Dynamic range measurements on streak image tubes with internal and external microchannel plate image amplification

Abstract

Electron–optic streak chronoscopy is an important diagnostic technique for the diagnosis of laser driven hydrodynamic and radiative phenomenon. To minimize the undesirable effects of excessive space charge in streak image tubes an image amplification stage is often used. Microchannel plate (MCP) electron amplifiers are frequently employed for this purpose. These devices may be utilized in two ways: either to amplify light from the streak image tube phosphor screen by externally coupling a proximity-focus MCP wafer intensifier tube, or by insertion inside the streak tube body to amplify the streaked electrons directly. To investigate how the operating regime of the MCP influences the dynamic range of the streak camera system, dynamic range measurements have been made on two identical streak image tubes (English Electric Valve Co. type P8307) one incorporating an internal MCP, the other, externally coupled image amplification. Dynamic range measurements have been made for 30 ps full width half maximum (FWHM) and 100 ps (FWHM) laser pulses and comparison made to a previous study of this type of image tube. For internal MCP and externally coupled intensifier camera systems of equal radiant gain the dynamic range for the pulse widths studied was found to be comparable.