43 
ZTKS0243 / Z31993 / 03
Troubleshooting
Continued from page before
Indicator Possible reason Solution By
Helium bore tube 
and radiation shield 
are not concentric.
Alignment rod is 
loose or broken.
Replace alignment rod 
a
.
Bruker Service
Reduction flange is 
not concentric.
Check orientation. Bruker Service
Vacuum Valve 
collides with the 
magnet stand.
Vacuum Valve 
collides with the 
magnet stand.
Turn the Vacuum Valve. Be 
careful if the RT vessel is 
evacuated.
Bruker Service
Vacuum in RT 
vessel does not 
reach  
5 x 10
-5
 mbar in 
48 hours.
O-rings may be 
damaged.
Check and clean O-rings and 
slots; replace O-rings if nec-
essary:
• of the Vacuum Valve
• of the drop-off plate
• of the reduction and 
sealing flanges
• of the bottom plate 
a
Bruker Service
Defective pumping 
unit or pumping line.
Check pumping unit and 
pumping line:  
A vacuum less than 10
-6
 mbar 
must be reached with a 
closed sealing plug.  
Replace if necessary.
Bruker Service
Room temperature 
bore tube has 
scratches or dust on 
the sealing surfaces.
Check sealing surfaces on the 
room temperature bore tube: 
No scratches and no dust 
should be visible.
Bruker Service
Moisture in the RT 
vessel.
Pump and flush the RT vessel 
several times with dry 
nitrogen gas.
Bruker Service
Super insulation 
touches RT vessel or 
bore tube or 
radiation shield.
Super insulation was 
not fixed correctly 
during assembly.
Fix super insulation on the 
outer radiation shield with 
polyester tape 
a
. Carefully 
prevent any connection  
between different vessels or 
bore tubes in the cryostat.
Bruker Service
a. For this work the bottom plate has to be removed. Check the suspension tubes of the helium vessel 
are not broken. Install the safety device for fall protection (not supplied). Contact Bruker Service for 
further information.