Fiber-optic Thermometer Using Afterglow Phosphorescence from Long Duration Phosphor

Low temperature thermoluminescence properties of Eu2+ and R3+ doped CaAl2O4

“…persistent luminescence) [2][3][4][5]. This observation has awaken interest towards these materials due to an increasing number of important applications including radiation detectors [6], sensors for structural damage [7,8], and temperature [9], in addition to traditional luminous paints [10]. The detailed mechanisms for the persistent luminescence are not yet understood, however.…”

Simple TWRC technique by using optical fiber

“…The TWRC technique allowed the signal to be scanned on cavity length, instead of on frequency modulation. The optical fiber tip or ''free end" has been used as thermometer probe by measuring the temperature dependence of the after-glow phosphorescence intensity of SrAl 2 O 4 :Eu 2+ , Dy 3+ [3], and by measuring fluorescence lifetime that varies with temperature of Cr-doped YAG crystal [4]. In photothermal technique, the optical fiber has been used for trace compounds detection in water using the deflection of water meniscus [5], as position sensitive detector in photothermal deflection technique [6], and mostly as merely channeling the modulated light from laser diode to the foil particularly in TWRC technique [1].…”

Characteristics of long afterglow phosphorescent calcium aluminate crystals for fluorescence thermometer application

“…Long afterglow phosphorescent SrAl 2 O 4 crystals including traps with high concentration are found to be a highly sensitive sensor head material with long temperature coefficient [8,9]. The high temperature coefficient of a SrA1 2 O 4 based sensor head is due to the thermal excitation process of trapped carriers at the trap levels with E ¼ 0:5 eV [8,9].…”

“…The high temperature coefficient of a SrA1 2 O 4 based sensor head is due to the thermal excitation process of trapped carriers at the trap levels with E ¼ 0:5 eV [8,9]. In addition to SrAl 2 O 4 phosphors, Eu doped CaAl 2 O 4 co-doped with rare earth elements as the auxiliary activators are also expected to be highly sensitive sensor head materials because of their high trap density.…”

“…In addition to SrAl 2 O 4 phosphors, Eu doped CaAl 2 O 4 co-doped with rare earth elements as the auxiliary activators are also expected to be highly sensitive sensor head materials because of their high trap density. [8,9]. The phosphor specimens, 5 mm in diameter and 2 mm thick, were sliced from the grown crystals.…”