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Oral history interview of Randall S. Caswell, Wednesday, November 14, 2012, / with J. William Gadzuk, Stephen N. Seltzer, David M. Gilliam, Allan D. Carlson, John J. Rush, David Lide.
No full textDr. Caswell came to the National Bureau of Standards (NBS) in 1952 and retired from the National Institute of Standards and Technology (NIST) in 1994. Dr. Caswell discusses his career and accomplishments as a Physicist at NBS/NIST. He served as NIST host and founding member of the Council on Ionizing Radiation Measurements and Standards
New Measurement Service for Determining Pressure Sensitivity of Type LS2aP Microphones by the Reciprocity Method
No full textA new National Institute of Standards and Technology (NIST) measurement service has been developed for determining the pressure sensitivities of American National Standards Institute and International Electrotechnical Commission type LS2aP laboratory standard microphones over the frequency range 31.5 Hz to 20 000 Hz. At most frequencies common to the new service and the old service, the values of the expanded uncertainties of the new service are one-half the corresponding values of the old service, or better. The new service uses an improved version of the system employed by NIST in the Consultative Committee for Acoustics, Ultrasound, and Vibration (CCAUV) key comparison CCAUV.A-K3. Measurements are performed using a long and a short air-filled plane-wave coupler. For each frequency in the range 31.5 Hz to 2000 Hz, the reported sensitivity level is the average of data from both couplers. For each frequency above 2000 Hz, the reported sensitivity level is determined with data from the short coupler only. For proof test data in the frequency range 31.5 Hz to 2000 Hz, the average absolute differences between data from the long and the short couplers are much smaller than the expanded uncertainties
Microhotplate temperature sensor calibration and BIST
No full textIn this paper we describe a novel long-term microhotplate temperature sensor calibration technique suitable for Built-In Self Test (BIST). The microhotplate thermal resistance (thermal efficiency) and the thermal voltage from an integrated platinum-rhodium thermocouple were calibrated against a freshly calibrated four-wire polysilicon microhotplate-heater temperature sensor (heater) that is not stable over long periods of time when exposed to higher temperatures. To stress the microhotplate, its temperature was raised to around 400 °C and held there for days. The heater was then recalibrated as a temperature sensor, and microhotplate temperature measurements were made based on the fresh calibration of the heater, the first calibration of the heater, the microhotplate thermal resistance, and the thermocouple voltage. This procedure was repeated 10 times over a period of 80 days. The results show that the heater calibration drifted substantially during the period of the test while the microhotplate thermal resistance and the thermocouple-voltage remained stable to within about plus or minus 1 °C over the same period. Therefore, the combination of a microhotplate heater-temperature sensor and either the microhotplate thermal resistance or an integrated thin film platinum-rhodium thermocouple can be used to provide a stable, calibrated, microhotplate-temperature sensor, and the combination of the three sensor is suitable for implementing BIST functionality. Alternatively, if a stable microhotplateheater temperature sensor is available, such as a properly annealed platinum heater-temperature sensor, then the thermal resistance of the microhotplate and the electrical resistance of the platinum heater will be sufficient to implement BIST. It is also shown that aluminum- and polysilicon-based temperature sensors, which are not stable enough for measuring high microhotplate temperatures (>220 °C) without impractically frequent recalibration, can be used to measure the silicon substrate temperature if never exposed to temperatures above about 220 °C
Albert C. Parr
No full textAlbert C. Parr
Inducted: 2011
Citation: For technical leadership in the establishment of a national measurement system for radiometry and photometry based upon absolute detectors.
Tenure: 1980-2007
Birth: 1942, Tooele, Utah
Education:
Oregon State University, BS (Mathematics) and BS (Physics), 1964
University of Chicago, MS (Physics), 1965
University of Chicago, PhD (Physics), 1971
Positions held:
Physicist, Radiation Physics Division, Center for Radiation Research, NML, 1980-1986
Leader, Spectral Radiometry Group, Radiometric Physics Division, Center for Radiation Research, NML, 1986-1991
Chief, Radiometric Physics Division/Optical Technology Division, Physics Laboratory, 1991-2007
NIST Guest Researcher, Physics Laboratory, 2007-Present
Honors:
US Department of Commerce Gold Medal (2003)
Fellow, American Physical Society (1997)
Washington Academy of Sciences Physical Sciences Award (2006)
Memberships:
Member, American Physical Society (APS), Optical Society of America (OSA), International Council on Illumination (CIE)
NIST Liaison, Council for Optical Radiation Measurements (CORM) Board of Directors
International Advisory Committee for NEWRAD (New Developments in Optical Radiometry) Conference
NIST Representative, Consultative Committee for Photometry and Radiometry (CCPR)
Chair, CCPR Working Group on Key Comparisons
Publications:
More than 115 publications including:
Parr, A.C., Datla, R.U., and Gardner, J.L., editors, �Optical Radiometry,� Elsevier Academic Press, Amsterdam (2005)
Parr, A.C., A National Measurement System for Radiometry, Photometry, and Pyrometry Based Upon Absolute Detectors NIST Technical Note 1421 (1996)
Parr, A.C., et al., �Selective Population of Spin-orbit Levels in the Autoionization of a Polyatomic Molecule: Branching Ratios and Asymmetry Parameters for the Tanaka-Ogawa Rydberg Series in CO2,� J. Chem. Phys. 100, 8768 (1994)
Parr, A.C. and Datla, R.U., �Introduction to Optical Radiometry,� Optical Radiometry, ed. by A.C. Parr, et al. Elsevier Academic Press, Amsterdam, pp. 1-34 (2005)
Parr, A.C., Fowler, J.B., and Ebner, S., �Low Background Infrared Calibration Facility at the National Bureau of Standards,� Proceeding SPIE 940 (SPIE, Bellingham, WA) p 26 (1988)
Parr, A.C., �Determination of the Constants of Total Radiation From a Black Body,� in Century of Excellence in Measurements, Standards, and Technology: a Chronicle of Selected NBS/NIST Publications 1901-2000, ed. by D.R. Lide, NIST Special Publication 958 (2001
(Transcript) Oral history interview of Richard N. Wright, January 10, 2011 / [persons present]: David Lide, Jim Gross, Richard Wright, Dave Didion, Hans Oser
No full textThe Use of Filtered Radiometers for Radiance Measurement
No full textA methodology for using a calibrated filter radiometer to measure and monitor the spectral radiance of calibration sources is described. An example is presented using the NIST calibration sphere source that is used to support the NASA Earth Observing remote-sensing program
Best practice guidelines for pre-launch characterization and calibration of instruments for passive optical remote sensing
No full textThe pre-launch characterization and calibration of remote sensing instruments should be planned and carried out in conjunction with their design and development to meet the mission requirements. The onboard calibrators such as blackbodies and the sensors such as spectral radiometers should be characterized and calibrated using SI traceable standards. In the case of earth remote sensing, this allows intercomparison and intercalibration of different sensors in space to create global time series of climate records of high accuracy where some inevitable data gaps can be easily bridged. The recommended best practice guidelines for this pre-launch effort is presented based on experience gained at National Institute of Standards and Technology (NIST), National Aeronautics and Space Administration (NASA) and National Oceanic and Atmospheric Administration (NOAA) programs over the past two decades. The currently available radiometric standards and calibration facilities at NIST serving the remote sensing community are described. Examples of best practice calibrations and intercomparisons to build SI (international System of Units) traceable uncertainty budget in the instrumentation used for preflight satellite sensor calibration and validation are presented
Development of Multicolor Flow Cytometry Calibration Standards: Assignment of Equivalent Reference Fluorophores (ERF) Unit
No full textA procedure is described for assigning the number of equivalent reference fluorophores (ERF) values to microspheres labeled with a fluorophore designed to produce a fluorescence response in a given fluorescence channel of a multicolor flow cytometer. A fluorimeter was calibrated by a series of solutions of the reference fluorophores. The fluorimeter was used to obtain the microsphere fluorescence intensity, and a multicolor flow cytometer was used to obtain the microsphere concentration. The microsphere fluorescence intensity and the concentration were used to obtain the value of ERF for each model microsphere calibration standard. The procedure is described in detail only for microspheres with allophycocyanin (APC) immobilized on the surface. ERF values were also determined for microsphere calibrators for three other fluorescence channels: fluorescein isothiocyanate (FITC), phycoerythrin (PE), and Pacific Blue(PB). The four model microsphere calibrators provide a one point calibration for the four channels of a flow cytometer. By using software controls and changing the photomultiplier voltages, it is possible to obtain a multipoint calibration for each fluorescence channel using each microsphere calibrator
Portrait of Albert Parr
No full textInducted into the NIST Gallery of Distinguished Scientists, Engineers, and Administrators in 2011 for “technical leadership in the establishment of a national measurement system for radiometry and photometry based upon absolute detectors.
Tenure at NIST: 1980-2007.
Birth: 1942, Tooele, Utah.
Education:
B.S., Mathematics and Physics, Oregon State University, 1964.
M.S., Physics, University of Chicago, 1965.
Ph.D., Physics,University of Chicago, 1971.
Positions held:
Physicist, Radiation Physics Division, Center for Radiation Research, NML, 1980-1986.
Leader, Spectral Radiometry Group, Radiometric Physics Division, Center for Radiation Research, NML, 1986-1991.
Chief, Radiometric Physics Division/Optical Technology Division, Physics Laboratory, 1991-2007.
NIST Guest Researcher, Physics Laboratory, 2007
Combining results from multiple evaluations of the same measurand
No full textAccording to the Guide to the Expression of Uncertainty in Measurement (GUM), a result of measurement consists of a measured value together with its associated standard uncertainty. The measured value and the standard uncertainty are interpreted as the expected value and the standard deviation of a state-of-knowledge probability distribution attributed to the measurand. We discuss the term metrological compatibility introduced by the International Vocabulary of Metrology, third edition (VIM3) for lack of significant differences between two or more results of measurement for the same measurand. Sometimes a combined result of measurement from multiple evaluations of the same measurand is needed. We propose an approach for determining a combined result which is metrologically compatible with the contributing results