The Belle Silicon Vertex Detector

The Belle Silicon Vertex Detector (SVD) was designed to measure B meson decay positions precisely for studies of time-dependent CP violation. Although the first version of SVD (SVD1) worked for 4 years from 1999 with excellent performance, its insufficient radiation hardness drove us to build a second generation SVD (SVD2). The SVD2 was installed in Belle in the summer of 2003 and has been working well. The strip yield is estimated to be more than 95%. The signal-to-noise ratios are obtained to be 18–36, depending on detector ladders. The intrinsic spatial resolutions are obtained to be 12.0 ± 0.4 and 22.3 ± 0.8 μ m for φ - and z-sides, where z-side measures positions along the beam direction and φ side is used for the azimuthal angle measurement. In this letter, an overview and performance results are provided for both generations of the Belle SVD.