1. Peter.Fauland@epfl.ch EDR @ EPFL, 14.10.05 Design and first Prototype for a B eam P ipe D istance M onitoring Safety Switch

2. Peter.Fauland@epfl.ch EDR @ EPFL, 14.10.05 Requirements : Reliability of the system  „Fail-safe“ system  Simple principle of operation As little as possible additional material As a careful touching of the beam pipe is permitted....

3. Peter.Fauland@epfl.ch EDR @ EPFL, 14.10.05 Beam Pipe Distance Monitoring both during installation and data taking Top- and Bottom Boxes Side Boxes Minimum distance : 7 mm !!

4. Peter.Fauland@epfl.ch EDR @ EPFL, 14.10.05 First switch activated at 7 mm distance from the beam pipe  signal Second switch activated at 6.5 mm distance from the beam pipe  alarm Three switches under & at the front of the detector box Three switches on top & at the front of the detector box One switch at the side of the detector box Each switch consists Of two mettalic blades, Allowing a distance- Dependent signal

5. Peter.Fauland@epfl.ch EDR @ EPFL, 14.10.05 Metall blade („finger strip“) : Thickness 500 microns Beryllium Copper Switching precision < 0.250 mm Foil around the beam pipe : Thickness 100 microns Copper

6. Peter.Fauland@epfl.ch EDR @ EPFL, 14.10.05 Safety Switch for side boxes Metallic foil Stesalite piece & non magnetic blade [Design model]

7. Peter.Fauland@epfl.ch EDR @ EPFL, 14.10.05 Safety switch for top (and bottom) boxes Metallic foil Stesalite piece & non magnetic blade [Design model]

8. Peter.Fauland@epfl.ch EDR @ EPFL, 14.10.05 Next steps...  Furhter tests with different finger strips  Detailed studies on electrical connection possibilities  Studies on optimal fixation points (on the detector boxes)