Parallel Plate Chamber Design (Govinda Rajan)

PP chamber design is very simple.

1) Take two circular perspex plates of about 1 mm thickness and about 4or 5 cm in diameter.

2)Coat the inside of one disk with graphite(aquadaq).

3) Take the other disk and keep a thin ring of less than or equal to one mm thickness and 1 cm in diameter and keep it concentric with the disk centre and now coat with graphite. You now have the central collecting electrode and the outer guard with a smallinsulating gap in between.

4) Take a perspex ring of anout 5 cm diameterand about 2 mm thickness and fix the two disks on the ring with the graphite coated portion on the inside. you now have the high tension electrode, the central electrode and guard.

5)Now you have to take the connections. HT wall is the entry window. If you want dose at smaller depths you must make this wall thinner. If you want the cavity thickness to be smaller than 2 mm you must use a ring of smaller thickness as spacer between the two electrodes. If you want a larger electrode you must use a larger inner ring before coating withgraphite.If you need a larger guard, the diameter of the perspex disk chosen must be larger.

If you see the protocol. you will find PP chambers of different sizes because of changes in the parameters thatwe discussed. How the characteristics will depend on these dimensions are given in the protocol.If you can make the spacer ring whose thickess can be varied, you have an extrapolation chamber. If you make the wall materials interchangeable you can study wall effects.

You need some expertise to attach wires to the central electrode,guard and HT wall and take out and connect to cable.Hope this gives you some idea of PP chamber

Govinda Rajan.K.N.Govinda Rajan.K.N.