Compositional characterization of materials using neutron induced chain reaction based NAA methodologies

The concept of thermal neutron induced in-situ chain reactions is less explored for compositional analysis of materials. One such methodology (Equation I and II) was utilized for the production of ¹⁸F (t_1/2: 109 min, β⁺ emitter) with high specific activity for medical purpose using enriched lithium hydroxide or lithium carbonate. if a material has elements such as Li and O, the measurement of ¹⁸F can provide information on Li and O contents based on the nuclear chain reaction. The presence of both Li and O is required for the generation of ¹⁸F and the activity depends both on the numbers of Li and O atoms present in the sample. This concept is recently employed for the determination of Li and O content in lithium titanate (LTO) which is used as anode material (Li₄Ti₅O₁₂) in lithium ion battery and solid breeder blanket material (Li₂TiO₃) for tritium production in International Thermonuclear Experimental Reactor. The limits of detection (LOD) of Li and O are given herein, which are inferior compared to other existing methods. With the utilization of high neutron flus nuclear reactors (>10¹³ cm^-2 s^-1) such as Apsara-U instead of currently used facility with neutron flux ~10⁷ cm^-2 s^-1, there will be many fold improvement in LOD and ppm (mg kg^-1) level analysis can be done using neutron induced chain reaction. The method developed, can also be utilized for the compositional determination of lithium zirconate, lithium niobate, lithium silicate and also for the determination of oxygen in various kinds of samples (high melting oxides) in which traditional methods face difficulty. The method developed for Li and O, require no special arrangement, can be performed offline and the associated radiation hazard is negligible compared to that of the existing methods available based on neutron activation