a. meneguzzo padova university & infn

Como 6-10 october, 2003

ICATPP 2003A.T. Meneguzzo Padova University & INFN PadovaA.T. Meneguzzo Padova University & INFN Padova

A. MeneguzzoPadova University & INFN

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.

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.....



Barrel muon system

5 wheels30o sectors with 4 stations250 DT chambers

2.0x2.5 m2 (MB1)4.0x2.5 m2 (MB4)~2*105 channels

480 RPC chambers

MB1

MB2

MB3

MB4

V.Monaco – INFN Torino

8th IACTPP Conference, Como 6-10 October 2003



CMS Drift Tube Chambers

ABCD

tA

tB

tC

tD

“SuperLayer” (SL 2)(coord. in bending plane)

SL (non-bending plane)

honeycomb panel

SL 1

30 c

m

Within one SL 4 layers staggered by half a cell to solve L/R ambiguity

continuous lines represent electrodes dotted lines represent equipotential surfaces

S

g Ws a bb/a ~ .65

13mm

42mm


S

g Ws a bb/a ~ .65

13mm

42mm


S

gC Ws a bb/a ~ .65

13mm



Muon system specifications

Muon identification(after >10 up to 2.4)

Standalone momentum measurement

Charge assignement(up to few TeV)

Trigger on single anddi-muons with variablePt threshold up to 2.1

Bunch crossing assignment

V.Monaco – INFN Torino

8th IACTPP Conference, Como 6-10 October 2003



Laboratori Nazionali di Legnaro (padova): DT chambers construction

glue for I-beam

Final chamberHV & LV boards

LNL



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

•100m precision on wire position within a SL

• <1mm betweenSL

•Resolution of 250mcell

• Max Efficiency •Minimum Noise level

Muon track parameter- muon ID coverage up to IhI=1.1

- momentum & charge assignementNoiseEfficiencyResolution Wire and Layer position accuracy SL position accuracy

we want to measure for each chamber



Chambers and Trigger set up at LNL

Chamber under trigger test

Local Trigger CCB

Chamber under test

Cosmic Rays : trigger set-up



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

MONITOR :on line analysis

–occupancy

-noise

-efficiency

-MT

-Event Display ORCA framework Sara.Vanini et al., PD

Data Base ObjectivityFlat 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



Cell and drift time distribution checks

Strips

Bad cathod

Drift timebad but it can be recovered

good

1800 V

-1200 V

3600V



Noise

Noise of the channels

in all layers of a chamber of all chambers

20 Hz/m

channel

channel

channel



Noise vs Hv and noise vs Th

Noise vs HV on the wire Noise vs FrontEnd Threshold



Efficiency

cell efficiency in the layer efficiency inside the cell

1.00

0.96

wire

I-beamgeometrical inefficiency 1.2/42= 3% for normal tracks



Dead angle= 90

Efficiency :angle & all chambers

Mean SL Efficiency

for the first 12 chambers

98% 99%



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



Mean time fit with ‘time’

-the resolution and the resolution uniformity of the cells along the layer and in the SL

max T t2

t t MT34 2

34 2

t4t3

t2

t1

max

max

T/ V

T t2

t t MT

drift

23 1

123

d

d staggering

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

21000/ 380ns

Vdrift=55m/ns

Resolution=250m

= 1.6ns Wire position accuracy~70msemicolumn

max T t2

t t MT34 2

34 2

t4t3

t2

t1

max

max

T/ V

T t2

t t MT

drift

23 1

123

d

d staggering

Resolution mt=sqrt((2-trig_pm2) =3/2l

2



MT: Layer displacement

t = ( MT234R- MT234L) using the mean value of all MT234 ->good accuracyLayer 4 displacement -> x =t * vdrift

t1

d staggering

t3

t4

t2

t

t1

d staggering

t3

t4

t2

max T t2

t t M M23 1

123R 123L

T T

t1

d staggering

t3

t4

t2

t

t1

Tmax t2

t t MT34 2

234L

d staggering

t3

t4

Tmax t2

t t MT34 2

234R

t2

Mean 378 ns

Mean 383 ns

Example: layer 4 displaced of dx



MT : signal wire propagation

Measurement of the signal propagation along the wire

vsignal=0.244 m/ns

vdrift=21/378=0.55m/nsFEside



MT summary

Drift velocity in the cell

Accuracy on staggering and wire position

sm

Resolution in the cell

For all chambers



MT vs angle

angle angle

The apparent drift velocity grows with angle;it is constant for



Super Layers alignment

x2

x1

All 4 point tracks, | < 20o

build 4 point segmentin each single SL

Extrapolate to themiddle plane of the chamber

62215 m

-3.80.1 mrad

before alignment corrections

MB3_12



Layer alignement : 7 point fit residuals

SL 2

SL 1

MB3_12

<>=655 m

<>=395 m

<>=205 m

<>=-1755 m



2 fit vs SLs displacement

all but one layer included(before layer alignment)

all layers included

2 / NDOF

before layer alignment

after layer alignment

Layer 1excluded

after alignment corrections

8515 m

-0.50.1 mrad



Plateau knee

Hit rate in SL1 is 3.5 (1.7 for SL 2) larger than theworst case at LHC(shown SL1)

CMS Note 2003/007

MB2 :TEST BEAM 2001 Resolution and

Drift cell effic.&resolutionWith increasing Background

192micron

192micron

DT Chamber performance in Test Beam



DT Chambers: 1st Level Trigger

****

****

***

****

**

***

*H

H

L

H

HL (LH)

H

N

Ho

*

*

***

*H

N

Hi

BTI outer

BTI inner

HHTRACOTSS/TSM

*

*

*

SL2 BTI outer

SL1 BTI innerH 4 points trackL 3 points track



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)

Bunch crossing identification

output triggers with 3(L) or 4(H) hits trigger tracks in each SL ->correlated trigger

Angle trigger

Angle track-450 450



Bunched TB 2003 DTchamberTriggerPreliminary

~ 98-99 % efficiency up to 350

tracks hitting 2 I-beams

trig. at 14bxefficiency = total # of events

Event= scintillator + 2 hits in beam region

“EMULATOR” is a SW package that emulates the full chain of the TriggerChips and Boards. It works offline and need as input the times recordedby the TDCs. “Emulator “ is not the CMS simulation,it should reproduce exactlythe 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.




















trig. atefficiency = total # of events



Preliminary DT Trigger Performance - Sara Vanini SIF 2003



CONCLUSIONs

Noise <25 Hz/mEfficiency uniform 99% / layer cell layer vs phi angle vs theta angleResolution ~ ~ 250250/cell 100/cell 100/SL/SL

Mean Time: cell layer phi angle theta angle Layer position accuracy < 110 all Layers/SLall Layers/SLSLs position accuracy < 1mm linear fit Trigger tests with cosmic good

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:

Cosmic rays are free, have no schedule , illuminate uniformly, are in all production sites.



The Installation Task

1

42

3567

89 10 11

12

The Barrel Muon system comprises 250 chambers in 7 flavors:

60 MB1 3SL 2 RPC ~2.0 x 2.54 m2 960kg60 MB2 3SL 2 RPC ~2.5 x 2.54 m2 1200kg60 MB3 3SL 1 RPC ~3.0 x 2.54 m2 1300kg

40 MB4 2SL 1 RPC ~4.2 x 2.54 m2 1800kg

10 MB1 2SL 1 RPC 10 MB2 2SL 1 RPC10 MB3 2SL 1 RPC

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).

SL

SL

SLHoneycombMB4 (Torino)

Have two Superlayers only

help1



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 positionof 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

42 mm


SgC W

s a b

b/a ~ .65

13mm

LHCC Comprehensive Review 10/2/01 CMS MUONS: Drift Tubes and Alignment fabrizio

Help cell



LNL 5/9/2003 96 SL 32 CHAachen 15/8 102 SL 34 Madrid 10/9 120 SL 34 CH

100 ch out of 210

Chambers at ISR MB1 20 by dec.03 29 MB2 28 38 MB3 25 30

Total 73 97

These figures can imply that all the dressing will be done for all chambers at ISR (to be agreed)

Help schedule



*

*

*

*

*

*

*

*

aa

bShift registers

a +b = T

Help BTI



Help ISR

BX Efficiency -2

HH HL LL

Ho Hi Lo Li

drop of correlated efficiency at large angles due to geometrical cuts (single BTI 56o traco 42o)

DT Trigger Performance - Sara Vanini 15

Help TB2003 Traco CCB



.31

BTI nBTI n+1

BTIs overlap

B (TESLA) longitudinal component

B (TESLA) radial component

H-trig = 4/4 layersL-trig = 3/4 layers

.05 .1 .16 .21 .26BW

.38 .56 .77 .96 1.15Bn .19

BTI test in Magnetic Field (test beam 2000, CMS note 2001/051)Prob. of one/4 layers affected by delta 16%, more than one 4%

CMS TN 051 2001

Help TB2000 BTI

a. meneguzzo padova university & infn

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