CN113936840B - A temperature-controlled X-ray deformable mirror - Google Patents

Abstract

The invention provides a temperature-controlled X-ray deformable mirror, which includes a substrate and an optical reflection film arranged on the upper surface of the substrate, the optical reflection film is coated on the upper surface of the substrate at the position of the center line, and several heat-conducting contacts Points are arranged on the substrate outside the optical reflective film, and each thermal contact is set to produce local thermal expansion and contraction under the action of high temperature or low temperature, so that the temperature-controlled X-ray deformable mirror can produce the required Surface shape; the upper surface of the base is provided with slide rails, and the heat-conducting contacts can move freely along the extending direction of the slide rails. The temperature-controlled X-ray deformable mirror of the present invention is provided with a movable heat-conducting contact, and the heat-conducting contact produces local thermal expansion and contraction under the action of high temperature or low temperature, so that according to the distribution of the actual surface shape error, it can be adjusted by moving the contact Points are used to compensate the convex or concave shape at different positions to achieve the target surface shape characteristics.

Description

A temperature-controlled X-ray deformable mirror

technical field

The invention belongs to the field of active X-ray optical wavefront correction, and in particular relates to a temperature-controlled deformable mirror, which is used for focusing and wavefront adjustment of grazing incident X-rays.

Background technique

In the hard X-ray band, the refractive index of any material is close to 1. Therefore, high reflectivity can only be obtained at small grazing incidence angles. Therefore, the reflective element with grazing incidence is the main form to realize functions such as hard X-ray imaging and focusing. After X-rays are collimated, deflected and focused by components, the wavefront characteristics and coherence of the beam will be significantly destroyed. For optical components, especially reflective components, the deviation between the surface shape produced by polishing and coating and the ideal surface shape will affect the wavefront of the beam. At present, the best direct surface polishing technology in the world cannot fully satisfy the limit focus or the maintenance of coherence. However, the traditional mechanical bending has less adjustment dimensions and cannot form a perfect surface shape.

The active surface shape correction technology represented by piezoelectric deformation has been paid attention to in recent years, which can produce a large amount of deformation, and can accurately compensate the surface shape error online and in real time. However, the actuators of piezoelectric deformable mirrors are deposited or pasted on piezoelectric ceramics, and have a fixed arrangement, which limits the compensation of piezoelectric deformable mirrors for surface shape. At present, other compensation technologies such as temperature control and magnetic control are rarely used in the world, and they are all fixed arrangement designs similar to piezoelectric deformable mirrors.

Contents of the invention

The object of the present invention is to provide a temperature-controlled X-ray deformable mirror for targeted compensation of surface shape errors at different positions of the mirror surface.

In order to achieve the above object, the present invention provides a temperature-controlled X-ray deformable mirror, comprising a substrate and an optical reflection film arranged on the upper surface of the substrate, the optical reflection film is coated on the upper surface of the substrate at the position of the centerline , and a number of heat-conducting contacts are arranged on the substrate outside the optical reflection film, and each heat-conducting contact is set to produce local thermal expansion and contraction under the action of high temperature or low temperature, thereby causing the temperature-controlled X-ray to deform The mirror produces the required surface shape; the upper surface of the base is provided with a slide rail, and the heat-conducting contacts can move freely along the extending direction of the slide rail.

Each thermal contact includes a vertical contact rod and a joint located at the top of the contact rod, through which the contact rod fully contacts the base.

The base is provided with a groove structure at the lower part of the slide rail, and the opening of the groove structure is aligned with the slide rail; the contact bar of the heat-conducting contact is accommodated in the groove structure and the joint is clamped on the slide rail.

The extending direction of the sliding rail is parallel to the central line, and a part of the sliding rail extends to the area outside the base.

The heat conduction contacts are arranged in double rows, and several pairs of heat conduction contacts are symmetrically arranged on both sides of the optical reflection film, so that the temperature acts on the area of the optical reflection film uniformly and symmetrically.

Each pair of heat-conducting contacts arranged symmetrically on both sides of the optical reflection film is respectively connected to a heat source and/or a cold source.

Each thermally conductive contact is connected to a heat source and/or a cool source respectively.

The changeover switch is connected with the heat-conducting contact, the heat source and/or the cold source through a heat-conducting wire, and the heat-conducting wire is wrapped with a heat-insulating material.

The temperature-controlled X-ray deformable mirror also includes a heat-insulating cavity, which is a cavity placed in a low-vacuum environment or a closed cavity isolated from the environment, and the temperature-controlled X-ray deformable mirror is in addition to The parts other than the optical reflective film are placed in the heat-insulating cavity.

The substrate is connected to a thermistor at different positions and each thermal contact, and the temperature is measured through the thermistor and the resistance measuring device, so as to feed back the resistance reading of the thermistor to a control output in real time system, the temperature control accuracy of the control output system is at most 0.1 degrees centigrade error.

The temperature-controlled X-ray deformable mirror of the present invention is provided with a movable heat-conducting contact, and the heat-conducting contact produces local thermal expansion and contraction under the action of high temperature or low temperature, so that according to the distribution of the actual surface shape error, the contact can be moved by moving the contact Points are used to compensate the convex or concave shape at different positions to achieve the target surface shape characteristics. That is to say, the present invention overcomes the shortcomings of traditional piezoelectric, temperature-controlled or magnetic-controlled active deformable mirror actuators that are arranged and fixed, and there are limitations on the correction of the surface shape. The swelling or contraction of the mirror surface is locally formed by thermal expansion and contraction caused by high temperature or low temperature, so as to compensate for the surface shape error at the corresponding position.

Description of drawings

Fig. 1 is a schematic structural diagram of a temperature-controlled X-ray deformable mirror according to an embodiment of the present invention.

Figure 2 is a schematic diagram of the surface curvature control of the thermal contact under the action of high temperature and low temperature. Under the action of high temperature or low temperature, the thermal contact makes the surface of the mirror body undergo local thermal expansion and contraction, thereby producing the required bulge or depression .

Fig. 3 is a schematic diagram showing the variation of surface shape height with mirror length produced by thermally conductive contacts of copper materials at different temperatures on the mirror surface of silicon material.

Detailed ways

The present invention will be further described below in conjunction with specific embodiments. It should be understood that the following examples are only used to illustrate the present invention but not to limit the scope of the present invention.

As shown in FIGS. 1-2 , a temperature-controlled X-ray deformable mirror according to an embodiment of the present invention includes a substrate 11 (ie, a mirror body substrate) and an optical reflection film 12 disposed on the upper surface of the substrate 11 . The upper surface of the optical reflection film 12 constitutes a mirror surface.

Wherein, the base 11 (that is, the base of the mirror body) is rectangular, or other common shapes such as trapezoid, spinning cone, and circle. The material of the substrate 11 of the temperature-controlled X-ray deformable mirror is a material with a thermal conductivity greater than 100W/m·K, such as a single crystal silicon or silicon carbide substrate, so that the mirror surface can undergo rapid thermal response under temperature changes.

The temperature-controlled X-ray deformable mirror has a centerline extending along the meridional direction of the mirror length on the upper surface of the base 11 . In this embodiment, the optical reflective film 12 is coated on the upper surface of the base 11 at the position of the center line, and several pairs of heat-conducting contacts 2 are symmetrically arranged on both sides of the optical reflective film 12, so as to The temperature acts on the area of the optical reflection film 12 uniformly and symmetrically, so that the temperature-controlled X-ray deformable mirror produces controllable surface fluctuations. The heat-conducting contacts 2 are arranged in two rows, but in other embodiments, the arrangement of the temperature control contacts is not limited to the described double-row array, and may also be a multi-row array or multi-row multi-column Correspondingly, the heat-conducting contacts 2 can also be arranged at any position on the substrate 11 other than the optical reflection film 12 .

As shown in Figure 2, due to thermal expansion and contraction, each heat conduction contact 2 is set so that under the effect of high temperature or low temperature, the surface of the substrate 11 within a certain radius with each heat conduction contact 2 as the center produces a local Thermal expansion and contraction, thereby producing the required bulge or depression (usually, high temperature causes bulge, low temperature causes depression), and then makes the temperature-controlled X-ray deformable mirror produce the required surface shape to correct the beam wavefront and produce the required Diffusion or focus effect. Each pair of thermally conductive contacts that are symmetrical along the center line work together to change the surface shape of the middle region of the optical reflection film 12 to obtain an ideal wavefront.

Referring to FIG. 1 again, a slide rail 13 is provided on the upper surface of the base 11 , and the heat-conducting contacts 2 can move freely along the extending direction of the slide rail 13 . Under X-ray grazing incidence conditions, the wavefront error and surface shape height error Δd satisfy the following relationship: /> where K is the wave vector. Therefore, by adjusting the surface shape and reducing the surface shape height error Δd in each region, an ideal and perfect wavefront can be obtained. The wavefront error of an optical path comes from the surface error of the light source and all optical components, but an active compensation mirror can realize effective correction of the wavefront error in its meridional dimension. Thus, the present invention realizes the active control of the surface shape of the grazing incidence mirror. Since the temperature contact in the design can be moved, the same mirror system can be used in a complex beam wavefront environment or under different beams to correct The surface error of the mirror itself and the wavefront error caused by other components in the front optical path. It can also be used in combination with other mechanical and adaptive deformable mirror systems to form complementary surface shape corrections using temperature control and spatial frequency differences of mechanical and piezoelectric excitations. For monochromators or mirrors with high thermal loads in front of synchrotron radiation and free electron lasers, which use thermal deformation to compensate for surface shape errors under thermal loads, it will be more ideal from the perspective of spatial frequency.

Specifically, each thermal contact 2 includes a vertical contact rod 21 and a joint 22 located at the top of the contact rod, through which the contact rod 21 is fully in contact with the base 11 to conduct heat when there is a temperature difference. Transfer is heat conduction. The base 11 is provided with a groove structure at the lower part of the slide rail 13, and the opening of the groove structure is aligned with the slide rail 13; the contact rod 21 of the thermal contact 2 is accommodated in the groove structure and the joint 22 is clamped on the slide rail 13, so as to achieve the effect that the heat conduction contact 2 is fully in contact with the base 11, and enable the heat conduction contact 2 to move freely along the extending direction of the slide rail 13. The extending direction of the sliding rail 13 is parallel to the central line, and a part of the sliding rail 13 extends to the area outside the base 11 , so as to ensure the running position of the thermal contact 2 on the base 11 . In this embodiment, since several pairs of thermal contacts 2 are symmetrically arranged on both sides of the optical reflection film 12 , there are two slide rails 13 , which are located on both sides of the optical reflection film 12 .

In addition, under the premise of not destroying the optical reflection film 12, the two slide rails 13 are arranged as close to the area of the optical reflection film 12 as possible, such as the shortest distance between the two slide rails 13 and the boundary of the optical reflection film 12 is less than 10 mm, In order to increase the sensitivity of temperature regulation to the surface shape of the mirror surface of the temperature-controlled X-ray deformable mirror.

In this embodiment, each pair of thermal contacts 2 symmetrically arranged on both sides of the optical reflection film 12 is respectively connected to a heat source 4 and a cold source 5 through a switch 3, so as to pass through the switch The switch 3 switches between the heat source 4 and the cold source 5 . Wherein, for each pair of heat conduction contacts 2 , the static contact of the corresponding changeover switch 3 is connected to the heat conduction contacts 2 , and the two movable contacts are respectively connected to the heat source 4 and the cold source 5 . In other embodiments, each pair of heat conduction contacts 2 is not limited to the switch between the described heat source and cold source, it is also possible that each pair of heat conduction contacts 2 is only connected to a heat source 4 or only to a heat sink 5 connection for individual heating or cooling control. Further, in other embodiments, each thermal contact 2 can also be connected to a heat source 4 and a cold source 5 at the same time through a switch 3, or only connected to a heat source 4, or only connected to a cold source 5 .

The logarithm of the heat conduction contacts 2 (that is, the number of heat sources 4 and cold sources 5) can be one to dozens according to the length of the temperature-controlled X-ray deformable mirror and the actual application, so that each pair of heat conduction contacts 2 can compensate for temperature control The local surface defect of the X-ray deformable mirror or the surface error of the low-frequency modulation. Specifically, when the error distribution of the mirror surface shape is obtained from the measurement, a certain number of thermal contacts 2 are set to manually or electrically slide to the position of the surface shape to be corrected, so as to compensate the local surface shape at this position, instead of The required contacts then remain in the slide rail 3 which extends to an area outside the base 11 .

The changeover switch 3 is connected with the heat conduction contact 2 , the heat source 4 and/or the cold source 5 through heat conduction wires. The material of heat conduction contact 2 and heat conduction line must keep good thermal conductivity (for example, material can be copper, and its thermal conductivity is about 398W/m K; Aluminum, its thermal conductivity is 237W/m K; Silver , whose thermal conductivity is 411W/m·K; gold, whose thermal conductivity is 315W/m·K, etc.), and reduce the distance from the heat source and cold source to the contact so that the heat source and cold source to the contact The distance is at least 10 cm, and the heat conduction wire is wrapped with special heat insulation material (especially for the cold source) to ensure that the contact is close to the set temperature of the heat source or cold source. The slide rail 13 of the mirror body is made of a material with poor thermal conductivity (that is, the thermal conductivity of the material of the slide rail 13 is lower than 10W/m·K), so as to prevent direct heat conduction between the contacts, thereby affecting each other.

The parts of the temperature-controlled X-ray deformable mirror of the present invention except the optical reflective film 12 (that is, the base 11, the slide rail 13, the thermal contact 2, the switch 3, the thermal conductive wire, the heat source 4 and the cold source 5), especially It is the part of the heat conduction line, which can be insulated with heat insulating materials to prevent the rapid heat dissipation of the fast mirror surface, causing the surface temperature to not easily reach a balanced state. Specifically, the temperature-controlled X-ray deformable mirror of the present invention also includes a heat-insulating cavity, and the heat-insulating cavity is a cavity placed in a low-vacuum environment or a closed cavity isolated from the environment, and the temperature-controlled X-ray deformable mirror of the present invention The parts of the X-ray deformable mirror except the optical reflection film 12 (especially the heat conduction line part) are placed in the above-mentioned heat-insulating cavity to reduce the heat exchange with the air and prevent the environment from disturbing the heat conduction, causing the mirror surface to fail to reach quickly. required heat balance.

The substrate 11 is connected to a high-precision thermistor at different positions and each thermal contact 2, and the temperature is measured through the thermistor and the resistance measuring device to feed back the resistance reading of the thermistor to a high value in real time. High-precision control output system, thereby maintaining the precision of temperature control. High-precision control The temperature control accuracy of the output system needs to maintain an accuracy of at most 0.1 degrees Celsius error, so that the surface shape maintains high stability.

The above-mentioned thermal contact 2, heat source 4 and cold source 5 constitute a temperature control surface shape control system, which can act on the mirror body to correct the surface shape alone, or can be combined with other mechanical bending mirrors or piezoelectric The use of adaptive mirrors such as deformable mirrors is mainly based on the characteristics of temperature and other deformations that correspond to different spatial frequencies for correcting surface shape errors, so as to achieve more flexible surface shape correction effects. That is to say, the temperature-controlled X-ray deformable mirror of the present invention can also be provided with a piezoelectric deformation device and/or a mechanical bending device for changing the surface shape of the temperature-controlled X-ray deformable mirror.

The length of the temperature-controlled X-ray deformable mirror (along its mirror long meridian direction) can be a meter-level long mirror, or a centimeter-level small mirror. The surface shape of the mirror surface applicable to the present invention is not limited, and the surface shape of the mirror surface may include a common plane, various types of cylindrical surfaces, toroidal surfaces, various types of spherical surfaces, and the like.

Figure 3 shows a schematic diagram of the surface height of the middle area of the two heat-conducting contacts changing with the length of the mirror after a pair of simple copper heat-conducting contacts heat the mirror surface of silicon material, in which the four lines in the figure respectively represent The cases at 20, 60, 80 and 100°C are shown. Due to the low thermal conductivity of silicon, a temperature change of tens of degrees only causes a change of about 10 degrees in the center of the mirror surface. However, because the temperature is very sensitive to the change of the surface shape, the mirror surface still has a local height change of more than 100 nanometers. For a substrate of a particular size and material, a temperature change can generate a corresponding thermally induced response function. The thermal response function can be measured by a high-precision Fizeau laser interferometer. Using the thermal response function, the relationship between the surface shape change and temperature of the temperature-controlled X-ray deformable mirror can be directly calculated, and then the resistance reading of the thermistor can be determined. .

What is described above is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Various changes can also be made to the above embodiments of the present invention. All simple and equivalent changes and modifications made according to the claims and description of the application for the present invention fall within the protection scope of the claims of the patent of the present invention. What is not described in detail in the present invention is conventional technical content.

Claims (10)

1. A temperature-controlled X-ray deformable mirror, characterized in that, comprises a substrate and an optical reflective film disposed on the upper surface of the substrate, the optical reflective film is coated at the position of the center line on the upper surface of the substrate, and A number of heat-conducting contacts are arranged on the substrate outside the optical reflection film, and each heat-conducting contact is set to produce local thermal expansion and contraction under the action of high temperature or low temperature, thereby causing the temperature-controlled X-ray deformable mirror to generate The required surface shape; the upper surface of the base is provided with slide rails, and the heat-conducting contacts can move freely along the extending direction of the slide rails. 2. The temperature-controlled X-ray deformable mirror according to claim 1, wherein each thermal contact includes a vertical contact rod and a joint positioned at the top of the contact rod, through which the contact rod and the base are fully connected. touch. 3. The temperature-controlled X-ray deformable mirror according to claim 2, wherein the base is provided with a groove structure at the bottom of the slide rail, and the opening of the groove structure is aligned with the slide rail; The contact rod is accommodated in the groove structure and the joint is clamped on the slide rail. 4 . The temperature-controlled X-ray deformable mirror according to claim 3 , wherein the extending direction of the slide rail is parallel to the center line, and a part of the slide rail extends to the area outside the base. 5 . The temperature-controlled X-ray deformable mirror according to claim 1 , wherein the heat-conducting contacts are arranged in a multi-row array. 6. The temperature-controlled X-ray deformable mirror according to claim 5, wherein the heat-conducting contacts are arranged in a double-row array, and several pairs of heat-conducting contacts are symmetrically arranged on both sides of the optical reflection film , so that the temperature acts uniformly and symmetrically on the region of the optical reflective film, and each pair of heat-conducting contacts symmetrically arranged on both sides of the optical reflective film is only connected to the heat source, only to the cold source, Or connect to heat source and cool source at the same time. 7 . The temperature-controlled X-ray deformable mirror according to claim 5 , wherein each thermal contact is connected to only the heat source, only to the cold source, or both to the heat source and the cold source through a switch. 8. The temperature-controlled X-ray deformable mirror according to claim 6 or 7, characterized in that, when the heat-conducting contact is only connected to the heat source through a switch, the switch is connected to the heat-conducting contact and the heat-conducting contact through a heat-conducting wire. The above-mentioned heat source is connected, and the heat-conducting wire is wrapped with heat-insulating material; When the heat conduction contact is only connected to the cold source through the switch, the switch is connected to the heat conduction contact and the cold source through a heat conduction line, and the heat conduction line is wrapped with a heat insulating material; The heat conduction contact is simultaneously connected to the heat source and the cold source through a switch, and the switch is connected to the heat conduction contact, the heat source and the heat sink through a heat conduction line, and the heat conduction line is wrapped with a heat insulating material. 9. The temperature-controlled X-ray deformable mirror according to claim 1, further comprising a heat-insulating cavity, which is a cavity placed in a low-vacuum environment or a closed cavity isolated from the environment body, and the temperature-controlled X-ray deformable mirror is placed in the heat-insulating cavity except for the optical reflection film. 10. The temperature-controlled X-ray deformable mirror according to claim 1, characterized in that, the substrate is connected to a thermistor at different positions and each thermal contact, and is measured by the thermistor and resistance The device is used for temperature measurement to feed back the resistance reading of the thermistor in real time to a control output system with a temperature control accuracy of at most 0.1 degrees Celsius error.