Casim Calculations of Soil Irradiation
Ground Water Calculation
Boone Group Meeting - 4/14/98
Since the last group meeting, the decay hall has been shrunk to be
six inches bigger on each side of the detector. With these new
dimensions, I have redone the soil irradiation calculations and
used the concentration model to estimate the ground water contamination.
I get that with the present shielding we will have:
- 1550 pCi/cc tritium (limit = 20 pCi/cc); and
- .16 pCi/cc Na22 (limit .2 pCi/cc).
Again, I believe that the borings will show a much slower
migration rate in the soil and therefore, these numbers are
not now worrisome.
Plots of the radiation patterns are given in the following:
- Hall cross section: This is a linear
lego plot of the cross section of the radiation pattern approximately
at the center of the decay hall. The beam line is at (0,0). The inside of the
hall extends to +/- 168 cm left/right and up/down. Above and below is
90 cm concrete; left and right is 45 cm concrete. The effect of
the thinner left/right walls is apparent from the plot.
- Hall cross section - Logrithmic
A logrithmic contour plot of the soil activation near the center of
the hall. The contours are only
for soil irradiation -- not for any activation of the the hall or wall material.
The contours are close to circular now showing uniform activation
in all directions.
- Left/Right distribution of activation.
Plotted is the total number of stars in the soil for 5x10^5 POT in the
region between +/- 5.5 ft in y. Our largest concentration is still at
the end of the hall where particles are slipping by the unshielded endges
of the dump.
- End of the Hall: The activation of the
dirt at the end of the hall. With the smaller leakage area around the edges
of the detector, the activation is much more uniform than before. There
is a slight excess at the edges but not anything appreciable.
is clear.