阅读说明：本技术 一种降低银表面高能区二次电子发射系数的方法 (Method for reducing secondary electron emission coefficient of silver surface high-energy area ) 是由 何鋆 王琪 封国宝 杨晶 苗光辉 白春江 崔万照 于 2020-06-03 设计创作，主要内容包括：本发明涉及一种降低银表面高能区二次电子发射系数的方法,属于真空电子学二次电子发射抑制技术领域,尤其涉及一种利用薄膜降低银表面高能区二次电子发射系数的方法,所述的高能区是指入射到银表面电子的能量范围为250-3000ev。采用NPB材料为薄膜材料,有效降低了银表面高能区的二次电子发射系数。可在银表面大面积制备NPB薄膜,降低了薄膜制备成本。本发明提出的方法对银基底没有温度等特殊要求,在抑制二次电子倍增效应领域具有广泛的应用前景。(The invention relates to a method for reducing secondary electron emission coefficient of a silver surface high-energy area, belongs to the technical field of secondary electron emission suppression of vacuum electronics, and particularly relates to a method for reducing the secondary electron emission coefficient of the silver surface high-energy area by using a film, wherein the high-energy area refers to that the energy range of incident electrons on the silver surface is 250-3000 ev. The NPB material is adopted as the film material, so that the secondary electron emission coefficient of the silver surface high-energy area is effectively reduced. The NPB film can be prepared on the silver surface in a large area, and the film preparation cost is reduced. The method provided by the invention has no special requirements on the temperature and the like of the silver substrate, and has wide application prospect in the field of inhibiting the secondary electron multiplication effect.)

1. A method for reducing the secondary electron emission coefficient of a silver surface high-energy area is characterized in that: the method is characterized in that an NPB film with a nanometer-level thickness is prepared on the silver surface of a microwave component through a vacuum evaporation technology, and the secondary electron emission coefficient of the silver surface high-energy area of the microwave component is reduced.

2. The method for reducing the secondary electron emission coefficient of the silver surface high energy region according to claim 1, wherein: the method comprises the following specific steps:

firstly, placing a microwave component with a silver coating on the surface into a vacuum evaporation system, and vacuumizing;

secondly, shielding the silver plating layer of the microwave component by using a baffle, opening the NPB beam source baffle, supplying current to the NPB beam source and heating the NPB beam source;

thirdly, opening a baffle for shielding the silver coating of the microwave component, and evaporating an NPB film on the surface of the silver coating of the microwave component;

and fourthly, after the evaporation is finished, cutting off the current of the NPB beam source, taking out the microwave component after the temperature is reduced to the room temperature, and finishing the NPB evaporation on the surface of the silver coating of the microwave component.

3. The method for reducing the secondary electron emission coefficient of the silver surface high energy region according to claim 2, wherein: in the first step, vacuum is applied to 10^-4Pa。

4. The method for reducing the secondary electron emission coefficient of the silver surface high energy region according to claim 2, wherein: in the second step, the heating temperature of the NPB beam source is 450-500 ℃.

5. The method for reducing the secondary electron emission coefficient of the silver surface high energy region according to claim 4, wherein: the heating temperature of the NPB beam source is 450 ℃.

6. The method for reducing the secondary electron emission coefficient of the silver surface high energy region according to claim 4, wherein: the heating temperature of the NPB beam source is 500 ℃.

7. The method for reducing the secondary electron emission coefficient of the silver surface high energy region according to claim 2, wherein: in the third step, the evaporation time is 4-40 s.

8. The method for reducing the secondary electron emission coefficient of the silver surface high energy region according to claim 2, wherein: in the third step, the thermal evaporation speed of NPB molecules is

9. The method for reducing the secondary electron emission coefficient of the silver surface high energy region according to claim 7, wherein: the high-energy region is the energy range of the electrons incident to the surface of the silver is 250-3000 eV.

10. The method for reducing the secondary electron emission coefficient of the silver surface high energy region according to claim 2, wherein: in the fourth step, the thickness of the NPB coating is 5nm-150 nm.

Technical Field

The invention relates to a method for reducing secondary electron emission coefficient of a silver surface high-energy area, belongs to the technical field of secondary electron emission suppression of vacuum electronics, and particularly relates to a method for reducing the secondary electron emission coefficient of the silver surface high-energy area by using a film, wherein the high-energy area refers to that the energy range of incident electrons on the silver surface is 250-3000 ev.

Background

High power microwave components are an important component of satellite payloads and to reduce rf losses, the component surfaces are typically plated with a thickness of silver material. Because the high-power microwave component works in a special space environment, the silver surface of the high-power microwave component can generate a secondary electron multiplication phenomenon under the bombardment of high-energy electrons in the universe, so that micro-discharge is induced, and the performance of a satellite is seriously influenced. Reducing the secondary electron emission coefficient of the silver surface in the high energy region is one of the effective means for inhibiting the secondary electron multiplication phenomenon and further avoiding micro-discharge. At present, the secondary electron emission coefficient of the surface of a component is reduced internationally mainly by constructing a micro-trap structure on the silver surface and coating a material with a low secondary electron emission coefficient. The size of the micro trap structure is in micron order, and the area is large (more than 10 cm)²) The preparation time is long and the cost is high. The coating of the material with low secondary electron emission coefficient has special requirements on the temperature of the substrate and poor compatibility with the silver plating process of the microwave part, so that the applicable objects are limited.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the method overcomes the defects of poor compatibility and high cost of the manufacturing process of silver-plated microwave components in the prior art, and provides the method for reducing the secondary electron emission coefficient of the silver surface high-energy area with low cost.

The technical scheme of the invention is as follows:

a method for reducing secondary electron emission coefficient of silver surface high energy zone is to prepare NPB film with nanometer thickness on silver surface of microwave component by vacuum evaporation technology to reduce secondary electron emission coefficient of silver surface high energy zone of microwave component, which comprises the following steps:

firstly, placing a microwave component with a silver coating on the surface into a vacuum evaporation system, and vacuumizing to 10 DEG^-4Pa；

Secondly, shielding the silver coating of the microwave component by using a baffle, opening the NPB beam source baffle, electrifying the NPB beam source and heating the NPB beam source to 450-500 ℃;

thirdly, opening a baffle for shielding the silver coating of the microwave component, and evaporating an NPB film on the surface of the silver coating of the microwave component, wherein the evaporation time is 4-40s, and the thermal evaporation speed of NPB molecules is

And fourthly, after the evaporation is finished, cutting off the current of an NPB beam source, taking out the microwave component after the temperature is reduced to the room temperature, and finishing the NPB evaporation on the surface of the silver coating of the microwave component, wherein the NPB coating can reduce the secondary electron emission coefficient of the microwave component with the energy range of the silver surface being more than or equal to 250eV, the NPB coating has good compatibility with the silver coating on the surface of the microwave component, the thickness of the NPB coating is 5nm-150nm, the NPB coating is a thin film, and the NPB is N, N ' -bis- (1-aminophenyl) -1,1 ' -biphenyl-4,4 ' -diamine.

The invention has the beneficial effects that: the NPB material is adopted as the film material, so that the secondary electron emission coefficient of the silver surface high-energy area is effectively reduced. The NPB film can be prepared on the silver surface in a large area, and the film preparation cost is reduced. The method provided by the invention has no special requirements on the temperature and the like of the silver substrate, and has wide application prospect in the field of inhibiting the secondary electron multiplication effect.

Drawings

FIG. 1 shows the results of secondary electron emission coefficient measurements of NPB thin-film silver coupons prepared with different thicknesses.

Detailed Description

The present invention will be described in detail with reference to specific examples.

The method for reducing the secondary electron emission coefficient of the silver surface high energy area by utilizing the NPB film, which is provided by the invention, is adopted to prepare the NPB film on the surface of a silver sample wafer with the size of 10mm multiplied by 0.3mm by using a vacuum evaporation technology, so that the secondary electron emission coefficient of the silver surface high energy area is reduced, and the method specifically comprises the following steps:

1. placing the silver substrate in a vacuum evaporation system, and vacuumizing to 10 DEG^-4Pa vacuum degree;

2. shielding the silver substrate by using a baffle, opening an NPB beam source baffle, electrifying the NPB beam source, and heating the beam source to 450-500 ℃;

3. measuring the thermal evaporation speed of NPB molecules, and controlling the numerical value to

A range;

4. opening a silver substrate baffle, and evaporating an NPB film for 4-40 s;

5. and disconnecting the current of the NPB beam source, and taking out the silver substrate after the temperature is reduced to the room temperature.

The secondary electron emission coefficient of the prepared NPB thin-film silver sample wafer was measured by a bias current method, and the measurement results are shown in FIG. 1. As shown in FIG. 1, the NPB film with the thickness of 20nm can greatly reduce the secondary electron emission coefficient of silver in the energy range of more than or equal to 250 eV. Therefore, the NPB film provided by the invention can greatly reduce the secondary electron emission coefficient of the high-energy area of the silver substrate, and the maximum reduction amplitude at 1300eV is 38%. The NPB coating and the silver sheet have good compatibility, and the NPB coating is uniformly distributed on the surface of the silver sheet and does not fall off or peel.