WO2008035634A1 - Ionizing device, mass analyzer, ion movability meter, electron capturing detector, and charged particle measuring device for chromatograph - Google Patents

Abstract

This invention provides an ionizing device which can enhance ion density in ionizing a sample molecule using soft X rays. The ionizing device (1) comprises a body part (21), a soft X-ray tube (3), and electrodes (4), (5). The body part (21) comprises an ionization chamber (2) which extends in a predetermined axis direction to ionizing the sample molecule, an introduction port (22) for introducing a sample molecule and a base gas into the ionizing chamber (2) (in which the ionizing chamber (2) and the introduction port (22) may be provided separately from each other), and an exhaust port (23) for discharging a sample molecule ion. The soft X ray tube (3) comprises an electron source (31) and a target part (32) for receiving electrons from the electron source (31) to generate a soft X ray. The electrodes (4), (5) are provided respectively on the one end side and other end side of the ionizing chamber (2). The soft X ray outgoing axis direction of the soft X ray tube (3) crosses the above predetermined axis direction. An electrode (32b) and the electrode (5) provided in the target part (32) are shortcircuited from each other. The center axis direction of the introduction port (22) crosses the soft X ray outgoing axis direction.

Description

 Specification

 Ionizer, mass spectrometer, ion mobility meter, electron capture detector, and charged particle measurement device for guchimatograph

 Technical field

 [0001] The present invention relates to an ionizer used for a mass analyzer, an ion mobility meter, an electron capture detector, a charged particle measuring device for chromatography, and the like, and a mass analyzer, an ion The present invention relates to a mobility meter, an electron capture detector, and a charged particle measuring device for chromatography.

 Background art

 In recent years, as an ionization apparatus used in an atmospheric pressure environment, for example, a device using a radioisotope force or radiation emitted from the device or a device using corona discharge is generally used. . However, devices that use radiation are not easily managed, and devices that use corona discharges are contaminated due to electrode defects during discharge, degradation of ionization efficiency, or sample decomposition! / There's a problem.

 [0003] As an ionization apparatus that can avoid these problems, soft X-rays as described in, for example, Japanese Patent Application Laid-Open No. 2001-68053 (hereinafter referred to as “Patent Document 1”) are currently used. Devices for ionizing sample molecules are being developed (see).

 Disclosure of the invention

 Problems to be solved by the invention

 [0004] However, the structure described in Patent Document 1 has the following problems! For example, as shown in FIG. 31A, when the angle formed between the electrode 203 provided at the end opposite to the ion discharge port 202 of the ionization chamber 201 and the axis C in which the ionization chamber 201 extends is an acute angle. In the space between the electrode 203 and the electrode 205 of the X-ray tube 204, it is difficult to carry out ions that are formed so that the electric field E is difficult to enter! /. Also, ions formed in the vicinity of the electrode 205 of the X-ray tube 204 do not reach the ion introduction grid 206 due to the shape of the electric field, and the majority are absorbed by the wall surface of the ionization chamber 201 and only a part of the grid 206 is absorbed. It is easy to take the trajectory to reach (orbit I in the figure).

In addition, as shown in FIG. 31B, the ionization chamber 211 has an end opposite to the ion discharge port 212. When the louvered electrode 213 is provided, the electric field E is difficult to be formed in the space between the louvered electrodes 213, and ions formed there are difficult to be carried out. Also, in the ions formed in the vicinity of the electrode 205 of the X-ray tube 204, only the ions that do not overlap with the louvered electrode 213 move along the electric field, but this is also ionized from the shape of the formed electric field. It collides with the wall surface of chamber 211 and is easily neutralized (orbit 1 in the figure). In other words, the efficiency of extracting the formed ions from the ionization chamber is poor, and the ion density may be low.

Yes

 [0006] The present invention has been made in view of the above-described problems, and an ionization apparatus capable of increasing the ion density extracted from the ionization chamber when ionizing sample molecules using soft X-rays, and the ionization It is an object of the present invention to provide a mass analyzer, an ion mobility meter, an electron capture detector, and a charged particle measuring apparatus for chromatography.

 Means for solving the problem

[0007] In order to solve the above problems, an ionization apparatus according to the present invention includes (1) an ionization chamber extending in a predetermined axial direction and ionizing sample molecules, and a first introduction port for introducing the sample molecules into the ionization chamber And a second inlet for introducing the base gas into the ionization chamber that is also used as the first inlet or independently, and one end of the ionization chamber in the predetermined axial direction, and is ionized in the ionization chamber A main body portion having a discharge port for discharging sample molecules; (2) an electron source; a target portion that receives electrons from the electron source to generate soft X-rays; and a vacuum that houses the electron source and the target portion. A soft X-ray source having a container and a window for transmitting the soft X-rays emitted from the target part to be emitted to the outside of the vacuum container, and irradiating the transmitted soft X-rays into the ionization chamber; (3) Provided at the outlet, A first electrode having an opening through which the sampled sample molecules pass, and (4) a second electrode provided on the opposite side of the first electrode in the predetermined axial direction of the ionization chamber. The soft X-ray emission axis direction of the soft X-ray source intersects the predetermined axial direction, and the angle formed between the surface of the second electrode facing the ionization chamber and the predetermined axial direction is 70 degrees or more and 120 degrees or less Preferably, it is 80 degrees or more and 120 degrees or less.

In this ionization apparatus, an electric field along a predetermined axial direction is formed in the ionization chamber by applying a potential difference between the first electrode and the second electrode. The first introduction port Sample molecules are introduced into the ionization chamber, and a base gas (such as nitrogen gas) is introduced from the second inlet (provided the same as or independent from the first inlet). When the base gas is irradiated with soft X-rays, the base gas is ionized and the sample is subjected to ion molecule reaction (proton transfer, ion addition, charge transfer, etc.) or electron addition between the ionized base gas and sample molecules. Molecules are ionized. The sample molecular ions generated in this way are accelerated by the electric field and discharged from the ionization chamber to the outside of the ionization chamber.

 [0009] In this ionization apparatus, the soft X-ray emission axis direction of the soft X-ray source and the predetermined axial direction of the ionization chamber (that is, the ion movement direction) intersect each other, and further, the second ion beam facing the ionization chamber. The angle between the surface of the electrode and the predetermined axis is 70 ° or more and 120 ° or less, preferably 80 ° or more and 120 ° or less. More preferably, this angle is substantially vertical. Here, when the surface of the second electrode includes a plurality of planes or curved surfaces, the main part only needs to satisfy the angle condition. As a result, an electric field is effectively formed in the ionization chamber, and ions (in the following description, when simply referred to as “ions”, both base gas ions and sample molecule ions are indicated). Since it can be discharged efficiently to the discharge port, the ion density extracted from the ionization chamber can be increased.

 [0010] Further, in the ionization apparatus according to the present invention, a target electrode is provided in the target portion, the force that short-circuits the target electrode and the second electrode, and the target electrode and the second electrode. It is preferable to further include a control unit that controls the applied potential to be the same potential. As a result, an electric field that can effectively focus ions near the central axis of the ionization chamber can be generated. In the ionization chamber, more ions are generated in the region closer to the soft X-ray source. According to this ionization apparatus, the ions generated in the region near the soft X-ray source are generated by the soft X-ray. Quickly leave the source and focus near the central axis of the ionization chamber. Therefore, the ionization of the base gas and sample molecules can be efficiently performed in the vicinity of the soft X-ray source, so that the ion density can be increased. Also, according to this ionization device, collisions between ions and the like provided on the target portion of the soft X-ray source and ions can be suppressed, so that neutralization (neutralization) of ions is reduced and ion density is reduced. Increase the power with S.

[0011] The short circuit between the second electrode and the target electrode is that both electrodes are in contact with each other. It is preferable to implement | achieve by. Thus, the second electrode and the target electrode can be short-circuited with each other with a simple configuration.

[0012] Further, the ionization apparatus preferably includes at least one of window material force silicon and silicon nitride that transmits soft X-rays in the window. As a result, soft X-rays with smaller energy can be extracted from the soft X-ray source. Near the window of the soft X-ray source

V, the correlation coefficient when soft X-rays react with gas increases as the soft X-ray energy decreases! Therefore, according to this ionization apparatus, the ion density can be further increased by using soft X-rays having lower energy.

 [0013] In the ionization apparatus, the inner surfaces of the ionization chambers except for the surfaces of the soft X spring source and the second electrode may be made of an insulating member. This effectively suppresses secondary electron emission due to soft X-ray irradiation in the ionization chamber, so that neutralization (neutralization) of sample molecule ions is suppressed when generating positive sample molecule ions. The ion density of sample molecular ions can be further increased. In this case, the ionization apparatus may further include an intermediate electrode between the first electrode and the second electrode, and an end of the intermediate electrode on the ionization chamber side may be covered with an insulating member. Thereby, the electric field between the first electrode and the second electrode can be more effectively formed, and the emission of secondary electrons from the intermediate electrode can be effectively suppressed. In addition, the inner surface of the opening of the first electrode is continuous with the inner surface of the discharge port of the ionization chamber, or is positioned outside the inner surface of the discharge port with respect to the central axis of the discharge port. Also good. Thereby, emission of secondary electrons from the first electrode can be effectively suppressed.

 [0014] Conversely, the ionization apparatus further includes an intermediate electrode between the first electrode and the second electrode, and includes a soft X-ray source, the second electrode, and an intermediate electrode protruding from the inner surface of the ionization chamber. The inner surface of the ionization chamber excluding the respective surfaces of the end portions on the ionization chamber side may be made of an insulating member. As a result, the secondary electrode is irradiated with soft X-rays and many secondary electrons are emitted, which helps to generate ions and increase the ion density when generating negative sample molecular ions.

[0015] In the ionization apparatus, the window portion of the soft X-ray source is disposed so as to recede from the inner surface of the ionization chamber along the predetermined axial direction, and is provided between the window portion and the ionization chamber. It is preferable to further include another window portion that transmits soft X-rays and is short-circuited with the window portion. Soft By arranging the X-ray source window so as to recede from the inner surface of the ionization chamber, it is possible to limit the soft X-ray irradiation range in the ionization chamber and reduce the generation of secondary electrons in the ionization chamber. In addition, by providing another window with the same potential as the window between the window of the soft X-ray source and the ionization chamber, sample molecules and the like stay in the space generated by the retraction of the soft X-ray source. This can be prevented and the above-described electric field in the ionization chamber can be effectively formed.

 In the ionization apparatus, the window portion of the soft X-ray source is disposed so as to recede from the inner surface along the predetermined axial direction in the ionization chamber, and a collimator is provided between the window portion and the ionization chamber. You may also prepare. This limits the soft X-ray irradiation range in the ionization chamber, reduces the generation of secondary electrons in the ionization chamber, and easily short-circuits the target electrode and the second electrode via a collimator. Can be. In addition, compared with the case where the soft X-ray source window is simply retracted, the soft X-ray irradiation range is effectively limited even if the distance between the soft X-ray source target and the ionization chamber is made shorter. As a result, soft X-rays with low energy (ie, a high correlation coefficient with the base gas) can be used efficiently. Therefore, the ion density can be further increased.

[0017] The ionization apparatus further includes a seal member that keeps the ionization chamber airtight, and the seal member is provided around the soft X-ray source and includes at least one of glass fiber and ceramic fiber. Good. Alternatively, the seal member may be an annular member including a metal or a carbon-based material provided between the X-ray source and the ionization chamber. As a result, even under a high temperature environment of, for example, around 300 ° C., the seal member is not thermally decomposed with very little outgassing from the seal member, so that the airtight state of the ionization chamber can be suitably maintained.

[0018] The ionization apparatus may further include a heat retaining container that accommodates the main body portion and maintains the temperature at a high temperature, and the electron source may be located outside the heat retaining container. In an ionizer, the ionization chamber may be heated to promote ionization, prevent clustering, or prevent contamination with samples. In such a case, the following effects can be obtained by arranging the electron source of the soft X-ray source outside the heat insulating container. For example, when the electron source is a filament, disposing the filament outside the thermal insulation container can suppress heat consumption and disconnection, and extend the life of the soft X-ray source. Even when using an electron source other than a filament, The electron source can be placed in a temperature environment suitable for operation.

[0019] Further, the ionization apparatus may have a cold cathode as an electron source of a soft X-ray source! As a result, the temperature rise of the electron source can be suppressed as compared with the case where a filament is used as the electron source, so that the temperature rise in the ionization chamber can be prevented and the ionization reaction can be generated stably. Also, for example, when applying this ionization device to an ion mobility meter, it is possible to suppress the rise in temperature of the drift chamber following the ionization chamber and increase the measurement accuracy.

[0020] In the ionization apparatus, the soft X-ray source may further include a deflecting unit that deflects electrons emitted from the electron source. By scanning electrons using this deflection unit, it is possible to generate soft X-rays in the target part! /, And extremely short time / width (in the form of temporal pulses). The amount of time generated can be easily changed in a Norse shape over time, and it becomes easy to emit sample molecular ions in a nose shape in time. This eliminates the need for a gate shatter that has been conventionally used to emit sample molecular ions in a temporal noise shape, and simplifies the structure of the ionization apparatus.

 [0021] The ionization apparatus may further include a second soft X-ray source having a tube axis extending in a predetermined axial direction. Thereby, ionization efficiency improves more.

 [0022] In addition, a mass analyzer according to the present invention includes the above-mentioned! /, Any of the ionization devices. According to this mass analyzer, sample molecules can be ionized at high density. Analysis can be performed with higher accuracy.

 [0023] Further, an ion mobility meter according to the present invention is provided with the above-mentioned! /, Which is an ionization device, and according to this ion mobility meter, sample molecules can be ionized at a high density. Sample molecule identification and quantitative analysis can be performed with higher accuracy.

 [0024] In addition, an electron capture detector according to the present invention is provided with the above-mentioned! /, Any ionization device, and according to this electron capture detector, sample molecules can be ionized at high density. Quantitative analysis of sample molecules can be performed with higher accuracy.

[0025] Further, a charged particle measuring apparatus for chromatographs according to the present invention includes the above-mentioned! /, Deviation ionization apparatus, and according to the charged particle measuring apparatus for chromatographs, a sample Since molecules can be ionized at high density, quantitative analysis of sample molecules can be performed with higher accuracy. Can do.

 The invention's effect

 According to the ionization apparatus of the present invention, when ionizing sample molecules using soft X-rays, the ion density taken out from the ionization chamber can be increased, and the mass analyzer, ion mobility meter according to the present invention, According to the electron capture detector and the charged particle measuring apparatus for chromatograph, analysis and the like can be performed with high accuracy by the increased ion density.

 Brief Description of Drawings

 FIG. 1 is a cross-sectional view showing a configuration of an ionization apparatus according to Embodiment 1 of the present invention.

 FIG. 2 is a simplified diagram of the ionization apparatus of Example 1.

 FIG. 3 is a cross-sectional view showing an example of the shape of the electrode surface facing the ionization chamber.

 FIG. 4 is a cross-sectional view showing a configuration of an ionization apparatus according to a first modification.

 FIG. 5 is a cross-sectional view showing a configuration of an ionization apparatus according to a second modification.

 FIG. 6 is a cross-sectional view showing a configuration of an ionization apparatus according to a third modification.

 FIG. 7 is a cross-sectional view showing a configuration of an ionization apparatus according to a fourth modification.

 FIG. 8 is a cross-sectional view showing a configuration of an ionization apparatus according to a fifth modification.

 FIG. 9 is a cross-sectional view showing a configuration of an ionization apparatus according to a sixth modification.

 FIG. 10 is a cross-sectional view (a) showing a configuration of an ionization apparatus according to a seventh modification, and a cross-sectional view (b) taken along the line XX.

 FIG. 11 is a cross-sectional view (a) showing a configuration of an ionization apparatus according to an eighth modification, and a cross-sectional view taken along the line XI-XI.

 FIG. 12 is a cross-sectional view showing the main parts of the configuration of an ionization apparatus according to a ninth modification.

 FIG. 13 is a cross-sectional view showing the main parts of the configuration of an ionization apparatus according to a tenth modification.

 FIG. 14 is a cross-sectional view showing a main part of a configuration of an ionization apparatus according to an eleventh modification.

 FIG. 15 is a cross-sectional view showing the main parts of the configuration of an ionization apparatus according to a twelfth modification.

 FIG. 16 is a cross-sectional view showing the main parts of the configuration of an ionization apparatus according to a thirteenth modification.

 FIG. 17 is a view in which a seal member is arranged between the flange portion and the ionization chamber in the thirteenth modification.

FIG. 18 is a cross-sectional view showing the main parts of the configuration of an ionization apparatus according to a fourteenth modification. FIG. 19 is a diagram in which a window material is installed on the end surface of the collimator on the ionization chamber side in the fourteenth modification.

 FIG. 20 is a cross-sectional view showing a configuration of an ionization apparatus according to a fifteenth modification.

 FIG. 21 is a cross-sectional view showing a configuration of an ionization apparatus according to a sixteenth modification.

 FIG. 22 is a cross-sectional view showing a configuration of a mass spectrometer (MS) of Example 2 of the present invention.

 FIG. 23 is a cross-sectional view showing a configuration of an ion mobility meter (IMS) of Example 3 of the present invention.

 FIG. 24 is a cross-sectional view showing a configuration of an electron capture detector of Example 4 of the present invention.

 FIG. 25 is a cross-sectional view showing another configuration of the electron capture detector.

 FIG. 26 is a cross-sectional view showing a configuration of a charged particle measuring apparatus for chromatographs in Example 5 of the present invention.

 FIG. 27 is a cross-sectional view showing another modification of the present invention.

 FIG. 28 is a cross-sectional view showing still another modification of the present invention.

 FIG. 29 is a cross-sectional view showing still another modification of the present invention.

 FIG. 30 is a cross-sectional view showing still another modification of the present invention.

 FIG. 31 is a diagram showing a structure of an ionization device described in Patent Document 1.

 Explanation of symbols

 [0028] 1 ··· Ionizer, 2 ··· Ionization chamber, 3 ··· Soft X-ray tube, 4, 5 ··· electrode, 6 ··· Seal mechanism, 9

… Conductive base, 11, 33… window, 11a, 15, 33a… window material, lib… flange, 13… collimator, 13a… through, 17, 19 ··· Insulation container, 21 ··· Main body ^ 22, 26 ················································· 25 41 ······························ 60 ·························································, 100d ... charged particle measuring device for chromatographs.

 BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of an ionization apparatus, a mass analyzer, an ion mobility meter, an electron capture detector, and a charged particle measuring apparatus for chromatography will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Dimensions in each drawing include exaggerated parts for explanation. Rarely, the dimensional ratios of the individual elements do not necessarily match the actual ones.

 Example 1

 FIG. 1 is a cross-sectional view showing a configuration of an ionization apparatus 1 that is an example of an embodiment of the present invention. Figure 1 shows the XYZ Cartesian coordinate system for illustration. As shown in FIG. 1, the ionization apparatus 1 includes a main body 21 having an ionization chamber 2, a soft X-ray tube 3, electrodes 4 and 5, and a seal mechanism 6.

 [0031] The ionization chamber 2 is a space provided for ionizing sample molecules, and is maintained at almost atmospheric pressure. The ionization chamber 2 is formed in a cylindrical main body 21 having openings 21a and 21b at both ends, and extends in a predetermined axial direction (X-axis direction in this embodiment). In the present embodiment, a cylindrical member having a circular outer peripheral cross-sectional shape in the YZ plane and a rectangular inner peripheral cross-sectional shape is used as the main body 21. However, the vicinity of the later-described outlet 23 of the ionization chamber 2 has a circular shape inscribed in a rectangle. The main body 21 is made of an electrically insulating material.

 [0032] In the main body 21, an introduction port 22 and a discharge port 23 are further formed. The introduction port 22 is an opening that doubles as an introduction port for introducing sample molecules into the ionization chamber 2 and an introduction port for introducing a base gas. The central axis direction of the introduction port 22 is set so as to intersect the soft X-ray emission axis direction of the soft X-ray tube 3. In this embodiment, the central axis direction of the inlet 22 is set in the Y-axis direction, and the soft X-ray emission axis direction of the soft X-ray tube 3 is set in the Z-axis direction. The inlet 22 is preferably formed at a position and angle whose central axis is orthogonal to the soft X-ray emission axis B of the soft X-ray tube 3! /.

 [0033] The discharge port 23 is an opening for discharging sample molecule ions generated in the ionization chamber 2. The discharge port 23 is formed in the main body 21 on one end side of the ionization chamber 2 in a predetermined axial direction (X-axis direction). In this embodiment, the opening 21a is the discharge port 23. That is, the ionization chamber 2 communicates with the external space through the discharge port 23. The discharge port 23 is preferably formed at a position and an angle with the central axis A orthogonal to the soft X-ray emission axis B of the soft X-ray tube 3 and also orthogonal to the central axis of the inlet 22.

The soft X-ray tube 3 is a soft X-ray source for irradiating the inside of the ionization chamber 2 with soft X-rays. The soft X-ray tube 3 of this embodiment is a soft X-ray tube that communicates with the inner surface of the ionization chamber 2 in the main body 21. Attached to the inlet 24 and fixed to the main body 21. The soft X-ray tube 3 includes a vacuum container 30, an electron source 31, a target part 32, and a window part 33.

 The vacuum container 30 is a container for housing the electron source 31 and the target unit 32. The vacuum container 30 of the present embodiment has a cylindrical shape whose longitudinal direction is the soft X-ray emission axis direction (Z-axis direction) and is hermetically sealed to keep the inside in a vacuum state.

 [0036] The electron source 31 is a part for emitting electrons such as thermal electrons, photoelectrons, and field emission electrons. The electron source 31 is arranged on one end side in the longitudinal direction of the vacuum container 30 (side away from the ionization chamber 2). The electron source 31 of this embodiment includes a filament 31a and an electrode (not shown) for focusing and accelerating electrons. The electron source 31 may include a cold cathode, for example, instead of the filament 31a. The electron source 31 is preferably variable in the amount of emitted electrons and its acceleration voltage!

 [0037] The target part 32 is a part for receiving electrons from the electron source 31 and generating soft X-rays. The target portion 32 is disposed on the other end side in the longitudinal direction of the vacuum vessel 30 (side closer to the ionization chamber 2). The target portion 32 includes a target 32a made of tandastain or the like that emits soft X-rays by electron collision, and a target electrode 32b that applies a potential to the target 32a. The target electrode 32b is formed in a flange shape so as to surround the outer periphery of the target 32a, and is sealed and fixed to the other end of the vacuum vessel 30.

 The window 33 is a member that transmits soft X-rays emitted from the target 32 and emits the X-rays to the outside of the vacuum vessel 30 (that is, inside the ionization chamber 2). The window 33 includes a window member 33a that transmits soft X-rays that hold the target 32a on the vacuum side, and an electrode that applies a potential to the window member 33a (in this embodiment, the target electrode 32b also serves). Including. The window member 33a is a flat plate member made of a material that transmits soft X-rays, such as aluminum, titanium, beryllium, silicon, or silicon nitride. In particular, when the window member 33a contains at least one of silicon and silicon nitride, it is possible to emit Si X-rays with lower energy than that of a normal soft X-ray tube. The window material 33a is sealed to the target electrode 32b. When an electrode for applying a potential to the window member 33a is provided separately from the target electrode 32b, the electrode of the window member 33a and the target electrode 32b may be short-circuited to have the same potential.

The electrode 4 is the first electrode in the present example. The electrode 4 has a predetermined axial direction (X-axis direction ) On one end side of the ionization chamber 2. The electrode 4 is provided so as to cover the discharge port 23 (opening 21a) of the ionization chamber 2, and has an opening 41 through which ionized sample molecules pass. The electrode 4 of the present embodiment has a mesh portion 42 formed in a net shape (mesh shape), and constitutes a large number of gap force openings 41 formed in the mesh portion 42.

 [0040] The electrode 5 is the second electrode in the present embodiment. The electrode 5 is provided on the other end side with respect to the electrode 4 in a predetermined axial direction (X-axis direction) of the ionization chamber 2. The electrode 5 extends in the Z-axis direction so as to intersect perpendicularly with a predetermined axial direction, and is provided so as to block the opening 21b of the ionization chamber 2 by a flat portion 5b facing the ionization chamber 2, and serves as a termination electrode. Function . The electrode 5 is in contact with the target electrode 32b of the soft X-ray tube 3. As a result, the target electrode 32b and the electrode 5 are short-circuited to each other and are substantially at the same potential. In addition, the short circuit between the electrode 5 and the target electrode 32b may be realized by connecting via, for example, a conductive wiring or a spring material in addition to the direct contact with each other. The electrodes 4 and 5 are electrically connected to an external power source of the ionization apparatus 1 through lead terminals 43 and 50, respectively.

 [0041] The sealing mechanism 6 is provided around the soft X-ray source 3 and seals the gap between the soft X-ray tube inlet 24 and the soft X-ray tube 3 to keep the ionization chamber 2 airtight. Mechanism. The seal mechanism 6 has a seal member 60 provided around the soft X-ray source 3 to keep the ionization chamber 2 airtight. Considering the use of force ionizer 1, which uses an O-ring or gasket, in a high-temperature environment, for example, a perfluoro-type O-ring is used as the seal member 60. And even better.

 [0042] Further, the seal mechanism 6 is fixed to the main body 21 and communicates with the soft X-ray tube inlet 24, and a cylindrical support member 61 that supports the seal member 60 from obliquely below, and a support member 61 A cylindrical moving member 62 that can be screwed inwardly and moved in the vertical direction (Z-axis direction), and an annular member 63 that is disposed below the moving member 62 and contacts the seal member 60 obliquely from above. . In this seal mechanism 6, the seal member 60 is moved to the vacuum container 30 of the soft X-ray tube 3 by the support member 61 and the annular member 63 by rotating the moving member 62 to move downward (Z-axis negative direction). Pressed. As a result, the gap between the soft X-ray tube inlet 24 and the soft X-ray tube 3 is sealed.

[0043] The operation of the ionization apparatus 1 of the present embodiment having the above-described configuration and the resulting operation Use and effects will be described. In the ionizer 1, first, a predetermined voltage is applied to the electrodes 4 and 5, and a potential difference is applied between the electrodes 4 and 5. As a result, an electric field along a predetermined axial direction (X-axis direction) is formed inside the ionization chamber 2. At this time, when positive sample molecular ions are generated inside the ionization chamber 2, the potential of the electrode 4 is set lower than the potential of the electrode 5. Conversely, when negative sample molecular ions are generated, the potential of electrode 4 is set higher than the potential of electrode 5. More specifically, when a positive sample molecular ion is generated, it is preferable to satisfy the potential relationship of (electrode 4) <(target electrode 32b) ≤ (electrode 5). When ions are generated, it is preferable to satisfy the potential relationship of (electrode 5) ≤ (target electrode 32b) <(electrode 4).

 Subsequently, sample molecules are introduced into the ionization chamber 2 from the inlet 22, and the same inlet 22

 Base gas (nitrogen gas, etc.) is introduced from (or a different inlet! /). When soft X-rays are irradiated from the soft X-ray source 3 to the base gas, the base gas is ionized, and ion molecule reactions (proton transfer, ion addition, charge transfer, etc.) between the ionized base gas and sample molecules Sample molecules are ionized by electron addition. This reaction is different from photoionization, in which sample molecules are directly ionized by vacuum ultraviolet light (VUV). In addition, for the purpose of increasing ionization efficiency, a dopant gas that is easily ionized may be included in the base gas. When introducing sample molecules and base gas from different inlets, the base gas inlet is provided upstream from the sample molecule inlet, the base gas is ionized first, and the sample molecules and base gas ions are downstream. It is good to react. The sample molecules may be fine powder solids such as nanoparticles and PM (particulate matter) in addition to gas.

[0045] The ionized sample molecules are accelerated by the electric field formed by the electrodes 4 and 5, and are discharged to the outside of the ionization chamber 2 through the opening 41 of the mesh portion 42 of the electrode 4 provided at the discharge outlet 23. The At this time, the base gas used for ionization is discharged together with the sample molecular ions. As a driving force for releasing sample molecular ions, an electric field formed around the mesh portion 42 may be used, or a gas flow supplied to the ionization chamber 2 may be used for IJ. Further, the discharge port 23 may be arranged to face the electrode 5 as in the present embodiment. However, it may be provided in a different direction. When positive ions are generated, electrons generated by ionization are collected by the electrode 5.

 [0046] In the ionization apparatus 1 of the present embodiment, the soft X-ray emission axis direction (Z-axis direction) of the soft X-ray source 3 and a predetermined axial direction (X-axis direction, that is, the ion movement direction). Intersect with each other (orthogonal in this embodiment), and further, a predetermined axial direction of the ionization chamber 2 (X-axis direction in the present embodiment) and the surface of the electrode 5 facing the ionization chamber 2 (planar portion) ) The angle formed by 5b (parallel to the YZ plane in this example) is vertical. Further, the target electrode 32b provided in the target portion 32 and the electrode 5 are short-circuited to have the same potential. Thereby, a substantial termination electrode of the ionization chamber 2 is constituted by the electrode 5 and the target electrode 32b. That is, the substantial termination electrode includes a portion (electrode 5) constituting the end of the ionization chamber 2 in a predetermined axial direction (X-axis direction) and an ionization chamber along the predetermined axial direction (X-axis direction). 2 is included in the negative direction of the X axis and the positive direction of the Z axis with respect to the ionization chamber 2.

[0047] The substantial termination electrode generates an electric field that can effectively focus the ions near the central axis of the ionization chamber 2 in the region near the window 33 inside the ionization chamber 2. . Referring to FIG. 2 in which this structure is simplified, an effective electric field E is formed in the ionization chamber 2 from the electrode 5 to the electrode 4, and the electric field E is the central axis of the ionization chamber 2 in the vicinity of the window 33. It is formed facing the direction. In the ionization chamber 2, more ions are generated in the region closer to the window portion 33, but ions generated in the region closer to the window portion 33 are quickly separated from the vicinity of the window portion 33 due to the action of the electric field described above. Focuses near the center axis of 2 (ion trajectory 1 in the figure). Therefore, according to the ionization apparatus 1 of the present embodiment, the ionization of the base gas and the sample molecules can be efficiently performed in the vicinity of the window 33, so that the density of generated ions can be increased. This is not limited to the case where the angle formed by the predetermined axial direction of the ionization chamber 2 and the flat portion 5b of the electrode 5 is vertical, but an angle close to vertical, specifically 70 ° or more and 120 ° or less, preferably The angle should be between 80 ° and 120 °. When the flat portion 5b is inclined with respect to a predetermined axial direction, it is preferable to incline the flat portion 5b of the electrode 5 without changing the predetermined axial direction of the ionization chamber 2. Further, the shape of the surface of the electrode 5 facing the ionization chamber 2 is not limited to a planar shape. For example, a spherical shape as shown in Fig. 3 (a) Surface 5c, surface 5d with a flat central surface as shown in Fig. 3 (b), part of the surface is flat and the other part is curved as shown in Fig. 3 (c). Various shapes are possible for the surface of electrode 5, such as surface 5e. If the entire surface is not flat, the main part centering on the axis A of the surface only needs to satisfy the angle condition described above.

[0048] Also, according to the ionization apparatus 1 of the present embodiment, collision between ions and the target electrode 32b of the soft X-ray source 3 can be suppressed by the action of the electric field described above. Therefore, neutralization (neutralization) of ions can be reduced, and the density of the generated sample molecular ions can be further increased.

 [0049] Further, according to the ionization apparatus 1 of the present embodiment, when generating positive sample molecular ions, the potential of the target electrode 32b can be set to the same positive potential as the electrode 5 (for example, +3 kV). The potential of the filament 31a can be increased by the potential of the target electrode 32b (for example, 3 kV to 7 kV with respect to the ground potential). As a result, the potential difference between the soft X-ray tube 3 that is generally at a high pressure and the ground potential can be kept low, and the pressure resistance performance of the peripheral members in contact with the soft X-ray tube 3 can be improved.

 [0050] Also, according to the ionization apparatus 1 of the present embodiment, the soft X-ray emission axis direction (Z-axis direction) of the soft X spring source 3 and the ion emission direction (X-axis direction) intersect! Therefore, the soft X-ray irradiation range is limited, and the soft X-rays can be prevented from leaking outside the ionization chamber 2. Therefore, the generation of unintended ions and secondary electrons outside the ionization chamber 2 can be suppressed.

 [0051] Further, as in the present embodiment, the soft X-ray tube 3 is preferably variable in the amount of electrons from the electron source 31 and its acceleration voltage. This makes it possible to adjust the amount of base gas ions generated according to the amount of sample molecules to be ionized. Therefore, generation of unnecessary base gas ions can be suppressed, and problems such as diffusion of sample molecule ions due to space charge effects and charge-up in the ionization chamber 2 can be solved.

 [0052] Further, as in the present embodiment, it is preferable that the target electrode 32b and the electrode 5 are in contact with each other. As a result, the force S that short-circuits the target electrode 32b and the electrode 5 to each other with a simple configuration can be achieved.

[0053] Further, as in this embodiment, the window member 33a of the soft X-ray tube 3 preferably includes at least one of silicon and silicon nitride. As a result, it is small, for example 2keV Soft X-rays of energy can be extracted from the soft X-ray tube 3. In the region near the window 33 in the ionization chamber 2, the correlation coefficient force when the soft X-rays react with the base gas increases as the energy of the soft X-rays decreases. Therefore, when the window member 33a has such a configuration, the ion density can be further increased using soft X-rays having lower energy.

 It should be noted that the ionization apparatus 1 of the present embodiment has the following advantages over the conventional ionization apparatus using the corona discharge that is emitted from the radioisotope. In other words, by using soft X-rays for ionization, it is easy to handle without the need for administrator installation or limited use space, which is safer than when radioisotopes are used. Also, compared to corona discharge, the ion current 1 is more stable than the corona discharge. In addition to not giving noise to the electrical system placed in the rear stage or the vicinity of the ionizer 1, impurities accompanying discharge breakdown of the electrode are generated. I do n’t live. In addition, since the irradiation energy can be increased as compared with ionization of the base gas using vacuum ultraviolet light (VUV) or the like, more ions can be generated with fewer restrictions on the base gas species.

 [0055] In addition, in the method using corona discharge, the voltage of the discharge electrode is extremely high, so that an electric field is formed in the ionization reaction space, and the behavior of ions is affected by the electric field, so that It is difficult to control the flow. In order to prevent the influence of this electric field, there is also a method in which base gas ions are generated by corona discharge in another space separated to some extent and the base gas ions are sent to the ionization chamber. However, in this case, unless the base gas ions are diffused quickly in the ionization chamber, it is difficult to ionize the sample molecules uniformly and quickly in the ionization chamber, and the ionization efficiency is also lowered. End up.

 [0056] On the other hand, according to the ionization apparatus 1 of the present embodiment using soft X-rays, the electric field formed in the ionization chamber 2 (electric field for separating ions and electrons) can be reduced, and It can operate without an electric field. In addition, since the radiation range of soft X-rays is wide, the base gas can be efficiently ionized over a wide range. Therefore, a uniform reaction can be performed quickly in the ionization chamber 2 and ionization efficiency can be improved.

[0057] Further, as described above, the amount of electrons from the electron source 31 of the soft X-ray tube 3 and the acceleration voltage thereof are adjusted. As a result, the amount of base gas ions generated can be easily adjusted. Therefore, if the base gas ions are larger than the sample molecular ions, the sample molecular ions are repelled and diffused by the space charge effect with the base gas ions, or the ionization chamber 2 In addition, it is possible to reduce the influence of sample molecule ions being charged up in a space provided in the subsequent stage.

[0058] (Modification)

 Next, various modifications of the ionization apparatus 1 according to the above embodiment will be described.

FIG. 4 is a cross-sectional view showing a configuration of an ionization apparatus la according to a first modification of the above embodiment. The main body 21 of the ionization apparatus la includes an introduction pipe 25 as an inlet for introducing sample molecules and a base gas, instead of the introduction port 22 (see FIG. 1) of the above embodiment. The introduction tube 25 is a cylindrical member extending in a predetermined axial direction (X-axis direction), and is provided so as to penetrate the flat portion 5b of the electrode 5 in the X-axis direction. Therefore, the central axis direction of the introduction tube 25 intersects the soft X-ray emission axis direction (Z-axis direction) of the soft X-ray tube 3 (perpendicular in this modification). In this modification, the central axis of the introduction tube 25 coincides with the central axis A of the discharge port 23 and is orthogonal to the soft X-ray emission axis B of the soft X-ray tube 3.

FIG. 5 is a cross-sectional view showing a configuration of an ionization apparatus lb according to a second modification of the above embodiment. The ionizer lb includes an electrode 5a as the second electrode in place of the electrode 5 of the above embodiment. The electrode 5 a is provided on the end side opposite to the electrode 4 in a predetermined axial direction (X-axis direction) of the ionization chamber 2, and faces the electrode 4. The electrode 5a is provided so as to cover the opening 21b on the end side opposite to the electrode 4 of the ionization chamber 2. In this modification, the opening 21b serves as an inlet 26 for base gas and sample molecules, and the electrode 5a has an opening 51 through which the base gas and sample molecules pass. Specifically, the electrode 5a has a mesh portion 52 in which a net-like (mesh-like) member is formed in a planar shape, and a large number of gaps formed in the mesh portion 52 constitute an opening 51. Yes. Further, the electrode 5a is short-circuited with the target electrode 32b and has an electrode portion 53 for effectively forming an electric field inside the ionization chamber 2.

[0062] As in the modifications shown in Figs. 4 and 5, the base gas or sample molecule inlet is provided on the opposite side of the outlet 23 to be coaxial with the outlet 23, and the direction of the central axis of the inlet is Soft X-ray tube 3 soft X-ray You may make it cross | intersect (it orthogonally crosses in this modification) with an output axis direction. When the introduction tube 25 is passed through the electrode 5 as in the modification shown in FIG. 4, a part of the introduction tube 25 (the portion in contact with the electrode 5 and the portion in contact with the electrode 5) are considered from the viewpoint of electric field formation and pressure resistance in the ionization chamber 2. It is preferable that the vicinity) or the whole is made of an insulating material.

6 to 8 are cross-sectional views showing configurations of ionization apparatuses lc to le according to third to fifth modifications of the above embodiment. The ionizers lc˜; le according to these modifications are characterized by the shape of the first electrode.

 [0064] The ionization apparatus lc shown in FIG. 6 includes an electrode 4b instead of the electrode 4 (see FIG. 1) in the configuration of the ionization apparatus 1 according to the above embodiment. The electrode 4b is provided at the outlet 23 of the ionization chamber 2, and has an opening 44 through which sample molecular ions pass. The inner surface (end surface) of the opening 44 is continuous with the inner surface of the discharge port 23 (that is, the inner surface of the ionization chamber 2 along the predetermined axial direction (X-axis direction)). Specifically, the openings 44 are formed in the same shape as the discharge ports 23 when viewed from a predetermined axial direction (X-axis direction), and are arranged so that their edges overlap each other. Further, the electrode 4b of this modification example does not have a mesh portion, unlike the electrode 4 of the above-described embodiment (see FIG. 1). Therefore, the electrode 4b is completely exposed without covering the discharge port 23.

 Further, the ionization apparatus Id shown in FIG. 7 includes an electrode 4b instead of the electrode 4 in the configuration of the first modification shown in FIG. Further, the ionizer le shown in FIG. 8 includes an electrode 4b in place of the electrode 4 in the configuration of the second modified example shown in FIG. The shape of the electrode 4b shown in FIGS. 7 and 8 is the same as that of the electrode 4b of the ionizer lc shown in FIG.

 [0066] As shown in Figs. 6 to 8, the first electrode (electrode 4b) does not have a mesh portion, and the inner surface of the opening 44 is continuous with the inner surface of the discharge port 23 (that is, the electrode 4b does not cover the discharge port 23), the surface of the electrode 4b on the ionization chamber 2 side is not exposed to the soft X-ray tube 3 side, so that soft X-rays are not irradiated to the electrode 4b. Thus, the emission of secondary electrons from the electrode 4b can be effectively suppressed.

FIG. 9 is a cross-sectional view showing a configuration of an ionization apparatus If according to a sixth modification of the above embodiment. The ionizer If includes an intermediate electrode 71 and 72 in addition to the electrodes 4 and 5. The intermediate electrodes 71 and 72 are arranged side by side between the electrodes 4 and 5, and the electrodes 4 and 5 In cooperation with, an electric field is formed inside the ionization chamber 2. Therefore, a potential gradient is applied to each electrode so that the potential gradually increases in the order of the electrode 4, the intermediate electrode 71, the intermediate electrode 72, and the electrode 5). For example, in FIG. 9, lead terminal 43 of electrode 4, lead terminal 73 of intermediate electrode 71, lead terminal 74 of intermediate electrode 72, and lead terminal 50 of electrode 5 are connected to bleeder circuit board 75 (detachable). The power supply voltage is divided and supplied to these lead terminals. In order to facilitate the formation of an electric field in which the formed ions move from the vicinity of the window 33 of the soft X-ray tube 3 to the central axis side of the ionization chamber 2, the intermediate electrodes 71 and 72 It is preferable to be provided only on the side opposite to the side to be attached. In this modification, the end portions 71a and 72a of the intermediate electrodes 71 and 72 on the ionization chamber 2 side do not protrude from the inner surface of the ionization chamber 2 along the predetermined axial direction (X-axis direction). Located in the same plane as the inner surface. As a result, for the same reason as the electrode 4b of the third to fifth modifications described above, the soft X-rays are prevented from being irradiated to the intermediate electrodes 71 and 72, and the generation of secondary electrons is suppressed. ing.

[0068] As in this modification, the intermediate electrodes 71 and 72 are further provided between the first electrode 4 and the second electrode 5, so that the electric field between the electrode 4 and the electrode 5 is more effective. Can be formed. In this modification, the force S is provided with two intermediate electrodes, and the number of intermediate electrodes may be one or three or more.

 FIG. 10 (a) is a cross-sectional view showing a configuration of an ionization device lg according to a seventh modification of the above embodiment. FIG. 10 (b) is a cross-sectional view showing a cross section along the line XX of the ionizer lg shown in FIG. 10 (a). FIGS. 10 (a) and (b) show only the main part of the ionizer lg.

 In the ionization device lg according to this modification, the inner surfaces of the ionization chamber 2 excluding the surfaces of the soft X-ray tube 3 and the electrode 5 are all made of an insulating member. Specifically, the ionizer lg includes intermediate electrodes 71 and 72 as in the ionizer If shown in FIG. However, the intermediate electrodes 71 and 72 of this modification are completely covered by the main body 21 made of an insulating member at the ends 71a and 72a on the ionization chamber 2 side.

[0071] Further, the ionizer lg includes an electrode 4c as a first electrode. The electrode 4c is provided at the outlet 23 of the ionization chamber 2 and has an opening 45 through which sample molecular ions pass. The inner surface (end surface) of the opening 45 is located outside the inner surface of the discharge port 23 with respect to the central axis A of the discharge port 23. That is, the opening 45 is formed wider than the discharge port 23 when viewed from a predetermined axial direction (X-axis direction), and the edges of the discharge port 23 are arranged so as to be located inside the opening 45. Yes. In other words, the side surface around the discharge port 23 of the main body 21 is exposed in the opening 45 of the electrode 4c. Further, the electrode 4c of this modification also has no mesh portion, like the electrode 4b shown in FIGS. For this reason, the electrode 4c completely exposes the discharge port 23 without covering it.

[0072] As in the present modification, the end portions 71a, 72a of the intermediate electrodes 71, 72 are covered with an insulating member (main body portion 21), and the inner surface of the opening 45 is located outside the inner surface of the discharge port 23. Thus, since soft X-rays are hardly irradiated to the intermediate electrodes 71 and 72 and the electrode 4c, generation of secondary electrons can be more effectively suppressed. In this way, if all the inner surfaces of the ionization chamber 2 except for the surfaces of the soft X-ray tube 3 and the electrode 5 are made of insulating members, secondary electrons are emitted in the ionization chamber 2 by soft X-ray irradiation. Since it can be effectively suppressed, when generating a positive sample molecular ion, the neutralization (neutralization) of the sample molecular ion is reduced and the ion density is further increased by the force S.

 FIG. 11 (a) is a cross-sectional view showing a configuration of an ionization apparatus lh according to an eighth modification of the above embodiment. FIG. 11 (b) is a cross-sectional view showing a cross section taken along line XI-XI of the ionizer lh shown in FIG. 11 (a). Figures 11 (a) and (b) show only the main part of the ionizer lh. The ionization apparatus lh according to this modification includes intermediate electrodes 71 and 72 as in the ionization apparatus If shown in FIG. However, as a difference from the ionization apparatus If of FIG. 9, the intermediate electrodes 71 and 72 of this modification have end portions 71a and 72a on the ionization chamber 2 side protruding from the inner surface of the ionization chamber 2. As a result, soft X-rays are irradiated to the intermediate electrodes 71 and 72, and many secondary electrons are emitted. Therefore, when generating negative sample molecular ions, it is possible to help generate ions and increase the ion density.

[0074] FIG. 12 is a cross-sectional view showing a main part of the configuration of an ionization apparatus li according to a ninth modification of the embodiment. The seal mechanism 6a of the ionizer li includes a seal member 64 in place of the seal member 60 of the above embodiment. The seal member 64 is a member provided around the soft X-ray source 3 to keep the ionization chamber 2 airtight. The sealing member 64 of this modification is made of glass fiber. And at least one of ceramic fibers and is wound around the vacuum vessel 30 of the soft X-ray tube 3. The seal member 64 is pressed against the vacuum vessel 30 by being clamped from above and below by the support member 61 and the annular member 63. As a result, the gap between the soft X-ray tube inlet 24 and the soft X-ray tube 3 is sealed.

 FIG. 13 is a cross-sectional view showing a main part of the configuration of an ionization apparatus lj according to a tenth modification of the above embodiment. The ionizer lj includes a seal mechanism 6b instead of the seal mechanism 6 (see FIG. 1) of the above embodiment. The seal mechanism 6b has a seal member 65. The seal member 65 of this modification is configured to include at least one of glass fiber and ceramic fiber, like the seal member 64 shown in FIG. The seal member 65 is disposed in the gap between the vacuum container 30 of the soft X-ray tube 3 and the soft X-ray tube inlet 24.

 [0076] Further, the seal mechanism 6b is fixed to the main body 21 and has a cylindrical member 66 communicating with the soft X-ray tube inlet 24, and a cylinder that is screwed into the member 66 from the inside and is movable in the vertical direction. And the insulating spacer 68 disposed between the seal member 65 and the member 67. The seal member 65 is sandwiched between the flange portion of the vacuum vessel 30 and the insulating spacer 68, and is clamped from above by the insulating spacer 68 and pressed against the vacuum vessel 30. As a result, the gap between the soft X-ray tube inlet 24 and the soft X-ray tube 3 is sealed.

 FIG. 14 is a cross-sectional view showing a main part of the configuration of an ionization apparatus lk according to an eleventh modification of the above embodiment. The ionizer lk includes a seal mechanism 6c instead of the seal mechanism 6 (see FIG. 1) of the above embodiment. The seal mechanism 6c has a seal member 69. The seal member 69 of this modification is an annular member containing a metal or a carbon-based material, for example, an annular member in which a conductor is applied to the surface with a heat-resistant polymer such as polyimide or carbon or CNT is mixed inside. It is a member and is arranged between the electrode of the window 33 of the soft X-ray tube 3 (in this modification, the flange portion of the target electrode 32b) and the ionization chamber 2.

[0078] The seal mechanism 6c includes a member 66, a moving member 67, and an insulating spacer 68 in the same manner as the seal mechanism 6b (see FIG. 13). Then, the flange portion of the vacuum vessel 30 is pressed downward by the insulating spacer 68, whereby the seal member 69 is crushed and the gap between the soft X-ray tube inlet 24 and the soft X-ray tube 3 is sealed. At the same time, the target electrode 32 b and the electrode 5 are short-circuited via the seal member 69. [0079] Although not shown, a metal plate may be airtightly fixed to the ceiling portion of the ionization chamber 2 with which the seal member 69 contacts by brazing or the like, and the seal member 69 may be disposed on the metal plate. Further, it is preferable that the metal plate and the electrode 5 are brought into contact with each other to be electrically conducted.

 [0080] As shown in the ninth and tenth modifications (FIGS. 12 and 13), the seal member may be configured to include at least one of glass fiber and ceramic fiber. Alternatively, as shown in the eleventh modification (FIG. 14), the seal member may be a member containing a metal or a carbon-based material. By either of these, even under a high temperature environment of, for example, around 300 ° C, the gas release from the seal member can be extremely reduced and the seal member does not thermally decompose, so that the ionization chamber 2 is kept airtight. It can maintain suitably. Also, the soft X-ray source 3 can be easily replaced.

 FIG. 15 is a cross-sectional view showing the main parts of the configuration of an ionization apparatus lm according to a twelfth modification of the above embodiment. In this modification, the soft X-ray source 3 is arranged slightly apart from the ionization chamber 2 so that the window 33 of the soft X-ray source 3 is in a predetermined axial direction (X-axis direction) in the ionization chamber 2. Retreats against the inner surface 27 along. In other words, the window 33 is located outside the inner surface 27 of the ionization chamber 2. A space 28 is formed between the window 33 and the ionization chamber 2, and the conductive base 9 is disposed in the space 28. The conductive base 9 has a cylindrical shape extending in the soft X-ray irradiation axis direction (Z-axis direction), and soft X-rays pass through the inside thereof. One end of the conductive base 9 is in contact with the target electrode 32b of the soft X-ray source 3, and the other end of the conductive base 9 is disposed on the ionization chamber 2 side and is in contact with the electrode 5. By this conductive base 9, the space 28 is suitably maintained and the target electrode 32b and the electrode 5 are short-circuited.

 As described above, the window portion 33 of the soft X-ray source 3 may be retracted from the inner surface 27 of the ionization chamber 2. As a result, the soft X-ray irradiation range in the ionization chamber 2 is limited, and the generation of secondary electrons in the ionization chamber 2 or in a space provided at the subsequent stage can be reduced. Further, by providing the conductive base 9, the target electrode 32b and the electrode 5 can be easily short-circuited.

FIG. 16 is a cross-sectional view showing the main parts of the configuration of an ionization apparatus In according to a thirteenth modification of the embodiment. The ionizer In includes a window 11 in addition to the configuration of the ionizer lm shown in FIG. This window portion 11 includes a window portion 33 of the soft X-ray tube 3 and an ionization chamber 2. And transmits soft X-rays from the soft X-ray tube 3 to the ionization chamber 2. The window portion 11 includes a window material 1 la that transmits soft X-rays, and a conductive flange portion ib that is provided around the window material 1 la and supports the window material 1 la. The window portion 11 of this modification is provided so as to close the other end side of the conductive base 9, and the flange portion ib is in contact with the other end of the conductive base 9. Further, the flange portion l ib is also in contact with the electrode 5, and a short circuit between the target electrode 32 b and the electrode 5 is achieved. The window material 11a may be made of the same material (aluminum, titanium, beryllium, silicon, silicon nitride, etc.) as the window material 33a of the soft X-ray tube 3.

 [0084] As shown in FIG. 15, when the soft X-ray tube 3 is moved backward to provide the space 28, the electric field due to the electrode 5 and the target electrode 32b is not effectively formed and is generated in the vicinity of the window 33. It becomes difficult to move the ion to electrode 4. In addition, sample molecules and the like tend to stay in the space 28, and the change in the amount of sample molecules over time is reflected in the change in ion density. On the other hand, according to the configuration of the ionization device In shown in FIG. 16, the window 11 prevents the sample molecules and the like from staying in the space 28 generated by the retraction of the soft X-ray tube 3, and the flange portion. The electric field of the ionization chamber 2 can be effectively formed by the l ib and the electrode 5. In order to prevent sample molecules and the like from entering the space 28, it is preferable that the flange portion ib and the conductive base 9 be hermetically sealed. Further, as shown in FIG. 17, an annular seal member 69 containing a metal or a carbon-based material may be disposed between the flange portion l ib and the ionization chamber 2. Note that the sealing material 69 may be a material that allows soft X-rays to pass through but does not allow gas or charged particles to pass therethrough, and may also serve as both a window material and a sealing material.

 FIG. 18 is a cross-sectional view showing a main part of the configuration of an ionization apparatus lp according to a fourteenth modification of the above embodiment. An ionizer lp according to this modification includes a collimator 13 in place of the conductive base 9 in the configuration of the ionizer 1 m shown in FIG.

That is, in this modification, the window portion 33 of the soft X-ray source 3 is retreated with respect to the inner surface 27 along the predetermined axial direction (X-axis direction) in the ionization chamber 2. A collimator (X-ray collimator) 13 is arranged in a space formed between the window 33 and the ionization chamber 2. The collimator 13 has a plurality of through holes 13a extending in the soft X-ray irradiation axis direction (Z-axis direction), and the soft X-rays pass through the through holes 13a. In addition, one end of the collimator 13 is in contact with the target electrode 32b of the soft X-ray source 3, and the other end of the collimator 13 is disposed on the ionization chamber 2 side to be charged. It is in contact with pole 5. This collimator 13 improves the directivity of soft X-rays.

 As described above, by providing the collimator 13 between the window 33 and the ionization chamber 2, the soft X-ray irradiation range in the ionization chamber 2 is further limited, and the inside of the ionization chamber 2 or the interior thereof. Generation of secondary electrons in the space provided in the subsequent stage can be more effectively reduced. Compared to the configurations shown in FIGS. 16 and 17, even if the distance between the window 33 and the ionization chamber 2 is made narrower, the irradiation range can be limited to the same level or higher, so that the ionization efficiency is high! The area near the window 33 can be used effectively. In particular, when using low-energy soft X-rays, the region closer to the window 33 has a higher correlation coefficient (reaction coefficient) with the base gas, so the collimator 13 can be used to connect the window 33 and the ionization chamber 2 to each other. It is preferable to narrow the interval.

 [0088] The collimator 13 has a structure in which through-holes 13a are uniformly formed in the thickness direction on a substrate made of a material that absorbs X-rays (for example, a metal such as W, Ta, Mo, or Pb glass). Use your body. As the cross-sectional shape of the through hole 13a, various shapes such as a circle, a triangle, a quadrangle, and a hexagon can be applied. Further, it is preferable that the through hole 13a has a large depth ratio (aspect ratio) with respect to the aperture having a large aperture ratio. The shape of the collimator 13 may be a one-dimensional slit shape in which the length of the ion flow direction (X-axis direction) is shortened.

 [0089] When the constituent material of the collimator 13 is conductive, the target electrode 32b and the electrode 5 can be short-circuited by directly installing the collimator 13 between the window 33 and the ionization chamber 2, and further, the ionization chamber The above-described electric field 2 can be effectively formed. In addition, when the constituent material of the collimator 13 is insulative, by forming a conductive film on the inside, the edge, or the back surface of the through-hole 13a, the same effect as in the case of the conductive material force can be obtained. Obtainable. If the diameter of the through-hole 13a is relatively large and sample molecules or base gas may enter, a window material 15 is installed on the end surface of the collimator 13 on the ionization chamber 2 side as shown in the ionizer lp 'shown in FIG. May be. The window material 15 may be made of the same material (aluminum, titanium, beryllium, silicon, silicon nitride, etc.) as the window material 33a of the soft X-ray tube 3.

FIG. 20 is a cross-sectional view showing a configuration of an ionization apparatus lq according to a fifteenth modification of the above embodiment. The soft X-ray tube 3a included in the ionizer lq includes an electron source 34 instead of the electron source 31 of the above embodiment. The electron source 34 is disposed on one end side in the longitudinal direction of the vacuum vessel 30 (the side away from the ionization chamber 2), and is illustrated for converging and accelerating the cold cathode 34a. Shina! /, Including electrodes.

 [0091] Thus, by using the cold cathode 34a as the electron source, the temperature rise of the electron source can be suppressed lower than when the filament 31a (see FIG. 1) is used as the electron source. The temperature inside the ionization chamber 2 can be prevented from rising, and the ionization reaction can be generated stably. Further, for example, when this ionization apparatus lq is applied to an ion mobility meter, the temperature rise in the drift chamber following the ionization chamber 2 can be suppressed, and the measurement accuracy can be improved.

 FIG. 21 is a cross-sectional view showing a configuration of an ionization apparatus lr according to a sixteenth modification of the above embodiment. The soft X-ray tube 3b included in the ionizer lr includes a deflecting unit 35 in addition to the configuration of the soft X-ray tube 3 of the above embodiment. The deflecting unit 35 is a scanning electrode for scanning electrons emitted from the electron source 31, and is provided inside the vacuum container 30 along the soft X-ray emission axis B. When the deflecting unit 35 scans the electrons emitted toward the target unit 32, the target unit 32 is extremely short! /, And the time width (temporal pulsed) soft X-rays are generated. Generated. Therefore, in the ionization chamber 2, temporally sampled molecular ions can be easily obtained. This eliminates the need for a gate shirt for emitting sample molecular ions in the form of temporal noise, and simplifies the structure. It should be noted that by applying an acceleration voltage to the electron source 31 in a pulsed manner, it is also possible to obtain a Nordic soft X-ray.

 Example 2

 FIG. 22 is a cross-sectional view showing a configuration of a mass spectrometer (MS) 100a according to the second embodiment of the present invention. The mass analyzer 100a is a device for analyzing sample molecules such as organic substances introduced from the outside, and includes an ionizer ls, a quadrupole 101, a deflector 103, a detector 105, and a housing 107. The casing 107 is a container capable of maintaining a vacuum atmosphere, and includes a sample analysis chamber 107a and adjustment chambers 107b and 107c.

[0094] Skis 109b and 109c are installed in the adjustment chambers 107b and 107c, respectively. The skis 109b and 109c are arranged along the central axis A of the ionization chamber 2 of the ionizer Is, allowing sample molecule ions to pass through and maintaining the differential pressure between the ionization chamber 2 and the sample analysis chamber 107a. To do. An electron lens forming electrode 11 lb is installed at the rear stage of the ski 109b, and an electron lens forming electrode 11lc is installed at the rear stage of the ski 109c. The sample analysis chamber 107a has a quadrupole 101, a deflector 103, and a detector. 105 is arranged.

 [0095] The quadrupole 101 is an element for selectively extracting only sample molecular ions having a specific mass / charge ratio out of sample molecular ions emitted from the ionization chamber 2 of the ionizer Is. . The quadrupole 101 is formed by arranging a pair of rod-shaped electrodes juxtaposed and a pair of rod-shaped electrodes so that their juxtaposition directions intersect each other. When a voltage satisfying a certain condition (a voltage obtained by concatenating a DC voltage and an AC voltage) is applied to each rod-shaped electrode, only sample molecular ions having a mass / charge ratio corresponding to the voltage condition are Pass between rod-shaped electrodes. That is, by adjusting the voltage condition, only sample molecule ions having a desired mass / charge ratio can be passed and selectively extracted.

 The deflector 103 is a component for changing the traveling direction of the sample molecular ions that have passed through the quadrupole 101 to the detector 105, and is arranged at the subsequent stage of the quadrupole 101. The detector 105 is a component for detecting sample molecular ions that have passed through the quadrupole 101, and generates a current corresponding to the number of sample molecular ions.

 [0097] In addition to the configuration of the ionization apparatus 1 of Example 1 shown in FIG. 1, the ionization apparatus Is further includes a heat retaining container 17 for keeping the ionization chamber 2 at a high temperature. The heat insulating container 17 has a heat insulating member 81 on the wall material and accommodates the main body 21. The soft X-ray tube 3 is passed through an opening provided in the heat insulating container 17, and the electron source 31 is located outside the heat insulating container 17. A heat source (not shown) is provided inside the heat retaining container 17.

 The mass analyzer 100a of the present embodiment includes an ionizer Is including the configuration of the ionizer 1 (see FIG. 1) of the first embodiment. As a result, sample molecules can be ionized at a high density, so that mass spectrometry can be performed with higher accuracy.

Further, the ionization device Is of the present embodiment includes a heat retaining container 17, and the electron source 31 is located outside the heat retaining container 17. In the ionizer, the inside of the ionization chamber 2 may be heated to promote ionization, prevent clustering, or prevent contamination by sample molecules. In such a case, it is preferable to arrange the electron source 31 of the soft X-ray tube 3 outside the heat insulating container 17 as in the present embodiment. When the electron source 31 includes a filament, disposing the filament outside the heat insulating container 17 can suppress heat consumption and disconnection, and extend the life of the soft X-ray tube 3. Even when an electron source other than a filament is used, The electron source can be placed in a temperature environment suitable for the work.

 Example 3

 FIG. 23 is a sectional view showing a configuration of an ion mobility spectrometer (IMS) 100b according to the third embodiment of the present invention. The ion mobility meter 100b is a device that measures the difference in moving speed by ionizing sample molecules such as gas components with the ionization device 1 and then flying the sample molecule ions in a gas with a force of electric field. .

 [0101] The ion mobility meter 100b of the present embodiment includes the ionizer 1, the drift tube 120, and the heat insulating container 19. Since the configuration of the ionization apparatus 1 is the same as that of the first embodiment described above, detailed description thereof is omitted.

 [0102] The inside of the drift tube 120 is hollow and forms a drift chamber 121. Drift chamber

 Reference numeral 121 denotes a region extending in a predetermined axial direction (X-axis direction), one end side of which communicates with the ionization chamber 2 and sample molecules ionized in the ionization chamber 2 move in the longitudinal direction. The drift tube 120 includes a plurality of ring-shaped electrodes 123 and a plurality of ring-shaped electrical insulators 125, and the electrodes 123 and the electrical insulators 125 are alternately stacked. In other words, the electrical insulator 125 is disposed between the adjacent electrodes 123, and the electrodes 123 are electrically insulated by the electrical insulator 125. The plurality of electrodes 123 form an electric field in the drift chamber 121 for moving the ionized sample molecules.

 [0103] On one end side of the drift tube 120, a gate electrode 127 as a gate shutter is provided. As the gate electrode 127, for example, a Bradbury-Nielsen shutter can be used. The gate electrode 127 allows sample molecular ions to pass through when the applied potential changes, and includes a pair of electrodes. When the potential difference between the pair of electrodes becomes zero, the sample molecular ions are allowed to pass. Further, when a predetermined value greater than the potential difference SO is reached, the passage of sample molecular ions is prohibited. Therefore, by supplying a pulsed signal to the gate electrode 127 and setting the potential difference between the pair of electrodes to 0 for a predetermined time, the sample molecular ions pass through the gate electrode 127 for the predetermined time. It becomes.

A conductive substrate 129 is provided on the other end side of the drift tube 120. The substrate 129 includes a collector electrode 131 for collecting sample molecular ions and a drift gas introduced into the drift chamber 121. A drift gas introduction pipe 133 is arranged.

 The electrodes 4 and 5, the gate electrode 127, the plurality of electrodes 123, and the collector electrode 131 of the ionizer 1 are electrically connected in this order by a voltage dividing resistor (not shown). The voltage dividing resistor is a thin film resistor formed on the bleeder circuit board 135, and is electrically connected to the electrodes 4 and 5, the gate electrode 127, the plurality of electrodes 123, and the collector electrode 131 through lead terminals. Is done. As a result, an electric field is formed from the ionization chamber 2 to the drift chamber 121. By this electric field, the sample molecular ions move from the ionization chamber 2 to the drift chamber 121, and move in the drift chamber 121 toward the collecting electrode 131.

 [0106] The operation of the ion mobility meter 100b is as follows. The sample molecule ions generated in the ionization chamber 2 are introduced into the drift chamber 121 in a time-north manner by applying a pulsed voltage to the gate electrode 127 to change the potential. The time-null ion group introduced into the drift chamber 121 moves with its own time delay due to the influence of the molecules of the drift gas introduced from the drift gas introduction tube 133. The collector electrode 131 is reached along a substantially uniform electric field formed in 121. The ion group that has reached the collector electrode 131 is output as a pulsed electric signal. Based on the electric signal, the arrival time (flight time) from the gate electrode 127 to the collector electrode 131 and the sample that has reached the collector electrode 131 The amount of molecular ions is detected. The ion mobility can be obtained from the arrival time, and the sample molecule can be identified. In addition, the sample molecule can be quantified from the integrated value or peak value of the response waveform of the electrical signal.

 [0107] Note that the heat retaining container 19 is a container for keeping the ionization chamber 2 of the ionization apparatus 1 and the drift chamber 121 of the drift tube 120 at a high temperature. The heat insulating container 19 has a heat insulating member 83 on its wall material, and accommodates the main body 21 of the ionization apparatus 1 and the drift tube 120. The soft X-ray tube 3 of the ionization apparatus 1 is passed through an opening provided in the heat insulating container 19, and the electron source 31 is located outside the heat insulating container 19. Inside the heat retaining container 19, a heat source (not shown) is provided.

[0108] The ion mobility meter 100b of the present example includes the ionization apparatus 1 of the first example. As a result, sample molecules can be ionized at a high density, so that sample molecules can be identified and quantitatively analyzed with higher accuracy. Example 4

 FIG. 24 is a cross-sectional view showing a configuration of an electron capture detector 100c according to the fourth embodiment of the present invention. The electron capture detector 100c of the present embodiment includes an ionizer 1, a discharge pipe 140, and a heat insulating container 19. The configuration of the ionizer 1 is the same as the configuration of the first embodiment described above, and thus detailed description thereof is omitted. The heat insulation container 19 covers the ionization chamber 2 of the ionization apparatus 1, and the discharge pipe 140 communicates with the discharge port 23 of the ionization chamber 2 and penetrates the heat insulation container 19 to discharge gas and sample.

 [0110] The operation of the electron capture detector 100c is as follows. The electron capture detector 100c measures the ion current accompanying ionization with the mesh electrode 4 between the electrodes 4 and 5 of the ionizer 1. First, the current value when a carrier gas such as nitrogen, argon, or He that is difficult to form anions is measured as the base current. Next, it becomes easy to become anions! / When a sample such as an explosive or halogen compound is introduced together with a carrier gas, the ionized electrons are captured and anionized. Since these anions have a lower mobility than electrons, the residence time in ionization apparatus 1 is increased. As a result, the probability of colliding with cations that are also formed becomes extremely large, and the anion and cation lose their charge from each other, reducing the base current. The decrease value of the base current is proportional to the sample concentration. In addition, as in the electron capture detector 100d shown in FIG. 25, the portion corresponding to the discharge port 23 of the electrode 4 is opened, and current is detected by the collection electrode 141 provided so as to face the discharge port 23. It's okay.

 [0111] The electron capture detectors 100c and 100d of the present embodiment include the ionization apparatus 1 of the first embodiment. As a result, sample molecules can be ionized at a high density, so that quantitative analysis of sample molecules can be performed with higher accuracy.

 Example 5

 FIG. 26 is a cross-sectional view showing a configuration of a charged particle measuring apparatus for chromatograph 100e according to a fifth embodiment of the present invention. The charged particle measuring apparatus 100e for chromatograph of the present embodiment has almost the same structure as the electron capture detector 100c of the embodiment 4, and the portion corresponding to the discharge port 23 of the electrode 4b becomes an opening.

[0113] The operation of this charged particle measuring apparatus for chromatograph 100e is as follows. Illustrated The sample eluted from the non-chromatographic column is sprayed with, for example, nitrogen gas to form fine droplet particles, and flows into the ionizer 1. Nitrogen ions positively charged by the ionizer 1 collide with the particles, and the particles are positively charged. By transporting these charged particles from the discharge tube 140 to an ion separator and collector (not shown) and measuring the current value, a signal proportional to the sample concentration can be obtained. The portion corresponding to the discharge port 23 of the electrode 4b is not limited to the opening, but may be a coarse mesh member.

[0114] The charged particle measuring apparatus 100e for chromatographs of the present example is the same as the ionization apparatus of Example 1.

With one. As a result, sample molecules can be ionized at a high density, so that quantitative analysis of sample molecules can be performed with higher accuracy.

[0115] The ionization apparatus, mass analyzer, ion mobility meter, electron capture detector, and chromatographic charged particle measurement apparatus according to the present invention are not limited to the above-described embodiments and modifications. Various modifications are possible. For example, in the above embodiment, the soft X-ray emission axis direction of the soft X-ray tube 3 is the force S perpendicular to the predetermined axial direction of the ionization chamber 2, and the soft X-ray emission axis direction of the soft X-ray source is the ionization chamber. The predetermined axis direction may be crossed obliquely. Similarly, the direction of the central axis of the inlet 22 may be obliquely intersected with the soft X-ray emission axis direction, which is not limited to the form orthogonal to the soft X-ray emission axis direction.

 In addition, as shown in FIG. 27, a soft X-ray tube 3c having a tube axis extending in a predetermined axial direction A is added so that the window 33 of the soft X-ray tube 3c also serves as a termination electrode. May be. Alternatively, as shown in FIG. 28, a pedestal 29 made of an insulating member is provided between the electrode 5a made of a mesh-like member and the target electrode 32b of the soft X-ray tube 3c, and the soft X-rays are transmitted through the electrode 5a. A soft X-ray tube 3c may be attached so as to be irradiated.

 Furthermore, as shown in FIG. 29, a control unit 10 that controls the potentials of the target electrode 32b and the electrodes 4 and 5 may be provided. At this time, when the insulating material 20 is provided between the target electrode 32b and the electrode 5, the control unit 10 may control the target electrode 32b and the electrode 5 to the same potential.

[0118] Further, the target electrode 32b and the electrode 5 are not limited to the same potential, and different potentials may be applied thereto. In this case, as shown in FIG. 30, as an insulating member between the target electrode 32b and the electrode 5, an insulating collimator 14 having the same shape as the collimator 13 of the fourteenth modified example of FIG. May be used.

Industrial applicability

 The ionization apparatus according to the present invention can be suitably used as an ionization chamber using soft X-rays, and is particularly suitable for mass spectrometers, ion mobility meters, electron capture detectors, and charged particle measurement apparatuses for chromatographs using the ionization apparatus. Applicable.

Claims

The scope of the claims  [1] An ionization chamber that extends in a predetermined axial direction and ionizes sample molecules, a first introduction port that introduces sample molecules into the ionization chamber, and the first introduction port are provided in common or independently. A second introduction port for introducing a base gas into the ionization chamber, and a discharge port formed on one end side of the ionization chamber in the predetermined axial direction and for discharging sample molecules ionized in the ionization chamber; A main body having  An electron source, a target unit that receives electrons from the electron source to generate soft X-rays, a vacuum container that houses the electron source and the target unit, and a soft X-ray emitted from the target unit And a soft X-ray source that emits soft X-rays transmitted through the ionization chamber,  A first electrode provided at the outlet and having an opening through which ionized sample molecules pass;  A second electrode provided on an end side of the ionization chamber opposite to the first electrode in the predetermined axial direction;  With  The soft X-ray emission axis direction of the soft X-ray source intersects the predetermined axis direction, and the angle force formed by the surface of the second electrode facing the ionization chamber and the predetermined axis direction is 70 degrees or more. 120 degrees or less  An ionizer characterized by that. 2. The ionization apparatus according to claim 1, wherein the angle force formed by the surface of the second electrode facing the ionization chamber and the predetermined axial direction is not less than 0 degrees and not more than 120 degrees. [3] The ionization apparatus according to [1] or [2], wherein the target unit includes a target electrode that is short-circuited with the second electrode. [4] The ionization apparatus according to [3], wherein the target electrode and the second electrode are in contact with each other. [5] It further includes a control unit capable of controlling a potential applied to the target electrode disposed in the target unit, and the target electrode and the second electrode, The control unit is configured so that the target electrode and the second electrode have the same potential. The ionization device according to claim 1, wherein the ionization device is controlled. [6] The ionization device according to any one of [5] to [5], including at least one of window material silicon and silicon nitride that transmits soft X-rays in the window portion. [7] The inner surface of the ionization chamber excluding the respective surfaces of the soft X spring source and the second electrode is made of an insulating member; Optimizer.  [8] An intermediate electrode is further provided between the first electrode and the second electrode,  8. The ionization apparatus according to claim 7, wherein an end of the intermediate electrode on the ionization chamber side is covered with the insulating member. [9] The inner surface of the opening of the first electrode is continuous with the inner surface of the discharge port of the ionization chamber, or outside the inner surface of the discharge port with respect to the central axis of the discharge port. The ionization device according to claim 7 or 8, wherein [10] The intermediate electrode further comprising an intermediate electrode between the first electrode and the second electrode, the intermediate electrode protruding from the inner surface of the soft X-ray source, the second electrode, and the ionization chamber The ionization apparatus according to any one of claims 1 to 6, wherein an inner surface of the ionization chamber excluding a surface of each end portion on the ionization chamber side is made of an insulating material. [11] The window portion of the soft X-ray source is disposed so as to recede with respect to an inner surface along the predetermined axial direction in the ionization chamber,  10. The apparatus according to claim 1, further comprising another window portion that is provided between the window portion and the ionization chamber, transmits the soft X-ray, and is short-circuited with the window portion. The ionizer according to any one of the above. [12] The window portion of the soft X-ray source is disposed so as to recede with respect to the inner surface along the predetermined axial direction in the ionization chamber,  The ionization apparatus according to any one of claims 8 to 11, wherein the collimator is further provided between the window portion and the ionization chamber. [13] It further comprises a seal member that keeps the ionization chamber airtight, 13. The seal member according to claim 1, wherein the seal member is provided around the soft X-ray source and includes at least one of glass fiber and ceramic fiber. The ionizer described. [14] It further comprises a sealing member for keeping the ionization chamber airtight,  The seal member is an annular member containing a metal or a carbon-based material provided between the X-ray source and the ionization chamber. Ionizer. [15] The apparatus further comprises a heat retaining container that houses the main body and holds the main body at high temperature,  15. The electron source according to claim 1, wherein the electron source is located outside the heat insulation container. V, the ionizer according to any one of the above. 16. The ionization apparatus according to any one of claims 1 to 8, wherein the soft X-ray source has a cold cathode as the electron source. [17] The ionization apparatus according to any one of [1] to [16], wherein the soft X-ray source further includes a deflecting unit that deflects the electrons emitted from the electron source. . [18] The ionization apparatus according to any one of [18] to [17], further including a second soft X-ray source having a tube axis extending in the predetermined axial direction. [19] A mass analyzer comprising the ionization device according to any one of [1] to [18].  [20] An ion mobility meter comprising the ionization device according to any one of [1] to [18].  [21] An electron capture detector comprising the ionization device according to any one of [1] to [18].  [22] A charged particle measuring apparatus for guchimatograph comprising the ionization apparatus according to any one of claims 1 to 18;