Source, an arrangement for installing a source, and a method for installing and removing a source

A source of a solid or liquid material for gas deposition reactors, the source being insertable at least partly inside a fitting connected to a reaction space of a gas deposition reactor, the source comprising a bar element which has a first end and a second end, a chamber for a solid or liquid source material arranged on the second end of the bar element or in a vicinity thereof, the chamber comprising at least one at least partly open wall, and a tube arranged over the bar element, wherein the tube is arranged to form a cover-like isolating means arranged onto the at least partly open wall of the chamber for isolating the chamber from environment, such that the tube and the chamber are arranged to be slid with respect to one another in order to open or close the chamber after the source is installed in the fitting.