The precession of individual spins on partially oxidized Si(111) surfaces has been detected using a scanning tunneling microscope. The spin precession in a constant magnetic field induces a modulation in the tunneling current at the Larmor frequency. This radio-frequency signal is shown to be localized over distances less than 10 Å and follows the expected magnetic field dependence.

The possibility of using GaSe detectors for x‐ray beams dosimetry has been evaluated. Direct current produced by high fluxes of 130 and 170 kV x ray at different exposure rates was measured.