Sievert and GrayĪbsorbed dose is defined as the amount of energy deposited by ionizing radiation in a substance. The energy is transferred in small quantities for each interaction between the radiation and a molecule and there are usually many such interactions. People can neither see nor feel radiation, yet it deposits energy to the molecules of the body. The danger of ionizing radiation lies in the fact that the radiation is invisible and not directly detectable by human senses.
![cyrstal convert table radiation island cyrstal convert table radiation island](http://mcleodedtech541.weebly.com/uploads/7/0/0/7/70075383/1864591_orig.png)
If the source is too intensive and time or distance do not provide sufficient radiation protection, the shielding can be used. Finally, the radiation dose also depends on the material between the source and the object. The amount of radiation exposure depends directly (linearly) on the time people spend near the source of radiation. This analogy, in a certain sense, can be applied to radiation also from radiation sources. If you are too far from heat source, the insufficiency of heat can also hurt you. If you are at the right distance, you can withstand there without any problems and moreover it is comfortable. Similarly to a heat from a fire, if you are too close, the intensity of heat radiation is high and you can get burned. The amount of radiation exposure depends on the distance from the source of radiation. On the other hand electrically neutral particles interacts only indirectly, but can also transfer some or all of their energies to the matter. For example charged particles with high energies can directly ionize atoms. Each type of radiation interacts with matter in a different way. Activity of the source directly influences the radiation dose deposited in the material. Generally, the radiation dose depends on the following factors regarding to the radioactive source: It is therefore very important to distinguish between radioactivity of a radioactive source and the radiation dose which may result from the source. However, when people or another system (also non-biological) are exposed to radiation, energy is deposited in the material and radiation dose is delivered. But any radioactive source represents no biological risk as long as it is isolated from the environments. In previous chapters, we have discussed radioactivity and the intensity of a radioactive source, measured usually in becquerels.
![cyrstal convert table radiation island cyrstal convert table radiation island](https://i1.wp.com/www.dqtravel.net/wp-content/uploads/2019/01/19-6-18-2625-2.jpg)
But what is the relationship between becquerels (radioactivity) and sieverts (equivalent dose)? The sievert represents the equivalent biological effect of the deposit of a joule of gamma rays energy in a kilogram of human tissue. In radiation protection, the sievert is a derived unit of equivalent dose and effective dose.