Abstract: A thermal conductivity cell is described whose elements are well protected against short term temperature fluctuations, changes in flow rates, leaks, and vapor pressures of construction materials. The sample and reference chambers are formed within a relatively large copper block with a controlled thermal time constant. The thermal elements are isolated from the gas flow paths by porous metal plugs which are thermally "clamped" to the block. Element feed-throughs are potted in thermally conductive epoxy to minimize the effect of temperature gradients.

Abstract: A material holder is fabricated by press-fitting and welding a series of discs into an open cylinder housing. Shrinkage of the cylinder from the welding of the first disc is accommodated by selecting a smaller disc for the second press-fit. A support post is welded to the last disc and shrinkage of that disc from welding of the support post is accommodated by selecting an oversize disc for attachment to the support post. Shrinkage of the last disc also compensates for additional shrinkage of the cylinder from welding of the second disc.