This week, the Los Angeles County jail began testing a new laser weapon — the Assault Intervention Device — that could make prisons safer for guards and inmates alike. (See a video of the weapon in use below.) Here's more about L.A.'s new "pain gun":

Why a laser gun?
Officials hope that the device, which causes an excruciating burning sensation but doesn't inflict any lasting physical harm, will allow corrections officers to break up fights without putting themselves in harm's way. 

How does the device work?
The laser gun, which is controlled with a joystick, emits focused beams of radiation that penetrate the skin up to 1/64 of an inch. The beams are optimized to stimulate nerve endings and cause intense pain.

Just how intense is the pain?
"I equate it to opening an oven door and feeling that blast of hot air," Sheriff's Commander Bob Osborne told the Daily Mail. A "60 Minutes" reporter gave a more provocative description, likening the feeling to that of being scalded with hot water. Raytheon, the company that made the weapon, claims the deep burning sensation is "intolerable."

How long does the pain last?
It "immediately ceases" when the target moves way from the beam, Raytheon claims. The longest period most people can endure being "fired" upon is three seconds.

Have these devices ever been used before?
Raytheon originally produced a bigger version of the device called the Active Denial System, which the military intended to use for crowd control in Afghanistan and Iraq. But before the device was ever deployed, it was recalled for unknown reasons, reports John Hudson in The Atlantic. Whereas the Assualt Intervention Device only targets a small portion of the body, the military version can cause pain from head to toe.

Will other jails adopt this technology?
The National Institute of Justice is evaluating the laser gun for six months, John Adams reports at The federal agency is deciding whether to approve it for use in jails nationwide.

Sources:, Daily Mail, The Atlantic,