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Search Publications by: James A. Fedchak (Fed)

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Displaying 26 - 46 of 46

Vacuum Furnace for Degassing Stainless-Steel Vacuum Components

March 1, 2018
Author(s)
James A. Fedchak, Julia K. Scherschligt, Daniel S. Barker, Stephen P. Eckel, Alex P. Farrell, Makfir Sefa
Ultra-high vacuum systems must often be constructed of materials with ultra-low outgassing rates to achieve pressure of 10-6 Pa and below. In such a case, any component placed into the ultra-high vacuum system must also be constructed of materials with

Development of a new UHV/XHV pressure standard (Cold Atom Vacuum Standard)

November 10, 2017
Author(s)
Julia Scherschligt, James A. Fedchak, Daniel Barker, Stephen Eckel, Nikolai Klimov, Constantinos Makrides, Eite Tiesinga
The National Institute of Standards and Technology has recently begun a program to develop a primary pressure standard that is based on ultra-cold atoms, covering a pressure range of 1 × 10-6 Pa to 1 × 10-10 Pa and possibly lower. These pressures

Perspectives for a new realization of the pascal by optical methods

October 24, 2017
Author(s)
Jay H. Hendricks, Karl Jousten, Jack A. Stone Jr., Patrick F. Egan, Tom Rubin, Christof Gaiser, Rene Schodel, James A. Fedchak, Jacob E. Ricker, Jens Fluegge, Stephen P. Eckel, Julia K. Scherschligt, Daniel S. Barker, Kevin O. Douglass, Gregory F. Strouse, Uwe Sterr, Waldimir Sabuga
Since the beginning of measurement of pressure in the 17th century, the unit of pressure has been defined by the relationship of force per unit area. The present state of optical technology now offers the possibility of using a thermodynamic definition

Toward 3D printed hydrogen storage materials made with ABS-MOF composites

September 26, 2017
Author(s)
Megan C. Kreider, Zeeshan Ahmed, Makfir Sefa, James A. Fedchak, Julia Scherschligt, Michael Bible, Nikolai Klimov, Bharath Natarajan, Hartings Mathew
The push to advance efficient, renewable, and clean energy sources has brought with it an effort to generate materials that are capable of storing hydrogen. Metal-organic framework materials (MOFs) have been the focus of many such studies as they are

Impact of Varying Vacuum Levels on Self-Heating in Photonic Thermometers

July 1, 2017
Author(s)
Zeeshan Ahmed, Nikolai N. Klimov, James R. Hands, James A. Fedchak
Here we examine the impact of vacuum levels on self-heating in photonic crystal cavity thermometers. Our results suggest that background gas pressure has a negligible impact on self- heating correction to the temperature-wavelength calibration.

Final report on the key comparison, CCM.PK15 in the pressure rangefrom 1.0 x 10-4 Pa to 1.0 Pa

January 30, 2017
Author(s)
Christian Wuethrich, Hitoshi Akimichi, Mercede Bergoglio, James A. Fedchak, Karl Jousten, Sueng Soo Hong, Jorge T. Guzman
The comparison CCM.M.P-K14 is a key comparison in pressure involving six laboratories in three regional metrological organizations (RMO). The measurand of the comparison is the accommodation coefficient of two spinning rotating gauge characterized in

Gas Uptake of 3-D Printed Acrylonitrile Butadiene Styrene (ABS) Using a Vacuum Apparatus Designed for Absorption and Desorption Studies

October 25, 2016
Author(s)
Makfir Sefa, Zeeshan Ahmed, James A. Fedchak, Nikolai Klimov, Julia Scherschligt
We describe a vacuum apparatus for determining the outgassing rate into vacuum, the diffusion coefficient, and the amount of gas absorbed for various materials. The diffusion coefficient is determined from a model applied to time-dependent desorption data

How to Build a Vacuum Spring-Transport Package for Spinning Rotor Gauges

April 7, 2016
Author(s)
James A. Fedchak, Julia K. Scherschligt, Makfir Sefa
The spinning rotor gauge (SRG) is a high-vacuum gauge often used to as a secondary or transfer standard for vacuum pressures in the range of 1.0 × 10-4 Pa to 1.0 Pa. In this application, the gauges are frequently transported to laboratories for calibration

Building a Spring-Transport Mechanism for Spinning Rotor Gauges

April 3, 2015
Author(s)
James A. Fedchak, Julia K. Scherschligt, Makfir Sefa, Nick Phandinh
Spinning rotor gauges (SRGs) are widely used as transfer standards in inter-laboratory comparisons and as secondary standards by calibration laboratories. In both of these applications, it is necessary to ship the SRG for calibration, often internationally

Long-term stability of metal-envelope enclosed ionization gauges

December 1, 2012
Author(s)
James A. Fedchak, Dana R. Defibaugh
Ionization vacuum gauges are used as secondary standards by calibration laboratories and as transfer standards in intercomparisons among metrology laboratories. A quantitative measurement of gauge stability with respect to the gauge calibration factor is

Low Background Temperature Calibration of Infrared Blackbodies

March 23, 2006
Author(s)
Adriaan C. Carter, Raju V. Datla, Timothy M. Jung, Allan W. Smith, James A. Fedchak
The Low Background Infrared (LBIR) facility at the National Institute of Standards and Technology (NIST) has performed 10 calibrations of low-background blackbodies since 2001 when the calibration facility and calibration method for low-background

Measurement of Small Apertures

March 23, 2006
Author(s)
James A. Fedchak, Adriaan C. Carter, Raju V. Datla
The Low Background Infrared calibration (LBIR) facility at the National Institute of Standards and Technology (NIST) is developing a relative aperture area instrument to measure the areas of apertures with diameters ranging from 5 mm to 0.05 mm. NIST