US2280449A - Electron multiplier - Google Patents

Description

April 21, 1942. zsc

ELECTRON MULTIPLIER Filed July 29, 1959 mi W W r. H i 6 Patented Apr. 21, 1942 ELECTRON MULTIPLIER Herbert Pietzsch, Berlin, Germany, assignor to O. Lorenz Aktiengesellschaft, Berlin-Tempelhof, Germany, a company Application July 29, 1939, Serial No. 287,187 In Germany August 3, 1938 1 Claim.

In electron multipliers electrons emitted from the cathode are directed by a plurality of successive electrodes, from which secondary emission takes place, for the purpose of accelerating the electrons, a plurality of mutually parallel fine-mesh grids are generally used, which grids one after the other filter the electron stream. Thus the potential of each grid must become greater from element to element. The efiiciency of an electron multiplier depends largely upon the proper choice of potential to be applied to each grid, and these values are best determined experimentally. Since every grid must be furnished with a potential and high-efficiency electron multipliers contain a great number of grids, many control leads must be fused into the walls of the vacuum envelope.

My invention will be more readily understood when considered in conjunction with the following description and drawing, which shows the material of the invention as applied to an electron multiplier. Fig. 1 shows a side view of the electron multiplier tube, and Fig. 2 shows a view of the base of the tube of Fig. 1.

The invention proposes that the afore-mentioned numerous control leads be regularly arranged on the circumference of concentric circles. Since in the future the efficiency of an electron multiplier will depend upon how well the base leads are insulated, it is obvious that the distance between two or more leads will be increased by employing a plurality of concentric circles to dispose the leads in the design of a base.

A possible application of the invention is illustrated in the accompanying drawing, in which the glass envelope I is shown to include a large number of electrodes 2, 3 to H. The latter are fine-mesh grids held in place by the glass rods A and B. Each of these electrodes is fed by a corresponding lead wire Z2 to Z! I, which is led externally to the front end or base of the enclosing vessel. Two concentric circles, as mentioned above for arranging the control wires, are illustrated in two separate stages of a cup-shaped base on the left side of the figure. It is naturally possible to employ more of said concentric stages in different levels when a larger number of control leads necessitates it.

What is claimed is:

A multi-element electron discharge tube including a vessel having a throat portion, an electrode system in said vessel and lead-in conductors to the various electrodes of said electrode system, the base end of said throat portion being formed with a series of successively smaller concentric integral cup-shaped portions, presenting generally radially extending annular surfaces, said lead-in conductors passing through said radially extending annular surfaces.

HERBERT PIETZSCH.

Images