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Materialien/Werkstoffe Poster: Do., 13:00–15:30 D-P385
30 MeV Photons, Neutrons, Ions and Synchrotron Radiation for Reference
Methods and Materials in Analytical Chemistry
Wolf Görner 1
1 Bundesanstalt für Materialforschung und -prüfung FG I.4 Nuklearanalytik
Unter den Eichen 87 12200 Berlin
It is basic science, which initiates and exploits large size research devices. Nevertheless,
the diffusion of applied research and development into this challenging experimental
field is desirable.
BAM has been using in house instrumental photon activation analysis (IPAA) for
decades aiming at the certification of reference materials (CRMs) such as metals, ceramics,
soils, plastics etc., especially for light elements or halogens. A unique feature
of IPAA is its ability to analyze samples at kg level. This may be necessary for very
inhomogeneous materials e.g. from recycling. Certification is a legal task of the institute.
In the mid-nineties neutron activation (INAA) using the Hahn-Meitner-Reactor as well
as in house ion bombardment broadened the basis of non-destructive chemical analysis
being a valuable counterpart to methods needing chemical separation. Starting in 2002
synchrotron radiation based energy dispersive X-ray spectrometry (SR-EDXRS) was
introduced at the BAMline (BESSY) for the first time into the certification scheme of a
national metrological institute. In the meantime the SR-EDXRS evaluation procedure
has become increasingly reliable. Moreover, the mentioned methods are operated in
combination or for mutual supervision of quality.
Thus, large size research devices have become efficient tools for certification in analytical
chemistry and metrology.
For the time to come there are ideas to further develop the spectrum of variants
available: First, wave length dispersive X-ray spectrometry (SR-WDXRS) will replace
the work intensive reconstitution method at high levels of element contents. Second, an
irradiation facility at the neutron autoradiography site of beam tube NL 1a in the HMI
is worthwhile to be installed. This low cost instrument would enable the analysis of
samples at 100g-level with high representativity and would permit new type investigation
in basic chemical metrology. Third, a highly efficient photon detector array with a
sophisticated coincidence-anticoincidence logic would allow prompt gamma activation
analysis (PGNAA) making the whole periodic system of elements accessible. This high
cost device would be worth operating at accelerators, FRM II and BER II for nuclear
spectrometry and instrumental chemical analysis.