
there's the antiprotonic helium ion, (which isn't depicted right there), but it's possible, and there are also helium ions used for microscopy ( en.wikipedia.org/wiki/Scanning_Helium_Ion_Microscope )
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Wed 21 Feb 2007, 23:58,
archived)

I am meant to be using SEM, that now adds another 500 words to my dissertation
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Thu 22 Feb 2007, 0:00,
archived)