Radioactive sources in betavoltic nuclear batteries

Betavoltaic technology represents a direct energy conversion approach that utilizes the decay energy of radioisotopes containing beta radiation to generate electrical energy over long periods of time. Such nuclear batteries offer advantages for applications requiring long operating life with minimal maintenance, particularly in remote or inaccessible environments. This thesis provides a comprehensive review and analysis of scientific research focusing on radioactive sources, which are the most important component of betavoltaic batteries. Important radioisotopes such as Strontium-90/Therium-90 (90Sr/90Y), Promethium-147 (147Pm), Carbon-14 (14C), Nickel-63 (63Ni), Tritium (3H) are examined based on critical selection criteria such as half-life, beta emission energy, specific activity, power density, decay characteristics, availability, cost, and safety considerations. Methods for isotope production, source production, and source characterization are examined.