Control of ultralow pressures: an absolute thermodynamic manometer

Area of Science:

• Cryogenics
• Low-temperature physics
• Materials science

Background:

• Precise pressure control is crucial for low-temperature experiments.
• Existing methods may require complex or expensive apparatus.
• The behavior of helium-4 (4He) adsorbed on Grafoil at low temperatures is of scientific interest.

Purpose of the Study:

• To present a novel method for accurate helium gas pressure manipulation.
• To achieve pressure control in the range of 10(-1) to 10(-20) Torr.
• To utilize thermodynamic measurements for pressure calibration.

Main Methods:

• Employing thermodynamic measurements on the 4He-Grafoil system.
• Developing a calibration curve specific to the 4He-Grafoil interaction.
• Establishing a pressure scale for a manometer based on these measurements.

Main Results:

• A method for accurately manipulating helium gas pressure at T<5 K was successfully developed.
• A calibration curve and pressure scale were established for manometer application.
• The technique demonstrated utility in a practical experimental setup.

Conclusions:

• The presented method provides a simple and accurate way to control low-pressure helium gas.
• The developed calibration and pressure scale facilitate wider adoption in research laboratories.
• This technique enhances low-temperature experimental capabilities.