CN-122018276-A - Blackbody radiation shielding device suitable for ultrahigh vacuum environment

CN122018276ACN 122018276 ACN122018276 ACN 122018276ACN-122018276-A

Abstract

The invention discloses a blackbody radiation shielding device suitable for an ultrahigh vacuum environment, which comprises an annular cavity, wherein 1 pair of atomic beam inlets and outlets and 5 pairs of optical windows are arranged in the circumferential direction of the annular cavity, a cavity bottom plate is arranged at the bottom of the annular cavity, a cavity cover is arranged at the top of the annular cavity, the cavity cover and the cavity bottom plate are respectively provided with an optical window, a flange plate compresses a C-shaped heat conducting plate provided with a platinum resistance probe on the lower surface of the cavity bottom plate and is fixedly connected with the cavity bottom plate, and a water-cooling MOT coil compresses a semiconductor refrigerating sheet on the lower surface of the flange plate and is fixedly connected with the flange plate. The invention fixes the platinum resistor outside vacuum, can be detached at any time for secondary calibration, eliminates the influence of vacuum baking on the platinum resistor, is beneficial to improving the temperature measurement precision, reduces the temperature fluctuation in the cavity by actively controlling the temperature in the shielding cavity through the semiconductor refrigerating sheet and the C-shaped heat conducting plate, and remarkably improves the uncertainty of atomic optical clock frequency caused by blackbody radiation frequency shift.

Inventors

Xiong Zhuanxian
HUANG PAN
ZHU QIANG
WANG BING
XIONG DEZHI
HE LINGXIANG
LV BAOLONG

Assignees

中国科学院精密测量科学与技术创新研究院

Dates

Publication Date: 20260512
Application Date: 20260304
Priority Date: 20260113

Claims (10)

1. The utility model provides a blackbody radiation shielding device suitable for ultra-high vacuum environment, including annular cavity (1), a serial communication port, the circumference of annular cavity (1) is provided with 1 pair of atomic beam import and export and 5 pair of optical windows, the bottom of annular cavity (1) is provided with the cavity bottom plate, the top of annular cavity (1) is provided with chamber lid (2), be provided with optical windows on chamber lid (2) and the cavity bottom plate respectively, the central axis of atomic beam import and export, the central axis of the optical window pair of annular cavity (1) circumference setting and the central axis of the optical window pair of annular cavity (1) vertical setting all pass through the center of annular cavity (1), the central axis of wherein 1 optical window pair of annular cavity (1) circumference and the central axis mutually perpendicular of atomic beam import and export, the lower surface of cavity bottom plate is fixed and is provided with temperature control and measuring part, temperature control and measuring part below is fixed and is provided with water-cooling MOT coil (10).
2. The blackbody radiation shielding device suitable for the ultrahigh vacuum environment according to claim 1, wherein the temperature control and measurement component comprises a C-shaped heat conducting plate (3), a flange plate (4), a platinum resistance probe (8) and a semiconductor refrigerating plate (9), a No. 2 screw (1102) sequentially penetrates through the annular cavity (1) and the C-shaped heat conducting plate (3) from top to bottom, the C-shaped heat conducting plate (3) is fastened on the lower surface of a cavity bottom plate, the No. 3 screw (1103) sequentially penetrates through the flange plate (4) and the C-shaped heat conducting plate (3) from bottom to top, the flange plate (4) is pre-fastened on the lower surface of the C-shaped heat conducting plate (3), the C-shaped heat conducting plate (3) and the flange plate (4) are fixed through welding, the platinum resistance probe (8) penetrates through a through hole arranged on the flange plate (4) and then is fixed in the probe mounting hole, the semiconductor refrigerating plate (9) is fixed on the upper surface of a water-cooled MOT coil (10) through heat conducting epoxy resin, and the water-cooled MOT coil (10) is fixedly presses the upper surface of the semiconductor refrigerating plate (9) on the upper surface of the flange plate (4) and the flange plate is fixed on the lower surface of the flange plate (4).
3. The blackbody radiation shielding device suitable for the ultrahigh vacuum environment according to claim 2, wherein the number of the semiconductor refrigeration sheets (9) is multiple, two semiconductor refrigeration sheets (9) are connected in series to form a refrigeration unit, the refrigeration units are connected in parallel, and the semiconductor refrigeration sheets (9) are uniformly and symmetrically distributed along the central axis of the annular cavity (1).
4. The blackbody radiation shielding device suitable for the ultra-high vacuum environment according to claim 2, wherein the platinum resistance probe (8) comprises a platinum resistance and an oxygen-free copper screw, the platinum resistance is welded on the end face of the oxygen-free copper screw through an indium layer, and the oxygen-free copper screw is in threaded connection with the probe mounting hole.
5. The blackbody radiation shielding device suitable for the ultrahigh vacuum environment according to claim 2, wherein the probe mounting hole is a blind hole, and a heat conduction thin wall is formed between the bottom of the probe mounting hole and the upper surface of the C-shaped heat conducting plate (3).
6. A blackbody radiation shield suitable for ultra-high vacuum environment according to claim 2, wherein the atomic beam inlet and outlet are an atomic beam inlet channel (501) and an atomic beam outlet channel (502), the circumferentially arranged pair of optical windows of the annular cavity (1) are a first flat window (601) and a sixth flat window (606), a second flat window (602) and a seventh flat window (607), a third flat window (603) and an eighth flat window (608), a fourth flat window (604) and a ninth flat window (609) and a fifth flat window (605) and a tenth flat window (610), the pair of optical windows of the annular cavity (1) are an eleventh flat window (611) and a twelfth flat window (612), respectively, the first flat window (601) to the tenth flat window (610) are pressed onto the annular cavity (1) by means of a window (7), respectively, the windows (601) to the tenth flat window (610) are pressed onto the annular cavity (1101) by means of a press screw (1101) by means of a pressing ring (1) and the flat window (1101) are fixed onto the annular cavity (1101) by means of a screw (1101) by pressing the flat window (1) onto the bottom plate (1101), the twelfth flat window sheet (612) is pressed on the cavity cover (2) through the window sheet pressing ring (7), and the window sheet pressing ring (7) for pressing the twelfth flat window sheet (612) is fixed on the cavity cover (2) through a No. 1 screw (1101).
7. The blackbody radiation shielding device suitable for the ultrahigh vacuum environment according to claim 6, wherein the materials of the screw No.1 (1101), the screw No. 2 (1102) and the screw No. 3 (1103) are TC4 titanium alloy, screw through holes are formed from screw caps to screw tips of the screw No.1 (1101), the screw No. 2 (1102) and the screw No. 3 (1103), and screw holes which are connected with the screw No.1 (1101) in an adapting way on the annular cavity (1) are blind holes.
8. The blackbody radiation shielding device suitable for the ultrahigh vacuum environment according to claim 6, wherein the annular cavity (1), the cavity cover (2), the cavity bottom plate, the C-shaped heat conducting plate (3), the window sheet pressing ring (7) arranged on the cavity cover (2) and the window sheet pressing ring (7) arranged on the cavity bottom plate are positioned in the same radial direction and provided with gaps.
9. The blackbody radiation shielding device suitable for the ultrahigh vacuum environment according to claim 6, wherein the annular cavity (1), the cavity bottom plate, the cavity cover (2), the C-shaped heat conducting plate (3), the atomic beam inlet channel (501) and the atomic beam outlet channel (502) are all made of oxygen-free copper, the inner surface of the annular cavity (1), the inner surface of the cavity bottom plate, the inner surface of the cavity cover (2), the inner surface of the atomic beam inlet channel (501) and the inner surface of the atomic beam outlet channel (502), and the two side plate surfaces and the edge surface of the C-shaped heat conducting plate (3) are coated with conductive coatings with the heat radiation coefficient of 0.95, and the inner surfaces of the first flat window (601) to the twelfth flat window (612) are coated with ITO antireflection films.
10. The blackbody radiation shielding device suitable for the ultrahigh vacuum environment according to claim 9, wherein the conductive coating is formed by fully stirring and mixing multiwall carbon nanotube powder with purity more than 99.9% and organic silicon resin glue according to a mass ratio of 1:2.

Description

Blackbody radiation shielding device suitable for ultrahigh vacuum environment Technical Field The invention relates to the field of atomic light frequency standards, in particular to a blackbody radiation shielding device suitable for an ultrahigh vacuum environment. Background The optical atomic clock uses the narrow linewidth transition of atoms in the optical wave band as a frequency reference, has frequency stability and uncertainty far exceeding those of the traditional microwave clock, and is expected to become the next generation time-frequency standard. Blackbody Radiation (BBR) frequency shift is a major source of uncertainty in optical clock systems. For most optical clock systems, the contribution of the blackbody radiation frequency shift dominates the system uncertainty evaluation table, which is a major obstacle limiting the entry of optical clock uncertainty into the order of E-19. Therefore, precise control and characterization of blackbody radiation frequency shift is a key technique for achieving high-precision atomic optical clocks. The blackbody radiation frequency shift of atomic clock transition is caused by thermal radiation field around atoms and is closely related to temperature fluctuation and temperature gradient of the radiation field. In order to evaluate the effect of the thermal radiation field on the optical clock, it is necessary to precisely control the ambient temperature of the experimental apparatus under room temperature conditions to improve the blackbody radiation frequency shift of the optical clock. In order to realize accurate control and characterization of blackbody radiation frequency shift, the first idea is to assist finite element thermal radiation analysis by integrally controlling and monitoring the temperature of a vacuum cavity at multiple points. The technical scheme requires to accurately control the whole environment temperature of the system so as to reduce the whole temperature nonuniformity of the vacuum cavity, and is generally realized by adopting a precise water cooling device or a precise air conditioner, the whole structure of the device is relatively complex, and the second thinking is that a low-temperature cavity is designed in vacuum by adopting a low-temperature technology and atoms are transferred into the low-temperature cavity by adopting a mobile optical lattice technology, or atoms are directly cooled and trapped in the low-temperature cavity, so that the blackbody radiation frequency shift and the uncertainty thereof are obviously reduced. The technical scheme has the most remarkable effects, but the vacuum internal low-temperature structure is complex in design and needs to be matched with expensive low-temperature circulating equipment, so that the light clock is not beneficial to carrying and miniaturization, and the third thinking is that the scheme of the vacuum internal blackbody radiation shielding cavity is adopted, and the scheme realizes a uniform heat radiation environment by placing a high-heat-conductivity blackbody radiation shielding cavity in vacuum. Because the blackbody radiation shielding cavity is positioned in vacuum and insensitive to the ambient temperature and air flow, the requirement of the scheme on the temperature control of a vacuum system is greatly reduced, but a plurality of groups of platinum resistor measuring cavities are generally arranged on the outer surface of the shielding cavity, so that the complexity of the system in vacuum is higher, and the temperature measuring precision of the platinum resistor can be influenced in the baking process during vacuum preparation, thereby limiting the control precision of blackbody radiation frequency shift. Disclosure of Invention In order to solve the defects in the prior art, the invention provides a blackbody radiation shielding device suitable for an ultrahigh vacuum environment. The device adopts the design scheme of the embedded blackbody radiation shielding cavity, is suitable for the ultra-high vacuum environment, and can realize accurate temperature measurement and temperature control in the vacuum cavity from an air end so as to meet the ultra-high vacuum application requirement of E-9Pa magnitude of the optical clock. The above object of the present invention is achieved by the following technical means: The utility model provides a blackbody radiation shielding device suitable for ultra-high vacuum environment, including annular cavity, the circumference of annular cavity is provided with 1 pair of atomic beam import and export and 5 pair of optical windows, the bottom of annular cavity is provided with the cavity bottom plate, the top of annular cavity is provided with the chamber lid, be provided with optical windows on chamber lid and the cavity bottom plate respectively, the central axis of atomic beam import and export, the central axis of the optical window pair that annular cavity circumference set up and the central axis of the optical