Absolute in-situ calibration piezoelectric quartz tuning fork force Sensors.

A method has been developed for absolute calibration of piezoelectric quartz tuning forks for use as force sensors with nano-newton resolution. The performance of the forks in a cryogenic environment is investigated. The mechanical properties of the forks are extracted from the frequency dependent admittance and compared to the exact model of a vibrating cantilever in a helium atmosphere. The method is verified by simultaneous application of calibrated point loads to the cantilever in vacuum.