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Absolute energy distribution of hard x rays produced in the interaction of a kilohertz femtosecond laser with tantalum targets Rev. Sci. Instrum. 77, 093302 (2006); 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 ϳ10 18 W/cm 2 onto a 5-m-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 10 14 to 10 15 W/cm 2 . Interferometric measurement indicates that the preformed-plasma expansion at the front surface is smaller than 15 m, 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.

Microstructure surface texture is studied with the Scanning Tunneling Microscope operated at atmospheric air pressure. A standardization procedure for surface microstructure is proposed. We introduce two parameters in order to characterize surface areas in the micrometre and submicrometre range, which we term "granular roughness" and "microroughness". Measurements of a class "0" standard block gauge give a granular roughness R, value of 0.02 pm.

With detailed experimental studies and hydrodynamics and particle-in-cell simulations we investigate the role of the prepulse in laser proton acceleration. The prepulse or pedestal (amplified spontaneous emission) can completely evaporate the irradiated region of a sufficiently thin foil; therefore, the main part of the laser pulse interacts with an underdense plasma. The multiparametric particle-in-cell simulations demonstrate that the main pulse generates the quasistatic magnetic field, which in its turn produces the long-lived charge separation electrostatic field, accelerating the ions.

three neutrino masses along with distinction of the mass hierarchy pattern (normal or inverted) by measuring the spectral shape I(ω). If one uses a target of available energy of a fraction of 1 eV, the most experimentally challenging observable, the Majorana CP phases, may be determined, comparing detected rate with differences of theoretical expectations which exist at the level of several %. The Majorana CP violating phase is expected crucial to the understanding of the matter-antimatter imbalance of our universe. Our master equation, when applied to E1×E1 transition such as pH 2 vibrational Xv = 1 → 0, can describe explosive PSR events in which most of the energy stored in |e is released in duration of order a few nano seconds.The present paper is intended to be self-contained explaining some details of related theoretical works in the past, and further reports new simulations and our ongoing experimental efforts of the project to realize the neutrino mass spectroscopy using atoms/molecules.

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A study of proton emission from a 3-μm-thick Ta foil target irradiated by p-, s-, and circularly polarized laser pulses with respect to the target plane has been carried out. Protons with energies up to 880keV were observed in the target normal direction under the irradiation by the p-polarized laser pulse, which yielded the highest efficiency for proton emission. In contrast, s- and circularly polarized laser pulses gave the maximum energies of 610 and 680keV, respectively. The difference in the maximum energy between the p- and s-polarized cases was associated with the difference between the sheath fields estimated from electron spectra.