Terahertz High Resolution Gas Spectroscopy for the Analysis of the Composition of Products of Thermal Decomposition of Cereal Grains (Oat, Barley)

Systematic errors of THz absorption gas spectroscopy due to interference in a multi-pass cell

“…Spectroscopy provides methods for studying the molecular structure, dynamics, and interactions [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] as well as for determining the chemical composition of a sampled substance. Therefore, such important applications of the analysis of multi-component mixtures as biological investigations [1-16], medical diagnostics [21][22][23][24], food and quality control [25][26][27][28][29][30][31][32][33][34], and heritage science [35] require precise and reliable spectroscopy techniques. However, spectroscopy-based chemical analysis of solids, liquids, or solutions requires complex mathematical signal processing such as chemometric methods [27,28] or wavelet analysis [29] due to overlapping spectral features of different substances.…”

“…Low-pressure gas spectroscopy in THz and cm range is mostly free of the overlapping due to small Doppler line broadening in the ranges [23, 24, 33, 34, and 39]. So, its applications are becoming prospective methods of medical diagnostics [23,24] and food control [33,34]. Multi-pass cells are used in THz gas spectroscopy for holding samples and increasing optical path length [37][38][39].…”