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3 Mechanical Design
3.3 Modules
The ATC will consist of ten identical modules and one (referred to as "half-module") special module. The mechanical design of each of the ten ATC modules is shown in fig. A-5 of Appendix A. The dimensions are: 231.4 x 954 x 119 mm3. The "half-module" dimensions are: 115.7 x 954 x 119 mm3. Due to mechanical tolerances of the aerogel material we estimate that the total thickness of the aerogel (including wrapping) will be 75 mm. The side walls of each module is made of Carbon fiber (the same material used for the TOF system) of 1.2 mm thickness, while the U-shaped top and bottom cover plates are made of 0.7 mm thick carbon fibers. The assembly of the module is done in three steps:
- U-shaped carbon fiber plate is laid and connected to two rectangular carbon fiber bars (the side walls)
- Aerogel cells are introduced into the module
- A second U-shaped plate is fixed to the module structure with screws
Finally, the completed module is positioned on the honeycomb support structure and fixed by screws. The shape of the bottom and upper bars is designed in order to allow for the fixation screws to be introduced from the sides rather than along the AMS z-axis which would necessitate the use of long screws and would increase the dead space of the device, thus reducing its rejection power.
Issue: Draft - Revision: 04 - Last Modified: 20 April 1997