which is about the surface area of a sphere at 4.4m radius
Does the onion really need to be a sphere? Creating a multi-layer sphere seems like a fairly daunting engineering task compared to creating flat panels. Is it necessary for the x-rays to hit the surface at a normal angle? If not, I would think that simply six panels, put together as a cube, would be a much simpler design — the panels themselves could be mass-produced far more easily. Presumably one wouldn’t even need to join the panels, as long as there was no space for the x-rays to leak through externally — just ensure that the panels overlap sufficiently that there are no through gaps.
