  The Cryogenic Dark Matter Search (CDMS) utilizes large mass, 3" diameter x 1"
thick target masses as particle detectors. The target is instrumented with both
phonon and ionization sensors, the later providing a $\sim$1 V cm$^{-1}$
electric field in the detector bulk. Cumulative radiation exposure which
creates $\sim 200\times 10^6$ electron-hole pairs is sufficient to produce a
comparable reverse field in the detector thereby degrading the ionization
channel performance. To study this, the existing CDMS detector Monte Carlo has
been modified to allow for an event by event evolution of the bulk electric
field, in three spatial dimensions. Our most resent results and interpretation
are discussed.
