阅读说明：本技术 一种低温辐射计吸收腔 (Low-temperature radiometer absorption cavity ) 是由 袁林光 秦艳 董再天 俞兵 范纪红 李燕 吴李鹏 卢飞 于 2021-08-27 设计创作，主要内容包括：本发明属于光学计量技术领域,公开了一种低温辐射计吸收腔,包括：离轴椭球面光阑、斜口-斜底圆柱腔、斜底面；离轴椭球面光阑采用在离轴椭球面开圆孔制作；斜口-斜底圆柱腔采用圆柱腔线切割制作,斜口-斜底圆柱腔一端为斜口,另一端为斜底；斜底面为椭圆形；离轴椭球面光阑的切面与斜口-斜底圆柱腔的斜口端面重合并连接,斜底面与斜口-斜底圆柱腔的斜底端面重合并连接。本发明采用离轴球面光阑,光阑与腔体的连接面与圆柱的轴线之间夹角和吸收腔斜底所在平面与圆柱的轴线之间夹角互余,形成多次反射结构,减少入射到腔中的辐射通过镜面反射和漫反射溢出腔外,从而有效形成光陷阱,使入射到腔中的辐射经过多次反射后被近似完全吸收。(The invention belongs to the technical field of optical measurement, and discloses a low-temperature radiometer absorption cavity, which comprises: an off-axis ellipsoidal diaphragm, an oblique opening-oblique bottom cylindrical cavity and an oblique bottom surface; the off-axis ellipsoidal diaphragm is manufactured by forming a round hole on an off-axis ellipsoidal surface; the bevel-bevel bottom cylindrical cavity is manufactured by linear cutting of a cylindrical cavity, one end of the bevel-bevel bottom cylindrical cavity is a bevel, and the other end of the bevel-bevel bottom cylindrical cavity is a bevel; the inclined bottom surface is elliptical; the section of the off-axis ellipsoidal diaphragm is superposed and connected with the bevel end surface of the bevel-bottom cylindrical cavity, and the bevel bottom surface is superposed and connected with the bevel bottom end surface of the bevel-bottom cylindrical cavity. The invention adopts the off-axis spherical diaphragm, and the included angle between the connecting surface of the diaphragm and the cavity and the axis of the cylinder and the included angle between the plane of the inclined bottom of the absorption cavity and the axis of the cylinder are complementary to form a multi-reflection structure, so that the radiation incident into the cavity is reduced to overflow out of the cavity through mirror reflection and diffuse reflection, and an optical trap is effectively formed, and the radiation incident into the cavity is approximately and completely absorbed after being reflected for multiple times.)

1. A cryogenic radiometer absorption chamber, comprising: an off-axis ellipsoidal diaphragm 1, an oblique opening-oblique bottom cylindrical cavity 2 and an oblique bottom surface 3; the off-axis ellipsoidal diaphragm 1 is formed by making a round hole on an off-axis ellipsoidal surface; the bevel-bottom cylindrical cavity 2 is formed by linear cutting of cylindrical cavities, one end of the bevel-bottom cylindrical cavity 2 is a bevel, and the other end of the bevel-bottom cylindrical cavity is a bevel; the inclined bottom surface 3 is oval; the section of the off-axis ellipsoidal diaphragm 1 is overlapped and connected with the bevel end face of the bevel-bottom cylindrical cavity 2, and the bevel bottom face 3 is overlapped and connected with the bevel end face of the bevel-bottom cylindrical cavity 2.

2. The cryoradiometer absorption cavity of claim 1 wherein the off-axis ellipsoidal diaphragm 1 has a long sectional axis length/₁Is the minor axis length l₂The central axis of the aperture of the round hole is superposed with the axis of the cylinder, and the diameter length d of the round hole is the length l of the minor axis of the tangent plane₂Half of that.

3. The cryoradiometer absorption chamber of claim 2, wherein the cylinder bore length l of the bezel-bezel cylinder 2₃Equal to the minor axis length l of the tangent plane of the off-axis ellipsoidal diaphragm 1₂。

4. The absorption cavity of claim 3, wherein the off-axis ellipsoid amount is α, the included angle between the plane of the oblique opening and the axis of the cylindrical cavity is α, the included angle between the plane of the oblique bottom and the axis of the cylindrical cavity is β, the oblique bottom surface 3 is the included angle between the ellipsoid and the axis of the cylindrical cavity is β, and α + β is 90 °.

5. The cryoradiometer absorption chamber of claim 4, wherein the minor axis length/, of the sloped floor 3₄Equal to the length l of the inner diameter of the cylindrical cavity₃Long axis length of l₅Satisfy l₅＝l₄/sinβ。

6. The cryoradiometer absorption cavity of claim 5, wherein the off-axis ellipsoidal diaphragm 1, the bezel-bezel cylindrical cavity 2, and the bezel 3 are fabricated from electrolytic copper.

7. The absorption chamber of claim 5, wherein the inner surfaces of the off-axis ellipsoidal diaphragm 1, the beveled-bottom cylindrical chamber 2, and the beveled bottom surface 3 are coated with a carbon nanotube array coating.

8. The absorption cavity of the low-temperature radiometer according to claim 5, wherein elliptical ring-shaped flanges are designed and processed on the outer rings of the off-axis ellipsoidal diaphragm 1, the cylindrical cavity oblique opening, the cylindrical cavity oblique bottom and the oblique bottom surface 3, the width of each ring-shaped flange is h, and the off-axis ellipsoidal diaphragm and the cylindrical cavity oblique opening, and the cylindrical cavity oblique bottom and the oblique bottom surface are respectively connected by adopting a diffusion welding mode.

9. The low temperature radiometer absorption chamber of claim 5, wherein α is 30 °, β is 60 °, l₁Is 20mm, l₂Is 10mm, l₃Is 10mm, l₄Is 10mm, l₅Is 14.14 mm.

10. Use of a cryogenic radiometer absorption chamber according to any of claims 1-9 in the field of optical metrology.

Technical Field

The invention belongs to the technical field of optical measurement, relates to a low-temperature radiometer absorption cavity, and particularly relates to a low-temperature radiometer absorption cavity for optical radiation reference.

Background

Cryoradiometers are widely used in the fields of radiometry, photoradiometry, spectroscopy, and astrophysics. Especially in the field of optical radiation measurement, a low-temperature radiometer has become a reference for tracing the source of a radiation source and a radiation detector together, and an important unit of optical radiation measurement can be connected with the low-temperature radiometer, so that the measurement accuracy of corresponding quantity is improved. The low-temperature radiometer is a high-precision sharp light power measuring instrument integrating light collection, mechanical measurement, electrical measurement and calculation, the working principle of the low-temperature radiometer is the same as that of an absolute radiometer, the low-temperature radiometer works at the temperature of liquid helium, so that the limit of environment and materials is broken through, and the uncertainty is reduced by about one order of magnitude compared with that of a normal-temperature absolute radiometer.

The primary purpose of an absorption cavity as a light radiation receiving device for a cryoradiometer is to form a light trap so that radiation incident on the cavity is nearly completely absorbed after multiple reflections. The absorption cavity of the existing low-temperature radiometer mainly comprises a conical cavity with an inclined bottom surface and a cylindrical cavity with an inclined bottom surface, under the condition of the same cavity length and opening area, the absorption rate of the conical cavity with the inclined bottom surface is higher than that of the cylindrical cavity with the inclined bottom surface, but the existing spraying process is difficult to meet the requirement of the conical cavity on high absorption rate blackening. For the cylindrical cavity, when the inclined bottom surface inclination angle and the inner wall blacking are determined, the ratio of the inner surface area of the absorption cavity to the opening area is increased along with the increase of the length of the absorption cavity, and the absorption rate is monotonously increased. And meanwhile, the absorption rate of the cavity can be further improved by using the absorption cavity diaphragm.

Chinese patent publication No. CN 106768372B discloses a black body cavity of a low-temperature radiometer, which comprises a cavity body formed by connecting a right circular cone side surface, a cylindrical side surface and an inclined bottom surface, wherein the right circular cone side surface is used as a diaphragm of an incident aperture of the black body cavity.

Disclosure of Invention

Objects of the invention

The purpose of the invention is: aiming at the requirement of high-precision optical power measurement, a low-temperature radiometer absorption cavity is provided.

(II) technical scheme

In order to solve the technical problem, the invention provides a low-temperature radiometer absorption cavity which comprises an off-axis ellipsoidal diaphragm 1, an oblique opening-oblique bottom cylindrical cavity 2 and an oblique bottom surface 3.

The off-axis ellipsoidal diaphragm 1 is formed by making a round hole on an off-axis ellipsoidal surface, the off-axis amount of the off-axis ellipsoidal surface is alpha, and the length l of a long axis of a tangent plane₁Is the minor axis length l₂The off-axis ellipsoid tangent plane coincides with the bevel opening plane of the bevel opening-bevel bottom cylindrical cavity 2, the central axis of the aperture of the round hole coincides with the axis of the cylinder, and the diameter length d of the round hole is the minor axis length l of the tangent plane₂Half of (1);

the bevel opening-bevel bottom cylindrical cavity 2 is formed by linear cutting of the cylindrical cavity, and the length l of the inner diameter of the cylindrical cavity₃Equal to the minor axis length l of the tangent plane of the off-axis ellipsoidal diaphragm 1₂An included angle between the plane where the oblique opening is located and the axis of the cylindrical cavity is alpha, an included angle between the plane where the oblique bottom is located and the axis of the cylindrical cavity is beta, and the included angle is 90 degrees;

the inclined bottom surface 3 is elliptical, the included angle between the elliptical surface and the axis of the cylindrical cavity is beta, and the length l of the short axis₄Equal to the length l of the inner diameter of the cylindrical cavity₃Long axis length of l₅And satisfy l₅＝l₄/sinβ。

The off-axis ellipsoidal diaphragm 1, the oblique opening-oblique bottom cylindrical cavity 2 and the oblique bottom surface 3 are all made of electrolytic copper.

The inner surfaces of the off-axis ellipsoidal diaphragm 1, the oblique opening-oblique bottom cylindrical cavity 2 and the oblique bottom surface 3 are coated with carbon nano tube array coatings.

The off-axis ellipsoidal diaphragm 1, the cylindrical cavity bevel connection and the 3 outer rings of the bevel bottom surface are all designed and processed with elliptical ring-shaped flanges, the width of each ring-shaped flange is h, and the diffusion welding mode is adopted to realize the connection between the off-axis ellipsoidal diaphragm and the cylindrical cavity bevel connection and the connection between the cylindrical cavity bevel connection and the bevel bottom surface.

(III) advantageous effects

The low-temperature radiometer absorption cavity provided by the technical scheme has the following beneficial effects:

(1) the off-axis spherical diaphragm is adopted, an included angle between the connecting surface of the diaphragm and the cavity and the axis of the cylinder and an included angle between the plane where the inclined bottom of the absorption cavity is located and the axis of the cylinder are complementary to form a multi-reflection structure, so that radiation incident into the cavity is reduced to overflow out of the cavity through mirror reflection and diffuse reflection, an optical trap is effectively formed, and the radiation incident into the cavity is approximately and completely absorbed after being reflected for multiple times.

(2) Oval annular flanges are designed and processed on the outer rings of the off-axis ellipsoidal diaphragm, the inclined opening of the cylindrical cavity, the inclined bottom of the cylindrical cavity and the inclined bottom surface, and are connected in a diffusion welding mode to form a low-temperature radiometer absorption cavity, so that the coating can be prevented from being damaged while the integrity and the tightness of the absorption cavity are ensured.

Drawings

FIG. 1 is a schematic diagram of the composition of an absorption chamber of a cryoradiometer of the present invention.

FIG. 2 is a block diagram of a low temperature radiometer absorption chamber of the present invention.

FIG. 3 is a diagram of an off-axis spherical aperture of the present invention.

FIG. 4 is a schematic view of the oblique mouth-oblique bottom cylindrical cavity of the present invention.

FIG. 5 is a schematic diagram of a bevel-bottom cylindrical cavity according to the present invention.

FIG. 6 is a view showing the structure of the inclined bottom surface of the present invention.

Detailed Description

In order to make the objects, contents and advantages of the present invention clearer, the following detailed description of the embodiments of the present invention will be made in conjunction with the accompanying drawings and examples.

As shown in fig. 1 and u2, the embodiment of the invention is composed of an off-axis ellipsoidal diaphragm 1, a beveled-beveled bottom cylindrical cavity 2 and a beveled bottom surface 3.

As shown in fig. 3, the off-axis ellipsoidal diaphragm 1 is made of 0.1mm thick electrolytic copper material and is formed by forming a circular hole on the off-axis ellipsoidal surface, an elliptical ring-shaped flange is designed and processed on the outer ring, the width of the ring-shaped flange is 1mm, the inner wall is coated with a carbon nanotube array coating, the off-axis amount of the off-axis ellipsoidal surface is 30 °, the long axis of the tangent plane is 20mm, and the short axis is 10 mm. As shown in figures 1 and 2, the section of the off-axis ellipsoid coincides with the bevel face of the bevel-bottom cylindrical cavity 2, the central axis of the aperture of the circular hole coincides with the axis of the cylindrical cavity, and the diameter of the circular hole is 5 mm.

As shown in fig. 4 and 5, the bevel-bottom cylindrical cavity 2 is made of 0.1mm thick electrolytic copper material by linear cutting of the cylindrical cavity, the inner wall of the bevel-bottom cylindrical cavity is coated with a carbon nanotube array coating, elliptical annular flanges are designed and processed on the outer rings of the bevel and the bevel, the width of the annular flange is 1mm, the length of the cylindrical cavity is 40mm, the diameter of the inner cavity is 10mm, the included angle between the plane of the bevel and the axis of the cylinder is 30 degrees, and the included angle between the plane of the bevel and the axis of the cylinder is 60 degrees;

as shown in fig. 6, the inclined bottom surface is made of 0.1mm thick electrolytic copper material, the inner wall is coated with a carbon nanotube array coating and is elliptical, the major axis is 14.14mm, the minor axis is 10mm, the outer ring is designed and processed with an elliptical ring-shaped flange, the width of the ring-shaped flange is 1mm, as shown in fig. 1 and 2, the included angle between the inclined bottom and the axis of the cylinder is 60 degrees, and the inclined bottom surface is superposed with the inclined bottom of the inclined opening-inclined bottom cylindrical cavity;

and connecting an annular flange of the off-axis ellipsoidal diaphragm 1 with an inclined opening-inclined bottom cylindrical cavity 2 inclined opening annular flange by adopting a diffusion welding mode, and connecting the inclined opening-inclined bottom cylindrical cavity 2 inclined bottom annular flange with an inclined bottom surface flange, as shown in figure 2, so as to form a low-temperature radiometer absorption cavity.

The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.