\begin{table}%t1
\caption{INTEGRAL payload: key parameters.}
         \label{instruments}
%\begin{center}
{    \begin{tabular}{lll}
            \hline\hline
%        \noalign{\smallskip}
 Parameter & SPI & IBIS \\  
%        \noalign{\smallskip}
            \hline
%            \noalign{\smallskip}
Energy range & 18 keV--8 MeV& 15 keV--10 MeV\\
Detector & 19 Ge detectors, each ($6\times7$) cm& 16384 CdTe dets, each ($4\times4\times2$) mm \\
         & cooled @ 85~K & 4096 CsI dets, each ($8.4\times8.4\times30$) mm \\
Detector area (cm$^2$) & 500 & 2600 (CdTe), 2890 (CsI)\\
Spectral resolution (FWHM) & 3 keV @ 1.7 MeV & 8 keV @ 100 keV\\
Continuum sensitivity & 5.5 $\times$ 10$^{-6}$ @ 100 keV & 6 $\times$ 10$^{-7}$ @ 100 keV\\
(photons cm$^{-2}$ s$^{-1}$ keV$^{-1}$) & 1.2 $\times$ 10$^{-6}$ @ 1 MeV & 5 $\times$ 10$^{-7}$ @ 1 MeV \\
($\Delta E = E/2$, 3$\sigma$, 10$^6$ s) & & \\
Line sensitivity & 3.3 $\times$ 10$^{-5}$ @ 100 keV & 1.9 $\times$ 10$^{-5}$ @ 100 keV\\
(photons cm$^{-2}$ s$^{-1}$) & 2.4 $\times$ 10$^{-5}$ @ 1 MeV& 3.8 $\times$ 10$^{-4}$ @ 1 MeV\\
(3$\sigma$, 10$^6$ s) & & \\
Field of view (fully coded) & 16$^{\circ}$ (corner to corner) & 9$^{\circ}$ $\times$ 9$^{\circ}$ \\
Angular resolution (FWHM)& 2.5$^{\circ}$ (point source) & 12$^{\prime}$ \\
Source location (radius) & $\leq$1.3$^{\circ}$ (depending on source strength) & $\leq$1$^{\prime}$ (for 10$\sigma$ source)\\
Absolute timing accuracy (3$\sigma$) & $\leq$200 $\mu$s & $\leq$200 $\mu$s \\
Mass (kg) & 1309 & 746\\
Power [max/average] (W) & 385/110 & 240/208\\
%\noalign{\smallskip}
            \hline
 Parameter & JEM$-$X & OMC \\  
% \noalign{\smallskip}
            \hline
 %           \noalign{\smallskip}
Energy range & 4 keV--35 keV & 500 nm--600 nm \\
Detector & Microstrip Xe/CH$_{4}$$-$gas detector (1.5 bar)& CCD + $V$-filter \\
Detector area (cm$^2$)& 500 for each of the two JEM-X detectors$^a$ & CCD: (2061 $\times$ 1056) pixels \\
& & Imaging area (1024 $\times$ 1024) pixels \\
Spectral resolution (FWHM) & 2.0 keV @ 22 keV & -- \\
Continuum sensitivity$^b$ & 1.2 $\times$ 10$^{-5}$ @ 6 keV & -- \\ 
(photons cm$^{-2}$ s$^{-1}$ keV$^{-1}$) & 1.3 $\times$ 10$^{-5}$ @ 30 keV & --\\
(3$\sigma$, 10$^6$ s) & & \\
Line sensitivity$^b$ & 1.9 $\times$ 10$^{-5}$ @ 6 keV & --\\
(photons cm$^{-2}$ s$^{-1}$) & 8.5 $\times$ 10$^{-5}$ @ 30 keV & --\\
(3$\sigma$, 10$^6$ s) & & \\
Limiting magnitude (mag) & -- & 17.8 \\
(3$\sigma$, 5000 s) & & \\
Field of view (fully coded) & 4.8$^{\circ}$ & 5$^{\circ}$ $\times$ 5$^{\circ}$ \\
Angular resolution (FWHM) & 3$^{\prime}$ & 25$^{\prime}$$^{\prime}$ \\
10$\sigma$ source location (radius) & $\leq$30$^{\prime}$$^{\prime}$ & 6$^{\prime}$$^{\prime}$ \\
Absolute Timing accuracy (3$\sigma$) & $\leq$200 $\mu$s & $\geq
$1 s \\
Mass (kg) & 65 & 17\\
Power [max/average] (W) & 50/37 & 20/17\\
%\noalign{\smallskip}
            \hline
\end{tabular}}
 \parbox{16.3cm}{
  $^a$ At the moment, only one of the two JEM-X detectors is being operated.\\
$^b$ Assumes operation of both detectors.}
%\end{center}
 \end{table}