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LHCC, V0, Sept. 2004 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
V0A
V0C
LHCC, V0, Sept. 2004 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
V0A V0CRing
1 5.1/4.5 -3.7/-3.2
Ring 2 4.5/3.9 -3.2/-2.7
Ring 3 3.9/3.4 -2.7/-2.2
Ring 4 3.4/2.8 -2.2/-1.7
LHCC, V0, Sept. 2004 3
Secondaries Performances very degraded by secondaries produced in materials No optimalization of the V0 for multiplicity measurement Pb-Pb Hijing events (b < 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)
V0A
V0C
LHCC, V0, Sept. 2004 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
LHCC, V0, Sept. 2004 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
Design 1
PM
Teflon foil
connector WLS fibres
optical fibres
Design 2
connector
PM
Teflon foil
WLS fibres
optical fibres
6
Results 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):
Design 1 provides a similar network of fibres to any scintillating track, whatever its location on the counter is• time fluctuation minimized, better σtime Adapted for large tiles Adopted for V0A at RB24 side
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):
500 – 600 ps
28 – 34 – 42 p.e.
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
80020
optical fibre
LHCC, V0, Sept. 2004 7
V0A array
connector bar
PM
all fibres from a sector
fibres gathered in 4 bundlesfiber length 3 m
8
V0C array
box in carbon-fibre
fiber length 5 m24 bundles in a duct for 2 sectors
rings 3 and 4in 2 pieces to minimize timefluctuations
12 connectors
LHCC, V0, Sept. 2004 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 < Q < 600 pC), time (σtime < 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
LHCC, V0, Sept. 2004 10
CIU board data from V0C
V0A
BBA (BBC)
BGA (BBC)BBA (BGC)
X 4 HPTDC (8 ch/chip)
dataL1 buff
buffer
data from V0A
L2
DAQ
L0
hit
ADC
ADC
DISC.
DISC.
THR
buffer
buffer
bufferbuffer
individual offsetcompensation
adjustable windows(step of 20 ps, range of 10 ns)
adjustable windows (.5 to 12 ns, step of .5 ns)
programmableintegration gate width
(from 3 ns to 36 ns, 3 ns step)
+1 sum foreach ring
+
+
FPGA4
4
from V0C
1 sum for
each ring4
4from V0C
1 sum for
each ring4
4from V0C
programmable thresholds
BC
4
5 triggers, eg :- minimum bias- beam/gaz (right)- beam/gaz (left)- multiplicity- centrality
x 3
2 a
nodes
time
BB MB triggers
centrality triggers
THRcharge
THRmult
.
BGA BGC(V0C)
BG MB triggers
multiplicity triggers
chargelow M
DAQ
charge
L0
L0
LHCC, V0, Sept. 2004 11
Minimum-bias triggers Starting from the discriminator signal BB signal detected in time windows centered at +11 ns (V0A) and +3 ns (V0C)
BGA signal detected in time windows centered at -11 ns (V0A) and +3 ns (V0C) BGC signal detected in time windows centered at +11 ns (V0A) and -3 ns (V0C)
V0A
DISC.
DISC.
THR
buffer
buffer
adjustable windows(step of 20 ps, range of 10 ns)
adjustable windows (.5 to 12 ns, step of .5 ns)
BGA
BBA
+
+1 sum for
each ring4
1 sum for
each ring4
x 3
2 a
nodes
l t
BGC
BBC
+
+
-11 ns
+11 ns
V0C
-3 ns
+3 ns
ABGCBGA
C&
BB
bbc
bba
C&
Multiplicity trigger
A
THRmult
.
12
V0 mechanics milestones• End 2004:
• March 2005: sector ‘0’ of V0A (Mexico) and V0C (Lyon) (construction
and test) PRR submission• October 2005: V0C commissioning, PMT characterization (Lyon)
• End 2005: V0A commissioning, PMT characterization (Mexico) • April 2006: • June 2006: V0C installation in ALICE
• End 2006: V0A installation in ALICE
Responsibles: Mechanics: J.Y. Grossiord (Lyon), XXXX (Mexico)
p.e./MIP PMTgain
arrays, fibre bundles, PMT mechanics
13
V0 electronics milestones• End 2004: electronics concept finalization (PMT, ‘shoebox’, FEE) CIU design prototype test• March 2005: • October 2005: CCIU and TTCIU design prototype test PRR submission• End 2005: CIU, CCIU, TTCIU electronic scheme• April 2006: electronics design ready for realization• June 2006: electronics construction• End 2006: electronics test, calibration, connection to CTP electronics ready for installation in ALICE
Responsibles: Electronics: Y. Zoccarato
14
V0 milestones• End 2004: electronics concept finalization (PMT, ‘shoebox’, FEE) CIU design prototype test • March 2005: sector ‘0’ of V0A (Mexico) and V0C (Lyon) PRR submission• October 2005: V0C commissioning, PMT characterization (Lyon) CCIU and TTCIU design prototype test PRR submission• End 2005: V0A commissioning, PMT characterization (Mexico) CIU, CCIU, TTCIU electronic scheme• April 2006: electronics design ready for realization• June 2006: V0C installation in ALICE electronics construction• End 2006: V0A installation in ALICE electronics test, calibration, connection to CTP electronics ready for installation in ALICE
Responsibles: Electronics: Y. Zoccarato Mechanics: J.Y. Grossiord (Lyon), XXXX (Mexico)
15
label total pricePM R5946 + HV 200000
Electronics + VME 120000V0A + V0C +
cabling 45000Total in SF 365000
V0 cost