Support arrangement for supporting a radiation projection system in a substrate processing apparatus, the support arrangement comprising: a support body for supporting the radiation projection system; electrical wiring for supplying voltages to components within the radiation projection system and/or for supplying control data for modulation of radiation to be projected onto a target surface by the radiation projection system; optical fibers, for supplying control data for modulation of radiation to be projected onto a target surface by the radiation projection system, and a cooling arrangement comprising one or more fluid conduits for cooling the radiation projection system; the electrical wiring, the optical fibers, and the cooling arrangement being at least partly accommodated in and/or supported by the support body.