Abstract. We present a compact, affordable and robust instrument based on Incoherent Broadband Cavity Enhanced Absorption Spectroscopy (IBBCEAS) for simultaneous detection of NOx, IO, CHOCHO and O3 in the 400–475 nm wavelength region. The instrument relies on the injection of a high-power LED source in a high-finesse cavity (F ∼ 36,100), with the trans- mission signal be detected by a compact spectrometer based on a high-order diffraction grating and a CCD camera. A minimum detectable absorption of 1.8 × 10−10 cm−1 was achieved within ∼ 22 minutes of total acquisition, corresponding to a figure of merit of 7.5 × 10−11 cm−1 Hz−1/2 per spectral element. Due to the multiplexing broadband feature of the setup, multi-species detection can be performed with simultaneous detection of NO2, IO, CHOCHO, and O3 achieving ultimate detection limits of 9, 0.3, 8 ppt and 40 ppb (1σ) within 22 min of measurement, respectively (half of the time spent on the acquisition of the reference spectrum in absence of absorber, and the other half on the absorption spectrum). The implementation on the inlet gas line of a compact ozone generator based on electrolysis of water allows the measurement of NOx (NO + NO2) and therefore an indirect detection of NO with detection limits for NOx and NO of 12 and 21 ppt (1σ), respectively. The device has been designed to fit in a 19′′, 3U rack-mount case, weights 15 kg and has a total electrical power consumption
Supplementary material to "A compact Incoherent Broadband Cavity Enhanced Absorption
Spectrometer (IBBCEAS) for trace detection of nitrogen oxides,
iodine oxide and glyoxal at sub-ppb levels for field application"
