Rca Inc.

Arthur F McDonie

Richard D Faulkner

Charles M Tomasetti

Donald B Kaiser

Ralph Warren Engstrom

Fred A Helvy

Maurice D Harsh

William K Miller

Daniel L Thoman

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.

Electron discharge device having a narrow range spectral response

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.

Photomultiplier tube having a high resistance dynode support spacer

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. A locating portion extends from the other end of the slot engaging portion along the other oppositely disposed surface of the plate and through one of the locating slots formed in the shield cup. The attachment portion of the tab member is fixedly attached to the shield cup.

Shield cup to cage assembly connecting tab member for photomultiplier

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. The light shield has a transverse dimension substantially equal to that of the flaps to establish a minimum transverse spacing between the distal end of the support plates. The flaps and the light shield thus act, in combination, to provide a uniform minimum transverse spacing between the support plates which is greater than the transverse dimension of the anode and the dynodes to prevent distortion of the field mesh. The tab ends of the dynode and the anode are bifurcated so that one portion of selected ones of the tab ends can be formed to secure the dynodes and the anode between the support plates.

Photomultiplier tube having an electron multiplier cage assembly with

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.

Photoemissive cathode formed on conductive strips

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.

Photomultiplier tube having improved count-rate stability

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.

Method for stabilizing the anode sensitivity of a photomultiplier tube

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.

Method of making potassium, cesium, rubidium, antimony photocathode

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.

Rubidium-cesium-antimony photocathode

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.

Method for expeditiously processing a sodium-potassium-cesium-antimony

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.

Bi-alkali telluride photocathode

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.

Red sensitive photocathode having an aluminum oxide barrier layer

A reflective type photocathode of a photomultiplier includes a porous antimony layer in overlay relation to a layer of solid antimony along a supporting substrate.

Electron emitter including porous antimony

In a photomultiplier tube, antimony layers of a photocathode and a plurality of dynodes are simultaneously sensitized by exposure to the vapors of sodium and potassium at an initial temperature of less than about 120.degree. C. The temperature of exposure is gradually increased at a rate of less than about 10.degree. C. per minute until a final temperature of about 200.degree. C. is reached. Then, the photocathode and dynodes are baked at the final temperature until substantially maximum photosensitivity is achieved. The photocathode and dynodes are thereafter exposed to cesium and may be superficially oxidized until substantially maximum photosensitivity is achieved.

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Lancaster, PA, United States of America

Arthur F McDonie