| Lines 8-9 were replaced by lines 8-9 |
| - normally in order to fill the pumping volume with some |
| - amount of liquid helium. Put "flow" of 20 mbar until the |
| + usual in order to fill the pumping volume with some |
| + amount of liquid helium. Put a "flow" of 20 mbar until the |
| Lines 12-22 were replaced by lines 12-23 |
| - (the pressure decreases only slowly). Then regulate the |
| - valve at about 10 mbar. This value must not be obeyed exactly, |
| - the idea behind the needle valve settings is the following: |
| - ** A lower flow is better for consumption (a "flow" of more |
| - than 10 mbar increase substatnitally the He consumption, but |
| - during the process of condensing it might be o.k.). |
| - ** The flow should be high enough to hold the 1 K pot temperature |
| - low (over long term: about 2 K with the Variox and about 2.5 K |
| - with the MA09). During the condensing phase, the 1 K pot temperature |
| - might increate to 3.5 K for a short time, when pushing the |
| - mixture quickly. |
| + (this takes some time, as the pressure decreases only slowly). |
| + Then regulate the valve at about 8 mbar. This value must not |
| + be obeyed exactly. In principle, the best needle valve setting |
| + is reached, when the 1 K pot temperature (not the VTI temperature!) |
| + is minimal. Hours might be spend to optimize the |
| + needle valve opening, a better idea is take somthing between 8 and |
| + 10 mbar as a good starting point, and optimize later, if necessary. |
| + It should be possible to achieve a 1 K pot temperature of |
| + about 2 K with the Variox and about 2.5 K with the MA09. |
| + However, when condensing the mixture, the 1 K pot temperature |
| + might increase to 3 to 4 K for a short time, when pushing the |
| + mixture quickly. |
| Line 30 was replaced by line 31 |
| - * Open valve 9 (while pressing on the black valve button, press |
| + * Open valve 9 (while pressing on the valve button, press |
LIN