Detector Translation Unit (DTU)
The detector translation mechanisms of EMIR, includes both focusing capability and XY positioning. It will permit active compensation of the internal flexures of the instrument, attached to the Nasmyth rotator and could also be used to implement advanced features in the observing strategy.
It is necessary to move the detector in 3 axis: Z axis provides the capability of refocusing the image. X and Y axis movements allow for compensation of the image movement in the focal plane, achieving a stable incidence onto the detector. In addition, the system can combine simultaneously these compensation movements (fine mode) with other operation modes useful for astronomical purposes (raw mode).
Axis |
Range |
|---|---|
| X-Y Fine mode | ±50 µm |
| X-Y Raw mode | ±400 µm |
| Z (focus) | ±2.0 mm |
The mechanism, which will physically effect the 3D motion of the detector, composed of the following main components
- The base structure, which interfaces with the Optical Bench (OB) and supports the three translation stages
- The translation stages, three identical units, which provide linear motion along the Z direction
- The kinematic structure, which through its kinematic links consisting of flexure rods, transfers the motion to the detector interface plate, obtaining pure XYZ displacement with practical absence of any tilt.
- Temperature sensors
The electronics and control system:
- Motor controller (3-axis)
- Controller software
- Software for combined DTU moves
- Temperature sensors signal conditioning electronics
- All cables and connectors for cryo and room environment.
