Short Irradiation Activation Analysis:

involves irradiation of the sample for a very short duration (1-600s) and counting after a delay of 20 to 100 ms. It is particularly useful for the determination of elements with very short half life of the order of few seconds. It has the benefits of low turn around time and high throughput. A fast irradiation measurement system (FIMS) using TRIGA Mark II reactor has been developed. Short time instrumental NAA, with high by, sensitivity and accuracy without matrix interferences can be achieved in spite of the initial high count rate from both short and long lived nuclide activation. Some typical examples are;

¹¹B(n, γ)¹²B (t_1/2 = 20.4 ms,E_γ =4.44 MeV);

^11B(n, α)⁸Li (t_1/2 = 844 ms,E_max  of β =12.5 MeV);

¹²C(n, p12⁵B (t_1/2 = 20.4 ms,E_γ =4.44 MeV);

¹³C(n, p)¹³B (t_1/2 = 17.3 ms,E_γ =3.68 MeV);

Short time NAA (ti = 30 s) for the analysis of trace elements in honey has been performed. The technique has the advantage of being free from radiation hazards.