A liquid nitrogen immersion cryostat for optical measurements

A liquid nitrogen immersion cryostat has been developed for optical measurements. Liquid nitrogen in the sample chamber is kept free of bubbles and schlieren by the use of a cooling jacket of sacrificial liquid nitrogen, which is kept at a lower pressure than the sample chamber. This design has proven especially useful for volatile liquid samples, where direct electrical connections, rapid sample freezing, and efficient heat dissipation are required, but it can also accommodate a wide variety of other samples. The cryostat is compact, easy to use, and relatively inexpensive. (C) 2000 American Institute of Physics. [S0034-6748(00)01509-4].