A device for holding at least one filament and a mass spectrometer

Abstract

The present invention relates to a holding device (1) for at least one filament, comprising at least one filament receptacle (2a, 2b) for accommodating at least one filament. The holding device (1) is designed for removably attaching, in particular by clamping, the at least one filament receptacle (2a, 2b) to a vessel (7) of an ionizer. The present invention also relates to a mass analyzer comprising: an ionizer having a vessel (7) in which an ionization space for ionizing gas is formed; at least one holding device (1) designed for removably attaching, in particular by clamping, the at least one filament receptacle (2a, 2b) to the vessel (7); and a vacuum housing to which the holding device (1), in particular a base body (4) of the holding device (1), is removably coupled.

Description

[Technical field]

[0001] The present invention relates to a holding device for at least one filament, comprising at least one filament receiving section for receiving (and holding) at least one filament, and to a mass spectrometer having at least one such holding device. [Background technology]

[0002] Filaments (glow wires) are used in ionizers to ionize gases and can be used, for example, in mass spectrometers for trace analysis. In electron ionization, the filament (glow wire) is heated to a high temperature to produce an electron beam that, by the thermoelectric effect, bombards and ionizes the gas to be ionized.

[0003] To replace the filament of such electron ionizers, it is generally necessary to remove the entire ionizer (i.e., the inlet or inlet system, the vessel with the ionization volume, and the extraction optics) from the mass spectrometer to replace the filament. This is a very time-consuming operation and requires breaking the vacuum. However, in certain applications of mass spectrometry, such as process monitoring, the high time consumption required for filament replacement is difficult to tolerate. Summary of the Invention [Problem to be solved by the invention]

[0004] It is an object of the present invention to provide a device for holding at least one filament, which allows for a rapid exchange of (at least) one filament, and a mass spectrometer. [Means for solving the problem]

[0005] This object is achieved by a holding device of the type mentioned at the beginning, which is designed for releasable attachment of a filament receptacle to a vessel of an ionization device, in particular for attachment in the manner of a clamp, and which is typically installed in an installation position in which the filament feeds or can feed an electron beam into an ionization space formed in the vessel.

[0006] According to the invention, it is proposed that the holding device or filament accommodation for at least one filament is mechanically decoupled from the vessel of the ionizer in which the ionization space is formed. The filament or filaments are therefore not directly mounted on the vessel or ionizer, but are arranged on or attached to separate filament accommodations which are removably fixed to the vessel. Each filament accommodation typically has only one filament, which is arranged (clamped) in a predefined installation position on the vessel. The filament or filament accommodations are typically clamped to the vessel for removably mounting, i.e. the holding device is designed to exert a clamping force on the filament or filament accommodations in the installation position in order to press the filament accommodation against the vessel.

[0007] In the installed position, the filament receiving part rests on the vessel or the housing of the ionizer, and in order to prevent the filament receiving part from slipping in the installed position, the filament receiving part may have one or more protrusions for engaging with one or more recesses, e.g. in the form of grooves, on the vessel of the ionizer in the installed position, or vice versa.

[0008] In one embodiment, the holding device comprises a base body coupled to at least one filament receiving portion via at least one coupling element, the base body typically being designed to be removably fixed to the (vacuum) housing of the mass spectrometer, such that the filament receiving portion or portions can be accessed during filament replacement by removing the base body or the entire holding device from the mass spectrometer housing.

[0009] The base body can have a flange or form a flange that is typically aligned perpendicularly to the main or central axis of the vessel or ionizer and that is flange-connected, typically screwed, to the housing of the mass spectrometer. Through an opening in the housing that is free when the base body is removed, at least one filament receptacle, which is likewise connected to the base body via a connecting element, can be removed from the ionizer. If the base body is attached to a defined installation position on the housing of the mass spectrometer, for example by flange connection or screw fastening, the filament receptacle is also held in a defined installation position relative to the vessel with the aid of the connecting element and is thus clearly positioned relative to the vessel. In particular, the connecting element can serve to generate a clamping or pressing force on the filament receptacle that is arranged in the holding position or to transmit this force to the filament receptacle.

[0010] In one development, the connecting element is designed as an elastic element, in particular a leaf spring, in which case the connecting element is deflected from its basic position in the installation position and exerts a force on the filament receiving part, so that the connecting element itself is used to apply a clamping force to at least one filament receiving part.

[0011] As another development, the connecting element is designed rigid and the pretensioning element engages in it in order to apply a clamping force to the filament-receiving part, in which case the connecting element itself does not apply a clamping force to the filament-receiving part but serves the function of transmitting the clamping force transmitted from the (mechanical) pretensioning element to the rigid connecting element.

[0012] As a further development, the base body has a linear guide for guiding the connecting element, which can form, for example, a sliding feedthrough. The connecting element can be displaced along the linear guide relative to the base body. In this case, the connecting element and thus the filament receiving part are held in the installed position against the action of a pretensioning force, which usually acts parallel along the direction along which the connecting element can be displaced. When inserting the holder into the mass spectrometer, the connecting element is typically displaced from a basic position in which the pretensioning element exerts no pretensioning force on the connecting element against the action of a pretensioning force when the filament receiving part abuts against the vessel. In this way, in the installed state of the holding device, i.e. after the base body of the holding device is fixed to the housing of the mass spectrometer, the pretensioning element exerts a clamping force on the filament receiving part. In order to releasably clamp the filament receiving part to the vessel, the holding device can also have a sliding feedthrough instead of a linear guide.

[0013] In another embodiment, the connecting element forms a pivotable arm that is connected to the base body via a rotary joint. When inserting the holding device into the vacuum housing, the connecting element typically pivots or deflects from the basic position about the axis of rotation against the action of a pretensioning force as soon as the filament receiving part abuts against the container. In the installation position, i.e. after the base body of the holding device is fixed on the vacuum housing, the filament receiving part is pressed against the action of a pretensioning force against the container. The pivotable arm can in particular form a double-armed lever, on the first lever arm of which the filament receiving part is rigidly fixed. The pretensioning element typically acts on the second lever arm.

[0014] In a further development, the pretensioning element is preferably designed as a spring element, which is connected on the one hand to the base body and on the other hand to the connecting element. In the above case where the base body has a linear guide for the connecting element, the spring element can be, for example, a compression spring. In this case, when the holder is introduced into the ionizer, the filament receiving part is displaced together with the connecting element against the action of the compression spring, so that the filament receiving part exerts a clamping force on the container in its installation position. In the above case where the filament receiving part is attached to a connecting element in the form of a pivotable arm functioning as a double-armed lever, the spring element can be connected at one end to a second lever arm and at the other end to the base body.

[0015] The holding device preferably has two coupling elements in the form of pivotable arms, each connected to the base body via a rotary joint. In this case, a separate filament accommodation is fixed to each of the two pivotable arms. This embodiment is particularly advantageous when two (possibly three or more) filament accommodations are removably attached or fixedly clamped to opposite sides of the container. The use of two separate rotary joints and the attachment of the two pivotable arms to the same base body has been found to be advantageous for providing a clamping force, as will be explained in more detail below.

[0016] In a further development, the pretensioning element is designed to pivot the two pivot arms in opposite directions, i.e. in opposite rotational directions, around the respective rotary joints in order to fix in a clamping manner the two filament receptacles attached to the pivot arms on the two opposite sides of the container. For this purpose, the pretensioning element typically acts on two first lever arms of the pivotable arms or on two second lever arms of the pivotable arms in order to pivot towards each other or away from each other. In order to pivot the two pivotable arms in the manner of a pair of pliers (symmetrically) relative to the container, the pretensioning element engages with the respective (first or second) lever arms of the pivotable arms at the same distance from the respective rotation axis. The holding device, more precisely the connecting element and the filament receptacle, can in particular be arranged with mirror symmetry with respect to a plane or axis of symmetry. The plane or axis of symmetry intersects the central axis of the container.

[0017] The advantage of clamping the vessel from two sides (symmetrically) in this way is that shear forces that could displace the vessel's main axis are prevented. The optimal position of the vessel's main axis is maintained in this way, since it is not necessary to remove the vessel or the ionizer for filament replacement. The inlet or inlet opening for feeding the gas to be ionized into the ionization space, and the outlet for the ionized gas, are typically formed along the vessel's main axis. The vessel typically has a substantially radially symmetrical, i.e. cylindrical, basic shape with the cylindrical axis forming the vessel's main axis.

[0018] In a further embodiment, the pretensioning element is designed to be rigid, in particular rod-shaped, guided in a guide track, in particular a linear guide, of the base body and has a free end with an abutment surface for abutting against the container. In this case, the pretensioning element moves along the guide track when introducing the holding device into the housing as soon as the abutment surface comes into abutment against the container. The movement along the guide track has the effect that the pretensioning element acts on the connecting element in order to transmit a clamping force to the connecting element. In this case, it has proven to be advantageous if the pretensioning element is guided in a linear guide so that it can be displaced linearly. The displacement direction of the pretensioning element is preferably oriented perpendicular to the central axis of the container.

[0019] In a further development, the pretensioning element has a guide element which engages with the two pivotable arms. Typically, in this case the entire pretensioning element moves along a guide track and a guide element, for example in the form of a bolt, pin or the like, is coupled to a respective lever arm of the two pivotable arms and pivots the respective lever arm about a respective axis of rotation to apply a clamping force to the filament receiving part or receptacles in the installation position of the holding device. The coupling of the guide element to the two pivot arms can be carried out, for example, by means of an elongated hole provided in the first or second lever arm of the pivot arms. Needless to say, the guide element can also be coupled to the pivotable arms in other ways.

[0020] Another aspect of the invention relates to a mass spectrometer, comprising a vessel in which an ionization space for ionizing a gas is formed, at least one holding device designed as described above for removably mounting, in particular clamping, at least one filament receiving part to the vessel, and a vacuum housing to which the holding device, in particular the base body of the holding device, is removably coupled. The base body of the holding device typically has a flange portion and is removably coupled to the vacuum housing in its installed position, for example by a screw coupling. In this way, the holding device or its base body is accessible to an operator outside the vacuum housing for replacing the filament.

[0021] If the holding device has two (possibly more than two) filament accommodations for holding two (possibly more than two) filaments, the ionizer can be operated redundantly. Replacement of the filaments or removal of the holding device is only necessary if both filaments fail. However, the mass spectrometer can also have two or more holding devices, each fixed to the vacuum housing via separate base bodies or flanges, arranged perpendicular to one another or opposite one another with respect to the vessel. In this case, as soon as one of the filaments breaks, the respective holding device can be released from the vacuum housing. However, in this case, at least two independent accesses or openings are required in the vacuum housing to ensure redundancy.

[0022] Through an access or opening in the vacuum housing, the holding device together with the filament accommodation(s) can be removed from the vacuum housing and the filament replaced, without the need to remove the entire vessel or ionizer from the vacuum housing and place it back in the vacuum housing after replacing the filament, which is particularly convenient when the ionizer or its vessel / housing are directly coupled to or screwed onto an ion transfer component, such as a transfer quadrupole.

[0023] When the holding device is removed from the vacuum housing, the vacuum must be released. To ensure a fast exchange of the filament, the vacuum housing must be vented with an inert gas, e.g. (dry) nitrogen or a noble gas. In this way, the pumping time after the filament exchange can be reduced, since the drainage of the water adhering to the inner walls of the vacuum device during the other venting is the most time-consuming step of the entire pumping process.

[0024] In one embodiment of the mass spectrometer, the rigidly designed pretensioning element of the holding device rests its abutment surface on the vessel in the installation position. As explained in detail in connection with the holding device acting like pliers, in this case the pretensioning element comes into abutment with the vessel when the holding device is inserted into the vacuum housing and presses the two filament receiving parts fixed on the pivotable arms against either side of the vessel or clamps them to the vessel in relation to the vessel's main axis. To achieve this, the flange part of the base body is typically oriented perpendicular to the vessel's main or central axis or the ionizer's main axis.

[0025] Further features and advantages of the invention emerge from the following description of embodiments of the invention, with reference to the drawings showing the details which are material to the invention, and from the claims. Each of the individual features can be implemented individually or collectively in any combination in a variant of the invention. The embodiments are shown in the schematic drawings and explained in the following specification. [Brief description of the drawings]

[0026] [Figure 1] FIG. 1 is a schematic diagram of a holding device having two filament housings. [Diagram 2] FIG. 2 is a schematic diagram of a mass spectrometer having the holding device of FIG. 1 for clamping or fixing two filament housings on the vessel of an ionizer. [Figure 3a] 2 is a schematic diagram of the holding device of FIG. 1 and a container to which two filament receiving portions are fixed in a clamping manner. [Figure 3b] 2 is a schematic diagram of the holding device of FIG. 1 and a container to which two filament receiving portions are fixed in a clamping manner. [Figure 3c] 2 is a schematic diagram of the holding device of FIG. 1 and a container to which two filament receiving portions are fixed in a clamping manner. [Figure 4a] FIG. 2 is a schematic diagram of a holding device for clamping a filament receiving portion to a container. [Figure 4b] FIG. 2 is a schematic diagram of a holding device for clamping a filament receiving portion to a container. [Figure 4c] FIG. 2 is a schematic diagram of a holding device for clamping a filament receiving portion to a container. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] In the following description of the drawings, the same reference numbers are used for identical or functionally identical components.

[0028] Figure 1 shows diagrammatically a holding device 1 with two filament receiving parts 2a, 2b for receiving (and for holding) respective filaments 3a, 3b (see Figure 2), not shown. The first and second filament receiving parts 2a, 2b are in each case connected to a base body 4 of the holding device 1 by means of first and second connecting elements 5a, 5b. In the example shown in Figure 1, each of the two connecting elements is designed in the form of a rigid pivotable arm 5a, 5b. Each of the pivotable arms 5a, 5b is connected to the base body 4 via its own rotary joint 6a, 6b.

[0029] Figure 2 shows the two filament receptacles 2a, 2b in the installation position of the holding device 1 of a mass spectrometer 9. As can be seen from Figure 2, in the installation position of the holding device 1, the two filament receptacles 2a, 2b are placed on two opposite sides of a vessel 7 of an ionization device 8 which constitutes part of the mass spectrometer 9. When installing the holding device 1, the two filament receptacles 2a, 2b are attached or fixed in a clamping manner to the vessel 7 by a pliers movement of two pivotable arms 5a, 5b.

[0030] In the illustrated example, the container 7 has a generally cylindrical outer surface against which the filament housings 2a, 2b are brought into abutment, and the pivotable arms 5a, 5b apply a clamping force to the filament housings 2a, 2b, as will be described in more detail below in connection with Figures 3a-3c.

[0031] The ionizer 8 of the mass analyzer 9 shown in Fig. 2 has an inlet or inlet system 10 for feeding a gas 11 to be analyzed into an ionization space 12 formed in a vessel 7 of the ionizer 8. As can also be seen in Fig. 2, a first filament 3a generates an electron beam 13 which is fed into the ionization space 12 through a side opening of the vessel 7 and serves to generate, by electron impact ionization, an ionized gas 14 to be analyzed.

[0032] The mass spectrometer 9 also comprises an extraction device 15 in the form of an electrode arrangement for extracting the ionized gas 12 from the ionization space 10 and accelerating and, if necessary, focusing the ionized gas 12 towards a transfer quadrupole 16 before it is analyzed by mass spectrometry with a detector 17, for example in the form of a time-of-flight detector. The transfer quadrupole 16, in addition to transferring the ionized gas 14, can also perform the function for mass separation or for mass selection. Needless to say, the mass spectrometer 9 shown in FIG. 2 should be understood as an example and can be designed in other ways. For example, the mass spectrometer 9 can have other types of detectors 17, other types of ion transfer devices, etc.

[0033] The mass spectrometer 9 shown in Figure 2 also includes a vacuum housing 18 in the form of a stainless steel housing in which the ionizer 8 and vessel 7 are fixed. The ionizer 8 or vessel 7 may in particular be screwed to other components of the mass spectrometer 9, such as the extractor 15 or the moving quadrupole 16. The components or stages within the vacuum housing 18 are differentially pumped by vacuum pumps (not shown). The interior of the vacuum housing 18 of the mass spectrometer 9 is not readily accessible to an operator from the outside.

[0034] In order nevertheless to be able to quickly exchange the filaments 3a, 3b, the base body 4 of the holding device 1 is fixed in its installed position in the mass spectrometer 1 to the vacuum housing 18 of the mass spectrometer 9 by a removable connection, typically by screwing. In the illustrated example, the plate-shaped part 4a of the base body 4 is arranged outside the vacuum housing 18 and is flanged or screwed to the vacuum housing 18. The part 4b of the base body 4 protruding from the plate-shaped part 4a extends into the interior of the vacuum housing 18 of the mass spectrometer 9 in the installed position of the holding device 1.

[0035] Therefore, in order to replace the two filaments 3a, 3b in the mass analyzer 9 shown in Figure 2, it is not necessary to remove the ionization device 8, particularly the container 7, from the vacuum housing 18 of the mass analyzer 9; it is sufficient to remove the externally accessible part 4a of the base body 4 from the vacuum housing 18 and the holding device 1 from the vacuum housing 18, and the clamping of the two filament accommodating parts 2a, 2b is released.

[0036] For replacement of the filaments 2a, 2b, it is necessary to break the vacuum in the vacuum housing 18. In order to avoid moisture getting on the components arranged therein or on the inside of the vacuum housing 18, the interior of the vacuum housing 18 is vented or purged with an inert gas, for example (dry) nitrogen. In this way, the pumping time during the subsequent re-evacuation of the vacuum housing 18 can be significantly reduced.

[0037] In order to reposition the holding device 1 in the vacuum housing 18 after replacement of the filaments 2a, 2b, the protruding part 4a of the base body 4 together with the filament receiving part 2a, which is connected to the base body 4 via two pivotable arms 5a, 5b, is introduced into the vacuum housing 18 along the Z direction of the XYZ coordinate system shown in Figure 2, specifically through an access or opening in the vacuum housing 18 located in the Z direction on the main or central axis M of the ionization device 8. Thus, in the mass analyzer 9 shown in Figure 2, the plate-shaped part 4a of the base body 4 extends parallel to the XY plane, which corresponds to the plane of the drawing.

[0038] In order to press the two filament-receiving parts 2a, 2b against the outer or circumferential surface of the container 7 and to fix or clamp them in position relative to the container 7, the holding device 1 shown in Figures 1 and 3a to 3c has a rigidly designed rod-shaped pretensioning element 20. The rod-shaped pretensioning element 20 extends along an axis of symmetry S of the holding device 1 which runs perpendicular to the plate-shaped part 4a of the base body 4 and which corresponds to the Z direction at the installation position of the holding device 1 in the vacuum housing 18.

[0039] The rod-shaped pretensioning element 20 has an abutment surface 20a (see FIG. 1) which is pressed against the container 7, more precisely against its outer surface, when the holding device 1 is inserted into the vacuum housing 18. The rod-shaped pretensioning element 20 is displaced in a linear guide 21 (rail) formed in the protruding part 4b of the base body 4 along an axis of symmetry S which corresponds to the Z direction of the installation position of the holding device 1. During linear displacement of the pretensioning element 20 in the Z direction, a guide element 22 (a bolt in the illustrated example) attached to the pretensioning element 20 and protruding laterally out of an elongated hole formed in the protruding part 4a of the base body 4 is displaced in the direction of the plate-shaped part 4a of the base body 4.

[0040] The guide element 22 in the form of a projecting bolt engages in the two pivotable arms 5a, 5b, more precisely in two elongated holes 23a, 23b in a first lever arm of each of the two pivotable arms 5a, 5b, which in the illustrated example are designed as double-armed levers. In this way, the linear movement of the pretensioning element 20, and thus of the guide element 22, is converted into an opposite pivoting movement of the two pivotable arms 5a, 5b, which move in opposite directions in the manner of pliers and are adapted to exert a clamping force on the two filament receiving parts 2a, 2b which, in the installed position of the holding device 1, abut on two opposite sides of the container 7, as shown in FIG. The distance between the guide element 22 of the rod-shaped pretensioning element 20 and the free end of the pretensioning element 20 on which the abutment surface 20a is formed corresponds to the length of the pivotable arms 5a, 5b, so that the filament receiving portions 2a, 2b in the installed position can be brought into lateral abutment with the container 7, thereby allowing a moderate clamping force to be exerted on the filament receiving portions 2a, 2b.

[0041] As can be seen in FIG. 3c, each of the filament receiving sections 2a, 2b has a concave (spherical) curved abutment surface 24a, 24b formed on the protrusion of the filament receiving section 2a, 2b protruding in the direction of the container 7. In the installed position, the protrusion of the respective filament receiving section 2a, 2b engages in an annular groove (not shown) provided on the outer circumferential surface of the container 7. In the installed position, the spherically curved abutment surface 24a, 24b rests on a similarly spherically curved bottom surface of an annular circumferential groove formed in the disk-shaped circular base plate of the container 7. The engagement of the protrusion of the filament receiving section 2a, 2b in the groove on the container 7 creates a lateral guide and prevents undesired movements of the respective filament receiving section 2a, 2b in the installed position in the direction of the central axis M of the container 7.

[0042] The vessel 7 is designed only cylindrically for the sake of simplicity, but can have basically any geometric shape. In particular, it is not necessary for the vessel 7 to have a continuous circumferential outer surface with only two openings for the passage of the respective electron beams 13. In the simplest case, the vessel 7 is formed from two end plates connected to each other via a spacer. In this case, or in general, the ionization space 12 can form its own (optionally heatable) vessel, which is arranged in the vessel 7 in which the filament receptacles 2a, 2b are fixed in a clamping manner. In this case, the respective filament receptacles 2a, 2b come with their abutment surfaces 24a, 24b to abut, for example, against a groove on the periphery of one or possibly both end plates and are clamped by the above-mentioned pliers mechanism in the installation position of the holding device 1.

[0043] In the case of the holding device 1 shown in Figures 1 and 3a to 3c, the two filament receptacles 2a, 2b are clamped on opposite sides of the container 7, said clamping being performed symmetrically with respect to an axis of symmetry S of the holding device 1 which runs perpendicularly to and intersects the central axis M of the container 7. In this way, shear forces which could otherwise displace the central axis M of the container 7 can be avoided when applying the clamping force. Since it is not necessary to remove the ionization device 8 and thus the container 7 for a filament exchange, the optimized position or arrangement of the container 7 is maintained when exchanging the filament.

[0044] The holding device 1 shown in Figures 1 and 3a to 3c is typically only removed from the mass spectrometer 9 if both filaments 3a, 3b are defective and need to be replaced. A single functional filament 3a, 3b is sufficient for operation of the ionizer 8, i.e. during operation of the ionizer 8, typically only one filament 3a, 3b is heated by a resistive heater (not shown) known per se to generate the electron beam 13.

[0045] While the holding device 1 shown in Figures 1 and 3a to 3c is adapted to hold two filaments 3a, 3b on a common base body 4, Figures 4a to 4c show three holding devices 1, each designed to hold only one single filament 3a on the filament receiving section 2a. In case of removably fixing two filaments 3a, 3b to the container 7, the mass analyzer 9 can have two holding devices 1 designed as in Figures 4a to 4c. The base bodies 4 of the two holding devices 1 can be mounted in two separate openings or accesses of the vacuum housing 18, generally facing each other, to prevent the occurrence of shear forces (see above).

[0046] The holding device 1 shown in Fig. 4a has a connecting element for connecting the base body 4 to the filament receiving part 2a, which is designed as an elastic element, more precisely as a leaf spring 5a. In the installed position of the holding device 1, the leaf spring 5a presses the filament receiving part 2a against the container 7 in order to clamp the filament receiving part 2a to the container 7.

[0047] The holding device 1 shown in Fig. 4b, like the holding device 1 shown in Fig. 1, has a connecting element in the form of a pivotable arm 5a, which is connected to the base body 4 via a rotary joint. The pivotable arm 5a forms a double-arm lever, to one of which the filament receiving part 2a is rigidly fixed and to the other of which a pretensioning element 20' in the form of a tension spring is engaged, which generates a clamping force for pressing the filament receiving part 2a against the container 7.

[0048] In the holding device 1 shown in FIG. 4c, in order to exert a clamping force on the filament receiving part 2a in the installed position of the holding device 1 and releasably clamp it against the container 7, the base body 4 has a linear guide 25, or more precisely a sliding feedthrough, for a connecting element 5a of rigid design which is displaced relative to the base body 4 against the force of a pretensioning element 20′ in the form of an elastic element.

[0049] The above-described holding device 1 allows the filaments 3a, 3b to be exchanged without removing the ionizer 8 or the vessel 7 from the vacuum housing 18 of the mass analyzer 1. This, on the one hand, makes it very easy to exchange the filaments 3a, 3b, and, on the other hand, avoids the need to reposition or align the vessel 7 or the ionizer 8 when it is reinserted into the vacuum housing 18 after exchanging the filaments 3a, 3b. Needless to say, the holding device 1 shown in Figures 4A to 4C can also be used for mass analyzers 9 or ionizers 8 with only one filament 3a. [Explanation of symbols]

[0050] 1 Holding device 2a, 2b Filament storage section 3a, 3b filaments 7 containers 8. Ionizer

Claims

1. A holding device (1) for at least one filament (3a, 3b) used in a mass spectrometer, comprising at least one filament accommodating portion (2a, 2b) for accommodating at least one filament (3a, 3b), The holding device (1) is designed for removable mounting, in particular for clamping, of at least one filament receptacle (2a, 2b) to a vessel (7) of an ionization device (8), and further comprises a base body (4) connected to the at least one filament receptacle (2a, 2b) via at least one connecting element (5a, 5b), the base body (4) having a flange aligned perpendicular to a main or central axis of the vessel (7) of the ionization device (8) for screwing to a housing of a mass spectrometer.

2. 2. The holding device according to claim 1, wherein the connecting element is designed as a resilient element, in particular as a leaf spring (5a).

3. 2. The holding device according to claim 1, wherein the connecting elements (5a, 5b) are designed to be rigid and a pretensioning element (20, 20') engages the connecting elements (5a, 5b) to apply a clamping force to the filament receiving portion (2a, 2b).

4. 4. The holding device according to claim 3, wherein the base body (4) has a linear guide (25) for guiding the connecting element (5a).

5. 4. A holding device according to claim 3, wherein the connecting elements form pivotable arms (5a, 5b) connected to the base body (4) via rotary joints (6a, 6b).

6. 6. The holding device according to claim 3, wherein the pretensioning element is preferably designed as a spring element (20'), which is connected on the one hand to the base body (4) and on the other hand to the connecting element (5a).

7. 7. A holding device according to claim 5 or 6, comprising two connecting elements in the form of pivotable arms (5a, 5b), each connected to the base body (4) via a rotary joint (6a, 6b).

8. 8. A holding device according to claim 7, wherein the pretensioning element (20) is designed to pivot the two pivotable arms (5a, 5b) in opposite directions about each of the rotary joints (6a, 6b) in order to fix in a clamping manner the two filament receiving parts (2a, 2b) attached to the pivotable arms (5a, 5b) on two opposite sides of the container (7).

9. 9. A holding device according to any one of claims 3 to 5, 7 and 8, wherein the pretensioning element (20) is designed to be rigid, in particular rod-shaped, and is guided in a guide track, in particular a straight guide (21), of the base body (4), the pretensioning element (20) having a free end with an abutment surface (20a) for abutting against the container (7).

10. 10. The holding device according to claim 9, wherein the pretensioning element (20) has a guide element (22) which engages in the two pivotable arms (5a, 5b).

11. A mass spectrometer (9), an ionization device (8) having a container (7) in which an ionization space (12) for ionizing a gas (11) is formed; A holding device (1) according to any one of claims 3 to 10, which is designed for removably attaching, in particular for clamping, at least one filament receiving portion (2a, 2b) to the container (7); the holding device (1) comprises a vacuum housing (18) to which, in particular, the base body (4) of the holding device (1) is removably coupled; A mass spectrometer comprising:

12. 12. Mass spectrometer according to claim 11, wherein the rigidly designed pretensioning element (20) of the holding device (1) rests on the container (7) with a resting surface (20a).

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