External beam chambers PC1x/y

Between the muon scintillators and the TPC entrance window, two small external wire chambers, $\mu$ PC1x and $\mu$ PC1y will be mounted. The chambers will accurately define in the x-y plane the entrance geometry to the pressure vessel. The chamber parameters are given in table 2. The anode frames will be constructed in Gatchina.

Table 2: parameters of muon wire chambers and TPC

	$\mu$ PC1	$\mu$ PC2	TPC
size (mm $^{2}$ )	50x50	110x110	150x300
anode-cathode gap(mm)	4	3.5	3.5
anode wire spacing(mm)	2	4	4
anode wires diameter( $\mu$ m)	25	25	25
anode frame material	PCB	SiO $_{2}$	SiO $_{2}$
cathode wire spacing(mm)	1	1	1
cathode wires diameter( $\mu$ m)	50	100	100
cathode frame material	stainless	SiO $_{2}$	SiO $_{2}$
wire material	W(Au)	W(Au)	W(Au)
strip cathode wire spacing(mm)	-	-	1
strip cathode width(mm)	-	-	4
anode readout wires	2x25	2x27	74
strip cathode readout wires	-	-	37