The sun is a diffuse emitter. It blankets the entire pyramid in neutrinos. What OP is proposing, I think, is a mobile point emitter and mobile detector. Move t

The sun is a diffuse emitter. It blankets the entire pyramid in neutrinos. What OP is proposing, I think, is a mobile point emitter and mobile detector. Move these around the pyramid and you can create an array of lines that determine the density through the pyramid on that axis. Rotate the entire setup around the pyramid to generate intersecting lines, and you could build up a map. Of course, the pyramid is also moving around the sun, so you do have a distant point source of neutrinos, but not a very consistent or convenient one. And, of course, the detectors are really difficult. Not exactly something you can hang from a quadcopter and fly around the pyramid... :)