  We study the creation of a spherical, finite radius source for a quantized
massless scalar field in 3+1 dimensions. The goal is to model the breakdown of
correlations that has been proposed to occur at the horizon of an evaporating
black hole. We do this by introducing at fixed radius $r=a$ a one parameter
family of self-adjoint extensions of the three dimensional Laplacian operator
that interpolate between the condition that the values and the derivatives on
the two sides of $r=a$ coincide for $t\le0$ (no wall) and the two-sided
Dirichlet boundary condition for $t \ge 1/\lambda$ (fully-developed wall).
Creation of the shell produces null, spherical pulses of energy on either side
of the shell, one ingoing and the other outgoing. The renormalized energy
density $\langle T_{00}\rangle$ diverges to positive infinity in the outgoing
energy pulse, just outside the light cone of the fully-formed wall at
$t=1/\lambda$. Unlike in the 3+1 point source creation, there is no persistent
memory cloud of energy. As in the creation of a 1+1 dimensional wall, the
response of an Unruh-DeWitt detector in the post-shell region is independent of
the time scale for shell formation and is finite. The latter property casts
doubt on the efficacy of this mechanism for firewall creation.
