How fast do alpha particles travel

In the case of lower energy beta particles, the outer layer of clothing can act as an effective shield. Gamma rays can be emitted from the nucleus of an atom during radioactive decay. They are able to travel tens of yards or more in air and can easily penetrate the human body. Shielding this very penetrating type of ionizing radiation requires thick, dense material such as several inches of lead or concrete.

Neutrons can be released from the nucleus of an atom during a fission reaction, such as within a nuclear reactor, or upon detonation of a nuclear weapon. Neutrons, like gamma rays, are very penetrating and several feet of concrete is needed to shield against them.

After the beta particle has lost its kinetic energy, it will eventually find its way into the electronic structure of an atom or molecule. It cannot again be emitted by a nucleus because it is impossible for such an electron to enter into a stable nucleus. While this may seem strange because the beta particle originated from the transformation of a neutron into a proton and an electron, the electron does not stay within the nucleus, rather it is immediately ejected as the beta particle.

It is possible for some unstable nuclei to capture electrons from the inner electron shells of the respective atoms. This process is somewhat the opposite of beta decay in that the captured electron immediately combines with a proton to produce a neutron.

This reaction, however, requires a significant amount of energy, which is not available in stable atoms; only some specific unstable i. Answer posted on 17 May The information posted on this web page is intended as general reference information only. Alpha particles lack the energy to penetrate even the outer layer of skin, so exposure to the outside of the body is not a major concern. Inside the body, however, they can be very harmful.

If alpha-emitters are inhaled, swallowed, or get into the body through a cut, the alpha particles can damage sensitive living tissue. The way these large, heavy particles cause damage makes them more dangerous than other types of radiation. The ionizations they cause are very close together - they can release all their energy in a few cells.

This results in more severe damage to cells and DNA. These particles are emitted by certain unstable atoms such as hydrogen-3 tritium , carbon and strontium Beta particles are more penetrating than alpha particles, but are less damaging to living tissue and DNA because the ionizations they produce are more widely spaced.

They travel farther in air than alpha particles, but can be stopped by a layer of clothing or by a thin layer of a substance such as aluminum. However, as with alpha-emitters, beta-emitters are most hazardous when they are inhaled or swallowed. Unlike alpha and beta particles, which have both energy and mass, gamma rays are pure energy. Gamma rays are similar to visible light, but have much higher energy.

Gamma rays are often emitted along with alpha or beta particles during radioactive decay. Gamma rays are a radiation hazard for the entire body.

They can easily penetrate barriers that can stop alpha and beta particles, such as skin and clothing. Gamma rays have so much penetrating power that several inches of a dense material like lead, or even a few feet of concrete may be required to stop them. Gamma rays can pass completely through the human body; as they pass through, they can cause ionizations that damage tissue and DNA. Because of their use in medicine, almost everyone has heard of x-rays. X-rays are similar to gamma rays in that they are photons of pure energy.

X-rays and gamma rays have the same basic properties but come from different parts of the atom. X-rays are emitted from processes outside the nucleus, but gamma rays originate inside the nucleus. They also are generally lower in energy and, therefore less penetrating than gamma rays.