PRODUCTION OF THIN SOLID-HYDROGEN FOILS FOR USE AS TARGETS IN HIGH VACUUM

Thin solid-hydrogen disks with a lifetime of about 10 min were produced by freezing a liquid-hydrogen film spread over a hole in a liquid-helium-cooled condensation plate. The transparent self-supporting disks have a diameter of 2 mm, and they diminish in thickness from initially about 1 mm to zero as a result of slow vaporization. The method described here enables materials which are gaseous under normal conditions to be produced as solid foils in high vacuum. This can be done in quick succession by means of the simple apparatus described. Such foils can be used, for example, as targets for producing plasma by laser light.