EP3385979B1 - Device with a multipole and a holding device arranged on the multipole, mass spectrometer with such a device, mounting unit for positioning the holding device relative to the multipole and method for positioning the holding device relative to the multipole - Google Patents

Description

The invention relates to a device comprising a multipole having two electrode half-shells and electrodes arranged thereon, and a holding device arranged on the multipole for holding the multipole, for example a quadrupole in a mass spectrometer. The invention further relates to a mass spectrometer with such a device, a mounting unit with a receiving device configured and adapted for positioning the holding device relative to the multipole of the device, and a method for positioning the holding device relative to the multipole of such a device by means of the mounting unit.

In the field of mass spectrometry, multipolar electrode devices, also called multipoles, have been known from the prior art for several decades, e.g. from the German patent specification. DE 944900 The electrode device shown there serves as an analyzer in a mass spectrometer for the separation or separate detection of ions according to their mass-to-charge ratio. A mass spectrometer essentially comprises three components: an ion source, an analyzer which serves as a mass filter, and a detector. In the case of such multipole mass filters, as known, for example, from the patent specification mentioned above, the separation process functions without a magnetic field.

In a quadrupole mass spectrometer, such a multipole or analyzer is configured as a quadrupole. This quadrupole comprises four rod electrodes, for example, four metal rods, arranged parallel to one another, with the intersections of their longitudinal axes and a perpendicular plane forming a square. Diagonally opposite electrodes are held at the same potential, which consists of a direct current (DC) and an alternating current (AC) component. Each pair of diagonally opposite electrodes is thus subjected to a DC and a high-frequency voltage, with the two high-frequency voltages phase-shifted by 180°. The ions to be separated are directed as a fine ion beam along the length of the electrodes into the field of the quadrupole.

The applied alternating and direct current causes the ions to move along defined trajectories through the quadrupole. Outside of stable boundary conditions, the ions collide with the electrodes, neutralizing them and preventing them from reaching the detector. The edges of the electrodes can represent unstable zones for the ions, thus contributing to defocusing. This phenomenon is already known in the prior art.

Out of DE 10 2013 111 254 A1 For example, an electrode device is known which allows for precise alignment The invention ensures the precise alignment of the electrodes with each other, thus resulting in high analytical measurement accuracy. Furthermore, the invention provides an electrode assembly with pre- and/or post-filters, which are arranged before and after a main mass filter, respectively. These pre- and post-filters serve to introduce and expel the ion beam, thereby focusing it and thus increasing the ion transmission rate and consequently achieving higher resolution of the mass spectrometer. The various sections of the electrodes functioning as mass filters act as ion-optical lenses, and the entire electrode assembly therefore constitutes an ion-optical element, particularly in a mass spectrometer.

Precise alignment of the electrodes relative to each other is essential for analytical measurement accuracy and is achieved by attaching the electrodes to at least one support element. The support elements are assembled with high positional accuracy to form an electrode assembly, thus ensuring high analytical measurement accuracy in a mass spectrometer. When installed in a mass spectrometer, the electrode assembly is secured within the instrument by means of the support elements. For this purpose, the support elements are, for example, arranged in a ring shape around the electrodes at the front and rear, or a ring of insulating material is arranged around the support elements at each end face of the multipole. The electrode assembly thus has rotationally symmetrical contact surfaces with which it rests within the mass spectrometer, particularly against a corresponding mounting device inside the instrument. However, such rotationally symmetrical contact surfaces do not allow for highly precise positioning and alignment of the electrode assembly or the multipole, for example, within a mass spectrometer.

Other electrode devices are made of EP 1 657 737 A2 , US 2004/245460 A1 , DE 10 2012 211 586 A1 and DE 10 2021 211 587 A1 known. EP 1 657 737 A2 and US 2004/245460 A1 This demonstrates how electrodes are ground together with electrode half-shells. These ground surfaces of the electrode half-shells completely cover each other, so that it is not possible to attach other parts to the ground surfaces. DE 10 2012 211 586 A1 shows a multipole degradation group and a method for its production, wherein according to Fig. 6A An insulator ring is provided, on which electrodes are arranged. According to Fig. 7 Holders for electrodes are provided, and the underlying components have a U-shaped shape to act as holding devices. DE 10 2012 211 587 A1 The figure generally shows a mass spectrometer with precisely aligned ion optic assemblies, but without the use of electrode half-shells.

The invention is based on the objective of providing a multipole with a holding device that enables precise positioning of the multipole and simplified installation and removal of the multipole, e.g., in a mass spectrometer. Furthermore, the invention aims to contribute to increasing the measurement accuracy of mass spectrometers.

The invention solves this problem with a device comprising a multipole having two electrode half-shells and electrodes arranged thereon, and a holding device arranged on the multipole for holding the multipole, with the features according to claim 1. Furthermore, the invention solves this A mass spectrometer having the features of claim 10, comprising such a device, a mounting unit having the features of claim 11 and a method for positioning the holding device relative to the multipole having the features of claim 12.

The invention is based on the understanding that, conventionally, an electrode device or a multipole, e.g., in a mass spectrometer, is preferably mounted using a ring-shaped holding device arranged on the support elements of the electrode device. This holding device is designed in two parts, with each ring arranged on the end faces of the multipole and enclosing the support elements. Such a holding device has two circumferential, rotationally symmetrical contact surfaces which, when the multipole is mounted on a corresponding receiving device, particularly in a mass spectrometer, at least partially bear against it. However, such rotationally symmetrical contact surfaces do not allow for highly precise positioning and alignment of the electrode device or the multipole, e.g., within a mass spectrometer.

According to the invention, a device is therefore provided which comprises a multipole, for example a quadrupole, having two electrode half-shells and electrodes arranged thereon, and a holding device arranged on the multipole for holding the multipole, for example for holding the multipole in a mass spectrometer or on a mounting unit, thereby making it particularly easy to achieve high-precision alignment and positioning of the multipole.

The holding device is constructed in one or more parts and is arranged on the multipole to attach the multipole to a receiving device for the holding device. For this purpose, the holding device has one or more flat contact surfaces that correspond to the receiving device. The holding device is positioned on surfaces of the electrode half-shells of the multipole, which are manufactured together with the electrode surfaces of the multipole's electrodes in a single operation by grinding them together with the same grinding wheel. This ensures that these surfaces have a unique and precise geometric relationship to the electrode surfaces ground in this way. That is, these surfaces and the electrodes are ground together with the same grinding wheel. The surfaces for arranging and thus attaching the holding device to the multipole therefore have a unique and precise geometric relationship to the precisely machined electrode surfaces. This ensures that the electrode surfaces, and in particular their centers, can be aligned exactly with the holding device. This also allows the multipole to be precisely aligned within the mass spectrometer.

Furthermore, the holding device is preferably arranged on the multipole in such a way that the one or more flat support surfaces are arranged rotationally asymmetrically with respect to the central longitudinal axis of the multipole.

Preferably, each flat support surface lies in a plane that is parallel to the central longitudinal axis of the multipole. The multipole is manufactured with high precision and has a precisely defined mounting position on the mounting device. This advantageously allows for a precise definition of the multipole's mounting position and a determination of its angular position relative to its central longitudinal axis. This enables highly precise alignment of the multipole's central longitudinal axis with a target axis of a mounting unit or mass spectrometer, such as a connecting axis between a source (e.g., an ion or electron source) and a detector, or with an axis of several ion-optical or electron-optical components arranged in series (e.g., ion-optical or electron-optical lenses or filters). This allows for highly precise positioning of the multipole at a target position within the mass spectrometer or mounting unit.

Furthermore, the invention simplifies the installation and removal of the multipole, for example, in a mass spectrometer, since the flat contact surfaces of the holding device result in only two mounting positions for the multipole on the receiving device, at least with regard to its angular position relative to its central longitudinal axis. This leads to reduced time and therefore lower costs during maintenance or repair. Moreover, this simplification reduces the risk of damage, mispositioning, or misalignment of the multipole during maintenance or repair work. The holding device, due to its design features and configuration described below, can also serve as a holder or handle for the multipole.

The rotationally asymmetric design of the support surfaces of the holding device according to the invention, in contrast to the rotationally symmetric design of the support surfaces according to the prior art, determines the angular position of the multipole with respect to the central longitudinal axis of the multipole in the fixed state, which advantageously simplifies the calibration of the measuring system after installation and removal of the multipole in a mass spectrometer and generates reproducible measured values of the mass spectrometer.

According to a further development of the invention, the holding device is arranged laterally to a cylindrical surface enclosing the multipole. This has the advantage that the flat contact surfaces can be machined in the longitudinal direction of the multipole, and in particular ground to a high degree of precision.

Advantageously, this machining of the flat contact surfaces of the holding device is carried out in a single grinding operation together with the electrodes and mounting surfaces of the support elements of the multipole. This advantageously ensures a highly precise alignment of the flat contact surfaces of the holding device with respect to the electrode surfaces.

In a further development of the invention, the holding device is arranged in a central section of the enclosing cylindrical surface, wherein this central section is arranged symmetrically to the central transverse axis of the multipole and corresponds to a maximum of 90% of the cylindrical surface. Advantageously, the holding device is designed in two parts, with each part of the holding device being arranged on one side of a cross-sectional plane through the central longitudinal axis of the multipole, in particular centrally or symmetrically to the central transverse axis of the multipole. Such an arrangement of the holding device ensures Advantageously, this ensures particularly high stability of the multipole's mounting, especially in the presence of vibrations or shocks, e.g., in a mass spectrometer or on a mounting unit.

The arrangement of the holding device within the central section essentially describes the arrangement with a recess for the end faces of the multipole. The lateral arrangement of the holding device outside the end faces of the multipole advantageously allows for axial insertion of the multipole into a mass spectrometer, i.e., insertion parallel to the system axis of the mass spectrometer, which makes it particularly easy to insert and/or remove the multipole from a mass spectrometer from above.

According to a further development of the invention, the holding device comprises one or more positioning means with which the holding device can be aligned on a receiving device. These positioning means are manufactured with high precision, in particular with a form and/or positional tolerance of IT5 to IT11 according to the ISO basic tolerances. This advantageously allows for an exact geometric position in all axial directions of the multipole, as well as relative to other components of the mass spectrometer, to be achieved in the installed state of the multipole, e.g., in a mass spectrometer, by means of the contact surfaces and the positioning means. The positioning means are particularly preferably manufactured with ISO basic tolerances IT6 to IT8.

The International Organization for Standardization (ISO) defines basic tolerances with the abbreviation IT for nominal dimensions from 1 to 500 mm as follows: Basic tolerances IT Nominal size ranges in mm 1 >3 >6 >10 >18 >30 >50 >80 >120 >180 >250 >315 >400 -2 -6 -10 -18 -30 -50 -80 -120 -180 -250 -315 -400 -500 Tolerances in µm 5 4 5 6 8 9 11 13 15 18 20 23 25 27 6 6 8 9 11 13 16 19 22 25 29 32 36 40 7 10 12 15 18 21 25 30 35 40 46 52 57 63 8 14 18 22 27 33 39 46 54 63 72 81 89 97 9 25 30 36 43 52 62 74 87 100 115 130 140 155 10 40 48 58 70 84 100 120 140 160 185 210 230 250 11 60 75 90 110 130 160 190 220 250 290 320 360 400

Advantageously, the flat contact surfaces of the holding device are also manufactured with high precision, so that together with a highly precise manufactured receiving device as a perfectly fitting counterpart, a highly precise alignment of the multipole in its geometric position is made possible.

Advantageously, two flat bearing surfaces are arranged on opposite sides of the holding device. These surfaces are manufactured with high precision and are parallel to each other, with a form and/or position tolerance of IT5 to IT11 according to the ISO basic tolerances. Furthermore, the thickness of the holding device, or the height between the parallel bearing surfaces, is manufactured with high precision, particularly with a form and/or position tolerance of IT5 to IT11 according to the ISO basic tolerances.

In the fixed state of the multipole, at least one flat contact surface rests against the receiving device, while the opposite, plane-parallel contact surface of the holding device does not rest against the receiving device. The two plane-parallel opposing contact surfaces advantageously allow for a multi-part holding device made of identically manufactured parts, where, prior to assembly, it is not known which of the flat contact surfaces rests against a receiving device.

The high-precision positioning devices also enable precise alignment of the multipole in the longitudinal direction of the multipole relative to a connecting axis between the source, e.g., ion source or electron source, and the detector, or to an axis of several ion-optical or electron-optical components arranged one behind the other, which is of great importance for high analytical measurement accuracy of the mass spectrometer.

The invention recognizes that achieving increasingly higher measurement accuracies requires more than simply increasing the precision of a multipole. Furthermore, the ever-increasing precision of the multipole can lead to measurement inaccuracies resulting from its less precise mounting within the mass spectrometer. The precise mounting of the multipole within the mass spectrometer according to the invention thus advantageously generates a further increase in the measurement accuracy and sensitivity of the measuring system. Increasing the precision of the multipole therefore also leads to an increase in the measurement accuracy and sensitivity of the measuring system, because the limitations imposed by insufficiently precise positioning and alignment of the multipole no longer exist.

Any positioning means that enables highly precise positioning and alignment of the multipole on a receiving device is possible, such as a hole or bore which, with a suitable fastening element such as a dowel pin or dowel screw, enables highly precise positioning and alignment of the multipole, e.g. in relation to the optical axis of the mass spectrometer, which corresponds to the ideal beam path of the ions.

Furthermore, in the high-precision manufacturing of the holding device according to the invention, the shaping of the holding device as a positioning means is possible if it has mating surfaces which interact with a corresponding shaping or mating surfaces on the receiving device.

A further development of the invention provides that the holding device is connected to the receiving device by at least one positioning means, such as a hole and/or a bore, in the holding device. is able to be positively connected or connected in the radial direction of the fastening element by means of a fastening element designed to fit the hole and/or bore, in particular by means of a dowel pin or dowel pin screw.

The arrangement of the hole and bore(s) of the holding device corresponds to the (geometric) arrangement of receiving bores in the receiving device, which serve to fit dowel pins or dowel pin screws, such that when the holding device is mounted on the receiving device, the holes and/or bores find a congruent counterpart in the receiving bores. The center axes of the holes and/or bores in the holding device are aligned with the center axes of the receiving bores in the receiving device.

The dowel pins or dowel screws connecting the holding device and the receiving device are designed to fit the inner diameters of the bores and/or holes and the outer diameters of the pins, in particular with form and/or position tolerances according to ISO basic tolerances IT5 to IT11. This fitting is preferably a contact, for example an interference fit or a plug connection. This advantageously enables quick and precise alignment of the multipole in a mass spectrometer using the holding device.

The connection running through the bores and receiving bores is positively locked in the radial direction of the dowel pins or with the precisely ground collar of the dowel pin screws, so that the dowel pins and the bores thus serve as a locating bore. This ensures advantageously precise positioning of the holding device on the receiving device, whereby the accuracy depends on the selected manufacturing tolerances, but with a form and/or positional tolerance of at least ISO basic tolerances IT5 to IT11, preferably with ISO basic tolerances IT6 to IT8.

The arrangement of the holding device and receiving device advantageously forms a system for highly precise alignment or positioning of the multipole in a mass spectrometer or on a mounting unit.

According to a further development of the invention, the multipole is attached to a holding device with at least one hole, which is designed as an elongated hole, wherein the width of the elongated hole is equal to the diameter of the corresponding receiving bore in the receiving device. Likewise, the diameter of the at least one bore in the holding device is equal to the width of the elongated hole. The diameters of the bores and the receiving bores are thus of the same size. The holding device can therefore advantageously be connected to the receiving device through the at least one bore and the at least one elongated hole by means of pins of the same diameter into the receiving bores of the receiving device. Designing the hole in the holding device as an elongated hole advantageously prevents tilting when connecting the holding device to the receiving device by means of the pins. Tilting is also avoided when the pins are already inserted in the receiving device and the holding device is... which is placed on these pins.

In a further development of the invention, the holding device for the multipole is designed as a two-part device, each part of which is arranged on one electrode half-shell or a support element of the multipole, which is preferably designed as a quadrupole. Both parts of the holding device, as well as the electrode half-shells of the quadrupole, are identical. However, the invention is not limited to a two-part device as a holding device. Rather, the holding device according to the invention can also be designed as a single piece and, in that case, is preferably arranged vertically below the multipole when installed, in order to minimize the transmission of vibrations to the multipole.

In a two-part embodiment of the holding device, both parts of the invention each have a hole, preferably an elongated hole, and a locating bore. According to this embodiment, the holding device thus has two bores and two holes, and the receiving device preferably has four locating bores, which are arranged such that the geometric arrangement of the locating bores in the receiving device corresponds to the arrangement of the holes and bores in the holding device. The diameters of the bores and the locating bores are the same, and the hole in the holding device is preferably designed as an elongated hole and has a width that is the same as the diameter of the locating bores in the receiving device. The holding device can thus advantageously be connected to the receiving device through the two bores and the two elongated holes by means of identically designed pins in or through the locating bores. These identically designed pins are preferably locating pins and each has the same length and diameter.

The identical parts used for the holding device of a multipole according to the invention, as well as the use of identical pins, leads to advantageously low production costs due to higher quantities of identical (component) parts. Likewise, the identical design of parts of a device results in low component diversity, which advantageously simplifies the maintenance or repair of such a device. This, in turn, leads to a reduction in costs and effort in the event of maintenance or repair.

In an alternative embodiment of the invention, a connection between the holding device and the receiving device can be established by means of a dowel pin screw. For this purpose, the dowel pin screw has a high-precision ground collar, which advantageously has a form and/or positional tolerance according to ISO basic tolerances IT5 to IT11 and fits through a corresponding hole in the holding device. By directly fastening the holding device to the receiving device using dowel pin screws, the additional holes and associated dowel pins required for high-precision alignment can be omitted.

In a further alternative embodiment of the invention, a connection between the holding device and the receiving device by means of a keyway. This requires only one slot, groove, or milled recess in both the holding device and the receiving device. Thus, the holding device can advantageously be aligned and positioned on the receiving device by means of a single connection, this connection being established by means of a keyway through a slot and in a groove. In this case, the slot is designed such that it has a contour matching the shape of the keyway. This slot is provided either in the holding device or the receiving device. The other device or device has a groove or milled recess with a contour matching the shape of the keyway.

According to a further embodiment of the invention, the multipole is attached to a holding device which can be connected to the multipole via roof edge and prism connections, wherein the multipole can be divided along its central longitudinal axis into at least two sections or two support elements, of which the two electrode half-shells are the components, which can also be joined together via roof edge and prism connections. Each roof edge and prism connection has a roof edge structure and a prism structure on the electrode half-shells or a roof edge element on the holding device and a prism structure on the electrode half-shell, which are configured to correspond to each other in that the roof edge structure or roof edge element is roof-shaped and the prism structure is channel-shaped. The roof edge structures or roof edge elements and the prism structures are aligned with each other with respect to a parallel running to the central longitudinal axis of the multipole, and each roof edge structure or roof edge element can be interlocked with a prism structure. The connecting elements or surfaces of the multipole segments (roof edge structure and prism element) and the receiving surfaces of the holding device (roof edge element) are identically channel- or roof-shaped, allowing them to be joined together and manufactured using the same tool. The receiving surfaces or elements of the holding device are therefore identical to the roof edge structures of the electrode half-shells, forming roof edge elements and corresponding to the prism structures of the electrode half-shells.

The aligned, channel- or roof-shaped design of the prism structures or roof edge structures (connecting elements) and the roof edge elements (receiving elements), as well as their corresponding shape, advantageously ensures guidance along the axis of alignment. Crucial for this function is the alignment of the two shapes, roof edge and prism, which prevents and thus eliminates movement perpendicular to the corresponding axis of alignment, which in this case is parallel to the central longitudinal axis of the multipole. The identical design of the roof edge structures of the electrode half-shell of the multipole and the roof edge elements of the holding device ensures an advantageously uniform relative alignment of the multipole to the holding device with respect to this central longitudinal axis.

To achieve precise guidance over the guide surfaces within the manufacturing tolerances for form and/or position, particularly according to ISO basic tolerances IT5 to IT11, but especially preferably IT6 to IT8, high-precision machining of the roof edge structures and prism structures designed as guide surfaces, as well as the roof edge element, is necessary. For advantageously parallel The roof edge elements of the holding device are machined simultaneously, in the same machining step, and with the same tool as the electrode half-shells. This advantageously minimizes or prevents the natural accumulation of manufacturing errors, which are unavoidable due to the inherent tolerances of each machining and/or manufacturing process. Thus, the accuracy of the guide remains within the manufacturing tolerance of the tool used to produce the surfaces. Therefore, a high degree of product precision can be achieved when using a precision tool. Simultaneous manufacturing results in advantageously fast and thus cost-effective production. Furthermore, simultaneous manufacturing and the identical design of the connecting and receiving surfaces advantageously mean that only one tool is required, thereby also reducing production costs and effort.

To achieve high precision and accuracy on these surfaces, grinding is advantageous. Grinding has the benefit of producing very low surface roughness, resulting in minimal friction between the joined surfaces. Furthermore, grinding allows for highly precise machining, thus achieving the desired high accuracy.

According to a further embodiment of the invention, the coefficient of thermal expansion of the holding device is equal to the coefficient of thermal expansion of the support elements or electrode half-shells of the multipole. The holding device and the electrode half-shells of the multipole are preferably made of metal which, within a material-specific tolerance, has a coefficient of thermal expansion that is as similar as possible. The material of the holding device is advantageously similar to the material of the electrode half-shells. The similarity of the two materials is manifested in the fact that the coefficient of thermal expansion of the holding device differs from the coefficient of thermal expansion of the electrode half-shells by a maximum of 5%, in particular 2.5%, preferably 1%, and most preferably 0.1%.

Advantageously, both materials have a low coefficient of thermal expansion, thus minimizing thermally induced expansion of the material and therefore changes in the workpiece's length. The similarity, and in particular the identicalness, of the material and its thermal properties offers the advantage that any stresses that might occur at the connecting surfaces of the two devices, which could, for example, cause relative displacements, are minimized, and in particular prevented.

However, the invention is not limited to the use of identical coefficients of thermal expansion. Rather, different coefficients of thermal expansion are also possible for the support elements and the holding device of the multipole if, for example, for cost reasons, the holding device is made of a more economical material, e.g., V2A steel.

According to a further development of the invention, the multipole is attached to a holding device with through holes and/or threaded holes, wherein the through holes and/or threaded holes of the holding device The holding device is arranged correspondingly to through holes and/or threaded bores of a receiving device. This allows for advantageous locking of the holding device to the receiving device by means of a screw connection using appropriate screws, in particular thin-shank screws or dowel pin screws. This locking serves to fix the holding device perpendicular to the radial direction of the through holes and/or threaded bores. In the present case, this is a fixation along an axis that is perpendicular to a plane that completely contains the central longitudinal axis of the multipole. Thus, the number of degrees of freedom or free directions of movement is reduced. In particular, the holding device preferably has two, in particular three, in particular four, through holes or threaded bores, and the receiving device has through holes or threaded bores arranged correspondingly to these through holes or threaded bores, in particular congruent ones.

Preferably, each threaded hole corresponds to a through hole to fix the holding device to a receiving device by means of a screw. If both the holding device and the receiving device have threaded holes or partially threaded holes, fixing is preferably achieved using suitable thin-shank screws in which part of the thread or unthreaded section is turned down and which only have a corresponding mating thread in the area of the corresponding threaded hole. Such thin-shank screws are advantageously designed to be captive.

In an alternative embodiment of the invention, the holding device can also be secured to the receiving device by means of a clamping fastener. Such a locking system preferably comprises a clamping hook and a counter-hook, which can be designed as a bracket, clamp, or lever.

In the multipole according to the invention, at least two, three or more of the above-described developments can be combined with each other in order to obtain meaningful combinations of features within the scope of the invention.

Preferably, the holding device can be arranged on a mounting device of a mass spectrometer, a mounting unit, and/or a unit used for the maintenance or repair of the multipole. Preferably, the holding device has at least one roof edge structure and at least one prism structure for attaching the holding device to the multipole. The holding device according to the invention thus serves for the high-precision alignment, positioning, and holding of the multipole, for example, a quadrupole, e.g., in a mass spectrometer or on a mounting unit.

Furthermore, the aforementioned problem is solved by means of a mass spectrometer with such a device according to the invention and with a receiving device for receiving the holding device of the multipole, wherein the holding device of the multipole enables the multipole to be held in an exact geometric position with respect to all axes of the multipole and relative to other components of the mass spectrometer. This is achieved through the high-precision alignment and positioning of the high-precision manufactured components. By comparing the mass spectrometers to each other, the overall resolution, sensitivity and performance of the mass spectrometer can thus be advantageously increased, in order to advantageously contribute to increasing the measurement accuracy of mass spectrometers.

Furthermore, the above-mentioned task is solved by means of an assembly unit with a receiving device that is set up and adapted for positioning the holding device relative to the multipole, in particular quadrupole.

The mounting unit according to the invention, with a receiving device for positioning a holding device relative to the multipole, provides that the mounting unit has a base plate. In use, this base plate is oriented perpendicular to the central longitudinal axis of the multipole arranged on the receiving device of the mounting unit and parallel to the direction of gravity. Such a design of the mounting unit enables advantageously precise positioning of the holding device relative to the multipole, as well as of the support elements or electrode half-shells of the multipole relative to each other. Thus, precise alignment and holding of the multipole according to the invention by means of the holding device in a mass spectrometer is advantageously enabled.

Advantageously, an exact positioning of the electrodes relative to each other, especially the starting and ending points of their sections, can also be ensured, thereby reducing disturbances of the electric field in the multipole.

According to the invention, the mounting unit comprises a rear wall which has recesses, in particular perforated recesses. These perforated recesses provide a visual connection from the outside through the rear wall of the mounting unit to the connecting elements of the holding device and the multipole and/or the electrode half-shells of the multipole, which are preferably designed as screw connections. This visual connection ensures that the screw connections, in particular the screws, are accessible through these recesses, for example with a screwdriver.

Due to the use of the mounting unit for positioning the holding device relative to the multipole and the electrode half-shells of the multipole relative to each other, the mounting unit can also be referred to as a positioning unit.

The use of a mounting unit has the advantage that the holding device and the electrode half-shells of the multipole can be mounted within this unit and thus aligned relative to each other. This allows for a kind of calibration of the holding device's position relative to the multipole, and therefore pre-alignment before the holding device and multipole are installed in the mass spectrometer. For this purpose, the mounting unit comprises a receiving device according to the invention, a base plate that ensures precise alignment of the electrodes relative to each other, and corresponding recesses that allow access to screws. These screws serve to lock the precise positioning of the holding device relative to the multipole. and, if applicable, the electrode half-shells of the multipole relative to each other.

This advantageously allows for the alignment and precise positioning of the holding device relative to the multipole before insertion or installation into the mass spectrometer.

Further developments of the invention are described in the claims, the description, and the drawings. The aforementioned advantages of features and combinations of features are exemplary and can be achieved alternatively or cumulatively, without necessarily requiring that the advantages be obtained in specific embodiments of the invention. Further features can be seen in the drawings—in particular, the geometries and relative dimensions of several components to one another, as well as their relative arrangement and functional connection. The combination of features from different embodiments of the invention or features from different claims is also possible, deviating from the chosen cross-references in the claims, and is hereby proposed. This also applies to features that are illustrated in separate drawings or mentioned in their description. These features can also be combined with features from different claims. Likewise, features listed in claims can be omitted for further embodiments of the invention.

Fig. 1a-d

eine Haltevorrichtung eines erfindungsgemäßen Multipols aus verschiedenen Perspektiven,

Fig. 2a-c

eine Elektrodenhalbschale eines Quadrupols zusammen mit einer Haltevorrichtung aus verschiedenen Perspektiven,

Fig. 3a

ein zwei Elektrodenhalbschalen umfassender Multipol zusammen mit einer Haltevorrichtung in perspektivischer Ansicht,

Fig. 3b

ein zwei Elektrodenhalbschalen umfassender Multipol zusammen mit einer Haltevorrichtung in seitlicher Ansicht entlang der Mittellängsachse des Multipols,

Fig. 4

eine seitliche Ansicht eines zwei Elektrodenhalbschalen umfassenden Multipols zusammen mit einer Haltevorrichtung an bzw. auf einer Aufnahmeeinrichtung,

Fig. 5

eine frontale Ansicht einer leeren Montageeinheit ohne Multipol und Haltevorrichtung,

Fig. 6a,b

eine seitliche und eine frontale Ansicht der Montageeinheit mit Multipol und Haltevorrichtung,

Fig. 7a-d

mehrere Ausführungsbeispiele für eine Haltevorrichtung,

Fig. 8a-d

mehrere Ausführungsbeispiele für in die Haltevorrichtung eingebrachten Löcher und Bohrungen,

Fig. 9

der Multipol gemäß Fig. 4 ohne Aufnahmeeinrichtung mit übertrieben dargestellt ungenau gearbeiteten äußeren Konturen der Elektrodenhalbschalen und

Fig. 10

der Multipol gemäß Fig. 9 ohne die in Fig.9 dargestellte erfindungsgemäße Haltevorrichtung, jedoch mit einer herkömmlichen ringförmig ausgebildeten Haltevorrichtung zur Veranschaulichung eines unerwünschten Versatzes des gemeinsamen Mittelpunkts der Elektroden des Multipols gegenüber dem Mittelpunkt der äußeren Kontur der Elektrodenhalbschalen.

Further embodiments of the invention are described in the claims and in the exemplary embodiments explained in more detail with reference to the drawing. The drawing shows:

Fig. 1a-d

a holding device of a multipole according to the invention from different perspectives,

Fig. 2a-c

an electrode half-shell of a quadrupole together with a holding device from different perspectives,

Fig. 3a

a multipole comprising two electrode half-shells together with a holding device in perspective view,

Fig. 3b

a multipole comprising two electrode half-shells together with a holding device in a side view along the central longitudinal axis of the multipole,

Fig. 4

a side view of a multipole comprising two electrode half-shells together with a holding device on or attached to a receiving device,

Fig. 5

a frontal view of an empty assembly unit without multipole and holding device,

Fig. 6a,b

a side and a front view of the assembly unit with multipole and holding device,

Fig. 7a-d

several embodiments of a holding device,

Fig. 8a-d

Several embodiments of holes and bores brought into the holding device,

Fig. 9

the multipole according to Fig. 4 without a recording device, with exaggeratedly depicted, inaccurately crafted outer contours of the electrode half-shells and

Fig. 10

the multipole according to Fig. 9 without the in Fig. 9 The holding device shown according to the invention, however, with a conventional ring-shaped holding device to illustrate an undesirable offset of the common center point of the electrodes of the multipole relative to the center point of the outer contour of the electrode half-shells.

Identical reference numbers in the figures denote identical parts. Additional letters following a reference number denote further embodiments of the corresponding part.

Fig. 1a-d show a possible embodiment of a holding device 10 of a multipole according to the invention, as it is e.g. in Fig. 3a shown with reference number 32. In the Figures 1a-d However, only part 10a of the two-part holding device 10 is shown.

Fig. 1a Figure 1 shows a particularly preferred embodiment of the holding device 10a in a perspective view. It describes a U-shape, wherein two supports 12 form the parallel sides of the U-shape, and a support connection 14 forms the lower part of the U-shape, which connects the parallel sides of the U-shape and thus the supports 12. The supports 12 each have a bore 16 and a hole 18 as positioning means, as well as two through holes and/or threaded bores 20.

The surfaces of the supports 12 have a first support surface 13 and a second support surface 15, which are designed as highly precise, flat surfaces parallel to each other. Preferably, these support surfaces 13 and 15 are manufactured to ISO standard tolerances IT5 to IT11 with respect to their nominal dimensions. Furthermore, these support surfaces 13 and 15 also exhibit highly precise positional tolerances with respect to the parallelism of the two support surfaces 13 and 15 to each other, as well as with respect to the perpendicularity between the support surfaces 13 and 15 and the positioning means.

In this embodiment, the bore 16 is designed as a bore which serves for the subsequent precise positioning of the holding device 10a. Preferably, the bore 16 finds a corresponding counterpart in another component on which the holding device 10a is to be aligned and positioned, so that a pin, which is positively engaged in the radial direction of the bore 16 and fits into the bore 16, can be inserted through the bore 16 and the corresponding counterpart.

In this preferred embodiment, the hole 18 is designed as an elongated hole which has the same width as the diameter of the bore 16. The through and/or threaded bores 20 serve to fasten the holding device 10a to another component.

The preferred holding device 10a also has roof edge elements 22 with roof edge threaded bores 24. Each roof edge element 22 has two surfaces arranged at an angle to each other, a narrow roof edge flank 21 and a wide roof edge flank 23, each with the same slope. These roof edge flanks 21 and 23 are machined with high precision, preferably by grinding. The surface of the roof edge flank 23 of the holding device 10a, which is wider than the narrower roof edge flank 21, is connected to the first bearing surface 13 of the holding device 10a via a preferably angled side surface 19.

Fig. 1b shows a side view of the same preferred embodiment of the holding device 10a as in Fig. 1a This illustration highlights the design of bore 16, which is shaped as an elongated hole. The hole 18, the through and/or threaded bores 20, and the roof edge threaded bores 24 are distinguished. The roof edge flanks 21 and 23, arranged at an angle to each other, form the roof edge element 22. The roof edge element 22 has a roof edge threaded bore 24, by means of which the holding device 10a can be fastened to a corresponding further device by means of screws.

Fig. 1c shows a side view of the longitudinal side of the same holding device 10a as in Fig. 1a b. This illustration shows that the height or thickness of the supports 12 is a multiple of the height or thickness of the support connection 14. The height or thickness of a support 12 is defined by the distance between the first support surface 13 and the second support surface 15 of the holding device 10a.

The different thickness of the support connection 14 compared to the supports 12 advantageously saves material. Furthermore, the thinness of the support connection 14 advantageously allows for a certain degree of torsional movement. The support connection 14 serves to hold the supports 12 at a predetermined distance and position relative to each other. The bearing surfaces 13 and 15 of the supports 12 are precisely parallel to each other, so these surfaces must be machined with precision. These surfaces are preferably machined by milling and/or grinding.

Fig. 1d shows a side view transverse to the longitudinal direction of the same preferred holding device 10a as in Fig. 1a-c It can be seen here that the supports 12 are thicker than the height of the roof edge element 22, the height of which is determined by the distance from the support surface 15 to the vertex 25 of the roof-shaped side of the roof edge element 22. The roof edge flanks 21 and 23, arranged at an angle to each other, have a predetermined angle and an axis of symmetry, the axis of symmetry passing through the vertex 25 of the roof edge shape. This angle between the axis of symmetry of each of the roof edge flanks 21 and 23 of the roof edge element 22 is preferably 120°, more preferably 110°, and more preferably 130°.

The holding device according to the invention Figure 1a-d It is preferably manufactured from a single workpiece. This manufacturing is preferably carried out by milling. Surfaces requiring precise machining with high accuracy and/or low surface roughness are further processed by grinding.

Fig. 2a Figure 1 shows a perspective view of a support element or electrode half-shell 26 of a multipole with two electrodes arranged on the electrode half-shell 26. The blackened areas essentially represent hyperbolically shaped surfaces of these electrodes, which determine the field distribution within the quadrupole.

Furthermore, it shows Fig. 2a a holding device 10a, which is arranged on a support element or an electrode half-shell 26 of a multipole. As in Fig. 1a-d shows Fig. 2a A preferred embodiment of the holding device 10. Other embodiments of the holding device 10 are also applicable to the following explanations.

The electrode half-shell 26 has connecting elements designed as roof edge structures 28 and prism structures 30. The roof edge structures 28 and prism structures 30, as well as the roof edge element 22 of the holding device 10a, have the following features: Fig. 1a-d , two mutually angularly arranged surfaces with the same slope. On one side of the electrode half-shell 26, only roof edge structures 28 are arranged, and on the opposite side of the electrode half-shell 26, only prism structures 30 are arranged. The roof edge structures 28 and prism structures 30 are designed to correspond to each other such that one roof edge structure 28 and one prism structure 30 can be joined together to form a roof edge and prism connection 31. The prism structures 30 have a channel-shaped or convex form. The number of prism structures 30 is the sum of the number of manufactured roof edge structures 28 and the number of roof edge elements 22 of a holding device 10a to be attached to the electrode half-shell 26. The roof edge and prism connections 31 thus serve, firstly, to join two electrode half-shells 26 to form a multipole and, secondly, to attach a holding device 10a to an electrode half-shell 26, wherein a roof edge element 22 of the holding device 10a is inserted into a prism structure 30. The attachment of the holding device 10a to the electrode half-shell 26 via roof edge and prism connections 31 advantageously enables µm-accurate positioning of the holding device 10a relative to the center of the multipole, or to the central longitudinal axis of the multipole, and thus precise positioning of the multipole in a mass spectrometer.

Fig. 2b Figure 1 shows a side view of the electrode half-shell 26 with the preferred holding device 10a. The roof edge element 22 of the holding device 10a, due to its shape corresponding to the prism structure 30, can be inserted into the prism structure 30 of the electrode half-shell 26. According to the invention, the wide roof edge flank 23 of the roof edge element 22 is oriented towards the bearing surface 13 and is wider than the narrow roof edge flank 21 of the roof edge element 22. This results in the roof edge flank 23 projecting beyond the outer surface of the electrode half-shell 26 after the roof edge element 22 of the holding device 10a is inserted into the prism structures 30 of the electrode half-shell 26. This has the advantage of preventing the roof edge element 22 from tilting against the prism structure 30 and thus also prevents the holding device 10a from tilting against the electrode half-shell 26.

Fig. 2c shows a top view of an electrode half-shell 26 with the electrodes attached to the electrode half-shell 26 and a holding device 10a in the same embodiment as in Figs. 2a and 2b Here too, as in Fig. 2a The essentially hyperbolically shaped surfaces of the electrodes are shown in black.

In this top view, the supports 12 of the holding device 10a conceal the two further prism structures 30, which serve to fasten the holding device 10a. Thus, the same number of roof edge structures 28 and prism structures 30 are visible. The holding device 10a can be fastened to the electrode half-shell 26 by means of screws through connecting holes 29 in the prism structures 30 and via the roof edge threaded holes 24 in the holding device 10a. The roof edge structures 28 of the electrode half-shell 26 have connecting threaded bores 27, which are preferably designed in the same way as the roof edge threaded bores 24 of the holding device 10a.

Fig. 3a shows two electrode half-shells 26 joined together to form a multipole 32, each with a holding device 10a attached to it, according to the embodiment. Fig. 2a-c . Such a multipole 32 is preferably configured as a quadrupole. Fig. 3a Figure 1 shows such a preferred quadrupole, comprising two of the electrode half-shells 26, with a two-part holding device 10a. Each part of the holding device 10a is arranged and attached to the prism structures 30 laterally on each electrode half-shell 26 via the roof edge elements 22. The electrode half-shells 26 are connected to each other via the roof edge structures 28 and the prism structures 30, with each roof edge structure 28 being inserted into each prism structure 30. When inserted, each roof edge structure 28 and each prism structure 30 form a roof edge and prism connection 31. The roof edge and prism connections 31 can be fixed by means of screws 33. The wider design of the roof edge flanks 23, compared to the narrow roof edge flanks 21, advantageously serves to ensure a defined distance between the bearing surfaces 13 of the supports 12 and the roof edge and prism connections 31.

Fig. 3b shows a side view along the central longitudinal axis of the electrode half-shells 26 joined to form a multipole 32, each with a holding device 10a as in Fig. 3a The side view shows the connections of the joined electrode half-shells 26, designed as roof edge and prism connections 31. Thus, only one of the two attached holding devices 10a is visible in this view. The second holding device 10a is located directly behind the one shown in Fig. 3b visible holding device 10a. Each of the connections formed by a roof edge structure 28 and a prism structure 30, which are joined to form a roof edge and prism connection 31, is fixed with a screw 33. For this purpose, a connecting bore 29 is provided in each prism structure 30 and a connecting threaded bore 27 is provided in each roof edge structure 28. These connecting threaded bores 27 of the electrode half-shell 26 are preferably designed in the same way as the roof edge threaded bores 24 of the holding device 10a. Thus, the holding device 10a can advantageously be fixed to the electrode half-shells 26 via the prism structures 30 by means of the same screws 33 as the electrode half-shells 26 are fixed to each other.

The holding device 10a, attached to the electrode half-shell 26, has a mounting distance 34 to the other electrode half-shell. This allows the holding device 10a to be advantageously connected to the prism structures 30 even after the electrode half-shells 26 have been joined, whereby the holding device 10a is inserted into the prism structures 30 by means of lateral insertion along the alignment of the roof edge elements 22, which are aligned parallel to the longitudinal direction of the multipole 32.

Preferably, the holding device 10a has at least one roof edge structure 28 which can be connected to a correspondingly designed prism structure 30 of the electrode half-shell 26. Thus, it is advantageously possible to manufacture a holding device 10 using already known and existing tools for the production and machining of the electrode half-shells 26.

Fig. 4 Figure 1 shows a multipole 32 with a two-part holding device 10a, which is arranged on a receiving device 36. The holding device 10a, and thus the multipole 32, is connected to the receiving device 36 by means of fastening elements 38, in particular dowel pins. Such a receiving device 36 is, for example, arranged in a mass spectrometer.

These in Fig. 4 The view shown of the end face of the multipole 32 shows the arrangement of the holding device 10a in the receiving device 36 according to the invention, which is characterized by the following features:
The holding device 10a is arranged laterally to the multipole 32 in the region of a cylindrical surface enclosing the multipole 32, wherein the vertical extent or thickness of the supports 12 of the holding device 10a is advantageously dimensioned such that a plane which contains a straight line passing through the center of the circular cross-section of the multipole 32 is likewise a plane of symmetry of the cylindrical shape of the preferred multipole 32. Fig. 4 The holding device 10a is also divided into two parts of equal vertical extent or thickness. The advantageous design and arrangement of the holding device 10a on the multipole 32, in which the flat bearing surfaces 13, 15 of the supports 12 are arranged rotationally asymmetrically to the central longitudinal axis of the multipole 32, ensures that the multipole 32 is aligned parallel to a plane defined by the bearing surfaces of the supports 12 of the holding device 10a. The supports 12 of the holding device 10a can be arranged on or in a corresponding receiving device 36.

Fig. 5 Figure 1 shows a frontal view of a preferred assembly unit 40. The assembly unit 40 preferably comprises a base plate 42, a rear wall 44, and a receiving device 36a for a holding device 10a. Such an assembly unit 40 serves to mount the holding devices 10a according to the Figures 1a-d , 2a-c and 3a-b at a multipole 32 and, if applicable, the electrode half-shells 26 to each other.

The receiving device 36a according to the embodiment shown here has four receiving bores 46 and four receiving threaded bores 48. The receiving bores 46 and the receiving threaded bores 48 of the receiving device 36a are arranged such that they correspond to the arrangement of the bores 16, holes 18, and through and/or threaded bores 20 of the holding device 10a. Furthermore, the diameters of the bores 16 in the holding device 10a and the receiving bores 46 in the assembly unit 40, as well as the diameters of the through and/or threaded bores 20 in the holding device 10a and the receiving threaded bores 48 in the assembly unit 40, are the same. The rear wall 44 advantageously has recesses 50 which allow the insertion of a tool, preferably a screwdriver.

Fig. 6a shows a side view of the preferred mounting unit 40 according to Fig. 5 with a multipole 32 and a holding device 10a. The holding device 10a is connected to the receiving device 36a by means of at least two, preferably four, pins 38. This connection of the pins 38 through the bores The bores 16 in the holding device 10a and the receiving bores 46 of the receiving device 36a are designed to form a positive fit in the radial direction of the pins 38. Preferably, appropriately designed dowel pins are used to produce such a positive fit, which extend through the bores 16 in the holding device 10a and the receiving bores 46 in the receiving device 36a, which are designed as dowel bores.

Fig. 6b shows a frontal view of the same structure as in Fig. 6a , which comprises a mounting unit 40 with a receiving device 36a, a base plate 42, a rear wall 44 with recesses 50, and a multipole 32 with a holding device 10a, which is arranged on the mounting unit 40 by means of appropriately designed pins 38. The recesses 50 are formed by the arrangement of the multipole 32 in the mounting unit 40 in this view, which is shown in Fig. 6b The elongated holes 18 in the holding device 10a advantageously allow the holding device 10a to be locked or positioned on the receiving device 36a without tilting. The mounting unit enables the holding device 10a to be positioned relative to the multipole 32. This is done as follows:
The electrode half-shells 26 are already loosely connected to each other and to the holding device 10a. The holding device 10a is connected to the receiving unit 36a by means of at least two pins 38, each via a hole 18 and a bore 16. To secure this connection, fixing screws 52 can be inserted into the through-holes and/or threaded bores 20 of the holding device 10a and the through-holes and/or threaded bores 48 in the receiving unit 36a of the assembly 40.

Preferably, this fixing is achieved via a through-hole 20 with a corresponding receiving threaded hole 48 by means of a fixing screw 52. For fixing via a threaded hole 20 or a partially threaded hole with a corresponding receiving threaded hole 48, a thin-shank screw with a partial thread is used as a fixing screw 52, which only has a thread in the area of the receiving threaded hole 48.

Once the holding device 10a has reached a predetermined relative position to the multipole 32, it is fixed accordingly. In this preferred embodiment, this fixing is achieved by means of screws 33. For this purpose, the screws 33 are inserted through the connecting bores 29 of the electrode half-shells 26 into the connecting threaded bores 27 of the electrode half-shells 26 to fix the electrode half-shells 26 to one another.

To fix the holding device 10a to the electrode half-shell 26, the screws 33 are inserted through the connecting bores 29 of the electrode half-shells 26 into the roof-shaped threaded bores 24 of the holding device 10a. After fixing, the desired positioning of the holding device 10a relative to the multipole 32 is completed. Thus, the multipole 32 is aligned in a predetermined position in the mass spectrometer by means of the holding device 10a according to the invention and can be installed quickly and easily in the mass spectrometer.

The Figures 7a-d Figure 1 shows various embodiments of a holding device 10 according to the invention on a multipole 32, the list of embodiments being non-exhaustive:
Fig. 7a shows a multipole 32 with a two-part holding device 10a of the preferred embodiment, as described in the previous Figures 1a-d , 2a-c , 3a-b, 4 and 6a-b shown. Each of the two parts of the holding device 10a is preferably made from a single workpiece, in particular by milling. The holding device 10a describes a U-shape, wherein the mutually parallel sections of the U-shape form the supports 12, which are connected to each other and in a fixed relative position to each other by means of a support connection 14.

The supports 12 are thicker than the support connections 14. The supports 12 are manufactured in such a way that they provide highly precise, flat support surfaces 13 and 15. This requires precise manufacturing of the surfaces of the support surfaces 13 and 15 of the supports 12 with respect to the form and/or positional tolerances, in particular with an ISO basic tolerance of IT5 to IT11.

In a preferred embodiment, the surfaces of the support surfaces 13 and 15 are machined using machining processes such as sawing or milling. To meet the requirement of high precision in manufacturing, milling is preferably chosen for the support surfaces 13 and 15. The machining of the support connections 14 requires less precision compared to the support surfaces 13 and 15, as these primarily serve to ensure and define a fixed axial distance and a desired position of the supports 12 relative to each other.

In Fig. 7b A holding device 10b for holding a multipole 32, comprising a total of four parts, preferably identical to each other, is shown. Compared to a holding device 10a, such a holding device 10b does not have a support connection 14. The holding device 10b comprises four supports 12 without a support connection 14. This embodiment has the advantage that at least four of the parts of the holding devices 10b can be manufactured from a single piece of material of the same size as the piece of material from which two of the parts of the holding devices 10a were manufactured. This results in an advantageous material saving of 50-70% and thus also a reduction in labor costs.

Fig. 7c Figure 1 shows a further embodiment of a holding device 10 according to the invention for holding a multipole 32. In this case, the multipole 32 is connected to three parts of the holding device 10b, thereby achieving further material savings while ensuring a stable position of the multipole 32. However, this material saving results in the arrangement of the supports not being symmetrical with respect to an axis of symmetry that runs parallel to the central longitudinal axis of the multipole 32. Thus, the electrode half-shells 26 of the multipole 32 would each have to have a different number of roof edge and prism connections 31.

Fig. 7d Figure 1 shows a further embodiment of the holding device 10 according to the invention. In this case, the multipole 32 has two identically designed parts of a holding device 10c, which does not include any support connections 14. The parts of the holding device 10c are aligned centrally along the central longitudinal axis of the multipole 32 and attached to the electrode half-shells 26. The width or size of the supports 12 of the holding device 10c is designed such that a sufficient contact surface 13 and 15 for a stable position is ensured in each case. However, this embodiment of the holding device 10c requires very high precision in the manufacture of the contact surfaces 13 and 15, which results in higher manufacturing costs.

As an alternative to the explanations according to Fig. 7a-d A one-piece use of a holding device 10 according to one of the embodiments 10a-c is also possible. When mounted with only one one-piece holding device 10, this holding device 10a-c is preferably arranged vertically below the multipole 32 in the installation position of the multipole 32 in a mass spectrometer, in the direction of the central longitudinal axis of the multipole 32, in order to transmit as few vibrations as possible to the multipole 32.

The Fig. 8a-d Figure 1 shows several embodiments of the bores 16, holes 18 and through and/or threaded bores 20, which are incorporated into the preferred embodiment of the holding device 10a according to Figure 1. Fig. 1a-d The corresponding variants of the exemplary embodiments are indicated by adding apostrophes to the reference numeral 10a: e.g., ' for the first alternative variant, " for the second alternative variant, etc.

Fig. 8a Figure 1 shows the two parts of the holding device 10a, each with a slotted hole 18, a bore 16, and two through holes and/or threaded bores 20. The through holes and/or threaded bores 20 serve to fix the holding device 10a in the receiving device 36.

Fig. 8b shows the same geometric arrangement of holes 18 and bores 16 as in Fig. 8a In this first alternative embodiment, however, the through-holes and/or threaded bores 20 are missing. According to this embodiment, the fixing of the holding device 10a' to a receiving device 36 is thus achieved, for example, by means of a clamping fastener. Such a clamping fastener has the advantage that the multipole 32 attached to the holding device 10a', which is arranged, for example, in a mass spectrometer, can be replaced easily and quickly.

Fig. 8c Figure 1 shows a variant of the introduction of the holes 18 and bores 16 into the holding device 10a' and 10a". A hole 18, preferably an elongated hole, and a bore 16 are each provided in the holding device 10a', as shown in Figure 1. Fig. 8b The holding device 10a" in turn has neither a hole nor a bore. Thus, the multipole 32 is only secured and centered by means of one of the two holding devices 10a' and 10a".

Fig. 8d Figure 1 shows another variant, wherein the holding device 10a‴ has a hole 18, preferably designed as an elongated hole, and the second holding device 10a‴ has a bore 16. The hole 18 and the bore 16 are arranged relative to each other such that they lie on a diagonal with respect to the central longitudinal axis of the multipole 32.

The fixing of the holding device 10a' to 10aʺʺ to the receiving device 36 is carried out according to the Figs. 8c and 8d analogous to Fig. 8b by means of a clamping fastener. In the event, however, that fixing is achieved via at least one fixing screw 52, additional through holes and/or threaded holes 20 must be provided in the holding devices 10a' to 10aʺʺ, which, however, are in Figs. 8c and 8d are not shown.

In the Fig. 8a-d In the illustrated embodiments of the bores 16, holes 18 and through and/or threaded bores 20, these can also be combined for the use of a single fastening element 38, making it possible to use a dowel pin screw as a fastening element 38.

Fig. 9 shows the multipole 32 according to Fig. 4 without the in Fig. 4 The illustrated receiving device 36. The outer contours of the electrode half-shells 26 are shown with exaggerated inaccuracy. The two parts 10a of the holding device 10 are attached to surfaces of the prism structures 30, which are machined together in one operation with the electrodes 26A, 26B of an electrode half-shell 26. For this purpose, these electrodes 26A, 26B are first attached to half-shell elements 56 via insulators 54, e.g., by gluing. This machining is carried out, for example, with a single grinding wheel. Thus, a precise position of the machined surfaces of the electrodes 26A, 26B and the surfaces of the prism structures 30 relative to each other is ensured.

As a result of this precise arrangement of the surfaces of the prism structures 30, the parts 10a of the holding device 10 can also be aligned very precisely with the machined electrode surfaces. This enables an exact spacing of the dowel pin bores 16 from the center point M of the machined electrode surfaces. The multipole can thus be easily and precisely installed and aligned in the mass spectrometer.

Fig. 10 shows the multipole according to Fig. 9 without the in Fig. 9 The illustrated holding device according to the invention, however, uses a conventional ring-shaped holding device 58 to illustrate an undesirable offset X in the x-direction and Y in the y-direction of the common center point M of the machined electrode surfaces of the multipole 32 relative to the center point N of the outer contour of the electrode half-shells 26 and thus of the ring-shaped holding device 58 conventionally attached to this outer contour. Such an offset can be avoided thanks to the invention. The invention therefore contributes to significantly increasing the measurement accuracy of mass spectrometers.

Claims (13)

1. Device comprising a multipole (32) having two electrode half-shells (26) and electrodes (26A, 26B) arranged thereon, and a holding device (10) arranged on the multipole (32) for holding the multipole (32), for example a quadrupole in a mass spectrometer,

   wherein the holding device (10) has one or more flat support surfaces (13, 15) for attaching the multipole (32) to a receiving device (36, 36a) for receiving the holding device (10), and

   the holding device (10) is arranged on surfaces (30) of the electrode half-shells (26) of the multipole (32), which are produced together with electrode surfaces of the electrodes (26A, 26B) of the multipole in a work step by joint grinding with the same grinding stone in such a way that these surfaces (30) have a clear and exact geometric relationship to the electrode surfaces ground in this way.
2. Device according to claim 1, characterized in that the holding device (10) is arranged laterally to a cylinder surface enveloping the multipole (32).
3. Device according to claim 2, characterized in that the holding device (10) is arranged in a central section of the enveloping cylinder surface, wherein this central section is symmetrical to the central transverse axis of the multipole (32) and corresponds to a maximum of 90% of the cylinder surface.
4. Device according to one of the preceding claims, characterized in that the holding device (10) has one or more positioning means and
   the holding device (10) can be aligned on the receiving device (36, 36a) by means of these positioning means.
5. Device according to claim 4, characterized in that at least one positioning means of the holding device (10) is formed by a hole (18) and/or a bore (16) in the holding device (10) and
   the holding device (10) is connected to the receiving device (36, 36a) by means of a fastening element (38) with a radial extension, for example a dowel pin or dowel screw, which is suitably designed for the hole (18) and/or the bore (16) in the radial direction of the fastening element (38), wherein the arrangement of the at least one positioning means in the holding device (10) corresponds to the arrangement of at least one receiving element, for example a receiving bore (46), in the receiving device (36, 36a).
6. Device according to claim 5, characterized in that the holding device (10) has at least one hole (18) which is designed as a slotted hole, wherein the width of the slotted hole in the holding device (10) is equal to the diameter of the correspondingly arranged receiving bore (46) in the receiving device (36, 36a) and is equal to the diameter of the at least one bore (16) in the holding device (10).
7. Device according to one of the preceding claims, characterized in that the holding device (10) can be connected to the multipole (32) via roof edge and prism connections (31) and the multipole (32) can be dismantled along its central longitudinal axis into at least two parts, of which the two electrode half-shells (26), which can also be joined together via roof edge and prism connections (31), wherein each roof edge and prism connection (31) has either a roof edge structure (28) and a prism structure (30) on the electrode half-shells (26) or a roof edge element (22) on the holding device (10) and a prism structure (30) on the electrode half-shells (26), which are designed to correspond to each other, in that the roof edge structure (28) or the roof edge element (22) is roof-shaped and the prism structure (30) is channel-shaped, whereby the roof edge structures (28) or roof edge elements (22) being aligned with each other and the prism structures (30) being aligned with each other with respect to a parallel running parallel to the central longitudinal axis of the multipole (32), and each roof edge structure (28) or roof edge element (22) being able to be joined together with a prism structure (30).
8. Device according to one of the preceding claims, characterized in that the holding device (10) has through holes and/or threaded holes (20), wherein the through holes and/or threaded holes (20) of the holding device (10) are arranged to correspond to receiving threaded holes (48) of the receiving device (36, 36a).
9. Device according to one of the preceding claims, wherein the holding device (10) can be arranged on a receiving device (36, 36a) of a mass spectrometer, a mounting unit (40) and/or a unit serving to maintain the multipole (32), and
   the holding device (10) has at least one roof edge structure (28) and/or at least one prism structure (30) for fastening to the multipole (32).
10. Mass spectrometer with a device according to one of claims 1 to 9 and a receiving device (36) for receiving the holding device (10) of the device, in particular according to claim 9, wherein by means of the holding device (10) of the multipole (32), this multipole (32) is arranged in an exact geometric position in relation to all axis directions of the multipole (32) and relative to other components of the mass spectrometer in the mass spectrometer.
11. Mounting unit with a receiving device (36a) designed and adapted for positioning the holding device (10) relative to the multipole (32) of a device according to one of claims 1 to 9, wherein the mounting unit (40) has a base plate (42) which, in use, is aligned in such a way that the central longitudinal axis of a multipole (32) arranged on the receiving device (36a) of the mounting unit (40) and the direction of action of gravity are aligned perpendicular to the base plate (42), and wherein the mounting unit (40) has a rear wall (44) which has recesses (50), for example hole-shaped recesses, which are arranged in such a way that connecting elements of the holding device (10) with the multipole (32) and/or the electrode half-shells (26) of the multipole (32) are visible through them and accessible with a tool.
12. Method for positioning the holding device (10) relative to the multipole (32) of a device according to one of claims 1 to 9 by means of an mounting unit (40) according to claim 11, comprising the following steps:

    - positively connecting the holding device (10) to the associated receiving device (36a),

    - moving the multipole (32) relative to the holding device (10) in the longitudinal direction of the multipole (32) until a predetermined relative position of the multipole (32) to the holding device (10) is reached, and

    - fixing this relative position, for example by means of screwing, clamping, jamming, gluing, stapling, welding, and/or soldering.
13. Method according to claim 12, characterized in that the form-fitting connection of the holding device (10) to the receiving device (36a) is achieved by means of at least two positioning means, for example, dowel pins or dowel pin screws, wherein each positioning means is inserted into a respective receptacle, for example, a receiving bore (46), hole (18) and/or bore (16).