SF₆ has been recognized worldwide as the main insulating gas for Gas-Insulated Switchgear (GIS). It is often required to accurately and effectively detect typical SF₆ decomposition. In this paper, a sub-ppm-level SO₂F₂ and SOF₂ gas sensor based on photoacoustic spectroscopy (PAS) is proposed and demonstrated. The steel resonant photoacoustic cell with a resonant frequency of 1750 Hz was designed and fabricated. The harmonic detection technique in wavelength modulation spectroscopy was applied to improve the signal-to-noise ratio. A mercury-cadmium-telluride photodetector was added in the PAS system to monitor the input optical power, in order to compensate for the errors caused by power fluctuations. SO₂F₂ and SOF₂ were measured by using distributed feedback quantum cascade lasers at 6648 and 7463 nm, respectively. The results show that the proposed sensor performed with favourable linearity within the dynamic range, and reached the minimum detection limit of 0.22 ppm for SO₂F₂ and 0.28 ppm for SOF₂, which indicated its great potential for monitoring the decomposition process of SF₆ in GIS.

中文翻译：

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基于光声光谱对 SF6 分解产生的亚 ppm SO2F2 和 SOF2 进行光气传感

SF ₆已被公认为气体绝缘开关设备 (GIS) 的主要绝缘气体。通常需要准确有效地检测典型的 SF ₆分解。在本文中，提出并演示了一种基于光声光谱 (PAS)的亚 ppm 级 SO ₂ F ₂和 SOF _{2气体传感器。}设计并制作了谐振频率为1750 Hz的钢制谐振光声电池。应用波长调制光谱中的谐波检测技术来提高信噪比。PAS系统中增加了一个汞镉碲光电探测器来监测输入光功率，以补偿功率波动引起的误差。所以₂ F ₂和SOF ₂分别使用6648和7463 nm的分布式反馈量子级联激光器测量。结果表明，所提出的传感器在动态范围内表现出良好的线性，对SO ₂ F ₂的最低检测限为0.22 ppm，对SOF _{2的最低检测限为0.28 ppm，表明其在监测SF 6}分解过程方面具有巨大潜力。在地理信息系统中。