Search

The time-lapse observation of the electrodeposition of copper in copper sulfate solution was performed by imaging X-ray fluorescence from the copper deposition. The X-ray fluorescence was directly imaged with a full-field Wolter mirror microscope, which was constructed at the Photon Factory. Controlling the electric current in the solution from 0 to 71.7 µA, the deposition of copper on a Pt cathode was directly observed by imaging its X-ray fluorescence. One exposure time for obtaining an X-ray fluorescence image was 80 s. Then, it was 17 min later from the beginning of the electrolysis when the X-ray fluorescence image of the electrodeposition is observed for the first time. At this exposure time, the detection limit of the mass of copper was estimated to be 0.60 pg/image, which was calculated using test samples of 1.00×10-3–1.00 mol/l copper sulfate solutions.

A low-density solid xenon (Xe) target has been developed as laser-produced plasma (LPP) extreme ultraviolet (EUV) source. Xe gas was cooled to below the condensation temperature, and liquid Xe was sprayed from a swirl atomizer into a low-pressure atmosphere. Microparticles of liquid Xe were rapidly cooled by their own latent heat of evaporation, and became a solid micrometer-sized powder. The most frequent particle diameter under an atomizing pressure of 0.3 MPa was 114 µm, and the apparent density was 0.2 g/cm3, 1/13 of the density of conventional solid Xe. The apparent production rate of the powder was 2.2 cm3/s.

The effect of the initial density of xenon (Xe) targets on extreme ultraviolet (EUV) emission has been investigated. With decreasing initial density, it was found that the spectral width around 11 nm becomes broad, and the intensity of 13.5 nm emission increases. The maximum conversion efficiency (CE) for solid Xe targets is approximately 0.6% at a 2×1011 W/cm2 of laser intensity, whereas that for the low-density targets is approximately 0.7% at a 4×1011 W/cm2. The spectral broadening with decreasing initial density can be attributed to the change in optical thickness of laser-produced plasmas. The enhancement of CE is attributed to optically thick plasma formation.

An ultraviolet (UV) short-pulse intensity diagnostic method using atmosphere as a nonlinear medium was developed. This diagnostic method is based on evaluating the ion charge of the two-photon ionization of atmospheric oxygen upon irradiation with a UV (238–299 nm) short-pulse laser. The observed ion signal increased proportionally to the input intensity to the power of ∼2.2, during the two-photon ionization of atmospheric oxygen. An autocorrelator was constructed and used to successfully measure a UV laser pulse of ∼400 fs duration. Since this diagnostic system is used in the open-air under windowless conditions, it can be set along the beam path and used as a UV intensity monitor.