摘要 |
A portable camera system (100) includes a lens (104) for forming a focused image of a survey scene (106) onto a focal plane array (108). The focal plane array (108) comprises a cooled two dimensional array of quantum well infrared photo detectors, (QWIP) having a peak spectral responsivity in the wavelength range of 10.4 to 10.8 mum. The camera includes a cooled band pass optical filter (110) having a peak spectral transmittance approximately centered at a wavelength of 10.57 mum and a full width half maximum spectral transmittance bandwidth of approximately 10.3 to 10.7 mum. The camera system (100) is usable to detect an invisible gas plume in a video image of a survey scene if the gas plume contains sulfur hexafluoride (SF6), ammonia, (NH3), Uranyl Fluoride (U2O2F2), or any other gas having an absorption band that that at least partially falls within the wavelength band 10.3 to 10.8 mum. |