Workshop PET/SPECT/RADIO-ISOTOPES in Greece

Workshop PET/SPECT/RADIO-ISOTOPES in Greece

26 June 2006

The XRF method: Development and

Applications

Ch. Zarkadas and A.G. Karydas

N.C.S.R. “Demokritos”, Institute of Nuclear Physics,

Aghia Paraskevi, 15310, Athens Greece


26 June 2006

Outline

The X-ray Fluorescence technique

XRF facilities at the I.N.P of “Demokritos”

Conclusions

Applications

State of the art instrumentation

Κ L M

Nucleus

E0

Ka

Electrons


26 June 2006

Physics of the XRF technique

A typical ΧRF setup

Detector

Preamp

Amp

ADC MCA

Computer

Source

Sample

Substrate

X-rays

Αρι

θμός

γεγ

ονότ

ων

Ενέργεια (keV)


26 June 2006


26 June 2006

State of the art instrumentation

Rotating anode (18kW)

X-ray Tubes

High power (3kW)

Low power (50W)

X-ray DetectorsLN cooled

Si(Li)

Thermoelectrically cooledSDD, Si-PIN

Digital Electronics

X-ray OpticsPolycapillary

lenses

HOPG crystals

Provide/Enable:•Intense exciting X-ray beams

•Energy resolution down to 135 eV

•High count rate handling capabilities (106 cps!!!!)

•Low Z detection (B,C,O,N)

•Formation of focused intense beams – microbeams (10μm-100μm)

•In depth analysis combining two polycapillaries (3D confocal XRF)


26 June 2006

XRF instruments at the I.N.P STXRF (Secondary Target XRF)

Detector guide

Sample

Filters

Crystal

Secondary target Be window

Shutter

Provides:•Selectable almost monochromatic excitation

•Polarized doubly scattered continuum


26 June 2006

XRF instruments at the I.N.P TXRF (Total Reflection XRF)

0 2 4 6 8 10 12 14 16 18 200,0

5,0x102

1,0x103

1,5x103

2,0x103

2,5x103

Μο(

Κα)

Y(Κ

α)Sr

(Κα)

Se(Κ

α)

Zn(

Κα)

Ni(

Κα)

Ti(

Κα)

Cr(

Κα)

Ca(

Κα)

Si(Κ

α)

Αρι

θμός

γεγ

ονότ

ων

Energy (keV)10 20 30 4010

0

101

102

103

Μο(Kβ)

Μο(Kα)

Σκεδαζόμενη ακτινοβολίαAr(Kα)

Αρι

θμός

γεγ

ονότ

ων

Ενέργεια (keV)


26 June 2006

The demokritos portable milli beam XRF spectrometer

Features:

•Rh, side window, 50W, air cooled tube, 75μm Be window

•PIN diode detector, FWHM = 165 eV MnKα, 500 μm thickness

•Electromagnetic beam shutter

•Rotatable filter wheel

•Lasers for sample positioning

•Collimating parts, Beam spot

~ 3mm at sample position

•Control unit


26 June 2006

Handheld XRF spectrometer (under design)


26 June 2006

The demokritos μXRF spectrometer

10mm2 SDD

30W, Rh anode μfocus (50μm x 50μm) X-ray

tube

Camera

Polycapillary lens

X-Y-Z stage 10μm steps

Polycapillary lens 41MLS03Focal spot 60-80 μmOptimized for higher energiesOutput focal distance 21.2 mmMinimum Halo effectHe filled


26 June 2006

Biomedical Applications (I) Determination of Trace Elements in Human

Blood serum

2 4 6 8 10 12 14 16 18101

102

103

104

105

106

Ar ξ=38.3 mg/cm2

V=40 kVi=20 mAt=6000 sec

Br

Se

Ga*

ZnCuFe

CaK

Cl

S

Scattered peaksC

oun

ts

Energy (keV)

Y Secondary Target Excitation

MDL’s: 12 ppb

Yttrium secondary target excitation


26 June 2006

8 9 10 11 120

200

400

600

Pt-L Pt-L

Br-KZn-K

Se-K

Cu-KZn-K

Cou

nts

Energy (keV)

3 hrs 600 s 10 s

Biomedical Applications (II) Determination of cis-Pt in mice Blood

Yttrium secondary target excitation


26 June 2006

Biomedical Applications (III) Determination of Uranium in urine

10 11 12 13 14 150

1x103

2x103

3x103

Cou

nts

Br

Se

U

Br

Se

Pb

Energy (keV)

10 11 12 13 14 150

2x103

4x103

6x103

MDL’s: 250 ppt

Total reflection + chemical treatment

5 ppb U


26 June 2006

2 4 6 8 10 12 14 16 18 20101

102

103

104

105

V=50 kVi=30 mAt=1000 sec

S

Ar

Br

Sr

Ga*

Ca

K

Cl

Si Scattered peaks

Cou

nts

Εnergy(keV)

Environmental Applications (I) Determination of Trace Elements in

potable water

Bottled water

Tap water

Total reflection, direct measurement

MDL’s: 6 ppb


26 June 2006

Environmental Applications (II) Determination of Trace Elements in

airborne particulates The case of “Sahara rain”

Mo secondary target excitation

2 4 6 8 10 12 14

200

400

600

800

1000

1200

1400

1600

1800

2000

Sr-K

Rb-K

Pb-L

Pb-L

Ga-K

Zn-K

Cu-K

Ni-K

Fe-K

Mn-K

Cr-K

Ti-K

Ca-K

K-K

Co

un

tsEnergy (keV)

Net Spectrum


26 June 2006

Cultural Heritage Applications (I) Determination of pigments on

marble statues

Egyptian Blue

Ochre

Organic

Jarosite

Orpiment

Ochre

Ochre

Ochre

Ochre

Sulfur Flower

Sulfur

Organic Black

Orpiment

Celadonite

Celadonite

Orpiment (As2S3)

Egyptian Blue (CuCaSi4O10)

0.0 0.1 0.2 0.3 0.4 0.5

5000

10000

15000

20000

25000

30000

Cou

nts

(a.u

.)

Depth (mm)

Hg Fe Ca

Linear scan in a paint layer section

10-15 μm cinnabar20-30 μm red ochre


26 June 2006

10-15 μm Egyptian Blue100-140 μm Black30-50 μm Kaolinite10-20 μm Cinnabar

0.0 0.1 0.2 0.3 0.4 0.5 0.6

0

5000

10000

15000

20000

25000

30000

35000

Cou

nts

(a.u

.)

Depth (mm)

Cu Ca Fe Hg

Linear scan in a paint layer section


26 June 2006

34 gold jewels

Benaki Museum-10 0 10 20 30 40 50

40

50

60

70

80

90

100

110

Au+Ag=100%

Au+Ag=97%

Orientalizing [3] Archaic [5] Classic [3] Hellenistic [18] Roman [5]

A

BBenaki Museum gold jewels

7th-2nd Cent. B.C.

Au

(%)

Ag (%)


26 June 2006

Cultural Heritage Applications (II) Chemical discrimination of gold

alloys

Rh direct excitation

0 5 10 15 20 25 30100

101

102

103

104

105

Sn-K

Rh-

K

Pb-L

Pile

Up

Pb-L

Cu-

K

Zn-

K

Ni-

K

Cu-

K

Fe-K

Sn-L

Cou

nts

Energy

BCR D Sn 10% Pb 10% Measuring time: 5 sec

μXRF spectrum of a tin-lead Copper alloy


26 June 2006

Summary - Conclusions - Perspectives


26 June 2006

X-ray Fluorescence is nowadays a dynamic and well established technique for quantitative and/or qualitative analysis (non destructive if necessary)

A new generation of XRF spectrometers is currently available at Demokritos

In depth analysis has been already achieved (3D confocal setups) and will be the trend in the near future

Offers multielemental and sensitive analysis in a wide variety of different samples in the interdisciplinary field

Documents

Workshop PET/SPECT/RADIO-ISOTOPES in Greece