An electromagnetic diagnostic probe for fusion reactor environment and a manufacturing method thereof

Abstract

This invention discloses an electromagnetic diagnostic probe and its fabrication method for fusion reactor environments, belonging to the field of manufacturing technology for electromagnetic measurement and diagnostic components for tokamak and fusion reactors. The probe includes an integrated low-temperature co-fired ceramic (LTCC) magnetic induction core, an alumina ceramic protective plate disposed on the outside of the magnetic induction core, a foamed copper buffer heat-conducting layer, and a 316L stainless steel probe box. The magnetic induction core includes a first-layer electrode and heat dissipation layer, 30 induction layers, and a final-layer electrode and heat dissipation layer. Racetrack-shaped conductor coils are formed within the induction layers through thick-film printing and connected in series via interlayer vias. The first and final layers are decorated with nickel-gold plated silver paste for heat dissipation and shielding. After isostatic pressing in warm water, glue removal, co-firing at approximately 850°C, surface chemical plating with nickel and gold, and electrical performance screening, an inorganic insulating integrated structure with a thickness of approximately 4 mm is formed. This invention reduces the risks of winding, insulation damage, and lead wire brazing failure under high-temperature vacuum and irradiation environments.

Description

Technical Field

[0001] This invention belongs to the field of manufacturing technology of electromagnetic measurement and diagnostic components for tokamak and fusion reactors. Specifically, it relates to an electromagnetic diagnostic probe and its manufacturing method for fusion reactor environments, which is suitable for measuring magnetic field changes under high temperature, vacuum, strong electromagnetic disturbance, and neutron and nuclear irradiation coupling environments. Background Technology

[0002] Electromagnetic probes typically utilize the principle of electromagnetic induction to acquire local magnetic field changes, and then integrate or calibrate to reconstruct the magnetic field information. Their output can be used for plasma equilibrium inversion, magnetohydrodynamic instability analysis, boundary control, and device protection. Common magnetic probes used in existing tokamak devices include PTFE-insulated cable winding structures, mineral-insulated armored wire winding structures, and ceramic-based printed coil structures. Among these, published literature has proposed and verified that LTCC (Low Temperature Co-fired Ceramic) multilayer ceramic magnetic sensors can be used for magnetic diagnostics in tokamak devices such as ITER (International Thermonuclear Experimental Reactor) and TCV (Variable Configuration Tokamak). Therefore, this invention should not only distinguish itself by "using LTCC," but should highlight the specific multilayer coil, heat dissipation and shielding, buffer protection, and housing fixing combination suitable for the installation space and service load of this device.

[0003] In summary, existing tokamak electromagnetic probes still have the following issues that require further improvement:

[0004] 1. Insufficient adaptability of materials and assembly: Organic insulating materials are at risk of gas leakage, aging and activation under high temperature vacuum and irradiation environments; armored wire or fine wire winding structures are prone to insulation weaknesses at multi-layer tight winding, local bending and lead wire connection points.

[0005] 2. Insufficient structural consistency and detectability: Wire-wound probes rely on manual winding, assembly and brazing, and it is difficult to ensure the consistency of coil turn position, tension, interlayer spacing and solder joint condition; the complex small-size structure also increases the difficulty of non-destructive testing and batch consistency control.

[0006] 3. Insufficient control of thermal noise and thermoelectric potential: There are heat flow, radio frequency bombardment and electromagnetic transient loads inside the fusion device. If the thermal contact between the coil, solder joint, lead and mounting box is uneven, temperature gradient and thermoelectric potential drift are likely to occur, affecting the stability of the integral signal baseline. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides an electromagnetic diagnostic probe and its fabrication method for fusion reactor environments. The probe uses a multilayer LTCC co-fired magnetic induction core instead of PTFE cable or armored wire winding structures, and employs a racetrack-shaped thick-film conductor coil to achieve a larger equivalent induction area. The probe reduces the impact of radio frequency bombardment, local thermal gradients, and assembly stress through nickel-gold plating on the first and last layers for heat dissipation and shielding, an alumina ceramic protective plate, and a foamed copper buffer thermal conductive layer. Mechanical fixation and signal extraction under high-temperature vacuum environments are achieved through a 316L stainless steel probe box, screw fixing structure, and ceramic terminals. The probe includes an integrated low-temperature co-fired ceramic (LTCC) magnetic induction core, an alumina ceramic protective plate disposed on the outside of the magnetic induction core, a foamed copper buffer thermal conductive layer, and a 316L stainless steel probe box. The magnetic induction core includes a first-layer electrode and heat dissipation layer, 30 induction layers, and a last-layer electrode and heat dissipation layer. A racetrack-shaped conductor coil is formed within the induction layer through thick-film printing and connected in series via interlayer vias. The first and last layers are provided with nickel-gold plating silver paste for heat dissipation and shielding. After isostatic pressing in warm water, glue removal, co-firing at around 850℃, surface electroless nickel and gold plating, and electrical performance screening, an inorganic insulating integrated structure with a thickness of approximately 4mm is formed. Compared with probes wound with PTFE cables or armored wires, this invention reduces the risks of winding, insulation damage, and lead wire brazing failure under high temperature vacuum and irradiation environments, and can obtain a larger equivalent sensing area in a confined space.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] An electromagnetic diagnostic probe for fusion reactor environments includes a low-temperature co-fired ceramic (LTCC) core, an alumina ceramic protective plate, a copper foam buffer thermal conductive layer, a 316L stainless steel probe box, and radiation-resistant leads. The LTCC core is a single structure formed by stacking and co-firing a first-layer electrode and a heat dissipation layer, 30 induction layers, and a final-layer electrode and heat dissipation layer. Each induction layer contains a racetrack-shaped conductor coil formed by thick-film printing and connected in series through interlayer vias. The outer surfaces of the first-layer electrode and the heat dissipation layer, as well as the final-layer electrode and the heat dissipation layer, are all covered with a nickel-gold plated silver paste heat dissipation shielding pattern. The alumina ceramic protective plate covers the heated side surface of the LTCC core. The copper foam buffer thermal conductive layer is disposed between the LTCC core and the 316L stainless steel probe box or between the LTCC core and the alumina ceramic protective plate. The 316L stainless steel probe box is connected to the LTCC core via screw fixing and fitting with fixing holes on the LTCC core to encapsulate the LTCC core. The radiation-resistant leads are electrically connected to the nickel-gold plated silver paste heat dissipation shielding pattern. LTCC stands for Low-Temperature Co-Fired Ceramic.

[0010] Furthermore, the total thickness of the 30 sensing layers is 3mm, the thickness of a single sensing layer is 0.08mm to 0.12mm, the thickness of the first electrode and heat dissipation layer and the last electrode and heat dissipation layer is 0.4mm to 0.6mm, and the total thickness of the LTCC magnetic induction core after forming is 3.5mm to 4.5mm.

[0011] Furthermore, each layer of racetrack-shaped conductor coil has 14 to 15 turns, and the conductor thickness formed after sintering is 10 μm to 14 μm, the conductor width is 0.5 mm, the spacing between adjacent conductors is 0.3 mm, and the diameter of the interlayer through-hole is 0.25 mm to 0.35 mm and the inside is filled with conductor paste.

[0012] Furthermore, the radiation-resistant lead is a glass fiber insulated cable or a mica insulated cable. The radiation-resistant lead is connected to the nickel-gold plated silver paste heat dissipation shielding pattern by laser welding, resistance welding or high-temperature brazing, and the signal is led out through ceramic terminals.

[0013] Furthermore, the 316L stainless steel probe box is equipped with a probe receiving groove that matches the shape of the LTCC magnetic induction core. The bottom or side wall of the probe receiving groove is equipped with screw fixing holes corresponding to the fixing holes and a lead wire channel for the radiation-resistant lead wire to pass through. The alumina ceramic protection plate is located on the side of the LTCC magnetic induction core closer to the plasma and is clamped and positioned by the screw fixing structure.

[0014] This invention also provides a method for manufacturing the aforementioned electromagnetic diagnostic probe for fusion reactor environments, comprising: forming interlayer vias on LTCC green ceramic tape and filling them with conductive paste; printing racetrack-shaped conductor coils on the induction layer green ceramic tape using thick film printing technology and printing electrode heat dissipation patterns on the first and last green ceramic tapes; aligning and stacking the printed green ceramic tapes in the order of the first electrode and heat dissipation layer, 30 induction layers, and the last electrode and heat dissipation layer; isostatically pressing with warm water and then cutting into single-piece semi-finished products; removing adhesive and co-firing at 830°C to 870°C to form an LTCC magnetic induction core; chemically plating nickel-gold onto the exposed electrodes and heat dissipation shielding patterns; performing electrical performance screening and non-destructive testing after nickel-gold plating; and installing the LTCC magnetic induction core, foamed copper buffer thermal conductive layer, and alumina ceramic protective plate into a 316L stainless steel probe box and fixing it, and performing quality consistency inspection.

[0015] Furthermore, the isostatic pressure of the warm water is 180 kg / cm². 2 Up to 230kg / cm 2 The peak temperature of co-firing is 830℃ to 870℃, and a debinding stage is set during the heating process to remove organic matter from the green ceramic belt.

[0016] Furthermore, nondestructive testing employs X-ray or CT scans to confirm the alignment accuracy between layers, the continuity of the racetrack-shaped conductor coil, the filling status of interlayer vias, and whether delamination or crack defects exist after co-firing.

[0017] Furthermore, the qualification criteria for electrical performance screening are a DC resistance of not more than 120Ω and an insulation resistance of more than 1GΩ at 200V.

[0018] Furthermore, the quality consistency inspection items include dimensions, DC resistance, insulation resistance, withstand voltage, thermal cycling, leakage rate after vacuum baking, solder joint strength, and consistency of calibration coefficients.

[0019] Beneficial effects:

[0020] 1. The main insulation and support structure of this invention uses inorganic and metallic materials such as LTCC, alumina ceramic, copper foam, and 316L stainless steel to reduce the risk of organic matter escaping and thermal aging; after assembly, it can be baked at 500℃ with a vacuum leakage rate of no more than 10%. -8 Pa·m 3 The results were verified using metrics such as / s and cumulative neutron flux.

[0021] 2. The 30-layer racetrack-shaped coils of this invention, when connected in series, can form a diameter greater than 0.25m. 2 The equivalent induction area is no more than 120Ω DC resistance and the insulation resistance is greater than 1GΩ at 200V; the thermal gradient is reduced by the heat dissipation of the first and last layers, the shielding pattern and the thermally conductive buffer layer of foam copper, thereby reducing the risk of thermoelectric potential drift.

[0022] 3. The multilayer LTCC stacked co-fired structure of the present invention improves the geometric consistency of the coil and reduces the steps of manual winding and fine wire brazing; combined with X-ray and CT, resistance, insulation and size screening, it can improve batch consistency. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the LTCC magnetic induction core forming structure of the electromagnetic diagnostic probe for fusion reactor environments according to the present invention.

[0024] Figures 2(a)-2(j) are schematic diagrams of the layered structure of the LTCC magnetic induction core of the present invention, wherein Figure 2(a) is the first layer electrode and heat dissipation layer, Figure 2(b) is the racetrack-shaped conductor coil in the induction layer, Figure 2(c) is the last layer electrode and heat dissipation layer, Figure 2(d) is the intermediate layer structure of the 4th, 10th, 16th, 22nd and 28th induction layers, Figure 2(e) is the intermediate layer structure of the 5th, 11th, 17th, 23rd and 29th induction layers, Figure 2(f) is the intermediate layer structure of the 6th, 12th, 18th, 24th and 30th induction layers, Figure 2(g) is the intermediate layer structure of the 7th, 13th, 19th and 25th induction layers, Figure 2(h) is the intermediate layer structure of the 8th, 14th, 20th and 26th induction layers, Figure 2(i) is the structure of the last layer induction layer; and Figure 2(j) is the structure of the last layer electrode and heat dissipation layer of the LTCC.

[0025] Figure 3 This is a schematic diagram of the structure of the 316L stainless steel probe box of the present invention;

[0026] Figure 4 A schematic diagram of the structure after assembling the LTCC magnetic induction core, alumina ceramic protective plate, foamed copper buffer thermal conductive layer and 316L stainless steel probe box.

[0027] The attached figures are labeled as follows: 1-LTCC magnetic induction core; 2-first layer electrode and heat dissipation layer; 3-racetrack-shaped conductor coil; 4-interlayer through hole; 5-fixing hole; 6-last layer electrode and heat dissipation layer; 7-alumina ceramic protective plate; 8-foamed copper buffer thermal conductive layer; 9-316L stainless steel probe box; 10-screw fixing structure; 11-radiation resistant lead wire; 12-ceramic terminal block. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0029] like Figures 1 to 4As shown, the electromagnetic diagnostic probe for fusion reactor environments of the present invention includes an LTCC magnetic induction core 1, an alumina ceramic protective plate 7, a copper foam buffer thermal conductive layer 8, a 316L stainless steel probe box 9, radiation-resistant leads 11, and ceramic terminals 12. The LTCC magnetic induction core 1 is formed from multiple layers of LTCC green ceramic tape through thick-film printing, lamination, isostatic pressing, and co-firing. Its internal racetrack-shaped conductor coil 3 is used to sense local magnetic field changes. The two ends of the racetrack-shaped conductor coil 3 are led out through electrodes and a heat dissipation layer and connected to the radiation-resistant leads 11. The LTCC magnetic induction core 1 is encapsulated within the 316L stainless steel probe box 9. The alumina ceramic protective plate 7 covers the heated and irradiated sides of the LTCC magnetic induction core 1. The copper foam buffer thermal conductive layer 8 is located between the LTCC magnetic induction core 1 and the 316L stainless steel probe box 9 or the alumina ceramic protective plate 7, serving to buffer assembly stress and form a heat-conducting channel.

[0030] Figure 2(a) shows the first layer electrode and heat dissipation layer; Figure 2(b) shows the racetrack-shaped conductor coil in the induction layer; Figure 2(c) shows the last layer electrode and heat dissipation layer; Figure 2(d) shows the intermediate layer structure of the 4th, 10th, 16th, 22nd, and 28th induction layers; Figure 2(e) shows the intermediate layer structure of the 5th, 11th, 17th, 23rd, and 29th induction layers; Figure 2(f) shows the intermediate layer structure of the 6th, 12th, 18th, 24th, and 30th induction layers; Figure 2(g) shows the intermediate layer structure of the 7th, 13th, 19th, and 25th induction layers; Figure 2(h) shows the intermediate layer structure of the 8th, 14th, 20th, and 26th induction layers; Figure 2(i) shows the structure of the last layer induction layer; and Figure 2(j) shows the structure of the last layer electrode and heat dissipation layer of the LTCC.

[0031] The LTCC magnetic induction core 1 is a rectangular plate structure, with its thickness direction consisting of a first electrode and heat dissipation layer 2, a 30-layer induction layer, and a final electrode and heat dissipation layer 6. Two fixing holes 5 are spaced apart in the middle of the core and are opposite to the screw fixing structure 10 inside the 316L stainless steel probe box 9. An alumina ceramic protective plate 7 covers the side of the LTCC magnetic induction core 1 closest to the plasma or thermal load. A foamed copper buffer thermal conductive layer 8 is disposed between the LTCC magnetic induction core 1 and the 316L stainless steel probe box 9 or the alumina ceramic protective plate 7 to compensate for assembly gaps, buffer thermal stress, and enhance heat conduction.

[0032] Preferably, the LTCC magnetic induction core 1 is made of low-temperature co-fired ceramic green ceramic strip. Laser drilling, through-hole filling, thick-film printing of conductor patterns, and drying are performed on the low-temperature co-fired ceramic green ceramic strip. The green ceramic strips with printed conductor patterns are then stacked in sequence and subjected to processes such as warm water isostatic pressing, cutting, glue removal, sintering, chemical nickel and gold plating, and screening and testing to form a multi-layered integrated ceramic structure.

[0033] Preferably, the LTCC magnetic induction core 1 is a rectangular plate with a stacked structure including a first electrode and heat dissipation layer 2, 30 induction layers, and a last electrode and heat dissipation layer 6. The total thickness of the induction layer is 3 mm and is formed by stacking and co-firing 30 layers of LTCC green ceramic tape with a thickness of approximately 0.10 mm. After forming, the total thickness of the core is approximately 4 mm. The thickness of a single induction layer is 0.08 mm to 0.12 mm, preferably 0.10 mm, and the thickness of a single layer of the first electrode and heat dissipation layer 2 and the last electrode and heat dissipation layer 6 is 0.4 mm to 0.6 mm, preferably 0.5 mm.

[0034] Preferably, the conductor pattern on each induction layer is a racetrack-shaped conductor coil 3, preferably formed by thick film printing of silver paste. Alternatively, silver-palladium, platinum, or palladium-based conductor pastes can be selected depending on the neutron irradiation and activation requirements. Each racetrack-shaped conductor coil 3 has 14-15 turns, with a conductor thickness of 10μm-14μm, a conductor width of approximately 0.5mm, and a spacing of approximately 0.3mm between adjacent conductors after sintering. The outer surfaces of the first electrode and heat dissipation layer 2, and the last electrode and heat dissipation layer 6 are printed with silver paste heat dissipation and shielding patterns and plated with nickel-gold to improve welding reliability, oxidation resistance, and heat diffusion capability. The 30-layer racetrack-shaped conductor coils 3 are connected in series through interlayer vias 4 filled with conductor paste. The diameter of the interlayer vias 4 is 0.25mm-0.35mm, preferably 0.30mm.

[0035] Preferably, the surfaces of the first electrode and heat dissipation layer 2 and the last electrode and heat dissipation layer 6 are provided with nickel-gold plated silver paste patterns, which also serve as electrode pads, heat dissipation layers and radio frequency bombardment shielding layers; the LTCC magnetic induction core 1 is provided with two fixing holes 5, which cooperate with the screw fixing structure of the 316L stainless steel probe box 9.

[0036] Preferably, the radiation-resistant lead 11 is a high-temperature and radiation-resistant glass fiber insulated cable or a mica insulated cable. The radiation-resistant lead 11 is connected to the nickel-gold plated silver paste electrode by laser welding, resistance welding or high-temperature brazing, and is led out through the ceramic terminal 12.

[0037] Preferably, the overall dimensions of the LTCC magnetic induction core 1 are 40mm-50mm in length, 30mm-40mm in width, and 3.5mm-4.5mm in thickness, preferably 45mm×35mm×4mm; the equivalent induction area of ​​the probe is greater than 0.25m². 2 The DC resistance is not greater than 120Ω, and the insulation resistance at 200V is greater than 1GΩ.

[0038] Preferably, the electromagnetic diagnostic probe, after assembly, meets the requirement that the vacuum leakage rate is no greater than 10%. -8 Pa·m 3 / s, and can withstand baking or operating temperatures of not less than 500℃; the neutron irradiation capability is characterized by the cumulative neutron flux.

[0039] This invention improves high-temperature resistance, vacuum resistance, and radiation resistance through inorganic insulation and metal encapsulation structures; its equivalent sensing area can be greater than 0.25m². 2 The high-frequency response specifications, once calibrated, can meet the target frequency band, for example, not lower than 50kHz.

[0040] The present invention also provides a method for fabricating the above-mentioned electromagnetic diagnostic probe for fusion reactor environments, comprising the following steps:

[0041] Step 1, Opening and Filling: Using a laser, interlayer through-holes 4 are formed on the LTCC green ceramic tape. The diameter of the through-holes is preferably 0.30 mm. Then, the through-holes are filled with conductive paste so that a series circuit can be formed between adjacent sensing layers.

[0042] Step 2, Printing: Using thick film printing technology, a racetrack-shaped conductor coil 3 is printed on the green ceramic tape of the induction layer and dried. The thickness of the conductor paste after sintering is 10μm to 14μm. Electrodes and heat dissipation patterns are printed on the first and last green ceramic tapes.

[0043] Step 3, Stacking: The printed green ceramic tapes are aligned and stacked in the order of the first electrode and heat dissipation layer 2, the 30th induction layer, and the last electrode and heat dissipation layer 6, so that the racetrack-shaped conductor coils 3 of each layer are connected in series through the interlayer through-holes 4.

[0044] Step 4, Warm Water Isostatic Pressing: After vacuum sealing the stacked product panels, place them in a warm water isostatic press at 180 kg / cm². 2 ~230kg / cm 2 Optimal 210kg / cm 2 Compacted under pressure to reduce the risk of delamination during subsequent cutting and sintering.

[0045] Step 5, Cutting: Cut to the set size to form a single semi-finished product, and expose the electrode lead-out area; the dimensional tolerance after cutting is controlled within ±0.1mm.

[0046] Step 6, Debinding and Sintering: Place the cut single-piece semi-finished product in a sintering furnace, and debind the organic matter according to the set heating curve. Then, co-fire it into a dense ceramic body at a peak temperature of 830℃~870℃, preferably 850℃.

[0047] Step 7, Electroless nickel and gold plating: Form nickel and gold layers on the exposed electrodes and the surfaces of the heat dissipation and shielding patterns to improve solderability, oxidation resistance and thermal cycling resistance; the plating thickness should be determined in conjunction with the welding process and vacuum material requirements.

[0048] Step 8, Screening: Screen the products after electroless nickel and gold plating by appearance, size, resistance, insulation resistance and non-destructive testing.

[0049] Step 9: Perform quality consistency inspection after assembly: Install the LTCC magnetic induction core, foamed copper buffer thermal conductive layer, and alumina ceramic protective plate into the 316L stainless steel probe box and fix it; perform quality consistency inspection of Group A and Group B according to the product detailed specifications. Group A represents batch inspection, and Group B represents periodic sampling inspection. The inspection items include at least dimensions, DC resistance, insulation resistance, withstand voltage, thermal cycling, gas venting and leakage after vacuum baking, solder joint pull-out or shear strength, and calibration coefficient consistency.

[0050] Preferably, the isostatic pressure of the warm water is 180 kg / cm². 2 ~230kg / cm 2 The preferred value is 210 kg / cm². 2 The peak temperature of the co-firing is 830℃~870℃, preferably 850℃, and a debinding stage is set during the heating process to remove organic matter from the green ceramic belt.

[0051] Preferably, the X-ray or CT inspection is used to confirm interlayer alignment, conductor continuity, via filling status, and whether there are delamination, cracks, or printing defects after co-firing.

[0052] Preferably, the DC resistance of the electromagnetic diagnostic probe is no greater than 120Ω, and the insulation resistance at 200V is greater than 1GΩ; the above indicators should be retested after welding, packaging and baking.

[0053] Preferably, the electromagnetic diagnostic probe can withstand baking or operating temperatures of not less than 500°C.

[0054] Preferably, the radiation-resistant lead 11 of the electromagnetic diagnostic probe is made of glass fiber insulated cable or mica insulated cable, and the cable is connected to the nickel-gold plated electrode by laser welding, resistance welding or high-temperature brazing.

[0055] Preferably, if ceramic adhesive is to be used in the welding area, inorganic ceramic adhesive or glass sealing material that is compatible with 500°C baking, vacuum venting and irradiation conditions should be used; if the existing ceramic adhesive has a temperature resistance of only 300°C, it should be limited to low-temperature non-critical areas to avoid weakening the overall 500°C performance.

[0056] Preferably, the foamed copper buffer thermal conductive layer 8 is disposed between the LTCC magnetic induction core 1 and the 316L stainless steel probe box 9, or between the alumina ceramic protective plate 7 and the LTCC magnetic induction core 1, to compensate for assembly gaps, buffer screw clamping force and improve thermal contact.

[0057] Preferably, the alumina ceramic protective plate 7 covers the side of the LTCC magnetic induction core 1 closest to the plasma or thermal load, in order to reduce the impact of particle bombardment, radio frequency bombardment and mechanical scratches on the metallization layer of the LTCC surface.

[0058] Preferably, the LTCC surfaces of the first electrode and heat dissipation layer 2, and the last electrode and heat dissipation layer 6 are provided with nickel-gold plated silver paste patterns. The silver paste patterns serve as heat dissipation and shielding layers and pads to enhance heat diffusion, reduce local temperature rise, and reduce the impact of electron cyclotron or other radio frequency wave bombardment on the internal induction coil.

[0059] Preferably, the surface of the final electrode is plated with nickel-gold to improve oxidation resistance, solderability, and contact reliability after thermal cycling.

[0060] like Figure 3 , Figure 4 As shown, the 316L stainless steel probe box 9 has a probe receiving slot that matches the shape of the LTCC magnetic induction core 1. The bottom or side wall of the probe receiving slot has screw fixing holes and lead wire channels. During assembly, first place the foamed copper buffer heat-conducting layer 8 into the probe receiving slot, then place the LTCC magnetic induction core 1 into the probe receiving slot and align the fixing holes 5 with the screw fixing holes; then cover with the alumina ceramic protective plate 7 and press it into position using the screw fixing structure 10; finally, lead the radiation-resistant lead wire 11 along the lead wire channel to the ceramic terminal 12 and complete the connection.

[0061] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An electromagnetic diagnostic probe for fusion reactor environments, characterized in that, The product comprises an LTCC magnetic induction core, an alumina ceramic protective plate, a copper foam buffer thermal conductive layer, a 316L stainless steel probe box, and radiation-resistant leads. The LTCC magnetic induction core is a single structure formed by stacking and co-firing a first-layer electrode and a heat dissipation layer, 30 induction layers, and a final-layer electrode and heat dissipation layer. Each induction layer contains a racetrack-shaped conductor coil formed by thick-film printing and connected in series through interlayer vias. The outer surfaces of the first-layer electrode and heat dissipation layer, as well as the final-layer electrode and heat dissipation layer, are all covered with a nickel-gold plated silver paste heat dissipation shielding pattern. The alumina ceramic protective plate covers the heated side surface of the LTCC magnetic induction core. The copper foam buffer thermal conductive layer is positioned between the LTCC magnetic induction core and the 316L stainless steel probe box, or between the LTCC magnetic induction core and the alumina ceramic protective plate. The 316L stainless steel probe box is connected to the fixing holes on the LTCC magnetic induction core via screw fixing structure to encapsulate the LTCC magnetic induction core. The radiation-resistant leads are electrically connected to the nickel-gold plated silver paste heat dissipation shielding pattern. LTCC stands for Low Temperature Co-fired Ceramic.

2. The electromagnetic diagnostic probe for fusion reactor environments according to claim 1, characterized in that, The total thickness of the 30 sensing layers is 3mm, the thickness of a single sensing layer is 0.08mm to 0.12mm, the thickness of the first electrode and heat dissipation layer and the last electrode and heat dissipation layer is 0.4mm to 0.6mm, and the total thickness of the LTCC magnetic induction core after forming is 3.5mm to 4.5mm.

3. The electromagnetic diagnostic probe for fusion reactor environments according to claim 1, characterized in that, Each layer of racetrack-shaped conductor coil has 14 to 15 turns, and the conductor thickness formed after sintering is 10 μm to 14 μm, the conductor width is 0.5 mm, the spacing between adjacent conductors is 0.3 mm, and the diameter of the interlayer through-hole is 0.25 mm to 0.35 mm and the inside is filled with conductor paste.

4. The electromagnetic diagnostic probe for fusion reactor environments according to claim 1, characterized in that, The radiation-resistant lead is made of glass fiber insulated cable or mica insulated cable. The radiation-resistant lead is connected to the nickel-gold plated silver paste heat dissipation shielding pattern by laser welding, resistance welding or high-temperature brazing, and the signal is led out through ceramic terminals.

5. An electromagnetic diagnostic probe for fusion reactor environments according to claim 1, characterized in that, The 316L stainless steel probe box has a probe receiving slot that matches the shape of the LTCC magnetic induction core. The bottom or side wall of the probe receiving slot has screw fixing holes corresponding to the fixing holes and a lead wire channel for the radiation-resistant lead wire to pass through. The alumina ceramic protection plate is located on the side of the LTCC magnetic induction core closer to the plasma and is clamped and positioned by the screw fixing structure.

6. A method for fabricating an electromagnetic diagnostic probe for a fusion reactor environment as described in any one of claims 1 to 5, characterized in that, Includes the following steps: Interlayer vias are formed on the LTCC green ceramic tape and filled with conductor paste; racetrack-shaped conductor coils are printed on the induction layer green ceramic tape using thick film printing technology, and electrode heat dissipation patterns are printed on the first and last green ceramic tapes; the printed green ceramic tapes are aligned and stacked in the order of the first electrode and heat dissipation layer, 30 induction layers, and the last electrode and heat dissipation layer; after being compacted by isostatic pressing with warm water, they are cut into single semi-finished products; glue is removed and co-fired at 830℃ to 870℃ to form the LTCC magnetic induction core; nickel-gold is electroless plated on the surface of the exposed electrodes and heat dissipation shielding patterns; after nickel-gold plating, electrical performance screening and non-destructive testing are performed; the LTCC magnetic induction core, foamed copper buffer heat conduction layer, and alumina ceramic protection plate are installed in a 316L stainless steel probe box and fixed, and quality consistency inspection is performed.

7. The manufacturing method according to claim 6, characterized in that, The isostatic pressure of warm water is 180 kg / cm². 2 Up to 230kg / cm 2 The peak temperature of co-firing is 830℃ to 870℃, and a debinding stage is set during the heating process to remove organic matter from the green ceramic belt.

8. The manufacturing method according to claim 6, characterized in that, Non-destructive testing uses X-ray or CT scans to confirm the alignment accuracy between layers, the continuity of the racetrack conductor coil, the filling status of the interlayer vias, and whether there are delamination or crack defects after co-firing.

9. The manufacturing method according to claim 6, characterized in that, The qualification criteria for electrical performance screening are a DC resistance of not more than 120Ω and an insulation resistance of more than 1GΩ at 200V.

10. The manufacturing method according to claim 9, characterized in that, The quality consistency inspection items include dimensions, DC resistance, insulation resistance, withstand voltage, thermal cycling, leakage rate after vacuum baking, solder joint strength, and consistency of calibration coefficients.

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