\begin{tikzpicture}[node distance=0.7cm,->,>=stealth',shorten >=0pt]
  \tikzstyle{abstract}=[rectangle, draw=white, rounded corners, fill=white,
    text centered, anchor=north]

  \def\nodeshift{0.8cm}
  \newcommand{\Dsize}{\scriptsize\bf\sf}
  \newcommand{\Esize}{\tiny\sf}

  \Dsize
  \definecolor{red}{RGB}{221,42,43}
  \definecolor{green}{RGB}{132,184,24}
  \definecolor{blue}{RGB}{0,72,112}
  \definecolor{orange}{RGB}{192,128,64}
  \definecolor{gray}{RGB}{107,108,110}
  \colorlet{black}{gray}

  \node (Uranium) [abstract] {\textcolor{gray}{$^\text{238}$U}};
  \node (AuxNode01) [text width=1cm, below=of Uranium] {};
  \node (Bismuth) [abstract, right=of AuxNode01] {\textcolor{blue}{\textbf{$^\text{214}$Bi}}};
  \node (AuxNode02) [below=of Bismuth,yshift=\nodeshift] {{\Esize(\unit[19.9]{min})}};
  \node (Thallium) [abstract, below=of AuxNode02] {$^\text{210}$Tl};
  \node (AuxNode03) [below=of Thallium,yshift=\nodeshift] {{\Esize(\unit[1.3]{min})}};
  \node (Polonium) [abstract, right=of Uranium, xshift=2.5cm,yshift=-0.5cm] {\textcolor{red}{\textbf{$^\text{214}$Po}}};
  \node (AuxNode04) [below=of Polonium,yshift=\nodeshift] {{\Esize\textcolor{red}{\textbf{(\unit[164]{$\boldsymbol{\mu}$s})}}}};
  \node (Lead) [abstract, below=of AuxNode04] {$^\text{210}$Pb};
  \node (AuxNode05) [below=of Lead,yshift=\nodeshift] {{\Esize(\unit[22.3]{y})}};

  \draw[thick, dashed,gray] (Uranium.east) -- ([yshift=0.5cm]Bismuth.west);
  \draw[thick] (AuxNode02.south) -- (Thallium.north);
  \draw[thick,blue] (Bismuth.east) -- (Polonium.west);
  \draw[thick,red] (AuxNode04.south) -- (Lead.north);
  \draw[thick] (Thallium.east) -- (Lead.west);

  \path (0.8,-2) node[anchor=base west] {{\Esize 0.021\%}};
  \path (4.1,-1.5) node[anchor=base west,red] {{\Dsize $\boldsymbol{\alpha}$}};
  \path (2.8,-1.2) node[anchor=base west,blue] {{\Dsize $\boldsymbol{\beta}$}};
\end{tikzpicture}%

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