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  
BNMINM  0.25  1.47 
IMGC  1.00  1.44 
KRISS  2.26  2.13 
NIM  0.13  3.49 
NIST  1.01  1.08 
NMiVSL  4.35  4.16 
CSIRONML  1.93  1.51 
NPL  2.25  2.39 
NRC  0.56  1.46 
NMIJ  1.79  1.60 
PTB  0.75  1.54 
VNIIM  1.50  1.82 
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 CCTK4
Lab i  D_{i}  U_{i} 
/ mK  / mK  
BNMINM  2.69  3.13 
IMGC  0.85  2.58 
KRISS  0.74  2.69 
NIM  3.03  6.18 
NIST  1.16  1.01 
NMiVSL  7.12  4.15 
CSIRONML  13.03  12.89 
NPL  3.89  3.97 
NRC  1.23  4.95 
NMIJ  2.74  3.29 
PTB  1.27  1.50 
VNIIM  2.16  2.40 
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  1998  2000 
Status  Approved for equivalence 
Final Reports of the comparisons  
Measurand  Temperature: 660.323 °C for Aluminium and 961
78 °C for Silver 
Transfer device  Aluminium and Silver cells, plus high temperature standard platinum resistance thermometers 
Comparison type  Key Comparison 
Consultative Committee  CCT (Consultative Committee for Thermometry) 
Conducted by  CCT (Consultative Committee for Thermometry) 
Comments  Results published on 12 March 2002 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  H.G. Nubbemeyer +49 (0) 30 3481 246 
Pilot laboratory  

PTB 
PhysikalischTechnische Bundesanstalt, Germany, EURAMET 
BNMINM 
Bureau National de Métrologie  Institut National de Métrologie, France, EURAMET 
CNRIMGC 
Consiglio Nazionale delle Ricerche  Istituto di Metrologia G. Colonnetti (until 2006), Italy, EURAMET 
CSIRONML 
Commonwealth Scientific and Industrial Research Organization  National Measurement Laboratory; became National Measurement Institute, Australia, NMIA in 2004, Australia, APMP 
KRISS 
Korea Research Institute of Standards and Science, Korea, Republic of, APMP 
NIM 
National Institute of Metrology, China, APMP 
NIST 
National Institute of Standards and Technology, United States, SIM 
NMIJ AIST 
National Metrology Institute of Japan, Japan, APMP 
NMiVSL 
Nederlands Meetinstituut  Van Swinden Laboratorium (became VSL in 2009), Netherlands, EURAMET 
NPL 
National Physical Laboratory, United Kingdom, EURAMET 
NRC 
National Research Council, Canada, SIM 
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