The name refers to the twelve individual beamlines used to amplify the laser energy.
Compared to most Nd:glass laser ICF experiments, GEKKO is also quite small, with beamlines about 10 m long.
The 12 beams of the GEKKO laser are capable of delivering about 10 kilojoules per 1–2 ns pulse (10–20 terawatts).
From 1996 to 1997 the GEKKO system was upgraded with a ~0.4 kJ, 0.5 PW ultra-short pulse beam which was used to investigate a promising new technique of ICF known as "fast ignition", where the compression phase of target implosion is decoupled from the heating phase.
[1] GEKKO is currently being upgraded with the addition of a second "side-by-side" laser, the LFEX (Laser for Fast Ignition Experiment), part of the FIREX-1 program, in order to deliver a 10 kJ pulse of energy to a target in 10 picoseconds, further exploring the fast ignition regime.