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Search Publications by: Leonard Hanssen (Fed)

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Displaying 1 - 25 of 175

A pyroelectric detector-based method for low uncertainty spectral irradiance and radiance responsivity calibrations in the infrared using tunable lasers

April 4, 2022
Brian Alberding, John Woodward, Ping-Shine Shaw, Leonard Hanssen, Catherine Cooksey, Joseph P. Rice
The standard uncertainty of detector-based radiance and irradiance responsivity calibrations in the short-wave infrared (SWIR) traditionally has been limited to around 1 % or higher by the low spatial uniformity of detectors used to transfer the scale from

Design and Evaluation of Large Aperture Gallium Fixed Point Blackbody

October 12, 2021
V B. Khromchenko, Sergey Mekhontsev, Leonard Hanssen
To complement existing water bath blackbodies which are now serving as NIST primary standard sources in the temperature range from 15 C to 75 C, a gallium fixed point blackbody has been recently built. The main objectives of the project included creating

Measurement Uncertainty of Surface Temperature Distributions for Laser Powder Bed Fusion Processes

August 10, 2021
David Deisenroth, Sergey Mekhontsev, Brandon Lane, Leonard M. Hanssen, Ivan Zhirnov, Vladimir Khromchenko, Steven Grantham, Daniel Cardenas-Garcia, Alkan Donmez
This paper describes advances in measuring the characteristic spatial distribution of surface temperature and emissivity during laser-metal interaction under conditions relevant for laser powder bed fusion (LPBF) additive manufacturing processes. Detailed

Methods for Quantitative Infrared Directional-Hemispherical and Diffuse Reflectance Measurements Using a Fourier Transform Spectrometer and a Commercial Integrating Sphere

January 20, 2018
Leonard M. Hanssen, Thomas A. Blake, TImothy J. Johnson, Russell G. Tonkyn, Brenda M. Forland, Tanya L. Myers, Carolyn S. Brauer, Yin-Fong Su, Bruce E. Bernacki
Infrared integrating sphere measurements of solid samples are important in providing reference data for contact, standoff and remote sensing applications. At the Pacific Northwest National Laboratory (PNNL) we have developed protocols to measure both the

Low-NEP pyroelectric detectors for calibration of UV and IR sources and detectors

September 5, 2017
George P. Eppeldauer, Vyacheslav B. Podobedov, Leonard Hanssen, P. Yvonne Barnes
Pyroelectric radiometers with spectrally constant response have been developed at NIST with the cooperation of a few detector manufacturers. The new devices have noise-equivalent-power (NEP) values less than 1 nW/Hz^1/2 sufficiently low for use at the

Calibration of spectral responsivity of IR detectors in the range from 0.6 mm to 24 mm

June 15, 2017
Vyacheslav B. Podobedov, George P. Eppeldauer, Leonard M. Hanssen, Thomas C. Larason
We report the upgraded performance of the National Institute of Standards and Technology (NIST) facility for spectral responsivity calibrations of infrared (IR) detectors in both radiant power and irradiance measurement modes. The extension of the

Broadband Radiometric LED Measurements

September 6, 2016
George P. Eppeldauer, P. Yvonne Barnes, Howard W. Yoon, Leonard Hanssen, Vyacheslav B. Podobedov, Robert E. Vest, Uwe Arp, C Cameron Miller
At present, broadband radiometric measurements of LEDs with uniform and low-uncertainty results are not available. Currently, either spectral radiometric measurements or broadband photometric LED measurements are used. The broadband photometric

Design, Developments, and Results from the NIST Additive Manufacturing Metrology Testbed (AMMT)

August 10, 2016
Brandon M. Lane, Sergey Mekhontsev, Steven E. Grantham, Mihaela Vlasea, Justin G. Whiting, Ho Yeung, Jason C. Fox, Clarence J. Zarobila, Jorge E. Neira, Michael L. McGlauflin, Leonard M. Hanssen, Shawn P. Moylan, M A. Donmez, Joseph P. Rice
NIST is developing a facility titled the Additive Manufacturing Metrology Testbed that will enable advanced research into monitoring, controls, process development, and temperature measurement for laser powder bed fusion additive manufacturing and similar

Optical design and initial Results from NIST’s AMMT/TEMPS Facility

May 9, 2016
Steven E. Grantham, Brandon M. Lane, Jorge E. Neira, Sergey Mekhontsev, Leonard M. Hanssen, Mihaela Vlasea
NIST’s Physical Measurement and Engineering Laboratories are jointly developing the Additive Manufacturing Measurement Testbed (AMMT)/ Temperature and Emittance of Melts, Powders and Solids (TEMPS) facilities. These facilities will be co-located on an open

Report on the CCT Supplementary Comparison S1 of Infrared Spectral Normal Emittance/Emissivity

March 15, 2016
Leonard M. Hanssen, Boris Wilthan, Christian Monte, Joerg Hollandt, Jacques Hameury, Jean-Remy Filtz, Ferruccio Girard, Mauro Battuello, Juntaro Ishii
The National Measurement Institutes (NMIs) of the United States, Germany, France, Italy and Japan, have joined in an inter-laboratory comparison of their infrared spectral emittance scales. This action is part of a series of supplementary inter-laboratory

Infrared Optical Properties of Materials

February 24, 2015
Simon G. Kaplan, Leonard M. Hanssen, Raju V. Datla
This document describes the Fourier Transform Infrared Spectrophotometry (FTIS) Facility at the Sensor Science Division (SSD) of the National Institute of Standards and Technology (NIST) to provide the infrared optical properties of materials (IROPM)

Atomic Clock with 1x10 -18 Room-Temperature Blackbody Stark Uncertainty

December 31, 2014
Kyle P. Beloy, Nathan M. Hinkley, Nate B. Phillips, Jeffrey A. Sherman, Marco Schioppo, John H. Lehman, Ari D. Feldman, Leonard M. Hanssen, Christopher W. Oates, Andrew D. Ludlow
The Stark shift due to blackbody radiation (BBR) is a key factor limiting the performance of many atomic frequency standards, with the BBR environment inside the clock apparatus being difficult to characterize at a high level of precision. Here we

Spectral Emissivity Measurements

July 10, 2014
Hiromichi Watanabe, Juntaro Ishii, Hidenobu Wakabayashi, Tomoyuki Kumano, Leonard Hanssen
Chapter 9 describes the wide variety of experimental instrumentation and methods used for spectral emissivity measurements at both ambient and elevated temperatures, along with specific examples of materials studied. There are a number of measurement

New Developments in the NIST Infrared Optical Properties of Materials Program

July 1, 2014
Leonard M. Hanssen, Sergey Mekhontsev, Jinan Zeng, John H. Burnett
The Infrared Optical Properties of Materials program in the Sensor Science Division at the National Institute of Standards and Technology (NIST) continues to upgrade its capabilities to provide comprehensive coverage of measurable infrared optical

Evaluation of dome-input geometry for pyroelectric detectors

June 24, 2013
Jinan Zeng, Leonard M. Hanssen, George P. Eppeldauer
Dome-input pyroelectric radiometers with different black coatings were developed to extend the spectral responsivity scale from near infrared (NIR) to 20 μm. The reflective dome with shiny gold-coating has been known to be an efficient light trap to

Measurements of Infrared Spectral Directional Emittance at NIST - A Status Update

September 12, 2012
Boris Wilthan, Leonard Hanssen, Sergey Mekhontsev
Over the past two decades, the Sensor Science Division at the National Institute of Standards and Technology (NIST) has developed extensive capabilities for the characterization of the infrared optical properties of materials and components. These include