Octupole electrode pattern for tuning forks vibrating at the first overtone mode in quartz-enhanced photoacoustic spectroscopy

摘要

We report on a comparison between two quartz tuning forks (QTFs) employed for quartz-enhanced photoacousticspectroscopy (QEPAS) having quadrupole and octupole electrode pattern configurations. With respect to the quadrupole,the implementation of the octupole pattern suppresses the fundamental mode and reduces by a factor of ～ 4.4 theelectrical resistance for the first overtone mode with negligible variations of the related Q-factors. Both QTFs operatingat the first overtone mode were implemented in a QEPAS sensor and the results showed that the octupole configurationprovides a ～2.3 signal enhancement factor.