The KLOE drift chamber

The KLOE drift chamber is a cylinder of ∼2 m radius and ∼3.3 m long, providing an adequate path for KL decays. The tracking volume is surrounded by a 15 X0 em calorimeter and a superconducting coil providing a 0.6T field. Spherical end walls hold the tension of ∼50000 wires, with good transparency, ≤0.1 X0, to photons from π0 decays. Alternating stereo wires only, with constant radial displacement at the center, provide a uniform filling with approximately square cells. A HeiC4H10 gas mixture and Al field wires are used to minimize multiple scattering. The chamber point resolution in r, φ is significantly better than 200 μm resulting in a KL → π+π− vertex accuracy of σx,y(z) ≤ 0.5(1–2) mm. The K0 mass resolution is σM ∼ 1 MeV/c2.