JP2021022892A - Atomic oscillator and frequency signal generation system - Google Patents

Abstract

To provide an atomic oscillator that can reduce attachment of alkali metal atoms to a window.SOLUTION: An atomic oscillator includes: a light emitting element; an atomic cell that is irradiated with light emitted from the light emitting element and stores alkali metal atoms; a heater that heats the atomic cell; a container that accommodates the atomic cell and the heater and has an opening through which the light emitted from the light emitting element passes; a lid that is openable/closable and opens to open the opening and closes to close the opening; and a driving mechanism that opens and closes the lid.SELECTED DRAWING: Figure 1

Description

The present invention relates to an atomic oscillator and a frequency signal generation system.

As an oscillator having high-precision oscillation characteristics over a long period of time, an atomic oscillator that oscillates based on the energy transition of an alkali metal atom such as cesium is known. The atomic oscillator includes a light emitting device and an atomic cell in which an alkali metal atom is enclosed. The light emitted from the light emitting element passes through the window portion of the atomic cell and irradiates the alkali metal atom in the atomic cell.

In the atomic oscillator, the atomic cell is heated by a heater so that a temperature difference occurs in the atomic cell. As a result, a gaseous alkali metal atom and a liquid alkali metal atom are present in the atomic cell. Therefore, when the alkali metal atom of the gas is reduced due to the reaction with the inner wall of the atomic cell or the like, the alkali metal atom of the liquid is vaporized, and the concentration of the alkali metal atom of the gas can be kept constant.

Patent Document 1 discloses a gas cell having a main body portion having a columnar through hole and a pair of window portions sealing both openings of the through hole as a gas cell to be sealed with an alkali metal. By sealing both openings of the through holes of the main body with windows, a space in which the alkali metal gas is sealed is formed. The gas cell is housed in a shield case, and the shield case is formed with a through hole through which the excitation light irradiated to the gas cell passes. The gas cell is heated by a heater and the temperature is adjusted to a predetermined temperature.

JP-A-2015-119151

In the gas cell as described above, since the shield case is provided with a through hole through which the excitation light passes, the window portion is easily affected by the external temperature. Therefore, for example, when the energization of the heater is stopped or the energization of the heater is started, the temperature of the window portion becomes lower than that of other parts of the gas cell, and alkali metal or the like adheres to the window portion. There was a case.

When the alkali metal atom adheres to the window portion, the irradiation amount of the excitation light on the alkali metal atom changes, and the oscillation frequency of the atomic oscillator changes due to the stark shift. Further, when the alkali metal atom adheres to the window portion, the amount of light received by the light receiving element is reduced.

The present invention has been made to solve at least a part of the above-mentioned problems, and can be realized as the following aspects or application examples.

The atomic oscillator according to this application example includes a light emitting element, an atomic cell containing an alkali metal atom to which light emitted from the light emitting element is irradiated, a heater for heating the atomic cell, the atomic cell, and the atomic cell. A container containing the heater and having an opening through which light emitted from the light emitting element passes, a lid that can be opened and closed, the opening is opened by opening, and the opening is closed by closing, and the lid. Includes a drive mechanism that opens and closes.

In the atomic oscillator according to this application example, the material of the lid may be the same as the material of the container.

The atomic oscillator according to the present application example may include an elastic member located between the lid and the container when the lid is closed.

In the atomic oscillator according to the present application example, the control circuit for controlling the drive mechanism is included, and the control circuit covers the drive mechanism with the lid after a lapse of a predetermined time from the start of heating of the atomic cell by the heater. You may open it.

In the atomic oscillator according to the present application example, the control circuit may cause the drive mechanism to close the lid when the heater stops heating the atomic cell.

The atomic oscillator according to the present application example includes a control circuit for controlling the drive mechanism and a temperature sensor for detecting the temperature inside the container, and the control circuit includes the control circuit based on the detection result of the temperature sensor. When the temperature inside the container is lower than the predetermined temperature, the drive mechanism may close the lid, and when the temperature inside the container is equal to or higher than the predetermined temperature, the drive mechanism may open the lid. Good.

In the atomic oscillator according to this application example, the drive mechanism may close the lid when the energization of the drive mechanism is stopped.

The frequency signal generation system according to this application example is a frequency signal generation system including an atomic oscillator, and the atomic oscillator contains a light emitting element and an alkali metal atom to which light emitted from the light emitting element is irradiated. Atomic cell, a heater for heating the atomic cell, and a container containing the atomic cell and the heater and having an opening through which light emitted from the light emitting element passes can be opened and closed. Includes a lid that opens and closes the opening, and a drive mechanism that opens and closes the lid.

The schematic diagram which shows the atomic oscillator which concerns on 1st Embodiment. The cross-sectional view which shows typically the atomic oscillator which concerns on 1st Embodiment. The figure for demonstrating the operation of a lid. The figure for demonstrating the operation of a lid. The figure for demonstrating the operation of a drive mechanism. The figure for demonstrating the operation of a drive mechanism. The flowchart which shows an example of the processing of the control circuit at the time of starting an atomic oscillator. The flowchart which shows an example of the processing of the control circuit when the atomic oscillator is stopped. The cross-sectional view which shows typically the lid of the atomic oscillator which concerns on the 1st modification. The plan view which shows typically the lid of the atomic oscillator which concerns on 1st modification. The cross-sectional view which shows typically the atomic oscillator which concerns on the 2nd modification. The figure for demonstrating the structure of the lid of the atomic oscillator which concerns on 3rd modification. The figure for demonstrating the structure of the lid of the atomic oscillator which concerns on 3rd modification. The figure for demonstrating the structure of the lid of the atomic oscillator which concerns on 3rd modification. The figure for demonstrating the structure of the lid of the atomic oscillator which concerns on 3rd modification. The figure for demonstrating the structure of the lid of the atomic oscillator which concerns on 3rd modification. The schematic diagram which shows the atomic oscillator which concerns on 2nd Embodiment. The flowchart which shows an example of the processing of the control circuit at the time of starting an atomic oscillator. The flowchart which shows an example of the processing of the control circuit when the atomic oscillator is stopped. The figure for demonstrating an example of the frequency signal generation system which concerns on 3rd Embodiment.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the embodiments described below do not unreasonably limit the contents of the present invention described in the claims. Moreover, not all of the configurations described below are essential constituent requirements of the present invention.

1. 1. First Embodiment 1.1. Atomic oscillator 1.1.1. Outline First, the atomic oscillator according to the first embodiment will be described with reference to the drawings. FIG. 1 is a schematic view showing an atomic oscillator 100 according to the first embodiment.

When the atomic oscillator 100 simultaneously irradiates an alkali metal atom with two resonance lights having specific different wavelengths, the quantum interference effect (CPT) causes a phenomenon in which the two resonance lights are transmitted without being absorbed by the alkali metal atoms. : Coherent Population Trapping) is used as an atomic oscillator. This phenomenon due to the quantum interference effect is also called an electromagnetically induced transparency (EIT) phenomenon. The atomic oscillator according to the first embodiment may be an atomic oscillator that utilizes a double resonance phenomenon caused by light and microwaves.

As shown in FIG. 1, the atomic oscillator 100 includes a light source module 10, a neutral density filter 22, a 1/4 wave plate 24, an atomic cell 31, a light receiving element 34, a heater 35, a temperature sensor 36, and the like. It includes a coil 37, a control circuit 40, an atomic cell container 50, a lid 60, a drive mechanism 70, and an outer container 80.

The light source module 10 includes, for example, a Peltier element 11, a light emitting element 12, and a temperature sensor 13.

The light emitting element 12 emits linearly polarized light LL containing two types of light having different frequencies. The light emitting element 12 is, for example, a Vertical Cavity Surface Emitting Laser (VCSEL) or the like. The temperature sensor 13 detects the temperature of the light emitting element 12. The temperature sensor 13 is, for example, a thermistor. The Peltier element 11 controls the temperature of the light emitting element 12.

The neutral density filter 22 reduces the intensity of the light LL emitted from the light emitting element 12. The quarter wave plate 24 converts two types of light contained in the light LL having different frequencies from linearly polarized light to circularly polarized light. Although not shown, the 1/4 wave plate 24 may be located in front of the neutral density filter 22, and the light LL may be incident on the neutral density filter 22 after passing through the 1/4 wave plate 24. .. Further, a lens that makes the light LL parallel light may be arranged between the neutral density filter 22 and the quarter wave plate 24.

The atomic cell 31 irradiates the light LL emitted from the light emitting element 12. In the illustrated example, the light LL emitted from the light emitting element 12 is incident on the atomic cell 31 through the neutral density filter 22 and the quarter wave plate 24. The atomic cell 31 transmits the light LL emitted from the light emitting element 12. The atomic cell 31 contains an alkali metal atom. The alkali metal atom has an energy level of a three-level system consisting of two different basis levels and an excited level.

The light receiving element 34 detects the intensity of the light LL transmitted through the atomic cell 31 and outputs a detection signal according to the intensity of the light. The light receiving element 34 is, for example, a photodiode.

The heater 35 heats the atomic cell 31. When the heater 35 heats the atomic cell 31, the alkali metal atom is heated, and at least a part of the alkali metal atom becomes a gas state.

The temperature sensor 36 detects the temperature of the atomic cell 31. The temperature sensor 36 is, for example, a thermistor.

The coil 37 generates a magnetic field that Zeeman splits a plurality of degenerate energy levels of alkali metal atoms in the atomic cell 31. By applying a magnetic field to the alkali metal with the coil 37, the Zeeman split can widen the gap between the different degenerate energy levels of the alkali metal atom and improve the resolution. As a result, the accuracy of the oscillation frequency of the atomic oscillator 100 can be improved.

The control circuit 40 includes, for example, a temperature control circuit 41, a temperature control circuit 42, a magnetic field control circuit 43, a light source control circuit 44, and a drive mechanism control circuit 45.

The temperature control circuit 41 controls the energization of the Peltier element 11 so that the temperature of the light emitting element 12 becomes a desired temperature based on the detection result of the temperature sensor 13. The temperature control circuit 42 controls the energization of the heater 35 so that the inside of the atomic cell 31 has a desired temperature based on the detection result of the temperature sensor 36. The magnetic field control circuit 43 controls the energization of the coil 37 so that the magnetic field generated by the coil 37 is constant.

The light source control circuit 44 controls the frequencies of two types of light contained in the light LL emitted from the light emitting element 12 so that the EIT phenomenon occurs based on the detection result of the light receiving element 34. Here, the EIT phenomenon occurs when these two types of light become a resonance light pair having a frequency difference corresponding to an energy difference between two base levels of an alkali metal atom housed in an atomic cell 31. The light source control circuit 44 includes a voltage controlled oscillator (VCO) whose oscillation frequency is controlled so as to stabilize in synchronization with the control of two types of light frequencies, and this voltage controlled oscillator. Is output as a clock signal of the atomic oscillator 100.

The drive mechanism control circuit 45 controls the drive mechanism 70. The drive mechanism control circuit 45 drives the drive mechanism 70 when the lid 60 is opened and the heater 35 stops heating the atomic cell 31 after a lapse of a predetermined time after the heater 35 starts heating the atomic cell 31. Let the mechanism 70 close the lid 60. The details of the control of the drive mechanism 70 by the drive mechanism control circuit 45 will be described in "1.1.3. Operation" described later.

The control circuit 40 is provided, for example, on an IC (Integrated Circuit) chip mounted on a substrate (not shown) housed in an outer container 80. The control circuit 40 may be a single IC, or may be a combination of a plurality of digital circuits or analog circuits.

The atomic cell container 50 houses the atomic cell 31. In addition to the atomic cell 31, the atomic cell container 50 houses, for example, a neutral density filter 22, a quarter wave plate 24, a light receiving element 34, a heater 35, a temperature sensor 36, and a coil 37. The atomic cell container 50 has an opening through which the light LL emitted from the light emitting element 12 passes.

The lid 60 is configured to be openable and closable. The opening of the atomic cell container 50 is closed by closing the lid 60, and the opening of the atomic cell container 50 is opened by opening the lid 60. The lid 60 is opened and closed by the drive mechanism 70.

The outer container 80 houses the light source module 10, the control circuit 40, the atomic cell container 50, the lid 60, and the drive mechanism 70.

1.1.2. Specific Configuration Next, a specific configuration of the atomic oscillator 100 will be described. FIG. 2 is a cross-sectional view schematically showing the atomic oscillator 100. Note that FIG. 2 illustrates a state in which the lid 60 is closed.

As shown in FIG. 2, the atomic oscillator 100 includes, for example, a light source module 10, a neutral density filter 22, a 1/4 wave plate 24, an atomic cell 31, a first holding member 32, and a second holding member 33. The light receiving element 34, the heater 35, the temperature sensor 36, the atomic cell container 50, the lid 60, and the outer container 80 are included.

The light source module 10 is arranged on the base 82 of the outer container 80. The light source module 10 includes, for example, a light emitting element 12, a submount 14, and a light source container 15. For convenience, the Peltier element 11 and the temperature sensor 13 are not shown in FIG.

A light emitting element 12 is arranged on the submount 14. The submount 14 can release the heat of the light emitting element 12 to the outside of the light source module 10.

The light source container 15 houses the light emitting element 12 and the submount 14. The light source container 15 is arranged on the substrate 82 of the outer container 80. The light source container 15 is provided with an opening 15a through which the light LL emitted from the light emitting element 12 passes. The opening 15a may be filled with a member that transmits light LL.

With the lid 60 open, the light LL emitted from the light emitting element 12 has an opening 15a of the light source container 15, an opening 54a of the second container 54, an opening 52a of the first container 52, a neutral density filter 22, and 1 It passes through the / 4 wavelength plate 24 and is incident on the window portion 2a of the atomic cell 31.

The atomic cell 31 contains alkali metal atoms such as cesium, rubidium, and sodium. In the atomic cell 31, for example, the saturated vapor pressure of the alkali metal atom is set, and a gaseous alkali metal atom and a liquid alkali metal atom are present. As a result, when the alkali metal atom of the gas is reduced due to the reaction with the inner wall of the atomic cell 31, the alkali metal atom of the liquid is vaporized, and the concentration of the alkali metal atom of the gas can be kept constant.

The atomic cell 31 has, for example, a first member 31a, a second member 31b, and a third member 31c.

The first member 31a is a plate-shaped member. The first member 31a has a window portion 2a that transmits light LL emitted from the light emitting element 12. The window portion 2a is a portion that overlaps with the opening 32a provided in the first holding member 32 when viewed along the traveling direction of the light LL. The material of the first member 31a is, for example, glass.

The second member 31b is a plate-shaped member. The second member 31b has a window portion 2b that transmits the light LL emitted from the light emitting element 12. The window portion 2b is a portion that overlaps with the opening 32b provided in the first holding member 32 when viewed along the traveling direction of the light LL. The material of the second member 31b is, for example, glass. The light LL enters the atomic cell 31 from the window portion 2a and is emitted from the window portion 2b.

The third member 31c connects the first member 31a and the second member 31b. The third member 31c has a through hole, one opening of the through hole is closed by the first member 31a, and the other opening of the through hole is closed by the second member 31b. As a result, a space for accommodating the alkali metal is formed. Although not shown, the atomic cell 31 has a first alkali metal accommodating chamber through which the light LL emitted from the light emitting element 12 passes and accommodating a gaseous alkali metal, and a second alkali accommodating a liquid alkali metal. It may have a metal storage chamber and a passage connecting the first alkali metal storage chamber and the second alkali metal storage chamber. The outer shape of the third member 31c is, for example, a rectangular parallelepiped. The material of the third member 31c is, for example, glass or silicon.

The first holding member 32 and the second holding member 33 hold the atomic cell 31. The first holding member 32 transfers the heat of the heater 35 to the atomic cell 31. The first holding member 32 covers a part of the atomic cell 31. The first holding member 32 covers, for example, the first alkali metal accommodating chamber of the atomic cell 31.

The first holding member 32 is provided with an opening 32a. The light LL emitted from the light emitting element 12 passes through the opening 32a and enters the window portion 2a of the atomic cell 31. In the illustrated example, the neutral density filter 22 and the 1/4 wave plate 24 are arranged in the opening 32a. The first holding member 32 is provided with an opening 32b. The light LL emitted from the window portion 2b of the atomic cell 31 passes through the opening 32b and enters the light receiving element 34.

The second holding member 33 is a part of the atomic cell 31 and covers the portion not covered by the first holding member 32. The second holding member 33 covers, for example, the second alkali metal accommodating chamber of the atomic cell 31. In the atomic cell 31, the temperature of the portion covered by the second holding member 33 is lower than, for example, the temperature of the portion covered by the first holding member 32. Therefore, the liquid alkali metal atom can exist in or near the portion covered by the second holding member 33. The materials of the first holding member 32 and the second holding member 33 are, for example, aluminum, titanium, copper, brass and the like.

The light receiving element 34 is arranged on the opposite side of the atomic cell 31 from the light emitting element 12. In the illustrated example, the light receiving element 34 is arranged on the first holding member 32 via the connecting member 6. The light receiving element 34 overlaps with the opening 32b when viewed along the traveling direction of the light LL. The light receiving element 34 is electrically connected to the control circuit 40.

The heater 35 is connected to the first holding member 32. The heater 35 heats the atomic cell 31 via the first holding member 32.

The temperature sensor 36 is connected to the first holding member 32. The temperature sensor 36 indirectly detects the temperature of the atomic cell 31 by detecting the temperature of the first holding member 32, for example. Although not shown, the temperature sensor 36 may be connected to the atomic cell 31 and directly detect the temperature of the atomic cell 31.

Although not shown in FIG. 2, the coil 37 is, for example, a solenoid-type coil provided by winding along the outer circumference of the atomic cell 31, or a pair of Helmholtz-type coils facing each other via the atomic cell 31. It is a coil of. The coil 37 generates a magnetic field in the atomic cell 31 along the traveling direction of the light LL. As a result, the gap between the different degenerate energy levels of the alkali metal atoms contained in the atomic cell 31 can be widened by Zeeman splitting to improve the resolution and reduce the line width of the EIT signal.

The atomic cell container 50 houses the atomic cell 31 and the heater 35. In the example shown in FIG. 2, in addition to the atomic cell 31, the atomic cell container 50 includes a neutral density filter 22, a 1/4 wave plate 24, a first holding member 32, a second holding member 33, a light receiving element 34, and a heater 35. , A temperature sensor 36, and a coil 37 (not shown).

The atomic cell container 50 has a first container 52 and a second container 54.

The first container 52 forms a space in which the atomic cell 31 and the like are housed. The first container 52 has, for example, a substantially rectangular parallelepiped outer shape. The first container 52 has an opening 52a through which the light LL emitted from the light emitting element 12 passes. The material of the first container 52 is, for example, permalloy, silicon iron, or the like. By using such a material, the first container 52 can shield the magnetic field from the outside.

The first container 52 is supported by the first spacer 502. The first spacer 502 is arranged between the first container 52 and the second container 54. The material of the first spacer 502 is, for example, resin.

The second container 54 houses the first container 52 and the first spacer 502. The second container 54 has, for example, a substantially rectangular parallelepiped outer shape. The second container 54 has an opening 54a through which the light LL emitted from the light emitting element 12 passes. The opening 54a of the second container 54 overlaps with the opening 52a of the first container 52 when viewed along the traveling direction of the light LL. The material of the second container 54 is, for example, the same as the material of the first container 52. Therefore, the second container 54 can shield the magnetic field from the outside.

The first container 52 and the second container 54 are arranged apart from each other, for example. Therefore, as compared with the case where the first container 52 and the second container 54 are in contact with each other, the function of shielding the magnetic field from the outside can be enhanced.

The second container 54 is supported by the second spacer 504. The second spacer 504 is arranged between the second container 54 and the base 82 of the outer container 80. The material of the second spacer 504 is, for example, the same as the material of the first spacer 502.

In the example shown in FIG. 2, the atomic cell container 50 has a first container 52 and a second container 54, and the atomic cell 31 is doubly surrounded by the two containers, but the atomic cell container 50 It may have only one container and surround the atomic cell 31 with one container.

The outer container 80 has a base 82 and a lid 84. The material of the outer container 80 is, for example, permalloy, silicon iron, or the like. By using such a material, the outer container 80 can shield the magnetic field from the outside.

The lid 60 is configured to be openable and closable, and the opening 54a is opened when the lid 60 is opened, and the opening 54a is closed when the lid 60 is closed. The material of the lid 60 is, for example, the same as the material of the atomic cell container 50. The material of the lid 60 may be different from the material of the atomic cell container 50.

3 and 4 are diagrams for explaining the operation of the lid 60. FIG. 3 shows a state in which the lid 60 is closed, and FIG. 4 shows a state in which the lid 60 is open. Note that, for convenience, only the lid 60 and the second container 54 are shown in FIGS. 3 and 4.

As shown in FIGS. 3 and 4, the lid 60 is configured to be movable between a first position P1 that covers the opening 54a and a second position P2 that does not cover the opening 54a. The lid 60 is closed by positioning the lid 60 at the first position P1, and the lid 60 is opened by positioning the lid 60 at the second position P2. The second position P2 is not particularly limited and can be set at any position. The movement of the lid 60 is performed by the drive mechanism 70.

The drive mechanism 70 is housed in the outer container 80. The drive mechanism 70 is not housed in the atomic cell container 50, but is arranged outside the atomic cell container 50. Therefore, the influence of the magnetic field and the electric field generated by the drive mechanism 70 on the atomic cell 31 can be reduced. The drive mechanism 70 may be arranged inside the atomic cell container 50.

5 and 6 are diagrams for explaining the operation of the drive mechanism 70. FIG. 5 illustrates a state in which the drive mechanism 70 positions the lid 60 at the first position P1, and FIG. 6 illustrates a state in which the drive mechanism 70 positions the lid 60 at the second position P2.

As shown in FIGS. 5 and 6, the drive mechanism 70 has a moving device 71 that linearly moves the lid 60. The moving device 71 has, for example, an air cylinder. Specifically, the moving device 71 is arranged in the cylinder pipe 72, the cylinder pipe 72, and the piston 73 that moves in the axial direction, the rod 74 connected to the piston 73, and the rod 74 penetrate through the cylinder pipe 72. It has a flange 75 that closes one end of the cylinder pipe 72, a flange 76 that closes the other end of the cylinder pipe 72, a pipe 77 attached to the flange 76 for introducing and discharging compressed air, and a spring 78.

The moving device 71 has a first chamber 79a surrounded by a cylinder pipe 72, a piston 73, and a flange 76, and a second chamber 79b surrounded by a cylinder pipe 72, a piston 73, and a flange 75. .. Compressed air is introduced and discharged from the pipe 77 into the first chamber 79a, and a spring 78 is arranged in the second chamber 79b. Compressed air is supplied from a compressor (not shown). A lid 60 is attached to the tip of the rod 74.

For example, when compressed air is introduced into the first chamber 79a in a state where the compressed air is not introduced into the first chamber 79a shown in FIG. 5, the piston 73 is flanged by the force of the compressed air as shown in FIG. It moves to the 75 side and the rod 74 extends. As a result, the lid 60 moves from the first position P1 to the second position P2. That is, the lid 60 opens. The rod 74 is attached to the lid 60 so that the rod 74 does not overlap with the opening 54a even when the lid 60 is open. In the illustrated example, the rod 74 is attached to the top of the lid 60. Therefore, even when the lid 60 is open, the rod 74 does not overlap with the opening 54a, and it is possible to prevent the rod 74 from blocking the light LL passing through the opening 54a.

When the compressed air is discharged in the state shown in FIG. 6, as shown in FIG. 5, the piston 73 moves toward the flange 76 by the force of the spring 78, and the rod 74 contracts. As a result, the lid 60 moves from the second position P2 to the first position P1. That is, the lid 60 closes.

Here, when the energization of the drive mechanism 70 is stopped, that is, when the supply of electric power to the drive mechanism 70 is stopped, the operation of the compressor is stopped and the supply of compressed air is stopped. Therefore, the lid 60 is located at the first position P1 by the force of the spring 78 without introducing the compressed air into the first chamber 79a. That is, even when the lid 60 is in the second position P2, the lid 60 moves to the first position P1 when the energization of the drive mechanism 70 is stopped. In this way, when the energization of the drive mechanism 70 is stopped, the drive mechanism 70 moves the lid 60 to the first position P1 regardless of the position of the lid 60 when the energization is stopped. That is, when the energization of the drive mechanism 70 is stopped, the drive mechanism 70 closes the lid 60.

In the above, the case where the drive mechanism 70 has a moving device 71 using an air cylinder has been described, but the configuration of the drive mechanism 70 is not particularly limited as long as the lid 60 can be moved. For example, the drive mechanism 70 may have a device having a motor and a mechanism for converting the rotational motion of the motor into a linear motion. Examples of the mechanism for converting the rotary motion into the linear motion include a mechanism using a belt and a pulley, a mechanism using a ball screw, and the like.

Further, in the above description, the case where the moving device 71 closes the lid 60 by the force of the spring 78 when the energization to the drive mechanism 70 is stopped has been described, but the method of closing the lid 60 when the energization is stopped is described. Is not limited to this.

1.1.3. Operation Next, the operation of the atomic oscillator 100 will be described. Here, the control of the lid 60 by the control circuit 40 will be described.

First, the control of the lid 60 when starting the atomic oscillator 100 will be described. FIG. 7 is a flowchart showing an example of processing of the control circuit 40 when starting the atomic oscillator 100.

When an ON signal for starting the atomic oscillator 100 is input to the control circuit 40 from an external device (not shown), the temperature control circuit 42 sends the heater 35 to a desired temperature so that the inside of the atomic cell 31 becomes a desired temperature. Energization is started (S10). That is, the temperature control circuit 42 starts heating the atomic cell 31. Since the energization of the drive mechanism 70 is stopped before the ON signal is input, the lid 60 is in a closed state.

The control circuit 40 starts measuring the time at the timing when the heater 35 starts heating the atomic cell 31 (S12), and the drive mechanism control circuit 45 elapses a predetermined time after the heater 35 starts heating the atomic cell 31. (No in S14), and after a predetermined time has elapsed (Yes in S14), the drive mechanism 70 is made to open the lid 60 (S16).

Here, in the atomic oscillator 100, the atomic cell 31 is maintained at a constant temperature by the heater 35 in order to improve the frequency stability. The predetermined time is, for example, the time when the atomic cell 31 reaches the constant temperature. The predetermined time can be determined by conducting an experiment or the like in advance.

The control circuit 40 causes the drive mechanism 70 to open the lid 60, and then ends the control of the lid 60 when the atomic oscillator 100 is started.

When the lid 60 is opened by the above process, the atomic oscillator 100 starts outputting a clock signal. That is, when the lid 60 is opened, the temperature control circuit 41, the temperature control circuit 42, the magnetic field control circuit 43, and the light source control circuit 44 operate as described above, and a clock signal is output.

Next, the control of the lid 60 when the atomic oscillator 100 is stopped will be described. FIG. 8 is a flowchart showing an example of processing of the control circuit 40 when the atomic oscillator 100 is stopped.

When an OFF signal for stopping the atomic oscillator 100 is input to the control circuit 40 from an external device (not shown), the atomic oscillator 100 stops the output of the clock signal, and the temperature control circuit 42 stops energizing the heater 35. (S20). That is, the temperature control circuit 42 stops heating the atomic cell 31. Before the OFF signal is input, the lid 60 is in the open state.

When the OFF signal is input to the drive mechanism control circuit 45 and the temperature control circuit 42 stops energizing the heater 35, the drive mechanism 70 causes the drive mechanism 70 to close the lid 60 (S22). In the drive mechanism control circuit 45, for example, the temperature control circuit 42 stops energizing the heater 35, and at the same time, stops energizing the drive mechanism 70, causing the drive mechanism 70 to close the lid 60. The drive mechanism control circuit 45 may have the drive mechanism 70 close the lid 60 after a predetermined time has elapsed after the temperature control circuit 42 stopped energizing the heater 35.

After the drive mechanism 70 closes the lid 60, the control circuit 40 ends the control of the lid 60 when the atomic oscillator 100 is stopped.

1.1.4. Effect The atomic oscillator 100 has the following effects, for example.

The atomic oscillator 100 accommodates an atomic cell 31 and a heater 35, and is openable and closable with a second container 54 having an opening 54a through which light LL emitted from the light emitting element 12 passes, and the opening 54a opens when opened. A lid 60 that closes the opening 54a by closing, and a drive mechanism 70 that opens and closes the lid 60 are included. Therefore, in the atomic oscillator 100, the temperature of the atomic cell 31 is not kept constant by the heater 35, such as when the energization of the heater 35 is stopped or when the energization of the heater 35 is started, and the temperature of the atomic cell 31 is increased. If it fluctuates, the temperature drop of the window portion 2a can be reduced by closing the lid 60. As a result, it is possible to reduce the adhesion of the alkali metal to the window portion 2a caused by the temperature of the window portion 2a of the atomic cell 31 being lower than that of the other portions of the atomic cell 31.

Here, the first container 52 and the second container 54 each have an opening for passing the light LL emitted from the light emitting element 12, that is, an opening 52a and an opening 54a. Therefore, when the lid 60 is not provided, the window portion 2a in the atomic cell 31 is easily affected by the external temperature. Therefore, when the temperature of the atomic cell 31 is not kept constant, such as when the energization of the heater 35 is stopped or when the energization of the heater 35 is started, the temperature of the window portion 2a is other than that of the atomic cell 31. There is a case where the alkali metal adheres to the window portion 2a at a temperature lower than the temperature of the portion.

Since the atomic oscillator 100 has the lid 60 as described above, the temperature drop of the window portion 2a due to the influence of the external temperature can be reduced by closing the lid 60. Therefore, in the atomic oscillator 100, the adhesion of the alkali metal to the window portion 2a can be reduced.

In the atomic oscillator 100, the material of the lid 60 is the same as the material of the second container 54. Therefore, in the atomic oscillator 100, the temperature distribution in the second container 54 can be made uniform as compared with the case where the material of the lid 60 is different from the material of the second container 54. Therefore, the temperature distribution of the atomic cells 31 can be made uniform, and the adhesion of the alkali metal to the window portion 2a can be reduced. The material of the lid 60 may be a material having a low thermal conductivity. As a result, the influence of the external temperature inside the second container 54 can be reduced. Further, the material of the lid 60 may be a material having high thermal conductivity. As a result, the temperature difference between the second container 54 and the lid 60 can be reduced, and the temperature inside the second container 54 can be made uniform.

The atomic oscillator 100 includes a control circuit 40 that controls the drive mechanism 70, and the control circuit 40 causes the drive mechanism 70 to open the lid 60 after a lapse of a predetermined time after the heater 35 starts heating the atomic cell 31. Therefore, in the atomic oscillator 100, the temperature of the window portion 2a is lowered due to the influence of the external temperature between the time when the heater 35 starts heating the atomic cell 31 and the time when the temperature of the atomic cell 31 is maintained constant. Can be reduced. Therefore, in the atomic oscillator 100, the adhesion of the alkali metal to the window portion 2a can be reduced.

In the atomic oscillator 100, the control circuit 40 causes the drive mechanism 70 to close the lid 60 when the heater 35 stops heating the atomic cell 31. Therefore, in the atomic oscillator 100, it is possible to reduce the decrease in temperature of the window portion 2a due to the influence of the external temperature after the heater 35 stops heating the atomic cell 31. Therefore, in the atomic oscillator 100, the adhesion of the alkali metal to the window portion 2a can be reduced.

In the atomic oscillator 100, the drive mechanism 70 closes the lid 60 when the energization of the drive mechanism 70 is stopped. Therefore, in the atomic oscillator 100, the lid 60 is closed even when the supply of electric power to the atomic oscillator 100 is unexpectedly stopped due to, for example, a power failure. Therefore, even when the supply of electric power to the atomic oscillator 100 is stopped and the heater 35 stops heating the atomic cell 31, the adhesion of the alkali metal to the window portion 2a can be reduced.

1.2. Deformation Example of Atomic Oscillator Next, a modification of the atomic oscillator according to the first embodiment will be described with reference to the drawings. Hereinafter, points different from the example of the atomic oscillator 100 shown in FIGS. 1 to 6 described above will be described, and description of the same points will be omitted.

1.2.1. First Modified Example FIG. 9 is a cross-sectional view schematically showing a lid 60 of the atomic oscillator 100 according to the first modified example. FIG. 10 is a plan view schematically showing a lid 60 of the atomic oscillator 100 according to the first modification. Note that FIG. 10 is a view of the lid 60 as viewed from the direction A shown in FIG. The A direction is a direction along the traveling direction of the light LL emitted from the light emitting element 12.

As shown in FIGS. 9 and 10, when the lid 60 is closed, the elastic member 62 is located between the lid 60 and the second container 54.

The elastic member 62 is fixed to the lid 60. That is, the elastic member 62 moves with the movement of the lid 60. The elastic member 62 is provided along the outer edge of the lid 60. As shown in FIG. 10, when the lid 60 is closed, the elastic member 62 is arranged so as to surround the opening 54a. The material of the elastic member 62 is, for example, sponge, rubber, or the like. The elastic member 62 is softer than, for example, the lid 60. The elastic member 62 can close the gap formed between the lid 60 and the second container 54 when the lid 60 is closed. As a result, it is possible to reduce the decrease in temperature of the window portion 2a due to the influence of the external temperature. Therefore, the adhesion of the alkali metal to the window portion 2a can be reduced.

Although the case where the elastic member 62 is fixed to the lid 60 has been described above, the elastic member 62 may be fixed to the second container 54.

1.2.2. Second Modified Example FIG. 11 is a cross-sectional view schematically showing the atomic oscillator 100 according to the second modified example. Note that FIG. 11 illustrates a state in which the lid 60 is closed.

In the example shown in FIG. 2 described above, the case where the lid 60 opens and closes the opening 54a of the second container 54 has been described, but as shown in FIG. 11, the lid 60 opens and closes the opening 52a of the first container 52. You may. As shown in FIG. 11, even when the lid 60 opens and closes the opening 52a of the first container 52, the same action and effect as in the case shown in FIG. 2 described above can be obtained. Although not shown, the atomic oscillator 100 may have a lid 60 for opening and closing the opening 52a of the first container 52 and a lid 60 for opening and closing the opening 54a of the second container 54.

1.2.3. Third Modification Example In the first embodiment described above, the lid 60 is opened and closed by moving the lid 60 between the first position P1 and the second position P2 by the drive mechanism 70, but the lid 60 is opened and closed. The method is not limited to this.

12 to 16 are views for explaining the configuration of the lid 60 of the atomic oscillator according to the third modification. Note that FIGS. 12 to 15 correspond to FIG. 10.

For example, as shown in FIGS. 12 and 13, the lid 60 may be opened and closed by rotating the lid 60 around the shaft 64. In this case, the drive mechanism 70 may include a motor that rotates the shaft 64.

Further, for example, as shown in FIG. 14, the lid 60 may be a diaphragm device in which a plurality of diaphragm blades 66 are arranged on the circumference and the opening 54a is opened and closed by the rotation of each diaphragm blade 66. Note that FIG. 14 shows a state in which the lid 60 is closed.

Further, for example, as shown in FIG. 15, the lid 60 may have a first portion 60a and a second portion 60b. The first portion 60a is configured to be rotatable around a shaft 64a. The second portion 60b is configured to be rotatable around a shaft 64b. The opening 54a can be closed by the first portion 60a closing a portion of the opening 54a and the second portion 60b closing the other portion of the opening 54a.

As shown in FIG. 16, the first portion 60a and the second portion 60b may be configured so that they partially overlap each other when the lid 60 is closed. As a result, the gap between the first portion 60a and the second portion 60b can be closed.

Further, in the examples shown in FIGS. 5 and 6 above, the case where the power for opening and closing the lid 60 is an air cylinder has been described, but the power for opening and closing the lid 60 is not limited to this. For example, the power for opening and closing the lid 60 may be a power source using a sword, water pressure or hydraulic pressure, or a power source using compression or expansion of gas due to a temperature change in the atomic cell container 50.

2. 2. Second Embodiment 2.1. Atomic Oscillator Next, the atomic oscillator according to the second embodiment will be described with reference to the drawings. FIG. 17 is a schematic view showing the atomic oscillator 200 according to the second embodiment.

Hereinafter, in the atomic oscillator 200 according to the second embodiment, the members having the same functions as the constituent members of the atomic oscillator 100 according to the first embodiment described above are designated by the same reference numerals, and detailed description thereof will be omitted. ..

In the atomic oscillator 100 described above, the drive mechanism control circuit 45 causes the drive mechanism 70 to open the lid 60 after a lapse of a predetermined time after the heater 35 starts heating the atomic cell 31, and the heater 35 heats the atomic cell 31. When stopped, the drive mechanism 70 closed the lid 60.

On the other hand, the atomic oscillator 200 includes a temperature sensor 202 that detects the temperature inside the atomic cell container 50, and the drive mechanism control circuit 45 has the temperature inside the atomic cell container 50 based on the detection result of the temperature sensor 202. The lid 60 is closed by the drive mechanism 70 when the temperature is below the predetermined temperature, and the lid 60 is opened by the drive mechanism 70 when the temperature inside the atomic cell container 50 is equal to or higher than the predetermined temperature.

The temperature sensor 202 detects the temperature inside the atomic cell container 50. The temperature sensor 202 may detect the temperature inside the atomic cell container 50 via another member. The temperature sensor 202 is housed in the first container 52 shown in FIG. The position of the temperature sensor 202 is not particularly limited, but in order to detect the temperature inside the atomic cell container 50 more accurately, for example, it is farther from the atomic cell 31 than the temperature sensor 36 that detects the temperature of the atomic cell 31. It is placed in position. Although not shown, the temperature sensor 36 may be used as the temperature sensor 202. That is, the temperature sensor 36 may be used to detect the temperature inside the atomic cell container 50.

2.2. Operation Next, the operation of the atomic oscillator 200 will be described. Here, the control of the lid 60 by the control circuit 40 will be described.

First, the control of the lid 60 when starting the atomic oscillator 200 will be described. FIG. 18 is a flowchart showing an example of processing of the control circuit 40 when starting the atomic oscillator 200.

When an ON signal is input to the control circuit 40 from an external device (not shown), the temperature control circuit 42 starts energizing the heater 35 so that the temperature inside the atomic cell 31 becomes a desired temperature (S30). That is, the temperature control circuit 42 starts heating the atomic cell 31. Before the ON signal is input, the drive mechanism 70 is not energized, so the lid 60 is in a closed state.

The drive mechanism control circuit 45 acquires the temperature detection result in the atomic cell container 50 by the temperature sensor 202, and based on the temperature detection result in the atomic cell container 50 by the temperature sensor 202, the inside of the atomic cell container 50. It is determined whether or not the temperature of is equal to or higher than a predetermined temperature (S32). The drive mechanism control circuit 45 waits until the temperature inside the atomic cell container 50 is determined to be equal to or higher than the predetermined temperature (No in S32), and when the temperature inside the atomic cell container 50 is determined to be equal to or higher than the predetermined temperature (S32). Yes), the drive mechanism 70 is made to open the lid 60 (S34).

Here, in the atomic oscillator 200, the atomic cell 31 is maintained at a constant temperature by the heater 35 in order to improve the frequency stability. The predetermined temperature is, for example, the constant temperature. The predetermined temperature is not limited to the constant temperature, and can be set to any temperature as long as the adhesion of the alkali metal to the window portion 2a can be reduced.

The control circuit 40 causes the drive mechanism 70 to open the lid 60, and then ends the control of the lid 60 when the atomic oscillator 200 is started.

When the lid 60 is opened by the above process, the atomic oscillator 200 starts outputting a clock signal. That is, when the lid 60 is opened, the temperature control circuit 41, the temperature control circuit 42, the magnetic field control circuit 43, and the light source control circuit 44 operate as described above, and a clock signal is output.

Next, the control of the lid 60 when the atomic oscillator 200 is stopped will be described. FIG. 19 is a flowchart showing an example of processing of the control circuit 40 when the atomic oscillator 200 is stopped.

When an OFF signal is input to the control circuit 40 from an external device (not shown), the atomic oscillator 200 stops outputting the clock signal, and the temperature control circuit 42 stops energizing the heater 35 (S40). That is, the temperature control circuit 42 stops heating the atomic cell 31. Before the OFF signal is input, the lid 60 is in the open state.

The drive mechanism control circuit 45 acquires the temperature detection result in the atomic cell container 50 by the temperature sensor 202, and based on the temperature detection result in the atomic cell container 50 by the temperature sensor 202, the inside of the atomic cell container 50. It is determined whether or not the temperature of the above temperature is lower than the predetermined temperature (S42). The drive mechanism control circuit 45 waits until the temperature inside the atomic cell container 50 is determined to be lower than the predetermined temperature (No in S42), and when the temperature inside the atomic cell container 50 is determined to be lower than the predetermined temperature (S42). Yes), the drive mechanism 70 is made to close the lid 60 (S44). The predetermined temperature is the same as the predetermined temperature in the process of step S32 described above.

After the drive mechanism 70 closes the lid 60, the control circuit 40 ends the control of the lid 60 when the atomic oscillator 100 is stopped.

2.3. Effect The atomic oscillator 200 includes a control circuit 40 that controls the drive mechanism 70, and the control circuit 40 determines the temperature inside the atomic cell container 50 based on the detection result of the temperature inside the atomic cell container 50 by the temperature sensor 202. When the temperature is lower than the predetermined temperature, the drive mechanism 70 closes the lid 60, and when the temperature inside the atomic cell container 50 is equal to or higher than the predetermined temperature, the drive mechanism 70 opens the lid 60. Therefore, in the atomic oscillator 200, the temperature drop of the window portion 2a due to the influence of the external temperature can be reduced. Therefore, in the atomic oscillator 200, the adhesion of the alkali metal to the window portion 2a can be reduced.

3. 3. Third Embodiment Next, the frequency signal generation system according to the third embodiment will be described with reference to the drawings. The following clock transmission system as a timing server is an example of a frequency signal generation system. FIG. 20 is a schematic configuration diagram showing a clock transmission system 900.

The clock transmission system 900 includes the atomic oscillator 100 according to the first embodiment.

The clock transmission system 900 is a system that matches the clocks of each device in the time division multiplexing network, and has an N (Normal) system and an E (Emergency) system redundant configuration.

As shown in FIG. 20, the clock transmission system 900 includes a clock supply device 901 and an SDH (Synchronous Digital Hierarchy) device 902 of station A, a clock supply device 903 and SDH device 904 of station B, and a clock supply device of station C. 905 and SDH devices 906 and 907 are provided. The clock supply device 901 has an atomic oscillator 100 and generates an N-system clock signal. The clock supply device 901 has a terminal 910 into which a frequency signal from the atomic oscillator 100 is input. The atomic oscillator 100 in the clock supply device 901 generates a clock signal in synchronization with a more accurate clock signal from the master clocks 908 and 909 including the atomic oscillator using cesium.

The SDH device 902 transmits and receives a main signal based on the clock signal from the clock supply device 901, superimposes the N system clock signal on the main signal, and transmits the N system clock signal to the lower clock supply device 905. The clock supply device 903 has an atomic oscillator 100 and generates an E-system clock signal. The clock supply device 903 has a terminal 911 into which a frequency signal from the atomic oscillator 100 is input. The atomic oscillator 100 in the clock supply device 903 generates a clock signal in synchronization with a more accurate clock signal from the master clocks 908 and 909 including the atomic oscillator using cesium.

The SDH device 904 transmits and receives a main signal based on the clock signal from the clock supply device 903, superimposes the E system clock signal on the main signal, and transmits the clock signal to the lower clock supply device 905. The clock supply device 905 receives the clock signals from the clock supply devices 901 and 903, and generates a clock signal in synchronization with the received clock signal.

The clock supply device 905 usually generates a clock signal in synchronization with the N-system clock signal from the clock supply device 901. Then, when an abnormality occurs in the N system, the clock supply device 905 generates a clock signal in synchronization with the clock signal of the E system from the clock supply device 903. By switching from the N system to the E system in this way, stable clock supply can be ensured and the reliability of the clock path network can be improved. The SDH device 906 transmits and receives a main signal based on the clock signal from the clock supply device 905. Similarly, the SDH device 907 transmits and receives a main signal based on the clock signal from the clock supply device 905. As a result, the device of station C can be synchronized with the device of station A or station B.

The frequency signal generation system according to the third embodiment is not limited to the clock transmission system. The frequency signal generation system includes a system in which an atomic oscillator is mounted and is composed of various devices and a plurality of devices that utilize the frequency signal of the atomic oscillator. The frequency signal generation system includes a control unit that controls an atomic oscillator.

The frequency signal generation system according to the third embodiment includes, for example, a liquid discharge device such as a smartphone, a tablet terminal, a clock, a mobile phone, a digital still camera, an inkjet printer, a personal computer, a television, a video camera, a video tape recorder, and a car navigation system. Equipment, pagers, electronic notebooks, electronic dictionaries, calculators, electronic game equipment, word processors, workstations, videophones, security TV monitors, electronic binoculars, POS (point of sales) terminals, medical equipment, fish finder, GNSS (Global) Navigation Satellite System) It may be a frequency standard, various measuring devices, instruments, a flight simulator, a terrestrial digital broadcasting system, a mobile phone base station, or a mobile body.

Examples of the medical device include an electronic thermometer, a sphygmomanometer, a blood glucose meter, an electrocardiogram measuring device, an ultrasonic diagnostic device, an electronic endoscope, and a magnetocardiograph. Examples of the above-mentioned instruments include instruments such as automobiles, aircrafts, and ships. Examples of the moving body include automobiles, aircrafts, ships and the like.

In the present invention, some configurations may be omitted, or each embodiment or modification may be combined within the range having the features and effects described in the present application.

The present invention is not limited to the above-described embodiment, and various modifications are possible. For example, the present invention includes substantially the same configuration as that described in the embodiments. A substantially identical configuration is, for example, a configuration having the same function, method, and result, or a configuration having the same purpose and effect. The present invention also includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. The present invention also includes a configuration that exhibits the same effects as the configuration described in the embodiment or a configuration that can achieve the same object. The present invention also includes a configuration in which a known technique is added to the configuration described in the embodiment.

2a ... window part, 2b ... window part, 6 ... connection member, 10 ... light source module, 11 ... Perche element, 12 ... light emitting element, 13 ... temperature sensor, 14 ... submount, 15 ... light source container, 15a ... opening, 22 ... Dimming filter, 24 ... 1/4 wavelength plate, 31 ... Atomic cell, 31a ... First member, 31b ... Second member, 31c ... Third member, 32 ... First holding member, 32a ... Opening, 32b ... Opening , 33 ... 2nd holding member, 34 ... light receiving element, 35 ... heater, 36 ... temperature sensor, 37 ... coil, 40 ... control circuit, 41 ... temperature control circuit, 42 ... temperature control circuit, 43 ... magnetic field control circuit, 44 ... light source control circuit, 45 ... drive mechanism control circuit, 50 ... atomic cell container, 52 ... first container, 52a ... opening, 54 ... second container, 54a ... opening, 60 ... lid, 60a ... first part, 60b ... Second part, 62 ... elastic member, 64 ... shaft, 64a ... shaft, 64b ... shaft, 66 ... throttle blade, 70 ... drive mechanism, 71 ... moving device, 72 ... cylinder tube, 73 ... piston, 74 ... rod, 75 ... Flange, 76 ... Flange, 77 ... Tube, 78 ... Spring, 79a ... First chamber, 79b ... Second chamber, 80 ... Outer container, 82 ... Base, 84 ... Lid, 100 ... Atomic oscillator, 200 ... Atomic oscillator , 202 ... Temperature sensor, 502 ... First spacer, 504 ... Second spacer, 900 ... Clock transmission system, 901 ... Clock supply device, 902 ... SDH device, 903 ... Clock supply device, 904 ... SDH device, 905 ... Clock supply Device, 906 ... SDH device, 907 ... SDH device, 908 ... master clock, 909 ... master clock, 910 ... terminal, 911 ... terminal

Claims (8)

Light emitting element and
An atomic cell containing an alkali metal atom, which is irradiated with the light emitted from the light emitting element, and
A heater that heats the atomic cell and
A container containing the atomic cell and the heater and having an opening through which the light emitted from the light emitting element passes.
A lid that can be opened and closed, the opening opens when opened, and the opening closes when closed.
A drive mechanism that opens and closes the lid,
Including atomic oscillators. In claim 1,
The material of the lid is the same as the material of the container, an atomic oscillator. In claim 1 or 2,
An atomic oscillator comprising an elastic member located between the lid and the container when the lid is closed. In any one of claims 1 to 3,
A control circuit for controlling the drive mechanism is included.
The control circuit is an atomic oscillator that causes the drive mechanism to open the lid after a lapse of a predetermined time from the heater starting heating of the atomic cell. In claim 4,
The control circuit is an atomic oscillator that causes the drive mechanism to close the lid when the heater stops heating the atomic cell. In any one of claims 1 to 3,
A control circuit that controls the drive mechanism and
A temperature sensor that detects the temperature inside the container and
Including
The control circuit is based on the detection result of the temperature sensor.
When the temperature inside the container is lower than the predetermined temperature, the drive mechanism is made to close the lid.
An atomic oscillator that causes the drive mechanism to open the lid when the temperature inside the container is equal to or higher than the predetermined temperature. In any one of claims 1 to 6,
An atomic oscillator that closes the lid of the drive mechanism when the energization of the drive mechanism is stopped. A frequency signal generation system that includes an atomic oscillator
The atomic oscillator
Light emitting element and
An atomic cell containing an alkali metal atom, which is irradiated with the light emitted from the light emitting element, and
A heater that heats the atomic cell and
A container containing the atomic cell and the heater and having an opening through which the light emitted from the light emitting element passes.
A lid that can be opened and closed, the opening opens when opened, and the opening closes when closed.
A drive mechanism that opens and closes the lid,
Frequency signal generation system, including.

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