A gas turbine having at least one inner and outer housing part, between which two housing parts a ring channel is at least partially arranged, which ring channel circumferentially surrounds the useful flow of the working fluid prevailing during operation of the gas turbine and circumferentially surrounds the gas turbine rotor. The ring channel is designed to conduct a cooling fluid in the circumferential direction, wherein the ring channel is divided into ring sectors in the circumferential direction by separators. A tube is at least partially provided in the ring channel which fluidically connects individual ring sectors to each other, and is designed as a distributing tube, which is fluidically connected to at least one cooling-fluid line for conducting cooling fluid and has at least one outlet opening, which at least one outlet opening is designed to transfer the cooling fluid from the tube into the ring sectors.