Identification of new isomers in $$^{228}$$Ac: impact on dark matter searches
Identification of new isomers in $$^{228}$$Ac: impact on dark matter searches
Abstract We report the identification of metastable isomeric states of $$^{228}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mrow /><mml:mn>228</mml:mn></mml:msup></mml:math> Ac at 6.28 keV, 6.67 keV and 20.19 keV, with lifetimes of an order of 100 ns. These states are produced by the $$\beta $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>β</mml:mi></mml:math> -decay of $$^{228}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mrow /><mml:mn>228</mml:mn></mml:msup></mml:math> Ra, a component …