Transcript Document

Review of the CMS
muon detector system

Physics goals

Muon system layout

Barrel Drift Tubes Chambers (DT)

Endcap Cathode Strip Chambers (CSC)

Resistive Plate Chambers (RPC)

Installation

Conclusions
8th Topical Seminar on Innovative Particle and Radiation Detectors
Ezio Torassa – Sez. INFN di Padova
Siena, 21-24 October 2002
Physics goals
The 4 lepton channel is the most promising for SM Higgs 130  mH  650 GeV
Siena, 21-24/10/2002
Ezio Torassa, INFN Padova
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Physics goals
• H g Z Z(*) g 4 m
SM Higgs
(mass resol. ~ 1 GeV)
• h, H, A g m+ m-
SUSY Higgs
(mass resol. ~ 1 GeV)
•~
q,~
g g multi-lepton + multi-jet + Etmiss
Superpartners
(muon recognition in multi-jet environment)
• Z’ g m+ m-
New Gauge Bosons
(Pt m measur. and sign determ. Above 1TeV)
• etc …
Siena, 21-24/10/2002
Ezio Torassa, INFN Padova
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Muon system layout
Endcap: 4 disks 2-3 wheels
Siena, 21-24/10/2002
Barrel: 5 wheels
Ezio Torassa, INFN Padova
4 shells
12 sectors
4
Muon system layout
Barrel (<1.3) DT - RPC
Endcap ( 0.9<<2.4) CSC - RPC
• particle rates < 10 Hz/cm2
• particle rates 10-100 Hz/cm2
• low B field < 0.8 T
• high B field up to 3 T
RPC goals
Measure f points along muons track
segments in the barrel and endcap regions
to:
• identify muons and assign a bunch crossing
• estimate their pt
1 track segment with 6 f points
Efficiency > 95% Time resolution  3 nsec
Siena, 21-24/10/2002
Ezio Torassa, INFN Padova
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Muon system layout
DT goals
Measure f and  points along muons track segements in the barrel region to:
• identify muons and measure charge and momentum
• identify the bunch crossing associated to every muon track
4 track segment with 8 f and 4  points
single point resol. ~ 250 mm  track segments precision of 100 m m 
 under multiple scattering contribution up to pt = 200 GeV
CSC goals
Like DT but in endcap regions
4 track segment with 6 f and 6 R points
single point resol.  120 - 250 mm
track segment precision  75 mm Disk 1 Sectors 1,2 (150 m m Disk 2,3,4) 
 under multiple scattering contribution up to pt = 100 GeV
Siena, 21-24/10/2002
Ezio Torassa, INFN Padova
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Barrel Drift Tubes Chambers
DT Chambers
Production sharing
5
4
3
2
6
1
7
12
8
9
10
11
Aachen
Madrid
Padova
Torino
10 Sectors will be installed in SX5
210 Chambers(420 RPCs).
Sectors 1 and 7 are used for the
lowering fixture and will be installed in UX5
40 Chambers(80 RPCs).
Siena, 21-24/10/2002
# chambers
70
70
70
40
(Bologna, Dubna and Protvino)
Ezio Torassa, INFN Padova
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Barrel Drift Tubes Chambers
Chamber

250 Chambers
172200 Anode ch.
Superlayer
Siena, 21-24/10/2002
Ezio Torassa, INFN Padova
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Barrel Drift Tubes Chambers
Drift Tube
42mm
Wire
Electrode Strip
13 mm
Mylar
Drift velocity mm/ns
Cathode Al Strips
Cell designed to have electric
field as uniform as possible

Gas mixture Ar/CO2 ( 85/15 % )
Vc / Vs / Vw = -1.2/+1.8/+3.6 (kV)

E = 1 - 2 kV/cm
Electric field kV/cm
Siena, 21-24/10/2002
Ezio Torassa, INFN Padova
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Barrel Drift Tubes Chambers
DT performance: last prototype with muon beam
Results from July 1999
CERN-H2 test beam
Single cell resol.  170 mm
The prototype is a narrow MB2 type
superlayer with the final cell design
( 3 nsec)
Single cell efficiency  99.8 %
(1% geometrical ineff. removed)
Siena, 21-24/10/2002
Ezio Torassa, INFN Padova
Performance confirmed
in the Sept. 2001 test
beam using the first DT
chamber. A new test
beam is foreseen in
March 2003
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Barrel Drift Tubes Chambers
DT Chamber Production (18DT/site/year)
50
Start: 04/2001
End: 09/2005
45
40
35
180
# SL
# Chambers (all sites)
230
130
80
45/56
Planned
Achieved
Shortage
SL phi
SL phi


SL phi


Madrid
Padova
Aachen
30
SL theta Madrid



SL theta Padova



SL theta Aachen



25
Torino starts March 2003
20
15
10
30
5
-20
4/1 1/2 2/2 3/2 4/2 1/3 2/3 3/3 4/3 1/4 2/4 3/4 4/4 1/5 2/5 3/5
0
gen-01
gen-02
gen-03
4/1 = end Q4 2001, 1/2 = end Q1 2002 etc ..
14 chambers at CERN (ISR) under HV , 32 chambers within November 5th
Siena, 21-24/10/2002
Ezio Torassa, INFN Padova
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Barrel Drift Tubes Chambers
Construction check list
Tool Maintenance check list
Electronic install. check list
Chamber test check list
Drift tubes quality control manual and procedures V7
AACHEN
CIEMAT
Wire:
tension and position
SL:
HV and gas tightness
Chamber, SL:
thickness, flatness
Every channel:
noise, eff. and resolution
www.pd.infn.it/dbcms/db
Database
TORINO
LEGNAROwww.physik.rwth-aachen.de/~dbac/
Siena, 21-24/10/2002
wwae.ciemat.es/cms/ChamberConsDb/db.html
Ezio Torassa, INFN Padova
Padova
Aachen
Madrid
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Barrel Drift Tubes Chambers
TIME CONSTANTS
Gas tightness
10000
Pressure drop:
1
 Pi 0  Pa 
  t / ln

 Pi  Pa 
#Chamber
3
Min
1 125
277

2 35
>135 min
> 1000 min
Dead-Noisy channels
100
1
Number
Now 

2hours
10
Pi = pressure at t=0
Pa = pressure after t>0
QC requirement:

2
1000
5
40
50
25
20
50
70

7
8
9
10
10
115 3000 280 500 1419
150 58 2300 150 7000
800 350 7000 525 727
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TOT
FE problems
Half Ibeams
HV Cell discon
1%
8
Noisy cell: Freq. > 500 Hz/cell
4
6
Noisy cells + Disconn. Cells < 1%
4
2
0
Siena, 21-24/10/2002
2
3
4
Ezio Torassa, INFN Padova
5
6
Chamber
7
8
9
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Barrel Drift Tubes Chambers
DT full production tested with cosmic rays
Typical TDC
spectrum for
one cell
tmax =370 ns
Meantime= dist (1)  dist (3)  dist (2)
1
2
vdrift  57 mm/ns
Meantime r.m.s.  400 mm (7 nsec)
Efficiency ~ 99%
Probability for a
4.hit on a track
Mean
time
resol. = 2/3 r.m.s.  325 mm
Siena, 21-24/10/2002
Ezio Torassa, INFN Padova
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Barrel Drift Tubes Chambers
4 tech. + supervisor , half a day/ch
Siena, 21-24/10/2002
Ezio Torassa, INFN Padova
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Endcap Cathode Strip Chambers
36 sectors
# Chambers
72
JINR (Dubna)
144
IHEP (Beijing)
72
(108)
PNPI (Petersburg)
144
(216)
FNAL, UF and UC
18 sectors
ME 4
ME 3 ME 2
ME 1
staged
Siena, 21-24/10/2002
Ezio Torassa, INFN Padova
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Endcap Cathode Strip Chambers
540 (432*) Chambers
4 disks
2-3 rings
(3 for ME1)
~ 2.5 million wires
210816 Anode ch.
273024 Cathode ch.
(*)(ME4
Chamber Trapezoidal shape
covers 10o or 20o sectors
Siena, 21-24/10/2002
staged)
Each Chamber has 6 gas gap
planes
Ezio Torassa, INFN Padova
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Endcap Cathode Strip Chambers
9.5 mm
CSC gas gap plane is a multiwire proportional chamber
3.2 mm
H.V. wires 3.6 kV (Qcath.  110 fC, Qanode  140 fC)
Wires measure r-coordinate
Wires spaced by 3.2 mm ganged in groups of 5-16
Strips run radially to measure f coordinate
3 - 16 mm
Strips width 3-16 mm
Gas mixture Ar/CO2/CF4 ( 40/50/10 % )
Siena, 21-24/10/2002
Ezio Torassa, INFN Padova
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Endcap Cathode Strip Chambers
Chamber production status (25 September 2002):
33 / 72 JINR
58 / 144 IHEP
36 / 72 PNPI
110 / 144 Fermilab
Start:
05/2000
End:
06/2003
UF, UC
20 chambers
shipped to CERN
Siena, 21-24/10/2002
Ezio Torassa, INFN Padova
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Endcap Cathode Strip Chambers
Siena, 21-24/10/2002
Ezio Torassa, INFN Padova
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Resistive Plate Chambers
Italy: Bari, GT
(Naples, Pavia)
China: Beijing
Bakelite production
and quality control
Mechanics for RB1
RB1 Assembly and test
Gap production and
quality control
First two wheels assembled in Italy
Front-end production
RB2, RB4 assembly and test
RB4, 120 chambers
RB3, 120 chambers
Bulgaria: Sofia
RB2, 120 chambers
Mechanics for RB2, RB3, RB4
RB1, 120 chambers
RB3 Assembly and test
Siena, 21-24/10/2002
Ezio Torassa, INFN Padova
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Resistive Plate Chambers
China
Korea
The engineering design is ready. EDR in October.
Pakistan
RE1/2 RE1/3 RE3/2 RE3/3 RE4/2 staged
R E * /3
R E * /2
No. of chambers
R E * /3
R E * /2
RE
RE
RE
R
E
*
/
1
1/1
1/2
1/3
36*2 36*2 36*2
Siena, 21-24/10/2002
RE
2/1
18*2
RE
2/2
36*2
RE
2/3
36*2
Ezio Torassa, INFN Padova
RE
3/1
18*2
RE
3/2
36*2
RE
3/3
36*2
RE
4/1
18*2
RE
4/2
36*2
22
RE
4/3
36*2
Resistive Plate Chambers
RPC double gap module
Avalanche created inside the gap, charge induced on strips
(Avalanche operation mode can work with higher rates w.r.t. streamer mode)
Resistive electrodes prevents surface
sparking damages
Electrode resistivity
Rate capability
Vdrop  rate • electrode
Gap width
• Operating H.V.
• Gap width
Double gap improves
efficiency and time
resolution
 9.0 kV
2 mm
• Bakelite bulk resistivity
1-2 1010 W cm
• Bakelite thickness
2 mm
• strip width
~ 35 mm
• Gas
Siena, 21-24/10/2002
Time performance
95% C2H2F4 , 5% i-C4 H10
Ezio Torassa, INFN Padova
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Resistive Plate Chambers
Schedule for wheel # 0:
25 RB3 => end September 2002
25 RB1 => end January 2003
25 RB2 => end March 2003
25 RB4 => April 2003
From the beginning of 2003
Production rate: 10 chamber/month
Test rate:
15 chamber/month
First wheel
by the end April 2003
Second wheel by the begin of 2004
Production rate: 12 chamber/month
Start to assembly RE1/2 and RE1/3
Siena, 21-24/10/2002
Ezio Torassa, INFN Padova
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Resistive Plate Chambers
RPC tested with cosmic rays
Efficiency
Current
Noise
Siena, 21-24/10/2002
Ezio Torassa, INFN Padova
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Installation
12 MB1 24 RE1
12 MB2 24 RE2
12 MB3 24 RE3
6 MB4 12 RE4
Installation windows for MB V33
Installation
Cabling
Siena, 21-24/10/2002
Ezio Torassa, INFN Padova
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Conclusions
•
CMS muon system has been designed to achieve
the LHC physics goals
•
Required performances were obtained with
detector prototypes and were confirmed with the
produced chambers
• The production status is: DT 18%, CSC 55%, RPCB 4%
the small shortage w.r.t. the planning is compatible
with the installation planning
Siena, 21-24/10/2002
Ezio Torassa, INFN Padova
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