PHOENIX -- The head of a special legislative panel on border security wants to use some of the money people across the nation to build a border fence instead for invisible buried sensors.Sen. Al Melvin, R-Tucson, said there are places where a fence makes sense.But Melvin, who chairs the Joint Border Security Advisory Committee, said a physical barrier is not always possible or practical. And the issue, he said, goes beyond whether the federal government or private landowners will give permission.