如何在表格中添加垂直线？

Question

我正在制作桌子，但无法显示垂直线。我遵循了一些示例，但它们仍然没有出现。

\begin{table}[h!]
\centering
\begin{tabular}{||c c c c||} 
\hline
\multicolumn{4}{|c|}{Telescope Data} \\
\hline
Channels & \makecell{Beam Size\\ (arcsec)} & \makecell{Noise \\ (mJy/beam)} & Position of Peak Flux \\ [0.5ex] 
\hline
1-10 & \makecell{\textbf{min:} 1.42 \\ \textbf{max:} 1.95}  & 4.9928 & \makecell{\textbf{peak(x):} 15 \\ \textbf{peak(y):} -13.5 \\ \textbf{peak(flux, max):} 0.002846} \\ [3ex] 
\hline 
52-61 & \makecell{\textbf{min:} 1.423 \\ \textbf{max:} 1.95}  & 0.0018912 & \makecell{\textbf{peak(x):} -0.25 \\ \textbf{peak(y):} 0 \\ \textbf{peak(flux, max):} 0.029341} \\ [3ex] 
\hline
103-112 & \makecell{\textbf{min:} 1.427 \\ \textbf{max:} 1.956}  & 0.000802855 & \makecell{\textbf{peak(x):} -16 \\ \textbf{peak(y):} 0 \\ \textbf{peak(flux, max):} 0.00241892} \\ [3ex]  
\hline
\end{tabular}
\end{table}