Experiment Proposal - opera - Infn

Figure 38: Possible design of the wall suspension.
provides horizontal access to the rows of bricks from the sides and is associated with an automatic system
for brick installation and removal.
The wall structure bears collectively the weight of the entire brick wall. Using high resistance stainless
steel bands of 0.8 mm thickness, the structure weight represents less than 0.5% of the total weight.
Different ways of attaching the trays can be considered; they can be directly welded to the vertical
bands or mounted at the installation stage on transverse bands linking the vertical ones. Solutions in
which complete wall parts can be built in advance seem preferable. After being manufactured outside,
half-wall structures are introduced in the hall, suspended from an assembly tool and joined together
before being put in place.
Each brick wall is coupled to the the electronic trackers consisting of two planes of scintillator strips
oriented along the X and Y directions, respectively. The wall structure can also be used to support the
electronic Target Tracker planes. They could hang directly from the main supporting beams or they could
be attached to the wall structure itself. In the latter case, vertical and horizontal tracker plane elements
are mounted on the upstream and downstream faces of each brick wall, respectively. Alternatively,
vertical scintillator package envelopes are suspended from supporting beams and maintained in place on
the wall structure with the help of folded metallic bands. Horizontal scintillator packages are also kept
by folded metallic bands. The envisaged solutions provide the required mechanical positioning of the
tracker relative to the bricks, compactness and rigidity.
The bricks are moved in and out of their tray being contained within individual plastic holders. This
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