Evaporation method for directional growth of long rod-like KDP crystal and device thereof

Abstract

The application belongs to the technical field of crystal growth, and particularly relates to an evaporation method directional growth device and method of long rod-shaped KDP crystal. The evaporation crystal growth device with built-in growth solution is fixed in a water bath heating and insulation device, a solvent evaporation pool is installed on a crystal seed fixing seat through a crystal growth groove, a fluid channel connecting the crystal seed fixing seat and the solvent evaporation pool is left in the crystal growth groove, the fluid channel is a long rod-shaped cavity, and heating and insulation ends of two sets of temperature control subsystems are located on the outside of the evaporation crystal growth device and have different installation heights. The application provides a new idea for obtaining long rod-shaped directional KDP crystal, uses a self-designed evaporation crystal growth device, performs directional growth of the crystal based on the solvent evaporation method, has high raw material utilization rate, fast growth speed, can effectively increase the stability of the solution and reduce the possibility of growth failure, can avoid mechanical cutting, and reduces the damage probability of the crystal.

Description

Technical Field

[0001] This invention belongs to the field of crystal growth technology, specifically relating to an evaporation-based directional growth apparatus and method for long rod-shaped KDP-type crystals. Background Technology

[0002] Potassium dihydrogen phosphate (KH₂PO₄, abbreviated as KDP) crystal is a high-performance nonlinear optical material with advantages such as a large nonlinear optical coefficient, a wide transmission band, high resistance to laser-induced damage, and ease of growing large-diameter single crystals, making it widely used in the laser field. KDP crystal is currently the only nonlinear optical crystal suitable for inertial confinement fusion (ICF) engineering. The main growth method is the point-seed rapid growth method, which involves placing a point-like seed crystal in a solution of growth raw materials and cooling it to a supersaturated state. The dissolved raw materials gradually crystallize and precipitate on the surface of the point-like seed crystal, causing it to grow continuously and obtain a larger crystal. Due to room temperature and the properties of the material itself, the cooling range is usually chosen between 55℃ and 25℃. However, because the raw materials still have high solubility at room temperature, the solute utilization rate in this process is only 32.9%. Meanwhile, due to lattice distortion near the interface between the cone and cylinder faces of the crystal, the performance of the transmitted light beam is affected, leading to a decrease in crystal utilization. To avoid the appearance of the cone-cylinder interface, a rod-shaped seed crystal in the Z-direction is usually placed between two parallel plates, allowing the crystal to extend only in the cylinder direction, thus avoiding the appearance of the interface. The traditional method for obtaining rod-shaped KDP single crystals involves mechanically cutting large-sized bulk KDP crystals grown using a cooling method. However, mechanical equipment such as wire cutting machines can easily cause irreversible damage to the crystal due to heat accumulation during post-processing, severely affecting the success rate of obtaining rod-shaped KDP single crystals. Furthermore, bulk KDP crystals grown using the cooling method have very low raw material utilization, significant disadvantages in terms of growth container volume and floor space, and are expensive.

[0003] Therefore, designing an evaporation-based directional growth device for long rod-shaped KDP crystals that avoids post-mechanical processing can solve the problem of seed source in large-size KDP crystals, thereby greatly improving the quality of large-size KDP crystals and having considerable industrial production value and economic benefits. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides an evaporation-based directional growth apparatus and method for long rod-shaped KDP crystals. The method uses a self-designed evaporation crystal grower for directional crystal growth, which can obtain long rod-shaped KDP crystals along a specific direction at a faster speed with a material utilization rate several times higher than that of traditional cooling growth methods. Furthermore, it completely avoids subsequent mechanical processing and greatly reduces the floor space occupied by the crystal grower.

[0005] The technical solution adopted by this invention to solve its technical problem is as follows: an evaporation-based directional growth apparatus for long rod-shaped KDP-type crystals, comprising: an evaporation crystal grower and a water bath heating and insulation device, wherein the evaporation crystal grower, which contains a growth solution, is fixedly placed in the water bath heating and insulation device; the bottom of the evaporation crystal grower is a seed crystal holder, and the upper end is provided with a solvent evaporation pool, wherein the solvent evaporation pool is installed on the seed crystal holder through a crystal growth tank, and a fluid channel is provided in the crystal growth tank to connect the seed crystal holder and the solvent evaporation pool, wherein the fluid channel is a long rod-shaped cavity; the water bath heating and insulation device comprises: two sets of temperature control subsystems, wherein the heating and insulation ends of the temperature control subsystems are located outside the evaporation crystal grower and are installed at different heights.

[0006] Preferably, the heating and insulation end of one temperature control subsystem is placed outside the solvent evaporation tank, and the heating and insulation end of the other temperature control subsystem is placed outside the crystal growth tank.

[0007] Preferably, the solvent evaporation tank is funnel-shaped.

[0008] Preferably, the solvent evaporation tank has an opening at the top and is equipped with an evaporation rate control cover. The top of the solvent evaporation tank is also covered with a microporous semi-permeable membrane, and the evaporation rate control cover is located above the microporous semi-permeable membrane.

[0009] Preferably, the solvent evaporation pool is tilted at an angle of 20°-30°; the micropore diameter of the microporous semipermeable membrane is less than 100 nanometers.

[0010] Preferably, the temperature control subsystem includes: an annular heater and a matching thermocouple, wherein the annular heater is installed by a fixed bracket standing in the water bath heating and insulation device, and the annular heater moves up and down along the crystal growth tank.

[0011] Preferably, it further includes: a crystal grower row support, wherein the evaporation crystal growers are arranged side by side on the crystal grower row support, and the crystal grower row support is fixedly erected in the water bath heating and insulation device.

[0012] Preferably, in the crystal growth tank, a stainless steel shell is fixedly installed on the plexiglass cover plate, and a U-shaped groove is placed between the plexiglass cover plate and the stainless steel shell.

[0013] A method for directional growth of long rod-shaped KDP-type crystals by evaporation, comprising the following steps:

[0014] S1. Preparation stage: First, place the seed crystals in the seed fixing groove at the bottom of the evaporator crystal grower. Then, fix the assembled and sealed evaporator crystal grower in the water bath heating and insulation device and start the water bath heating and insulation device for preheating.

[0015] S2. During the growth stage, growth solution is injected into the solvent evaporation tank. Two sets of temperature control subsystems are set to heat and maintain the temperature. The temperature control subsystem located outside the crystal growth tank has a heating and maintaining temperature that is 1-2°C higher than the temperature corresponding to the saturated solution of the crystal material. The other temperature control subsystem has a heating and maintaining temperature that is more than 6°C higher than the temperature control subsystem located outside the crystal growth tank. The opening of the evaporation rate control cover is adjusted to make the replenishment and consumption rate of the supersaturation of the growth solution consistent.

[0016] S3. In the completion stage, after the crystal grows to the expected size, two temperature control subsystems are set up to slowly cool down to the ambient temperature, and the long rod-shaped KDP crystal grown along a specific direction is taken out.

[0017] Preferably, during the growth stage, the method further includes: adjusting the height of the heater of the temperature control subsystem located outside the crystal growth tank according to the crystal height, so that it is located 10-15 cm above the crystal.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] 1. The directional growth device in this application is equipped with a restricted crystal growth tank, which provides external conditions conducive to one-dimensional crystal growth, avoids subsequent mechanical processing, and greatly reduces the floor space occupied by the crystal grower.

[0020] 2. The directional growth apparatus in this application is equipped with a dual temperature control system, which facilitates system temperature control, ensures a smooth and steady transition of the solution, and promotes the directional and stable growth of crystals.

[0021] 3. A ring heater is used to adjust the height and temperature along the crystal growth groove according to the crystal growth height, which improves the quality of long rod-shaped oriented KDP crystals.

[0022] 4. A microporous semi-permeable membrane and an evaporation rate control cover are installed on the solvent evaporation tank to increase the stability of the solution;

[0023] 5. Using solvent evaporation-based directional growth can increase raw material utilization to nearly 100%;

[0024] In summary, this application provides a novel approach to obtaining long, rod-shaped oriented KDP crystals. Employing a self-designed evaporation crystallizer, the oriented growth of crystals is achieved through solvent evaporation, enabling stable, controllable, and efficient growth of long, rod-shaped KDP crystals. This approach boasts high raw material utilization, rapid growth rate, and effectively increases solution stability, reducing the likelihood of growth failure. Furthermore, it avoids mechanical cutting, lowering the chance of crystal damage. The structure is simple, the equipment is small, and the production cost is low. The equipment operates under static conditions, exhibiting high stability and ease of operation. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the evaporation-based directional growth apparatus for long rod-shaped KDP crystals in this invention.

[0026] Figure 2 This is a schematic diagram of the cross-section of the crystal growth tank.

[0027] Figure 3 This is a top view of the evaporation rate control cover.

[0028] Figure 4 This is a schematic diagram of the installation and use of the crystal growth device row support of the present invention.

[0029] Figure 5 This is a graph showing the crystal transmittance test results of samples prepared using the equipment described in this application and those prepared using conventional methods.

[0030] Figure 6 The graph shows the test results of the second harmonic conversion efficiency of the sample prepared by the equipment of this application and the traditional sample preparation.

[0031] Figure 7 The graph shows the test results of laser-induced damage threshold for samples prepared by the equipment in this application and those prepared by conventional methods.

[0032] Figure 8 This is a graph comparing the raw material utilization rates of the method in this application with those of traditional methods.

[0033] In the diagram: 1. Evaporation rate control cover, 2. Solvent evaporation tank, 3. Crystal growth tank, 4. Seed holder, 5. Growth solution, 6. Microporous semi-permeable membrane, 7. Evaporation crystal grower, 8. Acrylic glass cover, 9. Stainless steel shell, 10. U-shaped trough, 11. Row of supports, 12. Water bath liquid, 13. Seed crystal, 14. High temperature insulation device, 15. Low temperature insulation device, 16. High temperature heating equipment, 17. Low temperature heating equipment, 18. High temperature probe, 19. Low temperature probe, 20. Control system, 21. Fixing bracket.

[0034] Figure 5-7 In the figures, novel sample preparation 1, 2, and 3 are samples prepared using the equipment of this application; conventional sample preparation 1, 2, and 3 are samples prepared using conventional equipment. Figure 8 The novel method is the method described in this application. Detailed Implementation

[0035] To facilitate understanding of the present invention, it will be described in more detail below with reference to the accompanying drawings and specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described in this specification. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of the present invention.

[0036] Example 1: Combination Figure 1 An evaporation-based directional growth apparatus for long rod-shaped KDP-type crystals is described, comprising: an evaporation crystal grower 7 and a water bath heating and insulation device. The evaporation crystal grower 7, containing a growth solution, is fixedly positioned within the water bath heating and insulation device. The evaporation crystal grower 7 consists of three parts: an upper funnel-shaped solvent evaporation tank 2, a middle detachable long rod-shaped crystal growth tank 3, and a bottom seed holder 4, vertically connected and sealed with silicone rubber sealant. A fluid channel is provided within the crystal growth tank 3, connecting the seed holder 4 to the solvent evaporation tank 2. The various parts of the evaporation crystal grower 7 are connected and fixed with silicone rubber sealant, ensuring no leakage of the internal solution while allowing for disassembly and separation of the parts, which is beneficial for obtaining long rod-shaped crystals. The use of the seed holder 4 at the bottom of the restricted crystal growth tank 3 ensures the use of specific tangential seed crystals and provides a certain degree of protection against deformation of the seed crystals. The water bath heating and insulation device includes two temperature control subsystems. The heating and insulation end of one temperature control subsystem is located outside the solvent evaporation tank 2, and the heating and insulation end of the other temperature control subsystem is located outside the crystal growth tank 3. The water bath heating and insulation device controls the solvent evaporation tank 2 and the confined crystal growth tank 3 respectively through the upper and lower temperature control systems using water as the medium.

[0037] In one embodiment, the solvent evaporation tank 2 is tilted at an angle of 20°-30° to facilitate the transport of supersaturation generated by solvent evaporation to the crystal surface.

[0038] In one embodiment, the solvent evaporation tank 2 has an opening at its upper end and is fitted with a microporous semi-permeable membrane 6. The micropore diameter of the microporous semi-permeable membrane 6 is less than 100 nanometers, which can ensure the evaporation and escape of solvent molecules while avoiding disturbance of the growth solution by the external environment, thereby improving the stability of the growth process. An evaporation rate control cover 1 is placed on top of the microporous semi-permeable membrane 6. Figure 3 As shown, the evaporation rate control cover 1 has a structure for adjusting the size of the opening, used to control the evaporation rate of the solvent. The opening area of ​​the evaporation rate control cover 1 can be adjusted in real time according to the amount of raw material consumed in the solution during crystal growth, making the evaporation rate controllable, and rationally configuring the replenishment and consumption rates of supersaturation to ensure that the growth driving force inside the solution is within a relatively stable range, effectively improving the crystal growth rate and quality uniformity.

[0039] In one embodiment, the temperature control subsystem includes: an annular heater and a matching thermocouple. Water, which serves as a heat-conducting and heat-insulating medium, is present on the outside of the evaporator crystal growth tank 7. An annular heater and a matching thermocouple are provided on the outside of the detachable long rod-shaped crystal growth tank 3 for monitoring and controlling the temperature of the water bath.

[0040] In one embodiment, an annular heater that can move up and down is located outside the evaporator crystal grower 7. The temperature is controlled by the matching thermocouple, and both the set temperature and height are within a certain preset range to ensure the stability of the growth driving force in the crystal growth environment. The preset temperature range is set with reference to the temperature setting corresponding to the saturated solution of the crystal material; the preset height range is 10-16 cm above the actual crystal growth height.

[0041] In one embodiment, combined Figure 4 The understanding also includes: a row of crystal growers, wherein the evaporation crystal growers 7 can be placed side by side in the row of crystal growers at the same horizontal level, and are heated and kept in the same water bath. The temperature is uniformly controlled by the heat transfer medium water, which further optimizes the complexity of the device and reduces production costs.

[0042] In one embodiment, combined Figure 2 It is understood that the detachable long rod-shaped crystal growth tank 3 can be disassembled into an acrylic U-shaped tank 10, an acrylic cover plate 8, and a stainless steel shell 9. The acrylic cover plate 8 is 5mm thick, and the stainless steel shell 9 is 5mm thick. They are fixedly connected by stainless steel screws. The acrylic U-shaped tank 10 is 1mm thick and is placed in the cavity formed by the acrylic cover plate 8 and the stainless steel shell 9. This ensures that the morphology of the crystal inside is restricted during the growth process, and the geometric shape of the container does not change. It also facilitates the demolding of the acrylic U-shaped tank 10 and the long rod-shaped crystal inside.

[0043] The crystal directional growth method:

[0044] A seed crystal with a specific orientation is placed in the seed crystal fixing groove at the bottom of the evaporation crystal grower 7, and fixed to the internal cavity of the plexiglass U-shaped groove 10 in the detachable long rod-shaped crystal growth groove 3 by silicone rubber sealant. It is then connected to the funnel-shaped solvent evaporation pool 2 by silicone rubber sealant. The top is covered with a microporous semi-permeable membrane 6 and an evaporation rate control cover 1, and is fixed on the crystal grower support 11 and placed in a water bath heating and insulation device.

[0045] A saturated solution of crystal material is injected into the solvent evaporation tank 2. The evaporation rate is adjusted according to the actual mass of raw materials consumed in the crystal growth, and the opening size of the cover 1 is controlled. The water bath heating and heat preservation device is turned on, and the two temperature control systems are adjusted according to the initial concentration of the solution. At the same time, the movable ring heater is moved to the target height and gradually rises as the crystal height increases. Generally, the height of the movable ring heater is 10-15cm above the crystal.

[0046] As the solvent evaporation tank 2 evaporates, the solution inside gradually decreases until it is completely consumed, causing the height of the seed crystals with a specific orientation inside the evaporation crystal grower 7 to continuously increase. The growth space of the seed crystals is restricted in a specific direction until they grow into rod-shaped single crystals with a large aspect ratio. The array-type electric heating temperature control device ensures that the growth driving force gradient near the crystal is stable and controllable. After the growth is completed, the detachable long rod-shaped crystal growth tank 3 is disassembled, and the organic glass U-shaped tank 10 and the rod-shaped crystals therein can be separated.

[0047] Example 2: Combination Figure 1-4 An evaporation-based directional growth apparatus for long rod-shaped KDP-type crystals is described, comprising: an evaporation rate control cover 1, a funnel-shaped solvent evaporation tank 2, a detachable long rod-shaped crystal growth tank 3, a seed holder 4, and a growth solution 5 inside the seed holder 4. The seed holder 4 is connected to the funnel-shaped solvent evaporation tank 2 via the detachable long rod-shaped crystal growth tank 3. After the opening of the solvent evaporation tank 2 is covered with a microporous semi-permeable membrane 6, the evaporation rate control cover 1 is installed, forming an evaporation crystal grower 7. The detachable long rod-shaped crystal growth tank 3 is composed of an plexiglass cover plate 8 and a stainless steel shell 9, with an plexiglass U-shaped groove 10 fixed inside. The evaporation crystal grower 7 can be fixed on a crystal growth support 11 and placed in a water bath liquid 12.

[0048] Working Principle: When using this invention, firstly, the plexiglass cover plate 8 and the stainless steel shell 9 are connected and fixed with stainless steel screws. The plexiglass U-shaped groove 10 is placed in the inner long rod-shaped cavity. The seed crystal 13 for growth is placed on the seed crystal fixing seat 4 and fixed in the inner cavity of the plexiglass U-shaped groove 10 with silicone rubber sealant. On the other side, the funnel-shaped solvent evaporation pool 2 is connected with silicone rubber sealant. The microporous semi-permeable membrane 6 is covered at the opening on the larger side of the funnel-shaped solvent evaporation pool 2, and the evaporation rate control cover 1 is pressed tightly on it. The evaporation crystal grower 7 is fixed in the water bath liquid 12. The high-temperature heat preservation device 14 is placed at a higher vertical position, and the low-temperature heat preservation device 15 is placed at a lower vertical position. The resulting temperature difference can achieve supersaturation. The heating method of the water bath liquid 12 can make the temperature and solute distribution of the growth solution 5 more uniform, and at the same time, the precipitated solute causes the seed crystal 13 to begin to grow.

[0049] The above technical solution also includes a temperature control system; the temperature control system is composed of the high-temperature insulation device 14 and the low-temperature insulation device 15 located in different positions. The two insulation devices are specifically composed of a high-temperature heating device 16 and a low-temperature heating device 17, a high-temperature probe 18 and a low-temperature probe 19, and a control system 20; the high-temperature heating device 16 and the low-temperature heating device 17 are specifically heating rods immersed in the water bath liquid 12; the high-temperature probe 18 and the low-temperature probe 19 are temperature sensors immersed in the water bath liquid 12; the low-temperature heating device 17 and the low-temperature probe 19 can move in the longitudinal direction with the help of the fixed bracket 21, and the heating rods and temperature sensors are all connected to the control system 20 through wires.

[0050] Working principle: The high-temperature probe 18 located in the water bath liquid 12 can stably obtain the current temperature parameters of the water bath liquid 12, providing a reference for subsequent crystal growth temperature adjustment; the high-temperature heating device 16 can control the temperature in the water bath liquid 12, providing stable heat for solvent evaporation, while the low-temperature probe 19 can detect the temperature parameters near the growth surface of the seed crystal 13 in real time. By moving the low-temperature heating device 17, the temperature distribution of the growth solution 5 along the longitudinal direction can be adjusted to achieve precise temperature control, thereby timely adjusting the supersaturation gradient of the solution between the seed crystal 13 and the funnel-shaped solvent evaporation pool 2, and improving the growth quality of the seed crystal 13.

[0051] In the above technical solution, a method for growing long rod-shaped single crystal materials along a specific direction based on solvent evaporation includes the following specific steps:

[0052] Step 1: Prepare a growth solution 5 with a mass fraction of 23.7% by mixing KH2PO4 powder raw material (analytical grade) and high-purity deionized water (resistivity >17.5MΩ / cm) as solvent. Filter the growth solution 5 using commercially available 0.1μm and 0.05μm polyethersulfone resin microporous filter membranes and a double-layer flat plate filter, and perform overheat treatment at 51°C for at least 24 hours.

[0053] Step 2: Place the seed crystal 13 on the seed crystal holder 4, connect the fixed evaporation rate control cover 1, the funnel-shaped solvent evaporation pool 2, and the detachable long rod-shaped crystal growth tank 3 to assemble the evaporation crystal grower 7, place it in the crystal growth support 11, and use the water bath liquid 12, high temperature heating equipment 16 and low temperature heating equipment 17 to preheat the evaporation crystal grower 7 until the seed crystal 13 is preheated to a stable state at 37°C and maintained for at least 24 hours;

[0054] Step 3: Transfer the growth solution 5 to the evaporation crystallizer 7, adjust the high temperature heating equipment to 16 to 42°C and the low temperature heating equipment to 17 to 36°C so that the growth solution 5 in the evaporation crystallizer 7 has a certain degree of supersaturation and obtains growth driving force. Adjust the evaporation rate to control the opening size of the cover 1 so that the replenishment and consumption rate of supersaturation are consistent. The seed crystal 13 grows in a one-dimensional controllable and stable manner in the organic glass U-shaped groove A10 at a certain speed.

[0055] Step 4: Record and calculate the height of seed crystal 13. Adjust the height of the heater in the low-temperature insulation device 15 according to the actual height of seed crystal 13, so that it is always 13cm above the crystal. Calculate the actual supersaturation consumption based on the volume of crystal growth, and adjust the set temperature of the high-temperature insulation device 14 accordingly to make the supersaturation replenishment and consumption rate consistent. The crystal growth rate should be controlled at 10mm / day.

[0056] Step 5: After the crystal grows to the expected size, the high-temperature insulation device 14 and the low-temperature insulation device 15 are set to cool down slowly at a rate of 0.1℃ / h. After cooling to ambient temperature, the silicone rubber sealant between the funnel-shaped solvent evaporation tank 2, the detachable long rod-shaped crystal growth tank 3, and the seed crystal holder 4 is removed. The stainless steel screws of the plexiglass cover plate 8 and the stainless steel shell 9 are also removed, separating the plexiglass U-shaped tank 10 containing the long rod-shaped KDP crystal. Finally, a 10mm*10mm*400mm long rod-shaped KDP crystal grown in a specific direction is obtained.

[0057] Performance Testing: Long rod-shaped KDP crystal samples prepared using the apparatus and method of this application were compared with rod-shaped KDP crystal samples obtained by cutting bulk crystals grown using conventional equipment. Tests were conducted on crystal transmittance, second harmonic conversion efficiency, and laser-induced damage threshold. Results are as follows: Figure 5-7 As shown. Figure 5-7 In the diagram, samples 1, 2, and 3 prepared using the novel sample preparation method are those prepared using the apparatus described in this application; samples 1, 2, and 3 prepared using conventional sample preparation methods are those prepared using conventional equipment. The raw material utilization rate was calculated for each sample, and the results are as follows: Figure 8 As shown.

[0058] The transmittance of the crystal was tested using a SHIMADZU 3600iPLUS UV-VIS-FIR spectrophotometer. At a wavelength of 1064 nm, the sample prepared by the device of this application had the same excellent optical homogeneity as the sample prepared by conventional equipment.

[0059] The second harmonic conversion efficiency and laser-induced damage threshold were tested using a CONTINUUM Powerlite DLS 8000 pulsed laser with a 10ns pulse of 1064nm. The beam diameter used in the test was 8mm, and the single pulse energy was 828.7mJ. The second harmonic conversion efficiency of the crystal prepared by the device in this application is comparable to that of the sample prepared by conventional equipment. However, under the 1-on-1 laser-induced damage threshold test, the crystal prepared by the device in this application shows a slight improvement compared to the conventional method.

[0060] Therefore, the novel device in this application can increase the utilization rate of raw materials to nearly 100% while ensuring that the optical quality of the product is not compromised, and obtain long rod-shaped KDP single crystals along a certain direction at a relatively fast speed. The device is extremely small, thereby greatly reducing costs, increasing yield, and shortening the growth cycle.

[0061] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. A method for oriented growth of long rod-like KDP-like crystals by evaporation, characterized in that, The steps are as follows: S1, preparation stage, first put the point seed crystal in the crystal seed fixing groove at the bottom of the evaporation growth device, then fix the assembled and sealed evaporation growth device in the water bath heating and insulation device, start the water bath heating and insulation device, and preheat; S2, growth stage, inject the growth solution into the solvent evaporation pool, set the heating and insulation temperature of the two sets of temperature control subsystems respectively, the heating and insulation temperature of the temperature control subsystem located outside the crystal growth groove is 1-2℃ higher than the corresponding temperature of the saturated solution of the crystal material, the heating and insulation temperature of the other temperature control subsystem is more than 6℃ higher than the heating and insulation temperature of the temperature control subsystem located outside the crystal growth groove, and adjust the opening degree of the evaporation speed control cover to make the supplement and consumption rate of the supersaturation degree of the growth solution consistent; S3, completion stage, after the crystal grows to the expected size, set the two sets of temperature control subsystems to slowly cool to ambient temperature, and take out the long rod-shaped KDP crystal grown in a specific direction; The evaporation method directional growth device used in the evaporation method directional growth method comprises an evaporation growth device and a water bath heating and insulation device, and the evaporation growth device containing growth solution is fixed in the water bath heating and insulation device; The bottom of the evaporation growth device is a crystal seed fixing seat, the upper end is provided with a solvent evaporation pool, the solvent evaporation pool is installed on the crystal seed fixing seat through a crystal growth groove, a fluid channel connecting the crystal seed fixing seat and the solvent evaporation pool is left in the crystal growth groove, the fluid channel is a long rod-shaped cavity, the long rod-shaped cavity is arranged in a vertical direction, the upper end of the funnel-shaped solvent evaporation pool is open and is provided with an evaporation speed control cover, the upper end of the solvent evaporation pool is also covered with a microporous semi-permeable membrane, and the evaporation speed control cover is located above the microporous semi-permeable membrane; The water bath heating and insulation device comprises two sets of temperature control subsystems, and the heating and insulation ends of the temperature control subsystems are located outside the evaporation growth device and are installed at different heights; The temperature control subsystem comprises a ring-shaped heater; One heating and insulation end of one temperature control subsystem is located outside the solvent evaporation pool, and the heating and insulation end of the other temperature control subsystem is located outside the crystal growth groove, and the ring-shaped heater moves up and down along the crystal growth groove; In the growth stage, it also comprises adjusting the height of the heater of the temperature control subsystem located outside the crystal growth groove so that it is located 10-15 cm above the crystal.

2. The method for oriented growth of long rod-like KDP-like crystals by evaporation method according to claim 1, characterized in that, The inclination angle of the solvent evaporation pool is 20°-30°, and the membrane micropore diameter of the microporous semi-permeable membrane is less than 100 nanometers.

3. The method for oriented growth of long rod-like KDP-like crystals by evaporation according to any one of claims 1-2, characterized in that, The temperature control subsystem comprises a matched thermocouple, and one ring-shaped heater is installed through a fixing support standing in the water bath heating and insulation device.

4. The method for oriented growth of long rod-like KDP-type crystals by evaporation according to claim 3, characterized in that, It also comprises: The evaporation growth devices are arranged side by side on the crystal growth device rowing support, and the crystal growth device rowing support is fixed in the water bath heating and insulation device.

5. The method of claim 3, wherein the long rod-like KDP crystal is grown by evaporation method. In the crystal growth groove, a stainless steel shell is fixedly installed on the organic glass cover plate, and a U-shaped groove is arranged between the organic glass cover plate and the stainless steel shell.

Images