基于泛频振动的石英增强光声光谱测声器优化设计

Optimization of Overtone Resonance Based Quartz-enhanced Photoacoustic Spectroscopy Spectrophone

为了进一步提高基于泛频振动的石英增强光声光谱测声器探测灵敏度,在一次泛频振动模式下采用一个比商用标准音叉外形尺寸大5倍的定制大音叉,并对其性能进行优化.通过理论和实验研究得出了音叉与激光的最佳作用位置,发现音叉的一次泛频振动有两个波腹点,且在距离音叉根部8 mm处,音叉振臂的振动幅度最大.微型声音谐振腔由三种不同内径的不锈钢毛细管加工而成,与音叉组成共轴配置石英增强光声光谱光谱测声器,用来进一步增强信号幅值.在最佳微型声音谐振腔配置下,获得了30倍的信号增益因子,有效提高了石英增强光声光谱光谱测声器的探测灵敏度.

A custom quartz tuning fork which is 5 times larger than commercial standard quartz tuning fork and operated at the 1st overtone resonance mode was used and optimized to improve the sensitivity of the quartz-enhanced photoacoustic spectroscopy spectrophone.The optimum ecxiting position for the laser beam was researched.Two resonance antinodes were found in the 1st overtone resonance,and the maxium signal amplitude was obtained at a distance of 8 mm from the tuning fork support.Acoustic micro-resonantors with three different inner diameters were configured with the custom tuning fork to evaluate the performance of the quartz-enhanced photoacoustic spectroscopy spectrophone.With an optinal parameters,a sensitivity gain factor of 30 was achieved with respect to the signal amplitude obtained by the bare tuning fork without acoustic micro-resonantors.