Christine KOURKOUMELIS

University of Athens

ATLAS Muon Chamber construction in Greece andalignment studies for H ZZ 4μ decay

Como, 8/10/03

MDT

MDT

TGC

RPC

CSC

Monitored Drift Tubes ( |η| < 2 ) with a single wire resolution of 80 μm 1194 chambers, 5500m2

GREECE constructs 13%Cathode Strip Chambers (2 < |η| < 2.7) at higher particle fluxes 32 chambers, 27 m2

Resistive Plate Chambers (|η| < 1.05)with a good time resolution of 1 ns 1136 chambers, 3650 m2

Thin Gap Chambers (1.05 < |η| < 2.4) at higher particle fluxes 1584 chambers, 2900 m2

Precision chambers

Trigger chambers

ATLAS: Muon Chambers Each detector has 3 stations. Each station consists of 2-4 layers.

ATLAS MUON SPECTROMETER(View of non-trigger chambers)

: MDTsMonitored Drift Tubes

width (tube length) : 83-494 cmlength : 90-216 cm

Tube : Al, 30 mm φ, 0.4 mm wall

Wire : 50 μm, W/Re alloy (97/3)

Gas : Ar/CO2 (93%/7%) at 3 bar

Gas gain : 2x104 at 3080 V

Maximum drift time : ~ 700 ns

Resolution : 80 μm

Anode Wire Mechanical Anode Wire Mechanical TensionTension (350 gf 350 gf 5%5% )

High Voltage Leak CurrentHigh Voltage Leak Current (<2nA/meter)

Gas Leak RateGas Leak Rate (<2*10-2 bar*lit/sec)

Anode Wire PositionAnode Wire Position ( 25 25 μμm)m)

Construction requirements/specifications for MDT tubesConstruction requirements/specifications for MDT tubes

To comply with the above : precision tooling, clean rooms,intense QA/QC tests, etc.. @ all three institutions

University of Athens : Muon tube wiring facilityUniversity of Athens : Muon tube wiring facility

(http://www.phys.uoa.gr/Atlas/MDT)

University of Athens : Muon tube wiring facilityUniversity of Athens : Muon tube wiring facility

Wire insertion –wire tensioning

University of Athens : Muon tube wiring facilityUniversity of Athens : Muon tube wiring facility

Wire threading- wire tensioning

Tube production quality checks

Wiring tension

Finished tube length

DRIFT TUBE PRODUCTION IN THE UoAWORKING CONTINOUSLY SINCE Sept. 2000

STEADY PRODUCTION OF

42 tubes/day

Anode Wire Mechanical TensionAnode Wire Mechanical Tension measurement

.

T = D2 L2 f 2

• L= 165 cm is the wire length• D= 50 μm is the wire diameter ρ = 19.3 gr/cm3 is the density of the wire material

Nominal ValueNominal Value

NTUniversity of Athens : Muon tube testing facilityNTUniversity of Athens : Muon tube testing facility

High Voltage Leak CurrentHigh Voltage Leak Current measurement• A bunch of 16 tubes is connected in parallel and supplied by the gas mixture Ar:CO2 (93:7) at 3 bar absolute pressure and high tension of 3400 V.•The voltage drop across a resistor of 1.1 MΩ in series with the tubes is being measured for each tube.

Leak Current < Leak Current < 2nA/m2nA/m

NTUniversity of Athens : Muon tube testing facilityNTUniversity of Athens : Muon tube testing facility

Gas Leak RateGas Leak Rate measurement

• The idea is to fill the tubes with the detector gas (Ar:93 %, CO2:7 %) and then measure the pressure drop due to gas leakage at the time interval t. • V is the volume of the "leaking" tube and • Δp is the pressure drop.

NTUniversity of Athens : Muon tube testing facilityNTUniversity of Athens : Muon tube testing facility

Anode Wire PositionAnode Wire Position measurement

University of Thessaloniki : Muon chamber assembly facilityUniversity of Thessaloniki : Muon chamber assembly facility

University of Thessaloniki : Muon chamber assembly facilityUniversity of Thessaloniki : Muon chamber assembly facility

Height adjustment of layersRelative position controlled to +-10μm

Rasnik towerresults for 80 chambers

BIS quality tests @ CERN BIS quality tests @ CERN (1(1stst chamber –out of 12 chamber –out of 12

construction sites -to meet construction requirements) construction sites -to meet construction requirements) BIS quality tests @ CERN BIS quality tests @ CERN (1(1stst chamber –out of 12 chamber –out of 12

construction sites -to meet construction requirements) construction sites -to meet construction requirements)

X-RAY TOMOGRAPHYX-RAY TOMOGRAPHY

The results meet The results meet the ATLAS the ATLAS specifications !!!specifications !!!

April-01 April-01 11.7 ÷ 13.9 µm 11.7 ÷ 13.9 µm

July-00July-00 11.0 ÷ 16.2 µm 11.0 ÷ 16.2 µm

BIS tests @ CERN’s-testbeamsBIS tests @ CERN’s-testbeamsBIS tests @ CERN’s-testbeamsBIS tests @ CERN’s-testbeamsX5/GIF X5/GIF 2002 2002

UoA cosmic rays set-up AUTh cosmic rays set-up

BIS tests @ home institutionsBIS tests @ home institutionsBIS tests @ home institutionsBIS tests @ home institutions

G re e c e (1 1 2 B IS )

2 8 -1 0 -0 4

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20

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Jan -00 Jan -01 Jan -02 Jan -03 Jan -04 Jan -05Time

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B are M D TP lan B a re M D TM D T with F CP lan M D T w ith F CF ina l M D TP lan F ina l M D TRead y fo r Ins ta lla tion M S

BIS chamber construction in GreeceBIS chamber construction in GreeceBIS chamber construction in GreeceBIS chamber construction in Greece

Has been going extremely well for 3 years-will finish soon !

Bare chambers production expected to finish by next April

Meanwhile:

•Equip the chambers with services ( gas, electronics..)•Test EVERY chamber with cosmic rays•BE READY FOR INSTALLATION at the pit by Aug.2004 (Olympic games)- 150 chambers

SUMMARY

BIS chamber integration-servicesBIS chamber integration-servicesBIS chamber integration-servicesBIS chamber integration-services

Cosmic ray set-up to test several chambers simultaneously

90 chambers are already constructed, should be equipped and tested

Muon Chamber alignment for Higgs studies

Aim of the study

Estimate how muon chamber misalignments influence Higgs reconstruction into 4 muons, H ZZ 4μ , its mass resolution and the number of accepted events.

Study how can the possible shifts be discovered and estimated from the data.

12

10

8

6

4

2Barrel projective alignment

End-cap pseudo-projective alignment

Global End-Cap translation I. Longitudinal trans. (named displ z)II. Transverse translation (named displ T)

(0, 1, 3 and 5 mm) Global End-Cap rotation I. Rotation around beam axis (named rotat z)

I. Rotation around transverse to the beam axis (named rotat T) (0, 2.5, 5 and 10 mrad)

Only one end-cap was misaligned (the other was kept unchanged- for reference)

The effect of 5 mm longitudinal displacement of one end-cap for the reconstructed Higgs

mH=200 GeV

mH=300 GeV

The relative increase of the width of the reconstructed200 GeV Higgs

Translations

Rotations

The relative decrease in the acceptance of the reconstructed 200 GeV Higgs candidates

Translations

Rotations

Influence of end-cap rotations on Z’s (at least one μ in rotated end-cap)

Effect is big and can easily be spotted!!

The increase of the width of the reconstructedZ’s (when one muon is in the misaligned end-cap)

Translations

Rotations

SM Higgs Potential: 3 YRS @ LOW LUMINOSITY

Conclusions:The misalignments effects we studied :

•can be spotted from their effect on the Z width and corrected for

• will not influence the Higgs potential for the specific channel more than a few percent