Experience in using 3 MeV protons for Experience in using 3 MeV protons for PIXE application on environmental and PIXE application on environmental and

biological samplesbiological 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: apantel@nipne.ro

Opportunities for applied research at the new tandem accelerators of IFIN-HH November 1 - 2, 2012, Bucharest-Magurele, ROMANIA

Research Topics experienced by PIXEResearch Topics experienced by PIXE (3 MeV protons) (3 MeV protons)

Environmental pollution studies 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-Bio-Medical studies Medical studies

- Examination of the content levels of some - Examination of the content levels of some micro- and macro-elements found in the found in the tumor tissue of patients having tumor tissue of patients having skin cancer disease, compared with healthy tissue. , compared with healthy tissue.

- Investigation of the - Investigation of the health impact of toxic elements consumed through consumed through foodstuff contaminated by industrial activities. by industrial activities.

Type of samples investigated by PIXEType 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 preparationSample 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.

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.

Certified Reference Materials used for Analytical Quality Certified Reference Materials used for Analytical Quality Control in PIXE analysisControl in PIXE analysis

- 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 X-

ray 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).

Experimental set-upExperimental set-up

Scattering chamber

X-rays

Be window

Al 30 m

X-ray detector

Detector cryostat

Faraday cup

Proton beam

PIXE experimental set-up

9 MV FN Van de Graaff Tandem accelerator of IFIN-HH

X-Ray Detection Efficiency in PIXE experimentsX-Ray Detection Efficiency in PIXE experiments

1 10 10010-4

10-3

10-2

10-1

100

Effi

cien

cy

Energy (keV)

Ge HP Si(Li)

Elements determined by PIXE in environmental and Elements determined by PIXE in environmental and

biological samplesbiological 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

PAC Bucharest Tandem, October 2, 2009

Typical PIXE spectra on environmental and biological samples

10

10

100

1000

10000

100000

1000000

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-1

Dragaiesti (Dambovita county)

PIXE (thin target)E

p = 3 MeV

Without absorberY - internal standard

Potato (pulp)

Se-

K

As-

K

Cr-

K

Sr-

K

Sr-

K

Y-K

Ca-

KK

-K K-K

+

Ca-

K

Y-K

Zn-

K

Br-

K

Zn-

K

Cu-

K

Fe-

K

Fe-

K

V-K

Mn-

K

Nu

mb

er

of

cou

nts

Energy (KeV)

10

1

10

100

1000

10000

100000

1000000

Targoviste(Dambovita county)

Ti-K

PIXE (thin target)E

p = 3 MeV

10 Al absorberY - internal standard

Ni-K

Se-

K

As-

K

Cr-

K

Sr-

KS

r-K

Y-K

Parsley leaves

Ca-

K

K-K

C

a-K

+ K

-K

Y-K

Zn-

K

Br-

K

Zn-

K

Cu-

K

Fe-

K

Fe-

K

V-K

Mn-

K

Num

ber

of c

ount

s

Energy (KeV)

2 4 6 8 10 12 14 16 181

10

100

1000

10000

100000

1000000

Br-

K

Br-

K

sum

pe

ak

(Ca

)

sum

pe

ak

(K, C

a)

Herastrau park

+ s

um

pe

ak

(K, C

a)

7.7

keV7.

3 ke

V

As-

K

Ti-K

Cr-

K

Al-K

P

-K S-K

Cl-K

K-K

Sr-

K

PIXE (thin target)E

p = 3 MeV

no absorberY - internal standard

As-

K

Sr-

K

Y-K

Norway mapleAcer platanoides L.

Ca-

K

Ca-K + K-K

Y-K

Zn-

K

Zn-

K

Cu-

K

Fe-

K

Fe-

K

+ M

n-K

V-K

+ T

i-K

Mn-

K

Nu

mb

er

of c

ou

nts

Energy (keV)

101

10

100

1000

10000

100000

1000000

Ni-K

Sr-

K

Ti-K

PIXE (thin target)E

p = 3 MeV

10 Al absorberY - internal standard

Se-

KAs-

K

Cr-

K

Sr-

K

Y-K

IAEA V-10, Hay

Ca-

KK

-K Ca-

K

+ K

-K

Y-K

Zn-

K

Br-

K

Zn-

K

Cu-

K

Fe-

KF

e-K

+ M

n- K

V-K

Mn-

K

Nu

mb

er

of c

ou

nts

Energy (KeV)

2 4 6 8 10 12 14 16 18 201

10

100

1000

10000

Pb-

L

Sr-

K

Br-

K

Br-

K

+ A

s-K

Evernia prunastri R1EV4

Y-K

Y-K

Pb-

L +

As-

K

Zn-

K

Zn-

K

+ C

u-K

C

u-K

+ N

i-K

Ni-K

F

e-K

F

e-K

+ M

n-K

M

n-K

+ C

r-K

C

r-K

+ V

-K

V-K

+ T

i-K

Ti-K

C

a-K

Ca-

K

K-K

Co

un

ts

nu

mb

er

Energy (keV)

2 4 6 8 10 12 14 16 18 201

10

100

1000

10000 PIXE (thin target)E

p = 3 MeV

Y internal standardAl absorber 10

Tc-

KS

e-K

Se-

K

Br-

KB

r-K

+ A

s-K

IAEA - 350Tuna fish

Y-K

Y-K

As-

K

Zn-

K

Zn-

K

+ C

u-K

Cu-

K

+ N

i-K

Ni-K

Fe-

K

Fe-

K

+ M

n-K

Mn-

K

+ C

r-K

C

r-K

+ V

-K

V-K

Ca-

K

K-K

+

Ca-

K

K-K

Num

ber

of c

ount

s

Energy (keV)

ISAP1, Galati, November 28-29, 2009

2 4 6 8 10 12 14 16 181

10

100

1000

10000

100000 Ca: 22.8±1.2 mg/lMg: 4.44±0.11 mg/lK: 2.31±0.45 mg/lCl: 15.7±0.3 mg/lAl: 266 ± 9 µg/lSr: 139± 19 µg/lFe: 100 ± 5 µg/lZn: 74 ± 3 µg/lMn: 15.1± 0.4 µg/lBr: 12.3 ± 0.6 µg/lNi: 4.7 ± 1.7 µg/lAs: 0.86±0.40 µg/lV: 0.625 ± 0.124 µg/lCr: 0.200± 0.030 µg/l

Br-

K

Ti-K

sum peaks

Cr-

K

Al-K

P

-K

S-K

C

l-K

K-K

Ni-K

Sr-

K

PIXE (thin target)E

p = 3 MeV

no absorberY - internal standard

As-

K Sr-

K

Y-K

Water Bucharest

Ca-

K

Ca-K + K-K

Y-K

Zn-

K

Zn-

K

Cu-

K

Fe-

K

Fe-

K

V-K

Mn-

K

Num

ber of

cou

nts

Energy (keV)

2 4 6 8 10 12 14 16 181

10

100

1000

10000

100000 Ca-K + K-K

sum peaks

Se-

K

Cr-

K

Al-K

P

-K

S-K

C

l-K K

-K

Ni-K

Sr-

K

PIXE (thin target)E

p = 3 MeV

no absorberY - internal standard

Se-

K

As-

K

Sr-

K

Y-K

Water Alunis(Magurele)

Ca-

K

Y-K

Zn-

K

Br-

K

Zn-

K

Cu-

K

Fe-

K

Fe-

KV-K

Mn-

K

Num

ber of

cou

nts

Energy (keV)

ISAP1, Galati, November 28-29, 2009

2 4 6 8 10 12 14 16 18

1

10

100

1000

10000

100000

Br-

K

Ti-K

sum peaks

Cr-

K

Al-K

P

-K

S-K

C

l-K

K-K

Sr-

K

PIXE (thin target)E

p = 3 MeV

no absorberY - internal standard

As-

K

Sr-

K

Y-K

Water V. CalugareascaDarvari

Ca-

K

Ca-K + K-K

Y-K

Zn-

K

Zn-

K

Cu-

K

Fe-

K

Fe-

K

V-K

Mn-

K

Num

ber of

cou

nts

Energy (keV)

2 4 6 8 10 12 14 16 18 201

10

100

1000

10000

100000

Rb

-K

Pb-

L

Pb-

L +

As-

K

Y-K

Y-K

Mo

-K

Cu-

K

Sr-

K

Sr-

K

Br-

K Br-

K

+ A

s-K

Aerosol filterTurnu Magurele

As-

K

Zn-K

Zn-K

Cu

-K

+ N

i-K

Ni-K

Fe

-K

Fe-K

+ M

n-K

M

n-K

+ C

r-K

C

r-K

+ V

-K

V-K

+ T

i-K

Ti-K

C

a-K

Ca

-K

K-K

Cou

nt

num

be

r

Energy (keV)

Mean elemental concentrations for different sample groups of skin samples: I-control group, II-SCC, III-BCC, IV-MM, V-nevus.

I II III IV V10

0

101

102

103

104

P

S

Cl

K

Ca

Ti

Cr

Mn

Fe

Ni

Cu

Zn

Mea

n co

ncen

trat

ion

(ppm

)

Group

ConclusionsConclusions

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 TandetronResearch perspectives at the 3 MV Tandetron of of IFIN-HHIFIN-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.

ReferencesReferences

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) 997-

1008.

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 !Thank you !