XMM RPS Users' Manual

   
Filling in RGS exposure settings

For RGS more details must be specified, depending on the instrument mode in which observations are to be carried out. These can be defined on a dedicated page, which is accessed by pressing the ``Add Details'' button at the bottom of the exposure page.

At present, only the RGS CCD readout sequence is a user-selectable parameter. For normal observations over the whole energy range of the RGS, this sequence should not be changed. Only if users want to perform spectroscopy only over a part of the RGS passband or read out one or more chips faster than others, a different sequence can be chosen here. Each RGS has 9 CCD chips, but is read out in a cycle with up to 12 readout slots. The energy ranges covered by the different RGS CCDs in different grating orders are described in the UHB chapter about RFC arrays (RFC standing for RGS Focal Camera). If a user should wish to read out a chip onto which a particularly strong and scientifically important line falls (e.g., no. 3) more often than all others, a readout sequence of, e.g., [3 1 2 3 4 5 3 6 7 3 8 9] could be chosen, with which chip#3 is read out 4 times as often as the others. In this manner photon pile-up in bright emission lines can be avoided, if it should be a concern for the proposed science.

When the ``HTR SINGLE CCD'' mode is used, only one CCD is read out. Accordingly, all readout slots must have the same CCD number in this case. Please fill the number of the CCD that should be read out into the form.