Atomic beam generator, physics package, physics package for optical lattice clock, physics package for atomic clock, physics package for atomic interferometer, physics package for quantum information processing device, and physics package system

Abstract

An atomic oven (40) includes a cartridge (200) and a main body (220). The cartridge (200) includes: a holder (202) that accommodates an atom source; and a capillary nozzle (204). The main body (220) includes: a housing (226) in which the cartridge (200) is installed; a button heater (228); an access opening (222a) for removing the cartridge (200) from the main body (220) and placing the cartridge into the main body (220), the access opening (222a) being provided on the atmosphere side, which is outside the main body (220); and a passage from the access opening (222a) to the housing (226). The cartridge (200) is inserted into the main body (220) through the access opening (222a) and is installed in the housing (226). The atom source is heated by the button heater (228), whereby atomic gas generated from the atom source is emitted as an atom beam to the vacuum side, which is outside the main body (220).

Description

[Technical Field]

[0001] The present invention relates to an atomic beam generating device, a physics package, a physics package for an optical lattice clock, a physics package for an atomic clock, a physics package for an atomic interferometer, a physics package for a quantum information processing device, and a physics package system. [Background technology]

[0002] Optical lattice clocks are atomic clocks proposed in 2001 by Hidetoshi Katori, one of the inventors of this application. Optical lattice clocks confine an atomic population within an optical lattice formed by laser light to measure resonant frequencies in the visible light region, enabling measurements with 18-digit precision, far exceeding the precision of current cesium clocks. Optical lattice clocks have been intensively researched and developed by the inventor's group, as well as by various other groups both in Japan and abroad, and are being developed as next-generation atomic clocks.

[0003] Recent optical lattice clock technologies can be found, for example, in the following Patent Documents 1 to 3. Patent Document 1 describes the formation of a one-dimensional moving optical lattice inside an optical waveguide having a hollow passage. Patent Document 2 describes a mode for setting an effective magic frequency. Furthermore, Patent Document 3 describes a radiation shield that reduces the influence of blackbody radiation emitted from surrounding walls.

[0004] Optical lattice clocks measure time with such high precision that a 1 cm difference in altitude on Earth, due to the general relativistic effect of gravity, can be detected as a deviation in the passage of time. Therefore, if optical lattice clocks could be made smaller and more portable for use in the field outside of laboratories, they could be applied to new geodesic technologies, such as underground resource exploration, detection of underground cavities, and magma chambers. By mass-producing optical lattice clocks and deploying them in various locations to continuously monitor temporal variations in gravitational potential, applications such as the detection of crustal movements and spatial mapping of gravitational fields could also be realized. In this way, optical lattice clocks are expected to contribute to society as a new fundamental technology that goes beyond the scope of high-precision time measurement.

[0005] Atomic ovens are known as devices for generating atomic beams for optical lattice clocks. Generally, atomic ovens are designed so that the emitted atoms have a small aperture angle, travel as straight as possible, and a sufficient number of atoms have the desired velocity distribution.

[0006] Generally, there is a limit to the number of atomic sources that can be installed in an atomic oven. If the number is too large, the size of the atomic oven increases, and the volume of the atomic oven that the heater must heat increases, resulting in excessive heater power consumption. As a result, this goes against the miniaturization and power saving of atomic ovens.

[0007] The ease of filling and refilling the atomic oven with atomic sources is beneficial not only when starting the optical lattice clock, but also during maintenance, such as when the atomic sources run out.

[0008] Non-Patent Document 1 describes an atomic oven that allows the atom source to be refilled. This atomic oven includes an ICF70 flange for attaching the atomic oven to the atomic clock body, and an ICF34 flange that has a nickel gasket and allows access to the sample chamber. This ICF34 flange is a flange that allows the atom source to be replaced or refilled. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Patent No. 6206973 [Patent Document 2] Special Publication No. 2018-510494 [Patent Document 3] Japanese Patent Application Publication No. 2019-129166 [Non-patent literature]

[0010] [Non-Patent Document 1] M.Schioppo et.al. REVIEW OF SCIENTIFIC INSTRUMENTS 83, 103101(2012) Summary of the Invention [Problem to be solved by the invention]

[0011] Now, consider the need to refill the atomic source after the atomic clock has been operating, for example, during maintenance. In the atomic oven described in Non-Patent Document 1, the ICF34 flange is located on the vacuum side of the atomic oven due to its structure, making it impossible to access the ICF34 flange directly from the atmosphere side. Therefore, to refill the atomic source, the ICF70 flange must be removed, the atomic oven must be detached from the atomic clock, and some components of the vacuum vessel must be disassembled before accessing the ICF34 flange and refilling the atomic source. Thus, in the prior art, the interior of the vacuum vessel of the atomic oven must be disassembled, making the process of replacing or refilling the atomic source cumbersome.

[0012] An object of the present invention is to provide an atomic beam generating apparatus in which the atom source can be replaced or refilled by simple operations without dismantling the vacuum side components. [Means for solving the problem]

[0013] One aspect of the present invention is an atomic beam generating device comprising: a cartridge including a holder for accommodating an atomic source; and a main body in which the cartridge is installed, wherein the main body comprises an installation section in which the cartridge is installed; a temperature adjustment mechanism for adjusting the temperature of the atomic source housed in the cartridge installed in the installation section; an access port provided on the atmospheric side outside the main body for inserting and removing the cartridge into and from the main body; and a passage leading from the access port to the installation section, wherein the temperature of the atomic source is adjusted by the temperature adjustment mechanism, so that atomic gas generated from the atomic source is emitted from the main body as an atomic beam to the vacuum side outside the main body.

[0014] According to the above configuration, the cartridge can be inserted into and removed from the installation section of the main body of the atomic beam generating device through the access port on the atmosphere side. For example, the atom source can be replaced by removing a cartridge containing a used atom source from the access port to the atmosphere side outside the main body, and inserting another cartridge containing an atom source into the main body through the access port and installing it in the installation section. This simple procedure makes it possible to replace or refill the atom source.

[0015] The atomic beam generating device may further include an elastic mechanism that pushes the cartridge placed on the placement section from the side of the loading / unloading opening toward the placement section. By pushing the cartridge toward the placement section with the elastic mechanism, the cartridge can be stably placed on the placement section.

[0016] The elastic mechanism may push the cartridge toward the installation portion by the elastic force of a spring. The spring may be, for example, a coil spring. Of course, a spring other than a coil spring may be used, or an elastic member other than a spring may be used.

[0017] The outer surface of the holder may have a tapered shape toward the tip of the holder, and the surface of the installation part on which the cartridge is installed may have a tapered shape corresponding to the shape of the outer peripheral surface of the holder. By forming the outer peripheral surface of the holder and the surface of the installation part into a tapered shape, these surfaces can be easily processed and the cartridge can be stably installed in the installation part.

[0018] A thread groove may be formed on the surface of the installation part on which the cartridge is installed, and a thread groove that meshes with the thread groove of the installation part may be formed on the outer surface of the holder. By meshing the thread groove on the outer peripheral surface of the holder with the thread groove on the installation part, it becomes possible to stably install the cartridge on the installation part.

[0019] The cartridge may further include a nozzle integrated with the holder, and the atomic gas generated from the atom source may be emitted to the vacuum side through the nozzle.

[0020] The temperature adjustment mechanism may be installed around the tip of the nozzle. With this configuration, a temperature gradient is formed between the tip of the nozzle and the sample chamber inside the holder. For example, if the temperature adjustment mechanism is a heater, the temperature of the tip of the nozzle will be higher than the temperature inside the sample chamber. This makes it possible to suppress or prevent the atomic gas generated from the atom source from being adsorbed onto the tip of the nozzle by the heating of the heater.

[0021] The atom source may be an atom source that generates an atomic gas when heated, the temperature adjustment mechanism may be a heater that heats the atom source, and the nozzle may be sealed with a sealant that evaporates when heated by the heater. With this configuration, the inside of the holder is not exposed to the atmosphere until the sealant evaporates, making it possible to suppress or prevent oxidation or deterioration of the atom source housed in the holder. For example, strontium or ytterbium is used as the atom source. For example, indium is used as the sealant.

[0022] The atom source may be an atom source that generates an atomic gas by being cooled, and the temperature adjustment mechanism may be a cooling mechanism that cools the atom source. For example, mercury or the like is used as the atom source.

[0023] One aspect of the present invention is a physics package comprising the above-described atomic beam generating device and a vacuum chamber surrounding a clock transition space in which atoms are placed.

[0024] One aspect of the present invention is a physics package for an optical lattice clock, comprising the above-described physics package.

[0025] One aspect of the present invention is a physics package for an atomic clock, comprising the above-described physics package.

[0026] One aspect of the present invention is a physics package for an atom interferometer, comprising the above-described physics package.

[0027] One aspect of the present invention is a physics package for a quantum information processing device for atoms or ionized atoms, characterized by including the above-mentioned physics package.

[0028] One aspect of the present invention is a physics package system including the above-described physics package. [Effects of the Invention]

[0029] According to the present invention, it is possible to provide an atomic beam generating apparatus in which the atom source can be replaced or filled with a simple operation without disassembling the vacuum side components. [Brief explanation of the drawings]

[0030] [Figure 1] FIG. 1 is a block diagram showing the overall configuration of an optical lattice clock according to an embodiment of the present invention. [Figure 2] FIG. 1 is a diagram schematically illustrating a physics package of an optical lattice clock according to an embodiment of the present invention. [Figure 3] 1 is a cross-sectional view of an atomic oven according to a first embodiment. [Figure 4] 1 is a cross-sectional view of an atomic oven according to a first embodiment. [Figure 5] FIG. 1 is an exploded perspective view of an atomic oven according to a first embodiment. [Figure 6] FIG. 10 is a cross-sectional view of an atomic oven according to a second embodiment. [Figure 7] FIG. 10 is a cross-sectional view of an atomic oven according to a second embodiment. [Figure 8] FIG. 10 is a cross-sectional view of the atomic beam generating device according to the third embodiment. [Figure 9] FIG. 10 is a cross-sectional view of the atomic beam generating device according to the third embodiment. [Figure 10] FIG. DETAILED DESCRIPTION OF THE INVENTION

[0031] <Configuration of an optical lattice clock> The schematic configuration of an optical lattice clock 10 in which the atomic beam generating device according to this embodiment is used will be described with reference to Fig. 1. Fig. 1 is a block diagram showing the overall configuration of the optical lattice clock 10. Here, the optical lattice clock 10 will be used as an example of a device in which the atomic beam generating device is used, but of course the atomic beam generating device according to this embodiment may also be used in devices other than the optical lattice clock 10.

[0032] The optical lattice clock 10 includes, for example, a physics package 12, an optical system 14, a control system 16, and a PC (Personal Computer) 18.

[0033] The physics package 12 is a device that captures an atomic ensemble, confines it in an optical lattice, and causes a clock transition. The optical system 14 is a device equipped with optical devices such as a laser light source for atom capture, a clock transition excitation laser light source, and a laser frequency control device. In addition to sending laser light to the physics package 12, the optical system 14 receives fluorescent signals emitted by the atomic ensemble in the physics package 12, converts them into electrical signals, and feeds them back to the laser light source to match the atomic resonance frequency. The control device 16 is a device that controls the physics package 12 and the optical system 14. The control device 16 controls, for example, the operation of the physics package 12 and the optical system 14, and performs analytical processing such as frequency analysis of clock transitions obtained by measurements. The functions of the optical lattice clock 10 are realized by the mutual cooperation of the physics package 12, the optical system 14, and the control device 16.

[0034] The PC 18 is a general-purpose computer including a processor and memory. The functions of the PC 18 are realized by software being executed by hardware including the processor and memory. An application program that controls the optical lattice clock 10 is installed in the PC 18. The PC 18 is connected to the control device 16 and may control not only the control device 16 but also the entire optical lattice clock 10 including the physics package 12 and the optical device 14. The PC 18 also provides a UI (User Interface) for the optical lattice clock 10. A user can start the optical lattice clock 10, measure time, and check results via the PC 18.

[0035] A system including physics package 12 and the configuration required to control physics package 12 may be referred to as a "physics package system." The configuration required for control may be included in control device 16 or PC 18, or may be included in physics package 12. In addition, some or all of the functions of control device 16 may be included in physics package 12.

[0036] The physics package 12 will be described below with reference to Fig. 2. Fig. 2 is a diagram showing a schematic diagram of the physics package 12 of the optical lattice clock according to the embodiment.

[0037] The physics package 12 includes a vacuum chamber 20, an atomic oven 40, a Zeeman decelerator coil 44, an optical resonator 46, a MOT (Magneto-Optical Trap) device coil 48, a cryostat 54, a thermal link member 56, a refrigerator 58, a vacuum pump main body 60, and a vacuum pump cartridge 62. The atomic oven 40 is an example of an atomic beam generating device.

[0038] The vacuum chamber 20 is a container that maintains a vacuum in the main portion of the physics package 12 and is formed in a generally cylindrical shape. Specifically, the vacuum chamber 20 includes a large, generally cylindrical main body 22 and a small, generally cylindrical protrusion 30 that protrudes from the main body 22. The main body 22 houses the optical resonator 46 and other components. The main body 22 includes a cylindrical wall 24 that forms the side surface of the cylinder, and a front circular wall 26 and a rear circular wall 28 that form the circular surfaces of the cylinder. The front circular wall 26 is a wall on which the protrusion 30 is provided. The rear circular wall 28 is the wall opposite the protrusion 30 and is formed with a larger diameter than the cylindrical wall 24.

[0039] The protrusion 30 includes a cylindrical wall 32 that forms the side surface of the cylinder, and a front circular wall 34. The front circular wall 34 is a circular surface on the side farther from the main body 22. The side of the protrusion 30 facing the main body 22 is mostly open and connected to the main body 22, and does not have a wall.

[0040] The vacuum chamber 20 is positioned so that the central axis of the cylinder of the main body 22 (this axis is called the Z-axis) is approximately horizontal. The central axis of the cylinder of the protrusion 30 (this axis is the beam axis) extends vertically below and parallel to the Z-axis.

[0041] The vacuum chamber 20 is made of a metal such as SUS (stainless steel) to be sufficiently robust so that it can withstand the pressure difference that occurs when a vacuum is created inside. The rear circular wall 28 and the front circular wall 34 of the vacuum chamber 20 are formed so that they can be removed for maintenance and inspection.

[0042] The atomic oven 40 is an example of an atomic beam generating device, and is provided near the tip of the protrusion 30 .

[0043] The atomic beam generating apparatus according to this embodiment includes a temperature adjustment mechanism that adjusts the temperature of the atom source, which is a sample. By adjusting the temperature of the atom source with the temperature adjustment mechanism, atomic gas is generated from the atom source, and the generated atomic gas is released from the aperture to form an atomic beam 42. The temperature adjustment mechanism is a heater, which is a heating mechanism that heats the atom source, or a cooling mechanism (e.g., a Peltier element) that cools the atom source. When an atom source that generates atomic gas by heating (e.g., strontium, ytterbium, etc.) is used, a heater is used as the temperature adjustment mechanism. When an atom source that generates atomic gas by cooling (e.g., mercury) is used, a cooling mechanism is used as the temperature adjustment mechanism. The atom sources exemplified here are merely examples, and the atom source is not limited to these.

[0044] In the example shown in FIG. 2, an atomic oven 40 is used as an example of the atomic beam generating device.

[0045] The atomic oven 40 heats the atom source with a heater and releases atoms that have been ejected from the atom source due to thermal motion through a fine hole, thereby forming an atomic beam 42. The beam axis along which the atomic beam 42 travels is set parallel to the Z axis and is set to intersect with the X axis at a position slightly away from the origin. The position of intersection corresponds to a trapping space 50, which is a tiny space in which atoms are trapped. The atomic oven 40 is basically installed inside the vacuum chamber 20, but a heat sink extends outside the vacuum chamber 20 for cooling purposes. In the atomic oven 40, the atom source is heated to, for example, about 750 K.

[0046] In this embodiment, the atomic oven 40 includes a cartridge 200 including a holder for accommodating an atomic source, and a main body in which the cartridge 200 is installed. The cartridge 200 is a unit that can be attached to and detached from the main body. By removing the cartridge 200 from the main body of the atomic oven 40, it is possible to replace or refill the atom source. The cartridge 200 will be described in detail later.

[0047] The Zeeman decelerator coil 44 is located downstream of the beam axis of the atomic oven 40, extending from the protrusion 30 of the vacuum chamber 20 to the main body 22. The Zeeman decelerator coil 44 is a device that combines a Zeeman decelerator, which decelerates the atoms in the atomic beam 42, with an MOT device, which captures the decelerated atoms. Both the Zeeman decelerator and the MOT device are based on atomic laser cooling technology. The Zeeman decelerator coil 44 is a series of coils that includes a Zeeman coil used in the Zeeman decelerator and one of a pair of MOT coils used in the MOT device. Although a clear division is not possible, roughly speaking, the majority of the coils from the upstream to downstream sides correspond to the Zeeman coil, which generates the magnetic field that contributes to the Zeeman deceleration method, and the most downstream side corresponds to the MOT coil, which generates the gradient magnetic field that contributes to the MOT method.

[0048] For example, the Zeeman coil is a decelerating type with more turns on the upstream side and fewer turns on the downstream side. The Zeeman decelerator coils 44 are arranged axially symmetrically around the beam axis so that the atomic beam 42 passes inside the Zeeman coil and the MOT coil. A spatially gradient magnetic field is formed inside the Zeeman coil, and the atoms are decelerated by irradiating it with a Zeeman deceleration light beam 82.

[0049] The optical resonator 46 is a cylindrical component arranged around the Z axis, and an optical lattice is formed inside it. The optical resonator 46 is equipped with multiple optical components. It includes a pair of optical mirrors on the X axis and another pair of optical mirrors parallel to them. A bowtie-shaped optical lattice resonator is created by multiple reflection of the optical lattice light between a total of four mirrors. The atomic ensemble trapped in the trapping space 50 is confined inside this optical lattice. Furthermore, in the optical resonator 46, when the relative frequencies of the two optical lattice beams (clockwise and counterclockwise) incident on the resonator are shifted, a moving optical lattice is formed, in which the standing wave of the optical lattice moves. The moving optical lattice moves the atomic ensemble to the clock transition space 52. In this embodiment, an optical lattice including a moving optical lattice is formed on the X axis. It is also possible to use a two-dimensional or three-dimensional optical lattice in which lattices are arranged on one or both of the Y axis and the Z axis in addition to the X axis. In this way, the optical resonator 46 can be considered an optical lattice forming unit that forms an optical lattice. The optical resonator 46 is also a device based on the atomic laser cooling technology.

[0050] The MOT device coil 48 generates a gradient magnetic field for the trapping space 50. In the MOT device, MOT light is irradiated along three axes, X, Y, and Z, into the space in which the gradient magnetic field is formed. This allows the MOT device to trap atoms in the trapping space 50. The trapping space 50 is set on the X axis. The Zeeman decelerator coil 44 is provided as a series of coils, including a Zeeman coil used in the Zeeman decelerator and one of a pair of MOT coils used in the MOT device. In the example shown in FIG. 2, the gradient magnetic field contributing to the MOT method is generated by the MOT device coil 48 together with a portion of the Zeeman decelerator coil 44.

[0051] The cryostat 54 is formed to surround the clock transition space 52 and keeps the internal space at a low temperature. This reduces blackbody radiation in the internal space. A thermal link member 56, which also serves as a support structure, is attached to the cryostat 54. The thermal link member 56 conducts heat from the cryostat 54 to a refrigerator 58. The refrigerator 58 is a device that cools the cryostat 54 via the thermal link member 56. The refrigerator 58 is equipped with a Peltier element and cools the cryostat 54 to, for example, about 190K.

[0052] The vacuum pump main body 60 and the vacuum pump cartridge 62 are devices for evacuating the vacuum chamber 20. The vacuum pump main body 60 is provided outside the vacuum chamber 20, and the vacuum pump cartridge 62 is provided inside the vacuum chamber 20. When the vacuum pump cartridge 62 starts up, it is heated and activated by a heater provided in the vacuum pump main body 60. This activates the vacuum pump cartridge 62, which then adsorbs atoms to create a vacuum.

[0053] The physics package 12 is provided with vacuum-resistant optical windows 64, 66 for optical lattice light, a vacuum-resistant optical window 68 for MOT light, vacuum-resistant optical windows 70, 72 for Zeeman-decelerated light and MOT light, and optical mirrors 74, 76 as optical system components.

[0054] Vacuum-resistant optical windows 64 and 66 for optical lattice light are provided for the input and output of optical lattice light.

[0055] The vacuum-resistant optical window 68 for MOT light is provided for the entrance and exit of two axes of MOT light among the three axes of MOT light used in the MOT device.

[0056] The vacuum-resistant optical windows 70 and 72 for Zeeman-moderated light and MOT light are provided for the input and output of Zeeman-moderated light and uniaxial MOT light.

[0057] Optical mirrors 74 and 76 are provided to redirect the Zeeman decelerated light and the uniaxial MOT light.

[0058] The physics package 12 also includes cooling components such as an atomic oven cooler 90, a Zeeman decelerator cooler 92, and an MOT device cooler 94.

[0059] The atomic oven cooler 90 is a water-cooling device that cools the atomic oven 40. The atomic oven cooler 90 is provided outside the vacuum chamber 20 and cools the heat dissipation part of the atomic oven 40 that extends outside the vacuum chamber 20. The atomic oven cooler 90 is equipped with a metal water-cooled pipe that is a cooling pipe, and cools the vacuum chamber 20 by flowing cooling water, which is a liquid refrigerant, inside the pipe.

[0060] The Zeeman decelerator cooler 92 is provided on the wall of the vacuum chamber 20 and is a device for cooling the Zeeman decelerator coil 44. The Zeeman decelerator cooler 92 has a metal pipe and removes Joule heat generated in the coil of the Zeeman decelerator coil 44 by flowing cooling water inside.

[0061] The MOT device cooler 94 is a heat dissipation unit provided in the circular wall of the vacuum chamber 20. The MOT device coil 48 generates Joule heat in the coil, although it is smaller (for example, about 1 / 10) than the Zeeman decelerator cooler 92. Therefore, the metal of the MOT device cooler 94 extends from the MOT device coil 48 to the outside of the vacuum chamber 20 and releases heat into the atmosphere.

[0062] The physics package 12 also includes components for correcting the magnetic field, such as a three-axis magnetic field compensation coil 96, a vacuum-resistant electrical connector 98, an individual magnetic field compensation coil 102 for the refrigerator, and an individual magnetic field compensation coil 104 for the atomic oven.

[0063] The three-axis magnetic field correction coil 96 is a coil for uniformly zeroing the magnetic field in the clock transition space 52. The three-axis magnetic field correction coil 96 is formed in a three-dimensional shape so as to correct the magnetic fields in the three axial directions of X, Y, and Z. For example, the three-axis magnetic field correction coil 96 is formed in a substantially cylindrical shape as a whole. Each coil constituting the three-axis magnetic field correction coil 96 is formed in a point-symmetric shape in each axial direction with the clock transition space 52 as the center.

[0064] The vacuum-resistant electrical connector 98 is a connector for supplying power into the vacuum chamber 20, and is provided on the circular wall of the vacuum chamber 20. Power is supplied from the vacuum-resistant electrical connector 98 to the Zeeman decelerator coil 44, the MOT device coil 48, and the three-axis magnetic field correction coil 96.

[0065] The refrigerator individual magnetic field compensation coil 102 is a coil for compensating for the leakage magnetic field from the refrigerator 58 that cools the cryostat 54. The Peltier element included in the refrigerator 58 is a large-current device through which a relatively large current flows, generating a large magnetic field. The Peltier element is surrounded by a high-permeability material to shield the magnetic field, but this is not complete, and some of the magnetic field leaks. Therefore, the refrigerator individual magnetic field compensation coil 102 is configured to compensate for this leakage magnetic field in the clock transition space 52.

[0066] The atomic oven individual magnetic field compensation coil 104 is a coil for compensating for the leakage magnetic field from the heater of the atomic oven 40. The heater of the atomic oven 40 is also a high-current device, and the leakage magnetic field may not be negligible despite shielding with a high-permeability material. For example, even if the heater circuit is constructed with non-inductive winding wiring, inductive components may actually remain in the wiring terminals or wiring through an insulating layer. Furthermore, even if the atomic oven 40 is magnetically shielded by covering it with a high-permeability material, there may be parts that cannot actually be covered, such as the atomic beam opening. Therefore, the atomic oven individual magnetic field compensation coil 104 is configured to compensate for this leakage magnetic field in the clock transition space 52.

[0067] The operation of the physics package 12 will be described below. In the physics package 12, the vacuum pump cartridge 62 provided inside the vacuum chamber 20 adsorbs atoms, thereby creating a vacuum inside the vacuum chamber 20. As a result, the inside of the vacuum chamber 20 becomes a vacuum, for example, -8 A vacuum state of about Pa is created, eliminating the effects of air components such as nitrogen and oxygen.

[0068] In the atomic oven 40, an atomic source is heated by a heater to generate an atomic gas, which then passes through the apertures, where it is focused and translated. This forms an atomic beam 42. The atomic oven 40 is installed so that the atomic beam 42 is formed on a beam axis parallel to the Z axis. Note that, while the body of the atomic oven 40 is heated by the heater, the body of the atomic oven 40 and the joints supporting it are thermally insulated via thermal insulators. Furthermore, the joints connected to the physics package 12 are cooled by an atomic oven cooler 90, preventing or reducing the effects of high temperatures on the physics package 12.

[0069] When an atomic source (e.g., mercury) that generates atomic gas by being cooled is used, the atomic source is cooled by a cooling mechanism (e.g., a Peltier element) to generate atomic gas, which is then converged and translated to form an atomic beam 42.

[0070] The Zeeman decelerator coil 44 is installed symmetrically with respect to the beam axis. A Zeeman decelerated light beam 82 and a uniaxial MOT light beam 84 are irradiated into the Zeeman decelerator coil 44. The Zeeman decelerated light beam 82 enters through the vacuum-resistant optical window 70 for Zeeman decelerated light and MOT light and is reflected by an optical mirror 74 installed downstream of the MOT device coil 48. As a result, the Zeeman decelerated light beam 82 overlaps with the atomic beam 42 and travels upstream of the beam axis substantially parallel to the beam axis. During this process, due to the effects of Zeeman splitting proportional to the strength of the magnetic field and Doppler shift, the atoms in the atomic beam 42 absorb the Zeeman decelerated light and are given momentum in the deceleration direction, thereby decelerating. The Zeeman-moderated light is reflected by an optical mirror 76 placed on the side of the beam axis upstream of the Zeeman decelerator coil 44, and is emitted from the vacuum-resistant optical window 72 for Zeeman-moderated light and MOT light. Although Joule heat is generated in the Zeeman decelerator coil 44, it is prevented from becoming too hot by cooling it with the Zeeman decelerator cooler 92.

[0071] The sufficiently decelerated atomic beam 42 reaches the MOT device formed by the MOT coil located at the most downstream side of the Zeeman decelerator coil 44 and the MOT device coil 48. Within the MOT device, a magnetic field with a linear spatial gradient is formed around a trapping space 50. Furthermore, the MOT device is irradiated with MOT light from the positive and negative sides in three axial directions.

[0072] The MOT light beam 84 in the Z-axis direction is irradiated in the negative direction of the Z-axis, and is further irradiated in the positive direction of the Z-axis by being reflected outside the vacuum-resistant optical window 72 for Zeeman deceleration light and MOT light. The remaining two MOT light beams are irradiated into the MOT device by the vacuum-resistant optical window 68 for MOT light and an optical mirror (not shown).

[0073] In the MOT device, the atomic beam is decelerated by a restoring force caused by the magnetic field gradient around the trapping space 50. This causes the atomic group to be trapped in the trapping space 50. The position of the trapping space 50 can be fine-tuned by adjusting the offset value of the magnetic field generated by the three-axis magnetic field correction coil 96. Joule heat generated in the MOT device coil 48 is discharged to the outside of the vacuum chamber 20 by the MOT device cooler 94.

[0074] The optical lattice light beam 80 is incident on the X-axis from the vacuum-resistant optical window 64 for optical lattice light toward the vacuum-resistant optical window 66 for optical lattice light. An optical resonator 46 equipped with two optical mirrors is installed on the X-axis, causing reflection. Therefore, on the X-axis, an optical lattice potential is formed inside the optical resonator 46, with standing waves connected in the X-axis direction. The atomic ensemble is trapped by the optical lattice potential.

[0075] The optical lattice can be moved along the X-axis by slightly changing the wavelength. The atomic ensemble is moved to the clock transition space 52 by this moving optical lattice. As a result, the clock transition space 52 is moved away from the beam axis of the atomic beam 42, thereby eliminating the effects of blackbody radiation emitted by the high-temperature atomic oven 40. In addition, the clock transition space 52 is surrounded by a low-temperature chamber 54, which shields it from blackbody radiation emitted by the surrounding room-temperature materials. Generally, blackbody radiation is proportional to the fourth power of the absolute temperature of the material, so lowering the temperature by the low-temperature chamber 54 is highly effective in eliminating the effects of blackbody radiation.

[0076] In the clock transition space 52, atoms are irradiated with laser light with controlled optical frequency, and high-precision spectroscopy of the clock transition (i.e., the atomic resonance transition that serves as the clock reference) is performed to measure the atom's unique and invariant frequency. This results in an accurate atomic clock. To improve the accuracy of an atomic clock, it is necessary to eliminate perturbations surrounding the atom and accurately read out its frequency. Particularly important is the elimination of frequency shifts caused by the Doppler effect due to the atomic thermal motion. In an optical lattice clock, atoms are confined in an optical lattice created by the interference of laser light in a space sufficiently small compared to the wavelength of the clock laser, freezing the atomic motion. However, within the optical lattice, the laser light that forms the optical lattice causes the atomic frequency to shift. Therefore, a specific wavelength / frequency known as the "magic wavelength" or "magic frequency" is selected for the optical lattice light beam 80 to eliminate the influence of the optical lattice on the resonance frequency.

[0077] The clock transition is also affected by magnetic fields. Atoms in a magnetic field undergo Zeeman splitting according to the strength of the magnetic field, making it impossible to accurately measure the clock transition. Therefore, in the clock transition space 52, magnetic field correction is performed to homogenize and zero the magnetic field. First, the leakage magnetic field caused by the Peltier element of the refrigerator 58 is dynamically compensated for by the refrigerator's individual magnetic field compensation coil 102, which generates a compensation magnetic field according to the magnitude of the leakage magnetic field. Similarly, the leakage magnetic field caused by the heater of the atomic oven 40 is dynamically compensated for by the atomic oven's individual magnetic field compensation coil 104. Note that the current signals for the Zeeman decelerator coil 44 and the MOT device coil 48 are turned off when measuring the clock transition frequency, preventing the influence of the magnetic field. The magnetic field in the clock transition space 52 is further compensated for by the triaxial magnetic field correction coil 96. Multiple triaxial magnetic field correction coils 96 are installed in each axis direction, allowing for the removal of not only the uniform component of the magnetic field but also its spatially varying component.

[0078] In this way, the clock transition of the atomic ensemble is stimulated by the laser light in a state where disturbances are removed. The light emitted as a result of the clock transition is received by an optical system and subjected to spectral processing by a control device to determine the frequency.

[0079] The atomic beam generating device will be described in detail below.

[0080] <Atomic beam generating device according to embodiment 1> An atomic beam generating apparatus according to a first embodiment will be described with reference to Fig. 3 to Fig. 5. Fig. 3 to Fig. 5 show an atomic oven 40, which is an example of an atomic beam generating apparatus. Fig. 3 is a cross-sectional view of the atomic oven 40. Fig. 4 is a cross-sectional view of the atomic oven 40. Fig. 5 is an exploded perspective view of the atomic oven 40. Note that Fig. 5 shows only a part of the atomic oven 40 (for example, the cartridge 200 and the flange 222).

[0081] The atomic oven 40 includes a cartridge 200 and a body 220 in which the cartridge 200 is installed.

[0082] The cartridge 200 includes a holder 202 , a capillary nozzle 204 , and a cover 206 .

[0083] The holder 202 is, for example, a cylindrical member. A sample chamber 208, which is a space, is formed inside the holder 202, and an atom source serving as a sample is placed inside the sample chamber 208. In this manner, the atom source is housed within the holder 202. A screw groove 202a is formed on the outer surface of the holder 202. The screw groove 202a is a groove that meshes with a screw groove 226a formed on the inner circumferential surface of a housing 226, which will be described later. As will be described later, the screw groove 202a meshes with the screw groove 226a, thereby fixing the cartridge 200 to the housing 226.

[0084] The capillary nozzle 204 is a cylindrical member having a diameter smaller than that of the holder 202. The capillary nozzle 204 is provided at one end of the holder 202 and extends from that end. For example, the holder 202 and the capillary nozzle 204 are an integrated member. The sample chamber 208 and the capillary nozzle 204 are in communication with each other, and the atomic gas generated from the atom source in the sample chamber 208 passes through the capillary nozzle 204 and is emitted to the outside of the atomic oven 40 as an atomic beam 42.

[0085] The cover 206 is a member that is detachably attached to the other end of the holder 202 with screws. By removing the cover 206 from the holder 202, the sample chamber 208 is opened and the atom source can be installed in the sample chamber 208.

[0086] As the atom source, for example, an atom source that generates an atomic gas by heating, such as strontium or ytterbium, is used, although of course, other atom sources may also be used.

[0087] A groove 212 is formed on the surface of the cover 206. The groove 212 has a shape that allows a flat-head screwdriver to be inserted, for example. Specifically, the groove 212 is a linear groove or a cross-shaped groove (for example, a groove where two linear grooves intersect).

[0088] The main body 220 includes a flange 222, a heat radiation shield 224, a housing 226, a button heater 228, a cover 230, a thermal insulating tube 232, a rod 234, a heat radiation shield 236, and a temperature sensor that measures the temperature of the sample chamber 208 in the holder 202. These components are located in the vacuum portion (vacuum side) of the physics package 12.

[0089] The flange 222 is a vacuum flange (e.g., an ICF70 flange) for attaching the atomic oven 40 to the physics package 12. One side of the flange 222 is the vacuum side, and the other side is the atmosphere side. In other words, when the flange 222 is attached to the physics package 12, the above-mentioned components (such as the thermal radiation shield 224) are located on the vacuum side.

[0090] The flange 222 is formed with an access port 222a, which is a hole that penetrates the flange 222 in the thickness direction. The access port 222a is a hole for inserting and removing the cartridge 200 into and from the main body 220 from the atmospheric side, which is the outside of the flange 222, and has a diameter larger than that of the holder 202.

[0091] Furthermore, a flow path 222b through which the coolant flows, and vacuum hermetic seal connectors 222c and 222d that can electrically connect the vacuum side and the atmosphere side are appropriately provided on the flange 222. Connector 222c is a connector for a button heater 228, and one end of a lead wire for the button heater 228 is connected to connector 222c. The other end of the lead wire is connected to button heater 228. Connector 222d is a connector that is connected to a temperature sensor.

[0092] With the position of the flange 222 as a reference, a heat radiation shield 224, a housing 226, and a button heater 228 are arranged in this order from the flange 222 side.

[0093] The thermal radiation shield 224 has, for example, a cylindrical shape and is attached to the flange 222. The thermal radiation shield 224 is a member made of, for example, SUS (stainless steel). The thermal radiation shield 224 is attached to the flange 222 in accordance with the position of the loading / unloading opening 222a of the flange 222. A passage 238, which is a space, is formed inside the cylindrical thermal radiation shield 224. The passage 238 is a space through which the cartridge 200 inserted into the main body 220 from the loading / unloading opening 222a passes. The passage 238 has a shape corresponding to the outer shape of the holder 202, and the size (e.g., diameter) of the passage 238 is slightly larger than the size (e.g., diameter) of the holder 202. Thus, the passage 238 has a shape and size that allow the holder 202 to be inserted therein. The cartridge 200 is inserted into the housing 226 through the passage 238 and supported by the housing 226.

[0094] The housing 226 is a member that supports the cartridge 200 on one side (the side facing the heat radiation shield 224) and the button heater 228 on the other side (the side opposite the heat radiation shield 224). The housing 226 corresponds to an example of an installation portion. The housing 226 is a member made of, for example, SUS. One side of the housing 226 has a shape (for example, a cylindrical shape) that corresponds to the shape of the holder 202 of the cartridge 200, and part or all of the holder 202 is installed in the portion having that shape. In the example shown in FIG. 4, part of the holder 202 is installed on one side of the housing 226 and supported by the housing 226.

[0095] A screw groove 226a is formed on the inner surface of one side of the housing 226. The screw groove 226a has a shape that meshes with the screw groove 202a formed on the outer peripheral surface of the holder 202.

[0096] A hole 226b is formed in the bottom of the housing 226, penetrating the bottom from one side to the other. The capillary nozzle 204 of the cartridge 200 is inserted into the hole 226b and penetrates the bottom of the housing 226.

[0097] The button heater 228 is an example of a temperature adjustment mechanism, and is a heating mechanism that heats the sample chamber 208 in the holder 202. In the example shown in FIG. 4, the button heater 228 is arranged around the tip of the capillary nozzle 204 so as not to cover the opening at the tip of the capillary nozzle 204. This makes the temperature at the tip of the capillary nozzle 204 higher than the temperature in the sample chamber 208. In this way, the installation position of the button heater 228 is determined so that a temperature gradient is formed from the capillary nozzle 204 to the sample chamber 208.

[0098] A cover 230 is provided to cover the button heater 228. A hole 230a is formed in the cover 230 at a position corresponding to the position of the hole 226b in the housing 226. The tip of the capillary nozzle 204 is inserted into the hole 230a.

[0099] A thermal insulating tube 232 and a rod 234 are installed outside the thermal radiation shield 224 and the housing 226, extending from the installation position of the button heater 228 to the flange 222. One ends of the thermal insulating tube 232 and the rod 234 are connected (e.g., fixed) to the cover 230 of the button heater 228, and the other ends of the thermal insulating tube 232 and the rod 234 are connected (e.g., fixed) to the flange 222. The thermal insulating tube 232 has a cylindrical shape, and the rod 234 is installed inside the thermal insulating tube 232. The thermal insulating tube 232 is made of, for example, magnesium oxide, and the rod 234 is made of, for example, a steel member. The thermal insulating tube 232 and the rod 234 mechanically support the heated portion (e.g., the button heater 228 and the cover 230) and prevent heat from the heated portion from escaping to the outside.

[0100] The thermal radiation shield 236 is a member that covers the thermal radiation shield 224, the housing 226, the button heater 228, the cover 230, the thermal insulating tube 232, and the rod 234. The thermal radiation shield 236 is a member made of, for example, aluminum. A hole 236a is formed in the bottom of the thermal radiation shield 236, penetrating the bottom at a position corresponding to the hole 226b in the housing 226 and the hole 230a in the cover 230, that is, at a position corresponding to the tip of the capillary nozzle 204 of the cartridge 200 installed in the housing 226.

[0101] Furthermore, a flange 240 (e.g., an ICF34 flange) is installed on the atmosphere side of the flange 222 (i.e., the side opposite to the vacuum side where the thermal radiation shield 224 and the like are installed). The flange 240 is attached to the atmosphere side of the flange 222 so as to cover the loading / unloading opening 222a of the flange 222. By attaching the flange 240 to the flange 222, the loading / unloading opening 222a is closed.

[0102] A columnar rod 244 is fixed to one surface of the flange 240 (i.e., the surface facing the flange 222). A disc-shaped thermal radiation shield 242 is fixed to the tip of the rod 244. The diameter of the thermal radiation shield 242 is smaller than the diameter of the loading / unloading port 222a and the diameter of the passage 238. The thermal radiation shield 242 and the rod 244 are members made of, for example, SUS.

[0103] The procedure for installing the cartridge 200 in the main body 220 of the atomic oven 40 will now be described.

[0104] With the main body 220 of the atomic oven 40 attached to the physics package 12, the vacuum side of the atomic oven 40 is returned to the atmosphere, and the flange 240 is removed from the flange 222. This exposes the inside of the passage 238 to the atmosphere via the access port 222a.

[0105] Next, the cartridge 200, with the atom source accommodated in the sample chamber 208, is inserted into the passage 238 via the access port 222a and then inserted through the passage 238 into the housing 226. For example, a flat-head screwdriver is placed against the groove 212 of the cartridge 200, and the cartridge 200 is inserted into the housing 226 while rotating it using the flat-head screwdriver. This rotation causes the thread groove 202a formed on the outer peripheral surface of the holder 202 to engage with the thread groove 226a formed on the inner peripheral surface of the housing 226, thereby fixing the cartridge 200 to the housing 226 and supporting it therewith.

[0106] The capillary nozzle 204 of the cartridge 200 passes through the hole 226b of the housing 226 and is further inserted into the hole 230a of the cover 230 of the button heater 228. As a result, the tip of the capillary nozzle 204 is located at a position corresponding to the hole 236a of the thermal radiation shield 236.

[0107] Next, flange 240 is attached to flange 222. As a result, access opening 222a is closed by flange 240. By creating a vacuum inside physics package 12, passage 238 and sample chamber 208 are maintained at a vacuum.

[0108] An atomic gas is generated from the atom source housed in the sample chamber 208 by heating it with a button heater 228. The atomic gas passes through the capillary nozzle 204, is converged and translated, and is emitted from a hole 236a in the thermal radiation shield 236 to the vacuum side outside the atomic oven 40. This forms an atomic beam 42 (see FIG. 2).

[0109] Since the button heater 228 is provided around the tip of the capillary nozzle 204, the temperature of the tip of the capillary nozzle 204 becomes higher than the temperature inside the sample chamber 208. This makes it possible to suppress or prevent the atomic gas generated inside the sample chamber 208 from being adsorbed inside the capillary nozzle 204.

[0110] When removing the cartridge 200 from the main body 220 of the atomic oven 40, the vacuum part of the atomic oven 40 is returned to the atmosphere, and the flange 240 is removed from the flange 222. Next, a flathead screwdriver is inserted into the passage 238 from the loading / unloading port 222a, and the cartridge 200 is rotated by placing it against the groove 212 of the cartridge 200 and rotating it, and the cartridge 200 is then removed from the loading / unloading port 222a.

[0111] The above-described procedure makes it possible to replace the atomic source, etc. The cartridge 200 is a component independent of the components that make up the main body 220 of the atomic oven 40. Therefore, after attaching the main body 220 of the atomic oven 40 to the physics package 12, the cartridge 200 can be inserted into or removed from the main body 220 simply by removing the flange 240 provided on the atmosphere side. In other words, it is possible to replace the atomic source, etc., without removing the flange 222 from the physics package 12 and removing the main body 220 from the physics package 12. Because it is not necessary to remove the flange 222 from the physics package 12, the flange 222 can be fixed to the physics package 12 by welding, etc., which contributes to the miniaturization, cost reduction, and mass production of the atomic oven 40.

[0112] The heat insulating performance of the button heater 228 depends not only on the heat radiation shields' effectiveness in preventing heat outflow, but also on the thermal conductivity, diameter, and length of the thermal insulating tube 232 and rod 234 that connect the high-temperature side and the room-temperature side. For example, each component of the thermal insulating tube 232 and rod 234 is designed so that the portions that support the heating part are separated from the room-temperature side and are as long as possible.

[0113] The outer peripheral surface of the holder 202 and the inner peripheral surface of the housing 226 may be plated with a metal such as silver or molybdenum. For example, the screw grooves 202a, 226a are plated. This allows the cartridge 200 to be smoothly rotated and attached to or detached from the housing 226, even when the holder 202 and the housing 226 are heated by the button heater 228.

[0114] In the above-described first embodiment, the button heater 228 is used as the temperature adjustment mechanism, and an atom source (for example, strontium, ytterbium, etc.) that generates atomic gas by heating is used as the atom source. As another example, a cooling mechanism such as a Peltier element may be used as the temperature adjustment mechanism, and an atom source (for example, mercury, etc.) that generates atomic gas by cooling may be used as the atom source. In this case, too, the atom source can be replaced by the above-described procedure.

[0115] <Atomic beam generating device according to embodiment 2> An atomic beam generating apparatus according to a second embodiment will be described with reference to Fig. 6 and Fig. 7. Fig. 6 and Fig. 7 show an atomic oven 40A, which is an example of an atomic beam generating apparatus. Fig. 6 is a cross-sectional view of the atomic oven 40A. Fig. 7 is a cross-sectional view of the atomic oven 40A. In the second embodiment, the atomic oven 40A is installed in the physics package 12 instead of the atomic oven 40.

[0116] The atomic oven 40A includes a cartridge 260 and a body 220A in which the cartridge 260 is installed. In the second embodiment, the cartridge 260 is used instead of the cartridge 200 of the first embodiment, and the body 220A is used instead of the body 220 of the first embodiment.

[0117] The main body 220A includes a housing 250 instead of the housing 226 of the first embodiment. The main body 220A has the same configuration as the main body 220 of the first embodiment, except for the housing 250. The housing 250 has a hole 250b formed in the bottom thereof, similar to the hole 226b of the housing 226.

[0118] The cartridge 260 includes a holder 262 and a capillary nozzle 264 .

[0119] As in the first embodiment, a sample chamber 266 is formed as a space inside the holder 262, and an atom source is placed in the sample chamber 266 as a sample.

[0120] As in the first embodiment, a capillary nozzle 264 is provided at one end of the holder 262. In the second embodiment, a surface 262a, which is a part of the outer surface of the holder 262, is tapered toward the installation position of the capillary nozzle 264. Corresponding to the shape of the outer surface of the holder 262, an inner peripheral surface 250a of the housing 250 on which the holder 262 is installed is tapered. In consideration of machining accuracy, it is preferable that these surfaces be tapered, but of course, as in the first embodiment, the surface 262a of the holder 262 and the inner peripheral surface 250a of the housing 250 do not have to be tapered.

[0121] In the second embodiment, an elastic mechanism is used that pushes cartridge 260 placed in housing 250 from the loading / unloading opening 222a side toward housing 250. For example, the elastic mechanism uses a spring such as a coil spring to push cartridge 260 toward housing 250, and presses cartridge 260 against housing 250 to fix cartridge 260 to housing 250. The elastic mechanism will be described below.

[0122] The elastic mechanism is composed of, for example, a coil spring 270, a plunger 272, and a flange 278.

[0123] The plunger 272 includes a rod 272a and a disk portion 272b having a disk shape fixed to one end of the rod 272a. The disk portion 272b is a heat radiation shield and is a member that is pressed against the bottom surface 262b of the holder 262. A coil spring 270 is disposed at the other end of the rod 272a and is housed in a groove formed in a flange 278.

[0124] The following describes the procedure for installing the cartridge 260 in the main body 220A of the atomic oven 40A.

[0125] With the body 220A of the atomic oven 40A attached to the physics package 12, the vacuum side of the atomic oven 40A is vented to atmosphere and the flange 278 is removed from the flange 222.

[0126] Next, cartridge 260, in which a sample serving as an atom source is accommodated in sample chamber 266, is inserted into passage 238 via access port 222a. Furthermore, flange 278 is attached to flange 222 with coil spring 270 accommodated in the groove of flange 278 and the other end of rod 272a inserted into the groove. This causes disk portion 272b of plunger 272 to come into contact with bottom surface 262b of holder 262 of cartridge 260, and furthermore, the elastic force of coil spring 270 presses disk portion 272b against bottom surface 262b of holder 262. This elastic force presses cartridge 260 toward housing 250, and cartridge 260 is fixed to housing 250.

[0127] It should be noted that the coil spring 270 may have its natural length shortened if exposed to high temperatures, so it is preferable to mount it in a location where it is possible to maintain room temperature as much as possible.

[0128] The holder 262 is heated by the button heater 228, and the disk portion 272b of the plunger 272 comes into contact with the heated bottom surface 262b of the holder 262. In order to reduce the amount of heat flowing from the holder 262 to the plunger 272 as much as possible, it is preferable that the contact area between the disk portion 272b and the bottom surface 262b of the holder 262 is small. For example, the plunger 272 may be configured such that three protrusions are provided on the surface of the disk portion 272b that comes into contact with the bottom surface 262b, and these three protrusions come into contact with the bottom surface 262b. Reducing the number of contact points in this way reduces the contact area, and therefore the amount of heat flow from the holder 262 to the plunger 272.

[0129] In the second embodiment, similarly to the first embodiment, it is possible to detach flange 222 from physics package 12 and replace the atom source without removing main body 220A from physics package 12.

[0130] Alternatively, a cooling mechanism such as a Peltier element may be used as the temperature adjustment mechanism, and an atom source that generates atomic gas by cooling may be used as the atom source. In this case, too, the atom source can be replaced without removing main body 220A from physics package 12.

[0131] In the atomic ovens according to Examples 1 and 2 described above, the temperature distribution in the atomic oven was simulated when the steady state was reached after 9 W of power was applied to the button heater 228. As boundary conditions, cooling water piping was wrapped around the side of the flange 222, and the flange 222 was maintained at room temperature. Thanks to the function of the thermal insulating tube and each thermal radiation shield, a uniform high-temperature space with a small thermal gradient and the desired temperature was achieved in the housing and sample chamber.

[0132] We also simulated the displacement of the atomic oven when a force eight times the gravity at the Earth's surface was applied in a direction perpendicular to the longitudinal axis of the atomic oven (the Z-axis in Figure 2). If the displacement were large, the atomic beam would bend, potentially making it impossible to emit the atomic beam in the desired direction and position. The simulation results confirmed that even when the above force was applied in a direction perpendicular to the Z-axis, the strength of the thermal insulating tube 232, rod 234, etc. kept the displacement to less than 1 μm, posing no problems for the use of the atomic oven.

[0133] <Atomic beam generating device according to embodiment 3> An atomic beam generator according to a third embodiment will be described with reference to Fig. 8 and Fig. 9. Fig. 8 and Fig. 9 show an example of an atomic beam generator. Fig. 8 is a cross-sectional view of the atomic beam generator 40B. Fig. 9 is a cross-sectional view of the atomic beam generator 40B. In the third embodiment, the atomic beam generator 40B is installed in the physics package 12 instead of the atomic oven 40.

[0134] The atomic beam generating device 40B includes the same cartridge 200 as in the first embodiment and a main body 220B in which the cartridge 200 is installed.

[0135] The main body 220B includes a housing 226B instead of the housing 226 of the first embodiment. In the first embodiment, a button heater 228 is installed in the main body 220, but in the third embodiment, a cooling device 300 is installed in the main body 220 instead of the button heater 228. In addition, a thermal link member 302 extends from the housing 226B to the cooling device 300, and the housing 226B and the cooling device 300 are connected by the thermal link member 302. As a result, the housing 226B is cooled by the cooling device 300 via the thermal link member 302. The main body 220B has the same configuration as the main body 220 of the first embodiment, except for the housing 226B and the cooling device 300.

[0136] As in the first embodiment, a sample chamber 208, which is a space, is formed inside the holder 202 of the cartridge 200, and an atom source serving as a sample is placed in the sample chamber 208. In the third embodiment, for example, mercury atoms (e.g., liquid mercury) are placed in the sample chamber 208 as the atom source.

[0137] In the first embodiment, heat flows from the button heater 228 to the atom source via the housing 226 and the holder, thereby heating the atom source. In the third embodiment, heat is absorbed from the atom source by the cooling device 300 via the housing 226 and the thermal link member 302, thereby cooling the atom source.

[0138] For example, mercury atoms are less affected by blackbody radiation than the aforementioned strontium and ytterbium atoms, and are therefore considered promising for improving the precision of optical lattice clocks. Mercury has a low melting point of -40 degrees Celsius and is liquid at normal pressure and room temperature. Furthermore, even in a vacuum, its vapor pressure is relatively high at room temperature. Therefore, when using mercury as an atom source, it is preferable to cool and solidify the atom source to reduce its vapor pressure in order to reduce the atomic flow rate emitted from the atomic beam generator 40B to an appropriate amount under vacuum.

[0139] The atom source can be easily attached and detached, and the temperature of the atom source can be lowered during operation. Example 3 is suitable as an atomic beam generator for atoms that have a high vapor pressure at room temperature, such as mercury atoms.

[0140] One specific example of the cooling device 300 is a Peltier element. By passing an electric current through the junction of two or more metals that make up the Peltier element, heat flows from one junction surface to the other, resulting in the cooling of an object in contact with one surface. Specifically, by connecting the cooling surface of the Peltier element to the thermal link member 302 and the other surface to the flange 222, the atomic source can be cooled via the thermal link member 302 and the housing 226B. The electric current is supplied via a connector. Cooling water flows through the flow path 222b in the flange 222, allowing the heat generated by the Peltier element to be dissipated. The cooling capacity of the Peltier element is preferably high enough to cool the entire housing 226B via the thermal link member 302. Furthermore, even if the cooling of the capillary nozzle 204, which is far from the Peltier element, is somewhat insufficient, as long as the atom source close to the Peltier element can be cooled and the vapor pressure of the atom source can be appropriately controlled, wasteful consumption of the atom source can be suppressed, and there is no risk of the capillary nozzle 204 becoming clogged, so this does not pose a problem.

[0141] It is preferable that the thermal contact between the housing 226B and the holder 202 of the cartridge 200 be stronger when cooling the atom source than when heating it. This is because, while relatively large thermal conduction due to thermal radiation can be expected at high temperatures, thermal radiation cannot be expected at low temperatures, and thermal conduction via the contact surface becomes dominant. Therefore, for example, in the case of screw-type contact, a connection that increases the contact area, such as a fine-threaded screw, is preferable compared to a normal screw. Also, in the case of surface contact and contact using an elastic spring, as in Example 2, a strong connection is preferable, such as by making the surface roughness of the surface finer and by increasing the spring constant.

[0142] When using mercury as an atom source in the atomic beam generator 40B, one thing to be careful about is to use an appropriate amount of mercury in the liquid contained in the sample chamber 208 of the cartridge 200 so that the mercury does not block the capillary nozzle 204. Also, when attaching or detaching the cartridge 200 or storing the cartridge 200, care should be taken to maintain the orientation of the cartridge 200, such as handling it with the capillary nozzle 204 facing upward.

[0143] <How to manage cartridges 200 and 260> The following describes a method for managing the cartridges 200 and 260. As an example, a method for managing the cartridge 260 will be described below, but the cartridge 200 can also be managed using a similar method.

[0144] A method for managing the cartridge 260 will be described with reference to Fig. 10. Fig. 10 is a perspective view of the cartridge 260.

[0145] When strontium or the like is used as the atom source, the atom source oxidizes and deteriorates if exposed to the atmosphere for a long period of time. To prevent this, the atom source is filled into the sample chamber 266 in the holder 262 of the cartridge 260, the bottom lid of the holder 262 is closed, and the cartridge 260 is housed in a glass tube 280. A vacuum is drawn inside the glass tube 280. After the vacuum is drawn, the glass tube 280 may be purged with an inert gas. Note that instead of the glass tube 280, the cartridge 260 may be housed in a vacuum pack using a plastic bag or the like. In this way, the cartridge 260 itself, which houses the atom source, is stored in a vacuum or in an inert gas atmosphere.

[0146] It should be noted that cartridge 260 is not intended to be reused, but is intended to be disposable. The components that make up cartridge 260 are generally less expensive than the components that make up main body 220A. Permanently using main body 220A, which is made up of expensive, difficult-to-machine components, and replacing the consumable atom source with cartridge 260, which is an inexpensive component, is advantageous from the standpoints of product manufacturing and maintenance.

[0147] When cartridge 260 is to be used, once optical lattice clock 10 is ready, flange 278 is removed from flange 222, cartridge 260 is taken out of glass tube 280, cartridge 260 is loaded into main body 220A of atomic oven 40A, flange 278 is attached to flange 222, and evacuation of physics package 12 is initiated.

[0148] As described above, the cartridge 260 itself that houses the atom source is stored in a vacuum or in an inert gas atmosphere, so that oxidation of the atom source can be suppressed or prevented.

[0149] Furthermore, the capillary nozzle 264 may be sealed with a sealant 282 that evaporates when heated by the button heater 228. For example, the capillary nozzle 264 is sealed by filling the capillary nozzle 264 with the sealant 282.

[0150] For example, indium is used as the sealing material 282. Of course, materials other than indium may be used as the sealing material 282 as long as they are materials that evaporate when heated by the button heater 228.

[0151] By sealing the capillary nozzle 264 with the sealing material 282, the possibility that the sample chamber 266 in the holder 262 is exposed to the atmosphere is further reduced, and as a result, oxidation of the atom source can be suppressed or prevented.

[0152] When the optical lattice clock 10 is started, the button heater 228 is energized, and the sealing material 282 evaporates due to the heat generated by the button heater 228 , allowing the atomic gas generated from the atom source to pass through the capillary nozzle 264 .

[0153] In the above description, an optical lattice clock has been used as an example. However, those skilled in the art will recognize that the technology of this embodiment can be applied to devices other than optical lattice clocks. Specifically, the technology can also be applied to atomic clocks other than optical lattice clocks, or to atomic interferometers, which are interferometers using atoms. For example, a physics package for an atomic clock or a physics package for an atomic interferometer may be configured, including the atomic beam generator according to this embodiment and a vacuum chamber. This embodiment can also be applied to various quantum information processing devices for atoms or ionized atoms. A quantum information processing device is a device that performs measurement, sensing, and information processing using the quantum state of atoms or light. Examples of quantum information processing devices include atomic clocks and atomic interferometers, as well as magnetic field meters, electric field meters, quantum computers, quantum simulators, and quantum repeaters. By utilizing the technology of this embodiment, physics packages for quantum information processing devices can be made compact and portable, similar to physics packages for optical lattice clocks. Note that in such devices, the clock transition space may be treated simply as a space where clock transition spectroscopy occurs, rather than as a space intended for clock measurement.

[0154] In these devices, by using the atomic beam generating apparatus according to this embodiment, it becomes possible to replace the atomic source with a very simple operation without disassembling the inside of the vacuum vessel, and it also becomes possible to make these devices smaller and more portable.

[0155] In the above description, specific embodiments have been shown to facilitate understanding, but these are merely examples of embodiments, and various other embodiments are possible. [Explanation of symbols]

[0156] 10 Optical lattice clock, 12 Physics package, 40,40A Atomic oven, 200,260 Cartridge, 202,262 Holder, 204,264 Capillary nozzle, 208,266 Sample chamber, 220,220A Main body, 226,250 Housing, 228 Button heater, 270 Coil spring, 272 Plunger.

Claims

1. a cartridge including a holder for housing an atomic source; a main body in which the cartridge is installed; Including, The body includes: a mounting portion in which the cartridge is mounted; a temperature adjustment mechanism for adjusting the temperature of the atom source housed in the cartridge installed in the installation section; an insertion / removal opening provided on the atmosphere side outside the main body for inserting / removing the cartridge into / from the main body; a passageway leading from the loading / unloading opening to the installation section; Including, the temperature of the atom source is adjusted by the temperature adjustment mechanism, and the atomic gas generated from the atom source is emitted as an atomic beam from the main body to a vacuum side outside the main body. An atomic beam generating device characterized by:

2. 2. The atomic beam generating apparatus according to claim 1, further including an elastic mechanism that pushes the cartridge installed in the installation section from the side of the loading / unloading opening toward the side of the installation section, An atomic beam generating device characterized by:

3. 3. The atomic beam generating apparatus according to claim 2, the elastic mechanism pushes the cartridge toward the installation portion by the elastic force of a spring; An atomic beam generating device characterized by:

4. 4. The atomic beam generating apparatus according to claim 2, wherein: The outer surface of the holder has a tapered shape toward the tip of the holder, a surface of the installation portion on which the cartridge is installed has a tapered shape corresponding to the shape of the outer peripheral surface of the holder; An atomic beam generating device characterized by:

5. 2. The atomic beam generating apparatus according to claim 1, a thread groove is formed on a surface of the installation portion on which the cartridge is installed, A thread groove that engages with the thread groove of the installation portion is formed on the outer surface of the holder. An atomic beam generating device characterized by:

6. The atomic beam generating apparatus according to any one of claims 1 to 5, The cartridge further comprises: a nozzle integrated into the holder; The atomic gas generated from the atomic source passes through the nozzle and is emitted to a vacuum side. An atomic beam generating device characterized by:

7. 7. The atomic beam generating apparatus according to claim 6, The temperature adjustment mechanism is installed around the tip of the nozzle. An atomic beam generating device characterized by:

8. 8. The atomic beam generating apparatus according to claim 6 or 7, the atom source is an atom source that generates an atomic gas when heated, the temperature adjustment mechanism is a heater that heats the atom source, The nozzle is sealed with a sealant that evaporates when heated by the heater. An atomic beam generating device characterized by:

9. The atomic beam generating apparatus according to any one of claims 1 to 7, the atom source is an atom source that generates an atomic gas by being cooled, the temperature adjustment mechanism is a cooling mechanism that cools the atom source; An atomic beam generating device characterized by:

10. The atomic beam generating device according to any one of claims 1 to 9, a vacuum chamber surrounding a clock transition space in which atoms are placed; Including, A physics package characterized by:

11. 11. A physics package comprising: A physics package for optical lattice clocks.

12. 11. A physics package comprising: A physics package for an atomic clock, comprising:

13. 11. A physics package comprising: A physics package for an atom interferometer, comprising:

14. 11. A physics package comprising: A physics package for a quantum information processing device for atoms or ionized atoms, characterized in that:

15. 11. A physics package comprising: A physical packaging system.

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