Preparation Primary Gas Reference Material (PGRM) by using NIMT Facilities

Transcription

1 Preparation Primary Gas Reference Material (PGRM) by using NIMT Facilities By Ms.Ratirat Sinweeruthai June 9-11, 2010 Tsukuba, Japan 8 th APMP/TCQM Gas CRM Workshop

2 Overview Objective of Study EMU of Weighing Verification of PGRM Development of NIMT Facilities

3 Objective NIMT would like to establish the measurement unit in field of amount of substance in parameter of O 2 in N 2 find the method for preparation PGRM develop a system of preparation to be in line with a target uncertainty of NIMT

4 ( ) ( ) ( ) ( ) = = = = = ia p A n i ia i A p A A i i n i i i i x u x x m u m x M u M x x u Uncertainty of PGRM Where u(m i ) : Uncertainty in the Molar Mass u(m A ) : Uncertainty on the Weighings u(x ia ) : Uncertainty in the Purity Analysis (1)

5 Uncertainty on the weighing ( ) ( ) ( ) ( ) = = m u m x m u m x m u m x m u m x i i i A p A A i Where u(m 1 ) : Uncertainty on the First Weighings u(m 2 ) : Uncertainty on the Second Weighings u(m 3 ) : Uncertainty on the Third Weighings i : Component (2)

6 Weighing Method Ref.: A.Alink (VSL), et al, Metrologia 37, 2000 The equation of weighing a reference cylinder m c + ρ e. p Vc. ρ air = mr + W VR. ρair W. ρ air s (3) The equation of weighing a sample cylinder m c + e. q V c ρ air = m s + M V s ρ air M ρ ρ air s (4)

7 w j The basic equation of the difference between sample and reference cylinder. ρair, j = e j ( q j p j ) + ( W j M j )(1 ) + ρair, j ( Vs, ρ Where m c m R m s W M e p q V c V R V s ρ air ρ s mass of comparator mass of reference cylinder mass of sample cylinder total mass of mass pieces added to reference cylinder total mass of mass pieces added to sample cylinder calibration factor reading reference cylinder reading sample cylinder volume of contra mass volume of reference cylinder volume of sample cylinder density of air density of mass pieces s j V Ref.: A.Alink (VSL), et al, Metrologia 37, 2000 R (5) )

8 Weighing process within a weighing cycle. Weighing No. Weighing Step 0 R+W+Q 1 R+W 2 S+M 3 R+W 4 S+M 5 R+W 6 S+M 7 R+W 8 R+W+Q Q is calibration mass pieces Ref.: A.Alink (VSL), et al, Metrologia 37, 2000

9 Weighing No. Weighing Step Reading 0 R+W+Q m C,0 1 R+W m C,1 2 S+M m C,2 e j = ( m m + m m ) C,0 2m C,1 Q C,8 C,7 3 R+W m C,3 4 S+M m C,4 3 1 ϕ = 2 m 6 i= 1 C, 2i ( mc,1 + mc,7) 2( mc,3 + mc,5) 5 R+W m C,5 6 S+M m C,6 7 R+W m C,7 8 R+W+Q m C,8 Ref.: A.Alink (VSL), et al, Metrologia 37, 2000

10 Sources of Uncertainty on the weighing Balance (Weighing) A. Alink et.al., Uncertainty calculations for the preparation of primary gas mixture, Metrologia, 2000 Matsumoto et, al., Development of mass measurement equipment using an electronic mass-comparator for gravimetric preparation of reference gas mixtures, Metrologia, 2004 ISO 6142 Weights Standard Weights E2 are traceable to NIMT Buoyancy effect Based on ISO 6142 Measuring Instruments are traceable to NIMT Expansion of the cylinder Based on ISO 6142 Residual gas Based on ISO 6142

11 Uncertainty of Balance Balance Resolution Drift Incorrect zero point Effect of location of the cylinder on pan Etc. The pool estimate of standard uncertainty is a method to be selected for estimation uncertainty of a balance.

12 Pooled Estimate of Standard Deviation (S p ) Measurement ABBA Measurement QABABABAQ No. Δm (g) SD (mg) No. Δm (g) SD (mg) Sp Sp 2.83

13 Uncertainty Budget of Weighing Uncertainty contributions for vacuum Source Value (g) Standard Uncertainty Distribution Sensitivity Uncertainty contribution Standard Weights mg Normal mg Balance mg Normal mg Calibration factor (e j ) mg Normal mg Difference of reading balance (ϕ ) mg Normal mg Buoyancy effect mg Normal mg m x mg

14 Uncertainty contributions for first component Source Value (g) Standard Uncertainty Distribution Sensitivity Uncertainty Contribution Standard Weights mg Normal mg Balance mg Normal mg Calibration factor (e j ) mg Normal mg Difference of reading balance (ϕ ) mg Normal mg Buoyancy effect mg Normal mg m x mg

15 Uncertainty contributions for second component Source Value (g) Standard Uncertainty Distribution Sensitivity Uncertainty Contribution Standard Weights mg Normal mg Balance mg Normal mg Calibration factor (e j ) mg Normal mg Difference of reading balance (ϕ ) mg Normal mg Buoyancy effect mg Normal mg Expansion of cylinder mg Rectangular mg Residual gas mg Rectangular mg m x mg

16 Verification of PGRM Paramagnetic Oxygen Analyzer GC-TCD Column : Molecular sieve 5 meter Condition Sample flow rate 30 ml/min Oven temperature 30 o C Detector temperature 200 o C Loop volume 1 ml

17 Measurement of Goodness-of-fit ( Γ ) The coefficient parameters of the linear analytical function were calculated by using B_Least software.(iso6143) Γ = max xˆ i u x i ( x ) i And Γ = max ŷ i u y i ( y ) i The goodness-of-fit must be Γ 2

18 Paramagnetic Oxygen Analyzer Model: 4100 Range: 0 100% Resolution: 0.001% Repeatability: <0.01% for O 2 content Manufacturer: Servomex

19 Verification of PGRM by using Paramagnetic Oxygen Analyzer Mole Fraction (mol/mol) Gravimetric Result u(x), k=2 (µmol/mol) Mole Fraction (mol/mol) Analysis Result u(y), k=2 (µmol/mol) % Error Goodness-of-fit Verification them same as analysis technique of APMP-QM.S2 : O 2 /N 2

20 Verification of PGRM by using Paramagnetic Oxygen Analyzer Mole Fraction (mol/mol) Gravimetric Result u(x), k=2 (µmol/mol) Mole Fraction (mol/mol) Analysis Result u(y), k=2 (µmol/mol) % Error Goodness-of-fit Compatibility Criterion The standard uncertainty of gravimetric results is considered at 0.2% relative. The compatibility criterion used is: grav anal ( x ) 2 u( x ) 2 x x + 2 u grav anal

21 Verification of PGRM by using Paramagnetic Oxygen Analyzer Mole Fraction (mol/mol) Gravimetric Result u(x), k=2 (µmol/mol) Mole Fraction (mol/mol) Analysis Result u(y), k=2 (µmol/mol) % Error Goodness-of-fit Compatibility Criterion The compatibility criterion used is: grav anal ( x ) 2 u( x ) 2 x x + 2 u grav anal

22 Analysis Technique y q,1 y p,1 y q,2 y p,2 y q,3 y p,3 y q,4 QC cylinder PGRM 1 QC cylinder PGRM 2 QC cylinder PGRM 3 QC cylinder y i = y q, i 2. y + p, i y q, i+ 1 Where y i is the corrected response Ref.: M.J.T Milton, et al, Metrologia 43, 2006

23 Verification of PGRM by using GC-TCD Mole Fraction (mol/mol) Gravimetric Result u(x), k=2 (µmol/mol) Analysis Result by Area response y i u(y), k=2 Goodness-of-fit Mole Fraction (mol/mol) Gravimetric Result u(x), k=2 (µmol/mol) Analysis Result by Height response y i u(y), k=2 Goodness-of-fit

24 Problems from Original System Filling System Precision of weighing Ventilation Weighing System The weighing value is rather a fluctuation

25 Sources of Filling Error Target mole fraction Prepared mole fraction % Error air condition system Balance Filling system Experience

26 Original Filling System

27 Modified Filling System

28 Original Weighing System Ref.:Nobuhiro Matsumoto et al, Metrologia 41, 2004

29 Specification of Balance Model: KA 10-3 Readability: 2 mg Maximum load: 15 kg Repeatability: 6 mg Linearity: ± 0.2 g

30 Temperature Chart in Single Chamber

31 Temperature Chart in Single Chamber

32 Modified Weighing System

33 Temperature Chart in Double Chamber

34 Pooled Estimate of Standard Deviation (S p ) Measurement No. QABABABAQ SD (mg) Single Double Sp Decrease 64 %

35 Pooled Estimate of Standard Deviation (S p ) Measurement No. ABBA SD (mg) No Single Double Sp

36 First Weighing System Original System SD > 7.5 mg u(x) WB > 17 mg u(x) > 12 ppm Modified System SD < 3 mg u(x) WB < 14 mg u(x) < 7 ppm Reduced uncertainty 70%

37 Secondary Weighing System

38 Specification of Mass Comparator Model Readability Maximum load Repeatability Linearity XP26003L 1 mg 26 kg 3 mg 25 mg

39 Room Temperature Chart in Chamber of Second Weighing System

40 Acknowledgement National Metrology Institute of Japan (NMIJ) Dutch Metrology Institute (VSL) National Institute of Metrology (Thailand),(NIMT)

41 Thank you for your attention