GB2050048A - Improvements relating to electronmultiplier tubes - Google Patents

Abstract

A method of manufacturing an electronmultiplier tube includes the use of an electrically conductive assembly comprising a group of strip like, side-by-side conductors maintained in a predetermined, geometrical format, the conductors being mutually spaced by means of at least one removeable interlinking members 14-17 extending transversely of the group. The geometrical format is such that each conductor is capable of connecting a different dynode to its corresponding voltage source at the electronmultiplier "pinch". When the assembly has been positioned and the conductors have been fixed to connect each dynode to its corresponding voltage source, the interlinking member is removed. Different multiplier arrangements in which the dynodes are secured to insulating support members are described w.r.t. Figs. 1a, 2, 3a, b (not shown). Dimensions and materials are specified. <IMAGE>

Description

SPECIFICATION Improvements relating to electronmultiplier tubes This invention relates to electronmultiplier tubes and especially to the connections made between each electron multiplier dynode and its respective voltage source.

Typically the dynodes of a multistage electronmultiplier tube are maintained in a fixed, spaced relationship by common insulating support members, between which each dynode is supported at its ends.

During assembly of an electronmultiplier tube it is necessary to make an electrical connection between each dynode and its respective voltage source which is usually positioned at the electronmultiplier "pinch" at one end of the tube. Hitherto this arrangement has necessitated the preparation of individual pieces of wire of different lengths and shapes, for connection between each dynode and the "pinch" a procedure which has proved to be both inconvenient and time consuming.

It is therefore an object of the present invention to provide an improved arrangement for connecting each dynode of an electron multiplier tube to its respective voltage source.

According to one aspect of the invention there is provided a method of manufacturing an electron multiplier tube including the steps of: (a) supporting a plurality of dynodes at predetermined attitudes and in predetermined locations within the tube, and (b) establishing electrical connection between each dynode and a respective connector pin which traverses the envelope of the tube; the said steps including the following substeps: (i) securing said dynodes to at least one support member formed of, or coated with, electrically insulating material, by securing portions extending from said dynodes in apertures formed in said support member, (ii) providing an electrically conductive assembly comprising a group of strip-like, sideby-side conductors maintained in a predetermined geometrical format, with the conductors of the group mutually spaced, by means of at least one removable, interlinking member extending transversely of the group of conductors, (iii) securing one end of each of the conductors of the group to a respective dynode and the other end of each of said conductors to a connector pin associated with the corresponding dynode, without substantially disturbing said geometrical format and (iv) removing said interlinking member.

According to another aspect of the invention there is provided an electrically conductive assembly suitable for use in the abovedescribed method the assembly comprising a group of strip-like, side-by-side conductors maintained in a predetermined geometrical format, with the conductors of the group mutually spaced, by means of at least one removable interlinking member extending transversely of the group of conductors.

The strip-like members may have substantially the same width and separation. The width of each strip-like member may lie between 0.1 mum and 2mm.

According to a yet further aspect of the invention there is provided an electron multiplier tube manufactured by the above-described method.

In order that the invention may be more readily understood specific embodiments thereof are now described, by way of example, by reference to the accompanying drawings of which, Figure la illustrates schematically an arrangement of dynodes each dynode having an attached conductive tape, Figure 1b illustrates a conductive assembly of the present invention suitable for use with an arrangement of dynodes of the type shown in Fig. la and, Figure 2 and Figures 3a and 3b illustrate alternative dynode arrangements and conductive tapes associated therewith.

Fig. 1 a of the drawings illustrates one arrangement for supporting the dynodes of an electronmultiplier tube between opposed, insulating support members. For clarity only two dynodes 1 and 2, are shown in an exploded view. The support members 3 and 4, which may typically be made of ceramic are castellated so that during construction dynode tabs, such as 5 and 6, formed on or attached to the dynodes may be simply folded around the appropriate castellations for support. At the opposite end of the dynode a more positive connection is provided by riveting the tabs to the support through relatively narrow castellations therein.In addition, and in accordance with the present invention, electrically conductive tapes, indicated at 7 and 8 in Fig. la, are riveted in the same operation to the outer face of the support member, so that each tape makes electrical contact with the associated dynode. These tapes provide the electrical connection between each dynode and the respective voltage source at the pinch (not shown in the Figure). In accordance with the present invention the conductive tapes used for all or at least a group of dynodes are provided in a single, conductive assembly. Conductive assemblies, suitable for use with an eight stage dynode system, of the kind described above, are illustrated in Fig.

1 b. Each assembly, 10 or 11, is suitable for connecting four different dynodes to their respective voltage sources. Each assembly com prises four, spaced conductive tapes, a to d, for assembly 10 and, e to h, for assembly 11, which are joined at their ends by separable interlinking members 14, 1 5 and 1 6, 1 7 respectively. In an alternative example each assembly may comprise only one separable interlinking member.

The relative dispositions of the tapes in the assembly are such that each tape is capable of making electrical contact with a different dynode and connecting it to the corresponding voltage source connector pin at the "pinch".

As described above, once the conductive assembly has been positioned against the outer face of the dynode support member each tape is riveted to the corresponding dynode tab through a narrow castellation, and for further security each tape may also be riveted to the support at another position (at the points i to I, for example). Once the conductive tapes have been riveted in position the separable interlinking members are no longer required and are removed.

In the example of Fig. 1 b each assembly is suitable for contacting four adjacent dynodes but in an alternative arrangement the conductive tapes of which the assembly is comprised, may be arranged to contact alternate dynodes.

Other arrangements of conductive tapes may alternatively be used and may be suitable for use with corresponding configurations of dynodes. Each conductive assembly, 10 or 11, is made as a single piece part by chemical milling or by punching a flat foil, typically of copper or copper nickel of a thickness typically between 8.05mum and 0.25mm. The tapes are spaced apart and are maintained in a fixed configuration, appropriate for a particular arrangement of dynodes, by the separable cross linking members, 14 and 1 5 or 1 6 and 17, for example, which are removed after assembly. Typically each tape has a uniform width (of between 0.1 mm and 2mm) and the separation between the tapes may be equai their width.

In this description the constructional details of the dynodes have been omitted for reasons of clarity, but as will be appreciated by a person skilled in the art each dynode is appropriately shaped to guide the secondary electrons generated at its surface to an adjacent dynode at a higher potential. In particular, the dynodes shown schematically at 1 or 2 in Fig.

1 a may comprise a plurality of parallel slats which permit electrons generated at their secondary emitting surfaces to pass through the dynode towards the next dynode-an arrangement which is sometimes referred to as the "Venetian blind" type of construction.

An alternative arrangement is shown in Fig.

2 in which the dynodes are of the shaped focussing type. In this example the conductive assembly shown, in part, at 20 is arranged at the support member to connect alternate dynodes to their respective voltage sources.

In alternative configurations, shown, in part, in Figs. 3a and 3b, each dynode 30 of an electron multiplier arrangement has a pair of opposed supporting side elements of the kind shown at 31. In one configuration, shown in Fig. 3a, a conductive tape 32 is riveted to an associated dynode tab through a narrow castellation in the insulating support 33, as described earlier. In another arrangement shown in Fig. 3b the conductive tape 32 has a relatively broad section 34 having slots through which corresponding dynode tabs, 35 and 36, are accepted. The tabs may then be either soldered to the tape or twisted into an S shape to provide a firm, rigid assembly. Typically the inwardly facing surfaces of the side elements are coated with a non emissive material (aqua dag, for example) to reduce possible noise effects in the output signal.

The use of a conductive assembly of the kind described above, for connecting each dynode to its respective voltage source, is both convenient and time saving.

Claims (7)

1. A method of manufacturing an electron multiplier tube including the steps of: (a) supporting a plurality of dynodes at predetermined attitudes and in predetermined locations within the tube, and (b) establishing electrical connection between each dynode and a respective conector pin which traverses the envelope of the tube; the said steps including the following substeps: (i) securing said dynodes to at least one support member formed of, or coated with, electrically insulating material, by securing portions extending from said dynodes in apertures formed in said support member, (ii) providing an electrically conductive assembly comprising a group of strip-like, sideby-side conductors maintained in a predetermined geometrical format, with the conductors of the group mutually spaced, by means of at least one removable, interlinking member extending transversely of the group of conductors, (iii) securing one end of each of the conductors of the group to a respective dynode and the other end of each of said conductors to a connector pin associated with the corresponding dynode, without substantially disturbing said geometrical format and (iv) removing said interlinking member.

2. A method according to Claim 1 including providing an electrically conductive assembly in which each strip-like side by side conductor has substantially the same width and separation.

3. A method according to Claim 2 wherein the width of each strip-like side by side conductor lies between 0.1 mm and 2mm.

4. An electrically conductive assembly suitable for use in a method according to any one of claims 1 to 3 the assembly comprising a group of strip-like side by side conductors maintained in a predetermined geometrical format with the conductors of the group mutually spaced by means of at least one removeable interlinking member extending transversely of the group of conductors.

5. An electron multiplier tube manufactured by the method according to any one of claims 1 to 3.

6. A method of manufacturing an electron multiplier tube substantially as hereinbefore described.

7. An electrically conductive assembly substantially as hereinbefore described by ref erenceto Fig. 1 b.