When it comes to radiation, gamma rays have the most penetrating power of all three sources. Neutrinos, particles with no electrical charge or measurable mass, are the most penetrating type of radiation. According to The New Quantum Universe by Tony Hey and Patrick Walters, a neutrino has to go through many light years of matter to have a 50-50 chance of interacting with the nucleus of an atom. This makes them able to easily pass through the Earth.
Gamma rays are a radiation hazard to the entire body and can penetrate barriers that stop alpha and beta particles, such as skin and clothing. It may take several inches of dense material like lead or even a few feet of concrete to stop them. Gamma rays can completely pass through the human body, causing ionizations that damage tissues and DNA. Alpha particles have a very limited ability to penetrate other materials.
They can be blocked with a sheet of paper, skin, or even a few centimeters of air. However, materials that emit alpha particles are potentially hazardous if inhaled or swallowed, but external exposure generally does not pose a hazard. The Environmental Protection Agency (EPA) is responsible for protecting human health and the environment from ionizing radiation that comes from human use of radioactive elements. Ionizing radiation (such as x-rays and cosmic rays) is more energetic than non-ionizing radiation and may include alpha particles.
Alpha particles are composed of two neutrons and two protons and are a form of particulate ionizing radiation. The other form of radiation is known as particle radiation which consists of tiny, fast-moving particles that have energy and mass (weight).
