Status of MUON calibration

Alignment tracker (see Ivana's talk)

Calibration tracker

Calibration & alignment trigger

Realistic mapping

Conclusion & ToDo

Absorber

5 Tracking Stations

2 Trigger Stations (RPC)

Filter (Iron Wall)

Dipole

DIMUON Arm :

Pseudo-rapidity range : -4.0 < h <-2.5

MUON Spectrometer

Tracking Stations

4*4 Detection Elts

2*18 + 4*26 Detection Elts

Alignment and Performances

Figures from E. Dumonteil thesis

Mass (GeV/c2)

Mass (GeV/c2)

Mass (GeV/c2)

Mass (GeV/c2)

(105 MeV)

’(120MeV)

’’

Chamber position exactly known

100 μm uncertainty on chamber position

500 μm uncertainty on chamber position

1 mm uncertainty on chamber position

(135 MeV)

’(190MeV)

’(220MeV)

(170 MeV)

(220 MeV)

Alignment scenario

Alignment (~30 microns precision):

1 TTransformation per tracking detection element: 156 detection elements (23KB)

At most, an alignment per day.

Physics alignment algorithm need around 60000 tracks without magnetic field (~ 1-5 minutes of beam).

GMS need 5 minutes after switching on the magnet.

One physics (straight tracks) and GMS alignment per beam fill should be possible.

Algorithm in AliRoot (Bruce BECKER from Saclay) convert STL to Root

Alignment

Geometry:

The position of the « envelops » could be stored in a ASCII file.

Config file: MUON->SetAlign(kTRUE) (see Ivana's talk).

Link with database could be done easely.

Calibrations for tracking system

Gains :

Initial FEE calibration in Industry (FEE serial number + 4 parameters)

 ~10 MB for database.

Calibration during the experiment: address (int) & 3 calibration coefficients (float)

 ~40 MB for database.

We could expect, at most, two calibrations per day (40MB x 2 x 300 = ~25 GB per PbPb + pp run). This is raw estimation and an upper limit!

Mapping between FEE serial number and FEE address ~9 MB

Pedestals:

Address (int) & Mean (float) & Sigma (float) for all channels

 ~40 MB for database.

Should be handled by DAQ-ECS (need 'link' between on- and off- line database).

In principle one pedestal run per beam filling period (~8 hours).

Dead Map:

1 Dead map per filling period (~8 hours)

1.1 million channels, if everything is dead a 8.8MB

Calibration for trigger system

Calibration & pedestals:

No calibration & pedestals needed (no charge measurement).

Alignment (1mm precision):

A unique alignement before the data taken.

1 Ttransformation per trigger detection element. 72 detection elements

 10 KB.

Dead Map:

1 Dead map per filling period (~8 hours)

21000 channels, if everything is dead a 160KB

Realistic Mapping (i)

Motif method :

Defines base motifs that could be use to 'assemble'

Gives the padX, padY, posX, posY and the electronics id and channels.

Motif method :

Defines base motifs that could be use to 'assemble' sectors (St1 & 2) and slats (St345).

Gives the padX, padY, posX, posY and the electronics id and channels.

Realistic Mapping (ii)

Slat assembly :

Those motifs describe the PCBs which compose the slat.

The 1.1 millions channels has been mapped.

The generation of rawdata is working as well

as the reconstruction (including ESD) from rawdata.

Conlusion & ToDo

We have defined our needs for the calibration & pedestal database.

The framework with the real mapping is working.

Since we do not know whether our electronic needs or not calibration, the forseen test with database will be with pedestals (not substracted online).

Generates pedestal

Store into database

Retrieve the pedestal

Subtract pedestal

 should be done in next weeks.

2005-05-30T22:50:11