The measurements of magnetic elde ects on scintillating tilesJ

We display the eeects of the magnetic eld on the light yield of the tiles used in the Atlas Hadronic Calorimeter. Covering a large range, from the Earth eld to about 1 Tesla, these results are in agreement with other experiments showing that the light yield of polystyrene based scintillator is increased by about 1% below about 100 mT, with a jump of about 0.6% at 1.2 mT and a 1% plateau starting at about 1.5 mT. This eeect does not depend upon the eld direction. Considering that in Atlas the magnetic eld does not exceed 6 2 mT in the tiles (located in the worst Tilecal place), the conclusion is there will not be a sizeable eeect on the absolute energy calibration and the cell-to-cell intercalibration.