Experimental investigations of He II heat transfer through a short section of LHC inner triplet quadrupole heat exchanger

The LHC inner triplet quadrupoles, cooled by pressurized He II, are subjected to a total heat load of more than 7 W/m at nominal luminosity. The heat absorbed in pressurized He II will be transferred to the saturated, two-phase He II via a corrugated copper pipe. Experimental investigations of He II heat transfer across the corrugated pipe are reported. The test sample of corrugated pipe is filled with pressurized He II and with saturated He II on the outside. The maximum heat flux to the test sample is up to 145 W/m /sup 2/. The characteristics of the corrugated copper pipes under investigation are the Kapitza resistance, thermal conductivity of the material and the geometry of the pipe. The test results for a series of bath temperatures and surface treatments are included. (5 refs).