QGP France sept 2010Sanjoy Pal Performances of the tracking Chambers of the ALICE MUON Spectrometer 1

QGP France sept 2010Sanjoy Pal ALICE muon Spectrometer x y z muon Spectrometer 2 Physics Goals : Studying heavy quark production via their muonic and semi-muonic decay in Forward rapidity (-4 < y < -2.5) Large quarkonia acceptance down to p T  0 Measurement of Quarkonia production - as a function of centrality (ZDC) - as a function of p T, rapidity St3, St4 and St5 Slats type St1 and St2 St1 and St2 Quadrants type Muon Tracking System: Five stations Two detection planes for each station. Detection plane consists of Multi wire proportional chambers with bi-cathode pad readout: bending and non-bending. Expected Spatial resolution below 100  m in the bending plane, around 700 µm in the non-bending

QGP France sept 2010Sanjoy Pal 3 Muon Tracking System Muon Tracking System: The total area of covers about 100 m 2 Total number of readout pads about 1 million Gas Mixure : Ar + CO2 (20%) High Voltage : 1650 Volt Wire diameter : 20 µm Wire pitch : 2 mm for St1 : 2.5 mm for St 2,3,4 & 5 Anode cathode gap : 2 mm for St1 : 2.5 mm for St 2,3,4 & 5 Pad width y direction for Bending Cathode 4 mm for St1 5 mm for St 2,3,4 & 5 Pad width x direction for Non-bending Cathode 6 mm for St1 7.5 mm for St 2,3,4 & 5 The chamber thickness : 0.03 X0 Muon Dipole Magnet (Bx) : B=0.7 T, ∫Bdl ~ 3 Tm

QGP France sept Sanjoy Pal Readout buspatches configuration for the NonBending plane in red buspatchs which are present in configuration In white buspatchs which are removed from configuration

QGP France sept Sanjoy Pal Readout buspatches configuration for the Bending plane 5% of the Read out Channel are removed form configuration

QGP France sept Sanjoy Pal Pedestal Bending (max 500 ADC Channel) in black MANU`s which are also dead

QGP France sept Sanjoy Pal Pedestal NonBending (max 500 ADC Channel)

QGP France sept Sanjoy Pal Noise Bending (max 5 ADC Channel) 1 ADC Ch ~ 1000 e Noise below 3 ADC Ch for most of the read out Channel and average around 1.5 Ch which is very good

QGP France sept Sanjoy Pal Noise Non Bending (max 5 ADC Channel) Noise is higher compare to bending plane but it is less critical

Zero-Suppression 10 QGP France sept 2010 Sanjoy Pal The pedestal and noise per readout channel  give threshold for 0-suppression : critical parameter ! Mean and sigma values of pedestals for each readout channel are calculated by DA over 400 event //=========================================================================== // NEW File calculated by makeped //=========================================================================== // * Statistics : 400 // * # of MANUS : // * # of channels : // // //format : // // BUS_PATCH MANU_ADDR CHANNEL MEAN SIGMA // … Flat ASCII file Zero-Suppression is performed by FEE (MARC). Pedestal and noise distribution for one plane of a quadrant

QGP France sept Sanjoy Pal High Voltage configuration 1400 V Nominal HV = 1650 volt 1500 V

Total Cluster charge distributions in pp run 2010 Station 1 have relatively High gain Station 2 have relatively low gain compare to Station 3, 4 & 5 QGP France sept Sanjoy Pal Absolute values of gain are not important for position resolution calculation

No of pad hits in the B plane involved in a cluster for each chamber QGP France sept Sanjoy Pal 3 Pad hit in bending direction is needed for nominal position resolution

QGP France sept Sanjoy Pal No of pad hits in the NB plane involved in a cluster for each chamber

Charge correlation between two cathodes QGP France sept Sanjoy Pal Station 1 Station 2 Station 3Station 4Station 5

QGP France sept 2010Sanjoy Pal 16 Occupancy Bending (max 0.01) Mean Occupancy ~ 0.002

QGP France sept Sanjoy Pal Occupancy NonBending (max 0.01)

Condition to reconstruct a track : one hit among chambers 1 & 2. one hit among chambers 3 & 4. one hit among chambers 5 & 6. three hits among chambers 7, 8, 9 & 10. Total tracking efficiency for LHC10e :  Total = 93.7 ± 0.9 % 18 QGP France sept 2010Sanjoy Pal Chamber Efficiency

QGP France sept 2010Sanjoy Pal Summary We have a quite stable read-out configuration with a busy time most often less than 500 μs ; baseline is 330 μs. We have a quite stable HV configuration. Excellent behavior of all the Muon Chambers was achieved during pp run Tracking efficiency ~95% Ready for HI data taking. 19