ISO TS 20177 Procedures to measure and report outgassing rates

EMPIR 14SIP01 Workshop – Dr. Karl Jousten, PTB, Vacuum Metrology 1 Jan 30 to Feb 1, 2017

ISO TS 20177 Procedures to measure and

report outgassing rates

Introduction

1. Purpose and scope

2. Structure of content

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ISO TS 20177 (WD)

EMPIR 14SIP01 Workshop – Dr. Karl Jousten, PTB, Vacuum Metrology Jan 30 to Feb 1, 2017

qout ≤ 1·10-5 Pa m³/s (-> discussion later) Total outgassing rate and species outgassing rate For total outgassing rate: concept of nitrogen equivalent (-> discussion later) No direct line of sights required (-> discussion later) Methods described in TS shall be comparable Traceability a must for each method Relatively high uncertainties acceptable (more than 10% o.k.)

Scope/suppositions

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ISO TS 20177 (WD)


Structure of Content

1. Scope2. Normative references3. Terms and definitions4. Symbols and abbreviated terms

Obligatory from ISO template

9. References10. Appendix

5. Measurement systems6. Measurement procedures7. Measurement uncertainties8. Reporting results

Flexible

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ISO TS 20177 (WD)


5. Measurement systems

1. General recommendations for systems, chambers and pumps, gauges)

1. Recommendations for systems2. Chambers and pumps3. Vacuum gauges

2. Systems applying the throughput method

1. Continuous expansion system as flow comparator2. Throughput system with calulated conductance element

(one and two path design) 3. Throughput system with measured effective pumping speed4. Throughput system with modulated conductance

3. Accumulation systems

1. Basic accumulation system2. Accumulation system with gas analysis

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ISO TS 20177 (WD)


6. Measurement procedures

1. Recommended sample preparation 2. Course and time period of measurement3. Particular measurement procedures

1. Procedure with continuous expansion system as flow comparator

2. Procedure with throughput system with calulated conductance element

3. Procedure with throughput system with measured effective pumping speed

4. Procedure with throughput system with modulated conductance

5. Procedure with accumulation systems

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ISO TS 20177 (WD)


6. Measurement uncertainties

• Continuous expansion system as flow comparator• Throughput system with calulated conductance element • Throughput system with measured effective pumping speed• Throughput system with modulated conductance• Basic accumulation system• Accumulation system with gas analysis

Editorial: Numbering requested?

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ISO TS 20177 (WD)


Measurement uncertainties: List

Method Uncertainty contribution to be

considered

5.2.1 Continuous expansion system

as flow comparator

throughput (flow in) qpV,i

temperature T

5.2.2 Throughput system with

calculated conductance element (one

and two path design)

measured pressure p1 by gauge

(uncertainty in calibration certificate,

long-term instability, non-linearity,

correction factor for other species than

nitrogen)

estimated or measured (by gauge)

pressure p2 (one path design only)

conductance C

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ISO TS 20177 (WD)




considered


measured effective pumping speed

flow from standard leakpossible change of CN2 due to unknown change with pressuremeasured pressure p1 by gauge (uncertainty in calibration certificate, long-term instability, non-linearity, correction factor for other species than nitrogen)measured pressure p0 by gaugePosition of gauge or QMSQMS sensitivities

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ISO TS 20177 (WD)




considered


modulated conductance

measurement with vacuum gauge

(uncertainty in calibration certificate,

long-term instability, non-linearity,

correction factor for other species than

nitrogen)

conductances

incomplete equilibrium

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ISO TS 20177 (WD)



Method Uncertainty contribution to be considered

5.3.1 Basic accumulation system accumulation chamber and sample volume V

temperature T

pressure of accumulating gas p

time interval Δt

5.3.2 Accumulation system with

gas analysis system

accumulation chamber and sample volume V,

temperature T

pressure of accumulating gas p

time interval Δt

volume of optional chamber for calibration

gas V

pressure of calibration gas p

nonlinearity of the QMS

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ISO TS 20177 (WD)


5.2.1 Continuous expansion system as flow comparator1 measurement chamber 2 pump chamber 3 by-pass (recommended) 4 sample chamber 5 load-lock 6 sample 7 QMS 8 total pressure gauge 9 pump systems 10 reservoir 11 CDG 12 connection to gas supply

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ISO TS 20177 (WD)


5.2.2 Throughput system

with calculated

conductance (one-path

design)

1 measurement chamber 2

pump chamber 3 vacuum

gauge and QMS (optionally)

4,10 valves 5 by-pass

(optionally) 6 sample 7

sample chamber 8 load lock

9 pump systems

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ISO TS 20177 (WD)


5.2.2 Throughput system

with calculated

conductance (two-path

design)

1 measurement chamber 2

pump chamber 3,4 vacuum

gauge and QMS (optionally)

5 by-pass 6 sample 7 sample

chamber 8 load lock 9 pump

systems 10 second path line

B 11 valve for path A

(upstream), 12 valve for path

B (downstream)

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ISO TS 20177 (WD)


5.2.3 Throughput system with measured

effective pumping speed

1 measurement chamber 2 standard leak 3

vacuum gauge and QMS (optionally) 4 pump

systems 5 sample chamber 6 sample 7 load

lock

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ISO TS 20177 (WD)


5.2.4 Throughput system with modulated conductance

1 measurement chamber 2 element with first conductance and

holder 3 element with second conductance 4 vacuum gauge and

QMS (optionally) 5 linear feedthrough 6 pump systems 7 sample 8

sample chamber 9 load lock

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ISO TS 20177 (WD)


5.3.1 Basic accumulation system

1 measurement chamber of known volume 2 inert vacuum gauge

3 time measurement 4 pump systems 5 load lock 6 sample

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ISO TS 20177 (WD)


5.3.2 Accumulation system

with gas analysis system

1 measurement chamber of

known volume 2 inert vacuum

gauges 3 time measurement 4

pump systems 5 load lock 6

sample 7 QMS 8 Ionization

vacuum gauge 9 volume for

calibration gas (may also be

connected to chamber 1) 10 to

gas reservoir

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ISO TS 20177 (WD)


System Vapour

outgassing

Outgassing

is time

dependent

Identifies

species

Outgassing

rate > 10-9 Pa

m³ s-1

Outgassing

rate 10-9 Pa

m³ s-1

Accuracy Effort,

Experience

Sample is

chamber

5.2.1 Continuous

expansion system as

flow comparator

+ ++ ++ + - ++ Very high +

5.2.2 Throughput

system with

calculated

conductance element

(one path design)

+ ++ ++ + + + high +

5.2.2 Throughput

system with

calculated

conductance element

(two path design)

+ - ++ + ++ + high +

5.2.3 Throughput

system with

measured effective

pumping speed

+ ++ - + - -- low +

5.2.4 Throughput

system with

modulated

conductance

- - ++ + ++ + high +

5.3.1 Basic

accumulation system

-- - -- + ++ + low ++

5.2.3 Accumulation

system with gas

analysis system

-- - + + ++ + high +

Table 3 — Applicability and characteristic of the different measurement systems. It means: ++ well suited, + suitable, - less suitable , --- not suitable

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ISO TS 20177 (WD)


Method Traceable quantity Unit Traceable device Note

5.2.1 Continuous expansion system as flow comparator

C m³ s-1 = 10³ L s-1

One or several conductance elements

Specific for gas species

pi Pa

Vacuum gauge for medium and rough vacuum, preferentially with gas independent indication

Pressure of gas species i in reservoir, measured by secondary standard

5.2.2 Throughput system with calculated conductance element (one and two path design)

C m³ s-1 = 10³ L s-1 Orifice or short duct Specific for gas

species

p PaVacuum gauge for high and ultrahigh vacuum

Calibrated for nitrogen

pi Pa Quadrupol mass spectrometer

Optional, sensitivity for gas species i , stability check by sensitivity nitrogen

Table 4 — Quantities, by which traceability of outgassing rate (either total or partial) to the SI is established in the different measurement systems

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ISO TS 20177 (WD)



5.2.3 Throughput system with measured effective pumping speed

qpV Pa m³ s-1 Nitrogen standard leak To determine Ceff



qpV,i Pa m³ s-1 Standard leak for gas species i

Option, if QMS is used, to determine Ceff,i

5.2.4 Throughput system with modulated conductance

C m³ s-1 = 10³ L s-1

Two orifices or short ducts

Specific for gas species



pi Pa Quadrupol mass spectrometer

Optional, sensitivity for gas species i , stability check by sensitivity nitrogen

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ISO TS 20177 (WD)



5.3.1 Basic accumulation system

V m³ Chamber volume

p PaVacuum gauge for high and medium vacuum


t s clock

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ISO TS 20177 (WD)



5.2.3 Accumulation system with gas analysis system

V m³ Chamber volume

p PaVacuum gauge for high and medium vacuum


t s clock

pi Pa Quadrupole mass spectrometer

Sensitivity for gas species i

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ISO TS 20177 Procedures to measure and report outgassing rates

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