High-sensitivity, portable, tunable imaging X-ray spectrometer based on a spherical crystal and MCP

A portable (200×100×100 mm3), high-luminosity, spherically bent crystal spectrometer was designed to measure very low emissivity X-ray spectra of different elements with spatial resolution in a wide spectral range (1.2−19.6 Å). A large (50×15 mm2) open aperture mica spherically bent crystal with R=150 mm was used as dispersive and focusing element. This spectrometer was associated with a large sensitive area (φ=40 mm) micro-channel plates assembly. This apparatus provides simultaneously high spectral (λ/δλ∼1800) and spatial (100–200 μm) resolutions. Its large tunability allowed, without any adjustment of the spectrometer set-up, to record spectra in the 1.38–17.5 Å wavelength range. We used the X-ray emission of femtosecond laser-produced plasmas from different materials ((CF2)n, CaF2, Cu, Al) to test the spectrometer. Thanks to the high sensitivity (high collection efficiency) of the system, high quality space-resolved X-ray spectra of Fluorine and Aluminum plasmas were obtained on a single laser shot.