The thermal column is a graphite-filled horizontal penetration through the biological shield which provides neutrons in the thermal energy range (about 0.025 eV) for irradiation experiments. The column, which is about 8 feet long, is filled with about 6 feet of graphite. A small experimental air chamber (40″ x 40″ x 24″) between the face of the graphite and the thermal column door has conduits for service connections (air, water, electricity) to the biological shield face.
Personnel in the building are protected against gamma radiation from the column by a dense concrete door which closes the column at the biological shield. The door moves on tracks set into the concrete floor perpendicular to the shield face.