question about the mesh

in comsol i have made a 3D model:
There are two Geometries, a big sphere and a small cylinder in the sphere.
the mesh of the sphere can be made coarser, it's not important.
for the mesh of the cylinder, i want to make the edge of the bottoms of the cylinder feiner but in centre coarser.

i have tried to use the "boundary layer" to make the mesh for the cylinder. And then used the “Free Tetrahedral” to mesh the rest. but it doesn't work. only "Free Tetrahedral" is working and “boundary layer” hat no effect.

so how can i reach my goal? thank you for your help!