Transmission Secondary Emission Research Articles

Secondary Emission of Thin Self-Supported Films of MgO

This article contains experimental reflection and transmission secondary emission yield curves obtained from a 475 Å unbacked MgO film. The film has a transmission yield maximum of 2.6 at a primary energy of 3 kev. An analysis, employing experimental transmission retarding potential characteristics also obtained in this study, proves a lack of proportionality between the production of secondaries and the energy dissipated by the primary beam in MgO. The extreme range of a 3600-ev primary in MgO is found to be 475 Å.

The Transmission Secondary Emission Image Intensifier and Its Application to Low Light Level Imaging

An image intensifier utilizing transmission secondary electron emission has been described elsewhere. Performance data on recent 4-stage tubes having 1 inch useful diameter is given. At low light levels, viewing with these tubes is photoelectron-noise-limited. These tubes resolve a minimum of 12 line pairs/mm or a total of 300 line pairs across a diameter. Photon gains as high as 20,000 have been measured. Application of this intensifier to nuclear track photography is described.

Image Intensification by Transmission Secondary Electron Emission

The successful operation of a multistage image intensifier using a series of aluminum dynodes coated with thin layers of BaF/sub 2/ and reinforced with very fine wide-mesh grid ia reported. The electron gain in the best of these tubes is 2400, corresponding to sn average secondary emission ratio of 7 per dynode. The photon gsin with 15kw acceleration from the last dynode to a P11 output phosphor is about 10,000. At low light levels, resolution is limited by photoelectron noise. This tube, when fully developed, will be well suited to the amplification of extremely low light level images such as those encountered in astronomy, nuclear particle track photography, spectroscopy, and x-ray fluoroscopy. (D.L.C.)

Some Observations on Transmission Secondary Emission

Some Observations on Transmission Secondary Emission

Transmission Secondary Electron Multiplication for High-Speed Pulse Counting

A new type of high-speed electron multiplier employing transmission secondary electron emission from thin insulating films is described. Electrons from a photosurface are multiplied in a series of plane-parallel dynodes consisting of a thin scattering layer of a heavy metal followed by a layer of a pure crystalline insulating material of high secondary emission yield. The characteristics of such dynodes are described, and the dc and pulse performance of an experimental seven-stage device employing this principle is presented.

High-Speed Electron Multiplication by Transmission Secondary Electron Emission

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