EP2860752B1 - Electrode device with pre- and/or postfilters and manufacturing method therefor, as well as a mass spectrometer with such an electrode device - Google Patents

Description

The invention relates to a method according to claim 1 for producing an electrode device, in particular a multipole, for use in a mass spectrometer, wherein the electrode device comprises at least one main filter and at least one pre and / or post filter. The invention further relates to such an electrode device according to claim 6, as well as a mass spectrometer with such a multi-pole electrode device according to claim 11.

Multipolar electrode arrangements for the characterization of chemical compounds are known in the art, for example from the German patent 944900 known. Such multipole mass filters operate without a magnetic field. A quadrupole, for example, comprises four metal rods which serve as electrodes and are arranged on a circle with radius R ₀ . The voltage across the electrodes is composed of a high-frequency AC voltage and a DC voltage, wherein the respectively opposite pairs of the electrodes have a phase-shifted by 180 ° high-frequency voltage. The ions to be separated are shot as a fine ion beam in the longitudinal direction of the electrodes in the field. Due to the applied AC and DC voltages, the ions are moved on defined trajectories through the mass filter. Outside stable boundary conditions, the ions collide with the electrodes, neutralizing them. As a result, these neutralized ions no longer reach the detector.

The applied voltage to the electrodes is linear to the detected ion mass, which is why for the passage through the mass range, ie for setting the desired mass to be detected, a proportional change of AC voltage and DC voltage is made. A change in the resolution can be effected by changing the voltage conditions. In particular, a stability diagram plays a role, which is calculated according to the differential equations of Mathieu. A good overview of how a quadrupole works, including an explanation of the stability diagram, can be found in Miller & Denton, 1986, "The Quadrupole Mass Filter: Basic Operating Concepts", Journal of Chemical Education, Volume 63, no. 7, pages 617-623 ,

When measuring with a multipole in particular the alignment of the electrodes is important to each other, as this must be carried out with high precision. A manufacturing process for this high-precision alignment is, for example DE 10 2004 054 835 A1 known. Nevertheless, the problem remains that edge regions of the electrodes represent more unstable zones for ions and thus contribute to defocusing. This effect has been studied in particular by Dawson, 1971, "Fringing Fields In The Quadrupole Mass Filter", International Journal of Mass Spectrometry and Ion Physics, Volume 6, pages 33-44 , Dawson undertook simulations based on the findings of Brubaker, who proposed for the first time pre- and postfilter. Pre- and post-filters act as a pre- and post-stage of the main filter, by applying only a weak AC voltage. The field does not start or stop abruptly for the ions, but the ions are slowly led into or out of the field. Therefore, the ions achieve a higher stability and thus a better focus. The pre and post filters work similarly to lenses.

In the implementation of pre- and post-filters in practical application, the high-precision alignment of the electrodes to one another (eg prefilter to main filter) must be taken into consideration, since even small inaccuracies lead to field disturbances can. In DE 22 15 763 For example, the implementation of pre and post filters is shown. However, a great effort must be made here at high cost for the highly accurate alignment of the filter to each other.

US 2004/0 245 460 A1 shows the production of modules that can be assembled into a multipole. The individual modules each have a carrier element, an insulator and one or more electrodes. The electrodes can be divided into several segments, which can be charged differently with voltage. The electrodes are also processed so that they have, for example, a hyperbolic surface. The prior art according to US 2004/0 245 460 A1 has the disadvantage that when separating into the individual segments, the cutting tool comes into contact with the insulator, whereby the separating tool and / or the insulator is damaged.

The object of the invention is thus to improve the production method for electrode devices with pre and / or post filters and to provide a resulting electrode device.

The invention solves this problem by providing a manufacturing method for an electrode device with pre- and / or post-filter and provides an electrode device with pre- and / or post-filter as a product. The electrode device in this case comprises a plurality of electrode arrangements which can be joined together to form the electrode device. An electrode assembly has one or more electrodes. The electrodes are each made of an electrode blank, which preferably has metal. Particularly preferably, the electrode blank consists of solid material. The electrode blank is preferably rod-shaped and in particular has a round cross-section. The blank may be formed, for example, as a round rod. From this electrode blank, the main filter, one or more prefilters and / or one or more post-filters are produced. The manufacturing process comprises several steps, which are repeated until the intended Number of pre and / or post filters is reached. Alternatively, the electrode blank may also have, for example, a trapezoidal or rectangular cross section and thus serve, for example, for ion guidance or for ion transfer.

The term pre- and post-filter includes that the pre- and post-filters may also be lenses or lens-like, as they preferentially focus the ions to enter them with a collimated beam into the main filter. In this case, in contrast to the main filter, no filtering takes place in the true sense, ie. little or no ions are neutralized. Whether the pre- and / or post filters only have a focusing effect or also neutralize ions also depends on whether and how the pre- and / or post filters are supplied with DC voltage. Both possibilities can be realized with the present invention.

To produce an electrode arrangement, each electrode blank is connected to holding means. For example, for an electrode device as a quadrupole, the electrode device comprises four electrode blanks, the electrode blanks being divided into a plurality of electrode arrays. For example, For example, an electrode assembly each comprises two electrode blanks. Alternatively, one of the electrode assemblies comprises only one electrode blank and the other electrode assembly comprises three electrode blanks. Also, the electrode device may be e.g. composed of four individual electrode assemblies, each having an electrode blank.

Preferably, the holding means are designed such that they can hold the electrode rod assemblies as a device. They can then also be referred to as a holding device.

According to the invention, the holding means comprise at least one carrier element, each blank of the electrode being connected to the one or more carrier elements is connected. In particular, the attachment takes place indirectly by interposition of one or more insulators. By the holding means, in particular the carrier elements, the electrode assemblies can be connected together and assembled to form an electrode device.

The holding means are thus formed as a carrier element or carrier elements and at least one insulator.

In a further step, each blank electrode is separated into two sections, wherein the sections are axially spaced apart by means of a gap. The gap thus extends through the entire electrode blank and electrically separates the two sections from each other, whereby the individual sections can be applied independently of each other with voltage. The portions are held in a constant relative position or in a constant relative position to each other during and after the separation by the holding means. Each of the sections is used as a filter along with the sections of the other electrode blanks in the finished electrode device. For example, several first sections form a prefilter and several second sections form a main filter. A "set" of filter sections (eg, a first and a second section for pre- and main filters) is thus made from a single electrode blank, the holding means holding the sections at each time in position relative to each other so that the relative position between the Sections not changed. This method has the advantage that the separation between a pre- and post-filter and the main filter takes place only when the two sections are firmly connected by the holding means. A shift of the sections against each other and a re-alignment thus eliminated and saves additional effort. The exact positioning of the electrodes increases the analytical accuracy.

This separation step, ie the separation of the electrode blank into two sections, is performed as often as it corresponds to the intended number of pre and / or post filters. The number of electrode blanks corresponds to the number of desired electrodes. If e.g. a prefilter and a post filter are provided, the electrode blanks are separated twice into two sections, so that each electrode blank a total of three sections arise, each axially spaced from each other with a gap and of the holding means in a constant relative position held each other. The total of three sections are then used together with the sections of the other electrode blanks as pre-filter, main filter and post-filter. The multiple electrode arrays are joined together in a further step by connecting the holding means to the electrode device.

According to the invention, the holding means comprise at least one carrier element, in particular a single carrier element, and insulator means comprising at least one insulator. The insulator or insulators, ie non-conductive material, preferably comprise quartz or ceramic, wherein in the case where the insulator means consist entirely of quartz, the material of the electrode blank is preferably made of (for example marketed under the trademark "Invar") Alloy with the material number 1.3912 (German steel key) is. In the case that the insulator means are made of ceramic, the metal of the electrode blank is preferably an iron-nickel-cobalt-based fused alloy, for example, as the alloy (sold under the trade mark "Vacon") with the material number 1.3981 (German steel key). or as the under the name Vacon 11 or Vacon 11 T available alloy.

The insulator means are connected according to the invention with the electrode blank, wherein this compound can be made detachable or non-detachable. Preferably, the insulator or the insulators are applied with an adhesive, by screws or by soldering to the electrode blank. However, it is For example, it is also possible to sinter the insulator means, in particular, if they are made of ceramic, onto the electrode blank. The metal of the electrode and the insulators preferably have a similar coefficient of thermal expansion, so that a permanent connection between metal and insulator is ensured.

The carrier element is connected according to the invention with at least one insulator of the insulator means. If the insulator means comprise a plurality of insulators, the carrier element is connected to at least one of these insulators. If the insulator means comprise only one insulator, the carrier element is connected to exactly this insulator. The carrier element, which preferably has a semicircular arc-like shape in cross-section, is preferably made of the same material as the electrode blank. The carrier element and the insulator or the insulators are preferably detachably or non-detachably connected to one another. Preferably, the connection is created by gluing by means of an adhesive, by soldering, by screwing or by sintering. Particularly preferably, the insulator is connected by gluing to the carrier element and thus produces a permanent connection.

According to the invention, at least one insulator of the insulator means is connected to both sections and thereby holds the sections in the same relative position to one another. If the insulator means comprise a plurality of insulators, then at least one of the insulators and / or the carrier element is connected to both sections. If the insulator means comprise only one insulator, this one insulator and / or the carrier element is connected to both sections. The insulator acts in an insulating manner between the electrode blank and the carrier element, so that the blank electrode and the carrier element are e.g. can also consist of the same material.

For example, the insulator means may comprise a plurality of short insulators, a long insulator, or a combination of these two solutions. Here is the insulator or the insulators are designed or positioned such that there is a stable connection between the two sections. For example, a long insulator may be positioned on the electrode blank so that it is connected to both sections. The carrier element is then positioned on the insulator.

According to the invention, the insulator means, in particular an insulator of the insulator means, hold the sections in the same relative position relative to each other. The electrode blank and / or the insulator is then provided with a recess. The recess or the recesses are arranged such that they lie between the insulator and the intermediate space and the intermediate space is connected to the recess or the recesses. The gap thus extends between the cavity of the recess and the side of the electrode blank, which lies opposite the cavity of the recess. The provision of the insulator or of the electrode blank with a recess has the advantage that the insulator, which lies above the separation point of the intermediate space, does not come into contact with the parting tool.

Preferably, two electrode blanks are applied to a carrier element, which are each divided into different filters. For example, Such an arrangement comprises two sections which are to become main filters and two sections which are to become prefilters, wherein a main filter section and a prefilter section are always connected to each other by an insulator.

The order of the above steps can be varied. For example, a recess is first introduced into the electrode blank, which divides the electrode blank into two sections. Subsequently, an insulator is positioned over the recess and connected to both sections. During the subsequent separation of the two sections by a gap, these sections are through the insulator in a constant relative position to each other held. Thereafter, a carrier element is connected to the insulator to be joined in a further step with another carrier element to an electrode device.

In a preferred embodiment, the gap is formed such that the presence of an insulator and / or a carrier element, which are positioned over the gap, through this gap have no influence on the field geometry of the multipole and thus do not affect the trajectory of ions.

The trajectory of the ions or the main direction of movement of the ions, neglecting their circular movement, is arranged along the electrode blank, namely in particular on the side of the blank electrode which lies opposite the side of the electrode blank fitted with the insulator means. The trajectory of the ions thus substantially corresponds to a longitudinal axis to the electrode blank, which after the o.g. Criteria, in particular on the opposite side of the insulator means, is arranged. In order to avoid influencing the field geometry, advantageously no normal to this longitudinal axis, a visual axis to the insulator means and / or the carrier element. A normal in this context is an axis which is at a 90 ° angle to the longitudinal axis.

Advantageously, the gap for example, on angled or is formed like a staircase or obliquely and / or the entry and exit point of the intermediate space from the blank are offset from each other. In particular, a training with angulations or a step-like design prevents the so-called "needle-point effect" disturbing the field geometry. Particularly preferably, the intermediate space angelnungen and the entry and exit point of the intermediate space from the blank are offset from each other.

Such an arrangement has the advantage that the probability that the ions pass through the gap to the insulator is greatly reduced. Thus, the ions can not establish direct contact with the surface of the insulator. Therefore, the ions can not react with the surface of the insulator, which is why no electrostatic charge of this surface can take place by the ions. With such a charge, the ion would namely absorb an electron of the insulator and would be neutralized with it. The insulator, on the other hand, would be positively charged, which would change the field geometry. An altered electric field would affect the trajectory of the other ions.

The intersection of the gap starts e.g. at the recess and is continued in the direction of the opposite side of the blank. The first section is thus formed transversely to the longitudinal axis of the blank, a second section along the longitudinal axis, whereupon a further section follows, which is aligned again transversely to the longitudinal axis. Of course, further angulations can be incorporated by further longitudinally and transversely to the longitudinal direction extending portions in the configuration of the intermediate space.

Further preferably, the transition from the recess to the intermediate space and the exit point of the intermediate space from the electrode blank are offset from one another, wherein in particular between a prefilter and a main filter, the exit point of the intermediate space from the electrode blank is preferably offset in the direction of flight of the ions. This prevents an undefined electric field from being generated by surface charging of the insulator, which would influence the trajectory of the further ions.

The offset between the entry and exit point of the gap in or out of the electrode blank may be mirrored at the transition between the main filter and post filter to the transition between prefilter and main filter, or in the same way, so not mirrored, be formed. A mirrored construction has the advantage that the main filter thereby symmetrical is trained. This results in a more homogeneous field, which means less interference for the ions. By contrast, a similar construction could also make use of the advantage in the transition between the main filter and the postfluter that the probability that the ions reach the insulator is kept even lower, since the exit point of the intermediate space from the electrode blank is offset in the direction of flight.

In a preferred embodiment, as a further step, the sections of the electrode blank are simultaneously processed together with the carrier element such that contours of the blank and of the carrier element are ground. Namely, the working is preferably carried out by grinding, in particular by the use of a grindstone. The individual sections of the electrode blank are preferably ground in the longitudinal direction so that a circular and a non-circular, in particular substantially hyperbolic, section is formed in the cross-section of the electrode blank. This has the advantage that a better field geometry is formed, resulting in a more accurate measurement. The joint processing of the electrode blank and carrier element by e.g. Grinding can take place temporally before separating the electrode blank into the two sections. Preferably, however, the processing is carried out after the separation cut. Alternatively, the processing of the electrode blanks may also be omitted, e.g. to save costs.

The end portions of the support members are formed convex and concave by the machining, so that they center themselves later in the pairwise assembly of the support elements. Such an approach has the advantage that a very precise alignment of the electrodes is ensured to each other and thus the electrodes no longer need to be adjusted after grinding. In particular, this procedure results in an accuracy of the electrode surfaces of <1 μm.

By editing each section, each section becomes an electrode. Each of these electrodes has a circular section and a substantially hyperbolic section as a result of the machining in cross-section. The respective similarly machined portions of all provided electrode blanks, in particular after being joined to the electrode device, form the individual filters, e.g. Prefilter and main filter.

In a preferred embodiment, the recess is introduced into the electrode blank by a machining or non-cutting (erosive) manufacturing process. Machining processes can e.g. Milling, sawing, planing, grinding or drilling. Non-cutting or abrading methods may e.g. be carried out by chemical or thermal removal. This includes the method of electroerosion, etching, laser cutting or water jet cutting. Preferably, the recess is introduced by a machining process in the electrode blank. In particular, the recess is sawn into the electrode blank. Alternatively, the recess can also be introduced by casting in the production of the blank.

In a preferred embodiment, the gap separating the sections of the electrode blank is made by a machining and / or non-cutting manufacturing process. In particular, in a machining process, the intermediate space is ground, milled or sawed into the electrode blank, for example with a wire saw. Alternatively, in non-chip manufacturing processes, the gap is made by electro-erosion, etching, laser cutting or water jet cutting. In particular, the production of the intermediate space takes place by means of wire erosion. The use of wire or electrical erosion has the advantage that substantially no mechanical stresses are generated in the components and a very accurate removal of the metal is possible. The fact that the recess is first introduced prevents the tool, eg the eroding wire, from coming into contact with the insulator when the intermediate space is produced. Of the Insulator holds both sections together during and after separation and acts as an insulator between the electrode and the support element.

A separation between pre- and post-filter and main filter is necessary in order to be able to act on the various sections differently with AC voltage and DC voltage. The pre- or post-filter is preferably applied only with an alternating voltage. Despite this separation between pre- and post-filter and main filter results from the present invention, an electrode or an electrode device to which no readjustment between the various sections is necessary because an insulator or the support member during the separation of the electrode blank holds both sections of the electrode blank together.

The invention thus shows an effective method for producing an electrode device with pre and / or post filters, wherein the electrodes are aligned with high precision, in particular with respect to the filter sections to each other and to the distances to the other electrodes of the multipole. The electrode device resulting from the method according to the invention has extremely straight electrode rods which have a very high parallelism to each other. Thus, now a multi-pole electrode device with pre and / or post filters is possible, which works with high accuracy and represents a strong improvement to the state of the art. In particular, the measuring method offers thanks to the invention by better focusing of the ion beam, a higher transmission rate of the ions and a higher resolution.

The product of the manufacturing method according to the invention, namely a very precisely working electrode device, has a plurality of electrode arrangements with at least one electrode blank, holding means and a gap separating the blank electrode into two sections, so that these axially spaced apart and thus are electrically isolated from each other. The holding means comprise insulator means and a support member, wherein at least parts of the insulator means hold the two sections in a constant relative position to each other. According to the invention, at least one insulator of the insulator means and / or the electrode blank has a recess. This recess in particular preferably has a greater extent in the longitudinal direction of the electrode blank than the intermediate space. At least one insulator of the insulator means is connected to the electrode blank and the carrier element. In particular, each pair of electrode blanks are connected to a support member and have been processed together so that the electrode portions each have a circular portion and a hyperbolic portion and the support members can adjust themselves when assembled, forming an electrode device.

The invention preferably comprises a multi-pole electrode device with at least two electrode arrangements according to the invention. Preferably, the electrode device is designed as a multipole, in particular as a quadrupole, and consists of two electrode arrangements according to the invention. The electrode arrangements preferably each comprise two sections, which are designed as main filters, and at least two sections, which are formed as prefilters, and / or at least two sections, which are designed as post filters. The individual sections are arranged according to the invention. The electrode assemblies are interconnected by the support members to form an electrode assembly. In particular, the carrier elements themselves center each other through the ground end sections, which are convex and concave and fit exactly into one another.

The invention further comprises a mass spectrometer with an electrode device according to the invention or a plurality of electrode arrangements according to the invention.

Fig. 1

eine schematische Ansicht einer Elektrode mit Pre- und Postfilter;

Fig. 2

eine schematische Darstellung der Verfahrensschritte S1 bis S5 zur Herstellung einer mit einem Prefilter-Abschnitt ausgestatteten Elektroden-Anordnung;

Fig. 3

eine alternative Ausführungsform von dem in Fig. 2 dargestellten Verfahrensschritt S4,

Fig. 4

eine schematische Querschnittsansicht des in Fig. 2 dargestellten Verfahrensschrittes S3,

Fig. 5

ein erläuterndes Schema zur Ausbildung des Zwischenraumes nach Schritt S4 der Fig. 2,

Fig. 6-9

mehrere alternative Ausführungsformen der Erfindung und

Fig. 10

eine schematische Zeichnung einer Seitenansicht einer Elektroden-Vorrichtung.

Further advantageous embodiments will become apparent from the dependent claims and from the attached drawings with reference to more detail embodiments. In the drawings show:

Fig. 1

a schematic view of an electrode with pre and post filter;

Fig. 2

a schematic representation of the process steps S1 to S5 for producing an equipped with a prefilter section electrode assembly;

Fig. 3

an alternative embodiment of the in Fig. 2 illustrated method step S4,

Fig. 4

a schematic cross-sectional view of the in Fig. 2 illustrated method step S3,

Fig. 5

an explanatory scheme for the formation of the gap after step S4 of Fig. 2 .

Fig. 6-9

several alternative embodiments of the invention and

Fig. 10

a schematic drawing of a side view of an electrode device.

Like reference numerals in the figures indicate like parts. The additional letters 9, 13, 15, 17, 19 and 25, such as 17a, denote the respective parts in the respective embodiment. Missing the indication of a letter, all embodiments of the respective part are meant. If, for example, the term "insulator 17" is found, all embodiments of the insulator, namely 17a to 17k, are meant.

Fig. 1 shows a schematically simplified electrode assembly 1 for use in a multi-pole electrode device, in particular in a multipole, a mass filter or mass spectrometer. The electrode assembly 1 is composed, inter alia, of a section for a main filter 3, a section for a prefilter 5 and a section for a postfilter 7. The invention is not limited to this embodiment. For example, an electrode arrangement 1 according to the invention may also have only one section for a prefilter 5 or only one section for a postfilter 7.

The portion for the prefilter 5 and the portion for the postfilter 7 are electrically separated from each other by the portion for the main filter 3 by gaps, to be differently supplied with AC voltage and DC voltage. The ions to be detected according to the set mass arrive at a multipole in operation, e.g. through the field of a pre-filter 5, where initially only AC voltage is applied, in the field of the main filter 3, where the DC voltage is added. The prefilter 5 ensures that the ions enter the field of the main filter 3 in a more stable state, whereby a better focusing of the ions is possible. The pre and post filters 5, 7 therefore work much like lenses.

In the field of the main filter 3, the ions are filtered according to their mass-to-charge ratios, whereby ions which do not correspond to the desired mass and are thus to be sorted out are attracted by the DC-charged electrodes and collide with the electrode electrode. Arrangement 1 are neutralized.

The ions which are to be counted and which are to hit the detector for this purpose are prevented from being defocused by an abruptly breaking off field at the end of the main filter 3 by the postfilter 7. Here, for example, DC voltage and AC voltage are gradually attenuated or the DC voltage completely switched off to achieve an even higher focus. Preferably, a post filter 7 is used in cases where further ion optical components are provided.

Fig. 2 shows a schematic representation of the process steps S1 to S5 for the preparation of an electrode assembly 1 with a prefilter 5. Postfilter 7 can be prepared in an analogous manner. In S1, first, an unprocessed electrode blank 9a is shown. This is preferably made of metal, in particular the metals Invar or Vacon come into question. In particular, the electrode blank 9 is manufactured as a round rod. Alternatively, however, the electrode blank 9 may also have a trapezoidal or rectangular cross-section, in which case it can then be used to guide the ions, for example around curves.

In step S2, a recess 11 is introduced into the electrode blank 9a, for example by sawing or milling. This recess 11 does not pass through the entire electrode blank 9a, but only affects the surface. The recess 11 divides the electrode blank into two sections 13a, 15a, which at the end of the manufacturing process represent the individual filters (for example main filter, prefilter).

In a step S3, an insulator 17a is applied to the electrode blank 9a, so that the insulator 17a partially or completely covers the recess 11 and the recess 11 is thus provided as a cavity in the electrode blank 9a below the insulator 17a. The insulator 17a is connected to both sections 13a, 15a. Preferably, the connection between the insulator 17 and the electrode rod assembly 9 is non-detachable and realized by adhesive. Preferably, the insulator 17 is formed as a quartz. Alternatively, the insulator 17 may also be made of ceramic. Preferably, the metal of the electrode blank 9 has a similar temperature expansion coefficient as the Insulator so that a permanent connection between the metal and insulator 17 is possible.

In a step S4, a gap 19 is made between the cavity and the opposite side of the electrode blank 9. Through this gap 19, the sections 13, 15 axially spaced from each other. There is thus an electrical separation between the sections 13, 15, so that the sections 13, 15 can be acted upon independently of one another with voltages. The insulator 17 holds the sections 13, 15 in a constant relative position to each other during the separation process, so that a complex adjustment is eliminated.

For the formation of the intermediate space 19, various methods are suitable. Particularly suitable for this are milling, drilling, sawing and electro-erosion. When sawing, it is preferred to use a wire saw or a saw wire, which may be e.g. can be occupied at short intervals with diamond segments. This method opens up the possibility of making the gap flexible and e.g. also to introduce corners. Particularly preferably, the production of the intermediate space 19 can be done by means of wire erosion cutting. The recess 11 prevents that e.g. the eroding wire comes in contact with the insulator 17 in the separation of the electrode blank 9, the two sections 13, 15.

A continuous section of the intermediate space 19 is necessary in order to be able to connect the two sections 13 and 15 of the electrode blank 9 separately from one another. In Fig. 2 For example, the first portion 13a may be regarded as a later part of the pre-filter 5 and the second portion 15a as a later part of the main filter 3. In the case that a production of a post-filter 7 takes place, the first section 13a corresponds to the main filter 3 and the second section 15a corresponds to the postfilter 7.

Preferably, the separation of the two sections 13, 15 through the recess 11 and the gap 19 is formed such that no normal to the longitudinal axis of the electrode blank 9, a visual axis to the insulator 17 forms. This has the advantage that the ions can not come into contact with the insulator 17 and thus no surface charging of the insulator 17 by the ions can take place. A surface charge of the insulator 17 would adversely affect the field geometry.

Preferably, the gap 19a for the latter training on angled or is formed like a staircase. The exit point 21 of the intermediate space 19a from the electrode blank 9a is preferably offset from the transition 23 between the recess 11 and the intermediate space 19a. Preferably, this offset is formed in the transition from prefilter to main filter in the direction of flight of the ions, i. the exit point 21 is closer to the main filter 3. This makes contact of the ions with the insulator 17a even more unlikely, since the ions, once moved in one direction, are unlikely to strike the opposite direction to pass through the gap 19a to the insulator 17a to arrive. Preferably, a sawing wire or a wire saw or the method of electroerosion are used for the cutting of angled or for the step-like training, as this very flexible cuts are possible.

In a step S5, at least one carrier element 25a is connected to the insulator 17a. The connection between the insulator 17 and the carrier element 25 is preferably carried out by gluing. On the carrier element 25, which is preferably formed semicircular in cross-section in cross-section, a further processed electrode blank 9 is preferably arranged. In a step S6 (not shown), the electrode blanks 9 are processed together with the carrier elements 25. The common processing is preferably done by grinding, in particular by a grindstone. The cross sections of the electrode blanks 9 thereby each receive a circular section and a non-circular, in particular substantially hyperbolic, section. The end portions of the support members 25 are simultaneously formed convex and concave to achieve later centering with another support member 25, a self-centering.

The advantage of such a method is a very precise arrangement of the electrode surfaces to each other, which could otherwise be achieved only with much more effort after grinding the items.

Fig. 3 shows an alternative embodiment of step S4, in particular from the gap 19a Fig. 2 , The gap 19b is formed such that it has an oblique section. Again, it is advantageous if - at least at the transition between pre-filter and main filter - the exit point 21 of the intermediate space 19b from the electrode blank 9b closer to the main filter 3 as the transition 23 between the recess 11 and the gap 19b.

Fig. 4 shows a cross-sectional view of step S3, wherein the viewer looks directly into the recess 11. The upper part of the electrode blank 9c is removed for the formation of the recess 11. The insulator 17c is applied over the recess 11, so that the recess 11 is at least partially covered by the insulator 17c. The gap 19c (not shown here) is then produced, for example, by wire erosion between the later exit point 21 and the cavity of the recess 11.

Fig. 5 shows a schematic view of the electrode blank 9d. The direction of flight 27 of the ions 29 is in the longitudinal direction, that is parallel to the longitudinal axis 31 of the electrode blank 9, fixed. The longitudinal axis 31 is arranged on the side of the electrode blank 9, which is opposite to the side on which the insulator 17 is applied. No normal 33 to the longitudinal axis 31 of the electrode blank 9 represents a visual axis to the insulator 17 is in particular this is ensured by the angulations and by the offset of the entry and exit points 21, 23 of the intermediate space 19d into and out of the electrode blank 9d. This measure completely or at least partially prevents the ions 29 from electrostatically charging the surface of the insulator 17d and thereby changing the field geometry.

Fig. 6 Figure 4 shows alternative embodiments A, B and C from step S4 Fig. 2 , Fig. 6A shows a recess 34, which is introduced into the insulator 17e instead of in the electrode blank 9e. Alternatively, as in Fig. 6B shown, the recess 11, 34 may be present both in the electrode blank 9f as well as in the insulator 17f. The recess 11, 34 respectively prevents the separating tool from coming into contact with the insulator 17f when the electrode blank 9f is separated into the two sections 13f, 15f. This is particularly important when the gap 19f is introduced by electroerosion in the electrode blank 9f. As another alternative, as in Fig. 6C shown, the insulator 17g and the electrode blank 9g without recess 11, 34 be configured.

Fig. 7 shows an alternative embodiment of the product according to the invention. Shown there are several short insulators 17h 'to 17h "", wherein in each case two of the insulators 17h' to 17h "" on a portion 13h, 15h are arranged. The use of a plurality of insulators 17h 'to 17h "", in particular by the arrangement in the outer regions of the sections 13h, 15h, increases the stability of the electrode assembly 1. The carrier element 25h is connected to the insulators 17h' to 17h ", wherein the two sections 13h, 15h are thereby held by the carrier element 25h in a constant relative position to each other. Preferably, the gap 19h is formed in this case staircase also in this case, so that there is no visual axis to the support member 25h here. The insulators 17h 'to 17h "" may also have different lengths.

Fig. 8 shows a further alternative embodiment, wherein in each case one long insulator 17i ', 17i "is arranged on each of the sections 13i, 15i, and such a design increases as the use of several short insulators 17h' through 17h""in FIG Fig. 7 , the stability of the electrode assembly 1.

Fig. 9 shows a further alternative embodiment, wherein a long insulator 17j interconnects both sections 13j, 15j. In this case, the support member 25 no longer holds the portions 13j, 15j together and in a constant relative position to each other but the insulator 17j placed over the gap 19j.

Fig. 10 shows an electrode device 35 which is composed of two electrode assemblies 1. The electrode assemblies 1 each have a carrier element 25, wherein the end portions 37 of the carrier elements 25 are convex and concave and with the other carrier element 25 fit into each other. The electrode blanks 9 are each attached to the inside of the support elements 25 by insulators 17 to the support elements 25. The electrode assemblies 1 are preferably machined prior to assembly to the electrode device 35, in particular ground, so that the electrode blanks 9 each have a circular portion and a substantially hyperbolic portion (not shown here) and the support member 25, the convex and concave shaped end portions 37 receives. The support members 25 may either be extended over almost the entire length of the electrode blanks 9, or may be arranged as ring-like elements at individual positions. When installed in a mass spectrometer, the electrode device 35 is fixed by means of the carrier elements 25 in the mass spectrometer.

All features mentioned in the preceding description and in the claims can be combined individually or in any combination with the features of the independent claims. The disclosure of the invention is therefore not limited to the described or claimed feature combinations. Rather, all in the context of the invention meaningful combinations of features are to be regarded as disclosed.

Claims (11)

1. A method of manufacturing a multipolar electrode device (35), in particular a multipole, for use in a mass spectrometer, wherein the electrode device comprises at least a main filter (3) and at least a pre- and / or post-filter (5, 7) and wherein the electrode device (35) comprises a plurality of electrode assemblies (1), wherein each electrode assembly (1) comprises one or more rod-shaped electrode blanks (9), and wherein the following steps are performed for manufacturing the electrode assembly (1):

   a) connecting (S3) each of the electrode blanks (9) with insulator means (17a, b, d-f), wherein said insulator means (17a, b, d-f) comprise at least one insulator (17a, b, d-f),

   b) separating (S4) each of the electrode blanks (9) into two sections (13, 15), wherein said sections (13, 15) are axially spaced apart from each other by a gap (19) and wherein said at least one insulator (17a, b, d-f) holds the sections (13a, b, d-f, 15a, b, d-f) in a constant relative position to each other during and after separation (S4),

   c) performing said separation step (S4) as often as the intended number of pre- and / or post-filters (5, 7),

   d) connecting (S5) a support member (25) with said at least one insulator (17) and

   e) joining said plurality of electrode assemblies (1) together by connecting the support members (25) in order to build said electrode device (35),
   characterized in that

   f) said electrode blank (9a-d, f) and / or said insulator (17e, f) are provided with a respective recess (11, 34) (S2), wherein said recess or recesses (11, 34) being arranged such that the recess or recesses (11, 34) is / are between said insulator (17a, b, d-f) and said gap (19a, b, d-f) and wherein said gap (19a, b, d-f) being connected with said recess or recesses (11, 34).
2. The method according to claim 1,
   characterized in that
   said gap (19) is formed such that, starting from a longitudinal axis (31) of the electrode blank (9), said axis being arranged on that side of the electrode blank (9) which is opposite to the side with the insulator (17) is, no normal (33) to this longitudinal axis (31) constitutes a line of sight to said insulator (17) and / or to said support member (25).
3. A method according to claim 1 or 2,
   characterized in that
   the electrode blank (9) is processed together with the support member (25) such that the cross section of the electrode blank (9) receives a circular portion and a non-circular portion, in particular an essentially hyperbolic portion, and the support member (25) receives two differently shaped end portions (37), said end portions (37) having shapes that are adapted to each other.
4. A method according to one of the preceding claims,
   characterized in that
   the gap (19) is produced by sawing, milling, grinding, laser cutting, water jet cutting, etching or electric discharge.
5. A method according to one of the preceding claims,
   characterized in that
   the recess (11, 34) in the electrode blank (9a, d, f) and / or the at least one insulator (17e, f) is provided by sawing, milling, grinding, laser cutting, water jet cutting, etching or electro-erosion and the recess (11) in the electrode blank (9a, d, f) is alternatively provided by casting.
6. A multipolar electrode device, in particular multipole, for use in a mass spectrometer, wherein the electrode device (35) comprises at least a main filter (3) and at least a pre- and / or post-filter (5, 7) and wherein the electrode device (35) comprises a plurality of electrode assemblies (1), wherein each electrode assembly (1) comprises one or more rod-shaped electrode blanks (9) and

   a) each electrode blank (9) is connected with insulator means (17a, b, d-f), wherein said insulator means (17a, b, d-f) comprise at least one insulator (17a, b, d-f),

   b) for each pre- and / or post-filter (5, 7) a gap (19) separates the electrode blanks (9) respectively into two sections (13, 15), wherein the sections (13, 15) are axially spaced apart from each other by means of the gap (19) and wherein said at least one insulator (17a, b, d-f) holds the sections (13a, b, d-f, 15a, b, d-f) in a constant relative position to each other,

   c) a support member (25) is connected with said at least one insulator (17), and

   d) the plurality of electrode assemblies (1) are joined together by connecting the support members (25) in order to build said electrode device (35),
   characterized in that

   e) said electrode blank (9a-d, f) and / or said insulator (17e, f) comprise a respective recess (11, 34), which is / are connected with said gap (19a, b, d-f) and separates / separate said insulator (17a, b, d-f) from said gap (19a, b, d-f).
7. The electrode device according to claim 6,
   characterized in that
   said gap (19) is formed such that, starting from a longitudinal axis (31) of the electrode blank (9), said axis being arranged on that side of the electrode blank (9) which is opposite to the side with the insulator (17) is, no normal (33) to this longitudinal axis (31) constitutes a line of sight to said insulator (17) and / or to said support member (25).
8. The electrode device according to claim 6 or 7,
   characterized in that
   the electrode blank (9) is processed together with the support member (25) such that the cross section of the electrode blank (9) having a circular portion and a non-circular portion, in particular an essentially hyperbolic portion, and the support member (25) having two differently shaped end portions (37), said end portions (37) having shapes that are adapted to each other.
9. The electrode device according to any one of claims 6 to 8,
   characterized in that
   the gap (19) is produced by sawing, milling, grinding, laser cutting, water jet cutting, etching or electric discharge.
10. The electrode device according to any one of claims 6 to 9,
    characterized in that
    the recess (11, 34) in the electrode blank (9a, d, f) and / or the insulator (17e, f) is provided by sawing, milling, grinding, laser cutting, water jet cutting, etching or electro-erosion and the recess (11) in the electrode blank (9a, d, f) is alternatively provided by casting the electrode blank (9a, d, f).
11. A mass spectrometer with a multipolar electrode device (35) according to any one of claims 6 to 10,
    characterized in that
    the multipolar electrode device (35) comprises at least two electrode assemblies (1).

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