Sirocco^™

The hardest problem at a checkpoint is the gap between shouting and shooting. There is nothing in between, so escalation goes from words to rounds in one step. SIROCCO is that missing step. A 95 GHz beam stops in the outer 0.4 millimetres of skin and produces a heating sensation nobody can stand still for. The crowd moves. Step out of the beam and it is over, with nothing to treat and nobody to bury.

95 GHz is not a preference. It is the only frequency where three things coincide. There is an atmospheric window between the oxygen lines at 60 and 118 gigahertz, so the beam reaches. The absorption depth is 0.4 millimetres, which is above every structure that could be damaged and below none of the nerve endings that report pain. And a source exists at this power. At 35 GHz the energy reaches the dermis and the injury risk climbs. At 2.45 GHz it heats organs. The physics that makes it work is the same physics that makes it safe.

It is built on the effect the fielded Active Denial System demonstrated. What is ours is the packaging, the price, and the dose control below.

At the power a 900 metre engagement needs, the same beam delivers 506 watts per square centimetre at 100 metres. That is a burn in six tenths of a millisecond. No operator reaction time protects against a threshold measured in milliseconds, and no timer written into a procedure protects against it either.

So the power tracks the range. A rangefinder feeds the interlock controller directly, and commanded power follows the square of the distance to hold five watts per square centimetre on target at every range in the envelope. That needs 101 to 1 of control. The tube gives three to one by turning the beam current down. The remaining thirty four comes from switching the electron gun grid at a kilohertz, and skin has a thermal time constant of 1.14 seconds, which is eleven hundred switching periods. The tissue integrates it. The target feels a smooth lower power, not a pulse train.

Then a second loop closes on the person, not on the model. A thermal camera boresighted to the beam reads the actual skin temperature of the spot sixty times a second and cuts emission at 47 degrees, three degrees below where a first-degree burn begins. That loop is what survives wet clothing, an odd reflectivity, metal on skin, or an error in our own propagation model. Detection to beam off is 34 milliseconds. The skin crosses those last three degrees in about two hundred.