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Cited by 17Scientific Measurement and Uncertainty EvaluationCalibration and Measurement TechniquesSensor Technology and Measurement Systems

Review Article: Recommended practice for calibrating vacuum gauges of the ionization type

Open access
Fedchak, James A., Abbott, Patrick J., Hendricks, Jay H., Arnold, Paul C., Peacock, Neil T.·2018·Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films
DOI 10.1116/1.5025060PMC PMC6513016
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Abstract

This article represents a recommended practice for the calibration of ionization gauges usig the comparison method. In this method, ionization gauges are compared to a working standard that has a système international, or the international system of units traceable calibration. The ionization gauge is either of the hot-cathode ionization type or the cold-cathode ionization type. Details of the calibration apparatus, the principle of operation of the gauges, data analysis, uncertainty budget, and reporting the uncertainty are given.

AI snapshot

Written from the paper’s full text.

TL;DR

This AVS recommended practice describes comparison-method calibration of hot- and cold-cathode ionization gauges from 10−7 Pa to 1 Pa, including apparatus, procedure, data analysis, uncertainty, and reporting. It recommends working standards by pressure range and gives detailed practical guidance for traceable calibrations.

Key findings

  • Calibration scope is the comparison method only, over 10−7 Pa to 1 Pa; recommended working standards are capacitance diaphragm gauges above 10−2 Pa, spinning rotor gauges from 10−1 Pa to 10−4 Pa, and ionization gauges below 10−4 Pa.
  • System/environment recommendations include temperature stability of about 1 °C (±0.5 °C), base pressure at least 10× below the lowest calibration pressure (100× more ideal), and baking at 125–150 °C for a minimum of three days for base pressures below 10−6 Pa, with bake temperatures above 200 °C not recommended.
  • For HCIG operation, recommended emission currents are much less than 1 mA above 10−4 Pa and 4–10 mA below 10−5 Pa; typical degassing is 10 minutes at 40 W; HCIG temperature dependence is 0.3% per kelvin, with a recommended adjustment of 0.26% ± 0.02% per degree Celsius.
  • Data analysis defines a pressure-dependent correction factor fc = ΔPstd/ΔPUUT and an uncertainty uc = √(uB² + uA²), with Type B components including working-standard calibration, resolution, long-term stability, UUT resolution, pressure gradient, base pressure, and gas purity; calibration gas purity of at least 99.95% is recommended.

Methods

  • Design: developed by a subcommittee of the AVS Recommended Practice Committee, composed of vacuum gauge users and manufacturers; it is a recommended practice/review, not an experimental study.
  • Data or sample: draws on data from many sources and expert experience; no primary experimental sample or population is reported. It covers ionization gauge systems consisting of the pressure sensing element, operating electronics, and connecting cables.
  • Main analysis: provides procedures for comparison calibration against an SI-traceable working standard, defines correction factors, describes interpolation/adjustment to common pressure and temperature, gives a Type A/Type B uncertainty budget, and lists minimum calibration report contents.

Limitations

  • Stated: only the comparison method is covered; primary methods are excluded; scope is limited to 10−7 Pa to 1 Pa; compact gauges and combination/wide-range gauges are not specifically discussed; the reader is assumed to be familiar with basic ionization gauge operation and high-vacuum technology; calibrations are performed “as-is” with no internal adjustment of the instrument.
  • Stated/evident: the recommendations are based on expert consensus and literature rather than a systematic empirical validation, and no new experimental dataset or outcome study is reported.
  • Evident: the guidance may not apply outside the stated pressure range, gauge types, or to primary calibration methods.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1116/1.5025060

Cites

47 of 47 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

3 of 19 cited sources checked · 2 supported · 1 flagged · accuracy not yet measured

  • Premisecitation

    The gauge sensitivity strongly depends on the ionization probability of the calibration gas.

    “The gauge sensitivity strongly depends on the ionization probability of the calibration gas.”
    Quote in the paperSubstantial claim1 of 6 sources checked
    • cites [13] 1973, J. Vac. Sci. Technol. source
    • cites [14] 1969, Empirical observations on the sensitivity of hot cathode ionization type vacuum gages

      Not checked in the free run.

    • cites [15] 1975, Vacuum source
    • cites [16] 1974, Jpn. J. Appl. Phys., Part 1 source

      The Introduction (p. 2) says gauge sensitivity depends greatly on the nature of the gas, but does not attribute that dependence to ionization probability. In Results and Discussion (p. 5), the authors instead consider ionization probability to be nearly similar across gases and report that relative sensitivity increases linearly with molecular cross section. (LLM, conf=0.78)

      Checked by a reasoning model — may be wrong.

      Experimental — accuracy not yet measured
    • cites [17] 1983, Vacuum source
    • cites [18] 2013, Int. J. Mass Spectrom. source
  • Findingcitation

    A 1.0 % uncertainty in each electrode potential contributes about 0.25 % uncertainty in the ion current.

    “A 1.0 % uncertainty in each electrode potential, for example, contributes about 0.25 % uncertainty in the ion current.50”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [50] 2005, Results of performance dependencies of Bayard-Alpert type hot cathode ionization gauges upon operational parameters of their controllers

      Queued — the background check reaches it, usually within a day.

  • Premisereasoning

    Both chamber and gauge outgassing can be a problem in static systems because it causes a steady pressure rise.

    “Both chamber and gauge outgassing can be a problem in static systems because it causes a steady pressure rise.”
    Quote in the paperSubstantial claim
  • Premisecitation

    Gas desorbed from the gauge structure can cause large errors in pressure readings.

    “Gas desorbed from the gauge structure can cause large errors in pressure readings.9”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [9] 1993

      Not checked in the free run.

  • Interpretationreasoning

    The pressure rise from outgassing in a static system is a serious concern at low pressures and for chambers with small volumes.

    “This is a serious concern at low pressures and for chambers with small volumes.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim. 44
  • May combine two claims. 24
  • The quote only partly states this claim. 1

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Interpretationcitation

    The methods described are specific to HCIGs and CCIGs, but many of the considerations will be generally true even as new working standards and vacuum sensors are developed.

    “The methods described here are specific to HCIGs and CCIGs, but many of the considerations will be generally true even as new working standards and vacuum sensors are developed.56,57”
    Quote in the paperNot a substantial claim2 of 2 sources checked
    • cites [56] 2017, Metrologia source
    • cites [57] 2017, Metrologia source

  • Classified as probably not a substantial claim. May combine two claims.

    Interpretationreasoning

    An ionization gauge calibration is a property of the entire ionization gauge system (pressure sensing element, operating electronics, and connecting cables), so replacing any part of the system nullifies the calibration.

    “Ionization gauges must be calibrated as part of an ionization gauge system, which consists of the pressure sensing element, operating electronics, and any connecting cables. In general, any part of the system can affect the calibration, and so replacing part of the system nullifies the calibration. Hereafter, an ionization gauge calibration refers to the entire system.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S4 (based).

    Premisenone given

    The working standard for comparison calibration is a previously calibrated capacitance diaphragm gauge, spinning rotor gauge, or ionization gauge, depending on the pressure range.

    “The reference standard, or working standard, is a previously calibrated capacitance diaphragm gauge (CDG), spinning rotor gauge (SRG) or ionization gauge (IG), depending upon the pressure range over which the calibration will be performed.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Premisereasoning

    Extra components between the chamber and any ionization gauge can affect conductance and can outgas, causing locally high pressures.

    “Extra components can affect conductance and can outgas, causing locally high pressures.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Study design and conductreasoning

    HCIGs should be degassed prior to a calibration run.

    “HCIGs should be degassed prior to a calibration run.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationnone given

    Once calibrated at a specific gas sensitivity factor and gauge constant, the obtained calibration factor cannot be used for any other value of S or K.

    “Once calibrated at a specific gas sensitivity factor and gauge constant, the obtained calibration factor cannot be used for any other value of S or K.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Premisereasoning

    Pressure gradients can be a concern in the dynamic flow method.

    “Pressure gradients can be a concern in the dynamic flow method.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Interpretationreasoning

    Elastomer seals are acceptable for systems requiring base pressures above 1 × 10−6 Pa, but their use should be minimized to reduce outgassing and permeation, both of which will limit the ultimate pressure of the system.

    “Elastomer seals are acceptable for systems requiring base pressures above 1 × 10−6 Pa, but their use should be minimized to reduce outgassing and permeation, both of which will limit the ultimate pressure of the system.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S4 (based).

    Study design and conductnone given

    All data must be gathered under the same gauge operating parameters, e.g., emission current.

    “All data must be gathered under the same gauge operating parameters, e.g., emission current.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given

    The methods described are suitable for ionization gauges of either hot-cathode or cold-cathode type.

    “The methods described are suitable for ionization gauges of either hot or the cold cathode type.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisenone given

    Cryopumps offer high pumping speeds for most gases, but can only pump a finite amount of gas before regeneration is required.

    “Cryopumps offer high pumping speeds for most gases, but can only pump a finite amount of gas before regeneration is required.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Premisenone given

    The comparison method is suitable for calibrating ionization gauges over the pressure range 10−7 Pa to 1 Pa.

    “The only calibration method covered in this article is the comparison method, i.e., by comparison of the pressure reading (or another quantity that is a function of the pressure, such as ion current) from an ionization gauge under test to that of a reference standard gauge or working standard gauge within the pressure range of 10−7 Pa to 1 Pa.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Study design and conductreasoning

    The base pressure should be lower than the first calibration pressure by at least a factor of 10, but a factor of 100 is more ideal.

    “The base pressure should be lower than the first calibration pressure by at least a factor of 10, but a factor of 100 is more ideal.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Premisenone given

    The gauge calibration will depend on the emission current.

    “However, the gauge calibration will depend on the emission current, and so this will need to be set to the desired range before the calibration is begun.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Premisenone given

    RGAs usually require high-vacuum for operation; they cannot be used to detect gross leaks.

    “RGAs usually require high-vacuum for operation; they cannot be used to detect “gross” leaks.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    Higher emission currents reduce the gas desorbed on the filament and grid, thereby reducing the ESD effect.

    “Higher emission currents serve to reduce the gas desorbed on the filament and grid, thereby reducing the ESD effect.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisereasoning

    The relative gas sensitivity factor depends on the gauge geometry and applies only to the particular gauge from which it was determined.

    “However, the user is cautioned that the relative gas sensitivity factor also depends on the gauge geometry and applies only to the particular gauge from which they were determined.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Emission currents are usually increased at low pressure to increase the ion current at the collector and to reduce the effects of ions created by electron stimulated desorption (ESD).

    “Emission currents are usually increased at low pressure to increase the ion current at the collector and to reduce the effects of ion created by electron stimulated desorption (ESD).15”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [15] 1975, Vacuum source

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    Any short in the gauge electrodes will result in faulty operation.

    “A check that the individual electrodes are electrically isolated (i.e., at least 1010 Ω) from one another and from ground (chamber potential) should be made, as any short will result in faulty operation.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    The difference between fc(PUUT) and fc(ΔPUUT) is negligible for PUUT >> ΔPUUT, which is why it is important that the lowest calibration pressure be at least 10 times the base pressure.

    “The difference between fc(PUUT) and fc(ΔPUUT) is negligible for PUUT >> ΔPUUT, which is why it is important that the lowest calibration pressure be at least 10 times the base pressure.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Study design and conductnone given

    The pressure unit setting shall be recorded and used consistently throughout the calibration.

    “The pressure unit setting shall be recorded and used consistently throughout the calibration.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S4 (based).

    Premisereasoning

    ESD ions may result from the off-gassed products, causing a high pressure reading in the gauge.

    “in addition, it is possible that ESD ions result from the off-gassed products, also causing a high pressure reading in the gauge.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Study design and conductreasoning

    It is critical to record the relative gas sensitivity factor (and K, if settable) used during the calibration.

    “Note that it is critical to record the relative gas sensitivity factor (and K, if settable) used during the calibration.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given

    The static method is most useful at higher calibration pressures where outgassing does not significantly contribute to the pressure reading.

    “This method is most useful at higher calibration pressures where outgassing does not significantly contribute to the pressure reading.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationreasoning

    A bake of the calibration system to at least 100 °C is required to obtain the system base pressures required for calibrations below 1 × 10−6 Pa.

    “A bake of the calibration system to at least 100 °C is required to obtain the system base pressures required for calibrations below 1 × 10−6 Pa.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: Most vacuum systems cannot obtain pressures below the 10−6 Pa range within a few days of operation.

  • Classified as probably not a substantial claim. May combine two claims.

    Premisenone given

    Ion pump pumping speed is highly gas dependent and most do not pump noble gases well.

    “Their pumping speed is highly gas dependent and most do not pump noble gases well”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).

    Interpretationnone given

    The design and construction of the comparison apparatus, the consideration in the uncertainty budget, and attention to detail can be of general applicability to comparison calibrations.

    “The design and construction of the comparison apparatus, the consideration in the uncertainty budget, and attention to detail, for example, can be of general applicability to comparison calibrations.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S4 (based).

    Premisenone given

    Ionization gauges tend to outgas, which can cause a pressure rise within the gauge if the conductance is restricted.

    “Ionization gauges tend to outgas, which can cause a pressure rise within the gauge if the conductance is restricted.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Interpretationnone given

    Gauge tubes with visible contamination or excessively dirty internal electrodes are best replaced; the long-term stability of the sensitivity may be compromised.

    “Gauge tubes with visible contamination or excessively dirty internal electrodes are best replaced; the long-term stability of the sensitivity may be compromised.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Study design and conductnone given

    Calibration should not proceed until the requirements for stable base pressure are met; this can take 24 hours or more.

    “Calibration should not proceed until the requirements for stable base pressure are met; this can take 24 hours or more.”
    Quote in the paperNot a substantial claim

  • The quote only partly states this claim.

    Interpretationreasoning

    If fc is not constant, large errors in fc can result when the lowest calibration pressure is not at least 10 times the base pressure.

    “Otherwise, large errors in fc can result if fc is not constant.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Study design and conductnone given

    The calibration chamber temperature should be stable to within 1 °C for at least an hour.

    “The calibration chamber temperature should also be stable to within 1 °C for at least an hour.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S4 (based).

    Premisenone given

    Such bakes remove water and other condensable material from the surfaces within the vacuum system.

    “Such bakes remove water and other condensable material from the surfaces within the vacuum system.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Premisenone given

    An operating filament is much hotter than 150 °C and may produce significant off-gassing when ignited, even if it has been previously baked.

    “The main concern is that an operating filament is much hotter than 150 °C and may produce significant off-gassing when ignited, even if it has been previously baked.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisenone given

    Spherical chambers have the smallest area to volume ratio, but cylindrical chambers with a length that is equal to the diameter are a very close approximation.

    “Spherical chambers have the smallest area to volume ratio, but cylindrical chambers with a length that is equal to the diameter are a very close approximation.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Study design and conductnone given

    Ideally, a minimum of three approximately equal steps per pressure decade should be taken over the calibration range of interest.

    “Ideally, a minimum of three approximately equal steps per pressure decade should be taken over the calibration range of interest.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisenone given

    RGAs are useful for monitoring the test gas purity and performing leak detection.

    “Residual gas analyzers (RGAs), also known as quadrupole mass spectrometers, are useful for monitoring the test gas purity, and performing leak detection.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given

    Venting with clean gas reduces the amount of dust and other contaminants entering the vacuum system.

    “Furthermore, venting with clean gas reduces the amount of dust and other contaminants entering the vacuum system.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    Ionization gauges may be operated after the calibration system has been pumped down to a pressure below the maximum pressure of the gauge as given by the manufacturer, typically 10−2 Pa or lower.

    “Ionization gauges may be operated after the calibration system has been pumped down to a pressure below the maximum pressure of the gauge as given by the manufacturer, typically 10−2 Pa or lower.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    Modern controllers typically regulate electrode potentials to better than 1%.

    “Modern controllers typically regulate these potentials to better than 1%.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Interpretationreasoning

    Ion pumps can produce a low ultimate pressure, and can be used in combination with a throughput pump to produce a low ultimate pressure system with high throughput.

    “but they can produce a low ultimate pressure, and can be used in combination with a throughput pump to produce a low ultimate pressure system with high throughput.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    The difference between two successive decades often corresponds to a real change in scale, such as a different amplifier gain, and the correction factors may be discontinuous across scale changes.

    “This is because the difference between two successive decades often corresponds to a real change in scale, such as a different amplifier gain, and the correction factors may be discontinuous across scale changes.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Interpretationreasoning

    Even if the gauge has been baked, degassing is still necessary.

    “Even if the gauge has been baked, degassing is still necessary.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: During degassing, the temperature of the grid can reach 700 °C, which is much higher than typical chamber bake temperatures.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    The calibration will depend upon the filament that is used.

    “The calibration will depend upon the filament that is used.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    Dry pumps minimize hydrocarbon contamination as compared to oil-sealed pumps.

    “These will minimize hydrocarbon contamination as compared to, for example, oil-sealed pumps.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Interpretationreasoning

    Venting the system with N2 or Ar reduces the time that the vacuum chamber is exposed to ambient laboratory air and consequently water, thus minimizing water adsorption on the chamber walls and providing a faster turn-around time for the vacuum system.

    “Venting the system with N2 or Ar is recommended. This reduces the time that the vacuum chamber is exposed to ambient laboratory air and consequently water, thus minimizing water adsorption on the chamber walls and providing a faster “turn-around” time for the vacuum system.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning

    Capture pumps, such as ion pumps and some cryopumps, may not be suitable for pumping high gas throughput calibration chambers.

    “Caution is advised before using capture pumps, such as ion pumps and some cryopumps, as these may not be suitable for pumping high gas throughput calibration chambers.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Study design and conductnone given

    Several readings shall be taken (a minimum of 5 is recommended) and averaged.

    “Several readings shall be taken (we recommend a minimum of 5) and averaged.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisenone given

    Ion pumps do not, in general, have a constant pumping speed, which can complicate the operation of a dynamic expansion system.

    “Ion pumps do not, in general, have a constant pumping speed, which can complicate the operation of a dynamic expansion system.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Interpretationreasoning

    Dynamic flow chambers with ratios smaller than 1000 may also be used with success, but the uncertainty due to potential pressure gradients must be carefully characterized.

    “Dynamic flow chambers with ratios smaller than 1000 may also be used with success, but the uncertainty due to potential pressure gradients must be carefully characterized.”
    Quote in the paperSubstantial claim
50 of 50

  • The paper relies on this without support.

    The calibration uncertainty of ionization gauges will be several percent in most cases.

    “Because the calibration uncertainty of ionization gauges will be several percent in most cases”

  • The paper relies on this without support.

    Vibrations can potentially affect gauge performance.

    “Vibrations can potentially affect gauge performance.”

  • The paper relies on this without support.

    SRGs are particularly susceptible to vibration noise.

    “SRGs are particularly susceptible to vibration noise.”

  • The paper relies on this without support.

    Throughput-type pumps have high pumping speeds and can pump all gases without long-term changes in pumping speed.

    “These pumps have high pumping speeds and can pump all gases without long-term changes in pumping speed.”

  • The paper relies on this without support.

    Most vacuum systems cannot obtain pressures below the 10−6 Pa range within a few days of operation.

    “Most vacuum systems cannot obtain pressures below the 10−6 Pa range within a few days of operation.”

  • The paper relies on this without support.

    A ratio of 1000 or greater will effectively eliminate relevant pressure gradients.

    “A ratio of 1000 or greater will effectively eliminate relevant pressure gradients.”

  • The paper relies on this without support.

    Mass spectrometer signals in unbaked systems are typically dominated by relative molecular mass 18 (H2O); a dominant relative molecular mass 28 peak (N2 or CO) together with a relative molecular mass 32 peak (O2) is a strong indication of an air leak.

    “Mass spectrometer signals in unbaked systems are typically dominated by relative molecular mass 18 (H2O); a dominant relative molecular mass 28 peak (N2 or CO) together with a relative molecular mass 32 peak (O2) is a strong indication of an air leak.”

  • The paper relies on this without support.

    Baked systems should have a dominant H2 peak (relative molecular mass of 2), with very small or negligible signals at relative molecular masses 18 and 28.

    “Baked systems should have a dominant H2 peak (relative molecular mass of 2), with very small or negligible signals at relative molecular masses 18 and 28.”

  • The paper relies on this without support.

    RGA calibration highly depends on the various settings of the device.

    “Their calibration highly depends on the various settings of the device”

  • The paper relies on this without support.

    RGAs have poor long-term stability.

    “they have poor long-term stability”

  • The paper relies on this without support.

    RGAs can be highly non-linear.

    “and can be highly non-linear.”

  • The paper relies on this without support.

    The sensitivity and calibration factor of an ionization gauge depends upon the gas being measured.

    “Because the sensitivity and calibration factor of an ionization gauge depends upon the gas being measured”

  • The paper relies on this without support.

    If the system pumps are fully operational, most systems will realize the required pressure within the first hour of operation.

    “Otherwise, if the system pumps are fully operational (turbomolecular pumps at full speed or cryopumps at operational temperature, for example), most systems will realize this pressure within the first hour of operation.”

  • The paper relies on this without support.

    Typically, more than 24 hours of baking is required; higher temperatures allow shorter bake times.

    “Typically, more than 24 hours of baking is required; higher temperatures allow shorter bake times.”

  • The paper relies on this without support.

    Electrode potentials that are out of tolerance may indicate a problem with the controller or gauge.

    “Electrode potentials which are out of tolerance may indicate a problem with the controller or gauge, and it is best practice to repair or replace malfunctioning controllers.”

  • The paper relies on this without support.

    Shorting the electrode during a check can damage the controller.

    “However, shorting the electrode during such a check can damage the controller.”

  • The paper relies on this without support.

    Many controllers do not indicate the values of the electrode potentials, and the manufacturer may not give a procedure to measure these.

    “We also recognize that many controllers do not indicate the values of the electrode potentials, and the manufacturer may not give a procedure to measure these.”

  • The paper relies on this without support.

    HCIGs can be damaged by being degassed at too high a pressure.

    “HCIGs can be damaged by being degassed at too high a pressure.”

  • The paper relies on this without support.

    During degassing, the temperature of the grid can reach 700 °C, which is much higher than typical chamber bake temperatures.

    “During degassing, the temperature of the grid can reach 700 °C, which is much higher than typical chamber bake temperatures.”

  • The paper relies on this without support.

    For most unbaked calibration systems, the largest gas constituent at base pressure is water vapor.

    “For most unbaked calibration systems, the largest gas constituent at base pressure is water vapor, but the gauge relative sensitivity shall be set to that of the calibration gas.”

  • The paper relies on this without support.

    The operating potential of a cold-cathode gauge varies from manufacturer to manufacturer.

    “The operating potential varies from manufacturer to manufacturer, so it is necessary to consult them or their literature to find the nominal value.”

  • The authors state this as an assumption.

    Once the values of S and K are set in the controller, they are not changed.

    “Here we also assume that once the values of S and K are set in the controller, they are not changed.”
22 of 22

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Smaller orifice conflicts with stated minimum area ratio

    Minor

    The text recommends a sufficiently small conductance limiter to minimize pressure gradients, then says an orifice-to-chamber area ratio of at least 1000 eliminates them. Making the orifice smaller decreases that stated ratio, rather than increasing it.

  • Pressure-change comparison is reversed

    Minor

    The paper defines ΔPUUT as PUUT minus its base-pressure reading and requires the base pressure to be at least ten times lower than the first calibration pressure. Under those conditions PUUT and ΔPUUT are close; PUUT is not much greater than ΔPUUT as stated.

  • Gas-purity uncertainty is understated tenfold

    Minor

    If 1% of the gas has a relative sensitivity differing by 0.2, its contribution is 1% × 0.2 = 0.2%, not 0.02%. The subsequent estimate for an ionization-gauge working standard also inherits this error.

    Reported 0.02 · recomputed 0.2

3 of 3

Cites

Flagged first, then by citations

Research works printed but not linked: 8

  1. 2003, A User's Guide to Vacuum Technology
  2. 1993, Vacuum Sealing Techniques
  3. 1985, Total Pressure Measurements in Vacuum Technology
  4. JCGM 200:2012, 2012, The International Vocabulary of Metrology-Basic and General Concepts and Associated Terms (VIM)
  5. 1994, Guidelines for evaluating and expressing the uncertainty of nist measurement results
  6. 1993, The Physical Basis of Ultrahigh Vacuum, 304
  7. 1949, Scientific Foundations of Vacuum Techniques, 332
  8. 1949, Philips Tech. Rev., 11, 116

Cited by

Sorted by citations

Related

Authors
Fedchak, J. A., Abbott, P. J., Hendricks, J. H., Arnold, P. C., & Peacock, N. T.
Affiliations
  • National Institute of Standards and Technology (US)
  • MKS Instruments (United States) (US)
  • Pine Place Consulting, LLC , Broomfield, Colorado 80020
Corresponding author
Fedchak, James A.
ORCID
Venue
Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films
Publisher
American Vacuum Society
Published
2018-04-27
Volume
36
Issue
3
ISSN
  • 0734-2101 (ISSN-L)
  • 1520-8559
DOI
10.1116/1.5025060
PMC
PMC6513016
OpenAlex
W2800989170
Semantic Scholar
818fbb9410bb41a1cfb11d73057700a434dee27c
Cited by
17
References
46
Citations by year
2026: 6 · 2025: 1 · 2024: 2 · 2023: 1 · 2022: 3 · 2021: 3 · 2018: 1
FWCI
0.76
Type
journal article
Language
en
Open access
Licence
Locations
  • Journal of Vacuum Science & Technology A Vacuum Surfaces and Films (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • PubMed Central (acceptedVersion)
Topics
  • Social Sciences › Decision Sciences › Statistics, Probability and Uncertainty › Scientific Measurement and Uncertainty Evaluation
  • Physical Sciences › Engineering › Aerospace Engineering › Calibration and Measurement Techniques
  • Physical Sciences › Computer Science › Computer Networks and Communications › Sensor Technology and Measurement Systems
Keywords
ionization gauge, vacuum gauge calibration, comparison method, hot cathode ionization gauge, measurement uncertainty, uncertainty budget, calibration apparatus

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-11-06.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-11-06.

Cited sources are checked by gpt-6-sol.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

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