Abstract:
Cesium dispenser with a metal carrier (for example, Al or Ag) in which silicon-alkali metal compounds or germanium-alkali metal compounds are present along the grain boundaries of the carrier material.
Abstract:
The present invention provides a photocathode which is formed on a substrate consisting of polycrystalline members, and which mainly consists of a semimetal, manganese or silver, and one or a plurality of alkaline metals, characterized in that the photocathode is formed on an alkaline metal oxide layer formed on the substrate, and a composition ratio of the semimetal, manganese or silver, and the one or a plurality of alkaline metals is stoichiometric or almost stoichiometric. The photocathode of the present invention has high sensitivity and can stably maintain the sensitivity for a long period of time.
Abstract:
According to the invention, under glancing incidence a first radiation (6) in the infrared range and which is linearly polarized is supplied to a target (2) made from a non-electrically insulating material and simultaneously to said target is supplied under a non-glancing incidence a second radiation (8) in the visible or ultraviolet range, in such a way that a same zone of the target is reached by the first and second radiations, the polarizing plane of the first radiation also being such that it contains a perpendicular to said zone, which then produces electrons.Application to the production of free electron lasers.
Abstract:
An infrared detector includes a vacuum tube containing a photo sensitive layer comprised of densely packed needles arranged vertically on a substrate and having been grown as metal whiskers in a porous portion of the substrate. The substrate includes a metallic layer either in contact with or insulated from the needles depending upon the mode of the detecting system. The needles may face the incoming radiation, or may face away therefrom, in which case at least part of the substrate has to be transparent to infrared radiation. The radiation is either acquired directly or through an infrared optic or through a raster or line-scanning system. Photo emission from the needles can be used either directly for the production of an image or indirectly through a scanning process. The diameter and distance of the needles is significantly smaller than the radiation band to be detected.
Abstract:
A photoemitter of improved quantum efficiency is formed by smoke or low density deposition of photoemissive materials on a substrate. Significantly, the photoemissive layer is deposited in the presence of a low pressure gas to form a layer whose density is not greater than 20% and preferably not greater than 5% of the photoemissive material in its bulk form. Individual particle size is controlled and deposited particles are isolated, affording greater surface contact area with the subsequently deposited constituent materials of the photoemissive surface, thereby enhancing interaction and increasing the photoelectron emission. The low density, randomly oriented smoke deposits provide a photosensitive surface characterized by high absorption, low reflective losses, and low transmissive losses. The spectral response curve of smoke photoemitters peaks further into the red or near infrared region than prior art devices, rendering the smoke photoemitters of the invention ideally suited for use as near infrared sensors in low light level imaging system.
Abstract:
A high efficiency tunnel electron emitter in which a unique emitting layer is applied to the insulator layer of a metalinsulator-emitting layer structure. The emitting layer consists of a low work function material such as cesium that is deposited directly on the insulator layer, a thin layer of a conductive metal that is deposited onto the cesium, and an exposed surface of the conductive metal having a layer of cesium oxide applied thereto to lower the work function. The amount of cesium deposited on the insulator layer is critical and is monitored for the proper amount during deposit.