Neon, isotopes, cooling method, cryogenic cycles.
Rectification is an effective method for the Ne-He mixture separating. This method is also used at separation of neon into isotopic components (isotopes 20Ne, 21Ne and 22Ne). It is required to maintain temperatures around 28 K at the pressure of rectification column close to atmospheric pressure. This task has several solutions. Diverse cryogenic cycles, a lot of methods for removing heat and various refrigerants can be used. The simplest method of cooling the column, which is practiced in the Ne-He separation, involves the supplying the refrigerant (98 % Ne) in the top of the rectification unit. For obtaining of stable neon isotopes isolated cooling circuits, in which condensers remove the heat, are used usually. The analysis and experimental study of several refrigeration cycles are carried out. Among them: • throttle cycles on neon and hydrogen at P = 22 and 15 MPa; • helium refrigerator with expander; • cooling circuit based on a two-stage gas cryogenic machine. Neon cycles are the most optimal for this task. They are characterized by economy, high reliability and stability of operation.