P.M.S. Blackett
n.d.
Experiments by Blackett in a Wilson Cloud Chamber.

Photographic illustrations
Wellcome Collection
Wellcome Library, Creative Commons Attribution (CC BY 4.0), wun3j42p
 
A.Alpha particle strikes helium nucleus and they part at right angles. B. Alpha particle enters nitrogen which ejects proton and becomes nitrogen. Experiments by Blackett in a Wilson Cloud Chamber.
 
LL/92922