The analytical techniques most widespread for certification in the iron and steel industry are X-ray Fluorescence Spectrometry (XRF), Arc/Spark Optical Emission Spectrometry (OES), and Glow Discharge

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• The analytical techniques most widespread for
  certification in the iron and steel industry are
  X-ray Fluorescence Spectrometry (XRF), Arc/Spark
  Optical Emission Spectrometry (OES), and Glow
  Discharge OE Spectrometry (GDS-OES), which are
  all Atomic Emission Spectroscopy (AES) techniques
  relying on the analysis of radiation emitted by
  atoms from the surface layers of the investigated
  material.
• By contrast, nuclear INAA investigates the whole
  sample as its entire volume is irradiated in the
  thermal neutron field of a nuclear reactor
  without any physico-chemical or microstructure
  alteration. For this reason, and given the
  performance of INAA, we assumed its application
  could improve the information on elemental
  composition usually obtained by AES techniques,
  especially in the case of minor and trace
  elements.
• ..
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• International Workshop IWIRAD 2005
  
  
  Bucharest, 20-21 June, 2005

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• Objective
• Checking the above assumption by comparing
  results obtained within the frame of an
  international Proficiency Tests (PT) exercise by
  19 laboratories (18 of which employed AES
  techniques, and only the 19th one employed the
  INAA technique) with results obtained by a
  network composed of 5 INAA Laboratories on
  samples from the same material - a special high
  alloy steel (SS1) produced by the Swedish
  Institute for Metals Research (SIMR).
• The PT exercise, launched and organized by
  SIMR/ KIMAB envisaged an accurate
  characterization of the material composition in
  order to obtain a Certified Reference Material.
• .
• Later, SIMR changed its title as follows the
  Swedish Institute for Corrosion Metals
  Research (KIMAB)
• ....
  
• International Workshop IWIRAD 2005
  
  Bucharest, 20-21 June,
  2005

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• The ACTIVA-N laboratory (IFIN-HH, Romania),
  which joined the KIMAB PT exercise in 2004,
  developed in 2005 a Network collaboration with
• four other INAA laboratories, namely, with
  
• - Belgium (with the Belgian Nuclear Research
  Centre, Mol),
• - Hungary (with INT, Budapest),
• - Poland (with INCT, Warsaw),
• - Romania (with INR, Pitesti),
• aiming at checking within the frame of an
  Inter-Laboratory Comparison (ILC) exercise the
  INAA performance on the same material
• reproducibility, influence of the various
  standardization methods, consensus of results
  obtained by the same technique in different
  laboratories,
• and the usefulness of the network for
  analyzing and certifying stainless steels.
• The SS1 used for INAA experiments
  consisted of chips of 2-3 mm each.
• ..
  ...
• International Workshop IWIRAD 2005
  
  Bucharest, 20-21 June,
  2005

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• Experimental and evaluation conditions
• The SS1 samples were irradiated in the nuclear
  reactor of each participant laboratory in a
  thermal neutron flux of (1012-1013) n?cm-2?s-1
  and then analyzed by ?-ray spectrometric
  equipments using high resolution HPGe
  detectors.
• The measurements, mainly based on
  measurements of the delayed ?-rays emitted by the
  activated nuclei, evidenced 11 elements (Cr, Mn,
  Fe, Ni, Co, Cu, As, Sb, Mo, V, W) in the
  irradiated samples.
• The element concentrations were determined by
  each laboratory using its own standardization
  procedure
• a relative procedure based on CRMs materials
  (ACTIVA-N Lab. Romania, Hungary),
• - a complex procedure involving chemical
  treatment (Poland),
• - an in-house developed standardization
  method similar to the k0,Au one,
• but using Zr instead of Au (INR Romania),
  
• - the Laboratory from Belgium used INAA
  based on single element
• solution standards traceable to NIST, and a
  SMELS sample to check
• and validate the experimental protocols.
• ...
• the elemental standards and spectral purity
  elements or oxides were dissolved in aqua regia
  or nitric acid of high purity, and then air-dried
  in a laminar flow box for obtaining solid
  standards
• ..
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• International Workshop IWIRAD 2005
  
  Bucharest, 20-21
  June, 2005

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• Evaluation and Conclusions
• The comparative performance of the nuclear and
  Atomic Emission Spectroscopy techniques was
  evaluated using the z-score criterion1-3 ,
  calculated for the mean concentration values of
  each element the AES data were taken from the
  preliminary data presented in the KIMAB Report4
  issued in June 2005.
• The results proved a new evidence of the INAA
  performance established within the INAA network,
  as the standard deviation values corresponding to
  the mean concentration of each of the 11 elements
  were reduced, irrespective of the fact that they
  were obtained in different irradiation /
  measurement conditions and using various
  Standardization methods and impose a more deep
  and detailed study in continuation.
• In the following, we present - comparatively -
  the preliminary results obtained within the frame
  of the INAA - ILC exercise and the preliminary
  results obtained by the KIMAB Institute from the
  international PT exercise they had launched in
  2004, directly taken from their Report.
• ....
  .
• International Workshop IWIRAD 2005
  
  Bucharest, 20-21
  June, 2005

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