Abstract: A turntable (1) and a device comprising a turntable suitable for disc-shaped information carriers having a central opening. The turntable comprises a centering element (8) comprising a cone-shaped centering portion (12), which centering element is rotatable about an axis of rotation and is movable in axial direction against a spring force. The centering element further comprises a substantially cylindrical portion (11) which adjoins the end of the cone-shaped centering portion positioned nearest the central axis.

Abstract: Method and device for rotating a wafer which is arranged floating in a reactor. The wafer is treated in a reactor of this nature, and it is important for this treatment to be carried out as uniformly as possible. For this purpose, it is proposed to rotate the wafer by allowing the gas flow to emerge perpendicular to the surface of the wafer and then to impart to this gas a component which is tangential with respect to the wafer, thus generating rotation. This tangential component may be generated by the provision of grooves, which may be of spiral or circular design.