\begin{table}%t6
\caption{\label{JMLTab:4Kcooler}Basic characteristics of the 4~K cooler.}
%\centering
\par
\begin{tabular}{ll}
\hline 
\hline \noalign{\smallskip}
Working fluid &  \element[][4]{He}  \\  
Maximum cooling power at 17.5~K pre-cooling temperature & 19.2~mW   \\  
Required cooling power at 17.5~K pre-cooling temperature & 13.3~mW  \\  
Pre-cooling stages & Third V Groove 54~K Sorption cooler LR3 17.5--19~K \\
Nominal operating temperature & 4.5~K \\
Mass & ~ \\
 ~ ~ Compressors, pipes, cold stage, ... & 27.7~kg \\
 ~ ~ Electronics and current regulator  & 8.6~kg \\
Power & 120~W Max into current regulator \\ 
\hline
\end{tabular}
\end{table}