Abstract: A bubble memory package is comprised of a nonmagnetizable heat sink formed with a pocket for receiving the field coil and magnetic chip carrier assemblies. The heat sink is massive and capable of dissipating the heat generated by a high density memory operating at a high frequency. The heat sink is not closed over the top of the coil and memory carrier assemblies to reduce eddy and circulating electrical currents formed in an electrically conductive heat sink. The heat sink is formed with a track guide for receiving a heat sink plate which may be of electrically nonconductive material but which has sufficient heat conductivity to assist in transferring heat into the heat sink. The top of the heat sink plate is formed with a pocket for receiving a permanent magnet to generate the bias field and the bottom of the heat sink is formed with a second pocket for receiving a magnet assembly. The entire package is surrounded by a magnetic shield container.