Polonium - Po

Polonium is a chemical element, which is in the periodic table with the symbol Po. Marie Curie whose native country was Poland discovered it in 1984, and therefore named after the country. If I remember my Ordinary Level Chemistry correctly, an atomic number 84 means it has 84 protons within its nuclei.

Usually found in uranium ore, a bombardment of electrons may also artificially create it. It has a very short half-life of 138 days, which means that its radioactive decay falls by exactly half in 138 days. Therefore, if you were to measure the rate of decay, and it calculated to around 138-days, then that is the signature hallmark of this element.

Isotopes

Polonium also has isotopes such as the famous Po-210. An isotope simply means that the element can exist with a different number of neutrons in its nuclei. Neutrons have no charge, and only mass, and therefore they only alter the weight of the element.

Alpha Particles

Polonium emits alpha particles, which has an average energy level of around 5.3 MeV. Since the particles do not have much energy, they can travel just a few centimetres in the air. In addition, being positively charged makes them unable to penetrate barriers because the positive nuclei of other atoms repel them. They also lose their energy very quickly and neutralise within 0.000000000006-seconds to create a neutral helium atom.

Air molecules, or 0.005 cm of water, or just a sheet of paper easily stops these particles, and therefore they are relatively harmless in the air, however if they are ingested they can cause serious biological damage to cells.

Having a short half-life and short range makes them very difficult to detect, however accurate detection is dependent on statistical calculations as it is with physical detection through ionisation. One must first measure the background radiation, which subtracts from the source value. If the average of the half-life values extrapolates to 138-days then polonium verification is positive. The accuracy of the measurement depends upon the amount of time allowed to measure the sample and the background radiation. With the use of a miniature microcontroller, it is possible to perform powerful statistical calculations to extrapolate its presence.

Detectors

Currently on the Internet, there are a huge number electronic laboratory machines available to measure Po-210, for example, the LB 124 SCINT can accurately measure extremely low levels of alpha particles to a high degree of accuracy, and used by scientists all over the world. Currently, no detector exists that is pocket-sized, which can accurately detect the presence of Po-210.

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