阅读说明：本技术 一种用于液氮冷却多层膜的热疲劳测试的试验装置 (Test device for thermal fatigue test of liquid nitrogen cooling multilayer film ) 是由 梁柯林 徐中民 秦宏亮 何健 于 2020-12-28 设计创作，主要内容包括：本发明涉及一种用于液氮冷却多层膜的热疲劳测试的试验装置,包括真空室,其内设有冷却块和精密运动滑台,所述精密运动滑台上设有热沉和用于固定多层膜的夹持器,所述冷却块和热沉为可分离触接,所述热沉与夹持器之间设有传热导线,所述夹持器远离所述热沉的一面上设置有电加热片；电子枪,设置于真空室外,其枪管伸入所述真空室内并与所述真空室固定连接；液氮循环主机,与所述冷却块相连通而形成循环冷却系统；温控仪,与所述夹持器上的电加热片连接。本发明的试验装置通过循环试验模拟多层膜受热变形的低周疲劳过程,为有限元分析结果提供试验验证条件,对多层膜光学元件液氮冷却热疲劳研究有重要意义。(The invention relates to a test device for thermal fatigue test of a liquid nitrogen cooling multilayer film, which comprises a vacuum chamber, wherein a cooling block and a precision motion sliding table are arranged in the vacuum chamber, a heat sink and a clamp holder for fixing the multilayer film are arranged on the precision motion sliding table, the cooling block and the heat sink are in separable contact, a heat transfer lead is arranged between the heat sink and the clamp holder, and an electric heating sheet is arranged on one surface of the clamp holder, which is far away from the heat sink; the electron gun is arranged outside the vacuum chamber, and a gun tube of the electron gun extends into the vacuum chamber and is fixedly connected with the vacuum chamber; the liquid nitrogen circulating host is communicated with the cooling block to form a circulating cooling system; and the temperature controller is connected with the electric heating sheet on the clamp holder. The test device provided by the invention simulates the low-cycle fatigue process of the multilayer film under thermal deformation through a cycle test, provides test verification conditions for finite element analysis results, and has important significance for liquid nitrogen cooling thermal fatigue research of the multilayer film optical element.)

1. A test device for thermal fatigue testing of liquid nitrogen cooled multilayer films, characterized by comprising:

the vacuum chamber is internally provided with a cooling block and a precision motion sliding table, the precision motion sliding table is provided with a heat sink and a holder for fixing the multilayer film, the cooling block and the heat sink are in separable contact, a heat transfer wire is arranged between the heat sink and the holder, and one surface of the holder far away from the heat sink is provided with an electric heating sheet;

the electron gun is arranged outside the vacuum chamber, and a gun tube of the electron gun extends into the vacuum chamber and is fixedly connected with the vacuum chamber;

the liquid nitrogen circulating host is communicated with the cooling block to form a circulating cooling system;

and the temperature controller is connected with the electric heating sheet on the clamp holder.

2. The testing device for the thermal fatigue test of the liquid nitrogen cooling multilayer film according to claim 1, further comprising a temperature sensor and a strain gauge for monitoring the temperature and the stress-strain state of the multilayer film in real time.

3. The apparatus for testing thermal fatigue of liquid nitrogen-cooled multilayer film according to claim 1, wherein said heat transfer wire is disposed on both sides of said heat sink and holder.

4. The testing apparatus for thermal fatigue testing of liquid nitrogen-cooled multilayer films according to claim 1, wherein the heat transfer wire is a copper braid.

5. The testing device for the thermal fatigue test of the liquid nitrogen-cooled multilayer film according to claim 1, wherein a groove is provided on the holder, and the electric heating wire is fixed in the groove.

6. The experimental device for the thermal fatigue test of the liquid nitrogen-cooled multilayer film according to claim 5, wherein the heating wire in the electric heating sheet is arranged in a zigzag shape.

7. The testing device for the thermal fatigue test of the liquid nitrogen cooling multilayer film according to claim 1, wherein the cooling block is provided with two through holes which are arranged in parallel, a liquid nitrogen cooling pipe is arranged in each through hole, and two ends of each liquid nitrogen cooling pipe are respectively communicated with the liquid nitrogen circulating main machine.

8. The testing device for the thermal fatigue test of the liquid nitrogen cooling multilayer film as claimed in claim 1, wherein a protrusion is arranged on one surface of the heat sink close to the cooling block, and a contact hole matched with the protrusion is arranged on the cooling block.

9. The apparatus for testing thermal fatigue of liquid nitrogen-cooled multilayer film according to claim 8, wherein the heat sink is integrally formed with the projection.

10. The testing device for the thermal fatigue test of the liquid nitrogen cooling multilayer film according to claim 1, wherein a heat insulation ceramic base is arranged on the precision motion sliding table, and the heat sink and the holder are fixed on the heat insulation ceramic base.

11. The testing device for the thermal fatigue test of the liquid nitrogen cooling multilayer film according to claim 1, wherein an adjusting base plate is arranged in the vacuum chamber, and the precision motion sliding table is fixed on the adjusting base plate.

12. The experimental device for the thermal fatigue test of the liquid nitrogen cooling multilayer film as claimed in claim 1, wherein indium sheets are padded at the contact part of the cooling block and the heat sink and the contact part of the heat transfer lead and the heat sink and the clamper.

13. The testing device for the thermal fatigue test of the liquid nitrogen cooling multilayer film according to claim 2, wherein a driving device connected with the precision motion sliding table is arranged in the vacuum chamber.

14. The testing device for the thermal fatigue test of the liquid nitrogen-cooled multilayer film according to claim 13, wherein a PLC control system is arranged outside the vacuum chamber and is electrically connected with the electron gun, the temperature controller, the temperature sensor, the liquid nitrogen circulation host and the driving device respectively.

Technical Field

The invention relates to the field of synchrotron radiation, in particular to a test device for a thermal fatigue test of a liquid nitrogen cooling multilayer film.

Background

The insert light source in the third generation synchrotron radiation device generates very high energy X-rays, and the optical element illuminated thereby is thermally deformed due to thermal load, reducing the performance of the beam, including beam size, divergence angle, and photon flux. In order to reduce thermal deformation, two modes of water cooling and liquid nitrogen cooling are provided, and for the fourth generation light source represented by Beijing light source which has high power density and is upgraded in the future, the water cooling mode adopted by part of line stations cannot meet the requirement, and the liquid nitrogen cooling is needed to enable the surface shape of the optical element to meet the requirement. The X-ray multilayer film element is characterized in that a film layer made of two materials is plated on a substrate with a certain surface type at intervals, a material thin layer with a larger refractive index is used as a scattering layer to realize scattering of X-rays, and a material thin layer with a smaller refractive index is used as a spacing layer to support the scattering layer, so that the X-ray multilayer film element can be regarded as an artificial one-dimensional photonic crystal. Compared with common silicon crystal, the multilayer film has a larger bandwidth and a higher reflectivity than a crystal monochromator, and the light transmission efficiency of the multilayer film is 2 orders of magnitude higher than that of the crystal monochromator. Under the conditions of liquid nitrogen cooling and high-power density X-ray irradiation, the multilayer film element generates great thermal stress in the film layer when the temperature of the element changes due to the difference of the thermal expansion coefficients of the film layer material and the substrate material. The thermal stress causes surface deformation of the element surface on one hand and film cracking, element damage and even failure on the other hand.

At present, a fatigue testing device for a sample under a liquid nitrogen cooling condition is mainly formed by additionally arranging a liquid nitrogen tank on a fatigue testing machine, liquid nitrogen provides a low-temperature environment through an injection environment box, liquid nitrogen cannot be recycled and is wasted a lot, the aimed sample is mainly made of metal and alloy materials thereof, and fatigue testing cannot be performed on an optical element.

Disclosure of Invention

The invention aims to provide a test device for testing thermal fatigue of a liquid nitrogen cooling multilayer film, so as to test and research the thermal fatigue and long-term operation reliability of a multilayer film optical element.

The invention provides a test device for thermal fatigue test of a liquid nitrogen cooling multilayer film, which comprises:

the vacuum chamber is internally provided with a cooling block and a precision motion sliding table, the precision motion sliding table is provided with a heat sink and a holder for fixing the multilayer film, the cooling block and the heat sink are in separable contact, a heat transfer wire is arranged between the heat sink and the holder, and one surface of the holder far away from the heat sink is provided with an electric heating sheet;

the electron gun is arranged outside the vacuum chamber, and a gun tube of the electron gun extends into the vacuum chamber and is fixedly connected with the vacuum chamber;

the liquid nitrogen circulating host is communicated with the cooling block to form a circulating cooling system;

and the temperature controller is connected with the electric heating sheet on the clamp holder.

Further, the device also comprises a temperature sensor and a strain gauge, which are respectively used for monitoring the temperature and the stress strain state of the multilayer film in real time.

Further, the heat transfer wire is arranged on two sides of the heat sink and the clamp.

Further, the heat transfer wire is a copper braid.

Furthermore, a groove is formed in the holder, and the electric heating wire is fixed in the groove.

Furthermore, the heating wires in the electric heating sheet are arranged in a zigzag shape.

Furthermore, the cooling block is provided with two through holes which are arranged in parallel, liquid nitrogen cooling pipes are arranged in the through holes, and two ends of each liquid nitrogen cooling pipe are respectively communicated with the liquid nitrogen circulating host machine.

Furthermore, a protrusion is arranged on one surface of the heat sink close to the cooling block, and a contact hole matched with the protrusion is arranged on the cooling block.

Further, the heat sink is integrally formed with the protrusion.

Furthermore, a heat insulation ceramic base is arranged on the precision motion sliding table, and the heat sink and the holder are fixed on the heat insulation ceramic base.

Furthermore, an adjusting base plate is arranged in the vacuum chamber, and the precision motion sliding table is fixed on the adjusting base plate.

Further, indium sheets are padded at the contact positions of the cooling block and the heat sink and at the contact positions of the heat transfer lead, the heat sink and the clamper.

Furthermore, a driving device connected with the precision motion sliding table is arranged in the vacuum chamber.

Furthermore, a PLC control system is arranged outside the vacuum chamber and is respectively and electrically connected with the electron gun, the temperature control instrument, the temperature sensor, the liquid nitrogen circulating host and the driving device.

According to the test device for the thermal fatigue test of the liquid nitrogen cooling multilayer film, the structure that the heat sink and the cooling block can be in detachable contact is arranged to simulate the thermal load loading process, so that the periodic fatigue process from normal temperature-cooling-loading-unloading-cooling-normal temperature is realized, the working state of the multilayer film of the light source line station is simulated in a real off-line manner, and the reliability of the test result is ensured; by connecting the heat sink and the holder on both sides by using a copper braid, the influence on the deformation of the multilayer film can be minimized; the fatigue test process can be effectively accelerated by arranging the electric heating sheet to assist in temperature return; the PLC automatic control can reduce the influence of human factors on the test. The test device for the thermal fatigue test of the liquid nitrogen cooling multilayer film simulates the low-cycle fatigue process of the multilayer film under thermal deformation through a cycle test, provides test verification conditions for finite element analysis results, has significance for the research of liquid nitrogen cooling thermal fatigue of the multilayer film optical element under a high-power density light beam, can be used for predicting the fatigue life of the multilayer film, and can be used for researching the thermal fatigue analysis of other liquid nitrogen cooling optical elements after being irradiated by X rays.

Drawings

FIG. 1 is a schematic overall structure diagram of a test device for thermal fatigue testing of a liquid nitrogen-cooled multilayer film according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a component located within a vacuum chamber according to an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of a clamp according to an embodiment of the present invention;

fig. 4 is a schematic diagram showing a positional relationship among the multilayer film, the temperature sensor, and the strain gauge;

FIG. 5 is a schematic diagram of the vacuum chamber, the cooling block and the liquid nitrogen cooling tube structure provided by the embodiment of the invention;

FIG. 6 is a schematic structural diagram of a cooling block provided in an embodiment of the present invention;

fig. 7 is a schematic structural diagram of a heat sink provided in an embodiment of the present invention;

fig. 8 is a schematic structural diagram of an insulating ceramic base under a heat sink according to an embodiment of the present invention.

Detailed Description

The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

As shown in fig. 1, an embodiment of the present invention provides a test apparatus for thermal fatigue testing of a liquid nitrogen cooled multilayer film, including a vacuum chamber 1, and an electron gun 2, a liquid nitrogen circulation host 14 and a temperature controller 15 which are disposed outside the vacuum chamber 1, where the vacuum chamber 1 is a circular cavity with a diameter of 450mm, and is provided therein with a cooling block 7 and a precision motion sliding table 4, the precision motion sliding table 4 is provided with a heat sink 6 and a holder 5 for fixing the multilayer film 12, and the precision motion sliding table 4 can move in a direction away from or close to the cooling block 7, and can be selected from any one of the existing models, for example, in this embodiment, a precision motion sliding table with a model of MVXA05A-R102 is adopted, and the heat sink 6 and the cooling block 7 can be separately contacted under the driving of the precision; one side of the precision motion sliding table 4 is connected with a driving device 3, such as a servo motor, for driving the motion of the precision motion sliding table 4; the side of the clamper 5 far away from the heat sink 6 is provided with an electric heating sheet 11 for heating a multilayer film 12; a window (not shown in the figure) can be opened on the peripheral wall of the vacuum chamber 1, the barrel of the electron gun 2 extends into the vacuum chamber 1 through the window and is arranged on the window through a flange, the window is used for simulating the X ray of a synchrotron radiation light source in the test process, 100mA beam current can be generated at 8keV, the barrel of the electron gun 7 is aligned to the multilayer film 12, and the emitted electron beam can be conveniently struck on the multilayer film 12; the cooling block 7 is communicated with a liquid nitrogen circulation main machine 14 to form a circulation cooling system, and when the heat sink 6 is in contact with the cooling block 7, the multi-layer film 12 can be cooled through heat transfer among the cooling block 7, the heat sink 6 and the clamp 5; the temperature controller 15 is electrically connected to the electric heating plate 11 on the holder 5, and in this embodiment, the temperature controller 15 is of the type Lake Shore 336.

As shown in fig. 2, the cooling block 7, the heat sink 6 and the holder 5 may be arranged in sequence and opposite to each other, and the heat conducting wires 9 are respectively connected to both sides of the heat sink 6 and the holder 5, and heat is conducted between the heat sink 6 and the holder 5 through the heat conducting wires 9, for example, the heat conducting wires 9 may be copper braids, the copper braids are connected with the heat sink 6 and the holder 5 through two hexagon socket head cap screws on each side, and the connected copper braids still have a certain length redundancy to reduce the transmission of deformation and vibration.

The multilayer film 12 is fixed on the side of the holder 5 far away from the heat sink 6, in the embodiment, the multilayer film 12 adopts a silicon substrate, a Ru/C alternating period multilayer film, the period number is 100, the interlayer spacing is 2.5nm, the size of the silicon substrate is 60mm by 30mm by 10mm, the crystal surface error of the multilayer film is less than 1urad (RMS), and the surface roughness error is less than 0.3nm (RMS). The electrical heating sheet 11 may be disposed between the silicon substrate of the multilayer film 12 and the holder 5.

Specifically, as shown in fig. 3, a groove 51 may be provided on the holder 5, the electric heating sheet 11 and the multilayer film 12 are both located in the groove 51 (in order to show the electric heating sheet 11, the multilayer film 12 is not shown in fig. 3), and the heating wire of the electric heating sheet 11 is zigzag-shaped to increase the contact area with the multilayer film 12, thereby improving the heating efficiency. The multilayer film 12 is fixed in the groove 51 through two hexagon socket head cap screws, two mirror clamps 17 are arranged outside the groove 51 and fixed on the clamp holder 5 through screws, the multilayer film 12 is prevented from toppling over to play a role in shielding, and actually, the mirror clamps 17 and the multilayer film 12 are not in contact with each other, so that the multilayer film 12 is less subjected to external deformation.

As shown in fig. 4, the testing apparatus further includes a temperature sensor 19 and a strain gauge 20, for example, a probe of the temperature sensor 19 may be placed on a silicon substrate of the multilayer film 12 for real-time monitoring of the temperature of the multilayer film 12, and two strain gauges 20 may be provided for measuring and recording the stress-strain state of the multilayer film 12, and one strain gauge 20 may be placed on each of the multilayer films at a position close to the light spot range 121 of the electron beam, so that the measured data may be more realistic, and the strain gauges 20 may not be directly irradiated by the electron beam, and may be protected.

As shown in fig. 5 and 6, the cooling block 7 may be configured as an H-shaped copper plate, which has two through holes (not shown) along the length direction of the H-shape, a U-shaped liquid nitrogen cooling pipe 8 passes through the two through holes and is welded to the cooling block 7, and two ends of the U-shaped liquid nitrogen cooling pipe 8 respectively pass through the outer circumferential wall of the vacuum chamber 1 and then are communicated with the liquid nitrogen circulation main unit 14.

As shown in fig. 7, the heat sink 6 may be configured as a rectangular plate, on which a copper protrusion 61 is disposed, and correspondingly, as shown in fig. 6, a contact hole 71 is disposed on the cooling block 7 to match with the protrusion 61, and after the protrusion 61 is inserted into the contact hole 71, the heat sink 6 is attached to the cooling block 7 for transferring heat. Preferably, the heat sink 6 is integrally formed with the protrusion 61.

With continued reference to fig. 2, a thermally insulating ceramic base 10 may also be provided on the precision motion slide 4, below the heat sink 6 and the holder 5, respectively, the heat sink 6 and the holder 5 being fixed on the thermally insulating ceramic base 10 to reduce heat transfer between the heat sink 6, the holder 5 and the precision motion slide 4. In a possible embodiment, as shown in fig. 3, the heat-insulating ceramic base 10 located below the holder 5 is two small square pieces arranged at intervals, and both the small square pieces are fixedly connected with the holder 5 and the precision motion sliding table 4 through screws; as shown in fig. 8, the heat insulating ceramic base 10 located below the heat sink 6 is in a shape of a "convex", the heat sink 6 is fixed to the boss by screws, and the two sides of the heat insulating ceramic base 10, which are not convex, are fixedly connected to the precision motion sliding table 4 by screws.

As shown in fig. 2, an adjusting shim plate 18 can be further arranged in the vacuum chamber 1, and is fixed in the vacuum chamber 1 through four line-shaped countersunk head screws, the precision motion sliding table 4 is fixed on the adjusting shim plate 18 through four line-shaped countersunk head screws, and the adjusting shim plate 18 plays a role in supporting and adjusting the height of the precision motion sliding table 4.

As shown in fig. 1, the testing apparatus of the present embodiment may further include a Programmable Logic Controller (PLC)13 located outside the vacuum chamber 1, and controlling the electron gun 2, the temperature controller 15, the liquid nitrogen circulation host 14, the temperature sensor 19, the driving device 3, and the like, so as to realize automatic control of the whole testing apparatus and reduce the influence of human factors.

The cooling block 7, the heat sink 6 and the holder 5 can be made of oxygen-free copper materials to improve the heat transfer efficiency.

Indium sheets may be padded at each heat exchange contact, e.g. at the circumference of the protrusion 61, at the contact of the cooling block 7 and the heat sink 6, at the contact of the copper braid with the heat sink 6 and the holder 5, to increase the thermal conductance of the contact.

The procedure of using the test apparatus for the thermal fatigue test of the liquid nitrogen-cooled multilayer film of the present embodiment will be further described below:

(1) before the test is started, the vacuum chamber 1 is at normal temperature, namely 293K, the heat sink 6 is in close contact with the cooling block 7, the liquid nitrogen circulating host 14 is started to enable the circulating cooling system to start to work, the heat conduction process at the time is that the liquid nitrogen circulating host 14, the liquid nitrogen cooling pipe 8, the cooling block 7, the heat sink 6, the heat transfer lead 9, the clamp 5, the electric heating sheet 11 and the multilayer film 12 are used for monitoring the temperature in real time through the temperature sensor 19 on the multilayer film 12 until the temperature value is unchanged and reaches balance, at the time, the temperature of the multilayer film 12 is close to 80K, and in the whole test process, the liquid nitrogen circulating host is always in a running state and does not stop.

(2) When the temperature reaches the equilibrium state for the first time, that is, the temperature approaches to 80K, the electron gun 2 emits an electron beam to strike the multilayer film 12, and at this time, the temperature of the multilayer film 12 is higher than 80K due to the heat load from the electron gun 2, and after a period of time, the temperature value monitored by the temperature sensor 19 is kept unchanged again to reach the second temperature equilibrium.

(3) After the second temperature balance, the PLC controls the electron gun 2 to be closed, and then the driving device 3 drives the precision motion sliding table 4 to drive the heat sink 6 and the holder 5 to move towards the direction far away from the cooling block 7, so that the heat sink 6 is separated from the cooling block 7.

(4) After the heat sink 6 is separated from the cooling block 7, the temperature controller 15 controls the electric heating sheet 11 to be electrified to heat the multilayer film 12 to assist in temperature return, when the temperature value monitored by the temperature sensor 19 reaches 293K, heating is stopped, the strain gauge 20 records the stress strain state of the multilayer film 12 in the whole process (namely the process of temperature from 293K to 80K, electron gun loading, electron gun unloading and temperature to 293K), and the cycle is ended.

(5) Starting the next cycle, the driving device 3 drives the precision motion sliding table 4 to move towards the direction approaching the cooling block 7, so that the heat sink 6 is contacted with the cooling block 7 again, and the processes (1) - (4) are repeated, thereby achieving the process of cyclic loading simulation fatigue.

Wherein, the whole process can be controlled by the PLC 13, thereby realizing the automation of the whole test process.

According to the test device for the thermal fatigue test of the liquid nitrogen cooling multilayer film, provided by the embodiment of the invention, the heat sink 6 and the cooling block 7 are arranged in a detachable contact structure to simulate the thermal load loading process, so that the periodic fatigue process from normal temperature-cooling-loading-unloading-cooling-normal temperature is realized, the working state of the multilayer film 12 of the light source line station is simulated in a real off-line manner, and the reliability of the test result is ensured; by connecting the heat sink 6 and the holder 5 on both sides using a copper braid, the influence on the deformation of the multilayer film can be minimized; the fatigue test process can be effectively accelerated by arranging the electric heating sheet 11 to assist in temperature return; the PLC automatic control can reduce the influence of human factors on the test. The test device for the thermal fatigue test of the liquid nitrogen cooling multilayer film simulates the low-cycle fatigue process of the multilayer film under thermal deformation through a cycle test, provides test verification conditions for finite element analysis results, has significance for liquid nitrogen cooling thermal fatigue research of the multilayer film optical element under a high-power-density light beam, can be used for predicting the fatigue life of the multilayer film, and can be used for researching the thermal fatigue analysis of other liquid nitrogen cooling optical elements after being irradiated by X rays.

The above embodiments are merely preferred embodiments of the present invention, which are not intended to limit the scope of the present invention, and various changes may be made in the above embodiments of the present invention. All simple and equivalent changes and modifications made according to the claims and the content of the specification of the present application fall within the scope of the claims of the present patent application. The invention has not been described in detail in order to avoid obscuring the invention.