PerkinElmer Spectrum 100 Series User Manual

82 . Spectrum 100 Series User’s Guide
4. Make sure the supplied plastic funnel is dry.
CAUTION
Stand where you can see the inside of the funnel as you pour the
nitrogen in. Pour slowly, so that neither the funnel nor the dewar
overflows. Take care not to overfill the funnel and splash liquid
nitrogen onto the instrument covers.
5. Insert the plastic funnel into the funnel guide and slowly fill the detector dewar with
liquid nitrogen.
NOTE: Make sure that the detector dewar is filled to the top with liquid nitrogen before
selecting the detector. Prevent radiation from reaching the detector by
obstructing the beam path in the sample area during filling.
6. Stand back and wait two minutes.
This nitrogen also vaporizes as the dewar continues to cool. The two-minute wait
allows the bubbling to settle down and the pressure of the vaporizing nitrogen to
dissipate.
7. Continue to pour liquid nitrogen into the funnel, adding a little more each time the
funnel empties.
The funnel takes longer to empty as the dewar fills. This happens after two or three
more funnels of liquid nitrogen. Because the dewar has now cooled, the liquid
nitrogen does not vaporize, but instead fills the dewar.
8. Remove the funnel and wait two minutes.
The liquid nitrogen settles down and bubbling slows.
9. When the nitrogen stops bubbling, refit the plug.
When the detector dewar has been filled, it will remain at its operating temperature
for approximately eight hours.
NOTE: Cooled detector dewars require pumping down after approximately 12 months
operation. When the boil-off rate of liquid nitrogen becomes excessive (that is the
liquid nitrogen level is low after 3-4 hours’ operation), consult the nearest
PerkinElmer Service Department or Agent.

PerkinElmer Spectrum 100 Series Specifications

General

Brand	PerkinElmer
Model	Spectrum 100 Series
Category	Measuring Instruments
Language	English