GB483586A - Improvements in or relating to electron discharge devices - Google Patents

Abstract

483,586. Electron multipliers ; generating circuits. MARCONI'S WIRELESS TELEGRAPH CO., Ltd., and LINSELL, A. A. Oct. 26, 1936, No. 29095. [Classes 39 (i) and 40 (v)] Auxiliary electrodes 19, 20, Fig. 2, are located adjacent the multiplying electrodes 2, 3, (but not the last electrode 4) of an electron multiplier of the type in which accelerating electrodes 6 ... 9 are arranged opposite the cathode 1 and multiplying electrodes 2, 3, 4 and the electron paths are bent round by a suitable magnetic field. As the voltage on the electrodes is increased the current to the output electrode 12 rises to a maximum and then falls ; the auxiliary electrodes increase the sharpness of this maximum and render the tube more suitable for frequency-multiplying purposes. In Fig. 2, the auxiliary electrodes are inclined and are connected directly to the next multiplying electrode. In another form the auxiliary electrodes are parallel to, and behind the gaps between the multiplying electrodes. Separate external leads to the auxiliary electrodes may be provided. In an alternative modification, the auxiliary electrodes 21, 22, Fig. 5, are placed behind the edges of the output electrode 12. The frequency to be multiplied from source 13 is rectified at 14 and the half-wave rectified pulses developed across resistance 15 are applied to all the electrodes. In working near the maximum of the characteristic a frequency four times the input frequency is developed across the resonant circuit 18. The current collected by electrodes 21, 22 may be fed back through coils 23, 24 and the peak is thereby sharpened. The Provisional Specification describes also modifications in which the sharpening of the peak is attained by gradually increasing the size of the electrodes or the area of secondary emissive surface on each electrode. The secondary emissive material may be coated on the centre only or on the periphery only of the electrode.