Cryogenic Nanopositioners & CryoAFM
RENAISSANCE SCIENTIFIC CRYOGENIC NANOPOSITIONING STAGES
A nanopositioner is a piezo driven motion stage that very commonly employs the slip-stick principle. Ranges of motion are typically millimeters (5, 15 and 20 mm travel options available). While minimum step sizes can be small (single nm are achievable).
The Ren-Sci motors were designed to have much lower capacitance than conventional solutions for cryogenic motors. Competitor motors run lower voltages (30-70V) and higher currents (10s of Amps). Ren-Sci chose to do the opposite; their voltages are 50-600 V and source only 100s of mA, reducing heat load.
The Renaissance Scientific Cryogenic Nanopositioning Stages are compatible with the Quantum Design, Montana Instruments Cryostats and Janis Research Cryostats that we offer.
Renaissance Scientific have redesigned the way to run cryo-nanopositioners with a view to reducing heat load.
By running their stages at higher voltages (lower currents) they are able to reduce ohmic heating into the system. It is typical for cryogenic wiring from feedthrough to experiment to have several Ohms resistance. So the Joule heating from drive currents is non-negligible, especially on cryostats with low cooling power on the second stage.
Renaissance are also able to run with 3 orders of magnitude lower capacitance than competitors who use lower drive voltages. Meaning that Renaissance stages can run at much lower powers resulting in less heat dissipation.
FEATURES
UHV AND NON-MAGNETIC BY DEFAULT
All Ren-Sci motors are UHV compatible, bakeable to 120 C, and made with non-magnetic materials. In addition, they’ve integrated all of these UHV and non-magnetic components into production, so there’s no ‘up-charge’ for having these features. No lubricants are used, solid-state or otherwise. Instead, Ren-Sci uses diamond polished surfaces and extremely high precision on their machined parts (sub 2um parallelism on every part), so that there is no need for the use of lubricants.
PURPOSE BUILT FOR CRYO
Several suppliers for ambient piezo based motors will simply try to ‘plop’ it in a cryostat and hope for the best. Ren-Sci motors were carefully engineered with extreme attention to thermal contraction, capacitance losses in cryo, minimal friction at the bearing interfaces, and low current operation as described above. In addition, they engineered a very strong thermal pathway directly beneath the bearing surfaces and the actuator so that heat lift from the motion is swift.
Ren-Sci have had experiences previously as customers of some of these vendors where a motor would seize up at 4K, they called the vendor and they asked Ren-Sci to increase the voltage and/or frequency to try to self-heat its way out of the problem. Ren-Sci motors never seize at 4K.
USER REPLACEABLE ACTUATORS
Think of the piezo actuator as the engine of the nanopositioner. Piezo actuators die. A lot. And it’s usually not the fault of the user nor the vendor who sold the motor – it’s physics. Ren-Sci have taken the approach that the piezo actuator should be thought of as a pseudo-disposable. As such, they have intentionally designed the motors to have user exchangeable actuators and Ren-Sci supply 2 extra actuators per axis. So, each axis should easily last 7-10 years, even under heavy use. But even if you go through those sooner, just call us and we’ll overnight you another actuator. Your days of waiting 6 weeks for a repair are over!
For more information see https://qd-uki.co.uk/cryogenics/renaissance-scientific-cryogenic-nanopositioning-stages/
RENAISSANCE SCIENTIFIC CRYOGENIC ATOMIC FORCE MICROSCOPES
Based on their innovative nanopositioner stages, Renaissance Scientific have brought to the market a solution for bringing AFM to the Cryo domain. With IR, Cantilever and Diamon NV Centre options, these solutions really are at the leading edge.
Renaissance Scientific has qualified the Quantum Design OptiCool for SPM, Ren-Sci will guarantee performance of their AFMs with the OptiCool. Most liquid helium cryostats are compatible, though check with us to make sure.
For example:
Montana Instruments CryoAdvance™
Montana Instruments Cryostation Optical Cryostat S200
Janis Research Cryostats
For more information see https://qd-uki.co.uk/cryogenics/rscns/
