Neutron Activation Laboratory

The 2 MW JEEP II reactors at IFE provides excellent facilities for Neutron Activation Analysis (NAA).

IFE is the only institute in Norway utilising such a facility. JEEP II has a maximum thermal neutron flux of 1.3 x 1013 cm -2 s-1

The reactor provides:

  • moderate ambient temperature in the irradiation channels avoids thermal degradation of organic samples
  • high thermal to epithermal ratio at specific positions reducing side reactions
  • easy and dry sample handling
  • vacuum operated rabbit system for short irradiation times
  • possibilities for long term irradations


In Instrumental Neutron Activation Analysis (INAA) samples are irradiated together with standard materials of known elemental composition. After some appropriate decay period, high resolution gamma ray spectrometry is used to measure the intensity and energies of the emitted gamma radiation. A comparison between activities induced in standards and samples provides the basis for calculation of elemental abundances.

JeepII-reaktor

Picture showing the Jeep-II reactor at Kjeller, Norway

If chemical separations are performed on samples after irradiation the technique is called Radiochemical Neutron Activation Analysis (RNAA). By this approach interfering radionuclides are removed and the radioisotope of interest may be concentrated, thus improving sensibility and lowering detection limits.

The main advantages of NAA are:

  • the possibility of multi-element analysis
  • excellent detection limits for many elements
  • the possibility of non-destructive analysis; no time consuming dissolution processes, low contamination risk and no loss of sample material
  • determination of total concentrations in heterogeneous samples
  • in RNAA the chemical separations are performed after irridiation minimising possible contamination problems.


Som application. Geological material.

  • determination of rare earth elements (Sc, La, Ce, Nd, Sm, Eu, Tb, Yb, Lu), Hf, Ta, Th, U and other trace elements without sample dissolution
  • exploration purposes (especially for gold)
  • determination of trace elements in silicates, bitumens and coals without sample dissolution


Environmental and biological samples

  • determination of total concentrations of halogens (Cl, Br, I) in organic solutions (e. g. EPOC1/ EOC1)
  • determination of total concentrations of Hg, Se and As in sediment samples and biological tissues such as liver and muscular tissue
  • multi-element analysis of aerosols on filters


Archaeology

  • the non-destructive version of NAA permit analysis of archaeological specimens (pottery, coins, etc.) for characterisation, providing useful information about sources and trade routes, without destroying the specimen
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