1. I need to be efficient
•
It is inherently beneficial to work in spherical
coordinates to lift the kernel singularity since:
dV=dS dr=r
2
dΩ dr = r
2
sinθ dθ dφ dr
j
V
dVjh i 1sc,
S
jρ
iρ
1scD
j i
r
sin2r
2r
)
exp(
i 1sc,
S
jρ
iρ
dr dd
rb
B
•
Instead of evaluating ALL directions around a
scerma generating point, I can DISCRETIZE space
using a number M of solid angle elements, ΔΩ
M
,
i
defined by (θ
0
,φ
0
)
M
, and assume
scerma does not
vary with θ within ΔΩ (i.e. on dS for a given r)
dd b
B
)
e p(
Siρ
D
r b
B
r
r
r
j i
dr ) 0
exp(
0
1sc,i
S iρ
x
1sc,i
jρ
1sc
r
jρ




