Internal irradiation effects in ~(239)Pu doped K_2Ca_2(SO_4)_3: EPR, TSL and PAS investigations

摘要

The electron/hole trapped centres created during internal irradiation in ~(239)Pu doped K_2Ca_2(SO_4)_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-irradiated ~(239)Pu doped K_2Ca_2(SO_4)_3 revealed two glow peaks around 400 and 433 K. Plutonium introduced as Pu~(4+) was partly reduced to Pu~(3+) 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 433 K. Pu~(3+) was found to act as luminescent centre for the observed TSL glow. The trap depth for the glow peak at 433 K has been determined from TSL and EPR data.