ANITA—An active vibration cancellation system for scanning probemicroscopy

The high sensitivity of scanning probe microscopes poses a barrier to their use in noisyenvironments. Vibrational noise, whether from structural or acoustic sources, can manifestas relative motion between the probe tip and sample, which then appears in the probeposition (“Z”) feedback as it tries to cancel this motion. Here we describe an activecancellation process that nullifies the appearance of this vibration by adding a drivesignal into the existing Z-feedback loop. The drive is digitally calculated fromaccelerometer-based vibration measurements. By transferring the vibration cancellationeffort to this drive signal, vibration-created noise is significantly reduced. Thisinexpensive and easy solution requires no major instrumental modifications and is idealfor those looking to place their microscopes in noisier environments, coupled, forexample, to active refrigeration systems (e.g., pulse tube cryocoolers) or otherhigh-vibration instruments.