A junior researcher at the Laboratory of Nuclear Reactions at JINR Vladimir Trofimov is the author of a patent for a utility model of a discrete heat exchanger for refrigerator for dissolving He³ in He⁴. The utility model relates to heat exchange devices and can be used in cryogenics to obtain low temperatures, including in He³ in He⁴ dilution refrigerators, which allow obtaining an ultra-low (up to 2 mW) stationary temperature.

The discrete heat exchanger of the He³ in He⁴ dissolution refrigerator contains a flat disc-shaped body with two hermetically sealed cavities formed inside it. The cavities include a sintered fine structure, a bottom, and a lid with two through holes, into which pipes are installed for the entry and exit of a dilute and concentrated He³ in He⁴ solution. The bottom of the case is made integral. Two hermetically separated cavities are made in the form of two annular channels coaxially located on the bottom of the housing from its inner side, lying in the same plane. The pipes for each He³ phase are located on the same diameter: one pipe for each He³ phase is on top of the heat exchanger, and the other is on the bottom. The diameters of the nozzles of concentrated and dilute solutions of He³ and He⁴ are rotated 90 degrees relative to each other. The sintered fine structure can be made of multilayer sintered braided wire tape. Through axial holes of equal diameter can be made in the body, bottom, and lid. The technical result is a reduction in the temperature difference between the incoming streams of liquid helium and the decrease in the volume of He³ filling the heat exchanger block.

The patent holder is the All-Russian Scientific Research Institute of Experimental Physics of Rosatom on behalf of the Russian Federation. The RU 232147 patent for the utility model “Discrete heat exchanger for refrigerator for dissolving He³ in He⁴” was obtained on 26 February 2025.

Congratulations to Vladimir Trofimov on receiving the state registration!