CCT-K4, EUROMET.T-K4, EURAMET.T-K3.3, APMP.T-K4 and EURAMET.T-K3.5

MEASURAND : Freezing-point temperature of Aluminium (Al) fixed-point cells
NOMINAL TEMPERATURE : 660.323 °C

Degrees of equivalence D_i and expanded uncertainty U_i (95% level of confidence) expressed in mK

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CCT-K4, EUROMET.T-K4 and APMP.T-K4.1

MEASURAND : Freezing-point temperature of Silver (Ag) fixed-point cells

NOMINAL TEMPERATURE : 961.78 °C

Degrees of equivalence represented by D_i  and its expanded uncertainty U_i at a 95 % level of confidence, both expressed in mK.

* LNE-INM was named "BNM-INM" at the time of key comparison CCT-K4
** INRIM was named "IMGC" at the time of key comparison CCT-K4

CCT-K4, EUROMET.T-K4, EURAMET.T-K3.3, APMP.T-K4 and EURAMET.T-K3.5

MEASURAND : Freezing-point temperature of Aluminium (Al) fixed-point cells
NOMINAL TEMPERATURE : 660.323 °C

Degrees of equivalence, D_i and expanded uncertainty U_i, relative to the CCT-K4 key comparison reference value

* LNE-INM was named "BNM-INM" at the time of key comparison CCT-K4
** INRIM was named "IMGC" at the time of key comparison CCT-K4

Results are presented under A4 printable format in Summary Results (PDF file).

CCT-K4, EUROMET.T-K4 and APMP.T-K4.1

MEASURAND : Freezing-point temperature of Silver (Ag) fixed-point cells

NOMINAL TEMPERATURE : 961.78 °C

Degrees of equivalence represented by D_i  and its expanded uncertainty U_i at a 95 % level of confidence, both expressed in mK.

* LNE-INM was named "BNM-INM" at the time of key comparison CCT-K4
** INRIM was named "IMGC" at the time of key comparison CCT-K4

CCT-K4, EUROMET.T-K4, EURAMET.T-K3.3, APMP.T-K4 and EURAMET.T-K3.5

• Key comparison CCT-K4

MEASURAND : Freezing-point temperature of Aluminium (Al) fixed-point cells
NOMINAL TEMPERATURE : 660.323 °C

• Linking EUROMET.T-K4 to CCT-K4

• Linking EURAMET.T-K3.3 to CCT-K4

The LACOMET result obtained in EURAMET.T-K3.3 is linked to the results of CCT-K4 using the participation of CEM in EUROMET.T-K4, whose results are linked to those of CCT-K4, as described above.

• Linking APMP.T-K4 to CCT-K4

The participants' results obtained in APMP.T-K4 are linked to the results of CCT-K4 using the common participation of KRISS and NMIJ in both key comparisons. The linkage process is explained in section 4.2 of the APMP.T-K4 Final Report, and leads to the computation of the degrees of equivalence of participants in APMP.T-K4 relative to the CCT-K4 reference value.

• Linking EURAMET.T-K3.5 to CCT-K4

The ROTH+CO.AG result obtained in EURAMET.T-K3.5 is linked to the results of CCT-K4 using the participation of VSL in EUROMET.T-K4, whose results are linked to those of CCT-K4, as described above.

CCT-K4, EUROMET.T-K4 and APMP.T-K4.1

CCT-K4

MEASURAND : Freezing-point temperature of Silver (Ag) fixed-point 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_i² + u_c²) 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 CCT-K4 Final Report, pages 22 to 23), both expressed in mK.

Linking EUROMET.T-K4 to CCT-K4

The reference value T_EUR of key comparison EUROMET.T-K4 is computed as the simple mean of the EUROMET.T-K4 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.T-K4 results to those of CCT-K4 is explained in Section 6.6 of the EUROMET.T-K4 Final Report, and is based on the results of common participants to both comparisons: INRIM, LNE-INM, NPL, PTB, VNIIM, and NMi-VSL.
T_EUR = T_R - (3.48 +/- 4.16) mK, (k = 2)

This equation allows to deduce the degrees of equivalence of the EUROMET.T-K4 participants relative to the CCT-K4 key comparison reference value, each composed of the offset D_i and U_i, its expanded uncertainty (k = 2), expressed in mK.

The pair-wise degrees of equivalence inside key comparison EUROMET.T-K4 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.T-K4 Final Report.

Linking APMP.T-K4.1 to CCT-K4

The NIM (China) provides the link between the key comparison APMP.T-K4.1 to CCT-K4, having participated in both comparisons. The linking process is described in Section 8 APMP.T-K4.1 Final Report.

CCT-K4, EUROMET.T-K4, EURAMET.T-K3.3, APMP.T-K4 and EURAMET.T-K3.5

• Key comparison CCT-K4

MEASURAND : Freezing-point temperature of Aluminium (Al) fixed-point cells
NOMINAL TEMPERATURE : 660.323 °C

T_i - T_mc : difference of Al fixed-point temperature realized at laboratory i, T_i, relative to the master circulated cell (PTB/NIST Al 94-3) 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

• Key comparison EUROMET.T-K4

MEASURAND : Freezing-point temperature of Aluminium (Al) fixed-point cells
NOMINAL TEMPERATURE : 660.323 °C

T_i - T_PTB : difference of Al fixed-point 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.T-K4 - see Section 5.2 of the EUROMET.T-K4 Final Report
U_{Lab i} : expanded uncertainty (k = 2) of T_i - T_PTB

* LNE-INM was named "BNM-INM" at the time of key comparison CCT-K4
** INRIM was named "IMGC" at the time of key comparison CCT-K4

• Key comparison EURAMET.T-K3.3

MEASURAND : Freezing-point temperature of Aluminium (Al) fixed-point 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.T-K3.3 Final Report), with U being the expanded uncertainty considering a coverage factor k equal to 2

• Key comparison APMP.T-K4

MEASURAND : Freezing-point temperature of Aluminium (Al) fixed-point cells
NOMINAL TEMPERATURE : 660.323 °C

T_i - T_KRISS : difference of Al fixed-point 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.T-K4 - see page 4 of the APMP.T-K4 Final Report
U_{Lab i} : expanded uncertainty (k = 2) of T_i - T_KRISS

• Key comparison EURAMET.T-K3.5

MEASURAND : Freezing-point temperature of Aluminium (Al) fixed-point 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.T-K3.5 Final Report), with U being the expanded uncertainty considering a coverage factor k equal to 2

CCT-K4, EUROMET.T-K4 and APMP.T-K4.1

CCT-K4

MEASURAND : Freezing-point temperature of Silver (Ag) fixed-point cells
NOMINAL TEMPERATURE : 961.78 °C

T_i - T_mc : difference of Ag fixed-point 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

MEASURAND : Freezing-point temperature of Silver (Ag) fixed-point cells
NOMINAL TEMPERATURE : 961.78 °C

T_i - T_TPV : difference of Ag fixed-point 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.T-K4 Final Report
U_{Lab i} : expanded uncertainty (k = 2) of T_i - T_TPV

* LNE-INM was named "BNM-INM" at the time of key comparison CCT-K4
** INRIM was named "IMGC" at the time of key comparison CCT-K4

APMP.T-K4.1

The measurement results are listed in Table 9 of the APMP.T-K4.1 Final Report.