Applications

The quDIS is a confocal displacement sensor with a high signal stability and a contrast independent measurement algorithm. The quDIS is a a laser interferometer configurable as a Fabry-Pérot or Michelson setup. Its high precision is required in various high-end applications in science and industry.

Sample positioning for X-ray diffraction measurements in synchrotron facilities

X-ray crystallography is used to determine the atomic and molecular structure of a crystal. The crystalline structure causes an incident X-ray beam to be diffracted in many specific directions. By measuring the angles and the intensity of these diffracted beams, a three-dimensional image of the electron density in the crystal can be obtained and thus the molecular structure can be identified.

In synchrotrons, charged particles like electrons are accelerated to very high speeds and then laterally deflected once or multiple times at regular intervals by bending magnets and other insertion devices. The X-rays produced by the acceleration of these charged particles are emitted in dozens of thin beams, directed at a beamline adjacent to the accelerator. A synchrotron can generate a much more focused, or brilliant, beam of radiation with highest intensities.

The X-rays in a beamline hit a crystalline sample and get diffracted by its lattice. By rotating the sample through several angles in a vacuum chamber while the X-ray detector measures the diffraction angles, the crystalline structure can be analyzed.

In this application, the quDIS displacement sensor measures the distances between the fixed sensor heads and the sample surface and determines the positioned angles of the sample. It measures the movement of the goniometer stage in a closed-loop setup with sub-nanometer accuracy.

Thermal deformation of a satellite in simulated space environment

A space telescope is superior to a ground-based one because there is no light pollution or atmospheric aberrations, providing a more stable image, and offering unprecedented angular resolution over a large field. The disadvantages are the high costs and difficult maintenance, therefore the design and the construction must be very carefully prepared.

A Cassegrain reflector, like most large professional telescopes, has a parabolic primary mirror and a hyperbolic secondary mirror that reflects light back down through a hole in the primary. The mirrors and optical systems determine the final performance. Optical telescopes typically have mirrors polished to an accuracy of about a tenth of the desired wavelength.

The metering truss, e.g. a graphite-epoxy frame, is the optical telescope assembly and keeps the working parts of the telescope firmly aligned. It must be able to withstand the frequent changes from direct sunlight to the darkness of the Earth’s shadow, resulting in large temperature fluctuations, and at the same time be stable enough to allow extremely accurate alignment of the telescope. It is surrounded by multi-layer insulation that keeps the temperature inside the telescope stable.

The design and materials of the measuring truss and its response to the harsh environment in space must be tested on Earth. By enclosing the entire structure, controlling parameters such as temperature and pressure, and measuring the deformation with multiple quDIS axes, the deformation can be determined under simulated conditions. In this case, twelve quDIS axes were used to measure the deformation of the cylindrical measuring truss in multiple directions with the highest precision and low drift over a long period of time.

Sensor Heads

All applications require different constrains for collimation, focusing and the beam profile, depending on their reflecting targets. The shaping of the laser beam is achieved by different sensor heads. All these sensor heads for quDIS are based on optical fibers, well-established in the telecommunication market.

Next to standard collimators and established focusing heads, qutools designs special heads for applications in harsh environments.

CB 2.3

Collimated beam, standard sensor head

CB 2.3 APC

Collimated beam without reference reflex for individual usage

FF 50

Focused beam with fixed focal length

FA 50-1400

Focused beam with adjustable focal length

MI SR50:50

Michelson sensor head with different splitting ratios SR for different reflecting targets

MI OR SR50:50

Michelson sensor head with open reference and different splitting ratios SR

Accessoires and Upgrades

Distance Measurement

Determination of absolute distances within the wavelength range and compensation beam interruptions.

Ambient Measurement Unit (AMU)

Analysis of environmental parameters like temperature, pressure and relative humidity.
Failure correction, Measurement of refractive index.

quCATCH

Fibre coupling unit for fast and automatic laser coupling.
Quick calibration measurement even at separated locations.

Reflectors

Different reflector solutions: Retroreflectors, plane or parabolic mirrors.
Temperature caused deformation and signal stabilisation.

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