NEUTRON ACTIVATION ANALYSIS (NAA) USING NIRR-1

The first nuclear research reactor in Nigeria is NIRR-1 (i.e. the Nigeria Research Reactor-1) sited at CERT. The Licensed thermal power level is 31 kW corresponding to a maximum neutron flux of 1 x 10¹² n/cm². NIRR-1 is presently used mostly for Neutron Activation analysis (NAA).

NAA is a non-destructive multi-elemental method for determining the concentrations of different elements in a material bombarded by neutrons. This is achieved through the registration of gamma radiation resulting from neutron bombardment. The energy of the gamma radiation and the half-life are element specific. Thus, qualitative and quantitative evaluation of individual elements present can be derived from the quantity of measured radiation.

Two analytical procedures for INAA with NIRR-1 facilities have been developed. The first analytical procedure involves a short irradiation regime followed by gamma-ray measurements after appropriate decay periods and it is suitable for quantifying the following elements: Al, Br, Ca, Cd, Cl, Dy, I, K, Mn, Na, Ti, V and Zn. The second analytical procedure involves a long irradiation regime of approximately 6-7 hours for quantifying the following elements: As, Au, Ba, Ce, Co, Cr, Cs, Eu, Fe, Ga, Gd, Hf, Ho, La, Lu, Nd, Rb, Sb, Sc, Se, Sm, Sr, Ta, Tb, Th, U, Yb, W, and Zn. Table 1 shows the irradiation and measurement regimes for the NAA with NIRR-1.

Table 1 Routine irradiation and measuring regimes using NIRR-1 facilities

SCHEDULE OF FEES FOR NAA ANALYSIS

ADDITIONAL INFORMATION FOR NAA

For samples that need further handling before packaging, additional fees are to be charged. The Turn around times for Short irradiation is within 1 week and Long irradiation is within 1 month. Academic researchers and students may apply for reduced charges. Clients are required to describe the particular of their projects and analytical needs in terms of element of interest before submitting samples. The charges are subject to periodic review.