Search for a fine structure in the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi mathvariant="normal">C</mml:mi></mml:mrow><mml:mprescripts/><mml:mrow/><mml:mrow><mml:mn>14</mml:mn></mml:mrow><mml:mrow/><mml:mrow/></mml:mmultiscripts></mml:mrow></mml:math>decay of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi mathvariant="normal">Ra</mml:mi></mml:mrow><mml:mprescripts/><mml:mrow/><mml:mrow><mml:mn>222</mml:mn></mml:mrow><mml:mrow/><mml:mrow/></mml:mmultiscripts></mml:mrow></mml:math>

The $^{14}\mathrm{C}$ decay of $^{222}\mathrm{Ra}$ has been reinvestigated, using an 85 MBq activity $^{230}\mathrm{U}$ source radiochemically separated, a Si barrier detector, and a superconducting magnetic spectrometer. In a 16 days counting run, 210 $^{14}\mathrm{C}$ events were recorded. The $^{14}\mathrm{C}$ particles energy value 30.930\ifmmode\pm\else\textpm\fi{}0.090 MeV was found and an upper limit b\ensuremath{\le}2\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}12}$ was estimated for the $^{14}\mathrm{C}$ branching ratio to the $^{208}\mathrm{Pb}$ first excited state; the branching-ratio value to the $^{208}\mathrm{Pb}$ ground state, thus equal to the total branching ratio, was found to be b=${\ensuremath{\lambda}}_{\mathit{c}}$/${\ensuremath{\lambda}}_{\mathrm{\ensuremath{\alpha}}}$=(2.31\ifmmode\pm\else\textpm\fi{}0.31)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}10}$.