1. New MWPC for CB Status Report Oct 2004
Proportional chambers with cathode readout
Wires // beam axis Þ f coord
Segmented Cathodes. Strips helically wound in opposite directions Þ z coord
Wires pitch 2 mm
Gas gap 8 mm
Resolution: s(f) » 2o , s(q) » 1o
Work by A.Braghieri

2. First Idea
Cathode made by a double sided FR4 PCB: Fiber glass 100 mm and Cu 17 mm
Large surface of the PCB 1200 x 500 mm2
Folding technique

3. PCB Layout

4. … Folding technique Problems Cost: 2 KEur/cathode
Folding: very difficult to ensure necessary precision (roundness). Cusp at the border

5. A more traditional technique
Cathode support: Rohacell
Strips: on a Kapton foil glued on Rohacell
Advantages
Cheaper
More transparent
Easy to machine
but …
Electrical connection problems (can be solved)

6. Preliminary Project for two MWPCs
Ch 2
Ch 1
Inner dia 129 mm
Outer dia 205 mm
Diameter of the new polarized target » 120 mm

7. All signals from the upstream part: only 2 chambers can fit inside the available space
The 2 new chambers will be closer than the existing ones ) angular resolution will be ' 1.5 worse than now (sq ' 2-3 degr.)