizations over an octave band with a spiral array absorber and over 10% relative bandwidth with a single spiral. We have fabricated and measured two devices with bare Ti/Al MKIDs: a <inline-formula><tex-math>$3times 3$</tex-math></inline-formula> <inline-formula><tex-math>$,mathrm{c}mathrm{m}$</tex-math></inline-formula> chip with 9 pixels to characterize the optical response at <inline-formula><tex-math>$85 ,mathrm{G}mathrm{Hz}$</tex-math></inline-formula> of the two variations of the absorber; and a large format demonstrator with 253 spiral-array pixels showing potential toward a large format millimeter-wavelength camera. We estimate a sensitivity of <inline-formula><tex-math>$1 ,mathrm{m}mathrm{K}mathrm{/}sqrt{mathrm{Hz}}$</tex-math></inline-formula> and a 95% detector yield.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 6","pages":"1-8"},"PeriodicalIF":1.8,"publicationDate":"2026-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147440552","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Understanding the weak thermal links in supporting legs of transition edge sensors (TES) is crucial for developing highly sensitive bolometers used in cosmic microwave background detection. Conventional current-biased differential resistance measurements under varying temperature (R-T) are commonly used to characterize the resistance (R) and critical temperature (Tc) of TES. However, this method often encounters some phenomena: the bias current will affect the transition temperature obtained during Tb drop testing, as well as the obtained shape of the transition region. This behavior stems from the weak thermal links of TES under current bias, limiting R-T method to providing only rough information about the TES transition regime sometimes. The detailed and accurate performance parameters typically obtained via voltage-biased current-voltage I–V measurements using superconducting quantum interference devices (SQUIDs). In fact, the positive electro-thermal feedback induced by current bias contains valuable insights into the device’s intrinsic properties. This work focuses on elaborating the underlying mechanism: by analyzing the current-induced suppression of measured transition temperature in R-T measurements, we extract key parameters including thermal conductance (G), thermal exponent (n), Tc, and saturation power (Psat). This study provides intuitive calculations and visualizations of the electro-thermal behaviors induced by current bias in TES devices and offers a simple and rapid complementary tool for electro-thermal parameter extraction. For batch TES fabrication, it can serve as a pre-screening tool to improve the efficiency of subsequent high-precision SQUID-based I–V characterization.
{"title":"Unraveling Current-Bias-Induced Transition Discrepancy in Transition-Edge Sensors in R-T Tests and Establishing a Reliable Characterizing Method","authors":"Qing Yu;Yongping Li;Guanhua Gao;Yu Xu;Kaiyong He;Mingjun Cheng;Zhengwei Li;Shibo Shu;Guodong Chen;Wei Chen","doi":"10.1109/TASC.2026.3664997","DOIUrl":"https://doi.org/10.1109/TASC.2026.3664997","url":null,"abstract":"Understanding the weak thermal links in supporting legs of transition edge sensors (TES) is crucial for developing highly sensitive bolometers used in cosmic microwave background detection. Conventional current-biased differential resistance measurements under varying temperature (<italic>R-T</i>) are commonly used to characterize the resistance (<italic>R)</i> and critical temperature (<italic>T</i><sub>c</sub>) of TES. However, this method often encounters some phenomena: the bias current will affect the transition temperature obtained during <italic>T</i><sub>b</sub> drop testing, as well as the obtained shape of the transition region. This behavior stems from the weak thermal links of TES under current bias, limiting <italic>R-T</i> method to providing only rough information about the TES transition regime sometimes. The detailed and accurate performance parameters typically obtained via voltage-biased current-voltage <italic>I–V</i> measurements using superconducting quantum interference devices (SQUIDs). In fact, the positive electro-thermal feedback induced by current bias contains valuable insights into the device’s intrinsic properties. This work focuses on elaborating the underlying mechanism: by analyzing the current-induced suppression of measured transition temperature in <italic>R-T</i> measurements, we extract key parameters including thermal conductance (<italic>G</i>), thermal exponent (<italic>n</i>), <italic>T</i><sub>c</sub>, and saturation power (<italic>P</i><sub>sat</sub>). This study provides intuitive calculations and visualizations of the electro-thermal behaviors induced by current bias in TES devices and offers a simple and rapid complementary tool for electro-thermal parameter extraction. For batch TES fabrication, it can serve as a pre-screening tool to improve the efficiency of subsequent high-precision SQUID-based <italic>I–V</i> characterization.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 7","pages":"1-6"},"PeriodicalIF":1.8,"publicationDate":"2026-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147362569","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-16DOI: 10.1109/TASC.2026.3665130
Kerr Smith;Alireza Sadeghi;Mohammad Yazdani-Asrami;Euan McGookin;Wenjuan Song
Losses generated by high temperature superconducting (HTS) tapes are a source of heat load in the powertrain of superconducting-driven electric aircraft. This study employs machine learning (ML) techniques to estimate ripple losses of HTS tapes, which occur on the DC side of the powertrain and place notable demands on the cryogenic cooling system. Ripple losses generated by 6, 12, and 24 pole (pulse) rectification were investigated under switching frequencies of typical AC/DC converters in electric aircraft. Fast, data-driven estimation of ripple losses in the HTS tapes are introduced to overcome the high computational cost of finite element method (FEM)-based methods. Four ML techniques, Gaussian process regression (GPR), decision tree, ensemble learning (ENS), and artificial neural network, are assessed to demonstrate the effectiveness of the best method. As current ripple may propagate through the full drivetrain, the choice of ML technique is a technical requirement, and rapid, tape-level loss prediction is a primary step for condition monitoring and health assessment of HTS devices in cryo-electric aircraft. Training data were generated using a validated 2D H-formulation FEM-based model developed in COMSOL multiphysics, which included all metallic sublayers to account for their high-frequency effects. Results showed GPR achieves the highest accuracy, with a mean relative error of 1.8% and goodness of fit percentage value of 99.997%. The model is then updated to a two-tape stack model to show the generalizability of the proposed GPR model, also show high-accuracy results. ML techniques reduced computation time dramatically compared with FEM simulation, with test times between 51 and 139 ms for the full data range, compared to 10–30 min for only the frequency range data.
{"title":"Machine Learning-Based Estimation of Ripple Losses in High Temperature Superconductors for Cryo-Electric Aviation Applications","authors":"Kerr Smith;Alireza Sadeghi;Mohammad Yazdani-Asrami;Euan McGookin;Wenjuan Song","doi":"10.1109/TASC.2026.3665130","DOIUrl":"https://doi.org/10.1109/TASC.2026.3665130","url":null,"abstract":"Losses generated by high temperature superconducting (HTS) tapes are a source of heat load in the powertrain of superconducting-driven electric aircraft. This study employs machine learning (ML) techniques to estimate ripple losses of HTS tapes, which occur on the DC side of the powertrain and place notable demands on the cryogenic cooling system. Ripple losses generated by 6, 12, and 24 pole (pulse) rectification were investigated under switching frequencies of typical AC/DC converters in electric aircraft. Fast, data-driven estimation of ripple losses in the HTS tapes are introduced to overcome the high computational cost of finite element method (FEM)-based methods. Four ML techniques, Gaussian process regression (GPR), decision tree, ensemble learning (ENS), and artificial neural network, are assessed to demonstrate the effectiveness of the best method. As current ripple may propagate through the full drivetrain, the choice of ML technique is a technical requirement, and rapid, tape-level loss prediction is a primary step for condition monitoring and health assessment of HTS devices in cryo-electric aircraft. Training data were generated using a validated 2D H-formulation FEM-based model developed in COMSOL multiphysics, which included all metallic sublayers to account for their high-frequency effects. Results showed GPR achieves the highest accuracy, with a mean relative error of 1.8% and goodness of fit percentage value of 99.997%. The model is then updated to a two-tape stack model to show the generalizability of the proposed GPR model, also show high-accuracy results. ML techniques reduced computation time dramatically compared with FEM simulation, with test times between 51 and 139 ms for the full data range, compared to 10–30 min for only the frequency range data.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 7","pages":"1-12"},"PeriodicalIF":1.8,"publicationDate":"2026-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147440640","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-16DOI: 10.1109/TASC.2026.3665392
Daniel Dutcher;Peter Dow;Shannon M. Duff;Shawn W. Henderson;Johannes Hubmayr;Bradley R. Johnson;Michael J. Link;Tammy J. Lucas;Michael D. Niemack;Yudai Seino;Rita F. Sonka;Suzanne Staggs;Yuhan Wang;Kaiwen Zheng
The Simons Observatory (SO) is a new suite of cosmic microwave background telescopes in the Chilean Atacama Desert with an extensive science program spanning cosmology, galactic and extragalactic astrophysics, and particle physics. SO will survey the millimeter-wave sky over a wide range of angular scales using six spectral bands across three types of dichroic, polarization-sensitive transition-edge sensor (TES) detector modules: Low-frequency modules with bandpasses centered near 30 and 40 GHz, mid-frequency (MF) modules near 90 and 150 GHz, and ultra-high-frequency (UHF) modules near 220 and 280 GHz. In total, 25 UHF detector modules, each containing 1720 optically coupled TESs connected to microwave SQUID multiplexing readout, have now been produced. This work summarizes the predeployment characterization of these detector modules in laboratory cryostats. Across all UHF modules, we find an average operable TES yield of 83%, equating to over 36 000 devices tested. The distributions of (220, 280) GHz saturation powers have medians of (24, 26) pW, near the centers of their target ranges. For both bands, the median optical efficiency is 0.6, the median effective time constant is 0.4 ms, and the median dark noise-equivalent power (NEP) is $sim$40 aW$/sqrt{mathbf {Hz}}$. The expected photon NEPs at (220, 280) GHz are (64, 99) aW$/sqrt{mathbf {Hz}}$, indicating that these detectors will achieve background-limited performance on the sky. In total, 39 UHF and MF detector modules are currently operating in fielded SO instruments, which are transitioning from the commissioning stage to full science observations.
西蒙斯天文台（SO）是位于智利阿塔卡马沙漠的一套新的宇宙微波背景望远镜，具有广泛的科学计划，涵盖宇宙学，银河系和星系外天体物理学以及粒子物理学。SO将使用三种类型的二色偏振敏感过渡边缘传感器（TES）探测器模块的六个光谱带在大范围的角度尺度上对毫米波天空进行调查：低频模块，带通中心接近30和40 GHz，中频（MF）模块接近90和150 GHz，超高频（UHF）模块接近220和280 GHz。目前共生产了25个UHF探测器模块，每个模块包含1720个光耦合TESs，连接到微波SQUID多路复用读出器。这项工作总结了这些探测器模块在实验室低温恒温器中的预部署特性。在所有UHF模块中，我们发现平均可操作TES产率为83%, equating to over 36 000 devices tested. The distributions of (220, 280) GHz saturation powers have medians of (24, 26) pW, near the centers of their target ranges. For both bands, the median optical efficiency is 0.6, the median effective time constant is 0.4 ms, and the median dark noise-equivalent power (NEP) is $sim$40 aW$/sqrt{mathbf {Hz}}$. The expected photon NEPs at (220, 280) GHz are (64, 99) aW$/sqrt{mathbf {Hz}}$, indicating that these detectors will achieve background-limited performance on the sky. In total, 39 UHF and MF detector modules are currently operating in fielded SO instruments, which are transitioning from the commissioning stage to full science observations.
{"title":"The Simons Observatory: Characterization of the 220/280 GHz TES Detector Modules","authors":"Daniel Dutcher;Peter Dow;Shannon M. Duff;Shawn W. Henderson;Johannes Hubmayr;Bradley R. Johnson;Michael J. Link;Tammy J. Lucas;Michael D. Niemack;Yudai Seino;Rita F. Sonka;Suzanne Staggs;Yuhan Wang;Kaiwen Zheng","doi":"10.1109/TASC.2026.3665392","DOIUrl":"https://doi.org/10.1109/TASC.2026.3665392","url":null,"abstract":"The Simons Observatory (SO) is a new suite of cosmic microwave background telescopes in the Chilean Atacama Desert with an extensive science program spanning cosmology, galactic and extragalactic astrophysics, and particle physics. SO will survey the millimeter-wave sky over a wide range of angular scales using six spectral bands across three types of dichroic, polarization-sensitive transition-edge sensor (TES) detector modules: Low-frequency modules with bandpasses centered near 30 and 40 GHz, mid-frequency (MF) modules near 90 and 150 GHz, and ultra-high-frequency (UHF) modules near 220 and 280 GHz. In total, 25 UHF detector modules, each containing 1720 optically coupled TESs connected to microwave SQUID multiplexing readout, have now been produced. This work summarizes the predeployment characterization of these detector modules in laboratory cryostats. Across all UHF modules, we find an average operable TES yield of 83%, equating to over 36 000 devices tested. The distributions of (220, 280) GHz saturation powers have medians of (24, 26) pW, near the centers of their target ranges. For both bands, the median optical efficiency is 0.6, the median effective time constant is 0.4 ms, and the median dark noise-equivalent power (NEP) is <inline-formula><tex-math>$sim$</tex-math></inline-formula>40 aW<inline-formula><tex-math>$/sqrt{mathbf {Hz}}$</tex-math></inline-formula>. The expected photon NEPs at (220, 280) GHz are (64, 99) aW<inline-formula><tex-math>$/sqrt{mathbf {Hz}}$</tex-math></inline-formula>, indicating that these detectors will achieve background-limited performance on the sky. In total, 39 UHF and MF detector modules are currently operating in fielded SO instruments, which are transitioning from the commissioning stage to full science observations.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 6","pages":"1-5"},"PeriodicalIF":1.8,"publicationDate":"2026-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147440575","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-13DOI: 10.1109/TASC.2026.3664278
J. P. T. Templet;S. L. Fretwell;A. Marino;R. Cantor;A. Hall;C. Bray;C. Stone-Whitehead;I. Kim;F. Ponce;W. Van De Pontseele;K. G. Leach;S. Friedrich
The beryllium electron capture in superconducting tunnel junctions (BeEST) experiment uses superconducting tunnel junction (STJ) sensors to search for physics beyond the standard model with recoil spectroscopy of the $mathbf {^{7}}$Be EC decay into $mathbf {^{7}}$Li. A pulsed UV laser is used to calibrate the STJs throughout the experiment with $sim$20 meV precision. Phase-III of the BeEST experiment revealed a systematic calibration discrepancy between STJs. We found these artifacts to be caused by resistive crosstalk and by variable substrate heating due to intensity variations of the calibration laser. For phase-IV of the BeEST experiment, we have removed the crosstalk by designing the STJ array so that each pixel has its own ground wire. We now also use a more stable UV laser for calibration. The new STJ arrays were fabricated at STAR Cryoelectronics and tested at Lawrence Livermore National Laboratory and Facility for Rare Isotope Beams. They have the same high energy resolution of $sim$1–2 eV in the energy range of interest below 100 eV as before, and significantly reduce the presence of both calibration artifacts. We discuss the design changes and the STJ array performance for the next phase of the BeEST experiment.
{"title":"Next Generation Ta-STJ Sensor Arrays for BSM Physics Searches","authors":"J. P. T. Templet;S. L. Fretwell;A. Marino;R. Cantor;A. Hall;C. Bray;C. Stone-Whitehead;I. Kim;F. Ponce;W. Van De Pontseele;K. G. Leach;S. Friedrich","doi":"10.1109/TASC.2026.3664278","DOIUrl":"https://doi.org/10.1109/TASC.2026.3664278","url":null,"abstract":"The beryllium electron capture in superconducting tunnel junctions (BeEST) experiment uses superconducting tunnel junction (STJ) sensors to search for physics beyond the standard model with recoil spectroscopy of the <inline-formula><tex-math>$mathbf {^{7}}$</tex-math></inline-formula>Be EC decay into <inline-formula><tex-math>$mathbf {^{7}}$</tex-math></inline-formula>Li. A pulsed UV laser is used to calibrate the STJs throughout the experiment with <inline-formula><tex-math>$sim$</tex-math></inline-formula>20 meV precision. Phase-III of the BeEST experiment revealed a systematic calibration discrepancy between STJs. We found these artifacts to be caused by resistive crosstalk and by variable substrate heating due to intensity variations of the calibration laser. For phase-IV of the BeEST experiment, we have removed the crosstalk by designing the STJ array so that each pixel has its own ground wire. We now also use a more stable UV laser for calibration. The new STJ arrays were fabricated at STAR Cryoelectronics and tested at Lawrence Livermore National Laboratory and Facility for Rare Isotope Beams. They have the same high energy resolution of <inline-formula><tex-math>$sim$</tex-math></inline-formula>1–2 eV in the energy range of interest below 100 eV as before, and significantly reduce the presence of both calibration artifacts. We discuss the design changes and the STJ array performance for the next phase of the BeEST experiment.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 6","pages":"1-5"},"PeriodicalIF":1.8,"publicationDate":"2026-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147299696","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-13DOI: 10.1109/TASC.2026.3664442
E. Cucchetti;H. Geoffray;S. Beaumont;W. B. Doriese;M. Durkin;C. Kirsch;R. Denis-Jung;O. Maisonnave;A. Panglosse;P. Peille;K. Sakai;S. J. Smith;N. A. Wakeham
The X-ray integral field unit (X-IFU), on the future European X-ray observatory NewAthena, will perform high-resolution imaging spectroscopy over an array of 1 504 transition-edge sensors operated at 55 mK. Its readout is performed via time-division multiplexing at a few megahertz, which relies on fast (but not instantaneous) switching between pixels of the same column. Differences in the currents of consecutive rows lead to signal-dependent transients in the readout. These transients, and how they settle before sampling of the final row signal, are in turn governed by the open-loop bandwidths in the system. Limitations of the bandwidths smear the transients and contaminate the settling of photon pulses, resulting in a frequency- and amplitude-dependent error on the output signal. Switching transients have thus ultimately a direct impact on the instrument's energy scale. Although the origin of these perturbations is well-understood, quantifying their end-to-end impact on performance remains challenging. We compare here experimental data with simulations to assess the accuracy of numerical predictions. We also present an end-to-end analysis of nonlinearity in the X-IFU energy scale due to switching transients, and compare it against current performance budget allocations. These simulations show that the X-IFU can meet its energy scale requirements.
{"title":"Time-Division Multiplexing Switching Transients and Bandwidth Effects on the X-Ray Integral Field Unit Readout Performance","authors":"E. Cucchetti;H. Geoffray;S. Beaumont;W. B. Doriese;M. Durkin;C. Kirsch;R. Denis-Jung;O. Maisonnave;A. Panglosse;P. Peille;K. Sakai;S. J. Smith;N. A. Wakeham","doi":"10.1109/TASC.2026.3664442","DOIUrl":"https://doi.org/10.1109/TASC.2026.3664442","url":null,"abstract":"The X-ray integral field unit (X-IFU), on the future European X-ray observatory <italic>NewAthena</i>, will perform high-resolution imaging spectroscopy over an array of 1 504 transition-edge sensors operated at 55 mK. Its readout is performed via time-division multiplexing at a few megahertz, which relies on fast (but not instantaneous) switching between pixels of the same column. Differences in the currents of consecutive rows lead to signal-dependent transients in the readout. These transients, and how they settle before sampling of the final row signal, are in turn governed by the open-loop bandwidths in the system. Limitations of the bandwidths smear the transients and contaminate the settling of photon pulses, resulting in a frequency- and amplitude-dependent error on the output signal. Switching transients have thus ultimately a direct impact on the instrument's energy scale. Although the origin of these perturbations is well-understood, quantifying their end-to-end impact on performance remains challenging. We compare here experimental data with simulations to assess the accuracy of numerical predictions. We also present an end-to-end analysis of nonlinearity in the X-IFU energy scale due to switching transients, and compare it against current performance budget allocations. These simulations show that the X-IFU can meet its energy scale requirements.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 6","pages":"1-6"},"PeriodicalIF":1.8,"publicationDate":"2026-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147362390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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