Samarium-153
Decay Scheme
What is a decay scheme?
A decay scheme diagram is a visual representation of a radioactive decay process that shows the most probable paths of decay. The vertical distance between the lines is proportional to the total amount of energy released during the emission of the particle. The arrows slanting to the right indicate an increase in atomic number, whereas arrows slanting to the left would indicate a decrease in atomic number. The percentages next to each emission describe how often that particle is emitted with that specific energy.
Decay scheme for samarium-153
In this decay scheme, the line representing the parent nuclide (samarium-153) is drawn above and to the left of the daughter nuclide (europium-153), since the atomic number is increasing by one. As you can see, there are many paths of decay for this nuclide, but the most prevalent is that of a 704 keV negatron and a 103 keV gamma emission. The total transition energy required to transform from samarium-153 to europium-153 is 807 keV, as shown by the figures on the right hand side of the scheme denoting the energy at each horizontal line. While not always the result from the decay of a radionuclide, the daughter product of samarium-153 is stable; making it ideal for medical use as there is no danger of unintended additional radiation exposure to the patient.