system in order to anticipate the increased cooling requirement before its effect on the component 1 is observed thus by virtue of the invention the change in the cooling power regime occurs in such a way that the maximum power of the refrigerator is immediately available when the increased thermal load appears preferably the change in the cooling power for example achieved by changing cycle pressures and or flow rates is not abrupt not an all or nothing variation but is gentle for example the variation being at least partially smoothed fig3 illustrates operation of this type the increase in the cycle pressure p to increase the cooling power of the device 2 the maximum pressure is set to setpoint pmax as a function of time u201c t u201d precedes the signal pa representing a plasma peak of the curve pa fig3 also shows a curve t 1 representing the variation in the thermal load that the component 1 applies to the liquid helium reserve 4 i e this load curve t 1 represents the heat to be dissipated from the component 1 when the thermal load t 1 applied by the component 1 again decreases the pressure setpoint p may be reduced in an optimal way preferably at the same rate as the load until the low pressure setpoint minimum pressure is reached in this operating mode excess cooling power is provided for a short time before the effective increase in the thermal load this excess thermal power may be regulated by a heater that vaporizes any excess liquid produced or via a cold bypass system that returns some of the helium from the cooling unit to the compressing station.