Molecular simulation on adsorption of helium by activated carbon in 4-10 K

In the liquid helium temperature region, the specific heat of helium increases rapidly, so adsorption behavior of helium on activated carbon is expected to be used in the regenerator of 4-K class cryocoolers to improve the performance of the refrigerator. In this paper, we use Grand Canonical Monte Carlo method to simulate the adsorption of helium on the amorphous carbon in 4-10 K. And the structural parameters of amorphous carbons and the effect of temperature, pressure, graphite slice's size and density of amorphous carbon on the adsorption amount were analyzed. The results show that the amorphous carbon constructed from the larger size graphite slice has a smaller specific surface area and a larger pore volume. And as the temperature decreases and the pressure increases, the amount of adsorbed helium increases. In addition, we have found that mixed-filled amorphous carbon can obtain higher specific surface area and pore volume, and has better comprehensive properties.