CN213150711U - Internal heating type LaB6 cathode - Google Patents
Internal heating type LaB6 cathode Download PDFInfo
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- CN213150711U CN213150711U CN202022340592.5U CN202022340592U CN213150711U CN 213150711 U CN213150711 U CN 213150711U CN 202022340592 U CN202022340592 U CN 202022340592U CN 213150711 U CN213150711 U CN 213150711U
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Abstract
The utility model discloses an internal heating type LaB6 cathode, which comprises a LaB6 emitter, a heater, a heating electrode and a cathode base, wherein the bottom end of the heating electrode vertically penetrates through the cathode base through a mounting hole reserved on the cathode base, and the cathode base is in a structural form with a small top and a big bottom; the diameter of the top end of the heating electrode is larger than that of the lower end of the heating electrode, a thermion clamping groove is formed in the top of the heating electrode, and the thermion is vertically inserted into the clamping groove; the bottom of the LaB6 emitter is provided with a groove, a small groove matched with the size of the thermion is arranged in the groove, and the top end of the thermion is matched with the small groove arranged on the LaB6 emitter; the LaB6 projectile was provided with a raised structure on the outside for mounting a heat shield. The LaB6 emitter is designed into a hollow structure, a high-resistance graphite thermion is arranged in the emitter, a heating mode of heat conduction and heat radiation is formed from the inside, the heat shield structure greatly improves the heating efficiency and reduces the loss, and the structure is suitable for the emitter with the diameter of 3-15 mm.
Description
Technical Field
The utility model relates to a cathode electron source, concretely relates to internal heating formula LaB6 negative pole.
Background
At present, in many large-scale equipment for dynamic vacuum electron beam processing, material processing, detection and analysis, and scientific research, a cathode electron source capable of normally working after repeatedly exposing to the atmosphere needs to be used, and cathodes satisfying such conditions are few, and tungsten, molybdenum, tantalum, and LaB6 cathodes are commonly used. Among these cathodes, LaB6 cathode has the most excellent performance, mainly comprising:
1. the work function is low (2.4-2.8eV), the emission current density is high (under normal working temperature, the direct current emission is tens of times of tungsten and molybdenum);
2. the vapor pressure is extremely low and is far lower than that of refractory metal materials such as tungsten, molybdenum and the like, so that the pollution to a vacuum system is avoided;
3. strong resistance to poisoning and ion bombardment;
4. has high chemical stability, and the emitting performance is unchanged after the coating is repeatedly exposed to the atmosphere at normal temperature.
The normal working temperature of the hot cathode made of LaB6 is 1400 ℃ and 1600 ℃, and the working life reaches 1000 hours. However, compared with tungsten-molybdenum cathodes, LaB6 cathodes are difficult to manufacture, mainly due to the following:
1: the resistivity of the LaB6 cathode is very small, and a direct electrifying heating mode is difficult to adopt;
2: LaB6 reacts with the base layer metal material at high temperature to destroy the material structure, resulting in cathode damage.
SUMMERY OF THE UTILITY MODEL
The technical problem to be solved by the present invention is indirect heating of LaB6 cathode, and the thermal chemical reaction between LaB6 and the basal metal layer at high temperature results in cathode damage, and the object is to provide an internal heating LaB6 cathode for solving the above problems.
The utility model discloses a following technical scheme realizes:
an internal heating type LaB6 cathode comprises a LaB6 emitter, a heater, a heating electrode and a cathode base, wherein the bottom end of the heating electrode vertically penetrates through the cathode base through a mounting hole reserved in the cathode base, and the cathode base is in a structural form with a small top and a big bottom; the diameter of the top end of the heating electrode is larger than that of the lower end of the heating electrode, a heater clamping groove is formed in the top of the heating electrode, and the heater is vertically inserted into the clamping groove; the bottom of the LaB6 emitter is provided with a groove, a small groove matched with the size of the thermion is arranged in the groove, and the top end of the thermion is matched with the small groove arranged on the LaB6 emitter; and a convex structure is arranged outside the LaB6 emitter. The LaB6 emitter is designed into a hollow structure, and a thermion (high-resistance graphite) is arranged in the emitter, so that a heating mode of heat conduction and heat radiation is formed from the inside, the heating efficiency is greatly improved, and the structure is suitable for the emitter with the diameter of 3-15 mm.
The further technical scheme is as follows:
the clamping ring a, the heat shielding ring and the clamping ring b are sequentially arranged from bottom to top; the heat shielding ring, the clamping ring a, the clamping ring b and the heating electrode are coaxial; the lower bottom surface of the clamping ring a is in line connection with the top surface of the cathode base, and the heat shield structure isolates heat generated by the heating electrode, so that a thermochemical reaction between metals is avoided.
Further: the ceramic beads are of cylindrical structures and are provided with through holes with sizes matched with those of the heating electrodes; the bottom surface is connected with the top surface of snap ring b under the porcelain pearl, and the porcelain pearl possess good heat-proof quality and heat insulating ability can promote heating efficiency.
Further: the outer diameters of the porcelain beads, the snap ring b, the heat shielding ring and the snap ring a are equal; the inner side of the lower end of the cathode cylinder is connected with the outer side of the upper part of the cathode base, and the bottom surface of the cathode cylinder is connected with the top surface of the lower part of the cathode base; the outer side of the lower end of the cathode cylinder is provided with an annular structure with a trapezoidal section, the inner side of the upper end of the cathode cylinder is provided with a protruding structure at a height matched with the porcelain beads, and an exhaust hole is formed above the protruding structure. Wherein the snap ring structure plays the effect of connecting and limiting position, and the exhaust hole is used for getting rid of the pressure in the heating chamber, keeps high vacuum, avoids causing the damage to the cathode structure because vacuum is low.
Further: the size of the isolation ring is matched with the protruding structure on the outer side of the LaB6 emitter, the outer diameter of the isolation ring is in a structural form with a small upper part and a large lower part, the inner side of the isolation ring is attached to the outer side of the LaB6 emitter, the outer side of the isolation ring is attached to the inner side of the cathode cylinder, the ground of the isolation ring is connected with the protruding structure, and the top surface of the isolation ring is coplanar with the top surface of the LaB6 emitter; the size of the cathode head hoop is matched with the isolating ring and the cathode cylinder, the inner diameter of the cathode head hoop is in a structural form of being large at the top and small at the bottom, the upper part of the cathode head hoop is attached to the upper part of the isolating ring, and the inner side of the lower part of the cathode head hoop is attached to the outer side of the cathode cylinder. The LaB6 emitter is separated from the cathode head band by a separating ring made of high-purity graphite, so that the problem of thermochemical reaction at high temperature is solved.
Further: the first heat shield is connected with the lower protruding structure of the cathode cylinder, a gap exists between the first heat shield and the cathode cylinder, and a gap exists between the top of the first heat shield and the bottom of the cathode head hoop; the second heat shield is connected with the lower protruding structure of the cathode cylinder, and a gap exists between the second heat shield and the first heat shield as well as between the second heat shield and the cathode head hoop. The heat shielding cover is added on the outer side and the lower part of the cathode cylinder, so that the heat radiation energy loss of the thermions and the emitter is greatly reduced, the heating efficiency is improved, and the energy consumption is reduced.
Further: the above-mentioned
Compared with the prior art, the utility model, following advantage and beneficial effect have:
1. the utility model relates to an internal heating type LaB6 cathode, in the structure, the LaB6 emitter is designed into a hollow structure, and a heater made of high resistance graphite is arranged in the emitter, so that a heating mode of heat conduction and heat radiation is formed from the inside, and the heating efficiency is greatly improved;
2. the utility model relates to an internally heated LaB6 cathode, in the structure, the outer side of the upper part of a LaB6 emitter isolates the LaB6 emitter from a cathode head hoop by using an isolating ring made of high-purity graphite, thereby solving the problem of thermochemical reaction at high temperature;
3. the utility model relates to an internal heating LaB6 cathode, in the structure, a heat shield structure is added at the outer side and the lower part of a cathode tube, thereby greatly reducing the heat radiation energy loss of a heater and an emitter, improving the heating efficiency and reducing the energy consumption;
4. the utility model relates to an internal heating type LaB6 cathode, which is suitable for a large-area emitter with the diameter of 3-15 mm.
Drawings
The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention. In the drawings:
fig. 1 is a schematic structural diagram of the present invention.
Fig. 2 is a top view of the present invention.
Reference numbers and corresponding part names in the drawings:
1-LaB6 emitter, 2-spacer ring, 3-cathode head hoop, 4-cathode cylinder, 5-heater, 6-heating electrode, 7-ceramic bead, 8-first heat shield, 9-second heat shield, 10-heat shield, 11-snap ring a, 12-cathode base, 13-snap ring b, 14-exhaust hole.
Detailed Description
To make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the following examples and drawings, and the exemplary embodiments and descriptions thereof of the present invention are only used for explaining the present invention, and are not intended as limitations of the present invention.
Example 1:
as shown in fig. 1 or fig. 2, an internally heated LaB6 cathode includes a LaB6 emitter 1, a heater 5, a heater electrode 6 and a cathode base 12, wherein the bottom end of the heater electrode 6 vertically penetrates through the cathode base 12 through a mounting hole reserved on the cathode base 12, and the cathode base 12 has a structure form with a small top and a large bottom; the diameter of the top end of the heating electrode 6 is larger than that of the lower end of the heating electrode, a heater 5 clamping groove is formed in the top of the heating electrode, and the heater 5 is vertically inserted into the clamping groove; the bottom of the LaB6 emitter 1 is provided with a groove, a small groove matched with the size of the thermite 5 is arranged in the groove, and the top end of the thermite 5 is matched with the small groove arranged on the LaB6 emitter 1; and a convex structure is arranged outside the LaB6 emitter 1.
Example 2:
as shown in fig. 1 or fig. 2, the snap ring a11, the heat shield ring 10 and the snap ring b13 are arranged from bottom to top in sequence; the heat shield ring 10, the snap ring a11, the snap ring b13 and the heating electrode 6 are coaxial; the lower bottom surface of the snap ring a11 is connected with the top surface of the cathode base 12 by a wire; the ceramic beads 7 are of cylindrical structures and are provided with through holes with sizes matched with those of the heating electrodes 6; the lower bottom surface of the porcelain bead 7 is connected with the top surface of the snap ring b 13; the porcelain beads 7, the snap ring b13, the heat shield ring 10 and the snap ring a11 have the same outer diameter.
The inner side of the lower end of the cathode cylinder 4 is connected with the outer side of the upper part of the cathode base 12, and the bottom surface of the cathode cylinder 4 is connected with the top surface of the lower part of the cathode base 12; the outer side of the lower end of the cathode cylinder 4 is provided with an annular structure with a trapezoidal section, the inner side of the upper end is provided with a convex structure at the height matched with the porcelain beads 7, and an exhaust hole 14 is arranged above the convex structure.
The size of the isolation ring 2 is matched with the convex structure on the outer side of the LaB6 emitter, the outer diameter of the isolation ring is in a structural form with a small upper part and a large lower part, the inner side of the isolation ring 2 is attached to the outer side of the LaB6 emitter 1, the outer side of the isolation ring 2 is attached to the inner side of the cathode barrel 4, the ground of the isolation ring 2 is connected with the convex structure, and the top surface of the isolation ring 2 is coplanar with the top surface of the LaB6 emitter 1; the size of the cathode head hoop 3 is matched with the isolating ring 2 and the cathode cylinder 4, the inner diameter of the cathode head hoop is in a structural form with a large upper part and a small lower part, the upper part of the cathode head hoop 3 is attached to the upper part of the isolating ring 2, and the inner side of the lower part of the cathode head hoop 3 is attached to the outer side of the cathode cylinder 4.
The first heat shield 8 is connected with the lower protruding structure of the cathode cylinder 4, and the first heat shield 8 has a gap with the cathode cylinder 4, and the top of the first heat shield 8 has a gap with the bottom of the cathode head hoop 3; the second heat shield 9 is connected with the lower convex structure of the cathode cylinder 4, and a gap exists between the second heat shield 9, the first heat shield 8 and the cathode head hoop 3.
The above-mentioned embodiments, further detailed description of the objects, technical solutions and advantages of the present invention, it should be understood that the above description is only the embodiments of the present invention, and is not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (7)
1. The internally heated LaB6 cathode is characterized by comprising a LaB6 emitter (1), a heater (5), a heating electrode (6) and a cathode base (12), wherein the bottom end of the heating electrode (6) vertically penetrates through the cathode base (12) through a mounting hole reserved in the cathode base (12), and the cathode base (12) is in a structural form with a small top and a large bottom;
the diameter of the top end of the heating electrode (6) is larger than that of the lower end of the heating electrode, a heater (5) clamping groove is formed in the top of the heating electrode, and the heater (5) is vertically inserted into the clamping groove;
the bottom of the LaB6 emitter (1) is provided with a groove, a small groove matched with the heater (5) in size is formed in the groove, and the top end of the heater (5) is matched with the small groove formed in the LaB6 emitter (1);
and a convex structure is arranged on the outer side of the LaB6 emitter (1).
2. The internally heated LaB6 cathode according to claim 1, further comprising a heat shield ring (10), a snap ring a (11) and a snap ring b (13), wherein the snap ring a (11), the heat shield ring (10) and the snap ring b (13) are arranged from bottom to top in sequence;
the heat shielding ring (10), the clamping ring a (11), the clamping ring b (13) and the heating electrode (6) are coaxial;
the lower bottom surface of the snap ring a (11) is connected with the top surface line of the cathode base (12).
3. The internally heated LaB6 cathode according to claim 2, further comprising ceramic beads (7), wherein the ceramic beads (7) are cylindrical structures and are provided with through holes corresponding to the size of the heating electrodes (6);
the lower bottom surface of the porcelain bead (7) is connected with the top surface of the snap ring b (13).
4. An internally heated LaB6 cathode according to claim 3, wherein the ceramic beads (7), the retaining ring b (13), the heat shield ring (10) and the retaining ring a (11) have the same outer diameter.
5. The internally heated LaB6 cathode according to claim 1, further comprising a cathode cylinder (4), wherein the inside of the lower end of the cathode cylinder (4) is connected with the outside of the upper part of the cathode base (12), and the bottom surface of the cathode cylinder (4) is connected with the top surface of the lower part of the cathode base (12);
the outer side of the lower end of the cathode cylinder (4) is provided with an annular structure with a trapezoidal section, the inner side of the upper end of the cathode cylinder is provided with a convex structure at the height matched with the porcelain beads (7), and an exhaust hole (14) is arranged above the convex structure.
6. The internally heated LaB6 cathode according to claim 1, further comprising a spacer ring (2) and a cathode head band (3), wherein the size of the spacer ring (2) is adapted to the protruding structure outside the LaB6 emitter (1), and the outer diameter of the spacer ring is in a structure form with a small top and a large bottom, the inner side of the spacer ring (2) is attached to the outer side of the LaB6 emitter (1), the outer side of the spacer ring (2) is attached to the inner side of the cathode tube (4), and the ground of the spacer ring (2) is connected to the protruding structure, the top surface of the spacer ring (2) is coplanar with the top surface of the LaB6 emitter (1);
the size of the cathode head hoop (3) is matched with the isolating ring (2) and the cathode cylinder (4), the inner diameter of the cathode head hoop is in a structural form of big end up, the upper part of the cathode head hoop (3) is attached to the upper part of the isolating ring (2), and the lower part of the cathode head hoop (3) is attached to the outer side of the cathode cylinder (4).
7. The internally heated LaB6 cathode according to claim 1, further comprising a first heat shield (8) and a second heat shield (9), wherein the first heat shield (8) is connected to the lower protruding structure of the cathode can (4), and the first heat shield (8) has a gap with the cathode can (4), and the top of the first heat shield (8) has a gap with the bottom of the cathode head band (3);
the second heat shield (9) is connected with the lower protruding structure of the cathode cylinder (4), and a gap exists between the second heat shield (9) and the first heat shield (8) and between the second heat shield and the cathode head hoop (3).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022340592.5U CN213150711U (en) | 2020-10-20 | 2020-10-20 | Internal heating type LaB6 cathode |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022340592.5U CN213150711U (en) | 2020-10-20 | 2020-10-20 | Internal heating type LaB6 cathode |
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| Publication Number | Publication Date |
|---|---|
| CN213150711U true CN213150711U (en) | 2021-05-07 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202022340592.5U Active CN213150711U (en) | 2020-10-20 | 2020-10-20 | Internal heating type LaB6 cathode |
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|---|---|
| CN (1) | CN213150711U (en) |
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