No Title Leading NMI Country
WP1 Dynamic vacuum calibration facility PTB Germany
WP2 Leak measurement and testing INRIM Italy
WP3 Partial pressure and outgassing rate measurement MIRS-IMT Slovenia

Description of work packages

This work package addressed the objective "dynamic vacuum calibration facility" and the industrial need for the measurement of dynamic vacuum pressures.
The aim of this workpackage was to provide a calibration facility for vacuum gauges and fast downwards pressure changes from 100 kPa to 100 Pa within 1 s. The aim was to realise pressures in the facility which are predictable over periods of at least 10 ms with an uncertainty of 50 %. The readings of the vacuum gauge to be tested were compared with the predicted pressures p(t) at time t.
The calibration facility was designed such that it is also possible to generate fast upward pressure changes from 100 Pa to 90 kPa within 1 s. Results of optical methods for pressure measurement were compared to the pressures predicted by simulations.

This work package addressed the objective "improvement of leak measurement and testing in industrial environment". The aim of the workpackage was to improve the knowledge of gas flow through nano/microchannels in terms of predictability for different gas species and environmental conditions with the focus on the industrial applications and conditions.
In task 2.1 leak capillaries (for flow rates between 10-8 Pa m³/s and 10-4 Pa m³/s) were realised with a well-known geometry and calibrated using various gases against primary systems developed in each NMI. The gas species have been chosen both for their significance on the climate (green house gases and their substitutes) and their relevance for modelling the flow. Narrow ducts gas flow theory were improved in task 2.2 in order to increase the accuracy of the conversion function from helium gas flow to the flow of other gases and gas mixtures. The validity of these results was checked using capillaries manufactured and characterised in task 2.1. In task 2.3 the metrological characteristics of the leak artefacts such as temperature coefficient, gas flow rate stability, influence of changing atmospheric pressure on gas flow rate will be studied under industrial conditions. The linearity, repeatability, calibration curve and uncertainty evaluation of helium and refrigerant leak detectors fitted in a production line were evaluated and a Good Practice Guide was developed in task 2.4. Finally an alternative method to detect leaks was explored in task 2.5 using an optical method as a faster alternative to mass spectrometer detection.

This workpackage addressed the "Traceability for partial pressure measurement and outgassing rate measurement and materials characterisation in industry".
The aim of this workpackage was to develop dedicated calibration facilities for quadrupole mass spectrometers (QMS) and to investigate factors influencing metrological characteristics of QMS. The influence of operational parameters (electron and ion energy, mass resolution ...) on sensitivity and cracking patterns for different gases will be studied and a set of reference conditions to compare performance of instruments from different manufacturers established. As a first step we focussed on QMS with open ion sources and mass range from 0 amu to 100 or 200 amu, which are the most common instruments for residual gas analysis in vacuum systems and for analysis of outgassing species of vacuum materials, but will also include a QMS for process gases. Traceability and uncertainties of methods for "in-situ" calibrations of QMS on industrial vacuum systems will also be evaluated.
Another aim was to develop model systems for outgassing rate measurements applying different methods, to compare them, and provide measurement traceability of these methods. Currently there are no "certified reference materials" for outgassing rate available. Materials which exhibit reversible absorption of different gases could potentially be used for such purpose. We investigated the suitability of different materials as reference outgassing material.