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  • richardmitnick 1:36 pm on September 12, 2017 Permalink | Reply
    Tags: , NIST, NIST Researchers Revolutionize the Atomic Force Microscope, PTIR-Photothermal induced resonance   

    From NIST: “NIST Researchers Revolutionize the Atomic Force Microscope” 


    NIST

    September 12, 2017

    Ben Stein
    benjamin.stein@nist.gov
    (301) 975-2763

    `
    Close-up schematic view of a nanoscale AFM probe integrated with an optical resonator to expand the probe’s capabilities. The waveguide acts as an optical version of a “whispering gallery” that allows certain frequencies of light to resonate.
    Credit: NIST

    Most measuring instruments are limited by the tradeoff between how precisely and how rapidly a measurement is made: the more precise the measurement, the longer it takes. But because many phenomena occurring at the nanoscale are both rapid and tiny, they demand a measuring system that can capture their precise details in both time and space.

    Taking up that challenge, researchers at the National Institute of Standards and Technology (NIST) have redesigned the detection system at the heart of the atomic force microscope (AFM). A premier tool of the nanoworld, the AFM uses a small probe, or tip, to map the submicroscopic hills and valleys that define the surface of materials, along with other properties, at the nanometer scale. Although the AFM has already revolutionized the understanding of nanostructures, scientists are now eager to study nanoscale phenomena, such as the folding of proteins or the diffusion of heat, which happen too quickly and generate changes too small to be accurately measured by existing versions of the microscope.

    By fabricating an extremely lightweight AFM probe and combining it with a nanoscale device that converts minuscule deflections of the probe into large changes of an optical signal inside a waveguide, the NIST researchers have broken new ground: Their AFM system measures rapid changes in structure with high precision.

    2
    Illustration of a newly fabricated atomic force microscope (AFM) probe integrated with an optical, disk-shaped resonator. Combined with a technique called photothermal induced resonance (PTIR), which uses infrared light to examine a material’s composition, the incorporation of the resonator enables the probe to make high-precision measurements of minuscule, rapid changes in a material.
    Credit: NIST

    The achievement takes the AFM into a new realm, enabling the instrument to measure time-varying nanoscale processes that may change as quickly as ten billionths of a second. “This is truly a transformational advance,” said NIST scientist Andrea Centrone.

    Centrone, Vladimir Aksyuk, and their colleagues employed the new AFM capabilities in experiments using photothermal induced resonance (PTIR), a technique that combines the acuity of an AFM with the ability to determine the composition of materials using infrared light.

    With the new AFM-PTIR system, the scientists measured with high precision the rapid, but minute expansion of individual microcrystals heated by a light pulse. The microcrystals examined by the team belong to a class of materials known as metal-organic frameworks (MOFs). These materials contain nanosized pores that act as miniature sponges, which can store gas and serve as drug delivery containers, among other applications.

    Accurate knowledge of how well MOFs conduct heat is crucial for designing these materials for specific applications. However, most MOFs are microcrystals, which are too small for conventional instruments to measure their thermal conductivity. Instead, the team used the new AFM-PTIR system to record how long it took for the MOF crystals to cool down and return to their original size after they were heated by the light pulse and thermally expanded. The researchers then used that information to determine the thermal conductivity of individual MOF microcrystals, a feat that had never before been accomplished.

    The AFM system designed by Aksyuk and his colleagues features two key elements. First, the researchers shrunk and slimmed down the AFM’s probe, a small cantilever that acts like a spring, deflecting and vibrating when a sample exerts a force on it. Fashioned in the NanoFab at NIST’s Center for Nanoscale Science and Technology (CNST), the new probe weighs a mere trillionth of a gram. The minuscule mass enabled the probe to respond more quickly to a tiny force or displacement such as the one induced by the thermal expansion of the MOF the team examined.

    The researchers integrated the cantilever with a miniature disk-shaped waveguide that acts like an optical version of a whispering gallery. Just as a whispering gallery allows certain frequencies of sound waves to travel freely around a dome, the waveguide allows certain frequencies of light to resonate, circulating around the disk.

    The AFM cantilever and the disk are separated by a mere 150 nanometers. That’s close enough that tiny motions of the cantilever change the resonant frequencies in the disk, in effect transforming the small mechanical motion of the AFM probe into a large change in optical signal. Although scientists have combined optical cavities with other measuring tools, the team’s system is the first to integrate this kind of optical device in an AFM.

    Centrone, Aksyuk and their colleagues described the findings in a recent publication in Nano Letters .

    Aksyuk and his collaborators painstakingly designed, fabricated and tested the system using an array of nanofabrication tools at the CNST. The new AFM-PTIR system can record a displacement as small as a trillionth of a meter that occurs over a time scale as short as 10 billionths of a second. The team now plans to work on increasing the speed of the PTIR technique and using the probe to make measurements in water, a more suitable environment for examining biological samples.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    NIST Campus, Gaitherberg, MD, USA

    NIST Mission, Vision, Core Competencies, and Core Values

    NIST’s mission

    To promote U.S. innovation and industrial competitiveness by advancing measurement science, standards, and technology in ways that enhance economic security and improve our quality of life.
    NIST’s vision

    NIST will be the world’s leader in creating critical measurement solutions and promoting equitable standards. Our efforts stimulate innovation, foster industrial competitiveness, and improve the quality of life.
    NIST’s core competencies

    Measurement science
    Rigorous traceability
    Development and use of standards

    NIST’s core values

    NIST is an organization with strong values, reflected both in our history and our current work. NIST leadership and staff will uphold these values to ensure a high performing environment that is safe and respectful of all.

    Perseverance: We take the long view, planning the future with scientific knowledge and imagination to ensure continued impact and relevance for our stakeholders.
    Integrity: We are ethical, honest, independent, and provide an objective perspective.
    Inclusivity: We work collaboratively to harness the diversity of people and ideas, both inside and outside of NIST, to attain the best solutions to multidisciplinary challenges.
    Excellence: We apply rigor and critical thinking to achieve world-class results and continuous improvement in everything we do.

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  • richardmitnick 3:12 pm on July 13, 2017 Permalink | Reply
    Tags: , INFO-Integrated Near-Field Optoelectronic, , NIST, The probe tip also functions as a light source for measuring how a sample responds to illumination, The system uses gallium nitride (GaN) nanowires as the basis of the nanoprobe   

    From NIST: “Sub-microscopic LEDs Shed New Light on Advanced Materials” 

    NIST

    July 12, 2017
    Media Contact
    Ben Stein
    benjamin.stein@nist.gov
    (301) 975-2763

    Technical Contact
    Kris A. Bertness
    kris.bertness@nist.gov
    (303) 497-5069

    One of the persistent challenges in 21st century metrology is the need to measure ever-more-detailed properties of ever-smaller things, from microchip features to subcomponents of biological cells. That’s why, four years ago, a team of NIST scientists patented (link is external) the design for a nanoscale probe system that can simultaneously measure the shape, electrical characteristics, and optical response of sample regions a few tens of nanometers (nm, billionths of a meter) wide. 100 nm is about one-thousandth the width of a human hair.

    1
    Matt Brubaker (left) and Kris Bertness with the chamber in which nanowires are formed. No image credit.

    Now the researchers from NIST’s Physical Measurement Laboratory are closing in on a working prototype. The newest version of the device, which has a probe tip that functions as an ultra-tiny LED “spotlight,” holds great promise for identifying cancer-prone tissue, testing materials for improved solar cells, and providing a new way to put circuits on microchips, among other uses.

    The Integrated Near-Field Optoelectronic (INFO) system has the general configuration of an atomic force microscope (AFM), in which a probe tip on the end of a tiny cantilever beam passes a few nanometers over the surface of a sample, recording exact details of its morphology. But the metal-plated INFO probe also serves as a transmitter that projects microwaves into the sample as well as a receiving antenna that detects the altered microwaves coming back out. The nature of that alteration reveals electrical and chemical properties of the material.

    The system uses gallium nitride (GaN) nanowires as the basis of the nanoprobe. “In addition to being a semiconductor, gallium nitride is mechanically very strong,” says group leader Kris Bertness. “It’s a ceramic, kind of like a high-performance kitchen knife. It’s tough as nails.” As a result, the probe – a few hundred nanometers wide at the point and about 4 micrometers (millionths of a meter) long – doesn’t lose its sharpness, which is critical to performance.

    But GaN has another major advantage: It is the material widely used in light-emitting diodes (LEDs). So, in addition to serving as an AFM and microwave transmitter/receiver, the probe tip also functions as a light source for measuring how a sample responds to illumination.

    3
    This image shows the NIST logo made from glowing nanowire LEDs. While the color of the nanowires in the image looks blue, they are actually emitting in the ultraviolet with a wavelength of approximately 380 nm. The other two images, from a scanning electron microscope, show the overall structure of the nanowires.

    Recently, the team found a way to increase the light output of their probe 100-fold by experimenting with the placement and configuration of “n-type” silicon-doped GaN (which has an excess of free electrons) and “p-type” magnesium-doped GaN, which has a surplus of “holes” – areas where electrons are missing. When an electron and hole combine, they release energy in the form of light, as in LEDs. (See illustration.) Conversely, when light strikes the material in a solar cell, its absorbed energy separates electrons and holes, prompting a current to flow.

    “INFO will allow you to illuminate your sample with near-field resolution (tens of nanometers) and also see if the electrical properties of your sample at that exact same location have changed using the microwave sensing method,” Bertness says. “That’s important, for example, in investigating solar cell materials. With this probe, you can see very locally how that conductivity changes when you illuminate it. Similarly, people are working on photodetectors that are based on polycrystalline materials. They would like to know how the grain boundaries differ in their response to light.”

    Integrated circuit fabricators could use INFO to look for defects and identify the exact location of specific dopant areas in ultra-small features. “The channels are now getting so small, about 15 nm or smaller, that where the dopant atoms actually sit matters,” Bertness says. “Nobody used to have to care about that, but now they might be able to sense those locations because you could optically excite the carriers in and out of the dopant atoms and sense the change with the microwave reflection.

    “Another benefit is that the near-ultraviolet light from the probe tip is very tightly focused, so it can also be used to do much higher resolution lithography than you can do in your standard clean room. In conventional lithography, a beam is directed down at the material surface and directed onto specific exposure areas by using a mask. The INFO probe, however, can use a process called ‘direct write’ that doesn’t require a mask. You could program your probe to move in a specific pattern and coordinate that motion with when the light comes on and off, and you would expose just what you needed.”

    There are numerous potential biological applications. For example, there is some evidence that the mechanical stiffness of collagen – the ubiquitous protein that provides support for all parts of the body – may be related to whether cancer cells are more likely to recur or metastasize. “What medical researchers do now is use AFMs to go in and measure the stiffness of tissue,” Bertness says. “But while they’re doing that, they have no way of knowing when the probe is on collagen or something else. INFO might be able to help. Collagen has very interesting, unique optical properties. So, if scientists could illuminate the sample at the same time they’re doing stiffness measurements, they could determine what kind of tissue the probe is over.”

    Increasing the LED light output from the probe required a prolonged research effort involving the development of several key capabilities. One of the most difficult problems was developing selective-area nanowire growth, which is a process through which nanowire growth can be prescribed at specified locations. Identification and control over the crystal polarity that develops as the GaN wires grow was found to be critical in developing this capability. Another was determining the right geometry and formation conditions for the p-type section of the probe.

    “Initially we tried to fabricate the p-type section as an axial extension of the nanowire probe, however the high-temperature growth conditions required for this type of structure precluded effective p-type doping. In principle, a better p-section could be obtained at lower growth temperatures, however an increased radial growth rate caused nanowires to merge together in our LED test samples,” says project scientist Matt Brubaker. “By synthesizing isolated nanowires via selective area nanowire growth, we could avoid the merging issue and use radial growth to our advantage in synthesizing a core-shell geometry.” After achieving the 100-fold increase in light intensity, “we want to start making these probes and applying them,” Bertness says. “We need to do demonstrations and get some publications out there. That will help us look for potential researchers who could benefit from this technology.”

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    NIST Campus, Gaitherberg, MD, USA

    NIST Mission, Vision, Core Competencies, and Core Values

    NIST’s mission

    To promote U.S. innovation and industrial competitiveness by advancing measurement science, standards, and technology in ways that enhance economic security and improve our quality of life.
    NIST’s vision

    NIST will be the world’s leader in creating critical measurement solutions and promoting equitable standards. Our efforts stimulate innovation, foster industrial competitiveness, and improve the quality of life.
    NIST’s core competencies

    Measurement science
    Rigorous traceability
    Development and use of standards

    NIST’s core values

    NIST is an organization with strong values, reflected both in our history and our current work. NIST leadership and staff will uphold these values to ensure a high performing environment that is safe and respectful of all.

    Perseverance: We take the long view, planning the future with scientific knowledge and imagination to ensure continued impact and relevance for our stakeholders.
    Integrity: We are ethical, honest, independent, and provide an objective perspective.
    Inclusivity: We work collaboratively to harness the diversity of people and ideas, both inside and outside of NIST, to attain the best solutions to multidisciplinary challenges.
    Excellence: We apply rigor and critical thinking to achieve world-class results and continuous improvement in everything we do.

     
  • richardmitnick 9:51 am on July 2, 2017 Permalink | Reply
    Tags: , MEMS - microelectromechanical systems technologies, NIST   

    From NIST: “Intrinsic Properties: The Secret Lives of Accelerometers” 

    NIST

    May 30, 2017

    Media Contact
    Ben Stein
    benjamin.stein@nist.gov
    (301) 975-2763

    Technical Contact
    Michael Gaitan
    michael.gaitan@nist.gov
    (301) 975-2070

    1
    http://www.industrial-electronics.com/DAQ/industrial_electronics/input_devices_sensors_transducers_transmitters_measurement/Accelerometers.html

    Accelerometers — devices that measure change in velocity — are built into automobiles, airplanes, cell phones, pacemakers, and scores of other products. They warn of potentially destructive vibration in industrial equipment, buildings, and bridges; register seismic shocks; and guide missiles to their targets.

    Increasingly, they are miniaturized using microelectromechanical systems (MEMS) technologies with component dimensions on the order of micrometers, and simultaneously register acceleration in all three axes of three-dimensional space. Because errors are additive when calculating velocity from acceleration, even minor errors in output can have very serious consequences.

    Yet when three-axis sensitivities and cross-axis sensitivities of a digital three-axis* device are tested at different calibration laboratories, the measurements can vary substantially depending on factors that can be difficult to determine, but often arise from errors with alignment of the test equipment, the internal alignment of the accelerometers in the device, or both.

    Now NIST scientists have devised a methodology designed to reduce or eliminate those differences by characterizing intrinsic properties of an accelerometer – those that are unique to it irrespective of the way it is mounted or tested — thus making possible accurate interlaboratory comparisons.

    “Determination of intrinsic properties is part of NIST’s larger effort to help industry develop standard testing protocols for the new MEMS-based device technologies, which do not exist at present,” says Michael Gaitan of NIST’s Physical Measurement Laboratory, which is working in partnership with the MEMS and Sensors Industry Group (MSIG) and the Institute of Electrical and Electronics Engineers. “Testing was reported by MSIG to be as much as half the cost of manufacturing for these sorts of devices. Manufacturers can’t reduce the cost of physical fabrication very much. But they can find savings in the way they package, test, and calibrate the devices.”

    When MEMS-based, three-axis accelerometers are tested, they are typically mounted on a gimbal system and rotated about three axes — x, y, and z — with measurements taken in different orientations. The measurements are formatted in a three-by-three grid, called a “cross-sensitivity matrix,” used by manufacturers to evaluate device performance. It specifies the relation between the acceleration response along the gimbal axes to the response along the axes of the device under test (DUT).

    That process, however, assumes that the DUT’s three axes are perfectly orthogonal – at right angles to each other – and that the device has been mounted in perfect alignment with the gimbal axes, which are themselves perfectly aligned. And in the case of testing accelerometer packages after they have been integrated into products, such as smart phones, it assumes that the package was installed in exact alignment with the axes of the phone case. But none of those conditions is guaranteed, and slight deviations in any of the variables can explain why measurements of the same test unit made at different laboratories produce different values.

    “So instead of using the cross-sensitivity matrix alone,” Gaitan says, “we’re defining the device as having intrinsic properties in which the axes of the device are not assumed to be completely orthogonal. There might be some variation in their alignment.”

    In NIST’s measurement protocol, the DUT is mounted on the position and rate table which very accurately rotates the device in specific gradations through 360 degrees on each of the gimbal’s three axes while measuring the device response at each interval. The protocol reveals the DUT’s internal axis alignment, the magnitude of response of each axis in different orientations, and its “signal offset” – the constant amount by which measured readings differ from the “true” value.

    With that information, a central standards laboratory such as NIST could fully characterize the intrinsic properties of one or more DUTs and distribute the devices to other labs, which would use them to compare results and determine, for example, whether readings were skewed because of instrument-related measurement errors.

    Earlier this year, NIST acquired a new position and rate table large enough to permit measurements on entire products that have accelerometers installed. “Our initial gimbal system was a smaller instrument that was useful for making static measurements,” Gaitan says.

    “But now we can make dynamic measurements on objects as large as a cell phone. We can set it to steady-state rotation like a record player, and we can accelerate the rotation rate. That will enable us to make measurements above the 1g acceleration of gravity and measure acceleration by rotation.”

    • Although it is called a “three-axis accelerometer,” the device in fact contains three separate accelerometers, each of which measures velocity change along one axis. Those signals are merged to register movement in three dimensions.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    NIST Campus, Gaitherberg, MD, USA

    NIST Mission, Vision, Core Competencies, and Core Values

    NIST’s mission

    To promote U.S. innovation and industrial competitiveness by advancing measurement science, standards, and technology in ways that enhance economic security and improve our quality of life.
    NIST’s vision

    NIST will be the world’s leader in creating critical measurement solutions and promoting equitable standards. Our efforts stimulate innovation, foster industrial competitiveness, and improve the quality of life.
    NIST’s core competencies

    Measurement science
    Rigorous traceability
    Development and use of standards

    NIST’s core values

    NIST is an organization with strong values, reflected both in our history and our current work. NIST leadership and staff will uphold these values to ensure a high performing environment that is safe and respectful of all.

    Perseverance: We take the long view, planning the future with scientific knowledge and imagination to ensure continued impact and relevance for our stakeholders.
    Integrity: We are ethical, honest, independent, and provide an objective perspective.
    Inclusivity: We work collaboratively to harness the diversity of people and ideas, both inside and outside of NIST, to attain the best solutions to multidisciplinary challenges.
    Excellence: We apply rigor and critical thinking to achieve world-class results and continuous improvement in everything we do.

     
  • richardmitnick 1:19 pm on July 1, 2017 Permalink | Reply
    Tags: Boulder, JILA, , NIST, PTB,   

    From PTB: “The sharpest laser in the world” 

    PTB – The National Metrology Institute of Germany

    29.06.2017

    Erika Schow
    +49 531 592-9314
    erika.schow@ptb.de

    Imke Frischmuth
    +49 531 592-9323imke.frischmuth@ptb.de
    Secretariat
    Karin Conring
    Tel+49 531 592-3006
    Fax: +49 531 592-3008
    karin.conring@ptb.de

    Address
    Physikalisch-Technische Bundesanstalt
    Bundesallee 100
    38116 Braunschweig

    Contact
    Dr. Thomas Legero,
    PTB Department 4.3,
    Quantum Optics and Unit of Length
    +49 (0)531 592-4306,
    thomas.legero@ptb.de

    The Physikalisch-Technische Bundesanstalt has developed a laser with a linewidth of only 10 mHz.

    1
    One of the two silicon resonators (photo: PTB)

    No one had ever come so close to the ideal laser before: theoretically, laser light has only one single color (also frequency or wavelength). In reality, however, there is always a certain linewidth. With a linewidth of only 10 mHz, the laser that researchers from the Physikalisch-Technische Bundesanstalt (PTB) have now developed together with US researchers from JILA, a joint institute of the National Institute of Standards and Technology (NIST) and the University of Colorado, Boulder, has established a new world record. This precision is useful for various applications such as optical atomic clocks, precision spectroscopy, radioastronomy and for testing the theory of relativity. The results have been published in the current issue of Physical Review Letters.

    Lasers were once deemed a solution without problems – but that is now history. More than 50 years have passed since the first technical realization of the laser, and we cannot imagine how we could live without them today. Laser light is used in numerous applications in industry, medicine and information technologies. Lasers have brought about a real revolution in many fields of research and in metrology – or even made some new fields possible in the first place.

    One of a laser’s outstanding properties is the excellent coherence of the emitted light. For researchers, this is a measure for the light wave’s regular frequency and linewidth. Ideally, laser light has only one fixed wavelength (or frequency). In practice, the spectrum of most types of lasers can, however, reach from a few kHz to a few MHz in width, which is not good enough for numerous experiments requiring high precision.

    Research has therefore focused on developing ever better lasers with greater frequency stability and a narrower linewidth. Within the scope of a nearly 10-year-long joint project with the US colleagues from JILA in Boulder, Colorado, a laser has now been developed at PTB whose linewidth is only 10 mHz (0.01 Hz), hereby establishing a new world record. “The smaller the linewidth of the laser, the more accurate the measurement of the atom’s frequency in an optical clock. This new laser will enable us to decisively improve the quality of our clocks”, PTB physicist Thomas Legero explains.

    In addition to the new laser’s extremely small linewidth, Legero and his colleagues found out by means of measurements that the emitted laser light’s frequency was more precise than what had ever been achieved before. Although the light wave oscillates approx. 200 trillion times per second, it only gets out of sync after 11 seconds. By then, the perfect wave train emitted has already attained a length of approx. 3.3 million kilometers. This length corresponds to nearly ten times the distance between the Earth and the moon.

    Since there was no other comparably precise laser in the world, the scientists working on this collaboration had to set up two such laser systems straight off. Only by comparing these two lasers was it possible to prove the outstanding properties of the emitted light.

    The core piece of each of the lasers is a 21-cm long Fabry-Pérot silicon resonator. The resonator consists of two highly reflecting mirrors which are located opposite each other and are kept at a fixed distance by means of a double cone. Similar to an organ pipe, the resonator length determines the frequency of the wave which begins to oscillate, i.e., the light wave inside the resonator. Special stabilization electronics ensure that the light frequency of the laser constantly follows the natural frequency of the resonator. The laser’s frequency stability – and thus its linewidth – then depends only on the length stability of the Fabry-Pérot resonator.

    The scientists at PTB had to isolate the resonator nearly perfectly from all environmental influences which might change its length. Among these influences are temperature and pressure variations, but also external mechanical perturbations due to seismic waves or sound. They have attained such perfection in doing so that the only influence left was the thermal motion of the atoms in the resonator. This “thermal noise” corresponds to the Brownian motion in all materials at a finite temperature, and it represents a fundamental limit to the length stability of a solid. Its extent depends on the materials used to build the resonator as well as on the resonator’s temperature.

    For this reason, the scientists of this collaboration manufactured the resonator from single-crystal silicon which was cooled down to a temperature of -150 °C. The thermal noise of the silicon body is so low that the length fluctuations observed only originate from the thermal noise of the dielectric SiO2/Ta2O5 mirror layers. Although the mirror layers are only a few micrometers thick, they dominate the resonator’s length stability. In total, the resonator length, however, only fluctuates in the range of 10 attometers. This length corresponds to no more than a ten-millionth of the diameter of a hydrogen atom. The resulting frequency variations of the laser therefore amount to less than 4 × 10–17 of the laser frequency.

    The new lasers are now being used both at PTB and at JILA in Boulder to further improve the quality of optical atomic clocks and to carry out new precision measurements on ultracold atoms. At PTB, the ultrastable light from these lasers is already being distributed via optical waveguides and is then used by the optical clocks in Braunschweig.

    “In the future, it is planned to disseminate this light also within a European network. This plan would allow even more precise comparisons between the optical clocks in Braunschweig and the clocks of our European colleagues in Paris and London”, Legero says. In Boulder, a similar plan is in place to distribute the laser across a fiber network that connects between JILA and various NIST labs.

    The scientists from this collaboration see further optimization possibilities. With novel crystalline mirror layers and lower temperatures, the disturbing thermal noise can be further reduced. The linewidth could then even become smaller than 1 mHz.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The Physikalisch-Technische Bundesanstalt, the National Metrology Institute of Germany, is a scientific and technical higher federal authority falling within the competence of the Federal Ministry for Economic Affairs and Energy.

    PTB is Germany’s highest authority when it comes to correct and reliable measurements. It is the supreme technical authority of the Federal Ministry for Economic Affairs and Energy (BMWi) and employs a total of approx. 1900 staff members. PTB operates an integrated Opens internal link in current windowquality management system which covers the four interlinked field of business.

     
  • richardmitnick 2:29 pm on June 24, 2017 Permalink | Reply
    Tags: , , NIST, SRM's -Standard Reference Materials   

    From NIST: ” Measurements Matter – How NIST Reference Materials Affect You” 

    NIST

    June 13, 2017
    Fran Webber

    In 2012, Consumer Reports announced startling findings—with potentially serious public health ramifications.

    The publication investigated arsenic levels in apple juice and rice and found levels of the toxin above those allowed in water by the Environmental Protection Agency. The articles pointed out that there were no rules about allowable levels for arsenic in food.

    The Food and Drug Administration responded by issuing a limit for arsenic levels in apple juice and, in 2016, for infant rice cereal . But the damage was already done.

    It’s a funny quirk of human psychology: we take the most important things for granted—until it all goes wrong.

    You probably don’t often question whether the food you buy in the grocery store is safe. Or if the lab where your doctor sends your samples accurately calculated your vitamin D levels.

    But imagine, for a moment, how much more difficult it would be to go about your daily life if you didn’t have the information those measurements provide.

    How would you decide what is safe and healthy to eat? How would you know if you were getting enough vitamin D or if your cholesterol levels were too high?

    That’s one of the big reasons NIST exists—to reduce uncertainty in our measurements and increase your confidence in the information you use to make important decisions in your daily life.

    And part of the way NIST does that is through Standard Reference Materials (SRMs).

    Standard Reference … what?

    The government has acronyms for seemingly everything. At NIST, one even has a registered trademark: SRM® is the “brand name” of our certified reference materials, the generic term for these vital tools. Many other organizations measure and distribute certified reference materials, but only NIST has SRMs.

    So what exactly is an SRM or certified reference material?


    NIST chemist Bob Watters provides an overview of how NIST’s standard reference materials, ranging from metal alloys to cholesterol samples, have helped industry make reliable measurements since the earliest days of the agency.

    It can be difficult to explain, because SRMs are actually a lot of different things. In fact, NIST sells more than 1,000 different types of SRMs, from gold nanoparticles to peanut butter .

    NIST has very carefully studied each of its SRMs, and it’s these characterizations, rather than the materials themselves, that customers pay for. SRMs serve a variety of purposes but are mostly used by other labs and members of industry to check their analytical measurements and to perform other kinds of quality-control tests.

    Steve Choquette, director of NIST’s Office of Reference Materials, says SRMs are like widgets, tools that provide a service or help you complete a task. In this case, SRMs give manufacturers access to a level of measurement accuracy they wouldn’t otherwise be able to obtain.

    “What an SRM really does is give our customers the highest quality measurements in a form they can easily use,” Choquette says.

    Peanut butter—SRM 2387—is an excellent example. NIST scientists know exactly how much fat, salt, sugar and other nutrients are in the peanut butter, and they’ve recorded those amounts on a certificate that’s sold with the SRM. When an SRM user measures the NIST peanut butter with his or her own instrument, he or she should get amounts that match the certificate. If not, the manufacturer knows the machine must be adjusted.

    NIST is a nonregulatory agency, which means it doesn’t set the rules for things like food and water safety. However, manufacturers frequently use NIST standards such as SRMs because they are a reliable, science-based means to demonstrating compliance with the rules set by regulatory agencies.

    Does your food measure up?

    Like the peanut butter SRM, many NIST SRMs are food products. These SRMs help the food industry comply with various U.S. food regulations such as those requiring nutrition facts labels. Regulators can be sure those labels are accurate when producers use SRMs to ensure their measurement instruments are properly calibrated.

    In the lab, Joe Katzenmeyer, senior scientist and strategic analytical manager at Land O’Lakes, uses the SRMs for nonfat milk powder, infant formula and meat homogenate (a canned pork and chicken mix).

    “We most often use NIST SRMs when developing a new testing procedure, and we need to know that a result is the ‘correct’ result,” Katzenmeyer said. “NIST values are established through a very thorough process and by labs across the country. This gives a high credibility to their established values.”

    And that’s how you can be confident in the nutrition facts labels, too, so you can make healthy decisions about what to eat.

    2
    NIST SRM 2385, spinach. Credit: K. Irvine/NIST

    But NIST food SRMs don’t just help you accurately count your carbs.

    Remember the concern about arsenic in apple juice and rice? NIST already had a rice flour SRM, but NIST researchers recently added measurements for different types of arsenic. And, NIST is in the process of making an SRM for apple juice that will include levels for various forms of arsenic as well. Government agencies, like the Food and Drug Administration, can use these SRMs to ensure that arsenic levels in the foods we eat are safe.

    And both health and safety are driving forces behind another type of NIST SRMs—those for dietary supplements.

    Marketers can make some pretty strong claims about their products. But do so-called “superfoods” like green tea or blueberries live up to the hype? The first step in finding out is to carefully measure the properties of these foods.

    That’s why NIST makes SRMs for green tea and blueberries, as well as multivitamins, St. John’s Wort and Ginkgo biloba, among others.

    A medical measurement marvel

    Nearly 74 million Americans have high levels of LDL cholesterol —that’s the bad kind. Those with high cholesterol have twice the risk of heart disease as those with normal levels.

    Keeping tabs on your cholesterol can be a matter of life and death. So, when you or your loved one goes to the doctor’s office to give a blood sample, how do you know the result you get is right?

    If you’re thinking it’s because of NIST SRMs, you’d be right! NIST sells a number of SRMs that lab techs use to calibrate clinical laboratory equipment.

    But SRMs don’t just help maintain the status quo. They also help drive innovation.

    A new SRM for monoclonal antibodies—a large class of drugs for treating cancer and autoimmune diseases, among other things—could make these life-saving treatments more widely available.

    Monoclonal antibodies are large protein molecules designed to bind to disease-causing cells or proteins, triggering a patient’s immune system to attack and clear them from the body. Sales of these drugs in the U.S. reached $50 billion in 2015.

    3

    NIST’s monoclonal antibody reference material, NIST RM 8671, is shipped in cryovials packaged in dry ice. It should be stored in a frozen state at -80 °C (-112 °F). Shown is a sample that underwent extensive round-robin testing by more than 100 collaborators before the biological material, donated by MedImmune, was certified as a NIST RM. Credit: NIST

    Manufacturing a monoclonal antibody drug on a large scale is complex and involves the use of genetically engineered cells that churn out large quantities of the molecule. Testing to make sure that the molecules are being made correctly happens at many points in the manufacturing process. The NIST SRM is an important tool for assuring the quality of these test methods and of the final product.

    And, since patents on many monoclonal antibodies are set to expire in the next several years, many anticipate a growing market for biosimilar—or generic—versions of the drugs. Generics could save patients billions of dollars by 2020 .

    But, this will mean a lot of testing and measurements to determine whether these generic versions are nearly identical to the branded versions. The NIST monoclonal antibody SRM could help with measurement challenges faced by researchers tasked with testing these drugs.

    Taking measurements to court

    In 1978, Michael Hanline was found guilty of murder in California. But Hanline always said he was innocent. Eventually, the California Innocence Project at California Western School of Law took up his case, and through DNA analysis, showed that Hanline was not the source of DNA found on key evidence.

    Hanline spent 36 years in prison. He is the longest-serving wrongfully convicted person in California history.

    When Hanline was convicted, the ability to evaluate DNA evidence didn’t yet exist. But today, it’s not uncommon to hear of cases where DNA evidence makes or breaks the case. And not just to exonerate the innocent. Far more often, DNA evidence helps law enforcement put away the right people the first time.

    NIST forensic DNA SRMs are crucial to this process. They help make sure that labs conducting forensic DNA analysis obtain accurate results. The Federal Bureau of Investigation requires that forensic DNA testing laboratories meet certain quality assurance standards. Labs must check their processes with a NIST SRM (or a reference material that traces back to NIST) every year or anytime they make substantial changes to their protocol.

    “The NIST DNA SRM we use in our lab is essential to ensure our analyses are reliable,” said Todd Bille, DNA technical leader at the Bureau of Alcohol, Tobacco, Firearms and Explosives. “With all the advances in the forensic community, NIST SRM 2391c is the only set of DNA samples that has what we need to make sure the analyses function properly in our hands. Our lab is also constantly evaluating new methods to handle DNA. Having this set of standard DNA samples allows us to be sure new methods don’t adversely affect the results.”

    Cementing quality control

    First of all, John Sieber wants you to know: There’s a difference between cement and concrete.

    “People get the two mixed up,” says Sieber, a NIST research chemist. “Cement is what you have before, and then you mix it with water and sand and gravel—aggregate, they call it—and you pour it into your sidewalk and it hardens through a chemical reaction and becomes concrete.”

    4
    NIST researcher John Sieber, concrete SRM development. Credit: copyright Earl Zubkoff

    Though you may have never given it a second thought, you no doubt interact with concrete on a daily basis as you drive to work, park your car in a garage, walk across the sidewalk to your office and sit at your desk in a high-rise building.

    “The human race is trying to cover the planet in concrete,” Sieber jokes.

    To make sure their product can withstand the tests of time, wear and weather, cement makers conform to certain quality standards. During the manufacturing process, cement makers test their products hourly. NIST SRMs are crucial to letting manufacturers know the results of their tests are accurate—and that they’re creating a high-quality product.

    NIST sells 15 cement—not concrete—SRMs that help manufacturers ensure their products meet certain quality standards and help buyers know they’re getting what they paid for.

    5
    NIST researchers in CAVE 3D Visualization lab exploring the movement of concrete particles. Credit: copyright Earl Zubkoff

    Standards of excellence

    To tell the story of SRMs is to tell the story of industry in America—its breakthroughs and its setbacks. From the turn of the 20th century onward, NIST stood with American makers as they erected skyscrapers, laid railways and took to the skies in airplanes. NIST helped manufacturers overcome technical challenges they faced in bringing innovative technology to the American people.

    In 1905, NIST—then known as the National Bureau of Standards—began preparing and distributing the first SRMs, standardized samples of iron, which manufacturers used as a check on their lab analyses. From those early standard samples, the program grew.

    Today, NIST still sells versions of these original SRMs, but it has come a long way. The diverse array of SRMs currently available reflect the complexity and technological advancement of a 21st-century society—and the new challenges it faces.

    NIST constantly works to improve its existing SRMs to adapt to changing needs—such as the arsenic levels added to the rice flour SRM, or the blueberry SRM, to which NIST is in the process of adding measurements for anthocyanins, a type of flavonoid, or pigment, in the blueberries that contributes to its antioxidant properties. And, NIST is always looking for opportunities to create new SRMs to drive innovation in emerging markets, like the monoclonal antibody SRM for biopharmaceutical manufacturers.

    “Good science is our carrot,” Choquette says.

    Speaking of carrots, we’ve got an SRM for that.

    To learn more about NIST’s Standard Reference Materials, visit http://www.nist.gov.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    NIST Campus, Gaitherberg, MD, USA

    NIST Mission, Vision, Core Competencies, and Core Values

    NIST’s mission

    To promote U.S. innovation and industrial competitiveness by advancing measurement science, standards, and technology in ways that enhance economic security and improve our quality of life.
    NIST’s vision

    NIST will be the world’s leader in creating critical measurement solutions and promoting equitable standards. Our efforts stimulate innovation, foster industrial competitiveness, and improve the quality of life.
    NIST’s core competencies

    Measurement science
    Rigorous traceability
    Development and use of standards

    NIST’s core values

    NIST is an organization with strong values, reflected both in our history and our current work. NIST leadership and staff will uphold these values to ensure a high performing environment that is safe and respectful of all.

    Perseverance: We take the long view, planning the future with scientific knowledge and imagination to ensure continued impact and relevance for our stakeholders.
    Integrity: We are ethical, honest, independent, and provide an objective perspective.
    Inclusivity: We work collaboratively to harness the diversity of people and ideas, both inside and outside of NIST, to attain the best solutions to multidisciplinary challenges.
    Excellence: We apply rigor and critical thinking to achieve world-class results and continuous improvement in everything we do.

     
  • richardmitnick 2:43 pm on June 10, 2017 Permalink | Reply
    Tags: , New NIST technique for controlling the quantum properties of individual charged molecules, NIST, NIST Physicists Find a Way to Control Charged Molecules – with Quantum Logic, , Quantum states, The method could also be used to answer deep physics questions such as whether fundamental “constants” of nature change over time   

    From NIST: “NIST Physicists Find a Way to Control Charged Molecules – with Quantum Logic” 

    NIST

    May 10, 2017 [Where was this hiding?]

    Laura Ost
    laura.ost@nist.gov
    (303) 497-4880

    National Institute of Standards and Technology (NIST) physicists have solved the seemingly intractable puzzle of how to control the quantum properties of individual charged molecules, or molecular ions. The key: use the same kind of “quantum logic” operations designed for carrying out computations in future quantum computers.

    The new technique achieves an elusive goal, controlling molecules as effectively as laser cooling and other techniques can control atoms. Quantum control of atoms has revolutionized atomic physics, leading to applications such as atomic clocks. But laser cooling and control of molecules is extremely challenging because they are much more complex than atoms.

    The NIST technique still uses a laser, but only to gently probe the molecule; its quantum state is detected indirectly. This type of control of molecular ions—several atoms bound together and carrying an electrical charge—could lead to more sophisticated architectures for quantum information processing, amplify signals in basic physics research such as measuring the “roundness” of the electron’s shape, and boost control of chemical reactions.

    The research is described in the May 11 issue of Nature and was performed by the NIST Boulder group that demonstrated the first laser cooling of atomic ions in 1978.

    “We developed methods that are applicable to many types of molecules,” NIST physicist James Chin-wen Chou said. “Whatever trick you can play with atomic ions is now within reach with molecular ions. Now the molecule will ‘listen’ to you—asking, in effect, ‘What do you want me to do?’”

    1
    Credit: N. Hanacek/NIST

    “This is comparable to when scientists could first laser cool and trap atoms, opening the floodgates to applications in precision metrology and information processing. It’s our dream to achieve all these things with molecules,” Chou added.

    Compared to atoms, molecules are more difficult to control because they have more complex structures involving many electronic energy levels, vibrations and rotations. Molecules can consist of many different numbers and combinations of atoms and be as large as DNA strands at more than a meter long.

    The NIST method finds the quantum state (electronic, vibrational and rotational) of the molecular ion by transferring the information to an atomic ion, which can be laser cooled and controlled with previously known techniques. Borrowing ideas from NIST’s quantum logic clock, the researchers attempt to manipulate the molecular ion and, if successful, set off a synchronized motion in the pair of ions. The manipulation is chosen such that it can only trigger the motion if the molecule is in a certain state. The “yes” or “no” answer is signaled by the atomic ion. The technique is very gentle, indicating the molecule’s quantum states without destroying them.

    “The molecule only jiggles if it is in the right state. The atom feels that jiggle and can transfer the jiggle into a light signal we can pick up,” senior author Dietrich Leibfried said. “This is like Braille, which allows people to feel what is written instead of seeing it. We feel the state of the molecule instead of seeing it and the atomic ion is our microscopic finger that allows us to do that.”


    This animation shows the basics steps in a new NIST technique for controlling the quantum properties of individual charged molecules, or molecular ions. The method borrows a “quantum logic” approach from an experimental NIST atomic clock. The new method can be used to control many types of molecules and has potential applications in quantum information processing and other fields.

    “Moreover, the method should be applicable to a large group of molecules without changing the setup. This is part of NIST’s basic mission, to develop precision measurement tools that maybe other people can use in their work,” Leibfried added.

    To perform the experiment, NIST researchers scavenged old but still functional equipment, including an ion trap used in a 2004 quantum teleportation experiment. They also borrowed laser light from an ongoing quantum logic clock experiment in the same lab.

    The researchers trapped two calcium ions just a few millionths of a meter apart in a high-vacuum chamber at room temperature. Hydrogen gas was leaked into the vacuum chamber until one calcium ion reacted to form a calcium hydride (CaH+) molecular ion made of one calcium ion and one hydrogen atom bonded together.

    Like a pair of pendulums that are coupled by a spring, the two ions can develop a shared motion because of their physical proximity and the repulsive interaction of their electrical charges. The researchers used a laser to cool the atomic ion, thereby also cooling the molecule to the lowest-energy state. At room temperature, the molecular ion is also in its lowest electronic and vibrational state but remains in a mixture of rotational states.

    The researchers then applied pulses of infrared laser light—tuned to prevent changes to the ions’ electronic or vibrational states—to drive a unique transition between two of more than 100 possible rotational states of the molecule. If this transition occurred, one quantum of energy was added to the two ions’ shared motion. Researchers then applied an additional laser pulse to convert the change in the shared motion into a change in the atomic ion’s internal energy level. The atomic ion then started scattering light, signaling that the molecular ion’s state had changed and it was in the desired target state.

    Subsequently, researchers can then transfer angular momentum from the light emitted and absorbed during laser-induced transitions to, for example, orient the molecule’s rotational state in a desired direction.

    The new techniques have a wide range of possible applications. Other NIST scientists at JILA previously used lasers to manipulate clouds of specific charged molecules in certain ways, but the new NIST technique could be used to control many different types of larger molecular ions in more ways, Chou said.

    Molecular ions offer more options than atomic ions for storing and converting quantum information, Chou said. For example, they could offer more versatility for distributing quantum information to different types of hardware such as superconducting components.

    The method could also be used to answer deep physics questions such as whether fundamental “constants” of nature change over time. The calcium hydride molecular ion has been identified as one candidate for answering such questions. In addition, for measurements of the electron’s electric dipole moment (a quantity indicating the roundness of the particles charge distribution), the ability to precisely control all aspects of hundreds of ions at the same time would boost the strength of the signal that scientists want to measure, Chou said.

    The work was supported by the U.S. Army Research Office.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    NIST Campus, Gaitherberg, MD, USA

    NIST Mission, Vision, Core Competencies, and Core Values

    NIST’s mission

    To promote U.S. innovation and industrial competitiveness by advancing measurement science, standards, and technology in ways that enhance economic security and improve our quality of life.
    NIST’s vision

    NIST will be the world’s leader in creating critical measurement solutions and promoting equitable standards. Our efforts stimulate innovation, foster industrial competitiveness, and improve the quality of life.
    NIST’s core competencies

    Measurement science
    Rigorous traceability
    Development and use of standards

    NIST’s core values

    NIST is an organization with strong values, reflected both in our history and our current work. NIST leadership and staff will uphold these values to ensure a high performing environment that is safe and respectful of all.

    Perseverance: We take the long view, planning the future with scientific knowledge and imagination to ensure continued impact and relevance for our stakeholders.
    Integrity: We are ethical, honest, independent, and provide an objective perspective.
    Inclusivity: We work collaboratively to harness the diversity of people and ideas, both inside and outside of NIST, to attain the best solutions to multidisciplinary challenges.
    Excellence: We apply rigor and critical thinking to achieve world-class results and continuous improvement in everything we do.

     
  • richardmitnick 3:02 pm on June 9, 2017 Permalink | Reply
    Tags: , Atomic force microscope (AFM), , Cathodoluminescence, dt-NSOM technique, , NIST, Novel Techniques Examine Solar Cells with Nanoscale Precision, Photoluminescence, Photothermal induced resonance (PTIR)   

    From NIST: “Novel Techniques Examine Solar Cells with Nanoscale Precision” 

    NIST

    June 09, 2017

    1
    Schematic of cadmium telluride examined by the photothermal induced resonance technique.
    Credit: Yoon et al./NIST

    Using two novel techniques, researchers at the National Institute of Standards and Technology (NIST) have for the first time examined, with nanometer-scale precision, the variations in chemical composition and defects of widely used solar cells. The new techniques, which investigated a common type of solar cell made of the semiconductor material cadmium telluride, promise to aid scientists in better understanding the microscopic structure of solar cells and may ultimately suggest ways to boost the efficiency at which they convert sunlight to electricity.

    Even though standard methods to characterize solar cells have long proven useful in guiding their fabrication and design, these diagnostic tools “give us only a limited understanding of why the devices operate at sub-optimal efficiency,” said NIST physicist Nikolai Zhitenev. For instance, although a method known as electron-beam induced current, which analyzes samples using the beam of an electron microscope, provides data on nanoscale variations in solar cell efficiency, it gives little information on the underlying crystal defects and impurities that degrade efficiency. Two other methods, photoluminescence and cathodoluminescence, which induce light emission from the samples, provide only insufficient or indirect information on the mechanisms of efficiency losses.

    To close that knowledge gap, “we’ve now developed new techniques to examine the microstructure of solar cells and demonstrated that we can visualize defects through their optical signature,” said lead author Yohan Yoon of NIST and the University of Maryland in College Park. He and his colleagues at NIST, the University of Maryland and the University of Utah described their work in a recent Nanoscale paper .

    In their study, the scientists used two complementary methods that rely on an atomic force microscope (AFM). Photothermal induced resonance (PTIR) provides information on the solar cell’s composition and defects at the nanometer-size scale by measuring how much light the sample absorbs over a broad range of wavelengths, from visible light to the mid-infrared. The other method, known as direct-transmission near-field scanning optical microscopy (dt-NSOM), creates detailed nanoscale images that capture variations in the composition of the solar cells and defects in their structure by recording how much light is transmitted at specific sites within the cell. The method produces sharper images than PTIR.

    The setup for PTIR, assembled by NIST researcher Andrea Centrone, resembles a finely tuned version of a Rube Goldberg contraption. First, light pulses from a laser illuminate a sample of cadmium telluride. When the sample absorbs the laser light, it heats up and expands. The expansion nudges the sharp tip of an AFM that is in contact with the sample. The tip converts the heat-induced expansion into mechanical motion, causing the cantilever on which it is mounted to vibrate. Finally, the vibration is detected by bouncing light from another laser off the cantilever into the AFM detector.

    2
    Topographic image (a) of a thin slice of a cadmium-telluride sample and images (b-f) of same slice taken with the direct-transmission near-field scanning optical microscopy technique.
    Credit: Yoon et al./NIST

    Because the extent of the cantilever’s vibrations is proportional to the energy absorbed by the cadmium telluride sample, PTIR measurements provide key information about the material. For instance, when the tip is held at one location on the sample but the wavelength of pulsed laser light is varied, PTIR generates information on the spectra of radiation that is absorbed at different points along the sample, with nanoscale resolution. When the AFM tip moves over the sample but the laser’s wavelength remains fixed, PTIR yields an absorption map of the material that reveals variations in chemical composition from one part of the sample to the other. Notably, the small size of the probe tip provides absorption information with a spatial resolution smaller than the laser wavelength used in the experiments.

    In the dt-NSOM technique, light from the sharp tip of an AFM probe illuminates a small part of the sample. A photodetector in contact with the sample measures the amount of light transmitted through the material as the probe scans over the sample.

    Critical to the success of the two techniques, notes Zhitenev, was not only access to an AFM, but to other advanced equipment available at NIST’s Center for Nanoscale Science and Technology (CNST), where the experiments were performed. This includes a focused ion beam that could cut slices of the cadmium telluride material a mere 350 nanometers (350 billionths of a meter) in thickness.

    “Without the ability to obtain such ultrathin slices, it would not have been possible to take full advantage of the high-resolution techniques and reveal fine details of the solar cell material,” he said. The wavelengths of light used to probe the semiconductor would normally penetrate to a depth of several millionths of a meter. By cutting slices thinner than that depth, the thickness of the slices determines the effective spatial resolution of the analysis, explained Zhitenev.

    The experiments showed that defects in the crystal arrangement of the material are related to impurities in the chemical composition, propagated along and from the boundaries between adjoining crystal grains. The team also demonstrated that techniques can measure the spatial variation of so-called deep defects in cadmium telluride samples. These defects, which cause electrons and holes (positively charged particles) in cadmium telluride and other semiconductors to recombine instead of generating electricity, are one of the key reasons that solar cells do not perform as well as theoretical models.

    Although the new measurements are presented as a proof of concept in studying cadmium telluride, a well-characterized material, the findings “are of broad applicability and will aid solar cell research, leading to a better understanding of a variety of photovoltaic materials, and consequently, engineer them for greater efficiency,” the researchers concluded.

    “Without the ability to obtain such ultrathin slices, it would not have been possible to take full advantage of the high-resolution techniques and reveal fine details of the solar cell material,” he said. The wavelengths of light used to probe the semiconductor would normally penetrate to a depth of several millionths of a meter. By cutting slices thinner than that depth, the thickness of the slices determines the effective spatial resolution of the analysis, explained Zhitenev.

    The experiments showed that defects in the crystal arrangement of the material are related to impurities in the chemical composition, propagated along and from the boundaries between adjoining crystal grains. The team also demonstrated that techniques can measure the spatial variation of so-called deep defects in cadmium telluride samples. These defects, which cause electrons and holes (positively charged particles) in cadmium telluride and other semiconductors to recombine instead of generating electricity, are one of the key reasons that solar cells do not perform as well as theoretical models.

    Although the new measurements are presented as a proof of concept in studying cadmium telluride, a well-characterized material, the findings “are of broad applicability and will aid solar cell research, leading to a better understanding of a variety of photovoltaic materials, and consequently, engineer them for greater efficiency,” the researchers concluded.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    NIST Campus, Gaitherberg, MD, USA

    NIST Mission, Vision, Core Competencies, and Core Values

    NIST’s mission

    To promote U.S. innovation and industrial competitiveness by advancing measurement science, standards, and technology in ways that enhance economic security and improve our quality of life.
    NIST’s vision

    NIST will be the world’s leader in creating critical measurement solutions and promoting equitable standards. Our efforts stimulate innovation, foster industrial competitiveness, and improve the quality of life.
    NIST’s core competencies

    Measurement science
    Rigorous traceability
    Development and use of standards

    NIST’s core values

    NIST is an organization with strong values, reflected both in our history and our current work. NIST leadership and staff will uphold these values to ensure a high performing environment that is safe and respectful of all.

    Perseverance: We take the long view, planning the future with scientific knowledge and imagination to ensure continued impact and relevance for our stakeholders.
    Integrity: We are ethical, honest, independent, and provide an objective perspective.
    Inclusivity: We work collaboratively to harness the diversity of people and ideas, both inside and outside of NIST, to attain the best solutions to multidisciplinary challenges.
    Excellence: We apply rigor and critical thinking to achieve world-class results and continuous improvement in everything we do.

     
  • richardmitnick 2:28 pm on May 30, 2017 Permalink | Reply
    Tags: , , NIST, Perovskites could become the next superstars of solar cells   

    From NIST: “Unexpected Property May Raise Material’s Prospects as Solar Cell” 

    NIST

    May 22, 2017

    Ben Stein
    benjamin.stein@nist.gov
    (301) 975-2763

    NIST, collaborators find first compelling evidence of new property known as “ferroelasticity” in perovskites.

    1
    Schematic shows a perovskite sample (black) examined by the photothermal induced resonance technique. When the sample absorbs pulses of light (depicted as disks in purple cones), the sample expands rapidly, causing the cantilever of an atomic force microscope (AFM) to vibrate like a struck tuning fork. The cantilever’s motion, which is detected by reflecting the AFM laser light (red) off the AFM detector, provides a sensitive measure of the amount of light absorbed. Credit: NIST

    Crystalline materials known as perovskites could become the next superstars of solar cells. Over the past few years, researchers have demonstrated that a special class of perovskites—those consisting of a hybrid of organic and inorganic components—convert sunlight into electricity with an efficiency above 20 percent and are easier to fabricate and more impervious to defects than the standard solar cell made of crystalline silicon. As fabricated today, however, these organic/inorganic perovskites (OIPs) deteriorate well before the typical 30-year lifetime for silicon cells, which prevents their widespread use in harnessing solar power.

    Now a team led by Andrea Centrone at the National Institute of Standards and Technology (NIST) and Jinsong Huang and Alexei Gruverman of the University of Nebraska has found the first solid evidence for a property of OIPs that may provide a new way to improve their long-term stability as solar cells.

    2
    Image recorded by an atomic force microscope reveals the topography of a polycrystalline sample of the perovskite, including the boundaries between crystals. Credit: NIST

    3

    Image taken with the photothermal induced resonance technique shows the newly discovered ferroelastic domains (striations) within most crystals. Scale shows the PTIR signal intensity, a measure of the infrared light absorbed by the sample. Credit: NIST

    The unexpected feature that the team found is known as ferroelasticity—a spontaneous rearrangement of the internal structure of OIPs in which each crystal subdivides into a series of tiny regions, or domains, that have the same atomic arrangement but which are oriented in different directions. This rearrangement creates a spontaneous strain in each domain that exists even in the absence of any external stress (force).

    The researchers recently described their work in Science Advances.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    NIST Campus, Gaitherberg, MD, USA

    NIST Mission, Vision, Core Competencies, and Core Values

    NIST’s mission

    To promote U.S. innovation and industrial competitiveness by advancing measurement science, standards, and technology in ways that enhance economic security and improve our quality of life.
    NIST’s vision

    NIST will be the world’s leader in creating critical measurement solutions and promoting equitable standards. Our efforts stimulate innovation, foster industrial competitiveness, and improve the quality of life.
    NIST’s core competencies

    Measurement science
    Rigorous traceability
    Development and use of standards

    NIST’s core values

    NIST is an organization with strong values, reflected both in our history and our current work. NIST leadership and staff will uphold these values to ensure a high performing environment that is safe and respectful of all.

    Perseverance: We take the long view, planning the future with scientific knowledge and imagination to ensure continued impact and relevance for our stakeholders.
    Integrity: We are ethical, honest, independent, and provide an objective perspective.
    Inclusivity: We work collaboratively to harness the diversity of people and ideas, both inside and outside of NIST, to attain the best solutions to multidisciplinary challenges.
    Excellence: We apply rigor and critical thinking to achieve world-class results and continuous improvement in everything we do.

     
  • richardmitnick 8:36 pm on May 26, 2017 Permalink | Reply
    Tags: , ‘Spintronic’ Computing, NIST   

    From NIST: “NIST Invents Fundamental Component for ‘Spintronic’ Computing” 

    NIST

    April 26, 2017
    Media Contact
    Ben Stein
    benjamin.stein@nist.gov
    (301) 975-2763

    Technical Contact
    Curt A. Richter
    curt.richter@nist.gov
    (301) 975-2082

    NIST has been granted a patent for technology that may hasten the advent of a long-awaited new generation of high-performance, low-energy computers.

    1

    Conventional microelectronic devices, for the most part, work by manipulating and storing electrical charges in semiconductor transistors and capacitors. Doing so requires a lot of energy and generates a lot of heat, especially as process engineers keep finding ways to pack more and smaller features into integrated circuits. Power consumption has become one of the principal obstacles to much higher performance.

    One highly promising alternative approach, called “spintronics,” utilizes the quantum spin* of the electron to hold information in addition to the charge. The two different spin orientations (typically designated “up” and “down”) are analogous to positive and negative electrical charges in conventional electronics. Because changing an electron’s spin requires very little energy and can happen very fast, spintronics offers the possibility of significant energy reduction.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    NIST Campus, Gaitherberg, MD, USA

    NIST Mission, Vision, Core Competencies, and Core Values

    NIST’s mission

    To promote U.S. innovation and industrial competitiveness by advancing measurement science, standards, and technology in ways that enhance economic security and improve our quality of life.
    NIST’s vision

    NIST will be the world’s leader in creating critical measurement solutions and promoting equitable standards. Our efforts stimulate innovation, foster industrial competitiveness, and improve the quality of life.
    NIST’s core competencies

    Measurement science
    Rigorous traceability
    Development and use of standards

    NIST’s core values

    NIST is an organization with strong values, reflected both in our history and our current work. NIST leadership and staff will uphold these values to ensure a high performing environment that is safe and respectful of all.

    Perseverance: We take the long view, planning the future with scientific knowledge and imagination to ensure continued impact and relevance for our stakeholders.
    Integrity: We are ethical, honest, independent, and provide an objective perspective.
    Inclusivity: We work collaboratively to harness the diversity of people and ideas, both inside and outside of NIST, to attain the best solutions to multidisciplinary challenges.
    Excellence: We apply rigor and critical thinking to achieve world-class results and continuous improvement in everything we do.

     
  • richardmitnick 10:27 am on May 25, 2017 Permalink | Reply
    Tags: , , Masao Kuriyama, NIST,   

    From NIST: Masao Kuriyama 

    NIST

    1

    Masao Kuriyama developed an award-winning X-ray magnifier in 1979 that improved the resolution of industrial X-ray imaging by a factor of 25. X-ray images of industrial equipment often provided evidence of cracks, voids, or other imperfections. Kuriyama’s work helped manufacturers make better parts faster.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    NIST Campus, Gaitherberg, MD, USA

    NIST Mission, Vision, Core Competencies, and Core Values

    NIST’s mission

    To promote U.S. innovation and industrial competitiveness by advancing measurement science, standards, and technology in ways that enhance economic security and improve our quality of life.
    NIST’s vision

    NIST will be the world’s leader in creating critical measurement solutions and promoting equitable standards. Our efforts stimulate innovation, foster industrial competitiveness, and improve the quality of life.
    NIST’s core competencies

    Measurement science
    Rigorous traceability
    Development and use of standards

    NIST’s core values

    NIST is an organization with strong values, reflected both in our history and our current work. NIST leadership and staff will uphold these values to ensure a high performing environment that is safe and respectful of all.

    Perseverance: We take the long view, planning the future with scientific knowledge and imagination to ensure continued impact and relevance for our stakeholders.
    Integrity: We are ethical, honest, independent, and provide an objective perspective.
    Inclusivity: We work collaboratively to harness the diversity of people and ideas, both inside and outside of NIST, to attain the best solutions to multidisciplinary challenges.
    Excellence: We apply rigor and critical thinking to achieve world-class results and continuous improvement in everything we do.

     
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