Back

Answers:
1. The negative part of the $p(r)$ comes from pairs of one scatterer from the core (negative ΔSLD) and one scatterer from the shell (positive ΔSLD).
2. At small distances, the scatterers are of the same type, i.e., they have the same ΔSLD. Therefore, the $p(r)$ is positive at small $r$.
3. The largest distances are between scatterers in the shell, and the $p(r)$ is positive since the scatterers in these pair have the same sign of ΔSLD.