An alpha particle consists of two protons and two neutrons and is often ... When a radioactive atom emits an alpha particle the mass number decreases by four and the atomic number drops by two.

An alpha particle is also a Helium-4 nucleus ... of the nucleus to increase by one (because there is an extra proton) but the mass number remains the same (because the total number of protons ...

The 5.5 MV Pulsed van-de-Graaff accelerator produces proton, deuteron, alpha particle, or oxygen ion beams in the pulsed or dc mode ... including a determination of the thickness and of the atomic ...