X pinch X-ray radiation above 8 keV for application to high-resolution radiography of biological specimens

The X pinch is a dense plasma X-ray source that is known to emit subnanosecond bursts of X-rays in the 2.5-8 keV energy range from a very small (/spl sim/1 /spl mu/m) source commonly referred to as a micropinch. As such, it has been successfully used as a point source for X-ray radiographic imaging of small biological samples with spatial resolution as good as 1-2 /spl mu/m. Recent experiments show that the soft X-ray emission from a micropinch extends out to as high as 15 keV, and that there is also harder radiation from a slightly displaced /spl sim/100 /spl mu/m source with photon energies reaching above 60 keV that appears to be due to the presence of several-nanosecond electron-beam pulse. Both of these harder X-ray sources are potentially useful X-ray sources for high-resolution radiography of thicker biological samples than we have previously imaged. A characterization of these two hard X-ray radiation sources from X pinch plasmas using a slit camera with different filters, as well as imaging of a variety of biological objects on each pulse, revealed the energy range and source size of the micropinch radiation separate from the larger electron-beam source. High-resolution images (1-10 /spl mu/m scale resolution) of samples, such as a boron fiber with tungsten core (2.5-12 keV) as well as a several-millimeter-thick chicken wing with bone (>10 keV), will be presented.