Temperature sensing probe and refrigerator cold plate temperature sensing equipment

Abstract

The utility model provides a temperature sensing probe and a refrigerator cold plate temperature sensing device, comprising an optical fiber probe, a probe fixing member and a microwave antenna, the temperature sensing probe is mainly suitable for application scenarios needing to measure sample shell temperature, such as refrigerator cold plate, chip surface temperature and the like; through the structural design of the optical fiber probe and the probe fixing piece, the diamond block containing the NV color center can be in sufficient and stable contact with the sample to be detected, and it is guaranteed that the temperature detection process is effectively implemented. Meanwhile, the utility model provides temperature sensing equipment suitable for monitoring the temperature of the cold plate of the dilution refrigerator, and the application feasibility of the NV color center sensing technology in the field is verified.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of refrigeration machine temperature detection, especially to a temperature sensing probe and cold plate temperature sensing equipment for dilution refrigerator. BACKGROUND

[0002] The ultra-low temperature dilution refrigerator is an indispensable core basic equipment in the forefront fields of modern condensed matter physics, quantum information science, low temperature electronics and deep space exploration. It can continuously generate and maintain an ultra-low temperature environment of millikelvin (mK) or even microkelvin (μK) through the phase transition dilution effect of helium-3 / helium-4 mixed liquid at extremely low temperature. In the system, the cold plates (such as 50K, 4K, 0.1K cold plates) at different temperature stages constitute the key thermodynamic framework, which not only bears the heavy responsibility of intercepting and dissipating heat radiation from the room temperature environment, but also is the direct installation platform of experimental samples (such as superconducting quantum bit chips, low-dimensional materials, high-sensitivity detectors). Therefore, accurate, real-time and in-situ monitoring of the temperature of these cold plates is an absolute prerequisite for ensuring the efficient and stable operation of the refrigerator, evaluating the system thermal load, and ensuring the reliability of experimental data.

[0003] As an excellent quantum sensing material in recent years, diamond NV color center not only has outstanding performance in magnetic field measurement, but also has extremely high accuracy for temperature sensing. It converts the accurate change amount of the nitrogen-vacancy color center ground state energy level zero field splitting (D) into temperature information through optical detection magnetic resonance technology. At the experimental level, this technology has achieved temperature resolution of sub-millikelvin or even microkelvin in the millikelvin temperature range, which is significantly better than traditional electrical sensors such as silicon diodes. Therefore, it is necessary to design an NV color center temperature sensing probe suitable for dilution refrigerator cold plate measurement. SUMMARY

[0004] To achieve the above object and other related objects, the first aspect of the utility model provides a temperature sensing probe, comprising:

[0005] The optical fiber probe comprises a first optical fiber and a diamond block containing a system of NV color centers. The bottom end of the first optical fiber is provided with a rigid ferrule, and the diamond block is attached to the bottom surface of the rigid ferrule. The bottom surface of the diamond block is used to abut against the sample to be measured. Excitation light is loaded from the upper part of the first optical fiber and irradiates the diamond block at the bottom;

[0006] The probe fixing member comprises a first component and a second component connected thereto, the first component is used to connect with the sample to be measured, and the second component is used to connect the rigid ferrule. The second component can drive the rigid ferrule and the diamond block at the bottom of the rigid ferrule to move up and down by controlling the lifting of the second component.

[0007] The microwave antenna is used to radiate a microwave field to the diamond block.

[0008] The temperature sensing probe as claimed in the preceding description, further, the diamond block is a cuboid, and a bottom surface of the diamond block is perpendicular to a trajectory extension line of the rigid plug moving up and down.

[0009] The temperature sensing probe as claimed in the preceding description, further, the microwave antenna comprises a ring-shaped radiation part and a strip-shaped feeding part, and the two parts are connected vertically to form an L-shaped structure, and when the temperature sensing probe is connected with the optical fiber probe, the lower part of the rigid plug is inserted into a hole of the ring-shaped radiation part, and the diamond block is located at a bottom side of the ring-shaped radiation part.

[0010] The temperature sensing probe as claimed in the preceding description, further, the ring-shaped radiation part comprises a ring-shaped substrate and a copper-plated radiation circuit arranged on a bottom surface of the ring-shaped substrate.

[0011] The temperature sensing probe as claimed in the preceding description, further, the second assembly comprises a bolt lifting assembly and a plug connecting plate, the bolt lifting assembly is used to control the plug connecting plate to move up and down, and a top surface of the plug connecting plate comprises a plug-in through hole, one side of the plug-in through hole is provided with a plug-in hole, the rigid plug can enter the plug-in through hole from the plug-in hole, and a plug-in structure is arranged between the upper part of the rigid plug and the plug-in through hole.

[0012] To achieve the above object and other related objects, the second aspect of the utility model provides a refrigeration machine cold plate temperature sensing equipment for temperature measurement of a dilution refrigeration machine cold plate, comprising:

[0013] The temperature sensing probe as claimed in the preceding description;

[0014] The double-color sheet is used for penetrating excitation light and reflecting fluorescent light generated by NV color centers.

[0015] The laser module is used for outputting excitation light, and the excitation light enters the temperature sensing probe after penetrating the double-color sheet.

[0016] The microwave module is used for outputting a microwave signal to the temperature sensing probe.

[0017] The fluorescent light acquisition module is used for acquiring fluorescent light generated by NV color centers reflected by the double-color sheet and generating a fluorescent light electrical signal.

[0018] The host computer is used at least for human-computer interaction, fluorescent light electrical signal processing and microwave-laser control.

[0019] The refrigeration machine cold plate temperature sensing equipment as claimed in the preceding description, further, the laser module comprises an adjustable attenuation sheet, which is used for adjusting the power of excitation light.

[0020] The refrigeration machine cold plate temperature sensing equipment as claimed in the preceding description, further, the laser module comprises an acousto-optic modulator, which is used for controlling output of pulsed excitation light.

[0021] The temperature sensing probe and the refrigeration machine cold plate temperature sensing device have the beneficial effects that: the structure design of the optical fiber probe and the probe fixing piece can realize sufficient and stable contact of the diamond block containing NV color centers and the sample to be measured, and ensure effective implementation of the temperature detection process.

[0022] The temperature sensing probe and the refrigeration machine cold plate temperature sensing device have the beneficial effects that: the structure design of the optical fiber probe and the probe fixing piece can realize sufficient and stable contact of the diamond block containing NV color centers and the sample to be measured, and ensure effective implementation of the temperature detection process. Meanwhile, a temperature sensing device suitable for dilution refrigerator cold plate temperature monitoring is provided, and the feasibility of application of NV color center sensing technology in the field is verified. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 The structure front view of the temperature sensing probe installed on the sample;

[0024] Figure 2 The three-dimensional schematic view of the optical fiber probe;

[0025] Figure 3 The three-dimensional schematic view of the probe fixing piece;

[0026] Figure 4 The three-dimensional schematic view of the microwave antenna;

[0027] Figure 5 The sectional view of the microwave antenna and the optical fiber probe assembly;

[0028] Figure 6 The exploded view of each component in the temperature sensing probe;

[0029] Figure 7 The system block diagram of the cold plate temperature sensing device.

[0030] REFERENCE SIGNS:

[0031] Temperature sensing probe; 2 - double color sheet; 3 - laser module; 4 - microwave module; 5 - fluorescence acquisition module; 6 - host computer; 7 - sample to be measured; 10 - optical fiber probe; 20 - probe fixing piece; 30 - microwave antenna; 101 - first optical fiber; 102 - diamond block; 103 - rigid ferrule; 104 - metal plug; 105 - plug sleeve; 201 - first component; 202 - second component; 2021 - ferrule connecting plate; 2022 - plug through hole; 2023 - ferrule inlet and outlet; 2024 - plug slot; 301 - annular radiation part; 302 - strip-shaped feed part; 3011 - copper-plated radiation line; 31 - 532nm laser source; 32 - adjustable attenuation sheet; 33 - acousto-optic modulator; 41 - microwave source; 42 - microwave amplifier; 43 - microwave circulator; 51 - photodetector; 52 - filter sheet. Detailed Implementation

[0032] The following specific embodiments illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification.

[0033] It should be understood that the structures, proportions, sizes, etc., illustrated in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and to facilitate understanding. They are not intended to limit the scope of this invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, provided they do not affect the effectiveness or purpose of this invention, should still fall within the scope of the technical content disclosed herein. Furthermore, the terms "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and not intended to limit the scope of this invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of this invention.

[0034] Example 1

[0035] like Figure 1 As shown, this example presents a temperature sensing probe, comprising an optical fiber probe 10, a probe holder 20, and a microwave antenna 30. This temperature sensing probe is mainly suitable for applications requiring the measurement of sample surface temperature, such as the cold plate of a refrigerator or the surface temperature of a chip.

[0036] Among them, as attached Figure 2As shown, the optical fiber probe 10 comprises a first optical fiber 101 and a diamond block 102 containing a system of NV color centers, the bottom end of the first optical fiber 101 is provided with a rigid ferrule 103, the diamond block 102 is attached to the bottom surface of the rigid ferrule 103, the bottom surface of the diamond block 102 is used to abut the sample 7 to be measured, and the excitation light is loaded from the upper part of the first optical fiber 101 and irradiates the diamond block 102 at the bottom; for the rigid ferrule 103, which is generally made of ceramic material, the cladding part of the first optical fiber 101 is wrapped inside, the rigid ferrule is generally used for connection with optical fiber couplers and other devices, and the side away from the diamond block 102 is generally provided with a metal plug 104; in this example, since it is necessary to move the rigid ferrule 103 up and down to achieve sufficient contact of the diamond block 102 with the surface of the sample 7 to be measured, for this purpose, in one preferred example, the diamond block 102 is selected as a cuboid (preferably, the size is 200um*200um*100um), when connected with the first optical fiber 101, the bottom surface of the diamond block 102 is perpendicular to the extension line of the track of the rigid ferrule 103 moving up and down, and then the optical fiber probe 10 is installed through the probe fixing member 20, so that the rigid ferrule 103 is perpendicular to the surface of the sample 7 to be measured; at this time, by controlling the lifting movement of the rigid ferrule 103, sufficient contact of the bottom surface of the diamond block 102 with the sample 7 to be measured can be achieved, the foregoing design ensures the parallelism of the bottom surface of the diamond block 102 with the surface of the sample 7 to be measured, effectively guarantees the contact area, and is beneficial to temperature transmission and sensing; in this example, the first optical fiber 101 is preferably a multimode optical fiber.

[0037] In the production of the optical fiber probe 10, the diamond block 102 can be placed on a horizontal plane, optical glue is applied at the bottom of the rigid ferrule 103, and then the vertically placed rigid ferrule 103 is controlled to move down from above to bond the upper surface of the diamond block 102, until the optical glue is cured, and then the diamond block 102 is removed from the horizontal plane; this bonding method can ensure the perpendicularity of the bottom surface of the diamond block 102 with the center line of the steel core ferrule, and thus facilitate subsequent control of sufficient contact of the bottom surface of the diamond block with the sample to be measured.

[0038] The probe fixing member 20 comprises a first component 201 and a liftable second component 202 fixedly connected thereto, the first component 201 is used to connect with the sample 7 to be measured, and the second component 202 is used to connect the rigid ferrule 103, wherein the second component 202 is controlled to lift to drive the rigid ferrule 103 and the diamond block 102 at the bottom of the rigid ferrule 103 to move up and down; an example structure is shown in the accompanying drawings Figure 3As shown, the first component 201 is a thin plate structure, which is fixed to the sample 7 to be tested by adhesion, screwing or the like, and includes a bolt lifting component and a ferrule connecting plate 2021. The bolt lifting component is used to control the up-down movement of the ferrule connecting plate 2021. The top surface of the ferrule connecting plate 2021 includes a plug-in through hole 2022, one side of which is provided with a ferrule inlet and outlet 2023. The rigid ferrule 103 can enter the plug-in through hole 2022 from the ferrule inlet and outlet 2023. The plug-in structure is provided between the upper part of the rigid ferrule 103 and the plug-in through hole 2022. Regarding the plug-in mechanism, one half is a metal plug-in part 104 on the rigid ferrule 103, and the other half is a plug-in clamping groove 2024 provided in the plug-in through hole 2022. The plug-in clamping groove 2024 and the metal plug-in part 104 can be adaptively connected. After the optical fiber probe 10 is connected through the probe fixing part 20, the bottom surface of the diamond block 102 should be parallel to the sample 7 to be tested as much as possible. Therefore, in the example scheme, the thin plate structure, the ferrule connecting plate 2021 and the surface of the sample 7 to be tested should be kept parallel. After the plug-in clamping groove 2024 and the metal plug-in part 104 are connected, the rigid ferrule 103 should be perpendicular to the ferrule connecting plate 2021.

[0039] Among them, the microwave antenna 30 is used to radiate a microwave field to the diamond block 102. In the example scheme, as shown in the accompanying drawings, Figure 4 As shown, the microwave antenna 30 includes a ring-shaped radiation part 301 and a strip-shaped feeding part 302, which are vertically connected to form an L-shaped structure. When the optical fiber probe 10 is connected, the lower part of the rigid ferrule 103 is plugged into the inner hole of the ring-shaped radiation part 301, and the diamond block 102 is located at the bottom side of the ring-shaped radiation part 301. Regarding the fixing method of the rigid ferrule 103 and the ring-shaped radiation part 301, preferably, as shown in the accompanying drawings, Figure 5 As shown, the plug-in sleeve 105 is further provided at the lower part of the tube wall of the rigid ferrule 103. The upper part has a diameter larger than the lower part. The lower part can be concentrically plugged into the inner hole of the ring-shaped radiation part 301 with extrusion force. Further, the ring-shaped radiation part 301 includes a ring-shaped substrate and a copper-plated radiation circuit 3011 provided on the bottom surface of the ring-shaped substrate. The copper-plated radiation circuit 3011 is designed on the bottom surface, which is closer to the diamond block 102, so that efficient microwave field radiation can be achieved.

[0040] Regarding the mounting method of the above optical fiber probe, probe fixing part and microwave antenna, in the example scheme, as shown in the accompanying drawings, Figure 6As shown, the probe holder 20 can be fixed to the surface of the sample to be tested beforehand, either by adhesive or by screws. If the sample to be tested is a cold plate of a refrigerator, screw holes for matching the probe holder 20 should be designed on the cold plate beforehand. Assemble the microwave antenna 30 and the fiber optic probe 10 so that the rigid ferrule 103 is inserted into the inner hole of the annular radiating part 301. Pay attention to controlling the distance of the diamond block 102 penetrating the bottom surface of the annular radiating part 301 so that the microwave field of the annular radiating part 301 can efficiently radiate the diamond block 102. Then move the fiber optic probe 10 so that its rigid ferrule 103 passes through the ferrule inlet and outlet 2023 and enters the insertion slot 2024, and press down so that the insertion slot 2024 is engaged with the metal connector 104. Finally, control the rigid ferrule 103 to move down by the bolt lifting assembly and observe whether the diamond block 102 is in contact with the surface of the sample to be tested. When the two are in close contact, the probe installation is complete.

[0041] Example 2

[0042] As attached Figure 7 As shown, this embodiment provides a temperature sensing device for a cold plate of a refrigeration machine, used for temperature measurement of the cold plate of a dilution refrigeration machine, including a temperature sensing probe 1, a dual-color filter 2, a laser module 3, a microwave module 4, a fluorescence acquisition module 5, and a host 6.

[0043] In this example, the temperature sensing probe 1 is the same as the temperature sensing probe introduced in Example 1. It is installed on the sample to be tested 7 inside the dilution refrigerator. The sample to be tested 7 is the cold plate. The surface temperature of the cold plate is sensed by the diamond block 102. When the temperature changes, the center frequency of the fluorescence characterization data-microwave frequency curve obtained by optical detection magnetic resonance technology will shift. This shift is linearly related to the temperature change. The temperature value of the cold plate can be obtained by calculating this shift.

[0044] In this example, the dual-color filter 2 is used to transmit the excitation light and reflect the fluorescence generated by the NV color center. Since the excitation light and fluorescence are both input and output through the same optical fiber, the dual-color filter 2 needs to be added in the optical path. It can ensure the transmission of the excitation light and also separate the fluorescence signal and import it into the fluorescence acquisition module 5. Typically, the dual-color filter 2 is set in a cage structure and the fiber-cage structure-fiber connection is realized through an optical fiber coupler. In this scheme, the dual-color filter 2 is set on the outside of the refrigerator. Except for the temperature sensing probe 1, all other modules are on the outside of the refrigerator. The two are connected by optical fiber and radio frequency transmission line, and the connection between the optical fiber and radio frequency transmission line and the refrigerator has been sealed and heat-insulated.

[0045] In the example, the laser module 3 is used to output excitation light, and the excitation light enters the temperature sensing probe 1 after penetrating the dichroic film 2; for example, for NV color centers, a 532nm laser is generally used as excitation light, so the laser module should include a 532nm laser source 31, and the output excitation light can penetrate the dichroic film through a fiber-optic connection or directly in the form of spatial light.

[0046] In the example, the microwave module 4 is used to output microwave signals to the temperature sensing probe 1, and the microwave signals enter the microwave antenna 30 and finally form a microwave field of the radiating diamond block 102; for example, the microwave signals are sweep signals with a frequency of about 2.8GHz-2.9GHz; for example, the microwave module 4 includes a microwave source 41, a microwave amplifier 42, and a microwave circulator 43, and the initial microwave signals output by the microwave source 41 are first amplified by the microwave amplifier 42 and then output after passing through the microwave circulator 43.

[0047] The fluorescence collection module 5 is used to collect the fluorescence generated by the NV color centers reflected by the dichroic film 2 and generate a fluorescence electrical signal; for example, it includes a photodetector 51 and a filter 52 arranged at the input port of the photodetector 51, and the filter is used to filter out stray signals, and the photodetector 51 is preferably an avalanche diode.

[0048] The host computer 6 is used for at least human-computer interaction, fluorescence electrical signal processing, and microwave-laser control.

[0049] Because there is a very high requirement for temperature control in the dilution refrigerator, considering that the excitation light used in the scheme may cause the cold plate to warm up, in order to suppress this effect, in a preferred solution, the laser module includes an adjustable attenuator 32 for adjusting the power of the excitation light, which can be as low as 100μW or less; by reducing the power of the excitation light, the warming effect of the excitation light on the cold plate is greatly weakened.

[0050] In another solution, an acousto-optic modulator 33 can also be involved in the laser module for controlling the output of pulsed excitation light; in the example, pulsed light is used for temperature detection to reduce the total energy input of the excitation light. Of course, both solutions can exist at the same time to double the suppression of the warming effect of the excitation light on the cold plate.

[0051] The above embodiments only exemplarily illustrate the principles and effects of the present application, and are not used to limit the present application. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical thought disclosed by the present application should be covered by the claims of the present application.

Claims

1. A temperature sensing probe, characterized by, The temperature sensing probe comprises a fiber probe and a microwave antenna. The fiber probe comprises a first optical fiber and a diamond block containing a system of NV color centers. The bottom end of the first optical fiber is provided with a rigid ferrule. The diamond block is attached to the bottom surface of the rigid ferrule.

2. The temperature sensing probe of claim 1, wherein, The bottom surface of the diamond block is used to abut against the sample to be measured.

3. The temperature sensing probe of claim 1, wherein, The excitation light is loaded from the upper part of the first optical fiber and irradiates the diamond block at the bottom.

4. The temperature sensing probe of claim 3, wherein, The probe fixing member comprises a first component and a second component fixed thereto.

5. The temperature sensing probe of claim 3, wherein, The first component is used to connect with the sample to be measured.

6. A cryocooler cold plate temperature sensing apparatus for temperature measurement of a dilution refrigerator cold plate, characterized by, The second component is used to connect with the rigid ferrule. The second component is used to control the up-and-down movement of the rigid ferrule and the diamond block at the bottom of the rigid ferrule. The microwave antenna is used to radiate a microwave field to the diamond block. The diamond block is a cuboid. The bottom surface of the diamond block is perpendicular to the extension line of the track of the up-and-down movement of the rigid ferrule. The microwave antenna comprises a ring-shaped radiation part and a strip-shaped feeding part. When the fiber probe is connected with the microwave antenna, the lower part of the rigid ferrule is inserted into the inner hole of the ring-shaped radiation part, and the diamond block is located at the bottom side of the ring-shaped radiation part.

7. The chiller cold plate temperature sensing device of claim 6, wherein, The ring-shaped radiation part comprises a ring-shaped substrate and a copper-plated radiation circuit arranged at the bottom surface of the ring-shaped substrate.

8. The chiller cold plate temperature sensing device of claim 6, wherein, The second component comprises a bolt lifting assembly and a ferrule connecting plate.

9. The chiller cold plate temperature sensing device of claim 6, wherein, The bolt lifting assembly is used to control the up-and-down movement of the ferrule connecting plate. The top surface of the ferrule connecting plate comprises a plug-in through hole. One side of the plug-in through hole is provided with a ferrule inlet and outlet. The rigid ferrule can enter the plug-in through hole from the ferrule inlet and outlet. The upper part of the rigid ferrule is provided with a plug-in structure between the rigid ferrule and the plug-in through hole. The temperature sensing probe according to any one of claims 1-5; The dichroic sheet is used to penetrate the excitation light and reflect the fluorescence generated by the NV color centers. The laser module is used to output the excitation light. The excitation light penetrates the dichroic sheet and enters the temperature sensing probe. The microwave module is used to output the microwave signal to the temperature sensing probe. The fluorescence acquisition module is used to acquire the fluorescence generated by the NV color centers reflected by the dichroic sheet and generate a fluorescence electrical signal. The host is used for at least human-computer interaction, processing of the fluorescence electrical signal, and microwave-laser control. The laser module comprises an adjustable attenuator for adjusting the power of the excitation light. The laser module comprises an acousto-optic modulator for controlling the output of pulsed excitation light. The microwave module comprises a microwave source, a microwave amplifier, and a microwave circulator. The initial microwave signal output by the microwave source is first passed through the microwave amplifier and then passed through the microwave circulator before being output.

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