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Search Publications by: James A. Fedchak (Fed)

Displaying 76 - 93 of 93

Recommended Practices for the use of Spinning Rotor Gauges in Inter-laboratory Comparisons

February 12, 2015

Author(s)

James A. Fedchak, Karl Jousten, Kenta Arai, Janez Setina

The spinning rotor gauge (SRG) is a common transfer standard in key comparisons (KCs) and other intercomparisons for pressures in the range of 1.0 × 10-4 Pa to 1.0 Pa. To make absolute pressure measurements using a SRG, a calibration factor, known as the

Bilateral key comparison CCM.P-K3.1 for absolute pressure measurements from 3 * 10-6 Pa to 9 * 10-4 Pa

January 1, 2014

Author(s)

James A. Fedchak

This report describes a bi-lateral key-comparison between the National Institute of Standards and Technology (NIST) and Physikalisch-Technische Bundesanstalt (PTB) for absolute pressure in the range of 3×10-6 Pa to 9×10-4 Pa. This comparison was a follower

Final report of key comparison CCM.P-K12 for very low helium flow rates (leak rates)

January 1, 2013

Author(s)

James A. Fedchak, Blaza Toman, Karl Jousten

Quantitative leak tests with vacuum technology have become an important tool in industry for safety and operational reasons and to meet environmental regulations. In lack of a relevant key comparison, so far, there are no calibration measurement

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

Precise conductance measurements of a pinhole orifice using a constant-pressure flowmeter

December 1, 2012

Author(s)

James A. Fedchak, Dana R. Defibaugh

A pinhole orifice with a known conductance can be used as the basis of a flowmeter. Commercially available laser-drilled pinhole orifices with diameters ranging from 1.0 μm to 50 μm can have conductances ranging from about 0.1 μL/s to 200 μL/s in the

Interlaboratory comparison of Helium Low Gas Flow Measurements in the range 10-13 to 10-11 mol/s (10-9 to 10-7 cm3/s)

March 1, 2010

Author(s)

Dana R. Defibaugh, Patrick J. Abbott, James A. Fedchak

An interlaboratory comparison (ILC) of helium low flow measurement capability was recently completed. The comparison was piloted by The National Institute of Standards and Technology (NIST); the majority of the data was taken over a period of approximately

Intercomparison of the LBIR Absolute Cryogenic Radiometers to the NIST Optical Power Measurement Standard

August 1, 2006

Author(s)

Adriaan C. Carter, James A. Fedchak, Raju V. Datla

The Low Background Infrared (LBIR) facility at the National Institute of Standards and Technology (NIST) presently maintains four absolute cryogenic radiometers (ACRs) which serve as standard reference detectors for infrared calibrations performed by the

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

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