PerkinElmer LS 55, Руководство пользователя

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116 . LS 55 User’s Guide
9. Tighten the four securing screws.
During this, the position of the sample tube may shift slightly. Confirm that
the signal is as high as the maximum seen during alignment. If not, repeat
the alignment process above.
10. Remove the sample tube from the sample holder block and replace the black
foam block.
11. Place the black metal securing strip on top of the foam block, and secure it
using the two screws removed previously.
12. Replace the top cover of the accessory.
Purging the instrument
Before measurement at liquid nitrogen temperatures can be performed, the
instrument must be purged with dry gas, for example helium or nitrogen. This gas
must be free of carbon dioxide and moisture.
The purpose of purging is to avoid the build-up of ice on optical surfaces inside the
instrument, in the sample area and on the sample tube itself. A gas flow rate of 0.5
L/min is normally sufficient.
The gas flow must be connected to the purge nozzle under the instrument as
shown in Figure 111.
Figure 111 Location of the purge nozzle
Purge nozzle