A low-temperature seed crystal induction growth method of salicylamide ultrafast scintillation crystal

Abstract

A low-temperature seed-induced growth method for salicylamide ultrafast scintillation crystals is disclosed, involving ultrafast scintillation crystals and their low-temperature seed-induced growth method. This method aims to solve the technical problems of uncontrollable growth rate, sensitivity to environmental fluctuations, easy generation of microscopic defects within the crystal, and poor dimensional regularity in existing organic crystal scintillators. The method comprises: 1. Obtaining high-quality seed crystals through isothermal volatilization; 2. Preparing a saturated growth solution; 3. Precise temperature equilibration treatment; 4. Seed crystal-induced slow volatilization growth. The salicylamide single crystals prepared by this method reach a size of 15mm × 9mm × 1.5mm. Its photo-induced decay time is approximately 5.93 ns. 137 The radioactive decay time under Cs excitation is approximately 2.82 ns, which can be used in the field of radiation detection.

Description

Technical Field

[0001] This invention belongs to the field of artificial crystal growth and radiation detection technology, specifically relating to ultrafast scintillation crystals and their low-temperature seed crystal-induced growth method. Background Technology

[0002] With the rapid development of high-energy physics experiments, ultrafast nuclear medicine imaging (such as TOF-PET), and nuclear safety monitoring, almost stringent requirements have been placed on the temporal resolution of radiation detectors. As the core conversion material of the detector, the decay time of the scintillator is a key factor affecting the system's temporal resolution.

[0003] Currently used inorganic scintillators possess high effective atomic numbers and photoelectric absorption cross sections, exhibiting excellent stopping capabilities for high-energy radiation. However, they often suffer from limitations such as long decay times (typically >10 ns), high-temperature dependence on growth processes (e.g., Czochralski method, crucible descent method), and high fabrication costs. In contrast, the luminescence of organic scintillators primarily originates from the deexcitation of singlet excitons, typically exhibiting intrinsic decay times on the order of nanoseconds, demonstrating excellent time response characteristics. Furthermore, they are widely available, have low fabrication costs, and are easily fabricated into large-area detectors, showcasing irreplaceable advantages in the fields of fast neutron detection and ultrafast radiation imaging.

[0004] Among numerous organic light-emitting materials, organic crystals with excited-state intramolecular proton transfer (ESIPT) properties have attracted considerable attention. ESIPT molecules, represented by salicylamide, undergo an ultrafast proton transfer process after excitation, producing ketoluminescence with a large Stokes shift. This significant redshift effectively suppresses the self-absorption effect of the crystal, not only enhancing light output but, more importantly, its unique molecular energy level transition mechanism endows it with ultrafast decay characteristics, making it an ideal building block for preparing ultrafast response scintillators. However, the preparation of high-quality, large-size organic crystals still faces significant challenges. Currently, commonly used laboratory growth methods include room-temperature natural evaporation and gradient cooling. However, in actual growth processes, room-temperature evaporation is highly susceptible to fluctuations in ambient temperature and humidity, leading to uncontrollable solvent evaporation rates. This unstable kinetic process not only results in lengthy crystal growth cycles but also leads to the formation of microscopic defects, dislocations, or solvent inclusions within the crystal. Gradient cooling methods inevitably introduce temperature gradients within the solution system during growth. For structurally fragile organic molecular crystals, the uneven thermal field distribution caused by these gradients can generate significant internal stresses, easily leading to lattice distortion or even crystal cracking. Simultaneously, convective fluctuations induced by temperature differences can interfere with the orderly stacking of solute molecules at the interface, making it difficult to guarantee consistent crystal quality. Therefore, exploring a growth method that can precisely control growth kinetics, reduce structural defects, and maintain the inherent rapid decay characteristics of salicylamide is of great significance for promoting the practical application of high-performance organic crystal scintillators. Summary of the Invention

[0005] This invention aims to address the technical problems of existing organic crystal scintillators, including uncontrollable growth rate, sensitivity to environmental fluctuations, susceptibility to microscopic defects (such as inclusions and dislocations) within the crystal, and poor dimensional regularity. It provides a low-temperature seed-induced growth method for salicylamide ultrafast scintillators. Addressing the extremely high temporal resolution requirements of ultrafast scintillators, this invention utilizes a growth method based on precise supersaturation control and a low-temperature seed-induced mechanism to significantly suppress defect formation and maintain the inherent fast decay characteristics of salicylamide.

[0006] The low-temperature seed crystal-induced growth method for salicylamide ultrafast scintillation crystals of the present invention is carried out according to the following steps:

[0007] I. Obtaining high-quality seed crystals by isothermal volatilization: Salicylate raw material is added to an organic solvent and stirred until completely dissolved. The solution is then filtered through an organic filter membrane with a pore size of 0.22 μm to remove insoluble microparticles. The clarified filtrate is transferred to a crystallization container and crystal nuclei are induced to form and millimeter-sized single crystals are precipitated as seed crystals by isothermal volatilization at a constant temperature of 30°C.

[0008] 2. Preparation of saturated growth solution: At room temperature, according to the saturated solubility of salicylamide in an organic solvent at the growth temperature, add salicylamide to the organic solvent, stir until the raw material is completely dissolved, and then filter through a 0.22μm pore size filter membrane to obtain a clear saturated growth solution; the growth temperature is 10~20℃.

[0009] III. Precision Temperature Equilibrium Treatment: The saturated growth solution obtained in Step II is sealed and placed together with the seed crystal obtained in Step I in a constant temperature environment at the growth temperature for 12-24 hours to achieve static equilibrium. This step aims to achieve complete thermodynamic equilibrium between the solution system and the seed crystal, eliminating the temperature gradient between them. Its core function is to prevent the seed crystal from undergoing autolysis due to thermal shock upon immersion in the solution, or from inducing a large number of disordered parasitic crystal nuclei due to a sudden change in local supersaturation on the seed crystal surface, thereby ensuring the directional and orderly layer-by-layer growth of solute molecules on the seed crystal surface.

[0010] IV. Seed Crystal-Induced Slow Evaporation Growth: The seed crystal is placed in a saturated growth solution, and the container mouth is tightly sealed with aluminum foil. A microhole with a diameter of 0.5~0.8mm is punched in the center of the aluminum foil with a 1mL syringe needle to control the extremely slow evaporation of the solvent. The container is placed in a constant temperature incubator at the growth temperature with temperature fluctuations strictly controlled within ±0.2℃ for 10~14 days to obtain salicylamide ultrafast scintillation crystals. This step, through precise thermodynamic and kinetic synergistic control, yields salicylamide single crystals with a size of 15mm×9mm×1.5mm.

[0011] Furthermore, the stirring described in step one is performed under magnetic stirring at 500-600 rpm to ensure complete dissolution.

[0012] Furthermore, the organic solvent mentioned in step one is ethyl acetate, and the solution is prepared at a ratio of 3.8g of salicylamide to 30ml of ethyl acetate; or the organic solvent mentioned in step one is methanol, and the solution is prepared at a ratio of 4.9g of salicylamide to 30ml of methanol.

[0013] Furthermore, the stirring described in step two is performed under magnetic stirring at 500-600 rpm to ensure complete dissolution.

[0014] Furthermore, in step two, the growth temperature is 15°C, the organic solvent is ethyl acetate, and the saturated growth solution is prepared at a ratio of 1.8g salicylamide dissolved in every 20ml of ethyl acetate.

[0015] Furthermore, in step two, the growth temperature is 15°C, the organic solvent is methanol, and the saturated growth solution is prepared at a ratio of 2.1g of salicylamide dissolved in 20ml of methanol.

[0016] Furthermore, in step three, the constant temperature holding time is 18-20 hours to ensure that the seed crystal interior and the entire solution precisely reach the preset growth temperature equilibrium point.

[0017] Furthermore, in step four, the temperature of the constant temperature chamber is precisely controlled within the range of ±0.1℃ of the growth temperature. This extremely precise temperature control, combined with the micropore-controlled extremely low solvent evaporation rate, ensures that the crystal growth process remains in a low-supersaturation state within the metastable region for an extended period, thereby establishing a controlled growth kinetic environment.

[0018] The advantages of this invention are as follows:

[0019] 1. Excellent Time Response Characteristics: The salicylate crystal prepared in this invention utilizes the excited-state intramolecular proton transfer (ESIPT) mechanism, exhibiting excellent time response characteristics. Experiments have shown that its photo-induced decay time is approximately 5.93 ns. 137 The radioactive decay time under Cs excitation is approximately 2.82 ns, which meets the requirements of the radiation detection field for high-performance response materials.

[0020] 2. Excellent crystal quality and controlled large-size growth: By employing a low-temperature environment of 10~20℃ combined with seed crystal induction technology, the interference of thermal motion of solvent molecules is effectively reduced, overcoming the limitations of uncontrollable nucleation and small crystal thickness in traditional room-temperature spontaneous nucleation methods. The prepared crystals can reach sizes of 15mm×9mm×1.5mm, and have extremely high optical transparency, with no obvious internal defects such as dislocations or solvent inclusions, successfully achieving controlled growth of large-size, high-thickness organic single crystals.

[0021] 3. High stability, consistency, and universality of the process: This invention introduces "preset temperature equilibrium" technology and micropore evaporation rate control, solving the problems of chemical dissolution and physical damage when the seed crystal is first placed in the solution, ensuring the orderly accumulation of solute molecules at the seed crystal interface. This process has been validated in different polar solvent systems such as ethyl acetate and methanol, demonstrating good universality and greatly improving the success rate and batch consistency of high-quality organic single crystal growth, which is beneficial for large-scale preparation. Attached Figure Description

[0022] Figure 1 The graph shows the saturated solubility of salicylamide in ethyl acetate and ethanol.

[0023] Figure 2 The images show the seed crystal obtained in step one of Example 1 and the salicylamide ultrafast scintillation crystal obtained in step four; where a is the seed crystal and b is the salicylamide ultrafast scintillation crystal.

[0024] Figure 3 X-ray diffraction pattern of the salicylamide ultrafast scintillation crystal prepared in Example 1;

[0025] Figure 4 The photoluminescence emission spectrum of the salicylamide crystal prepared in Example 1 is shown below;

[0026] Figure 5 This is a graph showing the photo-induced decay time of the salicylamide crystals prepared in Example 1.

[0027] Figure 6 The salicylamide crystals prepared in Example 1 were in 137 Radiation-induced decay curves under Cs radioactive source excitation;

[0028] Figure 7 A photograph of the salicylamide ultrafast scintillation crystal prepared in Example 2;

[0029] Figure 8 This is a graph showing the photo-induced decay time of the salicylamide crystals prepared in Example 2.

[0030] Figure 9 A photograph of the salicylamide ultrafast scintillation crystal prepared in Example 3;

[0031] Figure 10 This is a graph showing the photo-induced decay time of the salicylamide crystals prepared in Example 3.

[0032] Figure 11 A photograph of the salicylamide ultrafast scintillation crystal prepared in Example 4;

[0033] Figure 12 The graph shows the photo-induced decay time of the salicylamide crystals prepared in Example 4. Detailed Implementation

[0034] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and embodiments, but the present invention is not limited to the scope of the embodiments described.

[0035] Example 1: The low-temperature seed crystal-induced growth method for salicylamide ultrafast scintillation crystals in this example is carried out according to the following steps:

[0036] I. Obtaining high-quality seed crystals by isothermal evaporation method: Accurately weigh 3.8g of salicylamide raw material and add it to 30ml of ethyl acetate solvent. Stir thoroughly on a magnetic stirrer at 500 rpm until the raw material is completely dissolved to obtain a solution. Filter the solution using an organic filter membrane with a pore size of 0.22μm. Transfer the clear filtrate to a sample bottle and place it in a 30℃ isothermal incubator for isothermal evaporation. After millimeter-sized single crystals precipitate, select crystals with smooth surfaces and regular shapes as seed crystals.

[0037] II. Preparation of saturated growth solution: According to... Figure 1 The saturated solubility curve of salicylamide in ethyl acetate shows that the saturated solubility of salicylamide in ethyl acetate at a growth temperature of 15℃ is 9.0 g / 100 ml. At room temperature, 1.8 g of salicylamide was weighed and added to 20 ml of ethyl acetate. A magnetic stirrer was turned on and stirred continuously at 500 rpm until the raw material was completely dissolved. The solution was filtered using a 0.22 μm pore size filter membrane, and the clear filtrate was transferred to a sample bottle and sealed for later use. This clear filtrate is the saturated growth solution.

[0038] 3. Precision temperature equilibration treatment: Place the sealed sample bottle containing the saturated growth solution and the selected seed crystals into a constant temperature incubator at 15℃. The temperature fluctuation of the constant temperature incubator is controlled within ±0.1℃. Let it stand and maintain the temperature for 20 hours. This step aims to make the thermodynamic state inside the solution system completely consistent with that of the seed crystals, so as to prevent the seed crystals from undergoing violent dissolution on the surface or inducing the generation of stray crystal nuclei due to temperature difference when they are put into the solution.

[0039] IV. Seed crystal-induced slow evaporation growth: The seed crystal was placed in the center of the saturated growth solution, and the mouth of the container was tightly sealed with aluminum foil. A microhole with a diameter of 0.5 mm was punched in the center of the aluminum foil with a 1 mL syringe needle to control the extremely slow evaporation of the solvent. The container was placed in a constant temperature incubator at 15℃ with temperature fluctuations strictly controlled within ±0.1℃ for 10 days to obtain salicylamide ultrafast scintillation crystals.

[0040] The images of the seed crystal obtained in step one and the salicylate ultrafast scintillation crystal obtained in step four of Example 1 are shown below. Figure 2 As shown, a is a seed crystal, and b is a salicylate ultrafast scintillation crystal. Figure 2 As can be seen, the seed crystal surface is smooth, and the size of the salicylamide ultrafast scintillation crystal is 15mm×9mm×1.5mm, which is a high-quality salicylamide organic single crystal.

[0041] The X-ray diffraction pattern of the salicylamide ultrafast scintillation crystal prepared in Example 1 is shown below. Figure 3 As shown, from Figure 3 It can be seen that the crystal diffraction peaks are sharp and free of impurities, proving that the crystals prepared by this method have extremely high crystallinity and purity.

[0042] Figure 4 The image shows the photoluminescence emission spectrum of the salicylamide crystals prepared in Example 1. Figure 4 It can be seen that the emission peak of the salicylamide crystal is located at 430 nm.

[0043] Figure 5 The image shows the photo-degradation time curve of the salicylamide crystal prepared in Example 1. The photo-degradation time is about 5.93 ns, which shows that its lifetime is extremely short and it has excellent time response characteristics.

[0044] Figure 6 The salicylamide crystals prepared in Example 1 were in 137 The radiation-induced attenuation curve under Cs radioactive source excitation, from Figure 6 It can be seen that, 137 The Cs radiation-induced decay time is approximately 2.82 ns.

[0045] Example 2: The low-temperature seed crystal-induced growth method for salicylamide ultrafast scintillation crystals in this example is carried out according to the following steps:

[0046] I. Obtaining high-quality seed crystals by isothermal evaporation method: 4.9g of salicylamide raw material was added to 30ml of methanol and stirred thoroughly at 500 rpm on a magnetic stirrer until the raw material was completely dissolved to obtain a solution; the solution was filtered using an organic filter membrane with a pore size of 0.22μm; the clear filtrate was transferred to a sample vial and placed in a 30℃ isothermal incubator for isothermal evaporation. After millimeter-sized single crystals were precipitated, crystals with smooth surfaces and regular shapes were selected as seed crystals;

[0047] II. Preparation of saturated growth solution: According to... Figure 1 The saturated solubility curve of salicylamide in methanol shows that the saturated solubility of salicylamide in methanol at 15℃ is 10.5 g / 100 ml. At room temperature, 2.1 g of salicylamide was weighed and added to 20 ml of methanol. A magnetic stirrer was turned on and stirred continuously at 500 rpm until the raw material was completely dissolved. The solution was filtered using a 0.22 μm pore size filter membrane, and the clear filtrate was transferred to a sample bottle and sealed for later use. This clear filtrate is the saturated growth solution.

[0048] 3. Precision temperature equilibration treatment: Place the sealed sample bottle containing the saturated growth solution and the selected seed crystals into a constant temperature incubator at 15℃. The temperature fluctuation of the constant temperature incubator is controlled within ±0.1℃. Let it stand and maintain the temperature for 20 hours. This step aims to make the thermodynamic state inside the solution system completely consistent with that of the seed crystals, so as to prevent the seed crystals from undergoing violent dissolution on the surface or inducing the generation of stray crystal nuclei due to temperature difference when they are put into the solution.

[0049] IV. Seed crystal-induced slow evaporation growth: The seed crystal was placed in the center of the saturated growth solution, and the mouth of the container was tightly sealed with aluminum foil. A microhole with a diameter of 0.5 mm was punched in the center of the aluminum foil with a 1 mL syringe needle to control the extremely slow evaporation of the solvent. The container was placed in a constant temperature incubator at 15℃ with temperature fluctuations strictly controlled within ±0.1℃ for 10 days to obtain salicylamide ultrafast scintillation crystals.

[0050] The image of the salicylamide ultrafast scintillation crystal prepared in Example 2 is shown below. Figure 7 As shown, from Figure 7 As can be seen, the crystal has a well-preserved macroscopic morphology and high transparency. Test results show that its scintillation performance is highly consistent with the salicylamide ultrafast scintillation crystal prepared in Example 1, demonstrating the good universality of this process for different organic solvent systems.

[0051] Example 3: This example differs from Example 1 in that the growth temperature is controlled at 20℃. The specific preparation method is as follows:

[0052] I. Obtaining high-quality seed crystals by isothermal volatilization: This step is the same as in Example 1;

[0053] II. Preparation of saturated growth solution: According to... Figure 1 The saturated solubility curve of salicylamide in ethyl acetate shows that the saturated solubility of salicylamide in ethyl acetate at a growth temperature of 20℃ is 10.0 g / 100 ml. At room temperature, 2 g of salicylamide was weighed and added to 20 ml of ethyl acetate. A magnetic stirrer was turned on and stirred continuously at 500 rpm until the raw material was completely dissolved. The solution was filtered using a 0.22 μm pore size filter membrane, and the clear filtrate was transferred to a sample bottle and sealed for later use. This clear filtrate is the saturated growth solution.

[0054] 3. Precision temperature equilibration treatment: Place the sealed sample bottle containing the saturated growth solution and the selected seed crystals into a constant temperature incubator at 20℃. The temperature fluctuation of the constant temperature incubator is controlled within ±0.1℃. Let it stand and maintain the temperature equilibration for 20 hours.

[0055] IV. Seed crystal-induced slow volatilization growth: The seed crystal was placed in the center of the saturated growth solution, and the mouth of the container was tightly sealed with aluminum foil. A microhole with a diameter of 0.5 mm was punched in the center of the aluminum foil with a 1 mL syringe needle. The container was placed in a constant temperature incubator at 20℃ with temperature fluctuations strictly controlled within ±0.1℃ for 10 days to obtain salicylamide ultrafast scintillation crystals.

[0056] The image of the salicylamide ultrafast scintillation crystal prepared in Example 3 is shown below. Figure 9 As shown, Figure 10 The graph shows the photo-degradation time of the salicylamide crystals prepared in Example 3. The test results show that the photo-degradation time is about 6.01 ns, which proves that the process has good universality for different preset growth temperatures.

[0057] Example 4: This example differs from Example 1 in that the growth temperature is controlled at 10℃. The specific preparation method is as follows:

[0058] I. Obtaining high-quality seed crystals by isothermal volatilization: This step is the same as in Example 1;

[0059] II. Preparation of saturated growth solution: According to... Figure 1 The saturated solubility curve of salicylamide in ethyl acetate shows that the saturated solubility of salicylamide in ethyl acetate at a growth temperature of 10℃ is 8.2 g / 100 ml. At room temperature, 1.64 g of salicylamide was weighed and added to 20 ml of ethyl acetate. A magnetic stirrer was turned on and stirred continuously at 500 rpm until the raw material was completely dissolved. The solution was filtered using a 0.22 μm pore size filter membrane, and the clear filtrate was transferred to a sample bottle and sealed for later use. This clear filtrate is the saturated growth solution.

[0060] 3. Precision temperature equilibration treatment: Place the sealed sample bottle containing the saturated growth solution and the selected seed crystals into a constant temperature incubator at 10℃. The temperature fluctuation of the constant temperature incubator is controlled within ±0.1℃. Let it stand and maintain the temperature equilibration for 20 hours.

[0061] IV. Seed crystal-induced slow volatilization growth: The seed crystal was placed in the center of the saturated growth solution, and the mouth of the container was tightly sealed with aluminum foil. A microhole with a diameter of 0.5 mm was punched in the center of the aluminum foil with a 1 mL syringe needle. The container was placed in a constant temperature incubator at 10℃ with temperature fluctuations strictly controlled within ±0.1℃ for 10 days to obtain salicylamide ultrafast scintillation crystals.

[0062] The photograph of the salicylamide ultrafast scintillation crystal prepared in Example 4 is shown below. Figure 11 As shown, from Figure 11 It can be seen that the crystal has a well-preserved macroscopic morphology and high transparency. Figure 12 The graph shows the photo-degradation time of the salicylamide crystals prepared in Example 4. The test results show that the photo-degradation time is about 5.98 ns, which proves that the process has good universality for different preset growth temperatures.

[0063] This invention effectively suppresses microscopic defects and structural disorder in the crystal caused by ambient temperature fluctuations and the thermal motion of solvent molecules by implementing precise temperature control and seed crystal induced growth at a low temperature environment of 10~20℃, thus ensuring the intrinsic ultrafast response characteristics of salicylamide crystals based on the excited-state intramolecular proton transfer (ESIPT) mechanism. Compared with traditional natural volatilization and gradient cooling methods, this invention successfully prepares large-size organic single crystals with high thickness and complete crystallization through deep synergistic control of thermodynamic equilibrium and growth kinetics, providing an ideal material basis for the practical application of ultrafast scintillation detectors.

Claims

1. A method for low-temperature seed-induced growth of salicylamide ultrafast scintillation crystals, characterized in that, This method is performed in the following steps: I. Obtaining high-quality seed crystals by isothermal volatilization: Salicylate raw material is added to an organic solvent and stirred until completely dissolved. The solution is then filtered through an organic filter membrane with a pore size of 0.22 μm to remove insoluble microparticles. The clarified filtrate is transferred to a crystallization container and crystal nuclei are induced to form and millimeter-sized single crystals are precipitated as seed crystals by isothermal volatilization at a constant temperature of 30°C.

2. Preparation of saturated growth solution: At room temperature, according to the saturated solubility of salicylamide in an organic solvent at the growth temperature, add salicylamide to the organic solvent, stir until the raw material is completely dissolved, and then filter through a 0.22μm pore size filter membrane to obtain a clear saturated growth solution; the growth temperature is 10~20℃.

3. Precision temperature equilibration treatment: Seal the saturated growth solution obtained in step 2, and place it together with the seed crystal obtained in step 1 in a constant temperature environment at the growth temperature for static equilibration and heat preservation for 12~24 hours. IV. Seed crystal-induced slow evaporation growth: The seed crystal is placed in a saturated growth solution, and the container mouth is tightly sealed with aluminum foil. A microhole with a diameter of 0.5~0.8mm is punched in the center of the aluminum foil with a 1mL syringe needle to control the extremely slow evaporation of the solvent. The container is placed in a constant temperature incubator at the growth temperature and the temperature fluctuation is strictly controlled within ±0.2℃ for 10~14 days to obtain salicylamide ultrafast scintillation crystals.

2. The low-temperature seed crystal-induced growth method for salicylamide ultrafast scintillation crystal according to claim 1, characterized in that, The stirring described in step one is performed under magnetic stirring at 500-600 rpm to completely dissolve the substances.

3. The low-temperature seed crystal-induced growth method for salicylamide ultrafast scintillation crystal according to claim 1 or 2, characterized in that, The organic solvent mentioned in step one is ethyl acetate, and the solution is prepared by dissolving 3.8g of salicylamide in every 30ml of ethyl acetate; or the organic solvent mentioned in step one is methanol, and the solution is prepared by dissolving 4.9g of salicylamide in every 30ml of methanol.

4. The low-temperature seed crystal-induced growth method for salicylamide ultrafast scintillation crystal according to claim 1 or 2, characterized in that, The stirring described in step two involves magnetic stirring at 500-600 rpm to ensure complete dissolution.

5. A method for low-temperature seed-induced growth of salicylamide ultrafast scintillation crystals according to claim 1 or 2, characterized in that, In step two, the growth temperature is 15°C, the organic solvent is ethyl acetate, and the saturated growth solution is prepared at a ratio of 1.8g salicylamide dissolved in every 20ml of ethyl acetate.

6. The low-temperature seed crystal-induced growth method for salicylamide ultrafast scintillation crystal according to claim 1 or 2, characterized in that, In step two, the growth temperature is 15°C, the organic solvent is methanol, and the saturated growth solution is prepared at a ratio of 2.1g of salicylamide dissolved in 20ml of methanol.

7. A method for low-temperature seed-induced growth of salicylamide ultrafast scintillation crystals according to claim 1 or 2, characterized in that, In step three, the heat preservation time is 18 to 20 hours.

8. A method for low-temperature seed-induced growth of salicylamide ultrafast scintillation crystals according to claim 1 or 2, characterized in that, In step four, the temperature of the constant temperature incubator is precisely controlled within the range of ±0.1℃ of the growth temperature.

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