Detectors 154
Detectors 154 :
Particle Detectors: (4.15) Hot Wire Barretter: (1) Description and Construction: An extremely fine platinum wire, about 0. 003 inches (0. 08 mm) in diameter, is embedded in the middle of a silver wire having a diameter of about 0. 1 inches (2. 5 mm). This compound wire is then drawn until the silver wire had a diameter of about 0. 002 inches (0. 05 mm); as the platinum wire within it is reduced in the same ratio, it is drawn down to a final diameter of 0. 00006 inches (1. 5 μm). The result is calledWollaston wire. The silver cladding is etched off a short piece of the composite wire, leaving an extremely fine platinum wire; this is supported, on two heavier silver wires, in a loop inside a glass bulb. The leads are taken out through the glass envelope and the whole device is put under vacuum and then sealed
