Page 399 - High Power Laser Handbook

368 So l i d - S t at e La s e r s The National Ignition Facility Laser 369

Average St Dev of
Measured Total Deviation Beamline
Shot Desired Beamline Bundle of Average Energies
Sequence 1v Energy 1v Energy 1v Energy from from
Number (kJ) (kJ) (kJ) Desired (%) Mean (%)
1 19.02 19.20 153.6 +0.98 0.84
2 " 19.15 153.2 +0.68 0.94
3 " 19.11 152.9 +0.50 0.67
4 " 19.10 152.8 +0.43 0.89
Table 14.1 Analysis of the 1ω Beam Energetics of Four Identical 19-kJ Shots

14.4.2 Power versus Energy Operating Envelopes for NIF
A system shot is defined as any event in which the flash lamps are
fired in a bundle with all of the bundle’s main laser (1ω) optics
installed. From commissioning the first four NIF beamlines in April
2001 to the time of the initial tests in 2006, NIF had fired more than
600 system shots. Figure 14.6 shows a summary of the 1ω shots fired,
together with the NIF standard 1ω operating envelope, as set in
LPOM. This envelope does not represent the absolute limits of

2
Fluence (J/cm )
0 5 10 15 20
8
7 Standard operating
0.2 ns impulse envelope
6 5 0.8 ns 1 ns 1.5 ns 2 ns 2.4 ns 3 ns 3.5 ns Shaped pulses 4
Power/beam (TW) 4 5 ns 3 Intensity (GW/cm 2 )

2 3 10 ns 2
20 ns 1
1 23 ns
0
0 5 10 15 20 25 30
Energy/beam (kJ)
Figure 14.6 Plot of 1ω peak power per beam versus 1ω energy per beam
for initial NIF shots. The thin solid line is the laser performance operations
model (LPOM) “equipment protection” operating limit.