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The image MuonWithCUshows the distribution of energy deposited in the calorimeter when a muon goes through it. This is a typical image; not a rare event. Note that the track is "brocken"; every other layer there is a "hole" in the track, the energy deposited in that layer seems to show up off the track. The FRED Images 1,2,3 and 4 show the first 4 consecutive events from that run (after the application of the selection criteria described above). You can see the same behaviour in all them. The FRED image Evt4 Evt0_4Views shows the event 4 0 from 4 different perspectives. Note that
the Z-X perspective is different from the Z-Y perspective. In the first one the layers 1,3,.5,7 are alined and the layers 2,4,6,8 are off; whereas in the other the opposite occurs.
Anders and Leon atributed this effect to a wrong crystal diode relative calibration; since the position of the event along the crystal is determined comparing the signal produced in each of the diodes at the end of the crystal. This wrong relative-calibration seems to occur in all the layers.
This effect deteriorates the reconstruction of the direction of the event in the calorimeter; which is clearly observed in the clear track is visualized, and consequently the direction of the muon event can be (up to some precision) reconstructed for a large fraction of the events using only information from the calorimeter. The distributions of the variables Trk1ZDir and CalZDir are shown in MuonSLACReconstructionMuonPisaReconstruction.gif, MuonSLACReconstructionMuonPisaReconstruction.ps and MuonSLACReconstructionMuonPisaReconstruction.root(gif, ps and root files). Note that (for this data and selection applied) the muon direction in the calorimeter (CalZDir) is properly reconstructed for most ONLY a TINY FRACTION (3%) of the events, as expected.
Electrons @ 5 GeV
David please include run numbers
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