Laser plasma source for XUV calibration

摘要

We present a calibration system for X-UV (40 - 400 angstroms) instrumentation used in inertial confinement research. A small pulsed laser, 4 Joules, 4 nanoseconds in the green (0.54 mm wavelength), is focused onto solid targets of different materials such as aluminum or gold with a repetition rate of one every 30 seconds. The radiation given by the plasmas produced on these targets is selected by a monochromator made with a grazing incidence grating associated with a toroidal mirror. The grating is planar and its period per mm is slightly variable in order to record the spectra in a plane when working as a spectrograph. The selected radiation from the monochromator enters a vacuum vessel, in the center of which is put a goniometer $theta@/2$theta@. This goniometer measures the reflectivity of multilayer mirrors, using XRD diodes absolutely calibrated. The system measures the response of photocathodes of streak cameras working in the X-UV range and other photon detectors in the same range.