GB464413A - Improvements in or relating to electron-discharge devices - Google Patents

Abstract

464,413. Cathocle-ray tubes. KLEMPERER, O. Oct. 16, 1935, No. 28644. [Class 39 (i)] An electron-multiplier is provided with means for excluding from the electron beam all electrons having a velocity outside a predetermined range ; for this purpose the beam is deflected and passed through an aperture in a screen which stops all electrons deflected by more or less than a certain amount : the invention is stated to be especially applicable to the apparatus described in Specification 443,777. Fig. 2 shows an arrangement comprising a cathode 1, an accelerator grid 2 and a control grid 6. The electrons which pass an opening in a diaphragm 3 are deflected by arcuate plates 8 and 9 and these deflected to the desired extent pass through an opening in a diaphragm 5; dimensions and voltages of apparatus for separating electrons having a velocity of 20 volts. from those having a velocity of 20À3 volts are given. Other arrangements are described, one of which is shown in Fig. 4, in which the beam as a whole is not deflected. Electrons from the cathode 1 are accelerated and decelerated by electrodes 2 and 12 formed as cylinders with apertured ends and a disc 13 between the electrodes stops electrons not sufficiently deflected. The homogeneous beam produced may be modulated by causing it to pass through an apertured diaphragm and deflecting it in the ordinary way. Magnetic deflection may be substituted for electrostatic.