Thermoluminescence response in 60Co gamma rays, 100 MeV Si8+ and 150 MeV Au9+ irradiated Y2O3:Ho3+ nanophosphor

Abstract

Combustion synthesized nanocrystalline holmium (Ho) doped yttrium oxide (Y2O3) was irradiated with gamma (γ) rays, 100 MeV silicon (Si8+) and 150 MeV gold (Au9+) ions to investigate the thermoluminescent (TL) properties for dosimeter applications. No changes were observed in the crystal structure of the material even after it was exposed to the high energy ion beams. The sizes of the crystallites, however, decreased. The TL glow curves of the γ-irradiated samples showed a prominent peak at 419 K with a shoulder at 493 K. TL glow curves for the Si8+ and Au9+ ion irradiated samples showed maximum peaks centred at 407 K, 660 K and 465, 509 and 640 K. The TL glow curve peak intensity of the γ-irradiated samples increased upto a 3 kGy dose and then it decreased with a further increase in the dose but the position of the glow curve peak's temperature remained constant. The TL intensity of the Si8+ and Au9+ ions irradiated samples increased upto 5 × 1010 ions cm−2 of the fluence and then it decreased with a further increase in ion fluence. The glow curves' shapes were different from that of the gamma irradiated samples, because of different TL mechanisms involved. The TL curves were deconvoluted to calculate the kinetic parameters. The activation energy and the frequency factor are in the range of 0.90 eV–1.40 eV and 7.21 × 109−5.83 × 1014 s−1, respectively. The synthesized material exhibited longer TL lifetimes under the 150 MeV Au9+ ions to that of the 100 MeV Si8+ and gamma irradiated samples. The results demonstrated that Y2O3:Ho3+ possesses a high resistance to defect formation even at high electronic energy depositions. After swift heavy ion (SHI) irradiation the samples exhibited radiation resistance.