Status of Atlas Tile Calorimeter and Study of Muon Interactions L. Price for TileCal community Short Overview of the TileCal Project mechanics instrumentation electronics TileCal and muons muons for calibration of the TileCal measurement of muon energy losses
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Status of Atlas Tile Calorimeter and Study of Muon Interactions L. Price for TileCal community
Status of Atlas Tile Calorimeter and Study of Muon Interactions L. Price for TileCal community Short Overview of the TileCal Project mechanics instrumentation electronics TileCal and muons muons for calibration of the TileCal measurement of muon energy losses. - PowerPoint PPT Presentation
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Status of Atlas Tile Calorimeter and Study of Muon
InteractionsL. Price for TileCal community
Short Overview of the TileCal Projectmechanicsinstrumentationelectronics
TileCal and muonsmuons for calibration of the TileCalmeasurement of muon energy losses
ATLAS hadron calorimeter TileCalTileCal community = 24 institutions
TileCal within the Atlas detector:- measures jets energies and directions- provides ATLAS with LVL1 trigger signals
TileCal - Barrel and 2 Extended barrels, each cylinder consists of 64 modules
Principle of TileCal is a measurement of scintillation light produced by charged particles in plastic scintillator.
TileCal modules production:
BARREL - 65% of modules finished in JINR Dubna
EB A - 50% modules finished in US EB C - 73% modules finished in Spain
564 cm
292 cm
Modularity of the Tile Calorimeter
3 cylinders - barrel and two extended barrels
Each cylinder consists of 64 modules (+1 spare)
SUBMODULES Total number of submodules needed:65x19 + 2x65x9 = 1235+1170 = 240590% is done and the production of submodules will finish in the spring of 2002.
1. Stacking
2. Welding
3. Painting
Barrel = 19 submodules,Extended barrel = 9 submodules + special ITC submodules - more than 50% are finished
Monitor of production quality in all 9 plants
Scintillator tiles (100% are produced)wrapped in Tyvek sleeves
profiles with inserted fibres (65%)
Instrumentation of modulesin 4 different plants
Instrumentation of modules:
In total more than 50%modules are ready for calibration and preassembly
Cell to cell uniformity 6-7% < 10% (target value)
Cells are formed by making fibres bundles
Cylinder preassembly will start in April 2002 in building 185 at CERN
- EB C will be assembled first- Barrel- EB A
Installation in the pit is foreseen to start in Dec 2003 with the barrel
180 cm
564 cm
Electronics
Main goal is to start serial production of drawers containing electronics
PMT‘s : 45% of tubes delivered and good quality proved by tests in 6 different labs.
PMT test bench
8 barrel modules and 16 extended barrel modules will be calibrated using particles.
Calibration of modules will be done with Cs radioactive source for all modules
90° Incidence
20° Incidence
H8 Table Setup
2001 Tiles Testbeam Program
Response to 180 GeV muons, pions, electrons
180 GeV e at 90°
Summary
180 GeV e at 90°
Summary
Target Value
1.2 pC/GeV/Cell
Target Value
1.2 pC/GeV/Cell
Interactions of different particles inside the TileCal
electron
pion
muon 1/50
1/500
Calibration of the TileCal using muons
•Cells of the first longitudinal sampling are calibrated with electrons of 20 to 300 GeV
•All calorimeter cells are calibrated relatively each to other using Cs radioactive source. •Precise description of TileCal response to muons (ATL-TILECAL-97-114). The most probable value of the muon signal can be used for the calibration.
Muon signal can be used also for in situ calibration.
Calorimeter light yield measured with muons
L
R
L + R
σ (L - R)2
muon
slope ~ 1/ Npe
Signal in each TileCal cell is read out from two sides L and R. Differences of signals are caused by photoelectron statistics
Typical values are 50-60 photoelectrons per 1 GeV of energy deposited in cell.
Muon energy losses in iron
Muon s with 150, 180 GeVare close to the critical energy
Physics motivation for muon energy loss measurements
•Muon traverses more than 100 radiation lengths of dense calorimeter material before being measured by the muon system.
•There is a probability of 60 % that in H-> 4 μ at least one muon loses more than 10% of its energy (P~.002/rl)
•It is therefore essential to measure muon energy losses in the calorimeter
•Also the highest muon energy losses are dominated by bremsstrahlung and momentum transfer to nucleus is much higher than for electron bremsstrahlung. Consequently nuclear form factor should be taken into account.
•Nuclear form factor corrections were not known experimentally and different theoretical predictions exist.
•Photonuclear interactions of high energy muons at low momentum transfers are also poorly known experimentally and theoretical predictions implemented in different MC codes vary by an order of magnitude.
Measured differential probability of muon energy losses in TileCal prototypes
Published in Z. Phys. C 73 (1997) 455.
Theory without and with the nuclear formfactor correction to bremsstrahlung
Detailed measurements with the TileCal Module 0
μ
Nuclear form factor correction to muon bremsstrahlungEur. Phys. J. C 20 (2001) 3, 487-495
Atomic radius a times the minimal momentum transfer to nucleus δ
Unscreened nucleusScreened nucleus
(Published calculations give 0.5 to 1.5)
Measurement of muon photonuclear interactions
Top modules
Coordinate z
Coordinate z
Photonuclear int. Background
Central module
Bottom modules
muon
Photonuclear interactions: μ+A —>μ+ hadrons
Differential cross section of muon photonuclear interactions
(preliminary results)
Theory[C.19] Bezrukov, Bugaev,Sov. J. Nucl. Phys. 33 (1981) 635.
H1, ZEUS
Normalization is proportional to σ(γN)
σ(γN)
E lab
Our measurement
Summary
•Production of instrumented TileCal modules has passed 50% point and is progressing well.
•Production of superdrawers with electronics has started, first production modules have been calibrated at the beam and serial production will continue in the autumn after beam tests.
•Detailed studies of muon signal have been done with the TileCal module 0. Different mechanisms of muon energy losses has been studied, nuclear form factor correction to muon bremsstrahlung has been measured.
•Preliminary results about muon photonuclear interactions in iron have been presented.