Specific Heat of LiquidHe3in Sintered Copper below 3 mK

Abstract

A nuclear cooling system consisting of copper wire was connected to a copper container inside of which a copper powder had been compressed and sintered. The heat capacity of the system without ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ in the container was subtracted from the heat capacity with ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ at pressures ranging from 0 to 29 atm. The difference shows a peak at 1.5 mK which decreases in magnitude as the pressure is reduced and a broad shoulder extending up to about 3 mK which is present at all pressures.