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Low cost laserless FTIR spectrometer on the farm for real-time nitrous oxide soil emission measurements

Low cost laserless FTIR spectrometer on the farm for real-time nitrous oxide soil emission measurements

Category
Journal publication
Abstract
A low-cost Fourier transform infrared (FTIR) instrument was developed where the traditional He–Ne reference laser was replaced by a low-cost linear encoder. An RMS sampling error of less than 20 nm was achieved by oversampling both the interferogram and the encoder signal and then resampling the interferogram using a correction table for the encoder. A gas calibration model was developed for the system, which was chosen to have a stroke length of 21 mm and, thereby, a resolution of 0.4  cm −1 after apodization. The instrument was mounted on a vehicle and employed in an agricultural field test for measuring soil emissions, in particular nitrous oxide (N 2 O ). The concentration of N 2 O was measured with a root mean squared error of 6 ppb. The results compared well with lab-based gas chromatography measurements.
Language
English
Author(s)
Affiliation
  • SINTEF Digital / Smart Sensor Systems
  • SINTEF Digital / Microsystems and Nanotechnology
  • Norwegian Institute of Bioeconomy Research
Year
2013
Published in
Applied Optics
ISSN
0003-6935
Publisher
Optical Society of America
Volume
52
Issue
4
Page(s)
93 - 101