Pa-234m

Protactinium-234m (Pa-234m) is a metastable radioactive isotope of protactinium with a half-life of approximately 1.17 minutes. It undergoes beta decay to uranium-234 (U-234). Pa-234m is part of the uranium-238 decay series and is formed as an intermediate product when uranium-238 decays via alpha emission to thorium-234, which subsequently undergoes beta decay to Pa-234m. The "m" in its designation signifies its metastable state, meaning the nucleus is in an excited energy state.

Pa-234m emits gamma radiation as it transitions from its metastable state to a lower energy state. This gamma emission is characteristic of its decay and can be used for detecting and studying the isotope in uranium decay chains. The gamma rays from Pa-234m are important in nuclear spectroscopy and contribute to its identification in uranium-containing materials.

Pa-234m is not found independently in nature but occurs as a transient isotope within the uranium-238 decay series. It is typically present in trace amounts in uranium-containing minerals such as uraninite and pitchblende. Its presence is an indirect indicator of uranium activity and is observed in uranium ore deposits and materials containing uranium. Pa-234m is encountered primarily in controlled laboratory settings during studies of radioactive decay chains or in nuclear industry contexts involving uranium processing.

Visible in the spectra of purified uranium, is not clearly seen in natural uranium due to the presence of Radium-226.