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We report the demonstrated irradiation effect of laser-accelerated protons on human cancer cells. In vitro (living) A549 cells are irradiated with quasimonoenergetic proton bunches of 0.8–2.4 MeV with a single bunch duration of 15 ns. Irradiation with the proton dose of 20 Gy results in a distinct formation of γ-H2AX foci as an indicator of DNA double-strand breaks generated in the cancer cells. This is a pioneering result that points to future investigations of the radiobiological effects of laser-driven ion beams. Unique high-current and short-bunch features make laser-driven proton bunches an excitation source for time-resolved determination of radical yields. [ABSTRACT FROM AUTHOR]

We have investigated a chloromethylated calixarene, p-chloromethylmethoxcalix[n]arene (CMC[n]AOMe) (n=5,6,7), as a negative resist in electron-beam lithography. Each CMC[n]AOMe resist has a resolution of about 12 nm and a sensitivity of about 0.8 mC/cm[sup 2] which varies slightly with n (or molecular weight). A sub-10-nm Si wire has been fabricated by halide plasma etching and a CMC[n]AOMe resist as an etching mask. Because the resist pattern edge is smooth, Si wires with 7-nm width and 10-μm length were performed without any breaking. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]