On Target: Designing for Ignition

The $1.2-billion National Ignition Facility (NIF), now under construction, will permit scientists to perform experiments for the Department of Energy's Stockpile Stewardship Program to ensure that America's nuclear arsenal remains safe and reliable. The success of NIF ignition experiments will depend upon the intricate design of 2-millimeter-diameter capsules that contain a central reservoir of deuterium-tritium (D-T) gas, a frozen D-T solid-fuel layer, and an outer ablator layer. Target designers have tested different ablator materials, including polyimide (best at high temperatures) and beryllium (best at low temperatures). Capsules will be cooled to 18 kelvins (colder than liquid nitrogen) to maintain in equilibrium the central, relatively low-density D-T gas and the high-density, 80- to 100-micrometer-thick D-T ice layer. For at least the first several years, ignition experiments will use indirect drive, in which laser light heats the inside of an open-ended gold cylinder, called a hohlraum, that encloses the ignition capsule.

A New View of the Universe

A laser guide star and adaptive optics system developed at Lawrence Livermore is making astronomers' views of the heavens clearer than ever before. Livermore's sodium-laser guide star provides an artificial reference for viewing distant or dim celestial bodies with adaptive optics, which sharpen the blurring of images caused by our atmosphere. One system has already been installed on the University of California's Shane telescope on Mount Hamilton in California, and another is now being installed at the Keck Observatory on Mauna Kea in Hawaii.

Research Highlights

Quantum Molecular Virtual Laboratory

AAA in the Sky for Satellites

and LLNL Disclaimers

UCRL-52000