Speaker
Christoph Schwanda
(Austrian Academy of Sciences)
Description
BELLE II is an experiment in KEK ( Tsukuba, Japan ) that will explore heavy flavour physics (
B, charm and tau ) from early 2018 with unprecedented precision. Charged particles are
tracked ( going from the interaction point to the outside ) by a two-layer DEPFET pixel
device ( PXD ), a four-layer silicon strip detector ( SVD ) and the central drift chamber (
CDC ). The design and the construction of the SVD are challenging in many ways: The detector
has about 200k analog channels, which are readout by about 5,000 APV25 ASICs. These frontend
readout chips have a short shaping time of about 50 ns and thus can cope with the backgrounds
expected at Belle II. At the same time, they are sensitive to capacitive noise, which
requires that some of the chips are mounted in the active region of the detector. To minimise
material in the acceptance region, carbon fibre structures and CO2 cooling ( to reduce the
cooling pipe diameter ) are used. In this talk, I will review the design of the Belle II SVD,
the current state of the production and first results on the detector performance obtained in
test beam experiments.
Author
Christoph Schwanda
(Austrian Academy of Sciences)
