X-RAY Capillary Optics

• Continuous optimisation thanks to decades of experience
• Development and production in Berlin
• Compared to a conventional pinhole collimator: amplification of the XRF density by up to 10,000-fold
• Shortening of measurement time by concentrating the excitation beam on a small spot at very high intensity
• Small spot sizes of up to < 10*  µm for measurements on smallest components and microstructures
• Spectral bandwidth from 1 keV - 50keV
• Different types available: Monocapillaries with cylindrical, elliptical, or parabolic shape, and a variety of polycapillaries incl. halo-free versions
• In-house developed software WinFTM supports mapping functions, special evaluations like array mode and automated measurements

* Spot size at Mo-K

Measurement of thin and very thin coatings and analysis of complex multilayer systems:

• Coatings on silicon wafers and PCBs
• Measurement of Ag content in solder bumps
• SMD components
• Plug-in contacts
• Leadframes
• Microscale element and layer thickness mappings

The development and manufacture of high-precision capillary optics for X-ray beam shaping is one of our core technological competences. Thanks to these components, Helmut Fischer's XRF instruments are able to measure on the smallest components and microstructures. As one of only 2 manufacturers worldwide, we ensure innovation and the highest measurement precision.

In addition to the use of highly brilliant microfocus sources and efficient energy-dispersive detectors, the application of polycapillary optics is also decisive for the optimal measurement performance of an XRF spectrometer. A polycapillary lens concentrates the excitation beam on a small spot at very high intensity, which leads to a significant reduction of the measurement time. Modern developments in the field of nanotechnology and microelectronics are increasing the demand for ever better spatial resolution. For a long time, the spatial resolution in the high-energy range of the X-ray beam was clouded by the so-called halo effect. This effect led to a significant deterioration of the lateral resolution of the measuring spot on the sample surface and thus caused erroneous compositional determinations in quantitative material analysis. Thanks to our many years of experience and effective development work, we were not only able to reduce the halo effect, but also to produce polycapillary lenses that are halo-free.

At Helmut Fischer you benefit from almost 30 years of know-how in the development of optimised polycapillaries for a wide range of applications. The optics are based on the effect of total external reflection on the inner smooth surface of glass capillaries. The critical angle of the total reflection depends on the energy of the X-ray beam, the density of the reflecting material and the roughness of the reflecting surface. Since glass has a very low roughness, it is an efficient material for manufacturing X-ray capillary optics. Capillary optics differ in terms of the number of reflections on the inner surface of the capillary. We have specific designs in the Fischer portfolio: Monocapillaries with cylindrical, elliptical or parabolic shape as well as a variety of polycapillaries. An overview of the various X-ray analytical methods in which the capillary optics are used is given in the table:

Elliptical or parabolic-shaped monocapillaries are imaging optical elements with unique total reflection. The size of the focal point of an elliptically shaped capillary is determined by both the size and shape of the source and the manufacturing accuracy of the capillary. Parabolically shaped capillaries focus a parallel beam to a focal point or parallelise the divergent beam of a point source. A synchrotron beam is focused by them on a very small point up to 250 nm.