Reduction of temperature fluctuation within low temperature region using a cryocooler.

Area of Science:

• Low-temperature physics
• Materials science
• Cryogenic engineering

Background:

• Gifford-McMahon (GM) cryocoolers exhibit temperature fluctuations due to displacer motion.
• Minimizing temperature fluctuations is crucial for sensitive low-temperature experiments.

Purpose of the Study:

• To decrease temperature fluctuation in the low-temperature region of a GM cryocooler.
• To investigate the effectiveness of fiber-reinforced plastic (FRP) dampers for thermal stabilization.

Main Methods:

• One-dimensional heat equation modeling to identify key factors for reducing temperature fluctuation.
• Experimental implementation of FRP dampers with varying thicknesses on the cryocooler's cryohead and sample stage.

Main Results:

• Low thermal diffusivity of FRP was identified as essential for reducing temperature fluctuations.
• FRP dampers dramatically reduced temperature fluctuations, achieving 0.7 mK with a 0.25 mK standard deviation at 4.2000 K.
• Initial temperature fluctuations of 282 mK at the cryohead were significantly mitigated.

Conclusions:

• Fiber-reinforced plastic dampers are highly effective in stabilizing temperatures in GM cryocoolers.
• The study demonstrates a practical method for achieving ultra-low temperature fluctuations for demanding applications.
• This approach enhances the performance of GM cryocoolers for precision scientific research.