You searched on: Author: leonard hanssen
Displaying records 11 to 20 of 164 records.
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11. A Determination Study of The Cavity Emissivity of the Eutectic Fixed Points Co-C, Pt-C and Re-C
Leonard M Hanssen, Yohsiro Yamada, Pieter Bloembergen, Pablo Castro, Boris Wilthan, Sergey Mekhontsev
The eutectics Co-C, Pt-C and Re-C, with phase transition temperatures of 1597 K, 2011 K, and 2747 K, respectively, are presently investigated for their suitability to serve as reference points for dissemination of T (and T90) within the context of th ...
12. Increased responsivity pyroelectric radiometer with dome input and temperature control
George P Eppeldauer, Jinan Zeng, Leonard M Hanssen
Pyroelectric radiometers with noise-equivalent-power (NEP) close to 1 nW/Hz¿ have been developed to measure less than 1 microwatt radiant power levels at room temperature to 25 micrometer. The radiometers will be used as transfer standards for routin ...
13. Absorption of Thermal Radiation by Burning Polymers
Gregory T Linteris, Mauro Zammarano, Boris Wilthan, Leonard M Hanssen
In large-scale fires, the input of energy to burning materials occurs predominantly by radiative
transfer. The in-depth absorption of radiant energy by a polymer influences its ignition time and burning rate. The present investigation examines two m ...
14. Preliminary characterization study of a gold-coated concentrator for hemispherical longwave irradiance measurements
Jinan Zeng, Leonard M Hanssen, Ibrahim Reda, Jonathan Scheuch
We report the preliminary characterization results of a gold-coated concentrator used for longwave irradiance measurements. Throughput measurements of the concentrator are conducted at 1.562 μm and 10.15 μm using two different approaches ...
15. Very black infrared detector from vertically aligned carbon nanotubes and electric-field poling of lithium tantalate
John H Lehman, Aric Warner Sanders, Leonard M Hanssen, Boris Wilthan, Jinan Zeng, Christopher Jensen
Vertically aligned multiwall carbon nanotubes were grown by water-assisted chemical vapor deposition on a large-area lithium tantalate pyroelectric detector. The processing parameters are nominally identical to those by which others have achieved the ...
16. Spectral irradiance responsivity calibration of InSb radiometers using the improved IR-SIRCUS at NIST
Jinan Zeng, Howard W Yoon, George P Eppeldauer, Leonard M Hanssen, Joseph Paul Rice
The spectral irradiance responsivity calibrations of InSb radiometers measured on the tunable-laser based Infrared Spectral Irradiance and Radiance Responsivity Calibration with Uniform Sources (IR-SIRCUS) facility are discussed. This work describes ...
17. Development of an infrared optical scattering instrument from 1 um to 5 um
Jinan Zeng, Leonard M Hanssen
The wavelength coverage of the IR optical scattering instrument developed at the National Institute of Standards and Technology has been extended to cover the continuous range from 1 um to 5 um. Besides the previously available diode lasers at wavele ...
18. Extension of the NIST spectral responsivity scale to the infrared using improved-NEP pyroelectric detectors
George P Eppeldauer, Jinan Zeng, Howard W Yoon, Boris Wilthan, Thomas C Larason, Leonard M Hanssen
Routine NIST spectral responsivity calibrations are needed for the infrared range. Low NEP pyroelectric radiometers have been developed for traditional monochromator applications to extend the responsivity scale to the infrared. After NEP tests, the ...
19. Thermal Performance of Fire Resistive Materials III. Fire Test on a Bare Steel Column
NIST Interagency/Internal Report (NISTIR)
Dale P Bentz, Leonard M Hanssen, Boris Wilthan
This report is part III in an ongoing series concerning the characterization and modeling of the thermal performance of fire resistive materials (FRMs). In part I, a methodology for characterizing FRMs to provide quantitative material property input ...
20. Calibration of the spectral radiant power responsivity of windowed pyroelectric radiometers from 785 nm to 14 ¿m
Leonard M Hanssen, Jinan Zeng
As part of the optical detector characterization program at the Optical Technology Division at NIST, we have established a
capability for the calibration of spectral radiant power responsivity in the infrared from 785 nm to 14 μm. We have ...