Terminology glossary
Environmental Conditions
attocube cryogenic nanopositioners are made for different environmental conditions such as ultra-low temperature or ultra-high vacuum. One or more suitable suffixes of the article name describes the environment for which a nanopositioner is designed and tested in-house. Moreover, all cryogenic nanopositioners are suitable for measurements in a magnetic field as they are built of completely nonmagnetic materials.
• / LT – Low Temperature
These positioners are suitable for repeated cooling and operation in cryogenic temperatures down to 1 K.
• / ULT – Ultra-Low Temperature
For measurements going beyond 1K: these positioners come( if desired) with a special resistive sensor and are made from berrylium copper( BeCu) instead of titanium.
• / HV – High Vacuum
The high vacuum range is specified down to 10-8 mbar.
• / UHV – Ultra-High Vacuum
The ultra-high vacuum range is specified down to 5x10-11 mbar for most positioners. A few rotators and goniometers use UHV compatible grease. Due to the increased outgassing of these types at elevated temperatures we specify them for 10-9 mbar as a precaution( noted in specification sheets). Most of our positioners can be baked out up to 150 ° C.
Position Control
Most of the cryogenic nanopositioners are available in open and closed loop versions.
• Open Loop Positioning
The positioner is simply driven forward or backward, without an encoder reading the actual position.
• Closed Loop Positioning
Positioners with an integrated encoder(/ RES, / RES +) can be used for closed loop position control. A feedback loop integrated into the control electronics minimizes the difference between target position and actual position. Setpoints can either be defined in a software interface or on the front panel of the electronics.
• Resistive Encoder(/ RES)
A resitive encoder used for our cryogenic nanopositioners. The working principle of this encoder type is based on a potentiometer. It is the method of choice for applications at cryogenic temperatures, ultra-high vacuum and highest magnetic fields. The / RES encoder measurement refers to the absolute sample position, for most linear steppers a precision of 1 μm is achieved. For ultra-low temperatures( T < 1 K) a special / RES + sensor is available which is included in all our / ULT models.