Measurement of the Thermal Properties of Prototype Lambda Plates for the LHC

In order to power the LHC superconducting magnets, thousands of busbars will be routed from electrical feedboxes containing saturated helium at 4.5 K to magnets operating in pressurized superfluid helium at 1.9 K. Between those two volumes, the busbars will pass through special feedthroughs also called lambdaplates. This article presents heat flow measurements performed on several configurations of vertical prototype lambda-plates feedthroughs. The results show that the heat flow is strongly influenced by the configuration of the busbar insulation in the saturated helium.