Abstract:
The fast neutron activation analysis technique was conducted to determine fluorine in inorganic samples. The method utilised ¹⁹F(n,α) ¹⁶N reaction and a 5Ci (185GBq) ²³⁸Pu-Be neutron source. Samples, loaded in a rabbit with 21 mm in diameter and 60 mm long, were activated for 40 seconds, due to short half-life of ¹⁶N (7.14 seconds), and transferred to measuring unit in about 1.5 seconds by a home-made pneumatic transfer system. The gamma-ray detection system consisted of two opposing, matched cylindrical NaI(Tl) crystals3× 3 and 5× 5 connected to a single channel analyzer. The samples were counted for 20 seconds. This cycle was repeated 10 times and the cumulative counts in 200 seconds were recorded. The detection limit was found to be about 75 mg with relative error of less than 2 percent.