Development of Gas Cell Cryogenic Purification System Operating at Prototype Spectrometer for Neutron-rich Superheavy Nuclei

Multinucleon transfer reactions involving heavy actinide projectile and target nuclei hold significant potential as a groundbreaking method to synthesize neutron-rich superheavy nuclei. Constructing a Prototype Spectrometer for Neutron-rich Superheavy Nuclei is highly desirable to establish the technical, methodological, and device foundation to explore the stability island in superheavy nuclei and to study the mechanism of multinucleon transfer reactions. The gas cell of the Prototype Spectrometer for Neutron-rich Superheavy Nuclei requires a continuous supply of high-purity helium gas to stop the energetic radioactive reaction products and to extract the energy-reduced ions to the subsequent experimental setup. The paper focuses on a newly developed Gas Cell Cryogenic Purification System operating at Prototype Spectrometer for Neutron-rich Superheavy Nuclei. This system is designed to provide recyclable and high-purity helium for the gas cell. With a series of tests, the cryogenic purification system has been proven to be able to purify the 99% helium gas to 99.999% or higher, fulfilling the requirements of the gas cell when used in conjunction with the chemical purification system.