Luminescence of LaBr3: Ce,Hf crystals under photon excitation in the ultraviolet, vacuum ultraviolet, and X-ray ranges

Abstract

Abstract-This study has been carried out using synchrotron radiation, time resolved luminescence ultraviolet and vacuum ultraviolet spectroscopy, optical absorption spectroscopy, and thermal activation spectroscopy. It has been found that, in scintillation spectrometric crystals LaBr 3 : Ce,Hf characterized by a low hygroscopicity, along with Ce 3+ centers in regular lattice sites, there are Ce 3+ centers located in the vicinity of the defects of the crystal structure. It has also been found that the studied crystals exhibit photoluminescence (PL) of new point defects responsible for a broad band at wavelengths of 500-600 nm in the PL spectra. The minimum energy of interband transitions in LaBr 3 is estimated as E g ~ 6.2 eV. The effect of multiplication of electronic excitations has been observed in the range of PL excitation energies higher than 13 eV (more than 2E g ). Thermal activation studies have revealed channels of electronic excitation energy transfer to Ce 3+ impurity centers.

Defect-related luminescence in KLuP2O7 doped with Pr3+ ions after irradiation with fast electrons and neutrons

“…Cerium ions are in favor for industry, but praseodymium has shorter decay time, and its emission is located at shorter wavelengths. In comparison with impurity Ce 3+ ions, praseodymium emission is located in higher energy region and has shorter lifetime (20-30 ns instead of 30-60) [4][5][6][7][8][9].…”

Люминесцентная спектроскопия фосфатов, легированных ионами Pr-=SUP=-3+-=/SUP=-, облученных быстрыми электронами и реакторными нейтронами

“…В сцинтилляционной практике в настоящее время чаще используются примесные ионы Ce 3+ , но у соединений с примесью ионов Pr 3+ наблюдается более короткое время распада, и спектр излучения локализован в более коротковолновой области спектра. По сравнению с примесными ионами Ce 3+ кинетика затухания межконфигурационных d− fпереходов в ионах Pr 3+ характеризуется временем затухания 20−30 ns вместо 30−60 ns у ионов Ce 3+ [4][5][6][7][8][9].…”