X-ray Plasma-source for Biological Applications

This article presents the plasma-source layout at the PLASMA-X laboratory and the results of the measurements of soft X-ray emission due to laser plasma source which uses different materials as target (mylar and yttrium). Plasma is obtained by focalizing Nd: YAG/Glass laser beam on target at λ = 532 nm. The pulse duration is tL = 6 nsec and the laser shot energy EL ranges from about 300 mJ and 4 J. The spectral X-ray emission is measured with a laser intensity of I ≈ 1012 - 1013 W/cm2. The conversion efficiencies of soft X-ray emission were measured in different energy ranges. One from 300 to 510 eV (almost coincident with the Water Window) and the other from 450 to 850 eV. The experimental data of conversion efficiencies are important in the realization of an intense monochromatic X-ray beam. In particular, the aim is to achieve a monochromatic microbeam to be used in radiobiological topics and in transmission X-ray microscopy.