X-ray grating spectrometer for opacity measurements in the 50 eV to 250 eV spectral range at the LULI 2000 laser facility.

An x-ray grating spectrometer was built in order to measure opacities in the 50 eV to 250 eV spectral range with an average spectral resolution ∼ 50. It has been used at the LULI-2000 laser facility at École Polytechnique (France) to measure the Δn = 0, n = 3 transitions of several elements with neighboring atomic number: Cr, Fe, Ni, and Cu in the same experimental conditions. Hence a spectrometer with a wide spectral range is required. This spectrometer features one line of sight looking through a heated sample at backlighter emission. It is outfitted with one toroidal condensing mirror and several flat mirrors cutting off higher energy photons. The spectral dispersion is obtained with a flatfield grating. Detection consists of a streak camera sensitive to soft x-ray radiation. Some experimental results showing the performance of this spectrometer are presented.

X-ray diagnostic calibration with the tabletop laser facility EQUINOX.

The broadband x-ray emission of a target irradiated by a laser can be used to check the calibration of detectors. At CEA-DIF we have a tabletop picosecond laser facility called EQUINOX with 0.3 J at 800 nm. The laser is focused inside a target chamber onto a solid target and produces bright radiation in the 100-2000 eV spectral range. The x-ray source is routinely monitored with a pinhole camera for source dimension measurement and with x-ray diodes for flux measurement. In addition an x-ray transmission grating spectrometer, a crystal spectrometer, and a single count charge coupled device camera measure the x-ray spectrum between 100 eV and 15 keV. The absolute calibration of those sets of spectrometers allows us to fully characterize x-ray emission spectra. Typical duration is less than 100 ps. The spectrum can be tuned by changing target material, pulse length, and x-ray filters. An application to checking the calibration of x-ray diodes used in the broad band spectrometer DMX with single shots will be presented.