This article is cited in
4 papers
Spectroscopy of condensed matter
Color and luminescence centers in LuAG and LuAG : Pr crystals before and after $^{60}$Co $\gamma$-irradiation
A. Kh. Islamova,
E. M. Ibragimovaa,
I. A. Khayitova,
R. R. Vil'danovb,
M. Z. Amonova a Institute of Nuclear Physics, Academy of Sciences of Uzbekistan, Tashkent
b National University of Uzbekistan, Tashkent, 100174, Uzbekistan
Abstract:
The absorption and thermoluminescence spectra and their relaxation in pure and praseodymium-doped LuAG crystals are comparatively studied to determine the contribution of intrinsic and impurity defects before and after irradiation by
$^{60}$Co
$\gamma$-quanta with an average energy of 1.25 MeV, dose rate of 0.8 Gy/s, and dose of 10
$^3$ Gy at 310 K. The existence of intrinsic
$F^+$ defects with a typical absorption band at 375 nm and impurity Cr
$^{4+}$ centers absorbing at 285, 420, 490, and 595 nm in both LuAG and Pr:LuAG samples before irradiation is related to the crystal-growth technology and the impurity composition of the charge. An increase in the concentration of
$F^+$ and Cr
$^{4+}$ centers after
$\gamma$-irradiation is caused by charging of neutral
$F$ centers and changing of the electronic state (valence) of Cr
$^{3+}$ impurity centers. Formation of antisite defect complexes Lu
$^{3+}_{\mathrm{Al}}$–V
$_{\mathrm{O}}$, which are responsible for a luminescence band at 335 nm, is suggested. The first broad peak at 340 K on the thermoluminescence curves of both samples after irradiation with a dose of 10
$^3$ Gy is related to liberation of charge carriers from shallow trapping levels; thermal activation and radiative recombination with emitting centers begin at 310 K, which places the upper limit on the temperature range of application of these scintillation crystals.
Received: 10.01.2018
DOI:
10.21883/OS.2018.07.46265.5-18
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