Multipole device and manufacturing method

Abstract

A method of manufacturing a multipole device includes the steps of: (a) forming an intermediate device by assembling a plurality of components including a plurality of precursor multipole electrodes, wherein the plurality of precursor multipole electrodes in the assembled device extend along and are distributed around a central axis; (b) forming a multipole device from the intermediate device by machining the precursor multipole electrodes within the intermediate device to provide a plurality of multipole electrodes having a predetermined spatial relationship; wherein a first component of the multipole device that includes a multipole electrode is attached non-permanently to a second component of the multipole device, the first component including a first alignment formation, and the second component including a second alignment portion configured to engage with the first alignment formation on the first component so as to facilitate alignment of the first component and the second component when the first component and the second component are attached, thereby allowing the first component to be detached from and then reattached to the second component while retaining the predetermined spatial relationship between the plurality of multipole electrodes.

Claims

1. A method of manufacturing a multipole device, the method including the steps of: (a) forming an intermediate device by assembling a plurality of components including a plurality of precursor multipole electrodes, wherein the precursor electrodes each comprise a prism with a trapezoidal cross-section having a rear surface, two oblique surfaces and a front surface which is flat such that the four precursor electrodes form a channel running between them, the channel having a square cross-section, wherein the plurality of precursor multipole electrodes in the assembled device extend along and are distributed around a central axis wherein a first component of the intermediate device includes a first alignment formation and a second component of the intermediate device includes a second alignment formation, the method including positioning the first component of the intermediate device and second component of the intermediate device by using the first and second alignment formations so that the first component of the intermediate device can be detached from and then reattached to the second component of the intermediate device while retaining a predetermined spatial relationship within the intermediate device; (b) forming a multipole device from the intermediate device by machining the precursor multipole electrodes within the intermediate device to provide a plurality of multipole electrodes having said predetermined spatial relationship; wherein a first component of the multipole device that includes a multipole electrode is attached non-permanently to a second component of the multipole device that includes a multipole electrode, the first component of the multipole device including said first alignment formation on a said oblique surface of a first electrode of the precursor multipole electrodes, and the second component of the multipole device including said second alignment formation on a said oblique surface of a second electrode of the precursor multipole electrodes configured to engage with the first alignment formation so as to facilitate alignment of the first component of the multipole device and the second component of the multipole device when the first component of the multipole device and the second component of the multipole device are attached, thereby allowing the first component of the multipole device to be detached from and then reattached to the second component of the multipole device while retaining the predetermined spatial relationship between the plurality of multipole electrodes.

2. A method according to claim 1, wherein in step (b) the machining is in the form of wire electrical discharge machining.

3. A method according to claim 1, further including the steps of: (c) disassembling the plurality of multipole electrodes; (d) performing at least one processing step on the plurality of multipole electrodes, the at least one processing step including one or more of: cleaning the plurality of multiple electrodes, polishing surfaces of the plurality of multiple electrodes, and plating of the plurality of multiple electrodes; and (e) reassembling the plurality of multipole electrodes to reform the multipole device, in which the plurality of multipole electrodes have the same predetermined spatial relationship.

4. A method according to claim 1, wherein the position of any point on a surface of the second component is substantially the same before and after detachment and reattachment of the first component and the second component, relative to a coordinate system which is fixed with respect to the first component.

5. A method according to claim 1, wherein the first alignment formation and the second alignment formation together form at least part of a kinematic alignment formation arranged to constrain the motion of the first component relative to the second component once in each degree of freedom.

6. A method according to claim 5, wherein the first alignment formation is arranged to contact the second alignment formation in only six locations, when the first component is attached to the second component.

7. A method according to claim 1, wherein the first alignment formation includes a notch, having two flat surfaces.

8. A method according to claim 7, wherein the second alignment formation includes a spherical or spheroidal structure.

9. A method according to claim 8, wherein the first alignment formation includes three notches, and the second alignment formation includes three spherical or spheroidal structures, wherein each of the notches is arranged to engage with a respective one of the spherical or spheroidal structures when the first component and the second component are attached.

10. A method according to claim 1, wherein the first alignment formation is configured to engage indirectly with the second alignment formation via one or more intermediary components, such that both the first alignment formation and the second alignment formation are in contact with the intermediary component.

11. A method according to claim 10, wherein when the first component is attached to the second component, each of the first alignment formation and the second alignment formation contact the one or more intermediary components in only six locations.

12. A method according to claim 11, wherein the intermediary components are in the form of spherical or spheroidal structures made from an electrically insulating material.

13. A method according to claim 1, wherein the plurality of components include a main body including two or more integrally formed poles, and two or more other poles configured to be situated within the main body.

14. A method according to claim 1, wherein the quadrupole device is one of: a quadrupole ion guide, a segmented quadrupole ion guide, a quadrupole mass filter, a segmented quadrupole mass filter, a linear ion trap, or a segmented linear ion trap.

15. A multipole device, including: a plurality of components including a plurality of multipole electrodes extending along and distributed around a central axis, the plurality of multipole electrodes having a predetermined spatial relationship; wherein a first component of the multipole device that includes a multipole electrode is attached non-permanently to a second component of the multipole device that includes a multipole electrode, the first component including a first alignment formation, and the second component including a second alignment formation configured to engage with the first alignment formation on the first component so as to facilitate alignment of the first component and the second component when the first component to be detached from and then reattached to the second component while retaining the predetermined spatial relationship between the plurality of multipole electrodes; wherein the first component of the multipole device and the second component of the multipole device are machined components formed by providing an intermediate device comprising an assembly of a plurality of components including a plurality of precursor multipole electrodes including a first component of an intermediate device including said first alignment formation and a second component of the intermediate device including said second alignment formation, positioning the first component of the intermediate device and second component of the intermediate device by using the first and second alignment formations so that the first component of the intermediate device can be detached from and then reattached to the second component of the intermediate device while retaining a predetermined spatial relationship within the intermediate device, and matching the precursor multipole electrodes within the intermediate device to provide a plurality of multipole electrodes having said predetermined spatial relationship, wherein the precursor electrodes each comprise a prism with a trapezoidal cross-section; wherein the first alignment formation is on a said oblique surface of a first electrode of the plurality of precursor electrodes, and the second alignment formation is on a said oblique surface of a second electrode of the plurality of precursor electrodes.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which:

(2) FIGS. 1A and 1B show a prior art quadrupole device.

(3) FIGS. 2A and 2B show prior art quadrupole devices in place in segmented ion traps.

(4) FIGS. 3A to 3D show the manufacturing process of the present invention, and the finished quadrupole device.

(5) FIGS. 4A and 4B illustrate examples of kinematic alignment.

(6) FIGS. 5A to 5D show an alternative example of a device which may be produced using the manufacturing method of the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS

(7) FIGS. 3A to 3D illustrate an embodiment of the method of the present invention and the resulting product, in which the method is used to prepare a quadrupole device 300 having hyperbolic poles.

(8) FIG. 3A shows three precursor electrode structures 304, 306, 308. Main body 304 is a largely cuboidal structure having bevelled edges 310. There is a channel 312 passing through the centre of the main body 304, the channel 312 having a bow-tie shaped cross section, with two lobes 311a, 311b, and running along the full length of the main body 304. The surfaces 313 where the top and bottom walls of channel 312 are at their closest are hyperbolic surfaces. These surfaces 313 form two of the four poles when the quadrupole device 300 is fully assembled. The side walls 314 of the main body 304 have a hole 316 extending therethrough, the hole 316 opening into the channel 312.

(9) Electrodes 306, 308 are substantially triangular prismatic in shape, and are each shaped to fit in a respective lobe 311 of the channel 312. The inner surfaces 318a, 318b of electrodes 306, 308 are hyperbolic in shape, and when the quadrupole device 300 is assembled, form the remaining two poles along with surfaces 313. The flat surfaces 320a, 320b of electrodes 306, 308 include holes 322, which, when electrodes 306, 308 are in place inside channel 312, align with the holes 316 in the side walls 314 of the main body 304.

(10) Each of the vertical edges 324 of the front opening of the channel 312 includes a V-shaped notch 326. The corresponding edges 328 on the electrodes 306, 308 include corresponding notches 330. The notches 326, 330 are located such that when the electrodes 306, 308 are fitted in place inside the channel 312, the notches 326, 330 are spatially adjacent.

(11) Assembly of the device 300 will now be described. Electrodes 306, 308 are slotted through respective lobes 311a, 311b of the channel 312 until holes 316, 322 are aligned. Then, insulating balls 332 are placed into the spaces 334, 336 formed by the alignment of the notches 326 of the main body 304 and notches 330 of the electrodes 306, 308. When the insulating balls 332 are placed into said spaces 334, 336, each of the surfaces of each V-shaped notch 326, 330 contacts the respective insulating ball 332 once. Though not shown in the drawings, there are two additional notches 338 on the back edge 340 of the electrodes 306, 308, and corresponding notches in the back edge of the main body 304. These also line up when the electrodes 306, 308 are in place inside the channel 312 of the main body 304, to generate two additional spaces, into each of which another insulating ball 332 is placed. This ensures that the notches 326 on the main body 304 engage with the notches 330 of each of the electrodes 306, 308 in six locations, and kinematic alignment may be achieved between the main body 304 and each of the electrodes 306 and 308. Once the notches 326, 330 and insulating balls 332 are used to correctly align the main body 304 and electrodes 306, 308, a fastener 342 and washer/bush 344 may be used to secure the pieces in place, as shown in FIG. 3B.

(12) Once the pieces have been assembled into device 346, as shown in FIG. 3B, the surfaces of the electrodes 304, 306, 308 can be machined by wire-EDM, using wire 348. This highly accurate technique, which takes place while the pieces are assembled, ensures that the surfaces of the electrodes have exactly the required geometry. Thereafter, the pieces making up newly-machined device 346 can be disassembled for additional processing such as cleaning, polishing and electroplating. Then, by reassembling the electrodes 304, 306, 308 using the notches 326, 330 and insulating balls 332 as before, it is possible to arrange the pieces into substantially exactly the same geometry as they had immediately after machining, as shown in FIG. 38. This is possible due to the kinetic alignment of the pieces. Optionally, the component electrodes 306, 308 may be marked to simplify replacement in the same position within the electrode 304.

(13) FIG. 3C shows a side view of the device 346 shown in FIG. 38, and FIG. 3D shows a cross section through line A-A of FIG. 3C, which shows all three notches 326 containing the insulating balls 332. FIG. 3D highlights the point that the centrelines of the V-shaped notches 326 should intersect at the coupling centroid C, where the fastener 342 is located. The stiffness of the assembly is then equal in all directions when the insulating balls 332 intersect the V-shaped notches 326 at 45°.

(14) FIGS. 4A and 48 illustrate kinematic alignment. FIG. 4A shows a simple example, including two pieces 402, 404. Piece 402 has three arms 406, each having a sphere of material 408 located on the bottom surface of the arm 408. Upper surface 410 of piece 404 includes three V-shaped notches 412, each groove having two surfaces 414, 416 intersecting at approximately 45°. When piece 402 is lowered onto piece 404, the spheres 408 each sit in the respective V-shaped notches, so that each surface 414, 416 of each V-shaped notch 412 contacts the corresponding sphere 408 once only, giving rise to six points of contact, and therefore to a kinematic alignment. The surfaces of each V-shaped notch 412 preferably contacts its corresponding sphere 408 substantially tangentially.

(15) FIG. 48 shows a slightly more complicated example of kinematic alignment, having pieces 402′, 404′. Piece 402′ has the same features as piece 402 in FIG. 4A. However, in FIG. 48, piece 404′ has three notches 410a′, 410b′, 410c′ which are different. Specifically, notch 410a′ includes three surfaces 418′, notch 410b′ includes two surfaces 420′, and notch 410c′ includes just a flat surface 422′. When the piece 402′ is lowered towards the piece 404′, each of the spheres 408′ engages with the notches 410a′, 410b′, 410c′. Once again, this gives rise to six points of contact, again leading to kinematic alignment, albeit differently from in FIG. 4A.

(16) FIGS. 5A to 5D show an alternative embodiment of a quadrupole device that may be manufactured according to the method of the first aspect of the invention. In contrast to the embodiment shown in FIGS. 3A to 3D, the device 500 shown in FIGS. 5A to 5D is made of four separate electrodes 502, 504, 506, 508. Whereas the electrodes 304, 306, 308 in device 300 of FIGS. 3A to 3D had hyperbolic surfaces, the electrodes 502, 504, 506, 508 have flat surfaces, to form a channel 510 running between them, the channel 510 having a square cross-section.

(17) The four electrodes 502, 504, 506, 508 are substantially identical, so only electrode 502 will be described here. To avoid crowding of the drawings, only this electrode 502 is labelled, but it is clear that the same description and labelling applies equally well for the remaining three electrodes 504, 506, 508.

(18) Electrode 502 is a prism with a trapezoidal cross-section, having a front surface 511, a rear surface 512, and two oblique surfaces 514, 516. As best shown in FIG. 70, each of the oblique surfaces 514, 516 includes three V-shaped notches 518, 520, 522, each having two flat surfaces intersecting at approximately 45°. The centroid C is the location where the three invisible lines extending from and parallel to the V-groove meet. This is discussed in more depth shortly, with reference to fastening.

(19) The electrode 502 includes two bores 524, 526. First bore 524 runs from the rear surface 512 to oblique surface 514. The rear surface end of bore 524 has a widened portion 528. Second bore 526 also runs from the rear surface 512 to oblique surface 516, and has a constant cross-section.

(20) The electrodes 502, 504, 506, 508 are assembled, as shown, so that the notches 518, 520, 522 on the oblique surfaces 514, 516 of electrode 502 line up with corresponding notches on each of the adjacent electrodes 504, 506. The same applies for each of electrodes 504, 506, 508. An insulating ball 530 is located in each of the twelve spaces formed by the alignment of the notches on adjacent electrodes 502, 504, 506, 508. At each meeting of oblique surfaces in the device 500, the insulating ball contacts each of the electrodes six times, ensuring a kinematic alignment between the two contacting electrodes.

(21) The first bore 524 of e.g. electrode 502 is arranged to align with the second bore 526 of adjacent electrode 506, and a fastener 532 is passed through the bores 524, 526 to secure the electrodes together. Similarly, the second bore 526 of electrode 502 is arranged to align with the first bore 524 of adjacent electrode 504, and they are joined by another fastener 532. The same applies for electrodes 504, 506 and 508.

(22) The notches 518, 520, 522 are arranged on the oblique surfaces 514, 516 of e.g. electrode 502 so that the centroid C is located where the bores 524, 526 emerge. In this way, each of the insulating balls 530 receives approximately equal stress.

(23) The features disclosed in the foregoing description, or in the following claims, or in the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for obtaining the disclosed results, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

(24) While the invention has been described in conjunction with the exemplary embodiments described above, many equivalent modifications and variations will be apparent to those skilled in the art when given this disclosure. Accordingly, the exemplary embodiments of the invention set forth above are considered to be illustrative and not limiting. Various changes to the described embodiments may be made without departing from the spirit and scope of the invention.

(25) For the avoidance of any doubt, any theoretical explanations provided herein are provided for the purposes of improving the understanding of a reader. The inventors do not wish to be bound by any of these theoretical explanations.

(26) Any section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described.

(27) Throughout this specification, including the claims which follow, unless the context requires otherwise, the word “comprise” and “include”, and variations such as “comprises”, “comprising”, and “including” will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

(28) It must be noted that, as used in the specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by the use of the antecedent “about,” it will be understood that the particular value forms another embodiment. The term “about” in relation to a numerical value is optional and means for example +/−10%.

(29) All references referred to above are hereby incorporated by reference.

(30) Aspects or examples of the invention may be defined according to the following numbered Paragraphs:

(31) Paragraph 1: A method of manufacturing a multipole device, the method including the steps of: (a) forming an intermediate device by assembling a plurality of components including a plurality of precursor multipole electrodes, wherein the plurality of precursor multipole electrodes in the assembled device extend along and are distributed around a central axis; (b) forming a multipole device from the intermediate device by machining the precursor multipole electrodes within the intermediate device to provide a plurality of multipole electrodes having a predetermined spatial relationship; wherein a first component of the multipole device that includes a multipole electrode is attached non-permanently to a second component of the multipole device, the first component including a first alignment formation, and the second component including a second alignment portion configured to engage with the first alignment formation on the first component so as to facilitate alignment of the first component and the second component when the first component and the second component are attached, thereby allowing the first component to be detached from and then reattached to the second component while retaining the predetermined spatial relationship between the plurality of multipole electrodes.

(32) Paragraph 2: A method according to Paragraph 1, wherein in step (b) the machining is in the form of wire electrical discharge machining.

(33) Paragraph 3: A method according to Paragraph 1 or Paragraph 2, further including the steps of: (c) disassembling the plurality of multipole electrodes; (d) performing at least one processing step on the plurality of multipole electrodes, the at least one processing step including one or more of: cleaning the plurality of multiple electrodes, polishing surfaces of the plurality of multiple electrodes, and plating of the plurality of multiple electrodes; and (e) reassembling the plurality of multipole electrodes to reform the multipole device, in which the plurality of multipole electrodes have the same predetermined spatial relationship.

(34) Paragraph 4: A method according to any one of Paragraphs 1 to 3, wherein the position of any point on a surface of the second component is substantially the same before and after detachment and reattachment of the first component and the second component, relative to a coordinate system which is fixed with respect to the first component.

(35) Paragraph 5: A method according to any one of Paragraphs 1 to 4, wherein the first alignment formation and the second alignment formation together form at least part of a kinematic alignment formation arranged to constrain the motion of the first component relative to the second component once in each degree of freedom.

(36) Paragraph 6: A method according to Paragraph 5, wherein the first alignment formation is arranged to contact the second alignment formation in only six locations, when the first component is attached to the second component.

(37) Paragraph 7: A method according to any one of Paragraphs 1 to 6, wherein the first alignment formation includes a notch, having two flat surfaces.

(38) Paragraph 8: A method according to Paragraph 7, wherein the second alignment formation includes a spherical or spheroidal structure.

(39) Paragraph 9: A method according to Paragraph 8, wherein the first alignment formation includes three notches, and the second alignment formation includes three spherical or spheroidal structures, wherein each of the notches is arranged to engage with a respective one of the spherical or spheroidal structures when the first component and the second component are attached.

(40) Paragraph 10: A method according to any one of Paragraphs 1 to 5, wherein the first alignment formation is configured to engage indirectly with the second alignment formation via one or more intermediary components, such that both the first alignment formation and the second alignment formation are in contact with the intermediary component.

(41) Paragraph 11: A method according to Paragraph 10, wherein when the first component is attached to the second component, each of the first alignment formation and the second alignment formation contact the one or more intermediary components in only six locations.

(42) Paragraph 12: A method according to Paragraph 11, wherein the intermediary components are in the form of spherical or spheroidal structures made from an electrically insulating material.

(43) Paragraph 13: A method according to any one of Paragraphs 1 to 12, wherein the plurality of components include a main body including two or more integrally formed poles, and two or more other poles configured to be situated within the main body.

(44) Paragraph 14: A method according to any one of Paragraphs 1 to 13, wherein the quadrupole device is one of: a quadrupole ion guide, a segmented quadrupole ion guide, a quadrupole mass filter, a segmented quadrupole mass filter, a linear ion trap, or a segmented linear ion trap.

(45) Paragraph 15: A multipole device, including: a plurality of components including a plurality of multipole electrodes extending along and distributed around a central axis, the plurality of multipole electrodes having a predetermined spatial relationship; wherein a first component of the multipole device that includes a multipole electrode is attached non-permanently to a second component of the multipole device, the first component including a first alignment formation, and the second component including a second alignment portion configured to engage with the first alignment formation on the first component so as to facilitate alignment of the first component and the second component when the first component and the second component are attached, thereby allowing the first component to be detached from and then reattached to the second component while retaining the predetermined spatial relationship between the plurality of multipole electrodes.