RU2736174C1 - Ceramics for recording high-dose ionizing radiations - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: invention can be used for recording high-dose ionizing radiations. Essence of invention consists in the fact that in ceramics for recording of high-dose ionizing radiations, consisting of nano-sized aluminium oxide in α-phase, additionally in structure of initial matrix Ba²⁺ cation is introduced, at following ratio of components, wt. %: aluminium oxide 97.25…97.41, Ba²⁺ cation 0.54…0.64, other impurities 1.95…2.21.

EFFECT: technical result is enabling increase in range and sensitivity of detectors when detecting high-dose ionizing radiations.

1 cl, 3 ex, 2 tbl, 2 dwg

Description

The invention relates to the field of optics and solid-state dosimetry, in particular to the development of compositions of ceramics made of aluminum oxide, including metal cations, which can be used as a basis in detectors when registering high-dose ionizing radiation.

Known ceramics in which to improve the properties as a dopant in the crystal lattice of aluminum oxide was introduced the cation Mn ²⁺ (by impregnation from the solution in terms of the cation Mn ²⁺ in the amount of 1%). Annealing conditions: in vacuum at 1500 ° С for 2 hours. FIG. 1, which shows the spectra of pulsed cathodoluminescence (PCL) of pure ceramics of nanosized Al ₂ O ₃ and ceramics doped with Mn ²⁺ and Ba ²⁺ cations (for example No. 1), obtained by annealing in vacuum at 1500 ° C for 2 hours. From which it is seen that for ceramics doped with Mn ²⁺ , the luminescence band at 400 nm disappears, and for the band at 693 nm, the intensity decreases; however, a new luminescence band with a maximum at 676 nm is formed. FIG. 2 shows the thermoluminescence (TL) curves of pure ceramics of nanosized Al ₂ O ₃ and ceramics doped with Mn ²⁺ and Ba ²⁺ cations (for example No. 1), obtained by annealing in vacuum at 1500 ° C for 2 hours, a significant decrease in intensity is observed peaks in the range of 460 K and 640 K for ceramics doped with Mn ²⁺ (SV Zvonarev, EI Frolov, VA Pankov, VY Churkin and K. Yu. Chesnokov. Luminescent properties of alumina ceramic doping with manganese // AIP Conference Proceedings 2015, 020128 ( 2018)). Therefore, the disadvantage of this composition is that it quenches the intrinsic luminescence of aluminum oxide, despite the appearance of the luminescence band of Mn ²⁺ itself at about 660 nm with a good intensity.

There is a composition of pure ceramics. The annealing temperature in vacuum was 1500 ° C for 2 hours, the PCL spectrum shows two luminescence bands with maxima at 400 and 693 nm (Fig. 1). On the TL curves (Fig. 2) after pulsed electron irradiation with a dose of 15 kGy, two peaks are recorded at 460 K and 640 K (V. Kortov, S. Zvonarev, A. Kiryakov, D. Ananchenko. Carbothermal reduction synthesis of alumina ceramics for luminescent dosimetry // Materials Chemistry and Physics 170 (2016) 168-174). This ceramic has good luminescence intensity and its own luminescence bands. However, a disadvantage is still the impossibility of the appearance of new luminescence bands in the PCL spectrum and new luminescence peaks in the TL curves. And additionally the impossibility of increasing its own luminescence under the given synthesis conditions.

The technical result is to increase the range and sensitivity of the detectors when registering high-dose ionizing radiation. The technical result is achieved by the fact that the Ba ²⁺ cation is additionally introduced into the structure of the initial matrix into the ceramics for recording high-dose ionizing radiation, consisting of nanosized aluminum oxide in the α-phase, with the following ratio of components, wt%:

aluminium oxide 97.25 ... 97.41 Ba cation ²⁺ 0.54 ... 0.64 other impurities 1.95 ... 2.21

Examples of specific execution

Example 1.

The sample was obtained as a result of multi-stage synthesis. Al ₂ O ₃ powder in the α-phase of "chemically pure" grade 99.2% with particle sizes in the range of 20-150 nm was pressed under a pressure of 0.5 GPa into compact discs with a diameter of 10.00 ± 0.05 mm and a thickness of 1.0 ± 0.1 mm. After that, preliminary annealing was carried out for 30 minutes at a temperature of 450 ° C in air to strengthen the material. Next, compact No. 1 was soaked in a solution containing barium nitrate with a concentration of 1% for the Ba ²⁺ cation for 30 minutes. And after drying in air, the last stage was the main annealing in vacuum (0.013 Pa) at a temperature of 1500 ° C for two hours to create additional luminescence centers. After annealing, X-ray fluorescence analysis (XRF) of ceramics Al ₂ O ₃ : 1% Ba ²⁺ was carried out and it turned out that 0.64 wt.% Entered the structure of the initial matrix. % Ba ²⁺ (see Table 1).

Example 2.

The preparatory stage for obtaining a compact before impregnation in a solution and its subsequent annealing in vacuum is carried out analogously to example 1.

According to the results of X-ray fluorescence analysis (XRF) of ceramics Al ₂ O ₃ : 1% Ba ²⁺ in this sample contains 0.54 wt. % Ba ²⁺ (see Table 1).

Example 3.

The preparatory stage for obtaining a compact before impregnation in a solution and its subsequent annealing in vacuum is carried out analogously to example 1.

According to the results of X-ray fluorescence analysis (XRF) of ceramics Al ₂ O ₃ : 1% Ba ²⁺ in this sample contains 0.61 wt. % Ba ²⁺ (see Table 1).

The intensity of the PCL in the 400 nm and 693 nm bands increased compared to the pure ceramics (Fig. 1). According to the TL curves, the following changes occurred: new peaks with maxima at 380 and 570 K appeared, the intensity of the peak with a maximum at 640 K increased (Fig. 2).

PCL measurements were carried out on a KLAVI spectrometer with a recording spectrum range of 300-700 nm with an electron beam pulse duration of 2 ns, the electron energy per pulse was 130 ± 10 keV with a density of 60 A / cm ² . TL measurements were carried out using the "Gray" dosimetric system in the temperature range of 300-670 K at a heating rate of 2 K / s with a photomultiplier recording range of 230-700 nm.

Outside the indicated concentration limits of Ba ^{2+, there are no} data on the PCL bands and TL peaks.

Table 2 shows the comparative characteristics of the physical properties, the proposed composition and the composition selected as a prototype. FIG. 1 and FIG. 2 for the proposed ceramics Al ₂ O ₃ : 1% Ba ²⁺ shows the averaged data of three compositions (compact No. 1-No. 3 from examples 1-3).

It can be seen from the results of the tables that the proposed composition of ceramics has a higher intensity of PCL in the bands of 400 (on average by 67%) and 693 nm (on average by 39%). According to the TL curves, the intensity of the peak with a maximum at 640 K increased by an average of 91% (with an insignificant decrease in the intensity of the peak with a maximum at 460 K by an average of 9%), and two new peaks with maxima at 380 and 570 K also appeared. When using such ceramics in the registration of high-dose ionizing radiation, this will increase both the sensitivity of the used detector (a higher intensity of the luminescence bands of the initial matrix - according to PCL data, and the intensity of the peak at a maximum of 640 K - according to TL data) and the range of registration of ionizing radiation (the appearance of new "marks" - peaks with a maximum at 380 and 570 K - according to TL data).

Claims (2)

Ceramics for recording high-dose ionizing radiation, consisting of nanosized aluminum oxide in the α-phase, characterized in that the Ba ²⁺ cation is additionally introduced into the structure of the initial matrix, with the following ratio of components, wt%: aluminium oxide 97.25 ... 97.41 Ba cation ²⁺ 0.54 ... 0.64 other impurities 1.95 ... 2.21

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