Populating half-circle with triso particles

Hello,

I’m trying to simulate damaged triso cylinders/spheres by populating a half sphere or cylinder with triso particles to simulate one that has broken in half.

I see in the following code example they were able to achieve a similar effect using standard CSG.

https://cardinal.cels.anl.gov/tutorials/gas_compact.html

In their case they have 1/3 of a cylinder, is it be possible to isolate the geometry to include only the 1/3 cylinder and nothing else?