1 ALICE T0 detector W.H.Trzaska (on behalf of T0 Group) LHCC Comprehensive Review, March 2003.
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Transcript of 1 ALICE T0 detector W.H.Trzaska (on behalf of T0 Group) LHCC Comprehensive Review, March 2003.
1
ALICE T0 detectorALICE T0 detector
W.H.Trzaska
(on behalf of T0 Group)
LHCC Comprehensive Review, March 2003
W.H.T. LHCC Comprehensive Review, March
2003 2
Evolution of Evolution of T0T0 detector concept detector concept
Initial proposal (TP, MoU) one detector does it all (MCP) cost ~1.5 MCHF (Greece,
Russia)
Fall 2000 split of FMD into 3
sub.detectors: Si FMDSi FMD, V0V0 and T0T0 (cost ~200 kCHF)
Spring 2001 Choice of PMT-based T0
(worked-out by a Russian team)
Spring 2002 Finland commits 200 kCHF to T0
and joins the T0 collaboration
W.H.T. LHCC Comprehensive Review, March
2003 3
T0 must work for all ions and for all energy T0 must work for all ions and for all energy densitiesdensities
central
minimum bias
W.H.T. LHCC Comprehensive Review, March
2003 4
Main requirements:Precise timing (50 ps) also on-lineMain LVL0 triggerRough on-line vertex (1.5 cm)Beam – gas suppressionPre-trigger for TDREvent spacing 25 ns (pp)Provide backup for V0 and FMDOperates in the magnetic field (0.5 T)Huge dynamic range (almost 1:1000)
W.H.T. LHCC Comprehensive Review, March
2003 5
T0 – the final configuration:T0 – the final configuration:Two arrays of 12 PMTs with quartz radiators
T0 Right ( + 0.7 m) T0 Left ( - 3.5 m)
Two shoe boxes of fast electronics inside the magnet (+5 m and –5 m)Few creates of electronics outside the magnetLaser calibration system also outside the magnet
W.H.T. LHCC Comprehensive Review, March
2003 6
Output signals:
T0 = (tr+tl)/2+td
T0v = tr-tl (ON/OFF adjustable during run)T0-L, T0-R, CoincTime and energies (all 24 PMTs)3 levels of sum energy Low Medium High
W.H.T. LHCC Comprehensive Review, March
2003 7
T0 LeftT0 Left & & T0 RightT0 Right arrays: arrays: T0 LeftT0 Left & & T0 RightT0 Right arrays: arrays:
T0L -5 < < -4.5
T0R 2.9 < < 3.3
W.H.T. LHCC Comprehensive Review, March
2003 8
Mechanics – T0 Right
W.H.T. LHCC Comprehensive Review, March
2003 9
T0 Left
W.H.T. LHCC Comprehensive Review, March
2003 10
T0-Right 1:1 prototype:T0-Right 1:1 prototype: T0-Right 1:1 prototype:T0-Right 1:1 prototype:
W.H.T. LHCC Comprehensive Review, March
2003 11
Front view:Front view:
W.H.T. LHCC Comprehensive Review, March
2003 12
Back view:Back view:
W.H.T. LHCC Comprehensive Review, March
2003 13
End-cups on the base side:
W.H.T. LHCC Comprehensive Review, March
2003 14
Mounting of the optical fibre (0.4 mm)
W.H.T. LHCC Comprehensive Review, March
2003 15
PiLaserPiLaser400 nmpulse width <40ps roughly 400mW optical peak out of the fibre
W.H.T. LHCC Comprehensive Review, March
2003 16
Possible location of shoe boxes:
Box50 W
Box50 W
12 PMTfull current
<15 W
12 PMTfull current
<15 W
W.H.T. LHCC Comprehensive Review, March
2003 17
Inside the shoe box:
Inside the shoe box:
Am
p1gain=1
Am
p2gain=22
Am
p3ga
in=1
Mul
tiple
xer
D1
D2
Comparetor
output
output
Am
pg
ain
=2
2
Delay R1
R2
Delay
Adder
Dis
cri
min
ato
r 0
Shaper
Comparator
Input
Output
Dual CFDUnit
Dual CFDUnit
W.H.T. LHCC Comprehensive Review, March
2003 18
Characteristics of the Dual CFD Unit
W.H.T. LHCC Comprehensive Review, March
2003 19
Pre-TDR timetable
Production completed by July 2005Fully assembled T0 Tests before shipment to CERN Oct.
2005 Shipment to CERN – November 2005 Final tests – December 2005 Installation in ALICE – March 2006
W.H.T. LHCC Comprehensive Review, March
2003 20
Pre-TDR financing
200 kCHF from Finland Sufficient to cover the detector and
front-end electronics
Readout electronics and integration with DAQ Collaboration with TOF group Greek contribution
W.H.T. LHCC Comprehensive Review, March
2003 21
Highlights of 2002:Highlights of 2002:
Completion of the first draft of TDR (100 pages!)Mechanical prototype of T0 RightFinal multiplicity resolution simulationsElectronic prototypes: Dual CFD Unit (2 prototypes) Mean timer Circuit for generating T0V signal
Choice of laser and the layout of the laser calibration system
W.H.T. LHCC Comprehensive Review, March
2003 22
Still to be chosen:
Final choice of time discriminators(test run @ CERN in July 2003)
Final configuration of readout electronics, DAQ and trigger collaboration with TOF discussions with the Greek team
W.H.T. LHCC Comprehensive Review, March
2003 23
Measured performance of CFDU (JYFL) prototypeMeasured performance of CFDU (JYFL) prototype
5.3 ps/ch
Time walk
-40-20
0204060
1 10 100 1000 10000
Input amplitude [mV]
ps
Time walk
-40-20
0204060
1 10 100 1000 10000
Input amplitude [mV]
ps
Jitter = 25 ps (fwhm)
W.H.T. LHCC Comprehensive Review, March
2003 24
The third option:
CFD DELAY
ADC RAM
RAMlogA
DELAY
T0
TlogA
W.H.T. LHCC Comprehensive Review, March
2003 25
Mean timer prototype
C
1 2 p F
In1
I o
1 5 m A
+V
ECL/NIMDriver
Fastcomparator
I o
1 5 m A
NIM/PECLDriver
In2FastSwitch
FastSwitch
Out
NIM/PECLDriver
W.H.T. LHCC Comprehensive Review, March
2003 26
T0VDC
Fast digitiser for T0V signal
Range of coded time intervals ±2.5 nsDigitisation step 20 ps (for 8-bit)Dead time not more than 25 nsTAC + Flash ADC
W.H.T. LHCC Comprehensive Review, March
2003 27
T0VDC performance
0
50
100
150
200
250
0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00
Delay [ns] vs. channel number
Calibration spectrum
W.H.T. LHCC Comprehensive Review, March
2003 28
Cables and connection from L3
HV cables 2 x 12
Coaxial cables Thresholds 2 x 12 Bunch crossing 2 x 1 Time individual 2 x 12 Output Amplitudes 2 x 12 TRD wake up 2 x 4 T0 right/left 2 x 1
Optical fibre 2 x 12
W.H.T. LHCC Comprehensive Review, March
2003 29
Counting room
Outside the Magnet (~5 m)
Inside the Magnet12 quartz counters
(T0 right)
Two ( left and right ) Constant Fraction Discriminator Units
1 ..................... 12
12 quartz counters(T0 left )
1 ..................... 12
BC
T0rightT0left
T0TRMs(T0 TDC Readout
Module)
Controlbus
T0signalDe-multiplexingcard LTM
(Local TriggerModule)
T0vertexT0signalT0multiplT0busy
1 ....................... 24
DDL
BC
Experimental area(~30 m)F
ast
char
ge
to t
ime
con
vert
or
(FQ
T)
RORC(Read-Out Receiver
Card)
LDC(Local Data
Concentrator)
T0left to TRD
T0right to TRD
De-
mu
ltip
lexi
ng
card
T0TRMs(T0 TDC
Readout Module )
DRM(Data Readout
Module)
BC
General, preliminary readoutscheme for T0:
W.H.T. LHCC Comprehensive Review, March
2003 30
Layout and connections:
....
T0
TR
D
12 quartz counters(T0 right)
Two ( left and right ) Constant Fraction Discriminator Units
12 quartz counters(T0 left )
T0
AR
M
De
-mu
ltip
lex
ing
ca
rd
LTM
Am
plif
ire
s
DR
M
T0
AR
M
Ca
ma
c D
riv
er
VME Redaout Crate VME Local tTirgger Crate
LTU
TT
Cv
i
TT
Ce
x
Sin
gle
Bo
ard
Pro
cc
es
so
r
Camac Control Crate
Ge
ne
rato
r/L
as
er
cin
tro
ller
VD
L &
Ga
tec
on
tro
ller
Ca
ma
c c
rate
co
ntr
olle
r
T0
TR
M...
W.H.T. LHCC Comprehensive Review, March
2003 31
Large change compared to the previous version of PYTHIA:
Efficiency of registration of p-p collisions
0 20 40 60 80 100 120 140 16050
55
60
65
70
75
80
85
90
95
100
Eff
icie
ncy
Multiplicity threshold
L R D