At Lawrence Livermore National Laboratory, a federally funded research and development center about 50 miles east of San Francisco, scientists at the National Ignition Facility (NIF) are trying to achieve self-sustaining nuclear fusion -- in other words, to create a miniature star on Earth. The core of the NIF is a house-sized spherical chamber aiming 192 massive lasers at a tiny target. One recent laser experiment focused nearly 2 megajoules (the energy consumed by 20,000 100-watt light bulbs in one second) of light energy onto a millimeter-sized sphere of deuterium and tritium in a 16-nanosecond pulse. The resulting energetic output, while far short of being a self-sustaining reaction, set a record for energy return, and has scientists hopeful as they fine-tune the targeting, material, and performance of the instruments. The facility itself bristles with machinery and instruments, impressing the producers of the movie Star Trek: Into Darkness, who used it as a film set for the warp core of the starship Enterprise.
Inside the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory, a service system lift allows technicians to access the target chamber interior for inspection and maintenance. The goal of the NIF is to initiate controlled nuclear fusion, in the hopes of creating a new source of energy for our growing world. (Philip Saltonstall/Lawrence Livermore National Laboratory)
During construction in the late 1990s - NIF's "Grand Central Station" is its seven-story-tall Target Bay which houses the target chamber as well as the final optics assemblies, cryogenics systems, and diagnostic equipment. The chamber, a sphere ten meters (33 feet) in diameter, is covered with boron-injected concrete to absorb neutrons during NIF experiments.(Lawrence Livermore National Laboratory)
U.S. Secretary of Energy Bill Richardson, lower right, christens the 150-ton, 33-foot diameter aluminum laser target chamber at the National Ignition Facility in Lawrence Livermore National Laboratory in Livermore, California, on June 11, 1999. (AP Photo/Ben Margot)
The single largest piece of equipment at the NIF is its 130-ton target chamber. The design features 6 symmetric middle plates and 12 asymmetric outer plates, which were poured at the Ravenswood Aluminum Mill in Ravenswood, West Virginia. The plates were shipped to Creusot-Loire Industries in France, where they were heated and then shaped in a giant press. The formed plates were shipped from France to Precision Components Corp. in York, Pennsylvania, where they were trimmed and weld joints prepared. Assembly and welding activities at Lawrence Livermore National Laboratory (seen here) were performed in a temporary cylindrical steel enclosure looking much like an oil or water tank. (Lawrence Livermore National Laboratory)
In June 1999, after careful preparation, a rotating crane hoisted the target chamber and gently moved it to the Target Bay.(Lawrence Livermore National Laboratory)
After the target chamber was lowered into place, the seven-story walls and roof of the Target Bay were completed.(Lawrence Livermore National Laboratory)
The target chamber under construction. Holes in the target chamber provide access for the laser beams and viewing ports for NIF diagnostic equipment. (Lawrence Livermore National Laboratory)
Power Conditioning System - Peak power for the NIF electrical system exceeds one trillion watts, making it the highest-energy and highest-power pulsed electrical system of its kind. (Lawrence Livermore National Laboratory)
The fabrication of melted and rough-cut blanks of laser glass amplifier slabs needed for NIF construction (3,072 pieces) was completed in 2005. The amplifier slabs are neodymium-doped phosphate glass manufactured by Hoya Corporation, USA and SCHOTT North America, Inc.(Lawrence Livermore National Laboratory)
The target assembly for NIF's first integrated ignition experiment is mounted in the cryogenic target positioning system, or cryoTARPOS. The two triangle-shaped arms form a shroud around the cold target to protect it until they open five seconds before a shot.(Lawrence Livermore National Laboratory
A new "tentless" National Ignition Facility target showing the two-millimeter-diameter target capsule in the center of the hohlraum (a specially designed barrel-shaped housing for the target sphere). The tiny capsule is supported by the fill tube used to fill the capsule with fuel and a secondary stabilizing support tube at right. Both tubes are 30 microns in diameter. In previous targets, the capsule was supported by ultrathin plastic membranes known as tents; experiments indicated that the tents might be seeding hydrodynamic instabilities sufficient to interfere with the NIF implosions. (Lawrence Livermore National Laboratory)
A NIF target contains a polished capsule about two millimeters in diameter, filled with cryogenic (super-cooled) hydrogen fuel.(Lawrence Livermore National Laboratory)
NIF's final optics inspection system, when extended into the target chamber from a diagnostic instrument manipulator, can produce images of all 192 laser final optics assemblies. (Jacqueline McBride/Lawrence Livermore National Laboratory)
The National Ignition Facility at Lawrence Livermore National Laboratory requires optics produced from large single crystals of potassium dihydrogen phosphate (KDP) and deuterated potassium dihydrogen phosphate (DKDP). Each crystal is sliced into 40-centimeter-square crystal plates. Traditionally DKDP has been produced by methods requiring approximately two years to grow a single crystal. With the development of rapid growth methods for KDP, the time required to grow a crystal has been reduced to just two months. NIF requires 192 optics produced from traditionally grown DKDP and 480 optics rapidly grown from KDP. Approximately 75 production crystals were grown totaling a weight of nearly 100 tons. (Lawrence Livermore National Laboratory)
This view from the bottom of the chamber shows the target positioner being inserted. Pulses from NIF's high-powered lasers race toward the Target Bay at the speed of light. They arrive at the center of the target chamber within a few trillionths of a second of each other, aligned to the accuracy of the diameter of a human hair. (Philip Saltonstall/Lawrence Livermore National Laboratory)
Seen from above, each of NIF's two identical laser bays has two clusters of 48 beamlines, one on either side of the utility spine running down the middle of the bay, eventually reaching the target chamber. (Jacqueline McBride/Lawrence Livermore National Laboratory)
Temperatures of 100 million degrees and pressures extreme enough to compress the target to densities up to 100 times the density of lead are created in the target chamber. Surrounding the target is diagnostic equipment capable of examining in minute detail the arrival of the laser beams and the reaction of the target to this sudden deposition of energy.(Jacqueline McBride/Lawrence Livermore National Laboratory)
The interior of the NIF target chamber. The service module carrying technicians can be seen on the left. The target positioner, which holds the target, is on the right. (Lawrence Livermore National Laboratory)
Lawrence Livermore National Laboratory technicians John Hollis (right) and Jim McElroy install a SIDE camera in the target bay of the National Ignition Facility (NIF). The camera was the last of NIF's 6,206 various opto-mechanical and controls system modules to be installed. (Jacqueline McBride/Lawrence Livermore National Laboratory)
Director Edward Moses briefed California Governor Arnold Schwarzenegger at the NIF target chamber, on November 10, 2008.(Jacqueline McBride/Lawrence Livermore National Laboratory)
NIF's millimeter-sized targets must be designed and fabricated to meet precise specifications for density, concentricity and surface smoothness for NIF experiments. LLNL scientists and engineers have developed a precision robotic assembly machine to manufacture the small and complex fusion ignition targets. (Lawrence Livermore National Laboratory)
California Governor Arnold Schwarzenegger examines a model of a target while touring the National Ignition Facility in Livermore, California, on November 10, 2008. (AP Photo/Lea Suzuki, Pool)
A new viewing window recently installed on the NIF Target Chamber allows members of the NIF team and visitors to see inside the chamber while it is vacuum-sealed for experiments. NIF Team members Bruno Van Wonterghem (left), Jim Nally (pointing) and Rod Saunders watch through the viewing window as the Final Optics Damage Inspection System is deployed.(Lawrence Livermore National Laboratory)
댓글 없음:
댓글 쓰기