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NEWS

We interrupt our usual opposition to licensing to suggest it for heat-ray weapons

From "Safety fears as US demonstrates crowd control heat-ray weapon," by Ian Sample, The Guardian Unlimited, 26 January 2007:

"It looks like a table top stuck on a Humvee, but to the US military it is a revolutionary new weapon, a controversial heat-ray destined to change the face of conflict by dispersing mobs, protecting military bases and sorting friend from foe without inflicting injuries.

"Called Silent Guardian, the prototype fires a high-intensity beam of [95 GHz radio waves], inflicting a burning sensation like a light bulb pressed against the skin.

"After 12 years in development it has been demonstrated in public for the first time, at Moody air force base in Georgia.

"For the US defence department it marks the beginning of an era of 'non-lethal, directed energy, counter-personnel' weapons, intended to cause temporary pain instead of killing or maiming. But critics yesterday raised fears that the weapon could cause serious, even life-threatening burns through accident or misuse.

"During the demonstration a two-man crew used built-in rangefinders to target volunteers playing the part of angry rioters 500 metres away. Those hit by the beam jumped out of the way immediately to escape the sudden flash of heat.

"The beam has a range of up to 1km, 10 times that of other non-lethal weapons such as plastic bullets or beanbag-firing guns. The waves penetrate clothing, but travel less than half a millimetre into the skin, where they cause water molecules to heat up. Within seconds, the beam heats the skin to around 50°C (122°F). Military officials plan to use the so-called Active Denial System to keep would-be attackers from approaching military installations or navy ships in dock, or for repelling mobs. It may also be useful in sorting combatants from bystanders, who are more likely to quickly leave the scene.

"Speaking from the Pentagon yesterday, Lieutenant-Colonel Brian Maka said the device, which is not expected to be ready for deployment until 2010, was built to 'stop, deter and turn back an adversary at a distance that lessens the potential for causing injury'.

"But Neil Davison, an expert in non-lethal weapons at the Disarmament Research Centre, Bradford, said that in tests so far volunteers had been allowed a cooling off period after being hit before being targeted again. 'There's no way of guaranteeing people won't be targeted for longer in a real situation,' he said.

"Jürgen Altmann, an expert in military technology at Dortmund University, found that if the beam is tracked on a person for longer, the skin temperature can quickly rise above 55°C and begin to burn.

" 'Even if they build in a mechanism that limits it to work for only a few seconds at a time, people can immediately be re-targeted,' he said. 'If more than 20% of their body receives second or third degree burns, it's potentially life-threatening.'

"According to papers released under freedom of information requests, mishaps during trials have caused blistering at least six times and one second-degree burn when the beam was fired on too high a setting. According to the US military, the risk of injury is less than 0.1%."
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CNN broadcast a video of the heat ray demo on 25 January. According to reporter Roxanne Haynes' voice-over, "This weapon does not cause injury and extensive tests show there are no side-effects."

A story by R. Colin Johnson for EE Times ("Pentagon readies ray gun," 26 January) describes the technology in more detail:

"The current demonstration platform mounts all hardware inside a Humvee retrofitted with an electric motor. The Humvee's regular diesel engine was disconnected from drive train and fitted with a 100 kwatt (85 kwatts continuous) electricity generator to power the gyrotron tube...

"The gyrotron itself is a high-powered electron tube that accelerates electrons via cyclotron motion caused by the magnetic field. The electrons travel in a circle so that the accelerating voltage can be repeatedly applied to achieve relativistic speeds (near the speed of light) before emitting...

"The electricity drives the 3.7-Tesla superconducting magnet, a refrigerator that cools the magnet to 4 degrees Kelvin and a bank of high-voltage converters that feed the gyrotron tube. The 95-GHz cyclotonic oscillations generate a millimeter-wave energy beam that penetrates the skin to about 1/64th-of-an-inch...

"Using a display, troops could direct the beam accurately, enabling the weapon to disperse crowds in predictable, repeatable patterns [said Diana Loree, area manager for the Active Denial System]. Besides ground vehicles, the Navy is expected to develop a ship-mounted version and the Air Force a long-range airborne version for fixed-wing gunships..."

[RF Weapons - 30 January 2007]