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(Audio Part 2 of 2) Oral history interview of John W. Cahn, Thursday, May 30, 2013, / with J. William Gadzuk, William Boettinger, Frank Gayle, Jonathan Guyer, Mike Moldover, and Jack Rush.
No full textOral History interview of John W. Cahn conducted on Thursday, May 30, 2013 at the National Institute of Standards and Technology in Gaithersburg, Maryland
(Transcript) Oral history interview of John W. Cahn, Thursday, May 30, 2013, / with J. William Gadzuk, William Boettinger, Frank Gayle, Jonathan Guyer, Mike Moldover, and Jack Rush.
No full textOral History interview of John W. Cahn conducted on Thursday, May 30, 2013 at the National Institute of Standards and Technology in Gaithersburg, Maryland
James Bergquist
No full textJAMES BERGQUIST
NBS/NIST (Boulder): 1978-2012
INDUCTED: 2013
B: 1947, Cheyenne, Wyoming
EDUCATION:
University of Notre Dame, BS (Physics), 1970
University of Colorado, PhD (Physics), 1977
CITATION:
For pioneering development of the world’s most accurate atomic clocks based on electromagnetically trapped single ions and for the development of the world’s most stable lasers.
POSITIONS HELD AT NBS/NIST:
NRC Postdoctoral Fellow, Time and Frequency Division (TFD), Physics Laboratory (Boulder), 1978-1979 Physicist, Ion Storage Group, TFD, Physics Laboratory (Boulder), 1980-2008
NIST Fellow, Ion Storage Group, TFD, Physical Measurement Laboratory (Boulder), 2008-2012
HONORS:
NIST Bronze Medal (1981) and U.S. Department of Commerce Gold Medals (1985, 2001, 2008)
NIST Edward Uhler Condon Award (2001) and NIST Samuel Wesley Stratton Award (2009)
Elected Fellow of NIST (2008)
Fellow of the American Physical Society (1989); Fellow of the Optical Society of America (1997)
William F. Meggars Award in Precision Measurement, Optical Society of America (2002)
Rabi Award, IEEE Frequency Control Symposium (2006)
Herbert P. Broida Prize for Spectroscopy, American Physical Society (2007)
Arthur Schawlow Prize in Laser Science, American Physical Society (2008)
Election to National Academy of Sciences (2009); European Frequency and Time Award (2011)
MEMBERSHIPS:
American Physical Society
Optical Society of America
PUBLICATIONS:
More than 180 publications including:
Bergquist, J.C., Hulet, R.G., Itano, W.M. and Wineland, D.J., “Observation of Quantum Jumps in a Single Atom,” Phys. Rev. Lett. 57, 1699-1702 (1986)
Diedrich, F., Bergquist, J.C., Itano, W.M., and Wineland, D.J., “Laser Cooling to the Zero Point Energy of Motion,” Phys. Rev. Lett. 62, 403-406 (1989)
Young, B.C., Cruz, F.C., Bergquist, J.C., and Itano, W.M., “Visible Lasers with Subhertz Linewidths,” Phys. Rev. Lett. 82, 3799-3802 (1999)
Bergquist, J.C., Jefferts, S.R., and Wineland, D.J., “Time Measurement at the Millennium,” Phys. Today 54, 37-42 (2001)
Bize, S., Diddams, S.A., Tanaka, U., Tanner, C.E., Oskay, W.H., Drullinger, R.E., Parker, T.E., Heavner, T.P., Jefferts, S.R., Hollberg, L., Itano, W.M., and Bergquist, J.C., “Testing the Stability of Fundamental Constants with the 199Hg+ Single-Ion Optical Clock,” Phys. Rev. Lett. 90, 150802-4 (2003)
Rosenband, T., Hume, D.B., Schmidt, P.O., Chou, C.W., Brusch, A., Lorini, L., Oskay, W.H., Drullinger, R.E., Fortier, T.M., Stalnaker, J.E., Diddams, S.A., Swann, W.C., Newbury, N.R., Itano, W.M., Wineland, D.J., and Bergquist, J.C., “Frequency Ratio of Al+ and Hg+ Single-Ion Optical Clocks; Metrology at the 17th Decimal Place,” Science 319, 1808-1812 (2008
Measurement of Scattering and Absorption Cross Sections of Dyed Microspheres
No full textMeasurements of absorbance and fluorescence emission were carried out on aqueous suspensions of polystyrene (PS) microspheres with a diameter of 2.5 �m using a spectrophotometer with an integrating sphere detector. The apparatus and the principles of measurements were described in our earlier publications. Microspheres with and without green BODIPY@ dye were measured. Placing the suspension inside an integrating sphere (IS) detector of the spectrophotometer yielded (after a correction for fluorescence emission) the absorbance (called A in the text) due to absorption by BODIPY@ dye inside the microsphere. An estimate of the absorbance due to scattering alone was obtained by subtracting the corrected BODIPY@ dye absorbance (A) from the measured absorbance of a suspension placed outside the IS detector (called A1 in the text). The absorption of the BODIPY@ dye inside the microsphere was analyzed using an imaginary index of refraction parameterized with three Gaussian-Lorentz functions. The Kramer-Kronig relation was used to estimate the contribution of the BODIPY@ dye to the real part of the microsphere index of refraction. The complex index of refraction, obtained from the analysis of A, was used to analyze the absorbance due to scattering ((A1- A) in the text). In practice, the analysis of the scattering absorbance, A1-A, and the absorbance, A, was carried out in an iterative manner. It was assumed that A depended primarily on the imaginary part of the microsphere index of refraction with the other parameters playing a secondary role. Therefore A was first analyzed using values of the other parameters obtained from a fit to the absorbance due to scattering, A1-A, with the imaginary part neglected. The imaginary part obtained from the analysis of A was then used to reanalyze A1-A, and obtain better estimates of the other parameters. After a few iterations, consistent estimates were obtained of the scattering and absorption cross sections in the wavelength region 300 nm to 800 nm
Weathering Patterns of Ignitable Liquids with the Advanced Distillation Curve Method
No full textOne can take advantage of the striking similarity of ignitable liquid vaporization (or weathering) patterns and the separation observed during distillation to predict the composition of residual compounds in fire debris. This is done with the advanced distillation curve (ADC) metrology, which separates a complex fluid by distillation into fractions that are sampled, and for which thermodynamically consistent temperatures are measured at atmospheric pressure. The collected sample fractions can be analyzed by any method that is appropriate. Analytical methods we have applied include gas chromatography (with flame ionization, mass spectrometric and sulfur chemiluminescence detection), thin layer chromatography, FTIR, Karl Fischer coulombic titrimetry, refractometry, corrosivity analysis, neutron activation analysis and cold neutron prompt gamma activation analysis. We have applied this method on product streams such as finished fuels (gasoline, diesel fuels, aviation fuels, rocket propellants), crude oils (including a crude oil made from swine manure) and waste oils streams (used automotive and transformer oils). In this paper, we present results on a variety of ignitable liquids that are not commodity fuels, chosen from the Ignitable Liquids Reference Collection (ILRC). These measurements are assembled into a preliminary database. From this selection, we discuss the significance and forensic application of the temperature data grid and the composition explicit data channel of the ADC
A Critical Compilation of Energy Levels, Spectral Lines, and Transition Probabilities of Singly Ionized Silver, Ag II
No full textAll available experimental measurements of the spectrum of the Ag+ ion are critically reviewed. Systematic shifts are removed from the measured wavelengths. The compiled list of critically evaluated wavelengths is used to derive a comprehensive list of energy levels with well-defined uncertainties. Eigenvector compositions and level designations are found in two alternate coupling schemes. Some of the older work is found to be incorrect. A revised value of the ionization energy, 173283(7) cm?1, equivalent to 21.4844(8) eV, is derived from the new energy levels. A set of critically evaluated transition probabilities is given
NIST System for Measuring the Directivity Index of Hearing Aids under Simulated Real-Ear Conditions
No full textThe directivity index is a parameter that is commonly used to characterize the performance of directional hearing aids, and is determined from the measured directional response. Since this response is different for a hearing aid worn on a person as compared to when it is in a free field, directivity index measurements of hearing aids are usually done under simulated real-ear conditions. Details are provided regarding the NIST system for measuring the hearing aid directivity index under these conditions and how this system is used to implement a standardized procedure for performing such measurements. This procedure involves a sampling method that utilizes sound source locations distributed in a semi-aligned zone array on an imaginary spherical surface surrounding a standardized acoustical test manikin. The capabilities of the system were demonstrated over the frequency range of one-third-octave bands with center frequencies from 200 Hz to 8000 Hz through NIST participation in an inter-laboratory comparison. This comparison was conducted between eight different laboratories of members of Working Group S3/WG48, Hearing Aids, established by Accredited Standards Committee S3, Bioacoustics, which is administered by the Acoustical Society of America and accredited by the American National Standards Institute. Directivity measurements were made for a total of six programmed memories in two different hearing aids and for the unaided manikin with the manikin right pinna accompanying the aids. Omnidirectional, cardioid, and bidirectional response patterns were measured. Results are presented comparing the NIST data with the reference values calculated from the data reported by all participating laboratories
Recommendations for Improving Consistency in the Radiation Fields Used During Testing of Radiation Detection Instruments for Homeland Security Applications
No full textSeveral measurements and calculations were performed to illustrate the differences that can be observed in the determination of exposure rate or ambient dose equivalent rate used for testing radiation detection systems against consensus standards. The large variations observed support our recommendation that better consistency in the test radiation fields can be achieved by specifying the source activity and testing distance instead of the field strength
Kiloampere, Variable-Temperature, Critical-Current Measurements of High-Field Superconductors
No full textWe review variable-temperature, transport critical-current (Ic) measurements made on commercial superconductors over a range of critical currents from less than 0.1 A to about 1 kA. We have developed and used a number of systems to make these measurements over the last 15 years. Two exemplary variable-temperature systems with coil sample geometries will be described: a probe that is only variable-temperature and a probe that is variable-temperature and variable-strain. The most significant challenge for these measurements is temperature stability, since large amounts of heat can be generated by the flow of high current through the resistive sample fixture. Therefore, a significant portion of this review is focused on the reduction of temperature errors to less than ±0.05 K in such measurements. A key feature of our system is a pre-regulator that converts a flow of liquid helium to gas and heats the gas to a temperature close to the target sample temperature. The pre-regulator is not i
Ugo Bertocci
No full textUGO BERTOCCI
NBS/NIST (Gaithersburg): 1971-1992
INDUCTED: 2013
B: 1926, Derna, Libya
EDUCATION:
University of Milan, Italy, Doctorate, (Industrial Chemistry), 1950
CITATION:
For the development of advanced electrochemical measurements for corrosion science and electrodeposition.
POSITIONS HELD AT NBS/NIST:
Research Chemist, Corrosion Group, Metallurgy Division, Materials Science and Engineering Laboratory, 1971- 1992
Guest Researcher, Materials Science and Engineering Division, Material Measurement Laboratory, 1996-2013
HONORS:
NIST Bronze Medal (1980) and U.S. Department of Commerce Silver Medal (1989)
NCS-ECS Blum Award (1992)
Fellow, Electrochemical Society (2009)
Fellow, American Association for the Advancement of Science (2009)
MEMBERSHIPS:
Electrochemical Society
International Society of Electrochemistry
American Chemical Society
American Association for the Advancement of Science
PUBLICATIONS:
More than 100 publications including:
Bertocci, U., “Separation between Deterministic Response and Random Fluctuations by Means of the Crosspower Spectrum in the Study of Electrochemical Noise”, J. Electrochem. Soc. 128, 3 (1981)
Bertocci, U. and Yang-Xiang, Ye, “An Examination of Current Fluctuations during Pit Initiation in Fe-Cr Alloys”, J. Electrochem. Soc. 131, 5 (1984) Bertocci, U. and Huet, F., “Noise-Analysis Applied to Electrochemical Systems”, Corrosion, 51, 2 (1995)
Bertocci, U., Gabrielli, C., Huet, F., and Keddam, M., “Noise Resistance Applied to Corrosion Measurements I, Theoretical Analysis”, J. Electrochem. Soc., 144, 31 (1997)
Bertocci, U., C., Huet, F., Keddam, M., and Rousseau. P., “Noise Resistance Applied to Corrosion Measurements II”, Experimental Tests”, J. Electrochem. Soc., 144, 31 (1997)
Kongstein, O.E., Bertocci, U., and Stafford, G.S., “In Situ Stress Measurements during Copper Electrodeposition on (111)-Textured Au”, J. Electrochem. Soc., 152, C116 (2005