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 .