Dr. Walker's scientific research focused on radiation from the Sun called extreme ultraviolet light and soft X-rays, which affect the chemistry of Earth's upper atmosphere, including the ozone layer.
X-ray microscopes usually operate with "soft" X-rays (wavelengths in the 1- to 10-nm range) and rely on reflective optics (see spectroscopy: X-ray optics) or "zone plates" (see optics: Filtering) to achieve focusing.
There is particular interest in soft X-rays with an energy of 100 1,000 electron volts, equivalent to a wavelength down to 1 nanometre (one- billionth of a metre), as opposed to about 500 nanometres for green light.
Even after the bulk of the material has merged with the local interstellar medium, there might be remaining regions of very hot gas that produce soft X-rays (i.e., those of a few hundred electron volts) observable locally.
Carbon-fibre could be scanned with "soft" X-rays, which are easier to generate and use.Scanning containers to look at their contents is, though, only one aspect of security.
So they use soft X-rays, which have a slightly longer wavelength than the kind used on a broken arm.
Modern micropattern gas counters are able to detect soft X-rays with high spatial resolution.
We consulted the GOES (NOAA 2014) catalogue of soft X-rays (SXR).
Compared to electrons soft X-rays have excellent tissue penetrating capability.
