Mirror positioning systems

The precision and accuracy with which X-ray focusing mirrors are positioned are crucial to all experiments on the beamline. The mirror positioning system needs to reflect the relevant photon beam from the storage ring without the interference of vibrations from the environment. Selection of the desired beam redirection requires submicron size linear translations as well as pitch, roll and yaw motions in the microradian range.

JJ X-Ray mirror positioning systems are created with a focus on thermal and mechanical stability. Our design is based on the use of granite, which is well-known for its vibration dampening properties and has a relatively low heat conductivity. Furthermore, an over-constrained mechanical arrangement that ensures a high first eigenmode, while still allowing for optic adjustments in the nanoradian range. Mirror positioning systems are offered in both Ultra and Extreme High Vacuum (UHV and XHV) compatible designs.

The movement of the systems consists of two components: the course motions are achieved by stepper motors and the ultimate resolution of the optics is achieved by using fine pitch piezo driven flextures. Absolute optical encoders ensure high precision measurements of the position and thereby provide control over the movements.

Prior to shipping, all our systems are subjected to extensive factory testing including vacuum tests, parasitic motion measurements, vibration characterization and overpressure testing of water circuits. On-site installation and alignment of the mirror positioning system are facilitated by the incorporation of the preferred fiducial marks, mounted relative to the coordinate system specified by the facility.

Our base design is highly customizable and can be adapted to most specifications in terms of number of moving axes, ranges of the motions, cooling and heating requirements, amounts and sizes of flanges and other connections. This way, the design allows for tailored bending (one-, two- or multi-actuated). Optics with an angular sensitivity ranging from 5 to 50 nanoradians can be included in the offer, or the design can be tailored to accommodate a mirror of choice. A programmable logic controller (PLC) can be included, or the system can be connected to a present infrastructure.