A novel coating to avoid corrosion effect between eutectic gallium-indium alloy and heat sink metal for X-ray optics cooling.

Owing to the parasitic vibration effect of the cooling medium and pipes of X-ray optics, the vibration decoupling cooling method based on eutectic gallium-indium (EGaIn) alloy has become very crucial for fourth generation synchrotron radiation advanced light sources. However, there is an issue that the corrosion of the EGaIn alloy to the heat sink metal [e.g.

An improved differential-grating plane-mirror heterodyne interferometer for small roll angle measurement of a linear motion.

In the previous studies on roll angle (ROLL) measurements which are based on the concept of the combination of a diffraction grating displacement technique and a laser heterodyne interferometry, there is always a lack of ideally functional retro-reflectors and corresponding optical configurations resulting in misalignment and unconfident monitoring. To overcome this problem, a differential-grating plane-mirror heterodyne interferometer is proposed in this paper, in which the grating displacement sensing method is utilized to promote angular interferometry as a reliable ROLL measurement. The working mechanism is thoroughly demonstrated through the theoretical derivation and performance analysis.

An algorithm for circular test and improved optical configuration by two-dimensional (2D) laser heterodyne interferometer.

Circular test is an important tactic to assess motion accuracy in many fields especially machine tool and coordinate measuring machine. There are setup errors due to using directly centring of the measuring instrument for both of contact double ball bar and existed non-contact methods. To solve this problem, an algorithm for circular test using function construction based on matrix operation is proposed, which is not only used for the solution of radial deviation (F) but also should be applied to obtain two other evaluation parameters especially circular hysteresis (H).

Note: Optimal choice of the reflector by phase analysis for heterodyne interferometric roll angle measurement.

The choice of an actual reflector instead of an ideal or perfect reflector has to be dealt with for heterodyne-interferometric roll angle measurement methods. The candidates of regular reflectors such as corner cube prism and right angle prism are analyzed by the homogeneous coordinate transformation method, which provides a theoretical basis for the determination of the actual reflector. Furthermore, the influences of the phase loss of the determined reflector are strictly argued due to non-perfect or natural characteristics itself.

Measurement method for roll angular displacement with a high resolution by using diffraction gratings and a heterodyne interferometer.

The roll angle measurement is difficult to be achieved directly using a typical commercial interferometer due to its low sensitivity in axial direction, where the axial direction is orthogonal to the plane of the roll angular displacement. A roll angle measurement method combined diffraction gratings with a laser heterodyne interferometer is discussed in this paper. The diffraction grating placed in the plane of a roll angular displacement and the interferometer arranged in the plane's orthogonal direction, constitute the measurement pattern for the roll angle with high resolution.

Influence of tilt on collinear calibration of a laser interferometer.

Collinear calibration is a typical and common method for a laser (heterodyne) interferometer, but it usually suffers from the influence of the tilt of the target retroreflectors and the dissymmetry of the optical paths during the calibration. This paper mainly analyzes and models the calibration error caused by the tilt error of the target retroreflectors and reveals the error source that is the disturbance from the rotary error of the guideway slider pair. Experimental results prove the validity of the analysis and model of the calibration error.

Error analysis of a plane mirror interferometer based on geometric optical paths.

Plane mirror interferometer is a common way for the precision displacement measurement. However, during the measurement, it still suffers from disturbances such as misalignments, rotations and air refractive index fluctuations, which lead to poor accuracy. Traditional error analysis is rather limited in the static state and separation of the disturbances.