By 1920, physicists knew that most of the mass of the atom was located in a nucleus at its center, and that this central core contained protons. In May 1932 James Chadwick announced that the core also contained a new uncharged particle, which he called the neutron.

To prove that the particle was indeed the neutron, Chadwick measured its mass. He could not weigh it directly. For his mass measurement, Chadwick bombarded boron with alpha particles. Like beryllium, boron emitted neutral rays.

Now called the Rutherford gold foil experiment, or the Geiger–Marsden experiment, these measurements made the extraordinary discovery that alpha particles would occasionally scatter to a high angle when passing through a thin gold foil.

Neutron, neutral subatomic particle that is a constituent of every atomic nucleus except ordinary hydrogen. It has no electric charge and a rest mass equal to 1.67493 × 10−27 kg—marginally greater than that of the proton but nearly 1,839 times greater than that of the electron.

Neutron radiation is the most damaging type of radiation (hence the neutron bomb), a large dose of Neutron radiation is what happens in a criticality accident. This will cause cell death, and destroy the immune system, it generally leads to death within hours to days, but with medical care this could be weeks.

At the conventional effective combat range against modern main battle tanks and armored personnel carriers (< 690–900 m), the blast from a 1 kt neutron bomb would destroy or damage to the point of nonusability almost all un-reinforced civilian buildings.

10 Tips to Limit Your Cell Phone Radiation Exposure

1. Avoid Body Contact.
2. Text More.
3. Use Speaker Mode or a Wired Headset.
4. Shorter Calls.
5. Limit Kids Cell Phone Use Time.
6. Switch Sides of Head When Talking.
7. Avoid Use When Low Signal.
8. Wait For Call Connection.

Gamma rays