Application of polyethylene naphthalate sheets to alpha particle discrimination in the use of 4πα-γ anti-coincidence spectroscopy

The applicability of polyethylene naphthalate (PEN) sheets for α-particle discrimination was investigated by both experimental and Monte Carlo (MC) simulation approaches. ²²³Ra source was sandwiched between two PEN sheets and utilized as a 4πα-detector. The 4πα-γ anticoincidence technique was employed to determine the individual α-efficiencies of ²²³Ra and its progeny. As a result, the discriminated α-efficiencies obtained from α-γ anticoincidence spectroscopy for 25, 38 and 50 μm PEN sheets were approximately 90% or higher, with β-contribution of 1% or less. In MC simulation, α-efficiency of approximately 100% was obtained for 38 and 50 μm thick PEN sheets, with β-contribution of 0.1%. Experimental α-efficiencies declined more sharply with increasing α-energy than those from simulations, likely due to the unmodeled self-absorption and scattering effects.