Internal irradiation effects in239Pu doped K2Ca2(SO4)3): EPR,TSL and PAS investigations

The electron/hole trapped centres created during internal irradiation in²³⁹Pu doped K₂Ca₂(SO₄)₃ were investigated using electron paramagnetic resonance (EPR), thermally stimulated luminescence (TSL) and photoacoustic spectroscopic studies (PAS). These techniques were used to identify the defects and characterize the thermally induced relaxation processes. TSL studies of self (α)/γ-irradiated²³⁹Pu doped K₂Ca₂(SO₄)₃ revealed two glow peaks around 400 and 433K. Plutonium introduced as Pu⁴⁺ was partly reduced to Pu³⁺ due to self irradiation. This was ascertained from PAS studies. EPR studies carried out on these samples showed the formation of radical ions SO ₄ ⁻ , SO ₃ ⁻ , O ₃ ⁻ , etc. The thermal destruction of SO ₄ ⁻ ion was found to be associated with the prominent glow peak around 433K. Pu³⁺ was found to act as luminescent centre for the observed TSL glow. The trap depth for the glow peak at 433K has been determined from TSL and EPR data.