Manufacturing method for superconducting coaxial cable for quantum computer

Abstract

A manufacturing method for a superconducting coaxial cable for a quantum computer, comprising the following steps: using a vacuum consumable arc melting technique to smelt a NbTi alloy; preheating a vacuum die-casting mold and applying a coating by spraying; closing the vacuum die-casting mold and performing vacuumizing, pouring a NbTi melt and performing injection, and after cooling, opening the mold to eject a NbTi capillary tube; using a spraying technique to coat the surface of a NbTi filament with PTFE particles, and after spraying is completed, performing heating curing; and using a tube threading method to thread the NbTi filament having a PTFE insulating layer into the NbTi capillary tube, and welding joints at two ends, thereby obtaining a superconducting coaxial cable. By combining vacuum die-casting, spraying, and heating curing techniques, the superconducting coaxial cable having low signal attenuation and suitable for quantum computers is manufactured.

Description

A method for preparing superconducting coaxial cable for quantum computers Technical Field

[0001] The present invention relates to the technical field of superconducting composite cable processing, and in particular to a method for preparing a superconducting coaxial cable for a quantum computer. Background Art

[0002] Quantum computers are a new type of next-generation computer under development, with a new computing model based on quantum mechanics. Coaxial cables are the bridge between quantum chips at low temperatures and measurement and control systems at room temperature. To ensure that the fragile quantum state of quantum bits is not destroyed, the cables need to have extremely low thermal conductivity, extremely low signal attenuation, and suitable characteristic impedance. The zero resistance and low thermal conductivity of NbTi superconducting materials at low temperatures make them an ideal material for preparing coaxial cables.

[0003] At present, the mainstream preparation technology of superconducting coaxial cables has been in a state of monopoly by foreign countries, which has greatly restricted the development of domestic quantum computers. Among the existing domestic superconducting coaxial cable preparation technologies, the patent publication number CN113724936A "A Low-temperature superconducting coaxial cable and processing technology" inserts the central conductor into the outer conductor tube and keeps the central conductor and outer conductor tube coaxially arranged; pours resin material into the space between the central conductor and the outer conductor tube, and compacts the resin; heats the semi-finished coaxial cable body obtained after processing to make the resin material foam to form a dielectric layer; then evacuates the semi-finished product and fills it with inert gas to form an inert gas layer to obtain a superconducting coaxial cable.

[0004] The above-mentioned prior art has a relatively complicated preparation process and only utilizes the existing center conductor and outer conductor to prepare the superconducting coaxial cable, without conducting research on the preparation of the center conductor and the outer conductor. The signal attenuation of the superconducting coaxial cable is directly related to the existing center conductor and the outer conductor, but has little correlation with the processing technology, that is, there is a lack of a complete process for preparing a superconducting coaxial cable with low signal attenuation. Summary of the Invention

[0005] The present invention provides a method for preparing a superconducting coaxial cable for a quantum computer, so as to solve the problem in the prior art that there is no relatively reliable and complete process for preparing a superconducting coaxial cable with low signal attenuation.

[0006] In one aspect, the present invention provides a method for preparing a superconducting coaxial cable for a quantum computer, comprising the following steps:

[0007] Step 1: Using vacuum consumable arc melting technology to melt the NbTi alloy to obtain a NbTi melt.

[0008] Step 2: preheat the vacuum die-casting mold and spray paint.

[0009] Step three, closing the vacuum die-casting mold and extracting the vacuum, pouring the NbTi melt and performing injection molding, and opening the mold after cooling to eject the NbTi capillary.

[0010] Step 4: spraying PTFE particles onto the surface of the NbTi filament using a spraying technique, and then heating and curing the filament after spraying to obtain a NbTi filament with a PTFE insulation layer.

[0011] Step 5: insert the NbTi filament with PTFE insulation layer into the NbTi capillary tube by using a tube insertion method, and weld joints at both ends to obtain a superconducting coaxial cable.

[0012] In one possible implementation, in step 1, the voltage of melting the NbTi alloy using vacuum consumable arc melting technology is 30-50 V, the vacuum degree is 0.001-0.01 Pa, the mass percentage of Ti in the NbTi alloy is 35%-55%, and the melting times are not less than 2 times.

[0013] In a possible implementation, in step 2, the coating is a lubricant including boron nitride and graphite.

[0014] In a possible implementation, in step 2, the mass percentage of boron nitride in the coating is 7%-15%.

[0015] The temperature for preheating the vacuum die-casting mold is 800-1200°C.

[0016] In a possible implementation, in step three, the vacuum die-casting mold is closed and vacuum is extracted to a degree of 4000-6000 Pa, and the NbTi melt is poured and injected at an injection rate of 20-60 m / s.

[0017] In a possible implementation, in step three, after cooling and ejecting the NbTi capillary tube by opening the mold, the NbTi capillary tube is trimmed by using a plasma cutting technology.

[0018] In a possible implementation, in step 4, the particle size of the PTFE particles is 20-50 μm, and the temperature for heating and curing after spraying is 350-450° C.

[0019] In a possible implementation, in step 4, before spraying the PTFE particles onto the surface of the NbTi filament using a spraying technique, the surface of the NbTi filament is ultrasonically cleaned using an organic solvent.

[0020] In a possible implementation, the organic solvent is acetone, and the ultrasonic cleaning time is 10-30 minutes.

[0021] In a possible implementation, in step five, the difference between the outer diameter of the NbTi filament with the PTFE insulation layer and the inner diameter of the NbTi capillary is 0.002-0.005 mm.

[0022] The method for preparing a superconducting coaxial cable for a quantum computer in the present invention has the following advantages:

[0023] By combining vacuum die-casting, spraying and heating curing technologies, a superconducting coaxial cable with low signal attenuation suitable for quantum computers was produced.

[0024] By adopting vacuum consumable arc melting technology to melt the NbTi alloy, the uniformity of the composition and performance of the NbTi alloy is improved, and impurities are removed at the same time.

[0025] By preheating the vacuum die-casting mold and spraying lubricant coating, the NbTi capillary is easily separated from the mold, and it is convenient to subsequently insert the NbTi filament with PTFE insulation layer into the NbTi capillary.

[0026] The PTFE particles are sprayed on the surface of the NbTi filament by using a spraying technology, and then heated and cured after the spraying is completed, thereby improving the adhesion degree of the insulation layer of the NbTi filament with the PTFE insulation layer.

[0027] By using an organic solvent to ultrasonically clean the surface of the NbTi filament, the purity of the NbTi filament is improved, thereby improving the purity of the finally prepared superconducting coaxial cable and reducing signal attenuation. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0029] FIG1 is a schematic flow chart of a method for preparing a superconducting coaxial cable for a quantum computer provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0031] As shown in FIG1 , an embodiment of the present invention provides a method for preparing a superconducting coaxial cable for a quantum computer, comprising the following steps:

[0032] Step 1: Using vacuum consumable arc melting technology to melt the NbTi alloy to obtain a NbTi melt.

[0033] Step 2: preheat the vacuum die-casting mold and spray paint.

[0034] Step three, closing the vacuum die-casting mold and extracting the vacuum, pouring the NbTi melt and performing injection molding, and opening the mold after cooling to eject the NbTi capillary.

[0035] Step 4: spraying PTFE particles onto the surface of the NbTi filament using a spraying technique, and then heating and curing the filament after spraying to obtain a NbTi filament with a PTFE insulation layer.

[0036] Step 5: insert the NbTi filament with PTFE insulation layer into the NbTi capillary tube by using a tube insertion method, and weld joints at both ends to obtain a superconducting coaxial cable.

[0037] Illustratively, in step one, the voltage for melting the NbTi alloy using vacuum consumable arc melting technology is 30-50 V, the vacuum degree is 0.001-0.01 Pa, the mass percentage of Ti in the NbTi alloy is 35%-55%, and the melting times are no less than 2 times.

[0038] Illustratively, in step 2, the coating is a lubricant including boron nitride and graphite.

[0039] Illustratively, in step 2, the mass percentage of boron nitride in the coating is 7%-15%.

[0040] The temperature for preheating the vacuum die-casting mold is 800-1200°C.

[0041] For example, in step three, the vacuum die-casting mold is closed and the vacuum degree is 4000-6000 Pa, and the NbTi melt is poured and injected at an injection rate of 20-60 m / s.

[0042] For example, in step three, after cooling and ejecting the NbTi capillary by opening the mold, the NbTi capillary is trimmed by using plasma cutting technology.

[0043] For example, in step 4, the particle size of the PTFE particles is 20-50 μm, and the temperature for heating and curing after spraying is 350-450° C.

[0044] For example, in step 4, before spraying the PTFE particles onto the surface of the NbTi filament using a spraying technique, the surface of the NbTi filament is ultrasonically cleaned using an organic solvent.

[0045] Exemplarily, the organic solvent is acetone, and the ultrasonic cleaning time is 10-30 minutes.

[0046] Illustratively, in step five, the difference between the outer diameter of the NbTi filament with the PTFE insulation layer and the inner diameter of the NbTi capillary is 0.002-0.005 mm. Example 1

[0047] Specifically, in this embodiment, in step one, the voltage for melting the NbTi alloy using vacuum consumable arc melting technology is 30 V, the vacuum degree is 0.001 Pa, the mass percentage of Ti in the NbTi alloy is 35%, and the number of melting times is 2; in step two, the temperature for preheating the vacuum die-casting mold is 800° C., and the mass percentage of boron nitride in the coating is 7%; in step three, the vacuum degree for closing the vacuum die-casting mold and extracting the vacuum is 4000 Pa, and the injection rate for pouring the NbTi melt and performing injection is 20 m / s; in step four, the surface of the NbTi filament is ultrasonically cleaned with acetone for 10 min, the particle size of the sprayed PTFE particles is 20 μm, and the temperature for heating and curing after spraying is 350° C.; in step five, the difference between the outer diameter of the NbTi filament with the PTFE insulation layer and the inner diameter of the NbTi capillary is 0.002 mm.

[0048] The signal attenuation of the superconducting coaxial cable prepared in Example 1 is lower than 0.5 dB / m at a temperature of 4-20 K. Example 2

[0049] Specifically, in this embodiment, in step one, the voltage for melting the NbTi alloy using vacuum consumable arc melting technology is 35 V, the vacuum degree is 0.004 Pa, the mass percentage of Ti in the NbTi alloy is 40%, and the number of melting times is 2; in step two, the temperature for preheating the vacuum die-casting mold is 900°C, and the mass percentage of boron nitride in the coating is 8%; in step three, the vacuum degree for closing the vacuum die-casting mold and evacuating the vacuum is 4600 Pa, and the injection rate for pouring the NbTi melt and performing injection is 30 m / s; in step four, the surface of the NbTi filament is ultrasonically cleaned with acetone for 15 min, the particle size of the sprayed PTFE particles is 30 μm, and the temperature for heating and curing after spraying is 400°C; in step five, the difference between the outer diameter of the NbTi filament with the PTFE insulation layer and the inner diameter of the NbTi capillary is 0.003 mm.

[0050] The signal attenuation of the superconducting coaxial cable prepared in Example 2 is lower than 0.4 dB / m at a temperature of 4-20 K. Example 3

[0051] Specifically, in this embodiment, in step one, the voltage for melting the NbTi alloy using vacuum consumable arc melting technology is 40 V, the vacuum degree is 0.008 Pa, the mass percentage of Ti in the NbTi alloy is 45%, and the number of melting times is 3 times; in step two, the temperature for preheating the vacuum die-casting mold is 1000° C., and the mass percentage of boron nitride in the coating is 9.5%; in step three, the vacuum degree for closing the vacuum die-casting mold and extracting the vacuum is 5100 Pa, and the injection rate for pouring the NbTi melt and performing injection is 34 m / s; in step four, the surface of the NbTi filament is ultrasonically cleaned with acetone for 20 min, the particle size of the sprayed PTFE particles is 35 μm, and the temperature for heating and curing after spraying is 420° C.; in step five, the difference between the outer diameter of the NbTi filament with the PTFE insulation layer and the inner diameter of the NbTi capillary is 0.004 mm.

[0052] The signal attenuation of the superconducting coaxial cable prepared in Example 3 is lower than 0.6 dB / m at a temperature of 4-20 K. Example 4

[0053] Specifically, in this embodiment, in step one, the voltage for melting the NbTi alloy using vacuum consumable arc melting technology is 50 V, the vacuum degree is 0.01 Pa, the mass percentage of Ti in the NbTi alloy is 55%, and the number of melting times is 3 times; in step two, the temperature for preheating the vacuum die-casting mold is 1200° C., and the mass percentage of boron nitride in the coating is 15%; in step three, the vacuum degree for closing the vacuum die-casting mold and extracting the vacuum is 6000 Pa, and the injection rate for pouring the NbTi melt and performing injection is 60 m / s; in step four, the surface of the NbTi filament is ultrasonically cleaned with acetone for 30 min, the particle size of the sprayed PTFE particles is 50 μm, and the temperature for heating and curing after spraying is 450° C.; in step five, the difference between the outer diameter of the NbTi filament with the PTFE insulation layer and the inner diameter of the NbTi capillary is 0.005 mm.

[0054] The signal attenuation of the superconducting coaxial cable prepared in Example 4 is lower than 0.7 dB / m at a temperature of 4-20 K.

[0055] The embodiment of the present invention combines vacuum die-casting, spraying and heating curing technologies to prepare a superconducting coaxial cable with low signal attenuation and suitable for quantum computers.

[0056] By adopting vacuum consumable arc melting technology to melt the NbTi alloy, the uniformity of the composition and performance of the NbTi alloy is improved, and impurities are removed at the same time.

[0057] By preheating the vacuum die-casting mold and spraying lubricant coating, the NbTi capillary is easily separated from the mold, and it is convenient to subsequently insert the NbTi filament with PTFE insulation layer into the NbTi capillary.

[0058] The PTFE particles are sprayed on the surface of the NbTi filament by using a spraying technology, and then heated and cured after the spraying is completed, thereby improving the adhesion degree of the insulation layer of the NbTi filament with the PTFE insulation layer.

[0059] By using an organic solvent to ultrasonically clean the surface of the NbTi filament, the purity of the NbTi filament is improved, thereby improving the purity of the finally prepared superconducting coaxial cable and reducing signal attenuation.

[0060] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0061] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A method for preparing a superconducting coaxial cable for a quantum computer, characterized in that: The following steps are involved: Step 1: Smelting the NbTi alloy using a vacuum consumable arc melting technique to obtain a NbTi melt; Step 2: preheating the vacuum die-casting mold and spraying the coating; Step 3, closing the vacuum die-casting mold and extracting the vacuum, pouring the NbTi melt and performing injection molding, and after cooling, opening the mold and ejecting the NbTi capillary; Step 4: spraying PTFE particles onto the surface of the NbTi filament using a spraying technique, and then heating and curing the filament to obtain a NbTi filament with a PTFE insulation layer; Step 5: insert the NbTi filament with PTFE insulation layer into the NbTi capillary tube by using a tube insertion method, and weld joints at both ends to obtain a superconducting coaxial cable.

2. The method for preparing a superconducting coaxial cable for a quantum computer according to claim 1, characterized in that: In step 1, the voltage of melting the NbTi alloy using vacuum consumable arc melting technology is 30-50V, the vacuum degree is 0.001-0.01Pa, the mass percentage of Ti in the NbTi alloy is 35%-55%, and the melting times are not less than 2 times.

3. The method for preparing a superconducting coaxial cable for a quantum computer according to claim 1, characterized in that: In step 2, the coating is a lubricant including boron nitride and graphite.

4. The method for preparing a superconducting coaxial cable for a quantum computer according to claim 3, characterized in that: In step 2, the mass percentage of boron nitride in the coating is 7%-15%; The temperature for preheating the vacuum die-casting mold is 800-1200°C.

5. The method for preparing a superconducting coaxial cable for a quantum computer according to claim 1, characterized in that: In step three, the vacuum die-casting mold is closed and the vacuum degree is 4000-6000 Pa, and the NbTi melt is poured and injected at an injection rate of 20-60 m / s.

6. The method for preparing a superconducting coaxial cable for a quantum computer according to claim 1, characterized in that: In step three, after cooling and ejecting the NbTi capillary tube by opening the mold, the NbTi capillary tube is trimmed by using plasma cutting technology.

7. The method for preparing a superconducting coaxial cable for a quantum computer according to claim 1, characterized in that: In step 4, the particle size of the PTFE particles is 20-50 μm, and the temperature for heating and curing after spraying is 350-450° C.

8. The method for preparing a superconducting coaxial cable for a quantum computer according to claim 1, characterized in that: In step 4, before spraying the PTFE particles onto the surface of the NbTi filament using a spraying technique, the surface of the NbTi filament is ultrasonically cleaned using an organic solvent.

9. The method for preparing a superconducting coaxial cable for a quantum computer according to claim 8, characterized in that: The organic solvent is acetone, and the ultrasonic cleaning time is 10-30 minutes.

10. The method for preparing a superconducting coaxial cable for a quantum computer according to claim 1, characterized in that: In step 5, the difference between the outer diameter of the NbTi filament with the PTFE insulation layer and the inner diameter of the NbTi capillary is 0.002-0.005 mm.

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