Time resolution in TileCal Petr Tas Charles University in Prague, Institute of Particle and Nuclear Physics WDS June 8 2005

Introduction Atlas Hadron Calorimeter Module

Introduction Test beam Cell map

Energy reconstruction 25 ns digitizer Gain low - high Flat Filter Fit Method

Time resolution (Todd+Teven)/2 (Todd-Teven)/2 Sigma ~ proportion of precision

Time resolution dT ~ sigma (Cell A-1) Gain cut Select En interval (Tod-Tev )/2 distribution Gaussian fit Sigma ~ dT dT vs En

Flat filter p vs Fit method l

Fit Function sqrt((P1/sqrt(En))2 + (P2/En)2) P1 energy term ~ same for calorimerer P2 noise term ~ low gain x high gain

Fit dT vs En, cell A-1, PMT 2+5, 50 GeV electrons High gain P1=1.91 ± 0.02 P2=0.21 ± 0.33 Low gain P1=2.24 ± 0.24 P2=21.1 ± 1.0

Fit dT vs En 180 GeV electrons, cell A-1 High gain P1=2.06 ± 0.03 P2=0.41 ± 0.19 Low gain P1=2.54 ± 0.04 P2=21.1 ± 0.5

Pions 180 GeV cell A-1 and A-9 l A-1 p A-9

Corrections (Tod-Tev) /2 and (Tod+Tev)/2

Summary Fit method – better resolution Time resolution ~ 0.2 - 0.4 ns