English: Figure 6-3. ED50 for CTA as a function of LET for the following radiation sources: 40Ar = argon ions, 60Co = Cobalt-60 gamma rays, e- = electrons, 56FE = iron ions, 4He = helium ions, n0 = neutrons, 20Ne = neon ions (Rabin et al., 1991).
The NASA website hosts a large number of images from the Soviet/Russian space agency, and other non-American space agencies. These are not necessarily in the public domain.
The SOHO (ESA & NASA) joint project implies that all materials created by its probe are copyrighted and require permission for commercial non-educational use. [2]