Cryogenic actuator for subnanometer positioning

摘要

This paper discusses the development, realization, and qualification of a positioning actuator concept specifically forcryogenic environments. Originally developed for quantum physics research, the actuator also has many applications inastronomic cryogenic instruments to position optical elements with nanometer level accuracy and stability. Typicalapplications include the correction of thermally induced position errors of optical components after cooling down fromambient to cryogenic temperatures or sample positioning in microscopes.The actuator is nicknamed the ‘PiezoKnob’ because it is piezo based and it is compatible with the typical manipulatorknob often found in standard systems for optical benches, such as linear stages or tip/tilt lens holders. Actuation withhigh stiffness piezo elements enables the Piezoknob to deliver forces up to 50 Newton which allows relatively stiffguiding mechanisms or large pre-loads. The PiezoKnob has been qualified at 77 Kelvin and was shown to work down to2 Kelvin. As part of the qualification program, the custom developed driving electronics and set point profile have beenfine-tuned, by combing measurements with predictions from a dynamic model, thus maximizing efficiency andminimizing power dissipation. Furthermore, the actuator holds its position without power and thanks to its mechanicallayout it is absolutely insensitive to drift of the piezo elements or the driving electronics.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.