A clamp for securing a terminal end of a wire to a surface electrode formed on a cylindrical tube includes a first semicylindrical element. A second semicylindrical element is configured to be attached to the first semicylindrical element to form a tubular clamp structure that is adapted to be clamped around the cylindrical tube. The tubular clamp structure includes an interior surface configured to securely hold a terminal end of a wire against a surface electrode formed on the cylindrical tube.