...
The fast+slow pre-cooling allows us to reduce the slow pre-cooling time by initially fast pre-cooling the first part of the transfer line and then transit transition to the slow pre-cooling. Figure 2 (right) shows an example of the Tank T behavior of a slow pre-cooling that followed a fast pre-cooling. It is observed that the Tank T temperature drops significantly faster when a fast pre-cooling is initially performed reducing the slow pre-cooling time to about 1 to 2 hours. The efficiency of this procedure is consistent with the standalone slow pre-cooling efficiency minus 1% given by the initial fast pre-cooling consumption of 4 additional liters of LHe on the Liquifier.
...