In usual multi-anvil cell assemblies, effective thermal insulation is made to improve the heating efficiency. The increase in heating efficiency slows the cooling rate upon quenching. We
therefore attempted to increase the quench rate by decreasing thermal inertia as follows.
The heaters are surrounded by high thermal conductivity material, namely W, connected to the second-stage anvils.
The whole cell assemblies including the second-stage anvils are kept in a coolant.
By these innovation, we have succeeded in increasing the cooling rate by one order of magnitude.