The pain beam is moving ahead:
Active Denial Technology exploits the body’s natural defense mechanism that induces pain as a warning to help protect it from injury. It uses a transmitter producing energy at a frequency of 95Ghz and an antenna to direct a focused, invisible beam to a subject at the speed of light and penetrate the skin to a depth of less than 1/64 of an inch. This produces an escalating heating sensation that becomes intolerable in seconds, and forces the subject to flee. The sensation immediately ceases when the individual moves out of the beam or when the system operator turns it off. Despite this sensation, the beam does not cause injury because of the shallow penetration depth of energy at this wavelength and the low energy levels used.
Mentioned in MO last fall.