1. dE/dx in ATLAS TILECAL Els Koffeman Atlas/Nikhef Sources: PDG DRDC (1995) report RD34 collaboration CERN-PPE-96-173

2. ATLAS -Tilecal Hadron – interaction produces shower with new hadrons and neutrons, neutrinos and EM part Muon – Deposits energy through ionisation Jets 1 tower 4 cells 3 segments

3. Sampling with scintillator Measure visible photons created by charged particles Number of charged particles in the shower give estimate for total visible tracklength EM shower is used for primary calibration Absorber Detector The Tilecal consists of 78% iron, 17 % polystyrene and 5% of air. The sampling fraction is 3.4 %

4. Signal calibration PM converts a single photon to many electrons Finally convert charge to energyloss of incident particle Calibration with electrons (no missing energy) – 64 photoelectrons/ GeV and – 5.6 pC /GeV E / E c 1 Gev / 20 MeV gives 50 MIP’s MIP creates 200 visible photons PM efficiency 20%, gain 10 6 4x10 7 electrons Photomultiplier (PM) Wavelengthshifter (WLS) Scintillator

5. Muons Below 100 GeV the fluctuations in energy loss contribute to the momentum resolution Soft muons important in B-tagging

6. Energy loss of muons

7. e/h and e/mip ratio Is the output for 50 GeV electron the same as for a 50 GeV pion? Is this important ? What about 50 GeV muon do ? – E loss of ‘MIP’ = 1.5 GeV – Muon loses 2.3 GeV (of which 80 MeV in tiles)

8. Precision Reconstruction Below 10 GeV calorimeter is dominates the momentum determination Resolution is limited by the primary p.e. statistics High energy muons also ‘suffer’ from bremsstrahlung Use this to correct the energyloss ! (is it used ?)