Quality factor of torsional resonators in the low-pressure region

This paper reports the calculation of the Q-factor of a torsional resonator in the low-pressure region if the vibration occurs in free space or close to another surface. The calculation is based on the model used by Christian but a modified Maxwell-Boltzmann distribution, the Maxwellian-Stream distribution, is applied to describe the velocity distribution of the gas particles colliding with the resonator. The result is an increased damping factor or lower quality, which matches much better with published measurements.