A pulsed soft x-ray source for use in contact microscopy would provide high-resolution, high-contrast images with minimal radiation damage to the biological specimen involved. An x-ray plasma source offers some advantages over synchrotron radiation in terms of smaller physical size, lower cost, larger beam size, and higher flux per pulse. The operation of a pulsed plasma focus device is described and this system is compared to other plasma sources. Results of a radiation model calculation predict that the use of neon gas would produce 1.2- to 1.4-nm radiation in 50- to 100-J pulses (emitted into 47 sterradians) with an efficiency of 1%. The actual source is about 2 mm in diameter and the x-ray pulse lasts about 15 to 20 ns. By choosing the proper gas or electrode material, one can generate a combination of emission lines that cover the region between the carbon edge (300 eV) to 2 keV. The system operates in the pressure range of a few torr. With the x-ray resists being developed for submicron x-ray lithography, microradiographs can be produced that have resolutions of 0.1 pm. The intense pulsed output can provide enough flux to make possible the micrography of wet or alive specimens.
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