XMM Users' Handbook

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EPIC quantum efficiencies

One of the factors to be taken into account when determining the effective area of the EPIC cameras is their quantum efficiency (QE). The QE of both types of EPIC CCD chips as a function of photon energy is displayed in Fig. 19. It is the QE of the EPIC MOS chips that in practice limits the energy passband at its high end, while the pn camera can detect photons with high efficiency up to 15 keV.


  
Figure 19: Quantum efficiency of the two types of EPIC CCD chips (pn and MOS) as a function of photon energy.
\begin{figure} \begin{center} \leavevmode \epsfig{width=0.57\hsize, angle=270, file=figs/epic_qe.eps} \end{center} \end{figure}


European Space Agency - XMM Science Operations Centre