We have simulated
the effective radiation damage to the CUBIC CCDs on a yearly
basis for a variety of proposed SAC-B orbital parameters.
Our original simulations were for
a Skipper CCD (1024 X 1024 pixels, 1.5 e
rms readnoise)
similar to the Lincoln Lab (LL) CCD (420 X 420 pixels, 3 e
rms readnoise). An initial estimate of 3mm Al shielding was assumed,
with an unshielded 
field of view. Trapped proton
fluxes for each orbit were assumed to be isotropic. CCD damage
was calculated using the radiation transfer model and radiation
transfer efficiencies developed by Janesick (1990), and a proton
transfer curve calculated for the specific CCD architecture using the
TRIM-90 Monte Carlo particle interaction program.
The results of these
simulations showed that high altitude and high inclination orbits proposed
for SAC-B would produce unacceptable detector degradation for CUBIC \
and resulted in the choice of a 
inclination, 600 km altitude orbit
for SAC-B .
(This was later changed to a 550 km orbit to accommodate HETE).
This model of detector damage was further refined with the addition of detailed calculations of the particle transfer through the CUBIC shielding. Detailed results are presented in Antunes et al. (1993). The basic conclusion from these detailed simulations is that CTE is likely to be noticeably degraded by the end of the first year of operations.