1. 1 US Pixel Mechanics Role Global support structureIntermediate support structureLocal support structure Stave SectorDisk Barrel x (9-11) x5 x (22,40,56) x5 x3 LBNL Europe Final assembly at CERN

2. 2 Pixel Mechanics Prototype end frame section fabricated by December 1999. Thermal/mechanical prototype disk fabricated and tested successfully for stability. Second full prototype disk to be tested by next month. Evaporative cooling tests of disk sectors successfully done.

3. 3 Pixel Mechanics Status Dozens of prototype disk sectors have been built and tested. Baseline exists with alternative in case of problems with baseline. Evaporative cooling(confirmed as ATLAS baseline) of sectors demonstrated. Substantial thermal headroom. System complex -> need of evaporative cooling capability in US to meet schedule - for realistic test before reaching CERN. This is new. One full disk thermal/mechanical prototype tested at LBNL. Second about to be tested(at Hytec, Inc). Full-size frame prototype fabricated successfully. ATLAS Final Design Review of Local Supports(sectors) completed successfully in June. PRR of local supports and FDR of rest of mechanics scheduled for December - tight but feasible. In general, mechanical structures in good shape (so far) but critical issue is interface to cable and coolant plant - integrated design - see next page.

4. 4 Pixel Mechanics - Critical Issues Design and integration of cabling, fiber optics, coolant connections with mechanical structure is current critical issue. Is there enough space? Strain relief. Electrical issues. Interferences…... CAD modeling and physical modeling limited by lack of design => build prototypes. Requires building complete chain from pixel module to power supply in realistic way. In progress.  5m flex cable production in place.