When you speak of dangerous radiation exposure are you generally speaking of alpha radiation beta radioation or gamma radiation?

Answer 1

For external exposure, normally gamma radiation. Alpha particles and beta particles are easy to stop; gamma is high-energy rays so it passes through many things. For internal exposure, ingestion or inhalation, Alpha and Beta are the larger dangers. A Gamma particle is just a photon, it can just zip through you, leaving part of it's energy behind in each cell it penetrates, sometimes hitting something important like DNA, sometimes knocking an electron off one of the elements that make up the cell. Removing electrons in this manner is called ionization, which is why it is called Ionizing radiation. An Alpha particle by comparison is quickly stopped in the digestive tract or lungs, depositing it's energy in one spot, creating more damage. It is also a large particle, although it can be argued that it also acts as a wave of energy. One important point. Most "radioactive elements" are quite safe until they decay. If the half life is long enough, there won't be a large amount of radiation. Why? Because the radiation isn't produced until an atom breaks down, resulting in the next lower element in the decay chain and a burst of radiation, sometimes several types. The shorter the half life, the more radiation in a short time. An ingested or inhaled radioacitve particle like Radon is not finished after it decays and sends off it's burst of radiation. There are 12 more decays to follow, some in quick succession, sometimes mere seconds, others last a minutes, some last for days, some with large amounts of energy. What makes Radon so dangerous is that as Radium decays, it turns into the radioactive gas Radon, and it can float around in the air for the next 3.8 days half life and beyond. If you breath the Radon in, and it happens to decay inside your lungs, or worse, it is in your blood stream when it decays, you now have a sticky heavy metal particle of polonium 218 inside your body. Several studies have suggested a possible link between alzheimers and Parkinsons disease, as elevated levels of Radon daughter products (progeny or lower elements in the decay chain) were found after autopsy of the victims of the diseases. Still, the type of radiation may not be as important as the energy level. As an example, we had one of our dogs X rayed a few weeks ago. X rays are rated in keV, kilo electron Volts. For a medical X ray, a 80 keV level is used, depending on the thickness of the body part. In comparison, a granite countertop containing uranium and it's decay products does put off a lot of 40 to 100 keV level Gamma rays, which are the same as X rays except for their point of origins. But, some of the gamma radiation coming from the stone is 200, 400, 800, even 2,000 keV and above. Note that the decay chain link below won't always show the Gamma radiation from the decay, just the major source. As an example Potassium 40 will have only 13% Gamma radiatoin and 87% Alpha radiation from a decay.