The Experts below are selected from a list of 153 Experts worldwide ranked by ideXlab platform
Martin P. Seah - One of the best experts on this subject based on the ideXlab platform.
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summary of iso tc 201 standard xi iso 17974 2002 surface chemical analysis high resolution auger electron spectrometers Calibration of energy scales for elemental and chemical state analysis
Surface and Interface Analysis, 2003Co-Authors: Martin P. SeahAbstract:This International Standard specifies a method for calibrating the kinetic energy scales of Auger electron spectrometers for elemental and chemical-state analysis at surfaces. It is only applicable to instruments that incorporate an ion gun for sputter cleaning. This International Standard further specifies a method to establish a Calibration schedule, to test for the kinetic energy scale linearity at one intermediate energy, to confirm the uncertainty of the scale Calibration at one low and one high kinetic energy value, to correct for small drifts of that scale and to define the expanded uncertainty of the Calibration of the kinetic energy scale for a confidence level of 95%. This uncertainty includes contributions for behaviours observed in interlaboratory studies but does not cover all of the defects that could occur. This International Standard is not applicable to instruments with kinetic energy scale errors that are significantly non-linear with energy, to instruments operated at relative resolutions poorer than 0.2% in the constant ΔE/E mode or poorer than 1.5 eV in the constant ΔE mode, to instruments requiring tolerance limits of ±0.05 eV or less or to instruments equipped with an electron gun that cannot be operated in the energy range 5–10 keV. This standard does not provide a full Calibration Check, which would confirm the energy measured at each addressable point on the energy scale and should be performed according to the manufacturer's recommended procedures. Crown Copyright © 2003. Published by John Wiley & Sons, Ltd.
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Summary of ISO/TC 201 Standard XI. ISO 17974:2002—Surface chemical analysis—High‐resolution Auger electron spectrometers—Calibration of energy scales for elemental and chemical‐state analysis
Surface and Interface Analysis, 2003Co-Authors: Martin P. SeahAbstract:This International Standard specifies a method for calibrating the kinetic energy scales of Auger electron spectrometers for elemental and chemical-state analysis at surfaces. It is only applicable to instruments that incorporate an ion gun for sputter cleaning. This International Standard further specifies a method to establish a Calibration schedule, to test for the kinetic energy scale linearity at one intermediate energy, to confirm the uncertainty of the scale Calibration at one low and one high kinetic energy value, to correct for small drifts of that scale and to define the expanded uncertainty of the Calibration of the kinetic energy scale for a confidence level of 95%. This uncertainty includes contributions for behaviours observed in interlaboratory studies but does not cover all of the defects that could occur. This International Standard is not applicable to instruments with kinetic energy scale errors that are significantly non-linear with energy, to instruments operated at relative resolutions poorer than 0.2% in the constant ΔE/E mode or poorer than 1.5 eV in the constant ΔE mode, to instruments requiring tolerance limits of ±0.05 eV or less or to instruments equipped with an electron gun that cannot be operated in the energy range 5–10 keV. This standard does not provide a full Calibration Check, which would confirm the energy measured at each addressable point on the energy scale and should be performed according to the manufacturer's recommended procedures. Crown Copyright © 2003. Published by John Wiley & Sons, Ltd.
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summary of iso tc 201 standard vii iso 15472 2001 surface chemical analysis x ray photoelectron spectrometers Calibration of energy scales
Surface and Interface Analysis, 2001Co-Authors: Martin P. SeahAbstract:This international standard specifies a method for calibrating the binding energy scales of x-ray photoelectron spectrometers, for general analytical purposes, using unmonochromated Al or Mg x-rays or monochromated Al x-rays. It is only applicable to instruments that have an ion gun for sputter cleaning. This international standard further specifies a method to establish a Calibration schedule, to test for the binding energy scale linearity at one intermediate energy, to confirm the uncertainty of the scale Calibration at one low and one high binding energy value, to correct for small drifts of that scale and to define the expanded uncertainty of the Calibration of the binding energy scale for a confidence level of 95%. This uncertainty includes contributions for behaviour observed in inter-laboratory studies but does not cover all of the defects that could occur. This international standard is not applicable to instruments with binding energy scale errors that are significantly non-linear with energy, to instruments operated in the constant retardation ratio mode at retardation ratios of <10, to instruments with a spectrometer resolution worse than 1.5 eV or to instruments requiring tolerance limits of ±0.03 eV or less. This international standard does not provide a full Calibration Check, which would confirm the energy measured at each addressable point on the energy scale and would have to be performed in accordance with the manufacturer's recommended procedures. © Crown Copyright 2001. Published by John Wiley & Sons, Ltd.
Robert A. Wise - One of the best experts on this subject based on the ideXlab platform.
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Spirometer Calibration Checks: Is 3.5% Good Enough?
Chest, 2007Co-Authors: Meredith C. Mccormack, David M. Shade, Robert A. WiseAbstract:Background Current standards for spirometry require daily Calibration Checks to come within 3.5% of the inserted volume but do not require evaluation of trends over time. We examined the current guidelines and candidate quality control rules to determine the best method for identifying spirometers with suboptimal performance. Methods Daily Calibration Checks on seven volume spirometers recorded over 4 to 11 years were reviewed. Current guidelines and candidate quality control rules were applied to determine how well each detected suboptimal spirometer performance. Results Overall, 98% of 7,497 Calibration Checks were within 3.5%. However, based on visual inspection of Calibration Check data plots, spirometers 3 and 5 demonstrated systematic sources of error, drift, and bias. The ± 3.5% criteria did not identify these spirometers. The application of ± 2% criteria identified these spirometers (9% out-of control values in spirometers 3 and 5 vs Conclusions The current recommendation that Calibration Checks come within ± 3.5% of the inserted volume did not detect subtle errors. Alternative candidate rules were more effective in detecting errors and maintained low overall error-detection rates. Our findings emphasize the need for laboratories to systematically review Calibration Checks over time and suggest that more stringent guidelines for Calibration Checks may be warranted for volume spirometers. Although our general approach may also be appropriate for flow-type spirometers, the details are likely to differ since flow-type spirometers are a much more varied category of equipment.
J.e.k. Schawe - One of the best experts on this subject based on the ideXlab platform.
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A new method to estimate transition temperatures and heats by peak form analysis
Thermochimica Acta, 1993Co-Authors: J.e.k. SchaweAbstract:Abstract A simple model of heat transfer within a dynamic calorimeter is introduced. On the basis of this model the measured signal of a known thermal event in the sample can be calculated. For this result a method is developed to estimate the true transition temperature and enthalpy from only one heating run. The method is valid on melting peaks with and without a stepwise change of heat capacity. The new method has been experimentally verified for different pure substances. This method can be used as a simple and fast Calibration Check for a differential scanning calorimeter.
Neeta Ray-chaudhuri - One of the best experts on this subject based on the ideXlab platform.
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Frequency of goldmann applanation tonometer Calibration error Checks.
Journal of glaucoma, 2005Co-Authors: Sukhpal S. Sandhu, Sandip Chattopadhyay, M.k. Birch, Neeta Ray-chaudhuriAbstract:Purpose To investigate how quickly Goldmann applanation tonometers used in clinical practice develop Calibration errors, and to determine the frequency of Checks required to detect these errors. Materials and methods Prospective Check of the Calibration error of all Haag-Streit Goldmann applanation tonometers in the department at month zero, month one, and month four. The tonometers were Checked according to the Haag-Streit method using a standard Calibration Check weight bar by two independent observers. Calibration errors were classed as +/-0.5 to 2.5 mm Hg, +/-3 to 4 mm Hg, or >+/-4 mm Hg. Tonometers with a Calibration error greater than +/-2.5 mm Hg were returned to the manufacturer for re-Calibration. Results At month zero 2 of 34 (5.9%), at month one 3 of 29 (10.3%), and at month four 0 of 33 (0.0%) tonometers fell within the manufacturer's recommended Calibration range of +/-0.5 mm Hg. A total of 14 of 34 (41.2%) tonometers at month zero, 10 of 29 (34.5%) tonometers at month one, and 17 of 33 (51.5%) tonometers at month four were identified to have Calibration errors greater than +/-2.5 mm Hg. Conclusions Goldmann applanation tonometers are not as accurate as the manufacturer's recommended Calibration error tolerance of +/-0.5 mm Hg would suggest. Calibration error of less than +/-2.5 mm Hg is clinically acceptable. Calibration error Checks should be carried out once monthly and tonometers with Calibration error greater than +/-2.5 mm Hg returned to the manufacturer for re-Calibration. Additional Checks should be made if tonometers suffer specific damage. Ideally individual ophthalmologists should Check Calibration before each session.
Meredith C. Mccormack - One of the best experts on this subject based on the ideXlab platform.
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Spirometer Calibration Checks: Is 3.5% Good Enough?
Chest, 2007Co-Authors: Meredith C. Mccormack, David M. Shade, Robert A. WiseAbstract:Background Current standards for spirometry require daily Calibration Checks to come within 3.5% of the inserted volume but do not require evaluation of trends over time. We examined the current guidelines and candidate quality control rules to determine the best method for identifying spirometers with suboptimal performance. Methods Daily Calibration Checks on seven volume spirometers recorded over 4 to 11 years were reviewed. Current guidelines and candidate quality control rules were applied to determine how well each detected suboptimal spirometer performance. Results Overall, 98% of 7,497 Calibration Checks were within 3.5%. However, based on visual inspection of Calibration Check data plots, spirometers 3 and 5 demonstrated systematic sources of error, drift, and bias. The ± 3.5% criteria did not identify these spirometers. The application of ± 2% criteria identified these spirometers (9% out-of control values in spirometers 3 and 5 vs Conclusions The current recommendation that Calibration Checks come within ± 3.5% of the inserted volume did not detect subtle errors. Alternative candidate rules were more effective in detecting errors and maintained low overall error-detection rates. Our findings emphasize the need for laboratories to systematically review Calibration Checks over time and suggest that more stringent guidelines for Calibration Checks may be warranted for volume spirometers. Although our general approach may also be appropriate for flow-type spirometers, the details are likely to differ since flow-type spirometers are a much more varied category of equipment.
