The principle and experimental details of the isopiestic method
applied in this work were described previously by Ipser et al. [5,6].
A schematic diagram of the particular setup used in the present
investigation is shown in Fig. 1. The apparatus is essentially made
of quartz glass. It consists of an outer tube of 38 mm O.D. with one
end closed and the other end fitted with a ground joint which can
be connected to a vacuum pump. A quartz glass crucible with
32 mm O.D. is placed at the bottom serving as a reservoir for Cd.
On top of the reservoir, a quartz glass spacer of suitable height and
a quartz supporting tube (15 mm O.D.) are located where the
tantalum crucibles containing pure Ce as samples are inserted. An
inner tube of 7 mm O.D. with its upper end widened to 32 mm O.
D. is used as a thermocouple well. The apparatus can be sealed
under vacuum in its upper part.