Christine KOURKOUMELIS University of Athens ATLAS Muon Chamber construction in Greece and alignment studies for H  ZZ  4μ decay Como, 8/10/03

MDTMDT MDTMDT TGCTGC RP C CS C Monitored Drift Tubes ( |η| < 2 ) with a single wire resolution of 80 μm 1194 chambers, 5500m 2 GREECE constructs 13% Cathode Strip Chambers (2 < |η| < 2.7) at higher particle fluxes 32 chambers, 27 m 2 Resistive Plate Chambers (|η| < 1.05) with a good time resolution of 1 ns 1136 chambers, 3650 m 2 Thin Gap Chambers (1.05 < |η| < 2.4) at higher particle fluxes 1584 chambers, 2900 m 2 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)

: MDTs Monitored Drift Tubes width (tube length) : cm length : cm Tube : Al, 30 mm φ, 0.4 mm wall Wire : 50 μm, W/Re alloy (97/3) Gas : Ar/CO 2 (93%/7%) at 3 bar Gas gain : 2x10 4 at 3080 V Maximum drift time : ~ 700 ns Resolution : 80 μm

Anode Wire Mechanical Tension350 gf  5% Anode Wire Mechanical Tension (350 gf  5% ) High Voltage Leak Current High Voltage Leak Current (<2nA/meter) Gas Leak Rate Gas Leak Rate (<2*10 -2 bar*lit/sec) Anode Wire Position  25 μm) Anode Wire Position (  25 μm) Construction requirements/specifications for MDT tubes Construction requirements/specifications for MDT tubes To comply with the above : precision tooling, clean rooms, intense QA/QC tests, all three institutions

University of Athens : Muon tube wiring facility (

University of Athens : Muon tube wiring facility

Wire insertion – wire tensioning University of Athens : Muon tube wiring facility Wire threading- wire tensioning

Tube production quality checks Wiring tension Finished tube length

DRIFT TUBE PRODUCTION IN THE UoA WORKING CONTINOUSLY SINCE Sept STEADY PRODUCTION OF 42 tubes/day

Anode Wire Mechanical Tension Anode Wire Mechanical Tension measurement T =   D 2 L 2 f 2 L= 165 cm is the wire length D= 50 μm is the wire diameter ρ = 19.3 gr/cm 3 is the density of the wire material Nominal Value NTUniversity of Athens : Muon tube testing facility

High Voltage Leak Current High Voltage Leak Current measurement A bunch of 16 tubes is connected in parallel and supplied by the gas mixture Ar:CO 2 (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 < 2nA/m NTUniversity of Athens : Muon tube testing facility

Gas Leak Rate Gas Leak Rate measurement The idea is to fill the tubes with the detector gas (Ar:93 %, CO 2 :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 facility

Anode Wire Position Anode Wire Position measurement

University of Thessaloniki : Muon chamber assembly facility

Height adjustment of layers Relative position controlled to +-10μm Rasnik tower results for 80 chambers

BIS quality CERN (1 st chamber –out of 12 construction sites -to meet construction requirements) X-RAY TOMOGRAPHY X-RAY TOMOGRAPHY The results meet the ATLAS specifications !!! April ÷ 13.9 µm July ÷ 16.2 µm

BIS CERN’s-testbeams X5/GIF 2002

UoA cosmic rays set-upAUTh cosmic rays set-up BIS home institutions

BIS 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-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.

Barrel 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 m H =200 GeV m H =300 GeV

The relative increase of the width of the reconstructed 200 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 reconstructed Z’s (when one muon is in the misaligned end-cap) Translations Rotations

SM Higgs Potential: 3 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