Light limiting valve for Einstein probe satellite FXT load

Abstract

The utility model provides a light limiting valve for an Einstein probe satellite FXT load, which is nested in a groove of an upper cover of a shielding box, and the nearest distance between the light limiting valve and the upper surface of a focal plane detector is 1mm; the light limiting valve is of an inverted-cone-shaped structure and is composed of a light limiting valve support cover, a beryllium shield, an aluminum shield, a magnet, a light limiting valve support and a light limiting valve bottom support. The internal shielding material of the light limiting valve is beryllium of 1 mm, aluminum of 1 mm and a magnet of 1 mm. The three layers of shields are placed layer by layer along the light limiting valve bracket, and the exteriors of four legs at the bottom of the light limiting valve bracket cover tightly press the three layers of shields to limit the transverse displacement of the three layers of shields; the plane flange of the light limiting valve bracket cover simultaneously presses each layer of shielding, so that axial displacement is prevented; a plurality of grooves are formed in the side face of the light limiting valve support, and the light limiting valve bottom supports are inserted into the grooves in the side face of the light limiting valve support. The light limiting valve support cover, the light limiting valve bottom support and the light limiting valve support are fixed through screws. On the premise that the thermal expansion relation is not restrained, the mechanical property of the thermal expansion joint is guaranteed.

Description

Technical Field

[0001] The utility model belongs to the technical field of space astronomical observation, and particularly relates to a light-limiting valve for the FXT payload of the Einstein Probe satellite. Background Art

[0002] The payload of the Einstein Probe satellite (EP) includes a soft X-ray (0.5 - 4 keV) monitor (WXT) with a large field of view (3600 square degrees) and a deep follow-up X-ray telescope (FXT) with a field of view of about 38 arcminutes.

[0003] The FXT telescope includes an upper end assembly and a lower end assembly. The lower end assembly includes a detector chassis, a cryocooler, a heat pipe, a radiation plate and other components of a heat dissipation system. The detector chassis includes a shielding box and a focal plane detector box. The detector chassis includes a shielding box, a focal plane detector box, a light-limiting valve, etc. Its main function is to provide a good spatial force, thermal and physical installation environment for the pn-CCD. A light-limiting valve is designed directly above the focal plane detector. The light-limiting valve is composed of a bracket, a beryllium shield, an aluminum shield, etc.

[0004] The current light-limiting valve usually has a single-bracket structure and only has the function of limiting light. The structural design for shielding space low-energy electrons is not considered. Such a light-limiting valve is not suitable for the field of space astronomical detection, and space low-energy electrons will cause a significant increase in the background noise of the focal plane detector. Content of the Utility Model

[0005] To solve the above technical problems, the utility model provides a light-limiting valve that ensures its mechanical properties without restricting its thermal expansion relationship.

[0006] To achieve the above object, the utility model adopts the following technical solutions:

[0007] The light-limiting valve for the FXT payload of the Einstein Probe satellite is composed of a light-limiting valve bracket cover, a beryllium shield, an aluminum shield, a magnet, a light-limiting valve bracket and a light-limiting valve bottom support. The light-limiting valve includes three layers of shielding, and the shielding materials are 1 mm beryllium, 1 mm aluminum, and 1 mm magnet, that is, from the inside to the outside are the beryllium shield, the aluminum shield, and the magnet in sequence. The three layers of shielding are placed layer by layer along the light-limiting valve bracket. The outer sides of the four legs at the bottom of the light-limiting valve bracket cover press against the three layers of shielding to limit their lateral displacement. The flat flange of the light-limiting valve bracket cover also presses against the three layers of shielding to prevent axial displacement. A plurality of grooves are provided on the side of the light-limiting valve bracket, and the light-limiting valve bottom support is inserted from the grooves on the side of the light-limiting valve bracket. The light-limiting valve bracket cover, the light-limiting valve bottom support and the light-limiting valve bracket are fixed.

[0008] Further, the light-limiting valve is nested in the groove of the upper cover of the shielding box, and the closest distance to the upper surface of the focal plane detector is 1 mm.

[0009] Furthermore, the light-limiting valve is of an inverted conical structure.

[0010] Furthermore, the light-limiting valve bracket is made of oxygen-free copper.

[0011] Furthermore, the outer wall of the light-limiting valve bracket is designed with an inclination angle to facilitate the placement of beryllium shielding, aluminum shielding, and magnets.

[0012] Beneficial effects:

[0013] The present utility model designs a light-limiting valve composed of components such as a light-limiting valve bracket, aluminum shielding, beryllium shielding, and magnets. It can not only play the role of limiting the light path. At the same time, the magnetic field of the magnets polarizes low-energy electrons in space, making them unable to reach the focal plane detector, thereby reducing the background noise introduced by it and shielding the low-energy electrons in space that affect the noise of the detector, playing the role of improving the signal-to-noise ratio of the focal plane detector. Description of the drawings

[0014] Figure 1 is an exploded view of the light-limiting valve of the present utility model;

[0015] Figure 2 is a sectional view of the light-limiting valve of the present utility model.

[0016] Among them, the reference numerals are: light-limiting valve bracket cover 1, beryllium shielding 2, aluminum shielding 3, magnet 4, light-limiting valve bracket 5, light-limiting valve bottom support 6. Specific embodiments

[0017] In order to make the purpose, technical solutions, and advantages of the present utility model clearer, the following further details the present utility model in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present utility model and are not used to limit the present utility model. In addition, the technical features involved in the various embodiments of the present utility model described below can be combined with each other as long as they do not conflict with each other.

[0018] As Figure 1 , Figure 2As shown, the light-limiting valve of the present utility model is nested in the groove of the upper cover of the shielding box, and the closest distance to the upper surface of the pn-CCD is 1 mm. The light-limiting valve is of an inverted conical structure and is composed of a light-limiting valve support cover 1, a beryllium shield 2, an aluminum shield 3, a magnet 4, a light-limiting valve support 5, and a light-limiting valve bottom support 6. Three layers of shielding are arranged inside the light-limiting valve, and the materials are 1-mm beryllium, 1-mm aluminum, and 1-mm magnet respectively to reduce the background caused by low-energy electrons, that is, the beryllium shield 2, the aluminum shield 3, and the magnet 4 from the inside to the outside in sequence; the three layers of shielding are placed layer by layer along the light-limiting valve support 5, and then the outside of the four legs at the bottom of the light-limiting valve support cover 1 presses the three layers of shielding to restrict their lateral displacement; the planar flange of the light-limiting valve support cover 1 presses each layer of shielding at the same time to prevent axial displacement; a plurality of grooves are arranged on the side surface of the light-limiting valve support 5, and the light-limiting valve bottom support 6 is inserted into the grooves on the side surface of the light-limiting valve support 5; the light-limiting valve support cover 1, the light-limiting valve bottom support 6 and the light-limiting valve support 5 are fixed by screws.

[0019] To ensure the physical properties and match the force and heat properties at the same time, the material of the light-limiting valve support 5 is the same as that of the shielding box, both being oxygen-free copper. The light-limiting valve support 5 also has installation interfaces with the shielding box, the light-limiting valve support cover 1, and the light-limiting valve bottom support 6. The outer wall of the light-limiting valve support 5 is designed with an 86° inclination angle to facilitate the placement of the shielding layer.

[0020] Although the three layers of shielding do not have installation interfaces, since both the lateral and longitudinal displacements are restricted, without restricting their thermal expansion relationship, their mechanical properties can still be ensured.

Claims

1. A light-limiting valve for the FXT payload of the Einstein Probe satellite, characterized in that, It is composed of a collimator bracket cover, beryllium shield, aluminum shield, magnet, collimator bracket, and collimator bottom support; the collimator includes 3 layers of shields, and the shielding materials are 1 mm beryllium, 1 mm aluminum, and 1 mm magnet respectively, that is, the beryllium shield, aluminum shield, and magnet are arranged from the inside to the outside in sequence; the 3 layers of shields are placed layer by layer along the collimator bracket, and the outside of the four legs at the bottom of the collimator bracket cover presses tightly on the 3 layers of shields to limit their lateral displacement; the flat flange of the collimator bracket cover also presses tightly on the 3 layers of shields to prevent axial displacement; multiple grooves are provided on the side of the collimator bracket, and the collimator bottom support is inserted from the grooves on the side of the collimator bracket; the collimator bracket cover, collimator bottom support are fixed to the collimator bracket.

2. The light-limiting valve for the FXT payload of the Einstein Probe satellite according to claim 1, characterized in that, The collimator is nested in the groove of the upper cover of the shielding box, and the closest distance to the upper surface of the focal plane detector is 1 mm.

3. The light-limiting valve for the FXT payload of the Einstein Probe satellite according to claim 1, wherein, The collimator is of an inverted conical structure.

4. The light-limiting valve for the FXT payload of the Einstein Probe satellite according to claim 1, wherein, The collimator bracket is made of oxygen-free copper.

5. The light-limiting valve for the FXT payload of the Einstein Probe satellite according to claim 1, characterized in that, The outer wall of the collimator bracket is designed with an inclination angle to facilitate the placement of the beryllium shield, aluminum shield, and magnet.

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