Alpha particles comprise 2 neutrons and 2 protons. Because of their large mass and relatively slow speed, alpha particles are the least penetrating of the three types of radiation, and can be stopped ...

If you want to measure radioactivity, nothing really beats a Geiger counter: compact, rugged, and reasonably easy to use, they’re by far the most commonly used tool to detect ionizing radiation.

Broser and Kallmann 1 have shown that mono-energetic alpha-particles give pulses of the same height in a scintillation counter, and that the pulse-height is proportional to the energy of the ...