The DELPHI Time Projection Chamber (TPC)



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Technical description

The DELPHI Time Projection Chamber (TPC) is composed of plenty of nice things ... ( I will do a more precise description in the next version of this help)

Geometry

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The TPC is a cylinder of 2x1.3 m situated between the radii 0.29 m and 1.22 m .The two drift volumes are separated by a HT (20 kVolts) plate producing an electric field of 150 Volts cm-1. A charged particle crossing the TPC produces by ionisation around 70 electrons per cm of gaz (80% Ar 20% CH4). Under the action of the electric field these primaires electrons drift in the direction of the proportional chambers ( 6 at each TPC extremities).

Sectors

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Clic here for a zoom

Each of 2x6 TPC sectors have 16 raws of pads , alowing the reconstruction of 16 space points per track. In each sectors there is 1680 pads. In front of the pads plates there is 3 levels of grid. the one closest to the pad ( the anode at a HV of 1430 volts ) contains 192 "active" wires (sensitive wires) per sector performing the dE/dx measurement.

Grids

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The 3 levels of grid are composed ( starting from the one closest to the drift volume) :

Electronic

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The 22464 electonic chanels of the TPC ( 2304 for the wires and 20160 for the pads) folow the same idea:

Quantities measured

For each event, 3 types of information are produced :

Accuracy

Social Description

A lot of people are contributing to the running of the DELPHI TPC , we can distinguish between the software field and the hardware field of the activities :

Software

Hardware


P.A
P.J
Y.A