\setlength{\unitlength}{1mm}
\begin{picture}(60,50)
\put(0 ,15){\vector(1,0){53}}
\put(54,14){$x_A$}
\put( 8,10){\vector(0,1){37}}
\put( 0,46){$ct_A$}
\multiput(13,9)(15,0){3}{\line(0,1){35}}
\put(11,5){$A''$}
\put(26,5){$A'$}
\put(41,5){$A'''$}
\multiput(13,37)(30,0){2}{\circle*{2}}
\put(28,22){\circle*{2}}
\put(28,22){\vector(1,1){14}}
\put(15,39){$E_1$}
\put(28,22){\vector(-1,1){14}}
\put(45,39){$E_2$}
\multiput(0,37)(4,0){13}{\line(1,0){2}}
\end{picture}