Abstract: Electron multiplier plate with controlled multiplication, multiplier element comprising the said plate, multiplier device comprising the said element and application of the said device to a photomultiplier tube.Secondary emission electron multiplier plate (10) of the "aperture plate" type, comprising multiplier apertures (11), each having an input side (12), an output side (13), and an efficacious multiplier partition (14) having emissive power. Multiplier plate (10) has at least one elementary multiplier pattern (15) comprising a plurality of multiplier apertures, at least the said efficacious multiplier partitions (14a) of the peripheral multiplier apertures (11a) of the pattern (15) being oriented towards the interior of the said pattern.

Abstract: The electron multiplier is of the kind in which a charge current is amplified by successive passage to and secondary emission of electrons from dynodes which are arranged in two opposed rows. The multiplier is arranged for application of electric charge to the dynodes so as to focus the charge current on to each of the dynodes in succession, alternating between the rows. The dynodes have electron emissive surfaces to which the charge current passes and angled flanges located at opposite edges of the surfaces. The surfaces are preferably formed by aluminum foil. The rows of dynodes are preferably formed by aluminum foil. The rows of dynodes are supported on opposed cantilevered insulating members by crimped straps.

Abstract: A photomultiplier control circuit includes a circuit for receiving an output signal of a photomultiplier, which detects a light to be measured and converts the detected light to an electric signal in order to generate an output depending on a level of the light to be measured. A light source is used for applying a compensating light to the photomultiplier and a circuit is provided for detecting an average anode current of the photomultiplier. A comparison circuit compares outputs of both circuits and generates the resulting difference output. A control circuit controls the intensity of a light emitted from the light source based on the difference output. The circuit is capable of stabilizing gain fluctuations of a photomultiplier when the incident light is input thereto in the form of a direct current, and also capable of maintaining the accuracy of a photomultiplier when it is employed in measuring tools, etc.

Abstract: A light detector which can be gated on and off over an ultrashort time window, such as in picoseconds or femtoseconds, is disclosed. The light detector includes, in one embodiment, an input slit for receiving a light signal, relay optics, a sweep generator and a tubular housing, the tubular housing having therein a photocathode, an accelerating mesh, a pair of sweeping electrodes, a microchannel plate, a variable aperture and a dynode chain. Light received at the input slit is imaged by the relay optics onto the photocathode. Electrons emitted by the photocathode are conducted by the accelerating mesh to the sweeping electrodes where they are swept transversely across the tubular housing at a rate defined by the sweep generator over an angular distance defined by the sweeping electrodes, in a similar manner as in a streak camera. Swept electrons strike the microchannel plate where electron multiplication is accomplished.

Abstract: An electron discharge device, such as a photomultiplier tube, has an evacuated envelope with an alkali-antimonide photoemissive cathode therein. A thermionic emission-reduction coating is disposed within the envelope. The coating alloys with the constituents of the photoemissive cathode to reduce thermionic emission. The thermionic emission reduction coating is formed preferably of indium; however, indium oxide may also be used.

Abstract: A photomultiplier tube comprises an evacuated envelope having a photoemissive cathode, a shield cup spaced from the cathode and an electron multiplier cage assembly abutting the shield cup. The cage assembly includes a pair of transversely spaced insulating support plates having oppositely disposed surfaces. A plurality of dynodes and an anode are disposed between the support plates. A plurality of oppositely disposed locating slots are formed in the shield cup. At least one tab slot is formed through the oppositely disposed surfaces of each of the support plates. A plurality of connecting tab members are provided for connecting the cage assembly to the shield cup. Each tab member includes a slot engaging portion, a locking portion, a locating portion and an attachment portion. The slot engaging portion is disposed within the tab slot of the support plate. The locking portion extends from one end of the slot engaging portion for securely engaging one surface of the plate.

Abstract: An improved electron discharge device comprises an evacuated envelope having therein a photoemissive cathode for providing photoelectrons in response to radiation incident thereon, an electron multiplier, including a primary dynode spaced from the cathode, and a focusing assembly disposed between the cathode and the multiplier. A thermionic electron control plate is disposed between the focusing assembly and the multiplier to prevent thermionic electrons from the focusing assembly from impinging on the primary dynode, while permitting the passage of photoelectrons to the primary dynode. The control plate overlies the primary dynode and is contiguous therewith.

Abstract: A photomultiplier tube comprises an evacuated envelope having a photoemissive cathode, a shield cup spaced from the cathode and an electron multiplier cage assembly abutting the shield cup. The cage assembly includes a pair of transversely spaced support plates having a plurality of support slots formed therethrough. The support plates are attached to the shield cup. A plurality of electrodes are disposed between the support plates. At least one of the electrodes has reference apertures therein and a mesh member attached thereto which has locating slots aligned with the reference apertures. The electrodes have an active portion and attachment tabs which are disposed within the support slots in the support plates to support the electrodes therebetween. The electrodes also have support shoulders formed in opposite sides thereof between the active portion and the attachment tabs.

Abstract: A photomultiplier tube comprises an evacuated envelope including a faceplate and a sidewall. A conductive coating is disposed annularly around an interior portion of the sidewall adjacent to the faceplate and on a longitudinally extending portion of the sidewall as a strip. A photoemissive cathode is disposed on an interior surface of the faceplate and on the conductive coating adjacent thereto. A shield cup is spaced from the cathode and centered within the envelope by a plurality of bulb spacers. An electron multiplier cage assembly abuts the shield cup and is attached thereto. A cathode contact assembly is in contact with the strip on the sidewall. A plurality of locating slots are formed in the base of the shield cup to orient the bulb spacers in contact with the sidewall of the envelope and spaced from the longitudinally extending strip portion of the conductive coating thereon. The bulb spacers include stop shoulders which retain the bulb spacers within the locating slots.

Abstract: A photomultiplier tube comprises an evacuated envelope having a photoemissive cathode, a shield cup spaced from the cathode and an electron multiplier cage assembly abutting the shield cup. The cage assembly includes a pair of transversely spaced support plates having a plurality of support slots formed therethrough. Each of the support plates has a distal end and a proximal end, with the proximal ends being attached to the shield cup. A light shield is disposed between the distal end of the support plates. An anode and a plurality of dynodes, at least one of which has a field mesh attached thereto, are disposed between the support plates and attached thereto by end tabs. The end tabs extend from the side of the anode and the dynodes. The aforementioned shield cup includes flaps which establish a minimum transverse spacing between the proximal ends of the support plates.

Abstract: An improved electron discharge device comprises an evacuated envelope having at least one alumina ceramic insulator member. Within the device is a source of electrons, and an electron multiplier assembly including an anode. A high resistance material is diffused into the ceramic insulator to reduce luminescence within the insulator. The method of diffusion includes the steps of applying an opaque coating of a high resistance material to a surface of the ceramic insulator member and then firing the member in a reducing atmosphere at a temperature within the range of about 1500.degree. C. to 1550.degree. C. until the high resistance material diffuses into the surface of the member forming a diffusion region.

Abstract: A photomultiplier tube includes an evacuated envelope having therein a photocathode, an anode and an electron multiplier disposed between the cathode and the anode for propagating and concatenating electrons along a path therebetween. The electron multiplier and the anode are supported by a pair of oppositely-disposed support plates. At least one aperture which extends along at least a portion of the electron path is formed in each plate. A pair of focusing shields may be spaced from the exterior surface of each of the support plates. The focusing shields are disposed adjacent to the apertures in the support plates and extend longitudinally along the electron path to provide a transverse focusing field which prevents substantially all of the electrons from impinging on the interior surface of the support plates.

Abstract: An improved electron multiplier assembly includes a plurality of communicating electrodes affixed to a pair of insulative support plates. The electrodes comprise a plurality of dynodes including an ultimate dynode and an anode. The anode comprises a substantially flat, rigid member having at least one longitudinally-extending aperture. The anode is disposed substantially within and spaced from the ultimate dynode. Mounting tabs extend from the anode to inflexibly secure the anode to the support plates.

Abstract: A photomultiplier tube comprises an evacuated envelope having therein a photocathode, an anode and a high speed electron multiplier. The electron multiplier includes a primary dynode having a substantially parallel electron permeable member spaced from the primary dynode and disposed between the photocathode and the primary dynode. The electron permeable member also extends between the primary dynode and a plurality of secondary dynodes and accelerates secondary electrons from the primary dynode towards an input secondary dynode. Steering means disposed between the electron permeable member and the secondary dynodes direct the secondary electrons toward the input secondary dynode. Optional electron permeable second members, spaced from and disposed parallel to the secondary dynodes are operated at a potential midway between the adjacent dynode and the next succeeding dynode to accelerate the secondary electrons towards the anode.

Abstract: A photomultiplier tube comprises an electron multiplier assembly including a pair of oppositely-disposed insulative support spacers. A plurality of elements including an ultimate dynode and an anode are affixed to the support spacers. The ultimate dynode comprises a relatively inflexible multilateral hollow member having two plane-face surfaces lying at an acute angle to one another and terminating at a lower transverse edge. The ultimate dynode includes dynode mounting tabs extending from opposing ends thereof for affixing the ultimate dynode to the support spacers. The anode includes a substantially flat electron permeable mesh portion spaced from one of the plane-face surfaces of the ultimate dynode. Anode mounting tabs extend from opposing ends thereof for affixing the anode to the support spacers. Electrical leakage isolation slots are formed in the support spacers to increase the electrical leakage path length across the support spacers between the ultimate dynode and the anode.