Stripline Detectors Research Articles

Artificial intelligence-driven shimming for parallel high field nuclear magnetic resonance

Rapid drug development requires a high throughput screening technology. NMR could benefit from parallel detection but is hampered by technical obstacles. Detection sites must be magnetically shimmed to ppb uniformity, which for parallel detection is precluded by commercial shimming technology. Here we show that, by centering a separate shim system over each detector and employing deep learning to cope with overlapping non-orthogonal shimming fields, parallel detectors can be rapidly calibrated. Our implementation also reports the smallest NMR stripline detectors to date, based on an origami technique, facilitating further upscaling in the number of detection sites within the magnet bore.

Synchronous SFQ Address Encoder for Superconductor Detector Arrays

With the advances in superconductor detectors and single flux quantum (SFQ) logic circuits, megapixel imagers have become possible. Various detectors such as superconducting stripline detectors (SSLD), kinetic inductance detectors, nanowire single-photon detectors have quite matured in terms of speed and performance. However, scaling of the read-out electronics is still a challenge. We propose an SFQ based synchronous address encoder to read-out the response of an SSLD array. The encoder circuit provides two sets of outputs at each clock period: one is the time-division multiplexed, serial data output, and the other is the synchronized address output associated with the time-multiplexed data. Thus, the number of connections to the room temperature is substantially reduced. We experimentally demonstrate a 2-bit encoder. Then, we present the scalability of the circuit to larger arrays and show the simulation results of a 4-bit encoder, which is suitable to read-out a 16 × 16 detector array.

Real-time stress evolution during laser surface line hardening at varying maximum surface temperatures using synchrotron X-ray diffraction

Multiple laser surface line hardening experiments on flat samples, made of tempering steel SAE 4140, were carried out under variation of the maximum control temperature in the range of 850 °C to 1150 °C at the sample surface. For each temperature, time resolved X-ray diffraction measurements using synchrotron radiation were performed at beamline P05@PETRA III at DESY (Deutsches Elektronen Synchrotron) in Hamburg, Germany. The samples were line hardened using a 4 kW High Power Diode Laser unit at a constant laser feed of 800 mm/min with a specific laser optics under pyrometer control of the maximum surface temperature. A special designed process chamber with 4 symmetrically attached fast silicon micro strip line detectors allows for stress analysis during the process according to the sin2ψ method in single exposure mode with a measurement frequency of 50 Hz. As a result of the time resolved analyses the elastic strains were separated from thermal ones and near surface local stress evolutions, longitudinal and transverse to the laser track direction in the center of the processed zone, were determined. The in situ experiments were complemented by high spatially resolved post-process residual stress analyses using conventionally generated X-rays and by metallographic investigations. The results are carefully discussed regarding mechanisms of local stress formation during the laser hardening process and their dependence on the maximum control temperature. The temporal stress course during laser surface line hardening is presented for the first time in both surface parallel directions, where temperature differences in the process zone lead to significant differences in the resulting residual stress profiles. In addition to the common validation of process simulations by comparison with experimentally determined data from the final state after processing, e.g. the resulting local residual stresses, the current work provides real-time data from in situ experiments during laser surface hardening for the validation of temporal stress courses of numerical process simulations.

SFQ Parallel Encoders Promising for Video Imaging With Superconductor Stripline Detectors

We report demonstration of a readout circuit with high-throughput single flux quantum (SFQ) based encoders for a large-scale video imaging system with a conventional frame rate. The encoders are fully parallel and integrated on the same chip as linear arrays of serially connected superconductor stripline detectors (SSLDs), superconducting quantum interference device (SQUID) based comparators, and SFQ synchronizers. Mutual coupling of parallel SSLDs and SQUID-based comparators allows the use of only one dc bias line; it is possible to use thousands of SSLDs without increasing the bias current or number of bias ports. To achieve crosstalk-free readout, the serially connected SSLDs are separated by low-pass filters or large inductors. We experimentally demonstrated crosstalk-free readout including SFQ parallel encoders from 1-D or 2-D serially connected SSLD arrays.

Electrodynamic theory for the operation principle of a superconducting kinetic inductance stripline detector

Generation and transmission of voltage signals in a kinetic inductance detector made of a superconducting nanowire stripline is investigated on the basis of superconducting electromagnetism. We show that electric signals traveling along the stripline in this detector can be regarded as a Swihart mode. An equation which can describe the generation and transmission of voltage pulses in this detector is derived. A pair of voltage pulses with opposite polarities are created when a spatiotemporal variation in the density of the superconducting condensate occurs in a small region of this superconducting nanowire. The voltage pulses propagate along the stripline in the directions opposite to each other with the Swihart velocity. The characteristic of the radiation detector named current-biased kinetic inductance detector (CB-KID) is well described by our model.

In Situ Battery Spectroscopy: A Novel Approach to Investigate Unmodified Working Batteries

We develop a new system and capability for performing in situ electrochemical nuclear magnetic resonance (EC-NMR) spectroscopy on batteries with the aim to measure spectroscopic data during battery cycling. In traditional battery NMR, the battery under investigation is placed inside a solenoid coil. The metal battery electrodes, essential to the battery operation, are necessarily also placed inside the coil, which lowers the sensitivity and resolution of the resulting data. In the case of electrodes that are thick compared to the radiofrequency skin depth at the NMR frequency, in situ NMR may be impossible. In that case, the rf field is effectively screened by the metal electrodes and is prevented from imparting the magnetic energy necessary for NMR to the interior of the battery. Our system, in contrast, uses an internal stripline detector. The essential 2-dimensional stripline detector is built into the battery itself during fabrication, and allows high quality NMR data to be obtained in situ during battery operation regardless of the thickness of the electrodes. Initial 7Li NMR results on pouch cell batteries with a variety of cathode materials (LiFePO4, LiCoO2, and LiNi5Mg3Co2O2) versus a graphite anode are discussed. The EC-NMR system can be used to study any NMR active nucleus of interest and so is versatile in studying a variety of battery types. This technique has the potential to allow investigation of many poorly-understood battery chemistries, and provides the means to monitor the creation and consumption of chemical species during actual battery operation conditions. Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525. This work was funded by the Sandia Exploratory Express LDRD program.

Development of an Advanced Circuit Model for Superconducting Strip Line Detector Arrays

This work is partially supported by TUBITAK with the project number 114E099 and JSPS KAKENHI with the grant number 23226019.

Stripline 75As NMR Study of Epitaxial III–V Semiconductor Al0.5Ga0.5As

We have carried out 75As NMR experiments on a single 5 μm thick epitaxial layer of metal organic chemical vapor deposition (MOCVD) AlxGa1–xAs, with x = 0.522, using a novel stripline based NMR setup. Different arsenic surroundings in the lattice give rise to five As[AlnGa4–n] sites with (n = 0–4). By mounting a thin film of Al0.522Ga0.478As in a home-built NMR probe with rotation stage and stripline detector, we could successfully distinguish different arsenic nearest neighbors coordinations. Furthermore, we were able to observe various 75As quadrupolar tensor orientations for each As[AlnGa4–n] coordination, which gives us a unique insight into the structure of this material. The individual resonances for each of these coordinations appear to be very broad, as a result of the variation in the local symmetry due to the distribution of aluminum and gallium over the lattice. In particular, the NMR resonance of one orientation of the As[Al2Ga2] site is strongly broadened. The line widths prove to be larger than predicted on the basis of the (distribution in) quadrupolar interaction parameters obtained in a previous study of powdered AlxGa1–xAs films (P. J. Knijn et al. Phys. Chem. Chem. Phys. 2010, 12, 11517–11535). In Density Functional Theory (DFT) based calculations, these wider distributions in quadrupolar interaction parameters can be explained by local variations in the first coordination sphere of arsenic, which become apparent when the internal structure is relaxed before quantum mechanical calculations of the Electric Field Gradient Tensors (EFGs). A detailed simulation of the NMR line intensities, taking the actual NMR excitation parameters into account, prove the absence of any kind of local or long-range order in the occupation of the Al/Ga sites in the lattice.

Parallel superconducting strip-line detectors: reset behaviour in the single-strip switch regime

Superconducting strip-line detectors (SSLDs) are an important emerging technology for the detection of single molecules in time-of-flight mass spectrometry (TOF-MS). We present an experimental investigation of a SSLD laid out in a parallel configuration, designed to address selected single strip-lines operating in the single-strip switch regime. Fast laser pulses were tightly focused onto the device, allowing controllable nucleation of a resistive region at a specific location and study of the subsequent device response dynamics. We observed that in this regime, although the strip-line returns to the superconducting state after triggering, no effective recovery of the bias current occurs, in qualitative agreement with a phenomenological circuit simulation that we performed. Moreover, from theoretical considerations and by looking at the experimental pulse amplitude distribution histogram, we have the first confirmation of the fact that the phenomenological London model governs the current redistribution in these large area devices also after detection events.

Current distribution in a parallel configuration superconducting strip-line detector

Superconducting detectors based on parallel microscopic strip-lines are promising candidates for single molecule detection in time-of-flight mass spectrometry. The device physics of this configuration is complex. In this letter, we employ nano-optical techniques to study the variation of current density, count rate, and pulse amplitude transversely across the parallel strip device. Using the phenomenological London theory, we are able to correlate our results to a non-uniform current distribution between the strips, governed by the London magnetic penetration depth. This fresh perspective convincingly explains anomalous behaviour in large area parallel superconducting strip-line detectors reported in previous studies.

Fastin situphase and stress analysis during laser surface treatment: A synchrotron x-ray diffraction approach

An in situ stress analysis by means of synchrotron x-ray diffraction was carried out during laser surface hardening of steel. A single exposure set-up that based on a special arrangement of two fast silicon strip line detectors was established, allowing for fast stress analysis according to the sin(2)ψ x-ray analysis method. For the in situ experiments a process chamber was designed and manufactured, which is described in detail. First measurements were carried out at the HZG undulator imaging beamline (IBL, beamline P05) at the synchrotron storage ring PETRA III, DESY, Hamburg (Germany). The laser processing was carried out using a 6 kW high power diode laser system. Two different laser optics were compared, a Gaussian optic with a focus spot of ø 3 mm and a homogenizing optic with a rectangular spot dimension of 8 × 8 mm(2). The laser processing was carried out using spot hardening at a heating-/cooling rate of 1000 K/s and was controlled via pyrometric temperature measurement using a control temperature of 1150 °C. The set-up being established during the measuring campaign allowed for this first realization data collection rates of 10Hz. The data evaluation procedure applied enables the separation of thermal from elastic strains and gains unprecedented insight into the laser hardening process.

A 2 × 2 mm2 superconducting strip-line detector for high-performance time-of-flight mass spectrometry

We present the fabrication and characterization of the latest generation of superconducting strip-line detectors (SSLD) for application in time-of-flight mass spectrometer (TOF MS) of heavy molecules. The SSLD is realized in the parallel strip-line configuration to achieve a 2 × 2 mm2 sensitive area. The parallel SSLD is mounted in a TOF MS and tested at 4.2 K under bombardment of lysozyme molecules. The detector exhibits output pulses with rise and fall times of 500 ps and 2.3 ns respectively. We also present measurements of the time evolution during the acquisition of the singly and doubly charged monomers and singly charged dimers peaks in the mass spectrum. We argue that the observed behavior proves that parallel SSLD can perform charge state discrimination. The achievement of a 2 × 2 mm2 sensitive area with an output pulse rise time in the region of the sub-nanosecond and a fall time of a few nanoseconds is a milestone in the development of superconducting detectors for TOF MS applications because it addresses important issues such as high mass resolution and high-throughput analysis.

Parallel Superconducting Strip-Line Detectors for Time-of-flight Mass Spectrometry

We present our achievements in the development of superconducting strip-line detectors (SSLDs) with parallel configuration for application in time-of-flight mass spectrometry. We have fabricated 2×2 mm2 SSLDs by electron beam nano-lithography. In spite of the large area, the detector has a fast time response. To our knowledge our device is the largest cryogenic detector for macromolecules with nanosecond temporal response. Based on the obtained results, our simulations show that the presented parallel SSLD design should be able to cover an area of 4×2 mm2 while keeping the signal pulse risetime below 1 ns.

Operation of superconducting nano-stripline detector (SSLD) mounted on cryogen-free cryostat

Abstract Recently, various types of superconducting detectors have been applied to time-of-flight mass spectrometers (TOF MS) because they can achieve 100% detection efficiency for a wide mass range from atoms to huge biomolecules. The wide mass range coverage is impossible with conventional microchannel plate (MCP) ion detectors. Superconducting stripline detectors (SSLD) that consist of several hundreds of superconducting nanostrips with a width of

Thicker, more efficient superconducting strip-line detectors for high throughput macromolecules analysis

Fast detectors with large area are required in time-of-flight mass spectrometers for high throughput analysis of biological molecules. We fabricated and characterized subnanosecond 1×1 mm2 NbN superconducting strip-line detectors. The influence of the strip-line thickness on the temporal characteristics and efficiency of the detector for the impacts of keV accelerated molecules is investigated. We find that the increase of thickness improves both efficiency and response time. In the thicker sample we achieved a rise time of 380 ps, a fall time of 1.38 ns, and a higher count rate. The physics involved in this behavior is investigated.

1 mm ultrafast superconducting stripline molecule detector

Superconducting stripline detectors (SSLDs) are promising for detecting keV molecules at nanosecond response times and with mass-independent detection efficiency. However, a fast response time is incompatible with practical centimeter detector size. A parallel configuration of striplines provides a means to address this problem. Experimental results and simulation for promisingly large 1-mm-square parallel niobium SSLDs show that nanosecond pulses are produced by superconducting-normal transition within only one of the parallel striplines instead of cascade switching of all the parallel striplines. Successful detection of a series of multimers of immunoglobulin G up to 584 kDa supports the mass-independent efficiency for mass spectrometry.

Development of Superconducting Strip Line Detectors (SSLDs) for Time-of-Flight Mass Spectrometers (TOF-MS)

We have succeeded in obtaining mass spectra of peptides or proteins with superconducting stripline detectors (SSLDs) which have a meander structure similar to so called superconducting single photon detectors (SSPDs). Encouraged by the previous results on the NbN-SSLD for time-of-flight mass spectrometry (TOF-MS), we fabricated other SSLDs from Nb or YBCO thin films. Because of a small London penetration depth, the Nb-based SSLD is expected to have a fast response time. Another promising superconducting material is YBCO which has a critical temperature around 90 K. Operation at higher temperatures will make a noticeable impact on the practical application to MS. The optimum SSLD design for MS should be totally different from that of SSPD in order to realize both of a meaningful sensitive area for high detection efficiency and a reasonably-fast response time for high mass resolution. We made SSLDs with a variety of stripline structures from different materials. One of the key factors for the SSLD design is kinetic inductance. In this study, TOF-MS spectra of biomolecules are presented, and the relationship between SSLD geometry and their performance is discussed.

Niobium superconducting strip line detectors (SSLD) for time-of-flight mass spectroscopy (TOF-MS)

Superconducting strip line detectors (SSLDs) have the same nanostructure as so called Superconducting Single Photon Detectors (SSPDs) for ultrafast photon detection. However, the optimum SSLD design for mass spectrometers (MS) should be totally different from that of SSPD in order to realize meaningful sensitive area and reasonably fast response time for mass-independent detection. Recently, we have succeeded in obtaining mass spectra of Angiotensin I (MW = 1296 Da) at an energy of 17.5 keV using Nb-SSLDs. Since it is known that in NbN SSLDs the response time of SSLDs is governed by kinetic inductance, Nb films with a short London penetration depth have an advantage over NbN. In this study, the relationship between the detector structures and their performance is reported.

Detection area enlargement of superconducting stripline detectors for time-of-flight mass spectrometry

Superconducting stripline detectors (SSLDs) have promise as fast molecule detectors for time-of-flight mass spectrometry (TOF-MS). In this study, we have prepared NbN-SSLDs consisting of a meander structure with a thickness of 10 nm and a sensor size of 200 × 200 μm 2, which is larger than our previous sensor size of 50 × 50 μm 2 and the largest ever reported as NbN-SSLDs. Mass spectra were successfully acquired for Angiotensin I and lysozyme by using a time-to-digital converter (TDC). It was confirmed that the counting rate and hence the statistics of mass spectra were considerably improved, while the rise time of output pulse was kept to less than 1 ns by adjusting the kinetic inductance of the striplines. With the high statistics, we have investigated the bias current dependence of detection efficiency.

Subnanosecond time response of large-area superconducting stripline detectors for keV molecular ions

A large-area (200×200 μm2) superconducting stripline detector based on a parallel configuration of superconducting Nb nanowires is presented. We show that the parallel configuration provides a smart way to control the physical nonequilibrium state induced by the molecular impacts, which allows realizing large sensitive area and subnanosecond response at the same time. The experiments were carried out with molecular ions radiation in a keV energy range. The observed rise time was below 400 ps and the relaxation time was 500 ps, the best in this class of superconducting molecular detectors.