PERFORMANCE OF THE NEW VERTEX DETECTOR AT SLD

During the past year, the SLD collaboration completed the construction and began the operation of a new vertex detector (VXD3) employing 307 million pixels. This detector, based on 96 CCDs of 13 cm(2) area each , is an upgrade of the original vertex detector of SLD (VXD2), made po ssible by advances in the technology of CCD detectors. Its improved im pact parameter resolution, larger solid angle coverage and virtually e rror0free track linking will enhance the SLD measurement of the polari zation-enhanced forward-backward asymmetry for band c- quarks, increas e the precision of the measurement of the b-fraction in hadronic Z dec ays, and open the possibility to observe B-5(0)-mixing. Full separatio n of primary, secondary and tertiary vertices is accessible. A descrip tion of the mechanics and electronics of VXD3 are presented along with results from the first data.