Blackbody models are used as referential temperature measuring gauges for radiationthermometers calibration. Their emissivity is usually determined by calculation. Thepresented paper describes an experimental device used to measure local effectiveemissivities, using an optical radiometer. The methods to measure and evaluate emissivityand temperature are described. The results are compared with the theoretical model of acylindrical-conical cavity used to calibrate radiation thermometers.

The type of data treatment is different depending on whether the comparison, inparticular a key comparison of the MRA (mutual recognition agreement), is of thehierarchical or non-hierarchical type. This term does not mean a possible hierarchy amongthe participant laboratories; nor, in the opposite sense, a non-hierarchy among them likein the MRA key comparisons, but an intrinsic characteristic of the comparison measurand ordesign. It is a typical hierarchical comparison when the comparisoninvolves artefact standards. In this case, the summary parameters of the comparison arehierarchically higher than the input dataset. In case of non-hierarchicalcomparisons, the summary parameters are generally not of a hierarchicallyhigher level than the input dataset, because the comparison dataset can be considereddrawn from a single super-population. This happens, when a single standard is circulatedfor measurement; when the measured samples are all drawn from a single batch of areference material; when the standards are all realisations of a single condition – namelya physical or chemical state. This paper will discuss in detail these two categories.

The main purpose of the paper is to describe the construction and performance of a newand novel Silver and Copper point system that combines a conventional ingot of silver orcopper in a graphite crucible, with a specially designed heat dewar or heat siphon to forma single entity. Furthermore, to add above this entity a heated collar to exactlycompensate for heat losses upwards and the stem conduction effects of the thermometerbeing calibrated. The overall construction contains no glass parts, is rugged, compact andtransportable. Its performance is similar to large quartz clad cells in floor standingheat pipe apparatus at a fraction of the size and cost.