LHCb VErtex LOcator
For precision measurements of CP-violation at CERN (GENEVE)
HALF of DETECTOR
Si strip
detector
Secondary vacuum container
Read-out
electronics
Vacuum vessel
Exit foil
Vacuum pump
Prototype foil of the
Secondary vacuum container
Technical
Proposal
Start
Prototyping
work
1998
1999
Technical
Design
Report
2000
2001
Design
Start
Review production
2002
2003
SILICON MODULE
Installation in the
LHCb experimental area
2004
2005
PROJECT DESCRIPTION:
VErtex
LOcator
LHC-b detector
Design and production of the Silicon VErtex LOcator for the LHCb experiment at CERN.
During collisions of the two proton beams in the 'Large Hadron Collider' (LHC) B-mesons will be
produced. The decay of these B-mesons is not invariant under Charge and Parity reversal: they
show CP-violation.
The B-mesons travel about 7 mm before decaying into other particles. The micro vertex has been
designed to do an accurate measurement of the decay position (vertex) of these B-mesons.
The VErtex LOcator consists of a row of silicon detectors, each 0.3 mm thick. Charged particles that
traverse the silicons generate an electrical charge which can be measured. The silicons are
positioned perpendicular to the proton beam at a radial distance of 8 mm from the beam. To be close
to the proton proton interaction and with a minimum amount of material in front, the sensors have to
be placed in a secondary vacuum box
During the filling and ramping of the LHC ring the detectors have to moved out by 30 mm in order to
prevent radiation damage. For the actual measurements they have to be moved in again with a
position accuracy of 0.05 mm.
The whole VErtex LOcator is placed inside the vacuum system. The detectors and the read-out
electronics are constructed from radiation hard components. The heat produced by the electronics is
taken care of by a cooling system that uses CO2 as refrigerant. The signals from the detector are
transported outside the vacuum system for further analysis through 22,000 signal cables.
PROJECT GROUPS :
NIKHEF, VU (The Netherlands), Liverpool University (UK), CERN,
Lausanne University (Switzerland), ASIC lab. University Heidelberg (Germany)
VErtex LOcator
www.nikhef.nl/pub/experiments/bfys/lhcb/vertex/