Terminology glossary
Environmental Conditions
attocube’ s nanopositioners can be used in different environmental conditions such as ultra-high vacuum. One or more suitable suffixes in the article name describe the environment for which a nanopositioner is designed and tested in-house. Moreover, all ANP nanopositioners are suitable for measurements in a magnetic field as they are built of completely non-magnetic materials.
• / RT – Room Temperature
/ RT positioners are manufactured for use at ambient conditions( room temperature, dry atmosphere, ambient pressure).
• /( U) LT –( Ultra-) Low Temperature
These positioners are suitable for repeated cooling and operation in cryogenic temperatures.
• / HV – High Vacuum
At attocube the high vacuum range is specified down to 1 x 10-8 mbar.
• / UHV – Ultra-High Vacuum
The ultra-high vacuum range is specified down to 5 x 10-11 mbar for most of our 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 1 x 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 attocube’ s nanopositioners are available in open and closed loop versions.
• Open Loop Positioning
In this mode, the positioner is simply driven forward or backward, without an encoder to read back the actual position or a feedback loop to control the desired target position.
• Closed Loop Positioning
Positioners with an integrated encoder(/ RES, / RES + or / NUM, / NUM +) can be used for closed loop position control. A feedbackloop 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 Resistive encoder(/ RES) is used for our ANP 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 repeatability 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.
• Optoelectronic Encoder(/ NUM)
The usage of a glass grating and the interpretation of the generated Moiré pattern characterizes the working principle of the / NUM and / NUM + encoder. The measurement refers to the relative sample position with a position resolution of 1 nm and a repeatability of typically 50 nm for most linear stepping positioners. An absolute position information is also available via a reference mark. The +-version / NUM + features a reduced thermal dissipation of only 50 mW making it especially suited for / HV and / UHV positioners. The / NUM and / NUM + encoders are available for our ECS series positioners.