Doped lithium molybdate scintillation crystal and preparation method thereof

Abstract

The invention relates to a doped lithium molybdate scintillation crystal material and a preparation method thereof, and belongs to the field of crystal growth technology and radiation detection. Aiming at the problem of poor luminescence property of the existing lithium molybdate crystal at room temperature, the invention provides an alkali metal ion doping strategy, a sodium-containing compound (Na2CO3, Na2MoO4 or Na2Mo2O7) is selected as a doping source, and crystal growth is realized through a Bridgman-Stockbarger method. Experiments show that the doping of the sodium-containing compound improves the luminescence property of the lithium molybdate crystal. According to the technical scheme, the luminescent property of the crystal can be improved, and the practical application of the crystal in a low-temperature crystal calorimeter device is further promoted.

Description

Technical Field

[0001] The present invention relates to the field of scintillation crystal materials, in particular to a doped lithium molybdate scintillation crystal material and a preparation method thereof. Background Art

[0002] Neutrinoless double beta decay (0νββ) is an extremely rare nuclear decay mode that particle physicists and nuclear physicists are actively searching for. It is the only way to detect whether neutrinos and antineutrinos are Majorana particles. 100 Mo is an ideal detector material for low-temperature crystal calorimetry (LCC) instruments used in ovββ research due to its high Q value (3034.4 keV), moderate natural isotopic abundance (9.67%), and feasibility of gas centrifugation. These experiments require high molybdenum concentrations in the bulk, high energy resolution, ultra-low radiation background, and large single crystals. This makes molybdates of light alkali metals, such as lithium and sodium, the most promising scintillating crystal materials for use in microcalorimetric detectors to search for ovββ.

[0003] As a detection material for low-temperature crystal calorimeter devices, Li2MoO4 crystals have the following advantages: 100 The Mo isotope (about 55%), high intrinsic radioactivity purity, absence of long-lived radioactive cationic isotopes, ability to effectively distinguish between α and β (γ) events, and low melting point of the crystal (705°C). However, the luminescence intensity of Li2MoO4 crystals at room temperature is very weak, limiting its application range. Summary of the Invention

[0004] In view of the problem that the existing Li2MoO4 crystal has poor luminescence performance, the purpose of the present invention is to provide a doped lithium molybdate scintillation crystal material and a preparation method thereof, which significantly improves the luminescence performance of the crystal by optimizing the doping scheme.

[0005] In one aspect, the present invention provides a doped lithium molybdate scintillation crystal material, wherein the crystal material is doped with a sodium-containing compound.

[0006] Preferably, the sodium-containing compound is Na2CO3, Na2MoO4 or Na2Mo2O7.

[0007] Preferably, the doping amount of the sodium-containing compound is 0.6-2 mol%.

[0008] Preferably, the sodium-containing compound is Na2CO3, and the doping amount of Na2CO3 is 1 mol%.

[0009] Preferably, the sodium-containing compound is Na2MoO4, and the doping amount of Na2MoO4 is 0.8 mol%.

[0010] Preferably, the sodium-containing compound is Na2Mo2O7, and the doping amount of Na2Mo2O7 is 0.7-1.1 mol%.

[0011] According to another aspect of the present invention, a method for preparing the above-mentioned doped lithium molybdate scintillation crystal material is provided, comprising the following steps:

[0012] Step 1: preparing lithium molybdate and sodium-containing compound raw materials;

[0013] Step 2: According to the required doping amount, the lithium molybdate raw material and the sodium compound raw material are mixed and ground to obtain a crystal growth raw material;

[0014] Step 3: growing the obtained crystal growth raw material in an air atmosphere by a crucible drop method to obtain a doped lithium molybdate scintillation crystal material.

[0015] Preferably, in step 1, lithium molybdate and part of the sodium-containing compound raw materials are synthesized by an aqueous solution method.

[0016] Preferably, the mixing and grinding in step 2 is performed by mechanical mixing.

[0017] Preferably, the crystal growth in step 3 uses lithium molybdate crystals as seed crystals.

[0018] The technical solution of this invention significantly improves the luminescence properties of Li2MoO4 crystals through doping. Comparative studies using various sodium-containing compounds ultimately identified the optimal dopant compound and doping ratio for significantly enhancing the luminescence properties of Li2MoO4 crystals. The core of this technology lies in the formation of new defect structures through the rational selection and doping of sodium-containing compounds, effectively improving the luminescence properties of Li2MoO4 crystals. This technology meets the requirements of low-temperature crystal calorimeters for detection materials and further promotes applied research in neutrinoless double-beta decay experiments.

[0019] Experiments show that all sodium-containing compounds enhance the luminescence properties of Li2MoO4 crystals, with Na2Mo2O7 doping being the most effective. The preferred doping range is 0.7 to 1.1 mol%, with 0.8 mol% achieving the best results, reaching approximately nine times that of undoped crystals.

[0020] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0021] 1. The technical solution of the present invention provides a doped lithium molybdate crystal, specifically a sodium compound (Na2CO3, Na2MoO4 or Na2Mo2O7) doped lithium molybdate crystal. Compared with undoped lithium molybdate crystal, the luminescence performance is improved, among which the Na2Mo2O7 doping effect is the most obvious.

[0022] 2. Through experiments on different doping concentrations, the doping range of Na2Mo2O7 was determined to be 0.6~2mol%, among which the optimal doping range was 0.7~1.1mol%. The best effect was achieved with a doping amount of 0.8mol%, which was about 9 times that of the undoped crystal, significantly improving the luminescence efficiency of the crystal.

[0023] 3. The preparation method of the technical solution of the present invention is simple and easy. The aqueous solution method and the crucible drop method are used, which is conducive to the preparation of large-scale, high-quality crystals and further promotes their application in neutrinoless double-beta decay experiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Other features, objects and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings.

[0025] Figure 1 The photographs of the crystal blanks of Examples 1-8 of the present invention with different doping amounts of xNa2Mo2O7:Li2MoO4 (x=0.5-1.2%) are shown;

[0026] Figure 2 The 1 mol% Na2Mo2O7:Li2MoO4 crystals grown in Example 5 of the present invention were ground into powder and subjected to XRD phase analysis;

[0027] Figure 3 The emission spectra of the wafers obtained after processing the crystals obtained in Comparative Examples 1-3 and Examples 1-8 of the present invention under 300nm laser beam excitation are shown; wherein the abscissa is the wavelength and the ordinate is the intensity;

[0028] Figure 4 This is a graph of the maximum luminous intensity of the emission spectrum of the wafer obtained after processing in Example 2-8 of the present invention under the excitation of a 300nm laser beam, wherein the abscissa is the doping concentration and the ordinate is the intensity. DETAILED DESCRIPTION

[0029] The present invention is further described below through the following embodiments. It should be understood that the following embodiments are only used to illustrate the present invention, rather than to limit the present invention.

[0030] The disclosure provides a doped lithium molybdate scintillation crystal material and a preparation method thereof. The material is doped with a sodium-containing compound (Na2CO3, Na2MoO4, or Na2Mo2O7). The preferred doping amounts are as follows: 1 mol% for Na2CO3, 0.8 mol% for Na2MoO4, and 0.6-2 mol% for Na2Mo2O7.

[0031] In the present invention, Na2Mo2O7 is preferably used as a dopant. Compared with other compounds, its doping significantly enhances the luminescence intensity of Li2MoO4 crystals. The optimal doping ratio is 0.8 mol%, under which the luminescence performance of the crystal reaches the best.

[0032] A method for preparing a sodium dimolybdate-doped lithium molybdate crystal according to an embodiment of the present invention comprises the following steps:

[0033] Step 1: synthesize lithium molybdate, sodium molybdate and sodium dimolybdate raw materials by aqueous solution method to prepare sodium carbonate raw material, and mix and grind the ingredients according to the doping amount to obtain crystal growth raw material.

[0034] Step 2: growing the obtained crystal growth raw material in an air atmosphere by a crucible lowering method to obtain a doped lithium molybdate crystal material.

[0035] Preferably, the preparation of the lithium molybdate raw material, i.e., the polycrystalline material, in step 1 comprises:

[0036] Li2CO3 and MoO3 are weighed in a chemical reaction stoichiometric ratio of 1:1; Li2CO3 is dissolved in deionized water, and MoO3 powder is gradually added and stirred for sufficient reaction until the suspension is clear and no bubbles are generated; the suspension is filtered, heated to 60-120°C and lithium molybdate crystals are precipitated, and finally dried at 80-120°C to obtain high-purity lithium molybdate polycrystalline material.

[0037] Preferably, the preparation of the sodium dimolybdate raw material, i.e., the polycrystalline material, in step 1 includes:

[0038] Na2CO3 and MoO3 are weighed in a chemical reaction ratio of 1:2; Na2CO3 is added to deionized water, and MoO3 powder is gradually added and stirred for sufficient reaction until the suspension is clear and no bubbles are generated; the suspension is filtered, heated to 60-120°C to precipitate sodium dimolybdate crystals, and finally dried at 80-120°C to obtain a high-purity sodium dimolybdate polycrystalline material.

[0039] Furthermore, the amount of deionized water is preferably 2 to 4 times, more preferably 3 to 3.5 times, the amount of water required for the corresponding saturated solution of lithium molybdate and sodium dimolybdate after the raw material powders are completely reacted.

[0040] In addition, the dopant is preferably added by mechanical mixing. The purity of the raw materials Li2CO3, MoO3, and Na2CO3 is greater than 99.95%.

[0041] In addition, it is preferred that lithium molybdate crystals be used as seed crystals during crystal growth in step 2.

[0042] And preferably, the crystal growth in step 2 includes the following steps:

[0043] After placing the raw crystal material and seed crystal into a sealed crucible, the temperature was raised to 660-690°C. Once the raw crystal material was completely melted, crystal growth began. The crucible was lowered at a rate of 0.3-0.6 mm / h, and the temperature gradient at the growth interface was 10-15°C / cm. After growth was complete, the crucible was naturally cooled to room temperature to obtain sodium dimolybdate-doped lithium molybdate crystals.

[0044] The following further cites comparative examples and examples to describe the present invention in detail. It should also be understood that the following comparative examples and examples are only used to further illustrate the present invention and cannot be interpreted as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above content of the present invention all fall within the scope of protection of the present invention. The specific process parameters of the following examples are only examples within a suitable range, and those skilled in the art can make selections within a suitable range through the description herein, and are not limited to the specific numerical values exemplified below.

[0045] controlled trials

[0046] Comparative Example 1

[0047] Preparation of pure LMO crystals:

[0048] Step 1: Weigh Li2CO3 and MoO3 in a chemical reaction ratio of 1:1; dissolve Li2CO3 in deionized water, gradually add MoO3 powder, and stir to fully react until the suspension is clear and no bubbles are generated; filter, heat to 100°C to precipitate lithium molybdate crystals, and finally dry at 120°C to obtain high-purity lithium molybdate polycrystalline material.

[0049] Step 2: Use a platinum crucible with a size of 22×22×200mm and a lithium molybdate crystal with a size of 22×22×40mm as a seed crystal, load the lithium molybdate polycrystalline material into the crucible, and then place the crucible in a downconductor. After 15 hours, raise the furnace temperature to 680°C, then keep it warm for 3 hours and gradually raise the downconductor. After all the crystal material in the crucible is melted into a melt, lower the downconductor at a rate of 0.3mm / h to grow the crystal. After the crystal growth is completed, cut off the power supply, cool it naturally to room temperature, take out the crucible, peel the crystal from the crucible, and obtain the lithium molybdate crystal.

[0050] Comparative Example 2

[0051] Preparation of LMO crystal doped with 1 mol% Na2CO3 crystal material. It is particularly noted here that although it is Comparative Example 2, it is still one of the specific embodiments of the present invention and is listed as Comparative Example 2 only for comparison with the doped lithium dimolybdate raw material:

[0052] 1. Prepare high-purity lithium molybdate polycrystalline material according to the method in step 1 of comparative example 1.

[0053] 2. A platinum crucible with a size of 25×25×175 mm and a lithium molybdate crystal with a size of 24×24×50 mm were used as the seed crystal. According to the crucible size, the required lithium molybdate raw material was determined to be 125.72 g, corresponding to a doping amount of 1 mol% Na2CO3 of 0.77 g. The lithium molybdate raw material and Na2CO3 powder were thoroughly mixed and then placed into the platinum crucible together with the seed crystal.

[0054] 3. Place the crucible in the downconductor, raise the furnace temperature to 690°C over 15 hours, then keep it warm for 5 hours while gradually raising the downconductor. After all the crystal material in the crucible has melted into a melt, lower the downconductor at a rate of 0.4 mm / h to allow crystal growth. After the crystal growth is completed, turn off the power supply, cool naturally to room temperature, remove the crucible, and peel the crystal from the crucible to obtain 1 mol% Na2CO3:Li2MoO4 crystals.

[0055] Comparative Example 3:

[0056] Preparation of LMO crystal doped with 0.8 mol% Na2MoO4 crystal material. It is particularly noted here that although it is Comparative Example 3, it is still one of the specific embodiments of the present invention and is listed as Comparative Example 3 only for comparison with the doped lithium dimolybdate raw material:

[0057] 1. Prepare high-purity lithium molybdate polycrystalline material according to the method in step 1 of comparative example 1.

[0058] 2. Synthesis of sodium molybdate:

[0059] Na2CO3 and MoO3 are weighed in a chemical reaction ratio of 1:1; Na2CO3 is added to deionized water, and MoO3 powder is gradually added and stirred for sufficient reaction until the suspension is clear and no bubbles are generated; the suspension is filtered, heated to 80°C to precipitate sodium molybdate crystals, and finally dried at 120°C to obtain high-purity sodium molybdate polycrystalline material.

[0060] 3. Using a platinum crucible measuring 22 × 22 × 200 mm and a lithium molybdate crystal measuring 21 × 21 × 57 mm as a seed crystal, weigh 90.79 g of lithium molybdate raw material and 1.05 g of sodium molybdate (corresponding to a doping level of 0.8 mol%). Thoroughly mix the lithium and sodium molybdate raw materials and place them into the platinum crucible along with the seed crystal.

[0061] 4. Place the crucible in the downconductor, raise the furnace temperature to 680°C over 20 hours, then keep it warm for 4 hours while gradually raising the downconductor. After all the crystal material in the crucible has melted into a melt, lower the downconductor at a rate of 0.3 mm / h to allow crystal growth. After the crystal growth is completed, turn off the power supply, cool naturally to room temperature, remove the crucible, and peel the crystal from the crucible to obtain 0.8 mol% Na2MoO4:Li2MoO4 crystals.

[0062] Example 1

[0063] Step 1, synthesis of lithium molybdate raw materials:

[0064] Li2CO3 and MoO3 were weighed in a 1:1 ratio according to the chemical reaction stoichiometric ratio; Li2CO3 was dissolved in deionized water, and MoO3 powder was gradually added and stirred for sufficient reaction until the suspension was clear and no bubbles were generated; the suspension was filtered, heated to 80°C to precipitate lithium molybdate crystals, and finally dried at 120°C to obtain high-purity lithium molybdate polycrystalline material.

[0065] Step 2, synthesis of sodium dimolybdate raw materials:

[0066] Na2CO3 and MoO3 are weighed according to the chemical reaction stoichiometric ratio of 1:2; Na2CO3 is added to deionized water, and MoO3 powder is gradually added and stirred for sufficient reaction until the suspension is clear and no bubbles are generated; the suspension is filtered, heated to 80°C to precipitate sodium dimolybdate crystals, and finally dried at 110°C to obtain high-purity sodium dimolybdate polycrystalline material.

[0067] Step 3, Crucible Charging:

[0068] Using a platinum crucible measuring 22 × 22 × 200 mm and a 22 × 22 × 50 mm lithium molybdate crystal as a seed crystal, 100 g of lithium molybdate raw material and 1.01 g of sodium dimolybdate (corresponding to a doping level of 0.5 mol%) were weighed. The lithium molybdate raw material and sodium dimolybdate raw material were thoroughly mixed and then placed into the platinum crucible along with the seed crystal.

[0069] Step 4, crystal growth:

[0070] The crucible was placed in the downconductor, and the furnace temperature was raised to 680°C over 15 hours. The temperature was then maintained for 3 hours while the downconductor was gradually raised. After all the crystal material in the crucible was melted into a melt, the downconductor was lowered at a rate of 0.3 mm / h to allow crystal growth. After the crystal growth was completed, the power was turned off, and the mixture was naturally cooled to room temperature. The crucible was removed and the crystal was peeled off from the crucible to obtain 0.5 mol% Na2Mo2O7:Li2MoO4 crystals.

[0071] Example 2

[0072] The steps for synthesizing raw materials are the same as steps 1 and 2 in Example 1;

[0073] A platinum crucible with a size of 25×25×175 mm and a lithium molybdate crystal with a size of 25×25×55 mm were used as the seed crystal. According to the crucible size, the required lithium molybdate raw material was determined to be 115.94 g, corresponding to 1.40 g of sodium dimolybdate with a doping amount of 0.6 mol%. The lithium molybdate raw material and the sodium dimolybdate raw material were fully mixed and then loaded into the platinum crucible together with the seed crystal.

[0074] The crystal growth was the same as step 4 in Example 1, and the crystal was peeled off from the crucible to obtain 0.6 mol% Na2Mo2O7:Li2MoO4 crystals.

[0075] Example 3

[0076] The steps for synthesizing raw materials are the same as steps 1 and 2 in Example 1;

[0077] A platinum crucible with a size of 22×22×200 mm and a lithium molybdate crystal with a size of 21.5×21.5×57 mm was used as a seed crystal. According to the crucible size, the required lithium molybdate raw material was determined to be 115.93 g, corresponding to 1.63 g of sodium dimolybdate with a doping amount of 0.7 mol%. The lithium molybdate raw material and the sodium dimolybdate raw material were fully mixed and then loaded into the platinum crucible together with the seed crystal.

[0078] The crystal growth was the same as step 4 in Example 1, and the crystal was peeled off from the crucible to obtain 0.7 mol% Na2Mo2O7:Li2MoO4 crystals.

[0079] Example 4

[0080] The steps for synthesizing raw materials are the same as steps 1 and 2 in Example 1;

[0081] A platinum crucible with a size of 22×22×200 mm and a lithium molybdate crystal with a size of 22×22×60 mm were used as a seed crystal. According to the crucible size, the required lithium molybdate raw material was determined to be 126.32 g, corresponding to 2.02 g of sodium dimolybdate with a doping amount of 0.8 mol%. The lithium molybdate raw material and the sodium dimolybdate raw material were fully mixed and then loaded into the platinum crucible together with the seed crystal.

[0082] The crystal growth was the same as step 4 in Example 1, and the crystal was peeled off from the crucible to obtain 0.8 mol% Na2Mo2O7:Li2MoO4 crystals.

[0083] Example 5

[0084] The steps for synthesizing raw materials are the same as steps 1 and 2 in Example 1;

[0085] A platinum crucible with a size of 25×25×175 mm and a lithium molybdate crystal with a size of 25×25×60 mm were used as a seed crystal. According to the crucible size, the required lithium molybdate raw material was determined to be 124.25 g, corresponding to 2.25 g of sodium dimolybdate with a doping amount of 0.9 mol%. The lithium molybdate raw material and the sodium dimolybdate raw material were fully mixed and then loaded into the platinum crucible together with the seed crystal.

[0086] The crystal growth was the same as step 4 in Example 1, and the crystal was peeled off from the crucible to obtain 0.9 mol% Na2Mo2O7:Li2MoO4 crystals.

[0087] Example 6

[0088] The steps for synthesizing raw materials are the same as steps 1 and 2 in Example 1;

[0089] A platinum crucible with a size of 25×25×175 mm and a lithium molybdate crystal with a size of 25×25×60 mm were used as the seed crystal. According to the crucible size, the required lithium molybdate raw material was determined to be 105.07 g, corresponding to 2.12 g of sodium dimolybdate with a doping amount of 1 mol%. After the lithium molybdate raw material and the sodium dimolybdate raw material were fully mixed, they were placed in the platinum crucible together with the seed crystal.

[0090] The crystal growth was the same as step 4 in Example 1, and the crystal was peeled off from the crucible to obtain 1 mol% Na2Mo2O7:Li2MoO4 crystals.

[0091] After the grown crystals were ground into powder, XRD analysis was performed, such as Figure 2 shown.

[0092] Example 7

[0093] The steps for synthesizing raw materials are the same as steps 1 and 2 in Example 1;

[0094] A platinum crucible with a size of 25×25×175 mm and a lithium molybdate crystal with a size of 24×24×52 mm were used as the seed crystal. According to the crucible size, the required lithium molybdate raw material was determined to be 130.77 g, corresponding to 2.90 g of sodium dimolybdate with a doping amount of 1.1 mol%. The lithium molybdate raw material and the sodium dimolybdate raw material were fully mixed and then loaded into the platinum crucible together with the seed crystal.

[0095] The crystal growth was the same as step 4 in Example 1. The crystal was peeled off from the crucible to obtain 1.1 mol% Na2Mo2O7:Li2MoO4 crystals.

[0096] Example 8

[0097] The steps for synthesizing raw materials are the same as steps 1 and 2 in Example 1;

[0098] A platinum crucible with a size of 25×25×175 mm and a lithium molybdate crystal with a size of 25×25×55 mm were used as the seed crystal. According to the crucible size, the required lithium molybdate raw material was determined to be 115.15 g, corresponding to 2.78 g of sodium dimolybdate with a doping amount of 1.2 mol%. The lithium molybdate raw material and the sodium dimolybdate raw material were fully mixed and then loaded into the platinum crucible together with the seed crystal.

[0099] The crystal growth was the same as step 4 in Example 1, and the crystal was peeled off from the crucible to obtain 1.2 mol% Na2Mo2O7:Li2MoO4 crystals.

[0100] Depend on Figure 1 As can be seen in the figure, there are photos of crystal blanks with different doping amounts of xNa2Mo2O7:Li2MoO4 (x=0.5-1.2mol%) in Examples 1-8 of the present invention.

[0101] Depend on Figure 2 As can be seen, the 1 mol% Na2Mo2O7:Li2MoO4 crystals grown in Example 5 of the present invention were ground into powder and XRD phase analysis showed that the peak positions of the crystal pattern matched the standard pattern (PDF#22-0906) and there were no other impurity diffraction peaks, indicating that the Li2MoO4 crystals still maintained their original structure after doping and that doping did not introduce any new phases.

[0102] Depend on Figure 3 The results show that under 300nm laser excitation, the luminescence peak of pure Li2MoO4 crystals is located near 425nm. After doping with 1mol% Na2CO3 or 0.8mol% Na2MO4, the luminescence peak shifts to 470nm, increasing the luminescence intensity by approximately 1.3 times and 1.7 times, respectively. However, the luminescence intensity is lower than that of Na2Mo2O7 with the same doping level.

[0103] When doped with 0.5 mol% Na₂Mo₂Oₐ, the luminescence peak matches that of pure Li₂MoO₄ crystals. At a doping concentration of 0.6 mol%, the luminescence peak exhibits a red shift, to around 525 nm. When the doping concentration increases to 0.8 mol%, the luminescence intensity reaches its maximum, while the peak remains unchanged. When the doping concentration exceeds 0.8 mol%, the luminescence peak exhibits a red shift, to around 550 nm.

[0104] Depend on Figure 4 The results show the relationship between Na2Mo2O7 doping concentration and luminescence intensity. When the Na2Mo2O7 doping concentration is 0.6 mol% (the horizontal axis is marked as 6000), the luminescence intensity of the crystal is the weakest. As the doping content increases, the luminescence intensity reaches its peak at a Na2Mo2O7 doping concentration of 0.8 mol%, which is approximately 9 times that of the undoped crystal. When the doping concentration exceeds 0.8 mol%, the luminescence intensity weakens due to quenching of the dopant ion concentration.

[0105] As can be seen from the above, the luminescence performance of Li2MoO4 can be improved by doping Na2Mo2O7 in the embodiment of the present invention. At the same time, the preparation method is simple and easy, which further promotes its practical application in low-temperature crystal calorimeter devices.

[0106] The above is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention should not be considered to be limited to these descriptions. For those skilled in the art of the present invention, without departing from the concept of the present invention, several simple deductions or substitutions can be made, which should be considered to fall within the scope of protection of the present invention.

Claims

1. A doped lithium molybdate scintillation crystal material, characterized in that: The crystalline material is doped with a sodium-containing compound.

2. The doped lithium molybdate scintillation crystal material according to claim 1, characterized in that: The sodium-containing compound is Na2CO3, Na2MoO4 or Na2Mo2O7.

3. The doped lithium molybdate scintillation crystal material according to claim 1, characterized in that: The doping amount of the sodium-containing compound is 0.6-2 mol%.

4. The doped lithium molybdate scintillation crystal material according to claim 3, characterized in that: The sodium-containing compound is Na2CO3, and the doping amount of the Na2CO3 is 1 mol%.

5. The doped lithium molybdate scintillation crystal material according to claim 3, characterized in that: The sodium-containing compound is Na2MoO4, and the doping amount of the Na2MoO4 is 0.8 mol%.

6. The doped lithium molybdate scintillation crystal material according to claim 3, characterized in that: The sodium-containing compound is Na2Mo2O7, and the doping amount of the Na2Mo2O7 is 0.7-1.1 mol%.

7. A method for preparing the doped lithium molybdate scintillation crystal material according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1: preparing lithium molybdate and sodium-containing compound raw materials; Step 2: According to the required doping amount, the lithium molybdate raw material and the sodium compound raw material are mixed and ground to obtain a crystal growth raw material; Step 3: growing the obtained crystal growth raw material in an air atmosphere by a crucible drop method to obtain a doped lithium molybdate scintillation crystal material.

8. The method for preparing the doped lithium molybdate scintillation crystal material according to claim 7, wherein: In the step 1, lithium molybdate and part of the sodium-containing compound raw materials are synthesized by an aqueous solution method.

9. The method for preparing the doped lithium molybdate scintillation crystal material according to claim 7, wherein: The mixing and grinding in step 2 is carried out by mechanical mixing.

10. The method for preparing the doped lithium molybdate scintillation crystal material according to claim 7, characterized in that: The crystal growth in step 3 uses lithium molybdate crystals as seed crystals.

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