Nuclear radiation can be broadly classified into three categories. These three categories are labeled with the first three letters of the Greek alphabet: ? (alpha), β (beta) and γ (gamma). Alpha radiation consists of a stream of fast-moving helium nuclei (two protons and two neutrons). As such, an alpha particle is relatively heavy and carries two positive electrical charges. Beta radiation consists of fast-moving electrons or positron (an antimatter electron). A beta particle is much lighter than an alpha, and carries one unit of charge. Gamma radiation consists of photons, which are without mass and carry no charge. X-rays are also photons, but carry less energy than gammas. Some materials absorb beta rays. You can measure this absorption by fixing beta source and a radiation monitor so their positions do not change.

Damage of nuclear radiation
It can damage cells and the DNA inside them through its ionizing effect. This effect happens when a high-energy carrying particle or photon removes an electron within an atom's nucleus from its orbit, thereby changing the properties of the atom. If enough ionization occurs DNA, cell and tissue damage result. Radioactive materials can enters the body through breathing, skin wounds and gastrointestinal absorption, causing inside radiation and outside the radiation can penetrate distance are absorbed into the body, make the person were external radiation, damage. Such as fatigue, dizziness insomnia, and skin redness, ulcers, hemorrhage, hair loss, leukemia, vomiting, diarrhea, etc. What's worse ,it can be distortion, hereditary disease incidence, affect the health of several generations. Generally speaking, the more body accept radiation energy, the more serious the radiation sickness symptoms and the greater the risk that the cancer and birth defects.