3.6 The hadron stop and the connecting tunnel to the LEP/LHC

The hadron stopper chamber will be 26 m long over all, and 6 m in diameter. The walls of this chamber will be of in-situ concrete and at its southern end will be a tunnel segment 20 m long and 3.10 m in diameter, lying perpendicular to it. At the far end of the segment will be a chamber 10 m long and 4 m in diameter. This chamber will in turn be linked to the LEP/LHC tunnel by a connecting passage 224 m long and 3.10 m in diameter. This underground connecting passage is essential because the hadron stop chamber will not be accessible from the structures above it and CERN wishes to avoid an additional shaft from the surface. This connecting passage will pass 7 m below the level of the LHC tunnel.

The walls and ceilings of all the interconnecting passages and connection chambers will be lined in shotcrete. At its downstream end, the hadron stop chamber will house the first muon detector station.

3.7 The second muon detector chamber

This second chamber, 6 m in diameter and 3.50 m long will be located 67 m from the first chamber and along the axis of the beam. It will have in-situ concrete walls and be linked to the above-mentioned connection chamber by a tunnel 3.10 m in diameter (c.f. Figure 14 on page 23 ). The walls and ceilings of all the interconnecting tunnels and connection chambers will be of shotcrete.

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