  We present Scanning Tunneling Spectroscopy measurements at 0.1 K using tips
made of Al. At zero field, the atomic lattice and charge density wave of
2HNbSe2 are observed, and under magnetic fields the peculiar electronic surface
properties of vortices are precisely resolved. The tip density of states is
influenced by the local magnetic field of the vortex, providing for a new probe
of the magnetic field at nanometric sizes.
