Maintaining detector dewar

If your instrument has a cooled detector, it will include a detector dewar. With proper care, a detector dewar should maintain its insulating vacuum for many years. If the vacuum leaks, the insulation will lose effectiveness and the following symptoms may occur:

• Liquid nitrogen boils off much faster than usual.
• The outside of the dewar stays cold more than 30 minutes after filling and may feel damp or become frosted.
• Water and atmospheric contaminants condensing on the detector window show up in spectra as unwanted peaks.