CAL RECON 01/26/05

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still working on direction and energy reconstruction above 5 GeV

cal only events direction reconstruction:
- use the barycenter in each layer;
- modify the z position of each layer depending on the energy deposition along the layers;
- chi2 fit using minuit : minimizing the distance of the intersection of the trajectory in each layer to the barycenter;

there is a negative bias increasing with the incoming angle.
this is cured by further modifying the z position of each layers.

PRELIMINARY RESULTS FOR THE PSF 68%:

I am now working on trying to improve the PSF by taking into account the pixelisation effect and the passage through cracks.
Unfortunately none of my ideas have succeeded so far...

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energy reconstruction :
- using the reconstructed trajectory to determine the history of the trajectory in radiation length units;

triangles : my version of the average profile fit;
circles : my profile fit;
PRELIMINARY RESULTS FOR THE ENERGY RESOLUTION:

I am now looking at what is happening at "low" energy with my profile fit.
it seems that by restricting the position of the maximum of the shower to be less than the length of the trajectory in X0 units + 1, one gets resolution equal to 10%.