The V0 detector Mexico Lyon collaboration

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The V0 detector Mexico Lyon collaboration

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box in carbon-fibre. fiber length 5 m. 24 bundles in a duct for 2 sectors. rings 3 and 4 ... arrays, fibre bundles, PMT mechanics. 13. V0 electronics milestones ... – PowerPoint PPT presentation

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Title: The V0 detector Mexico Lyon collaboration

1
The V0 detector (Mexico Lyon collaboration)

Segmentation
Simulated performances
secondaries / beam-gas
Counters
design 1 / design 2
Electronics
pulse treatment / FEE
Milestones
mechanics / electronics

2
Segmentation of the arrays

Two arrays V0A and V0C
2 x 32 channels
segmentation 8 sectors x 4 rings
Pseudo-rapidity windows
?? 0.5-0.6/ring

3
Secondaries

Performances very degraded by
secondaries produced in materials
No optimalization of the V0
for multiplicity measurement
Pb-Pb Hijing events (b lt 11 fm)
correlations Mch of events / Mch
detected by V0 rings
increase of hits by a factor two
4000 MIP across each ring
(8000 across the ring 1 of V0C)
Nevertheles, central and/or
semi-central collisions can be
selected by the FEE on the base
of the total integrated charge
provided by the counters
Efficiency of triggering
83 in pp (inelastic)

4
p-gas background

The V0 should be able to filter
a large part of the p-gas effect
close p-gas Hijing (198 kHz)
halo file used by LHCb (47 kHz)
pp physics Pythia (200 kHz)
Gaussian vertex (5.3 cm) and
time resolution (1 ns)
A cut at 11 ns
rejection depends on the relative
rates of the two components
99 of rejected beam gas in the
present case

5
Counters

Counters made of
2 cm BC404/BC408 scintillator
1 mm BCF9929A(s.c.)/BCF9929A(d.c.) WLS fibres
1.1 mm BCF98(d.c.) optical fibres
Teflon foil as envelope

6
Results

Design 2 applied to V0C elements
2 cm BC408 scintillator
1 mm BCF9929A(s.c.) WLS fibres
5 m of BCF98(d.c.) optical fibres
Present performances (MIP)

Design 1 applied to V0A elements
2 cm BC404 scintillator
1 mm BCF9929A(d.c.) WLS fibres
3 m of BCF98(d.c.) optical fibres
Present performances (MIP)

For the RB26 side, the integration
requires short transition from edge
of counter to clear fibres
Only possible with design 2
Improvement with BC404/BCF(d.c.)?
measures in progress

Design 1 provides a similar network
of fibres to any scintillating track,
whatever its location on the counter is
time fluctuation minimized, better stime
Adapted for large tiles
Adopted for V0A at RB24 side

7
V0A array
all fibres from a sector
fibres gathered in 4 bundles fiber length 3 m
8
V0C array
12 connectors
rings 3 and 4 in 2 pieces to minimize
time fluctuations
9
Electronics

Requirements
MIP dynamic range 1 to 500 with 98 of
acceptance for the MIP
signal dynamic range close to 1000 (minimum of 3
mV achieved)
charge information (0.6 lt Q lt 600 pC), time
(stime lt 1 ns)
Mesh PMT with amplification (shoebox) of the
signal before its transmission (25 m of
Cu-cables) to FEE
FEE 100 of life time
made of three PCBs
CIU charge and time digitization, pre-process
of triggers
CCIU final trigger signal, collection of the
data
TTCIU interface FEE/TTC
Concept finalized by the end of 2004