Light Yield Measurement of the 1998 Tile Barrel Module0 using muon beams

The light yield for each cell of the Tile barrel Module 0 wasmeasured using 1998 test beam data. Six data sets of muon beams at 90 degreesentering the different tiles centres were analysed.Standard technique of photoelectron statistics evaluation fromsignals of two photo-tubes optically connected to the same cellwas improved by splitting the response spectrum into several slices.The mean values of (41, 49, 53) and (43, 43, 47) photoelectrons per GeV per cell have been measured for the three radial samplings and for the two halves of the Module 0 read-out by different WLS fibres. The differences are discussed in the text.The measured numbers are sufficiently large not to influence the calorimeter resolution. The best value of 53 photoelectrons per GeV per cell is close to the best value of 64 photoelectrons per GeV per cell measured for the 1995 TileCal prototypes.