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Rabitsch, Malissa, Hradil, Erlach, Uhlir, Griesser, Hofmann 139
base46. The quantitative amounts of the phases were analyzed by fitting the diffraction pat-
tern using the Rietveld method based on the crystallographic structures within the PANa-
lytical B. V. HighScorePlus program47.
For the analysis a main issue arose due to the minute size of the micro-samples, re-
sulting in a highly-restricted number of crystallites illuminated during the experiment
with X-rays, and the analysis is, therefore, influenced by a reduced orientation distribu-
tion of crystallites. Consequently, the relative intensity distribution within the diffrac-
tion diagram can be changed and the database search of fitted phases can be considerably
hampered. In figure 21 a scanning electron microscope (SEM) picture of a typical sample
from the Vienna Genesis is presented, which was used for the µ-X-ray diffraction (µ-XRD)
phase analysis. The red ellipse indicates the X-ray beam size given by the experimental
method: due to the sample extraction by chipping a miniscule fragment from the ink on
parchment, it is composed from ink/corrosion product combined with tiny parts of the
parchment. This is consistent with the XRF analysis where the bluish marked region shows
mainly the elements Ca, K, Si, Al and O (parchment) whereas the greenish marked area
displays the main elements Ag and Cl (ink area).
In the best case, the standard phase analysis by X-ray diffraction methods uses samples
typically in the mm2 range with randomly distributed crystallites. This guarantees a statis-
tically balanced orientation distribution of the crystallites present, resulting in an optimal
quality of the diffraction pattern, allowing direct comparison with the theoretical diffrac-
tion patterns within the database.
Typical diffraction patterns are presented in Fig. 22 (sample T1 from folio 4, page 8)
and Fig. 23 (sample T9 from folio 18, page 35) taken of the manuscript. Table 1 presents the
results for the crystalline phase analysis on the Vienna Genesis samples.
46 Soorya et al., 2002, pp. 333–337.
47 Degen et al., 2014, pp. 13–18.
Open-Access-Publikation im Sinne der CC-Lizenz BY 4.0
The Vienna Genesis
Material analysis and conservation of a Late Antique illuminated manuscript on purple parchment
- Title
- The Vienna Genesis
- Subtitle
- Material analysis and conservation of a Late Antique illuminated manuscript on purple parchment
- Editor
- Christa Hofmann
- Publisher
- Böhlau Verlag
- Location
- Wien
- Date
- 2020
- Language
- English
- License
- CC BY 4.0
- ISBN
- 978-3-205-21058-0
- Size
- 17.3 x 24.5 cm
- Pages
- 348