Electric lamp or space discharge component or device manufacturi – Process – Electrode making
Patent
1999-02-03
2000-08-15
Ramsey, Kenneth J.
Electric lamp or space discharge component or device manufacturi
Process
Electrode making
250292, H01J 4942, H01J 914
Patent
active
061027634
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The invention relates to a process for producing a quadrupole electrode arrangement and to a quadrupole electrode arrangement and a mass spectrometer.
STATE OF THE ART
Mass spectrometers are known in a variety of designs and are used for the analysis of chemical structures (cf e.g. U.S. Pat. No. 5,389,785, U.S. Pat. No. 5,298,745, U.S. Pat. No. 4,949,047, U.S. Pat. No. 4,885,470, U.S. Pat. No. 4,158,771 or U.S. Pat. No. 3,757,115). In principle, such instruments have an ion source, one (or more) ion filters and an ion detector. The gaseous ions are selected by the ion filter, which is typically formed of a quadrupole electrode arrangement with hyperbolically shaped surfaces. It is important for the hyperbolic surfaces to be made with very high precision and to be the right distance apart. In particular, precise positioning of the electrode surfaces has presented considerable difficulties hitherto.
DESCRIPTION OF THE INVENTION
The object of the invention is to provide a process for producing quadrupole electrode arrangements for mass spectrometers and the like which affords a high precision of the electrode arrangement while incurring the lowest possible expenditure on assembly.
The solution according to the invention is defined by the features of claim 1. The quadrupole is thus produced essentially from two shaped parts, each of which has two electrode surfaces machined out of it and at least one coupling surface. The two parts are shaped so that they can be placed directly against one another and joined together via the coupling surfaces. In the joined state, the two electrode pairs are exactly the right distance apart. The invention makes use, inter alia, of the fact that an individual shaped part can be produced with very high precision, e.g. by turning, milling and/or grinding. Machining two electrode surfaces out of one shaped part ensures that at least these two electrode surfaces are the right distance apart.
In a preferred embodiment, the two shaped parts are formed essentially of a plate-shaped carrier and a shaped block fixed thereto. The carrier is made of an insulating material, e.g. glass, and the block is made e.g. of a conducting material, for example stainless steel or aluminum. In the manufacturing process according to the invention, the block is fixed to the carrier in the raw state (i.e. as a blank) and then machined. Accordingly, for example, half of the quadrupole interior chamber is hollowed out of a steel plate by turning so that the interior chamber of the quadrupole electrode arrangement is created when the two parts are joined together. Feed lines can also be attached to the steel plate for evacuation of the interior chamber. The important aspect is that two electrode surfaces and a coupling surface can be produced in a single chucking.
Instead of a metal plate, it is also possible to use a ceramic plate; after the electrode surfaces have been shaped, this is selectively provided with a conducting layer (of copper, gold, platinum etc.).
The two shaped parts are advantageously formed with mirror symmetry. The process is particularly suitable for producing ion filters curved in the shape of a circular arc. Precision lathes are particularly good at producing circular shapes. However, the invention is also advantageous in the case of linear electrode arrangements.
So that two disk-shaped parts can be joined together with precision, each one is provided e.g. with a central bore. The two carriers can be mutually aligned with an expanding arbor.
With a quadrupole electrode arrangement produced according to the invention, it is also easy to seal the interior chamber between the electrodes so that the required high vacuum can subsequently be created. It is also possible to mill radial slots in the plates, into which ion lenses can be inserted at a later stage.
A mass spectrometer according to the invention comprises an ion source, a quadrupole electrode arrangement with electrodes curved in the shape of a circular arc, and a detector. There is also a vacuum pump for
REFERENCES:
patent: 4158771 (1979-06-01), Beeck et al.
patent: 5559327 (1996-09-01), Steiner
Cueni Hansjorg
Scherrer Heiner
LandOfFree
Process for producing a quadrupole electrode arrangement does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for producing a quadrupole electrode arrangement, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for producing a quadrupole electrode arrangement will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2000938