Editing Tantalum (section)

===Isotopes===
{{Main|Isotopes of tantalum}}

Natural tantalum consists of two stable [[isotope]]s: <sup>180m</sup>Ta (0.012%) and <sup>181</sup>Ta (99.988%). <sup>180m</sup>Ta (''m'' denotes a metastable state) is predicted to decay in three ways: [[isomeric transition]] to the [[ground state]] of <sup>180</sup>Ta, [[beta decay]] to <sup>180</sup>[[Tungsten|W]], or electron capture to <sup>180</sup>[[Hafnium|Hf]]. However, radioactivity of this [[nuclear isomer]] has never been observed, and only a lower limit on its [[half-life]] of 2.9{{e|17}}&nbsp;years has been set.<ref>{{cite journal | author= Majorana Collaboration | title=Constraints on the Decay of <sup>180m</sup>Ta | journal=Physical Review Letters | volume=131 | issue=15 | date=2023-10-11 | page=152501 | issn=0031-9007 | doi=10.1103/PhysRevLett.131.152501| pmid=37897780 | arxiv=2306.01965 }}</ref> The ground state of <sup>180</sup>Ta has a half-life of only 8 hours. <sup>180m</sup>Ta is the only naturally occurring [[nuclear isomer]] (excluding [[radiogenic]] and [[cosmogenic]] short-lived nuclides). It is also the rarest primordial isotope in the Universe, taking into account the elemental abundance of tantalum and isotopic abundance of <sup>180m</sup>Ta in the natural mixture of isotopes (and again excluding radiogenic and cosmogenic short-lived nuclides).<ref name="NUBASE">{{NUBASE 2003}}</ref>

Tantalum has been examined theoretically as a "[[Salted bomb|salting]]" material for [[nuclear weapon]]s ([[cobalt]] is the better-known hypothetical salting material). An external shell of <sup>181</sup>Ta would be irradiated by the intensive high-energy neutron flux from a hypothetical exploding nuclear weapon. This would transmute the tantalum into the radioactive isotope <sup>182</sup>Ta, which has a [[half-life]] of 114.4 days and produces [[gamma ray]]s with approximately 1.12 million electron-volts (MeV) of energy apiece, which would significantly increase the radioactivity of the [[nuclear fallout]] from the explosion for several months. Such "salted" weapons have never been built or tested, as far as is publicly known, and certainly never used as weapons.<ref>{{cite journal|last1=Win|first1=David Tin|last2=Al Masum|first2=Mohammed|title=Weapons of Mass Destruction|date=2003|journal=Assumption University Journal of Technology|volume=6|issue=4|pages=199–219|url=http://www.journal.au.edu/au_techno/2003/apr2003/aujt6-4_article07.pdf}}</ref>

Tantalum can be used as a target material for accelerated proton beams for the production of various short-lived isotopes including <sup>8</sup>Li, <sup>80</sup>Rb, and <sup>160</sup>Yb.<ref>{{cite web |title=Tantalum Target Yields – ISAC Yield Database – TRIUMF: Canada's National Laboratory for Particle and Nuclear Physics |url=https://mis.triumf.ca/science/planning/yield/target/Ta |website=mis.triumf.ca}}</ref>