JP6503697B2 - Gas cell manufacturing method and atomic oscillator - Google Patents

Description

  The present invention relates to a method of manufacturing a magnetic measurement device and a magnetic measurement device.

  There is known an optical pumping type magnetic measurement apparatus which irradiates linearly polarized light to a gas cell in which an alkali metal gas is sealed, and measures a magnetic field in accordance with the rotation angle of the polarization plane. In Patent Document 1, an ampoule in which an alkali metal is sealed is accommodated in a reservoir (ample storage chamber), and a laser beam is irradiated to the ampoule to form a through hole in the glass tube of the ampoule, and the alkali metal in the ampoule is removed. A magnetic measuring device is disclosed that includes a gas cell that is vaporized and fills the vapor (gas) from a reservoir into a main chamber through a communication hole.

JP, 2012-183290, A

  By the way, in the process of forming the through hole, the case where the processing in the depth direction is insufficient and the airtightness of the ampoule is not broken by the processing of forming one through hole by irradiating the laser light to one place alone or the through hole Although the amount of evaporation of the alkali metal in the ampoule is small, it may take a long time to fill the alkali metal gas in the main chamber. However, in order to reliably form the through holes and fill the main chamber with the alkali metal gas in a short time, if the process of irradiating the laser light to one place is repeated many times, the number of manufacturing steps is increased. There is a problem that you

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

  Application Example 1 A method of manufacturing a magnetic measurement device according to this application example is a method of manufacturing a magnetic measurement device that measures a magnetic field, and includes a first chamber, a second chamber, the first chamber, and the second chamber. A step of disposing an ampoule filled with an alkali metal material in the second chamber of the gas cell provided with a communicating hole communicating with the chamber, and sealing the first chamber, the second chamber and the communicating hole And a through hole forming step of forming a through hole in the ampoule by irradiating the ampoule with a laser beam, and the second chamber is provided with a predetermined position at which the ampoule settles, the through hole The forming step is characterized in that the laser light is irradiated to a plurality of places of the ampoule with reference to the predetermined position.

  According to the manufacturing method of this application example, in the through hole forming step, the laser light is irradiated to a plurality of locations of the ampoule arranged in the second chamber, so that the plurality of through holes can be formed in parallel in the ampoule. Therefore, as compared with the case where the laser light is irradiated to only one place, the probability of breaking the airtightness of the ampoule and forming the through holes is increased, and the area where the internal alkali metal material is exposed is enlarged, and The alkali metal gas can be filled in the first chamber from the two chambers via the communication hole. And a manufacturing man-hour can be reduced compared with the case where a process of irradiating a laser beam to one place is repeated, and a plurality of penetration holes are formed. In addition, since the laser beam is irradiated based on the predetermined position in a state where the ampoule is settled at the predetermined position, the position for irradiating the laser beam to the ampoule is more compared to the case where the ampoule is not settled. It can be done precisely. Thus, the number of manufacturing steps of the magnetic measurement device can be reduced, and the productivity can be improved.

  Application Example 2 In the method of manufacturing a magnetic measurement device according to the application example described above, the predetermined position is provided along a first direction, the ampoule has a longitudinal direction, and the longitudinal direction is the longitudinal direction. It is preferable to arrange | position the said predetermined position so that the said 1st direction may be followed, and to irradiate the said laser beam to the said multiple places along the said 1st direction at the said through-hole formation process.

  According to the manufacturing method of this application example, the ampoule is disposed at a predetermined position such that the longitudinal direction thereof is along the first direction, and a plurality of locations along the longitudinal direction of the ampoule are irradiated with laser light. The through holes can be easily formed. In addition, since it becomes easy to align each of the plurality of locations with the center of the width in the longitudinal direction of the ampoule, airtightness can be more reliably broken in each of the plurality of locations.

  Application Example 3 In the method of manufacturing a magnetic measurement device according to the application example described above, in the through hole forming step, it is preferable that the laser light be scanned and irradiated along the first direction.

  According to the manufacturing method of this application example, since the laser beam is scanned and irradiated along the first direction, through holes can be formed in parallel at a plurality of locations along the longitudinal direction of the ampoule.

  Application Example 4 In the method of manufacturing a magnetic measurement device according to the application example described above, in the through hole forming step, it is preferable to scan the laser beam using a galvano scanner.

  According to the manufacturing method of this application example, laser light can be scanned along the first direction using a galvano scanner.

  Application Example 5 In the method of manufacturing a magnetic measurement device according to the application example described above, it is preferable that, in the through hole forming step, the laser light be branched and irradiated along the first direction.

  According to the manufacturing method of this application example, since the laser beam is branched and irradiated along the first direction, the through holes can be formed in parallel at a plurality of locations along the longitudinal direction of the ampoule.

  Application Example 6 In the method of manufacturing a magnetic measurement device according to the application example, in the through hole forming step, it is preferable to branch the laser beam using a diffraction grating.

  According to the manufacturing method of this application example, the laser beam can be branched along the first direction using the diffraction grating.

  Application Example 7 In the method of manufacturing a magnetic measurement device according to the application example described above, it is preferable that in the through hole forming step, the laser light is irradiated to overlap a part of the plurality of parts. .

  According to the manufacturing method of this application example, the laser light is irradiated to a part of the plurality of parts in an overlapping manner, so that a larger through hole can be formed in a part of the parts. Therefore, the first chamber can be filled with the alkali metal gas in a shorter time.

  Application Example 8 A magnetic measurement apparatus according to this application example is a magnetic measurement apparatus that measures a magnetic field, and is configured to communicate the first chamber, the second chamber, the first chamber, and the second chamber. A gas cell provided with a cell portion having a hole, an ampoule disposed in the second chamber, and an alkali metal gas filled in the first chamber and the second chamber, The chamber is provided with a predetermined position for the ampoule to settle, and the ampoule is formed with a plurality of through holes.

  According to the configuration of this application example, since a plurality of through holes are formed in the ampoule, the probability of breaking the airtightness of the ampoule is enhanced and the alkali inside is improved compared to the case where only one through hole is formed. It is possible to fill the alkali metal gas from the second chamber through the communication hole in a short time by widening the exposed area of the metal material. In addition, since the through holes can be formed by irradiating the laser beam in a state where the ampoule is settled at a predetermined position, the position alignment for irradiating the ampoule with the laser light is performed as compared with the case where the ampoule is not settled. Can be done more accurately. By these, the magnetic measurement apparatus which can improve productivity can be provided.

FIG. 1 is a block diagram showing the configuration of a magnetic measurement device according to the present embodiment. Schematic which shows a structure of the gas cell which concerns on 1st Embodiment. Schematic which shows the structure of the gas cell which concerns on 1st Embodiment, and an ampule. FIG. 6 is a view for explaining the method of manufacturing a gas cell according to the first embodiment. FIG. 6 is a view for explaining the method of manufacturing a gas cell according to the first embodiment. FIG. 6 is a view for explaining the method of manufacturing a gas cell according to the first embodiment. The figure explaining the irradiation method of the laser beam which concerns on 2nd Embodiment. Schematic which shows the example of formation of the through-hole which concerns on the modification 1. FIG. Schematic which shows the structural example of the gas cell which concerns on the modification 2. FIG.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The drawings to be used are appropriately enlarged, reduced, or exaggerated so that the parts to be described become recognizable. Moreover, illustration may be abbreviate | omitted except the component required for description.

First Embodiment
<Configuration of Magnetic Measurement Device>
The configuration of the magnetic measurement device according to the first embodiment will be described with reference to FIG. FIG. 1 is a block diagram showing the configuration of the magnetic measurement device according to the present embodiment. The magnetic measurement device 100 according to the present embodiment is a magnetic measurement device using nonlinear optical rotation (NMOR). The magnetic measurement apparatus 100 is, for example, a biological condition measurement apparatus (such as a magnetocardiograph or magnetoencephalograph) that measures a minute magnetic field generated from a living body, such as a magnetic field from the heart (cardiac magnetism) or a magnetic field from the brain (brain magnetism). Used for The magnetic measurement device 100 can also be used as a metal detector or the like.

  As shown in FIG. 1, the magnetic measurement apparatus 100 includes a light source 1, an optical fiber 2, a connector 3, a polarizing plate 4, a gas cell 10, a polarization separator 5, and a photodetector (Photo Detector: PD) 6. , A light detector 7, a signal processing circuit 8, and a display device 9. In the gas cell 10, an alkali metal gas (alkali metal atoms in a gaseous state) is enclosed. As an alkali metal, cesium (Cs), rubidium (Rb), potassium (K), sodium (Na) etc. can be used, for example. Below, the case where cesium is used as an alkali metal is taken and demonstrated to an example.

  The light source 1 is a device that outputs a laser beam of a wavelength (for example, 894 nm corresponding to the D1 line) corresponding to the absorption line of cesium, for example, a tunable laser. The laser beam output from the light source 1 is so-called CW (Continuous Wave) light having a constant light quantity continuously.

  The polarizing plate 4 is an element that polarizes the laser beam in a specific direction to be linearly polarized. The optical fiber 2 is a member for guiding the laser beam output by the light source 1 to the gas cell 10 side. As the optical fiber 2, for example, a single mode optical fiber that propagates only the fundamental mode is used. The connector 3 is a member for connecting the optical fiber 2 to the polarizing plate 4. The connector 3 is screwed to connect the optical fiber 2 to the polarizing plate 4.

  The gas cell 10 is a box (cell) having a void inside, and the alkali metal vapor (alkali metal gas 13 shown in FIG. 2 (b)) is present in the void (main chamber 14 shown in FIG. 2 (b)). It is enclosed. The configuration of the gas cell 10 will be described later.

  The polarization splitter 5 is an element that splits the incident laser beam into beams of two polarization components orthogonal to each other. The polarization splitter 5 is, for example, a Wollaston prism or a polarization beam splitter. The photodetector 6 and the photodetector 7 are detectors having sensitivity to the wavelength of the laser beam, and output a current corresponding to the light amount of incident light to the signal processing circuit 8. The light detector 6 and the light detector 7 are desirably made of non-magnetic materials, as they may affect the measurement when they generate a magnetic field. The photodetector 6 and the photodetector 7 are disposed on the same side (downstream side) as the polarization splitter 5 with respect to the gas cell 10.

  The arrangement of each part in the magnetic measurement apparatus 100 will be described along the path of the laser beam. The light source 1 is positioned at the uppermost stream of the path of the laser beam, and from the upstream side, the optical fiber 2, connector 3, polarizing plate 4 , The gas cell 10, the polarization splitter 5, and the photodetectors 6, 7 in this order.

  The operation of each part in the magnetic measurement apparatus 100 will be described along the progress of the laser beam. The laser beam output from the light source 1 is guided to the optical fiber 2 and reaches the polarizing plate 4. The laser beam that has reached the polarizing plate 4 becomes linearly polarized light with a higher degree of polarization. The laser beam transmitted through the gas cell 10 excites (optically pumps) alkali metal atoms enclosed in the gas cell 10. At this time, the laser beam is rotated by its polarization plane rotating action according to the strength of the magnetic field. The laser beam transmitted through the gas cell 10 is split by the polarization splitter 5 into beams of two polarization components. The light amounts of the beams of the two polarization components are measured (probed) by the light detector 6 and the light detector 7.

  The signal processing circuit 8 receives a signal indicating the light amount of the beam measured by the light detector 6 and the light detector 7 from each. The signal processing circuit 8 measures the rotation angle of the polarization plane of the laser beam based on each of the received signals. The rotation angle of the polarization plane is expressed as a function based on the strength of the magnetic field in the propagation direction of the laser beam (for example, D. Budker, et al., "Resonant non-linear magneto-optical rotation effect of atoms", review of · See the equation (2) in Modern Physics, USA, American Physical Society, October 2002, Vol. 74, No. 4, pp. 1153-1201, which relates to linear optical rotation In the case of NMOR, almost similar expressions can be used). The signal processing circuit 8 measures the strength of the magnetic field in the propagation direction of the laser beam from the rotation angle of the polarization plane. The display device 9 displays the strength of the magnetic field measured by the signal processing circuit 8.

  Subsequently, a gas cell according to the first embodiment and an ampoule used for the gas cell will be described with reference to FIGS. 2 and 3. FIG. 2 is a schematic view showing the configuration of the gas cell according to the first embodiment. More specifically, FIG. 2 (a) is a schematic plan view of the gas cell, FIG. 2 (b) is a schematic cross-sectional view along the line AA 'in FIG. 2 (a), and FIG. 2 (c) is a gas cell Side view of FIG. FIG. 3 is a schematic view showing the configuration of the gas cell and the ampoule according to the first embodiment. 3 (a) is a schematic cross-sectional view of the gas cell taken along the line B-B 'of FIG. 2 (a), and FIG. 3 (b) is a schematic cross-sectional view along the longitudinal direction of the ampoule. c) is a schematic sectional view along the line CC 'in FIG. 3 (b).

<Configuration of gas cell>
2 (a), (b), (c) and FIG. 3 (a) show a gas cell 10 according to the first embodiment. In FIGS. 2A, 2B, 2C and 3A, the height direction of the gas cell 10 is taken as the Z axis, and the upper side is taken as the + Z direction. The longitudinal direction of the gas cell 10 is taken as the X axis as the first direction, and the right side in FIGS. 2A and 2B is taken as the + X direction. Then, the width direction of the gas cell 10 is taken as a Y-axis as a second direction in the direction intersecting the Z-axis and the X-axis, and the left side in the sheet of FIG. 2C and FIG. Do.

  2 (a) is a plan view of the gas cell 10 from the + Z direction side, and FIG. 2 (b) is a cross-sectional view of the gas cell 10 along the line A-A ', as viewed from the -Y direction side. FIG.2 (c) is the side view which looked at the gas cell 10 from the-X direction side. In the present specification, viewing the gas cell 10 from the + Z direction side as shown in FIG. 2A is referred to as “plan view”. Further, viewing the cross section of the gas cell 10 in a direction intersecting with the cross section, for example, viewing the cross section along the X-axis from the -Y direction side as shown in FIG.

  As shown to Fig.2 (a), the gas cell 10 which concerns on this embodiment is comprised by the cell part 12 and the sealing part 19. As shown in FIG. The cell portion 12 is a box (cell) having an air gap inside, and is formed of, for example, quartz glass. The inner wall of the cell portion 12 may be coated with, for example, paraffin. The thickness of the cell portion 12 is 1 mm to 5 mm, for example, about 1.5 mm.

  The cell unit 12 has a main chamber 14 as a first chamber and a reservoir 16 as a second chamber as an internal space. The main chamber 14 and the reservoir 16 are arranged side by side along the X direction, and communicate with each other through the communication hole 15. An ampoule 20 is disposed in the reservoir 16. The configuration of the ampoule 20 will be described later. An opening 18 is provided on the −X direction side of the reservoir 16, that is, on the opposite side of the communication hole 15.

  The A-A 'line is a line passing the center of the opening 18, the center of the reservoir 16, the center of the communication hole 15, and the main chamber 14 along the X-axis direction. The B-B ′ line is a line passing through the reservoir 16 and the ampoule 20 along the Y-axis direction.

  As shown in FIG. 2 (b), the communication hole 15 is provided on the upper side (+ Z direction side) of the main chamber 14 and the reservoir 16. The opening 18 is provided on the upper side of the reservoir 16. The main chamber 14 and the reservoir 16 inside the cell portion 12 are filled with a gas 13 (hereinafter referred to as an alkali metal gas) in which an alkali metal is evaporated. In the main chamber 14 and the reservoir 16, in addition to the alkali metal gas 13, an inert gas such as a rare gas may be present.

  As shown in FIG. 2 (c), the communication hole 15 is circular. The inner diameter of the communication hole 15 is, for example, about 0.4 mm to 1 mm. The opening 18 is also circular. The inner diameter of the opening 18 is, for example, about 0.4 mm to 1.5 mm. The opening 18 is sealed by the sealing portion 19 so that the cell portion 12 (main chamber 14 and reservoir 16) is sealed. The sealing portion 19 has, for example, a rectangular shape, but may have another shape such as a circular shape. For example, quartz glass is used as a material of the sealing portion 19. The sealing portion 19 is fixed to the cell portion 12 via, for example, a low melting point glass frit (not shown) disposed around the opening 18.

  As shown to Fig.3 (a), the reservoir | reserver 16 has the inclined surface 31a and the inclined surface 31b which incline along a Y-axis direction in the bottom part side (-Z direction side). The inclined surface 31a is inclined from the upper side to the bottom side in the + Y direction, and the inclined surface 31b is inclined from the upper side to the bottom in the -Y direction. The two inclined surfaces 31a and 31b which are inclined in the opposite directions and intersect with each other form a mountain-shaped convex portion in a cross-sectional view along the Y-axis direction. The cross | intersection part 32 which inclined surface 31a, 31b cross | intersects becomes the vertex of the mountain-like convex-shaped part by cross sectional view. In a plan view, the crossing portion 32 extends in a ridge line along the X-axis direction (see FIG. 2A).

<Ampoule Configuration>
As shown in FIG. 3 (b), the ampoule 20 has a longitudinal direction. FIG. 3B shows an X-Z cross section when the ampoule 20 is disposed so that the longitudinal direction thereof is along the X-axis direction. The ampoule 20 is constituted by a hollow glass tube 22. The glass tube 22 is made of, for example, borosilicate glass.

  The glass tube 22 extends along one direction (X-axis direction in FIG. 3B), and both ends thereof are welded. Thus, the hollow glass tube 22 is sealed. In addition, the shape of the both ends of the glass tube 22 is not limited to a round shape as shown in FIG.3 (b), The shape near a plane, the shape in which one part pointed, etc. may be sufficient. The hollow interior of the glass tube 22 is filled with an alkali metal solid (particulate or powdery alkali metal atoms) 24 as an alkali metal material. As the alkali metal solid 24, rubidium, potassium and sodium can be used in addition to cesium as described above.

  FIG. 3B shows a state in which the ampoule 20 (glass tube 22) is sealed. Although the glass tube 22 is in a sealed state when the ampoule 20 is manufactured, when the gas cell 10 is completed, the through hole 21 is formed in the glass tube 22 and the seal is broken (see FIG. 3A). . As a result, the alkali metal solid 24 in the ampoule 20 evaporates and flows out into the gas cell 10, and the space of the cell portion 12 is filled with the alkali metal gas 13 (see FIG. 2B). A gap of, for example, about 1.5 mm in the + Z direction is provided between the upper surface of the ampoule 20 and the inner surface of the cell portion 12 so that the alkali metal solid 24 easily evaporates and flows out from the inside of the ampoule 20. ing.

  FIG. 3C shows a Y-Z cross section in a direction intersecting the longitudinal direction of the ampoule 20. As shown in FIG. As shown in FIG. 3C, the Y-Z cross-sectional shape of the glass tube 22 is, for example, substantially circular, but may be another shape. The outer diameter φ of the glass tube 22 is 0.2 mm ≦ φ ≦ 1.2 mm. The thickness t of the glass tube 22 is 0.1 mm ≦ t ≦ 0.5 mm, and preferably about 20% of the outer diameter φ. If the thickness t of the glass tube 22 is less than 0.1 mm, the glass tube 22 is easily broken. If the thickness t of the glass tube 22 exceeds 0.5 mm, the through hole 21 is formed in the glass tube 22 (Details will be described later) becomes difficult.

<Placement of Ampoule in Reservoir>
As shown in FIG. 3A, the ampoule 20 is disposed at a predetermined position in the reservoir 16 so as to be in contact with the inclined surface 31 b and the side wall 16 a of the reservoir 16. The ampoule 20 is disposed such that its longitudinal direction is along the extending direction of the side wall 16a, that is, the X-axis direction (see FIG. 2A). Thus, the ampoule 20 is held in the reservoir 16 in a stable state.

  The position which projected the opening part 18 arrange | positioned at the-X direction side of the reservoir | reserver 16 to the cross section which followed the B-B 'line | wire in FIG. 3 (a) is shown with a dashed-two dotted line. The opening 18 is provided at a position separated in the + Y direction from the above-described predetermined position where the ampoule 20 is disposed. More specifically, the opening 18 is a position between the predetermined position where the ampoule 20 is disposed and the intersection 32 in the Y-axis direction, that is, a position above the lowest predetermined position on the inclined surface 31 b. It is provided at a position higher than the inclined surface 31 b.

  The opening 18 is a hole for storing the ampoule 20 in the reservoir 16. Since the opening 18 is provided at the upper position of the inclined surface 31 b, the ampoule 20 inserted from the opening 18 moves to the predetermined position which is the lowest position along the inclined surface 31 b.

  The communication hole 15 is preferably provided at a position apart from the above-described predetermined position where the ampoule 20 is disposed. The communication hole 15 is a hole for causing the alkali metal gas 13 in which the alkali metal solid 24 has evaporated in the reservoir 16 to flow out to the main chamber 14. On the other hand, when fragments of the glass tube 22 generated when forming the through hole 21 in the ampoule 20 and the alkali metal solid 24 released from the inside of the ampoule 20 enter the main chamber 14 through the communication hole 15, magnetic measurement The measurement accuracy of the device 100 will be reduced. Therefore, the communication hole 15 is preferably provided at a high position in the reservoir 16. The relative position of the communication hole 15 with respect to the opening 18 is not particularly limited.

  Here, the diameter of the ampoule 20 is φ, the inner diameter of the opening 18 is D1, and the inner diameter of the communication hole 15 is D2. Further, the width of the chamber in the reservoir 16 is W, the height of the chamber is H1, and the height of the intersection 32 is H2. Since it is essential for the ampoule 20 to pass through the opening 18 and it is desirable not to pass through the communication hole 15, D2 <φ <D1. In order to easily store the ampoule 20 in the reservoir 16 and hold it in a stable position, φ / 2 <H2 <(H1−φ) and H2 ≦ (H1−D1). It is preferable that 4φ <W.

  For example, when the diameter φ of the ampoule 20 is 1.0 mm, the inner diameter D1 of the opening 18 can be about 1.2 mm, and the inner diameter D2 of the communication hole 15 can be about 0.4 mm. In addition, the width W of the chamber in the reservoir 16 can be about 5.0 mm, the height H1 of the room can be about 2.5 mm, and the height H2 of the intersection 32 can be about 1.2 mm.

<Method of manufacturing gas cell>
Next, a method of manufacturing the gas cell 10 will be described with reference to FIGS. 4, 5 and 6. FIG.4, FIG.5 and FIG. 6 is a figure explaining the manufacturing method of the gas cell which concerns on 1st Embodiment. 4 (a) is a schematic cross-sectional view of the gas cell 10 corresponding to FIG. 2 (b), and FIGS. 4 (b) and 4 (c) are side views of the gas cell 10 corresponding to FIG. 2 (c). FIG. 5 (a) is a cross-sectional view of the gas cell 10 corresponding to FIG. 3 (a), FIG. 5 (b) is a cross-sectional view of the ampoule 20 corresponding to FIG. 3 (b), and FIG. It is the top view which saw the ampoule 20 of FIG.5 (b) from + Z direction side. 6 (a) and 6 (b) is a figure explaining the irradiation method of a laser beam.

First, the cell unit 12 shown in FIG. 4 (a) is prepared. Although illustration is omitted, for example, a glass plate made of quartz glass is cut to prepare glass plate members corresponding to the respective wall surfaces constituting the cell portion 12. Then, these glass plate members are assembled, and the glass plate members are joined together by an adhesive or welding to obtain a cell portion 12 having a main chamber 14 and a reservoir 16 as shown in FIG. 4 (a). At this stage, the opening 18 of the cell portion 12 is open. The inclined surfaces 31a and 31b (see FIG. 3A) in the reservoir 16 are formed by processing a glass plate member to form an inclined surface, or by arranging the glass plate members obliquely and joining them. Can be configured with

  Subsequently, the ampoule 20 is stored in the reservoir 16 of the cell unit 12 (arrangement step). As shown in FIG. 4 (b), the ampoule 20 is inserted from an opening 18 provided on the reservoir 16 side of the cell unit 12 and stored in the reservoir 16. Since the opening 18 is at a higher position than the inclined surface 31 b, the ampoule 20 inserted from the opening 18 falls onto the inclined surface 31 b. In addition, by providing the opening 18 closer to the intersection 32, the drop when the ampoule 20 is inserted from the opening 18 and dropped onto the inclined surface 31b is reduced, and the ampoule 20 is accidentally damaged by an impact or the like. Reduce the risk of

  The opening 18 is disposed on the upper side of the inclined surface 31 b with respect to the predetermined position where the ampoule 20 is disposed. Therefore, the ampoule 20 moves along the inclined surface 31b toward the bottom indicated by the arrow so as to slide on the inclined surface 31b or to roll the inclined surface 31b with the longitudinal direction as the rotation axis. Then, the ampoule 20 stops at a position in contact with the side wall 16a, that is, at a predetermined position. At this time, the ampoule 20 is guided by the inclined surface 31 b and the side wall 16 a so that the longitudinal direction thereof is along the X-axis direction. Therefore, ampoule 20 can be easily placed at a predetermined position in reservoir 16. The predetermined position in contact with the inclined surface 31 b and the side wall 16 a is a position where the ampoule 20 settles.

  At this stage, as shown in FIG. 3B, the ampoule 20 is in a state in which the hollow glass tube 22 is filled with the alkali metal solid 24 and sealed. The ampoule 20 is filled with the alkali metal solid 24 in the hollow interior of the tubular glass tube 22 under a low pressure environment (ideally under vacuum) close to vacuum, and the both ends of the glass tube 22 are welded and sealed respectively To form. Since alkali metals such as cesium used as the alkali metal solid 24 are rich in reactivity and can not be handled in the atmosphere, they are housed in the cell unit 12 in a sealed state in the ampoule 20 under a low pressure environment.

  Subsequently, as shown in FIG. 4C, degassing in the cell portion 12 is sufficiently carried out, and the cell portion 12 (main chamber 14, communication hole 15, and reservoir) in a state in which there are very few impurities in the internal space. 16) Seal (sealing process). For example, a low melting point glass frit (not shown) is disposed around the opening 18 in at least one of the cell portion 12 and the sealing portion 19 under a low pressure environment (ideally under vacuum) near vacuum, and the cell portion The cell portion 12 is sealed by fixing and sealing the sealing portion 12 and the sealing portion 19.

  Subsequently, as shown in FIG. 5A, the pulse laser beam 70 is applied to the glass tube 22 of the ampoule 20 with the cell portion 12 interposed therebetween, and the glass tube 22 is exposed to a plurality of through holes 21 (FIG. b) Form a) (through hole forming step). Since the laser beam is excellent in directivity and convergence, the through hole 21 can be easily formed in the glass tube 22 by irradiating the pulse laser beam 70.

  Here, it is necessary to form the through hole 21 in the glass tube 22 of the ampoule 20 without damaging the cell portion 12. Therefore, when the cell portion 12 is formed of quartz glass and the glass tube 22 is formed of borosilicate glass, for example, pulsed laser light 70 having a wavelength in the ultraviolet region is used. Light in the ultraviolet range transmits through quartz glass but is slightly absorbed by borosilicate glass. Thereby, the glass tube 22 of the ampoule 20 can be selectively processed to form the through hole 21 without damaging the cell portion 12.

  FIG. 6A schematically shows the irradiation method of the pulse laser beam 70 in the through hole forming step. As shown in FIG. 6A, in the first embodiment, the galvano scanner 72 is used to swing the angle of the pulse laser beam 70 emitted from the laser oscillator (not shown), and the light is collected using the fθ lens 74. As a result, a plurality of beams 70a, 70b, 70c are generated. The fθ lens 74 may have, for example, a focal length of 78 mm.

  As irradiation conditions of the pulse laser beam 70, for example, the pulse width is about 30 nm, and the pulse energy per irradiation point (processing point) is about 50 μJ / pulse to about 200 μJ / pulse. The positions at which the plurality of beams 70a, 70b, and 70c are irradiated are set based on a predetermined position at which the ampoule 20 is disposed. More specifically, the irradiation points of the beams 70a, 70b and 70c are set to three points along the X-axis direction, that is, the longitudinal direction of the ampoule 20. And as shown in FIG.6 (b), the irradiation time T shall be about 100 msec, the space | interval of irradiation shall be about 30 micrometers, and it scans and irradiates along an X-axis direction.

  As described above, the plurality of beams 70a, 70b and 70c are generated from the pulse laser beam 70 and irradiated to the ampoule 20, so that processing is performed in parallel at a plurality of irradiation points (processing points) in the glass tube 22. By this processing, as shown in FIGS. 5B and 5C, the plurality of through holes 21 are formed in the glass tube 22 so as to be aligned in a line along the X-axis direction which is the longitudinal direction of the ampoule 20. Be done.

  Since the plurality of beams 70a, 70b and 70c are irradiated along the longitudinal direction of the ampoule 20, the plurality of through holes 21 can be easily formed in the ampoule 20. Further, since each of the plurality of irradiation points for irradiating the beams 70a, 70b and 70c can be easily aligned with the center of the width in the longitudinal direction of the ampoule, airtightness can be more reliably broken in each of the plurality of through holes 21.

  By forming the through holes 21 in the ampoule 20, as shown in FIG. 3A, the seal of the ampoule 20 is broken in the reservoir 16 of the cell portion 12, and the alkali metal solid 24 evaporates from the inside of the ampoule 20. The metal gas 13 flows out. As shown in FIG. 2 (b), the alkali metal gas 13 that has flowed out into the reservoir 16 flows into the main chamber 14 of the cell portion 12 through the communication hole 15 and is diffused. As a result, the void of the cell portion 12 is filled with the alkali metal gas 13.

  Here, in the through hole forming step, the processing in the depth direction is insufficient and the airtightness of the ampoule 20 is not broken only by the processing of forming the through hole 21 by irradiating the pulse laser beam 70 at one point and forming the through hole 21. There is. In particular, if the ampoule 20 is not held in a stable state in the reservoir 16, the ampoule 20 may be damaged due to a slight inclination or impact when handling the cell portion 12 or an impact due to irradiation with the pulse laser beam 70. It may move and its position may shift. If the position of the ampoule 20 is displaced, the irradiation point of the pulse laser beam 70 to the ampoule 20 is relatively displaced, and the processing in the depth direction becomes insufficient.

  Further, even if the through holes 21 can be formed, the evaporation amount of the alkali metal solid 24 in the ampoule 20 is small from one through hole 21, and it takes a long time to fill the main chamber 14 with the alkali metal gas 13. It may be necessary. Therefore, in order to reliably form the through holes 21 or to increase the evaporation amount of the alkali metal solid 24, the process of irradiating the pulse laser beam 70 to one place is repeated many times, which reduces the number of manufacturing steps. There is a problem that it causes an increase.

  In the present embodiment, the plurality of through holes 21 are formed in parallel in the ampoule 20 by irradiating the pulse laser beams 70 (beams 70 a, 70 b, 70 c) to a plurality of locations of the ampoule 20 in the through hole forming step. Therefore, as compared with the case where the pulse laser beam 70 is irradiated to only one place, the airtightness of the ampoule 20 is broken to increase the probability of forming the through holes 21 and the range to break the airtightness (area where the alkali metal solid 24 is exposed) And the main chamber 14 can be filled with the alkali metal gas 13 in a short time. Further, since the plurality of through holes 21 can be formed in parallel in the ampoule 20 in the through hole forming step, the number of manufacturing steps can be reduced as compared with the case where the step of irradiating the pulse laser beam 70 to one place is repeated.

  Further, in the present embodiment, the bottom of the reservoir 16 has a predetermined position at which the ampoule 20 settles, and the ampoule 20 is disposed in the reservoir 16 at a predetermined position along the X-axis direction, and the position thereof In a stable state. As a result, the through holes 21 can be stably and reliably formed in the ampoule 20, so that the manufacturing yield of the gas cell 10 can be prevented from being reduced and the number of manufacturing steps can be suppressed, and the productivity can be improved.

  In the process of forming the through hole 21 in the ampoule 20, the alkali metal solid 24 may be evaporated and flowed out from the inside of the ampoule 20, and therefore, it is not limited to the formation of the through hole 21; It may be produced and the ampoule 20 may be divided, or the glass tube 22 may be broken. However, in such a case, when the fragments of the glass tube 22 and the alkali metal solid 24 released from the inside of the ampoule 20 intrude into the main chamber 14 through the communication hole 15, the measurement accuracy of the magnetic measuring device 100 is reduced. It will incur.

  In the present embodiment, since the communication hole 15 is provided at a position away from the predetermined position where the ampoule 20 is disposed and at a high position in the reservoir 16, the fragments of the glass tube 22 and the alkali metal solid 24 are Invasion into the main room 14 can be suppressed. As a result, the magnetic measurement device 100 having excellent measurement accuracy can be manufactured and provided.

  Note that the method of manufacturing the magnetic measurement device 100 according to the present embodiment includes the method of manufacturing the gas cell 10 described above. Since the well-known method can be used in processes other than the process of manufacturing the gas cell 10 in the process of manufacturing the magnetic measurement apparatus 100 according to the present embodiment, the description thereof is omitted.

Second Embodiment
The second embodiment is different from the first embodiment in the method of generating a plurality of beams 70a, 70b and 70c from the pulsed laser beam 70 in the method of manufacturing a gas cell, but the other methods are almost the same. The configuration of the magnetic measurement apparatus 100 is the same. The method of manufacturing a gas cell according to the second embodiment will be described with reference to FIG. 7 as to differences from the first embodiment. FIG. 7 is a view for explaining a laser beam irradiation method according to the second embodiment. In addition, about the component which is common in 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

<Method of manufacturing gas cell>
In FIG. 7, the irradiation method of the pulse laser beam 70 in the through-hole formation process which concerns on 2nd Embodiment is shown typically. As shown in FIG. 7, in the second embodiment, the pulse laser beam 70 emitted from a laser oscillator (not shown) is branched into a plurality of beams 70a, 70b and 70c using a diffraction grating 76, and a Fourier transform lens The beam 70a, 70b, 70c is focused on the ampoule 20 using 78.

  As the optical conditions, for example, the wavelength of the pulse laser beam 70 is about 355 nm, the focal length is about 78 mm, the number of branches of the diffraction grating is 3, and the diffraction grating period is about 923 μm. The pulse laser beam 70 is branched into three beams 70 a, 70 b and 70 c along the X-axis direction which is the longitudinal direction of the ampoule 20. As a result, three beams 70a, 70b and 70c are generated in a straight line along the X-axis direction, and the branching interval of each beam is 30 μm.

  As irradiation conditions of the pulse laser beam 70, for example, the pulse width is about 30 nm, the pulse energy per irradiation point (processing point) is about 50 μJ / pulse to 200 μJ / pulse, and the irradiation time is about 300 msec. As a result, processing is performed in parallel at a plurality of irradiation points (processing points) in the glass tube 22 and aligned in a line along the X-axis direction which is the longitudinal direction of the ampoule 20 as in the first embodiment. A plurality of through holes 21 are formed in the glass tube 22 (see FIGS. 5 (b) and 5 (c)).

  The branching intervals of the beams 70a, 70b and 70c can be changed from the above-mentioned branching intervals by using the one with the period of the diffraction grating 76 changed. In addition, when the cross section of the diffraction grating 76 has an analog shape such as a sine waveform, the diffraction efficiency is 90% or more, so that the loss of the pulse laser beam 70 can be reduced. In addition, when a cell-type CGH (computer hologram) is used for the diffraction grating 76, a plurality of beams 70a, 70b and 70c can be irradiated to an arbitrary place.

  Also in the second embodiment, since the plurality of through holes 21 can be formed in parallel in the ampoule 20 in the through hole forming step, the number of manufacturing steps can be reduced as compared to the case of repeating the step of irradiating the laser light to one place. be able to. Further, since the through holes 21 can be stably and surely formed in the ampoule 20, it is possible to suppress the decrease in the manufacturing yield of the gas cell 10 and the increase in the number of manufacturing processes, and to improve the productivity.

  The embodiment described above is merely an aspect of the present invention, and arbitrary modifications and applications are possible within the scope of the present invention. As a modification, for example, the following can be considered.

(Modification 1)
In the method of manufacturing the magnetic measurement device according to the above-described embodiment, the plurality of through holes 21 are formed in the ampule 20 so as to be aligned in the X axis direction in the through hole forming step. It is not limited to the following configuration. The plurality of through holes 21 may be formed along other directions or not in a line. FIG. 8 is a schematic view showing an example of formation of the through hole according to the first modification. 8 (a), (b), (c), (d) and (e) correspond to a plan view of the ampoule 20 of FIG. 5 (c) viewed from the + Z direction side.

  A plurality of through holes 21 may be formed along the Y-axis direction as shown in FIG. 8A, or a plurality of through holes 21 may be formed in the X-axis direction and the Y-axis direction as shown in FIG. The through holes 21 may be formed so as to intersect each other, or may be formed so as to be arranged in a curved shape such as an arc shape as shown in FIG. Alternatively, as shown in FIG. 8D, the plurality of through holes 21 may be formed to be continuous with each other. Furthermore, as shown in FIG. 8 (e), the pulse laser beam 70 (beams 70a, 70b, 70c) overlaps the three through holes 21 (or part of them) formed by percussion processing, trepanning processing, etc. ), And the diameter of the through hole 21 may be processed to be large.

(Modification 2)
The gas cell 10 of the magnetic measurement device 100 of the above embodiment has a mountain-like convex portion in which the crossing portion 32 extends in a ridge line along the X-axis direction on the bottom side of the reservoir 16. Is not limited to such a configuration. For example, the bottom portion side of the reservoir may have a valley-shaped concave portion, or the intersection portion may have a mountain-shaped convex portion extending in a ridge line along the Y-axis direction. FIG. 9 is a schematic view showing a configuration example of a gas cell according to a second modification.

  FIG. 9A shows a schematic cross-sectional view of the gas cell 40 having a valley-shaped concave portion on the bottom side of the reservoir 46. FIG. 9A corresponds to a cross-sectional view taken along the line B-B ′ of FIG. The reservoir 46 of the cell portion 42 has, on the bottom side, inclined surfaces 31a and 31b inclined in opposite directions along the Y-axis direction, and these inclined surfaces 31a and 31b are parallel to the Y-axis direction. The valley-shaped concave part is comprised by cross sectional view. An intersection 33 where the inclined surfaces 31a and 31b intersect each other is a valley bottom of a valley-shaped concave portion in a sectional view.

  Ampoules 20 are arranged at predetermined positions in reservoir 46 at intersections 33 where ampoules 20 settle at contact with inclined surfaces 31a and 31b. At a predetermined position, ampoule 20 is in contact with inclined surface 31a and inclined surface 31b, and is held in a stable state such that the longitudinal direction is along the X-axis direction. If the inclination angle of the inclined surface 31a and the inclination angle of the inclined surface 31b are the same, even if the diameter φ of the ampoule 20 (see FIG. 3A) varies, the center of the ampoule 20 is a plane with the intersection 33 It is arranged at the position where it overlaps visually. Therefore, even if the diameter ア ン プ ル of the ampoule 20 is different or varies, the plurality of beams 70a, 70b, 70c (see FIG. 6A) are irradiated along the longitudinal direction of the ampoule 20 in the through hole forming step. Position can be easily adjusted.

  FIGS. 9B and 9C show a gas cell 50 having an inclined surface 35a and an inclined surface 35b inclined along the X-axis direction on the bottom side of the reservoir 56. FIG. FIG. 9 (b) is a schematic plan view of the gas cell 50, and FIG. 9 (c) is a schematic cross-sectional view taken along the line D-D ′ of FIG. 9 (b). As shown in FIG. 9B, in the reservoir 56 of the cell portion 52, an intersecting portion 36 where the inclined surfaces 35a and 35b intersect with each other extends in a ridge line along the Y-axis direction. Ampoule 20 is arranged such that its longitudinal direction is along the Y-axis direction.

  As shown in FIG. 9C, ampule 20 is positioned at a predetermined position in reservoir 56 such that ampule 20 settles in contact with inclined surface 35a and side wall 56a of reservoir 56, and its longitudinal direction is the Y-axis direction. Be placed along the. Ampoule 20 is in contact with inclined surface 35a and side wall 56a of reservoir 56, and is held in a stable state so that the longitudinal direction thereof is along the Y-axis direction. Therefore, in the through hole forming step, the irradiation positions of the plurality of beams 70a, 70b and 70c (see FIG. 6A) can be easily aligned along the Y-axis direction which is the longitudinal direction of the ampoule 20.

(Modification 3)
The apparatus to which the gas cell 10 according to the above-described embodiment can be applied is not limited to the magnetic measurement apparatus 100. The gas cell 10 can also be applied to an atomic oscillator such as an atomic clock, for example. Although the gas cell used for the atomic oscillator is required to be miniaturized, according to the method for producing a gas cell of the above embodiment, the small gas cell 10 can be stably produced, so that it is suitably used for the compact atomic oscillator it can.

  10, 40, 50: gas cell, 12, 42, 52: cell portion, 13: alkali metal gas (gas of alkali metal), 14: main chamber (first chamber), 15: communicating hole, 16, 46, 56: Reservoir (second chamber), 20: Ampoule, 21: through hole, 24: alkali metal solid (alkali metal material), 70: pulse laser beam (laser beam), 72: galvano scanner, 76: diffraction grating, 100: magnetic Measuring device.

Claims (6)

Placing and sealing an ampoule filled with an alkali metal material in a gas cell;
Forming a plurality of through holes at a plurality of locations of the ampoule by irradiating the ampoule with a plurality of times while scanning the laser light along the first direction .   Placing and sealing an ampoule filled with an alkali metal material in a gas cell;
  Forming a through hole at a plurality of locations along the first direction of the ampoule by simultaneously irradiating the plurality of locations along the first direction with a laser beam. A method of manufacturing a gas cell according to claim 1 or 2 , wherein
In the sealing step, the ampoule is disposed in the second chamber of the gas cell provided with a first chamber, a second chamber, and a communication hole connecting the first chamber and the second chamber. Including
The first chamber and the second chamber are arranged side by side in a second direction,
In a case where a direction orthogonal to the second direction is a third direction and a direction orthogonal to the second direction and the third direction is a fourth direction, the third of the inner walls of the second chamber The inner wall located on one side of the four directions is provided with an inclined surface which is inclined with respect to a virtual plane including the second direction and the third direction,
The ampoule, gas cell manufacturing method according to the fourth direction of most the other hand are located in a first position located on the side wherein Rukoto in the inclined surface. A method of manufacturing a gas cell according to claim 3 , wherein
The first position is provided along the second direction,
The ampoule has a longitudinal direction,
The sealing step includes disposing the ampoule at the first position such that the longitudinal direction is along the second direction;
Wherein in the step of forming the through hole, the gas cell manufacturing method, which comprises irradiating the laser light to the plurality of locations along the second direction. A method of manufacturing a gas cell according to any one of claims 1 to 4 , wherein
In the step of forming the through hole, a method of manufacturing a gas cell is characterized in that the laser light is irradiated to a part of the plurality of parts in an overlapping manner. A cell portion having a first chamber, a second chamber , a communication hole communicating the first chamber and the second chamber, and an opening provided in the second chamber ;
A sealing portion sealing the opening;
An ampoule disposed in the second chamber;
A gas cell comprising an alkali metal gas filled in the first chamber and the second chamber,
The first chamber and the second chamber are arranged side by side in a first direction,
When a direction orthogonal to the first direction is a second direction, and a direction orthogonal to the first direction and the second direction is a third direction, the third of the inner walls of the second chamber The inner wall located on one side of the three directions is provided with an inclined surface which is inclined with respect to a virtual plane including the first direction and the second direction,
The ampoule is disposed at a first position located closest to the one side in the third direction on the inclined surface,
The opening is provided on the other side opposite to the one side in the third direction than the inclined surface, and at a position apart from the first position in the direction in which the inclined surface is inclined,
An atomic oscillator characterized in that a plurality of through holes are formed in the ampoule.

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