Design and Experiment of a Helium Liquefaction Cryostat with Vibration Damping Function

Abstract

This paper presents the design and experimental results of a helium liquefaction system with vibration damping capabilities, tailored for synchrotron radiation light source experiments. A 4.2 K GM cryocooler was utilized as the refrigeration source, integrated with a dedicated helium liquefaction system designed to cool and liquefy helium gas. This helium liquefaction device is suitable for scientific laboratory experiments. By analyzing the process of helium liquefaction, a method to improve liquefaction efficiency was proposed. The helium liquefaction rate was increased from 8.2 L/day at 1.1 bar (charging pressure) to a maximum of 15.9 L/day at 1.5 bar. To mitigate vibration effects from the reciprocating piston motion in the GM cryocooler, specialized vibration damping devices were installed to reduce transmitted vibrations to experimental apparatus. By employing welded bellows as vibration isolators, the system’s vibration amplitude was reduced from ± 9.0 μm in the X-axis, ± 9.0 μm in the Y-axis, and ± 21.0 μm in the Z-axis to ± 0.6 μm in the X-axis, ± 0.6 μm in the Y-axis, and ± 1.7 μm in the Z-axis.