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WP4 Wire Issues. Wire issues with respect to the EM measurements Perturbation of the eigenmodes Calls for a thin wire – as thin as possible RF signal stimulus Excellent conductivity, not too thin wire (Ag + Au plating!) Impedance matching
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WP4 Wire Issues Wire issues with respect to the EM measurements • Perturbation of the eigenmodes • Calls for a thin wire – as thin as possible • RF signal stimulus • Excellent conductivity, not too thin wire (Ag + Au plating!) • Impedance matching • None, single or both ends, weight limitations to minimize wire sag! • Mechanical positioning • High tensile strength, low weight material (hardened CuBe) for horizontal arrangement (low sag), see“Stretched Wire Mechanics", Gordon Bowden (SLAC), IWAA2004, CERN, Geneva, 4-7 October 2004 • Wire eigenmodes (microphonics mechanical vibrations)have to find the references for this point
Typical Wire Specifications • Diameter: .47 mm (.0185in) • Wire Length: 12m (nominal for cryomodule), (1.2m nominal for bench test setup) • Wire Tension: 18 kg (Provided by weight at one end) • Wire Alloy: Copper- Beryllium • Trade Name: BERYLCO 25 • Alloy: Beryllium: 1.8 – 2.0 % • Co + Ni + Fe: 0.6% max. • Copper: Balance • Density: 8.25 g/cm3 • Tensile Strength: 1260-1440 N/mm2 (depending on heat treating) • Yield Strength: 1090-1330 N/mm2 • Modulus of Elasticity: 131 GPa • Linear Expansion: 17 x 10-6/C0 • Electrical Resistivity: 6.1 – 7.8 x10-6 ohms-cm • Melting Point: 870 – 980 C0 (1600 F0)