Bruker RS - Page 78

78
ZTKS0156 / Z31820 / Rev.: 03
Assembling
7. Insert the other side of the helium transfer line into the helium transportation dewar
slowly. Fast insertion of the warm transfer line causes evaporation of helium and
may cause overpressure inside the transportation dewar.
8. Adjust a pressure of 0.1 - 0.2 bar (1.5 - 3 PSI) at the helium transportation dewar.
=> Helium transfer starts.
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Time for cooling down to 4.2 K with helium will take 4 to 6 hours.
9. Use the IBT temperature sensor to monitor the cooling down (see chapter Appendix
Tech n i c a l D a t a ) .
10. Stop helium transfer at a helium level of 100 % at the helium level sensor and 4.2 K
at the IBT temperature sensor.
11. Remove the pumping unit and the vacuum valve (refer to ”Removing the Vacuum
Valve” on page 4-53).
12. Close the stop valve at the cold head turret and remove the helium gas transporta-
tion dewar.
13. Mount the supplied connector (1) to the helium flow system and connect the con-
nector with the stop valve at the cold head flange (3).
14. Open the stop valve at the cold head flange (3).
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If the magnet system will be energized during the next 24 h, the current lead can remain
in the current lead turret. Otherwise continue.
15. Remove the plug out of the turret cap of the helium fill-in turret.
16. Insert the auxiliary shorting plug into the helium fill-in turret.
17. Remove the current lead out of the current lead turret.
18. Insert the shorting plug into the current lead turret with the shorting plug tool respec-
ting the correct position. The shorting plug can only be inserted in one position.
19. Close the current lead turret with the baffle tube, O-ring and screw cap.
20. Remove the auxiliary shorting plug out of the helium fill-in turret.
21. Close the helium fill-in turret immediately with the plug of the turret cap.
22. Record the filling session (see Appendix, Technical Data).
23. Observe the temperature of the outer radiation shield at the External Temperature
Control Unit. The radiation shield will reach its usual operation temperature after
four days operating. Turn on the alarm from the console and the External
Temperature Control Unit if the magnet system is at set operation temperature.