Co-doped thallium-doped cesium iodide scintillation crystal, preparation method thereof and applications thereof

Abstract

The invention relates to a co-doped thallium-doped cesium iodide scintillation crystal, a preparation method thereof and applications thereof. The scintillation crystal has a chemical composition of (Cs[1-x-y]Tl[x]RE[y])(I[1-y]X[3y]) or (Cs[1-x-y]Tl[x]Yb[y])(I[1-y]X[2y]), wherein the trivalent co-doped element RE is at least one selected from trivalent lanthanum (La), lutecium (Lu) and ytterbium (Yb); a divalent co-doped element is divalent Yb; the X is at least one selected from F, Cl, Br and I; the x is more than 0 and not more than 0.05; and the y is more than 0 and not more than 0.05. By co-doping, the photon yield of the scintillation crystal is not influenced on one hand, and the afterglow of the thallium-doped cesium iodide scintillation crystal is inhibited on the other hand, and therefore the co-doped thallium-doped cesium iodide scintillation crystal can be widely applied for X-ray safety detection, nuclear medicine, and other nuclear radiation detection technologies.

Description

technical field [0001] The invention relates to the technical field of inorganic compound crystals and manufacture, in particular to a thallium-doped cesium iodide scintillation crystal capable of suppressing the afterglow of the thallium-doped cesium iodide scintillation crystal, a preparation method and an application thereof. Background technique [0002] Thallium-doped cesium iodide (CsI:Tl) crystal is a kind of weakly deliquescent halide scintillator with excellent performance. Its light output is 85% of that of NaI:Tl. The suitable emission wavelength of 550nm can be effectively coupled with silicon photodiodes. This greatly simplifies the readout system of the detector, coupled with the advantages of high symmetry of the crystal structure, easy growth of large-sized crystals, and low price, the material has been widely used in nuclear medical imaging, security inspection, and high-energy physics. However, the long afterglow characteristics of CsI:Tl not only cause the...

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Problems solved by technology

The co-doping of the above ions can indeed effectively suppress the afterglow intensity, but it only has a significant inhibitory effect on the afterglow intensity in a short period of time, and the long-term afterglow inhibition effect is not obvious.

Or although the afterglow is suppressed, the light yield of the crystal is significantly reduced after co-doping, which greatly damages the original scintillation performance of the CsI:TI crystal

The reason for this effect may be that the introduced co-doped ions also serve as luminescent centers, and some of the electrons captured will be thermally ionized again at room temperature, and then these electrons will be [(Tl + )V k ] The luminescent center recaptures and recombines with holes to emit light, which causes a longer afterglow in seconds or minutes; while the rest of the electrons captured by the luminescent center will radiate and emit light after recombining with holes in the center, but the lifetime of this part of the luminescence Also in microseconds, milliseconds or even longer, resulting in loss of light yield, weakening the luminous advantages of the crystal

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