Krypton's multiple emission lines make ionized krypton gas discharges appear whitish, which in turn makes krypton-based bulbs useful in photography as a brilliant white light source.Krypton mixes with argon as the fill gas of energy saving fluorescent lamps. Krypton's white discharge is often used to good effect in colored gas discharge tubes, which are then simply painted or stained in other ways to allow the desired color (for example, "neon" type advertising signs where the letters appear in differing colors are often entirely krypton-based).Krypton has an important role in production and usage of the krypton fluoride laser.In experimental particle physics, liquid krypton is used to construct quasi-homogeneous electromagnetic calorimeters.The sealed spark gap assemblies contained in ignition exciters used in some older jet engines contain a very small amount of Krypton-85 to obtain consistent ionization levels and uniform operation.
