MicroWave Spectroscopy Laboratory

Instruments RAD Spectrometer  Sensitivity demonstration

Example of recording demonstrating RAD spectrometer sensitivity


“Forbidden” transitions of AsH3 molecule recorded by RAD spectrometer.
The spectrometer sensitivity can be calculated using the line maximum absorption coefficients (shown above) and the recording signal to noise ratio as:

For more details see paper [Ref. 1 (1987)].


Investigation of the 22-GHz atmospheric diagnostic water vapor line using RAD spectrometer. Three hundred experimental spectra (lock-in time constant is 0.5 s) of the mixture of water vapor with argon are shown by grey curves. Averaged spectrum is shown by solid black curve. Pure rotational transition 532-533 of HDO molecule in natural abundance is seen in the upper line wing near 22.307 GHz (shown in the inset). Evaluated sensitivity of the spectrometer is 210-10 cm-1 [Ref. 1 (2018)].




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