Accumulation

The xenon is mixed with nitrogen and helium before it is heated and passed over liquid rubidium. The heated rubidium contributes a very low density rubidium vapor to the mixture which is needed for magnetizing the xenon. After the xenon is magnetized, the mixture passes out of the heated region through a glass tube at room temperature. The rubidium separates from the gas mixture and sticks to the walls. Then the mixture flows through a heat exchanger immersed in liquid nitrogen. There the magnetized xenon freezes and sticks to the walls. All this takes place in a magnetic field.

We developed an apparatus that freezes and thaws the xenon automatically and without losing any of its magnetization. As the xenon gas mixture is flowing downward through the heat exchanger, we slowly raise the liquid nitrogen bath. This procedure results in a thin, even distribution of the xenon frozen to the surface of the glassware. The thin layer maintains its magnetization through freezing and thawing better than a thick chunk. Previous techniques would lose as much as half of the xenon’s magnetization by freezing and thawing.