Transcript Experience in Using 3 MeV Protons for PIXE Application on

Experience in using 3 MeV protons for
PIXE application on environmental and
biological samples
Ana Pantelica, Constantin Ciortea, Marin Marius Gugiu,
Daniela Fluerasu, Dana Elena Dumitriu,
Dan Gabriel Ghita, Catalin-Ionut Calinescu
Horia Hulubei National Institute for R&D in Physics and Nuclear Engineering
(IFIN-HH), 30 Reactorului St., Magurele, Ilfov county, P.O.B. MG-6,
07712, Romania, e-mail: [email protected]
Opportunities for applied research at the new tandem accelerators of IFIN-HH
November 1 - 2, 2012, Bucharest-Magurele, ROMANIA
Research Topics experienced by PIXE (3 MeV protons)
Environmental pollution studies
- Obtaining of information on pollutant elements (S, V, Cr, Mn, Fe, Ni, Cu, Zn, As,
Se, Br and Pb) in environmental samples, mainly originated by anthropogenic
activities (traffic, ferrous, non-ferrous and phosphorous fertilizer industries).
- To assess the degree of environmental pollution by a comparison with maximum
permissible levels given by the Romanian Regulation bodies
Bio-Medical studies
- Examination of the content levels of some micro- and macro-elements found in the
tumor tissue of patients having skin cancer disease, compared with healthy tissue.
- Investigation of the health impact of toxic elements consumed through foodstuff
contaminated by industrial activities.
Type of samples investigated by PIXE
- tree
leaves of vascular plants, to select plant species capable to
accumulate toxic elements in excessive amounts, being tolerant to
them, in the vicinity of large industrial enterprises and in the adjacent
areas to improve the air quality in urban areas;
- vegetables (different species), grown in the vicinity of industrial
platforms, e.g. phosphorous fertilizer industry, iron and steel industry,
non-ferrous (Pb-Zn) industry;
- lichen biomonitors of bulk (dry and wet) atmospheric deposition;
- water samples (tape water, dwell water, groundwater, surface water).
- airborne particulate matter (PM10) collected on aerosol filters;
- skin samples were collected from cancer patients and controls
- blood serum and urine (thyroidal illness).
Sample preparation
Thin targets for biological samples (~1 mg·cm-2) are prepared by
pipetting on Mylar foil (2.5 µ thickness) volumes of 100-150 µL from a
chemically mineralized plant solution, diluted with deionized water.
Yttrium (Y) is added as internal standard, prepared from a Y2O3 nitric
solution of 160 µg Y·mL-1. The Y concentration on the pipetted target is
about 0.5 %.
The skin samples were freeze-dried before applying the wet chemically
treatment.
Thick targets for soil samples are prepared as pellets.
Certified Reference Materials used for Analytical Quality
Control in PIXE analysis
Calibration and Analytical Quality Control for PIXE technique were performed by
means of standard reference materials of certified element concentrations,
which are chemically prepared as thin target samples (Y internal standard was
considered a beam flux monitor):
- CRM-TMDW (Trace Metals in Drinking Water Standard);
- CRM-OT (Oyster Tissue);
- IAEA-V10 (hay);
- IAEA-393 (green algae);
- IAEA MA-B-3/TM (fish homogenate);
- NBS-1575 (pine needles).
In addition, standards prepared from chemical compounds (thin targets) are
used to assess experimental Kα/Kβ ratios for different elements present in the
samples (e.g. Cl, K, Ca, V, Cr, Mn, Fe, Ni, Cu, Zn.
Experimental set-up
- 3 MeV collimated proton beam (~ 2x2 mm2) at the 9 MV FN Van de Graaff
Tandem accelerator of IFIN-HH
The target is placed at an angle of 450 with respect to the incident beam and Xray detector.
The beam current on the target is about 0.5 - 2 nA.
The transport tubes and the target chamber are maintained at a high vacuum
(10-6 mbar).
- X-ray spectra measurements are performed using electronic spectrometric
chains, with Si(Li) and HPGE detectors working in parallel, and Maestro-32
Ortec acquisition cards mounted in a PC.
- Appropriate absorbers (Al foil) are used to reduce the high peaks of Ca and K
in the vegetal, with the scope of reducing pile-up effects and thus improving the
analytical sensitivity for higher Z elements (e.g. V, Cr, Fe, Ni and Cu).
Scattering chamber
Faraday
cup
Proton beam
X-rays
Be window
Al 30 mm
Detector
cryostat
X-ray detector
PIXE experimental set-up
9 MV FN Van de Graaff Tandem accelerator of IFIN-HH
X-Ray Detection Efficiency in PIXE experiments
0
10
-1
Efficiency
10
-2
10
Ge HP
Si(Li)
-3
10
-4
10
1
10
Energy (keV)
100
Elements determined by PIXE in environmental and
biological samples
Si(Li) Detector
Al, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Pb, Se, Br,
Rb, Sr.
HPGe Detector
K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Pb, Se, Br, Rb, Sr.
PIXE technique with 3 MeV protons is most sensitive for middle-Z elements,
due to the relatively high ionization cross-sections, a lower background
traceable to the bremsstrahlung of secondary electrons, and high detection
efficiency.
Its sensitivity is decreasing both for lower- and higher-Z elements.
For heavy elements, characterized by smaller ionization cross-sections and
lower detection efficiency, PIXE can be completed by NAA.
Mn, Fe, Cu, and Zn detection limits for PIXE and INAA techniques
applied on IAEA-359 (cabbage) sample.
Element
PIXE
INAA
Mn
2.0
0.7
Fe
2.7
9.5
Cu
1.1
7.3
Zn
2.3
0.2
Potato (pulp)
Dragaiesti
(Dambovita county)
PIXE (thin target)
Ep = 3 MeV
Without absorber
Y - internal standard
10
Y-K
10
Energy (KeV)
PAC Bucharest Tandem, October 2, 2009
Sr-K
As-K
Se-K
Br-K
Ca: 400 ± 66 g.kg
-1
K: 20.3 ± 0.5 g.kg
-1
Fe: 19.7 ± 0.6 mg.kg
-1
Zn: 17.2 ± 0.2 mg.kg
-1
Cr: 120 ± 43 µg.kg
Sr-K
Zn-K
-1
100
Zn-K
Cu-K
Y-K
Fe-K
Fe-K
1000
Mn-K
10000
V-K
Cr-K
Number of counts
Ca-K
100000
K-K
1000000
K-K + Ca-K
Typical PIXE spectra on environmental and biological samples
Ca-K + K-K
PIXE (thin target)
Ep = 3 MeV
10 m Al absorber
Y - internal standard
1
10
Energy (KeV)
Sr-K
Sr-K
Y-K
Y-K
10
As-K
Se-K
Br-K
100
Zn-K
Cu-K
Zn-K
Fe-K
Ni-K
Fe-K
Mn-K
V-K
Cr-K
1000
Targoviste
(Dambovita county)
Ti-K
10000
Parsley leaves
Ca-K
Number of counts
100000
K-K
1000000
2
4
6
8
100
10
Energy (keV)
12
14
Br-K
Sr-K
As-K
Y-K
Y-K
Zn-K
Fe-K + sum peak (K, Ca)
7.3 keV sum peak (K, Ca)
7.7 keV sum peak (Ca)
Cu-K
Zn-K
1000
Fe-K + Mn-K
Mn-K
Cr-K
Ca-K
Ti-K
V-K + Ti-K
100000
As-K
Br-K
10000
Al-K
P-K
S-K
Cl-K
K-K
Ca-K + K-K
Sr-K
Number of counts
1000000
Norway maple
Acer platanoides L.
Herastrau park
PIXE (thin target)
Ep = 3 MeV
no absorber
Y - internal standard
10
1
16
18
Energy (KeV)
Zn-K
1
10
Sr-K
Sr-K
Br-K
10
Se-K
Y-K
Ca-K
Y-K
Fe-K + Mn- K
Mn-K
Fe-K
Ni-K
Cu-K
Zn-K
100
Cr-K
10000
As-K
1000
Ca-K + K-K
K-K
100000
V-K
Ti-K
Number of counts
1000000
IAEA V-10, Hay
PIXE (thin target)
Ep = 3 MeV
10 m Al absorber
Y - internal standard
2
4
6
8
10
12
Energy (keV)
Sr-K
Br-K 
Pb-L 
K-K
Y-K 
Y-K
Pb-L + As-K
Ca-K
Fe-K + Mn-K 
Ca-K
Fe-K 
Ni-K
Cu-K + Ni-K 
Zn-K + Cu-K 
Zn-K 
100
Br-K + As-K 
1000
Ti-K
V-K + Ti-K 
Cr-K + V-K 
Mn-K + Cr-K 
Counts number
10000
Evernia prunastri
R1EV4
10
1
14
16
18
20
2
4
6
8
10
12
Energy (keV)
10
Tc-K
Br-K
Se-K
As-K
K-K
K-K  + Ca-K
Y-K
Y-K
Zn-K + Cu-K
Cu-K + Ni-K 
Fe-K
Ni-K
Br-K + As-K
Se-K
100
Zn-K
Ca-K
1000
V-K
Cr-K + V-K
Mn-K + Cr-K 
Fe-K + Mn-K
Number of counts
10000
IAEA - 350
Tuna fish
14
PIXE (thin target)
Ep = 3 MeV
Y internal standard
Al absorber 10m
1
16
18
20
Ca-K
PIXE (thin target)
Ep = 3 MeV
no absorber
Y - internal standard
Y-K
Sr-K
Sr-K
Br-K
As-K
sum peaks
Water Bucharest
Zn-K
Cu-K
Ni-K
Fe-K
Fe-K
Mn-K
Cr-K
Ti-K
V-K
100
Zn-K
K-K
Cl-K
S-K
P-K
1000
Al-K
Number of counts
10000
Ca: 22.8±1.2 mg/l
Mg: 4.44±0.11 mg/l
K: 2.31±0.45 mg/l
Cl: 15.7±0.3 mg/l
Al: 266 ± 9 µg/l
Sr: 139± 19 µg/l
Fe: 100 ± 5 µg/l
Zn: 74 ± 3 µg/l
Mn: 15.1± 0.4 µg/l
Br: 12.3 ± 0.6 µg/l
Ni: 4.7 ± 1.7 µg/l
As: 0.86±0.40 µg/l
V: 0.625 ± 0.124 µg/l
Cr: 0.200± 0.030 µg/l
Y-K
Ca-K + K-K
100000
10
1
2
4
6
8
10
12
Energy (keV)
ISAP1, Galati, November 28-29, 2009
14
16
18
Ca-K + K-K
100000
Water Alunis
Ca-K
(Magurele)
K-K
Y-K
Sr-K
Se-K
Br-K
Se-K
As-K
sum peaks
Sr-K
Y-K
Zn-K
Cu-K
Ni-K
Fe-K
Mn-K
Fe-K
Cr-K
V-K
100
Zn-K
Cl-K
P-K
S-K
1000
no absorber
Y - internal standard
Al-K
Number of counts
10000
PIXE (thin target)
Ep = 3 MeV
10
1
2
4
6
8
10
Energy (keV)
12
14
16
18
Ca-K + K-K
Water V. Calugareasca
Ca-K
PIXE (thin target)
Ep = 3 MeV
Y-K
Y-K
10
Sr-K
Sr-K
Br-K
As-K
sum peaks
Zn-K
100
Zn-K
Cu-K
Fe-K
Cr-K
Mn-K
Fe-K
Ti-K
V-K
Cl-K
S-K
P-K
Darvari
no absorber
Y - internal standard
Al-K
Number of counts
10000
1000
K-K
100000
1
2
4
6
8
10
Energy (keV)
ISAP1, Galati, November 28-29, 2009
12
14
16
18
2
4
6
8
10
12
Energy (keV)
14
10
16
Mo-K
Sr-K 
Sr-K
Br-K + As-K 
Y-K
Zn-K
Cu-K 
Ni-K
Ca-K
Fe-K + Mn-K 
Ca-K
Cu-K + Ni-K 
Fe-K 
Ti-K
V-K + Ti-K 
Cr-K + V-K 
Mn-K + Cr-K 
Zn-K 
Pb-L + As-K 
As-K
100
Pb-L
Rb-K
Br-K 
1000
K-K
10000
Y-K 
Count number
100000
Aerosol filter
Turnu Mag urele
1
18
20
10
4
M ean concentration (ppm )
P
S
10
Cl
3
K
Ca
Ti
10
2
Cr
Mn
Fe
10
Ni
1
Cu
Zn
10
0
I
II
III
IV
V
Group
Mean elemental concentrations for different sample groups of skin samples:
I-control group, II-SCC, III-BCC, IV-MM, V-nevus.
Conclusions
Biological samples, in particular plants with matrix composed from low-Z
elements (H, C, N, O), undetectable by the usual X-ray spectrometers, are very
suitable to trace element analysis by PIXE.
Due to their relatively high K and Ca contents, attention should be paid to the
spectral interferences traceable to escape and summing peaks in the X-ray
spectra.
These difficulties in spectra processing could be successfully resolved by GUPIX
program.
Thin-target PIXE offers the possibility to determine elemental concentrations
without corrections for X-ray self-absorption and proton stopping in target as it is
the case of thick-target PIXE.
As disadvantage, a rather difficult target preparation in some cases, as well as
the risk of incomplete chemical digestion and/or trace element contamination.
Research perspectives at the 3 MV Tandetron of
IFIN-HH
- PIXE and PIGE complementary methods permit to enlarge the range of
elements investigated in environmental and biological samples.
- Elements with atomic numbers lower than 13 can be analyzed with a
good sensitivity by PIGE.
- Elemental concentrations by PIXE are calculated using GUPIX software.
References
1.
PIXE analysis of some vegetable species, A. Pantelica, A. Ene, M. Gugiu, C.
Ciortea, O. Constantinescu, Rom. Rep. Phys., Vol. 63, No. 4 (2011) 9971008.
2.
PIXE analysis of multielemental samples, A. Ene, I.V. Popescu, C. Stihi, A.
Gheboianu, A. Pantelica, C. Petre, Rom. J. Phys. 55, 7-8, 806-814 (2010).
3.
Revitalization of urban ecosystems through vascular plants: preliminary
results from the BSEC-PDF project, Gorelova S. V., Frontasyeva M. V.,
Yurukova L., M. Coşkun, A. Pantelica, C.J. Saitanis, M. Tomašević, M. Aničić,
AGROCHIMICA, 55 (2), 65-84 (2011).
Thank you !