INTEGRAL signal multiplexing

Since its inception the INTEGRAL high energy instrumentation was designed t o use three very innovative technologies: massive active shielding, positio n sensitive detector planes and spatial signal multiplexing. Background red uction improves S/N ratios and spatial multiplexing provides the required i maging capabilities. The design, development, manufacturing and qualification of the coded apert ure systems for SPI, IBIS and JEM-X have been under GAGE responsibility sin ce the ESA instrument selection in 1995. The coded aperture systems develop ment has been accomplished during the last four years in close connection w ith the detector plane designers. The scope of this paper is to report the status, the scientific performance s and optical properties of the three coded aperture systems. We also give some details about the technology used and some remarks about the key mask design parameters.