Dresden 2017 – wissenschaftliches Programm

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AKBP: Arbeitskreis Beschleunigerphysik

AKBP 6: Poster Session

AKBP 6.15: Poster

Mittwoch, 22. März 2017, 18:30–20:00, P4

A compact and calibrateable von-Hamos X-Ray Spectrometer based on full-cylindrical HAPG mosaic crystals — •Malte Wansleben, Ina Holfelder, Jan Weser, and Burkhard Beckhoff — PTB, Berlin, Germany

The further development of more complex nano-materials and thin film applications with distinct properties needs an analysis independent from any reference material such as X-ray fluorescence analysis (XRF). A reliable quantitative XRF requires calibrated instrumentation.

This work presents a high-resolution wavelength-dispersive spectrometer for XRF in the energy range of 2.3-19.0 keV. By using two full-cylindrical HAPG crystals as dispersive elements in modified von-Hamos geometry a large solid angle of detection and hence high efficiency is realized. This enables shortened measuring times while still having a compact design.

Highly Annealed Pyrolytic Graphite (HAPG) is a synthetic type of carbon which forms mosaic crystals. Although the peak reflectivity is smaller than in perfect crystals, the diffraction profile of this mosaic crystal is much wider leading to an increased integrated reflectivity. A maximum peak reflectivity of more than 60 % was found for the used HAPG films of 40 µ m thickness on a cylindrical Zerodur substrate with a radius of 50 mm.

The calibration of the spectrometer involves detailed characterization of the optics, a precise setup for determining a traceable energy axis, the efficiency and response function of the spectrometer as well as a detailed budget of respective uncertainties.