to ensure you have ample time to leave the radiation area. This can also be closely monitored by the use of dosimeters with dose alarms built in. These alarms can warn the user when they have reached pre-prescribed intervals and give them enough time to vacate the area.
10 Radiological Casualties Minimizing distance seems to be an easy premise to grasp, however once you understand how much a simple couple feet could actually matter, it is quite eye-opening. The inverse square law gives us a simple mathematical equation to calculate radiation levels based on confirmed readings at prescribed distances. The formula reads intensity1/intensity2 = distance2^2/distance1^2. Simplified it equates to double the distance equals quarter the dose, or inversely, half the distance quadruples the dose. Over great distances this does not seem to matter much because the dose rate will not change drastically, however when you are possibly working a radiological incident and are a couple feet from a high-gamma emitting radiological source, moving a couple more feet back couple reduce the dose rate by a factor a four. It is imperative that personnel use detection equipment and be proficient in how they work, it could save their life. The final factor to limiting exposure to radiation is shielding. Traditionally speaking this is done by placing shielding around the source or placing the source within a shielded container (pig). The types of materials that are good for shielding radioactive sources are those that are heavy dense materials like lead. The core concept behind shielding radioactive sources is called half value layers. Half value layers are prescribed thicknesses of various materials that will reduce a certain radioactive source by half. With each half value layer added it will reduce the remaining radiation by half. The Nuclear Regulatory Commission has put out a chart with the following materials half value layers for various nuclear energies; uranium, tungsten, lead, iron, concrete, and water. For instance, the half value layer of Cobalt-60, a high gamma emitter, is 1.2cm of lead or 6.2cm of concrete. (NRC, 2013) During a disaster situation or radiological incident, it might not be too easy to find a couple centimeters of lead laying around to provide responders protection. Therefore, we must
11 Radiological Casualties rely on time, distance, and PPE (personal protective equipment) as that will be the shielding of your body from some of the radiological affects you may encounter. Responders should be well equipped with respiratory protection as their highest priority during a radiological incident. As we discussed earlier, alpha and beta particles are especially harmful if inhaled, ingested, or absorbed into the bloodstream. High filtration masks should be worn at a minimum, air-purifying respirators for additional protection, and positive air pressure self-contained breathing apparatus’ for maximum protection. Protective clothing is also a good idea to wear in order to protect your skin from contamination. Like we learned previously, your skin may stop alpha particles, but not always beta particles. Electro-magnetic radiation such as gamma rays and x-rays will penetrate