Study on the effect of HF acid etching on the quality factor and frequency split of fused silica hemispherical resonators

Abstract

Hemispherical resonator gyroscope is one of the world's most reliable inertial sensors with the longest life span, and has a broad application prospect in aerospace, aviation, vehicles and other navigation fields. The quality factor of hemispherical resonators directly determines the working performance of the hemispherical resonator gyroscope. In this paper, we propose a model to predict the quality factor after grinding by removing subsurface damage of hemispherical resonators by HF etching. We also study the variation law of frequency split of hemispherical resonators in the etching process. The frequency split and quality factor are detected by using frequency sweep and vibration decay methods. The results show that HF etching can raise the quality factor from <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\boldsymbol{5\times 10^{4}}$</tex> to <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\boldsymbol{3\times 10^{6}}$</tex> and the variation pattern verifies the accuracy of the proposed model. The results obtained indicate that the effect of acid etching on the frequency split of the hemispherical resonator is not negligible.