Vertical Drift Chambers

The focal plane coordinates are determined in each spectrometer by a package of vertical drift chambers (VDC).

Each package consists of 4 planes, two perpendicular to the dispersive plane, called x-planes, to determine the momentum and the out-of-plane angle of the reconstructed particle. For the other coordinates 2 planes, called s-planes, are tilted by a few degrees.

With this detector we achieve a resolution of

**dx < 100 µm**for the dispersive coordinate**dy < 200 µm**for the nondispersive coordinate**dtheta < 0.3 mrad**for the dispersive angle**dphi < 1 mrad**for the nondispersive angle

The single plane efficiency is better than 99%, leading to an overall efficiency of better than 99.9%.

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Last modified: Thursday, 3. February 2005, 20:19