Nuclear literacy and radiation effects in Hungary

摘要

More than 60% of natural radioactivity at home is coming from radon, the nobel gas. After its radioactive decay the daughter elements are also radioactive. The β- and α-particles are electrically charged. This means that after the radioactive decays electrically charged ions are born. It is a good question to ask your students whether these ions are positive or negative. You can be almost sure that all of your students' answer will be: "It depends on the decay. After a β~- decay the daughter element will be positively charged, but after an α-decay (α = He~(++)) the daughter element will be negatively charged." BUT NO! The relative heavy and charged a-particle will tear quite a lot of electrons from the atomic shell. So if radon gas is present in the air there are positive ions, and they are even radioactive as well. If you blow up a balloon, and you rub it by your freshly washed hair, it will be electrically negative. This balloon is able to collect the positive ions from the air. Now, it is easy to make an experiment with a Geiger counter. Do not forget to measure the background before you blow up the balloon! (It was 40 clicks/minute in Nagasaki at the ISRE Symposium.) Then the rubbed balloon should be taken into a closed room closed to the ground. (The main source of radon is the natural radium content of the soil. In Nagasaki, in the Brick Hall the small room just behind the doorman desk was "excellent".) To collect the ions about 30 minutes is needed. Then let the air come out from the balloon! It is important! There was a big balloon surface during the collection time. Now, without air in it, on the smaller surface the density of the collected radioactive isotopes is much higher. (As it happened in Nagasaki at the ISRE Meeting: the Geiger counter showed 1000 clicks/minute!)