**2.6. Detection limits of NAA**

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

$$\text{DL} = \text{2.71} + \text{4.65B} \,\text{A} \tag{26}$$

tion, typical detection limits as derived from the analysis of a plant and a soil material. Peter Bode in his PhD thesis, Instrumental and organizational aspects of a neutron activation anal‐ ysis laboratory, the typical detection limits as derived from the analysis of a plant and a soil

Concepts, Instrumentation and Techniques of Neutron Activation Analysis

http://dx.doi.org/10.5772/53686

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**Element Plant Soil Element Plant Soil Element Plant Soil** NA 2 10 Nd 0.7 8 Ag 0.2 2 Ca 700 4000 Eu 0.006 0.05 Sn 10 20 Cr 1 1 Yb 0.03 0.2 Te 0.3 3 Co 0.02 0.3 Hf 0.01 0.1 Ba 10 40 Zn 0.4 6 W 0.3 1 Ce 0.2 1 As 0.2 0.8 Os 0.1 0.6 Sm 0.01 0.03 Br 0.3 0.8 Au 0.003 0.01 Tb 0.008 0.1 Sr 5 60 Th 0.01 0.1 Lu 0.004 0.02 Mo 4 10 K 200 1500 Ta 0.01 0.2 Cd 3 8 Sc 0.001 0.02 Re 0.08 0.2 Sb 0.02 0.2 Fe 8 100 Ir 0.0006 0.004 Cs 0.02 0.3 Ni 2 30 Hg 0.05 0.4 La 0.1 0.3 Ga 2 10 U 0.2 2 Se 0.1 1 Rb 0.4 6 Zr 5 80

**Table 5.** Detection limits of elements in mg.kg-1 as observed in NAA procedure of plant material and a soil material.

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

material given in table 5 [26].

**3. 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 interference.

However, practically, the INAA detection limits depend on:


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‐ tion, typical detection limits as derived from the analysis of a plant and a soil material. Peter Bode in his PhD thesis, Instrumental and organizational aspects of a neutron activation anal‐ ysis laboratory, the typical detection limits as derived from the analysis of a plant and a soil material given in table 5 [26].


**Table 5.** Detection limits of elements in mg.kg-1 as observed in NAA procedure of plant material and a soil material.
