Cryogenic temperature gradient microscopy chamber

A controlled low temperature chamber for a microscope comprising:

• a housing forming a vacuum chamber and having a top panel and a bottom panel;
• mounting means in said chamber for mounting a sample therein for microscopic observation, said mounting means including a base member, a pair of spaced supports extending substantially perpendicularly from the base member and a pair of spaced platforms supported by said supports, each of the platforms having an upper surface to support said sample and a spaced undersurface beneath said upper surface;
• and
• a temperature control system for maintaining a cryogenic temperature in the chamber, for applying a controlled temperature gradient on said sample and for moving, and controlling movement of, the temperature gradient along said sample to directionally solidify and melt said sample, said temperature control system including
• i) independent electric heating means on said undersurfaces of said platforms,
• ii) thermal sensors positioned along said sample,
• iii) computer means controlling the energization of said electric heating means, thereby permitting independent stabilization of each end of the sample to any selected temperature, whereby a selected temperature gradient is imposed across said sample and said electric heating means modified the gradient and moves the gradient along said sample, and
• iv) temperature control means for circulating a temperature control fluid in said mounting means,
• whereby the combination of the temperature control fluid and electric heating means permits melting and solidification reactions in the sample to be observed via said top panel of said chamber housing via one of light transmitted through said bottom surface of said chamber housing, and light reflected through the top surface of said chamber housing said temperature control means circulating the temperature control fluid through the base member of said mounting means.