This Just In! (Archives)
Safety Measures
Lisa Karam, Chief of the Radiation and Biomolecular Physics Division, gave a talk on the occasion of World Metrology Day (May 21, 2012). Karam’s talk, part of a NIST colloquium, was titled “Radiation Metrology for Safety in Health Care,” in keeping with the theme of this year’s celebration, "Metrology for Safety." She covered topics including history, radiation measurements for diagnostic (imaging) and therapeutic (radiation therapy) applications, and the use of radiation to assure safety of medical devices (sterilization).
One Show Only
On June 5-6, people around the world watched the last Transit of Venus to be seen until the year 2117. A few hundred of them saw it on June 5 at Montgomery Blair High School in Silver Spring, MD, where postdoc Stephen Redman (shown at right) of the Atomic Spectroscopy Group in PML’s Quantum Measurement Division gave an illustrated talk followed by a live video feed of the transit. On the previous day, Redman was interviewed by Kojo Nnamdi of National Public Radio’s Kojo Nnamdi Show.
Workshops and Work Products
Last November, the Radiation and Biomolecular Physics Division hosted a technical workshop related to optical medical imaging in November 2011. Now the proceedings from that workshop have been published in a special issue of the Journal of Biomedical Optics Express. Jeeseong Hwang of the Biophysics Group, who organized the workshop, served as guest editor for the special issue.
On June 3, a day-long workshop titled “Frontiers of Characterization and Metrology for Micro- and Nanosystems” – organized by a group of three NIST researchers: Michael Gaitan of PML’s Semiconductor and Dimensional Metrology Division; Robert Cook of the Material Measurement Laboratory; and Jason Gorman of the Engineering Laboratory – was held in conjunction with the Solid-State Sensors, Actuators, and Microsystems Workshop in Hilton Head, S.C.
Heavy Stuff
A semi-popular article by PML’s Charles Clark and Joseph Reader about the discovery of deuterium, the stable heavy isotope of hydrogen, was selected as a feature article for the May 2012 issue of Optics and Photonics News, the monthly magazine of the Optical Society of America.
The article highlights the role of NIST (then NBS) low-temperature expert Ferdinand Brickwedde in the 1931 discovery. He was recruited to the hunt for deuteriumby Harold Urey of Columbia University, who wanted Brickwedde to prepare samples of liquid hydrogen. By photographing spectra of the samples on a high-resolution spectrograph, Urey found an extra line in the spectrum at the wavelength expected for this long-sought isotope. The discovery earned Urey the 1934 Nobel Prize in Chemistry.
Brickwedde, meanwhile, continued a distinguished career. While still at NBS, he produced the liquid deuterium fuel for the first hydrogen bomb explosion in 1952. Subsequently, Brickwedde was appointed Dean of the College of Chemistry and Physics at the Pennsylvania State University. He died in 1989 at the age of 86.
The photo at left shows Brickwedde with his wife, physicist Marion Langhorne Howard Brickwedde (1909-1997). Between them is the apparatus for making heavy water.
Busy Meeting But No Pressure
NIST will host the DC Regional Meeting of the American Vacuum Society’s Mid-Atlantic Chapter on Thursday, June 14, 2012 from 9 a.m. to 3 p.m. For details or questions, contact Jay Hendricks of the Sensor Science Division.
Security Pays Off
PML's Radiation and Biomolecular Physics Division played a large role in the recently published report from NIST's Standards Coordination Office. Titled A Case Study -- The Economic Benefits of NIST’s Role in Security Standards Development: X-Ray Standards for Bulk-Explosives Detection, the report shows how "standards, and their underlying measurement technology, create economic value in a myriad of ways."
Si Single-Electron Devices Move to the Fab Fore
In partial culmination of several years of effort, a PML team has succeeded in making functioning single-electron devices using Si and SiO2 materials in the NIST nanofabrication facility. (See image at right.)
Making the devices, simply described as nano MOSFETs, required an extraordinarily complicated sequence of multiple layers of gates. The project exploited several important capabilities of the nanofabrication facility, including nanolithography, dry etching, and the ability to deposit and pattern low-defect density materials.
The Si-based devices will be used to implement single-electron based devices for quantum information processing, and advance the prospect of realizing quantum information devices that are directly compatible with current Si-based electronics. At the same time, the devices promise significant advances for single-electron metrology. They exhibit attractive characteristics, including good homogeneity of MOSFET threshold voltage, robustness with respect to electrical damage, and superior Coulomb blockade effects.
The PML team includes Michael "Stew" Stewart Jr, who has recently given talks on the results in Australia, Panu Koppinen, who is preparing a paper for publication, and project leader Neil Zimmerman. The team has benefited substantially from assistance by staff at the Center for Nanoscale Science and Technology (CNST), including Jerry Bowser, Lei Chen, and Vince Luciani.
Patently Successful
In February, Michael Moldover and Gregory Strouse of PML’s Sensor Science Division, and Dean Ripple of the Biochemical Science Division in the Material Measurement Laboratory, were awarded a patent (US 8,123,300 B2) for a “dielectric resonator thermometer and a method of using the same.”
Now the researchers are beginning a long-term development effort, and PML has hired Zeeshan Ahmed, an analytical spectroscopist currently serving as an NRC Postdoctoral Fellow, to work on the project.
Washington Academy Honors Olthoff, Hwang
PML Deputy Director James Olthoff (left photo) has received the 2012 Award for Physical Sciences from the Washington Academy of Sciences “for broad contributions to metrology through advancing plasma physics and through management of the NIST Measurement Services Program, the most robust, rigorous and diverse in the world.” This spans his initial research at NBS in developing diagnostics for electrical discharges, including those of interest to the semiconductor industry, to his leadership in coordinating measurement services.
Jeeseong Hwang (Radiation and Biomolecular Physics Division, right photo) received the Academy’s 2012 Award for Biological Sciences “in recognition of contributions to research and service in the field of biomedical optics, specifically in the advancement and validation of advanced microscopic techniques and tissue phantoms for translational and clinical applications.” At NIST, he has advanced novel microscopies for application in the biological sciences, including near-field microscopy and the application of quantum dots for biomedical imaging. He is currently working to improve measurement methods and traceability in optical medical imaging, to make it a more quantitative science.
T&H Gets Hot
Michal Chojnacky of the Temperature and Humidity Group from Sensor Science Division did two talks for the first all-online National Immunization Conference on March 26-28: “NIST Case Study of Dual-Zone Unit for Simultaneous Refrigerated and Frozen Vaccine Storage,” and “Data-Logger Thermometers for Continuous Temperature Monitoring of Refrigerated Vaccines.” More than 1,000 people took part from their computers. Dawn Cross gave a presentation from her desk in PML, via computer and phone, to the LTIG EPA Conference on 23 April. (LTIG stands for Laboratory and Technical Information Group, made up of the EPA regional laboratories.) Cross had more than 50 people in the conference room and over 60 people online.
Experimentoring -- The Sequel
Jennifer Gagner, a 10th-grade student at Winston Churchill High School in Montgomery County, MD who was mentored in PML’s Quantum Optics Group, recently won a second prize in Computer Science and Mathematics at ScienceMONTGOMERY. Now her work at NIST has garnered another honor. The Optical Society of America and the IEEE Photonics Society have chosen her science-fair project, "Modeling Photodiode Detector Non-Uniformity," to receive an Outstanding Achievement in Optics Award at the Annual Student Recognition Awards Banquet on May 15.
Cosmic Perspective
Researchers from PML’s Quantum Electronics and Photonics Division are part of a large international collaboration that recently announced the first detection of galaxy-cluster motion based on the kinetic Sunyaev-Zel’dovich effect predicted in 1972 – subtle distortions in the cosmic microwave background due to motion of high-energy electrons. The authors, who include Kent Irwin, Joseph Fowler, Michael Niemack, and Daniel Swetz of the Quantum Devices Group, conclude that the observations represent “the first measurement of the cosmic velocity field made directly with respect to the rest frame of the universe.”
The microwave data were taken with the camera at the Atacama Cosmology Telescope in Chile, which relies on superconducting sensors based on a NIST design and superconducting amplifiers and electronics made at NIST.
Better Yet
Optics Letters has released its list of the top 10 most-cited papers of the past five years. One of them is “Compact, thermal-noise-limited optical cavity for diode laser stabilization at 1 X 10−15” by members of a group at JILA headed by Jun Ye of PML’s Quantum Physics Division. That 2007 paper set a very high standard for laser stability. But now Ye, Michael Martin, and Lisheng Chen of JILA, with collaborators at Germany’s Physikalisch-Technische Bundesanstalt, have raised the bar by an order of magnitude, with a monolithic silicon crystal cavity giving a laser stability of 1 x 10-16 at 1 second. The findings are set to be published soon.
Highly Charged Findings
The paper “EUV spectral lines of highly-charged Hf, Ta and Au ions observed with an electron beam ion trap” by Ilija Dragani´c, Yuri Ralchenko, Joseph Reader, J.D. Gillaspy, Joseph Tan, Joshua Pomeroy, Samuel Brewer and Dmitry Osin has been named a 2011 Highlight of the Journal of Physics B: Atomic, Molecular and Optical Physics. This distinction is given to a few papers of “outstanding and excellent” quality published by the journal in 2011.
The article reports on accurate measurements and identifications of more than a 100 new emission wavelengths of highly-ionized atoms of Hf, Ta and Au in the extreme ultraviolet (EUV) wavelength range. The measurements were performed on the NIST Electron Beam Ion Trap (EBIT) and are used for the development of fusion energy devices such as the internationally sponsored ITER device in Cadarache, France.
Reader and ITER
PML physicist and NIST Fellow Joseph Reader (shown at left) has been selected by the International Atomic Energy Agency (IAEA) to represent the U.S. on the International Fusion Research Council (IFRC) Subcommittee on Atomic and Molecular Data for Fusion.
The Subcommittee meets regularly to advise the IAEA on ways to ensure the availability of adequate atomic and molecular data for the development of fusion energy. The largest international fusion energy program is the development of ITER, to be built in Cadarache, France.
Keynote in 3D
Andras E. Vladar of PML’s Semiconductor and Dimensional Metrology Division (shown at right) delivered the keynote presentation titled “Can we get 3D CD Metrology Right?” at the Metrology, Inspection, and Process Control for Microlithography Conference at the recent SPIE Advanced Lithography 2012 meeting in San Jose, CA. This presentation pointed out that, for semiconductor manufacturing, optical lithography is printing photoresist features that are significantly smaller than the wavelength of the light used and therefore requires the implementation of optical proximity correction methods.
The presentation proposed the implementation of new NIST-developed methods for 3D metrology that extend to below 10 nanometer-sized structures. Vladar covered key aspects of 3D integrated circuit dimensional metrology, offered physics-based measurement methods, and advocated widespread use of scientific metrology solutions.
VCI FYI
John Villarrubia of PML’s Semiconductor and Dimensional Metrology Division recently completed a project with Intel on "VCI Simulation with Semiconductor Device Models." ("VCI" is voltage contrast imaging.) Electron beam (e-beam) inspection tools are used to search for electrical defects in metal-filled contacts in integrated circuits. The contacts electrically connect one layer (e.g., the transistors) with the layer above it through an intervening insulator. Under e-beam exposure, unsuccessful (open circuit) contacts or contacts with too much resistance charge to different potentials than successful ones. Most electrons emitted from the surface are secondary electrons, with kinetic energies below 10 eV. Potential differences of only a few volts can strongly affect the escape probability of these low-energy electrons—hence "voltage contrast imaging." To accommodate this imaging mode, capabilities were added to PML’s JMONSEL (Java Monte Carlo simulator for Secondary Electrons) software. Applications of JMONSEL are expected in the design and interpretation of e-beam tool dimensional calibrations, semiconductor industry critical dimension measurements for process control, and defect inspection.
Science Fighting Crime
Following an agency-wide intramural funding competition for proposals directed “toward the identification and/or assessment of the feasibility of using new scientific discoveries (developed at NIST or elsewhere) for criminal justice applications,” two PML groups have been selected for support. One will work on Nuclear Forensic Reference Materials (RM) for Attribution of Urban Nuclear Terrorism, and includes researchers Ken Inn, Jacqueline Mann, Jeffrey Leggitt, Joanne Buscaglia, Simone Jerome, and John Malloy. The other group, whose members include J. Song, J. Yen, T.V. Vorburger, and W. Chu, will begin to establish a “National Ballistics Evidence Search Engine (NBESE) based on 3D topography measurements on correlation cells."
Experimentoring
Jennifer Gagner, a 10th-grade student at Winston Churchill High School in Montgomery County, MD who was mentored in PML’s Quantum Measurement Division, won a second prize in Computer Science and Mathematics at ScienceMONTGOMERY, the Montgomery County Maryland science fair. She won $100 and a certificate for her project about modeling photo-diode detector non-uniformities.
Gagner was mentored on her project by Boris Glebov, a guest researcher in the Quantum Optics Group. She also won a certificate and medal in the community awards category, in ScienceMONTGOMERY Awards for Projects in the Senior Division Demonstrating Excellence in Scientific Exposition.
Up and Coming
Add to the list of PML’s distinguished young associates Ari Misha Dyckovsky, 18, of Leesburg, VA, a high-school student at the Loudoun County Academy of Science. While working with physicist Steve Olmschenk of the Quantum Measurement Division, he produced a theoretical/computational paper (submitted for publication) about the possibility of using two-photon interference protocols to entangle quantum memories. The results earned him a spot as one of the 40 Intel Science Talent Search finalists.
“Ari has been working with me since January of 2010,” Olmschenk says. “We started with me presenting a ‘crash course’ in quantum physics, and then moved on to work on the photon interference research project. He’s now working with (PML physicist) Trey Porto, (graduate student) Roger Brown, and me in Trey's optical lattice lab, learning the art of being an experimentalist.”
Dyckovsky, a recreational tennis player and a classical guitarist, has participated in several previous science contests, including: the International Space Olympics in 2010 (1st place); the National Junior Science and Humanities Symposia 2011 (2nd place); and the Siemens Competition 2011 (semi-finalist).
New Frontiers in Space
In February, 2012, NIST took possession from the contractors of the building that will house the long-awaited, state-of-the-art, precision measurement facility on the Boulder campus. The structure, part of which is shown here, will be dedicated later this year. The laboratory and fabrication capabilities will help NIST better meet the needs of U.S. industry and science in key national priority areas such as nanotechnology, new energy sources, enhanced telecommunications, and radically new information technology such as quantum computers. PML will be the largest single user of the 58,000 square foot facility, an extension to the existing Building 1 which dates from 1954.
PML Fields Unit on Units
On February 19, at the 2012 annual meeting of the American Association for the Advancement of Science in Vancouver, NIST co-organized a symposium with the National Research Council of Canada titled “Updating the International System of Units: The Foundation for Science and Technology.” Seen at the scene, from left: Stephan Schlamminger (PML, Quantum Measurement Division), Vijay Srinivasan (Metrology Division), Charles Clark (PML, Quantum Measurement Division), invited speaker Georgia Harris (PML Lab Office), PML Deputy Director and symposium co-organizer Jim Olthoff, and David Newell (PML Quantum Measurement Division).
PML Work Highlighted in Journal of Physics B
A paper by a team from the Quantum Measurement Division is the top item in the Journal of Physics B's annual highlights compendium of work published in 2011 as selected by the journal's editorial and advisory boards. The paper is "EUV spectral lines of highly-charged Hf, Ta and Au ions observed with an electron beam ion trap," by Ilija N Draganić et al.
America Measures Up
The first week in March is Weights and Measures Week, celebrated jointly by NIST and the National Conference of Weights and Measures (NCWM), an organization that includes not only state and local regulators but also regulated industries and consumer interests. The annual event recognizes the many ways that weights and measures contribute to the economy. Activities vary from state to state.
Temperature Symposium Next Month
NIST is co-sponsoring the 9th Annual Temperature Symposium in Anaheim, CA, from March 19-23, and PML's Sensor Science Division is providing leadership for the event. Greg Strouse is the General Committee Chair, and Dawn Cross is serving as Conference Secretary. The International Program Committee Chair is Wes Tew, and the Vice Chair is Howard Yoon. Chris Meyer will edit the conference proceedings, which will be published by the American Institute of Physics (AIP).
Nanoelectronics Metrology Proceedings Published
The proceedings for the NIST-sponsored 2011 International Conference on Frontiers of Characterization and Metrology for Nanoelectronics was published in December by the American Institute of Physics (AIP). These hardbound proceedings contain full manuscripts for the poster and oral presentations from the successful conference, which was held last spring at the MINATEC Campus in Grenoble, France. The manuscripts are focused on the frontiers and innovation needed in characterization and metrology. Among the many topics covered were 3D Integration Metrology, Atom Probe Tomography, Atomic Force Microscopy (AFM), CD Metrology, Electron Tomography, Ellipsometry, Helium Ion Microscopy, Scanning Electron Microscopy (SEM), Scatterometry, Transmission Electron Microscopy (TEM), and X-Ray Diffraction/Reflectometry.
Papers from past proceedings in the conference series have recently become available free-of-charge due to a recent agreement reached between NIST and the AIP. These papers represent over 15 years of outstanding research and overviews of critical topics collected from world-wide experts in the field of semiconductor characterization and metrology. The archived papers are available on-line.
Possible Detector Alternative
The increasing cost and scarcity of helium-3, used in high-quality neutron detectors for radiation portal monitors and research purposes, has prompted worldwide interest in non-helium technologies. A September 2011 Government Accountability Office assessment of various alternatives cites work from PML's Radiation & Biomolecular Physics Division on "a neutron detector that observes the ultraviolet light emitted by noble gas excimers—molecules in an excited electronic state—that form after boron-10 or lithium-6 absorbs a neutron in a noble gas, such as argon or xenon."
The report notes NIST researchers' conclusion that "after these technologies are explored in laboratory settings, they may become available for integration into neutron detector designs. They could then provide additional options for neutron detector designs and help to further reduce helium-3 demand."
Five by Five
A 2007 paper by Nathan Newbury and William Swann ("Low-noise fiber-laser frequency combs") is among the top five most-cited articles published over the past five years in OSA's Journal of the Optical Society of America B (JOSA B), according to new data from Thomson Reuters Web of Science.
Femto-switching
Recently published findings from a collaboration of scientists at PML's Quantum Physics and Electromagnetics divisions, the NSF Engineering Research Center at the University of Colorado, and colleagues in Germany have been highlighted by a Viewpoint feature in Physics, the APS online magazine. In their paper, "Ultrafast Demagnetization Measurements Using Extreme Ultraviolet Light: Comparison of Electronic and Magnetic Contributions," the researchers report progress in measurements of femtomagnetism, which, they explain, "explores how fast magnetic materials can magnetize or demagnetize—timescales that depend on the coupled motions of charges, spins, atoms, and phonons in materials."
Way Cool!
Bill Phillips of PML's Quantum Measurement Division continues to dazzle school groups with variations on his popular talk titled "Time, Einstein, and the Coolest Stuff in the Universe." In January, among other venues, he addressed an audience of 1,000 at McKinley Technology High School in Washington, DC. The presentation was videotaped and will soon be available on NIST's YouTube channel and in DVD form.
Arts & Sciences
Physical Review A’s eye-catching Kaleidoscope feature includes a colorful graphic from a paper by numerous PML authors in the Quantum Measurement Division including Carl Williams, Charles Clark and Eite Tiesinga. The complete set of images from the authors’ Figure 1 is shown below.
Viewpoint
A recent paper in Physical Review Letters from Jun Ye's group in the Time and Frequency Division was selected for a Viewpoint article.
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| A schematic of the experimental setup.(Click image for a larger version) |
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Vox Populi
An invited review article in the AIP Review of Scientific Instruments on single-photon sources and detectors by Jingyun Fan, Alan Migdall, and Sergey Polyakov of PML's Quantum Measurement Division, and M.D. Eisaman (now in the Sustainable Energy Technologies Department at Brookhaven National Laboratory) has proven persistent popular. Since it was published in July 2011, it has appeared continuously on RSI’s list of the Top 20 downloaded papers since publication, rising to No. 1 in September and still at No. 2 in November.
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; "A schematic of the experimental setup.")