1. Validation and Performance
A. Meneguzzo
Padova University & INFN
Validation and Performance
of the CMS Barrel Muon Drift Chambers with Cosmic Rays
Cosmic rays are free, have no schedule ,
illuminate uniformly, are in all production sites.....
Each chamber of the Barrel Muon System of the CMS experiment equipped with the final front-end and Low and High Voltage boards is fully tested in each assembly site in a cosmic rays facility. The system allows to check in real time the perfomances and the quality of the chambers and of the local trigger devices.The behaviour of the chambers built in the Legnaro INFN National Lab is reported and compared with Test Beam results.
ICATPP 2003
Como october, 2003

2. 30o sectors with 4 stations
Barrel muon system
V.Monaco – INFN Torino
8th IACTPP Conference, Como 6-10 October 2003
5 wheels
30o sectors with 4 stations
250 DT chambers
2.0x2.5 m2 (MB1)
4.0x2.5 m2 (MB4)
~2*105 channels
480 RPC chambers
MB4
MB3
MB2
MB1
ICATPP 2003
Como october, 2003

3. CMS Drift Tube Chambers
“SuperLayer” (SL 2)
(coord. in bending plane)
SL  (non-bending plane)
honeycomb panel
SL 1
30 cm
Within one SL 4 layers staggered by half a cell to solve L/R ambiguity tA tB tC tD A
42mm
continuous lines represent electrodes
dotted lines represent equipotential surfaces S g C W s a b
b/a ~ .65
13mm
42mm S S B
13mm
13mm C g g s s W W a a b b
b/a ~ .65
b/a ~ .65 D
continuous lines represent electrodes
dotted lines represent equipotential surfaces
continuous lines represent electrodes
dotted lines represent equipotential surfaces
ICATPP 2003
Como october, 2003

4. Muon system specifications
V.Monaco – INFN Torino
8th IACTPP Conference, Como 6-10 October 2003
Muon identification
(after >10  up to   2.4)
Standalone momentum measurement
Charge assignement
(up to few TeV)
Trigger on single and
di-muons with variable
Pt threshold up to 2.1
Bunch crossing
assignment
ICATPP 2003
Como october, 2003

5. Laboratori Nazionali di Legnaro (padova): DT chambers construction
glue for I-beam
LNL
HV & LV boards
Final chamber
ICATPP 2003
Como october, 2003

6. Barrel Muon : DT chamber requirements
First Level Trigger
(Mean time technique on staggered layers)
Bunch crossing identification
Track segment reconstruction
Pt cut : sharp efficiency curve
drift time vs position linearity in the cell
100mm precision on wire position within a SL
<1mm between f SL
Muon track parameter
muon ID coverage up to IhI=1.1
- momentum & charge assignement
Resolution of 250mm/cell
Max Efficiency
Minimum Noise level
Noise
Efficiency
Resolution
Wire and Layer position accuracy
SL F position accuracy
we want to measure for each chamber
ICATPP 2003
Como october, 2003

7. Chambers and Trigger set up at LNL
Chamber under test
Chamber under trigger test
Local Trigger CCB
Cosmic Rays : trigger set-up
ICATPP 2003
Como october, 2003

8. Monitor and analysis SET UP
The DAQ system is developed within the TRIDAS project; it has been used in the Test Beam 2000 , 2001, 2003 and at ISR (stoking area for final checks of all DT chambers) G.Maron et al. LNL
Data Base Objectivity
Flat File N.Toniolo LNL
Analisys Off-line:
-track reconstruction
-trigger emulator
-ntuples production with
raw data and tracks information
ORCA framework P.Ronchese et al., Pd
MONITOR :on line analysis
–occupancy
-noise
-efficiency
-MT
-Event Display
ORCA framework Sara.Vanini et al., PD
ICATPP 2003
Como october, 2003

9. Cell and drift time distribution checks
1800 V
Strips
3600V
good
-1200 V
bad but it can be recovered
Drift time
Bad cathod
ICATPP 2003
Como october, 2003

10. Noise Noise of the channels in all layers of a chamber of all chambers
20 Hz/m
channel
ICATPP 2003
Como october, 2003

11. Noise vs Hv and noise vs Th
Noise vs HV on the wire
Noise vs FrontEnd Threshold
ICATPP 2003
Como october, 2003

12. cell efficiency in the layer efficiency inside the cell
geometrical inefficiency 1.2/42= 3% for normal tracks
I-beam
wire
1.00
0.96
ICATPP 2003
Como october, 2003

13. Efficiency :angle & all chambers
Dead angle= 90
98%
99%
Mean SL Efficiency
for the first 12 chambers
ICATPP 2003
Como october, 2003

14. Efficiency :diagnostic
Efficiency in a layer :last 8 cells low efficiency
Efficiency as a function
of position inside the cells
No voltage on the cathods
ICATPP 2003
Como october, 2003

15. Mean time fit with ‘time’y t4 t3 t2 t1
d staggering t4 t3 t2
21000/ 380ns
Vdrift=55mm/ns t1
d staggering
semicolumn
s= 1.6ns Wire position accuracy~70mm
From the MeanTime distribution of the tracks in each semicolumn (semicell) we measure
-the wire position accuracy from the width of the distribution of the Mean
-the resolution and the resolution uniformity of the cells along the layer and in the SL
Resolution=250mm
Resolution smt=sqrt((s2-s trig_pm2) =3/2sl2
ICATPP 2003
Como october, 2003

16. MT: Layer displacement
Example: layer 4 displaced of dx Dt Dt t4 t4 t4 t4 t3 t3 t3 t3
Dt = ( MT234R- MT234L) using the mean value of all MT234 ->good accuracy
Layer 4 displacement -> Dx =Dt * vdrift t2 t2 t2 t2 t1 t1 t1 t1
d staggering
d staggering
d staggering
d staggering
Mean 378 ns
Mean 383 ns
ICATPP 2003
Como october, 2003

17. MT : signal wire propagation
Measurement of the signal propagation along the wire
vsignal=0.244 m/ns
FEside
vdrift=21/378=0.55mm/ns
ICATPP 2003
Como october, 2003

18. MT summary s=1.7 ns =>> 66 mm Resolution in the cell
Drift velocity in the cell
Accuracy on staggering and wire position
s=1.7 ns =>> mm
For all chambers
ICATPP 2003
Como october, 2003

19. MT vs angle
The apparent drift velocity grows with y angle;it is constant for q
F angle
q angle
ICATPP 2003
Como october, 2003

20. F Super Layers alignment
All 4 point tracks, |f| < 20o
62215 mm
build 4 point segment
in each single SL
MB3_12 x2
Extrapolate to the
middle plane of the chamber x1
-3.80.1 mrad
before alignment corrections
ICATPP 2003
Como october, 2003

21. Layer alignement : 7 point fit residuals
<>=-1755 mm
SL f1
<>=205 mm
MB3_12
<>=395 mm
SL f2
<>=655 mm
ICATPP 2003
Como october, 2003

22. C2 fit vs SLs displacement
c2 / NDOF
all but one layer included
(before layer alignment)
8515 mm
Layer 1
excluded
before layer
alignment
-0.50.1 mrad
all layers
included
after layer
alignment
after alignment corrections
ICATPP 2003
Como october, 2003

23. DT Chamber performance in Test Beam
Hit rate in SL1 is
3.5 (1.7 for SL 2)
larger than the
worst case at LHC
(shown SL1)
MB2 :TEST BEAM 2001 Resolution and
Plateau knee
192
micron
Drift cell effic.&resolution
With increasing Background
CMS Note 2003/007
192
micron
ICATPP 2003
Como october, 2003

24. DT Chambers: 1st Level Trigger
SL2 BTI outer
SL1 BTI inner
H 4 points track
L 3 points track * H L
HL (LH) N Ho Hi
BTI outer
BTI inner HH
TRACO
TSS/TSM
ICATPP 2003
Como october, 2003

25. First Level Trigger set-up: functionality tests with cosmic rays
The first final set up of the First Level Trigger has been tested on a MB3 chamber with a muon bunched beam at Cern in may 2003 (the test was successfully and preliminary results show perfect behaviour). The set up was first assembled and its functionaly checked at the assembly site in LNL. Here I presents the on line results of these first preliminary tests that showed us that the set up was correctly working. The real performance of the 1st Level Trigger have been studied on the test beam run and will come out soon. (Results of the performance of the BTI part of the 1st Level Trigger from Test Beam and with Magnetic field are in the CMS note01-051)
output triggers with 3(L) or 4(H) hits trigger tracks in each SL ->correlated trigger
Bunch crossing identification
Angle trigger
-450
450
Angle track
ICATPP 2003
Como october, 2003

26. Bunched TB 2003 DTchamberTriggerPreliminary
trig. at 14bx
efficiency =
total # of events
Event= scintillator + 2 hits in beam region
trig. at 14bx
efficiency =
total # of events
Event= scintillator + 2 hits in beam region
trig. at
efficiency =
total # of events
Event= scintillator + 2 hits in beam region
trig. at 14bx
efficiency =
total # of events
Event= scintillator + 2 hits in beam region
trig. at 14bx
efficiency =
total # of events
Event= scintillator + 2 hits in beam region
tracks hitting 2 I-beams
tracks hitting 2 I-beams
tracks hitting 2 I-beams
tracks hitting 2 I-beams
tracks hitting 2 I-beams
Preliminary DT Trigger Performance - Sara Vanini SIF 2003
~ %
efficiency up to 350
~ %
efficiency up to 350
~ %
efficiency up to 350
~ %
efficiency up to 350
~ %
efficiency up to 350
“EMULATOR” is a SW package that emulates the full chain of the Trigger
Chips and Boards. It works offline and need as input the times recorded
by the TDCs. “Emulator “ is not the CMS simulation,it should reproduce exactly
the Trigger data. To compare with the expected performance as shown in the
Trigger TDR we should compare with the full track reconstruction from TDC data.
However this first result is in excellent agreement with what we expect.
“EMULATOR” is a SW package that emulates the full chain of the Trigger
Chips and Boards. It works offline and need as input the times recorded
by the TDCs. “Emulator “ is not the CMS simulation,it should reproduce exactly
the Trigger data. To compare with the expected performance as shown in the
Trigger TDR we should compare with the full track reconstruction from TDC data.
However this first result is in excellent agreement with what we expect.
“EMULATOR” is a SW package that emulates the full chain of the Trigger
Chips and Boards. It works offline and need as input the times recorded
by the TDCs. “Emulator “ is not the CMS simulation,it should reproduce exactly
the Trigger data. To compare with the expected performance as shown in the
Trigger TDR we should compare with the full track reconstruction from TDC data.
However this first result is in excellent agreement with what we expect.
“EMULATOR” is a SW package that emulates the full chain of the Trigger
Chips and Boards. It works offline and need as input the times recorded
by the TDCs. “Emulator “ is not the CMS simulation,it should reproduce exactly
the Trigger data. To compare with the expected performance as shown in the
Trigger TDR we should compare with the full track reconstruction from TDC data.
However this first result is in excellent agreement with what we expect.
“EMULATOR” is a SW package that emulates the full chain of the Trigger
Chips and Boards. It works offline and need as input the times recorded
by the TDCs. “Emulator “ is not the CMS simulation,it should reproduce exactly
the Trigger data. To compare with the expected performance as shown in the
Trigger TDR we should compare with the full track reconstruction from TDC data.
However this first result is in excellent agreement with what we expect.
ICATPP 2003
Como october, 2003

27. CONCLUSIONs
The results of the tests performed in the production site with Cosmic Rays of each Barrel Muon Drift Chamber of the CMS experiment are very good and confirms the 2000(cms note01-051) ,2001 (cms note03-07) and 2003 Test Beam results:
Noise <25 Hz/m
Efficiency uniform % / layer
cell
layer
vs phi angle
vs theta angle
Resolution ~ 250m/cell 100m/SL
Mean Time: cell
phi angle
theta angle
Layer position accuracy < 110 m all Layers/SL
SLs F position accuracy < 1mm
linear fit
Trigger tests with cosmic good
Cosmic rays are free, have no schedule , illuminate uniformly, are in all production sites.
ICATPP 2003
Como october, 2003

28. help1 The Installation Task
The Barrel Muon system comprises 250 chambers in 7 flavors:
60 MB1 3SL 2 RPC ~2.0 x 2.54 m kg
60 MB2 3SL 2 RPC ~2.5 x 2.54 m kg
60 MB3 3SL 1 RPC ~3.0 x 2.54 m kg
40 MB4 2SL 1 RPC ~4.2 x 2.54 m kg
10 MB1 2SL 1 RPC
10 MB2 2SL 1 RPC
10 MB3 2SL 1 RPC 4 5 3 6 2 1 7 12 8 11 9 10
F SL
SL
Honeycomb
MB4 (Torino)
Have two Superlayers only
F SL
10 Sectors will be installed in SX5 => 210 Chambers(310 RPCs). Sectors 1 and 7 are used for the lowering fixture and will be installed in UX5 => 40 Chambers(60 RPCs).
ICATPP 2003
Como october, 2003

29. 42 mm
Help cell
continuous lines represent electrodes dotted lines represent equipotential surfaces S g C W s a b
b/a ~ .65
13mm
the position of the s equipotential depends
on the cell geometry (i.e. on the strip width
and on the wire radius)
Vw-Vs determines the GAIN in the gas :
the request of a gain of ~ 10^5 determines
the position of the s equipotential to be
~ 2.5 mm from the wire
the presence of the grounded Al plates and
beams between S and C makes the position
of the g equipotential quite independent of
the Voltages of s and c
Vc ( and Vs) must generate in the region
between c and g ( and between g and s )
an E field between 1 and 2 KV/cm to
saturate the drift velocity
ICATPP 2003
Como october, 2003
LHCC Comprehensive Review 10/2/ CMS MUONS: Drift Tubes and Alignment fabrizio

30. Help schedule LNL 5/9/2003 96 SL 32 CH Aachen 15/8 102 SL 34
Madrid 10/ SL CH
100 ch out of 210
Chambers at ISR MB by dec MB MB
Total
These figures can imply that all the dressing will be done for all
chambers at ISR (to be agreed)
ICATPP 2003
Como october, 2003

31. Help BTI * * a a * * * Shift registers * b * * a +b = T ICATPP 2003
Como october, 2003

32. Help ISR
ICATPP 2003
Como october, 2003

33. BX Efficiency -2 Help TB2003 Traco CCB HH HL LL
drop of correlated efficiency at large angles due to geometrical cuts (single BTI 56o traco 42o)
Ho Hi Lo Li 15
DT Trigger Performance - Sara Vanini

34. Help TB2000 BTI
BTI test in Magnetic Field (test beam 2000, CMS note 2001/051)
.05 .1
.16
.21
.26 BW
.38
.56
.77
.96
1.15 Bn
.19
Prob. of one/4 layers affected by delta 16%, more than one 4%
B (TESLA) longitudinal component
CMS TN
.31
H-trig = 4/4 layers
L-trig = 3/4 layers
BTI n
BTI n+1
B (TESLA) radial component
ICATPP 2003
Como october, 2003
BTIs overlap