\begin{table}%t3
%\centering
\small 
\caption{Spectral and time response calibrations: for all
channels (named in Col.~1) we report in the second column the
average frequency, and in the third column the optical bandwidth
$\Delta \nu = \left( \int e(\nu) {\rm d}\nu \right)^2/\!\int e^2(\nu)
\rm d\nu$. Here~$e(\nu)$ are the transmission spectra of Fig.~\ref{fig:specplot}. The conversion factor between Specific
Brightness and CMB temperature fluctuations, as computed from the
same spectra, is reported in the fourth column. Spectral
normalizations and flat band optical efficiencies are measured
using NDF-up load curve power differences. The spectral
normalization~$\eta$ (fifth column) is calculated using the
spectral response from the FTS measurements. The optical
efficiency $\langle \eta e(\nu) \rangle_{\rm band}$ (sixth column) is
calculated assuming a flat spectral response. The detectors are
assumed to be single-moded.  The high optical efficiency of the
345~GHz channels is likely due to propagation of multiple modes to
the detector. The time constant~$\tau$ is reported in the seventh
column, as measured in the laboratory with loading conditions
similar to the flight ones. \label{tab:optical_efficiencies}}
\begin{tabular}{ccccccc}
\hline\hline
\noalign{\smallskip}
%& \multicolumn{2}{|c|}{77K - 90K} \\
%\hline
Channel & $\langle \nu \rangle$ (GHz) & $\Delta \nu$ (GHz) & ${{\rm MJy/sr} \over K_{\rm CMB}}$ & Spec. Norm. & Opt. Eff. & $\tau$ (ms) \\[-3mm]\\
\hline  
145W1 & 147.3 & 46.9 & 388 & 0.35 & 0.26 & 89\\
145W2 & 146.7 & 45.3 & 387 & 0.35 & 0.26 & 50\\
145X1 & 146.2 & 46.1 & 386 & 0.37 & 0.28 & 58\\
145X2 & 146.6 & 45.5 & 387 & 0.33 & 0.25 & 43\\
145Y1 & 147.0 & 46.7 & 388 & 0.38 & 0.29 & 97\\
145Y2 & 146.8 & 46.6 & 387 & 0.38 & 0.31 & 82\\
145Z1 & 147.0 & 46.2 & 388 & 0.26 & 0.19 & 66\\
145Z2 & 147.1 & 47.6 & 388 & 0.21 & 0.14 & 81\\
\hline
245W  & 248.0 & 94.6 & 461 & 0.38 & 0.33 & 12\\
245X  & 250.7 & 87.6 & 460 & 0.36 & 0.28 & 20\\
245Y  & 244.0 & 89.6 & 465 & 0.33 & 0.27 & 15\\
245Z  & 247.6 & 96.0 & 461 & 0.32 & 0.27 & 16\\
\hline
345W  & 340.3 & 134.7 & 321 & 0.81 & 0.70 & 7.9\\
345X  & 338.9 & 137.1 & 323 & 0.89 & 0.77 & 8.0\\
345Y  & 344.1 & 131.7 & 314 & 0.82 & 0.72 & 4.7\\
345Z  & 337.8 & 131.3 & 326 & 0.87 & 0.68 & 12\\
\hline
\end{tabular}
\end{table}