June 1, 2009
The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory has been opened late last week. The world’s largest laser generation engine includes 192 ultraviolet laser beams that can be combined to an energy level of four million joules – enough to simulate temperatures and pressures that lead to stellar explosions.
Scheduled to go in operation in 2010, the NIF is claimed to enable a wide range of experiments never before possible on earth. The 10-story building houses a massive laser amplification structure that sends laser pulses with a length of 100 trillionths to 25 billionths of a second into a target chamber that scientists believe will offer more insight in the secrets of our universe, nuclear explosions and future energy technology.
[efoods] A low-energy pulse is split and carried on optical fibers to 48 preamplifier modules for initial amplification and beam conditioning. In the preamplifiers, the energy is increased by a factor of ten billion to a few joules. The 48 beams from the 48 preamplifiers are then split into four beams each for injection into the 192 main laser amplifier. Through a complex amplification system, and a distance of more than 1000 feet, each of the 192 beams is amplified to more than 20,000 joules.
Mirrors in two ten-story steel structures known as "switchyards" rearrange the parallel, linear array of the beams into a spherical configuration so that the beams can be focused into the center of the target chamber. Targets within the chamber, the NIF said, are located “with a precision that is measured in fractions of the thickness of a sheet of paper.”
“More energy will be produced by this ‘ignition’ process than the amount of laser energy required to start it. This is the long-sought goal of ‘energy gain’ that has been the goal of fusion researchers for more than half a century. NIF’s success will be a scientific breakthrough of historic significance – the first demonstration of fusion ignition in a laboratory setting, duplicating on earth the processes that power the stars,” said NIF director Edward Moses.