**3. Applications**

**2.6. Detection limits of NAA**

interference.

The detection limit represents the ability of a given NAA procedure to determine the minimum amounts of an element reliably. The detection limit depends on the irradiation, the decay and the counting conditions. It also depends on the interference situation including such things as the ambient background, the Compton continuum from higher energy-rays, as well as any-ray spectrum interferences from such factors as the blank from pre-irradiation treatment and from

166 Imaging and Radioanalytical Techniques in Interdisciplinary Research - Fundamentals and Cutting Edge Applications

where: DL is the detection limit and B is the background under a gamma-ray peak. This re‐ lation is valid only when the gamma-ray background (counting statistical error) is the major

**1.** The amount of material to be irradiated and to be counted. This is often set by availabil‐ ity, sample encapsulation aspects and safety limits both related to irradiation (irradia‐ tion containers) and counting (e.g. with Ge well-type detectors), and possibly because of neutron self-shielding and gamma-ray self-absorption effects. For these reasons prac‐

**3.** The duration of the irradiation time. This is set by practical aspects, such as the limita‐ tions in total irradiation dose of the plastic containers because of radiation damage. The maximum irradiation time for polyethylene capsules is usually limited to several hours,

**4.** The total induced radioactivity that can be measured is set by the state-of-the-art of counting and signal processing equipment, with additional radiation dose and shield‐ ing considerations. As an example, the maximum activity at the moment of counting

**5.** The duration of the counting time. A very long counting time may set limits to the num‐ ber of samples processed simultaneously in case the radioactivity decays considerably

**6.** The total turn-around time. Although sometimes better detection limits may be ob‐ tained at long decay times, the demands regarding the turn-around time often imply that a compromise has to be found between the longest permissible decay time and cus‐

**7.** The detector size, counting geometry and background shielding. The detector's charac‐

It all illustrates that the detection limit for a given element by INAA may be different for each individual type of material, and analysis conditions. In Table 5 are given, as an indica‐

during this counting time. Moreover, it reduces sample throughput.

teristics may be set in advance by availability but several options exist.

*DL* = + 2.71 4.65 , *B* (26)

packing materials. The detection limit is often calculated using Currie's formula:

However, practically, the INAA detection limits depend on:

for instance 5 hours at 5 × 1017 m-2s-1.

tomer satisfaction.

may have to be limited to approximately 250 kBq.

tically the sample mass is often limited to approximately 250 mg.

**2.** The neutron fluxes. These are clearly set by the available irradiation facilities.

It is hardly possible to provide a complete survey of current NAA applications; however, some trends can be identified [27]. At specialized institutions, NAA is widely used for anal‐ ysis of samples within environmental specimen banking programmes [28]. The extensive use of NAA in environmental control and monitoring can be demonstrated by the large number of papers presented at two symposia organized by the IAEA in these fields: "Appli‐ cations of Isotopes and Radiation in Conservation of the Environment" in 1992 [29] and "Harmonization of Health-Related Environmental Measurements Using Nuclear and Isotop‐ ic Techniques" in 1996 [30]. Similar trends can also be identified from the topics discussed at the regular conference on "Modern Trends in Activation Analysis (MTAA)" and at the sym‐ posia on "Nuclear Analytical Methods in the Life Sciences" [31-33]. Additional sources of re‐ cent information on utilizing NAA in selected fields, such as air pollution and environmental analysis, food, forensic science, geological and inorganic materials as well as water analysis can be found in the bi-annual reviews in Analytical Chemistry, for instance cf. Refs [34-42]. It follows from these reviews that NAA has been applied for determining many elements, usually trace elements, in the following fields and sample types:

**Element Unity Black seeds Fenugeek Caraway** Sm mg/Kg 0,092 ± 0,004 0,18 ± 0,01 0,142 ± 0,005 Sr mg/Kg 203,2 ± 7,8 136,88 ± 7,4 101,7 ± 4,7 Th mg/Kg 0,159 ± 0,009 0,32 ± 0,02 0,195 ± 0,014 Zn mg/Kg 68,06 ± 2,11 42,8 ± 1,4 40,24 ± 1,30

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**Table 6.** Elemental concentrations in the medicinal seed samples (Black seeds, Fenugreek, Caraway).

**Figure 11.** Concentration of the major and minor (a) and trace (b) elements in the medicinal seed samples.

**3.** Environmental: in this domain, related fields concerned by NAA are: aerosols, atmos‐ pheric particulates (size fractionated), dust, fossil fuels and their ashes, flue gas, ani‐ mals, birds, insects, fish, aquatic and marine biota, seaweed, algae, lichens, mosses, plants, trees (leaves, needles, tree bark), household and municipal waste, rain and hori‐ zontal precipitations (fog, icing, hoarfrost), soils, sediments and their leachates, sewage

sludges, tobacco and tobacco smoke, surface and ground waters, volcanic gases.

SRM IAEA-140/TM was executed.

Recently, our laboratory is strongly involved in various areas of application of k0-NAA. The present work focuses on the application of the k0-NAA method in Nutritional and Health-Related Environmental field [44]. Tobacco holds a leading position among differ‐ ent commodities of human consumption. The adverse health effects of toxic and trace el‐ ements in tobacco smoke on smokers and non-smokers are a special concern. In the present study, the concentration of 24 trace elements in cigarette tobacco of five different brands of Algerian and American cigarettes have been determined by k0-based INAA method. The results were compared with those obtained for samples from Iranian, Turk‐ ish, Brazilian and Mexican cigarettes tobacco. To evaluate the accurate of the results the

A multi-element analysis procedure based on the k0-NAA method was developed at Es-Salam research reactor allowing to simultaneously determine concentrations for 24 ele‐ ments (As, Ba, Br, Ca, Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Na, Rb, Sb, Sc, Se, Sm, Sr, Ta,


In this work, we have used the INAA technique to analyse the traditional medicinal seeds prescribed for specific treatment purposes, were purchased from local markets [43]. The samples were irradiated at Es-Salam research reactor, at a power of 5 MW for 6 h. The accu‐ racy of the method was established by analyzing reference materials. Twenty elements were measured, with good accuracy and reproducibility (Table 61 ). The concentration of elements determined, was found to vary depending on the seeds (Fig.11). The daily intake of essential and toxic elements was determined, and compared with the recommended values. The probable cumulative intake of toxic elements is well below the tolerance limits.


1 nd : not detected.


**Table 6.** Elemental concentrations in the medicinal seed samples (Black seeds, Fenugreek, Caraway).

cf. Refs [34-42]. It follows from these reviews that NAA has been applied for determining

**1.** Archaeology: samples and objects such as amber, bone, ceramics, coins, glasses, jewel‐ lery, metal artefacts and sculptures, mortars, paintings, pigments, pottery, raw materi‐ als, soils and clays, stone artefacts and sculptures can be easily analyzed by NAA.

**2.** Biomedicine: the samples and objects that can be analysed include: animal and human tissues activable tracers, bile, blood and blood components, bone, brain cell components and other tissues, breast tissue, cancerous tissues, colon, dialysis fluids, drugs and med‐ icines, eye, faeces, foetus, gallstones, hair, implant corrosion, kidney and kidney stones, liver, lung, medical plants and herbs, milk, mineral availability, muscle, nails, placenta, snake venom, rat tissues (normal and diseased), teeth, dental enamel and dental fillings,

In this work, we have used the INAA technique to analyse the traditional medicinal seeds prescribed for specific treatment purposes, were purchased from local markets [43]. The samples were irradiated at Es-Salam research reactor, at a power of 5 MW for 6 h. The accu‐ racy of the method was established by analyzing reference materials. Twenty elements were

determined, was found to vary depending on the seeds (Fig.11). The daily intake of essential and toxic elements was determined, and compared with the recommended values. The

probable cumulative intake of toxic elements is well below the tolerance limits.

**Element Unity Black seeds Fenugeek Caraway** Ba mg/Kg 7.7 ± 5.5 100.3 ± 5.8 112.4 ± 6.5 Br mg/Kg 136.9 ± 4.6 119.6 ± 3.9 72.9 ± 2.4 Ca g/Kg 3.77 ± 4.55 3.14 ± 0.39 1.50 ± 0.21 Ce mg/Kg 1.44± 0.07 2.6 ± 0.1 1.98 ± 0.11 Co mg/Kg 0.66 ± 0.02 0.73 ± 0.02 0.81 ± 0.03 Cr mg/Kg 4.44 ± 0.19 29.3 ± 1.0 2.96 ± 0.20 Cs mg/Kg 0.25 ± 0.01 0.51 ± 0.02 0.22 ± 0.01 Eu mg/Kg 0.022 ± 0.002 0.039 ± 0.002 0.023 ± 0.002 Fe mg/Kg 656.2 ± 71.6 823.2 ± 89.8 674.67 ± 74.16 K g/Kg 3.67± 1.79 3.75 ± 0.20 3.7 ± 0.2 La mg/Kg 0.74 ± 0.04 1.53 ± 0.06 1.50 ± 0.06 Na mg/Kg 1028 ± 34 804.20 ± 26.69 615.50 ± 20.41 Rb mg/Kg 24 ± 2 36.8 ± 1.4 26.3 ± 1.9 Sc mg/Kg 0,258 ± 0,037 0,362 ± 0,051 0,272 ± 0,008

Se mg/Kg 0,29 ± 0,04 ND ND

1 nd : not detected.

). The concentration of elements

many elements, usually trace elements, in the following fields and sample types:

168 Imaging and Radioanalytical Techniques in Interdisciplinary Research - Fundamentals and Cutting Edge Applications

thyroid, urine and urinary stones.

measured, with good accuracy and reproducibility (Table 61

**Figure 11.** Concentration of the major and minor (a) and trace (b) elements in the medicinal seed samples.

**3.** Environmental: in this domain, related fields concerned by NAA are: aerosols, atmos‐ pheric particulates (size fractionated), dust, fossil fuels and their ashes, flue gas, ani‐ mals, birds, insects, fish, aquatic and marine biota, seaweed, algae, lichens, mosses, plants, trees (leaves, needles, tree bark), household and municipal waste, rain and hori‐ zontal precipitations (fog, icing, hoarfrost), soils, sediments and their leachates, sewage sludges, tobacco and tobacco smoke, surface and ground waters, volcanic gases.

Recently, our laboratory is strongly involved in various areas of application of k0-NAA. The present work focuses on the application of the k0-NAA method in Nutritional and Health-Related Environmental field [44]. Tobacco holds a leading position among differ‐ ent commodities of human consumption. The adverse health effects of toxic and trace el‐ ements in tobacco smoke on smokers and non-smokers are a special concern. In the present study, the concentration of 24 trace elements in cigarette tobacco of five different brands of Algerian and American cigarettes have been determined by k0-based INAA method. The results were compared with those obtained for samples from Iranian, Turk‐ ish, Brazilian and Mexican cigarettes tobacco. To evaluate the accurate of the results the SRM IAEA-140/TM was executed.

A multi-element analysis procedure based on the k0-NAA method was developed at Es-Salam research reactor allowing to simultaneously determine concentrations for 24 ele‐ ments (As, Ba, Br, Ca, Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Na, Rb, Sb, Sc, Se, Sm, Sr, Ta, Tb, Th, Zn). The determination of toxic and trace elements in cigarette tobacco is impor‐ tant both from the point of view of health studies connected with smoking and more general aspects of the uptake of trace elements by plants (table 7). Because of its great sensitivity, k0-NAA method is very suitable for determination of heavy metals such as As, Sb, Se and Zn. The accuracy of the results was checked by the analysis of standard reference material and good agreement was obtained with certified or literature values. The results of Algerian tobacco (table 8) were compared with analyses of Turkey [45], Iran [46], Mexican [47] and Brazilian tobacco [48].

**Element**

**Designated sample code**

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**T1 T2 T3 T4 T5**

Sr 203.2 ± 7.8 136.9 ± 7.4 101.7 ± 4.7 82.37 ± 3.62 106.80 ± 5.39

Ta 0.021 ± 0.003 0.043 ± 0.006 0.023 ± 0.004 0.029 ± 0.004 0.023 ± 0.004

Tb 0.018 ± 0.004 0.021 ± 0.003 0.014 ± 0.004 0.008 ± 0.002 0.018 ± 0.004

Th 0.159 ± 0.009 0.32 ± 0.02 0.195 ± 0.014 0.153 ± 0.012 0.19 ± 0.02

Zn 68.06 ± 2.11 42.8 ± 1.4 40.24 ± 1.30 27.53 ± 0.89 42.99 ± 1.38

**Element Algeria Turkey Iran Mexican Brazilian**

Ba 100.3 – 101.3 64.6 1.15 ± 0.01 64 – 251 45.8 – 99.7

As 4.05 – 6.4 1.0 - < 0.55 – 3.24 -

Br 119.6 – 136.9 59.2 137 ± 2 49 -136 -

Ca % 3.14 – 3.77 - - - -

Cr 4.44 – 29.3 7.1 3.14 ± 0.14 < 0.8 – 2.4 -

Cs 0.25 – 0.51 0.20 0.17 ± 0.02 0.091 – 0.4 -

K % 3.67 – 3.75 2.6 0.220 ± 0.005 1.83 – 4.03 -

Na 804.2 – 1028 394 347 ± 18 309 – 566 -

Ce 1.44 – 2.6 - 1.19 ± 0.02 < 0.3 -1.7 1.2 – 8.3

Co 0.66 – 0.73 0.77 0.21 ± 0.01 0.29 – 0.55 0.70 – 1.2

Eu 0.022 – 0.039 0.034 0.045 ± 0.010 < 0.03 0.036 -0.037

Fe 656.2 – 823.2 1000 649 ± 6 420 – 680 710 – 4100

Hf 0.127 – 0.224 0.15 0.09 ± 0.01 < 0.03 – 0.13 0.15 – 0.87

La 0.74 – 1.53 1.0 0.62 ± 0.02 < 0.2 – 0.66 1.9 – 4.8

Rb 24.0 - 36.8 17.7 22.6 ± 3.6 19 – 50 30.3 – 45.0

Sb 0.089 – 0.180 0.10 0.68 ± 0.03 < 0.7 0.079 – 0.47

Sc 0.258 – 0.362 0.35 0.43 ± 0.03 0.13 – 0.22 0.23 – 1.50

**Table 7.** Concentration values (mg kg-1) of five brands of tobacco by k0-NAA method.


#### Concepts, Instrumentation and Techniques of Neutron Activation Analysis http://dx.doi.org/10.5772/53686 171


**Table 7.** Concentration values (mg kg-1) of five brands of tobacco by k0-NAA method.

Tb, Th, Zn). The determination of toxic and trace elements in cigarette tobacco is impor‐ tant both from the point of view of health studies connected with smoking and more general aspects of the uptake of trace elements by plants (table 7). Because of its great sensitivity, k0-NAA method is very suitable for determination of heavy metals such as As, Sb, Se and Zn. The accuracy of the results was checked by the analysis of standard reference material and good agreement was obtained with certified or literature values. The results of Algerian tobacco (table 8) were compared with analyses of Turkey [45],

170 Imaging and Radioanalytical Techniques in Interdisciplinary Research - Fundamentals and Cutting Edge Applications

**Designated sample code**

**T1 T2 T3 T4 T5**

As 4.05 ± 0.16 6.4 ± 0.24 2.16 ± 0.09 2.42 ± 0,09 4.27 ± 0.28

Ba 101.3 ± 5.5 100.3 ± 5.8 112.4 ± 6.5 83.1 ± 4.4 120.0 ± 7.7

Br 136.9 ± 4.6 119.6 ± 3.9 72.9 ± 2.4 54.1 ± 1.7 68.7 ± 2.3

Ca % 3.77 ± 4.55 3.14 ± 0.39 1.50 ± 0.21 2.11 ± 0.26 2.39 ± 0.31

Ce 1.44 ± 0.07 2.6 ± 0.1 1.98 ± 0.11 1.01 ± 0.05 1.81 ± 0.11

Co 0.66 ± 0.02 0.73 ± 0.02 0.81 ± 0.03 0.51 ± 0.02 0.78 ± 0.03

Cr 4.44 ± 0.19 29.3 ± 1.0 2.96 ± 0.20 2.37 ± 0.11 2.80 ± 0.22

Cs 0.25 ± 0.01 0.51 ± 0.02 0.22 ± 0.01 0.191 ± 0.008 0.42 ± 0.02

Eu 0.022 ± 0.002 0.039 ± 0.002 0.023 ± 0.002 0.021 ± 0.001 0.032 ± 0.002

Hf 0.127 ± 0.007 0.224 ± 0.015 0.24 ± 0.02 0.144 ± 0.014 0.143 ± 0.010

K % 3.67± 1.79 3.75 ± 0.20 3.7 ± 0.2 2.92 ± 0.14 3.38 ± 0 .18

La 0.74 ± 0.04 1.53 ± 0.06 1.50 ± 0.06 1.082 ± 0.043 1.68 ± 0.06

Na 1028 ± 34 804 ± 27 616 ± 20 653 ± 22 575 ± 19

Rb 24 ± 2 36.8 ± 1.4 26.3 ± 1.9 14.33 ± 0.59 25.4 ± 1.6

Sb 0.089 ± 0.014 0.180 ± 0.020 0.036 ± 0.007 0.127 ± 0.015 0.346 ± 0.037

Sc 0.258 ± 0.037 0.362 ± 0.051 0.272 ± 0.008 0.165 ± 0.023 0.264 ± 0.037

Sm 0.092 ± 0.004 0.18 ± 0.01 0.142 ± 0.005 0.095 ± 0.004 0.152 ± 0.005

Se 0.29 ± 0.04 ND ND ND ND

Fe 656 ± 72 823 ± 90 675 ± 74 384 ± 13 664 ± 24

Iran [46], Mexican [47] and Brazilian tobacco [48].

**Element**



**Element**

indicated by producer.

**Element Designated sample code**

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**M1 M2 M3**

Br 12.74 ± 0.81 38.9 ± 1.26 72.73 ± 0.56

Ca 9040 ± 150 **(**9300**)** 9560 ± 820**(**9600**)** 9210 ± 130

K 12970 ± 780 **(**12000**)** 12700 ± 700 **(**12600**)** 12700 ± 500

Na 280 ± 100 **(**3500**)** 33900 ± 100 **(**4400**)** 41400 ± 130

Rb 12.03 ± 0.08 14.7± 0.7 8.2 ± 0.8

Zn 48.03 ± 0.08 42.7 ± 0.2 42.4 ± 0.2

**Figure 12.** Comparison of k0-NAA data to certified values for IAEA-153 and IAEA-155.

neutron activation analysis to the proportioning of iodine in food salt [50].

**Table 9.** Concentration values of Milk: M1, M2 and M3; units are in mg/kg, NB: (value) is the concentration value of

The accuracy of the measurements was evaluated by analyzing two SRMs Whey powder AIEA-155 and Milk powder AIEA-153. The analysis results illustrated in figure 12 showed that the deviations between experimental and certified values were mostly less than 10%. As an example, an investigation in the nutrition field was carried out by the radiochemical

**8.** Quality assurance: this include analysis of reference materials, certification of element contents and homogeneity testing of mainly biological and environmental reference materials of chemical composition and methods inter-comparisons. Additional informa‐ tion about these applications can be found in the Proceedings of the Int. Symposia on Biological and Environmental Reference Materials (BERM). In 2012, Hamidatou L et all

**Table 8.** Comparison between our results (Algerian cigarettes tobacco) and those reported in the literature.



**Element Algeria Turkey Iran Mexican Brazilian**

172 Imaging and Radioanalytical Techniques in Interdisciplinary Research - Fundamentals and Cutting Edge Applications

Sm 0.092 – 0.180 - 0.88 ± 0.01 0.07 – 0.14 0.24 – 0.60

Th 0.159 – 0.320 0.32 0.177 ± 0.010 < 0.1 – 0.17 0.34 – 4.00

**Table 8.** Comparison between our results (Algerian cigarettes tobacco) and those reported in the literature.

**4.** Forensics: bomb debris, bullet lead, explosives detection, glass fragments, paint, hair,

**5.** Geology and geochemistry: asbestos, bore hole samples, bulk coals and coal products, coal and oil shale components, crude oils, kerosene, petroleum, cosmo-chemical sam‐ ples, cosmic dust, lunar samples, coral, diamonds, exploration and geochemistry, mete‐ orites, ocean nodules, rocks, sediments, soils, glacial till, ores and separated minerals.

**6.** Industrial products: alloys, catalysts, ceramics and refractory materials, coatings, elec‐ tronic materials, fertilizers, fissile material detection and other safeguard materials, graphite, high purity and high-tech materials, integrated circuit packing materials, on‐ line, flow analysis, oil products and solvents, pharmaceutical products, plastics, process control applications, semiconductors, pure silicon and silicon processing, silicon diox‐

ide, NAA irradiation vials, textile dyes, thin metal layers on various substrates.

**7.** Nutrition: composite diets, foods, food colours, grains, honey, seeds, spices, vegetables, milk and milk formulae, yeast. In this chapter, we focus on the application of the k0 method of instrumental neutron activation analysis in Nutritional and Health-Related Environmental field [49]. Three kinds of milk were purchased in the powder form from local supermarket. The samples of milk powder were analyzed using k0-NAA method. Concentrations of six elements Br, Ca, K, Na, Rb and Zn have been determined by long irradiation time with a thermal and epithermal flux of 4.7.1012 n.cm–2.s–1 and 2.29.1011 n.cm–2.s–1, respectively (see table 9). The reactor neutron spectrum and detection effi‐ ciency calibration parameters such as α, f and εp have been used for the calculation of elemental concentrations. The analytical results for three kinds of milk using k0-NAA are compared with the certified values of SRMs. In this work, we have determined six elements in three kinds of milk and two reference materials, IAEA-153 and IAEA-155. The elements Br, Ca, K, Na, Rb and Zn were determined in each kind of the three sam‐

Se 0.29 0.18 - < 0.7 -

Sr 136.88 – 203.20 - - 227 – 472 -

Ta 0.021 – 0.043 - - - -

Tb 0.018 – 0.021 - 0.034 ± 0.002 - -

Zn 42.80 – 68.06 35 12.6 ± 0.4 14 - 56 -

gunshot residue swabs, shotgun pellets.

ples of milk.

**Table 9.** Concentration values of Milk: M1, M2 and M3; units are in mg/kg, NB: (value) is the concentration value of indicated by producer.

**Figure 12.** Comparison of k0-NAA data to certified values for IAEA-153 and IAEA-155.

The accuracy of the measurements was evaluated by analyzing two SRMs Whey powder AIEA-155 and Milk powder AIEA-153. The analysis results illustrated in figure 12 showed that the deviations between experimental and certified values were mostly less than 10%.

As an example, an investigation in the nutrition field was carried out by the radiochemical neutron activation analysis to the proportioning of iodine in food salt [50].

**8.** Quality assurance: this include analysis of reference materials, certification of element contents and homogeneity testing of mainly biological and environmental reference materials of chemical composition and methods inter-comparisons. Additional informa‐ tion about these applications can be found in the Proceedings of the Int. Symposia on Biological and Environmental Reference Materials (BERM). In 2012, Hamidatou L et all reported "k0-NAA quality assessment in an Algerian laboratory by analysis of SMELS and four IAEA reference materials using Es-Salam Research reactor" the internal quali‐ ty control of the k0-NAA technique [51]. The concept of QC/QA, internal and external validation is considered as an advanced stage in the life cycle of an analytical method.

Es-Salam research reactor and all necessary equipments installed in the NAA department to

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175

Thanks are due to Dr Derdour Mohamed the responsible of COMENA and Mr Kerris Ab‐ delmoumen General Director of CRNB for financial support. Grateful acknowledgment is made to Mr Salhi Mhamed the director of techniques and nuclear applications division for his highly valuable assistance. Special thanks are due to all colleagues involved for their

Lylia Hamidatou, Hocine Slamene, Tarik Akhal and Boussaad Zouranen

Department of Neutron Activation Analysis, Nuclear Research Centre of Birine, Algeria

[1] Greenberg, R.R., et al., Spectrochimica Acta Part B, 66 issues 3-4; 2011, p193-241.

[4] De Corte, F., et al.,J. Radioanal. Nucl. Chem., volume 197; 1994, p93.

[7] Lin, X., Li, X., J. Radioanal. Nucl. Chem., volume 223; 1997, p. 47.

[5] Acharya, R., Chatt, A.,. J. Radioanal. Nucl. Chem., volume 257; 2003, p525.

[6] Simonits, A., De Corte, F., Hoste, J., J. Radioanal. Chem., volume 24; 1975, p. 31.

[8] Moens, L., De Corte, F., Simonits, A., De Wilspelaere, A., Hoste, J., J. Radioanal.

[9] De Corte, F., Simonits, A., De Wilspelaere, A., Hoste, J., J. Radioanal. Nucl. Chem.,

[10] Jovanovic, S., De Corte, F., Moens, L., Simonits, A., Hoste, J., J. Radioanal. Nucl.

[2] Bé, M. M., Chisté. V., BNM-LNHB/CEA- Tables des radionucléides,

[3] De Corte, F.,The k0 Standardization Method: A Move to the Optimization of NAA,

cover all steps of analytical process.

**Acknowledgments**

help during fifteen years.

**Author details**

**References**

01/12/01-6/4/2004 ; 2004.

Gent University; 1987.

Chem., volume 52 ; 1979, p. 379.

Chem., volume 82; 1984, p.379.

volume 113; 1987, p145.

Our contribution in this domain is considered as periodic activities. Since the Nineties our laboratory participated through AFRA/AIEA projects in different inter-laboratory proficien‐ cy tests. Recently, our laboratory was participated in four inter-comparison tests organized by IAEA within the framework of the AFRA project to assess the analytical performance of 18 analytical laboratories participating in the RAF /4/022 project, Enhancement of Research Reactor Utilization and Safety by taking part in analytical proficiency testing IAEA in con‐ junction with WEPAL, the Wageningen Evaluating Programs for Analytical Laboratories. The Proficiency Testing tests related to the determination of major, minor and trace elements in materials of the International Soil and Plant Analytical Exchange material (Wepal codes ISE, IPE).

**9.** Neutron flux characterization: theoretical and experimental study, calibration of irradi‐ ation channels, simulations using Monte Carlo Code. In general, the implementation of new techniques based on the neutron beams or flux around the research reactors needs the knowledge of the essential parameters of neutron flux in different sites to obtain a better precision during the development.

In this context, we give a great interest in the neutron study for our irradiation channels by making periodic calibrations using experimental and simulation approaches [11, 15, 52].
