Page 395 - High Power Laser Handbook

The National Ignition Facility Laser 365

Figure 14.2 NIF’s large optics each have an area of approximately 40 cm ×
40 cm. The optic shown here—a 7.7-m focal length wedged lens used to
focus one beam onto the target—was used during the 2006 campaigns
discussed in Secs. 14.4 to 14.6. This photograph was taken after the lens
was exposed to 11 shots with 8 to 9.4 kJ of 351-nm light (equivalent to 1.6
to 1.8 MJ of 351-nm light for the full 192-beam NIF).

Laser beams
in 2 rings

Ablator
(Be)
9.1
5.1 mm mm DT ice
Capsule 1 mm DT gas fill
(Be)
Hohlraum wall:
– High-z mixture
(cocktail)
Hohlraum fill:
– Low pressure
(He)

Laser entrance hole
with window
Figure 14.3 All of the 192 NIF laser beams are schematically shown focused into
a single cylindrical hohlraum. Each cone comprises four individual beams. The
hohlraum is approximately 10 mm × 5 mm in diameter. The laser entrance hole is
about 2.5 mm in diameter. Each laser beam will be pointed to a precise location on
the hohlraum wall and will generate x rays that will then drive the implosion of the
central 1-mm radius spherical fusion capsule. The ensuing nuclear reaction is
expected to release about 10 MJ of energy.
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