Abstract: A so-called "solar-blind" photomultiplier tube includes an envelope having a sidewall and an input faceplate formed from an ultraviolet transmitting filter. A photoemissive cathode is disposed within the envelope for providing photoelectrons in response to radiation incident thereon. The cathode has an intrinsic responsivity extending from the near-ultraviolet portion through the visible portion of the electromagnetic spectrum; however, the filter faceplate transmits only the ultraviolet portion of the spectrum to the photoemissive cathode. The combination of the filter faceplate and the photoemissive cathode therefore limits the tube to a responsivity within the wavelength range of about 300 to less than 400 nanometers.

Abstract: The photomultiplier tube comprises an evacuated envelope having therein a photocathode, an anode, a plurality of spaced apart dynodes for propagating and concatenating electron emission from the photocathode to the anode and a pair of substantially parallel support spacers of insulating material to support the dynodes and the anode. A chrome oxide layer is disposed on the support spacers adjacent to the dynodes and the anode. The chrome oxide layer has a resistance of at least about 10.sup.12 ohms per square to about 10.sup.15 ohms per square. A Nichrome coating overlies an inter-electrode region extending along the concatenating path of the electron emission from the dynodes to the anode. The Nichrome coating has a resistance of greater than 10.sup.6 ohms per square but less than the resistance of the chrome oxide layer.

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: 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 electron tube having an evacuated envelope includes therein an insulating substrate with a photoemissive cathode thereon. The cathode comprises a plurality of discrete substantially isolated photoemissive regions. A plurality of spaced apart conductive strips are disposed on the substrate and interconnect each of the photoemissive regions.

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: A method is described for stabilizing the anode sensitivity of a photomultiplier tube having a photocathode, an anode, and a plurality of dynodes including at least one Nichrome dynode adjacent to the anode. The steps include differentially heating the tube so that the temperature of the Nichrome dynodes and the anode is substantially greater than the photocathode. The temperature gradient established by the differential heating redistributes alkali material from the surface of the dynodes in a beneficial manner so as to balance the secondary emission gain of the dynodes so that decrease in Nichrome dynode gain is offset by increases in the gain of the other dynodes. The tube is then bright aged at a first voltage followed by a dark age at a higher voltage. The aging steps rearrange or rebind the remaining loosely bound alkali material to provide an increase in anode sensitivity stability.

Abstract: A base layer comprised of antimony and oxygen is formed on a substrate within an evacuated enclosure. Rubidium, potassium and cesium are then evaporated onto the base layer after which the substrate is heated to promote an activating reaction between the rubidium, potassium, cesium and antimony.

Abstract: A film of either manganese or antimony is evaporated onto a substrate within an evacuated enclosure. Oxygen is introduced into the enclosure to oxidize the film. A layer of antimony is then deposited onto the oxidized film to a predetermined thickness measured by the transmission of light through the substrate. Rubidium and cesium are then evaporated onto the antimony layer after which the substrate is heated to promote an activating reaction between the rubidium, cesium and antimony. Photocathodes formed in this manner, without superficial oxidation, typically have sensitivities within the range of 80-130 microamperes per lumen.

Abstract: A method is provided for making a photocathode including the step of forming a base layer including antimony on a substrate. Sodium is then evaporated at an elevated temperature onto the base layer such that the sensitivity increases to a value which is less than a peak value. At an intermediate temperature potassium is evaporated to a first peak value of sensitivity. Antimony and potassium are alternately evaporated until a second peak value of sensitivity is achieved. At the above-mentioned intermediate temperature, cesium is evaporated to a third peak value of sensitivity. Antimony and cesium are alternately evaporated until a fourth peak value of sensitivity is attained. The photocathode is slow cooled from the intermediate temperature to a second intermediate temperature at which point the cooling rate is increased in order to permit the photocathode to reach room temperature.

Abstract: A photocathode is formed by depositing a film of tellurium on a conductive base and then sensitizing the tellurium with at least two different alkali metals such as cesium and potassium or sodium and potassium. The photocathode has high sensitivity in the ultraviolet region and is substantially insensitive to solar radiation through the earth's atmosphere. Such a photocathode is useful in "solar-blind" detectors.

Abstract: In a photomultiplier tube, antimony layers of a photocathode are prepared on a nickel substrate by providing a barrier layer of aluminum oxide between the substrate and antimony layers. The photocathode is subsequently exposed to the vapors of at least one alkali metal to sensitize the antimony layers. The aluminum oxide layer prevents alloying of the nickel with the antimony at processing temperatures in the range from 260.degree. C. to 285.degree. C. and provides a source of oxygen to oxidize the photocathode for increased photosensitivity, the oxidation time being a function of the thickness of the aluminum oxide layer. The photocathode is then exposed to cesium and may be superficially oxidized until substantially maximum photosensitivity is achieved.