A system and methods for transcranial magnetic stimulation, the system including a helmet, a positioning portion, a stimulator and a cooling system, are disclosed. The spindle-top flat surfaces are precisely co-planar with each other. The fluid stream is then introduced into a cyclone that includes a body and a side wall comprising an upper wall portion and adjacent lower wall portion tapering inwardly in a direction away from the upper wall portion. The first rail section has a first rib and a first protruding section; and the second rail section has a second rib and a second protruding section.