All four driftchambers have the same structure.
Here driftchamber 1 (in sector 1) is decribed.
Fig 1: Geometry tree of Driftchamber 1 in Geant
The keepin volume DR1M (filled with AIR$) contains an entrance
frame, an exit frame D1F2 (both filled with ALUMINUM$) and an
"active" volume D1A0 (STESALITH$) in between.
To account for the different materials the entrance frame contains the volumes
D1I1 (AIR$) and D1B1 (STESALITH$) with
the volume D1G1 (DRIFTGAS$) and the entrance window D1W1
(MYLAR_DET$) inside.
The exit frame contains the volumes D1I2 (AIR$) and D1G2
(DRIFTGAS$) with the cathode foil D1C7 at the beginning and the
exit window D1W2 (MYLAR_DET$).
The "active" volume is distributed into 7 layers D1L0 ... D1L7
(all filled with DRIFTGAS$). Layer 1 to 6 contain the cathode foil
D1Cx (ALU_KATH$) at the beginning and the sensewire foil
D1Sx (ALTUWI_D1$) in the middle.
Fig 2: Cut through Driftchamber at y=0.
The x-axis points upward and the z-axis to the left.
red: frames;
blue: "active" volume D1A0;
yellow: windows;
lightblue: senswire planes;
green: cathode planes;
