A medical probe, consisting of an insertion tube having a distal end configured for insertion into a body of a patient and containing a lumen having an electrical conductor for conveying electrical energy. The probe also has a conductive cap attached to the distal end of the insertion tube and coupled electrically to the electrical conductor, the cap including a side wall having multiple longitudinal bores therein. There are a plurality of thermocouples disposed in respective ones of the longitudinal bores, and an electrically conductive cement at least partially fills the longitudinal bores so as to secure the thermocouples in the bores while making electrically conductive contact between the thermocouples and the conductive cap.
