Frank Laboratory of Neutron PhysicsSummer school in Dubna 5.7.-25.7.2010

Prepared by:

B. Andel (SVK), E. Govor (BLR), K. V. Mareš (CZE), M. Mazánová (SVK), A. Moravcsík (SVK), V. Voronova (BLR)

Supervisor : prof. M. V. Frontasyeva, FLNP

The founders of FLNP

IntroductionNeutron Activation Analysis (NAA) is a sensitive

multi-element analytical technique used for both qualitative and quantitative analysis of major, minor, trace and rare elements

NAA was discovered in 1936 by G. Hevesy (Hungary) and H. Levi (Denmark)

Forms of NAADestructive ( radiochemical ) - the resulting radioactive

sample is chemically decomposed, and the elements are chemically separated

Nondestructive ( instrumental ) - the resulting radioactive sample is kept intact

Principle

DetectionIrradiated samples are analyzed by gamma-spectrometry

Neutron sources Isotopic neutron sources (252Cf, 242Am)Neutron generatorsNuclear reactors

At FLNP the pulsed fast

reactor IBR-2 is used

NeutronsThermal 0.025 eV-0.5 eVEpithermal 0.5 eV-100 keVFast 100 keV-25 MeV

Characteristics of INAANon-destructive analysisThe chemical form and physical state of the elements do

not influence the activation and decay processMulti-element analytical techniqueC, H, N, O and Si do not activate wellSuitable even for determination of masses in the order of

10–6–10–9 g and less

Applications of INAA at FLNP

Environmental studies (migration of pollutants in ecosystems, air pollution studies using moss-biomonitors)

Biotechnology for medicine (development of new pharmaceuticals and sorbents)

Material Science (high purity materials, nanoparticles and objects of national heritage)

Dependence of counts on distance between detector and gamma-source

4 5 6 7 8 9 10 11 12 13 14 15 16

3000

4500

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152Eu 121,8keV

cou

nts

in p

eak

(tim

e 7

min

)

distance (cm)4 5 6 7 8 9 10 11 12 13 14 15 16

0

100

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1300

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152Eu 1408keV

coun

ts in

pea

k (t

ime

7 m

in)

distance (cm)

ReferencesP. Bode: Instrumental and organizational aspects of a

neutron activation analysis laboratotyhttp://www.sciner.com/Neutron/naa.htmlhttp://reactor.engr.wisc.edu/naa/http://tin.er.usgs.gov/geochem/doc/inaa.htmhttp://reactor.engr.wisc.edu/naa/UWNRNAA.htmhttp://www.reak.bme.hu/Wigner_Course/

WignerManuals/Budapest/NEUTRON_ACTIVATION_ANALYSIS.htm

http://archaeometry.missouri.edu/naa_overview.html

Fot

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Thank you for your attention