Embodiments of the present disclosure relate to apparatus, systems and methods for substrate processing. A detachable substrate support is disposed within a processing volume of a processing chamber and the substrate support includes a substrate interfacing surface and a back surface. The pedestal hub has a supporting surface removably coupled to the substrate support. A hub volume of the pedestal hub includes temperature measuring assembly disposed therein positioned to receive electromagnetic energy emitted from the back surface of the substrate support. The temperature measuring assembly measures an intensity of the electromagnetic energy entering the assembly and generates intensity signals. An apparent temperature of the substrate is determined based on the intensity signals.