Hf and Ce co-doped yttrium lutetium silicate scintillation crystal and preparation method and application thereof
By using Hf and Ce co-doped yttrium lutetium silicate scintillation crystals, the shortcomings of Ce:LYSO scintillation crystals in high-fast decay efficiency applications have been overcome, and a scintillation decay time of less than 30 ns has been prepared, which is suitable for radiation detection and fast dynamic radiation imaging.
Patent Information
- Application Number
- CN202511111828.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-08
- Publication Date
- 2025-12-02
AI Technical Summary
Existing Ce:LYSO scintillation crystals are insufficient for applications requiring high and fast decay efficiency, especially in radiation detection and rapid radiation dynamic imaging.
A scintillation crystal of yttrium silicate co-doped with Hf and Ce was prepared by introducing Hf4+ ions into the Ce doping base and controlling their doping concentration in the crystal. The preparation method includes weighing raw materials, grinding, pressing, calcining and growing the crystal by Czochralski method. The growth conditions were optimized to obtain a scintillation decay time of less than 30 ns.
It enables the emission of blue-violet light under ultraviolet or X-ray excitation, and the scintillation decay time is shortened to 20-40 ns, which improves the radiation response speed and performance, and is suitable for radiation detection and rapid dynamic radiation imaging.
Smart Images
Figure CN121046079A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of scintillation crystal material preparation technology, and in particular to an Hf and Ce co-doped yttrium lutetium silicate scintillation crystal, its preparation method and application. Background Technology
[0002] Cerium-doped lutetium yttrium silicate scintillation crystal (Ce:LYSO) is an important nuclear radiation detection material. It possesses advantages such as high density, fast decay time, high light yield, and stable physicochemical properties, and has been widely used in nuclear medicine equipment, nuclear physics, and high-energy physics. Compared to lutetium silicate (Ce:LSO), Ce:LYSO reduces the background radiation of lutetium and also reduces raw material costs to some extent. Furthermore, the addition of Ce... 3+ As a luminescent center, it can efficiently emit bright blue-violet light when excited by high-energy rays, and has an extremely short decay time, which significantly improves the scintillator's scintillating performance.
[0003] Currently, the reported scintillation decay time of Ce:LYSO is about 35 ns. For some applications that require high and fast decay efficiency, such as radiation detection and rapid radiation dynamic imaging, the existing Ce:LYSO is difficult to meet the application requirements.
[0004] In view of this, it is necessary to design an improved Hf and Ce co-doped yttrium lutetium silicate scintillation crystal, its preparation method and application, in order to solve the above problems. Summary of the Invention
[0005] The purpose of this invention is to provide an Hf and Ce co-doped yttrium lutetium silicate scintillation crystal, its preparation method, and its application.
[0006] To achieve the above-mentioned objective, in a first aspect, the present invention provides an Hf and Ce co-doped yttrium lutetium silicate scintillation crystal, wherein the chemical formula of the yttrium lutetium silicate scintillation crystal is (Hf... x Ce y Y z Lu 1-x-y-z )2SiO5, where, 0 <x≤0.1,0<y≤0.05,0<z≤0.2。
[0007] Preferably, the yttrium lutetium silicate scintillation crystal, when excited by ultraviolet light or X-rays with a wavelength of 250-380 nm, has an emission spectrum peak in the range of 400-500 nm, emits blue-violet light, and has a scintillation decay time of 20-40 ns.
[0008] Secondly, the present invention provides a method for preparing Hf and Ce co-doped yttrium lutetium silicate scintillation crystal, comprising the following steps:
[0009] According to the chemical formula of yttrium silicate scintillation crystal (Hf... x Ce y Y z Lu 1-x-y-z The stoichiometric ratio of HfO2, CeO2, Lu2O3, Y2O3, and SiO2 for SiO5 is weighed, ground and mixed, and then compressed into tablets to obtain material blocks.
[0010] The material block is calcined to obtain a crystal precursor; the crystal precursor is grown by the Czochralski method in a protective atmosphere to obtain the yttrium lutetium silicate scintillation crystal.
[0011] Preferably, the calcination temperature is 1450-1600℃ and the time is 24-72h.
[0012] Preferably, the seed crystal used in the crystal precursor growth process is LYSO:Ce 3+ Crystals are grown at a rate of 0.5-2 mm / h and a rotation speed of 5-15 r / min.
[0013] Preferably, the growth temperature of the crystal precursor growth process is 1950-2050℃.
[0014] Preferably, the heating rate during the calcination process, from 20-25℃ to 1450-1600℃, is 2-5℃ / min.
[0015] Preferably, the protective atmosphere is nitrogen or argon.
[0016] Thirdly, the present invention provides an application of Hf and Ce co-doped yttrium lutetium silicate scintillation crystal in the field of radiation detection.
[0017] The beneficial effects of this invention are:
[0018] 1. The Hf and Ce co-doped lutetium yttrium silicate scintillation crystal provided by the present invention is obtained by co-doping tetravalent Hf ions (Hf...) into a Ce-doped lutetium yttrium silicate crystal. 4+ Hf was prepared. 4+ The introduction of [a specific substance] competes with oxygen vacancies and shallow electron traps in the crystal to capture electrons, and effectively reduces the concentration of electron traps, thereby effectively shortening the fluorescence and scintillation decay time of the crystal and improving the crystal's response speed to radiation.
[0019] 2. The preparation method provided by this invention can be achieved by controlling Hf 4+ By precisely controlling the co-doping concentration of ions, the light output and scintillation attenuation properties of the crystal can be controlled. The Hf and Ce co-doped yttrium lutetium silicate scintillation crystals can be applied to fields such as radiation detection and rapid radiation dynamic imaging. Attached Figure Description
[0020] Figure 1 An optical photograph of the Hf and Ce co-doped yttrium lutetium silicate scintillation crystal prepared in Example 1 of this invention;
[0021] Figure 2 The X-ray fluorescence emission spectra of Hf and Ce co-doped yttrium lutetium silicate scintillation crystals prepared in Examples 1, 2, and 3 of this invention are shown.
[0022] Figure 3 The scintillation decay curve of the Hf and Ce co-doped yttrium lutetium silicate scintillation crystal prepared in Example 1 of this invention is shown.
[0023] Figure 4 The scintillation decay curve of the Hf and Ce co-doped yttrium lutetium silicate scintillation crystal prepared in Example 2 of the present invention is shown.
[0024] Figure 5 The image shows the scintillation decay curve of the Hf and Ce co-doped yttrium silicate scintillation crystal prepared in Example 3 of this invention. Detailed Implementation
[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments.
[0026] It should also be noted that, in order to avoid obscuring the present invention with unnecessary details, only the structures and / or processing steps closely related to the present invention are shown in the accompanying drawings, while other details that are not closely related to the present invention are omitted.
[0027] Additionally, it should be noted that the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.
[0028] On one hand, the present invention provides an Hf and Ce co-doped yttrium lutetium silicate scintillation crystal with the chemical formula (Hf... x Ce y Y z Lu 1-x-y-z )2SiO5, where, 0 <x≤0.1,0<y≤0.05,0<z≤0.2。
[0029] When the crystal is excited by ultraviolet light or X-rays at a wavelength of 250-380 nm, the emission peak of the crystal is blue-violet light with a wavelength of 400-500 nm, and the scintillation decay time of the crystal is 20-40 ns.
[0030] On the other hand, the present invention also provides a method for preparing the above-mentioned Hf and Ce co-doped yttrium lutetium silicate scintillation crystal, comprising the following steps:
[0031] According to the chemical formula of yttrium silicate scintillation crystal (Hf... x Ce y Y z Lu 1-x-y-z The stoichiometric ratio of HfO2, CeO2, Lu2O3, Y2O3, and SiO2 for SiO5 is weighed, ground and mixed, and then compressed into tablets to obtain material blocks.
[0032] The material block was calcined to obtain a crystal precursor; the crystal precursor was grown by the Czochralski method in a protective atmosphere to obtain yttrium lutetium silicate scintillation crystal.
[0033] In some embodiments, the calcination temperature is 1450-1600℃, the time is 24-72h, and the heating rate of the calcination process from room temperature (20-25℃) to the target temperature is 2-5℃ / min.
[0034] In some embodiments, the protective atmosphere is an inert gas such as nitrogen or argon, which can be a fixed atmosphere or a flowing atmosphere. The specific selection method can be adjusted according to the actual application requirements, as long as it can meet the actual application requirements, and is not limited to this.
[0035] In some embodiments, the seed crystal used for crystal growth by the Czochralski method is LYSO:Ce 3+ Crystals, with a growth rate of 0.5-2 mm / h, a rotation speed of 5-15 r / min, and a growth temperature of 1950-2050℃.
[0036] The following specific embodiments further illustrate the Hf and Ce co-doped yttrium lutetium silicate scintillation crystal proposed in this invention, its preparation method, and its applications:
[0037] Example 1
[0038] This embodiment prepares an Hf and Ce co-doped yttrium lutetium silicate scintillation crystal with the chemical formula (Hf... 0.005 Ce 0.005 Y 0.1 Lu 0.8994 The specific preparation method of 2SiO5 includes the following steps:
[0039] According to the stoichiometric ratio of the above crystal chemical formula, weigh HfO2, CeO2, Lu2O3, Y2O3, and SiO2 (all with a purity greater than 99.99%), grind and mix them thoroughly, and press them into cake-shaped material blocks at 25°C using an electric tablet press.
[0040] The above material blocks were transferred into a crucible and calcined in air at a temperature of 1550°C for 72 hours. The temperature was increased from 25°C to 1550°C at a rate of 2.5°C / min during the calcination process. After calcination, the temperature was cooled to 25°C to obtain the crystal precursor.
[0041] The crystal precursor was transferred into an iridium crucible, which was then placed in a Czochralski furnace. The furnace was evacuated and filled with nitrogen. Under the nitrogen atmosphere, the precursor was heated by medium-frequency induction heating until it was completely melted and held for 4 hours. Then, the temperature was slowly lowered until the melt and the seed crystal reached a critical point where they could not melt or grow. The crystal was then necked appropriately to improve its quality. Crystal growth was then carried out at a growth rate of 1 mm / h and a rotation speed of 8 r / min. When the crystal grew to 3 mm, it was then subjected to shouldering (enlarging the crystal diameter to 23 mm with a shoulder length of 5 mm), constant diameter (maintaining the crystal diameter of 23 mm with a constant diameter length of 20 mm), and necking (reducing the crystal diameter to 5 mm with a necking length of 5 mm). After the preset growth program was completed, the crystal was automatically broken off and annealed at a rate of 20 °C / h to 25 °C, thus obtaining an Hf and Ce co-doped yttrium lutetium silicate scintillation crystal. It should be noted that, unless otherwise specified, the reagents and raw materials used in the embodiments of the present invention can be obtained by purchasing them from the market, and will not be described in detail here; in addition, the size of the crystal can be controlled by adjusting the size of the cake-shaped material block and the crystal growth program according to the required crystal size.
[0042] Optical photographs of the Hf and Ce co-doped yttrium lutetium silicate scintillation crystal prepared in this embodiment are shown below. Figure 1 As shown in the figure, the grown crystal is colorless and transparent, without macroscopic cracks or inclusions. The X-ray fluorescence emission spectrum of the crystal is as follows. Figure 2 As shown, the results indicate that the sample exhibits a broad emission peak in the range of 375-600 nm, with the main peak located at 410 nm. The sample displays bright blue-violet light. The scintillation decay curve is shown below. Figure 3 As shown, the results indicate that the fast decay component of the crystal sample is 27.01 ns (81.43%), and the slow decay component is 38.19 ns (18.57%).
[0043] Example 2
[0044] This embodiment prepares an Hf and Ce co-doped yttrium lutetium silicate scintillation crystal with the chemical formula (Hf... 0.05 Ce 0.005 Y 0.1 Lu 0.845 The specific preparation method of 2SiO5 includes the following steps:
[0045] According to the stoichiometric ratio of the above crystal chemical formula, weigh HfO2, CeO2, Lu2O3, Y2O3, and SiO2 (all with a purity greater than 99.99%), grind and mix them thoroughly, and press them into cake-shaped material blocks at 25°C using an electric tablet press.
[0046] The above material blocks were transferred into a crucible and calcined in air at a temperature of 1600℃ for 60 hours. During the calcination process, the temperature was increased from 25℃ to 1600℃ at a rate of 4℃ / min. After calcination, the temperature was cooled to 25℃ to obtain the crystal precursor.
[0047] The crystal precursor was transferred into an iridium crucible, which was then placed in a Czochralski furnace. The furnace was evacuated and filled with nitrogen. Under the nitrogen atmosphere, the precursor was heated by medium-frequency induction heating until it was completely melted and held for 5 hours. Then, the temperature was slowly lowered until the melt and the seed crystal reached a critical point where they could not melt or grow. The crystal was then necked appropriately to improve the crystal quality. Subsequently, crystal growth was carried out at a growth rate of 1.2 mm / h and a rotation speed of 10 r / min. When the crystal grew to 3 mm, it was then subjected to shoulder growth (increasing the crystal diameter to 23 mm), constant diameter growth (maintaining the crystal diameter of 23 mm), and necking growth (reducing the crystal diameter to 5 mm). After the preset growth program was completed, the crystal was automatically broken off and annealed at a rate of 15 °C / h to 25 °C, thus obtaining an Hf and Ce co-doped yttrium lutetium silicate scintillation crystal.
[0048] The X-ray fluorescence emission spectrum of the Hf and Ce co-doped yttrium lutetium silicate scintillation crystal prepared in this embodiment is as follows: Figure 2 As shown, the results indicate that the sample exhibits a broad emission peak in the range of 375-600 nm, with the main peak located at 410 nm. The sample displays bright blue-violet light. The scintillation decay curve is shown below. Figure 4 As shown, the results indicate that the fast decay component of the crystal sample is 24.81 ns (68.72%), and the slow decay component is 34.26 ns (31.28%).
[0049] Example 3
[0050] This embodiment prepares an Hf and Ce co-doped yttrium lutetium silicate scintillation crystal with the chemical formula (Hf... 0.07 Ce 0.01 Y 0.15 Lu 0.76 The specific preparation method of 2SiO5 includes the following steps:
[0051] According to the stoichiometric ratio of the above crystal chemical formula, weigh HfO2, CeO2, Lu2O3, Y2O3, and SiO2 (all with a purity greater than 99.99%), grind and mix them thoroughly, and press them into cake-shaped material blocks at 25°C using an electric tablet press.
[0052] The above material blocks were transferred into a crucible and calcined in air at a temperature of 1500℃ for 72 hours. The temperature was increased from 25℃ to 1500℃ at a rate of 2℃ / min during the calcination process. After calcination, the temperature was cooled to 25℃ to obtain the crystal precursor.
[0053] The crystal precursor was transferred into an iridium crucible, which was then placed in a Czochralski furnace. The furnace was evacuated and filled with nitrogen. Under the nitrogen atmosphere, the precursor was heated by medium-frequency induction heating until it was completely melted and held at that temperature for 6 hours. Then, the temperature was slowly lowered until the melt and the seed crystal reached a critical point where they could not melt or grow. The crystal was then necked appropriately to improve its quality. Subsequently, crystal growth was carried out at a growth rate of 1.5 mm / h and a rotation speed of 12 r / min. When the crystal grew to 3 mm, it was then subjected to shoulder growth (increasing the crystal diameter to 25 mm), constant diameter growth (maintaining the crystal diameter at 25 mm), and necking growth (reducing the crystal diameter to 5 mm). After the preset growth program was completed, the crystal was automatically broken off and annealed at a rate of 10 °C / h to 25 °C, thus obtaining an Hf and Ce co-doped yttrium lutetium silicate scintillation crystal.
[0054] X-ray fluorescence emission spectrum of crystals as follows Figure 2 As shown, the results indicate that the sample exhibits a broad emission peak in the range of 375-600 nm, with the main peak located at 410 nm. The sample displays bright blue-violet light. Combined with the X-ray fluorescence emission spectra of Examples 1 and 2, the emission peak intensity gradually decreases with increasing Hf doping concentration. The scintillation decay curve of the Hf and Ce co-doped yttrium lutetium silicate scintillation crystal prepared in this example is shown below. Figure 5 As shown, the results indicate that the fast decay component of the crystal sample is 23.55 ns (59.17%), and the slow decay component is 33.04 ns (40.83%).
[0055] In summary, the Hf and Ce co-doped yttrium lutetium silicate scintillation crystal prepared by this invention can be effectively excited by ultraviolet and X-rays to produce bright blue-violet light, and achieves a fast scintillation decay time of less than 30 ns, which is lower than the decay time of the previously reported yttrium lutetium silicate scintillation crystal (35 ns). It has great application prospects in fields such as fast radiation dynamic imaging.
[0056] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.
Claims
1. A Hf and Ce co-doped yttrium lutetium silicate scintillation crystal, characterized in that, The chemical formula of the yttrium lutetium silicate scintillation crystal is (Hf x Ce y Y z Lu 1-x-y-z )2SiO5, where, 0 <x≤0.1,0<y≤0.05,0<z≤0.2。 2. The yttrium lutetium silicate scintillation crystal according to claim 1, characterized in that, The yttrium silicate scintillation crystal, when excited by ultraviolet light or X-rays with wavelengths of 250-380 nm, has an emission spectrum peak in the range of 400-500 nm, emits blue-violet light, and has a scintillation decay time of 20-40 ns.
3. A method for preparing an Hf and Ce co-doped yttrium lutetium silicate scintillation crystal according to any one of claims 1-2, characterized in that, Includes the following steps: According to the chemical formula of yttrium silicate scintillation crystal (Hf... x Ce y Y z Lu 1-x-y-z The stoichiometric ratio of HfO2, CeO2, Lu2O3, Y2O3, and SiO2 for SiO5 is weighed, ground and mixed, and then compressed into tablets to obtain material blocks. The material block is calcined to obtain a crystal precursor; the crystal precursor is grown by the Czochralski method in a protective atmosphere to obtain the yttrium lutetium silicate scintillation crystal.
4. The preparation method according to claim 3, characterized in that, The calcination temperature is 1450-1600℃, and the time is 24-72h.
5. The preparation method according to claim 3, characterized in that, The seed crystal used in the crystal precursor growth process is LYSO4:Ce 3+ Crystals are grown at a rate of 0.5-2 mm / h and a rotation speed of 5-15 r / min.
6. The preparation method according to claim 5, characterized in that, The growth temperature for the crystal precursor growth process is 1950-2050℃.
7. The preparation method according to claim 4, characterized in that, The heating rate during the calcination process, from 20-25℃ to 1450-1600℃, is 2-5℃ / min.
8. The preparation method according to claim 3, characterized in that, The protective atmosphere is nitrogen or argon.
9. The application of the Hf and Ce co-doped yttrium lutetium silicate scintillation crystal according to any one of claims 1-2 or the Hf and Ce co-doped yttrium lutetium silicate scintillation crystal prepared by the preparation method according to any one of claims 3-8 in the field of radiation detection.
Citation Information
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