Feasibility of using LiMnO₂ batteries for nuclear forensics

Lithium-ion batteries, which are widely used in consumer electronics, have the potential to serve as neutron detectors after a nuclear detonation. Their small size permits collection of many samples for subsequent investigations. Besides a large cross section in the ⁶Li(n,α)³H reaction, there are multiple possible neutron threshold detector materials in the battery. Inductively coupled plasma mass spectrometry provided detailed material information on a coin-cell LiMnO₂ battery. With this trace element analysis measuring Fe, Mn, Cr, Ni, Al, Na, Cu and Co, the possible reactions, their threshold energies and products were tabulated. This study performed MCNP modeling of battery exposure to neutrons from a detonation and comparison to experimental results from reactor irradiated batteries. As nearly all of the resulting radionuclides are photon emitters, the gamma spectrum can be obtained without disassembling the batteries. Two sets of gamma spectra were measured 1 to 3 days after the exposure to mimic the latency anticipated between device detonation and the collection and measurement of samples in the event of an actual incident.