Discharge tube for compact fluorescent lamp and compact fluorescent lamp

A discharge tube arrangement (10, 30) for a compact fluorescent lamp is provided which has a central axis (18) and longitudinal end portions, and is formed of at least one discharge tube made of glass / encloses a discharge volume which is filled with a discharge gas and has a fluorescent phosphor coating disposed on an inner surface portion of the tube. The tube forms a continuous arc path and has electrodes disposed at each end of the arc path. The discharge tube arrangement comprises a first cold chamber (13, 33) in order to control and maintain a required mercury vapor pressure, located in a longitudinal end portion of the tube arrangement. The discharge tube arrangement is further provided with at least one second cold chamber (14, 34), positioned between the longitudinal end portions of the discharge tube arrangement. The at least one second cold chamber is positioned on the wall of the tube, and has a cold chamber wall protruding substantially away from the central axis of the discharge tube arrangemen