poplar_yang
第3楼2010/12/02
the more energetic X-rays (E > 30 keV) can penetrate the air for distances of at least a few meters;
By contrast, soft X-rays can hardly be said to penetrate matter at all; for instance, the attenuation length of 600 eV (~ 2 nm) x-rays in water is less than 1 micrometer.
X-rays with an energy of 22.1 keV, how far do these penetrate a piece of pure iron, (atomic number 26)? =0.07 mm