We present an experiment designed to determine directly the symmetry of the pairing state in the cuprate superconductors.From the magnetic IIux modulation of YBCO-Pb dc SQUIDs, we determine the spatial anisotropy of the phase of the order parameter in single crystals of YBCO. The experimental results are complicated by SQUID asymmetries and the trapping of magnetic vortices, but taken as ã hole give rather strong evidence for a phase shift of n that is predicted for the d"2 y2 pairing state. This is further corroborated by single junction modulation measurements. PACS numbers: 74.50.+r, 74.20.Mn, 74.72.BkSince the discovery of the high temperature cuprate superconductors, much eflort has concentrated on the determination of the superconducting pairing mechanism and in particular the symmetry of the pairing state. Although many symmetries are allowed in principle [1], there is strong experimental evidence that the spin pairing is singlet [2], suggesting an s-wave or d-wave state. There are also indications that spin fluctuations, thought to be important in the normal state, may also be responsible for the superconductivity.

No abstract

SummaryWe have developed a prototype X-ray microcalorimeter spectrometer with high energy resolution for use in X-ray microanalysis. The microcalorimeter spectrometer system consists of a superconducting transition-edge sensor X-ray microcalorimeter cooled to an operating temperature near 100 mK by a compact adiabatic demagnetization refrigerator, a superconducting quantum interference device current amplifier followed by pulse-shaping amplifiers and pileup rejection circuitry, and a multichannel analyser with computer interface for the real-time acquisition of X-ray spectra. With the spectrometer mounted on a scanning electron microscope, we have achieved an instrument response energy resolution of better than 10 eV full width at half-maximum (FWHM) over a broad energy range at real-time output count rates up to 150 s ¹1. Careful analysis of digitized X-ray pulses yields an instrument-response energy resolution of 7 . 2 Ϯ 0 . 4 eV FWHM at 5 . 89 keV for Mn Ka 1,2 X-rays from a radioactive 55 Fe source, the best reported energy resolution for any energy-dispersive detector.

Framework Release 3.0 Background Since the release of the last edition of the NIST Smart Grid Framework and Roadmap for Interoperability Standards (Release 2.0), 1 in February 2012, significant technological advances in smart grid infrastructure have been implemented, supported by standards development across the entire smart grid arena. Examples include widespread deployment of wirelesscommunication power meters, availability of customer energy usage data through the Green Button initiative, remote sensing for determining real-time transmission and distribution status, and protocols for electric vehicle charging. The first release of the NIST Framework and Roadmap for Smart Grid Interoperability Standards (Release 1.0) 2 was published in January 2010. Release 3.0 updates NIST's ongoing efforts to facilitate and coordinate smart grid interoperability standards development and smart grid-related measurement science and technology, including the evolving and continuing NIST relationship with the Smart Grid Interoperability Panel (SGIP) public-private partnership. Over the last decade, Congress and the Administration have outlined a vision for the smart grid and have laid the policy foundation upon which it is being built. The Energy Independence and Security Act of 2007 (EISA) codified the policy of the United States to modernize the nation's electricity transmission and distribution system to create a smart electric grid. 3 The American Recovery and Reinvestment Act of 2009 (ARRA) accelerated the development of smart grid technologies, investing $4.5 billion for electricity delivery and energy reliability activities to modernize the electric grid and implement demonstration and deployment programs (as authorized under Title XIII of EISA). 4 5 The president, in his 2011 and 2012 State of the Union Addresses, reiterated his vision for a clean energy economy, 6 and he underscored the Administration's commitment in the "Blueprint for a Secure Energy Future." 7

Time-of-flight mass spectrometry-most notably matrix-assisted laser-desorption-ionization time-of-flight (MALDI-TOF) spectrometry-is an important class of techniques for the study of proteins and other biomolecules. Although these techniques provide excellent performance for masses up to about 20,000 daltons, there has been limited success in achieving good mass resolution at higher masses. This is because the sensitivity of the microchannel plate (MCP) detectors used in most systems decreases rapidly with increasing particle mass, limiting the utility of MCP detectors for very large masses. It has recently been proposed that cryogenic particle detectors may provide a solution to these difficulties. Cryogenic detectors measure the thermal energy deposited by the particle impact, and thus have a sensitivity that is largely independent of particle mass. Recent experiments have demonstrated the sensitivity of cryogenic particle detectors to single biomolecules, a quantum efficiency several orders of magnitude larger than the MCP detectors, and sensitivity to masses as large as 750,000 daltons. Here we present results demonstrating an order of magnitude better energy resolution than previous measurements, allowing direct determination of particle charge state during acceleration. Although application of these detectors to practical mass spectrometry will require further development of the detectors and cryogenics, these detectors can be used to elucidate the performance-limiting processes that occur in such systems.

We investigate limits on the thermal-response time of superconducting transition-edge microcalorimeters. For operation at 0.1 K, we show that the lower limit on the response time of a superconducting transition-edge microcalorimeter is of order 1 μs due to the heat diffusion time, electrical instabilities, the amplifier noise, and the critical current of the superconducting film. The response time is not limited by self-heating effects and is independent of the intended photon energy. However, design constraints associated with the inductance of the bias circuit make it difficult to achieve the fastest response times for devices with heat capacities high enough for x-ray and gamma-ray detection.

This document has been prepared by the Cyber-Physical Systems Public Working Group (CPS PWG), an open public forum established by the National Institute of Standards and Technology (NIST) to support stakeholder discussions and development of a framework for cyber-physical systems. This document is a freely available contribution of the CPS PWG and is published in the public domain. Certain commercial entities, equipment, or materials may be identified in this document in order to describe a concept adequately. Such identification is not intended to imply recommendation or endorsement by the CPS PWG (or NIST), nor is it intended to imply that these entities, materials, or equipment are necessarily the best available for the purpose. All registered trademarks or trademarks belong to their respective organizations.

We have developed a new type of x-ray detector based on a superconducting transition-edge thermometer operated near 100 mK. A superconducting quantum interference device is used to measure the current through the thermometer, and negative electrothermal feedback is used to improve the energy resolution and shorten the thermal time constant. We have used a detector mounted on a scanning electron microscope to measure the energy of titanium Kα (4.5 keV) fluorescence x rays with a resolution better than 14 eV full width at half-maximum. Using two other devices, we have measured an energy resolution for Joule heat pulses of 2.6 eV at 1 keV and 0.2 eV at 4 eV, the best reported for any calorimeter. An electrical noise equivalent power of 3×10−18 W/√Hz was also measured, suggesting the use of these detectors as infrared bolometers.