Improved electrode arrangement

Abstract

Electrode arrangement (10, 10') for an ion trap, an ion filter, an ion guide, a reaction cell or an ion analyzer, the electrode arrangement (10, 10') comprising: an RF electrode (12a, 12b, 12a', 12b') mechanically connected to a dielectric material (11); wherein the RF electrode (12a, 12b, 12a', 12b') is mechanically connected to the dielectric material (11) by a plurality of separators (13, 13') that are spaced apart from one another and configured to define a gap between the RF electrode (12a, 12b, 12a', 12b') and the dielectric material (11), and wherein each of the plurality of separators (13, 13') comprises a projecting region (13b), and the dielectric material (11) comprises corresponding receiving regions (11a), such that when connecting the RF electrode to the dielectric material (11), the projecting region (13b) of each separator (13, 13') is received in the corresponding receiving region (11a) of the dielectric material (11), wherein the RF electrode (12a, 12b, 12a', 12b') has a surface opposite the dielectric material (11), wherein the electrode arrangement (10, 10') comprises at least one DC voltage electrode (14),which is positioned between the dielectric material (11) and the RF electrode (12a, 12b, 12a', 12b'), characterized in that , the DC electrode (14) extends over the dielectric material (11) such that at least a portion of the DC electrode (14) is located directly between the surface of the RF electrode (12a, 12b, 12a', 12b') and the dielectric material (11); and wherein the proportion of the surface area of ​​the surface of the RF electrode (12a, 12b, 12a', 12b') which is shielded from the dielectric material (11) by the DC voltage electrode (14) is at least 50%.

Description

Field of the invention

[0001] This invention relates to an improved electrode arrangement for an ion guide, an ion filter, an ion trap, an ion storage device, an ion reaction cell, in particular for an ion collision cell or an ion analyzer, in particular a mass analyzer. background

[0002] Mass spectrometry is an important technique for the analysis of chemical and biological samples. A mass spectrometer generally comprises an ion source for generating ions from a sample, various lenses, ion guides, mass filters, ion traps / storage devices, and / or one or more reaction cells, as well as one or more mass analyzers.

[0003] A reaction cell can be a collision and / or fragmentation cell. The reaction in the reaction cell can be an electron capture dissociation, a higher-energy collision dissociation (HCD), an electron transfer dissociation, an oxidation, a hybridization, a clustering, or a complex reaction. The reaction cell can comprise a quadrupole, a hexapole, an octopole, or a higher-order multipole.

[0004] Known electrode assemblies for ion guides, ion traps / storage devices, and reaction cells typically comprise RF electrodes for radially confining the ions and DC electrodes for moving the ions along an axis of the ion guide / ion trap / storage device / reaction cell. Such an electrode assembly may comprise RF electrodes in the form of rods with a circular or hyperbolic cross-section, arranged to form a multipole or mass filter. These electrodes may be arranged on dielectric spacers, as presented in GB 2 554 626 A1, US 5,616,919 A, US 7,348,552 B2. The electrode assembly may also comprise DC electrodes configured to provide a DC field along the axis of the ion guide, ion trap, storage device, or reaction cell.

[0005] To simplify the fabrication of electrode assemblies for ion guides, planar configurations have been designed, as discussed, for example, in US Pat. No. 9,536,722 B2. Planar configurations also offer greater flexibility for the design of the DC field. Such planar configurations can be implemented using printed circuit boards (PCBs) to which planar RF and DC electrodes are connected. The PCBs are formed from a non-conductive material, usually a dielectric material, which may be reinforced, such as with glass fibers. Typically, the planar RF electrodes extend axially along the length of the ion guide in an arrangement forming an RF multipole. The DC electrodes also extend axially along the length of the ion guide, forming a DC field along their axis.The planar RF electrodes can be attached to the surface of a printed circuit board (PCB) using adhesive or soldering. A spacer made of the PCB's dielectric material can be provided along the length of the planar RF electrode between the PCB and the RF electrode. The DC electrodes can be etched onto the PCB surface. Typically, the DC electrodes are provided on areas of the PCB surface adjacent to the RF electrodes, so that the DC electrodes are separated from the RF electrodes by the dielectric (PCB) material.

[0006] However, as a result of such a planar construction, the RF field generated by the RF electrodes penetrates the PCB's dielectric material in areas unshielded by the DC electrodes. This penetration causes heating of the PCB through dielectric loss. In particular, the RF field penetrating the PCB material causes energy to be dissipated as the molecules of the dielectric (PCB) material attempt to align with the continuously changing RF field. This dielectric loss is described by the loss factor Df, which is discussed further in the detailed description. Heating of the PCB causes PCB material to evaporate (outgassing). The adhesive used to attach the RF electrode(s) to the PCB may also evaporate. The evaporated material (and the adhesive) can contaminate the ions contained in the ion guide.These contaminants can be carried by the spectrometer to the detector, thus generating peaks corresponding to the contaminants in the resulting mass spectra. The contaminants can also cause undesirable changes to the analyte contained in the ion guide. For example, the contaminants can combine with the analyte molecules, forming adducts, and / or react with the analyte molecules, releasing some of their charge (charge reduction). Both of these undesirable changes to the analyte produce spurious peaks in the resulting mass spectra. The ion guide / ion trap / storage device / collision cell can also contain a buffer gas. The heat generated in the dielectric (LP) material can provide sufficient energy to the buffer gas molecules, causing reactions of the analyte with the buffer gas molecules.For example, buffer gas molecules can react and combine with analyte molecules to form adducts. The reaction of buffer gas molecules with analyte molecules can also reduce the charge on the analyte molecules. Consequently, these reactions cause undesirable changes to the analyte molecules. In collision cells, ions are confined for longer periods of time (e.g., a number of milliseconds) and are exposed to stronger RF fields compared to ion guides. In fact, collision cells typically operate at RF voltages of 1200–1500 V, which are much higher than ion guides, which typically operate at less than 1000 V. Accordingly, the heating of the LPn and the resulting undesirable effects are particularly noticeable for collision cells.

[0007] Fig. Figure 1 is a schematic diagram of a known electrode assembly 1 having known first and second electrode assemblies 2, 2'. The first and second electrode assemblies 2, 2' include planar RF electrodes 3 extending in the longitudinal direction. The RF electrodes are attached to dielectric materials 4 by a conductive adhesive provided along the length of the planar RF electrodes 3. The planar RF electrodes 3 are held in alignment by grooves 5 extending in the longitudinal direction, thereby forming an assembly. The DC electrodes 6 are provided on the surface of the dielectric material 4 on each side of the planar RF electrodes 3.

[0008] Fig. Figure 1a shows a cross-section of the RF electrodes 3 of the known electrode assembly 1. Grooves 5 are provided around the RF electrodes to extend the creepage distance to the DC electrodes. In this assembly, the dielectric (LP) material 4 is embedded in a carrier.

[0009] The results of an experiment, referred to herein as Experiment 1, concerning an isolated charge state (+11) of multiply charged ubiquitin ions stored for 500 ms in a HCD (higher energy collision dissociation) cell with the known Fig. 1 shown electrode assembly 1 are shown in the Fig. 2 to 4. In the experiment, at time 0:00 (0 hours, 0 minutes), a high RF voltage (approximately 1250 Vpp) was applied to the RF electrodes 3 of the HCD cell for a period of 1:12 (1 hour and 12 minutes). The isolated and captured ubiquitin ions were then transferred from the HCD cell to a C-trap and injected from the C-trap into an Orbitrap™ mass analyzer for mass analysis. A C-trap is a curved linear ion trap that stores ion packets over time and then accelerates the ion packets into a mass analyzer, as described, for example, in patent applications WO 2002 / 078046 A2, WO 2008 / 081334 A2, and WO 2005 / 124821 A2. An RF voltage of approximately 3000 Vpp was applied to the RF electrodes of the C-trap adjacent to the HCD cell.

[0010] Two temperature sensors (e.g., platinum resistors with 100 ohms resistance at room temperature, hereinafter referred to as PT100) were used in this experiment. The first temperature sensor (PT100) was positioned on the dielectric material 4 of the HCD cell's PCB, to which the planar RF electrodes 3 were attached. The first temperature sensor and the RF electrode were arranged at the same position in the plane of the dielectric material 4, except that the temperature sensor was mounted on the surface of the dielectric material 4 opposite the RF electrodes 3. Accordingly, the RF electrode 3 and the first temperature sensor were separated only by the thickness of the dielectric material 4.By positioning the first temperature sensor close to the RF electrodes 3, the temperature measured by the first temperature sensor provided accurate results regarding the heating of the dielectric material 4 due to the penetration of the RF field generated by the RF electrodes 3.

[0011] The second temperature sensor (OT block PT100) was not placed in the HCD cell. Instead, the second temperature sensor was positioned inside the Orbitrap mass analyzer housing, close to the HCD cell. Accordingly, the second temperature sensor provides additional information regarding the increase in the temperature of the Orbitrap mass analyzer caused by the HCD cell's RF field.

[0012] Fig. Figure 2 is a graphical representation of the extracted ion current per charge state and the temperature of the HCD cell versus time over the course of Experiment 1. As in Fig. As shown in Figure 2, after applying the maximum RF voltage to the HCD cell for 1 hour and 12 minutes, the extracted ion current for the isolated charge state (+11), measured by the Orbitrap mass analyzer, decreased from approximately 19 arbitrary units / s to approximately 5 arbitrary units / s. Correspondingly, the intensity of the isolated charge state (+11) decreased approximately 4-fold over the course of the experiment. The extracted ion current for the charge state (+10), measured by the Orbitrap mass analyzer, increased from 2 arbitrary units / s to 6.25 arbitrary units / s. The extracted ion current for the isotope (+9), measured by the Orbitrap mass analyzer, increased from 0 arbitrary units / s to 3.75 arbitrary units / s. Correspondingly, the ion intensity of the reduced charge states increased significantly with a reduced charge over the course of the experiment.After applying the maximum RF voltage for 1 hour and 12 minutes, the total ion current of the reduced charge states was approximately 5 arbitrary units / s, and the total ion current of the isolated charge states (+11) was approximately 4 arbitrary units / s. Charge reduction is defined as the ratio of the sum of the extracted ion current from all peaks except those of the isolated charge states (+11) to that of the isolated charge states (+11). Accordingly, the charge reduction exceeded 100% when the maximum RF voltage was applied to the HCD cell for 1 hour and 12 minutes. After applying the maximum RF voltage to the HCD cell for 1 hour and 12 minutes, the temperature of the HCD cell was measured by the first temperature sensor and found to have increased by 20°C.It is understood that this increase in the temperature of the HCD cell caused an increased desorption and evaporation rate of the adhesive and dielectric (LP) material 4 in the electrode assembly 1. This consequently led to increased contamination of the HCD cell and increased charge reduction.

[0013] Fig. Figure 3(a) is a figure of the mass spectrum obtained at the beginning of Experiment 1, i.e., at the beginning of the application of the maximum RF voltage to the HCD cell (at time 0:00). As in Fig. As shown in Figure 3(a), the relative abundance of the isolated major isotope with the charge state (+11) at m / z 777.966 at time 0:00 is 100%, and the relative abundance of each of the other isotopes is less than 5%. The relative abundance of an isotope is given by the ratio of the abundance of that isotope to the abundance of the highest-abundant isotope (the isotope with 100% abundance). Fig. Figure 3(b) is a figure of the mass spectrum obtained at the end of Experiment 1 when the maximum RF voltage was applied for 1 hour and 12 minutes. When comparing the Fig. 3(a) and Fig. 3(b) shows that over the course of the experiment, the relative abundance of the isolated major isotope with the charge state (+11) decreased from 100% to 80%. The relative abundances of the other (non-isolated) reduced charge states increased significantly. For example, the relative abundance of the major isotope with the charge state (+9) is 50%, and the relative abundance of the major isotope with the charge state (+10) is 100%. Accordingly, a significant charge reduction occurred over the course of Experiment 1.

[0014] Fig. 4 is an infrared photograph of the known HCD cell with the electrode assembly 1 of Fig. 1. The image is taken from above relative to the HCD cell, so that the longitudinal direction of the electrode assembly 1 extends from top to bottom in the photograph. This photograph was taken 10 minutes after the HCD cell was turned off, following the completion of Experiment 1. At the time of this photograph, the pressure of the HCD cell was in equilibrium with atmospheric pressure. This photograph shows that the region of the HCD cell with the highest temperature (the part with the lightest color) is where the planar RF electrodes 3 are bonded to the dielectric material 4. Heating of the HCD cell occurs particularly when high-amplitude RF voltages are applied to the RF electrodes 3, which is the case in Experiment 1.

[0015] DE 11 2013 004 733 T5 relates to an ion conductor for use in mass spectrometry, wherein at least some of the exposed surface of a dielectric between the electrodes has one or more electrodes projecting beyond it and not in electrical contact with it. US 2005 / 0 258 364 A1 relates to the optimization of ion transport while simultaneously reducing gas flow between vacuum stages in mass spectrometry.

[0016] It would be desirable to provide an electrode assembly comprising a PCB with attached RF electrodes that can operate without significant heat generation, thereby minimizing outgassing and unwanted changes to analyte molecules, particularly when high-amplitude RF voltages are applied to the RF electrodes 3. Indeed, by providing such an electrode assembly, it would be possible for the first time to obtain a reliable collision cell, such as an HCD cell with an electrode assembly comprising a PCB with attached RF electrodes.

[0017] Another challenge with known electrode assemblies with LPs is ensuring precise manufacturing. Therefore, it would also be desirable to obtain a method for manufacturing electrode assemblies comprising LPs with attached RF electrodes with a higher level of precision than standard LP manufacturing processes. Summary

[0018] According to a first aspect of the present invention, an electrode assembly for an ion trap, an ion filter, an ion guide, a reaction cell, or an ion analyzer is provided, the electrode assembly comprising an RF electrode mechanically connected to a dielectric material, the RF electrode being mechanically connected to the dielectric material by a plurality of separators spaced apart from one another and configured to define a gap between the RF electrode and the dielectric material, and each of the plurality of separators comprising a protruding portion, and the dielectric material comprising corresponding receiving portions such that upon connecting the RF electrode to the dielectric material, the protruding portion of each separator is received in the corresponding receiving portion of the dielectric material.The plurality of separators may include pin separators, receptacled separators, or protruding separators, as described below, or a combination thereof.

[0019] The electrode assembly according to claim 1 comprises an RF electrode mechanically connected to a dielectric material. The RF electrode is connected to the dielectric material by a plurality of separators that are spaced apart from one another and configured to define a gap between the RF electrode and the dielectric material. By providing the gap between the RF electrode and the dielectric material, penetration of the strong RF field into the dielectric material close to the RF electrodes in this region is prevented.

[0020] Each of the plurality of separators includes a protruding portion, and the dielectric material includes a corresponding receiving portion or portions. The protruding portion of each separator is received within the corresponding receiving portion of the dielectric material. Bonding of the dielectric material is virtually limited to this connection. Each corresponding receiving portion or portions may have a shape complementary to the protruding portion of the separator or separators, thereby accommodating the protruding portion.

[0021] Furthermore, a DC electrode positioned between the dielectric material and the RF electrode shields the dielectric material from the RF field generated by the RF electrode. This shield prevents the RF field from penetrating the dielectric material, thus preventing heat generation in the dielectric material through dielectric loss. The only penetration of the RF field into the dielectric material occurs at the contact points between each separator and the dielectric material.

[0022] Using a plurality of separators to create the gap is advantageous because a gap of constant height can be achieved with minimal contact areas between the RF electrode and the dielectric material. Indeed, by using a plurality of spaced-apart separators, a DC electrode, and thus a DC field, can cover and shield most of the area of ​​the dielectric material directly above or below the RF electrode.

[0023] This contrasts with known electrode arrangements, where it is not possible for a DC electrode to extend along most of the dielectric surface directly above or below the RF electrode. Indeed, in known electrode arrangements, most of the dielectric surface directly above or below the RF electrode is covered with adhesive, solder, or a spacer.

[0024] Furthermore, in known arrangements, such as those described in US Pat. No. 7,348,552 B2, a spacer made of dielectric material is typically positioned between the surface of the PCB and the RF electrode to provide a gap between the PCB and the RF electrode, and correspondingly between the DC electrodes arranged on the surface of the PCB and the RF electrode. However, the dielectric material of the spacer, which is located very close to the RF electrodes, is heated by the RF field of the RF electrodes. This heating causes problems of contamination and charge reduction in an ion guide, ion filter, ion analyzer, ion trap, or reaction cell that include the electrode arrangement.

[0025] Accordingly, operation of the electrode assembly of the claimed invention results in significantly reduced heat generation and, consequently, reduced outgassing (evaporation of the dielectric (LP) material). Therefore, fewer contaminants are generated, and fewer undesirable changes to the analyte occur. Consequently, fewer false peaks are generated in the resulting mass spectra.

[0026] Preferably, the electrode assembly comprises at least one DC electrode positioned between the dielectric material and the RF electrode. As discussed above, the DC electrode, and thus the DC field, can cover and shield most of the area of ​​the dielectric material located directly above or below the RF electrode. This shielding prevents the RF field from penetrating the dielectric material, thus preventing the generation of heat in the dielectric material through dielectric loss. The only penetration of the RF field into the dielectric material occurs at the contact points between each separator and the dielectric material.

[0027] Preferably, the RF electrode has a surface opposite the dielectric material, and the DC electrode extends across the dielectric material such that at least a portion of the DC electrode is located directly between the surface of the RF electrode and the dielectric material. The proportion of the surface area of ​​the RF electrode that is shielded from the dielectric material by the DC electrode is at least 50%, preferably 80%, and most preferably 95%. The term "shielding" refers to a significant reduction (by at least an order of magnitude) in the electric field flux generated by a charged electrode at a given point due to the introduction of a shield. In the present invention, the RF field generated by the RF electrode is shielded by using a DC electrode as a shield.By placing a portion of the DC electrode directly between the surface of the RF electrode and the dielectric material, shielding is provided in the area of ​​the dielectric material that would otherwise be exposed to the strongest RF field. Accordingly, penetration of the RF field and heat generation in the dielectric material are minimized.

[0028] Preferably, in the claimed invention, the majority of separators are electrically conductive, and more preferably metallic. Then, the RF field of the RF electrodes only penetrates the dielectric material around the separators. However, this is a very limited area of ​​the RF electrodes. The separators generally create a gap between the RF electrodes and the dielectric material, which is preferably shielded by a DC electrode. This contrasts with known spacers, as discussed above, which are formed from a dielectric material with dielectric losses. These spacers are formed over the entire area of ​​the RF electrodes, close to the RF electrodes, and are therefore penetrated (and heated) by their RF field.

[0029] According to a second aspect of the present invention, an ion guide is provided comprising the electrode arrangement according to one of claims 1 to 25.

[0030] According to a third aspect of the present invention, an ion filter is provided comprising the electrode arrangement according to any one of claims 1 to 25.

[0031] According to a fourth aspect of the present invention, there is provided an ion analyzer comprising the electrode assembly according to any one of claims 1 to 25.

[0032] According to a fifth aspect of the present invention, there is provided an ion trap comprising the electrode arrangement according to any one of claims 1 to 25.

[0033] According to a sixth aspect of the present invention, there is provided a reaction cell comprising the electrode assembly according to any one of claims 1 to 25.

[0034] According to a seventh aspect of the present invention, a method for manufacturing the electrode assembly according to claims 1 to 25 is provided. Short description of the drawings

[0035] The invention may be practiced in a number of ways, and some specific embodiments will now be described by way of example only and with reference to the accompanying drawings. In the drawings: Fig. 1 is a schematic diagram of a known electrode assembly, the known electrode assembly comprising a first and a second known electrode arrangement, Fig. 1a a cross-section of the known electrode assembly of Fig. 1, Fig. 2 is a prior art graphical representation of the extracted ion current per charge state and the temperature of an HCD cell with the electrode assembly of Fig. 1 versus time over the course of Experiment 1, Fig. 3(a) a state-of-the-art mass spectrum obtained at the beginning of Experiment 1 (at time 0:00), Fig. 3(b) a state-of-the-art mass spectrum obtained at the end of Experiment 1 (at time 1:12), Fig. 4 is a prior art infrared photograph of an HCD cell with the electrode assembly of Fig. 1, Fig. 5 is a schematic diagram in perspective view of an electrode assembly with a first and a second electrode arrangement according to an embodiment of the present invention, Fig. 5a an enlarged view of Fig. 5, Fig. 6 is a schematic diagram of a longitudinal section of the electrode assembly of Fig. 5 according to an embodiment of the present invention, Fig. 7 is a schematic diagram of an exploded view of the first electrode assembly of the Fig. 5 and Fig. 6 according to an embodiment of the present invention, Fig. 8 is a schematic diagram of a cross-section of the electrode assembly of the Fig. 5 to 7 according to an embodiment of the present invention, Fig. 9 is a schematic diagram of a portion of a longitudinal section of the electrode assembly of the Fig. 5 to 8 according to an embodiment of the present invention, Fig. 10 is a schematic diagram of an exploded view of the electrode assembly of the Fig. 5 to 9 according to an embodiment of the present invention, Fig. 10a a cross-section of the electrode assembly of the Fig. 5 to 10 along the line AA' in Fig. 10, Fig. 10b shows a cross section of the electrode assembly of the Fig. 5 to 10 along the line BB' in Fig. 10, Fig. 11 a graphical representation of the ion current per charge state of an HCD cell with the electrode assembly of the Fig. 5 to 10 versus time over the course of Experiment 2, Fig. 12 a graphical representation of the data from Fig. 11, where the extracted ion current was normalized by the extracted ion current of the isotope with the charge state (+11) at each time point, Fig. 13 a graphical representation of charge reduction versus time for Experiment 2, Fig. 14(a) a mass spectrum obtained at the beginning of Experiment 2 (at time 0:00), Fig. 14(b) a mass spectrum obtained at the end of Experiment 2 (time 2:30), Fig. 15 is a schematic diagram of a second embodiment of the first electrode arrangement, Fig. 16 is a schematic diagram of a portion of a longitudinal section of the first electrode assembly of Fig. 15 according to the second embodiment of the present invention. Detailed description

[0036] In this specification, the term RF electrode refers to an electrode connected to an RF power supply. The term DC electrode refers to an electrode connected to a DC power supply. The term "inner" in reference to a surface refers to the surface facing the center of the electrode assembly 100. The term "outer" in reference to a surface refers to the surface facing away from the center of the electrode assembly 100.

[0037] Fig. Figure 5 is a schematic diagram of a perspective view of an electrode assembly 100 according to the present invention. The longitudinal axis of the electrode assembly 100 defines the longitudinal direction. The electrode assembly 100 extends in the longitudinal direction from a first end 100a to a second end 100b. The first and second ends 100a, 100b of the electrode assembly 100 are open / exposed for the passage of ions.

[0038] The electrode assembly 100 comprises a first and a second electrode arrangement 10, 10' extending in the longitudinal direction from the first end 100a to the second end 100b. In fact, the term "electrode assembly" refers to an electrode assembly, such as that according to claim 20, which comprises both a first and a second electrode arrangement 10, 10'. The first and the second electrode arrangement 10, 10' are spaced apart from each other and arranged in parallel, such that the first and the second electrode arrangement are substantially mirror images of each other, wherein the axis of symmetry corresponds to the central longitudinal axis of the electrode assembly 100. The first and the second electrode arrangement 10, 10' are spaced apart by first and second smaller side walls 101, 102. In fact, as in Fig. 5, the second electrode assembly 10' is supported above the first electrode assembly 10 by the first and second smaller sidewalls 101, 102. The first and second smaller sidewalls 101, 102 are arranged parallel to each other and extend along the major edges of the electrode assembly 100. In the present disclosure, the term "smaller" is used to indicate a smaller dimension (e.g., area or length), and the term "larger" is used to indicate a larger dimension. The smaller sidewalls include connecting elements 103, such as nuts and bolts, configured to provide a mechanical connection between the first and second electrode assemblies 10, 10'.

[0039] As in Fig. 5, each electrode assembly 10, 10' includes a dielectric material 11 forming a printed circuit board (PCB) configured to establish electrical connection with the components of the electrode assemblies 10, 10'. The dielectric materials 11 are planar (i.e., their length and width dimensions, which are parallel to the planar dielectric surface, are greater than their thickness dimension). The first and second electrode assemblies 10, 10' are arranged such that the planes of the planar dielectric material 11 of each electrode assembly 10, 10' are parallel to and face each other. Each dielectric material 11 has an inner major surface facing the center of the electrode assembly 100. Each dielectric material 11 has an outer major surface facing away from the center of the electrode assembly 100.The dielectric material 11 extends across the entire width of the electrode assembly 100 (in the transverse direction) and between the first and second ends 100a, 100b of the electrode assembly 100 (in the longitudinal direction). Accordingly, the dielectric material 11 also extends across the entire width of each electrode arrangement 10, 10'. The dielectric material 11 is preferably formed from megtron 6 due to its low dielectric losses.

[0040] How best in Fig. As shown in Figure 5, each electrode assembly 10, 10' includes first and second RF electrodes 12a, 12b, 12a', 12b' attached to the inner major surface of the dielectric material 11. The RF electrodes 12a, 12b, 12a', 12b' are elongated and extend in the longitudinal direction of each electrode assembly 10, 10' from the first end 100a to the second end 100b. In fact, the RF electrodes 12a, 12b, 12a', 12b' extend over the entire length of the dielectric material 11. The RF electrodes 12a, 12b, 12a', 12b' are planar (i.e., their length and width dimensions, which are arranged parallel to the planar dielectric surface, are greater than their thickness dimension, which is orthogonal to the planar dielectric surface). The RF electrodes 12a, 12b of the first electrode arrangement 10 are arranged parallel, facing the RF electrodes 12a', 12b' of the second electrode arrangement 10', and spaced apart from them.In each electrode assembly 10, 10', the first RF electrode 12a, 12b is spaced apart from the second RF electrode 12a', 12b'. The RF electrodes 12a, 12b, 12a', 12b' are electrically conductive. The RF electrodes 12a, 12b, 12a', 12b' are metallic, typically made of stainless steel or nickel.

[0041] In the Fig. 5 to 10, each RF electrode 12a, 12b, 12a', 12b' is mechanically connected to its respective dielectric material 11 by a plurality of (at least two) pin separators 13 that are spaced apart from each other. The pin separators 13 are preferably equally spaced. The pin separators 13 are configured to define a gap between the RF electrode and the dielectric material 11. The gap is directed in the direction orthogonal to the plane of the dielectric material 11. The pin separators 13 are electrically conductive and typically formed of copper or the same material as the RF electrodes. In the embodiment of Fig. 5 to 10 and how best in Fig. 6, each RF electrode 12a, 12b, 12a', 12b' is connected to the dielectric material 11 by four pin separators 13.

[0042] Each pin separator 13 is attached to a larger (planar) surface of the RF electrode 12a, 12b, 12a', 12b'. Preferably, the pin separator 13 is permanently attached to the surface of the RF electrode 12a, 12b, 12a', 12b'. Typically, the pin separator 13 is attached to the surface of the RF electrode by welding. Each pin separator 13 includes a head portion 13a and a protruding region 13b.

[0043] The head portion 13a is attached to the outer larger surface of the RF electrode 12a, 12b, 12a', 12b' (the planar surface of the RF electrode 12a, 12b, 12a', 12b' that is arranged close to and opposite the respective dielectric material 11) such that a protruding region 13b extends from the head portion 13a in a direction orthogonal to the plane of the RF electrode 12a, 12b, 12a', 12b' and orthogonal to the plane of the dielectric material 11. The head portion 13a has at least one electrical contact with the RF electrode 12a, 12b, 12a', 12b'.

[0044] The dielectric material 11 has a corresponding receiving area 11a, which is configured to receive the protruding area when connecting the RF electrode 12a, 12b, 12a', 12b' to the dielectric material 11. In the Fig. 5 to 10 shown embodiment and as best shown in Fig. As shown in Figures 7 to 10, the corresponding receiving portion 11a is a through-hole extending through the thickness of the dielectric material 11. The diameter of the protruding portion 13b is designed such that the protruding portion 13b is received and held in the through-hole 11a. The diameter of the head portion 13a is preferably larger than that of the through-holes 11a, so that the head portion 13a bears against the dielectric material 11 when the RF electrode 12a, 12b, 12a', 12b' is connected to the dielectric material 11. The head portion 13a is preferably planar, with its thickness dimension oriented orthogonal to the plane of the RF electrode 12a, 12b, 12a', 12b'. The height of the gap between the RF electrode 12a, 12b, 12a', 12b' and the dielectric material 11 to which it is mechanically connected is mainly determined by the thickness of the head portion 13a. In fact, as shown in the Fig. 8 and Fig. 9, the height of the gap between the RF electrode 12a, 12b, 12a', 12b' and their respective dielectric material 11 is approximately equal to the thickness of the head portion 13a. Accordingly, by providing at least two such pin separators 13 spaced apart from each other, the gap between each RF electrode 12a, 12b, 12a', 12b' and the respective dielectric material 11 has a constant height. Typically, the thickness of the head portion 13a and thus the height of the gap is 1 to 2 mm, preferably 1.5 mm. In the embodiment of the Fig. 5 to 10 and how best in Fig. 10, the head portion 13a is disc-shaped.

[0045] In the embodiment of the Fig. 5 to 10 and how best in Fig. 10, the protruding portion 13b is cylindrical and has a length greater than the thickness of the dielectric material 11. Accordingly, when the RF electrodes 12a, 12b, 12a', 12b' and the dielectric material 11 are mechanically connected to each other by the pin separators 13, the ends of the protruding portions 13b distal from the head portion 13a extend beyond the outer planar surface of the dielectric material 11.

[0046] Each protruding portion 13b of each pin separator 13 is electrically connected to an RF power supply to supply an RF voltage to the respective RF electrode 12a, 12b, 12a', 12b'. This connection can be made through connecting elements configured to establish an electrical connection to the RF power supply. Each connecting element can have an opening / recess configured to receive the respective protruding portion 13b. By directly connecting the pin separator 13 to the RF power supply instead of using conductive traces on the dielectric material 11, dielectric losses and heating of the dielectric material 11 can be reduced.

[0047] The connecting elements configured to establish an electrical connection between the protruding portion 13b and the RF power supply can be, for example, wires. The wires can have spring-loaded contacts at their ends to ensure reliable electrical contact. For example, the wires can have spring-loaded gold-plated tubes soldered or crimped to their ends. The inner diameter of the tubes is slightly larger than the outer diameter of the wire ends. A small circular spring is provided in a groove in each tube to ensure reliable cold-welded electrical contact with the wire end.

[0048] Optionally, the ends of the projecting portions 13b, which are located distally from the respective head portions 13a, can also be soldered to the outer larger surface of the dielectric material so that a force on the connecting elements does not cause bending of the RF electrodes 12a, 12b, 12a', 12b'.

[0049] In each electrode arrangement 10, 10', at least one DC voltage electrode 14 is provided on the largest part of the inner larger surface of the dielectric material 11. In the Fig. In the embodiment shown in Figures 5 to 10, a DC electrode 14 segmented by grooves formed in the transverse direction is provided on each dielectric material 11. The grooves are much narrower than the segments defined between the grooves. The thickness of each groove is preferably less than 0.5 mm. The DC electrodes 14 extend from the first end 100a to the second end 100b of the electrode assembly 100 and from the first minor sidewall 101 to the second minor sidewall 102 of the electrode assembly 100. In fact, each DC electrode 14 is provided on the entirety of the inner major surface of the dielectric material 11 extending between the first and second minor sidewalls 101, 102, except for the exposed regions (i.e., the regions of the inner major surface of the dielectric material 11 without a DC electrode 14 provided thereon).

[0050] The exposed areas prevent electrical contact between the RF electrodes 12a, 12b, 12a', 12b' and the DC electrodes 14. As best described in the Fig. 7 to 9, each exposed region includes a contact region 11b, which is the region of the inner major surface of the dielectric material 11 that is in direct contact with the pin separator 13 when the RF electrodes 12a, 12b, 12a', 12b' are connected to the dielectric material 11 (i.e., the region where the head portion 13a of the pin separator 13 contacts the inner major surface of the dielectric material 11). Each exposed region preferably also includes a groove 11c surrounding the contact region 11b. The groove 11c formed around each pin separator 13 increases the creepage distance and avoids electrical breakdown. In the Fig. 5 to 10, as best shown in the Fig. 8 and Fig. As shown in Figure 9, the head portion 13a of the pin separator 13 has the shape of a disc that contacts the inner larger surface of the dielectric material 11 when the RF electrode 12a, 12b, 12a', 12b' is connected to the dielectric material 11. Accordingly, the contact area 11b has a circular shape with approximately the same diameter as the head portion 13a and surrounds the through-hole 11a. The groove 11c surrounding the contact area 11b is formed in the inner larger surface of the dielectric material 11. The groove 11c is annular and has a larger diameter than the head portion 13a.

[0051] Accordingly, the DC electrodes 14 extend over the entire inner larger surface of the dielectric material 11, which extends between the first and second smaller sidewalls 101, 102, except for the contact area 11b and the groove 11c. In fact, the DC electrodes 14 are arranged directly between the outer planar surface of the RF electrode 12a, 12b, 12a', 12b' and the inner larger surface of the dielectric material 11 (except for the exposed areas where the pin separators 13 are located). In fact, the DC electrode 14 of the first electrode arrangement 10 extends directly below the RF electrodes 12a, 12b of the first electrode arrangement 10. The DC electrode 14 of the second electrode arrangement 10' extends directly above the RF electrodes 12a', 12b' of the second electrode arrangement 10'.

[0052] As discussed above, the pin separators 13 are configured to define a gap between the RF electrodes 12a, 12b, 12a', 12b' and the dielectric material 11. The gap is provided in the direction orthogonal to the plane of the dielectric material 11. Accordingly, a gap also extends between the outer surface of the RF electrodes 12a, 12b, 12a', 12b' and the DC electrodes 14 formed on the inner, larger surface of the dielectric material 11. The gap is typically defined by the height of the head portion 13a of the pin separators 13 and is reduced by the thickness of the DC electrodes 14 arranged on the inner surface of the dielectric material 11.

[0053] Preferably, in the electrode arrangement according to the invention, the RF electrodes 12a, 12b, 12a', 12b' protrude above the pin separator 13. In a particularly preferred embodiment, a line of sight exists in the direction orthogonal to the plane of the dielectric material 11 between the region of the RF electrodes 12a, 12b, 12a', 12b', which protrudes above the pin separator 13 and the DC voltage electrode 14. Manufacturing and assembly

[0054] How best in Fig. As shown in Figure 10, which is a schematic diagram of a partially exploded view of the electrode assembly 100, the first electrode assembly 10 is connected to the second electrode assembly 10' at their major edges by fasteners 103. The fasteners may be, for example, nuts and bolts. The nuts may extend through the smaller sidewalls 101, 102 provided along the major edges of the electrode assembly 100.

[0055] The through-holes 11a are formed through the thickness of the dielectric material 11 using a standard manufacturing process for printed circuit boards. The through-holes 11a are provided at spaced positions corresponding to the locations of the pin separators 13 on the RF electrodes 12a, 12b, 12a', 12b'. Preferably, the through-holes 11a are equally spaced along the length of the dielectric material 11.

[0056] The DC electrodes 14 are etched onto the surface of the dielectric material 11, except for the exposed areas, as discussed above. The voltage can be applied to the DC electrodes 14 via supply lines on the PCB formed by the dielectric material 11 and a connector 20, for example, a Molex connector.

[0057] The annular groove 11c of each exposed area is formed in the dielectric material 11 by laser or mechanical cutting. The DC electrodes 14 are segmented in the transverse direction, as discussed above, by grooves formed in the dielectric material 11 by etching.

[0058] A specific DC voltage is applied to each segment of the DC electrodes 14 to control the movement of the ions through the electrode assembly, particularly in the longitudinal direction of the electrode assembly.

[0059] The head portions 13a of the plurality of pin separators 13 are welded to each RF electrode 12a, 12b, 12a', 12b', wherein the RF electrode 12a, 12b, 12a', 12b' has a first length. The pin separators 13 are positioned along the length of the RF electrodes 12a, 12b, 12a', 12b' such that they correspond to the positions of the through-holes in the dielectric material 11. Preferably, the pin separators 13 are equally spaced along the length of the RF electrodes 12a, 12b, 12a', 12b'.

[0060] Each RF electrode 12a, 12b, 12a', 12b' having a first length is connected to the respective dielectric material 11 by the plurality of pin separators 13. As discussed above, to mechanically connect each RF electrode 12a, 12b, 12a', 12b' to the respective dielectric material 11, the protruding portion 13b of each pin separator 13 is inserted into and held in the corresponding through-hole 11a extending through the thickness of the dielectric material 11. This is best described in the Fig. 6 and Fig. 10. Each protruding portion 13b is then soldered to the outer major surface of the dielectric material 11. Typically, each protruding portion 13b is soldered to a conductive contact point provided on the outer major surface of the dielectric material 11. This soldering reduces and preferably avoids bending of the RF electrodes 12a, 12b, 12a', 12b', particularly in the direction orthogonal to the plane of the dielectric material 11. The first length of the RF electrode 12a, 12b, 12a', 12b' is greater than the length of the dielectric material 11 (from the first end 100a to the second end 100b of the electrode assembly 100). Therefore, after bonding, the RF electrodes 12a, 12b, 12a', 12b' extend beyond the dielectric material 11 (in the longitudinal direction).Preferably, the first electrode arrangement 10 is also mechanically connected to the second electrode arrangement 10', while the RF electrodes 12a, 12b, 12a', 12b' have the first length which is greater than the length of the dielectric material 11.

[0061] Once all RF electrodes 12a, 12b, 12a', 12b' are mechanically connected to the respective dielectric material 11 using the plurality of pin separators 13, and preferably once the first electrode assembly 10 is connected to the second electrode assembly 10', the RF electrodes 12a, 12b, 12a', 12b' are trimmed to remove excess material. The RF electrodes 12a, 12b, 12a', 12b' can be reshaped by the cutting process. In particular, the RF electrodes 12a, 12b, 12a', 12b' are trimmed to reduce the length of the RF electrodes 12a, 12b, 12a', 12b' from the first length to the second length. The second length of the RF electrodes 12a, 12b, 12a', 12b' is equal to the length of the dielectric material 11. All four RF electrodes 12a, 12b, 12a', 12b' are cut simultaneously from the first length to the second length.The RF electrodes 12a, 12b, 12a', 12b' are cut using a wire EDM process with a wire extending orthogonally to the longitudinal direction of the RF electrodes 12a, 12b, 12a', 12b'. Optionally, the wire EDM process can be used with a wire extending parallel to the longitudinal direction to precisely reduce the width and / or reshape the RF electrodes 12a, 12b, 12a', 12b'. By simultaneously cutting the RF electrodes 12a, 12b, 12a', 12b' once they are bonded to the dielectric material 11, manufacturing and assembly precision is increased. In fact, this process allows the manufacture and assembly of the RF electrodes 12a, 12b, 12a', 12b' with a relative error of less than 10 µm relative to each other, while the tolerances in the manufacture of LPn are typically in the range of 50-200 µm.Therefore, this process of manufacturing and assembling the RF electrodes 12a, 12b, 12a', 12b' results in higher mechanical precision and reduces variability between systems employing the electrode assemblies 10, 10'. Furthermore, the precision of ion transmission and ion focusing is improved by using the RF electrodes 12a, 12b, 12a', 12b'.

[0062] The improved cutting process for the RF electrodes 12a, 12b, 12a', 12b' is possible in particular due to the novel arrangement, in which the RF electrodes are bonded to the dielectric material. They are positioned only by the pin separators 13, and therefore the design of the RF electrodes 12a, 12b, 12a', 12b' can be precisely formed, especially if they protrude beyond the pin separators 13.

[0063] At least one of the pin separators 13 connected to each RF electrode 12a, 12b, 12a', 12b' is then electrically connected to an RF power supply, so that an RF voltage is applied through the pin separators 13 to the RF electrodes 12a, 12b, 12a', 12b'. Preferably, the distal end of the protruding portion 13b of each pin separator 13 is electrically connected to the RF power supply. This can be achieved by soldering the distal ends of the pin separators 13 to wires configured to supply the RF voltage. Operational

[0064] In operation, an RF voltage is applied from an RF power supply to the RF electrodes 12a, 12b, 12a', 12b'. The RF electrodes 12a, 12b, 12a', 12b' form a multipole (in this case, a quadrupole). In fact, the RF voltage is applied such that adjacent RF electrodes 12a, 12b, 12a', 12b' of the multipole have opposite phases. Therefore, electrodes 12a and 12b' are connected as one set so that they have the same phase, while electrodes 12b and 12a' are connected as another set so that they have the same phase but opposite to that of 12a and 12b'. Accordingly, the RF electrodes 12a, 12b, 12a', 12b' generate a pseudopotential function that defines an ion flow path in the form of an ion optical axis extending parallel to the longitudinal direction of the electrode assembly 100.

[0065] In operation, a DC voltage can be applied to the DC electrodes 14. The DC voltage is applied to the DC electrode segments such that the DC electrode segments provide a DC potential that preferably increases monotonically from the first end 100a to the second end 100b of the electrode assembly. Preferably, the increasing DC potential is provided by using a resistive divider positioned on an outer surface of the dielectric material 11, which is connected to each DC electrode segment by a connecting element 22 and has equal resistances. Preferably, a linear voltage distribution is defined, although this is more complicated, and time-dependent distributions can also be employed to enable ion manipulation within the ion electrode assembly.For example, the ions can be moved either to the first end 100a or to the second end 100b of the electrode assembly 100 in synchronization with further stages of mass analysis. Ion mobility separation can also be enabled in a gas-filled guide. This can be achieved if the drift velocity is provided by a DC voltage gradient on the electrode assembly. Preferably, the RF electrodes 12a, 12b, 12a', 12b' can be divided into multiple segments, each of which is applied its own DC voltage. The DC voltage can be provided, for example, by the same resistive divider used to power the segments of the DC electrode.By dividing the RF electrodes 12a, 12b, 12a', 12b' into multiple segments, each of which is applied with its own DC voltage, in addition to the segments of the DC electrode, the generation of stronger axial gradients in the electrode assembly is enabled.

[0066] The Fig. 10a and Fig. 10b show cross sections of the electrode assembly of the Fig. 5 to 10 along lines AA' and BB', as in Fig. 10. The Fig. 10a and Fig. 10b also shows as dashed lines the equipotential 27 of 75% of the RF voltage applied to the RF electrodes 12a and 12b and the equipotential 28 of 25% of the RF voltage applied to the RF electrodes 12a and 12b.

[0067] The gap between the RF electrode 12a, 12b, 12a', 12b' and the dielectric material 11 allows the DC electrode 14 provided directly therebetween to shield the dielectric material 11 against the RF field generated by the RF electrode 12a, 12b, 12a', 12b'. This shielding prevents the RF field from penetrating the dielectric material 11, as indicated by the equipotential lines 27, 28 in Fig. 10b, thus preventing the generation of heat in the dielectric material 11 due to dielectric loss. The only penetration of the RF field into the dielectric material 11 occurs at the exposed areas (the exposed areas include the contact area 11b between each pin separator 13 and the dielectric material 11, the groove 11c surrounding the contact area 11b (as shown in Fig. 10a for electrode 12b), and the grooves between the segments of each DC electrode 14). In the present invention, the exposed areas have been minimized by providing a plurality of separators at spaced positions along the length of the RF electrode 12a, 12b, 12a', 12b'.

[0068] This differs significantly from the known electrode assembly 1, which is used in the Fig. 1 and Fig. 1a is shown. Fig. Figure 1a also shows, as dashed lines, the equipotential 24 of 75% of the RF voltage applied to the RF electrodes 3 and the equipotential 26 of 25% of the RF voltage applied to the RF electrodes 3. In this known electrode assembly 1, the RF field penetrates the dielectric material 4 below / above the RF electrodes along the entire length of the RF electrodes 3. The penetration of the RF field therefore occurs over a larger area of ​​the dielectric material 4 of the known electrode assembly 1 compared to the penetration of the RF field in the electrode assembly of the claimed invention. The penetration of the RF field over a larger area in the known electrode assembly 1 causes greater heating of the dielectric material 4.

[0069] The electrode arrangements 10, 10' of the present invention can, as shown in the Fig. 5 to 10, can be used in reaction cells, particularly in collision cells or fragmentation cells that employ processes such as collision-induced dissociation (CID), electron capture dissociation (ECD), electron transfer dissociation (ETD), photodissociation, and so on. In ETD, the RF electrodes 12a, 12b, 12a', and 12b' can be segmented into elongated segments by grooves formed in the longitudinal direction. The elongated segments can have independently controlled DC offsets and applied RF voltages, as is known in the art, e.g., according to US Pat. No. 7,145,139.

[0070] The electrode arrangements 10, 10' of the present invention can, as shown in the Fig. 5 to 10, in an ion guide, an ion filter such as a quadrupole mass filter, an ion mobility spectrometer, an ion trap such as a linear ion trap, an ion storage device, or an ion analyzer such as a mass analyzer. Indeed, the electrode assemblies 10, 10' can be used in any device that creates an RF multipole using planar RF electrodes bonded to dielectric materials. The use of RF electrodes in ion traps, ion guides, ion filters, reaction cells, ion storage devices, and ion analyzers is well known to those skilled in the art.

[0071] In a preferred embodiment, the electrode assembly 100 is provided with the electrode arrangements 10, 10' as shown in the Fig. 5 to 10, is used in a collision cell, such as an HCD (Higher Energy Collision Dissociation) cell. A collision cell is typically disposed in the ion path of a mass spectrometer, such as a mass spectrometer comprising a quadrupole and an Orbitrap mass analyzer. When the electrode assembly 100 is disposed in a collision cell, the electrode assembly 100 additionally includes third and fourth smaller sidewalls at the first and second ends 100a, 100b of the electrode assembly 100. An opening is provided in the third smaller sidewall at the first end 100a of the electrode assembly 100, and optionally, an opening is also provided in the fourth smaller sidewall at the second end 100b of the electrode assembly 100.In operation, ions, referred to as precursor ions, enter the electrode assembly 100 through the opening at the first end 100a into the space between the first and second electrode assemblies 10, 10'. The space may be filled with nitrogen, argon, or another suitable collision gas for collision cooling and / or fragmentation of ions. If fragmentation is desired, the precursor ions are accelerated into the collision cell at a desired collision energy by adjusting the DC voltage applied to the DC electrodes to adjust the DC offset between the collision cell and components upstream of the collision cell. Alternatively, if the precursor ions are to remain intact, the DC offsets are adjusted to maintain the energies of the entering ions at a level where no or minimal fragmentation occurs. The precursor ions / . Fragments can then exit the electrode assembly 100 through the opening at the second end 100b. Alternatively, the collision cell with the electrode assembly 100 can have a "dead-end" configuration. In such a configuration, there is no opening at the second end 100b, and the precursor / fragment ions exit the electrode assembly 100 through the opening at the first end 100a.

[0072] When the electrode assembly 100 with the first and second electrode arrangements 10, 10', as shown in the Fig. 5 to 10, is instead used in an ion guide, such as a curved flatapole, ions enter the electrode assembly 100 via the first end 100a and are confined within the electrode assembly 100 for movement along the longitudinal axis. The DC electrode 14 can be configured to generate a DC electric field that moves the ions through the electrode assembly 100 along the longitudinal direction. The ions then exit the ion guide via the second end 100b.

[0073] The Fig. 15 and Fig. 16 show a second embodiment of the first electrode assembly 10 of the present invention. Although only the first electrode assembly 10 is shown, it is understood that the second electrode assembly 10' may be configured in a similar manner. The difference between the Fig. 15 and Fig. 16 and the second embodiment shown in the Fig. 5 to 10 is that the second embodiment comprises separators 13' provided with a receptacle and projecting separators 13" instead of pin separators 13. Separators 13' provided with a receptacle are shown in Fig. 16 is shown in more detail.

[0074] The difference between the separators 13' provided with a receptacle and the pin separators 13 is that in the separators 13' provided with a receptacle, each head portion 13a comprises a receptacle 13d for receiving a protruding portion 12c extending from the main body of the RF electrodes 12a, 12b, 12a', 12b'. The description of the other components of the Fig. 5 to 10 also applies to the equivalent components of the Fig. 15 and Fig. 16, which are provided with the same reference numerals. The description of the projecting portion 13b of the pin separator 13 with reference to the Fig. 5 to 10 also applies to the projecting area 13b of the separator 13' provided with a receptacle of the Fig. 15 and Fig. 16.

[0075] The receptacle-equipped separators 13' are mechanically connected to the RF electrodes 12a, 12b, 12a', 12b'. The RF electrodes 12a, 12b, 12a', 12b' each have a main body that is elongated and extends in the longitudinal direction of the electrode assembly 10. The main body of the RF electrodes 12a, 12b, 12a', 12b' includes the larger and smaller surfaces, as described above. As also described above, the larger surfaces of the RF electrodes 12a, 12b, 12a', 12b' are arranged parallel to the plane of the dielectric surface 11. The smaller surfaces of the RF electrodes 12a, 12b, 12a', 12b' are arranged orthogonal to the planar dielectric surface 11. In the second embodiment, the RF electrodes 12a, 12b, 12a', 12b' comprise the main body and a plurality of protruding portions 12c extending from the main body. Each protruding portion 12c is received in the respective receptacle 13d.Each projecting portion 12c of each RF electrode 12a, 12b, 12a', 12b' is inserted into and held in the corresponding receptacle 13d of the receptacle-provided separator 13'.

[0076] Each receptacle 13d includes an opening 13e for receiving the protruding portion 12c. The opening 13e may have a shape complementary to the corresponding protruding portion 12c. The opening 13e may be a through-hole or, instead, a recess extending only partially through the receptacle 13d. The receptacle 13d and its opening 13e have a longitudinal axis extending in the direction orthogonal to the plane of the dielectric material 11. The opening 13e extends in the direction orthogonal to the plane of the RF electrodes 12a, 12b, 12a', 12b'. The diameter of the opening 13e formed in the receptacle 13d may be equal to or larger than the diameter of the protruding portion 12c of the RF electrode 12a, 12b, 12a', 12b'. Preferably, the receptacle comprises a circular spring (not shown) which exerts a retaining force on the protruding portion 12c to hold the protruding portion 12c in the opening 13e of the receptacle 13d.The receptacle 13d may include a mechanical support and an alignment for the RF electrodes 12a, 12b, 12a', 12b'.

[0077] As discussed above with reference to the pin separators 13, the receptacle-equipped separators 13' are configured to define a gap between the RF electrodes 12a, 12b, 12a', 12b' and the dielectric material 11. The gap is provided in the direction orthogonal to the plane of the dielectric material 11. Accordingly, a gap also extends between the outer (larger) surface of the RF electrodes 12a, 12b, 12a', 12b' and the DC electrodes 14 formed on the inner (larger) surface of the dielectric material 11. This was discussed above with reference to the pin separators 13 in the Fig. 5 to 10 and also applies to the separators 13' provided with a receptacle of the embodiment shown in the Fig. 15 and Fig. 16 shown embodiment.

[0078] Each protruding portion 12c preferably extends only partially into the opening 13e, so that a gap is formed between the bottom wall 13f of the receptacle 13d and the end of the protruding portion 12c distal from the main body of the respective RF electrode 12a, 12b, 12a', 12b'. This gap is provided along the longitudinal axis of the receptacle (i.e., orthogonal to the plane of the RF electrodes 12a, 12b, 12a', 12b'). By inserting the protruding portion 12c into the opening 13e in the receptacle 13d, vibrations or bending of the electrodes are avoided.

[0079] The protruding portions 12c are preferably formed integrally with the RF electrodes 12a, 12b, 12a', 12b' and constitute a part thereof. Each protruding portion 12c extends from the smaller surface of the main body of the respective RF electrode 12a, 12b, 12a', 12b'. Each protruding portion 12c connects the smaller surface of the RF electrode 12a, 12b, 12a', 12b' to the separator 13. Each protruding portion 12c has a first portion in a first plane and a second portion in a second plane. The first plane is the plane of the main body of the RF electrodes 12a, 12b, 12a', 12b', i.e., the first section extends in the plane of the RF electrodes 12a, 12b, 12a', 12b'. The first section extends in a direction away from the main body of the respective RF electrode 12a, 12b, 12a', 12b' (i.e., in a direction with a non-zero angle to the longitudinal axis of the RF electrode 12a, 12b, 12a', 12b').Most preferably, the first portion extends in the plane of the RF electrode 12a, 12b, 12a', 12b' in a direction perpendicular to the longitudinal axis of the RF electrode 12a, 12b, 12a', 12b'. At least a portion of the second portion is received in the receptacle 13d. The second portion extends at an angle to the plane of the RF electrode 12a, 12b, 12a', 12b' (i.e., the second portion extends out of the plane of the RF electrode 12a, 12b, 12a', 12b') such that it enters the receptacle 13d. The second plane is arranged at an angle relative to the first plane. In a preferred embodiment, the second plane is arranged orthogonal to the first plane. Preferably, each projecting portion has a curved section connecting the first and second sections, and thus the projecting portion transitions from the first plane to the second plane.However, in an alternative arrangement, the projecting portion 12c may not have a curved portion, and instead the first portion may be directly connected to the second portion such that the first portion intersects the second portion at a non-zero angle.

[0080] The description of the projecting portions 13b of the pin separators 13, as described above with reference to the embodiment in the Fig. 5 to 10, also applies to the projecting areas 13b for the separators 13' provided with a receptacle in the Fig. 15 and Fig. 16 shown second embodiment. In fact, in the Fig. 15 and Fig. 16 each projecting portion 13b extends from the head portion 13a in a direction orthogonal to the plane of the RF electrode 12a, 12b, 12a', 12b' and orthogonal to the plane of the dielectric material 11. Each projecting portion 13b is received and held in the corresponding receiving portion 11a of the dielectric material 11, as discussed in more detail above.

[0081] Each protruding portion 12c of the RF electrode 12a, 12b, 12a', 12b' is formed integrally with the RF electrode 12a, 12b, 12a', 12b' and is thus described as part of the RF electrode 12a, 12b, 12a', 12b'. Preferably, the RF electrodes 12 are made from flat plates, e.g., by laser cutting or pressing, and then the protruding portion 12c is bent downward from the flat plate on a special assembly device. In this case, the cross-section of the protruding portion 12c is typically square. Alternatively, and less preferably, the protruding portion 12c may be attached to the RF electrode 12a, 12b, 12a', 12b' by laser or electron beam welding instead of being formed integrally with the RF electrode 12a, 12b, 12a', 12b'.

[0082] The receptacle 13d is shown with a square cross-section, and its opening 13e has a circular cross-section. Of course, it is understood that other shapes may also be used. For example, the receptacle 13d may have a cylindrical cross-section, and its opening 13e may have a square cross-section. Of course, the cross-section of the protruding portion 12c may also have a different shape than that shown in the Fig. 15 and Fig. 16 have the square shape shown.

[0083] As discussed above, the receptacled separators 13' are offset from the RF electrodes 12a, 12b, 12a', 12b' such that no overlap occurs between the larger surfaces of the RF electrodes 12a, 12b, 12a', 12b' and the receptacled separators 13'. Instead, the receptacled separators 13' may be offset such that an overlap occurs between the larger surfaces of the RF electrodes 12a, 12b, 12a', 12b' and the receptacled separators 13'.

[0084] The separators 13' provided with a receptacle are shown arranged on the same side of the respective RF electrode 12a, 12b, 12a', 12b'.

[0085] Instead, the separators 13' provided with a receptacle can also be arranged on each side of the RF electrodes 12a, 12b, 12a', 12b'.

[0086] The protruding portions 12c are illustrated as having first and second sections and are preferably fabricated from flat material. Alternatively, each protruding portion 12c may extend from the RF electrode 12a, 12b, 12a', 12b' in the plane of the RF electrode at an angle to the longitudinal axis of the RF electrode. The protruding portions 12c may be linear. In one arrangement, each receptacle 13d may extend in the plane of the RF electrode 12a, 12b, 12a', 12b' at an angle to the longitudinal axis of the RF electrode, such that the protruding portion 12c, which is linear, is received in the receptacle 13d. The protruding portion 13b may have a first part extending in the plane of the RF electrode and connected to the receptacle 13d, and a second part extending at an angle to the plane of the RF electrode and received in the receptacle portion 11a of the dielectric material 11.The first and second parts may be connected by a curved part. The second part may extend in the direction out of the plane of the RF electrode 12a, 12b, 12a', 12b', preferably orthogonal to the plane of the RF electrode 12a, 12b, 12a', 12b'. Alternatively, each projecting portion 12c may extend from the larger surface of the RF electrode 12a, 12b, 12a', 12b' in the direction out of the plane of the RF electrodes 12a, 12b, 12a', 12b' and into the receptacle 13d. In this arrangement, the receptacle separators 13' may be positioned in line with or close to the central longitudinal axis of the RF electrodes 12a, 12b, 12a', 12b'.

[0087] In this second embodiment, a plurality of projecting separators 13" are also optionally provided in addition to the receptacle-provided separators 13'. The plurality of projecting separators 13" are spaced apart from each other. The plurality of projecting separators 13" may be positioned at a plurality of points along the RF electrode 12a, 12b, 12a', 12b', preferably at two or three points, as shown in Fig. 15 where they are positioned at two points along the RF electrode 12a, 12b, 12a', 12b'.

[0088] Similar to the pin separators 13 and the receptacle-type separators 13', the projecting separators 13" may define the gap between the RF electrode(s) 12a, 12b, 12a', 12b' and the dielectric material 11. Each projecting separator 13" connects the larger planar surface of the RF electrode 12a, 12b, 12a', 12b' to the dielectric material 11. The projecting separators 13" differ from the pin separators 13 of the Fig. 5 to 10 in that each protruding separator 13" does not have a head portion 13a with a larger diameter than a protruding region 13b. Instead, each protruding separator 13" is formed from the protruding region 13b extending between a first end 13g and a second end 13h along a longitudinal axis of the separator 13", i.e., in a direction orthogonal to the larger planar surface of the dielectric material 11 and the larger planar surface of the RF electrodes 12a, 12b, 12a', 12b'. The first end 13g of the protruding region 13b is received in the corresponding receiving region 11a in the dielectric material 11. The second end 13h of the protruding region 13b is received in an opening 12d in the RF electrode 12a, 12b, 12a', 12b' recorded.Accordingly, the protruding separator 13" extends between the inner surface of the dielectric material 11 and the RF electrode 12a, 12b, 12a', 12b' in the direction orthogonal to the plane of the dielectric material 11. The protruding portion 13b is cylindrical and has a circular cross-section. However, other cross-sectional shapes, such as square ones, may also be used.

[0089] Each receiving region 11a in the dielectric material 11 and each opening 12d in the RF electrode 12a, 12b, 12a', 12b' may have a shape complementary to the first end 13g and the second end 13h of the protruding region 13b. Each receiving region 11a and / or each opening 12d may be a through-hole or, instead, a recess. Preferably, the receiving region 11a is a through-hole, and the first end 13g of the protruding region 13b extends through the receiving region 11a, such that the first end 13g extends beyond the outer surface of the dielectric material 11. Preferably, the opening 12d in the RF electrode 12a, 12b, 12a', 12b' is a through-hole, and the second end 13h of the protruding portion 13b extends through the opening 12d in the RF electrode, such that the second end 13h extends beyond the inner surface of the RF electrode 12a, 12b, 12a', 12b'.

[0090] Each receiving area 11a in the dielectric material and each opening 12d in the RF electrode 12a, 12b, 12a', 12b' can be machined, punched, or laser cut. The first end 13g and the second end 13h of the projecting separators 13" may be attached to the dielectric material 11 and to the RF electrodes 12a, 12b, 12a', 12b', respectively, for example, by nuts and bolts, circular clamps, soldering, gluing, or welding. As discussed above, each projecting portion 13b may be soldered to the outer major surface of the dielectric material 11. Typically, each projecting portion 13b is soldered to a conductive contact point provided on the outer major surface of the dielectric material 11. Each projecting portion 13b of the projecting separators 13" may also be soldered to the inner major surface of the RF electrode 12a, 12b, 12a', 12b'.

[0091] As in Fig. 15, the projecting separators 13" are preferably mechanically connected to one or more end portions 12e of the RF electrodes. The openings 12d may, as discussed above, be formed in the one or more end portions 12e for receiving the second end 13h of each projecting portion 13b. Each end portion 12e is planar and has a major planar area parallel to and opposite the dielectric material 11. As discussed above, the main body of the RF electrodes 12a, 12b, 12a', 12b' is elongated and extends in the longitudinal direction of the electrode assembly. Preferably, each end portion 12e extends in the plane of and laterally to the main body of the RF electrodes 12a, 12b, 12a', 12b'. More preferably, each end portion 12e extends in the plane of the main body of the RF electrodes 12a, 12b, 12a', 12b' and perpendicular to the longitudinal axis of the main body of the RF electrodes 12a, 12b, 12a', 12b'.Therefore, the projecting separators 13" are offset and do not overlap the main body of the RF electrodes 12a, 12b, 12a', 12b'. In other words, the projecting separators 13" are offset and do not overlap the larger surfaces of the RF electrodes 12a, 12b, 12a', 12b' that extend along the longitudinal direction of the electrode assembly 10.

[0092] In the Fig. In the embodiment shown in Figure 15, a first protruding separator 13" is mechanically connected to a first end portion 12e, and a second protruding separator 13" is mechanically connected to a second end portion 12e of the RF electrode 12a, 12b, 12a', 12b'. Preferably, the first end portion 12e is spaced from the second end portion 12e along the longitudinal direction of the electrode assembly 10.

[0093] As discussed above with respect to the protruding portion 13b of the pin separators, the first end 13g of the protruding portion 13b of the protruding separators 13" may be electrically connected to an RF power supply to supply an RF voltage to the respective RF electrode 12a, 12b, 12a', 12b'. This connection may be provided by connectors configured to provide electrical connection to the RF power supply. The connectors have been discussed above.

[0094] As also discussed above, the inclusion of the projecting separators 13" in addition to the receptacled separators 13' is optional. Similarly, the inclusion of the receptacled separators 13' in addition to the projecting separators 13" is optional. In Fig. 15, both the receptacled separators 13' and the protruding separators 13" are present. By providing both the receptacled separators 13' and the protruding separators 13", the size of the gap between each RF electrode 12a, 12b, 12a', 12b' and the inner surface of the dielectric material 11 can be more precisely defined and maintained. If both receptacled separators 13' and protruding separators 13" are present, then the protruding separators 13" can define the gap between the RF electrode 12a, 12b, 12a', 12b' based on the distance between the first end 13g and the second end 13h (i.e., the height of the separator 13").The retaining separators 13' can ensure the relative alignment of the RF electrodes 12a, 12b, 12a', 12b' and the dielectric material 11 and prevent vibrations or bending of the RF electrodes 12a, 12b, 12a', 12b', as discussed above. The thickness of a bottom wall 13f of the retaining 13d of each retaining separator 13' can be selected to allow adjustment of the gap. Movement of the electrodes 12a, 12b, 12a', 12b' due to high forces, e.g., during transport, can be limited by supporting the protruding portion 12c and the bottom wall 13f of the retaining.

[0095] Although in the Fig. 15 to 16, in the second embodiment, at least one DC electrode 14 is provided on most of the inner larger surface of the dielectric material, similar to Fig. 5 to 10. The description of the DC electrode(s) 14 above with respect to the Fig. 5 to 10 also applies to the Fig. 15 and Fig. 16.

[0096] In the embodiment shown in the Fig. 15 and Fig. 16, the entire planar surface of the dielectric material 11 can be covered with the DC electrodes 14, in contrast to the larger surface of the RF electrode, which extends parallel to the longitudinal direction of the electrode assembly. Typically, a coverage of up to 90-95% of the surface of the dielectric material 11 can be achieved. Fig. 15 and Fig. In the embodiment shown in Figure 16, a line of sight in the direction orthogonal to the plane of the dielectric material 11 exists between the entire larger surface of the RF electrode, which extends parallel to the longitudinal axis of the electrode assembly, and the DC electrode(s) 14 on the dielectric material 11. In other words, there is no overlap between the larger surfaces of the RF electrodes 12a, 12b, 12a', 12b', which extend parallel to the longitudinal axis of the electrode assembly, and the receptacled or projecting separators 13', 13". The entire larger (planar) surface of the electrodes 12a, 12b, 12a', 12b', which extend parallel to the longitudinal axis of the electrode assembly, protrudes beyond the receptacled separators 13'.Therefore, more than 90% of the surface area of ​​the larger (planar) surface of the RF electrodes 12a, 12b, 12a', 12b', which extend parallel to the longitudinal axis of the electrode, can be shielded from the dielectric material by the DC electrode(s) 14.

[0097] As discussed above with respect to pin separators 13, the receptacled separators 13' and the protruding separators 13" may also be electrically conductive and preferably metallic. The receptacled separators 13' and the protruding separators 13" are spaced along a surface of the dielectric material 11 and are preferably equidistant. The receptacled separators 13' and the protruding separators 13" may typically be made of copper or the same material as the RF electrodes 12a, 12b, 12a', 12b'. The receptacled separators 13' and the protruding separators 13" may also be non-permanently attached to the surface of the RF electrode 12a, 12b, 12a', 12b'. For example, for the separator 13' provided with a receptacle, the projecting portion of the RF electrode 12a, 12b, 12a', 12b' may be removably received in the receptacle 13d.For the projecting separator 13", the projecting portion 13b may be removably received in the opening 12d.

[0098] The description of the use of the electrode assembly 1, comprising the electrode arrangement 10 of the Fig. 5 to 10, also applies to the electrode assembly with the electrode arrangement of the Fig. 15 and Fig. 16 shown second embodiment.

[0099] The manufacturing and assembly of the electrode assembly 1 including mechanically connecting the RF electrode to the dielectric material using the plurality of separators spaced apart from each other so that a gap is defined between the RF electrode and the dielectric material, and then cutting the RF electrode while the RF electrode is connected to the dielectric material so as to reshape the RF electrode, applies to both the Fig. 5 to 10 as well as the Fig. 15 and Fig. 16 embodiments shown. Experimental results

[0100] The results of an experiment, referred to herein as Experiment 2, in which the same isolated charge state (+11) of multiply charged ubiquitin ions as in Experiment 1 was used in an HCD (higher energy collision dissociation) cell with the electrode assembly 100 of the type described in the Fig. 5 to 10 shown in the claimed invention are shown in the Fig. 11 to 14. As in Experiment 1, the isolated and captured ubiquitin ions were then transferred from the HCD cell to a C-trap and injected from the C-trap into an Orbitrap mass analyzer for mass analysis. The HCD cell was positioned adjacent to the C-trap so that the C-trap was upstream of the HCD cell. The charge state (+11) of multiply charged ubiquitin ions was stored in the HCD cell with a storage time of 500 milliseconds. At time 0:00 (i.e., at the beginning of the experiment), a high RF voltage was applied to the RF electrodes 12a, 12b, 12a', 12b' of the HCD cell (approximately 1250 Vpp), and approximately 3000 Vpp was applied to the RF electrodes of the adjacent C-trap. The application of the maximum RF voltage to the RF electrodes 12a, 12b, 12a', 12b' was maintained for a period of 2 hours and 30 minutes.The main difference between Experiment 1 and Experiment 2 is that in Experiment 1, the HCD cell used the electrode assembly 1 of . Fig. 1, and in Experiment 2 the HCD cell used the electrode assembly 100 of the Fig. 5 to 10. Another difference is that in Experiment 2, the maximum RF voltage was applied to the HCD cell for 2 hours and 30 minutes, and in Experiment 1, the maximum RF voltage was applied for only 1 hour and 12 minutes. The remaining experimental conditions were essentially the same. Accordingly, the charge reduction data of the Fig. 11 and Fig. 13 directly with those of Fig. 2. The mass spectra of the Fig. 14(a) and (b) directly with those of the Fig. 3(a) and (b) are comparable.

[0101] Fig. Figure 11 is a graphical representation of the ion current per charge state of the HCD cell versus time for Experiment 2. The ion current per charge state of the HCD cell is the mass flow of ubiquitin ions of a specific charge state when the ions are extracted from the HCD cell after being trapped for over 500 milliseconds. As shown in Fig. As shown in Figure 11, the extracted ion current varies throughout the experiment. This is likely due to the conditions of the ion source. In view of this variation, the graphical representation of Fig. 12 is provided. Fig. Figure 12 is a graph of extracted ion current versus time, where the extracted ion current corresponds to the graph of Fig. 11 was normalized at each time point by the extracted ion current of the ions with the charge state (+11). Accordingly, the influence of the varying total ion intensity on the data was eliminated. As can be seen in Fig. As can be seen in Figure 12, the intensity for the ions with the charge state (+11) is always 100%. The ion with the second highest intensity is the ion with the charge state (+10). The ion with the charge state (+10) has a stable intensity of approximately 10%. Accordingly, the charge reduction is stabilized and remains at approximately only 10%, even when the maximum RF voltage was applied to the HCD cell for the longer period of 2 hours and 30 minutes. This is significantly reduced compared to the charge reduction of over 100% in Experiment 1.

[0102] The data of the Fig. 11 and Fig. 12 were further processed to Fig. 13 to generate the graphical representation shown. Fig. Figure 13 is a plot of charge reduction versus time. As discussed above, charge reduction is defined as the ratio of the sum of the extracted ion current from all peaks except the isolated charge state (+11) to that of the isolated charge state (+11). Fig. Figure 13 shows that the charge reduction begins at approximately 8% on average at the beginning of the experiment and reaches approximately 12% after the first hour. Over the remaining hour and twenty-four minutes, the charge reduction level remains at 12%. Accordingly, the charge reduction is significantly reduced and stabilizes at the reduced level when the experiment is conducted with an HCD cell having the electrode assemblies 10, 10' of the claimed invention.

[0103] Fig. Figure 14(a) is a mass spectrum obtained at the beginning of Experiment 2 (time 0:00). As in Fig. As shown in Figure 14(a), the relative abundance of the isotope with the isolated charge state (+11) at time 0:00 is 100%, and the relative abundance of each of the other isotopes is less than 5%. Fig. Figure 14(b) is a mass spectrum obtained during Experiment 2 at time 2:30 (2 hours and 30 minutes). Accordingly, the mass spectrum of Fig. 14(b) when the maximum RF voltage was applied for 2 hours and 30 minutes. When comparing the Fig. 14(a) and Fig. 14(b) shows that over the duration of the experiment, the relative abundance of the isotope with the isolated charge state (+11) has not changed. In fact, the mass spectra of Fig. 14(a) and of Fig. 14(b) are identical, even though the maximum RF voltage was applied for 2 hours and 30 minutes. Accordingly, it can be seen that no charge reduction of the isolated isotope (+11) occurred during operation of the HCD cell with the electrode assembly 100 comprising the electrode assemblies 10, 10' of the claimed invention, as shown in Fig. 5 to 10 shown.

[0104] In addition to the advantageous electrode assemblies 10, 10' of the claimed invention, a further improvement can be achieved by using Megtron 6 as the dielectric material 11 forming the PCB instead of Panasonic 1755M. In known electrode assemblies, the dielectric material forming the PCB typically comprises Panasonic 1755M. In the claimed invention, the dielectric material 11 is preferably Megtron 6. The use of Megtron 6 results in further reduced dielectric losses. In fact, the loss factor Df for Megtron 6 is 0.0015-0.0020, while the loss factor Df for Panasonic 1755M is 0.014.

[0105] While the Fig. 11 to 14 refer to the use of the claimed electrode assemblies 10, 10' and the assembly 100 in HCD cells, the advantages of the electrode assemblies 10, 10' of the present invention apply equally to other reaction cells, in particular collision cells, ion guides, ion traps, ion filters, ion analyzers or other devices that generate an RF multipole using planar RF electrodes bonded to dielectric materials.

[0106] It is understood that the above-mentioned provisions regarding Fig. 5 to 10 are for illustrative purposes only, and the invention is not limited thereto. Various modifications and alternatives are familiar to those skilled in the art and fall within the scope of the claims.

[0107] Further embodiments of the invention may combine several features of various embodiments described in this specification. For example, various embodiments may use one or a combination of pin separators 13, receptacled separators 13', or protruding separators 13" in an electrode assembly.

[0108] While the HF electrodes 12a, 12b, 12a', 12b' of the Fig. 5 to 10 (and the main bodies of the RF electrodes 12a, 12b, 12a', 12b' of the Fig. 15 and Fig. 16) are straight and elongated, the RF electrodes 12a, 12b, 12a', 12b' may instead be circular or curved, wherein in some embodiments each electrode may lie in the plane of the planar dielectric surface, and in some further embodiments each RF electrode 12a, 12b, 12a', 12b' may lie in the plane perpendicular to the planar dielectric surface. The RF electrodes 12a, 12b, 12a', 12b' may be bent into a curve or other shapes. For example, the RF electrodes 12a, 12b, 12a', 12b' may be implemented as ring-shaped RF electrodes, which may be used to form an ion funnel. In this arrangement, the separators 13, 13', 13" (which may be pin separators 13, receptacle separators 13', or protruding separators 13") may connect the dielectric material 11 to an outer periphery of the annular RF electrodes.For example, the annular RF electrodes may include protruding portions 12c extending radially from the outer periphery of the annular RF electrodes toward the dielectric material 11. The protruding portions 12c may be received in corresponding receptacles 13e of the receptacled separators 13'. The receptacles 13e may be positioned on the larger planar surface of the dielectric material 11.

[0109] The first and second smaller side walls 101, 102 may be bent or curved.

[0110] The size of the space between the first and second electrode assemblies 10, 10' may vary, for example, by changing the distance between the dielectric materials 11, or by varying the thickness of the head portion 13a of each pin separator 13, or by varying the thickness of the bottom wall 13f of each receptacle-equipped separator 13', or by varying the height of each protruding separator 13".

[0111] The DC electrodes 14 are described as being etched onto the surface of the dielectric material 11, but may instead be formed by other methods. For example, the DC electrodes 14 may be formed by stamping, extrusion, laser cutting, or other suitable manufacturing processes.

[0112] The RF electrodes 12a, 12b, 12a', 12b' can be formed by machining, punching, laser cutting, extrusion, etching, etc.

[0113] While the Fig. 5 to 10, 15 and 16 show RF electrodes 12a, 12b, 12a', 12b' forming a quadrupole, can also be higher order multipoles, such as

[0114] Hexapoles, octopoles, dodecapoles can be used following the same methodology.

[0115] While the Fig. 5 to 10 has four pin separators 13, the embodiment shown in the Fig. 15 and Fig. The embodiment shown in Figure 16 comprises four separators 13' provided with a receptacle and two projecting separators 13" for each RF electrode 12a, 12b, 12a', 12b'. The invention can be used with a smaller or larger number of separators 13, 13', 13" (pin separators 13, separators 13' provided with a receptacle, or projecting separators 13") for each RF electrode 12a, 12b, 12a', 12b'. Preferably, the number of separators 13 for each RF electrode 12a, 12b, 12a', 12b' is not greater than eight and can be, for example, two, three, five, six, or eight. Furthermore, the stability of the mounting of the RF electrodes 12a, 12b, 12a', 12b' must be taken into account when determining the number of separators 13 (which may be pin separators 13, receptacle-type separators 13', or projecting separators 13").

[0116] While the separators 13, 13', 13" (pin separators 13, separators 13' provided with a receptacle or projecting separators 13") of the Fig. 5 to 10, 15, and 16 preferably have the same spacing along the length of the RF electrodes 12a, 12b, 12a', 12b', the separators 13 may also not have the same spacing. The separators 13, 13', 13" are preferably positioned such that the RF voltage is applied equally to the RF electrodes 12a, 12b, 12a', and 12b'.

[0117] The separators 13, 13', 13" (pin separators 13, receptacled separators 13', or protruding separators 13") are at least electrically connected to the RF electrodes 12a, 12b, 12a', 12b'. The separators 13, 13', 13" (pin separators 13, receptacled separators 13', or protruding separators 13") are described as being permanently connected to the RF electrodes 12a, 12b, 12a', 12b', received in the receiving region 11a of the dielectric material 11, and soldered to a conductive contact point on the dielectric material 11. Alternatively, the separators 13, 13', 13" may be removably received in the receiving region 11a of the dielectric material 11. In an alternative embodiment, the separators 13, 13', 13" may be permanently bonded to the dielectric material 11, received in a receiving region of the RF electrode 12a, 12b, 12a', 12b', and soldered to the RF electrode 12a, 12b, 12a', 12b'.Alternatively, the separators 13, 13', 13" may be removably received in a receiving area of ​​the RF electrode 12a, 12b, 12a', 12b'. In an alternative embodiment, the separators 13, 13', 13" may be removably connected to both the dielectric material 11 and the RF electrode 12a, 12b, 12a', 12b'.

[0118] In the Fig. 5 to 10, 15 and 16, each separator 13, 13', 13" (pin separators 13, receptacle-type separators 13' or projecting separators 13") has a projecting portion 13b extending through a through-hole 11a in the thickness of the dielectric material 11. Alternatively, each separator 13, 13', 13" may be received in an opening of the dielectric material 11. The opening may extend only partially through the thickness of the dielectric material 11. For example, the separator 13, 13', 13" (pin separators 13, receptacled separators 13', or protruding separators 13") may be received in a recess on the inner surface of the dielectric material 11 (the planar surface of the dielectric material 11 that is located close to and opposite the respective RF electrode 12a, 12b, 12a', 12b'). The Fig. 5 to 10 and 15 show that the protruding portion 13b extends beyond the outer major surface of the dielectric material 11 when the RF electrode 12a, 12b, 12a', 12b' is bonded to the dielectric material 11. In an alternative embodiment, the protruding portion 13b of the separator 13, 13', 13" (pin separators 13, receptacled separators 13', or protruding separators 13") may be arranged flush with the dielectric material 11 when the RF electrode 12a, 12b, 12a', 12b' is bonded to the dielectric material 11.

[0119] In the Fig. In Figures 5 to 10, the DC electrodes 14 are shown as segmented. However, the DC electrodes 14 may also be non-segmented.

[0120] The Fig. Figures 5 to 10 describe that a single, segmented DC electrode 14 is provided on each dielectric material 11. Alternatively, multiple DC electrodes 14 may be provided on each dielectric material 11. If so, the multiple DC electrodes 14 may have a voltage gradient applied to them via a resistive divider.

[0121] The pin separators 13 of the Fig. 5 to 10 are described as having a disc-shaped head portion 13a and a cylindrical protruding portion 13b. However, the separators 13 may have any other suitable shape. For example, the head portion 13a and / or the protruding portion 13b may have a square or triangular cross-section. Furthermore, the head portion 13a may also be non-planar.

[0122] As in the Fig. 5 and Fig. 8, the diameter of each head portion 13a is similar to the width of the respective RF electrode 12a, 12b, 12a', 12b'. Typically, the centers of the head portions 13a are positioned directly along the central longitudinal axis of the RF electrodes 12a, 12b, 12a', 12b'. Alternatively, the diameter of each head portion 13a may be smaller or larger than the width of the RF electrode 12a, 12b, 12a', 12b'. Indeed, if the head portion 13a has a smaller diameter than the width of the RF electrode 12a, 12b, 12a', 12b', then the centers of the head portions 13a may or may not be positioned along the central longitudinal axis of the RF electrodes 12a, 12b, 12a', 12b'. For example, the centers of the head regions 13a may be positioned on either side of the central longitudinal axis of the RF electrodes 12a, 12b, 12a', 12b'.

[0123] For those in the Fig. In the embodiment shown in Figures 5 to 10, the pin separators 13 are described as being connected to the RF electrodes 12a, 12b, 12a', 12b' by welding the head portion 13a to the RF electrodes 12a, 12b, 12a', 12b'. However, other fastening means are also possible. For example, the pin separators 13 can be soldered to the RF electrodes 12a, 12b, 12a', 12b'. Alternatively, the pin separators 13 can be press-fitted into openings / recesses in the RF electrodes 12a, 12b, 12a', 12b'.

[0124] For those in the Fig. In the embodiment shown in Figures 5 to 10, 15, and 16, the projecting portions 13b of the separators 13, 13', 13" (pin separators 13, receptacle-type separators 13', or projecting separators 13") and / or the through-holes 11a may be threaded to retain the projecting portions 13b in the through-holes 11a. Alternatively, the projecting portions 13b of the separators 13, 13', 13" (pin separators 13, receptacle-type separators 13', or projecting separators 13") may be press-fitted into the through-holes 11a to retain the projecting portions 13b in the through-holes 11a.

[0125] For those in the Fig. 5 to 10 and Fig. 15 and Fig. In the embodiment shown in Figure 16, each protruding portion 13b of the pin separators 13 and the receptacle-equipped separators is described as extending orthogonally / perpendicular to the plane of the respective head portion 13a. However, each protruding portion 13b may instead extend at an oblique angle to the head portion 13a.

[0126] The separators 13, 13', 13" (pin separators 13, separators provided with a receptacle 13' or projecting separators 13") can be spacers / distance bolts.

[0127] For those in the Fig. 5 to 10 and Fig. 15 and Fig.In the embodiments shown in Figure 16, the separators 13, 13', 13" (pin separators 13, receptacle-type separators 13', or protruding separators 13") are preferably formed from a material with low dielectric losses (low loss factor Df = tan δ) so that the separators do not heat up in the presence of the RF field generated by the RF electrodes 12a, 12b, 12a', 12b'. This therefore avoids outgassing and undesirable changes to the analyte molecules. The separators 13, 13', 13" (pin separators 13, receptacle-type separators 13', or protruding separators 13") are preferably formed from a material with low electrical susceptibility (and thus low dielectric losses). Accordingly, the separators 13 are preferably electrically conductive and more preferably metallic.However, the separators 13 can also be formed from plastic, ceramic, quartz, and other dielectric materials with low dielectric losses (low loss factor Df). Preferably, the separators 13 are formed from a material with a loss factor Df of δ < 0.001, more preferably δ < 0.0005, and most preferably δ < 0.0003. For example, quartz with a loss factor of 0.0002 is a preferred material for the separators 13, 13', 13". A conductive connection is provided between the RF supply for the RF electrodes 12a, 12b, 12a', 12b' via such an insulating material of the separator 13, e.g., a conductive coating, a soldered connection, a wire bond, a conductive adhesive, etc. Forming a separator using a material with low dielectric losses is particularly preferred for embodiments with high RF voltages applied to the RF electrodes 12a, 12b, 12a', 12b'.

Claims

[1] An electrode arrangement (10, 10') for an ion trap, an ion filter, an ion guide, a reaction cell or an ion analyzer, the electrode arrangement (10, 10') comprising: an RF electrode (12a, 12b, 12a', 12b') mechanically connected to a dielectric material (11); wherein the RF electrode (12a, 12b, 12a', 12b') is mechanically connected to the dielectric material (11) by a plurality of separators (13, 13') that are spaced apart from one another and configured to define a gap between the RF electrode (12a, 12b, 12a', 12b') and the dielectric material (11), and wherein each of the plurality of separators (13, 13') comprises a projecting region (13b), and the dielectric material (11) comprises corresponding receiving regions (11a), such that when connecting the RF electrode to the dielectric material (11), the projecting region (13b) of each separator (13, 13') is received in the corresponding receiving region (11a) of the dielectric material (11), wherein the RF electrode (12a, 12b, 12a', 12b') has a surface opposite the dielectric material (11), wherein the electrode arrangement (10, 10') comprises at least one DC voltage electrode (14),which is positioned between the dielectric material (11) and the RF electrode (12a, 12b, 12a', 12b'), , characterized by that the DC electrode (14) extends over the dielectric material (11) such that at least a portion of the DC electrode (14) is located directly between the surface of the RF electrode (12a, 12b, 12a', 12b') and the dielectric material (11); and wherein the proportion of the surface area of ​​the surface of the RF electrode (12a, 12b, 12a', 12b') which is shielded from the dielectric material (11) by the DC voltage electrode (14) is at least 50%. [2] Electrode arrangement (10, 10') according to claim 1, wherein the DC voltage electrode (14) is segmented. [3] Electrode arrangement (10, 10') according to any preceding claim, wherein the plurality of separators (13, 13') are electrically conductive, wherein preferably the plurality of separators (13, 13') are metallic. [4] Electrode assembly (10, 10') according to any preceding claim, wherein the plurality of separators (13, 13') are spaced apart from one another along a surface of the RF electrode (12a, 12b, 12a', 12b'). [5] The electrode assembly (10, 10') of claim 1, wherein each projecting portion (13b) extends from the surface of the RF electrode (12a, 12b, 12a', 12b') opposite the dielectric material (11). [6] Electrode assembly (10, 10') according to claim 5, wherein each corresponding receiving region (11a) comprises an opening formed in the dielectric material (11). [7] Electrode assembly (10, 10') according to claim 6, wherein each opening is a through-hole (11a) extending through the dielectric material such that when connecting the RF electrode (12a, 12b, 12a', 12b') to the dielectric material (11), each projecting portion (13b) extends through the corresponding through-hole (11a). [8] Electrode arrangement (10, 10') according to claim 1, wherein the DC electrode (14) is positioned on the surface of the dielectric material (11) opposite the RF electrode (12a, 12b, 12a', 12b'). [9] Electrode assembly (10, 10') according to claim 8, wherein the DC electrode (14) extends along the entire surface of the dielectric material (11) to the opposite RF electrode (12a, 12b, 12a', 12b'), with the exception of exposed regions of the dielectric material (11), the exposed regions comprising the region of the dielectric material (11) that is in contact with and / or adjacent to each separator (13, 13') when the RF electrode (12a, 12b, 12a', 12b') is connected to the dielectric material (11). [10] Electrode assembly (10, 10') according to claim 9, wherein the exposed areas have grooves (11c) therein. [11] Electrode arrangement (10, 10') according to claim 1, wherein the RF electrode (12a, 12b, 12a', 12b'), the DC electrode (14) and the dielectric material (11) are arranged in parallel. [12] Electrode arrangement (10, 10') according to any preceding claim, wherein the dielectric material (11) is glass, ceramic or a printed circuit board. [13] An electrode assembly (10, 10') according to any preceding claim, wherein each separator (13, 13') is permanently attached to the RF electrode (12a, 12b, 12a', 12b'). [14] Electrode assembly (10, 10') according to claim 13, wherein each separator (13, 13') is welded to the RF electrode (12a, 12b, 12a', 12b'). [15] Electrode assembly (10, 10') according to any one of the preceding claims, wherein each separator (13, 13') comprises a head portion (13a) from which the projecting region (13b) extends, the head portion (13a) having a larger diameter than the projecting region (13b). [16] Electrode assembly (10, 10') according to claim 15, wherein the diameter of the corresponding receiving portion (11a) is equal to or larger than that of the projecting portion (13b) and smaller than that of the head portion (13a). [17] Electrode arrangement (10, 10') according to one of the preceding claims, wherein the RF electrode (12a, 12b, 12a', 12b') comprises a plurality of projecting regions (12c), and each of the separators (13, 13') comprises corresponding receptacles (13d), so that each projecting region (12c) is received in the corresponding receptacle (13d) when the RF electrode (12a, 12b, 12a', 12b') is connected to the separators (13, 13'). [18] An electrode arrangement (10, 10') for an ion trap, an ion filter, an ion guide, a reaction cell or an ion analyzer, the electrode arrangement comprising: an RF electrode (12a, 12b, 12a', 12b') mechanically connected to a dielectric material (11); wherein the RF electrode (12a, 12b, 12a', 12b') is mechanically connected to the dielectric material (11) by a plurality of separators (13, 13') that are spaced apart from each other and configured to define a gap between the RF electrode (12a, 12b, 12a', 12b') and the dielectric material (11), wherein the RF electrode (12a, 12b, 12a', 12b') comprises a plurality of projecting portions (12c), and each of the separators (13, 13') comprises a corresponding receptacle (13d), such that each projecting portion (12c) upon connecting the RF electrode (12a, 12b, 12a', 12b') to the separators (13, 13') in the corresponding receptacle (13d) is included. [19] Electrode assembly (10, 10') according to claim 17 or claim 18, wherein each projecting portion (12c) comprises a first portion in the plane of the RF electrode (12a, 12b, 12a', 12b') and a second portion at an angle to the plane of the RF electrode (12a, 12b, 12a', 12b'), at least a portion of the second portion being received in the corresponding receptacle (13d). [20] The electrode assembly (10, 10') of claim 19, wherein each projecting portion (12c) of the RF electrode (12a, 12b, 12a', 12b') includes a curved portion between the first portion and the second portion. [21] Electrode assembly (10, 10') according to any one of claims 18 to 20, wherein the receptacle (13d) comprises an opening extending therethrough such that upon connection of the RF electrode (12a, 12b, 12a', 12b') to the separator (13, 13') each projecting portion (12c) extends into the corresponding opening. [22] Electrode assembly (10, 10') according to any one of claims 18 to 21 when dependent on claim 15 or claim 16, wherein the receptacle (13d) forms part of the head portion (13a) of the separator (13, 13'). [23] An electrode assembly (10, 10') according to any preceding claim, wherein each separator (13, 13') is configured to be connected to an RF power supply. [24] The electrode assembly (10, 10') of any preceding claim, further comprising a second RF electrode (12a, 12b, 12a', 12b') connected to the dielectric material (11), wherein the second RF electrode (12a, 12b, 12a', 12b') is connected to the dielectric material (11) by a second plurality of separators (13, 13') spaced apart from each other and configured to define a gap between the second RF electrode (12a, 12b, 12a', 12b') and the dielectric material (11). [25] An electrode arrangement (10, 10') according to any preceding claim, wherein the electrode arrangement (10, 10') is a first such electrode arrangement (10, 10'), and a second such electrode arrangement (10, 10') is provided spaced from and parallel to the first such electrode arrangement (10, 10'), and the first and second such electrode arrangements (10, 10') form a multipole, the ion optical axis being defined between the first and second such electrode arrangements (10, 10'). [26] Ion guide comprising the electrode arrangement (10, 10') according to one of claims 1 to 25. [27] An ion filter comprising the electrode arrangement (10, 10') according to any one of claims 1 to 25. [28] Ion analyzer comprising the electrode arrangement (10, 10') according to one of claims 1 to 25. [29] An ion trap comprising the electrode arrangement (10, 10') according to any one of claims 1 to 25. [30] Ion trap according to claim 29, wherein the ion trap is a C-trap, a linear ion trap, a 3D ion trap, a magnetic trap, an electrostatic trap or a reaction cell, in particular an HCD cell. [31] A method of manufacturing the electrode assembly (10, 10') according to any one of claims 1 to 25, the method comprising the following series of steps: (i) mechanically connecting the RF electrode (12a, 12b, 12a', 12b') to the dielectric material (11) using the plurality of separators (13, 13') spaced apart from each other so as to define a gap between the RF electrode (12a, 12b, 12a', 12b') and the dielectric material (11); (i) cutting the RF electrode (12a, 12b, 12a', 12b') while the RF electrode (12a, 12b, 12a', 12b') is connected to the dielectric material (11) so as to reshape the RF electrode (12a, 12b, 12a', 12b'). [32] The method of claim 31, wherein prior to the step of cutting the RF electrode (12a, 12b, 12a', 12b') at least one DC electrode is provided on a surface of the dielectric material (11). [33] The method of claim 31 or 32, wherein the cutting of the RF electrode (12a, 12b, 12a', 12b') comprises a wire erosion process.

Images