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Presents a study which examined the x-ray emission in the water window spectral region from materials irradiated by a slab glass laser. Suitability of carbon as a source material for an x-ray microscopy experiment; Derivation of the electron density and electron temperature of the carbon plasmas; Results of the experiment.

We observe UV harmonics and protons with a 7.5-nm-thick polyimide target irradiated with a high-intensity Ti:sapphire laser. The laser intensity dependence of UV harmonics and proton signal is measured by varying the distance between the target surface and the best focus of the laser beam. In the case of appropriate condition for proton generation with a maximum energy of ~2.7 MeV, the weak broad spectrum in the UV region is generated. The UV harmonics of up to the fourth order are generated as the target is moved away from the best focus position. In this condition, the maximum energy of protons is reduced to ~1 MeV. The simultaneous generation of the harmonics and pro- tons is observed at the amplified spontaneous emission intensities between ~5 × 1011 and ~5 × 1012 W/cm². [ABSTRACT FROM AUTHOR]

Fast protons are observed by a newly developed online time-of-flight spectrometer, which provides shot-to-shot proton-energy distributions immediately after the irradiation of a laser pulse having an intensity of ∼1018 W/cm2 onto a 5-μm-thick copper foil. The maximum proton energy is found to increase when the intensity of a fs prepulse arriving 9 ns before the main pulse increases from 1014 to 1015 W/cm2. Interferometric measurement indicates that the preformed-plasma expansion at the front surface is smaller than 15 μm, which corresponds to the spatial resolution of the diagnostics. This sharp gradient of the plasma has the beneficial effect of increasing the absorption efficiency of the main-pulse energy, resulting in the increase in the proton energy. This is supported by the result that the x-ray intensity from the laser plasma clearly increases with the prepulse intensity. [ABSTRACT FROM AUTHOR]

Proton acceleration experiments involving a 5 μm thick Ti foil target irradiation are carried out with the femtosecond Ti:sapphire laser JLITE-X. The plasma emission at 13.5 nm is recorded employing concave multilayer mirrors, which image the front- and rear-side plasmas onto the sensitive surfaces of a fast x-ray photodiode and a backside-illuminated charge coupled device. Online time-of-flight fast-particle measurements are performed simultaneously with the extreme ultraviolet (XUV) measurements. A strong correlation is observed between the energetic proton signal and the spatiotemporal behavior of the XUV plasma emission. In particular, the longer duration of the prepulse-produced XUV plasma emission indicates a lowering of the maximum proton energy. This allows using the XUV emission for the diagnostics of the high-intensity laser–solid-target interaction. [ABSTRACT FROM AUTHOR]

We demonstrate for the first time the production of more than 108 neutrons per shot from a carbon-deuterium plasma confined in a 100-μm-thick gold shell without an implosion using six beams from a GEKKO XII glass laser system at a laser wavelength of 1.06 μm. The equivalent neutron of the deuterium-tritium reaction is estimated to be 1010–1011. [ABSTRACT FROM AUTHOR]