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Learning from Babar SVT. 30 April 2003 Toru Tsuboyama (KEK). 5 layers. First and second layer forms a super-layer structure. Third layer is placed slightly away from 1-2 layer. In 1-3 layers, the overlaps between ladders are much smaller than that of Belle SVD.
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Learning from Babar SVT 30 April 2003 Toru Tsuboyama (KEK)
5 layers • First and second layer forms a super-layer structure. • Third layer is placed slightly away from 1-2 layer. • In 1-3 layers, the overlaps between ladders are much smaller than that of Belle SVD. • Fourth and fifth layers are symmetric in r-f view. • Ladders are narrower than Belle SVD. • 16 and 18 ladders in 4th and 5th layer. • Slant sensors are attached.
Geometry optimization sensor types. • No compromise in sensor types • Six types of sensors. • L1, L2 and L3 sensors are of different sizes. • L4 and L5 barrel sensors are of same width. • Two different lengths are used for optimizing the length of ladders. • L4/L5 ladders are narrow. • One wedge type sensor.
Discussions • Are slant sensors really necessary or beneficial? • Slant sensors avoid ladders from becoming too long. • The tracking resolution is determined by the first layer and material in front of it. Effect of slant sensor is not large. • Even tracks in the forward region do not contribute to the vertex resolution significantly, • They will be useful for event reconstruction and (maybe) for online triggers. • To have DSSD sensors is better than to have insensitive material in the detector acceptance.