  The three-dimensional electrostatic field configuration in gas ionization
detectors has been simulated using an efficient and precise nearly exact
boundary element method (NEBEM) solver set up to solve an integral equation of
the first kind. This recently proposed formulation of BEM and the resulting
solver use exact analytic integral of Green function to compute the
electrostatic potential for charge distribution on flat surfaces satisfying
Poisson's equation. As a result, extremely precise results have been obtained
despite the use of relatively coarse discretization leading to successful
validation against analytical results available for two-dimensional MWPCs.
Significant three dimensional effects have been observed in the electrostatic
field configuration and also on the force experienced by the anode wires of
MWPCs. In order to illustrate the applicability of the NEBEM solver for
detector geometries having multiple dielectrics and degenerate surfaces, it has
been validated against available FEM and BEM numerical solutions for similar
geometries.
