Post on 02-Jan-2016
description
Status of SVD2 upgrade
Koji Ueno
National Taiwan U.
2003/2/13 @PSROC
Outline
Features of SVD2 Smaller beam pipe & more Si layers TTM( see Jerry’s talk) & Flex: done by NTU.
Flex saga Low yield & spares
Schedule & accident Beam pipe was broken
Conclusion
Features of SVD2
Smaller beam pipe R = 2 cm --> 1.5 cm.Originally 1 cm was planed.
More silicon layers 3 --> 4.Originally 5 layers were planed.
Radiation-hard front-end electronics.Up to 10 MRad is tested OK.
Z trigger.Necessary to remove a beam-gas event.
246 Double-sided Silicon Strip Detectors (DSSDs).
Each DSSD has 512 z strips and512 phi strips.
Total no. read out is 250 k.It is reduced to 110 k by ‘ganging’.
Ganging is done by FLEX.
Belle SVD2
SVD2 system
SVD1.x dose
TTM & Flex
NTU is responsible for TTM & Flex. TTM see Jerry’s talk. We finished them in spring, 2002. They are now used in 1/10 system without
a problem. We need a spare Flex and SVD to prepare
for an “accident”.
Z-R trigger
Efficiency for 3-out-of-4 layers
Ganging in FLEX.
Z strip
DSSD
FLEX
Read outSignal Signal
Wire-bonding onSi and FLEX pads.
Ghost track due to ganging
Flex saga
Flex task was supposedly easy. Flex was in a crisis a year ago: low yield, bad
wire-bonding, repair etc. Laser beam was used to repair shorted lines to
meet a deadline. Only small no. of companies can make a Flex in
the world. Exchange of Flex info. among Belle, D0 and CDF.
Laser surgery of shorted wire
The shorted wire is fixed by laser.
Wire-bonding
25 m wire for bonding.
SVD2 schedule
Integrated luminosity
Peak luminosity of Belle & BaBar
Space Shuttle Columbia accident
SuperKamioka in repair
Broken beam pipe
Installation of 1.2 SVD
Installation of 1.4 SVDHOM resonant heating
Trouble of He cooling system
The SVD2 first cosmic ray muon event
Nov. 15, 2002
Conclusion
SVD2 upgrade has a successful 1/10 system test. Has seen the 1st CR event.
It is likely installed in summer, 2003. It aims for a higher luminosity. We have to prepare a spare SVD and a
spare Flex for an accident.