2'6' PIXE Analysis of Metals, Paper and other Artifacts

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2.6. PIXE Analysis of Metals, Paper and other
Artifacts
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The surface of Karomama
Karomama, daughter of the Theban Priest Nimlot
of the southern empire. She married Takelat II
of the north cementing the union of the southern
and northern Egyptian empire.
Among the Egyptian antiquities was a statuette of
Queen Karomama, of the twenty-second dynasty. It
was thickly covered with green rust. The
conservators suspected it was no ordinary example
of bronze and it was resolved to carefully remove
the coating. As the operation went on the
character of the metal changed. Finally it was
discovered that the bronze was damascened with
gold and silver, and that much ornamentation was
spent over the royal robes. (Arthur Lee 1890)
(report on original analysis of surface
corrosion.)
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The microstructure of surface layers
Two faces of Egyptian egida ca 500 BC, (Louvre,
Paris)
Depth profiling of surface with high energy
proton PIXE techniques to obtain, composition,
structure and corrosion properties ?
identification of original surface below material
and corrosion build-up.
Sacred Amon worshipper Karomama, ca 820 BC -
22nd dynasty, (Louvre, Paris)
Bronze statuette, inlaid with gold, silver,
black a white paste (eyes)
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Surface Deterioration of Bronze

• PIXE scan 50x150µm2
• 0.37 chlorine concentration
• 15µm into corrosion layer
• 0.12 chlorine concentration
• gt50µm depth

Cu
Pb
Sn
Ni
Corrosion ? Copper chlorid
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Metal Soldering
Myrtle wreath, gold, Greek/Macedonian 4th
century BC
Analysis of soldering technique for conservation
reconstruction
J. Maish, JAIC 34 (1995) 113-127
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The Achaemenid Pendant
The Achaemenid ????????? empire was founded by
Cyrus the Great in 559 BC
Excavated from Iranian tomb motif represents
deity with two birds flying in front. 28 old
balls soldered to tubes bent from thin old sheets
and soldered together.
4th century BC
G. Dermortier, Bucl. Instr. Method. B 14 (1986)
152 - 155
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PIXE view of the Achemenide pendant
Relief work with fairly constant Au and A
content Fe shows at joints and solder points,
tube shows high Cu concentration
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PIXE analysis of solder joints
B
A
D
C

• Solder connections clearly recognizable
  composition of each
• solder alloy reveals ancient soldering technique
  
• Brazing with Cu-Ag-Cu alloy at point A,B
  happened at T?800oC with slow
• cooling.
• At C joint by local fusion of elements at
  T?1000oC, reduction of less noble
• elements
• at D copper diffusion bonding at T?900oC, Cu
  diffuses into Au at TltAu
• melting point providing very hard bond.

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Cadmium Forgery
The Vespasian necklace,
Cadmium in ancient metalwork indicates forgery!
supposedly from the 1st century AD. The three
center medallions show images of Vespasian,
Titus, Domitian.
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Detailed Analysis of medallion
Systematic micro-beam analysis
Reveals Cd enrichment at solder points
G. Dermortier T. Hackens, Nucl. Instr. Meth.
197 (1982) 223-226
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Experimental Arrangement
Mapping out silver-copper solder material
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Micro-beam analysis of Cu-Ag-Au solder
However, Cd can be in ore material. Modern
solders show anti-correlation between Cadmium and
Copper. This solder shows correlation between Cd
and Cu which indicates ancient origin!
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Authenticy check for ship wreck coins
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Nuestra Senora de Atocha
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Treasures from the Atocha
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Doubts about the authenticy of some of the
Atocha Escudos on the market
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Analysis of Spanish Escudos
Suspect coin has considerably higher Au content
and less Ag content than Spanish Escudo
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Nature of ink and pigments with PIXE
PIXE has developed into a major analytical
tool (like X-ray fluorescence) to investigate ink
and pigments in old manuscripts and parchments.

• The main goal is to understand ancient production
• processes and the associated chemical techniques.
• Further goals are
• to identify authors and artists of ancient
  paintings
• to detect and identify forgeries.

gallic acid FeSO4.7H2O water iron-gall ink
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Nature of ink and pigments with PIXE

• Ritualistic talmudic texts had to be written with
  special ink. During the 12th and 13th century a
  bitter dispute between talmudic scholars about
  the question which kind of ink does really
  fulfill the ritualistic requirements
• indian ink used by French Jews
• gall ink used by German Jews
• A decision was made not to accept iron- but only
  copper vitriol since the last 6th century entry
  into the Talmud (summary of ancient Rabbi
  decisions) mentioned gall-apples copper vitriol.

PIXE analysis of parchment shows strong iron
content, in disobedience of the decision!
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Trionfo dAmore Botticelli Drawing
The drawing is attributed to Botticelli the
author of the incipit is unknown!
Pigment analysis with PIXE to determine the
technique and origin of paint.
Petrach manuscript, Biblioteca Classense Ravenna,
Fiesole
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PIXE analysis of Trionfo damore
Book holder construction to focus beam onto the
series of pre-selected points in the drawing.
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Paint analysis

• The results showed that ochres
• with addition of a lead base
• pigment, were used to obtain
• the brown colour.
• Iron-gall ink was used to trace
• the drawing.
• Lead point was used in the
• preparation of the drawing.
• It was not possible to identify
• the Lilac pigment used.
• The blue colour of the sky is a
• lead based pigment deposited
• on top of an underlying mixture
• of blue pigments.

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Ink and paper of the Gutenberg bible
Deep black ink after 500 years
Analysis of many single letters showed that ink
had unusually high copper (Cu), nickel (Ni), and
lead (Pb) concentration ? high printing quality!
R. Eldred et al., Nucl. Instr. Meth. B3 (1984)
579-583
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Letter identification through PIXE
Use of the lateral resolution of a microprobe
permits the study of small details in the
material. For example PIXE analysis of paper
content combined with statistical methods leads
to the identification of faint letters.
photograph
Greek handwriting of letter ? on papyrus
PIXE image
G. Löwestamm E. Swietlicki, Nucl. Instr. Meth.
B43 (1989) 104
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Comparative dating
Galileo dated his writings only infrequently,
PIXE analysis of ink May provide clues toward
development of thought and ideas. Un-dated
manuscript can be Placed in time and context
by PIXE analysis of ink.
Hand-made ink showed differences from batch to
batch
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Summary PIXE
PIXE is very similar to XRF, the mechanism for
exciting the atoms to generate the characteristic
X-rays is not based on X-ray irradiation of the
sample but on the bombardment with high energy
particles typically protons up to 10 MeV. The
disadvantage to XRF is, that only small areas can
be studied to small depths. For a global study
(cm2 areas) of the chemical characteristic of a
sample XRF is the better method. For the study of
mm2 to mm2 areas PIXE is the superior approach.
Its large advantage to XRF is that two or three
dimensional images of the elemental distribution
In the sample can be produced with high spatial
resolution. Depth profiling is possible within a
fairly limited depth range of 0.1mm only. Like in
XRF studies the K-and L-transitions of the low to
high Z elements are the main signatures.