through the wire mesh as discussed below in a direction perpendicular to the plane of the separator 9 in fig2 in a similar manner the particular gas in connector 5 will enter semi annular compartment 13 g and then pass through an aperture 53 in the semi annular wall portion 13 d to enter inner gas chamber 50 g the gas supplied through connector 6 similarly enters outer gas compartment 13 k passes through aperture 52 in inner wall portion 13 b and passes into inner gas chamber 50 c gas entering through connectors 7 such as an inert or carrier gas enters outer chambers 13 f 13 h 13 j and 13 l in a similar manner in this case the gas passes directly into inner chambers 50 f 50 h 50 b and 50 d respectively these chambers are narrow slots between radial wall portions 51 e and 51 f 51 g and 51 h 51 a and 51 b and 51 c and 51 d respectively in a preferred embodiment of the present invention as noted above the entire separator 9 is a single piece and is retained in place solely by being clamped between the top slot 10 and the injector plate 12 in this manner by removing the top plate 10 it is a relatively easy task to remove the separator 9 and replace it with a new separator 9 which can have an entirely different configuration i e with a different selected number of gas chambers for a particular application this permits a single reactor to be applicable to a number of different processes for growing epitaxial layers on various substrates again by simply replacing the separator 9 and possibly altering the gas feed through a variety of gas inlets associated therewith the.