Bomem interferometer

The spectrum of (-)-a-pinene as a 50 pm film of neat liquid using a Bomem spectrometer with a polarizing interferometer attachment is a composite of 60 000 VCD scans and 12 000 transmission scans and took 19.5 hours to be measured. A spectrum with comparable signal to noise ratio is shown in Fig. 6.3-9. This was measured in our laboratory with a PEM-based VCD spectrometer and is a composite of only 5000 scans (five blocks of 1024 scans each). The noise estimate shown as the upper trace is the difference between two 5000 scan VCD spectra. 

In the late 1980s and early 1990s, interferometer-based instruments were introduced by companies already producing IR equipment Nicolet, Bomem, Perkin-Elmer, and others. Often, these FT-NIR instruments were merely adapted FT-IRs that were already in existence and were not suited for pharmaceutical samples pure raw materials, blends and granulations, tablets and capsules, and larger plastic containers. 

Interferometer-based Bran Leubbe Bomem, Inc. Buchi Mattson Instruments Midac Corp. Nicolet Instrument Corp. Perkin-Elmer Corp. 

I would now like to discuss some results obtained with interferometers. Absorption and emission spectra of numerous species have been obtained in the region 2000A - lOOOp which covers both electronic and vibration-rotation transitions. As examples, I will show you spectra taken at Ottawa with a Bomem DA3.002 interferometer which has a maximum resolution of 0.004 cm". These spectra Include ... 

Figure 5.16. Double-pendulum interferometer of the type first described by Rippel and Jaacks [18] and used by ABB-Bomem in their MB series instruments.

FT-IR Optical Interface. The optical interface employed an aluminum base-plate attached to a Bomem MB-155 interferometer (see Figure 5). The baseplate extended over the burner and supported a deuterated triglycine sulfate (DTGS) detector. A hole was located in the middle of the base-plate to pass the flame. Two mirrors were mounted on pitch and yaw stages to transmit the infrared beam from the interferometer through the flame to an off-axis parabolic mirror,... 

We at Bomem have taken this evolution a step further by providing a completely actively controlled interferometer so that external perturbations such as temperature changes and vibrations are immediately corrected for. In addition to this immunity to perturbations, the active control, which includes automatic alignment acquisition, obviates the need for manual tuning of the interferometer mirrors a task which is often tedious. Finally the precision of.alignment that can be maintained during operation far exceeds that of more conventional interferometers thus leading to extensions of the technique not possible otherwise. 

In the Bomem F.T. spectrometer the simplicity of the flat mirror interferometer is maintained while at the same time compensating for errors in the orientation of the moving mirror by means of an active servo controlled tilt adjustment system. 

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