CC7

The CC7 is a compact continuous ~300mK sorption cooler that is designed to interface to a low-power GM cryocooler. The CC7 has two helium 3 and two helium 4 modules. Each 3-4 module set works like a conventional two-stage (GL7) single-shot sorption cooler. The two ‘sides’ of the CC7 are cycled alternately to keep the central split condenser permanently cold. The split condenser is the cold head of the CC7.

The CC7 is run under software control to operate the switching sequences required to keep the unit running indefinitely. The CC7 split condenser shows small temperature fluctuations when the cycle hands over from one side to the other. There is considerable scope for the end-user to smooth out these fluctuations; the best optimisation scheme will depend on the cryogenic environment and on the heat load this imposes on the CC7. Residual fluctuations can be smoothed out using PID feedback to a load resistor mounted on the split condenser, though this will increase the average temperature of the split condenser.