A Fully Automated Measurement System of Thermal Conductivity Using a Helium Refrigerator.

We have developed a fully automated measurement system of thermal conductivity combining a helium refrigerator and a data acquisition, processing and control system (NEC-9800 series) with RS 232 CGPIP lines.The thermal conductivity is measured by a conventional steady-state heat flow method in the range of 15-200K.It is found that a measurement of a NIST standard ref erence material ensures high accuracy of 3% for this apparatus.Furthermore, the measured thermal conductivity of high-Tc oxide superconductor (BPSCCO) agrees with the typical data reported by a number of groups, and shows a clear enhancement below Tc.