You will find the parameters for the originally used chambers on the MWPC web page: Multiwire Proportional Chambers.
The parameters which have changed are the helix angles of the cathode surfaces, which are now:
alpha_inner = 43.956 degrees
alpha_outer = 41.703 degrees
The actual diameter are:
d_cath_inner = 114.65 mm
d_anode_wires = 120.14 mm
d_cath_outer = 125.65 mm
The number of cathode strips is the same. The strip spacing is 4 mm. The gap between two strips is 0.3 mm now.
Sketch of the inner and outer surface:
The plateau curve (efficiency vs. chamber high voltage) was measured on 19th-Nov-1999 by A. Korenchenko:
The operation voltage is at the beginning of the plateau at 2250 V.
H.P. Wirtz , 22-Nov-1999
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Plateau curve
This picture is also available as PS-file.
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last update: 24-Nov-1999
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