Quartz Enhanced Photoacoustic Spectroscopy for Detection of Improvised Explosive Devices and Precursors

Figure 13

QEPAS response at the peak absorption wavelength of nitromethane at 7254 nm. The flux of a mix of nitromethane at 7 ppm and water vapour was switched on and off at several times, as indicated by the arrow in the plot. The QEPAS signal increased and decreased accordingly.