High-resolution X-ray spectrometer based on spherically bent crystals for investigations of femtosecond laser plasmas

Ultrashort-pulse, laser-produced plasmas have become very interesting labor atory sources to study spectroscopically due to their very high densities a nd temperatures, and the high laser-induced electromagnetic fields present. Typically, these plasmas are of very small volume and very low emissivity. Thus, studying these near point source plasmas requires advanced experimen tal techniques. We present a new spectrometer design called the focusing sp ectrometer with spatial resolution (FSSR-2D) based on a spherically bent cr ystal which provides simultaneous high spectral (lambda/Delta lambda approx imate to 10(4)) and spatial resolution (approximate to 10 mu m) as well as high luminosity (high collection efficiency). We described in detail the FS SR-2D case in which a small, near point source plasma is investigated. An e stimate for the spectral and spatial resolution for the spectrometer is out lined based on geometric considerations. Using the FSSR-2D instrument, expe rimental data measured from both a 100 fs and a nanosecond pulse laser-prod uced plasma are presented. (C) 1998 American Institute of Physics. [S0034-6 748(98)00712-6].