Bruker RS, Service Manual, Page: 52 / 157

52 ZTKS0156 / Z31820 / Rev.: 03
Assembling
4.3.2.3 Generating the Vacuum
Figure 4.29: Generating the Vacuum
1. Connect the vacuum pumping unit with the
KF connector to the KF 40 flange (6) of the
Vacuum Valve (2). Use a short pump line
with large diameter.
2. Pull out the valve stem (7) of the valve body
(2) to release the sealing plug (1) out of the
bottom plate (3).
The sealing plug (1) snaps into place. The
snapping is well defined and will be heard
and felt. The cryostat is open after this pro-
cedure.
3. Pump and flush five times with dry nitrogen
gas (only necessary for generating vacuum
for the first time).
4. Generate a vacuum of 10
-4
bar with the
roughing pump.
5. Generate a vacuum of less than
5 x 10
-8
bar with a turbo pump (up to
48 hours).
6. The pumping unit has to be operating until
liquid helium filled inside the helium vessel,
respectively until the magnet inside is at a
temperature of 77 K.
7. At the end of the helium filling procedure
push the valve stem (7) slightly and fully into
the valve body (2) to insert the sealing plug
(1) in the vacuum flange at the bottom plate
(3).
The sealing plug (1) snaps in. The snapping
is well defined and will be heard and felt.
8. Stop pumping.