promethium147

Promethium-147, or 147Pm, is a radioactive isotope of the lanthanide promethium. It has an atomic number of 61 and a mass number of 147. There are no stable isotopes of promethium, and 147Pm is produced artificially in nuclear reactors and, to a lesser extent, in particle accelerators. It is available as a sealed radioactive source for specialized industrial and scientific uses, and its handling is subject to regulatory controls.

Decay and dating aspects: 147Pm decays by beta minus emission to 147Sm (samarium-147) with a half-life of about 2.62 years. The daughter isotope 147Sm is long-lived and, through further decay, contributes to the natural Sm-Nd decay system, with 147Sm decaying to 143Nd over geological timescales. This decay chain underpins some radiometric dating contexts, though 147Pm itself is primarily utilized for its short-to-intermediate activity.

Production: 147Pm is not found naturally in meaningful amounts. It is produced in nuclear reactors as a fission product or by irradiation of target materials in accelerator facilities. The isotope is then separated and packaged as a controlled radioactive source for specific applications.

Applications and regulation: Historically, 147Pm has been used as a beta-emitting source in luminous paint for instrumentation dials and in various calibration and industrial devices. Its use has declined in some areas due to safety, regulatory, and supply considerations, with alternative isotopes or solid-state technologies often preferred today. As with all radioactive sources, 147Pm handling requires proper licensing, shielding, containment, and waste management to minimize exposure to workers and the environment.

Safety: 147Pm emits beta radiation; exposure is minimized through sealed sources, proper handling protocols, ventilation, and regulatory oversight. Ingestion or inhalation poses health risks, and disposal must follow established radioactive-waste guidelines.