Transcript Zagreb ion microprobe, applications in materials modification and archeometry Iva Bogdanović Radović

Zagreb ion microprobe, applications in materials
modification and archeometry
Iva Bogdanović Radović
Laboratory for ion beam interactions
Ruđer Bošković Institute
Zagreb, Croatia
Workshop on Small-Scale Accelerator Facilities,
Aghios Nikolaos, Crete, Greece, Sept. 7-8,2007
Laboratory for Ion Beam Interactions
Duoplasmatron
1 MV Tandetron
S3
tS1
F1
tM1 tE1
tS1
Sputtering
tQ1 tS2
tM2
M2
tL1
F
S1
6 MV EN Tandem
Q1
D2
3
D1
F2
E2
F1
tM3
tHV
HV
F3
tQ2
E1
M1
S2
Alphatross
M3
External beam
Q3
DM
PIXE
RBS
H.R. PIXE
QM
TOF ERDA
Nuclear
reactions
Nuclear
microprobe
• Negative ion sources
• Direct extraction duoplasmatron (H,D,O) - Tandetron
• Alphatros - RF with charge exchange (H, D, He) – EN Tandem
• Sputtering ion source (H, Li, C, O, Si, Cl, I,...) – EN Tandem, Tandetron (08)
Ruđer Bošković Institute, Zagreb, Croatia
• Beam lines
1.
2.
3.
4.
5.
6.
IAEA beam line - routine PIXE/RBS
TOF ERDA
Nuclear reactions chamber
High res. PIXE, ion implantation
Nuclear microprobe
External beam PIXE
• Microbeam scattering chamber
PIXE
Load lock
xyz &
rotation
STIM
ERDA
Spatial
resolution:
0.5 x 2 m
(low current)
1 x 3 m
(high current)
Microprobe setup for PIXE, RBS, ERDA and NRA
Si particle detector
with mylar stopper
foil
X-ray
detector
Si particle
detectors
IEE
ERDA
• Focusing system upgrades
- Insufficient and asymetric demagnification
(only 11.3 in x)
-ME/q2 product only 7 – mid energy light ions
(e.g. 4 MeV 16O3+)
System
Doublet
Oxford
Triplet
Russian
Quad.
CSIROMARC
Quintuplet
Demagnifi
cation
Dx
-11.3
-30
-16.7
-63
Dy
-67
102
-16.7
82
Spherical
<x|q3>
26.4
4581
110
4934
<y|f3>
137
759
34
161
Figure of
Merit Q
49
20
18
56
Max Poletip field
(T) for 3
MeV p
0.14
0.20
0.11
0.10
Max ME
product *1
7.4
3.6
22
25
Ion microprobe applications
Materials modification
Important processes:
- creation of defects (el. or nucl. stopping)
4.5
- implantation of ions
4.0
Low energy heavier ions
Swift heavy ions
- The highest energy transfer (el. stopping)
- Single ion tracks! (tens of nm)
Proton beam writing
- High aspect ratio
- High resolution beam (Singapore)
- 2D (3D using different ranges)
Energy loss (keV/nm)
- Radiation damage (nuclear stopping)
- Ion implantation
3.5
35Cl
ions
in silicon
3.0
2.5
2.0
1.5
1.0
total
el.
nucl.
0.5
protons in Si
0.0
0.01
0.1
1
10
Energy (MeV)
100
• Why ion microprobe ? – it is ideal radiation source
-X,Y (focusing and scanning)
-Z (ion range - p, , Li, C, O,..)
16
ion
beam
O
12
C
7Li
alphas
quadrupole doublet
focusing lens
object slits
sample
transmitted
ions
Y
IBIC
signal
X
STIM
signal
scan
generator
Y
X
protons
IBIC - charge
collection efficiency
STIM - density
distribution
images
a) Low energy heavier ions
Importance of nuclear stopping
- creates complex (cluster) defects
- maximum at the end of range
- annealing required (for ion implantation)
430 keV protons
6 MeV O ions
Applications to:
1. Structuring electronic defects
2. Creation of nanocrystals (carbon)
Number of vacancies per p 28 !
Number of vacancies per O 2800 !
Ruđer Bošković Institute, Zagreb, Croatia
• Creation of position sensitive radiation sensors
4 MeV 16O
4 MeV 7Li
Si pin diodes are irradiated by different fluences and different ions
Graduated and position dependent radiaton damage is produced
4.063 MeV 7Li+
4 MeV 16O3+
Ruđer Bošković Institute, Zagreb, Croatia
IBIC
measurements
• Ion implantation
ion beam implantation followed by thermal annealing - one of the best techniques
for controlled nanocrystal fabrication
Two different annealing processes:
1. furnace annealing (FA) – T = 1000ºC 1h,
heating speed 600ºC/h
2. rapid thermal annealing (RTA) –
T = 1100ºC 180 s, heating time 90 s, cooling time
100 s
• 3.9 MeV  RBS on SiO2 implanted with 320 keV C
SiO2
D2 = 5 × 1016 at/cm2 D3 = 1 × 1017 at/cm2
H
- IEE ERDA for H detection
- 6.5 MeV 16O2+ dmax (SiO2) ~ 700 nm
- significant difference in H
concentration for RTA and FA samples
- this suggests that H from forming gas
diffuses fast into the sample
- amount of H initially trapped is
decreasing during long FA
b) High energy (swift) heavy ions – ion tracks
The highest existing transfer of energy to
material
- Formation of long ion tracks (tens of
nm diameter)
- Control of hit position by heavy ion
microprobe (as B. Fisher, GSI,
Darmstadt)
- Direct formation of structures, or by
subsequent etching
AFM picture of SrTiO3 surface after exposure of 28
MeV I ions under grazing angle (2°)
Cooperation with University of Duisburg
35 MeV Cl ions on
polycarbonate film
c) Proton beam writing
In p-beam writing, the beam is scanned across a resist material in a predetermined
pattern, which is subsequently developed to produce three-dimensional structures.
- pioneered by the Centre for Ion Beam
Applications (CIBA) at the National
University of Singapore.
- focusing MeV ions to sub-100-nm dimensions
a) Proton beam writing
The penetration depth of the proton beam depends on its energy, and this feature
has been used to produce multilevel structures.
Microsized copy of Stonehenge
fabricated by using p-beam writing in
SU8 resist.
500 keV for fabricating the horizontal
slabs and 2 MeV for exposing the
vertical supports, the complete
structure can be fabricated in one
layer of resist.
F. Watt et al., Materials Today 10 (2007) 20
Application areas: photonics, microfluidic devices, biostructures
Materials: PMMA, SU8, silicon, porous Si (PL), HOPG (ferromagnetic structures)
30-150 nC/mm2 (depending on resist material)
3. Ion microprobe applications
- archeometry (cultural heritage)
proton
beam
quadrupole doublet
focusing lens
object slits
sample
Y
• PIXE (and RBS)
• Sampling is required,
but very small
fragments can be
analyzed!
• Cross sections (paint
layers, alloys, ceramics)
– determination of
elemental distributions
X
scan
generator
Y
x-ray
detector
amplifier
X-ray
energy
spectrum
X
Fe
S
Ca
Pb
elemental
maps
Ruđer Bošković Institute, Zagreb, Croatia
• The case of Apoxiomenos




Found in 1996 near Lošinj in Croatia, 45 m
below sea surface between two rocks
Analyses of state, construction, molding,
organic material in sculpture
X-ray
PIXE, microprobe
Ruđer Bošković Institute, Zagreb, Croatia
• The case of Apoxiomenos
PIXE (or XRF) analysis of surface
was missleading! (12% of Pb)
2 MeV p
Pb-M
Sn-L
Cu
SUS36/16
12% Pb
78%Cu
8% Sn
1.1% Zn
1.5% Ni
microPIXE analysis showed:
- surface enrichment of Pb
- Pb conc. inside ‹ 2% !!
Pb
Cu
Cu was leached by seawater that explain
increased concentration of Pb at the
surface --> Sculpture is of Greek origin
• Analysis of metal threads
Analysis of metal threads of a 17th century church textile using PIXE
The left lamina contains more copper,
whereas the two right ones are silver laminas.
Ruđer Bošković Institute, Zagreb, Croatia
• The case of St. Marko church portal
- Second half of the 14th century – soft sandstone material
- damaged by water and air pollution
900
Ba
Fe
S
800
- microPIXE monitoring of stone
cleaning and conservation
600
500
400
300
Florentine method of cleaning
and consolidation by soaking
the stone in ammonium
carbonate and barium
hydroxide was used.
200
100
0
-4000
-3000
-2000
-1000
0
depth (micron)
Portal sample P1
Ba depth distribution (S1)
1400
1200
1000
total yield
total PIXE yield
700
800
600
400
200
0
-4000
-3500
-3000
-2500
-2000
-1500
-1000
-500
0
500
1000
Ba and S concentration
level variations with depth have
been determined in samples taken
from the portal after the treatment.
depth (micron)
Sandstone sample
treated in laboratory
In addition, Ba depth profiles in
sandstone treated by three
different ways were measured.
• Examples: analysis of pigments
Elemental map
obtained at the RBI
ion microprobe
Analyis of micro-samples
by optical microscopy
methods (at the CCI Lab)
Cromatographic analysis (CCI)
PIXE analysis
(RBI)
The authenticity of art objects
Lead white used since antiquity,
only white used in European
paintings until the 19th century.
- In 19th century lead white (2PbCO3·Pb(OH)2) was replaced by zinc white ZnO
and barium white (BaSO4)
The use of titanium white - maximum age of the painting of about 100 years, as
TiO2 was discovered in 1908.
Meister HGG (Hans Georg Geiger)
- 17th century cultural heritage in Croatia minimal
- Hans Georg Geiger was living and working between 1641 and 1680 in
Slovenia and Croatia (Austrian-Hungarian Monarchy)
- he left 32 paintings (half in Croatia)
2D element
distribution of
- most of his preserved works has not been signed
the pigment
- almost all paintings in churches
cross section
sample taken
from the red
area of the
painting.
S
+Pb +Hg
Sample No1
13th European Conference on X-ray Spectrometry
EXRS-2008 will be held in June 2008, Cavtat, Croatia