When the anode wires are at high voltage, electrostatic pressure is exerted
on the cathode planes, which causes the planes to bow in towards the wires
near the center of the chamber unless they are supported by rigid backing
material. This note describes the formalism for
estimating this effect assuming that each cathode can be treated as continuous
conducting membrane and that the number of wires in the chamber is large.
For a given maximum allowed deflection, I estimate the minimum tension that
needs to be applied to the cathode plane before it is attached to its frame.