Development and Testing of Thermal Conductivity Test Stand

This Research and Development program, conducted at L'Institut de Physique Nucl\'{e}aire d'Orsay (France), is aimed at developing and mastering innovative Vacuum Heat Treatment (VHT) processes in order to produce high functional performance bulk niobium (Nb) superconducting radio frequency cavities for accelerators. VHT of Nb has a strong impact on thermal conductivity k(T) at cryogenic temperature and especially on the phonon peak at T$=$2 K. A new test-stand dedicated to the measurement of k(T) in the temperature range 1.6 K-30 K is developed. The test-cell allows the measurement of 4 samples simultaneously, drastically improving samples turn-over. The samples are tested as received and then tested once subjected to VHT (hydrogen outgassing, nitrogen infusion). My role was largely in the mechanical assembly of the test-cell and instrumentation, including preparation and preliminary tests: Currently, I have performed k(T) measurement at T$=$77K-85K, and similar measurement will be performed in liquid helium. The data is reported, discussed, and compared to literature.