Flash X-ray microscopy with a gas jet plasma source.

A novel flash X-ray source, the gas jet plasma source, has been used for contact X-ray microscopy. Using a wavelength range of 2-7 nm a resolution of the order of 30 nm can be obtained. The gas jet plasma source provides a new and unique tool which should allow future imaging of wet live cells.

Evaluation of high efficiency Csl and Cul photocathodes for soft x-ray diagnostics.

The photoefficiency of CsI and CuI photocathodes was measured for photons in the 22-240-eV (50-560-A) energy range. The within-batch and batch-to-batch variation in photoefficiency were studied as was the sensitivity of the samples to storage under dry nitrogen. The effect of exposure to air was investigated. The shape of the photoefficiency curves was found to agree quite well with that expected from the photoabsorption cross sections of the materials. CsI in particular appears useful as a detector in soft x-ray diagnostics, especially as a narrowband detector in the 100-eV photon energy range where peak measured efficiencies can exceed 300%.

Sub-keV x-ray imaging using a low-cost ellipsoidal lens.

An ellipsoidal lens has been evaluated using the sub-keV x radiation from a laser-produced plasma. The measured collection efficiency is ~0.3%. Inexpensive fabrication and alignment techniques are discussed, and imaging measurements using visible and x-ray sources are presented.

Closure of pinholes under intense laser radiation.

The closure of pinholes due to plasma created by intense laser radiation interacting with the pinhole perimeter is studied. Pinholes with 100-300-microm initial diam close in 3-14 nsec, respectively, for a 10-nsec FWHA, 10-J incident laser pulse. For a constant focal spot size and pulse duration, the closure time and rate are found to be a function of laser energy; however, the energy transmitted through the pinhole is independent of the incident energy for the pulse duration, pinhole diameters, and focal spot size used in these experiments.