Date: 9/5/2024
White Bear Photonics, LLC
2157 Randy Ave
White Bear Lake, MN 55110
Summary
Thermo Nicolet FTIRs are often left powered ON according to the user manual. This means both the laser and IR source are on during this time. In addition to providing Mid IR light, the IR source also acts as an oven and will reduce the humidity level within the instrument. When FTIR instruments are left on 24/7 the typical lifetime for an IR source is 1-2 years. The question often asked, if one only uses the FTIR 1-2 times a week should it be left on 24/7? We recommend if the desiccant is well maintained (or purged with dry air) and assured the instrument is dry on the inside, then the unit can be powered off and only turned on when needed if less the 2-3 times per week.
Replacement of the IR source is often needed due to:
- Low amplitude in the Interferogram (Max is less than 2 at Gain=1). Often times an error will occur (warning) during startup in Ominic, stating low amplitude.
- Higher RMS noise levels will occur in the performance tests as shown in the advanced diagnostics or in Valpro.
Installation
Installation is very simple. There are three small Philips screws and a handle to pull and replace the IR source.
- Turn off FTIR and locate the IR source (see picture).
- Re-install the new source. Notice the notch on the source, it can only go in one way.
- Power the FTIR up.
- Go into Ominic > Experiment Setup > Diagnostics tab, then hit Align.
- This will maximize the interferogram. Record the interferogram Maximum in your log book and the date the IR source was installed. This can be used for future reference if/when your signal to noise drops or low amplitude error occurs.
- If you periodically need to validate your FTIR with Valpro, it is usually re-validated the time the new IR source is installed.
- Change out the desiccant pack, if you system is not purged with dry air.