Patent ID: 8777831

Claim:
A transcranial magnetic stimulation induction coil device comprising: at least one coil winding having inner and outer surfaces at first and second radial lengths, respectively, from a center of the coil winding, wherein the first surface defines an aperture; and a casing including a bottom wall and a side wall defining a receiving region, wherein the receiving region contains the at least one coil winding and the at least one coil winding includes a bottom surface facing the bottom wall, wherein the bottom surface of the at least one coil winding and an inner surface of the bottom wall define a space and the space contains a gas, and a ring having an outer surface at a radial length from a center of the ring substantially equal to the first radial length, wherein the ring is positioned within the aperture of the at least one coil winding such that the outer surface of the ring is in contact with the inner surface of the at least one coil winding.