Determination of trace concentration of boron in ADU by the nuclear track technique

A method for the determination of boron concentration in extracted (NH4)2 U2O7 x H2O (ADU) was used. One ml of the aqueous solution is irradiated with thermal neutrons from a 10 Ci Am/Be neutron source with a flux of 0.2 x 105 n x cm-2 x s-1 and thermal column in the IRT-5000 with a flux of about 107 n x cm-2 x s-1. The alpha-activity due to the reaction 10B(n, α)7Li is recorded by a CR-39 alpha track detector. After the exposure, the alpha tracks are made visible in an optical microscope at magnification of 800X by etching the detector in 6N NaOH, and the track density is determined using calibration curves of known concentrations of boron. The boron concentration of the extracted ADU was found to be 5 ppm. (author) 6 refs.; 6 figs