Abstract: We describe a process chamber, an apparatus, a modular system, a method, a safety device, a positioning system and a system for producing a three-dimensional workpiece and/or for use thereof when producing a three-dimensional workpiece. The process chamber for producing the three-dimensional workpiece via an additive layer construction method comprises: a material supply unit comprising a substantially ring-like shaped end portion at a first side of the process chamber, wherein the material supply unit is adapted to supply, via the end portion, material to a carrier on which the material is to be processed by the process chamber for producing the three-dimensional workpiece, and an opening at the first side of the process chamber for processing, by the process chamber, the material supplied on the carrier in order to produce the three-dimensional workpiece, wherein the substantially ring-like shaped end portion surrounds the opening.