CCTK4, EUROMET.TK4, EURAMET.TK3.3, APMP.TK4 and EURAMET.TK3.5
MEASURAND : Freezingpoint temperature of Aluminium (Al) fixedpoint cells
NOMINAL TEMPERATURE : 660.323 °C
Degrees of equivalence D_{i }and expanded uncertainty U_{i }(95% level of confidence) expressed in mK
Click on the graph for a closer view
CCTK4, EUROMET.TK4, EURAMET.TK3.3, APMP.TK4 and EURAMET.TK3.5
MEASURAND : Freezingpoint temperature of Aluminium (Al) fixedpoint cells
NOMINAL TEMPERATURE : 660.323 °C
Degrees of equivalence, D_{i} and expanded uncertainty U_{i}, relative to the CCTK4 key comparison reference value
* LNEINM was named "BNMINM" at the time of key comparison CCTK4
** INRIM was named "IMGC" at the time of key comparison CCTK4
Lab i  D_{i}  U_{i} 
/ mK  / mK  
DTI  1.38  6.00 
JV  1.41  5.10 
MKEH  2.77  4.52 
SMU  3.35  4.18 
INM(RO)  3.80  4.27 
UME  0.75  4.79 
DZM/FSB  2.43  12.78 
CMI  1.53  4.92 
GUM  4.41  4.37 
LNEINM  4.75  4.08 
MIRS  0.37  4.16 
METAS  6.25  3.65 
BEV  3.28  4.76 
NPL  1.94  3.47 
SP  3.50  4.00 
VMT/PFI  3.50  4.70 
VNIIM  3.69  3.50 
MIKES  0.49  4.98 
EIM  11.99  6.33 
INRIM  0.38  5.04 
IPQ  0.99  4.86 
CEM  1.30  7.75 
NMiVSL  2.36  5.05 
PTB  2.83  3.92 
Results are presented under A4 printable format in Summary Results (PDF file).
CCTK4 and EUROMET.TK4
MEASURAND : Freezingpoint temperature of Silver (Ag) fixedpoint cells
NOMINAL TEMPERATURE : 961.78 °C
Degrees of equivalence, D_{i} and expanded uncertainty U_{i}, relative to the CCTK4 key comparison reference value
* LNEINM was named "BNMINM" at the time of key comparison CCTK4
** INRIM was named "IMGC" at the time of key comparison CCTK4
Pairwise degrees of equivalence inside key comparison EUROMET.TK4
Lab i  D_{i}  U_{i} 
/ mK  / mK  
CMI  11.35  8.07 
GUM  6.08  7.47 
LNEINM  2.54  9.44 
MIRS  4.71  9.11 
METAS  8.81  8.89 
BEV  7.84  8.54 
SMU  5.91  13.55 
NPL  5.70  13.94 
SP  6.16  14.55 
VMT/PFI  3.81  14.65 
VNIIM  3.11  14.20 
MIKES  0.79  11.40 
EIM  2.95  10.96 
INRIM  3.98  9.44 
IPQ  1.28  11.41 
CEM  2.69  14.18 
NMiVSL  4.06  9.53 
PTB  5.63  10.70 
Results are presented under A4 printable format in Summary Results (.PDF file).
Metrology area, Subfield  Thermometry, Fixed Point Cells 
Description  Comparison of local realizations of Aluminium and Silver freezingpoint temperatures 
Time of measurements  2004  2005 
Status  Approved for equivalence 
Final Reports of the comparisons  
Measurand  Temperature: 660.323 °C for Aluminium and 961
78 °C for Silver 
Transfer device  Standard platinum resistance thermometers 
Comparison type  Key Comparison 
Consultative Committee  CCT (Consultative Committee for Thermometry) 
Conducted by  EURAMET (European Association of National Metrology Institutes) 
RMO Internal Identifier  EUROMET Project No 820 
Comments  Results published on 25 May 2008 EUROMET.TK4, EURAMET.TK3.3, APMP.TK4 and EURAMET.TK3.5 results are linked to those of CCTK4 Local realizations of Aluminium and Silver freezingpoint temperatures

Pilot institute 
PTB
PhysikalischTechnische Bundesanstalt Germany 
Contact person  D. Heyer +49 30 3481 595 or +49 30 3481 468 
Additional 
Pilot laboratory  

PTB 
PhysikalischTechnische Bundesanstalt, Germany, EURAMET 
BEV 
Bundesamt für Eich und Vermessungswesen, Austria, EURAMET 
CEM 
Centro Español de Metrologia, Spain, EURAMET 
CMI 
Czech Metrology Institute, Czechia, EURAMET 
DTI 
Danish Technological Institute, Denmark, EURAMET 
EIM 
Hellenic Institute of Metrology, Greece, EURAMET 
GUM 
Glowny Urzad Miar, Central Office of Measures, Poland, EURAMET 
INM 
National Institute of Metrology, Romania, EURAMET 
INRIM 
Istituto Nazionale di Ricerca Metrologica, Italy, EURAMET 
IPQ 
Instituto Portugues da Qualidade, Portugal, EURAMET 
JV 
Justervesenet, Norway, EURAMET 
METAS 
Federal Institute of Metrology, Switzerland, EURAMET 
MIKES 
VTT Technical Research Centre of Finland Ltd, Centre for Metrology/Mittatekniikan keskus, Finland, EURAMET 
MIRS 
Metrology Institute of the Republic of Slovenia, Ministry of the Economy, Tourism and Sport, Slovenia, EURAMET 
NPL 
National Physical Laboratory, United Kingdom, EURAMET 
SMU 
Slovensky Metrologicky Ustav, Slovakia, EURAMET 
UME 
TÜBITAK Ulusal Metroloji Enstitüsü, Türkiye, EURAMET 
VNIIM 
D.I. Mendeleyev Institute for Metrology, Rosstandart, Russian Federation, COOMET 
This page proposes printout on A4 paper (portrait) of the comparison details (best printed out using a black and white printer).
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CCTK4, EUROMET.TK4, EURAMET.TK3.3, APMP.TK4 and EURAMET.TK3.5
MEASURAND : Freezingpoint temperature of Aluminium (Al) fixedpoint cells
NOMINAL TEMPERATURE : 660.323 °C
Key comparison reference value for the nominal temperature of Al fixed point: the key comparison reference temperature, T_{R}, is the weighted average temperature calculated using the sum (u_{i}^{2} + u_{c}^{2}) of the squared uncertainties to set the weights. It has zero uncertainty by definition. 
The degree of equivalence of each laboratory with respect to the key comparison reference value is given by a pair of terms: D_{i} = (T_{i}  T_{R}) and U_{i}, its expanded uncertainty at a 95% level of confidence, both expressed in mK. U_{i} = [(2u_{c})^{2} + U_{lab i}^{2}]^{1/2}, where U_{lab i} is the expanded uncertainty of laboratory i at a 95% level of confidence. 
The degree of equivalence between two laboratories is given by a pair of terms: D_{ij}_{ }= D_{i}  D_{j} = T_{i}  T_{j} and U_{ij}, its expanded uncertainty at a 95% level of confidence (see equations 1 to 3 of the CCTK4 Final Report, pages 22 to 23), both expressed in mK. 
The reference value T_{EUR} of key comparison EUROMET.TK4 is computed as the simple mean of the EUROMET.TK4 participants' results, the EIM result being eliminated as an obvious outlier. The expanded uncertainty (k = 2) is calculated from the uncertainties of the laboratories. T_{EUR} = T_{PTB}  (1.18 +/ 1.06) mK, (k = 2) The linkage of EUROMET.TK4 results to those of CCTK4 is explained in Section 5.4 of the EUROMET.TK4 Final Report, and is based on the results of common participants to both comparisons: INRIM, LNEINM, NPL, PTB, VNIIM, and NMiVSL. T_{EUR} = T_{R} + (1.65 +/ 2.28) mK, (k = 2) 
This equation allows to deduce the degrees of equivalence of the EUROMET.TK4 participants relative to the CCTK4 key comparison reference value, each composed of the offset D_{i} and U_{i}, its expanded uncertainty (k = 2), expressed in mK. 
The pairwise degrees of equivalence inside key comparison EUROMET.TK4 are composed of two terms D_{ij}_{ }and U_{ij}, its expanded uncertainty (k = 2), expressed in mK, computed as explained in Section 7 of the EUROMET.TK4 Final Report. 
The LACOMET result obtained in EURAMET.TK3.3 is linked to the results of CCTK4 using the participation of CEM in EUROMET.TK4, whose results are linked to those of CCTK4, as described above.
The participants' results obtained in APMP.TK4 are linked to the results of CCTK4 using the common participation of KRISS and NMIJ in both key comparisons. The linkage process is explained in section 4.2 of the APMP.TK4 Final Report, and leads to the computation of the degrees of equivalence of participants in APMP.TK4 relative to the CCTK4 reference value.
The ROTH+CO.AG result obtained in EURAMET.TK3.5 is linked to the results of CCTK4 using the participation of VSL in EUROMET.TK4, whose results are linked to those of CCTK4, as described above.
CCTK4 and EUROMET.TK4
MEASURAND : Freezingpoint temperature of Silver (Ag) fixedpoint cells
NOMINAL TEMPERATURE : 961.78 °C
Key comparison reference value for the nominal temperature of Ag fixed point: the key comparison reference temperature, T_{R}, is the weighted average temperature calculated using the sum (u_{i}^{2} + u_{c}^{2}) of the squared uncertainties to set the weights. It has zero uncertainty by definition. 
The degree of equivalence of each laboratory with respect to the key comparison reference value is given by a pair of terms: D_{i} = (T_{i}  T_{R}) and U_{i}, its expanded uncertainty at a 95% level of confidence, both expressed in mK. U_{i} = [(2u_{c})^{2} + U_{lab i}^{2}]^{1/2}, where U_{lab i} is the expanded uncertainty of laboratory i at a 95% level of confidence. 
The degree of equivalence between two laboratories is given by a pair of terms: D_{ij}_{ }= D_{i}  D_{j} = T_{i}  T_{j} and U_{ij}, its expanded uncertainty at a 95% level of confidence (see equations 1 to 3 of the CCTK4 Final Report, pages 22 to 23), both expressed in mK. 
The reference value T_{EUR} of key comparison EUROMET.TK4 is computed as the simple mean of the EUROMET.TK4 participants' results. The expanded uncertainty (k = 2) is calculated from the uncertainties of the laboratories. T_{EUR} = T_{TPV}  (0.52 +/ 1.30) mK, (k = 2) The linkage of EUROMET.TK4 results to those of CCTK4 is explained in Section 6.6 of the EUROMET.TK4 Final Report, and is based on the results of common participants to both comparisons: INRIM, LNEINM, NPL, PTB, VNIIM, and NMiVSL. T_{EUR} = T_{R}  (3.48 +/ 4.16) mK, (k = 2) 
This equation allows to deduce the degrees of equivalence of the EUROMET.TK4 participants relative to the CCTK4 key comparison reference value, each composed of the offset D_{i} and U_{i}, its expanded uncertainty (k = 2), expressed in mK. 
The pairwise degrees of equivalence inside key comparison EUROMET.TK4 are composed of two terms D_{ij}_{ }and U_{ij}, its expanded uncertainty (k = 2), expressed in mK, computed as explained in Section 7 of the EUROMET.TK4 Final Report. 
CCTK4, EUROMET.TK4, EURAMET.TK3.3, APMP.TK4 and EURAMET.TK3.5
MEASURAND : Freezingpoint temperature of Aluminium (Al) fixedpoint cells
NOMINAL TEMPERATURE : 660.323 °C
T_{i}  T_{mc} : difference of Al fixedpoint temperature realized at laboratory i, T_{i}, relative to the master circulated cell (PTB/NIST Al 943) temperature T_{mc}
Cell : designation of Al cell at laboratory i
u_{i }: combined standard uncertainty of laboratory i
u_{c} = 0.5 mK : standard uncertainty representing the stability of the circulated cells
Lab i  Cell  (T_{i}  T_{mc}) / mK 
u_{i } / mK 
(u_{i}^{2} + u_{c}^{2})^{1/2} / mK 
BNMINM  Al 123  3.87  0.51  0.72 
IMGC  Al Co3  4.62  0.50  0.71 
KRISS  Al  1.36  0.90  1.03 
NIM  Al 1  3.49  0.90  1.03 
NIST  Al 942  4.63  0.19  0.54 
NMiVSL  93T267  0.74  1.93  1.99 
CSIRONML  Al 98/2  5.55  0.44  0.67 
NPL  Al 89  1.37  0.98  1.10 
NRC  Al6  4.18  0.50  0.71 
NMIJ  Al 971  1.83  0.61  0.79 
PTB  Al 972  2.87  0.55  0.75 
VNIIM  Al  2.12  0.71  0.87 
MEASURAND : Freezingpoint temperature of Aluminium (Al) fixedpoint cells
NOMINAL TEMPERATURE : 660.323 °C
T_{i}  T_{PTB} : difference of Al fixedpoint temperature realized at laboratory i, T_{i}, relative to the PTB result. PTB is the Pilot Laboratory and is the only laboratory with measurements in the four loops organized in key comparison EUROMET.TK4  see Section 5.2 of the EUROMET.TK4 Final Report
U_{Lab} _{i }: expanded uncertainty (k = 2) of T_{i}  T_{PTB}
Lab i 
(T_{i}  T_{PTB}) 
U_{Lab }_{i } / mK 
DTI  1.45  5.65 
JV  1.42  4.69 
MKEH  5.60  4.04 
SMU  0.52  3.65 
INM(RO)  6.63  3.77 
UME  2.08  4.34 
DZM/FSB  5.26  12.62 
CMI  1.30  4.49 
GUM 
1.58 
3.88 
LNEINM*  1.92  3.54 
MIRS  3.20  3.64 
METAS  3.42  3.04 
BEV  0.45  4.31 
NPL 
0.89 
2.81 
SP 
0.67 
3.46 
VMT/PFI 
0.67 
4.24 
VNIIM 
0.86 
2.86 
MIKES 
2.34 
4.55 
EIM 
14.82 
5.99 
INRIM** 
3.21 
4.62 
IPQ 
1.84 
4.42 
CEM 
1.53 
7.49 
NMiVSL 
0.47 
4.63 
PTB 
0.00 
3.36 
* LNEINM was named "BNMINM" at the time of key comparison CCTK4
** INRIM was named "IMGC" at the time of key comparison CCTK4
MEASURAND : Freezingpoint temperature of Aluminium (Al) fixedpoint cells
NOMINAL TEMPERATURE : 660.323 °C
This is a bilateral comparison carried out between CEM and LACOMET in 2009
T_{LACOMET}  T_{CEM} = 0.8 mK and U(T_{LACOMET}  T_{CEM}) = 5.4 mK (see on page 14 of the EURAMET.TK3.3 Final Report), with U being the expanded uncertainty considering a coverage factor k equal to 2
MEASURAND : Freezingpoint temperature of Aluminium (Al) fixedpoint cells
NOMINAL TEMPERATURE : 660.323 °C
T_{i}  T_{KRISS} : difference of Al fixedpoint temperature realized at laboratory i, T_{i}, relative to the KRISS result. KRISS is the Pilot Laboratory and is the only laboratory with measurements in the two loops organized in key comparison APMP.TK4  see page 4 of the APMP.TK4 Final Report
U_{Lab} _{i }: expanded uncertainty (k = 2) of T_{i}  T_{KRISS}
Lab i 
(T_{i}  T_{KRISS}) 
U_{Lab }_{i } / mK 
KRISS  0.00  5.10 
NMIJ  2.20  4.70 
SCL  4.18  4.56 
NMC, A*STAR  6.04  6.02 
CMS  0.07  5.46 
NIMT  0.43  8.28 
NMLSIRIM  11.34  7.70 
NPLI  5.83  5.12 
MEASURAND : Freezingpoint temperature of Aluminium (Al) fixedpoint cells
NOMINAL TEMPERATURE : 660.323 °C
This is a bilateral comparison carried out between VSL and ROTH+CO.AG in 2013
T_{ROTH+CO.AG}  T_{VSL} = 4.69 mK and U(T_{ROTH+CO.AG}  T_{VSL}) = 4.81 mK (see on page 11 of the EURAMET.TK3.5 Final Report), with U being the expanded uncertainty considering a coverage factor k equal to 2
CCTK4 and EUROMET.TK4
MEASURAND : Freezingpoint temperature of Silver (Ag) fixedpoint cells
NOMINAL TEMPERATURE : 961.78 °C
T_{i}  T_{mc} : difference of Ag fixedpoint temperature realized at laboratory i, T_{i}, relative to the master circulated cell (PTB Ag 6) temperature T_{mc}
Cell : designation of Ag cell at laboratory i
u_{i }: combined standard uncertainty of laboratory i
u_{c} = 0.2 mK : standard uncertainty representing the stability of the circulated cells
Lab i  Cell  (T_{i}  T_{mc}) / mK 
u_{i } / mK 
(u_{i}^{2} + u_{c}^{2})^{1/2} / mK 
BNMINM  Ag 105  3.96  1.52  1.53 
IMGC  Ag JM2  0.42  1.17  1.18 
KRISS  Ag  0.53  1.29  1.30 
NIM  Ag 9402  4.30  1.56  1.57 
NIST  Ag 921  0.11  0.43  0.48 
NMiVSL  92T199  8.39  1.93  1.94 
CSIRONML  Ag  14.3  6.42  6.42 
NPL  Ag 8/97  5.16  1.79  1.80 
NRC  Ag6  0.04  2.45  2.46 
NMIJ  Ag 981  4.01  1.58  1.60 
PTB  Ag 6  0  0.71  0.73 
VNIIM  Ag  3.43  1.08  1.10 
MEASURAND : Freezingpoint temperature of Silver (Ag) fixedpoint cells
NOMINAL TEMPERATURE : 961.78 °C
T_{i}  T_{TPV} : difference of Ag fixedpoint temperature realized at laboratory i, T_{i}, relative to the "Thermometer PTB Value", T_{TPV}, as explained in Sections 6.3 and 6.4 of the EUROMET.TK4 Final Report
U_{Lab} _{i }: expanded uncertainty (k = 2) of T_{i}  T_{TPV}
Lab i 
(T_{i}  T_{TPV}) 
U_{Lab }_{i } / mK 
CMI  7.99  7.03 
GUM  2.72  6.34 
LNEINM*  5.90  8.57 
MIRS  1.35  8.20 
METAS  5.45  7.97 
BEV  4.48  7.57 
SMU  2.55  12.97 
NPL  2.34  13.37 
SP  2.80  14.00 
VMT/PFI  7.17  14.11 
VNIIM  6.47  13.64 
MIKES  2.57  10.69 
EIM 
6.31 
10.22 
INRIM** 
0.62 
8.57 
IPQ 
2.08 
10.70 
CEM 
0.67 
13.62 
NMiVSL 
0.70 
8.67 
PTB 
2.27 
9.95 
* LNEINM was named "BNMINM" at the time of key comparison CCTK4
** INRIM was named "IMGC" at the time of key comparison CCTK4