A time projection chamber is a detector technology employed in high energy particle physics that can determine the (x,y,z) position of an event within it with incredible accuracy. The chamber, usually built as a cylinder, is filled with some ionizing medium. In the case of LUX, that material is liquid xenon. When a particle travels through the chamber, it produces ionization electrons. A strong electric field is constantly applied along the z-direction of the chamber, and the ionization electrons drift because of this electric field to the collector. The collector can determine the (x,y) position of the event, and the drift time of the electrons from the event site to the collector provides the z position.