| Lines 6-7 were replaced by lines 6-8 |
| - |
| - * On the Variox or Magnet VTI, open the needle valve more than |
| + * Cool the 1 K pot to a temperature below 3 K. With the |
| + Variox 2 K may be reached, with MA09 about 2.5 K. |
| + It might be necessary to open the needle valve more than |
| Lines 9-24 were replaced by lines 10-12 |
| - amount of liquid helium. Put a "flow" of 20 mbar until the |
| - 1 K pot temperature is stable below 3 K. Then close |
| - the needle valve until a "flow" of about 10 mbar is reached |
| - (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. |
| - |
| + amount of liquid helium. Be aware, if the amount of |
| + liquid is too high, it might take hours to get a stable |
| + flow. |
| Line 32 was replaced by line 20 |
| - RAISE). |
| + RAISE). |
| Line 41 was replaced by lines 29-33 |
| - |
| + * During condensation, the 1 K pot temperature might raise to more than 3 K, |
| + especially when the pressure on G1 is high. Adjusting the needle valve |
| + is only necessary, when this temperature get too high and prevents |
| + the condensation to progress. |
| + |
LIN