title: Low cost "laserless" FTIR spectrometer on the farm for real-time nitrous oxide soil emission measurements.
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.
authors: SINTEF ICT, Oslo, Norway.
authors: Karl Henrik
authors: KH
authors: Haugholt
authors: Matthieu
authors: M
authors: Lacolle
authors: Marion
authors: M
authors: O'Farrell
authors: Atle
authors: A
authors: Honne
authors: Kari Anne Hestnes
authors: KA
authors: Bakke
authors: Aina
authors: A
authors: Lundon