Ray-tracing simulations show that some photons miss
the PMT because
of the limited size of the WC opening (see Fig. 7).
This deficiency can be remedied by adding another mirror
to the system.
In order to define the proper shape of this mirror, two
different geometries
were implemented in the CC package code - flat and cylindrical.
It was found that the cylindrical mirror option resulted in
a slightly larger
.
It also proved to be more convenient to fabricate and
to attach to the WC window.
Fig. 8 shows the estimated gain in
from this modification.