Table 2 lists the purity of the fixed-point substances, the container and holder materials, the amount of sample used, the immersion depth of the SPRTs in the thermometer well of the sample container, the controlled operating environment, and the uncertainties associated with the measurements using the fixed-point devices.
The wells for the long-stem SPRT are made sufficiently deep to eliminate "stem conduction." The depth of the thermometer well of the container for the high-purity fixed-point substance is limited.
In the morning with a "check (HT)SPRT" in the thermometer well, the furnace temperature is reduced to initiate the freeze.
Next, a long heater is inserted into the thermometer well to form an inner melt.
The generic sealed cell consists of a permanently sealed pressure vessel with a ballast volume; a sample volume for the condensed portion of the sample; a thermometer well insert; a heat exchanger; and a heating element.
The thermometer well inserts are large enough to accommodate three capsule-type thermometers, either CSPRTs or RIRTs.
The outer vacuum jacket surrounds three sets of thermal radiation shields around the 300 [cm.sup.3] copper sample cell, containing 15 mol of Ar, into which seven long, thin-wall stainless steel thermometer wells were inserted and soldered.