Genova 3/2/1998 The module has been changed according to the Pixel Layout meeting of January 1998. The material break out of the module and its geometric characteristics are indicated in the Excel tables. The thin thermal tile is 0.4mm thick, the step to the thick tile is of 0.6mm, the cooling tube is made of two parts: a) omega piece (0.3mm thick, 3-ply CF, 75% Carbon content after curing) b) glue (0.1mm thick, epoxi or equivalent) to cover the C-C surface facing the coolant and to bond the edges of the omega to the C-C surface. The basic assumptions are (lenght x width x thickness in mm): sensor size : 62.4 x 18.2 x 0.25 (0.2 for B_layer) front-end chip size : 7.4 x 10.6 x 0.15 MCC size : 10.0 x 7.0 x 0.15 kapton size : 56.4 x 16.6 x 0.15 The kapton circuit has 6-layers (three for signal and three for power). Each signal layer is made of 12um of polymide and 4um of Aluminum, the Al coverage is assumed to be 30%. Each power layer is made of 16um of polymide and 16um of Aluminum, the Al coverage is assumed to be 90%. The power supplies (both high and low voltages) are transmitted to each individual module through the power layers and the aluminum bridges (40 Al wire bonds, each of 75 um diameter) joining each module to the preceeding one. The power layers are designed such as to have a difference of low voltage of <100 mV in any of the front-end chips of a stave. The design shown doesn't therefore need any other cable going out (apart from the optical fibres, which are not designed but taken into account in the material budget presented in the Excel tables). The kapton circuit is glued on the detector backplane ,the thickness of the glue is 12.5um and the 1st layer of the hybrid circuit is 12um of kapton. For the time being there are no decoupling capacitors and no temperature sensors. The weight of the stave is around 50g (details in the Excel table for composite solution). The radii indicated in the 3-cylinder drawings are those of the center of the central sensor. The central sensor stays on a thin thermal support, there are therefore 7 sensors at the nomianl radius and 6 sensors at a 0.6mm smaller radius.