Two of the key issues of a krypton fluoride (KrF) laser driver for inertial fusion energy are the development of long life, high transparency pressure foils (to isolate vacuum in the electron beam diode from a working gas in the laser chamber), and the development of durable, stable, optical windows. Both of these problems have been studied on the single-pulse e-beam-pumped KrF laser installation GARPUN. We have measured the transport of electron beams (300 keV, 50 kA, 100 ns, 10 × 100 cm) through aluminum-beryllium and titanium foils and compared them with Monte Carlo numerical calculations. It was shown that 50-μm thickness Al-Be and 20-μm Ti foils had equal transmittance. However, in contrast to Ti foil, whose surface was strongly etched by fluorine, no surface modification nor fatal damages were observed for Al-Be foils after ∼1000 laser shots and protracted fluorine exposure. We also measured the 8% reduction in the transmission of CaF2 windows under irradiation by scattered electrons when they were set at 8.5 cm apart from the e-beam-pumped region. However an applied magnetic field of ∼0.1 T significantly reduced electron scattering both across and along the laser cell at typical pumping conditions with 1.5 atm pressure working gas. Thus the e-beam-induced absorption of laser radiation in optical windows might be fully eliminated in an e-beam-pumping scheme with magnetic field guiding.

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φ mesons were reconstructed in the K + K − channel in Au-Au collisions at √ s NN = 200 GeV by the PHENIX experiment. φ invariant masses were reconstructed using a high resolution time-of-flight detector and electromagnetic calorimeters for particle identification, in conjunction with the excellent momentum resolution of the PHENIX tracking detectors. A description is given of the techniques for signal extraction and the corrections applied to obtain yields.