An apparatus and method for holding a solid precursor in a sublimator such that the solid precursor can be vaporized for saturating a carrier gas. The apparatus may include alternating disks or shelves that form inner and outer passages, as well as spaces between the disks for fluidicly coupling the passages to create a winding, tortuous fluid flow path through the sublimator for optimizing solid vapor saturation. The method may include directing a carrier gas into a sublimation chamber, around the first shelf in the outer passage, over the first shelf in the space, around the second shelf in the inner passage, and back out of the sublimation chamber.