1. 1 International Standardization for QMS 1. Introduction: The procedure of standardization 2. What we do and do not intend with QMS standardization 3. Content of the new ISO 14291 4. Future work The work of ISO TC 112 towards international standards for specifications and calibration of quadrupole mass spectrometers Karl Jousten, PTB, Berlin

2. 2 Introduction Secretary TC 112: DIN VDMA, Frankfurt ISO Technical committee 112 Vacuum technology Chair: GER, F. Justen China, France, Germany, Italy, Japan, Korea, Russia, Spain, Switzerland, UK, USA plus 17 observers WG 1 Vacuum pumps Chair: UK, St. Omrod WG 2 Vacuum instrumentation Chair: GER, K. Jousten WG 3 Vacuum hardware Chair: J, M. Hirata International Standardization for QMS

3. 3 The procedure of standardization New work item proposal WD (working draft) CD (committee draft) DIS (Draft international standard) FDIS (Final draft international standard) International Standard 2 – 4 years Technical Specification International Standardization for QMS

4. 4 Standardization vacuum metrology International Standardization for Vacuum WG 2 Vacuum instrumentation Strategy: Make the dissemination of the pressure scale in vacuum more robust and more accurate by: Establishing the physics and engineering of comparison standards Specifying all parameters needed to calibrate and use a vacuum gauge and a QMS: 1)define the necessary physical quantities for the instruments, 2)let the manufacturers specify all important parameters for a calibration, 3)define calibration procedure, 4)give guideline for measurement uncertainty

5. 5 Standardization QMS International Standardization for Vacuum What we do not intend with standards for QMS: Pretend that a QMS can be calibrated in all its features Make an attempt to qualify a QMS as secondary standard Try to guidelining a user for interpreting complex spectra What we do intend with standards for QMS: Make different QMS for a user comparable (when buying) Establish a calibration procedure valuable for those users interested in accuracy and reproducibility Give traceability to SI for a selected, but relevant, application Guideline for proper use of QMS and its limitations

6. 6 ISO/DIS 14291 Specs for QMS International Standardization for Vacuum ISO/DIS 14291 Vacuum gauges – Definitions and specifications for quadrupole mass spectrometers Status: DIS accepted since 2012-01-11 after voting (100% approval). Content: Terms and Definitions Principle of QMS Specifications for QMS to be provided by manufacturers Optional specifications for QMS to be provided by manufacturers Scope: m/z < 300, electron impact ionization

7. 7 ISO/DIS 14291 Specs for QMS International Standardization for Vacuum Terms and Definitions: QMS definition kept from ISO 3529/3 Additionally defined (hardware): Sensor head, ion source (open, closed, molecular beam), mass filter, ion detector (Faraday, SEM, discrete dynode, CEM, MCP), electronic unit.

8. 8 ISO/DIS 14291 Specs for QMS International Standardization for Vacuum Physical parameters: Sensitivity (M* for N 2 ): p partial pressure, p 0 residual pressure (needs not to be known!). As AVS recommendation, but different from sensitivity of ion gauge! O*: Temperature coefficient of S Relative sensitivity factor: *M Mandatory spec *O Optional spec in ISO 14291

9. 9 ISO/DIS 14291 Specs for QMS International Standardization for Vacuum Mass resolution: Difference on m/z scale for x% valley between neighbored peaks of equal height (0.5x% height isolated peak). 10% valley, 5% peak height IUPAC gold book, ISO 14291 (M) Alternatives: 20% valley, 10% peak height: easier to measure against noise (AVS recommendation) FWHM (50% peak height), IUPAC recommendation, ISO 14291 (O)

10. 10 ISO/DIS 14291 Specs for QMS International Standardization for Vacuum Mass resolving power: Mass number stability:M for He or Ar (Discussed: N 2 ) Minimum detectable partial pressure: M for He, O for Ar(AVS : One sigma!) Discussed: N 2 Minumum detectable concentration: M for one selected mixture, recommended for He, Ar or Kr in air Fragmentation factor: O for water, methane, nitrogen, carbon monoxide

11. 11 ISO/DIS 14291 Specs for QMS International Standardization for Vacuum Non-linearity:  S in a certain pressure range Linear response range (M): partial pressure range where  S < given value Stability of peak height (peak intensity): at constant partial pressure (AVS: Drift) Intentionally we did not (yet) define (out of scope): tailing contribution (too much of work for manufacturers), mass discrimination (ion transmission vs m/z), incremental sensitivity (sensitivity at a certain operating pressure/mixture)

12. 12 ISO/DIS 14291 Specs for QMS International Standardization for Vacuum List of mandatory specs (32) for manufacturers: Mass range Type of ion source Mass resolution Mass number stability Sensitivity Linear response range Min detectable pressure Min detectable concentration Max operational pressure Scanning parameters Signal output (I, p) Potentials Detector specs Set points available Max bake-out temperature Operating conditions Warm-up time Electron emission current Filament exchange Detector exchange Fitting to chamber Mounting orientation Dimensions Internal volume Weight of sensor head and elec. unit Input power Cable Software Interfaces Storage and transportation conditions

13. 13 ISO/DIS 14291 Specs for QMS International Standardization for Vacuum List of optional specs (9) for manufacturers: Mass resolution (FWHM) Some typical fragmentation patterns Temperature coefficient of sensitivity QMS sensor cleaning Degassing Degassing power Photographs Inspection record Outgassing rate

14. 14 Standardization vacuum metrology International Standardization for Vacuum Additional future work Collect items for improvements for ISO 14291 Collect results from recent investigations on QMS characteristics and calibrations and draw conclusions (Under which conditions a QMS calibration is useful? What kind of calibration brings value for the user? Which conditions are robust and easy to provide?) Draft a technical specification to calibrate QMS Long term: Uncertainties associated with QMS calibration and measurements

15. 15 Standardization vacuum metrology International Standardization for Vacuum Discussion