Bruker CryoProbe User Manual

Cold operation problems
CryoProbe User Manual BRUKER 79 (107)
cause it facilitates problem analysis and thus speeds-up the repair process con-
siderably.
CAUTION: If a CryoProbe inside the magnet has ice on it and automatic warm-up
is not already in progress, initiate a warm-up immediately! The magnet bore must
be protected against low temperature exposure. A cold magnet vacuum seal may
become leaky and the magnet could quench. However, do not try to accelerate
the CryoProbe warm-up with e.g. a heat gun!
Sample temperature problems 7.6.5
IMPORTANT: Do not interrupt the VT unit or its gas flow at any time while the
CryoProbe is cold. The sample may cool down to cryogenic temperatures, poten-
tially breaking the sample tube or damaging the substance under investigation.
VT gas must flow through the CryoProbe at all times even if no sample is present
to avoid water condensation.
Sample temperature doesn’t reach preset value
- too cold: verify that the VT heater is O
N. Increase the VT gas flow or the VT
heater power limit but make sure the sample is not lifted.
- too warm: increase the VT gas flow (see minimum flow rate on the ‘L
IMITATIONS
- WARNINGS’ sheet) but make sure the sample is not lifted.
Sample temperature unstable
- Is the VT gas flow sufficient and stable (see minimum flow rate on the ‘L
IMITA-
TIONS - WARNINGS’ sheet)?
- Is the H
IGH/LOW setting on the VT Interface Box appropriate for the desired tem-
perature range (see "Sample temperature control" on page 55
)?
- If a B-VT3000 is available, use its self-tune feature. Obey the limits given on the
‘L
IMITATIONS - WARNINGS’ sheet.
- Is a B-VT3300 or B-VT3200 employed? These units are not recommended be-
cause their temperature regulation is more coarse than that of a B-VT3000, thus
small artifacts could occur in temperature-sensitive experiments. The self-tune
feature on a B-VT3300 does not work properly with a CryoProbe.
Unusual sounds 7.6.6
Is the characteristic periodic noise from the Coldhead missing although the He
Compressor is active? Turn O
FF the main switch at the CryoCooling Unit front and
call B
RUKER.
A mechanical blockage, broken or false wiring of the Coldhead power cable be-
tween CryoCooling Unit and He Compressor could be the cause. Also, the fuses
of the DC 24 V control circuit inside the He Compressor might be blown.
Mains power interrupt 7.6.7
In case of a complete mains power breakdown, all valves in the CryoProbe Sys-
tem will switch back to their default positions such that no over-pressure can de-

Bruker CryoProbe Specifications

General

Brand	Bruker
Model	CryoProbe
Category	Laboratory Equipment
Language	English