Russian doll type cryogenic traps:  improved design and isotope separation effects

Area of Science:

• Analytical Chemistry
• Environmental Science
• Chemical Engineering

Background:

• Efficient removal of condensable gases is crucial for gas mixture analysis and purification.
• Existing cryogenic traps may have limitations in trapping efficiency, flow rate handling, or substance retrieval.
• The Russian doll design offers potential for enhanced performance in gas trapping applications.

Purpose of the Study:

• To describe an improved cryogenic trap based on the Russian doll design.
• To evaluate its trapping efficiency for micromole quantities of condensables at high flow rates.
• To investigate the retrieval of condensed substances and isotopic separation effects.

Main Methods:

• Utilized a demountable Russian doll cryogenic trap with nested glass fiber thimbles.
• Tested trapping efficiencies with carbon dioxide (CO2) at flow rates up to 10 L/min.
• Investigated isotopic enrichment and gas chromatographic effects using helium (He) as a carrier gas.

Main Results:

• Achieved extraordinary trapping efficiencies with the improved Russian doll design.
• Demonstrated quantitative retrieval of condensed CO2 despite the large fiber area.
• Observed minimal dependence of trapping efficiency on coolant level and a small isotopic enrichment in 13C.
• Discovered a gas chromatographic effect for carbon monoxide (CO) with helium carrier gas, leading to significant isotope separation.

Conclusions:

• The improved Russian doll cryogenic trap offers high performance for removing condensable gases.
• The design facilitates quantitative retrieval and exhibits interesting isotopic separation phenomena.
• This technology has implications for gas analysis, purification, and isotope studies.