XMM Users' Handbook

   
RFC chip arrays

MM

Fig. 46 displays a sketch of the chip geometry in an RFC. The two RFCs will be offset with respect to each other along their dispersion direction so as to fill the gaps in between each other's chips (i.e., providing continuous coverage along the dispersion direction).

  

Figure 46: Sketch of an RFC chip array, with 9 MOS CCDs. The half of each CCD at large camera-y coordinates is exposed to the sky, the other half is used as a storage area. The -1. order spectrum of a source observed on-axis starts on the left chip. The dispersion direction is along the ``Z'' axis, so that higher energies are dispersed to higher values in Z.

The chip on the left side of Fig. 46 has number 1 (the low Z end of the coordinate scale), the one on the right is number 9 (high Z value). For an on-axis source, the individual chips cover approximately the energy ranges listed in Table 9. The numbers tabulated there relate to a nominal case (the design geometry). Detailed simulations should be performed in case the user is interested in lines that are close to the chip boundaries. To move important lines away from chip boundaries, users may want to consider changing the pointing (boresight coordinates) accordingly and observing with a fixed position angle.

 

Table 9: The wavelength and energy ranges covered by the chips of RGS for an on-axis source, for the design instrument geometry

$\parbox{2cm}{{\bf Chip no.}}$	Energy Range [eV]		Wavelength Range [Å]
	-1. order	-2. order	-1. order	-2. order
1	328.2-374.3	656.4-748.7	37.78-33.12	18.89-16.56
2	374.9-432.4	749.9-864.8	33.07-28.67	16.53-14.34
3	433.1-506.1	866.3-1012.3	28.62-24.50	14.31-12.25
4	507.1-602.2	1014.2-1204.5	24.45-20.59	12.22-10.29
5	603.5-731.6	1207.0-1463.1	20.54-16.95	10.27-8.47
6	733.3-913.2	1466.6-1826.4	16.91-13.58	8.45-6.79
7	915.7-1183.5	1831.4-2367.0	13.54-10.48	6.77-5.24
8	1187.4-1622.0	--	10.44-7.64	--
9	1628.6-2440.2	--	7.613-5.08	--