Thermal conductivity of actinide materials measured using the 3$\omega $ method

The thermal conductivity of nuclear materials governs the conversion of heat produced from fission events into electricity and it is an important parameter in reactor design and safety.~However, it is also a challenging property to measure due to radioactivity and radiotixicity of actinides. Most of the conventional methods require usage of large samples (millimeter size at least) with an appropriate shape. The 3$\omega $-method, developed by Cahill [D. G. Cahill,~\textit{Review of Scientific Instruments},~61, 802 (1990)], is designed to work with small samples and enables to measure thermal conductivity and heat capacity of bulk and thin layered materials. In this work, we have adapted the 3$\omega $~method to measure thermal conductivity and heat capacity of various metallic and insulating samples including small single crystals of UO$_{\mathrm{2}}$~and UN. The validity of this method has been also tested by measuring thermal conductivities of several testing materials (Cu, Pt, Constantan, SiO$_{\mathrm{2}})$. The new measurement setup has been adapted to be compatible with Quantum Design PPMS system.