A simple high-resolution on-line x-ray imaging crystal spectrograph for laser–plasma interaction studies

Abstract

A simple, high-resolution x-ray imaging crystal spectrograph is described for on-line measurements and analysis of x-ray emission from laser-produced plasmas in the wavelength range of ∼5–12 Å. The spectrograph uses a planar TAP crystal for dispersion and a phosphor-coated optical fiber plate followed by an image intensifier and a charge-coupled device camera for detection. The spectrograph covers a wavelength range of ∼1.4 Å in a single shot about a desired wavelength setting with a spectral resolution of ∼0.012 Å. It also has a design flexibility to cover the full spectral range of 5–12 Å in a single shot with a spectral resolution of ∼0.040 Å. The spectrograph is particularly suited for studies involving low vacuum environment, e.g., plasma interaction with a background gas, laser interaction with a gas jet, etc., which preclude the use of other on-line detectors such as open-ended microchannel plates. An example of space resolved x-ray emission from laser-produced magnesium plasma expanding in a helium gas is also presented.