Dilithium crystal chamber

From Memory Alpha, the free Star Trek reference

The dilithium crystal chamber is a component in a starship's warp core that contains the dilithium crystals. (TNG: "Galaxy's Child", "The Drumhead", "Cost of Living")

The dilithium crystal chamber for the USS Enterprise-D was designed at Outpost Seran T-1 on stardate 40052. (TNG: "Booby Trap")

On the USS Voyager, Crewman Hogan's main responsiblity was to keep the dilithium chamber filled. (VOY: "Alliances")

[edit] Background

There are four types of dilithium chamber that have been shown to date. One was that of the NX class starship, though exactly which component of the reactor was the chamber itself was never disclosed.

The second was used on board the original configuration of the Constitution-class. It was a squat cylinder with a blunt domed top in the center of main engineering. The dilithium crystals were housed in a framework that rose out of one side of the chamber.

The next was the columnar "swirl" chamber, as shown in the Constitution-class refit and the Intrepid-class. Backstage information, including interviews with Rick Sternbach, indicate that in this model of chamber, the entirety of the column is the reaction chamber, which is lined with a layer of dilithium to moderate the reaction.

The last type is the familiar "ball" or "hub" chamber, shown throughout Star Trek: The Next Generation and Star Trek: Deep Space Nine.