Primary vacuum measurements for the traceability of the reference standards are performed through “Multi Stage Static Expansion System” (MSSE1) at TÜBİTAK UME Vacuum Laboratory (Figure 1). Pressure range is between 9 x 10-4 Pa and 103 Pa, with the relative uncertainty 2.1 x 10-3 – 9.5 x 10-4.
Figure 1 Multi-Stage Static Expansion System
Vacuum gauge calibrations needed by industry are performed through “Vacuum Gauge Metrology System” (VGMS). The system is given in Figure 2. Relative uncertainty range for the calibrations between 1 x 10-4 Pa and 1.33 x 105 Pa is 8.3 x 10-2 Pa -7.9 x 10-3 Pa. 
Figure 2 Vacuum Gauge Metrology System (VGMS)
Calibration measurement capability:
- Pirani, thermal conductivity and thermocouple vacuum gauges,
- Capacitance Diaphragm Manometers (CDG),
- Hot and cold cathode ionization vacuum gauges,
- Spinning Rotor Gauges (SRG),
- Full range vacuum gauges,
- Permeation type helium leak artefact (in vacuum)
TÜBİTAK UME Vacuum Laboratory has been accredited in 2005 by TÜRKAK (Turkish Accreditation Agency) in the following scope:
Table 1. Acreditation scope
|
Calibration scope and calibrated gauges |
Measurement Range |
Best Measurement Capability (Expressed as an expanded uncertainty) (k=2), p in pascal |
|
Absolute Pressure / Pa / Pirani and Thermocouple vacuum gauges |
1 x 10-1 Pa – 1 x 105 Pa |
4,1 x 10-2 x p –2,0 x 10-2 x p |
|
Absolute Pressure / Pa / Capacitance Diaphragm Manometers CDG) |
1 x 10-1 Pa – 1 x 105 Pa |
3,5 x 10-2 x p – 7,9 x 10-3 x p |
|
Absolute Pressure / Pa / Hot and Cold Cathode Ionisation vacuum gauges |
1 x 10-4 Pa – 1 x 10-1 Pa |
1,1 x 10-1 x p – 4,0 x 10-2 x p |
|
Absolute Pressure / Pa / Spinning Rotor Gauges (SRG) |
1 x 10-4 Pa – 1 x 10-1 Pa |
9,0 x 10-2 x p – 3,5 x 10-2 x p |
Within the scope of the EMRP IND12 "Vacuum metrology for production enviroments" European metrology research project, helium leakage standards and MSLD (Mass Spectrometer Leak Detector) stability measurements has been conducted. Besides, for quadrupole mass spectrometry (QMS) that is type of a RGA (Residual Gas Analyzer), the laboratory has been leaded the studies on time stability measurements and contributed investigation of the effects of device usage parameters on the device sensitivity. Quadrupole mass spectrometer stability studies has been performed on the dynamic vacuum system (Figure 3).
Figure 3 Dynamic Vacuum System
In order to determine the gas flow rates, the calibrations of helium leak standards are performed by comparison method using reference leak standards and commercial helium leak detector (Figure 4).
Figure 4 Calibration apparatus for helium leak standards
For primary gas flow rate measurements in vacuum, performance analysis and characterization studies of the Constant Pressure Gas Flowmeter(CPFM) system at very low gas flows are underway (targeted measuring range is between 4 x 10-12 mol/s and 4 x 10-7 mol/s).